# The Opamp thread



## ROBSCIX

Hey guys, many of use test opamps in various equipment but it seems a great deal of the informaiton and discussion is going on in other threads or behind the scenes where people cannot find it. I figured this thread would be a great idea for those testing.


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## Bilavideo

I bought a Cmoy from BSG who installed an Opa 2227 and, for a few dollars more, sent me an LRM4562. After that, I got so excited about opamp rolling that I went through Ebay (bad idea), Digikey and AD for more. I've tested the 627BP, AD8599, AD8066, AD797, Opa27, AD823, AD825 and a few more. For single opamps, I went through Cimarron Technologies to order Browndog Adapters.


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## ROBSCIX

I just finished soldering up a bunch of new modules last night. All SOIC chips, some requiring two chips per module.
 Looking forward to doing some testing tommorow. I would Avoid Ebay as many say they have gotten bad units or fakes etc. I would prefer to pay more and make sure I am getting quality opamps. I think more people are getting into opamp swapping now as more and more of the modern soundcards are coming equipped with opamp sockets.


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## fzman

without violating the TOS regarding selling in no for-sale forums, perhaps we could figure out a way for people to swap or pass-along orphaned opamps. anybody have an ideas-- chime in.

 also, it might be nice to have people post fairly specific comments, e.g., component, position, general results, and likes/dislikes, so we have a firmer basis for comparison.

 maybe even a forum/subforum/thread with links to data sheets in one, easy to search place.

 robcsix -- good idea to start this thread


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## hopeless

Quote:


  Originally Posted by *Bilavideo* /img/forum/go_quote.gif 
_I bought a Cmoy from BSG who installed an Opa 2227 and, for a few dollars more, sent me an LRM4562. After that, I got so excited about opamp rolling that I went through Ebay (bad idea), Digikey and AD for more. I've tested the 627BP, AD8599, AD8066, AD797, Opa27, AD823, AD825 and a few more. For single opamps, I went through Cimarron Technologies to order Browndog Adapters._

 

For my 24V CMOY the best I've heard so far is 2x AD845KN. Tried also the OPA627BP, AD8620, TLE2082, OPA2111, AD797AN, and many more (not AD825 and AD8599 though).

 Also 2x AD843JN was really good, but got really warm due to high quiescent current. Finally, I also loved the LT1361 there (about equal to the 2x AD845KN but different).


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## ROBSCIX

I just built two 8599's modules last night but I haven't tested them yet though.


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## hopeless

Please someone try the LT1355 (or the single LT1354) to support my impression that it is very transparent 
	

	
	
		
		

		
			







 It is a single stage opamp, and that probably explains why I like it and the rest of the series so much (as well as the LT1469). I like everything that sounds direct and emotional, yet subtle. The multiple stage opamps (like the LT1028 which is three-stage) tend to sound more artificial somehow. I bet that the LME's are also two-stage or three-stage.


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## Pluto2

Anyone has experience on LT1352? 

 Do you know where I can buy them, I need about 10 pieces?


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## hopeless

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Anyone has experience on LT1352? 

 Do you know where I can buy them, I need about 10 pieces?_

 

I would suggest that you rather use the LT1355.


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## 12Bass

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Anyone has experience on LT1352? 

 Do you know where I can buy them, I need about 10 pieces?_

 

IIRC, Digi-Key has them. A decently clear-sounding opamp if low current is a requirement. I'm using one in the preamp for my 12-string bass.

 Also, I've amassed a variety of chips over the past couple of years which others might be interested in.


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## 12Bass

Of the chips I've tried so far, I've found the OPA211 preferable to most others (including the LM/LME chips). Hopefully the OPA2211A will be similar. OPA827 sounds pretty good too, IMO, if a FET is required. Heard lots of good things about the AD797 but haven't tried it yet... still sitting in the package.


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## hopeless

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Of the chips I've tried so far, I've found the OPA211 preferable to most others (including the LM/LME chips). Hopefully the OPA2211A will be similar. OPA827 sounds pretty good too, IMO, if a FET is required. Heard lots of good things about the AD797 but haven't tried it yet... still sitting in the package._

 

I agree with you. Have you tried LT1357/1358 and LT1354/1355 ?


 The AD797 is nice, especially for bass quality and neutral tonality. Sound(ed) a little dry for me though.


 The AD8599 still remains a mystery for me (until I manage to hear it 
	

	
	
		
		

		
		
	


	




).


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## Pluto2

Oh, I noticed that Jim Williams recommended LT1352 for filtering applications (which I need) since its input bias current is low (for BJT opamps) while LT1358 with high bias current is not suitabe there.....

 Or any better suggestion other than LT1352 for filters?

 BTW, any opamp has interesting quality for mid and bass?


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## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Of the chips I've tried so far, I've found the OPA211 preferable to most others (including the LM/LME chips). Hopefully the OPA2211A will be similar. OPA827 sounds pretty good too, IMO, if a FET is required. Heard lots of good things about the AD797 but haven't tried it yet... still sitting in the package._

 

Yes, the OPA211 is a great chip had a quick listen to it a few hours ago and I am impressed. The OP827 is also a great new opamps that many are raving about. I built four of those and have done some quick tests also.
 I have an AD797 but I found it was good but not as "amazing" as some say it is. Although it depends on the gear and position in the circuit. Hopefully I will get some time to test more thoroughly later today.


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## Ashkii21

I've built a couple of Cmoys, so my knowledge of opamps is limited. 
	

	
	
		
		

		
		
	


	




 I've tried the OPA2132, OPA2227, and the TLE2072. I am only using 1 9V battery and the best one for me that I've tried so far is the TLE2072. I was thinking of trying a TLE2082. Are there any other opamps that will work with just a single 9V battery supply? I would like to try a couple more.


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## hopeless

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Oh, I noticed that Jim Williams recommended LT1352 for filtering applications (which I need) since its input bias current is low (for BJT opamps) while LT1358 with high bias current is not suitabe there.....

 Or any better suggestion other than LT1352 for filters?_

 

What kind of filtering?


  Quote:


 BTW, any opamp has interesting quality for mid and bass? 
 

Definitely the LT1469 for me, but also the LT1355, not to mention the LT1358 
	

	
	
		
		

		
			






 I love the LT1355... without direct comparisons, it seems to be the most precise of the 13xx series. If you look at the harmonic distortion, it does have the least amount especially at high frequency.


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## ROBSCIX

You just reminded me, there are so many more units I would like to get.


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## Pluto2

hopeless;5821160 said:
			
		

> What kind of filtering?
> 
> Hi pass and lo pass for a speaker system....
> 
> ...


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## hopeless

LT1469 or OPA2211 or one of the LME's for filtering,

 and LT1358 or LT1364 for buffering.


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## Pluto2

Thanks hopeless,
 But what happened to your beloved LT1355?
 And you don't like lt1352, why? Is opa2211 good for filtering, I thought the input current was not low, yes? ..


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## Pluto2

Thanks hopeless,
 But what happened to your beloved LT1355?
 And you don't like lt1352, why? Is opa2211 good for filtering, I thought the input current was not low, yes? ..


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## hopeless

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Thanks hopeless,
 But what happened to your beloved LT1355?
 And you don't like lt1352, why? Is opa2211 good for filtering, I thought the input current was not low, yes? .._

 

I'm listening to my DAC with the LT1355 still inside... Sounds great. 


 I didn't suggest it just because the higher quiescent current of the LT1358 and LT1364 may make them more suitable for driving heavy loads well (just in case).

 While for filtering the LT1355 may not have a input current low enough. Yes the OPA2211 has low input bias current, equal to that of the LT1352. The LT1469 has it even lower, as low as the LME's.


 I don't recommend the LT1352 because comparing the various steps of 'speed reduction' by lowering the internal bias levels, i.e. comparing the graphs in the datasheets 
	

	
	
		
		

		
		
	


	




 , it is obvious that the LT1352 doesn't have a quiescent current that allows for the best distortion performance of this series's topology. It looks like the LT1357/8 and LT1354/5 are the sweet spot (for line level applications at least). I prefer the neutrality of the LT1355 to the slight exhuberance of the LT1358.


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## 12Bass

Although it has been some time since I listened to it, I seem to recall finding the LT1358 fairly clear yet somewhat thin sounding and preferring the perhaps more neutral LM/LME parts from National (and later preferring the OPA211). Haven't tried the LT1355. The OPA2211A should be arriving shortly, so hopefully I'll have some impressions soon.


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## hopeless

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Although it has been some time since I listened to it, I seem to recall finding the LT1358 fairly clear yet somewhat thin sounding and preferring the perhaps more neutral LM/LME parts from National (and later preferring the OPA211). Haven't tried the LT1355. The OPA2211A should be arriving shortly, so hopefully I'll have some impressions soon._

 

Depends on your system and your preferences for tonality. Changing the LM4562 with the LT1355 I heard Leonard Cohen's voice fuller (and smoother) rather than thinner. It (and the LT1358) does have a more open sound than the LM/LME that may make it sound thinner with records that are pushing the mid-treble forward by themselves. 

 The LT1355 from memory should be cleaner than the LT1358, because the latter has a slightly accentuated midbass (at least @ 12V).


 Regarding the OPA211, it's fine sounding except that it has a peculiar coloration that makes vocals (especially female) sound a bit too creamy. I'll try the OPA2211 as well, and compare with the LT1355, as soon as those adapters arrive...



 EDIT- also the LM/LME's have, IMO, an overly smooth upper midrange that may sound audiophile perhaps but IMO is not quite right. On the contrary the treble is a bit spiky. Audiophile indeed.


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## Ansh

A beginner's question
	

	
	
		
		

		
		
	


	



 Is 843SQ/746SQ one of the best(or at most expensive) OPAMPs of DIP8?


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## SpudHarris

^ AD843 is definately a contender in my book. AD744's (on OBCA adapters) are another contender. I also like the AD797's and starting to get into most of the better LT chips lately.

 Having a P3 and P3+ gives me plenty of options for rolling but like most of you guys I have my favourites.


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## Pluto2

My friend has tried quite a number of opamps and his favorite is AD843sq for his Promitheus DAC....

 I don't have a feel if an input bias of 60nA (175nA max) for opa2211 is going to hurt the filter...while LT1352 is 20nA(50nA) and LME49860 is 10nA(70 nA)...., otherwise using opa2211 in that area would be quite tempting 
	

	
	
		
		

		
		
	


	




 Maybe it's all system dependent? I did replace a LM4562 with LT1358. I think LT1358 has better clarity and spatial resolution and sweeter voice....


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## hopeless

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Maybe it's all system dependent? I did replace a LM4562 with LT1358. I think LT1358 has better clarity and spatial resolution and sweeter voice....
	

	
	
		
		

		
		
	


	


_

 

I definitely don't disagree. 
	

	
	
		
		

		
		
	


	





 BTW the LT1355 is wonderful also with Jolie Holland's latest "The living and the dead", another familiar record. That it sounds completely different (including tonality) from the former record I'd been listening to, is proof of the LT1355 transparency & coherence.


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## Pluto2

Look forward to your comments on opa2211 : )


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## Pluto2

12Bass, what's your impression on LT1358 vsLT1352?


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## Bonthouse

Guys, I need some help because I just can't find any good info on the matter at hand..
 I'm looking for a detaild, yet warm single channel SOIC opamp. It's for my Corda Move.
 I had the AD8610's installed, then I replaced them with the LME49710's.
 It is a serious upgrade in SQ, but a bit too cold for my taste.

 Any recommendations?


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## SpudHarris

I'd go with AD744's (OBCA) or the AD843's.

 Knowing you Sam, I think you would get a kick out of making up the OBCA adapters for the 744's.


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## hopeless

Quote:


  Originally Posted by *Bonthouse* /img/forum/go_quote.gif 
_Guys, I need some help because I just can't find any good info on the matter at hand..
 I'm looking for a detaild, yet warm single channel SOIC opamp. It's for my Corda Move.
 I had the AD8610's installed, then I replaced them with the LME49710's.
 It is a serious upgrade in SQ, but a bit too cold for my taste.

 Any recommendations?_

 

Try the OPA228UA, if the gain of the circuit is about 5 or more (or if it has a gain setting and you don't mind keeping it high). I think it has what you want.


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## hopeless

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I'd go with AD744's (OBCA) or the AD843's.

 Knowing you Sam, I think you would get a kick out of making up the OBCA adapters for the 744's._

 

Err sorry... The AD744 (especially if you bypass its output stage) surely can't drive headphones and the AD843 doesn't exist SOIC.


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## SpudHarris

Er sorry...... but I'm using them in my P3+ driving headphones. I didn't pay too much attention to the SOIC in Sam's post as I did not understand why it would need to be SOIC? Doesn't the move use DIP sockets? 

 Do you actually have the AD744's or are all your OpAmps Linear Technology?? 
	

	
	
		
		

		
		
	


	




 we can all read data sheets but I like to hear them so don't comment unless I've actually used them.


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## BobMcN

My CD player (an Ayre CX7e) uses the AD844's. Don't know if they can drive headphones either, but they do sound warm and inviting with plenty of detail. The music just flows. Very analogue like presentation with kick ass bass extension and drive.

 Bob


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## hopeless

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Er sorry...... but I'm using them in my P3+ driving headphones. I didn't pay too much attention to the SOIC in Sam's post as I did not understand why it would need to be SOIC? Doesn't the move use DIP sockets? 

 Do you actually have the AD744's or are all your OpAmps Linear Technology?? 
	

	
	
		
		

		
		
	


	




 we can all read data sheets but I like to hear them so don't comment unless I've actually used them._

 

You're using them in your P3+ because there's a buffer in between the opamp and the headphones...

 (though the AD843 would drive them well also alone)



 And yep the Move uses SOIC opamps because the AD8610 only exists as SOIC.


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## SpudHarris

You don't say...... but the SOIC's are on a DIP adapter No?


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## Bonthouse

Nope, this is the room I have to play with


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## SpudHarris

Got ya, my bad, thanks Sam.....Understand why SOIC. Not the sort of job you want to be doing often though. Also forget about the adapters, the ones I make are on DIP sockets also.


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## Bonthouse

Very true. But with enough flux, a 225 degrees celsius soldering tip and a steady hand it's possible to do it enough times.
 But lets say I want to improve the bass just a little, but keep this opamp. Would different signal caps do the trick? I currently have 3 Elna Cerafine 10v 220uF's installed. 
 Would replacing them with Elna Silmic II's change the sound enough?


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## hopeless

Quote:


  Originally Posted by *BobMcN* /img/forum/go_quote.gif 
_My CD player (an Ayre CX7e) uses the AD844's. Don't know if they can drive headphones either, but they do sound warm and inviting with plenty of detail. The music just flows. Very analogue like presentation with kick ass bass extension and drive.

 Bob_

 

Thanks for the information. That is potentially interesting for a CMOY that supports bipolar opamps (such as mine 
	

	
	
		
		

		
		
	


	




 ), except that it isn't clear if it's stable or not with any gain of less than +10. While it's specified as stable with G= -1 or more. Perhaps I'll try it if I can find it.

 However, it doesn't seem to exist as SOIC, either. So not for the Corda Move.


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## hopeless

Quote:


  Originally Posted by *Bonthouse* /img/forum/go_quote.gif 
_Very true. But with enough flux, a 225 degrees celsius soldering tip and a steady hand it's possible to do it enough times.
 But lets say I want to improve the bass just a little, but keep this opamp. Would different signal caps do the trick? I currently have 3 Elna Cerafine 10v 220uF's installed. 
 Would replacing them with Elna Silmic II's change the sound enough?_

 

Hmm, not quite sure but I don't think you can change the balance much by just changing the reservoir caps. It would be a different thing if they weren't there at all originally.

 I would change the opamps with OPA228UA's. But since that's always a risk with SMD opamps... be it your choice entirely.


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## ROBSCIX

What are some favorite opamps for I/V?


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## FallenAngel

Really should state the PURPOSE of the opamp you are recommending.

 I/V - I've heard great things of the OPA1632 for I/V - TwistedPearAudio uses it and I must admit, I love their stuff.

 Driving headphones directly - AD8397 is pretty damn good and rail-rail. AD825 is really good for that as well, but it doesn't swing rail-rail and runs nicer from 12V+.

 Behind a buffer, I like AD825, AD8065, LME49710 among with a few others.


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## hopeless

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Really should state the PURPOSE of the opamp you are recommending.

 I/V - I've heard great things of the OPA1632 for I/V - TwistedPearAudio uses it and I must admit, I love their stuff._

 

For I/V it's much simpler to use the LT1468. I've heard great things about it for _THIS_






 purpose. Otherwise, I'd try the OPA827.


  Quote:


 Driving headphones directly - AD8397 is pretty damn good and rail-rail. 
 

Been using it both at 12V and at 24V; sounded better at 24V, but I still preferred 2x AD845KN and later 2x OPA228P to it. That's with my 32 ohm phones, HD238 and HD485.

 The AD8397 is powerful but: 1) lacks some body on vocals despite its current 2) sounds dryish in the mids 3) lacks a bit of color. At 24V it was less dry and a bit more natural.

  Quote:


 Behind a buffer, I like AD825, AD8065, LME49710 among with a few others. 
 

Myself, I really disliked the AD8066 a lot when I tried it (yup, behind a buffer). It had rough mids and was white sounding.

 Instead, I do like the LME49710 quite a bit (despite my criticism to it 
	

	
	
		
		

		
		
	


	




 ) inside my DIYEDEN SVDAC05. Nonetheless, the LT1355 sounds just as good (if slightly different) inside the other DAC and at a lower supply voltage. The same is true of the LT1358 I'd used before.


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## Pluto2

Hi hopeless,

 Decided to try out the LT1469 & LT1358 combination, and about to order a bunch of LT1469s for the filters (too bad only SOIC is available at digikey
	

	
	
		
		

		
		
	


	




). 

 Will swap around later with the LMEs I have.
 Thanks for the advice


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## leeperry

so I like the uber-transparent and pretty much distortion-free upper spectrum on the 49720NA, but the bass is a bit too hollow and distant to my taste....what would be a good prescription(in DIP8 or TO99 if any possible) for I/V you mad professors? 
	

	
	
		
		

		
		
	


	




 thanks!


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## FallenAngel

Yuk, hated the OPA228 at 9-32V, unbearable highs without buffer, just as bad behind one.

 Haven't tried LT1468 or AD827.

 Don't know much about all of these LT chips, not much info on them (except the insane ravings of _andrea_).

 I also really have to say the LME49710 is nice, but certainly not "very good". It's a good chip when restricted to certain voltages (which is why I use it behind a buffer in my portable amp), but I definitely wouldn't drive headphones with it, nor would I put it into something other than a line driver when I had absolutely no choice - such as TwistedPearAudio IVY).


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## hopeless

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Yuk, hated the OPA228 at 9-32V, unbearable highs without buffer, just as bad behind one.

 Haven't tried LT1468 or AD827.

 Don't know much about all of these LT chips, not much info on them (except the insane ravings of andrea)._

 

Don't know... inside my (evolved 
	

	
	
		
		

		
		
	


	




 ) CMOY the OPA228 at 24V sounds great and treble is very well controlled. (I don't use Grado's...just in case)


 Regarding LT opamps... yes I like them. Shouldn't I? They're a sweet spot between the strengths & weaknesses of the other offerings I know.


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## hopeless

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_I also really have to say the LME49710 is nice, but certainly not "very good". It's a good chip when restricted to certain voltages (which is why I use it behind a buffer in my portable amp), but I definitely wouldn't drive headphones with it, nor would I put it into something other than a line driver when I had absolutely no choice - such as TwistedPearAudio IVY)._

 

Still inside the SVDAC05 it performed better than: TI NE5534, LT1028ACN8, AD797, LT1363, OPA211, OPA827, when _living with_ a certain sound was concerned. That's why I removed the sockets and soldered it in.

 Have you tried the TO99 version?


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## hopeless

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Hi hopeless,

 Decided to try out the LT1469 & LT1358 combination, and about to order a bunch of LT1469s for the filters (too bad only SOIC is available at digikey
	

	
	
		
		

		
		
	


	




). 

 Will swap around later with the LMEs I have.
 Thanks for the advice 
	

	
	
		
		

		
		
	


	


_

 

I think you'll love it. Let us know how you find the LT1469 to be in your application.


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## FallenAngel

If you got the AD797, you're something special, it's a VERY hard opamp to get to work. OPA211 is no slouch either, also a terrible bipolar to stabilize.

 Since you're asking about TO99 package vs DIP8, hi _Andrea_


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## hopeless

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_If you got the AD797, you're something special, it's a VERY hard opamp to get to work. OPA211 is no slouch either, also a terrible bipolar to stabilize.

 Since you're asking about TO99 package vs DIP8, hi Andrea



_

 

The AD797 worked just fine, didn't get hot or anything. It sounded fine, tonally pleasing, with solid fast bass, but it was a little too dry in the midrange, which is common to all of the AD chips I know of (have yet to try the AD8599).


 The OPA211 (tough to stabilize!?) was my other favorite for the SVDAC05, thus I'll try the OPA2211 very soon in the modified Super Pro where the LT1355 is sounding so good that I may also keep it forever (but I guess I won't 
	

	
	
		
		

		
		
	


	




).


 Regarding the OPA228, I have to agree with majkel regarding its ability to spatially separate instruments better than most opamps. Even in a CMOY. Will try 2 of them inside the Super Pro next.

 Did you try 2x AD845KN unbuffered? It drives headphones very well, too, with less dryness & more musicality than the other AD's I tried in the CMOY (including AD8620 and AD797).


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## Pluto2

hopeless your findings on LT1355 vs LT1358 conincides with someone else 's I found on web (a Japansese site)
	

	
	
		
		

		
		
	


	




 Should I also get the LT1355s (4 pc).....hmmm, wondered the difference would be just subtle....worth to get them....
	

	
	
		
		

		
		
	


	




 How would you say about LT1356 (vs the above chips)? The gentleman found it a nice match with LT1469 in a preamp....


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## hopeless

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_hopeless your findings on LT1355 vs LT1358 conincides with someone else 's I found on web (a Japansese site)
	

	
	
		
		

		
		
	


	




 Should I also get the LT1355s (4 pc).....hmmm, wondered the difference would be just subtle....worth to get them....
	

	
	
		
		

		
		
	


	




 How would you say about LT1356 (vs the above chips)? The gentleman found it a nice match with LT1469 in a preamp....
	

	
	
		
		

		
		
	


	


_

 

LOL, funny! 


 The LT1356 is the quad version of the dual LT1355, no more no less.

 Sooo.... LT1355 and LT1469 should make a nice match.


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## hopeless

I'm tooo curious about the OPA2822 (just received 5 of them) in my 12V DAC. It might turn out as the ideal solution, even. Adapters pleaaase coooome...


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## Pluto2

Quote:


  Originally Posted by *hopeless* /img/forum/go_quote.gif 
_LOL, funny! 


 The LT1356 is the quad version of the dual LT1355, no more no less.

 Sooo.... LT1355 and LT1469 should make a nice match. 
	

	
	
		
		

		
		
	


	


_

 

Oooops, typo, it should have been LT1346, rather than LT1356....


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## Bonthouse

Another question from me; what's the difference between the 'AD797BRZ' , the 'AD797BRZ-REEL' and the 'AD797BRZ-REEL7' ?
 I seriously can't find the differences..


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## majkel

Bunch packaging method only. Does not apply to the chip directly.


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## SpudHarris

I've only just started using Linear Technology OpAmps but have to say that I do like some a lot. The 1357's are real nice and I have an LT1124 and 2 x 1468's coming today from Farnell.

 I will roll them this evening in my P3+ and post back.


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## SpudHarris

The LT1124 was recommended by a guy who's been working with ibasso on the P3 OEM project & he really knows his stuff. I was having trouble with my favourite OpAmps (OPA637's) in my P3+ and he suggested this as an alternative as it is supposedly very fast and detailed. I'm looking forward to testing it tonight.


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## Pluto2

Quote:
 Originally Posted by Pluto2 
 Oooops, typo, it should have been LT1346, rather than LT1356.... 

 LT1346 does not exist as an opamp - thus it must have been LT1356 indeed. 

 ---

 oh no, too many typos, I meant LT1364 
	

	
	
		
		

		
			





 Never mind hehe, 
	

	
	
		
		

		
		
	


	




 Spoke to Jim Williams today......looks like no problem using LT1358 at all through out the circuit, including the LPF and HPF.....


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## supertramp

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Quote:
 Originally Posted by Pluto2 
 Oooops, typo, it should have been LT1346, rather than LT1356.... 

 LT1346 does not exist as an opamp - thus it must have been LT1356 indeed. 

 ---

 oh no, too many typos, I meant LT1364 
	

	
	
		
		

		
		
	


	




 Never mind hehe, 
	

	
	
		
		

		
		
	


	




 Spoke to Jim Williams today......looks like no problem using LT1358 at all through out the circuit, including the LPF and HPF.....
	

	
	
		
		

		
		
	


	


_

 

IMO LT1355 (or LT1358) + LT1469 is a better match than LT1364 + LT1469. I look for tonal neutrality above all.


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## SpudHarris

Well I have been doing some initial testing the LT1124 and have to say I am really amazed that people don't mention it more. It is indeed very detailed and lightning fast, I can't say it's a neutral sounding OpAmp as it does have a colouration of sorts that makes it an interesting listen. It's hard to put into words but it's musical and I like it a lot. I will keep it in my P3+ and try some different combo's of buffers and V/G OpAmps. The 1469's will have to wait until I have got used to the 1124, if my initial findings are anything to go by the 1469's may be gathering dust for a while yet.


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## supertramp

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well I have been doing some initial testing the LT1124 and have to say I am really amazed that people don't mention it more. It is indeed very detailed and lightning fast, I can't say it's a neutral sounding OpAmp as it does have a colouration of sorts that makes it an interesting listen. It's hard to put into words but it's musical and I like it a lot. I will keep it in my P3+ and try some different combo's of buffers and V/G OpAmps. The 1469's will have to wait until I have got used to the 1124, if my initial findings are anything to go by the 1469's may be gathering dust for a while yet._

 

Interesting. Even though the LT1469 certainly won't be less fast & detailed.


 I will have to try the LT1124. I know (from my very unique numerical thory 
	

	
	
		
		

		
		
	


	




 ) that it will work well as far as tonal balance is concerned with the CS4398 DAC. 

 I thought of trying the NJM 2114 (used in Arcam CDPs of the latest generation) too, but maybe this is worth giving the precedence. 
	

	
	
		
		

		
		
	


	





 P.S. Also try the LT1355, which altogether I prefer to the LT1469... even if the latter can be more impressive with certain records (but a little disappointing with others). The LT1355 just sounds right in my DAC. Not that easy to sound so right.


----------



## Pluto2

noticed that LT1355 displays less overshoot but has longer settling time than LT1358, what does it translate to in sonic characteristics? 

 JW did mention LT1469 is an old chip....


----------



## exhausted

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_noticed that LT1355 displays less overshoot but has longer settling time than LT1358, what does it translate to in sonic characteristics? 

 JW did mention LT1469 is an old chip...._

 

Didn't know it was "old". What else did he say about it?


 The settling time of the LT1355 is still quite fast compared to the likes of the LME49xxx and the other "audio opamps".



 Just tried the OPA211AID inside the Super Pro...

 Well... Very controlled bass, milky mids, clear indeed. Pity that it's a bit cool tonally compared to the LT1355. They both have their advantages. For now I'll keep the 2x OPA211...

 May it be that the AID sounds better than the ID? Formerly I thought that the OPA211 was more colored. Perhaps it were the +/-15V instead of 12. Or that the ID sounds more colored


----------



## exhausted

I have replaced (in the Super Pro of course) the 330nF Wima MKS2 with a 33uF tantalum, bypassing the 680uF Rubycon ZL, in order to have the most speed in energy delivery to the opamp.

 Soo the OPA211 are given the best environment to perform like they can. And they perform. 
	

	
	
		
		

		
		
	


	





 I think that in the future I'll make a test and compare LT1354 x2 to LT1357 x2 to OPA211 x2. I guess that it's worth limiting my choice to one of these.


----------



## ROBSCIX

I have heard that OPA211's were very good. I soldered up some modules the other night but have yet to test them.


----------



## exhausted

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I have heard that OPA211's were very good. I soldered up some modules the other night but have yet to test them._

 

They are... except for a little lack of the vivid tonal color of the LT1355 or LT1358. 
	

	
	
		
		

		
		
	


	




 I will see if I can live with them or... I'll have to go back. 
	

	
	
		
		

		
		
	


	





 BTW, the OPA211 is not apparently more transparent than the LT1355... just different.


----------



## leeperry

I think the rules of this forum encourage arguments...so here I come 
	

	
	
		
		

		
		
	


	




 I've asked several highly skilled sound engineers(the kind that gives lectures about audio and works at building highly accurate measurement tools), and they all told me that :
 -yes, there's many op-amps that give a clearer SQ than the 5532
 -*BUT* most records have literally gone through hundreds of 5532/5534...and most of them have basically been mixed on these, and are aimed at being listened to on these 
	

	
	
		
		

		
		
	


	



 -you can embelish what's on the record, but in the end the 5532 just gets it "right". maybe that's why Lynx puts them on all their top-end cards? the ppl I'm talking about only use cards from this company.

 I think many ppl will agree that the 4562 has very clear trebles, but the low end bass response lacks. and same for the LT1469 apparently?

 anyway, even in these measurements the 4562 beats the 5532 : RMAA Testing of Audio IC Op Amps

 but is music about distortion-free trebles and tame bass? isn't it asking for troubles to search for something undiserable to begin with 
	

	
	
		
		

		
		
	


	




 I've read some ppl saying that whatever op-amp they were trying "worked" on most songs, but not on all....maybe that's because the ultimate op-amp that makes everything so much better...simply doesn't exist?

 what do you say about the JRC2114D for I/V? it's a slightly improved 5532 
	

	
	
		
		

		
		
	


	




 PS: that guy who keeps getting banned and talks about numerology in op-amps is simply out of this world 
	

	
	
		
		

		
		
	


	




 he should run a team w/ Patrick82, how about ESD wrapped op-amps w/ "compatible" numbers


----------



## ROBSCIX

Quote:


  Originally Posted by *exhausted* /img/forum/go_quote.gif 
_They are... except for a little lack of the vivid tonal color of the LT1355 or LT1358. 
	

	
	
		
		

		
		
	


	




 I will see if I can live with them or... I'll have to go back. 
	

	
	
		
		

		
		
	


	





 BTW, the OPA211 is not apparently more transparent than the LT1355... just different._

 

I will have to do some more in depth testing with the OPA211's, and some LT's. I have the ones you mentioned but there are a few more I have been looking at.
 Just installed ExpressPCB, gonna start putting together some projects.
	

	
	
		
		

		
		
	


	



 I have been doing a great deal of testing and buiding of various oapmps modules latley now I need to set a day aside to sit down and listen to them.


----------



## les_garten

Quote:


  Originally Posted by *pacemaker* /img/forum/go_quote.gif 
_Well, I can say that the OPA211 is not the ideal opamp.


 Between 2x OPA211 and one LT1355, the latter was more musical and engaging for my ears and the music I listen to. The OPA211 is a little bit colorless... 

 Maybe in the Super Pro I'll put 2x LT1028CS8, which had sounded great the last time I used them (here)._

 


 You're like a big wad of GUM that you can't get off your shoe!

 .


----------



## SpudHarris

Quote:


  Originally Posted by *superiore* /img/forum/go_quote.gif 
_These are the sort of people that make it impossible for those like me to be here.

 Let me quote majkel... No I can't. His post has been removed too.


 There's nothing right with this forum, no honesty or transparency to be found, neither on the side of the "population" nor on that of the "power".


 Only such ridiculous humans as "les_garden" are stupid enough to feel good here. The others are just desperate for lack of life or places to go._

 

I'm not sure what's going on here?? 

 I understand that on occasions people disagree but it seems that the grudges people hold seem to bleed into other threads and that's when the rot sets in. I WAS enjoying hearing about other peoples experiences and thoughts regards this thread, don't agree with some of it, but as I always say what ever you hear is a person thing and always subjective. Can we just move along now?

 What's the story with Majkel? He/She and I were having a great chat and now their posts are removed. My posts/replies don't make a great deal of sense since Majkels replies/posts were removed.


----------



## SpudHarris

Quote:


  Originally Posted by *superiore* /img/forum/go_quote.gif 
_We just can't touch them. While they do whatever they want with us -- like change the inclination of an argument by selectively removing posts, or simply delete users.

 Don't be naive._

 

This coming from someone with 3 posts!

 I'm trying to get the thread moving again, I suggest you deal with your paranoia buddy and move to another thread if you've nothing to say regarding the OP.


----------



## leeperry

how about the OPA2111? I'm only reading raving reviews about it, they just popped in the mail...will try them later, even though I'm really in love w/ the 4562NA sound...more "hifi" than the 49720 as this site puts it :
.: Audiocom International :. Modifications : Marantz CD-63 KI Signature

  Quote:


 This op-amp is essentially the same as the LM4562 but on A/B tests we have found the LME49720 is less “Hi-Fi” sounding. 
 

PS: you complain about the mods in here? go to the hydrogen-audio forum, these ppl are nutcases..


----------



## SpudHarris

I bought the single (OPA211) version so I could run them in Class A, it will be different in different circuits and with different phones but in my P3+ I struggled to tame the bass. That said, it was quality bass, just too much for my liking. As for it's other qualities? well as everyone says it's a fine OpAmp and not much to dislike really.


----------



## leeperry

I've always been under the impression that the 4562NA would blow pretty much any other op-amp out of the water(except for the discrete ones of course)...can you get the same HUGE soundstage and distortion-free trebles on another chip? anyway, I'll be soon to find out 
	

	
	
		
		

		
			





 Ideally I'd like to have a 4562NA w/ a tad more low end bass...then I'd call it a day


----------



## 12Bass

OPA2211A is about to be tested. Based upon experience with OPA211, I suspect that I'll prefer it to LM4562/LME49720.


----------



## les_garten

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I'm not sure what's going on here?? 

 I understand that on occasions people disagree but it seems that the grudges people hold seem to bleed into other threads and that's when the rot sets in. I WAS enjoying hearing about other peoples experiences and thoughts regards this thread, don't agree with some of it, but as I always say what ever you hear is a person thing and always subjective. Can we just move along now?

 What's the story with Majkel? He/She and I were having a great chat and now their posts are removed. My posts/replies don't make a great deal of sense since Majkels replies/posts were removed._

 

Here's who Andrea is:

http://www.head-fi.org/forums/f11/at...t-life-288523/

 His problem is he bleeds over into lots of threads and becomes disruptive. Very disruptive sometimes. He has been banned 100's of times in about 5 years and is a truly Pathetic individual. Don't encourage this pathetic lump.

 .


----------



## 12Bass

So, perhaps not surprisingly, OPA2211A sounds very similar to 2 x OPA211 on a BrownDog 020302 adapter. Compared to LM4562, the OPA2211A sounds more open, yet not harsh, in the highs, with a nice, dare I say, "natural" roundness and warmth, while the LM4562 sounds more sterile and flat. Or maybe the OPA2211A is colored in euphonic way..... In any case, I like it.


----------



## 12Bass

Also gave the LT1358 a quick audition... and it didn't impress me particularly. Not bad, just not much different than the LM4562, and not as good as the OPA2211A, IMO, though my K702s are out of commission at the moment, which necessitates using my K240Ms, so that might obscure some of the nuances. I'll try to rig up 2 x AD797 in the near future.


----------



## LingLing1337

Just tossed my NE5532 for a THS4032CD... I'm not even curious about other opamps now.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_So, perhaps not surprisingly, OPA2211A sounds very similar to 2 x OPA211 on a BrownDog 020302 adapter. Compared to LM4562, the OPA2211A sounds more open, yet not harsh, in the highs, with a nice, dare I say, "natural" roundness and warmth, while the LM4562 sounds more sterile and flat. Or maybe the OPA2211A is colored in euphonic way..... In any case, I like it._

 

 I just built 2 -211 modules (opamps and brown dogs) but have had little time to test them. what I heard though I liked. I may have to check the 2211's...so many surface mount chips.


----------



## les_garten

Quote:


  Originally Posted by *groan* /img/forum/go_quote.gif 
_Well I knew you had given a listen to the LT1358 and weren't impressed...

 Where was it? Sure it was stable (it's not a regular audio opamp, it's fast)? 


 That said, I do prefer the LT1355 to the LT1358. To me there's a slight muddiness in the latter that is not in the former.


 Having said all that, the OPA211 is growing on me... But I still miss the vivid tonal color of the LT1355. It just gave Tom Waits or Lucinda Williams the right 'intensity'. I surey prefer it for my DAC to the LM4562, which to me is nice but not excellent in anything, neither resolution nor natural color.


 Finally, the *TLE2062* is making my 24V CMOY fly... Someone else should take advantage of it._

 

You've been reported...


----------



## majkel

I rate the LME49860 higher than the THS4032. They are similar but the last one simplifies tonality a small bit. I still think the LME49860 is my favorite dual op-amp. Not so thick and smeary as the LM4562 and not so bland as the LME49720.


----------



## 12Bass

While clear and authoritative sounding, I found the THS4032 missing some body in the midrange - it sounded a bit artificial to my ears. The OPA2211A, on the other hand, sounds clear, yet warm throughout the audio band, IMO.


----------



## leeperry

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I rate the LME49860 higher than the THS4032. They are similar but the last one simplifies tonality a small bit. I still think the LME49860 is my favorite dual op-amp. Not so thick and smeary as the LM4562 and not so bland as the LME49720._

 

interesting! I would indeed love a mix between the 4562 and 49720...w/ a tad more low end bass on top.

 in my tests, the 49720NA had very clear top trebles, but the bass really lacked...and the 4562NA had very clear bass(not quite perfect though, but very much acceptable) but the top trebles sounded muffled...yet clear, but just not as clear the 49720NA.

 the 49720HA had tons of bass, but the top trebles sounded muffled as well.

 so now you tell me about the 49860? I thought these were the high voltage version of the 49720?

 anyway, I will try the OPA2111 later today, hopefully it'll be my golden ticket...everyone praises it : 
Little Dot MK1 opamp rolling - Head-Fi: Covering Headphones, Earphones and Portable Audio
REVIEW: MINI USB DAC, wad a lousy name


----------



## 12Bass

At the risk of repeating myself, I suggest trying the OPA2211A. Somehow I'm doubtful of older chips like the OPA2107, OPA2111, etc....


----------



## leeperry

yeah, thanks, I saw you mentioning this one...but it's only available in funky packages?! : Precision Amplifiers - Low Noise - OPA2211A - TI.com

 and I read you didn't like the OP275? AD advised me to try it.

 anyway, I love the clear trebles on the 49720NA, maybe I'll just add some crazy EQ in the low end to make it give


----------



## Cynips

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I rate the LME49860 higher than the THS4032. They are similar but the last one simplifies tonality a small bit. I still think the LME49860 is my favorite dual op-amp. Not so thick and smeary as the LM4562 and not so bland as the LME49720._

 

Are you talking 49720NA here? And in what setup have you tried out these opamps?


 BTW, I got my LT1358's in the mail today, but I still want to get a pair of adapters for the HA's. Anyone know if buying from audioupgrades.co.uk is the cheapest way of getting hold of TO-99 to 8 pin DIP adapters when you, as I do, live in Sweden? As good as the HA's sound on my setup I find it more than likely that I will want to reinstall them after checking out other opamps. If nothing else for the sake of further comparison.


----------



## SpudHarris

You will probably get them here. Audioupgardes distribute the Cimarron Stuff so buying direct could possibly be cheaper.


----------



## 12Bass

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_yeah, thanks, I saw you mentioning this one...but it's only available in funky packages?! : Precision Amplifiers - Low Noise - OPA2211A - TI.com

 and I read you didn't like the OP275? AD advised me to try it.

 anyway, I love the clear trebles on the 49720NA, maybe I'll just add some crazy EQ in the low end to make it give 
	

	
	
		
		

		
		
	


	


_

 

IMO, the OPA2211A is a bit clearer than the LME part, and more organic-sounding too. Many of the modern high performance opamps are not available in DIP, so most of us employ SOIC -> DIP adapters. OP275 was well-regarded in the 90s, but not so much today.


----------



## majkel

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_Are you talking 49720NA here? And in what setup have you tried out these opamps?_

 

No, the MA version. The platform was the DAC used for the review in my signature. Trying the old school OP275 is a waste of time and money.


----------



## SpudHarris

Just found out some 49710's in my ''odds and sods'' chips. I only ever tried them in a cmoy and that was quite some time ago (before I got any quality amps). If my memory serves me well I found them to be a little sterile / metalic, but like I said that wasn't in a quality circuit.

 I'm going to give them a try in the P3+ this evening.


----------



## leeperry

oh my, the bass is awesome on the 2111 
	

	
	
		
		

		
		
	


	




 nothing I've ever heard from the LM/LME serie 
	

	
	
		
		

		
		
	


	




 and the SS is also pretty damn wide! sound's very detailed, and the spatial placement is far less messy than on the LM/LME. you can almost pin-point their respective locations.

 hopefully its sound signature won't change after burn-in, so far I <3 it...even the trebles are very detailed and not harsh like the LM/LME...it just sounds very impressive so far!

 PS: I'm gonna buy a Chinese t-amp that's got a 4580, and put one of these babies instead...my dub plates are not gonna be smokin'


----------



## majkel

I've got the OPA2111KP in my repository but I could let it go, as well as many other op-amps. It's surely better than the similar OPA2107.


----------



## leeperry

anyway, one of my test tracks is "The Stranglers - Golden Brown"...and it sounds far more natural that it ever did on the LM/LME, it's pretty clear that they were pushing the top mids and made the harpsichord sound wonky as hell.


----------



## SpudHarris

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I've got the OPA2111KP in my repository but I could let it go, as well as many other op-amps. It's surely better than the similar OPA2107._

 

The OPA2111 is the dual version of the OPA211 isn't it? Just goes to show how subjective this subject is because out of the OPA211 and OPA2107 I would take the OPA2107 every time.


----------



## majkel

No, OPA2111 = 2x OPA111.


----------



## SpudHarris

Ah..not tried the OPA111 or OPA2111 yet. Thanks.

 Wow they're quite expensive, especially the ''KP''. How much do you want for it?


----------



## 12Bass

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_The OPA2111 is the dual version of the OPA211 isn't it? Just goes to show how subjective this subject is because out of the OPA211 and OPA2107 I would take the OPA2107 every time._

 

Not me..... 

 Found the OPA2107 lacking, compressed or something, from what I recall - fairly disappointed with it especially considering the high cost and all of the accolades. IMO, the more modern OPA211/2211A are in a different league - clearer, lower distortion, and more natural-sounding. Not sure if I'd even consider the OPA2107 better than the OPA2132. I'd take OP827 over those two if I needed FET input.


----------



## SpudHarris

Like I said ''Subjective''.

 No OPA2211 on Farnell? But I wouldn't mind a look at the OPA2111KP. They have the OPA111's but they are TO-99 only and VERY expensive.

 Anyone want to part with a 2111KP - majkel??


----------



## leeperry

it takes time to get used to the "neutral" mids on the 2111, the LM/LME were putting it up the roof in comparison 
	

	
	
		
		

		
		
	


	




 but man, the bass sounds so friggin' good 
	

	
	
		
		

		
		
	


	




 well TI gives away the 2111 for 100% free....except if you have high level ethics, I don't see any problem here...and they ship fast as hell!


----------



## SpudHarris

I don't have too much trouble with ethics if they are 100% free. Could you PM me on how? Cheers Leeperry!


----------



## leeperry

it's easy : signup on TI.com, add them to your "samples cart", follow the on-screen infos...and in 3/4 days a FEDEX truck will pop up in front of your house, et voila 
	

	
	
		
		

		
			





 I mostly listen to bass heavy music(70's reggae/deep funk), and the bass is just jaw dropping on these things...it's not bloated, it's not tame, it's not overblown...it just sounds too good 
	

	
	
		
		

		
		
	


	




 I think that's because it doesn't have that 4K spike like on the 4562/49720...it doesn't try to cheat you w/ some "audiophile" mids, so as a matter of facts the bass is more natural...and so are the top trebles as well.
 but I can see how many ppl will find a "neutral" presentation boring...I find it quite natural, very clear soundstage....and that bass!


----------



## Bonthouse

You can get samples trough their site. Bummer they don't do the OPA111 for free. I'd love to try that one in my Move!
 Spud, got any recommendations from LT?


----------



## Pluto2

Hi Maijkel,
 What are your comments on LME49860, LT1358, and OPA2211 please?


----------



## Cynips

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I'm still waiting on my LT1358 samples, LT seems less willing to give op-amps away 
	

	
	
		
		

		
		
	


	


_

 

Why do you say that? When did you order yours? LT confirmed my order on the 9th and I got part of it (the two LT1358IN ones) today already.


----------



## leeperry

oops, my bad...you're right! they didn't like my gmail account, and I couldn't remember which login I gave them...they shipped 3 days ago 
	

	
	
		
		

		
		
	


	




 how do they ship btw? Fedex, USPS?

 I'm still not used to not having the 4562 screaming mids shouting at me, but so far I still like that 2111...if that's the best bass I can get, then I'll be perfectly happy w/ it 
	

	
	
		
		

		
		
	


	




 and does AD give samples away? you either have to talk to their sales reps or buy them in bulk order? 50 pieces will be a tad too much..


----------



## SpudHarris

Whats the difference between the top two here? Which should I order?


----------



## leeperry

you want to pay 15 bucks a pop, when you could get them for free?

 anyway, my soundcard HP amp has 3 gain settings(0/+12/+18dB), and the 4562/49720 sounded saturated on the highest one(even though the RMAA measurements were slighty better)....but apparently the 2111 sounds better on the top one, the soundstage is much clearer..it was slightly muffled w/ the middle setting.


----------



## Cynips

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_how do they ship btw? Fedex, USPS?_

 

Actually, this time it was a more reasonable plain envelope by ordinary mail


----------



## leeperry

ah, I prefer that actually...always a pain to meet up w/ the UPS/Fedex trucks.

 BTW I've just ordered some LT1028ACN8/LT1364CN8(on top of the LT1229CN8/LT1358IN8 bound to show up)....but apparently you can't beat the 2111 bass anyway


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_you want to pay 15 bucks a pop, when you could get them for free?_

 

Sorry the reason I was asking was because there was an error page everytime I went to the samples page. Anyhoooo I sorted it and have a sample winging it's way to me to test. 

 Thanks for the heads up Leeperry


----------



## leeperry

np 
	

	
	
		
		

		
		
	


	




 and anyway, my problem w/ the mids not being loud enough on the 2111 is gone now that I've set my soundcard gain to the highest(+18 dB)....now I need to set the master volume at the same position as I used to w/ the mid setting on the 4562/49720.

 apparently the 2111 needs high gain, FooTemps also said that he needed to beef up the gain on his amp : http://www.head-fi.org/forums/f5/lit...olling-304261/
  Quote:


 It has come to my attention that the opa2111 has a little bit of artifacting somewhere in the midrange. I'm pretty sure it's because the gain on the mk1 only goes to 8, the thing probably needs more juice. 
 

it does need more juice, and it will keep all your bassheads happy


----------



## leeperry

there's a pic of the internal wafer of a OPA2111 in its PDF : 





 102 transistors, and a pretty crazy pipeline....I guess the latest one(like the THS4032 and others) must have 100 times more transistors?! anyway, they all look identical from the outside, but that's about it.


----------



## majkel

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Ah..not tried the OPA111 or OPA2111 yet. Thanks.

 Wow they're quite expensive, especially the ''KP''. How much do you want for it?_

 

It looks like I paid much more than what Mouser wants for this part. Selling this below $20 shipped stops making sense to me now.


----------



## majkel

Add 22% VAT and duty, or see the Farnell price x1.22 again. Guys from US can have it for cheaper.


----------



## Cynips

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_You will probably get them here. Audioupgardes distribute the Cimarron Stuff so buying direct could possibly be cheaper._

 

Yeah, that seems quite a bit cheaper, even when you consider shipping. Thanks for the info!


----------



## majkel

All I realized in the meanwhile is the lower the number, the less natural the sound LT1364, then LT1361, then LT1358. I'll save myself for wasting money again. The LT1028ACN8 pair is suberb but this op-amp is not fully compensated for G=1 so that's why. 
	

	
	
		
		

		
		
	


	




 I like it the most in my DAC after some auditions of the Gamut CD-3 and realizing what is to obtain using the GS1000's. I should fly with them on my head. The LT1028ACN8 make it happen, the AD797BRZ and the LME49860 do it in a lesser degree. Others don't do it at all. OPA228P will be for sale probably.


----------



## Cynips

Quote:


  Originally Posted by *caesare* /img/forum/go_quote.gif 
_It has all - tonal naturalness (less of the blueness), body, great bass dynamics, smoothness of treble._

 

Exactly how I perceive it, but since I haven't tried out that many other opamps yet, I'll do some more research. Besides, it's fun trying out new samples


----------



## SpudHarris

Well I will order an LT1355 this afternoon. 

 You mentioned the LME49710, I dropped 2 into my L/R of my P3+ last night (on class A adapter sockets) and have to say my memory of them was not what I thought. They sound absolutely brilliant, I've kept them in so I can get used to the difference and to see if they become fatiguing at all over long sessions. Any views on these?


----------



## SpudHarris

Thanks Caesare.

 I've ordered the 1355 and it should be here tomorrow. I'll post my impressions once I've had a chance to listen.


----------



## Bonthouse

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well I will order an LT1355 this afternoon. 

 You mentioned the LME49710, I dropped 2 into my L/R of my P3+ last night (on class A adapter sockets) and have to say my memory of them was not what I thought. They sound absolutely brilliant, I've kept them in so I can get used to the difference and to see if they become fatiguing at all over long sessions. Any views on these?_

 

I have them in my Move right now and listening to em as we speak.
 They are brilliant, oh so clear sounding, that good seperation, great detail, ultra fast and all that. But the bass is a bit lacking, and that's just the part of the music that makes it lively to me. It's a bit analytical.

 Anyway, I've got some AD744's and some AD797's coming to me and I'll check them all out


----------



## SpudHarris

That's what a lot of people say about them. They sound really good in the P3+ but take a little getting used to as they seem to hilite certain dynamics in a different way to most other chips. I couldn't honestly call them natural, not to my ear at least but they are fine. I think you will really like the AD797's, to me they are one of the *finest* OpAmps around. Now where did I put that flame proof jacket??


----------



## Bonthouse

Oh no they certainly aren't neutral. They are kinda euphoric on the upper mids to high freqs but leave the low freqs completely out of the picture.
 They do sound orgasmic with the D2000.. just Wow. The D2000's big bass completely nullifies the shy bass of the LME49710 resulting in a very extending, powerful bass
	

	
	
		
		

		
		
	


	



 Too bad I mostly use the Move with the SE530s


----------



## leeperry

the bass is hollow as hell on these national chips(tame on the NA, loud on the HA..but still hollow)...anyway, there's no perfect chip I'm afraid.

 I want the OPA2111 bass/trebles and the LM4562NA mids/soundstage 
	

	
	
		
		

		
		
	


	




 ok I've also ordered LT1355 samples, these 5 different LT refs should keep me busy for a little while 
	

	
	
		
		

		
		
	


	




 apparently AD won't give samples away, anyone knows what other TI parts I could ask for?


----------



## 12Bass

I suggest trying the OPA2211AIDDA with an adapter.


----------



## leeperry

alright, I might just check this one out after all 
	

	
	
		
		

		
		
	


	




 I already have these OPA211ID you advised me...it's the single version of the 2211A apparently.

 is there any easy way to stick them on adapters? I got a very thin soldering iron and good eyes...I just lack the technique, but I've seen some very inventive ways to "adapt" them 
	

	
	
		
		

		
		
	


	




 but you didn't try the 2111, maybe they're not that different? I've got several discs from Dead Can Dance(Aion/Serpent's Egg) that always souded lousy on the 4562/49720 and they sound really great on the 2111 
	

	
	
		
		

		
		
	


	




 do you guys agree that these National chips increase the mids as hell? it's very obvious on "walk on the wild side", the right guitar in the intro sounds phasey as hell!


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well I will order an LT1355 this afternoon. 

 You mentioned the LME49710, I dropped 2 into my L/R of my P3+ last night (on class A adapter sockets) and have to say my memory of them was not what I thought. They sound absolutely brilliant, I've kept them in so I can get used to the difference and to see if they become fatiguing at all over long sessions. Any views on these?_

 

I started testing these out awhile back and I really like this model.


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_alright, I might just check this one out after all 
	

	
	
		
		

		
		
	


	




 I already have these OPA211ID you advised me...it's the single version of the 2211A apparently.

 is there any easy way to stick them on adapters? I got a very thin soldering iron and good eyes...I just lack the technique, but I've seen some very inventive ways to "adapt" them 
	

	
	
		
		

		
		
	


	




 but you didn't try the 2111, maybe they're not that different? I've got several discs from Dead Can Dance(Aion/Serpent's Egg) that always souded lousy on the 4562/49720 and they sound really great on the 2111 
	

	
	
		
		

		
		
	


	




 do you guys agree that these National chips increase the mids as hell? it's very obvious on "walk on the wild side", the right guitar in the intro sounds phasey as hell!_

 

The 211's are a brand new design and the 2111's are quite dated.
 That is not to say they are bad because of age, just these chips are very different. Compare the specs sheets. 

 To use the 211's your going to need an adapter board and a good knowledge of soldering.


----------



## SpudHarris

I have the OPA211's already mounted ready to test, do they require high gain to be stable? I only ask because my P3+ won't work properly with OPA637's because of the gain requirement. Anyhow I will drop them in for a listen this evening.


----------



## 12Bass

This adapter allows two SOIC singles in one DIP socket:

Single-to-dual Op-Amp Adapter (p/n 020302)

 AFAIK, the OPA211/2211A are unity gain stable.


----------



## 12Bass

Anyone noticed much (any?) difference between LME49710 (single) and LME49720 (dual)?


----------



## leeperry

ok cool! well I've seen some ppl being more inventive than using these...and that'd have been far easier to solder.

 anyway, I've been using the 2111 for +1 day, the bass is simply fantastic....but the mids lack something, I don't really know what it is...they're not "astonishing" as they are on the 4562/49720 
	

	
	
		
		

		
			





 I'm hoping the 1358/1364/1028ACN8 that I should get anytime soon will be a nice in-between the 4562 mids and the 2111 killer bass


----------



## SpudHarris

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Anyone noticed much (any?) difference between LME49710 (single) and LME49720 (dual)?_

 

I don't have the dual version to compare but in theory there shouldn't be a noticable difference unless you run the singles in Class A which I find makes a difference in a good way to all singles I've tried.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Anyone noticed much (any?) difference between LME49710 (single) and LME49720 (dual)?_

 

I have both and I prefer the 710's.


----------



## Bonthouse

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I have both and I prefer the 710's.
	

	
	
		
		

		
		
	


	


_

 

Okay, I'll bite. Why?


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I don't have the dual version to compare but in theory there shouldn't be a noticable difference unless you run the singles in Class A which I find makes a difference in a good way to all singles I've tried._

 

Your using a adapter, with some resistors to bias the opamps into Class A operation?


----------



## SpudHarris

Yes but you can do a neater more permanent job with the smd resistors but as they are about as big as a grain of sand I prefer these.

 I thought I had some pics but don't. If anyone wants to see them Ill take some and post them up.


----------



## diditmyself

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I don't have the dual version to compare but in theory there shouldn't be a noticable difference unless you run the singles in Class A which I find makes a difference in a good way to all singles I've tried._

 

Is there a reason to believe in a difference between a single or a dual opamp in this respect or any respect at all? Is there a reason to believe "class A" biasing of opamps will improve the sound? If a typical buffer is used, with an input impedance of at least 10 MOhm, wouldn't the opamp already be operating in class A?


----------



## bidoux

Since here is an Op-amp thread, I won't be off-topic. I'm looking for the cheapest op-amp to use in the Dynalo power supply. What kind of characteristics should I be looking at ? (slew rate, output current...)


----------



## SpudHarris

If you say so diditmyself


----------



## diditmyself

Quote:


  Originally Posted by *bidoux* /img/forum/go_quote.gif 
_Since here is an Op-amp thread, I won't be off-topic. I'm looking for the cheapest op-amp to use in the Dynalo power supply. What kind of characteristics should I be looking at ? (slew rate, output current...)_

 

A good deal of output current. The alternative is to use any opamp and buffer it. Since the opamps are sinking and sourcing the return currents I guess it should sound good as well.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Yes but you can do a neater more permanent job with the smd resistors but as they are about as big as a grain of sand I prefer these.

 I thought I had some pics but don't. If anyone wants to see them Ill take some and post them up._

 

Sure I would be interested in seeing those Mods...


----------



## SpudHarris

Ok, now where did I put that flame proof jacket?

 Let me start by saying I am not a technical bod but I do have a gift (or a curse), which is a critical ear. I don't know if it is a thing learned over time or just the fact that I have a highly perseptive sense. Either way it's there.

 I was once told that if it sounds good to you then it's good. Even if on paper (spec sheets) it shouldn't. Now with that covered and all you test geeks at the ready with your Multi Meters & Flame Throwers 
	

	
	
		
		

		
		
	


	




 here are some pics of some Class A and some OBCA (Output Bypassed + Class A) AD744's.

 Obviously there are neater ways of doing this especially if you are using SOIC on Brown Dogs. HiFlight (Ron Kerlin) makes and sells the nice neat modules and is far more qualified to comment on the pros and cons of using them.

 Just for reference I have only ever used these in my P3 and P3+ so can't tell you how they fair in different circuits or amps.

 Class A Adapters (AD8610's)





 OBCA AD744's





 Favourites


----------



## diditmyself

I also think I have a critical ear, like most of us do, and I used to believe my amps sounded a lot better when I class A biased the opamps. Then I realised that it's very easy to do this trick live, going back and forth between "class A" and "AB". So I did and now I'm a nonbeliever. There was absolutely no difference at all. I've tried it with both a simple resistor and with active current sources - no difference. Belief is a mighty power. One more thing, just because a trick is audible doesn't mean it's for the better.


----------



## SpudHarris

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_So I did and now I'm a nonbeliever. There was absolutely no difference at all._

 

To your ears.


----------



## diditmyself

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_To your ears._

 

Yes, and if someone could prove the virtues of it in a controlled blinded radomized test I would be a believer again.

 If applying class A to an opamp, go for CCS. The load of a resistor might just increase the distortion. What resistor value are you using?


----------



## SpudHarris

2.2k


----------



## leeperry

oh come on! LT1357 now ?! <clicky, clicky> ok it's the single version of the 1358 
	

	
	
		
		

		
			





 I'm awaiting :
 LT1355CN8 
 LT1028ACN8 
 LT1364CN8 
 LT1229CN8 
 LT1358IN8

 I'm still dubious that the 49720NA can be beaten tbh, it just sounds too damn good!


----------



## leeperry

there's a vague explanation of what the slew rate is here : What do you think about LT1357/1358 opamps?

 I'd still like to try the LT1469 and LT1469-2, but I'm really doubtful that my soundcard has gain of 2 : "_The LT1469-2 is a faster version of the LT1469 but has a minimum gain requirement of 2 for stability._"


----------



## SpudHarris

Is there a single version of OPA2111?


----------



## ROBSCIX

Yes, should be the OPA111
 If I am thiking of the right chips.


----------



## ROBSCIX

I have 3 OPA211 modules I sodlered up the other night. They are great opamps.


----------



## Cynips

Edit: NVM

 On a side note: I got my TI samples today (would've been yesterday if I had been at home for the FedEx delivery. Waiting to test the THS4032CD and OPA2111KP whenever I can get enough quiet time.


----------



## LingLing1337

Quote:


  Originally Posted by ******cap* /img/forum/go_quote.gif 
_I feel that Jim Williams was right in deeming the OPA211 and LT1357 the best audio opamps. And the LM/LME as a honorable 2nd choice.


 BTW among the LME I like the LME49722 best -- coherent and smooth, and not too cold.


 Oh and the OPA211 also makes a very good CMOY opamp... if it supports it (low Ib bipolar), it may give new life to your overlooked CMOY. 
	

	
	
		
		

		
		
	


	


_

 

I'm feeling opampitis comin' on.

  Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_Edit: NVM

 On a side note: I got my TI samples today (would've been yesterday if I had been at home for the FedEx delivery. Waiting to test the THS4032CD and OPA2111KP whenever I can get enough quiet time._

 

Looking forward to both impressions. I find my THS4032CD to be quite bright and much too overbearing for my Grados. I think the DT150 is fairly high ohms though, so I think the THS4032CD should be a good match. They will be installed in your Asus unit?


----------



## SpudHarris

Quote:


  Originally Posted by ******cap* /img/forum/go_quote.gif 
_The OPA211 is incredible. Try and you won't go back. 
	

	
	
		
		

		
		
	


	


_

 

I've got th 211 and I'm not blown away by any stretch of the imagination. I much prefer the 2111.


----------



## leeperry

so Andreas is not god's word after all 
	

	
	
		
		

		
		
	


	




 after listening to the 49720NA very carefully, I don't really see what the fuss is all about.

 if you can justify the US $75 a pop to go burson, they simply seem to be a no-brainer...otherwise for a couple of bucks the 49720NA will hit the spot. I read on a french forum that if the 5532 is 0%, then the 4562 is 70% and the burson 100%.

 like these ppl having zillion pairs of headphones, why not just a very good one instead? like a HD800 or a R10? why collecting/paying for zillion op-amps when you can get a bunch of burson, and simply move on..

 I'm highly doubtful that the LT1358/LT1364/LT1028ACN8 will make me forget about that magical sound the LME49720NA manages to output...but never say never I guess


----------



## 12Bass

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I've got th 211 and I'm not blown away by any stretch of the imagination. I much prefer the 2111._

 

If you haven't already, would you mind to explain what it is that you prefer about the OPA2111 over the OPA211? 

 No personal experience with the OPA2111, though I have the OPA827, OPA2107, LME49720, LM4562, LM6172, LT1358, LT1057, AD823, AD8599, TLE2072, in addition to the OPA2211A and OPA211, as well as a few others which I cannot recall at the moment.


----------



## 12Bass

Haven't made a direct comparison between AD8599 and OPA2211A. Suppose I could have a listen. My earlier thoughts were that the AD8599 was pleasant sounding, with a nice roundness in the lows and a smooth midrange, though somewhat rolled off in the highs, and also very quiet from a noise perspective.


----------



## Cynips

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_They will be installed in your Asus unit?_

 

Yes, which actually begs the question whether I should post my impressions in the STX tweaking thread, this thread or maybe better in the STX tweaking thread and also a link to that post from here. Anyway, it will take a while since I'll be ordering adapters for my 49720HA's so I can switch back and forth more easily.


----------



## SpudHarris

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_If you haven't already, would you mind to explain what it is that you prefer about the OPA2111 over the OPA211?_

 

Am I missing something? What's this Gods Word thing about?

 Anyhow, I don't dislike the 211. It's just that the 2111 seems perfectly balanced with my portable set up and whilst not a natural sounding chip it colours the main genre I listen to beautifully (Trance/Downtempo/Psy-dub/IDM etc....).


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_the 2111 seems perfectly balanced with my portable set up and whilst not a natural sounding chip it colours the main genre I listen to beautifully (Trance/Downtempo/Psy-dub/IDM etc....)._

 

yes, definitely not all-arounders! and on many songs they sound thin and dull compared to the 49720NA IMHO...they're not hi-fi on steroid, they don't impress me.
  Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_What's this Gods Word thing about?_

 

just me playing around 
	

	
	
		
		

		
			





 Andreas has created at least 200 accounts here on head-fi, so when 200 -not so- different ppl keep saying the exact same rehashed thing...it gives more weight to his word, seen from the outside at least 
	

	
	
		
		

		
		
	


	




 apparently the witch hunting is nothing new : http://www.head-fi.org/forums/4353557-post3652.html

 it's still my opinion that it'd be far more efficient to buy a bunch of burson than doing an endless comparison of imperfect tiny $5 chips...they just seem to get EVERYTHING right 
	

	
	
		
		

		
		
	


	




 pricey? yes....but how pricey is US $150 for two dual if they're really perfect


----------



## 12Bass

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Anyhow, I don't dislike the 211. It's just that the 2111 seems perfectly balanced with my portable set up and whilst not a natural sounding chip it colours the main genre I listen to beautifully (Trance/Downtempo/Psy-dub/IDM etc....)._

 

Interesting... what sort of coloration are we talking about? More bass? More detail?

 My own preferences tend toward detail, resolution, and neutrality, and less coloration.... though some coloration can be pleasing. After making some comparisons, I found that the LM/LME parts seemed a bit less "alive" and natural sounding when compared with the OPA211/2211A. IMO, parts like the TL072 have sort of a warm, fuzzy sound which some might like, while I find them veiled in the highs and low in resolution - even the OPA2134/OPA2604 seem to fit into that category, if considerably more resolving than the former.


----------



## SpudHarris

Man two post before I got my reply in to Leeperry!


 Ah, understood but I can assure you I'm not Andreas 
	

	
	
		
		

		
		
	


	




 I still prefer the 2111 though


----------



## Pluto2

Burson opamp?
 You may want to refer to the Audio-Gd opamp thread.....I think they are the OEM.....


----------



## SpudHarris

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Interesting... what sort of coloration are we talking about? More bass? More detail?_

 

Some OpAmps add colour but emphasize certain tones or dynamics that make music you listen to and know well sound too different or even odd in extreme cases. The 2111 is one of the few OpAmps I have tried that colours enough to make this music sound 'Pleasantly' different. If resolution is your bag I think you would like this OpAmp as this is something important with the type of music I listen to. It is detailed and dynamic almost perfect in the right set up 'for me' anyhow. I would consisder this OpAmp a gem at more than twice the price.


----------



## bidoux

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_A good deal of output current. The alternative is to use any opamp and buffer it. Since the opamps are sinking and sourcing the return currents I guess it should sound good as well._

 

Sound doesn't matter, the op-amps used in the power supply are not critical said KG, I'm just lloking for something that won't burn (24V at the input, ±24V).


----------



## leeperry

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Burson opamp?
 You may want to refer to the Audio-Gd opamp thread.....I think they are the OEM....._

 

that's an urban legend I'm afraid...it doesn't seem to hold true for the new burson anyway.

 but they make crazy mark-ups, you're paying for R&D basically....the parts would be $25 or so 
	

	
	
		
		

		
		
	


	




 the OPA2111KP has some major lack in the mids on my system, like a lack of resolution?! sound is thin here...but the bass is out of this world


----------



## 12Bass

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Some OpAmps add colour but emphasize certain tones or dynamics that make music you listen to and know well sound too different or even odd in extreme cases. The 2111 is one of the few OpAmps I have tried that colours enough to make this music sound 'Pleasantly' different. If resolution is your bag I think you would like this OpAmp as this is something important with the type of music I listen to. It is detailed and dynamic almost perfect in the right set up 'for me' anyhow. I would consisder this OpAmp a gem at more than twice the price._

 

Thanks!

 Have you tried OPA827 or OPA2107 (the latter appears somewhat related to the OPA2111 as it is also a Difet)? In general, I've found FET-input devices somewhat less resolving than BJT, which tend to be clearer.... although the OPA827 sounds pretty open and natural, IMO. Actually, I didn't like it that much at first because it sounded kind of "plain", but after more listening, I heard what I take to be a rather uncolored sound.


----------



## SpudHarris

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Thanks!

 Have you tried OPA827 or OPA2107_

 

I have the OPA2107 and really like it a lot. The OPA827's were ordered at the same time as my 2111 from TI.com (thanks Leeperry) but are on backorder so I will get to try them soon.

 I'm compiling a list of other must haves to try.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I'm compiling a list of other must haves to try._

 

I'm awaiting : 
 LT1355CN8 
 LT1028ACN8 
 LT1364CN8 
 LT1229CN8 
 LT1358IN8
 LT1361CN8
 LT1469IN8 
 LT1469IN8 (1469-2)

 but I'll prolly end up ordering Earth Audio-GD or burson's anyway


----------



## leeperry

.


----------



## LingLing1337

I've looked around a bit at the Burson site... so how would one go about installing these?? Would they go into an DIP8 socket or what?


----------



## ROBSCIX

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_I've looked around a bit at the Burson site... so how would one go about installing these?? Would they go into an DIP8 socket or what?_

 

Depending on what your connecting them to they may just pop right in as they are in Dip8 format. 
 For many applications though you require extension wires which they should also sell. They allow you to move the unit around.


----------



## LingLing1337

Move which unit- the opamp unit or the actual device that the opamp is in?\

 By the way, looking at pictures here they hardly look like they are DIP8. So you're saying they would fit into this sort of DIP8 socket?


----------



## leeperry

hummm, there's a guy on this link who says that he prefered his metal 4562 over the OPA Earth : www.review33.com:å½±éŸ³å¤©åœ°

  Quote:


 this is the orignal metal can LM4562 that the audio-gd opamp replaced. They are very good already. At this stage i can't say 100% sure that the discrete sounds a alot better than the LM4562 but there is a difference which i am not able to put in words at this stage. The LM4562 has a very "hifi" type of sound and you thought you are listening to sacd of the same recording. The discrete opamp however has a more analogue sound and may give you an illusion that they are less detailed than LM4562 but in fact all the details are there. 
 

and I've read the same story on a french forum....the guy seemed to prefer the LT1028(better soundstage, better bass) over the Earth and the 4562(bloated bass he said, which is true) in his Rotel CD Player....humm, I can't wait for my LT1028ACN8 samples at this point 
	

	
	
		
		

		
		
	


	




 it would also appear that Sun is better choice than Earth because it works in Class A..

*PS:* another one:

http://209.85.229.132/search?q=cache...&hl=en&ct=clnk

  Quote:


 I found out I prefer Zhaolu D2.5A over Zhaolu D3, and how LM4562 has more "space" and "speed" over OPA-Earth, despite the fact that both were supposed to be more expensive upgrades. 
 

http://wwenze.blogspot.com/search/la...max-results=20
  Quote:


 I remember what happened when I replaced my LM4562 with the OPA-Earth: sound is brought more forward, soundstage is flatter, not good in terms of space. And I'm not the only person with this observation.


----------



## ROBSCIX

Have you checked the spec sheet of the LT1028?

 They are a single channel opamp, IIRC. They will need an adapter.


----------



## leeperry

ahhhhh, I checked so many LT datasheets that I mixed them up 
	

	
	
		
		

		
			





 I guess I'd need 2 adapters like this : Single-to-dual Op-AMP Adapter - DIP version (p/n 021001)

 but I'm not sure they'd both fit in the I/V...plus I'd need 2 more LT1028 samples.


----------



## leeperry

this guy asks US $29 shipped for 4xLT1028CSW on DIP8 adapters : 2x Mono to Dual OPAMP 2x LT1028 -> dual-opamp OPA627 - eBay (item 270425754451 end time Aug-12-09 01:46:17 PDT)

 rather tempting


----------



## Pluto2

LT1028 is not unity gain stable, right? So not fit as a buffer I suppose. And the unity gain stable LT1027 doesn't sound as good? Please correct me if wrong : ) 

 And need to clarify this...... about the metal can LM4562 vs EARTH story..that opa-earth was mine, and we tested both in a T-AMP setting. But the Earth had only a few hours of burn in, and so it was not a fair trial. Incidentally , I think Maijkel might also have not given earth the sufficient burn in time for his testing too......
 Anyway, to make the long story short, a gentleman in this forum recommended 
 the LME49710 to me and said it's very close to earth's sounding , and I bought a pair for this friend to try out in his new DAC, which he liked so much and said if he were listening to analog from his CDs which sounded like his 300B amps....with smooth highs and great resolution. 
 The DAC had a built in NE5532, and later on he switched to a AD845sq but he didn't like it though. His understanding is that his already high resolution system is slightly light in bass, and so that NE5534 complemented it but not the nice AD... So it's all system dependent : )
 And, Initially I wanted to replace all my 12 opamps with discretes in my system, but learning from Majkel's findings, I didn't bother.... : )


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_ahhhhh, I checked so many LT datasheets that I mixed them up 
	

	
	
		
		

		
		
	


	




 I guess I'd need 2 adapters like this : Single-to-dual Op-AMP Adapter - DIP version (p/n 021001)

 but I'm not sure they'd both fit in the I/V...plus I'd need 2 more LT1028 samples._

 

Good thing you got it figured out. May have possibly ruined the circuit if you had of installed them.


----------



## Pluto2

Typo sorry, ad843SQ rather....
 BTW, those Audio-GD discretes all run in class A, and they all draw over 25mA each(single amp).....


----------



## ROBSCIX

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_LT1028 is not unity gain stable, right? So not fit as a buffer I suppose. And the unity gain stable LT1027 doesn't sound as good? Please correct me if wrong : ) 

 And need to clarify this...... about the metal can LM4562 vs EARTH story..that opa-earth was mine, and we tested both in a T-AMP setting. But the Earth had only a few hours of burn in, and so it was not a fair trial. Incidentally , I think Maijkel might also have not given earth the sufficient burn in time for his testing too......
 Anyway, to make the long story short, a gentleman in this forum recommended 
 the LME49710 to me and said it's very close to earth's sounding , and I bought a pair for this friend to try out in his new DAC, which he liked so much and said if he were listening to analog from his CDs which sounded like his 300B amps....with smooth highs and great resolution. 
 The DAC had a built in NE5532, and later on he switched to a AD845sq but he didn't like it though. His understanding is that his already high resolution system is slightly light in bass, and so that NE5534 complemented it but not the nice AD... So it's all system dependent : )
 And, Initially I wanted to replace all my 12 opamps with discretes in my system, but learning from Majkel's findings, I didn't bother.... : )_

 

I have a few dual LME49710HA modules I built up the other night and they are great sounding opamp. I have never compared the two, the Earth and LME but both units are great for audio work.


----------



## Pluto2

Oh, that LM4562 metal can does go a few notches up compared to its plastic counterpart but so is its price tag : )


----------



## leeperry

hummm, the 497222 has a 0.00002 % THD.....the 49720 was 0.00003 % 
	

	
	
		
		

		
		
	


	




 anyway, I still think that the 49720 soundstage is not natural at all! so I don't expect a Earth OPA to "top" it....apparently it'd give a more analog-like audio, which is not what I'm looking for -I think-. I want that digital HUGE magical sound the 49720 gives.

 and some ppl say that the bass is not bloated on the 49720, it's just that it's very tight....and apparently it's very dependent on its surrounding circuit.

 I still think that the bass is far more natural on the 2111, that's for sure! but I'm not sure whether another op-amp could give the same surreal sound as the 49720, w/ better bass response?

 I tried the 49720HA, the bass was overblown and the trebles were not as clear as the NA.

 maybe that guy selling the LT1028 on ebay would be my golden ticket! I see he also does it for the OPA627...and running two singles gives better ground shielding, hence better SQ

 I keep reading that the SS is more 3Dish and that the bass response is much better on the 1028 than on the 4562...oh my


----------



## leeperry

but then the guy says that the mids and details are far better on the 4562 than on the 1028...ideally he'd like the soundstage and the bass response of the 1028 w/ the mids and details of the 4562. no free lunch here 
	

	
	
		
		

		
		
	


	




 I still think that the 4562 cannot be topped w/o drawbacks...bass response seems to have a very high price in the op-amp world.

 and tbh the 49720NA sounds mind blowing on my setup...except that the bass is flabby, but maybe that's how it was on the record to begin w/! it's easy to distort it and make it louder on purpose...I might just use OzoneMP to do that 
	

	
	
		
		

		
		
	


	




 I read some ppl on diyaudio.com saying that they had built 2 DAC's, one w/ the 4562 in I/V and the other one w/o any op-amp....and they said that the 4562 was giving the same exact sound as the other 
	

	
	
		
		

		
		
	


	




 I think I'll wait for my LT1355/LT1364/LT1358/LT1361/LT1469 samples, and see if any of them makes me forget about the 4562 mids/soundstage....otherwise I'll put it back on, and call it day


----------



## leeperry

well, getting crazy compressed bass on the 49720NA is not as hard as it looks 
	

	
	
		
		

		
		
	


	








 I've bypassed every filter but the bass compression, best of both worlds! analog compressed bass and very clear trebles/soundstage


----------



## Pluto2

The belt now goes to OPA2727, and not on LT1355 any more ? So yesterday's hopeless got beaten up by today's desparecidos, haha : )
 Would you say OPA2727 is a more all rounder than opa2211?


----------



## Pluto2

so for +- 15v, what would be your possible top 3 list?


----------



## leeperry

Quote:


  Originally Posted by *desaparecido* /img/forum/go_quote.gif 
_The OPA2727 just lets you forget about opamps_

 

it didn't work for you, now did it ? 
	

	
	
		
		

		
		
	


	




 and are you Mule? Search of All Forums

 many ppl call the LM4562 cold and sterile, I call it uncolored...hum, that 49722 looks very sexy...even lower THD ahmagad 
	

	
	
		
		

		
		
	


	




 PS: I'm gonna ask a friend to put the soic8 LT1028/OPA211/LME49722 and LME49720HA on DIP8 adapters...that should give!


----------



## leeperry

well, the improved specs of the 49722 over the 49720 don't seem to come for free: diyAudio Forums - National opamp inflation - Page 1

 I've got no idea of how my souncard would react


----------



## LingLing1337

OK so #1- will a discrete opamp work well in the integrated HP amp in a DAC?
 #2-I'm guessing that OPA-Earth is the way to go for a discrete with warm, natural, analog-like sound?


----------



## leeperry

Quote:


  Originally Posted by *desaparecido* /img/forum/go_quote.gif 
_No problem at all._

 

I've read on a french forum a guy comparing the 49722 and the 4562 on a CD player, he said the 49722 seemed more detailed and more neutral(no screaming mids).

 ok, I want two of these on DIP8 now


----------



## ROBSCIX

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_OK so #1- will a discrete opamp work well in the integrated HP amp in a DAC?
 #2-I'm guessing that OPA-Earth is the way to go for a discrete with warm, natural, analog-like sound?_

 

1. You would have to check the circuit to verify compatibility.
 2. The Earth is very neutral, but tube like. Atleast in my experience.


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I've read on a french forum a guy comparing the 49722 and the 4562 on a CD player, he said the 49722 seemed more detailed and more neutral(no screaming mids).

 ok, I want two of these on DIP8 now 
	

	
	
		
		

		
		
	


	


_

 

Different circuits. You can't guess how it will sound in your application without trying it for yourself.


----------



## leeperry

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Different circuits. You can't guess how it will sound in your application without trying it for yourself._

 

good point! but most everyone will agree that the bass is flabby on the 4562...and that's how it is for me too.

 maybe that's how it is on the recordings, though 
	

	
	
		
		

		
		
	


	




 anyway, the 49722 is clearly an improved 49720....and I just love the 49720 sound, so it's only logical that I try this part 
	

	
	
		
		

		
		
	


	




 Dusty Springfield sounds so damn good on the 49720NA


----------



## LingLing1337

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_1. You would have to check the circuit to verify compatibility.
 2. The Earth is very neutral, but tube like. Atleast in my experience._

 

Pardon my ignorance, how can I know whether it is compatible? I know I could swap it in for sure, but is there a way to tell if it would perform to its potential in my DAC?
 2. Thanks for the suggestion


----------



## ROBSCIX

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_Pardon my ignorance, how can I know whether it is compatible? I know I could swap it in for sure, but is there a way to tell if it would perform to its potential in my DAC?
 2. Thanks for the suggestion 
	

	
	
		
		

		
		
	


	


_

 

I just mean generally. First off, check and see what is used in there stock. 
 If we know what the designer used stock we can give you sugegsitons that would be a upgrade oer the stock units.


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_good point! but most everyone will agree that the bass is flabby on the 4562...and that's how it is for me too.

 maybe that's how it is on the recordings, though 
	

	
	
		
		

		
		
	


	




 anyway, the 49722 is clearly an improved 49720....and I just love the 49720 sound, so it's only logical that I try this part 
	

	
	
		
		

		
		
	


	




 Dusty Springfield sounds so damn good on the 49720NA 
	

	
	
		
		

		
		
	


	


_

 

Many will also say opamps sound different at various voltage levels also. The circuit plays a major part in overall sound quality. 
 You can use other impressions only to a certain extent. You will only know for sure once you test it and see if it works good for your application. 
 I think this is a reason many of us have such large collection. A personal tells us about one more opamps that sounds great and "wow, you have to try this!"
 Searching out new opamps and testing gets to be a bit of a addiction for some.


----------



## leeperry

yeah, I can see how some ppl would develop some serious OCD about op-amps 
	

	
	
		
		

		
		
	


	




 I really don't wanna go this route, I'll try the LT samples...then the OP211/LM49722, and if I still prefer the 49720NA I'll still be very happy w/ the SQ!


----------



## ROBSCIX

Quote:


  Originally Posted by *desaparecido* /img/forum/go_quote.gif 
_That's true, but only to a certain extent. At any rate, the LME49722 sounds like the french guy described it (compared to an LME49720HA regarding the upper mids, and to the LM4562NA regarding detail). 
	

	
	
		
		

		
		
	


	





 My problem with these LME's is that they're all not-quite-natural tonally._

 

Well I guess eveybody has their opinions, that is why this thread is a good idea.
 So we can compare notes on the various opamps.
  Quote:


  Originally Posted by *desaparecido* /img/forum/go_quote.gif 
_Ah and the opa-Earth is not tube-like warm for sure. To hear what warmth is try the LT1358. 
	

	
	
		
		

		
		
	


	


_

 

 I guess that also depends on your gear and ears.
 I think warm is not really a good description of them. They are very Valve like with some warmth but they are fairly neutral IMO...
 That being said, I would say they are warmer then many chip opamps I have heard.
 I have the LT1358's and from what I can remember they aren't a very warm opamp. 
 This is what I mean though, what your using them in and what your using them for can influence the sound quite a bit. You speakers/cans are also a factor.
 Peoples opinion on the various opamps can vary quite a bit I think. 

  Quote:


  Originally Posted by *desaparecido* /img/forum/go_quote.gif 
_For me: either I stay with the near-perfect OPA2727 or I return to the two OPA211 or I test the LT1632. Or maybe I try the LME49722 again just to make sure that the OPA2727 is better, like I thought last time. 
	

	
	
		
		

		
		
	


	


_

 

I have not tested the OP2727 yet, does it have the "Burr-brown" sound that many like? Will have to try it out.
 I have a few modules of the OPA211 tried them quickly but will have to try them for a extended period to see what they have to offer.
 Thx for the suggestions.


----------



## LingLing1337

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I just mean generally. First off, check and see what is used in there stock. 
 If we know what the designer used stock we can give you sugegsitons that would be a upgrade oer the stock units._

 

Stock I have an NE5532. Which I like for how natural it is, but I'm looking for an upgrade. So I'm thinking of going with a dual OPA-Earth or OPA-Moon.


----------



## ROBSCIX

Quote:


  Originally Posted by *desaparecido* /img/forum/go_quote.gif 
_Heh as usual in forum talk there are different ways to conceive the same terms... So I call warm what is colored of red or another "warm" color, and cold what is colored of blue or another "cold" color. So the LT1358 for me is really warm, just like, say, the LME49860 is cold._

 

Yes, I think it is just diffent descriptions from different people using different gear!
  Quote:


  Originally Posted by *desaparecido* /img/forum/go_quote.gif 
_The Earth was not much colorful (neither warm nor cold) so... I don't really seem to remember tubes sounding that way, anyway...I guess it's impossible for opamps to exactly sound like tubes._

 

 I find the Earth very neutral, not overly Valve like. Certain charachteristic remind me of tubes. Again, just a quick impression.
 I like them for I/V because thy don't overly color the soudn compared to many other units I have tested.


  Quote:


  Originally Posted by *desaparecido* /img/forum/go_quote.gif 
_Definitely it does, and in its best shape. Just don't go above +12V or +/-6V_

 

I figured it would, BB opamps sem to have a very charachteristic sound that they all share. Come have variations in response but I find the all have the same "color"
 Yes, I was looking over the spec sheet awhile ago and noticed the CMOS construction and low voltages.


----------



## ROBSCIX

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_Stock I have an NE5532. Which I like for how natural it is, but I'm looking for an upgrade. So I'm thinking of going with a dual OPA-Earth or OPA-Moon._

 

The generic 5532 is in a socket? Do you have any opamps on hand to test out?


----------



## LingLing1337

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_The generic 5532 is in a socket? Do you have any opamps on hand to test out?_

 

I only have the THS4032. By the way, I would definitely like something colder than the 5532. But warmth is a quality that I like.

 EDIT: To the poster who said that the HDAMs might not be suitable for a 12v application, the Audio-GD web site lists ±9 TO ±25V as the proper range for everything but the Sun V2, which I'm not so interested in.


----------



## ROBSCIX

Yes, but check the voltages in your units. You say 12 volts...
 does that mean +/- 12 volts? 12 volts total -so +/-6 volts?

 You will need to verify this voltage an what it actually means.


----------



## Pluto2

sorry guys, earlier when I said about the recommendation on LM49710 from a gentleman in the forum, which should be sounding close to an 'opa-moon', but not earth ....as I recall, we compared the metal can LM4562 along with earth and moon......


----------



## LingLing1337

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Yes, but check the voltages in your units. You say 12 volts...
 does that mean +/- 12 volts? 12 volts total -so +/-6 volts?

 You will need to verify this voltage an what it actually means._

 

My wallwart is rated at 12v.


----------



## Filburt

.


----------



## leeperry

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_My wallwart is rated at 12v._

 

measure it, it's prolly outputtting 15V or so.

 and ideally measure it on the PCB under load while the DAC is running

 my previous soundcard had a 9V rated adapter, that was actually outputting 13V idle and 11V under load.

  Quote:


 National would like to thank you very much for your sample order for the LME49722MA.


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_



_

 

Oh dear, if only they knew hehe


----------



## leeperry

I'm having wet dreams about an improved 49720NA w/ even lower THD at this point 
	

	
	
		
		

		
		
	


	




 I demand a LME49724 w/ 0.00001% THD 
	

	
	
		
		

		
		
	


	




 and the more it goes, the more I think that the 49720NA shows you the bass as it is on the record....some amps will compress/increase its response, but it's not necessarily more balanced/accurate to the source material IMHO


----------



## LingLing1337

Quote:


  Originally Posted by *Filburt* /img/forum/go_quote.gif 
_Dovresti trovare un'altra passatempo, Andrea. Non è sano continuare in questo modo _

 

Let me take a stab here-
 You should find another pastime, Andrea. It's not sane to continue in this manner.

 Italian, right?
 Pluto2, right?


----------



## zoiberg

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_I only have the THS4032. By the way, I would definitely like something colder than the 5532. But warmth is a quality that I like.

 EDIT: To the poster who said that the HDAMs might not be suitable for a 12v application, the Audio-GD web site lists ±9 TO ±25V as the proper range for everything but the Sun V2, which I'm not so interested in._

 

±9 is 18v so 12v is not enough


----------



## ROBSCIX

Quote:


  Originally Posted by *zoiberg* /img/forum/go_quote.gif 
_±9 is 18v so 12v is not enough_

 

It is impossible to know exactly how the power is utilized in the circuit from the input voltage. You can have a 12V input and have many different voltage swings for the amplifier section, including +/- 12 V. Which is more then enough power for the discrete opamps. It is hard to know exactly what is being supplied to the opamp without measuring it directly.


 @LingLing1337
 Do you have any type of manual or spec sheet which would outline the voltage swings for this opamp in the circuit?
 Aside from measuring the opamps directly you could contact the company that makes the unit and ask them what the + and - supply voltages are for the 5532 in this design.


----------



## LingLing1337

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_@LingLing1337
 Do you have any type of manual or spec sheet which would outline the voltage swings for this opamp in the circuit?
 Aside from measuring the opamps directly you could contact the company that makes the unit and ask them what the + and - supply voltages are for the 5532 in this design._

 

No, you see, the DAC is a, erm... Beresford. So no spec sheets. I could try contacting Beresford NA and see if they know. I'll let you know if I find out. Jeff from Beresford NA, when I previously asked him about discretes, said that the unit they tried worked very well.


----------



## ROBSCIX

OK, wasn't sure about that. Contact the company and ask them about the supply voltages for the 5532 opamp.


----------



## leeperry

ok, even the pros recommend the 49722 : rme adi-8 qs op-amps [photos] - Gearslutz.com


----------



## Pricklely Peete

Ling if you have a DMM just measure the V across the + pin (8 Vcc) and - pin (4 or gnd) of the opamp while it's up and running. Look at the data sheet to find the correct pins to make sure.... http://www.datasheetcatalog.org/data...ild/NE5532.pdf

 Anyway this will give you a fairly close idea of the + - V running through the stage. I'm assuming you know how to use a digital multi meter so if you have not used one read up on how to use one properly. Plenty of good stuff from google and you tube in this regard.


 Peete.


----------



## LingLing1337

Quote:


  Originally Posted by *Pricklely Peete* /img/forum/go_quote.gif 
_Ling if you have a DMM just measure the V across the + pin (8 Vcc) and - pin (4 or gnd) of the opamp while it's up and running. Look at the data sheet to find the correct pins to make sure.... http://www.datasheetcatalog.org/data...ild/NE5532.pdf

 Anyway this will give you a fairly close idea of the + - V running through the stage. I'm assuming you know how to use a digital multi meter so if you have not used one read up on how to use one properly. Plenty of good stuff from google and you tube in this regard.


 Peete._

 

Thanks, I'll see if I can borrow a DMM from someone.


----------



## leeperry

Quote:


  Originally Posted by *dead can dance* /img/forum/go_quote.gif 
_This morning I received new LME49720NA samples (in a different looking DIP package from that of my old LME49710NA, BTW)_

 

"new"? "different" ? you're looking for the best op-amp and you call the 49720NA "new" 
	

	
	
		
		

		
		
	


	




 this chip kicks butt! 
	

	
	
		
		

		
		
	


	




 are you saying that the 49722MA is not as good as the 49720NA? I still wanna try it anyway 
	

	
	
		
		

		
		
	


	




 some photos of what you call "new package" would be much appreciated 
	

	
	
		
		

		
		
	


	




 so I shouldn't bother w/ LT1358/1355/1364/1469 etc etc??


----------



## finax

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_No, you see, the DAC is a, erm... Beresford. So no spec sheets. I could try contacting Beresford NA and see if they know. I'll let you know if I find out. Jeff from Beresford NA, when I previously asked him about discretes, said that the unit they tried worked very well._

 

The Beresford 7520 have a line voltage of 10V in the opamp area.


----------



## LingLing1337

Quote:


  Originally Posted by *finax* /img/forum/go_quote.gif 
_The Beresford 7520 have a line voltage of 10V in the opamp area._

 

Thanks. Any other valuable information such as this regarding the 7520 you care to share? (By the way, for some reason this post sounds very sarcastic. It is not.)


----------



## SpudHarris

Hey guys check out this e-bay seller.


----------



## LingLing1337

And if 10v isn't enough to plug in an Audio-GD unit, then what is a natural, analog-sounding opamp to cure my digitis?


----------



## zoiberg

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_It is impossible to know exactly how the power is utilized in the circuit from the input voltage. You can have a 12V input and have many different voltage swings for the amplifier section, including +/- 12 V. Which is more then enough power for the discrete opamps. It is hard to know exactly what is being supplied to the opamp without measuring it directly.


 @LingLing1337
 Do you have any type of manual or spec sheet which would outline the voltage swings for this opamp in the circuit?
 Aside from measuring the opamps directly you could contact the company that makes the unit and ask them what the + and - supply voltages are for the 5532 in this design._

 

If he uses the Beresford dac the opamp is supplied from a single regulated +10v, (7810 regulator)
 Negative pin of the op-amp is tied to ground

 The noise of those Audio GD op-amps is not good with low supplies , 10v is NOT suitable


----------



## zoiberg

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_And if 10v isn't enough to plug in an Audio-GD unit, then what is a natural, analog-sounding opamp to cure my digitis?_

 

Have you tried any op-amps with FET input? these can sound a little smoother than bipolar input types


----------



## ROBSCIX

Quote:


  Originally Posted by *zoiberg* /img/forum/go_quote.gif 
_If he uses the Beresford dac the opamp is supplied from a single regulated +10v, (7810 regulator)
 Negative pin of the op-amp is tied to ground

 The noise of those Audio GD op-amps is not good with low supplies , 10v is NOT suitable_

 


 This may be the case, I told him to check it over with the company to verify the voltages. The point being unless you know how the circuit is operating you cannot just guess because of the 12V Wallwart.
 There are many ways to change this input to higher voltages and positive and negative swings.

 If the internal circuitry is running at 10V then the circuit is not suitable for discrete opamps.


----------



## Pricklely Peete

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_"new"? "different" ? you're looking for the best op-amp and you call the 49720NA "new" 
	

	
	
		
		

		
			





 this chip kicks butt! 
	

	
	
		
		

		
		
	


	




 are you saying that the 49722MA is not as good as the 49720NA? I still wanna try it anyway 
	

	
	
		
		

		
		
	


	




 some photos of what you call "new package" would be much appreciated 
	

	
	
		
		

		
		
	


	




 so I shouldn't bother w/ LT1358/1355/1364/1469 etc etc??_

 

You do realize you are trying to reason with Andrea don't you ? At the best of times his logic is hard to follow.....best ignore the troll...his post will soon disappear along with his latest persona.

 Peete.


----------



## leeperry

I'm just amazed that someone SO deeply obsessed w/ op-amps.....didn't bother trying the 49720NA.

 and now all the blabla about the LT chips has become m00t?! even the LT rep I talked to told me "Audio is not an application that we have focused on, but our parts are often selected for high-end systems."

 at least National did this LME serie ONLY for audio circuits...and they had some pretty bad ass audio equipment for QA, from what audioman54 said on diyaudio.com


----------



## Filburt

.


----------



## majkel

When you learn how to use the AD797, especially the BRZ suffix series, other op-amps stop to matter. This is why I stopped discussions about any op-amps. The idea is to properly use pin 8 in order to adjust THD and bandwidth compensation. No dual op-amp provides access to other parts of the op-amp architecture than inputs and outputs. For top notch performance it doesn't suffice. The AD797BRZ looked to me as the best op-amp many times, with proper decompensation it's far better. It outperformed my last favorite OPA228P being decompensated by default. Read the AD797 datasheet carefully and good luck in experiments! Similar functionality for far less money you have with the AD8021 but this one is nasty and doesn't accept supply voltages more than 26.4V total.


----------



## majkel

Quote:


  Originally Posted by *dead can dance* /img/forum/go_quote.gif 
_Jim Williams said..._

 

I don't know who it is, and I don't want to know. It's obvious this guy hasn't tried the BRZ series and/or he didn't manage to have proper bandwidth compensation. The AD797BRZ is like I stated in my review - the OPA627 and the AD797ANZ qualities put in one chip, with no their flaws transfered. This is with pin 8 left alone. When you hit the spot with the capacitance - around 30pF to ground in my circuit, it improves strongly. If you want to stay with Jim's claims, it's your choice and be happy with unsuccessful op-amp rolling during next two years.


----------



## majkel

The LT1028ACN8 (I burnt the CN8 pair the other day, so no comments) is a bit drier and with narrower soundstage than the AD797BRZ, both default and decompensated. The AD797ANZ is drier than both. I can try them decompensated and see what the difference will be against the BRZ series.


----------



## Filburt

.


----------



## leeperry

Quote:


  Originally Posted by *dead can dance* /img/forum/go_quote.gif 
_for my Super Pro the best opamps so far have to be the LME49720 and LT1355_

 

ok cool! well I've ordered some samples and adapters, so I'll be trying the 49722 and LT1028CS8...plus all these LT DIP8 samples, if I ever receive them 
	

	
	
		
		

		
		
	


	




 but, indeed, the 49720NA doesn't make you wanna roll opamps anymore...you get to think "what for?"


----------



## SpudHarris

Most of the above as stated are either personal preference or governed by particular circuits/applications. In my P3+ I have tried a few of the LT OpAmps (recommended to me) and personally can't take to any of them wholly. The 1355 and 1124 are nice but not the last say in this amp circuit IMO. I've also tried 1468's and 1357's.

 I know it's subjective but in the same way Tangent wrote of the OPA637's (love those by the way) is there a leader or must have LT chip? I haven't tried the LT1028's yet. 

 Just for reference my preference with nearly all other OpAmps is Buf 634's (Hi-C) and AD797's in G/V this is almost a default I work with as it suits pretty much everything I try in L/R.

 Cheers in advance.


----------



## ROBSCIX

No one opamp will be perfect fit for anybody. If that was the case this thread wouldn't go very far. I am sure we all have our favorite opamps for various jobs but people have drastically different tastes in music and response.


----------



## majkel

Quote:


  Originally Posted by *ratatouille* /img/forum/go_quote.gif 
_They killed the thread. 
	

	
	
		
		

		
			




Au diable le AD797, the best opamp is the OPA211 (not OPA2211)._

 

Tried to use pin 8 yet? The OPA211 doesn't even reach the transparency level of the OPA228P. I made a completely crazy tweak yesterday but it works for the AD797 great - I put a 56pF capacitor between pin 8 of both op-amps. Marvellous! Better than grounding this pin which makes sound a bit treble oriented. Less capacitance - less efect, greater capacitance - worse than without, most probably due to positive feedback created and oscillations.


----------



## Cynips

Quote:


  Originally Posted by *ratatouille* /img/forum/go_quote.gif 
_the best opamp is the OPA211 (not OPA2211)._

 

Do you say this from experience of both or are you just stating that it is the single version you've heard and love?


----------



## majkel

Quote:


  Originally Posted by *ratatouille* /img/forum/go_quote.gif 
_Err, the OPA228P? Will try it. But the OPA211 has everything, not just transparency but dynamics, body, natural tonality..._

 

I told you, all compensated op-amps sound confined. The OPA211 does as well. The OPA228P makes sounds independent but the source images are still slightly corrupted in their threedimensionality.
  Quote:


 Did you maybe connect pin 8 of both opamps (the left and right channels) through a 56pF cap? 
 

Yes I did. You have to fine tune the capacity for your application. It looks like full decompensation does no harm to mine. 
  Quote:


 Myself, I don't believe in tweaking the chips that way. 
 

It's not tweaking! It's following the datasheet hints! 
	

	
	
		
		

		
		
	


	




 Even grounding pin 8 via capacitors works fine but this way it does even better due to effect of cancelling both internal capacitances via the external capacitor. The datasheet is for any application, also just one channel so then you have no other choice than using the ground. It has its drawbacks especially when the ground isn't completely clean. The trick I described is the smartest way of cancelling the internal compensation capacitance. Whether it works for you - it depends on the circuit.
  Quote:


 I detest any class A biasing or decompensations or such. Perhaps because I mostly judge opamps by tonal quality, then comes transparency and all the rest. I'm not looking for extraordinary soundstage (I don't use headphones) or other funny things. 
	

	
	
		
		

		
		
	


	



 

Most modern op-amps suffer from this trick however people are happy just due to following another stupid suggestion. It worked very well indeed for the ancient OP27GP.


----------



## majkel

Same with the OPA2228 against 2x OPA228. Must be a cross-talk issue. The OPA2111ID against OPA211AID is a slight difference and I think the AID has got a nicer tone while the ID is more neutral. The same thing appeared when I compared the OPA2228P to OPA2228PA - the latter is darker but a bit too colored at the same time.


----------



## majkel

I agree with the dullness but the OPA2227 is much more duller and has got uninvolving timbre. Pretty enough to detest this chip.


----------



## majkel

The LME49722 wans't optimal in my circuit. I still preferred the LME49720. OK, I'll dig through some more datasheets for some useful application hints. 
	

	
	
		
		

		
		
	


	




 For the AD8021 it helped much, for the AD797 it helped quite a bit but on a higher quality level, so the total result is outsanding. Let's see what the competition suggests.


----------



## 12Bass

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_The OPA2111ID against OPA211AID is a slight difference and I think the AID has got a nicer tone while the ID is more neutral._

 

These are not related chips. The dual version of the BJT OPA211 is the OPA2*2*11A. OPA2111 is FET.


----------



## majkel

I meant OPA211AID against OPA211ID. Sorry for the typo. There is nothing like OPA2111AID, they can be KP, AM, BM, SM.


----------



## leeperry

ouh I love the LT1358IN8 so far, very energetic(especially the bass)! the 49720NA sounds flabby and hollow in comparison 
	

	
	
		
		

		
		
	


	




 huge soundstage, and it seems far more stable than the LM/LME on my soundcard! I guess the only way to know what sounds good *TO YOU* on *YOUR* setup is to roll opamps until the end of days 
	

	
	
		
		

		
		
	


	




 and it doesn't have the ugly mids of the 2111 
	

	
	
		
		

		
		
	


	




 I can understand why many DIY'ers always make sure to NEVER use op-amps, they're really evil...and most likely your circuit's weakest link 
	

	
	
		
		

		
		
	


	




*PS:* the LT1358 makes you feel like this basically : http://www.youtube.com/watch?v=Zdz88MBWomo


----------



## leeperry

OPA2727? which sample should I pick? Precision Amplifiers - Low Offset Voltage - OPA2727 - TI.com

 I'll put them on browndog adapters, together w/ the OPA211/LT1028/LME49722 
	

	
	
		
		

		
		
	


	




 PS: indeed, the mids were screaming on the 49720NA compared to the LT1358


----------



## Cynips

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_OPA2727? which sample should I pick? Precision Amplifiers - Low Offset Voltage - OPA2727 - TI.com_

 

ROBSCIX seemed to think the input voltage of the STX/ST was too high for the OPA2727. I'd like to know for sure too.


----------



## leeperry

alright, ordered. thanks!

 any other DIP8 TI chip I could try?

 I wonder if a Moon/Earth or Burson would be even better than this LT1358....probably


----------



## leeperry

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_ROBSCIX seemed to think the input voltage of the STX/ST was too high for the OPA2727. I'd like to know for sure too._

 

ahhhhhhhhh, good thing I didn't press "ORDER" yet 
	

	
	
		
		

		
		
	


	




 one thing I know is that our cards are rather picky w/ opamps....the 49720NA didn't work too well for me, and I love that LT1358 so far 
	

	
	
		
		

		
		
	


	




 it sounds very wide, natural and percussive


----------



## leeperry

but the OPA2727 cannot work on 12V, can it? it's 12V max swing, so that's ±6V 
	

	
	
		
		

		
			





 and can I try the LT1229 on my soundcard? or is it like a VERY bad idea?

 the upper spectrum is rather dark on the 1358, but it doesn't sound like grind paper being applied into your inner ear at least 
	

	
	
		
		

		
		
	


	




 maybe a tad more trebles would be good, I got so many more LT samples pending anyway 
	

	
	
		
		

		
		
	


	




 I will use OPA211 on adapters, is there any point that I try the OPA2211A as well?


----------



## Filburt

12V is the specified max but you may be able to run it higher. I've run the OPA2727 at up to about 14V or so. I'd personally use a THS4032 for I/V on a PCM1792 like the config of the STX. The 2727 would be more appropriate for the reconstruction filter afterwards, although it wouldn't be my first choice.


----------



## 12Bass

Quote:


  Originally Posted by *Filburt* /img/forum/go_quote.gif 
_... I'd personally use a THS4032 for I/V on a PCM1792 like the config of the STX._

 

Just curious... when a chip is used for I/V, how does that change its impact on the sound, say, compared to using it in an output section? Just wondering how the sonic artifacts imparted by a device might differ depending on application? For example, should one expect a relatively neutral chip like the AD797 to sound neutral when used for I/V (assuming, hypothetically, that it had a sufficiently high slew rate)? Or should one expect a different sort of response for devices when use in an I/V application?


----------



## Filburt

.


----------



## 12Bass

Thanks Filburt,

 Perhaps my confusion lies in that I'm unsure about what is going on during I/V conversion and what sort of demands it places on the I/V conversion device (commonly an opamp). Above, it is implied that greater bandwidth is desirable in this application; however, I'm not sure why. It's more of a curiosity anyway, as none of my DACs require I/V... though curiously, I have a Sony ST-S555ES tuner which uses current output (which has been modified to voltage).


----------



## leeperry

ok thanks Andrea for the additional infos, and Filburt for the tip! I will order a bunch of THS4032 samples if they offer good synergy w/ my DAC 
	

	
	
		
		

		
		
	


	




 I think I'll order the 4031 instead, the crosstalk is pretty bad on the 4032....and a very skilled friend of mine will be soldering them on adapters anyway

http://focus.ti.com/docs/prod/folder...t/ths4031.html

 THS4031CD or THS4031ID? the ID is more expensive and has better temp. specs, should I go for this one?


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_ok thanks Andrea for the additional infos, and Filburt for the tip! I will order a bunch of THS4032 samples if they offer good synergy w/ my DAC 
	

	
	
		
		

		
		
	


	




 I think I'll order the 4031 instead, the crosstalk is pretty bad on the 4032....and a very skilled friend of mine will be soldering them on adapters anyway

High Speed Amplifiers (Greater than equal to 50MHz) - Voltage Feedback - THS4031 - TI.com

 THS4031CD or THS4031ID? the ID is more expensive and has better temp. specs, should I go for this one?_

 

THS4031, are single channel soic. You will need adapters and a very steady hand.


----------



## ROBSCIX

Quote:


  Originally Posted by *Filburt* /img/forum/go_quote.gif 
_12V is the specified max but you may be able to run it higher. I've run the OPA2727 at up to about 14V or so. I'd personally use a THS4032 for I/V on a PCM1792 like the config of the STX. The 2727 would be more appropriate for the reconstruction filter afterwards, although it wouldn't be my first choice._

 

Sure, you might get away with runnig it 1 volt over. These guys are talking about running this opamps at over twice it's Max recommended voltage.

 I cannot see that ending very well.


----------



## Pluto2

Excellent finding on ADA4898-1 Kim : )
 Hi Filburt, have you compared this ADA chip with AD797? JW claims its much better than LME49722MA.....


----------



## 12Bass

Got a pair of the ADA4898-1 around here somewhere, along with a pair of the AD797. Just haven't had a chance to audition them yet. Not sure if I have the proper adapter for the SOIC ADA parts, however. I'll be giving the LME49720/LT1358/LM4562/OPA211/OPA2211A a listen soon as well.


----------



## Pluto2

.....and nicer than AD8599, with better stability etc. than AD797 too : )

 12Bass, please do!!!


----------



## Pluto2

And costs only $5 each too! Wondered why there's been so little reviews......I guess it's skepticism, judging from data charts showing it's not an audio chip and is not a good video chip either : )


----------



## ROBSCIX

Will have to try that one. I have many AD units but haven't heard of that model.
 I will need to review the spec sheets.


----------



## Filburt

I don't know why Andrea thinks the ADA4898-1 is more stable than the AD797; it's a 65MHz op-amp with no internal feedback and a single stage high gain VAS. ADI doesn't even specify the audio band performance on it, and it looks like it may just not be as optimized as the 797 for that type of use. It looks more like something you'd maybe use with a high speed ADC than an audio app. The THS4051 is OK. I didn't find it to be superlative.

 leeperry - The crosstalk spec on the THS4032 is at 1MHz. If you look at the graph, it's probably better than -90dB in the audio band. I doubt you'll do better using the browndog single-to-dual adaptor.


----------



## Filburt

Andrea, I'm not sure why either you or Jim (at least, so you say) have trouble with the AD797 (although in Jim's case I'm more inclined to think it's something reasonable). There are many factors which may be responsible with a device such as this. After working with it for a few months, I found it isn't particularly easy to use, relatively speaking. However, the performance has been good for me since I got some sense of what to do with it. Since I don't subscribe to innateness mysticism when it comes to electronic devices, it doesn't strike me as particularly strange that there will be some divergence of experience based on usage alone. There's also the issue, of course, that some devices just don't work well in certain circuits (such as AD797 as in integrator I/V).

 You're free to like whatever you like with these things, but any serious exercise in using high performance chips probably requires a serious exercise in learning appropriate application. That isn't to say to say a particular design doesn't place constraints such that potential performance is bounded, but it does mean that inference and conjecture based on some sort of organic principle about op-amps is a largely frivolous exercise.


----------



## leeperry

Quote:


  Originally Posted by *Filburt* /img/forum/go_quote.gif 
_leeperry - The crosstalk spec on the THS4032 is at 1MHz. If you look at the graph, it's probably better than -90dB in the audio band. I doubt you'll do better using the browndog single-to-dual adaptor._

 

well, I read majkel saying that single op-amps usually yield better results than dual, simply because nothing's shared between the 2 channels?!

 I've ordered a handful of browndogs, and my friend will be soldering :
 -4x OPA211
 -4X LT1028
 -2x LME49722MA

 he's cool w/ soldering, but indeed the adapter PCB will also add noise...so what you gain on one end might actually be lost on the other 
	

	
	
		
		

		
			





 maybe I'll just order some OPA2211 and THS4032 instead 
	

	
	
		
		

		
		
	


	




 should I take the more expensive(better temperature specs) versions of the THS4032? I guess the enclosure/wafer is better quality


----------



## Filburt

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well, I read majkel saying that single op-amps usually yield better results than dual, simply because nothing's shared between the 2 channels?!

 I've ordered a handful of browndogs, and my friend will be soldering :
 -4x OPA211
 -4X LT1028
 -2x LME49722MA

 he's cool w/ soldering, but indeed the adapter PCB will also add noise...so what you gain on one end might actually be lost on the other 
	

	
	
		
		

		
		
	


	




 maybe I'll just order some OPA2211 and THS4032 instead 
	

	
	
		
		

		
		
	


	




 should I take the more expensive(better temperature specs) versions of the THS4032? I guess the enclosure/wafer is better quality 
	

	
	
		
		

		
		
	


	


_

 

You're certainly welcome to try the single to dual route but I don't care for the layout on those adaptors. I'm not sure it would materially improve crosstalk, though. I don't know what majkel means by "nothing's shared"; if you're using a single to dual adaptor, you're still using the same source of power for both and issues such as common mode signals are still present. It also conceivably would make bypass more difficult. Also note, for whatever it's worth, I use the Aries adaptor digikey stocks (part no. A744-ND) instead of browndog. I'm not sure if the better temp spec chip performs better; I guess it depends on what that materially means. If it means it dissipates heat better or that the internal parts are more stable over a longer range of temperatures, it could conceivably mean something to thermal distortion. However, it could mean various other things, too.


----------



## leeperry

ahhhhhhh, so do you think browndog's are still OK? or the Aries are simply much better? coz I already ordered them 
	

	
	
		
		

		
		
	


	




 IIRC majkel said that he had the best results w/ single op-amps, but it's true that many ppl have their own theories on op-amps....strangely enough, magical thinking seems very common in the op-amps world(like Andrea and his op-amp numerology theory 
	

	
	
		
		

		
		
	


	




)

 PS: wow the Aries is $7 a pop, the browndog's are $2.39..


----------



## Filburt

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_ahhhhhhh, so do you think browndog's are still OK? or the Aries are simply much better? coz I already ordered them 
	

	
	
		
		

		
		
	


	




 IIRC majkel said that he had the best results w/ single op-amps, but it's true that many ppl have their own theories on op-amps....strangely enough, magical thinking seems very common in the op-amps world(like Andrea and his op-amp numerology theory 
	

	
	
		
		

		
		
	


	




)

 PS: wow the Aries is $7 a pop, the browndog's are $2.39.._

 

Hmm...well maybe he's right; I don't know. The browndogs will probably work fine for the most part. I've had trouble sometimes with them on high speed circuits. The layout is kind of circuitous and maybe this is the source of the trouble. Note that pins 4/7 on the chips are going to go to the same place on the adaptor (pins 4/8), and that pins 2/3/6 will go the same place as though you were using a dual, so it's not exactly isolated. So, this is going to mostly come down to whether the source of the problem is package design and may be ameliorated by this adaptor. I guess it's conceivable.


----------



## leeperry

hehe ok, well you know I've always been dragged off the THS4032 coz there's always someone saying that it requires a very specific design...

 I don't know the gain of the I/V op-amps on my soundcard, so it's just like the LT1028/1128 differences...or the LT1469/LT1469-2, some of these are not unity gain stable, and some need a gain of 2 or more!

 apparently a high slew rate can also easily oscillate if the circuit gain is not high enough? so playing god w/ switching op-amps on a circuit you know nothing about seems like a terrible hit & miss job 
	

	
	
		
		

		
		
	


	




Mod your Beresford 7520 - Page 47 - The Art of Sound Forum

  Quote:


 "Oscillating op-amps distort the sound badly, and that's what you are enjoying and calling "SOOO OOOOOPEN", distorted sound. Most pre-amp mods are actually based in making some stage oscillate by accident, but don't say it too loud or some people may become upset... (Anyway, the kind of people that does this stuff neither have an oscilloscope to check nor care about stability at all)." 
 

 Quote:


 "You can't use the THS4032 for most audio applications because IT'S NOT UNITY-GAIN STABLE, and most audio circuits require that condition. This op-amp is only stable for gains of 2 or higher, as it's intended for video buffering applications. There is no simple way to make it unity-gain stable.

 Also, you can't use the THS4032 with +/-15V in a PCB designed for conventional op-amps because it requires specific layout considerations in order to handle those 0.45W of idle dissipation. *Furthermore, most PCB layouts designed for conventional audio op-amps just can't handle the 100Mhz bandwidth.*" 
 

for instance, the 49720NA has never been stable for me on whatever the Asus STX or ST...on the STX the sound was badly drifting the first time I put them on, and on the ST they were utterly bass shy and very hollow.

 so this is indeed a hit & miss 
	

	
	
		
		

		
		
	


	




 the LT1358 has a gain bandwidth of 25Mhz, and the LME49720 55Mhz...apparently bigger is not always better


----------



## Filburt

.


----------



## leeperry

ok thanks for clarification!

 indeed, I'm lacking a lot of knowledge here..still the LT1469-2 w/ its 200MHz bandwidth would give poor results on the Asus soundcards I guess?

Linear Technology - LT1469 - Dual 90MHz, 22V/us 16-Bit Accurate Operational Amplifier

Linear Technology - LT1469-2 - Dual 200MHz, 30V/Î¼s 16-Bit Accurate AV â‰¥ 2 Op Amp

 LT told me "The LT1469-2 is a faster version of the LT1469 but has a minimum gain requirement of 2 for stability."

 and fzman also said that sometimes what ppl call open and very detailed.......is actually an op-amp that's badly oscillating, just like this person said too : diyAudio Forums - Behringer SRC2496 A/D D/A with THS4032 - Page 1

 I've seen some ppl in this thread adding resistors on their SOIC8>DIP8 adapters to turn them into Class A(like all the Audio-GD op-amps apparently)...but I guess that's something else than what you are mentionning.

 it takes a rocket scientist diploma to master all that op-amp stuff


----------



## Filburt

Yes, there are probably a lot of DIY mods and projects out there where oscillation is present somewhere. It's not _always_ the case, though. I've fortunately had the benefit of plenty of instrumentation to help me avoid such things, though, and that has also helped me a lot in learning how to use these devices.

 For the most part, this is guesswork when I'm going to suggest something, since I don't have an Asus STX. However, I do know the constituent parts rather well (including the PCM1792), and I have some idea of how to make high speed chips work in rather adverse conditions. Still, keep that in mind; I can't absolutely guarantee success but I can try my best to help you out.

 It looks like the LT1469-2 could be used for I/V as it's -1 stable, but uh...I don't see what's so special about it? It's not very fast, especially on the settling, and the distortion performance isn't superlative. Is this something Andrea recommended?

 I was not referring to biasing the output, no; although you could do that if you want I guess. You'd need to figure out how much you want to bias it and select the appropriate resistor value.


----------



## majkel

I performed a specific test yesterday, comparing several op-amps to voltage DAC output without a buffer. The most similar sound was using the OPA211ID, then the OPA827AID, then the OPA228P, followed by the AD797BRZ and the LT1028ACN8. The OPA211 seems to be just transparent, the OPA827 is just a bit more edgy and colorful. The OPA228P sounded "nicer than the original" but caused slight sound corruption. The AD797BRZ made a bit of soundstage mess, it was enormously wide and the sound was a bit on the bright side. The LT1028ACN8 sound was a bit on the hard side and very slightly limited in the space. Actually I have to repeat the LT1028 against OPA211 comparison as I'm not sure about the Linear. However it is clear I could recommend the OPA827 for I/V stages, and the OPA211 as a next stage of filtering.


----------



## majkel

Andrea, it's a great idea. I built a numerous amount of portable amps using the OPA2613 as the ground channel driver but I never thought about using it as a plain buffer. However you have to cut off the DC chain to the OPA2613 due to its nasty input bias currents that could strain the DAC out. I'm looking forward to reading your impressions as I almost ran out of OPA2613 stock.


----------



## Filburt

Quote:


  Originally Posted by *bullett* /img/forum/go_quote.gif 
_"mysticism" is your word, and it denoted how far your incapacity to understand my reasoning reaches. *There's nothing mystical, it's just natural diversity. Everything is born unique.* Why do you need to revert to mysticism to understand this? It would merely take a bit of analogical thinking. You're sooo narrow minded._

 

 Quote:


  Originally Posted by *bullett* /img/forum/go_quote.gif 
_Now I'm interested in trying the OPA2613 that I just received... maybe the OPA2830 too.


 The OPA2613 has great promise: both from a scientific point of view (datasheet) and from an unscientific one *(my numerical theory says, without possibilities of mistake, that its tonality will match the CS4398 chip quite well)*. Will report back._

 

This is what I mean by mysticism, Andrea. Anyway, it's not important and not worth clogging up a thread over it. I hope your new project goes well.


----------



## leeperry

Quote:


  Originally Posted by *Filburt* /img/forum/go_quote.gif 
_Yes, there are probably a lot of DIY mods and projects out there where oscillation is present somewhere. It's not always the case, though. I've fortunately had the benefit of plenty of instrumentation to help me avoid such things

 It looks like the LT1469-2 could be used for I/V as it's -1 stable, [..] Is this something Andrea recommended?_

 

well, I asked LT about a good op-amp for I/V audio application, that's their answer :
  Quote:


 Audio is not an application that we have focused on, but our parts are often selected for high-end systems. Some good parts to consider include:

 LT1468 (low distortion, low current noise, low voltage noise)
 LT1678
 LT1364
 LT6231 (for lower supply voltage apps)

 The LT1469 is not restricted to 16-bit DAC applications. In fact, if you look at the LM4562 part you list below, THD+N is somewhere around 70dB. This is nowhere close to even 16-bit performance. The LT1469-2 is a faster version of the LT1469 but has a minimum gain requirement of 2 for stability.

 Of the parts listed below, the 1364 is available in DIP-8 so maybe that's your best choice. One of our guys who plays with this part in the lab reported that he saw distortion performance that was even better than is suggested by the graphs in the data sheet. He said it was low to the point that he had trouble measuring it. 
 

I'm not sure how he came up w/ the LM4562 having 70dB of THD(or did he mean SNR?)..

 also, I've seen an oscilloscope sold for rather cheap, but could I just plug it on the Essence output? I guess not...


----------



## 12Bass

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I performed a specific test yesterday, comparing several op-amps to voltage DAC output without a buffer. The most similar sound was using the OPA211ID, then the OPA827AID, then the OPA228P, followed by the AD797BRZ and the LT1028ACN8. The OPA211 seems to be just transparent, the OPA827 is just a bit more edgy and colorful. ..._

 

Interesting... although it has been some time since I compared OPA211 to OPA827, I seem to recall thinking that the OPA211 had perhaps just a little more clarity and detail, while the OPA827 sounded more flat, with slightly less sparkle, without adding much color of its own. Initially, I thought the OPA827 was a bit "boring", until I listened a bit more and heard its subtle, but seemingly natural sound. Definitely like the midrange reproduction out of both these chips.

 P.S. TI/BB should make an OPA14. I'm sure that one would sell like hotcakes.


----------



## Cynips

Tried the LT1358IN8 on my ASUS Xonar Essence STX and posted my impressions in another thread. I then switched in the LT1057ACN8 and you can read about those findings later in that thread.


----------



## Cynips

Quote:


  Originally Posted by *sickntired* /img/forum/go_quote.gif 
_I'm so happy with the LME49720HA that I might also solder it on the socket 
	

	
	
		
		

		
		
	


	





 But I guess I won't. It's so nice to change flavor according to the season. The LME49720HA is my ideal summertime opamp. 
	

	
	
		
		

		
		
	


	


_

 

What's the setup you're listening to the 49720HA's in?


----------



## Cynips

Quote:


  Originally Posted by *sickntired* /img/forum/go_quote.gif 
_I saw on ebay the LT1057 being sold in the metal can version too. Might be a great idea..._

 

Oh, that sounds tempting. How much for? I would seriously be interested in that considering how dramatically better the 49720HA sounded to the NA in my setup. Though, of course, this is a different manufacturer so it might be a completely different thing altogether.

 Edit: I see that the H signifies the metal can version, which is no longer manufactured. However, $27-28 seems a bit pricey unless you can't find them anywhere else. You have any idea what the other letters mean? AH and MH were those I saw there on eBay.


----------



## SpudHarris

I have absolutely NO metal can OpAmps in my collection, can someone tell me why or if they are better? I notice that they are more expensive than normal/standard OpAmps so that kind of implies that they are better, are they??


----------



## Cynips

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I have absolutely NO metal can OpAmps in my collection, can someone tell me why or if they are better? I notice that they are more expensive than normal/standard OpAmps so that kind of implies that they are better, are they??_

 

I think they've been described as "military grade". I only have experience with the LME49720NA and LME49720HA but the difference between these two is huge. The HA is very neutral, warm and controlled, while the NA sounded hollow, fluffy and unbalanced.


----------



## ROBSCIX

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_I think they've been described as "military grade". I only have experience with the LME49720NA and LME49720HA but the difference between these two is huge. The HA is very neutral, warm and controlled, while the NA sounded hollow, fluffy and unbalanced._

 

The HA's are less suceptible to noise or other intereference. Most that have tested both NA and HA version will say the HA sound better.


----------



## leeperry

Quote:


  Originally Posted by *sickntired* /img/forum/go_quote.gif 
_Now I need the adapters from Browndog to make things look more professional 
	

	
	
		
		

		
			



_


----------



## leeperry

yeah, I'm not sure wth these Chinese guys are doing : LT1057MH - Google Images

 they bent the TO99 parts into DIP8 sockets, that they insert into DIP8 sockets again 
	

	
	
		
		

		
		
	


	




 but apparently the Audio-GD parts are also like this, whatever w/ or w/o extensions you end up w/ a DIP8 socket....that you can either solder on your PCB or insert into another DIP8 socket 
	

	
	
		
		

		
		
	


	




 I don't really see how soldering a TO99 package could make any difference over bending.....especially w/ fzman(who's quite a handy craftsman and confirmed me that these TO99 49720HA are the _hoochie mama_) who told me that bending is more optimal because it will bypass any distortion added by the adapters.

 the browndog's do seem to increase latency and lower the contact "quality"...look at their other adapters : Single-to-dual Op-Amp Adapter (p/n 020302)

  Quote:


 Low *loss* traces: 12 mil minimum trace width, 25 mil wide power and output traces


----------



## Cynips

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_the browndog's do seem to increase latency and lower the contact "quality"...look at their other adapters : Single-to-dual Op-Amp Adapter (p/n 020302)_

 

I'm sorry, but I don't see why that would add any latency? Contact quality I'm pretty sure would depend mostly on the soldering stage.

 But getting my hands on a pair of metal can LT1057's, that would be extremely interesting, just not for $28 a piece+shipping... especially when there's no guarantee whatsoever that they will sound any better.


----------



## leeperry

I believe Filburt had problems w/ the browndog and high slew rate op-amps...besides you're still dependent on the quality of the interconnections within the adapter...hence they talk about "low loss" on the browndog website. and fzman told me that the less adapters the better, the electronics shop I've been in contact told me the exact same thing : any adapter will weaken the signal quality.

 and to get back on the why a single SOIC8>dual DIP8 would be better than a dual SOIC8>dual DIP : Single-to-dual Op-Amp Adapter (p/n 020302)

  Quote:


 Superior electrical and thermal isolation between channels vs. integrated dual op-amp


----------



## ROBSCIX

Quote:


  Originally Posted by *sickntired* /img/forum/go_quote.gif 
_Well this is too good. This evening it seems even better - isn't it maybe opamp burn in? 
	

	
	
		
		

		
		
	


	





 I'm so glad I got 5 samples of the LME49720HA. They won't be wasted. 
	

	
	
		
		

		
		
	


	






 Now I need the adapters from Browndog to make things look more professional 
	

	
	
		
		

		
		
	


	


_

 

Yes, get the adapter.


----------



## Filburt

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I believe Filburt had problems w/ the browndog and high slew rate op-amps...besides you're still dependent on the quality of the interconnections within the adapter...hence they talk about "low loss" on the browndog website. and fzman told me that the less adapters the better, the electronics shop I've been in contact told me the exact same thing : any adapter will weaken the signal quality.

 and to get back on the why a single SOIC8>dual DIP8 would be better than a dual SOIC8>dual DIP : Single-to-dual Op-Amp Adapter (p/n 020302)_

 

Yeah, I see they claim that. I just wonder about what sort of greater isolation it's going to give electrically. I can see the thermal isolation, but on the other hand it does make the issue of doing bypass trickier.

 Maybe what I'll try to do in the next couple months is pick up a couple of these and try to quantify the overall performance again with some ideas I have for getting the HS chips not to act up so much. It's really circuit dependent, too; probably in certain applications it wouldn't be a problem at all.


----------



## Cynips

Quote:


  Originally Posted by *sickntired* /img/forum/go_quote.gif 
_Looks like I'm going to try the LT1057ACH, rather than the TO99 OPA2134... 
	

	
	
		
		

		
		
	


	


_

 

Did you find a cheaper place to get them from than eBay?


----------



## ROBSCIX

TO-99 LT1057's those might be interesting to try out.


----------



## majkel

Hahaha! Changing your mind each day. Since yesteday, I've been back with my beloved OPA2228P. 
	

	
	
		
		

		
		
	


	




 They are compatible with Grado GS1000, and show best results with the PS1000 and the HD800. Let's just agree that between several types of op-amps you get top notch performance but... there is something about those decompensated op-amps...


----------



## 12Bass

From my experience, OPA827 has a relaxed, unaffected sort of sound, one that might be criticized by some as lacking excitement. After listening to a lot of opamps, I don't have much use for the OPA2134... lots of them sitting around that I don't know what to do with. To my ears, it's veiled and "phasey" sounding.


----------



## ROBSCIX

Quote:


  Originally Posted by *cippo lippo* /img/forum/go_quote.gif 
_





 This is an endless useless whirl. 
	

	
	
		
		

		
		
	


	





 The numbers tell the truth. You only have to trust. 
	

	
	
		
		

		
		
	


	






 The LM4562 is the most natural sounding opamp for my DAC. Exactly what numbers predicted. But I wouldn't listen. 
	

	
	
		
		

		
		
	


	





 The OPA2211 and the OPA827 are quite nice, but none of them reaches the simple naturalness of the LM4562... Coincidence? Nah! 
	

	
	
		
		

		
		
	


	


_

 

Sorry, no you have to trust your ears. The numbers really tell you very little about the end sound quality. The LM4562 are great opamps but they are not right for everybody. If you like the LM4562 great, but don't assume everybody else will also.


----------



## majkel

Quote:


  Originally Posted by *cippo lippo* /img/forum/go_quote.gif 
_BTW, maybe I'll keep swapping once in a while LM4562 - OPA827 - OPA211 'till the end of time, just because it is nice to just change sometimes. 
	

	
	
		
		

		
			



_

 

Good point! This is exactly what it's all about. Just look at users of tube equipment. Are they happy with their setups? In most cases no, they just keep rollin'.


----------



## n_maher

Just an FYI for everyone not named Andrea reading this thread. Andrea registers several user names a day (a clear TOS violation), often carries on conversations with himself between accounts (just weird, I mean how lonely are you?), and posts the same thing over and over again (boring, old, tired, we get it). He's been permanently banned from this site and regardless of how many times he tries we're going to keep doing the same thing. As such, you'll probably see posts disappear from this thread from time to time which are, on the surface nothing "delete" worthy. But that's what is going to continue to happen. Every account will be banned, every post removed, no exceptions. If it upsets you how it makes the thread disjointed you can blame Andrea. We tried letting him back in and told him to behave himself, he didn't last.


----------



## ROBSCIX

Do whatever you ned to do to keep the membership composed of high quality, positive contributors.


----------



## diditmyself

Numbers and colors. Maybe not only synesthesia. Is there a touch of schizotypal personality trait?


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Good point! This is exactly what it's all about. Just look at users of tube equipment. Are they happy with their setups? In most cases no, they just keep rollin'. 
	

	
	
		
		

		
		
	


	


_

 

Many of the opamps sound very good, just different.


----------



## Gbjerke

How would this affect signature

 OPA2111PK. in L/R
 Transistor Buffers
 2 Single AD 797s in G/V?

 On a P3+. Am i right when saying i will get extended treble and stronger bass?


----------



## leeperry

OPA2111PK had dead mids for me...nice bass, though.


----------



## 12Bass

OPA827 has a sweet midrange, IMO.


----------



## ROBSCIX

I like the OPA827's also. The AD797's are also great sounding opamps.


----------



## SpudHarris

Quote:


  Originally Posted by *Gbjerke* /img/forum/go_quote.gif 
_How would this affect signature

 OPA2111PK. in L/R
 Transistor Buffers
 2 Single AD 797s in G/V?

 On a P3+. Am i right when saying i will get extended treble and stronger bass?_

 

That set up on a P3+ is sweeeeet. I had that set up for ages.


----------



## majkel

Quote:


  Originally Posted by *noisy* /img/forum/go_quote.gif 
_I believe that it's utopian to expect to reach a state of perfect transparency just playing with chips and caps. 
	

	
	
		
		

		
		
	


	


_

 

It depends on the criteria you set, especially when you find such an aspect that is fulfilled by only one device. I feel the OPA228P opens the door no other op-amps have opened so far, so this made me staying calm since foreyesterday. However, keeping other op-amps in the chain problably keeps this corridor closed anyway. Try a headphone amp with no op-amps to be sure you left the clear path to be able to hear what is there to be heard from the DAC. 
 There is also a possibility that you don't want this because it could cut off the most part of the fun which is rolling. The HD800 told me the OPA228P is the right one, the PS1000 said the same, the GS1000 where more hesititating but cooperate very well with the OPA228P in the DAC so I remain satisfied with these assumptions.


----------



## leeperry

hah, you guys change your minds every week(day?)....ok I'll order some OPA228P free samples <clicky, clicky> 
	

	
	
		
		

		
		
	


	




 LT says my samples are "shipped", but 3 weeks later still nothing on my end 
	

	
	
		
		

		
		
	


	




 the bass is flabby on the 4562NA, this I won't change my mind!

 my friend has given me my 49720HA back, so whenever I'll get my soundcard back from RMA....I'll try them again! I loved them on the STX


----------



## majkel

I haven't changed my mind in terms of getting rid of internal compensation. I liked the AD797 decompensated for a while but after another test it turned out unoptimal. So I went back to the OPA228P. I cannot use the AD8021 in my curcuit due to high supply voltage.


----------



## leeperry

ah well, I can only use dual DIP8 or single SOIC8(on adapters).....and the only SOIC8 they give as sample is the lowest grade(OPA228UA against OPA228U)


----------



## majkel

You can try the UA, there is just a bit more of "musical" coloration and a tad darker sound. The decompensation gain should be audible to you believing your head amp is "clean".


----------



## leeperry

ah well, I'm not really looking after a dark sound....and that'll be a waste of browndog adapters, considering I'll always think that there's a higher grade 
	

	
	
		
		

		
			





 anyway, so far I loved the LT1358IN8....maybe the LT1057ACN8/LT1355CN8 will change my mind, but I think it fulfilled all my needs


----------



## leeperry

Jim Williams also praised the LME49722 here : rme adi-8 qs op-amps [photos] - Gearslutz.com

 I wonder what parts Rupert Neve would like


----------



## ROBSCIX

The 2132 and 2134 are common generic audio opamps that have been used for a long time.


----------



## SpudHarris

Yeah, they sound like it too 
	

	
	
		
		

		
		
	


	




 so anyhoooo, based upon the earlier post I decided to try them both as I have loads lay around from when I used to sell cmoys. Now I know why they are lay around and not in my heavy rotation box, man they are pants.......


----------



## majkel

Quote:


  Originally Posted by *SuperbOld* /img/forum/go_quote.gif 
_And with good reason... if there's an LME I'd use it's that. But it's not for all seasons.


 It certainly doesn't have the very emotional sense of body of the OPA2132P. I wanna hear the OPA132UA... as it was said (on Audio Asylum, sure not here) to be an improved revision of the original OPA2132._

 

UA series is the SOIC equivalent of the PA series, applies to the U and P series respectively.


----------



## fzman

wow -- i didn;t even know that about myself-- having never been called a 'handy craftsman' before. not sure i ever referred to opamps as 'hoochie mamas' either -- but as an inveterate punster I am sure it has something to do with the leg-bending. what next, I'll start using emoticons!


  Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_.....especially w/ fzman(who's quite a handy craftsman and confirmed me that these TO99 49720HA are the hoochie mama) who told me that bending is more optimal because it will bypass any distortion added by the adapters._


----------



## fzman

on a more serious note, i think power supply considerations, beyond operating voltage and adequate current have a lot to do with the results people are getting/will get from various opamps. the has in my stx very much benefit from the outboard choke-filter linear psu i built. i just got a riser board, so i can use a pci card in a pci-e slot,-- which comes with a 4-pin molex to supply power -- i'm gonna use it for my re-capped prodigy hd2 which has been thru several opamps, and is sounding very good through my diy headphone amp and denon 7000s.


----------



## Pluto2

I would really like to try out the ADA4898-1, though no dual version is available yet....

 According to JW, ADA4898-1 is much better than LME49722MA - it has better low end depth and extension, much better top end details. He also finds AD8599 to sound soft with transients, less bass and top end extension than the ADA4898-1.


----------



## Pluto2

So, according to a product manager at Analog, the ADA4898-2 is still in development stage (need some design changes), so it is hard to finalize the release schedule. The earliest possible release date will be in 1Q2010......fyi


----------



## majkel

So why would the UA improve over the PA? Did guys from Audio Asylum sleep well last year? 
	

	
	
		
		

		
		
	


	




 The ADA4898-1 seems to be the direct competitor to the OPA211. And now I know for sure - the OPA228P is what I like and the OPA211 is what is true but some recordings suffer from the OPA228P coloration and sound corruption. I prefer to stay calm because of hearing what I should hear, so let's get used to the OPA211... again, after a long break.


----------



## majkel

Ok, now it's clear to me. I can say for sure that the OPA2132PA was a little bit better than the OPA2134PA but the OPA2132P is a resonable step forward. However I still preferred the OPA2228P to them.


----------



## majkel

OK, so you have numbers 1 and 2. In the OPA211 the 2 is preceding the two 1's. In the LT1122 two 1's precede the pair of 2's. Which number configuration is more optimal?

 I owned the AD8599 and "soft transient" is the last thing I would say about this chip. I compared them to the AD797 one day and the AD797 sounded more analog, darker and smoother, with better soundstage extension. So I stopped to buy this fragile chips - they like to blow when plugged to a supplied socket.


----------



## tacitapproval

Computer = 666. The numbers tell all!


----------



## ROBSCIX

Quote:


  Originally Posted by *SuperbOld* /img/forum/go_quote.gif 
_If it makes you feel good...


 But I don't see anything "generic" in what is one of the most sophisticated midranges of the opamp world, chip or not. That of the OPA2132P.


 No I wouldn't associate OPA2132P to OPA2134PA... Look at the price.





 I'm not denying that the OPA2211 will sound better overall, even without some of the sophisticated midrange character of the OPA2132P. I'm also not denying that 2x OPA827 have about the same sophisticated midrange of the OPA2132P, but a perceivably higher level of resolution.

 But for a dual DIP opamp... the OPA2132P is my current favorite with the LT1358. 
	

	
	
		
		

		
		
	


	


_

 


 If it makes me feel good? 

 Suggesting these opamps are generic is not putting down their quality by any means. The suggestion to me means they are used in a great deal of audio equipment because they are decent enough units.
 Also, don't use price as any indicator of quality...


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_OK, so you have numbers 1 and 2. In the OPA211 the 2 is preceding the two 1's. In the LT1122 two 1's precede the pair of 2's. Which number configuration is more optimal?

 I owned the AD8599 and "soft transient" is the last thing I would say about this chip. I compared them to the AD797 one day and the AD797 sounded more analog, darker and smoother, with better soundstage extension. So I stopped to buy this fragile chips - they like to blow when plugged to a supplied socket._

 

I have both the AD8599 -just built that one haven't had much time to test. I also have a AD797.

 The 8599 seem to be recommended a great deal when speaking about AD opamps.
 I guess by your posting that you prefer the AD797 to the 8599?
 Do you have any opinions on AD8620 or 8610?


----------



## leeperry

BTW, Gearslutz.com - View Single Post - ART MPA Gold Mods

  Quote:


 Any opamp change must be viewed on a scope to determine if it's operating in a linear region.[..] Audio band parts like OPA2134, AD 8599 are usually safe, the LM4562/LME49720 is a 55 mhz bandwidth part, watch out. The LM6172 is a 100 mhz part.
*This is not like swapping the tubes on your old color TV, one can quickly make things worse without knowing it. * 
 

Home Recording - View Single Post - LME49720NA for ART Digital MPA?
  Quote:


 The motorboating is oscilations, if you socket chips you really need to use machined sockets the flat pin ones are bad for oscilations and moaterboating and usually need decoupling caps across power an ground 
 

the stock 2114D on my soundcard have a 15Mhz slew rate, I think 50Mhz and above is over the top as it's too far from the original design...plus the damn thing has very crappy sockets 
	

	
	
		
		

		
			





 the first time I put 49720NA in there, they gave a wooshy sound...constantly oscillating.

 so the lower the gain bandwidth, the better I'll be doing I think...the LT1358 has a 25Mhz gbw, and it sounded FAR more stable than any LM/LME part I tried..

*PS:* damn, some of my LT samples were "shipped" 3 weeks ago.....they use pigeons to ship them?


----------



## leeperry

humm, I can get a pretty huge oscilloscope for 90 EUR at a pawnshop...its last calibration has expired a few months ago.

 I still dunno how to measure if an opamp would be oscillating


----------



## Pars

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_humm, I can get a pretty huge oscilloscope for 90 EUR at a pawnshop...its last calibration has expired a few months ago.

 I still dunno how to measure if an opamp would be oscillating 
	

	
	
		
		

		
		
	


	


_

 

Look at the output and recall what the definition of oscillating is... you may see a waveform of some sort at up to several MHz (or possibly more). Any sort of ringing on the output would indicate a problem (no signal on the input).


----------



## leeperry

alright, but I can't just plug it on the audio output? I have to measure two pins of the opamp I guess?


----------



## ROBSCIX

Do you have any experience with a O-scope?


----------



## leeperry

yep, from school like 20 years ago


----------



## Cynips

Just wrote about my impressions of the OPA2111KP as well as a comparison of the LT1358CN8#PBF with the LT1358IN8 I reviewed before.


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_yep, from school like 20 years ago 
	

	
	
		
		

		
		
	


	


_

 

Looks like time to start re-learning it all over again. Surely there must be a helpful "howto" somewhere on the intaweb, or a techie friend?

 You can just check the output of the amp, OR you can check the pins on the op-amp. Your results will probably differ. What I did to check the amp output was to build a test plug - 1/4 inch TRS plug with 2 load resistors (similar value to your 'phones - I used 33 ohm 5 watt) and that gives you a convenient place to hook the probe onto.

 Oscillation - the most severe sort will just look like a broad blur and you will probably have to switch up to a very fast timebase to see the individual cycles of the signal. With nothing playing you should get a clean straight line - not blips or spikes or blurry fuzzy crap. try switching through all timebase ranges - some artifacts only show well at certain scan speeds. A sine wave test tone should look like a clean drawn curvey line, but if the scan is too slow a large number of cycles will get blurred together, too fast and you will only see a small portion (nearly horizontal) of one cycle. You will need to translate time to frequency and vice-versa (use the 1/n button on your calculator).

 Also, you are getting very hung up on the op-amps themselves, but if you do get a scope, then I suggest you take a good look at the power rails. You must always consider the power pins as a signal input also.


----------



## leeperry

oh ok! well I've seen some USB oscilloscopes on ebay for pretty cheap..

 anyway, anyone knows the difference between CN8/ACN8/IN8 on LT chips? it's not documented anywhere


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_oh ok! well I've seen some USB oscilloscopes on ebay for pretty cheap..

 anyway, anyone knows the difference between CN8/ACN8/IN8 on LT chips? it's not documented anywhere 
	

	
	
		
		

		
		
	


	


_

 

Read the supplier's datasheets. It's all in there. e.g. N8 is packaging, A/C/I are spec levels.


----------



## leeperry

ahhh, good point thanks! so I is the extreme temp version?

 but Cynips said he prefered the 1358C over 1358I....so a higher grade IC doesn't necessarily mean "better" SQ? 
	

	
	
		
		

		
		
	


	




 I've also ordered extreme temp version samples of TI chips(THS4032 and so)


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_ahhh, good point thanks! so I is the extreme temp version?

 but Cynips said he prefered the 1358C over 1358I....so a higher grade IC doesn't necessarily mean "better" SQ? 
	

	
	
		
		

		
		
	


	



_

 

Chances are that given the same assortment of chips you will follow a different journey and come to a different conclusion. Every case is unique, and the number of variables are numerous. Comparing opamps tells just as much about the accompanying circuit as the chip itself. Don't just limit yourself to comparing op amps, you will also have to try (e.g.) all possible combinations of power supply bypass capacitors.


----------



## leeperry

well Cynips has pretty much the same soundcard as mine, and so far the LT1358 is one of my fav 
	

	
	
		
		

		
		
	


	




 I'll check the 1355/1364/1469 and especially 1057 before making up my mind, but I only ordered the more expensive extreme temp versions 
	

	
	
		
		

		
		
	


	




 but anyway, it's appear that between two batches of the same exact opamp you could also have slight SQ differences...and the I/C versions seem to be identical, it's just that the I are speced as extreme temp...where the C could work, but are not guaranteed to do so


----------



## Bonthouse

Quick question guys, has anyone noticed a difference between the AD797ARZ and the AD797BRZ?

 I requested BRZ's, but got ARZ's..


----------



## majkel

Should be. At least there is a difference between BRZ and ANZ, the latter beign spec-wise the same as ARZ.


----------



## Bonthouse

Hmm, ah well, I soldered the AD797ARZ's in my Corda Meier Move just now and they make the Grado SR80 sound amazing!


----------



## leeperry

where did you get them? what price?


----------



## Bonthouse

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_where did you get them? what price?_

 

I contacted Analog in The Netherlands and requested some sample opamps.
 They sent me two (I asked for six total) and I didn't have to pay a thing
	

	
	
		
		

		
			





 Try to contact AD in your country for some samples that aren't available at the site.


----------



## fzman

Google Translatefound these in my web travels, and think they would be interesting for finicky opamps. this is the english translation, if i got it right. any thoughts, help from anyone in sweden re: pricing and availability? reputation of this company??


----------



## leeperry

*@Bonthouse*: ok cool, I'll do that! by email?

 BTW, what's the diff between U and UA on TI op-amps? Precision Amplifiers - Low Offset Voltage - OPA228 - TI.com

 they don't say anything in the PDF, and they only offer the cheaper UA as free sample.

 and AD doesn't say anything in the PDF about the different grades of the 797 : AD797 | Ultralow Distortion, Ultralow Noise Op Amp | Military/Aerospace | Other | Analog Devices

 more expensive = better, but why?

 I've also called LT to know why it was taking a month to get samples, and they told me that they receive them from Singapore...and then they have to package them and ship them from your local country, so it takes forever...plus they don't bother putting the DIP8 parts in plastic holders, so they're completely mashed up and require pliers to unfold them 
	

	
	
		
		

		
		
	


	




 and when you read stuff like this, you realize that rolling op-amps on a board you know nothing about...and without an oscilloscope, is a terrible hit & miss :


----------



## Bonthouse

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_*@Bonthouse*: ok cool, I'll do that! by email?_

 

I went at them like crazy! Email, phone and even snailmail!


----------



## majkel

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_and AD doesn't say anything in the PDF about the different grades of the 797 : AD797 | Ultralow Distortion, Ultralow Noise Op Amp | Military/Aerospace | Other | Analog Devices_

 

It does. Look at the charts.
  Quote:


 more expensive = better, but why? 
 

Spec-wise, sound-wise.


----------



## leeperry

ah right! there's the AD797A and the AD797B...and the B seems to drift less, hence it's higher grade 
	

	
	
		
		

		
		
	


	




 but 797B has a min gain of 2, where 797A is 1...isn't that better 
	

	
	
		
		

		
		
	


	




 still TI is not clear on the diff between U and UA ?! Precision Amplifiers - Low Offset Voltage - OPA228 - TI.com


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_*@Bonthouse*: 
 AD doesn't say anything in the PDF about the different grades of the 797 : AD797 | Ultralow Distortion, Ultralow Noise Op Amp | Military/Aerospace | Other | Analog Devices_

 

What datasheet do you have? I have rev. E and it shows specs for the 'A' and 'B' as well as the other codes for packaging (N/R) and lead-free (Z). The order codes are on the last page. Are there other special grades?


----------



## leeperry

I think the diff between A and B is the same as between the LT1469-1 and LT1469-2, -2 is faster but requires a gain of 2 or more...so I think AD797A will be more "universal" than B 
	

	
	
		
		

		
		
	


	




 ahhh, these datasheets are giving me headaches 
	

	
	
		
		

		
		
	


	




 and anyway I think I love the LT1358IN8, I don't wanna lose my sanity in all that op-amp mumbo jumbo 
	

	
	
		
		

		
		
	


	




 I believe I need the gain bandwidth to be as low as possible(nothing more than 30Mhz or so, considering the stock 2114D were 15Mhz, and that my soundcard has crappy sockets), and unity gain stable at 1(not the case of the AD797B 
	

	
	
		
		

		
		
	


	




)


----------



## majkel

You don't read carefully, guys. 
	

	
	
		
		

		
		
	


	




 It's a minimum *open loop* gain which is a strictly op-amp parameter, not a circuit parameter. The higher, the better. Just look, it's V/uV which means minimum is 1,000,000 and 2,000,000 V/V respectively. 'B' series is suitable for unity gains, too.


----------



## Apocalypsee

Guys, I would like some opinion, I just bought X-Fi Elite Pro, the stock sound is excellent, but only a bit muddy because stock caps and opamp, but I do have some spare opamp to replaced, which is LME49720, LME49723 (slightly worse than the former), LT1364. Which one is the best choice?


----------



## ROBSCIX

Quote:


  Originally Posted by *Apocalypsee* /img/forum/go_quote.gif 
_Guys, I would like some opinion, I just bought X-Fi Elite Pro, the stock sound is excellent, but only a bit muddy because stock caps and opamp, but I do have some spare opamp to replaced, which is LME49720, LME49723 (slightly worse than the former), LT1364. Which one is the best choice?_

 

With that card many have been using the LM4562MA for upgrading the circuit,
 The LME49720 you have are the same unit. Those opamps should give you a noticable upgrade in sound quality.


----------



## SpudHarris

I have been doing this all wrong for ages 
	

	
	
		
		

		
		
	


	




 and I've only just found out. I have a Ibasso P3 & P3+ and never thought to put the supplied dummy adapters in the ground channels on either one. I did this a few nights back and realise I haven't been purely listening to the actual opamps in L/R as the ground channel adds something.

 The upshot is I am loving opamps that I never really rated before because for want of a better word their sound was 'tainted' by what ever was in ground or Virtual Ground (usually AD797's). Now don't get me wrong there are a few opamps that benefit from the addition of opamps in ground but I'm using the amps without at the moment and for the forseable future.

 Humble pie time for me I'm afraid, one of the finest sounding opamps to my ears NOW is the OPA211 but I also find the LME49722 real nice also. These 2 are my favourites at present. For anyone interested I'm using BUF634's (Hi-C) but no opamps in G/V. More isn't always better!! just took me a while to discover that.


----------



## ROBSCIX

Atleast you figured it out and now you can go back to testing all over again. Sounds like fun to me!

 The OPA211's are nice, if you can try out the LME49710HA's. I am unsure if your application is dual or single channel but the 710HA's are single channel TO-99's.

 The OPA211's are nice though as you said, I have been testing alot latley with a bunch of new opamps I built a couple weeks back.


----------



## diditmyself

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_For anyone interested I'm using BUF634's (Hi-C) but no opamps in G/V. More isn't always better!! just took me a while to discover that._

 

The ground channel really has to be low impedance and an open loop buffer like BUF634 can't make it on it's own. If you find the sound very different from using opamp/buffer you're listening to an erroneous sound now, not before. The lower the impedance of the phones the worse it gets, both crosstalk and distortion.


----------



## SpudHarris

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_The ground channel really has to be low impedance and an open loop buffer like BUF634 can't make it on it's own. If you find the sound very different from using opamp/buffer you're listening to an erroneous sound now, not before. The lower the impedance of the phones the worse it gets, both crosstalk and distortion._

 

I'm not technically qualified to comment on that, I use my ears to tell me what sounds good and what does'nt. All I can say is that I prefer the sound of a lot of my opamps now with dummy adapters in the G and G/V channels of my P3 amps. Don't know if it should sound better but it does. Ibasso despatch the stock P3+ with AD827 in L/R + Transistor Buffers and Dummy Adapters in G/V.


----------



## Cynips

Quote:


  Originally Posted by *fzman* /img/forum/go_quote.gif 
_Google Translatefound these in my web travels, and think they would be interesting for finicky opamps. this is the english translation, if i got it right. any thoughts, help from anyone in sweden re: pricing and availability? reputation of this company??_

 

They seem like a serious business though I haven't had anything to do with them. Hardcore audiophiles if you ask me. For international orders you have to pay the actual shipping cost, whatever that is from Sweden to the US. Pricing seem decent, 1USD = 7.2SEK at the moment, so 35:-, e.g., would be almost $5 but since you don't have to pay Swedish VAT you can deduct 20% off of the price and would end up a buck less. I'd expect shipping costs to be about twice of what you'd pay to send the same thing from the US to Sweden.

 Just ask if you have more questions or need any help with the translation.


----------



## ROBSCIX

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_They seem like a serious business though I haven't had anything to do with them. Hardcore audiophiles if you ask me. For international orders you have to pay the actual shipping cost, whatever that is from Sweden to the US. Pricing seem decent, 1USD = 7.2SEK at the moment, so 35:-, e.g., would be almost $5 but since you don't have to pay Swedish VAT you can deduct 20% off of the price and would end up a buck less. I'd expect shipping costs to be about twice of what you'd pay to send the same thing from the US to Sweden.

 Just ask if you have more questions or need any help with the translation._

 

I am unsure without looking at the design but usually when caps are that close to oapmps, they are not used in a attempt to make the module sound better. 
 They are used to stabalize opamps which are high speed and tend to osciallte. Depending on how the caps are used they can stabalize the opamps in many ways. They can be used to "slow down" the opamp or decouple them from the power as many times the supply can cause oscialltions. I am just guessing though based on a quick look.


----------



## fzman

cynips -- thanks for the offer. i may try to place an order for some soon. perhaps other head-fiers would want some as well.

 robscix -- you are correct, the caps "slots" are for rail to ground and rail to rail decoupling caps, which can both stabilize and "make them sound better". it's much easier, so it would seem, to do it on these boards, if they'll fit, than to hack away at it, and have long leads, and dangling parts --


----------



## ROBSCIX

Yes, I know what they are for. I was just explaining to Cynips as I wasn't sure what he meant by his post.


----------



## Bonthouse

Okay, I've had the AD797A a few days now in my Corda Meier Move and I must say.. I'm in love.

 Lows extend way lower, highs are sparkling, mids are fun to listen to. Detail and speed are very nice and the sound is absolutely not fatiguing
	

	
	
		
		

		
			




 It has a little less detail and speed than the LME49710, but this one makes my head nod, this one has soul! 
 Highly recommended!


----------



## ROBSCIX

I have a AD797A and while I find it a good opamp, it is definately not the end of the road for me.
 If it is a musical amp in your application, that is good. Many opamps might not have the high detail that others have but they get your toe tapping and that is the main thing.


----------



## fzman

guys,

 something i've been trying to find is a comparison between the ad8599 and the ad8022. this would be on browndogs, as the buffer/ diff to single ended opamp on a prodigy hd2 sound card; with opa2604s as low pass (voltage dac akm4396), so it is not i/v.

 i've tried several combos and so far the majkel recommendation of 2 x 2604 and 1 x 8022 sounds very very good. the 8022 is very fast, but is not oscillating, at least so far as the temperature test is concerned. i haven't put it on the scope yet, even though i have one and sorta know how to use it.....

 this combo, as i mentioned above, sounds very good-- very open, good timbres, dynamics, good precise imaging etc.... it does seem to slightly accentuate upper mids - cymbals, etc, and can get just a touch edgy on bad cds.....

 would sustituting the 85999, which i just browndogged, keep the resolution but give it a touch more balance, and that natural glow and coherence???

 please answer in the space provided, and show your work!!! 

 don't you just love a pop quiz


----------



## ROBSCIX

Try it out and let your ears be the judge. 
 The 8599 seem highly regarded among many for audio use. I built a few the other night along with a whole mess of other ones. I create a list and then just sit and build then work on the next list
	

	
	
		
		

		
		
	


	




 My intial test seem very quite promising.


----------



## acvtre

I've found a great ebay opamp and ADs seller and I'm going to buy a bunch of ICs. Do you have something to suggest such as a must-have list?


----------



## SpudHarris

Trade you for his details!


----------



## majkel

@fzman, you can try the OPA2228 instead of the OPA2604. My friend did it and found it as an improvement. The buffer might be the AD8599 or the AD8022. The AD8019 could probably work as the output buffer as well as the AD8397. Everything is to try out.


----------



## Cynips

Quote:


  Originally Posted by *fzman* /img/forum/go_quote.gif 
_cynips -- thanks for the offer. i may try to place an order for some soon. perhaps other head-fiers would want some as well.

 robscix -- you are correct, the caps "slots" are for rail to ground and rail to rail decoupling caps, which can both stabilize and "make them sound better". it's much easier, so it would seem, to do it on these boards, if they'll fit, than to hack away at it, and have long leads, and dangling parts --_

 

Weird, seems all my subscriptions here at head-fi expired 
	

	
	
		
		

		
		
	


	




 Anyway, they write on that page about using these adapters to make things like CD-players sound better. Can't find any reference to stabilization, just that they're using capacitors to decouple the supply voltage (if I'm translating this right). If you really want to know you could try mailing to that guy at the address supplied: sigurd@ruschkowski.se


----------



## ROBSCIX

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_Weird, seems all my subscriptions here at head-fi expired 
	

	
	
		
		

		
		
	


	




 Anyway, they write on that page about using these adapters to make things like CD-players sound better. Can't find any reference to stabilization, just that they're using capacitors to decouple the supply voltage (if I'm translating this right). If you really want to know you could try mailing to that guy at the address supplied: sigurd@ruschkowski.se_

 

I was just commenting on capacitor use in regards to opamps in a general sense. They can be used for stabalizing opamps which are touchy and prone to oscialltion. They are also used for other tasks depending on the design.

 I have seen a few upgrade modules now with caps built into the module. Most are meant for upgrading older CD players as you suggested.


----------



## acvtre

Quote:


  Originally Posted by *acvtre* /img/forum/go_quote.gif 
_I've found a great ebay opamp and ADs seller and I'm going to buy a bunch of ICs. Do you have something to suggest such as a must-have list?_

 

UP!


----------



## ROBSCIX

Quote:


  Originally Posted by *acvtre* /img/forum/go_quote.gif 
_UP!_

 

Many will tell you to avoid Ebay as their have been many cases of fake opamps being sold. Cases of blown opamps being sold....etc...

 I would suggest you find a source with a good reputation and buy form them.


----------



## acvtre

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Many will tell you to avoid Ebay as their have been many cases of fake opamps being sold. Cases of blown opamps being sold....etc...

 I would suggest you find a source with a good reputation and buy form them._

 

No this one is reliable and has got tons of ICs. Which one do you suggest to buy? Do you suggest any seller?


----------



## earthpeople

Hey guys, not sure if this is the right place to post it but thought I would try before making a new thread.

 There are two op amps in my amp and I don't know which one (or both?) I'm supposed to change if I want to change the sound. Here's what's listed on the page I bought it from 
  Quote:


 # OPAMP chip: Burr-Brown OPA2134
 # Headphone AMP: Burr-Brown OPA2604+TIP41C*2+TIP42C*2 (Referencing the SOLO headphone amplifier) 
 

Help please? Thanks!


----------



## ROBSCIX

The 2134 is a dual channel audio ampliifer. You can change that one out.
 The headphone amplifier is a 2604 another audio opamp. You may consider changing that one also. Are these socketed or soldered to the PCB?

 If they are soldered in, you may consider removing the chips and replacing them with high quality machined IC sockets. This way you can test whever you want. _just snap them into the sockets.


----------



## earthpeople

Alright, thanks. I have a AD8620 that I want to try putting in there, just didn't know which one would be the right one and I didn't want to put it in the wrong spot and maybe cause problems.

 They are in sockets already, which is pretty cool. Makes for easy swapping.


----------



## SpudHarris

Is your AD8620 (SOIC) already soldered onto a DIP adapter like this? If not then it needs to be before you can use it.

 By the way the AD8620 is a beautiful OpAmp.


----------



## earthpeople

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Is your AD8620 (SOIC) already soldered onto a DIP adapter like this? If not then it needs to be before you can use it.

 By the way the AD8620 is a beautiful OpAmp._

 

Yep, I actually ran into that issue when I first bought it. Then I bought a BrownDog adapter and soldered it together and used it in my XM4 for a while.


----------



## 12Bass

Before swapping opamps, I'd suggest checking the supply voltage to make sure that it is not above the recommendations. Some chips (like the AD8620) cannot take +/-15V rails.


----------



## earthpeople

Would that just be what it says for output on the power plug? This one says output is DC15V 1000mA. So direct current 15V would be too high for the AD8620?


----------



## ericj

ad8620 can handle up to 24v but a lot of people say it starts to sound thin above about 20v. 

 Also, an unregulated 15v 1A supply is likely putting out close to 24v unloaded.


----------



## earthpeople

Hm, I measured it and it came out to 23.7V

 So, let's say I get a regulated power supply for this. The amp says for input "DC 12-18V". Should I go for the higher end of that or closer to 12V? Or should I not even bother getting a new PS?

 I really appreciate the help with this guys.


----------



## murrays

Quote:


  Originally Posted by *squid+* /img/forum/go_quote.gif 
_Hm, I measured it and it came out to 23.7V

 So, let's say I get a regulated power supply for this. The amp says for input "DC 12-18V". Should I go for the higher end of that or closer to 12V? Or should I not even bother getting a new PS?

 I really appreciate the help with this guys._

 

The input voltage to the amp may not be what gets fed to the op amp chips. It is possible (and preferable) that there is some voltage regulation before it gets to the chip. This will reduce the voltage by a bit. You can only be sure by checking the Power supply voltage pins in the op amp itself.


----------



## ROBSCIX

The input voltage will be sent through rectifiers, regulators and ripple/noise surpression circuits first so you can send in 16V or 23V....it comes out the same. -whichever voltage the designers wanted. -most likley 12/15..but that is a guess.

 Measure the supply pins of the opamp. This will tell you exactly what the opamps are being supplied with.


----------



## ROBSCIX

I should have a whole shipment of new adapters very soon. I have a few new items I want to build. Dual AD8610's...Dual THS4031, more dual LME49710's...along with quite a few others. I do a build from myself and freinds about every 60 days. My build lists seem to get bigger everytime...


----------



## Cynips

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I should have a whole shipment of new adapters very soon. I have a few new items I want to build. Dual AD8610's...Dual THS4031, more dual LME49710's...along with quite a few others. I do a build from myself and freinds about every 60 days. My build lists seem to get bigger everytime..._

 

I'm taking two weeks of vacation right now, but I'll be at home the first week. Concentrating on catching up on all the new music rather than opamp rolling. We'll see if I feel up to some soldering or if I'll just plain enjoy the tropical heat that's been building up the last couple of days


----------



## ROBSCIX

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_I'm taking two weeks of vacation right now, but I'll be at home the first week. Concentrating on catching up on all the new music rather than opamp rolling. We'll see if I feel up to some soldering or if I'll just plain enjoy the tropical heat that's been building up the last couple of days 
	

	
	
		
		

		
		
	


	


_

 

Enjoy your vacation.
 I opamp roll as I am catching up on music. I will let you know how the testing goes.


----------



## acvtre

Do you have any opamp seller to suggest and some must-have opamps?


----------



## earthpeople

Sorry to bring the thread back to me and my lack of knowledge, but I opened it up and checked the voltage of the power pin sockets and it gave me 20.9V for both op amp sockets. I'm not sure where to go with this now. Should I even change anything then?

 Another question, what is the reason for having multiple op amps? I'm a little confused on that.


----------



## 12Bass

Is that 20.9V across pins 4 and 8? If so, that means that you can use replacement chips with up to a 21V maximum supply voltage... many can take 24V or more. Lots the the "mainstream" opamps are rated at 34 - 36V.


----------



## earthpeople

Yes, pins 4 and 8. So I don't have to worry about swapping in an op amp and breaking it or anything hm? Great, thanks!


----------



## ROBSCIX

Just check the voltages on the spec sheet. As was mentioned many mainstream opamps use higher voltages then what you have there.

 As for the purpose of multiple opamps, they can be doing different jobs. They can be converting current to Voltage, buffering a signal or filtering...etc. There are many tasks those chips can perform.


----------



## ROBSCIX

I was wondering what units everybody is currently testing out.
 Latley I have been working with a dual LME49710 and a dual OPA827 module.
 I am waiting for some new stock to build some new modules....


----------



## SpudHarris

Well I've just rediscovered the AD8610's that I had for ages in my PPAv2 and forgot how good they were. I've also been messing about with different buffers (634's) i.e. Hi-C, Stacked and Hi-C + Stacked. The stacked buffers in the P3+ really make the AD8610's sound superb,probably not the most natural combination but dynamic, fast and real resolution. Listening to Phutureprimative with this set up makes the hairs on my neck stand on end!!


----------



## ROBSCIX

You reminded me I want to build some AD8610 modules. I have a few 8620's but I want to build some dual 8610 modules. AD seems to have many nice opamps that are recommended for audio all the time.


----------



## ROBSCIX

I wouldn't say the AD8620 is mediocre especially when compared to a 2132.
 I guess circuit and personal taste play alot into your opinion though.


----------



## SpudHarris

X2 

 mmmmmm, wonder who that is singing the praises of that 2132? 

 The AD8620/8610's smoke that chip *and then some *in every amp/circuit I've ever rolled with. I've even gone back to it numerous times to see if I've missed something but I come to the same conclusion every time ''medeocre!!''


----------



## NotoriousBIG_PJ

I've got the ad826 opamp in my compass right now. The highs are harsh and the midrange is blanketed with a warmth that takes away from the clarity I've heard with a lot of the other opamps I have on hand. It is certainly an interesting sounding opamp. Almost makes my hf-2's go from sounding like baby ps-1's to rs-1's.

 Biggie.


----------



## ROBSCIX

..Maybe we have another Alias for a banned member?


----------



## fzman

speaking of opamps, and hopefully not too far off topic, who here has built either a cmoy and/or a mini-3, and how do they sound. is the mini3 better than a cmoy, and what are people's favorite opamps for the cmoy. both of my diy headphone amps are one-offs, and i have never tried a mini3 or a cmoy.

 i've got an amp3, which sounds good, but i have no basis for comparison in the world of portable amps. (Would be used with a toshiba gigabeat f40 and shure e4cs or denon c700s.....

 thanks!

 mark

 also, crusing with the majkel recommended 2 x 2604 and single 8022 in my poridgy sound card -- yum!

 waiting for the enegery to sub the 8599 for the 8022, but no one sems to want to comment on the differences between the 8022 and the 8599


----------



## mkanna

I'm a new poster, so I'd like to start by thanking all of you on this thread, and the Audio-gd OpAmps thread. I tested 8 different opamps about a year ago, and ended up with an ad 826 in my diy battery powered Elliot Sound Products preamp. After reading these threads I got some LME49862's, and it is waaaay better. I can be kind of cynical sometimes, and I didn't really think it would make that much difference, so thanks for the excellent addition to my system. I have LME49720 and LME49860's on the way, btw.
 Thanks again!


----------



## leeperry

I've received my OPA2277P samples, apparently they're pretty good!


----------



## mkanna

I got an Assemblage 2 Dac recently, and it sounds good. It is the upgraded version, but the opamps might be improved on. Coming out of the pcm1702 dac, the AD811an do the I/V conversion, and then AD817an's do filtering duty. What would be an upgrade for either pair? I should mention it will
 go into a Elliot sound products preamp board. The esp circuit has one gain stage, LME49862 (which soon may be replaced by a LME49720ha). I hope this isn't too off topic, but this thread has the best info I could find.


----------



## SpudHarris

Quote:


  Originally Posted by *fzman* /img/forum/go_quote.gif 
_speaking of opamps, and hopefully not too far off topic, who here has built either a cmoy and/or a mini-3, and how do they sound. is the mini3 better than a cmoy, and what are people's favorite opamps for the cmoy. both of my diy headphone amps are one-offs, and i have never tried a mini3 or a cmoy._

 

I've built and sold a few of each. The mini3 uses SOIC opamps directly to the pcb so unless you are real handy with a soldering iron you can forget rolling. I believe anyhow that the mini3 circuit was designed around the AD8397 so rolling would probably cause problems. Cmoys vary depending on components used and wether you go breadboard or buy a ready made pcb. If you are interesed I still have some JDS Labs pcb's and various components (actively built them for a while). As long as you decouple you can roll almost any opamp in these and get a flavour for your likes/dislikes.

 Either that or get a P3 or P3+ from ibasso, they even come with a rolling kit consisting of a few of the ''well knowns''.


----------



## SpudHarris

Quote:


  Originally Posted by *C§H* /img/forum/go_quote.gif 
_Well, *I really like the LME49860*, but it sounds identical to the 2 LME49710 in the other DAC. 
	

	
	
		
		

		
			






 Anyway, *this is good sound indeed*. So its one between LME49860 and (more probably) OPA211ID for me. The others are not worth it, when these exist._

 

mmmmmmmm...... and now it is *sad tonal colour*? Did anyone go and get the LME49860? You will have to send it back as Andrea has changed his mind


----------



## LuciferX

Diferences in bass/mediums/highs , quality, "type of sound" etc of this?:

 OPA2132

 LME49860

 LM4562

 LME49720NA

 LT1361CN8

 Im planning use them in this soundcard: HT Omega - Claro halo XT Factory installed opamps are 4580 (JRC). Claro halo use 12V for power supply voltage to opamp.

 And read this please, is the "design" of the Claro Halo: HT Omega

 PD: Sorry for my english


----------



## LuciferX

Quote:


  Originally Posted by *sancho* /img/forum/go_quote.gif 
_OPA2132*P*: smooth, coherent, full, relatively warm, smooth treble

 LME49860: "digital", audiophile if you will, it bores me

 LM4562: roughly the same as the above

 LME49720NA: roughly the same as the above

 LT1361CN8: musical, present midrange, slightly dry

 LT1355CN8: smoother, musical, neutral -> my favorite of the list_

 

And in a "combo configuration", what do you suggest ?

 The soundcard use 4 dual opamps: 






HT Omega

*The each polarity signal produced by AK4396 goes to 2 dual opamps (U8 for left, U10 for right) In those dual opamps, each opamp handles only one polarity, either positive signal or negative. Then both exclusively amplified positive and negative signals are re-assembled and goes to another opamps (U9 for left, U11 for right) for second amplification. In the second dual opamp, U9, The one opamp is for left headphone and the other is for left RCA output. In U11, one opamp is for right headphone and the other is for right RCA output.


 This design maximizes the feature of AK4396DAC and it also dramatically improves stereo-talk.

 It is recommended to swap all four opamps for your preferred analog sound
 color. Factory installed opamps are 4580 (JRC).

 If you choose to swap only two, they must be U8 & U10 ( They are marked on PCB of Claro halo)*


----------



## leeperry

Quote:


  Originally Posted by *sancho* /img/forum/go_quote.gif 
_OPA2132*P*: smooth, coherent, full, relatively warm, smooth treble

 LME49860: "digital", audiophile if you will, it bores me

 LM4562: roughly the same as the above

 LME49720NA: roughly the same as the above

 LT1361CN8: musical, present midrange, slightly dry

 LT1355CN8: smoother, musical, neutral -> my favorite of the list_

 

haha, you change your mind every day 
	

	
	
		
		

		
		
	


	




 good thing I've received my LT1355CN8 samples, but they don't seem too willing to send me the LT1057ACN8...but well it takes +3 weeks to get them, so maybe they'll show up someday 
	

	
	
		
		

		
		
	


	




 and I also got my OPA2132P 
	

	
	
		
		

		
		
	


	




 I loved the LT1358IN8 anyway, the same w/ a bit less dark trebles would be great...they sounded good but a tiny bit muffled, maybe...I dunno, need to use them on a longer run!

 but as you said it's hard to get a perfect balance, and it's prolly better if the trebles are a bit dark(like the 49720HA/LT1358IN8) than whining(like the 49720NA)


----------



## leeperry

oh sure, there's the "new toy syndrome" and also the brain(and possibly op-amp) burn-in....plus the native FR of your gear.

 Ideally, if I could find some op-amps that kills 2 bands at 6.4KHz/10KHz...this would kill some of my outer ear resonances w/ headphones, and I wouldn't need to EQ anymore 
	

	
	
		
		

		
		
	


	




 I wish they'd make some "smart" op-amps, w/ a custom EQ range....but well, that doesn't sound too feasable anyway


----------



## crapback

I swear I should feel bad for ordering the 50 or so opamp samples today. I'm blaming you leeperry, for that brief moment of guilt that just passed by. 
	

	
	
		
		

		
		
	


	




 I'm not going to get any calls from salesmen am I? 

 Before I read this thread and found out about getting free samples I spent $20 on 4 4562's. I put a pair in a gigawork dac to replace the stock 5532's and it has made a great improvement in both the soundstage and it has tamed the overpowering bass it initially had. I had read up on opamp rolling in a zero dac thread and the 4562's are supposed to sound good in it with the 627's so I got some for my 09 zero that should be delivered soon. 

 Thanks leeperry for the "low cost" upgrades. I just hope I don't start getting sales calls.


----------



## leeperry

haha, it's my fault now! 
	

	
	
		
		

		
		
	


	




 don't forget to share your impressions 
	

	
	
		
		

		
		
	


	




 well, TI has sent me a lot of samples...but I bought a Darkchip3 DLP projector from Mitsubishi a few years back, for a healthy lot of cash...so I've put money in the basket!


----------



## LuciferX

If i request samples to Argentina ... i have to pay something? Sorry, im just new in this thing


----------



## leeperry

dude, why do you really wanna put your money in that HT Omega card? its IMD measurements are terrible, even worse than the Realtek mobo chips! and god knows if they'll still exist in a few years, and without drivers you won't go very far.

 anyway, your money your choice.

 samples are free, even if you live in Zimbabwe or in the North Pole.


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I've received my OPA2277P samples, apparently they're pretty good!_

 

Hey, have you had chance to try these yet? I know you have a few samples to get through but wondered if they were the next big thing?? I am really liking the LT1124 at the moment it is real nice............


----------



## leeperry

LT1124? where did you pull this one out from? 
	

	
	
		
		

		
		
	


	




 well, my soundcard is still in RMA(one faulty DIP8 socket) hopefully I should get a replacement early next week.......so for the time being I'm just hoarding op-amps hoping for a better day


----------



## LuciferX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_dude, why do you really wanna put your money in that HT Omega card? its IMD measurements are terrible, even worse than the Realtek mobo chips! and god knows if they'll still exist in a few years, and without drivers you won't go very far.

 anyway, your money your choice.

 samples are free, even if you live in Zimbabwe or in the North Pole._

 

The email support is fantastic, they have drivers for windows 7 ... and i need a card with 7.1 (analogs) AND headphones AMP (The asus essence ST never comes .... and if is launched soon, the daughter card with analogs not ...)

 Everybody i know that have the claro halo is happy, so, why not?

 PD: IMD <<< this can be improved using news opamps?


----------



## leeperry

you can very slightly improve THD+N and SNR by rolling op-amps, but not IMD. well, these days any soundcard will make you happy...especially if you have nothing to compare it against. still this card gives worse IMD measurements than a $2 Realtek mobo chip, whether this is acceptable is your choice...and it's OT in this thread anyway


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_LT1124?_

 

Well after receiving my P3+ I was crying in my beer because I couldn't use my beloved OPA637's in it. Ryuzoh who is working on the P3 OEM project with ibasso recommended the LT1124 (along with the LT1357's and 1468's) as ''Fast & Detailed'' alternatives. Personally the 1468's do nothing for me but the 1357's and the 1124 especially are real sweeeeeet. 

 You not heard much about that one??


----------



## leeperry

hah, ok 
	

	
	
		
		

		
		
	


	




 well I've just ordered some samples of it, if I get them mid september I'll be lucky.

 anyway, my replacement soundcard should ship tomorrow....I'll let it burn-in a little while w/ the stock 2114 op-amps, it seems to matter as I was getting funky noise w/ the 49720NA when the card was brand new unused 
	

	
	
		
		

		
		
	


	




 and I dunno, I've got so many samples now 
	

	
	
		
		

		
		
	


	




 I might try the 2132 or the 1355, or if I'm lucky the 1057 will show up in the meantime.

 I also got a whole bunch of browndog's I gotta send my friend so he puts 49722/OPA211/THS4031/LT1028 on them


----------



## fzman

Nigel, thanks! i guess i was trying to get a sense of how good they can sound, and what they would compete against in the "off the rack" world. i would not be doing the mini 3 to roll opamps in, just to carry around. is it better than a cmoy- or can the cmoy be tweaked out to be better?

 what I've figured out so far is that the gigabeat sounds better amped, by the amp3, and better thru the dock's line out than thru the headphone out into the amp3.

 the competition is the amp3. would probably not buy another built amp, but may build a cmoy or mini 3 if they sound really really good....

 cans are shure e4c, the buds tha came with the amp 3 (yuins, i believe), and denon c700s. i may also get the shure 840s, which sound really good and are easy to drive. my taste is for natural tonality and not artificial hi-fi detail from a tipped up treble, or sucked out midrange.

 best,

 Mark

  Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I've built and sold a few of each. The mini3 uses SOIC opamps directly to the pcb so unless you are real handy with a soldering iron you can forget rolling. I believe anyhow that the mini3 circuit was designed around the AD8397 so rolling would probably cause problems. Cmoys vary depending on components used and wether you go breadboard or buy a ready made pcb. If you are interesed I still have some JDS Labs pcb's and various components (actively built them for a while). As long as you decouple you can roll almost any opamp in these and get a flavour for your likes/dislikes.

 Either that or get a P3 or P3+ from ibasso, they even come with a rolling kit consisting of a few of the ''well knowns''._


----------



## crapback

Darn this site straight to heck i say!!! I really need to start smoking crack so I can have an affordable addiction. I'm having way too much fun learning all about everything head-fi though so it's worth it, I think.

 I'll definitely keep you informed about my impressions of all the new opamps. I just spent more on all the cable and parts to build some knockoff cardas cables for my 650's and 990's so hopefully that will only add to the fun. It's definitely not adding anything to my bank account. 

 I only have the dac in my predator to compare this gigawork dac to but so far I'm pretty impressed. The dac's not burned in yet but my predator has about 300 hours on it so it's only getting better. The predator was my first real dac and it revealed things in my music that I've never heard. The $140 gigawork dac is even more revealing than the predator's, something I never expected for that price. The 4562's opened things up even more so I'm dying to get my hands on some better opamps. I need to be patient though and let the thing burn in. Here's a link to the thing Gigawork 24/192 Up-sampling DAC DA CONVERTER w/ USB kit - eBay (item 120449848730 end time Jul-26-09 09:43:33 PDT). I guess majkel did some mods to the older version and said it sounded pretty sweet so I bought one and I'm glad I did. If I could only find a case to put it in that's not too big.

 Here I go rambling on... Just a quick question for any of you knowledgable folks. Are there incompatible opamps that can cause damage or fry other components when you put them in? Some other noob may have asked this already and I just missed it cause I've been reading so much here lately. 

 Thanks, Joel


 I just double checked that ebay link and it is now showing the old version. It had the pics of the new red pcb and the better caps.


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_Ideally, if I could find some op-amps that kills 2 bands at 6.4KHz/10KHz...this would kill some of my outer ear resonances w/ headphones, and I wouldn't need to EQ anymore 
	

	
	
		
		

		
		
	


	




 I wish they'd make some "smart" op-amps, w/ a custom EQ range....but well, that doesn't sound too feasable anyway 
	

	
	
		
		

		
		
	


	


_

 

Surely an op amp with such a poor frequency response would be defective! The op amp is a generic building block around which a circuit is designed. What you describe is a bandpass/stop filter. There are many circuits based around op amps to implement such EQ if you desire. It just requires some resistors + capacitors + math.


----------



## leeperry

hehe, ok got it! but they make pretty big discrete op-amps....why not one w/ a custom EQ? coz right one we're doing some major hit & miss in the hope that we'll like the chip FR 
	

	
	
		
		

		
		
	


	




 anyway I've just received my OPA132 and my replacement soundcard has been shipped yesterday 
	

	
	
		
		

		
		
	


	




 my OPA827 have been back-ordered until the end of Sept. and my LT1028 are still not coming, so maybe I'll pass them.


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_my OPA827 have been back-ordered until the end of Sept. and my LT1028 are still not coming, so maybe I'll pass them._

 

I am interested to know how the OPA827 goes for you, as am planning on upgrading my OPA2134 with a couple of those. On the other hand, I know your opinion of my Pro750's - so maybe you will hear different results to me.


----------



## leeperry

haha yeah, Pro750: the worst headphones in the history of mankind 
	

	
	
		
		

		
		
	


	




 well, did you try the 1358/1057?


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_haha yeah, Pro750: the worst headphones in the history of mankind 
	

	
	
		
		

		
		
	


	




 well, did you try the 1358/1057?_

 

No op amp changes yet - I am still doggedly tracking down sources of spurious noise. I want to get all the basics sorted before moving on. I don't hear changes as easily as many others seem too, but I am expecting a change from a cheap op amp, that most find mediocre, to a top-spec one to be a step up.


----------



## SpudHarris

Quote:


  Originally Posted by *fzman* /img/forum/go_quote.gif 
_Nigel, thanks! i guess i was trying to get a sense of how good they can sound, and what they would compete against in the "off the rack" world. i would not be doing the mini 3 to roll opamps in, just to carry around. is it better than a cmoy- or can the cmoy be tweaked out to be better?

 what I've figured out so far is that the gigabeat sounds better amped, by the amp3, and better thru the dock's line out than thru the headphone out into the amp3.

 the competition is the amp3. would probably not buy another built amp, but may build a cmoy or mini 3 if they sound really really good....

 cans are shure e4c, the buds tha came with the amp 3 (yuins, i believe), and denon c700s. i may also get the shure 840s, which sound really good and are easy to drive. my taste is for natural tonality and not artificial hi-fi detail from a tipped up treble, or sucked out midrange.

 best,

 Mark_

 

The mini3 is a great sounding little amp no doubt and would probably blow most (not all) cmoys out of the water. This is the best sounding cmoy there is IMHO. I've owned one for ages and it is superb. I've put mine in an Altoids Tin as the enclosure is a bit bulky/heavy, I sold my mini3 after getting this. Oh and you can roll opamps if you so desire.


----------



## acvtre

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_hah, ok 
	

	
	
		
		

		
		
	


	




 well I've just ordered some samples of it, if I get them mid september I'll be lucky.

 anyway, my replacement soundcard should ship tomorrow....I'll let it burn-in a little while w/ the stock 2114 op-amps, it seems to matter as I was getting funky noise w/ the 49720NA when the card was brand new unused 
	

	
	
		
		

		
		
	


	




 and I dunno, I've got so many samples now 
	

	
	
		
		

		
		
	


	




 I might try the 2132 or the 1355, or if I'm lucky the 1057 will show up in the meantime.

 I also got a whole bunch of browndog's I gotta send my friend so he puts 49722/OPA211/THS4031/LT1028 on them 
	

	
	
		
		

		
		
	


	


_

 

Where did you get it? I'm interested.


----------



## Bobobear

can anyone recommend me opamps that fit into a auzentech x-raider and has a sound signature for trance music. i will be using the soundcard with my ad700 (in the process of shipping). right now the sound card has 4 slots all filled with stock TI NE5532P or NE5532A (one of those two). 

Auzentech, Inc. : X-Raider 7.1 : World First soundcards for Music, HTPC, and Gaming.

 this is actually my first sound card and its a pretty cheap one so i'm not sure what to expect with opamp change.


----------



## 12Bass

Compared with the OPA2134 I've found the OPA827 to be more open and natural, resolving, though still somewhat warm. IMO, the OPA2134 is sort of "phasey" and veiled.


----------



## Bobobear

anyone got recommendations because i just registered on texas instrument and they have free samples. so if you can, just name a few known good opamps that work on my sound card and i'm gonna try to get a sample of them to try.


----------



## ROBSCIX

Yes the OPA827's would be a good one to try BUT, they are single channel and surface mount so you would need a adapter and two for each module you build.


----------



## Bobobear

do i have to pay tax,duty , broker fee for these free samples?


----------



## Bobobear

i also received a confirmation number, what is this for?


----------



## 12Bass

From the manufacturer's pictures it looks like the X-Raider uses NE5532s. Some possible suggestions are LM4562/LME49720 and OPA2211A (on adapter). IME, the OPA2211A sounds a bit more open and "organic", while the LM/LME parts are a bit more sterile and maybe a tad thin in the bass.


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Yes the OPA827's would be a good one to try BUT, they are single channel and surface mount so you would need a adapter and two for each module you build._

 

Also note these are backordered until mid-late September (waiting for my samples). Personal favourites (dual) are: LME49722 / OPA2111 / AD8620 / LT1124.


----------



## murrays

Quote:


  Originally Posted by *Bobobear* /img/forum/go_quote.gif 
_can anyone recommend me opamps that fit into a auzentech x-raider and has a sound signature for trance music. i will be using the soundcard with my ad700 (in the process of shipping). right now the sound card has 4 slots all filled with stock TI NE5532P or NE5532A (one of those two). 

 this is actually my first sound card and its a pretty cheap one so i'm not sure what to expect with opamp change._

 

You may be expecting too much from just an opamp change. Opamps are not designed to have different "sound signatures" - that is just a subtle side effect of their functioning within a specific circuit. You would be best to search for people with the same sound card and find what they have experienced in this respect.

 If you are not happy with the sound quality from your new sound card and headphones then you must consider each part of the audio chain. Usually you have to have everything pretty well "right" before moving to such tweaks.

 There is a possibility that changing to a "better" op amp may just reveal more noise and distortion that the "cheap" chip was originally chosen by the designer to mask.


----------



## murrays

Quote:


  Originally Posted by *commodoro* /img/forum/go_quote.gif 
_You know - soo many "audiophile" things are designed with transparency in mind, and none is up to the pretense. Everything has a peculiar character, and opamps, small and all identical as they may seem, are an obvious proof of it..._

 

Yes, I agree with you. Some small things can make a big difference. Sometimes it is hard to know why. My point was to discredit switching opamps as a panacea. Without the experience of others (preferably with the same sound card) there is a long path of experimentation to be trod.


----------



## 12Bass

Quote:


  Originally Posted by *commodoro* /img/forum/go_quote.gif 
_What is the E of IME? 
	

	
	
		
		

		
			






 Anyway... the OPA2211A is a bit more open and sterile to me. The LM4562 is for who favors the warm colors, the LME49860 for an equal (well, more or less) treatment of all sonic colors, and the LME49720 for those who like a slightly shady sound._

 

IME = in my experience

 Difficult to put sound into words..... when I say that the LM4562 sounds more sterile, it is because it seems to have less "life" to it as in it somewhat compresses the dynamics and sounds a bit artificial. IMO, the OPA211/OPA2211A sound more "real" and seem to add less coloration.

 Not much to say about synesthesia/numerology.... 
	

	
	
		
		

		
		
	


	




 And I agree that opamps are not the be/end all for sound. Often they represent only a small contribution to the overall tonality of a given device.


----------



## SpudHarris

Quote:


  Originally Posted by *commodoro* /img/forum/go_quote.gif 
_But my favorite seems to be the more tonally transparent (than both the above) LME49860. 
	

	
	
		
		

		
		
	


	




 The LME49860 is more resolving than the LM4562 too, IME._

 

Oh brother............ when you were someone else a few pages back you described that chip with *''sad tonal colour''* and a few pages before when you were someone else again it was the best thing since sliced bread.

 Just sayin' 
	

	
	
		
		

		
		
	


	




 Must be confusing being all these different people eh?


----------



## SpudHarris

Just finished soldering 2 x ADA4898-1 & 2 x LME49710 (TO-99) and a OPA2211.

 Got some testing to do this evening


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Just finished soldering 2 x ADA4898-1 & 2 x LME49710 (TO-99) and a OPA2211.

 Got some testing to do this evening 
	

	
	
		
		

		
		
	


	


_

 

I soldered up some Dual LME49710HA's awhile back and they are a great little unit. I haven't tried that AD model yet....another unit to add to my already large collection
	

	
	
		
		

		
		
	


	



 Post your results.


----------



## crapback

National Semiconductor won't send me any free samples and they want to charge me more than DigiKey for the stuff. Oh well. Out of frustration I just went and hit up TI and LT for a bunch more samples. I think I should feel guilty considering I'm basically stocking up on enough opamps to last me a dozen dac/amps. Stupid audiocrack...


----------



## Bobobear

my free samples are coming from TI. just got a mail today 
	

	
	
		
		

		
		
	


	




.


----------



## Bobobear

any known opamps from linear tech? i'm gonna hit them up for free stuff too.


----------



## crapback

So far this is what i've hit linear up for. I know there are a lot of posts to read thru in this thread but there is a lot of good info in here. These are the models used by some of the guys here who know what they are doing. 

 LT1352CN8#PBF (Qty: 2)
 LT1355CN8#PBF (Qty: 2)
 LT1364CN8#PBF (Qty: 2)
 LT1469CN8#PBF (Qty: 2)
 LT1028ACN8#PBF (Qty: 2)
 LT1028CS8#PBF (Qty: 2)
 LT1057ACN8#PBF (Qty: 2)
 LT1057IS8#PBF (Qty: 2)

 Add to that list
 LT1357CN8#PBF (Qty: 2)
 LT1357CS8#PBF (Qty: 2)
 LT1358IN8#PBF (Qty: 2)
 LT1358IS8#PBF (Qty: 2)


----------



## murrays

Quote:


  Originally Posted by *commodoro* /img/forum/go_quote.gif 
_The LME49720HA didn't sound like a very coherent opamp to me. Pity because the tonality was quite nice. Perhaps the LM4562HA...

 My favorite LTs so far are the LT1028, LT1355 and LT1358. 

 There are also the LT1055 and LT1056, kind of single versions of the FET-input LT1057 (actually the LT1056 is better)._

 

What circuit are you trying these in? Are the op amp outputs buffered? What sort of power bypassing are you using (i.e. what arrangement and selection of capacitors)? I have found that I really sometimes need to go against the grain and add a couple of small value ceramics to stabilise the circuit.


----------



## acvtre

Does anybody know a good shop where to buy all kind of opamps and can also suggest me a bunch of really good ones?


----------



## SpudHarris

Quote:


  Originally Posted by *acvtre* /img/forum/go_quote.gif 
_Does anybody know a good shop where to buy all kind of opamps and can also suggest me a bunch of really good ones?_

 

Unless you know 100% for sure they are genuine I'd steer clear of e-bay, there are some great guys on there but there are also some rogues.

 Myself? I use Farnell for the most as they always deliver next day, I'm impatient so don't like waiting for stuff. But if you have access to Mouser, Digikey or RS Components you will not go far wrong.

 As for the 'must haves' well, different circuits will effect how they perform and I'm not qualified to comment there. But I do have a huge collection so know what sounds good to my ears.

 OPA637 (Single)*
 OPA627 (Single)
 LME49722 (Dual)*
 LME49710 (Single)* Get the metal can version....
 LT1028 (Single)
 AD843 (Single)
 ADA4898-1 (Single)
 OPA211 (Single)* or OPA2211 (Dual)*
 LT1124 (Dual)*
 AD823 (Dual)
 AD797 (Single)

 The ones with * are what I consider my favourites (for now). These are my opinions, we all have different ears, circuits, phones and musical tastes so what suits one may not suit another. Just for the record though, I mainly use a PPAv2 or an Ibasso P3+ amp, Denon AH-D2000's and W3's and musical taste is Psychill, Psydub, IDM etc. Shpongle, Ott, Younger Brother, Dymons, Slack Baba, Snakestyle, Terre Nine and so on.

 Hope that helps.

 Nigel


----------



## SpudHarris

Quote:


  Originally Posted by *commodoro* /img/forum/go_quote.gif 
_Must have? OPA2211 LME49860 LT1028 AD8599_

 

Agreed with the exception of the AD8599 but only because I haven't got or tried that one, how would you describe it or even better compare it to the OPA2211 which is one of my favourites.


----------



## ROBSCIX

I think the AD8599 is a must have along with a AD8620BR...

 SPud has me interested in the ADA4898-1


----------



## SpudHarris

Haha, yep they are real nice. I stumbled over a seller on e-bay, he's in the US and he's having a clear out. I don't know how much they retail for but I paid $5 for the two. He's got loads of stuff not listed on e-bay and all the real deal, got my 49710's (TO-99) off him also. Do you want me to hook you up? I'm waiting for a mail back reference the AD8599 so I can ask if he's got any left.

 Does anyone have experience of the LME49713 (TO-99)?


----------



## fzman

spud -- the 49713 is a current feedback opamp -- it would not be a drop-in replacement for any of the duals you are used to, although it is a dual.

 it slews at 18800v/us, and is a bitch to work with. i use them in my diy headphone amp, and had help from a member of the National team who developed the lme chips


----------



## SpudHarris

Ah, thanks for that..... Just that I noticed the ones for sale were TO-99 and since getting the LME49710's I've got a thing about those sexy metal cans


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Ah, thanks for that..... Just that I noticed the ones for sale were TO-99 and since getting the LME49710's I've got a thing about those sexy metal cans 
	

	
	
		
		

		
		
	


	


_

 

I have worked a great deal with the LME49710HA, I built a few dual channel modules and find they sound better then the 720's - Whats your opinions on that?
 I have been researching a few different TO-99 for some new modules I want to build.


----------



## Pluto2

Hi Nigel, What would you say about ADA4898-1 vs. opa2211 or LME49XXX, and the LTs?


----------



## SpudHarris

I haven't spent enough time with the ADA4898-1 really. They came at the same time as the metal can 49710's, I soldered them all at the same time but the 49710 went 1st and I like them so much that I haven't taken them out for any period yet. Don't really know if it's placebo but to my ears the TO-99 version sounds cleaner, at this point in time I think they are just perfect in my P3+ with Hi-C Buffers and bypassed G/V.

 Untill I got the 49710's the OPA211's were my favourites. I haven't tried the OPA2211 but think I know what to expect there, I just got it for a cmoy.


----------



## crapback

Quote:


  Originally Posted by *fzman* /img/forum/go_quote.gif 
_spud -- the 49713 is a current feedback opamp -- it would not be a drop-in replacement for any of the duals you are used to, although it is a dual.

 it slews at 18800v/us, and is a bitch to work with. i use them in my diy headphone amp, and had help from a member of the National team who developed the lme chips_

 

I'm new at this so should I be looking for just voltage feedback opamps? What about fet input opamps? I have grabbed a bunch of freebie current feedback opamps cause I was getting a little greedy last night at TI and LT's expense. I've grabbed about every one of the opamps mentioned so far made by Ti and LT. Any advice is greatly appreciated.

 thanks, joel


----------



## murrays

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I'm new at this so should I be looking for just voltage feedback opamps? What about fet input opamps? 
 [snip]
 Any advice is greatly appreciated.
 thanks, joel_

 

Heh, where do we start? You are best to replace like with like.
 You would gain much benefit from doing some initial reading on op amp basic theory. There seems to be much available on the web.
 Check out Tangent's articles, and I think there were some good ones on Headwize for beginners, specifically for audio. Bear in mind that op amps are a basic building block used for many purposes other than audio - so not all are suited to this purpose.
 There are some good candidates listed earlier in this thread.


----------



## ROBSCIX

@Spudharris, Here is a pic I took last night of a couple new modules I built awhile ago.




 I have a habit of watermarking my shots after I take them, as I find pictures tend to find new homes quite quickly and they were taken for that forum orginally.
 Used Cardas Quad solder on these modules... The Dual LME49710 is one of my favorites. I am going to be building some more Dual To-99 modules very 
 soon using some other modules. It is almost build time again... Figured you might like the TO-99 pic as you said you have a "thing" for metal can opamps. 
 I like them also based on all the models I have.


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I'm new at this so should I be looking for just voltage feedback opamps? What about fet input opamps? I have grabbed a bunch of freebie current feedback opamps cause I was getting a little greedy last night at TI and LT's expense. I've grabbed about every one of the opamps mentioned so far made by Ti and LT. Any advice is greatly appreciated.

 thanks, joel 
	

	
	
		
		

		
			



_

 

very large topic as Murray mentioned. Some types are prefered for certain jobs such as many prefer Fet input for I/V. Generally in the designs talked about here everybody is using circuit where VFA (Voltage Feedback Amps)
 are being used for various tasks such as Curernt to votlage conversions of final buffering..etc.
 CFA's (Current Feedback Amp) also have their place but you usually cannot use one to replace another.
 Depending on your circuit you will need:
 DIP 8, Dual Inline Packaege with 8 pins. These are the type used with sockets in circuit where the opamps are replacable.
 SOIC, Small outline IC, is much smaller and surface mounted. You can get adapters to use these SOIC with a DIP8 socket.

 There are other types of "footprints" but these are usually the most common that people work with around here.
 Also make sure depending on your application and circuit you get the proper number of channels. Replacing a dual opamps with a single channel will blow the opamps and possibly damage the circuit. 
 There have been many great opamps recommending in this thread but some can be unstable in some circuits. 
 If your unsure about something just ask in this thread. Many here have been working with electronics and opamps for many years and others are just getting started


----------



## SpudHarris

That double module is great, not seen that before. I have separate L/R sockets so I only build singles on the Brown Dog Adapters like that one on the left.

 I have 2 AD8599's on the way $4 each!! They cost nearly £9 from Farnel UK so I got 2 including carriage for £6.83, can you believe that......

 ROBSCIX - YGPM


----------



## ROBSCIX

I figured you might like that dual 710HA's. 
 Great deal for the AD's. I find myself building and working more and more with TO-99 and discretes.
 Thx for the info in the PM. 
 I find I am doing more builds latley for myslef and associates, when build day comes around I usually have a list of units to build.
 What is your plan for the AD8599's?


----------



## SpudHarris

Well I'll build them both and keep one in my spares box, the other I'll have a play with in my P3+...

 I'll drop the 49710's out tonight and have a listen to the ADA4898-1's, I'll post my impressions later or tomorrow.

 What other TO-99's would you consider must haves? I love the 49710's and think they would take some beating, so something not so much better but different?

 Cheers


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well I'll build them both and keep one in my spares box, the other I'll have a play with in my P3+...

 I'll drop the 49710's out tonight and have a listen to the ADA4898-1's, I'll post my impressions later or tomorrow.

 What other TO-99's would you consider must haves? I love the 49710's and think they would take some beating, so something not so much better but different?

 Cheers_

 

For TO-99 must haves, I have a bit of a list but I will wait until I test them myself before giving recommendations.
 I agree with you about the 710HA's but I need them in a dual format for my circuit. The 720HA's aren't bad and I have been working with these since they were release but I seem to reach for the Dual 710 module more then the 720 modules.

 I want to do more testing with my AD modules....never enough time.


----------



## Reima

@ ROBSCIX where did you get the dual TO-99 adapter?
 RC


----------



## ROBSCIX

A freind of mine sent me a few from ASIA. I am considering just designing and having some made for personal use and for associates


----------



## Reima

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_A freind of mine sent me a few from ASIA. I am considering just designing and having some made for personal use and for associates_

 

Thanks, I have found a source in Asia as well, was hoping you had a source closer to home.
 RC


----------



## ROBSCIX

No way. they are hard to find in North America as I said I had to source them from ASIA through a associate.
 I was just going to give up and make my own this way I could control the quality and design aspects. I still may have some manufactured custom based on my designs who knows.


----------



## Reima

My source has quoted a price of $5.00 each, the price will be lower if I order more than 10.
 RC


----------



## ROBSCIX

That is not too bad if you have a use for them.
 Good luck with your build.


----------



## leeperry

anyone tried the OPA2107AP?

 it's pricey and I like the specs, plus my soundcard will be back from RMA early next week...need some toys! 
	

	
	
		
		

		
		
	


	




*PS:* apparently it's not too bad: http://209.85.229.132/search?q=cache...&hl=en&ct=clnk


----------



## gurubhai

I have tried OPA 2107AP.
 They have a nice warm sound, one of the better opamps that i have tried.

 Though I like the Linear ones (1358,1057) better.


----------



## 12Bass

I found the OPA2107 somewhat expensive and underwhelming, and not as good as the OPA827/OPA211/OPA2211A.


----------



## SpudHarris

I liked it but I agree it doesn't compare to the OPA211/2211, can't comment on the 827 cuz my samples are backordered......


----------



## morfic

The thread has grown fast, so i'm not going to check every post, searching the thread for "DC offset" has yielded no results mentioning Input Bias Current.

 I had a LT1364 that came with my Little Dot I+, naturally i wanted to try it in my cmoy, which taught me a valuable lesson, if you do not know what kind of voltage the "Input Bias Current" forced over your input resistor is, stick to FET opamps with IBC in the pA range and their resulting minuscule DC offsets or bipolars like the LM4562/LME49720 that are still in the nA range.
 If you just plug and play a bipolar opamp with an Input Bias Current in the uA range, you easily create a DC offset of headphone cooking proportions.
 Take the I+ hybrid amp for example, while with the LME49720 installed i measure <1mV DC offset, while the LT1364 rakes in 28mV of DC Offset (an i am adhering to Tangent's threshold of 20mV being safe limit).
 While the same two opamp cause ~10mV and ~300mV DC offset respectively (In my stock built cmoy). By changing the gain resistors and input resistor in the cmoy i was able to drop the LT1364 from 300mV to 100mV, it's still too high for comfort. I will buy the required resistors to control the DC Offset of the LT1364 later, the LME49720 is the best opamp a little money can buy anyway, the controlling of the LT1364's DC offset is entirely educational.

 Just thought i share that, in case people peruse the thread as a reference to just plug'n'play opamps in their commercial amps of which they know very little and take a chance with their headphones...

 To summarize it, stick to opamps with FET input transistors or the LME49720/LM4562 if you want a bipolar and want to know your headphones are safe.


----------



## diditmyself

Two ways to deal with input bias currents:

 I find the second messy with added caps and low input impedance. I use the first method in a discrete amp with good result.


----------



## Pluto2

Guys, next-gen audio opamp chips from TI!!!! Just came out last week : )
 OPA1611 (single) and OPA1612 (dual)


----------



## leeperry

lol, their distortion is even lower than the LME49722 
	

	
	
		
		

		
		
	


	




 no free samples, though..and when I click "purchase samples" nothing happens?! looks like it's not available yet 
	

	
	
		
		

		
		
	


	




*PS:* I've called LT to ask them if I would ever get my LT1057, and the guy told me that it's taking forever because these DIP8 chips are pretty rare these days....I really wanna try these ^^


----------



## ROBSCIX

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Guys, next-gen audio opamp chips from TI!!!! Just came out last week : )
 OPA1611 (single) and OPA1612 (dual)_

 

Thanx for the heads up. Will have to buy a few and try them out. 
 If you try them post your results.


----------



## leeperry

when you see the distortion rate, it's pretty clear that they market it to p*ss National off 
	

	
	
		
		

		
		
	


	




 competition is a good thing! I demand a LME49724 
	

	
	
		
		

		
		
	


	




 I've asked the LT guy I had on the phone why they don't play that distortion rate game, and he told me that they "don't have to"


----------



## majkel

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Guys, next-gen audio opamp chips from TI!!!! Just came out last week : )
 OPA1611 (single) and OPA1612 (dual)_

 

Looking at the specs it looks like a low cost version of the OPA211 - most of them is the same.


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Looking at the specs it looks like a low cost version of the OPA211 - most of them is the same._

 

I figured the same thing when I reviewed the spec sheet. 
 The noise value of 1.1 tipped me off as that is what caught my eye about the 211.
 According to the spec sheets, the 161X is marketed as a audio opamp instead of a precision opamp like the 211. Would be interesting to compare the two within the same circuit. I have a set of 211's I will have to buy some 1611 and 1612s for testing.


----------



## crapback

My initial impressions of the 2211's in my zero are a lack of low end detail and impact and a weird mid bass emphasis. I spent all that time soldering my first 2 SOIC's and they now get to sit, figures. I read in another thread that I shouldn't use .050 solder for soic's but my .025 hasn't arrived and I had to give it a shot. It wasn't that bad with a little help from an xacto helping hand. I wish i had some desolder braid instead of just a solder sucker. There's a video on youtube http://www.youtube.com/watch?v=HgoZCffFanEof a guy soldering a soic max232 with braid and he does it in seconds. Have any of you guys tried that before? 

 Oh well, back to the 4562's for now and more waiting for the other samples to arrive.


----------



## ROBSCIX

Just takes practice. The more your practice the better you get at the technique. Soldering braid is best used for de soldering but some get it into their technique for fixing bridges etc... Just like everything else, everybody has their own little quirks and tricks with soldering or desoldering..


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_*PS:* I've called LT to ask them if I would ever get my LT1057, and the guy told me that it's taking forever because these DIP8 chips are pretty rare these days....I really wanna try these ^^_

 

I just desoldered the OPA2604 line output on my Style Audio Peridot and soldered a spanking new IC socket so I can roll opamps. I was going thru my old stash of opamps from a few years ago and found me a nice shiny new LT1057. I originally had an LME49860 in there but the LT1057 sounds better to my ears...more impact and the mid-range is brought forward on my D2000s a bit which is very nice.


----------



## ROBSCIX

I find the LT1057 to sound "warm" offering more midbass and mid range without being too shrill or harsh. I hate trying to describe audio!

 The LME49860 and other that are similar in that series can have a harder "digital" type sound depending on the circuit and your gear/ears.
 I personally like the LM/LME series but I know many that do not...


----------



## SpudHarris

Well I have had the same chipset in my P3+ for about 4-5 days which has never been known. I have found a combo that makes my P3+ sound like an amp costing much, much more the SQ is astounding and I can't wait to try the JH13's (when they get here - bloody usless UPS)

 Anyhow, for anyone owning a P3+ you got to try this combo, I kid you not it is amazing in every respect. LME49710's (TO-99) in L/R - Hi-C Buf634's - LME49710's in G/V.


----------



## ROBSCIX

Yes, I have been having great results with the LME49710HA's. I am using them in a dual configuration w/ adapter as the pic I posted. 
 Different applications but great sound none the less.


----------



## SpudHarris

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_mmmmmmmm...... and now it is *sad tonal colour*? Did anyone go and get the LME49860? You will have to send it back as Andrea has changed his mind 
	

	
	
		
		

		
		
	


	


_

 

Yeah give him an hour or so & he'll be back to the good old LME49860


----------



## acvtre

Spud you have a pm.


----------



## SpudHarris

If it's dull and dead why don't you stop posting ? You don't give anything to it anyhow as you change your mind almost hourly as to what is 'The' best Opamp.

 No offence like......


----------



## 12Bass

LME49860, LME49722 are on their way.... and I still haven't auditioned AD797 and ADA4898-1. Have to get on that soon! LME49720HA was too pricey to consider ordering right now.


----------



## leeperry

I think $17 shipped for 3x49720HA is well worth the admittance price. I was completelly stunned by these, I will try them again on my STX tomorrow.

 I was initially blinded by the insanely whining trebles of the 49720NA, but that's *NOT* how music is supposed to sound like IMO. I also tried the LT1358 w/ fresh ears and the trebles indeed sound "digital" to death 
	

	
	
		
		

		
			





 as David Griesinger puts it on his website, headphones are very bright to increase clarity, and mixing on them is pointless for this very reason...so an unEQ'ed phone + some uber-bright op-amp is up to no good IMO. the 49720HA is pretty dark, yet sounds damn good on the STX...I didn't like it on the ST.

*PS:* I've received LT1361CN8 and LT1213ACN8 today.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_LME49860, LME49722 are on their way.... and I still haven't auditioned AD797 and ADA4898-1. Have to get on that soon! LME49720HA was too pricey to consider ordering right now._

 

Many suggest the LME49860 sounds similar to the LM4562NA and LME49720NA. 
 I have never did the comprison though. The LME49720HA's are not too bad but they are not the end of the road by any means.

 There are quite a few around here that speak highly of the AD797's -in one from or another. Personally AD opamps are some of my favorites in my collection. Just got done soldering up some new AD 8620's. Will be teseting these here in a bit!
 I have yet to test the ADA4898-1 but I have it on my list for future testing.


----------



## 12Bass

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I think $17 shipped for 3x49720HA is well worth the admittance price. I was completelly stunned by these, I will try them again on my STX tomorrow._

 

Digi-Key wants $20 CDN each. Too rich for my blood, especially considering that I've found the OPA2211A superior overall compared with the LME49720NA. Don't expect a lot of difference between LM4562/LME49720/LME49860.... but thought I'd give them a listen regardless. LME49722 might be different....


----------



## leeperry

well, if your ethics are too high to ask National for samples..I guess these TO99 parts are pretty damn pricey in retail shops indeed 
	

	
	
		
		

		
		
	


	




 49720NA and HA are night and day, literally! it's been thoroughly discussed in this thread: http://www.diyaudio.com/forums/showt...1&pagenumber=4


----------



## Mannevond

Very interesting tread. First of all, I'm no expert in the field of electronics or high-end audio, but I know "good sound" when I hear it.

 A few weeks ago I built my first CMoy. It is built with TLE2426 railsplitter, 470uF power caps, 0.22uF decoupling caps and 18V battery power (original kit had 9V supply), so lack of voltage/power shouldn't be an issue here.

 I have used JRC4560, OPA2134, AD823 and AD8620 in the amp. I won't even comment on the JRC chip as I hated it from the first minute. Don't ask 
	

	
	
		
		

		
		
	


	




 No doubt, the AD8620 is the best of the lot for me with my Beyerdynamic DT770 32Ohms. It gives the widest soundstage and best details from the deepest bass to the brightest trebles.
 The 823 is pretty nice on low volumes, but trebles become quite harsh when the volume gets high.
 The 2134 is ok, but not by any means spectacular, neither with 9V or 18V power supply.

 I also tested it as a preamp directly into my livingroom amp's power stage. The 2134 was not to my liking, but I have a harder time deciding between the 823 and the 8620 than I have with the headphones. This may be because of the fact that the weaker output of the 823 isn't as limiting in a preamp as it is with headphones 
	

	
	
		
		

		
		
	


	




 All in all, I think the 8620 is going to stay in my CMoy in the foreseeable future. When someone suggest something "even" better for my headphones, I might change my mind. Should I put my flameproof suit on now? 
	

	
	
		
		

		
		
	


	




 Edit: typo


----------



## crapback

I just got a chance to stop home and grab a bunch of opamps to try out in my zero. I've got the 627's in the dac so I've just been trying out different ones in the amp. So far I've tried the lt1364, lt1355, lt1208, opa2604, opa2107, opa2132 and lm49720. I need to give each one more time of course but based on the initial impressions of each set I'm partial to the lt1208's. The bass has depth and some serious impact. The mids are pretty smooth and the highs are nice and bright. It seems like a very well rounded overall sound up to this point. The soundstage is very wide and almost, but not quite forward, if that makes sense to anyone else. The imaging and detail has actually fooled me on a few songs and had me looking around for something I was hearing in the music.
 I didn't think I could get this much of an improvement over the 4562's that were in it but I like this kind of surprise. It's kind of nice to hear my 650's sparkle too. I'll have to see what some burn in time does to my new little buddies.


----------



## acvtre

What are the main defferencies between the opa627 and opa637?
 Which one would you suggest?


----------



## leeperry

BTW, the OPA1612AID are available as samples now...don't ask me how I know


----------



## murrays

Quote:


  Originally Posted by *acvtre* /img/forum/go_quote.gif 
_What are the main defferencies between the opa627 and opa637?
 Which one would you suggest?_

 

The OPA627 is internally compensated to be unity gain stable, the OPA637 is not. Therefore the OPA637 may not be stable in some circuits. I have found that marginal stability and ringing may sometimes be interpreted as adding sound "character" or edginess.


----------



## acvtre

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_The OPA627 is internally compensated to be unity gain stable, the OPA637 is not. Therefore the OPA637 may not be stable in some circuits. I have found that marginal stability and ringing may sometimes be interpreted as adding sound "character" or edginess._

 

So it's better the opa637? What does it actually mean gain stable? In waht cases won't be stable the 637?


----------



## murrays

Quote:


  Originally Posted by *acvtre* /img/forum/go_quote.gif 
_So it's better the opa637? What does it actually mean gain stable? In waht cases won't be stable the 637?_

 

The datasheet specifies that OPA637 is stable at gains >= 5. It also reminds you to take noise gain into consideration. If a particular op amp is not suited to a particular circuit it may be come unstable. The worst type of instability will result in continuous high-frequency oscillations, overheating and distortion. If you can't check for instability (e.g. with an oscilloscope) you should rely on advice from others who have experience of substituting chips in the particular circuit.


----------



## acvtre

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_The datasheet specifies that OPA637 is stable at gains >= 5. It also reminds you to take noise gain into consideration. If a particular op amp is not suited to a particular circuit it may be come unstable. The worst type of instability will result in continuous high-frequency oscillations, overheating and distortion. If you can't check for instability (e.g. with an oscilloscope) you should rely on advice from others who have experience of substituting chips in the particular circuit._

 

What would you suggest for my ibasso p3+?


----------



## ROBSCIX

It is not to say that the OPA637 won't be stable in your circuit. You need to check and verify the circuit meets the criteria mentioned in the spec sheet. They are great sounding opamps as I have two models but they are a bit "touchy" depending on the circuit. Unles you know for sure your circuit can handle the 637's I suggest the 627 instead as it is not as fast..IIRC and has internal compensation.


----------



## morfic

Quote:


  Originally Posted by *cry* /img/forum/go_quote.gif 
_Well, yes... the LME49710NA being better than the LME49710HA, more coherent and more colorful... I tried both of them in the DIYEDEN SVDAC05. I reaaaallly wanted to like the LME49710HA, but... that I ended up removing sockets and soldering in the LME49710NA should tell you something 
	

	
	
		
		

		
			






 But... now I like the other DAC with those two LT1677IS8 better. 
	

	
	
		
		

		
		
	


	


_

 

You liked the DIP8 better than than the TO99?


----------



## leeperry

hehe Andrea, if the 49710HA is like the 49720HA w/ slightly better crosstalk specs...then I think we got a winner indeed 
	

	
	
		
		

		
		
	


	




 the 49720HA on the STX simply sounds exactly like what I'm looking for. good low end bass response, wide SS, very soft trebles and clear mids.

 I'm gonna take it easy on the op-amps rolling for a little while, these sound just super neato


----------



## ROBSCIX

Quote:


  Originally Posted by *morfic* /img/forum/go_quote.gif 
_You liked the DIP8 better than than the TO99?_

 

Speaking of TO-99 LME's. Here are a new set I built for an associate.
 We have a dual LME49710HA and three LME49720HA's.


----------



## morfic

How much do the adapted LME49720 run? How much for a single adapted LME49710?


----------



## ROBSCIX

Not sure never did the math. I have some other units on the drawing board also, that should be very nice for sound quality but I don't want to mention the actual units before I do some testing.


----------



## Pluto2

Heard through the grapevine that these opa1611/12 are much superb than opa211/2211...samples are to be delivered sometime in September : )


----------



## leeperry

the low end bass response is as good as the 49720HA? I'm starting to think that indeed the metal cap kills a lot of interferences! I've never heard such good bass response from a plastic chip 
	

	
	
		
		

		
		
	


	




 and the trebles are so soft, not agressive or whining like the 49720NA..or the LT1358.

 trebles are not supposed to make blood leak out of your ears in the first place! you have to counter-balance the brightness of most headphones...and God does National know a thing or two about soundstage 
	

	
	
		
		

		
		
	


	




 it's the same exact design as the 49720NA, the only difference is the metal cap..even an ex-National engineer said that they measure identically...and that he couldn't explain the SQ improvement


----------



## majkel

Have you tried the LT1115? This one is recommended by LT for audio circuits, so I ordered the samples. I also ordered the LT1677CN8. After many action turnovers I still find the OPA228 to be one step further than the rest, so close to the music and with touchable microdetails... 
	

	
	
		
		

		
		
	


	




 The OPA211 is too focused and the microdetails lose freedom while the LT1028ACN8 sounds overly articulated remaining tonally neutral.


----------



## leeperry

well, maybe "soft" was not the right word...I'd call the 49720HA bass response very clear, as low end as can be and just "flowing", very natural.

 on the STX, it's a riot! 
	

	
	
		
		

		
		
	


	




 I'm still dubious that a plastic chip could match it


----------



## majkel

Quote:


  Originally Posted by *bunchofsheeps* /img/forum/go_quote.gif 
_My only incertitude about the OPA228 is on the tonality... it probably is surpassed by the LT1028 at that, at least with the CS4398. Just "speculating"..._

 

I set the tonality of my DAC mainly by capacitors in analog and digital supply sections. Also, the P series is brighter and less colored than the PA series which applies to both OPA228 and OPA2228. Two single chips provide audibly better channel separation with more precise imaging. The other qualities remain very similar.


----------



## morfic

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Have you tried the LT1115? This one is recommended by LT for audio circuits, so I ordered the samples. I also ordered the LT1677CN8. After many action turnovers I still find the OPA228 to be one step further than the rest, so close to the music and with touchable microdetails... 
	

	
	
		
		

		
		
	


	




 The OPA211 is too focused and the microdetails lose freedom while the LT1028ACN8 sounds overly articulated remaining tonally neutral._

 

I hope your circuit is built for the LT1115, if not, you won't get to hear much nice things. It's not a plug&play chip for your avg amp.


----------



## ROBSCIX

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Heard through the grapevine that these opa1611/12 are much superb than opa211/2211...samples are to be delivered sometime in September : )_

 

I have reviewed the spec sheets and I am very interested in testing this unit out in both models.


----------



## leeperry

Quote:


  Originally Posted by *rescue* /img/forum/go_quote.gif 
_Between yesterday and this morning I made a group test 
	

	
	
		
		

		
		
	


	




 that made it apparent that the LT1677 is the best sounding opamp I have, in my setup...

 OPA211: nice but too "washy" tonally

 LT1028: nice but too dry

 LME49720HA: quite nice really, only lacks that last touch of magic (another word for naturalness)

 EL2228: this didn't even work

 LT1677: magical..._

 

yep, atm I'm using 3x 49720HA, 2 for I/V and 1 for buffer..and I 
	

	
	
		
		

		
		
	


	




 it.

 LT1677 is single apparently...and the bass is as nice as the 49720HA?

 I use Mazzy Star recordings these days to benchmark these parts, and Hope Sandoval's voice just sounds as grasping as can be 
	

	
	
		
		

		
		
	


	




 so how good is the 49722MA then? flabby bass like the 720NA?


----------



## acvtre

Quote:


  Originally Posted by *rescue* /img/forum/go_quote.gif 
_Between yesterday and this morning I made a group test 
	

	
	
		
		

		
		
	


	




 that made it apparent that the LT1677 is the best sounding opamp I have, in my setup...


 OPA211: nice but too "washy" tonally

 LT1028: nice but too dry

 LME49720HA: quite nice really, only lacks that last touch of magic (another word for naturalness)

 EL2228: this didn't even work

 LT1677: magical..._

 

Where can I find an opamp like the LT1677? noone sells it on ebay. I mean, is there a trustworthy seller or do I have to buy each kind in a different shop?


----------



## ROBSCIX

Quote:


  Originally Posted by *acvtre* /img/forum/go_quote.gif 
_Where can I find an opamp like the LT1677? noone sells it on ebay. I mean, is there a trustworthy seller or do I have to buy each kind in a different shop?_

 

Try distributors. Can you not order this part from the manufacturer?


----------



## acvtre

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Try distributors. Can you not order this part from the manufacturer?_

 

I don't know the distributors.


----------



## ecclesand

Quote:


  Originally Posted by *acvtre* /img/forum/go_quote.gif 
_I don't know the distributors._

 

National Semiconductor (LME opamps)
 Analog Devices (AD opamps)
 Texas Instruments (OPA opamps)
 Linear Technology (LT opamps)

 You can also buy them from Digi-Key. I have always been able to find every opamp I was looking for at Digi-Key.


----------



## acvtre

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_National Semiconductor (LME opamps)
 Analog Devices (AD opamps)
 Texas Instruments (OPA opamps)
 Linear Technology (LT opamps)

 You can also buy them from Digi-Key. I have always been able to find every opamp I was looking for at Digi-Key._

 

Yah I know it but the shipping cost is enormous: 18€ for me. Really too much.


----------



## ROBSCIX

Can you not find a local dealer? Many of these companies should have brances in your area.

 Do you not have any electronics distributors in your area?


----------



## acvtre

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Can you not find a local dealer? Many of these companies should have brances in your area.

 Do you not have any electronics distributors in your area?_

 

No, I don't and I live in Italy so it's pretty impossible to find something.


----------



## leeperry

just ask for free samples, and yes digikey shipping costs are crazy..


----------



## ecclesand

I received the LME49720NA yesterday and tried it out. At first, the treble sounded pretty harsh, but then mellowed out after a couple hours. The bass is OK...a bit bloated. To me this opamp sounds a bit dark. Compared to the LT1057, it lacks detail in all frequencies. I also thought the soundstage on the LT1057, though not as wide as the LME49720NA, was more believable. I have some the LME49720HAs on order as well as some of the TO-99 to DIP8 browndog adapters. I also have more LT samples on the way. For me and now, the LT1057 is still the one to beat.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I received the LME49720NA yesterday and tried it out. At first, the treble sounded pretty harsh, but then mellowed out after a couple hours. The bass is OK...a bit bloated. To me this opamp sounds a bit dark. Compared to the LT1057, it lacks detail in all frequencies. I also thought the soundstage on the LT1057, though not as wide as the LME49720NA, was more believable. I have some the LME49720HAs on order as well as some of the TO-99 to DIP8 browndog adapters. I also have more LT samples on the way. For me and now, the LT1057 is still the one to beat._

 

There are quite a few around here that like the sound of the LT1057. I like them also and I am interested in building some TO-99 version with adapters.


----------



## leeperry

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I have some the LME49720HAs on order as well as some of the TO-99 to DIP8 browndog adapters._

 

adapters are really not required, they will only increase distorsion due to poor PCB quality and so.

 audioman54(ex national engineer) on diyaudio.com bends them to fit DIP8, I guess he knows what he's up to 
	

	
	
		
		

		
		
	


	




 he said he's also able to bend DIP8 to TO99, but it'd be far more complicated 
	

	
	
		
		

		
		
	


	




 on my STX: 
http://www.head-fi.org/forums/5739469-post137.html
http://www.head-fi.org/forums/5739776-post143.html

 fzman also bends them, and so far so good for both of us...these sound absolutely amazing. I don't see any plastic chip outshining them tbh.

 they're like the DT770/600Ω, a manufacturer's secret weapon for sure


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_adapters are really not required, they will only increase distorsion due to poor PCB quality and so.

 audioman54(ex national engineer) on diyaudio.com bends them to fit DIP8, I guess he knows what he's up to 
	

	
	
		
		

		
		
	


	




 he said he's also able to bend DIP8 to TO99, but it'd be far more complicated 
	

	
	
		
		

		
		
	


	




 on my STX: 
http://www.head-fi.org/forums/5739469-post137.html
http://www.head-fi.org/forums/5739776-post143.html

 fzman also bends them, and so far so good for both of us...these sound absolutely amazing. I don't see any plastic chip outshining them tbh.

 they're like the DT770/600Ω, a manufacturer's secret weapon for sure 
	

	
	
		
		

		
		
	


	


_

 

I have a couple coming so I'll try one with the adapter and one without.

 I've been listening to the LT1358...both CN8 and IN8...and they're just OK. Nothing really wows me with these. Bass feels a bit light with less impact than the LT1057. Detail is OK, soundstage is OK, mids are a tiny bit recessed and the highs seem a bit rolled off...little to no sparkle. They just seem boring. I'm going to give them another day...maybe they'll blossom.

 This is as much fun as rolling tubes!


----------



## murrays

Quote:


  Originally Posted by *acvtre* /img/forum/go_quote.gif 
_No, I don't and I live in Italy so it's pretty impossible to find something.
	

	
	
		
		

		
		
	


	


_

 

Try checking out the Italian websites for Farnell (it.farnell.com) and RS (it.rs-online.com/web/). They are trade suppliers and can be fairly expensive (at least in NZ) but they have a wide range of components and are professional and quick to deliver.


----------



## Cynips

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I just desoldered the OPA2604 line output on my Style Audio Peridot and soldered a spanking new IC socket so I can roll opamps. I was going thru my old stash of opamps from a few years ago and found me a nice shiny new LT1057. I originally had an LME49860 in there but the LT1057 sounds better to my ears...more impact and the mid-range is brought forward on my D2000s a bit which is very nice._

 

Had a few hours with the LME49860NA right before going on vacation. Although I need to listen more and should also switch back to others I basically agree with your comparison with the LT1057. I find the 49860 somewhat cold because of slightly overdone highs. But don't get me wrong, it's still a relatively good and balanced chip.


----------



## leeperry

ok ok, I might order a bunch of 1677 then! I got plenty browndogs, I'm just bored of rolling op-amps to get whining trebles and flabby bass 
	

	
	
		
		

		
		
	


	




 well, the 49720HA are firmly installed on my STX and my PC never moves...also, I don't shake the case on purpose so I think I'm pretty safe w/ the bending 
	

	
	
		
		

		
		
	


	




 Yeah, I've bought some 49722MA but I don't think I'd like them...I prolly won't get them installed on browndog's.

 I'll wait for the new TI chip to ship, and I'll ask my friend to solder them(together w/ the LT1677). I wanted to wait for the LT1028, but LT doesn't seem willing to send them to me...their loss I guess, or not 
	

	
	
		
		

		
		
	


	




*PS:* OK, ordered two 1678 for I/V and two 1677 for buffer


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_There are quite a few around here that like the sound of the LT1057. I like them also and I am interested in building some TO-99 version with adapters._

 

I looked, but cannot find the LT1057 in the TO-99 version. Can you tell me where you got (or will be getting) them from? I do understand your interest...if the metal cap improves the LME49720NA, then theoretically, it should improve the LT1057ACN8.

 EDIT: After several more hours, the LT1358CN8 has greatly improved. The treble is more extended, sparkly, and snappy. The bottom end is fuller and the detail is very good. Bass impact is right on. These are very close to the LT1057 to my ears, just not quite there. I think I have an affinity with the Linear Technology opamps.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I looked, but cannot find the LT1057 in the TO-99 version. Can you tell me where you got (or will be getting) them from? I do understand your interest...if the metal cap improves the LME49720NA, then theoretically, it should improve the LT1057ACN8.

 EDIT: After several more hours, the LT1358CN8 has greatly improved. The treble is more extended, sparkly, and snappy. The bottom end is fuller and the detail is very good. Bass impact is right on. These are very close to the LT1057 to my ears, just not quite there. I think I have an affinity with the Linear Technology opamps._

 

I have many contacts overseas and they seem to have components that aren't readily available here. I may get in a bunch of them as some associates showed interest also. I have a list of new units I want to order in.


----------



## ROBSCIX

Here are some new units I built for a associate:


----------



## ecclesand

Quote:


  Originally Posted by *acrobata* /img/forum/go_quote.gif 
_I like that you like those opamps. I find the LT1358 an excellent dual. What supply voltage do you use them at?_

 

Dammit Andrea!

 I'm using them with a PCM1793 DAC and according to the spec sheet for this DAC, the analog output voltage is 2.1V. Of course, that's if I'm reading the spec sheet correctly.


----------



## ROBSCIX

Just ignore the trolls.


----------



## Robin W.

After being a little skeptical of the difference between the plastic/metal can version of the LME49720 I finally tried it.... I was wrong, wow what a difference 
	

	
	
		
		

		
		
	


	



 I'm using a plastic LME49710 in the ground channel (710HA on order) but the L/R are parallel LME49720HA's (one metal can per channel) and the difference is quite wonderful. My default configuration is LME49860's L/R and LM6171 for ground, which sounds great with every 'phone I've ever tried on it. But this new combo adds alot of detail and depth to most recordings (side note, the sound was "off" using the LM6171 or OPA627 in the ground channel) but came around nicely when I put in an LME49710. I was considering offering the AD8620/AD8610 as an upgrade pack, but these metal cans are much closer to the sound I was after with this amp. Also the AD8620/10 was either magical or CRAP with the Grado HF-2's there was no inbetween. So not really listenable for a wide variety of music. I can't believe I've had these HA's in my junk box for a year or so because I miss ordered.


----------



## ROBSCIX

Quote:


  Originally Posted by *rwaudio* /img/forum/go_quote.gif 
_After being a little skeptical of the difference between the plastic/metal can version of the LME49720 I finally tried it.... I was wrong, wow what a difference 
	

	
	
		
		

		
		
	


	



 I'm using a plastic LME49710 in the ground channel (710HA on order) but the L/R are parallel LME49720HA's (one metal can per channel) and the difference is quite wonderful. My default configuration is LME49860's L/R and LM6171 for ground, which sounds great with every 'phone I've ever tried on it. But this new combo adds alot of detail and depth to most recordings (side note, the sound was "off" using the LM6171 or OPA627 in the ground channel) but came around nicely when I put in an LME49710. I was considering offering the AD8620/AD8610 as an upgrade pack, but these metal cans are much closer to the sound I was after with this amp. Also the AD8620/10 was either magical or CRAP with the Grado HF-2's there was no inbetween. So not really listenable for a wide variety of music. I can't believe I've had these HA's in my junk box for a year or so because I miss ordered._

 

They are decent sound units for sure. Metal can TO-99 modules seem to be prefered by many for audio circuits. I have quite a few different TO-99 versions and I am considering building more. 
 Enjoy.


----------



## leeperry

Quote:


  Originally Posted by *trollerie* /img/forum/go_quote.gif 
_Hmm, the LME49720HA, I find, adds an electric touch to transients that I don't quite like._

 

as I/V, buffer, or both?

 yep, it's not perfect...but none of these chips is ...the op-amp chip design is flawed from the ground up I think. Most DIY ppl try to avoid using them altogether apparently.

 I like the soundstage and the low end bass on that chip, they're simply spot-on 
	

	
	
		
		

		
		
	


	




 but yeah, the mids seem to have something not really perfect going on, can't really put my finger on it...tell you what, I got a bunch of OPA211/2211 and browndogs, I'll bug a friend to solder them for me 
	

	
	
		
		

		
		
	


	




 if LT ever accepts to send me the 1677/1678 I'll have them in +4 weeks, God knows what will have happened in the meantime....maybe I'll have gotten bored of rolling and ordered some Audio-Gd Moon's by then 
	

	
	
		
		

		
		
	


	




 Should I even try the 2132P? or the 2107AP?


----------



## ecclesand

Quote:


  Originally Posted by *trollerie* /img/forum/go_quote.gif 
_





 I said the opamp's supply voltage, not the DAC's nominal output voltage._

 

Andrea..I know little to nothing about this stuff, but I'm trying to learn. The opamps in my DAC are the output stage for the DAC chip, no? The actual power to the DAC is 5V via USB.


----------



## Robin W.

I think the type of circuit (or amp/soundcard) and headphones in use would be a valueable addition to some opinions in this thread.
 There's a lot more to how an amp sounds then just the op-amp it uses. 
 The headphones used will give readers a better idea of the subjective traits.
 It's two totally different things saying the highs became harsh depending if you have an HD650 or SR325.


----------



## leeperry

ahhhhhhh, you know it's getting obsessive when you decide to roll op-amps at 1AM 
	

	
	
		
		

		
		
	


	




 still undecided whether I'll try the 2132P or the 2107AP 
	

	
	
		
		

		
		
	


	




 yeah discrete has crazy distortion, and 5532 pretty low...figures don't mean jack -sometimes- -possibly- -maybe-


----------



## leeperry

hahaahaha: éŸ³éŸ¿ç™¼ç‡’ç¶² HiFi Fever :: è§€çœ‹æ–‡ç«* - opa 627bp in MHZS cd33

  Quote:


 By the way how much better the opa2107 compare to opa2132? 
 

 Quote:


 2107 has a very similar sonic signature to the OPA627 and also has the advantage of being a dual channel chip (dil8) It is slightly less chocolaty sounding than the 627 and I have loads of 2107 
 

"_chocolaty sounding_"
	

	
	
		
		

		
		
	


	




 that doesn't help -at all-, but this was priceless


----------



## Kuze

So this is OpAmp's are now and addiction, i feel like I'm becoming an addict myself.


----------



## joe_cool

Quote:


 "_chocolaty sounding_"
	

	
	
		
		

		
		
	


	




 that doesn't help -at all-, but this was priceless 
	

	
	
		
		

		
		
	


	



 

Maybe he's referring to the plastic-nasal sound of the 2132-2134. To me it sounds like a cheap clarinet.


----------



## Kuze

Operation Amplifiers (OPAMPs)

 Q: What does the letter at the end of OPAMP model mean such as OPA627AU, OPA627BU, OPA627BM, OPA627SM?
 A: The first letter, ‘A’,’B’,’S’ means ‘OPAMP Grade’ and the quality is better in following order.
 ‘A’ < ‘B’ < ‘S’
 The second letter, ‘U’,’M’,’P’ means ‘package type’.
 P: DIP type
 U: SMD(SOIC-8) type
 M: Metal Can type(It protects against the noise and electricity)
 Therefore the SM type is the highest price as the best sound quality.


----------



## cobaltmute

Pimeta V2 - so a dual opamp for LR and single for G followed by LMH6321 for all three channels.

 Tried 
 LME49720/LME49710
 LME49720/OPA602
 OPA2107/OPA602
 (all powered at 15v)

 For my liking, the LMEs were way to bright. After 1/2 hour of listening, I just wanted to turn the amp off. The OPA combo was much nicer to listen to.

 Differential to Single Ended conversion in my DAC.
 LME49721 - again overly bright in the high end, and slightly boomy bass.
 LMH6643 - I find this a much better sound, fine detail in the high end without being harsh and well controlled bass.
 (both were powered by +- 2.5v)


----------



## n_maher

Guys/gals, if you believe a poster is Andrea simply report it and it'll be taken care of.


----------



## majkel

Let me tell you I prefer the AD797BRZ to everything again. Classical tells me that - virtually no coloration, natural reverb, free, wide space. I fixed some bad mods, and added some good mods to the DAC PSU. The OPA228P is second but close, others don't catch up.


----------



## majkel

I haven't received my LT samples yest. There are some LT1677. The AD797BRZ are available in Farnell. I'm not sure they serve Italy. The OPA211 corrupts the sounds in a strange manner making the trebles thin and too focused. The LT1028 on the other hand lacks a bit of decay fluency and natural merging of the sound images in the soundstage They are kind of limited.


----------



## majkel

So it looks like I don't agree with the OPA211 interpretation. 
	

	
	
		
		

		
			





 It shapes the soundstage in the way I don't like and feel it's bent improperly. However it's still a very good op-amp. Sometimes I'm curious of OP27A/E but they are damn expensive. The AD743 aren't available as free samples, either.


----------



## majkel

Quote:


  Originally Posted by *reported* /img/forum/go_quote.gif 
_There's no doubting *anymore*_

 

Yeah, sure... undoubtedly! We'll be missing you.


----------



## leeperry

ok I'll try the 2107AP in a little while


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Let me tell you I prefer the AD797BRZ to everything again. Classical tells me that - virtually no coloration, natural reverb, free, wide space. I fixed some bad mods, and added some good mods to the DAC PSU. The OPA228P is second but close, others don't catch up._

 

You mentioned this in another thread. IIRC, you also said the different versions had different degress of sound quality.
 I have a AD797 module around but not sure which chip it is. I have been considering building some new AD797's for my collection. Do you have opinions on other AD models?
 There have been a few AD models that I have been testing for myself and others.


----------



## leeperry

well I forgot that I lended some 2107AP to a friend, so I'm using 3x 2132P atm...they seem to sound pretty good, indeed 
	

	
	
		
		

		
		
	


	




 I still think that the LM49720 specs don't match my soundcard design, their GBW is way too high at 55Mhz...the stock 2114 are 15MHz! the 2132P is 20.

 I wouldn't dare trying the THS4032 at 100Mhz on it, apparently most audio op-amps designs carry a 50MHz max GBW


----------



## leeperry

been listening to the 2132P for a little while now, I think I agree w/ this thread: http://www.head-fi.org/forums/f6/opa...-ad823-328029/

 now I understand what it means that an op-amp can sound "grainy", and I do agree that the 49720 can become very annoying due to TOO much details in the trebles.

 this 2132P feels like "comfort food" as said in that link above, it unveils a lot of details and doesn't try to impress you...it just flows, very "liquid" and yet still pretty forgiving 
	

	
	
		
		

		
		
	


	




 I've tried it on DNB, low end bass response is great and it's far from "slow": DJ Hype Presents Drum 'n' Bass Essentials: Amazon.co.uk

 if the 2107PA is even better, I can't wait! I also got the 2227P but apparently some ppl in that link say that it's worthless.


----------



## morfic

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_been listening to the 2132P for a little while now, I think I agree w/ this thread: http://www.head-fi.org/forums/f6/opa...-ad823-328029/

 now I understand what it means that an op-amp can sound "grainy", and I do agree that the 49720 can become very annoying due to TOO much details in the trebles.

 this 2132P feels like "comfort food" as said in that link above, it unveils a lot of details and doesn't try to impress you...it just flows, very "liquid" and yet still pretty forgiving 
	

	
	
		
		

		
		
	


	




 I've tried it on DNB, low end bass response is great and it's far from "slow": DJ Hype Presents Drum 'n' Bass Essentials: Amazon.co.uk

 if the 2107PA is even better, I can't wait! I also got the 2227P but apparently some ppl in that link say that it's worthless._

 

Do you listen with K701/K702?


----------



## leeperry

nope, full genuine leather Manufaktur DT770/600Ω on an Asus STX

 I just love their sound, and I've modded the hell of them(dampening, drivers angling)...on the STX they do wonders 
	

	
	
		
		

		
		
	


	




 humm, I very much enjoy these 2132P....the so-called "laid-back" BB sound I guess


----------



## cobaltmute

I've always liked a laid back sound. It needs to be detailed and clear, but not in your face.

 I thought the OPA2227 was pretty good when I first had it in my CMOY and my Pimeta1. I then got the OPA2107 in it and it was heads above to me. It was obvious from the get-go and only got better with more listening.

 I'd really to try the OPA2228, and the OPA637/627. If they carry on the Burr-Brown sound, they should be interesting.


----------



## murrays

Quote:


  Originally Posted by *club mad* /img/forum/go_quote.gif 
_1x LME49723 -- the others too bright? Try this that has lower 17 MHz bandwidth and 8 V/us slew rate. I was inspired by the very-well-reviewed Yamaha CD-S700 CD player..._

 

I hope you realise that is 17 MHz, not 17 kHz 
	

	
	
		
		

		
		
	


	




. It should still end up with a flat audio response in a properly designed circuit (unless you run a gain of over 500x).


----------



## leeperry

Quote:


  Originally Posted by *club mad* /img/forum/go_quote.gif 
_Ah see, I was not that wrong.

 The OPA2132P does have a fast and snappy bass BTW! One of the best bass responses I know of. And the expressive mids...

 I just made myself a few new "modules"...

 2x OPA132UA (improves on the OPA2132P) 
 [..]

 P.S. Don't expect too much from the OPA2107. Also it's fully biased internally only from 20V total (+/- 10V)._

 

indeed thanks for the tip! there's something in the mids of the 2132P that none of the chips I tried before ever offered me 
	

	
	
		
		

		
		
	


	




 more "substance", more "micro-details"?! its sound matches the description of "discrete" I usually read...the mids have sort of a "cinema grain" basically 
	

	
	
		
		

		
		
	


	




 actually, I think I have some OPA132U around...I'll have a look 
	

	
	
		
		

		
		
	


	




 but now I understand why some ppl said that the 49720 can be uneasy due to too much details, it's indeed a very fatiguing and unnatural op-amp...I wonder why the internet hype got so big on this one! even on french forums, ppl say that it's miles better than the OPA2132


----------



## ROBSCIX

Quote:


  Originally Posted by *cobaltmute* /img/forum/go_quote.gif 
_I've always liked a laid back sound. It needs to be detailed and clear, but not in your face.

 I thought the OPA2227 was pretty good when I first had it in my CMOY and my Pimeta1. I then got the OPA2107 in it and it was heads above to me. It was obvious from the get-go and only got better with more listening.

 I'd really to try the OPA2228, and the OPA637/627. If they carry on the Burr-Brown sound, they should be interesting._

 

Burr Browns are known for that laidback sound. The OPA2227 is a good amplifier and most like it for the bass response but say it lacks in other areas. I always keep a few around for certain applications.
 The OPA2107 is a great amplifier and highly recommended by many, I like this one also but it can be too clinical for some. 
 People have said the OPA2107 is the closest you get to the sound of the 627 without paying the price of the 627's. Considering the signature of both I would say this is a fairly accurate statement.
 Burr Brown has some great opamps for audio in my opinion and all seem to have that same type of laid back sound.


----------



## cobaltmute

As a Diff to SE converter in my DAC, the LMH6643 brings tons of detail. The laid back nature of the 2107 mellows that so it doesn't get fatiguing at all. That combo definitely could be seen as clinical, even a bit dry in some areas. 

 Using the LME49720 in place of the 2107 got ugly really fast.

 I really need to try out some of the AD parts that some people like. Got some AD744s that I want to try using the compensation pin...


----------



## ROBSCIX

Quote:


  Originally Posted by *cobaltmute* /img/forum/go_quote.gif 
_As a Diff to SE converter in my DAC, the LMH6643 brings tons of detail. The laid back nature of the 2107 mellows that so it doesn't get fatiguing at all. That combo definitely could be seen as clinical, even a bit dry in some areas. 

 Using the LME49720 in place of the 2107 got ugly really fast.

 I really need to try out some of the AD parts that some people like. Got some AD744s that I want to try using the compensation pin..._

 

I have never tried the LMH6643. I will have to review the specifications
 It depends on the circuit and task but I usually prefer the dual 710HA to the single 720HA. I have them both in adapters and they are some of my favorites AD parts are also very good for audio.


----------



## fzman

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_ but I usually prefer the dual 710HA to the single 720HA. I have them both in adapters and they are some of my favorites AD parts are also very good for audio._

 

lme's are national parts -- i know it was a slip of the tongue- so to speak


----------



## ROBSCIX

Quote:


  Originally Posted by *fzman* /img/forum/go_quote.gif 
_lme's are national parts -- i know it was a slip of the tongue- so to speak_

 

Yes I know they are National parts. 
 It wasn't a slip of the tongue. I forgot the punctuation -a period.
 I get typing fast and miss punctuaiton sometimes.
 The other poster mentioned the National parts and at the end mention he wanted to try some other AD parts. 

 I added the proper punctuaiton but never changed any wording, so here is how it should have been:
  Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I have never tried the LMH6643. I will have to review the specifications
 It depends on the circuit and task but I usually prefer the dual 710HA to the single 720HA. I have them both in adapters and they are some of my favorites*.* 
 AD parts are also very good for audio._


----------



## leeperry

I've stumbled upon this italian comparison between IC/discrete op-amps: Google Translate

 they tried them on the Prodigy HD2 Deluxe Edition(w/ improved caps, such as Sanyo OS), they didn't like the audio-GD Moon and say that the burson blows everything out.

 I'm not satisfied w/ my STX soundcard(fixed samplerate in the drivers, crappy HP amp, unstable system hogging CMI drivers), and I'm gonna shoot for this pimped HD2 I think 
	

	
	
		
		

		
			





 it's got many improved caps and op-amps(OPA2134/OPA2604) over the stock european/US version, and bit-matched drivers...for $130 shipped on ebay it's a steal. it's got machined DIP8 sockets too!

http://audiotrak.co.kr/images/advance_de_eng_04.jpg
http://audiotrak.co.kr/images/advance_de_eng_08.jpg
http://i406.photobucket.com/albums/p...y/DSCF2051.jpg

 and the AK4396 seems to work in such a way that you can bypass the buffer op-amp w/ 2 wires in the socket, sounds interesting


----------



## ecclesand

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_...I'm partial to the lt1208's. The bass has depth and some serious impact. The mids are pretty smooth and the highs are nice and bright. It seems like a very well rounded overall sound up to this point. The soundstage is very wide and almost, but not quite forward, if that makes sense to anyone else. The imaging and detail has actually fooled me on a few songs and had me looking around for something I was hearing in the music._

 

I'm listening to the LT1208CN8 now and I wholeheartedly agree. Very fun opamp!


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I'm listening to the LT1208CN8 now and I wholeheartedly agree. Very fun opamp!_

 

I am not sure if I have any of them. I will have to put them on the list of units to check out. Linear tech has some great opamps based on my testing and what I have read.


----------



## crapback

I was wondering if anyone else was going to have a listen to the 1208's. 
	

	
	
		
		

		
		
	


	




 I know it's only an 09 zero, but with the 797brz's in the dac and the 1208's in the amp it sounds pretty sweet. In music I have been listening to for years I keep hearing things I didn't know were there. I just made myself a set of cables for my 650's using some belkin pureav 18ga speaker wire and besides the amazing improvement(I'm completely floored and it only cost me about $25 worth of parts) it's opened up a whole new level of paranoia for me. 

 I listen to a lot of bands like Front Line Assembly, NIN, KMFDM and trip hop bands like Goldfrapp and Portishead. They all use a lot of effects and samples and noises that make me think something is wrong with my system. I keep checking to see if my cables are plugged in all the way, if they make noise when i wiggle the connections. I'm glad there isn't anyone else around to see me. 
	

	
	
		
		

		
		
	


	




 I can hear all the little clicks, taps, and squeaks in the orchestra pit too. I swear I can hear someone sneeze in my masterworks recording of Dvorak's Symphony No.1 in C minor.


----------



## cobaltmute

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I have never tried the LMH6643. I will have to review the specifications
 It depends on the circuit and task but I usually prefer the dual 710HA to the single 720HA. I have them both in adapters and they are some of my favorites AD parts are also very good for audio._

 

The LMH6643 is the choice for the low power Mini^3, which is why I chose it for my DAC running at +-2.5V. You have to watch that it can get unstable though.


----------



## leeperry

I see everyone gets his LT samples but me 
	

	
	
		
		

		
		
	


	




 luckily I got one pair of 1364 and 1361


----------



## ROBSCIX

Quote:


  Originally Posted by *cobaltmute* /img/forum/go_quote.gif 
_The LMH6643 is the choice for the low power Mini^3, which is why I chose it for my DAC running at +-2.5V. You have to watch that it can get unstable though._

 

I have some circuit coming up where I think I may be able to use this. I have worked with unstable opamps before so that is not that much of a problem.


----------



## crapback

My 1361's just arrived today. Right out of the bag they have great bass impact, really nice detail and an interesting soundstage. It's like they put an arena inside my head. The vocals are in the middle of my brain while the instruments are all nice and open and separated. I'll give these some time to see where they take me.


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_My 1361's just arrived today. Right out of the bag they have great bass impact, really nice detail and an interesting soundstage. It's like they put an arena inside my head. The vocals are in the middle of my brain while the instruments are all nice and open and separated. I'll give these some time to see where they take me. 
	

	
	
		
		

		
		
	


	


_

 

LT has some great opamps for audio. Are the the only LT units you have?
 The LT1057's are alos great for audio according to posted testing.


----------



## crapback

I have many LT opamps. 1028's, 1057's, 1113's, 1124's, 1208's, 1355's, 1358's, 1361's, 1363's, 1364's, 1469's and those are just the dip8's. I have some others that i need to put on some browndogs when I get a chance. I'm pretty happy with my 797brz's in the dac of my zero so all the opamps I try in the amp. The 1208's are my favorites so far. I tried the 1057's but they either need some time or they don't work well in my zero's amp. The soundstage was more like a practice room than a stage. I may not even get to spend more time with them once my audio-gd opa's arrive. I should have another week or two to play around until then.


----------



## crapback

One of the 1363's that showed up yesterday had one of the pins bent pretty bad. I straightened it out fine and put it in my amp but it didn't work. It made a nasty buzz and scared the crap out of me though. The shipment I got wasn't packed in any of those tubes, they were just loose in the anti-static bags so a few of them had bent pins. One pair of undies down and that's where I'm gonna stop. No more bent pin opamps are goin in my zero. I don't want to have to replace this thing with a compass. I want to move up to either the dac19/c2c combo or save up for the ref1/phoenix combo. I think the 1361's are gonna stay in here until my hdams arrive. 
	

	
	
		
		

		
		
	


	




 Oh ya. Hi Andrea.


----------



## leeperry

Quote:


  Originally Posted by *passed away* /img/forum/go_quote.gif 
_Creep silently on my back, and finish me..._

 







 Andrea, you seem like a very nice fellow..why do the older members hate you so badly?

 they say you've been stalking them and what not 
	

	
	
		
		

		
		
	


	




 are you banned on all the DIY forums? why don't you create a thread on diyaudio.com? would be a lot easier


----------



## crapback

NOOOOOOOOOOOOOOOOOO!!!!! You killed a house centipede!!! One of the very few predators of the cockroach. Now you are doomed to spend eternity mopping Star Jones' back fatfolds clean.


----------



## ecclesand

Did we have to bring bugs into this thread? Now I'm checking under my desk for any little nasties that may be lurking.


----------



## Cynips

What's wrong with bugs?


----------



## SpudHarris

Ordered my OPA1611 samples this evening 
	

	
	
		
		

		
		
	


	




 Haven't rolled anything for a week or so as I was on vacation and only took the P3+ without any other chips. So I'll be dropping out the TO99 47910's tonight to see if I can get synergie with my newly aquired JH13 Pro's, everything I rolled previously was based upon W3 listening....... and so it begins again.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Haven't rolled anything for a week or so as I was on vacation_

 

one week on vacation w/o rolling? Andrea will not be proud! 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Did we have to bring bugs into this thread? Now I'm checking under my desk for any little nasties that may be lurking.
	

	
	
		
		

		
		
	


	


_

 

well...might as well look *ON* the desk


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_One of the 1363's that showed up yesterday had one of the pins bent pretty bad. I straightened it out fine and put it in my amp but it didn't work. It made a nasty buzz and scared the crap out of me though. The shipment I got wasn't packed in any of those tubes, they were just loose in the anti-static bags so a few of them had bent pins. One pair of undies down and that's where I'm gonna stop. No more bent pin opamps are goin in my zero. I don't want to have to replace this thing with a compass. I want to move up to either the dac19/c2c combo or save up for the ref1/phoenix combo. I think the 1361's are gonna stay in here until my hdams arrive. 
	

	
	
		
		

		
		
	


	




 Oh ya. Hi Andrea._

 

Yes, I would be very uneasy with a opamps that looks like it has taken a beating with bent pins etc. However you never know until you actually test it. Maybe a small opamp test circuit or simple amp circuit? I have been thinking of building one mysellf. Give us your opinions when the HDAM's arrive.


----------



## crapback

Those bugs can't be real, right? If they were the scifi channel would have made about 500 movies about them. 

 I've used a couple other opamps that had bent pins but not bent like that 1363 was. It was bent upwards right on the side of the chip. I've had a few with the thin parts of the leads bent and they worked fine after being straightened. 

 I was listening to infected mushroom's bp empire when I swapped in the 1363's. A quick BZZZZZ! after turning my zero back on and that was one pair of undies down. I put my 1361's back in and turn infected mushroom back on and the sound seemed fine, no static, no hum, no more BZZZZZZ!. Then track 4, bp empire, ended. Then nothing. I looked to see if winamp had stopped. Nope. It was still playing. I thought my zero had poo'd itself. There went pair of undies #2. Thank the FSM himself, it wasn't my zero. Now I need to rerip that disc, and go wash some undies.


----------



## leeperry

yeah, I also asked LT What they would ship DIP8 chips w/o proper packing...they don't care, and they ship them so damn slowly...I've been awaiting my LT1057 for 2 months now, maybe they'll show up someday. the LT guy told me that DIP8 chips are becoming rare these days, and if Singapore cannot source them...as they send chips to the local office once a month, it might indeed take forever 
	

	
	
		
		

		
		
	


	




 I usually was lucky w/ bending them right in place...but did you try the OPA2132P? this one sounds seriously good to me


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_one week on vacation w/o rolling? Andrea will not be proud! 
	

	
	
		
		

		
		
	


	


_

 

Haha, yeah I missed not messing about last week but to be truthful I find myself becoming obsessed by the whole rolling thing. I enjoyed listening to the same chipset for a week, my ears became acustomed to the signature. I will try to listen for longer before swapping out Opamps in future.

 I have just got an AD8959 and a couple of LT1028's to tryout.

 Don't flame me but about the Andrea thing....... but I'm not a fan as I don't think he brings anything to this thread and I personally wouldn't follow a single recommendation as an hour later it would be different again 
	

	
	
		
		

		
		
	


	




.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Don't flame me but about the Andrea thing....... but I'm not a fan as I don't think he brings anything to this thread and I personally wouldn't follow a single recommendation as an hour later it would be different again 
	

	
	
		
		

		
		
	


	




._

 

haha, I was being sarcastic...Andrea is the most rolling obsessed person I have ever found on any forum, so this was a simple joke 
	

	
	
		
		

		
		
	


	




 and joke aside, next week I'll be getting a Corda Arietta...that also has a bunch of single DIP8 op-amps, meaning "more rolling!!!" yeah baby, LT1363 cumin'at 'cha


----------



## crapback

I'm ticked that one of my 1363's is borked. The stats are real close to the 1361's i'm loving right now but the current output is almost double. Not sure how that would work out. I'm gonna check to see if I ordered them in soic's.


----------



## acvtre

I was wondering how do you test the set ups. Do you use it for days or can you hear immediately the difference? Do you use particular songs?


----------



## SpudHarris

Quote:


  Originally Posted by *out of ideas* /img/forum/go_quote.gif 
_We could speak Italian, but let's be correct...


 Yes I do hear the difference immediately. I like to keep each opamp only a short time, but swap them often to make sure I got it right 
	

	
	
		
		

		
		
	


	




 Let's say that my method is influenced by my restlesness... but it works. I don't like to get too addicted to a certain opamp. Things should be heard immediately, without strain..._

 

Doesn't matter what you speak, your posts will be gone soon.....

 To appreciate the subtle differences in Opamps all will not be revealed immediately and that is fact. I would suggest to Acvtre that you have a playlist of your most favourite tunes as I do, tunes you know and love! When you roll your Opamps you will then be able to tell if the differences are a positive or negative thing.


----------



## SpudHarris

Double post, sorry!


----------



## cobaltmute

I agree with SpudHarris. Inital impressions are fine but listening over a period with music you know well is the only way to really tell if somethings is good. 

 For example I thought the LME49721 was pretty good to start in my DAC but after an hou of listening I knew it wouldn't last


----------



## acvtre

OMG, how could it be? out of ideas was a brand new member and now is banned.


----------



## leeperry

hehe, well it took me FOREVER to find final settings I like for my HTPC(color gamut conversions/avisynth scripts/Reclock settings/multichannel > binaural downmixing/etc etc)....choosing an op-amp is not quite an easy task either.

 so I'm the only one who likes the OPA2132P? I'm getting new gear next week anyway, and I found the STX to be very picky..and not liking high GBW op-amps, so my next set up might yield completely different results. the AK4396 only uses buffers, no I/V apparently.


----------



## SpudHarris

Quote:


  Originally Posted by *acvtre* /img/forum/go_quote.gif 
_OMG, how could it be? out of ideas was a brand new member and now is banned._

 

I got sucked in by that also a while back. 'Out Of Ideas' was exactly that. A banned member for ages (Andrea) re-inventing himself and hopefully *'Out Of Ideas'.*

 You should read all this thread from the begining...........


----------



## crapback

I'm listening to a pair of 2132pa's right now and they do sound pretty good. The soundstage is rather narrow and the stereo separation isn't very good in my zero. It's a pretty in my face sound. AC/DC sounds really good with them. Great rock opamp IMO but I'm still partial to the 1361's for now. The 1361's stereo separation can be a little too wide for some rock music but I love it with electronic and especially with industrial.


----------



## leeperry

why PA? you're a victim of subconscious high level ethics ?


----------



## crapback

ROFL
	

	
	
		
		

		
		
	


	




 Good thing I wasn't taking a drink when I read that. I used to love the letter people and pa is more letters than a.


----------



## acvtre

Is LT1078 a good amp?


----------



## majkel

I don't know, however I settled down with my favorite from the past - LT1028ACN8. The final battle with the OPA228P showed its supremacy. The sound has more body, fluence and soundstage range. The OPA228P seems to be more spatial but sounds are too focused, and lack body. Also, with the LT1028 I have the feeling of flying with the GS1000 on my head, as it was in a system with GamuT CD-3. BTW, Cirrus Logic recommends the LT1028 as the unbalanced output op-amp. 
 For those who know the LT1028C*8 - the ACN8 suffix versions is more fluent, spatial and complete. The LT1028CN8 compared directly is on the flat and dry side of things, preserving true tonality.


----------



## 12Bass

Haven't given them a critical listen for a while, though I seem to recall that the OPA827 might be a bit warmer in the midrange than the OPA211 which might be a bit more on the open/transparent side.


----------



## leeperry

my OPA1611/1612 just shipped! hopefully they'll do wonders on my Prodigy HD2 Deluxe 
	

	
	
		
		

		
		
	


	




 Apparently the THS4032 already works great on it, and it comes stock w/ two OPA2134 + one OPA2604...I think majkel recommended the later several times.


----------



## ecclesand

Excellent....just got a shipping notice from TI that the much anticipated 1612AID has been shipped. I just got my brown dog adapters so when the 1612 gets here I'll be able to solder them up and give them a listen.


----------



## SpudHarris

Waiting for mine to ship..... are we going to find the holy grail in the OPA1611/12?


----------



## leeperry

some ppl seem rather obsessed about metal caps 
	

	
	
		
		

		
		
	


	




AndAudio.com &bull; æª¢è¦–ä¸»é¡Œ - è€³æ“´èª¿éŸ³è¨˜(Arietta, SOLO, Battery Cute II, HA-11)

 some of them are larger than TO99, though?!

 I can't really read what they put in the Arietta on top?! and I don't think that the nichicon caps are stock, I hope not 
	

	
	
		
		

		
		
	


	




 I was told that for rolling op-amps in the Arietta, I'd better be careful:

  Quote:


 you have to use single bipolar opamps in it, like the LT1363 or LME49710. If you use FET ones like the OPA132 you could damage your headphones.


----------



## joe_cool

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_some ppl seem rather obsessed about metal caps 
	

	
	
		
		

		
		
	


	


_

 

Actually some ppl are obsessed about vacuum tubes, silver-plated copper interconnects, NOS DACs, RFI and wood cabinets. It's just part of the placebo response and the way expectations affect our perceptions.


----------



## Robin W.

Well I didn't get my opa1612's so I soldered up 4 pcs of opa1611 on a pair of dual so8 to dip adapters and I have to say the first thing I noticed is the noise floor simply vanished... before it was LOW, you had to turn up the volume to max to hear any static at all. Now it's just gone, I had to double check the amp was plugged in.
 After some very short listening, these things will have to be on for awhile before I really make judgement, but they've got a lot of detail (maybe a tad bright(using HD650's), but don't hold me to that they are barely an hour old).. I'll have to desolder something off an so8 to dip so I can put the 5th one in the ground channel for testing.

 Looking forward to hearing other peoples impressions of the 1611/1612.


----------



## joe_cool

Not wanting to be critical, but semiconductor devices have pink noise (hum/hiss) and "popcorn" noise. Resistors have white (johnson) noise. Radios have static.


----------



## Robin W.

Quote:


  Originally Posted by *joe_cool* /img/forum/go_quote.gif 
_Not wanting to be critical, but semiconductor devices have pink noise (hum/hiss) and "popcorn" noise. Resistors have white (johnson) noise. Radios have static. 
	

	
	
		
		

		
		
	


	


_

 

lol!
 I shall update my "noise" as slight hiss.
 However I am enjoying these new opa's I'm not sure if it will reach a point to replace the 720HA's as the clear favorite for my application longer term testing required.


----------



## leeperry

don't you think there's something funky in the 720HA mids? something's missing I think, and the OPA2132P is far grainier and detailed in that very section that's missing on the 720HA, I agree w/ Andrea on this one.


----------



## joe_cool

Quote:


  Originally Posted by *rwaudio* /img/forum/go_quote.gif 
_lol!
 I shall update my "noise" as slight hiss.
 However I am enjoying these new opa's I'm not sure if it will reach a point to replace the 720HA's as the clear favorite for my application longer term testing required._

 

Thanks for your understanding.

 On the subject of LME49720HA I recently ordered a set of 5 and Brown Dog adapters to use in comparison to my current favorite LM4562NA. If there is any significant improvement I will be delighted.


----------



## ecclesand

I received some more LT samples and will be trying them over the next week or so. I replaced the LT1208 with the LT1507. The LT1507 is smooth while maintaining a lot of punchiness. For me, it's still the one to beat.


----------



## 12Bass

Do you mean LT1057???


----------



## gurubhai

LT1028 - Is it single or dual channel ?


----------



## majkel

A good practice is elimination of wrong op-amps. You have to find something incorrect in sound and disqualify the op-amp on this basis. For instance, I've always perceived the OPA211 as collapsing the soundstage in a strange way and sounding like it's high resolution was available only at level of your ears. The AD797BRZ also makes a slight distortion which the LT1028ACN8 doesn't do. The LT1028 soundstage is wider in the Y-axis, too. My long time favorite OPA228P seems to build sounds from a strange, nicely colored matter but doesn't give impression of fluency. It's more of pure holography without body. The OPA827 is pretty nice but it's soundstage is a bit limited, ends too fast when looking further. The same is with THS4032 but this one is on the bright side of things instead of colorful warm. I agree the OPA827 is overall better than the OPA211.


----------



## Pluto2

Hi Majkel,

 Any dual chips you would recommend?


----------



## leeperry

well, I don't think LT will ever send me anymore samples and the THS4032 seems to be very bright indeed...I really can't stand bright op-amps 
	

	
	
		
		

		
		
	


	




 so at the end of the week, I will ask a friend to put these on browndog's for me :
 -OPA211
 -OPA1611

 hopefully these will work out nicely on the AK4396 of the Prodigy HD2 Deluxe 
	

	
	
		
		

		
		
	


	




 the OPA827 are supposed to ship in a few weeks...and I got a bunch of OPA132U, can't remember if these are supposed to be a major improvement over 2132P?


----------



## leeperry

Quote:


  Originally Posted by *exhonerated* /img/forum/go_quote.gif 
_the OPA132UA [..] is a newly revised version of the original OPA2132...

 P.S. My favorite dual opamps: LT1678 (based on the LT1677) and LME49723._

 

oh ok, I stand corrected! I'm getting lost in all these refs 
	

	
	
		
		

		
		
	


	




 too bad the max number of samples is 5, I'd need 6 to get 3 nice DIP8 dual chips...the AK4396 doesn't have any I/V apparently, it's got 3 dual buffers..
 yes, I've ordered some LT1678/LT1677...maybe they'll show up 
	

	
	
		
		

		
		
	


	




 I'd rather stay clear from the LME from now on, too bright/bass tame to my ears...I don't think I will get the LME49722 installed either


----------



## leeperry

BTW, the op-amps on the Prodigy 2 are fed w/ ±9V..rather low?


----------



## Robin W.

Quote:


  Originally Posted by *exhonerated* /img/forum/go_quote.gif 
_Why on earth don't you say a thing about this OPA1611... afraid of being derided later? Slow apprehension? Please, dare..._

 

I didn't want to say anything after 1 hour of listening because sometimes op-amps burn in and sound different after a short period of time. So here are some comments after 2 1/2 hours of listening + 9 hours of being "on" low level music playing, now another 1/2 hour of listening.

 The op-amp has smoothed out quite a bit without loosing detail. I'm sure a lot of it comes down to application but it still isn't at the level of the LME49720HA in my application (but in all fairness the amp was designed around the lme49860, and tweaked and tuned to sound good) The 720HA simply builds on that sound giving more detail etc. All other op-amps I've tried drastically change the sound characteristics of the amp and trade off something. 

 I'm not saying the 1611 is a "bad" op-amp, I am saying I think it would be quite amazing in a simpler circuit or better yet an amp that is designed around it, instead of an amp designed around a completely different op-amp.

 So my early recommendations are this:
 If you have an amp/sound card that's using the LME49720/LM4562 and you like the sound then the 720HA might be your ticket to sonic bliss. If you have this setup and don't like the sound I would say give the 1612 a try, it really is very good based on first impressions it just doesn't work in my application.


----------



## SpudHarris

I'm struggling to find anything comparable to the 710HA's in my Ibasso P3+. This amp was made for rolling so not built around a specific Opamp. I'm using Stacked Buf634's and the DIP version 710's in G/V and man it sounds just awesome with my JH13 Pro's (6 drivers in each ear 
	

	
	
		
		

		
		
	


	




)


----------



## Robin W.

Quote:


  Originally Posted by *joe_cool* /img/forum/go_quote.gif 
_Thanks for your understanding.

 On the subject of LME49720HA I recently ordered a set of 5 and Brown Dog adapters to use in comparison to my current favorite LM4562NA. If there is any significant improvement I will be delighted._

 

I missed this reply, but as I said above if you already like the sound of the LM4562 (some do, some don't) then I think you will love the 720HA
 One of my customers that had a stock amp borrowed the "HA" version for a day and came back stating that he "NEEDS" that. He said the sonic improvement was unmatchable in anything related to his speaker setup. His example was $10,000 cables that made 1/4 the improvement of the 49860 to 49720HA swap.

 The one thing that keeps getting ignored is the application, people give generalized results of how a certain op-amp sounds as if it will sound like that in every device it is plugged into. That is simply not the case and should be taken into consideration. 

 The analogy would be that every headphone (HD650, HF2 etc) will maintain the exact same sound regardless of the source it is plugged into. I'm sure we all know that is simply not the case. The total package must be considered. When people praise or bash a headphone they typically state what amp was used.
 So when people praise or bash an op-amp the application is just as important as the results. And very meaningless without it.

 just my rant


----------



## Robin W.

Quote:


  Originally Posted by *exhonerated* /img/forum/go_quote.gif 
_You haven't said much (or anything) about the sound of this OPA1611 yet. 
	

	
	
		
		

		
		
	


	




 No problem, I should also receive them soon.


 Try the LT1677 and LT1678..._

 

You are correct and I applogize but it would be like reviewing HD-800's when your source is a fisher price walkman. It simply does not fit the application and the results would not be accurate. 

 The comments that you can take from my experience are the dead quiet noise floor. Atleast in my amp where input bias currents were taken into account. This op-amp has a lower noise floor than the LME49720HA which is already very good.

 The detail is also VERY good, I would call it to a good sounding AD8620. It has the same level of detail but is much smoother and nicer to listen to atleast with the HD650's.

 There is something off about the overall balance, perhaps my amp compensates for problems with the LME's and the 1611 just doesn't work in my circuit. 

 I think in the near future there will be some amps/cards/whatever that benifit greatly from this op-amp. I don't think it's the new best thing out there. But I do think it's great for the price and will shine in the right application.


----------



## ecclesand

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Do you mean LT1057???_

 

Ooops...yeah, LT1057. I need to stop rolling these damn things!


----------



## leeperry

BTW, for the PCM1792 peeps: http://www.ti.com/lit/gpn/pcm1792a

 page34:
  Quote:


 The operational amplifier recommended for the IV circuit is the NE5534, and the operational amplifier recommended for the differential circuit is the Linear Technology LT1028, because its input noise is low 
 

TI recommends to use the LT1028


----------



## Pluto2

Hi rwaudio,
 Any chance you would have the opA221 on adaptor to compare with the opa1611? Skeptics say that opa1611 is just a lower grade opa221.....could that be true? 
 I wonder if opa2134 and opa2132 are like that too......


----------



## leeperry

Quote:


  Originally Posted by *exhonerated* /img/forum/go_quote.gif 
_It can't sound like the OPA211, because its numbers are different._

 

what if the model numbers are chosen randomly? does that break your numerology theory altogether?


----------



## Kuze

Damn it, i made an order with nationals but didn't know you could get the samples completely free if you use emails other than gmail and hotmail.
 I used gmx mail and its completely free you dont even have to pay for shipping and handling.


----------



## 00940

Don't feel bad about buying stuff: http://www.head-fi.org/forums/f6/sam...estion-440463/


----------



## Robin W.

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Hi rwaudio,
 Any chance you would have the opA221 on adaptor to compare with the opa1611? Skeptics say that opa1611 is just a lower grade opa221.....could that be true? 
 I wonder if opa2134 and opa2132 are like that too......_

 

Hello Pluto2,

 I do have some 2211's that I mounted (in my setup I have one dual op-amp per channel) I could compare the two and see if I can tell the difference.
 That would be two 2211's vs four 1611's so not entirely direct, but pretty darn close. Is there a headphone from my sig that you would prefer the comparison based on?


----------



## ecclesand

I received the LT1678IS8 today, mounted them on a BD adapter, and installed them in my Peridot DAC. I let them burn in for around 2 hours before having a listen. Very nice! Deep bass, good impact, forward mids, extended yet smooth highs. The detail is incredible.

 I need to give these a couple days, but I think I may have found something to beat the LT1057.

 I also mounted an LME49720HA on a BD adapter and tried it. I need to give it more time, but I wasn't immediately impressed with it as I was with the LT1678. There is just something about these LT opamps.


----------



## Pluto2

Hi rwaudio,

 Just wanted to know how they'd fare between each other and so in any setting should be of interest to know : )

 Thanks for the asking.


----------



## majkel

Maybe someone wants to say offering free samples is immoral?


----------



## majkel

Sure as nobody explained so far the purpose of different names for the same chips. Maybe it's a marketing trick to sell more of them to flavor seekers?


----------



## SpudHarris

I have just soldered up the LT1677's so will be auditioning tonight, hope you're right Andrea as I had to pay for them hehe


----------



## ROBSCIX

Post your opinions when your done.


----------



## Zaubertuba

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well, I read majkel saying that single op-amps usually yield better results than dual, simply because nothing's shared between the 2 channels?!..._

 

 Quote:


  Originally Posted by *Filburt* /img/forum/go_quote.gif 
_You're certainly welcome to try the single to dual route but I don't care for the layout on those adaptors. I'm not sure it would materially improve crosstalk, though. I don't know what majkel means by "nothing's shared"; if you're using a single to dual adaptor, you're still using the same source of power for both and issues such as common mode signals are still present...._

 

Sorry to dredge up ancient postings, guys, but I'm interested in experimenting with rolling opamps on my balanced a47. I'm currently running OPA2134's in it at +-12.5v. I'm using a cheap switching computer power supply (it's variable from 9-25v) feeding a TLE2426/BUF634 rail-splitter. I actually like the warmth of the 2134's but have severe upgraditiss when greater detail can be had, and am really looking for a broader soundstage. Tangent posted this in a (much more ancient) thread:

  Quote:


  Originally Posted by *tangent* 
_A big contributor to a wide soundstage is a high channel separation. There are a couple of things influencing channel separation, including:

 1. The op-amp (single or dual)

 2. Routing of wires on the board (do you have paralleled wires from different channels?)

 3. Impedance of the ground path (alkalines vs. rechargeables, earth ground vs. virtual ground, various virtual ground strategies vs. each other...)_

 

FWIR, it seems like the DIFET opamps that are so popular on here may be a good bet, but the price adds up really quickly when my circuit requires 4 duals (or 8 singles 
	

	
	
		
		

		
			





). Where soundstage is concerned, could I get reasonable results "browndogging" or otherwise adapting my circuit for cheaper, but still well-regarded singles? Or would I be better off biting the bullet and getting 4 dual DIFETs?


----------



## crapback

In my zero, I get the best soundstage with AD797brz's in the dac and 2 LT1361's in the amp section. I've tried a number of opamps in the amp and the 1361's have by far the best stereo separation but that's just in my lowly zero.


----------



## murrays

Quote:


  Originally Posted by *Zaubertuba* /img/forum/go_quote.gif 
_Sorry to dredge up ancient postings, guys, but I'm interested in experimenting with rolling opamps on my balanced a47. I'm currently running OPA2134's in it at +-12.5v. I'm using a cheap switching computer power supply (it's variable from 9-25v) feeding a TLE2426/BUF634 rail-splitter. I actually like the warmth of the 2134's but have severe upgraditiss when greater detail can be had, and am really looking for a broader soundstage. Tangent posted this in a (much more ancient) thread:

 FWIR, it seems like the DIFET opamps that are so popular on here may be a good bet, but the price adds up really quickly when my circuit requires 4 duals (or 8 singles 
	

	
	
		
		

		
		
	


	




). Where soundstage is concerned, could I get reasonable results "browndogging" or otherwise adapting my circuit for cheaper, but still well-regarded singles? Or would I be better off biting the bullet and getting 4 dual DIFETs?_

 

There are more subtle issues than just the quoted "separation" of a dual device. (See if you can track down Walt Jung's articles on audio op-amps). There are many paths that act as inputs and can couple signals. The power supply is a common one. A dual device must share its power supply - that is one thing you cannot split. So you must do the best you can with regulation and bypassing. Any ripple or noise imposed on a power rail by one half can affect the other half. Another subtle coupling path is thermal effects. Also there is layout, as mentioned by Tangent.

 If you decide to replace a dual device with two singles you will not reap full benefit unless you can also implement independent power supplies. That can be done with local regulators near each op amp. The best / most extreme separation is to go full "dual mono" - two independent mono amplifiers with nothing shared (well, maybe the transformer).


----------



## majkel

The dual op-amps have some common circuitry like current mirrors which may cause some crosstalk, and another source of crosstalk is proximity of the circuits in the silicon die. BTW, it's audible when you try 2x OPA228 against OPA2228. Also, some more sophisticated op-amps don't appear in dual packages due to power density, die dimensions or guaranteed parameters. 
 Dual op-amps are often intended as differential amplifiers of a single signal, and in those cases the crosstalk is something you don't care for. Only cheapest DACs and CD players make use of one dual op-amp for both channels, in normal cases it's a separate chip or chips for each channel.


----------



## Cynips

Just got my OPA1612AID's delivered (much to my surprise as I was told they were backordered to Sep 15), so now I need to set my soldering skills to the test. Anyone have a link to a good soldering guide for these things? Or maybe can give me a few pointers as to what to think about?


----------



## leeperry

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Only cheapest DACs and CD players make use of one dual op-amp for both channels, in normal cases it's a separate chip or chips for each channel._

 

I guess the I/V on the PCM1792 is not shared? one DIP8 chip/channel? only the buffer would?

 and I need to document myself about the AK4396 buffers, there's 3 of them on my card...so the last one has to be shared.

*PS:* I'm glad to read that the AK4396 has a fixed 128X oversampling rate...it's 64X by default on the PCM1792, it can be raised to 128X for <96KHz but most implementations don't seem to bother(Asus included).


----------



## SpudHarris

Well I spent an evening in the company of 2 # LT1677's last night and again today but not so critically. I have to say of the LT OpAmps I've sampled I like this one the most. It's very detailed but not harsh or fatiguing, well suited to the Psy/Electronic Genre (Shpongle, Flooting Grooves, Dymons, Bluetech, Kaya Project etc...). Not overly expensive either (£5 each) for what they are. Veeeeeery Nice


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_The dual op-amps have some common circuitry like current mirrors which may cause some crosstalk, and another source of crosstalk is proximity of the circuits in the silicon die. BTW, it's audible when you try 2x OPA228 against OPA2228. Also, some more sophisticated op-amps don't appear in dual packages due to power density, die dimensions or guaranteed parameters. 
 Dual op-amps are often intended as differential amplifiers of a single signal, and in those cases the crosstalk is something you don't care for. Only cheapest DACs and CD players make use of one dual op-amp for both channels, in normal cases it's a separate chip or chips for each channel._

 

I have found the same based on my testing and others I have spoke with on the subject. Single channel units used in a dual channel configuration for instance will sound better then it's dual channel brother. As you said though many of the higher grade opamps dsigned or meant for audio only come in single channel versions.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I have found the same based on my testing and others I have spoke with on the subject. Single channel units used in a dual channel configuration for instance will sound better then it's dual channel brother. As you said though many of the higher grade opamps dsigned or meant for audio only come in single channel versions._

 

Interesting. Does anyone know what the single version of the LT1057 is? Is it the LT1007? I want to buy some of the single channel equivalents of the LT1057 and LT1678 since they sound the best to my ears.


----------



## Cynips

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_Anyone have a link to a good soldering guide for these things? Or maybe can give me a few pointers as to what to think about?_

 

Did some research, so in case someone is interested here's what I found with a link to a bunch of video tutorials even


----------



## ROBSCIX

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_Just got my OPA1612AID's delivered (much to my surprise as I was told they were backordered to Sep 15), so now I need to set my soldering skills to the test. Anyone have a link to a good soldering guide for these things? Or maybe can give me a few pointers as to what to think about?_

 

Soldering SOIC are pretty easy once you get a good technique going.

 I usually use a touch of Quad Eucetic solder to the one corner pad on the adapter..just a bit.
 Then put the opamp in position. Touch the pad with the solder, this should tack the opamps down. 
 If it doesn't line up properly, heat and move the opamp into proper position.
 Proceed to go to the other side, criss, crossing the corners, then solder down the rest.

 I prefer Cardas solder for these as it has a very low melting point and you can get good joints very fast.
 Also seems to work the best for my needs anyway.
 Heat the joint the touch quickly with the solder -a dab will do you. Simple once you get the idea and the movement down.
 Poeple have different methods but it is usually a revamp on the above technique.

 Make sure you keep pin one oriented properly and inspect your work afterwards for solder bridges or other poor joints. If everything looks good then test the unit out.

 I can solder a SOIC unit in under a minute. I have had lots of practice with the iron though. I think some other will also offer you pointers.


----------



## Cynips

Thanks for the input ROB. Helpful as always!

 The guy in that video tutorial I linked to is actually doing a SOIC8 opamp amongst other things, so I recognize some of what you're describing. I'll take the solder make suggestions into consideration and do a trip downtown tomorrow since I need to pick up a few other things anyway.


----------



## ROBSCIX

Everybody who solders seem to have their favorite brands. I use Cardas Quad Eucetic for my audo circuits. Mainly because for me, it is so easy to work with and melts at very low temp compared to others making it great for these smaller circuits.
 However, use whatever works for you.


----------



## Robin W.

My opinion of LT1057...
 Quite detailed, but VERY relaxed/laid back sound using HD650's. I fell asleep.
 More engaging but remaining smooth with HF2's.
 Not really my taste overall, however I imagine this could provide an amazing synergy with the right 'phones.


----------



## ecclesand

Quote:


  Originally Posted by *rwaudio* /img/forum/go_quote.gif 
_My opinion of LT1057...
 Quite detailed, but VERY relaxed/laid back sound using HD650's. I fell asleep.
 More engaging but remaining smooth with HF2's.
 Not really my taste overall, however I imagine this could provide an amazing synergy with the right 'phones._

 

It sounds fantastic with the RS2.


----------



## crapback

I like to use my helping hands Amazon.com: Xacto X75170 X-tra Hands with Magnifier: Home Improvement to hold the chip in position on the adapter. I use a pair of tweezers to place the chip and then carefully place it in the clip. I have some quad eutectic but I haven't used it yet. For now it's just plain old kester. 

 Things have changed on the opamp front. I soldered in a bunch of russian petp http://cgi.ebay.com/0-047uF-160V-5-P...d=p3286.c0.m14 bypass caps in my zero and it is a much different animal now. I'm still running the 797b/1361 dac/amp combo but I think I'm going to have to test out everything all over again. I still have some time to play around with opamps. I just got my ems tracking number from susan at audio-gd for my hdams. I'm having way to much fun with this, even for a geek like myself.


----------



## Cynips

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I like to use my helping hands Amazon.com: Xacto X75170 X-tra Hands with Magnifier: Home Improvement to hold the chip in position on the adapter. I use a pair of tweezers to place the chip and then carefully place it in the clip. I have some quad eutectic but I haven't used it yet. For now it's just plain old kester._

 

That magnifier looks like it could come in handy. I'm at the age where I find my eyesight starting to deteriorate 
	

	
	
		
		

		
		
	


	



 And I certainly know how to use a pair of tweezers. Being an entomologist, I've dissected out the various mouthparts of insects less than a millimeter long. But that's using a stereo microscope with professional grade watchmaker tweezers.


----------



## leeperry

can't you reuse browndog's? they don't seem to be for single use?!

 I've just received my LT1677/1678, so I guess I'm not on LT's blacklist just yet...it's just that it's taking them forever to source some LT1057 to send me(DIP8 have become a rare commodity I was told 
	

	
	
		
		

		
		
	


	




)

 and my Arietta w/ its 4xLT1363(or 4xLM6171 stock) has arrived too


----------



## ROBSCIX

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_That magnifier looks like it could come in handy. I'm at the age where I find my eyesight starting to deteriorate 
	

	
	
		
		

		
		
	


	



 And I certainly know how to use a pair of tweezers. Being an entomologist, I've dissected out the various mouthparts of insects less than a millimeter long. But that's using a stereo microscope with professional grade watchmaker tweezers._

 

Use whatever makes your job easier. I have a set of those helping hands but I don't use them as much as you would think for this job. I am thinking of buying a jewellers loop for close inspection. Alternately, I may go with a USB micro and use that for close inspection.
 They seem smaller then they are as once you get your technique going right and using the proper tools you can do them with little trouble.
 The dual Soic8 to Dip8 are a bit hard as depending on the adapter you have to solder the pins between other pins.


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_can't you reuse browndog's? they don't seem to be for single use?!

 I've just received my LT1677/1678, so I guess I'm not on LT's blacklist just yet...it's just that it's taking them forever to source some LT1057 to send me(DIP8 have become a rare commodity I was told 
	

	
	
		
		

		
		
	


	




)

 and my Arietta w/ its 4xLT1363(or 4xLM6171 stock) has arrived too 
	

	
	
		
		

		
		
	


	


_

 

They are adapters, you solder on the chip and that is it. they are "re-usable in that you can remove and use them in whatever circuit you want. 
 If your talking about de-soldering and soldering on new opamps. Not recommended as they can be quite fragile and chances are you might pull off 1 or more of the pads. It is easier to just buy new ones.


----------



## leeperry

dang, it looks dead easy from the video tutorials!

 I've got some LM4562MA that will be used as guinea pigs I think


----------



## Kuze

Got samples from LT today comes in nice static bag and protection, LT1208.

  Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_dang, it looks dead easy from the video tutorials!

 I've got some LM4562MA that will be used as guinea pigs I think 
	

	
	
		
		

		
		
	


	


_

 

What video tutorials?


----------



## FauDrei

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Dual op-amps are often intended as differential amplifiers of a single signal, and in those cases the crosstalk is something you don't care for. Only cheapest DACs and CD players make use of one dual op-amp for both channels, in normal cases it's a separate chip or chips for each channel._

 

In CA DacMagic there are four N5532 used as differential amps for balanced outputs and two OP275 as buffers for unbalanced outputs.

 Any suggestions/recommendations for upgrading those 4 + 2 opamps?


----------



## leeperry

hehe, Andrea don't break a sweat just yet! 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *Kuze* /img/forum/go_quote.gif 
_What video tutorials?_

 

Tangent Tutorials


----------



## leeperry

.


----------



## ROBSCIX

@Cynips, have you considered the LT1057 TO-99's?
 I have been looking aorund for some new opamp modules to build and test and these are on my list also.


----------



## LingLing1337

I have an OPA2134PA laying around. Is it worth it to pop it into my Beresford? I have NE5532 in the line stage and THS4032CD in the HP out. Anyone know what kind of changes it would bring about?


----------



## ROBSCIX

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_I have an OPA2134PA laying around. Is it worth it to pop it into my Beresford? I have NE5532 in the line stage and THS4032CD in the HP out. Anyone know what kind of changes it would bring about?_

 

Try it out. Many would say the OPA2134 is an improvment. Try it out and see if it sounds good with what you have. 

 A Opamps can get to be a bit of hobby...


----------



## wsatia

I'm looking for an opamp configuration on my iBasso P3 (no plus) that would kinda give a warm sound, for use with my Livewires Triples (very sensitive I would think, and I've had problems with sound leaking at zero on the volume knob and some buzzing sound when using the AD8397, but it's not unbearable bad but I'd prefer to have opamps which don't have that buzzing sound if you guys know what causes it.

 So yup any suggestions on warm sounding opamps for the P3? Oh and I'd prefer to keep as much details and preferably increase the soundstage if possible!


----------



## SpudHarris

Quote:


  Originally Posted by *wsatia* /img/forum/go_quote.gif 
_I'm looking for an opamp configuration on my iBasso P3 (no plus) that would kinda give a warm sound, for use with my Livewires Triples (very sensitive I would think, and I've had problems with sound leaking at zero on the volume knob and some buzzing sound when using the AD8397, but it's not unbearable bad but I'd prefer to have opamps which don't have that buzzing sound if you guys know what causes it.

 So yup any suggestions on warm sounding opamps for the P3? Oh and I'd prefer to keep as much details and preferably increase the soundstage if possible!_

 

I like the OPA637's in my P3 for sure (won't work in my P3+). If you don't have the 637's I'd go for the following which is what I also run in my P3+

 LT1677's in L/R (I prefer Class A)
 Buf634 in Buffer Sockets (Hi-C)
 LME47910's in G/V

 Super detailed, high resolution but no glare just real hifi sound with my JH13's


----------



## ROBSCIX

Quote:


  Originally Posted by *wsatia* /img/forum/go_quote.gif 
_I'm looking for an opamp configuration on my iBasso P3 (no plus) that would kinda give a warm sound, for use with my Livewires Triples (very sensitive I would think, and I've had problems with sound leaking at zero on the volume knob and some buzzing sound when using the AD8397, but it's not unbearable bad but I'd prefer to have opamps which don't have that buzzing sound if you guys know what causes it.

 So yup any suggestions on warm sounding opamps for the P3? Oh and I'd prefer to keep as much details and preferably increase the soundstage if possible!_

 

I agree with Spud as the 637s can give some great sound provided they have the right circuit.
 Burr Browns may have a warmer signature that might suit you a bit better.
 Testing is the way to find out..


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Testing is the way to find out.._

 

x2

 And it's madatory when you have a P3 or P3+


----------



## ROBSCIX

I test everything I can and make up my mind after hearing what there is to be heard.


----------



## wsatia

Hmm do those companies give their samples internationally? Opamps really aren't cheap for me (just a student heh) and I live in Singapore, so I'm not sure if I can get samples? But thanks for the suggestions, I don't have ANY of the opamps you mentioned though  I have an AD8066, AD8397, AD845, OPA2132 in addition to the standard ones given with the P3. I'll try going for the SpudHarris combination first and see if I can pick up a 637 too


----------



## ROBSCIX

Just talk to people with the same unit as you have and get some ideas of what units people are testing out. 

 Use the units that you like the best.


----------



## SpudHarris

It's addictive though and with so many combinations I'm rolling all the time in search for the 'holy grail' combo. At present I'm stuck between LT1357's or 1677's both being superb but I think the 1357's are slightly more involving and musical. I like both with the same Buffer and G/V chipset.

 634 Hi-C Buffers
 LME49710's (G/V)


----------



## ROBSCIX

Yes, it can get to be a hobby in and of itself.


----------



## Currawong

I tried, once again, Majkel's suggestion of OP27s by popping a couple of OP27G in my Compass. Wonderful! Not as mushy as the 627s, not as flat and dull as the 49720 and the mids are perfect. The only problem is, I can't see anything but rather expensive OP27A/C online at TI. Any thoughts?


----------



## ROBSCIX

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_I tried, once again, Majkel's suggestion of OP27s by popping a couple of OP27G in my Compass. Wonderful! Not as mushy as the 627s, not as flat and dull as the 49720 and the mids are perfect. The only problem is, I can't see anything but rather expensive OP27A/C online at TI. Any thoughts?_

 

Are you refering to these->OP27

 Are you looking for something a bit more cost effective in this family?


----------



## wsatia

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_It's addictive though and with so many combinations I'm rolling all the time in search for the 'holy grail' combo. At present I'm stuck between LT1357's or 1677's both being superb but I think the 1357's are slightly more involving and musical. I like both with the same Buffer and G/V chipset.

 634 Hi-C Buffers
 LME49710's (G/V)_

 

Grr I can't seem to find the LME49710 on farnell, and I don't know where else I can get opamps from (without excessive shipping costs). Any other recommendations for opamps or places which I can get opamps from?

 How would I know if the 634 I'm looking at is a Hi-C one? Is this a 634 Hi-C buffer? This.

 And damn the 637's are REALLY costly, don't think I'll get them yet


----------



## SpudHarris

Quote:


  Originally Posted by *wsatia* /img/forum/go_quote.gif 
_Grr I can't seem to find the LME49710 on farnell, and I don't know where else I can get opamps from (without excessive shipping costs). Any other recommendations for opamps or places which I can get opamps from?

 How would I know if the 634 I'm looking at is a Hi-C one? Is this a 634 Hi-C buffer? This.

 And damn the 637's are REALLY costly, don't think I'll get them yet 
	

	
	
		
		

		
		
	


	


_

 

Ideally you should get these type. You'll need a TO99 to DIP 'Browndog' or similar adapter.

 The 634 Buffers are the standard DIP version on an adapter with a resistor (can't remember the value) between pins 1 & 4. Improvement in sound but runs batteries down quicker.


----------



## madwolf

You could compare LME49600 and BUF634. From the datasheet you could see that the LME49600 and BUF634 are the same part just by different manufacturer.


----------



## leeperry

this company is selling HUGE adapters: SIVAVA - SOIC8 (with socket 150 mil.) to DIP8 Adapter \ Universal & Willem EPROM Programmer

 I was hoping that they'd be solderless, but it doesn't seem to be the case.

 and when we talk about op-amps, it's good to take our headphones FR in account I think...the LME serie was totally unbearable for me trebles-wise on my Manufaktur DT770/600Ω, which is sibilant to death to begin w/ 
	

	
	
		
		

		
		
	


	




 but my cd1k(same drivers as cd3k) has a much much more laid back frequency response...bass is not boomy, sounstage is HUGE, trebles are just very relaxed....I'll have to think about it, but I don't need an extreme soundstage op-amp anymore, neither a very bassy either..I'll mount the LME49722 on adapters I think


----------



## wsatia

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Ideally you should get these type. You'll need a TO99 to DIP 'Browndog' or similar adapter.

 The 634 Buffers are the standard DIP version on an adapter with a resistor (can't remember the value) between pins 1 & 4. Improvement in sound but runs batteries down quicker._

 

Ah right, any idea how I'd get my hands on them cause I'm not too handy with my soldering skills yet heh


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Ideally you should get these type. You'll need a TO99 to DIP 'Browndog' or similar adapter.

 The 634 Buffers are the standard DIP version on an adapter with a resistor (can't remember the value) between pins 1 & 4. Improvement in sound but runs batteries down quicker._

 

In the circuit your talking about do you require single channel units?
 As the LME49710HA are single channel. Browndog has TO-99 to DIP8 adapters, do you use these for the LME49710?


----------



## SpudHarris

Yes, all the P3 and P3+ are Single channel sockets. L/R and G/V can also take dual opamps. Is that what you mean? I prefer the DIP 47910's in ground on the P3's. 

 I have rediscovered the AD823 this evening. I can understand why Graham Slee uses this in the Solo, man this is just fantastic!! Is there a dual version do you know??


----------



## ROBSCIX

Are you using the adapters on the Brown dog site for the LM49710's?


----------



## SpudHarris

For the HA's yes. I make my own Class A adapters for the standard DIP's.


----------



## ROBSCIX

Yes, I remember seeing a pic of them.
 I thought those models at Brown Dog were for dual channel TO-99 only.
 Good to know.


----------



## SpudHarris

Quote:


  Originally Posted by *wsatia* /img/forum/go_quote.gif 
_Grr I can't seem to find the LME49710 on farnell, and I don't know where else I can get opamps from (without excessive shipping costs_

 

? They do have them at Farnell LME49710


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Yes, I remember seeing a pic of them.
 I thought those models at Brown Dog were for dual channel TO-99 only.
 Good to know._

 

Here they are.... They don't cost the earth either.


----------



## ROBSCIX

Yes I have a few adapters from them. 
 I thought they were for use with the Dual channel TO-99's but I guess they would work for both.


----------



## wsatia

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_? They do have them at Farnell LME49710_

 

Ah right I was looking for them on the Singapore Farnell site though, and couldn't find it when I searched


----------



## ROBSCIX

The LME49710's are some great units you should definately get some to test out.


----------



## Cynips

Quote:


  Originally Posted by *rwaudio* /img/forum/go_quote.gif 
_Well I didn't get my opa1612's so I soldered up 4 pcs of opa1611 on a pair of dual so8 to dip adapters and I have to say the first thing I noticed is the noise floor simply vanished... before it was LOW, you had to turn up the volume to max to hear any static at all. Now it's just gone, I had to double check the amp was plugged in.
 After some very short listening, these things will have to be on for awhile before I really make judgement, but they've got a lot of detail (maybe a tad bright(using HD650's), but don't hold me to that they are barely an hour old).. I'll have to desolder something off an so8 to dip so I can put the 5th one in the ground channel for testing.

 Looking forward to hearing other peoples impressions of the 1611/1612._

 

Managed to solder the 1612AID's onto Brown Dog adapters - apparently successfully so since I've got some first impressions here:

 I agree that they might be a tad bright, but less so than the LME49860. And they're really detailed in a good way, something which I might attribute to the slightly prominent highs. But even deep bass seems detailed, or you could say textured and controlled yet powerful - not at all boomy or hollow.

 So, overall a very good opamp, fast and punchy with a huge soundstage, but I think I prefer the LT1057's still. I could have some oversight with the brightness in trade-off for that almost analytical detail and lovely bass.

 Also managed to put the 49720HA's on adapters as well as a pair of OPA2211AIDDA's, so I need to find some time to try these out as well. Not to mention that I got myself some Monster Turbines, making for something to compare my DT150's to. If nothing else, a useful exercise listening to different combinations 
	

	
	
		
		

		
		
	


	




.


----------



## ROBSCIX

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_Managed to solder the 1612AID's onto Brown Dog adapters - apparently successfully so since I've got some first impressions here:_

 

I am right behind you but I will be doing a new build in a few days. 

 Glad to hear positive feedback so far.

 How did the soldering go?


----------



## ecclesand

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_Managed to solder the 1612AID's onto Brown Dog adapters - apparently successfully so since I've got some first impressions here:

 I agree that they might be a tad bright, but less so than the LME49860. And they're really detailed in a good way, something which I might attribute to the slightly prominent highs. But even deep bass seems detailed, or you could say textured and controlled yet powerful - not at all boomy or hollow.

 So, overall a very good opamp, fast and punchy with a huge soundstage, but I think I prefer the LT1057's still. I could have some oversight with the brightness in trade-off for that almost analytical detail and lovely bass.

 Also managed to put the 49720HA's on adapters as well as a pair of OPA2211AIDDA's, so I need to find some time to try these out as well. Not to mention that I got myself some Monster Turbines, making for something to compare my DT150's to. If nothing else, a useful exercise listening to different combinations 
	

	
	
		
		

		
		
	


	




._

 

I pretty much experienced the same thing with the OPA1612. And, like you, I prefer the LT1057 over it and just about every other opamp I've tried (although the jury is still out on the LT1358CN8). In fact, I bought...yes, actually bought, a handful of the LT1057ACN8s for my other devices and for backups.


----------



## Cynips

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_How did the soldering go?_

 

It was a fun experience, trying to work with such small things. I think the tip of my iron is somewhat too clunky, but with a little help of the soldering braid I managed to clean it all up and get rid of the bridges. Made me a little worried that I might have heated the opamps too long, but it seems that was not the case.


----------



## SpudHarris

Is there a single version of the 1057??


----------



## 12Bass

Hmmm..... think I have LT1057 around somewhere and don't recall being that impressed. For FET, a bit better than a TL072 perhaps, but not as nice as OPA827 as I recall.


----------



## Cynips

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I pretty much experienced the same thing with the OPA1612. And, like you, I prefer the LT1057 over it and just about every other opamp I've tried (although the jury is still out on the LT1358CN8). In fact, I bought...yes, actually bought, a handful of the LT1057ACN8s for my other devices and for backups._

 

Cool, guess that maybe Linear's sampling program is beginning to pay off then? 
	

	
	
		
		

		
			





 For me, the LT1358CN8#PBF is no competition for the LT1057ACN8 though being a decent opamp.


----------



## Cynips

I currently have both LME49722MA and LT1678CS8#PBF here but only one pair of SOIC to DIP adapters. So I'm asking you guys for advice. Which should I go for first with testing in my Essence STX? I'll eventually order some more Brown Dogs though.


----------



## leeperry

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_LME49722MA_

 

0.00002% THD


----------



## ROBSCIX

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_It was a fun experience, trying to work with such small things. I think the tip of my iron is somewhat too clunky, but with a little help of the soldering braid I managed to clean it all up and get rid of the bridges. Made me a little worried that I might have heated the opamps too long, but it seems that was not the case._

 

My iron has a very pointed tip and I touch up the point before I do a build.
 I find the type of solder you use helps a great deal also. I use the Cardas Quad as it has such a low melting point. You can move quickly from point to point and don't need to spend to much time heating one joint.


----------



## ecclesand

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_I currently have both LME49722MA and LT1678CS8#PBF here but only one pair of SOIC to DIP adapters. So I'm asking you guys for advice. Which should I go for first with testing in my Essence STX? I'll eventually order some more Brown Dogs though._

 

I don't have the LME49722MA, but I did mount the LT1678CS8 on a BD adapter already. It's a decent opamp reminiscent of the LT1358. I may need to give it another listen as I have been modding headphones like crazy lately. From my perspective, I would recommend you mount the LME49722MA and report back since I haven't heard that one yet.


----------



## Cynips

LME49722MA it is then


----------



## Gamerphile

I'm piecing something together with a few work buddies ala CMoy with USB and DAC and find the LME49722MA interesting - hope you like 'course right now it looks as my number one from a spec' point of view. BTW we ARE doing a 8-pin socket just for security and the run of rolling 
	

	
	
		
		

		
		
	


	




 ...thought some of the guys are not from R'n'D so we might have to teach them about all the tech stuff - they mainly got in because being a audio company its just silly to spend hundred of USD on a system if we can have fun making our own...

 Thanks for all the inputs here!


----------



## ROBSCIX

I just got finished building two dual 1611 modules. I have only tested in buffer postion so far but they sound not too bad. They are new though as the solder cooled and I popped them in the circuit for testing. I wil have to spend more time with them before I make up my mind.

 Back to soldering...


----------



## crapback

I just wanted to post some pics of my zero with 3 earth hdams inside. It's a bit of a pain in the butt to get them in. I ended up cobbing up some insulating material by scavenging a weller desoldering pump package. I am a bit worried about noise issues from having the one hdam so close to the transformer but I can't hear any difference in the channels so far so hopefully that won't be an issue. 

 What stinks is I've only had about 10 minutes to listen to them because of my work schedule and my sister's wedding this weekend. To make things worse my hp out jack on my predator isn't working and needs to be sent back to ray for service. I'll have to see if my nuforce is acting up or i'm having a usb issue with my EeePC. I have 3 more hours here in the back of the car on the way to rhode island to test it out. It's not that easy typing while my sister's driving.


----------



## ROBSCIX

It may be a concern maybe some better sheilding would help such as some ERS paper.


----------



## ecclesand

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I just wanted to post some pics of my zero with 3 earth hdams inside. It's a bit of a pain in the butt to get them in. I ended up cobbing up some insulating material by scavenging a weller desoldering pump package. I am a bit worried about noise issues from having the one hdam so close to the transformer but I can't hear any difference in the channels so far so hopefully that won't be an issue. 

 What stinks is I've only had about 10 minutes to listen to them because of my work schedule and my sister's wedding this weekend. To make things worse my hp out jack on my predator isn't working and needs to be sent back to ray for service. I'll have to see if my nuforce is acting up or i'm having a usb issue with my EeePC. I have 3 more hours here in the back of the car on the way to rhode island to test it out. It's not that easy typing while my sister's driving. 
	

	
	
		
		

		
		
	


	


_

 

Good luck with the HDAMs. Initially, I was impressed with all of them in my Compass and preferred the SUN for it's aggressive nature. However, after rolling other opamps in my bagged/repaired Compass and Peridot DAC, my attitude toward them has changed somewhat. IMHO, the LT1057, LT1358 and the LM49720HA are much better sounding than any of the HDAMs. Of course, that is my opinion and ymmv.


----------



## leeperry

yeah, I've come to the conclusion that these Audio-GD parts are not really worth the trouble...you'd better go Burson or nothing, but then you need to add caps and sockets. at least the Audio-GD's are PNP.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Good luck with the HDAMs. Initially, I was impressed with all of them in my Compass and preferred the SUN for it's aggressive nature. However, after rolling other opamps in my bagged/repaired Compass and Peridot DAC, my attitude toward them has changed somewhat. IMHO, the LT1057, LT1358 and the LM49720HA are much better sounding than any of the HDAMs. Of course, that is my opinion and ymmv._

 

I find the existing HDAM modules have a very different signature then alot of opamps. I think it depends a great deal on the circuitry,what type of signature your personally like and of course your speaker/phones. 
 I know quite a few guys that use HDAMS and love them and they have tested many opamps for comparison. On the flip side I know guys that prefer the chip opamps. Personally, I like to use a combination of both for certain circuits.
 only HDAMS for some and only chips for others. Whatever gives me the sound I am looking for.


----------



## crapback

I like the brief first impressions that I got but I won't get a chance to do any serious listening until sunday. It's gonna be tough to tear me away from the 797/1361 combo that's my favorite so far. I think my expectations were a little high from everything I've read about the hdams. They definitely weren't as drastic a difference from the chips as I thought they were going to be. What surprises me most from the short time running them is how warm they get. They didn't get hot, just nice and toasty warm so they give off that nice circuity smell.


----------



## murrays

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I just wanted to post some pics of my zero with 3 earth hdams inside. It's a bit of a pain in the butt to get them in. I ended up cobbing up some insulating material by scavenging a weller desoldering pump package. I am a bit worried about noise issues from having the one hdam so close to the transformer but I can't hear any difference in the channels so far so hopefully that won't be an issue._

 

Personally, I'd be concerned about the long wire extensions from the DIP sockets. That's likely to be a breeding ground for all sorts of stability issues and noise pickup. How do you manage to bypass the power connections on that arrangement? Ideally you want the bypass capacitors to have very short connections between power pin and the correct ground point. Do the modules have built-in power supply bypassing?


----------



## crapback

I was a bit worried about EMI/RFI issues with the long leads but I can turn the volume all the way up with winamp/medimonkey/foobar paused and there is just a slightly audible bit of hiss that is even in both channels. I thought there might be a bit of hum from the transformer's magnetic field but there was no hum at all. I would love to be able to come up with a better arrangement than the use of the long extension leads but I drive a truck for a living and for me to be able to bring my zero with me I need to be able to keep it closed up. If I could leave the top of all the time i'd probably just stack a couple dip sockets till the hdams could clear the caps on the HA.

 I'm a bit of a noob in electronics so i'm not quite sure what you are talking about bypassing. All I know is there are a pair of bypass caps on each module and I have bypass caps on all the electrolytic caps of the frankenzero mod plus a few. Are you saying that the length of the leads is decreasing the effectiveness of the bypass caps on the modules? This is all a fun learning experience for me so all advice is appreciated.


----------



## crying

*


----------



## crying

Yes I loved the LT1028, but with all this talk about the LT1057 I wanted to hear it again...

 So I put it in, and at a first impression (after some time) it sounds very good. Like the expressive flowing mids, etc.

 It certainly has a different and probably more lifelike tonality than the OPA827.


 Compared to the LT1122, which is FET like the OPA827 and LT1057, I wouldn't say the LT1057 sounds better... But it sounds similar. I think that the LT1122 (pins 7-8 of each LT1122 connected together, see datasheet) has more detail resolution, thanks to its greater speed. On the other hand, the LT1057 has a very lovely tonality.


----------



## crying

Someone asked for a single version of the LT1057... well, that's easy. LT1056 (better) or LT1055.


----------



## Currawong

I've decided the nicest mids I've heard with an opamp goes to the OP27G I have here (I might have read that G wrong, but I don't think so). Anyway, I can't find info on the "G" anywhere, so I'm wondering if there is a dual opamp that has equally epic mids. The 627 is too warm and its trebble too rolled-off, by the way.


----------



## leeperry

hummm, be careful w/ those expensive op-amps through TI....fed-ex is asking me for custom taxes now 
	

	
	
		
		

		
		
	


	




 I hate private couriers..I'm gonna cancel the OPA827AID.


----------



## crying

Hmm, nice, but the LT1028CS8 sounds better than the LT1057ACN8 for sure (as expected).

 My choice for the definitive opamp seems to be among LT1028 and OPA1611 ... unless I rediscover the LT1677 once again, LOL


----------



## ROBSCIX

I built a couple dual 1611 modules yesterday and they are quite good so far based on testing. I also built a few new OPA211's and I have been testing those in a new circuit in the buffer position and getting great gains from this match.


----------



## crying

If you want to use them as headphone drivers, the OPA1611/12 are much better than the OPA211/2211 since they have almost twice the output current.


 I want browndogs!


----------



## SpudHarris

I'm gonna sound like a real noob here but what the heck....... In my P3 and P3+ I have L/R sockets + Buffer sockets + Ground/VGround sockets. I only use the Buffers that came with or my Hi-C or Stacked that I adapted myself, are you saying I can use standard opamps for buffer positions?


----------



## crying

It could be. Depends on how the buffer socket's connections are arranged.

 To use a (single) opamp as a buffer you must configure it as a unity gain follower, by either linking its pins 2 and 6 together or bridging them with a resistor, say 1K ohm. Maybe this is already done by the P3's circuit (a proper buffer like the BUF634 would not use pin 2 of the socket so it would not do harm). Maybe not. You would have to try...


 That said, I can't see why you'd want to use an opamp as a buffer, rather than a BUF634 or something (say LMH6321).


----------



## ROBSCIX

Quote:


  Originally Posted by *crying* /img/forum/go_quote.gif 
_If you want to use them as headphone drivers, the OPA1611/12 are much better than the OPA211/2211 since they have almost twice the output current.


 I want browndogs!_

 

No, this is a line out buffer.
 Yes, you need adapters as most of the best audio aopmps that I have tried are single channel, SOIC or both. Not to mention TO-99 packages..


----------



## LuciferX

My samples for Linear never comes, im from Argentina. TI and NS send me all for free and fast. Is this normal? (I've ordered LT1057ACN8 and LT1355CN8)


----------



## leeperry

my LT1057ACN8 never came either...I think they don't have them in stock or sumthing, as my LT1677/78 came very quickly several weeks later


----------



## wsatia

How do you guys find the AD845's? I kinda like them in the P3 with certain headphones. And thanks SpudHarris and ROBSCIX for the help! I'll be checking out my options and reporting back when I've gotten new opamps/buffers. Just wish I had someway to get my hands on the Hi-C 634's. But even normal BUF634's would be better than the bypassed buffers or stock buffers for the P3 right?


----------



## murrays

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I was a bit worried about EMI/RFI issues with the long leads but I can turn the volume all the way up with winamp/medimonkey/foobar paused and there is just a slightly audible bit of hiss that is even in both channels._

 

You say you are getting background hiss and the modules are running warm/hot - these are 2 symptoms of HF oscillation. Sometimes the audio will sound OK as 'phones and ears can only process the lower audio frequencies. However, the amps could be oscillating in the MHz range, effectively creating an AM radio broadcast. This can use up a lot of power (hence the heat) and can go as far as destroying components.
 At the higher frequencies (MHz) those long leads provide all sorts of unwanted couplings between inputs, outputs, feedback loop, power, etc that can provoke oscillation.

 One thing that may be saving your bacon, and someone else who knows better may be able to step in here to confirm/deny 
	

	
	
		
		

		
			





, your modules may be tailored to only work at audio frequencies and may be deliberately rolled off below the HF range. Certainly most chip op amps will have a usable bandwith up to at least 1 Mhz or beyond. I have personally seen such chips oscillating continuously while still providing audio output. Presumably an AM transistor radio would pick up signals in the MW band?

  Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_ I thought there might be a bit of hum from the transformer's magnetic field but there was no hum at all. I would love to be able to come up with a better arrangement than the use of the long extension leads but I drive a truck for a living and for me to be able to bring my zero with me I need to be able to keep it closed up. If I could leave the top of all the time i'd probably just stack a couple dip sockets till the hdams could clear the caps on the HA.

 I'm a bit of a noob in electronics so i'm not quite sure what you are talking about bypassing. All I know is there are a pair of bypass caps on each module and I have bypass caps on all the electrolytic caps of the frankenzero mod plus a few. Are you saying that the length of the leads is decreasing the effectiveness of the bypass caps on the modules? This is all a fun learning experience for me so all advice is appreciated. 
	

	
	
		
		

		
		
	


	


_

 

Yes, bypassing requires very short leads to eliminate inductance and self-resonances in the HF ranges. It is good that there are caps on the modules, as well as the ones on the main board. A short, direct earth return is a requirement in many cases, though. These modules may be different enough from chip op amps that what you are doing is OK, whereas it wouldn't be with a standard chip op amp on the end of such long extensions. I will admit to having no experience with those discrete modules - others may be able to fill in the details here...


----------



## crying

Quote:


  Originally Posted by *wsatia* /img/forum/go_quote.gif 
_How do you guys find the AD845's? I kinda like them in the P3 with certain headphones. And thanks SpudHarris and ROBSCIX for the help! I'll be checking out my options and reporting back when I've gotten new opamps/buffers. Just wish I had someway to get my hands on the Hi-C 634's. But even normal BUF634's would be better than the bypassed buffers or stock buffers for the P3 right?_

 

The AD845KN is a quite good sounding opamp, IMO. It's natural and colorful...

 Too bad it doesn't come SMD and doesn't like too low supply voltages.


 BTW, the LT1057 is nice but overrated. Take the LT1678 or the LT1122 instead (the latter is single, and FET input like the LT1057, but faster, better and newer). Or take the LT1364.


----------



## crying

Quote:


  Originally Posted by *wsatia* /img/forum/go_quote.gif 
_But even normal BUF634's would be better than the bypassed buffers or stock buffers for the P3 right?_

 

The BUF634 is a very nice buffer, but it depends on how you set its bias... with the lowest bias it sounds rather coarse, while if you put a 220 ohm (or lower) resistor between pins 1 and 4 it sounds much better...

 That said, I have no idea how the discrete little buffer (two transistors?) supplied with the P3 should sound...


----------



## wsatia

Quote:


  Originally Posted by *crying* /img/forum/go_quote.gif 
_The AD845KN is a quite good sounding opamp, IMO. It's natural and colorful...

 Too bad it doesn't come SMD and doesn't like too low supply voltages.


 BTW, the LT1057 is nice but overrated. Take the LT1678 or the LT1122 instead (the latter is single, and FET input like the LT1057, but faster, better and newer). Or take the LT1364._

 

 Quote:


  Originally Posted by *crying* /img/forum/go_quote.gif 
_The BUF634 is a very nice buffer, but it depends on how you set its bias... with the lowest bias it sounds rather coarse, while if you put a 220 ohm (or lower) resistor between pins 1 and 4 it sounds much better...

 That said, I have no idea how the discrete little buffer (two transistors?) supplied with the P3 should sound..._

 

Pardon my ignorance but what's FET input? And what other kinds of input are there? And hmm I'll check those out.

 Anyway I was wondering what the two types of slots for opamps actually do in the P3? Does anyone know? I think the L/R slots work like normal but what do the 3/4 slots (as called in the manual) actually do? Does anyone know?

 And I guess I'll have to find someone to help me do up the resistor on the 634.


----------



## SpudHarris

wsatia, the resistor between pins 1 & 4 on a Buf634 is ''Hi-C'' and sounds considerably better than the standard 634's and also the ibasso transister buffers. That said, I prefered the ibassos over the standard 634's.

 I make the Hi-C adapters on DIP sockets (I'll post a pic later) so the 634's can be used as standard in other applications if need be.

 The 3/4 slots in your P3 are ''Ground channel'' and you can only use single opamps here, also both sockets need to be occupied giving 4 channels. With the P3+ you can bypass one if you like to give 3 channels.

 Regards

 Nigel


----------



## wsatia

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_wsatia, the resistor between pins 1 & 4 on a Buf634 is ''Hi-C'' and sounds considerably better than the standard 634's and also the ibasso transister buffers. That said, I prefered the ibassos over the standard 634's.

 I make the Hi-C adapters on DIP sockets (I'll post a pic later) so the 634's can be used as standard in other applications if need be.

 The 3/4 slots in your P3 are ''Ground channel'' and *you can only use single opamps here*, also both sockets need to be occupied giving 4 channels. With the P3+ you can bypass one if you like to give 3 channels.

 Regards

 Nigel_

 

Damn I had no idea I could only use single opamps in the Ground channel sockets. I've always used dual opamps in them 
	

	
	
		
		

		
		
	


	




 Hmm okay a picture would be good so I can show someone who can solder/do it up for me 
	

	
	
		
		

		
		
	


	




 Oh and when should I use the bypassed buffers and when should I use a dedicated buffer? Is there any requirements or something or is it just based on what sounds better?


----------



## SpudHarris

There are a few that people will recommend such as the AD8397 but I think what ever sounds good.

 Here are Hi-C adapters I made for use with the Buf634's. Do you have any 634's yet?


----------



## wsatia

Nope no 634's yet but I can get them from my local Farnell anytime.


----------



## SpudHarris

Get them and PM me your address and I'll post you a couple of adapters......


----------



## SpudHarris

Quote:


  Originally Posted by *wsatia* /img/forum/go_quote.gif 
_Damn I had no idea I could only use single opamps in the Ground channel sockets._

 

My bad, sorry been such a long time since I rolled with the P3 
	

	
	
		
		

		
		
	


	




....You can use duals in the centre configuration, it was obviously the buffer positions I was thinking of. I usually use singles in L/R & G because I use Class A adapters to squeeze a little more from them which you can't do with duals.


----------



## ROBSCIX

@Spudharris:
 Can you elaborate why you cannot use a similar idea with a dual channel module? 

 I am just curious though, I like your adapter and idea.


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_my LT1057ACN8 never came either...I think they don't have them in stock or sumthing, as my LT1677/78 came very quickly several weeks later 
	

	
	
		
		

		
		
	


	


_

 

They have them in stock. I just bought 3 of them and got them in 3 days. And yes, I did say bought. Perhaps they're not sending any out as samples anymore.


----------



## SpudHarris

I just ''Bought'' one also from Farnell. Should be here tomorrow and I will see if there is a successor to the AD797's....


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_There are a few that people will recommend such as the AD8397 but I think what ever sounds good.

 Here are Hi-C adapters I made for use with the Buf634's. Do you have any 634's yet?




_

 

Hey Nigel...
 What resistor are you using for your adapter? Also, can you tell me what pins it should be soldered to?

 EDIT: DOH! I should have read your earlier post. Never mind.


----------



## crapback

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_You say you are getting background hiss and the modules are running warm/hot - these are 2 symptoms of HF oscillation. Sometimes the audio will sound OK as 'phones and ears can only process the lower audio frequencies. However, the amps could be oscillating in the MHz range, effectively creating an AM radio broadcast. This can use up a lot of power (hence the heat) and can go as far as destroying components.
 At the higher frequencies (MHz) those long leads provide all sorts of unwanted couplings between inputs, outputs, feedback loop, power, etc that can provoke oscillation.

 One thing that may be saving your bacon, and someone else who knows better may be able to step in here to confirm/deny 
	

	
	
		
		

		
		
	


	




, your modules may be tailored to only work at audio frequencies and may be deliberately rolled off below the HF range. Certainly most chip op amps will have a usable bandwith up to at least 1 Mhz or beyond. I have personally seen such chips oscillating continuously while still providing audio output. Presumably an AM transistor radio would pick up signals in the MW band?



 Yes, bypassing requires very short leads to eliminate inductance and self-resonances in the HF ranges. It is good that there are caps on the modules, as well as the ones on the main board. A short, direct earth return is a requirement in many cases, though. These modules may be different enough from chip op amps that what you are doing is OK, whereas it wouldn't be with a standard chip op amp on the end of such long extensions. I will admit to having no experience with those discrete modules - others may be able to fill in the details here..._

 

The hiss is much less than the stock zero. At normal listening level with no signal there is no noise at all. It isn't until the volume is at about it's last 10% or so to max level that there is any audible hiss. With my lowest gain music in my library, I can't turn the volume past the 10 o'clock position without it starting to hurt my ears.

 As far as the heat generated by the hdams, I wouldn't say they are any warmer than the stock opamps get. I believe that there were actually changes made to the board design of the zero to accomodate the ground wire for the hdams. I can't remember which thread I read that in though. I've tried removing the extension wire for the dac hdam to see if it generated less heat but I couldn't tell any difference other than it's still much cooler than the mosfet heatsinks. I tried not attaching the ground wire like in the zero intro thread and they seemed to get a little less warm, but they didn't sound right. In all honesty, I've had a bit of a heat paranoia with electronics since my athlon 1700 overclocking days so I will email kingwa to ask him if they should be getting warm.

 As for the sound I think they work great in the zero's el cheapo circuit. They may not be much of an improvement or even a step down in better gear, but I like them so far and will be enjoying my little mutant until my bank account recovers from my sister's wedding this weekend. 
	

	
	
		
		

		
		
	


	




 There has to be some kind of topical cream for upgraditis, right? 
	

	
	
		
		

		
		
	


	





 I recieved an answer to my email to Kingwa:

 Date: Mon, 14 Sep 2009 09:19:18 +0800
 From: audio-gd@126.com
 To: that really awesome guy that all the women love@hotmail.com
 Subject: Re:

 Dear Sir,
 The OPA are work on class A, power supply is more than normal chips (like OPA2604) 5X times, so it get warm, around 45C, this is very safe .
 The OPA don't roll off at 20KHz, it depend on the outside circuits design, like the ZERO, its analogy filter is apply -12DB roll off design, so maybe let 20KHz roll off around 1DB to 4DB, even you apply OPA2604.
 Kingwa


 在2009-09-14，"og og" <and wears underoos cause he's a real superhero, not just cause they look awesome@hotmail.com> 写道：

 Hello again Kingwa,

 I recently ordered a number of your opa's and I have a question about them. I have an '09 tianyun zero with 3 opa earths in it. Are the opa's supposed to get warm? If they are, about how warm should they get? compared to say, the mosfet heatsinks? Also, is there a high frequency rolloff with the opa's to prevent any issues with oscillation affecting their performance?

 Thanks again, Joel


----------



## wsatia

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_My bad, sorry been such a long time since I rolled with the P3 
	

	
	
		
		

		
			





....You can use duals in the centre configuration, it was obviously the buffer positions I was thinking of. I usually use singles in L/R & G because I use Class A adapters to squeeze a little more from them which you can't do with duals._

 

Ahh what does a class A adapter actually do? I've heard some biased output or something does that have to do with class A opamps?


----------



## SpudHarris

Yeah, by shorting pins 6 and 7 with a resistor you bias to Class A. It's subtle but there are improvements if you have the right gear to reproduce them i.e. good cables, source, phones. Any improvement is a plus and when you get to a certain point even small ones are so worth it.


----------



## crapback

Does biasing a chip opamp to class A make it use much more power and generate much more heat? or is that just with discrete class A?


----------



## SpudHarris

I haven't noticed any increase in heat.


----------



## leeperry

hah, the low end bass on the 49722MA still sucks, just like on the 49720NA...waste of time 
	

	
	
		
		

		
		
	


	




 I will try the THS4032 now, and the OPA211 later on


----------



## chesterqw

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Yeah, by shorting pins 6 and 7 with a resistor you bias to Class A. It's subtle but there are improvements if you have the right gear to reproduce them i.e. good cables, source, phones. Any improvement is a plus and when you get to a certain point even small ones are so worth it._

 

what resistor value should be used?


----------



## leeperry

so what do you guys think of the JRC4580 anyway? maybe it's time for me to change my mind 
	

	
	
		
		

		
		
	


	




 that's the JRC4580, 0.0005% THD+N :




 LME49720, THD+N rate of 0.00003% :




 so yes, it's more distorted! but the LME49720 is nowhere near as beefy to drive headphones?! and to amplify a signal for headphones....you have to distort it anyway 
	

	
	
		
		

		
		
	


	




 I was pretty surprised by how distorted an Aria Arietta sounds...yikes, hated it! and most ppl swear by it 
	

	
	
		
		

		
		
	


	




 the line-out on the ST/STX seems to offer enough gain to drive headphones, but it's clearly not the case on the HD2...yet its HP out seems to sound better than the ST/STX HP out anyway, that had a very shrill upper spectrum to me(and to another friend too, using a dx1k).

 I guess aiming at very low THD is nice and all...but someone's gotta feed the phones 
	

	
	
		
		

		
		
	


	




 I was about to roll the THS4032 on the line-out, but I'll keep the 3xLME49722 + JRC4580 on the HP out a bit I think...the sound is more distorted on HP out but my cd1k(same drivers as cd3k) is pretty bass shy, it takes power to make the low end sing I'm afraid


----------



## SpudHarris

Quote:


  Originally Posted by *chesterqw* /img/forum/go_quote.gif 
_what resistor value should be used?_

 

2.2k


----------



## 12Bass

JRC4580 has higher output current, which makes it better for driving a load. AD8397 is one of the better chips for driving a headphone directly, far superior to JRC4580, IMO.


----------



## leeperry

oh ok, but it's soldered and it's not even SOIC8..so I'd rather not touch it 
	

	
	
		
		

		
		
	


	




 anyway, it seems to add an "analog" touch that's a nice contrast w/ the LME49722 clinical sound I think...something my previous soundcards were lacking, the mids are a lot less fatiguing on this card anyway(even on the line-out).

 and I wonder if I could try the 3<>5 bypass trick in the AK4396 buffer op-amps now that I use the JRC4580 on the HP out 
	

	
	
		
		

		
		
	


	




 when I've first put the LME49722...they were crackling a bit, but they have stopped now?! I'll try the THS4032 tomorrow, and the OPA211 later on


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I haven't noticed any increase in heat._

 

You stated your bias resistor will only work with a single channel. Is there asimilar modification for a dual channel opamp?
 If not, maybe I will build a dual DIP8 adapter for two single channels biased to Class A. You have me curious to check this out a bit further..


----------



## leeperry

humm, I had forgotten about these 2 links I had been given on a french forum ages ago:

Google Translate

Opamp Design

_NJM4580, distortion rate 0.00040% (-108dB)_...he's not such a bad guy after all 
	

	
	
		
		

		
		
	


	




 plenty beefy to drive headphones, and a nice contrast w/ the AK4396+2*LME49722! it gives that "tuby" sound ppl always talk about, a complete opposite of the ear-splitting sound of some other soundcards I used to own in the past. human ears were not meant to listen to raw sinewaves 
	

	
	
		
		

		
		
	


	




 I can't believe how bassy it makes my cd1k, yet very detailed...just not harsh AT ALL 
	

	
	
		
		

		
		
	


	




_The Stranglers - Golden Brown_ is a perfect example, PRAT is high yet the harpsichord doesn't sound uber-bright whatsoever.


----------



## leeperry

TO99 on adapters...ghetto style 
	

	
	
		
		

		
		
	


	




http://www.pcdvd.com.tw/showthread.p...9&page=2&pp=10

 damn, I hardly ever listen to rock....but the 4580 was born to play this type of music, the RocknRolla OST is mind blowing 
	

	
	
		
		

		
		
	


	




 I guess there's a reason -after all- why RME puts it in a lot of their cards: RME User Forum / Which output Opamps are used on Fireface 400?

 luckily the AK4396 doesn't have any I/V, and many op-amps seem to behave better as buffers than I/V..


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_You stated your bias resistor will only work with a single channel. Is there asimilar modification for a dual channel opamp?
 If not, maybe I will build a dual DIP8 adapter for two single channels biased to Class A. You have me curious to check this out a bit further.._

 

According to ''HiFlight'' (My OpAmp Guru) this can't be acheived. He's the guy who let me into this little secret + OBCA (Output Bypassed Class A) which will only work with AD744's plus one other OpAmp (NE5534 I think).

 This is Class A Only Adapter.







 This is OBCA (Output Bypassed Class A) AD744's


----------



## shrisha

Very helpful thread, Thank you for everybody.
 Being inspired about opamp rolling I requested LT website for a samples. And now they asking me for some questions. I honestly don't know what should I answer to then. 
	

	
	
		
		

		
		
	


	




 Here is questions:
 Thank you considering Linear Technology Products in your design.

 We request you to provide us the following details

 Project name - 
 Application – 
 Brief program Description –
 Part Number/s- 
 Quantity/Board-
 Prototype Date/ Proto Qty - 
 Annual Qty - 
 Mass production date - 
 Production Location -
 End Customer name - If it is available.
 Design Location with complete Address - 
 Design Engineer Name & contact Details - 

 Could someone help me please, coz my own imagination wouldn't enough to answer it. Any though will really appreciate. 
 Thanks.


----------



## leeperry

be imaginative 
	

	
	
		
		

		
			





 besides they've never asked me any of these..


----------



## shrisha

Good for you. Bad for me 
	

	
	
		
		

		
		
	


	




 Not only imagination but knowledge about this stuff. I'm total noob on electronic field.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_According to ''HiFlight'' (My OpAmp Guru) this can't be acheived. He's the guy who let me into this little secret + OBCA (Output Bypassed Class A) which will only work with AD744's plus one other OpAmp (NE5534 I think)._

 

The biasing only works with the AD744/NE5534 or the OBCA only works with these opamps?
 I have never seen the OBCA idea, can you explain what is going on with that unit? -Very interesting BTW.

 I appreciate your help and information.


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_
 The biasing only works with the AD744/NE5534 or the OBCA only works with these opamps?
 I have never seen the OBCA idea, can you explain what is going on with that unit? -Very interesting BTW.

 I appreciate your help and information._

 

OBCA Only works with AD744's and NE5534's. The Class A Mod (2.2k Resistor between pins 6-7) works with any single OpAmp. Don't be fooled by my use of such mods as I'm not a techie by any stretch of the imagination, I just learned a lot from HiFlight (Ron Kerlin) on the P3 and P3+ threads that ran a while back.

 When you get to a certain point in this hobby the cost of even small improvements in SQ can be disproportionate. The beauty of these mods is they are are cheap and if like most of us you have a critical ear they are so worth it. A little more body, depth and air for a few pence - bargain in my books.


----------



## murrays

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_OBCA Only works with AD744's and NE5534's. The Class A Mod (2.2k Resistor between pins 6-7) works with any single OpAmp._

 

The "class A mod' can be adapted to work with dual op amps as well, as it is just a resistor (or Constant Current Source) from the output pin to either +V or -V supply pin. The pins are in different places for dual chips, and there's less physical space to fit the mods if you want to do it right on the chip/socket.

 Remember, pretty much all of these op amps have a certain level of so-called "Class A' bias on their output stage by design. Check out the data sheet "quiescent/idle current" - typically 5 to 10 mA. This is fine for a buffered output into several K-ohms. I think Tangent's website has discussion of the higher biasing requirements for directly driving headphones.

 Heh, my original LM1875 based headphone amp (from 1996) has about 70mA of standing bias - plenty for class A into headphones!


----------



## majkel

The only op-amp I know that improved from the class A biasing was OP27G. All modern op-amps are optimized to work without such tricks and the sound always gets worse. Sometimes there is a flaw in the signal chain which gives impression of improvement, kind of sweeter sound, but their virtual presence and spatial order gets worse. Some of the op-amps sound thin when biased this way, like LME49713.


----------



## majkel

I stopped using dual op-amps for multi-channel purposes. The crasstalk effects are too obvious for me since my amp and DAC use separate circuits for each channel. I am waiting for my samples from LT and I ordered some LME49710HA from Farnell. Should arrive tomorrow.


----------



## murrays

A quick question for those in the know - are dual op amps fabricated on one single wafer of silicon? If they are, then even if no circuitry is shared they will still be sharing the same substrate as well as their supply pins.


----------



## majkel

Yes, they are, and when you refer to the transistor count, it is not twice the single op-amp amount but less which means some circuits, most probably current mirror references, are common.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_OBCA Only works with AD744's and NE5534's. The Class A Mod (2.2k Resistor between pins 6-7) works with any single OpAmp. Don't be fooled by my use of such mods as I'm not a techie by any stretch of the imagination, I just learned a lot from HiFlight (Ron Kerlin) on the P3 and P3+ threads that ran a while back.

 When you get to a certain point in this hobby the cost of even small improvements in SQ can be disproportionate. The beauty of these mods is they are are cheap and if like most of us you have a critical ear they are so worth it. A little more body, depth and air for a few pence - bargain in my books. 
	

	
	
		
		

		
		
	


	


_

 

Thx for the information. I appreciate it.
 I consider my ear to be critical as I notice small changes in sonic signature.
 I am always looking for upgrades even if they are smaller then others.
 can you explain the point of the OBCA mods? -I am unsure what the point is of bypassing the output?


----------



## ecclesand

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_The "class A mod' can be adapted to work with dual op amps as well, as it is just a resistor (or Constant Current Source) from the output pin to either +V or -V supply pin. The pins are in different places for dual chips, and there's less physical space to fit the mods if you want to do it right on the chip/socket.

 Remember, pretty much all of these op amps have a certain level of so-called "Class A' bias on their output stage by design. Check out the data sheet "quiescent/idle current" - typically 5 to 10 mA. This is fine for a buffered output into several K-ohms. I think Tangent's website has discussion of the higher biasing requirements for directly driving headphones.

 Heh, my original LM1875 based headphone amp (from 1996) has about 70mA of standing bias - plenty for class A into headphones! 
	

	
	
		
		

		
		
	


	


_

 

Interesting. So for a dual opamp...since there are two outputs, would you need 2 resistors...one from the +V to output A and one from the +V to output B? Or could you use one resistor and pigtail one end of it to both the A and B output?


----------



## leeperry

humm indeed, the THS4032 seems to sound seriously good to me! I will try the THS4031 later on...but my soundcard layout uses one dual op-amp per channel(AK4396), so it's not quite shared...

 trebles are less muffled than the LME49722, but the SS is nowhere near as impressive...time to try the 49720HA again


----------



## crapback

For class A goodness I think i'll stick to my new hdams in my zero. 
	

	
	
		
		

		
		
	


	




 I like the earth in the dac better than the 797brz. The detail and imaging are great and the dynamics are so much better than the chip. I'm trying to think of a better way to describe the differences and I don't want to call the 7979b lifeless cause it is definitely not lifeless. I guess I have to say that the opa earth can be both in your face and laid back and everything in between while the 797brz just seems to sit more in the middle. 

 I have a compass on order that should be here within the next 2 weeks so I'll have a much better piece of equipment to test out some opamps in. For all I know, my opinions could be totally different with a different circuit.


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I stopped using dual op-amps for multi-channel purposes. The crasstalk effects are too obvious for me since my amp and DAC use separate circuits for each channel. I am waiting for my samples from LT and I ordered some LME49710HA from Farnell. Should arrive tomorrow._

 

I am with you. I used to use the LME49720HA but found that a dual LME49710HA seemed to sound better in my gear so I started using those instead. When talking with people I would consider opamp experts they always tend to agree with this idea also.


----------



## leeperry

so what did they do w/ Andrea? ban his whole ISP or ppl using his web browser version? 
	

	
	
		
		

		
		
	


	




 ok, well the LME49720HA bass...amplified by the JRC4580 is just


----------



## SpudHarris

Any of you guys have experience with the TLE2141?? I've ordered a couple from Farnell, they are ''Jelly Bean'' OpAmps (real cheap) but are raved about on the D10 OpAmp thread as the L/R of the new ''Top Kit'' again biased to Class A.


----------



## ROBSCIX

There are many jelly bean opamps that can give you good soudn in the right circuits.


----------



## leeperry

cheap generic op-amps seem to work really well as buffers, combined w/ killer op-amps set as LPF or I/V...they tend to give a tuby sound to kill the harshness(553x/4580) 
	

	
	
		
		

		
			





 and can you beat the LME49xxx soundstage anyway? it's so amazing on headphones


----------



## LuciferX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_cheap generic op-amps seem to work really well as buffers, combined w/ killer op-amps set as LPF or I/V...they tend to give a tuby sound to kill the harshness(553x/4580) 
	

	
	
		
		

		
		
	


	




 and can you beat the LME49xxx soundstage anyway? it's so amazing on headphones 
	

	
	
		
		

		
		
	


	


_

 

What do you think of this?:

 4580 (buffer) > OPA2132 (LPF or I/V)
 4580 (buffer) > LME49720NA (LPF or I/V)
 4580 (buffer) > LME49860NA (LPF or I/V)

 (My HT OMEGA Claro Halo has 4 x 4580 by default)


----------



## 12Bass

Generally speaking, I prefer using an AD8397 over an NJM4580 for driving headphones. I've found the 4580 to sound somewhat edgy and murky when compared with better op amps. The AD8397 can be a bit difficult to use in some circuits; however, it can provide six times the output current and sounds clearer and more punchy in the bass, IMO. I recently installed one in my RME Digi96/8 PST (with AD1852).


----------



## majkel

When I replaced NJM4580 for AD8022 as the output buffers in my CD player, overall sound resolution improved.


----------



## murrays

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Interesting. So for a dual opamp...since there are two outputs, would you need 2 resistors...one from the +V to output A and one from the +V to output B?_

 

Yes.

  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Or could you use one resistor and pigtail one end of it to both the A and B output?_

 

Definitely Not! This would short the two outputs together.


----------



## murrays

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_The biasing only works with the AD744/NE5534 or the OBCA only works with these opamps?
 I have never seen the OBCA idea, can you explain what is going on with that unit? -Very interesting BTW.

 I appreciate your help and information._

 

have a look at this article ...
http://waltjung.org/PDFs/ADI_1992_Seminar_Audio.pdf

 on this useful site ...
Services


----------



## leeperry

Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_What do you think of this?:

 4580 (buffer) > OPA2132 (LPF or I/V)
 4580 (buffer) > LME49720NA (LPF or I/V)
 4580 (buffer) > LME49860NA (LPF or I/V)

 (My HT OMEGA Claro Halo has 4 x 4580 by default)_

 

yeah, it looks like you'd need to change the two first op-amps that are used for polarity stuff(AK4396 design), and then the two that are used as buffer.

 I don't know how the HP amp goes into your soundcard design(it's prolly used as buffer, so only 2 op-amps are actually swappable for this output?), but the LME49720HA does wonders on my HD2(same DAC/caps as your card)....great bass response, very HQ mids and HUGE soundstage.

 the high gain JRC4580 buffer(I've left it on +70%, but there's also a switch for +200% 
	

	
	
		
		

		
		
	


	




) gives me a much better low end bass response and makes the sound very enjoyable as a whole on the HP out....I'd dare to talk about synergy w/ the 128X oversampling from the AK4396, plus the LME49720 serie is known to offer some very high class post-filtering behind DAC's.

 I know DAC's are not supposed to have a "sound", but I'm more keen on the AK4396 design/sound(mandatory 128X OS) than on the PCM1792....many op-amps lack in I/V I was told(the AK4396 doesn't need it), like the burson's for instance...and the default OS on the BB DAC's is 64X, some manufacturers(like Asus) don't bother forcing it to 128X...the AK4396 sure does miracles


----------



## ROBSCIX

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_have a look at this article ...
http://waltjung.org/PDFs/ADI_1992_Seminar_Audio.pdf

 on this useful site ...
Services_

 

Thank for the information.
 I will add it to my nightly reading list.
 There are some great documents out there, put out by the engineers
 at various companies. Books dealing with opamps design, implemention
 etc. Can always find something more to read. I just need to get myself a kindle 
 or other portable document reader so I can take my hobbies with me!


----------



## LuciferX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_yeah, it looks like you'd need to change the two first op-amps that are used for polarity stuff(AK4396 design), and then the two that are used as buffer.

 I don't know how the HP amp goes into your soundcard design(it's prolly used as buffer, so only 2 op-amps are actually swappable for this output?), but the LME49720HA does wonders on my HD2(same DAC/caps as your card)....great bass response, very HQ mids and HUGE soundstage.

 the high gain JRC4580 buffer(I've left it on +70%, but there's also a switch for +200% 
	

	
	
		
		

		
		
	


	




) gives me a much better low end bass response and makes the sound very enjoyable as a whole on the HP out....I'd dare to talk about synergy w/ the 128X oversampling from the AK4396, plus the LME49720 serie is known to offer some very high class post-filtering behind DAC's.

 I know DAC's are not supposed to have a "sound", but I'm more keen on the AK4396 design/sound(mandatory 128X OS) than on the PCM1792....many op-amps lack in I/V I was told(the AK4396 doesn't need it), like the burson's for instance...and the default OS on the BB DAC's is 64X, some manufacturers(like Asus) don't bother forcing it to 128X...the AK4396 sure does miracles 
	

	
	
		
		

		
		
	


	


_

 

The Claro Halo use this diagram:






 [size=xx-small]_The each polarity signal produced by AK4396 goes to 2 dual opamps (U8 for left, U10 for right) In those dual opamps, each opamp handles only one polarity, either positive signal or negative. Then both exclusively amplified positive and negative signals are re-assembled and goes to another opamps (U9 for left, U11 for right) for second amplification. In the second dual opamp, U9, The one opamp is for left headphone and the other is for left RCA output. In U11, one opamp is for right headphone and the other is for right RCA output.


 This design maximizes the feature of AK4396DAC and it also dramatically improves stereo-talk.

 It is recommended to swap all four opamps for your preferred analog sound
 color. Factory installed opamps are 4580 (JRC).

 If you choose to swap only two, they must be U8 & U10 ( They are marked on PCB of Claro halo)_[/size]


----------



## leeperry

well, get a bunch of free samples(including the 49720HA/OPA2132P/LT1057/etc)...and see how it goes.

 rolling op-amps is a trap, as none of these chips is perfect....only the burson's would be close to this apparently(as buffers, not I/V).

 if you roll too much, you'll be expecting the impossible....I'd love the tamed down trebles of the 49722MA, the crazy low end bass/huuuuge soundstage of the 49720HA, and the super grainy mids of the OPA2132P. needless to say, this is not going to happen 
	

	
	
		
		

		
		
	


	




 the 49720HA is very easy to roll in the crappy STX pressed DIP8 sockets, but in proper machined sockets(where contacts are much tighter)...it's a major PITA: 



 so that's good! they'll stay there for a while...they're not perfect as the trebles are quite whiny(I have to EQ down my ear resonances anyway), but the bass/soundstage/mids are as good as it gets....the tuby high gain JRC4580 on top gives a very enjoyable SQ on HP, much higher than anything I had ever heard coming out of those Asus Xonar things....it sounds super-HQ HiFi, not digital harsh


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_rolling op-amps is a trap, as none of these chips is perfect....only the burson's would be close to this apparently(as buffers, not I/V).

 if you roll too much, you'll be expecting the impossible..._

 

Looking at the fact that you are putting them into a board that plugs into a PC, I would say that the op amps would be the least of the problem. A lot of electrical and RF interference may be polluting the power supplies. This may be why the metal can chips give you a noticeable difference? A lot of the difference you hear may not be the op amps per se, but the different types of noise fed into their power pins, and how they deal with it. It is always best to have clean power supplies - a difficult task in a PC environment. Have you considered/tried improving the capacitors on your board?


----------



## leeperry

indeed, a PC is a less than ideal environment...I had some EMI problems, but I appear to have fixed them all?! anyway, maybe I'll get one of these gigabyte mobo w/ 2oz of copper...I was told that they are fantastic for audio systems 
	

	
	
		
		

		
		
	


	




 whatever now w/ the HD2 or back then w/ the Asus Xonar's, I've never had anything polluting the audio...in a very audible way, that is.

 I understand an external stabilized PSU would help, but quite honestly many external DAC/HP amp run from a wallwart...that is even worse than a quality PC ATX PSU? a proper design is supposed to really clean the incoming current?

 I run a "deluxe" edition(released 1 year ago) of that HD2 board, w/ supposedly improved caps: 









 the sound sure sounds cleaner to me than on the Xonar..especially the stereo seperation, which doesn't appear "messy"...the bass is far better controlled, and the mids appear much more refined. I know I'll stay away from Nichicon caps in the future.

 but yes, the metal cap 49720 is a God bless for noisy environments!


----------



## ROBSCIX

Except you are jaming them loosley into the sockets and leaving the leads exposed.
 Weren't you complaining about oscialltion when you did this method on another card?
 I suggest you get some adapters and install them the right way.


----------



## leeperry

humm, strange...looks like this board needs to warm up to sound better? my 49720HA's are definitely burned in, but I was told that the board would take 10 days to sound its best(caps breaking in yada yada)...be it then, I never turn off my box anyway 
	

	
	
		
		

		
			





 anyway, the trebles seem to have got a tad darker, to the point that I don't need to EQ to kill ear resonances anymore...dark sources sure are great, one day I'll have to try a Chinese tube amp...just scared of my cat burning her nose on the tubes


----------



## Apocalypsee

I build my own analog out for my X-Fi Elite Pro so its easier for me to roll opamp 
	

	
	
		
		

		
		
	


	



 Because new Prodigy HD2 uses OS-CON on output decoupling caps, I gonna try it 
	

	
	
		
		

		
		
	


	




http://forum.lowyat.net/index.php?ac...ost&id=1196380

 Currently its powered by 350W PC PSU with better caps (12V), I'll build linear PSU soon

 Opamp that I've tried on it is Ti NE5534, LT1677 and LT1363, my current favorite is LT1363, the LT1677 is too forward and bright, while the NE5534 is very loose bass and not much detail on the high. Ordered LT1028 and soon maybe LME49710HA 
	

	
	
		
		

		
		
	


	




 Anymore opamp that can be used as active filters?


----------



## leeperry

wow, ghetto style to the bone...it lacks some brown packing tape to keep it together I think


----------



## ROBSCIX

Quote:


  Originally Posted by *Apocalypsee* /img/forum/go_quote.gif 
_I build my own analog out for my X-Fi Elite Pro so its easier for me to roll opamp 
	

	
	
		
		

		
		
	


	



 Because new Prodigy HD2 uses OS-CON on output decoupling caps, I gonna try it 
	

	
	
		
		

		
		
	


	




http://forum.lowyat.net/index.php?ac...ost&id=1196380

 Currently its powered by 350W PC PSU with better caps (12V), I'll build linear PSU soon

 Opamp that I've tried on it is Ti NE5534, LT1677 and LT1363, my current favorite is LT1363, the LT1677 is too forward and bright, while the NE5534 is very loose bass and not much detail on the high. Ordered LT1028 and soon maybe LME49710HA 
	

	
	
		
		

		
		
	


	




 Anymore opamp that can be used as active filters?_

 

There are two other members here using my dual LME49710HA modules. While they say they have a bit less mid bass then the LME49720HA, the have more low end extension and better sound staging.
 They sound quite good based on my tests and you have the room for them.


----------



## crapback

I never did get to test out the 1363's in my zero. I loved the 1361's in the amp but I only had a pair of mdip 1363's so I didn't bother to get any adapters. One of my other favorite LT opamps was the 1208 but that's a dual. I believe the lt1224 is a single channel version of it based on the data on the LT site. I preferred LT's high speed opamps before I picked up some opa earths from kingwa.
	

	
	
		
		

		
		
	


	




 Is it just me or do those 2 caps look like the tops are bulging a bit?


----------



## ROBSCIX

If you like the sound of the LT1208, perhaps make a adapters to go for a dual channel opamp to a single channel socket. Would't be too hard I think.
 I have dual single channel dip 8 to dual channly Dip 8 adapters. I am thinking I may have what you need to do this if your interested in trying it..let me look through my parts and get back to you.


----------



## crapback

Poop, thanks for the offer ROBSCIX. I should have quoted Apocalypsee. He said his current favorite were the 1363's so I was just trying to suggest something else in the LT high speed opamp flavor. That does make me wonder about how a dual opamp would sound adapted to operate as a single channel though. That is what you were talking about right?


----------



## Apocalypsee

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I never did get to test out the 1363's in my zero. I loved the 1361's in the amp but I only had a pair of mdip 1363's so I didn't bother to get any adapters. One of my other favorite LT opamps was the 1208 but that's a dual. I believe the lt1224 is a single channel version of it based on the data on the LT site. I preferred LT's high speed opamps before I picked up some opa earths from kingwa.
	

	
	
		
		

		
		
	


	




 Is it just me or do those 2 caps look like the tops are bulging a bit?_

 

I have LT1361 but I put it on my dad VSPS (Very Simple Phono Stage) for his turntable. He likes it, and I liked it too 
	

	
	
		
		

		
		
	


	




 Thanks for the recommendation, I have ordered LT1028 yesterday, I feel guilty for requestiong a lot of free sample from them 
	

	
	
		
		

		
		
	


	




 Those caps are fine, probably because of the flash that makes it look buldge like that


----------



## Cynips

Quote:


  Originally Posted by *loveyouso* /img/forum/go_quote.gif 
_I don't understand you guys... why stick to a very old opamp like the LT1057 and LT1056, which have high treble distortion too, according to: http://www.sg-acoustics.ch/analogue_...distortion.pdf_

 

Because I go by what I hear, not what is measured.

 Tried out the OPA2211AIDDA the last few days, and it too is a very good opamp. Clean and balanced sound with good instrument separation. Just maybe a tad overdone mid bass and not as solid as the LME49720HA, but music is fun to listen to with this one. The LT1057ACN8 still has more of a natural presence which makes my headphones "disappear," distortion or not...

 Just soldered the LME49722MA onto adapters but I'll have to wait until tonight to get any peace and quiet.


----------



## SpudHarris

Quote:


  Originally Posted by *loveyouso* /img/forum/go_quote.gif 
_You guys are missing something by not hearing the LT1122. If you do, be sure to link the pins 7 and 8 of each chip together, for a 25% speed increase yielding better microdynamics. (do you trust me?)_

 

Any resitors between or just solder bridging 7-8 pins? I've looked on Farnel and these aren't overly cheap so does any one else apart from Andrea have experience of the LT1122?

 I'm using the LT1124 at present which is a fantastic chip, lightning fast and details a plenty. The LT1124 was recommended by Ryuzoh from Fi-Quest who are manufacturing the ibasso OEM amp (on my wish list)


----------



## leeperry

Quote:


  Originally Posted by *loveyouso* /img/forum/go_quote.gif 
_Bottom line: the LT1363 is my choice._

 

until tomorrow, anyway 
	

	
	
		
		

		
		
	


	




 so do you think you can match/improve the low end bass response/soundstage of the 49720HA? you can prolly improve its trebles(that are quite whiny), but g*ddamn its bass and headstage are just "spot-on" to me, and the mids sound out of this world on electrostatic microphones (U87 and so) on my current setup 
	

	
	
		
		

		
		
	


	




 I've got a bunch of LT1364CN8, worth a try? LT told me it'd be the best choice for audio.


----------



## shrisha

Question to Opamps Gurus.

 Thinking to get this cutie:

Super Slim Metal cMOY Headphone Amp (Ocean Blue Ver.) - eBay (item 250488848323 end time Sep-26-09 00:27:42 PDT)

 Since it based on OPA2227 and OPA2227 is a poop, there is no way that it will stay there. What alternative could be the best for this board?
 Thank you.


----------



## leeperry

Quote:


  Originally Posted by *loveyouso* /img/forum/go_quote.gif 
_Surely! It's an opamp that sounds quite natural (if treated correctly), plus it's unusually docile for a fast bipolar opamp.

 That said, 2x LT1363 is audibly better._

 

will the 1364 match/improve the low end bass response/soundstage of the 49720HA? it seems to be the best you can get so far to me 
	

	
	
		
		

		
		
	


	




 it cuts the soundstage in many many slices(so cool on the super-wide cd3k headstage 
	

	
	
		
		

		
		
	


	




), and it fetches the bass really really low.

 this 30" FLAC sample is quite amazing in this combo: MEGAUPLOAD - The leading online storage and file delivery service

 the strange sound on the left channel is literally living a life of its own


----------



## ROBSCIX

Quote:


  Originally Posted by *shrisha* /img/forum/go_quote.gif 
_Question to Opamps Gurus.

 Thinking to get this cutie:

Super Slim Metal cMOY Headphone Amp (Ocean Blue Ver.) - eBay (item 250488848323 end time Sep-26-09 00:27:42 PDT)

 Since it based on OPA2227 and OPA2227 is a poop, there is no way that it will stay there. What alternative could be the best for this board?
 Thank you._

 

I wouldn't say it is "poop" as your stating. It has a great bass response and some like it mainly for that reason. However, if your comparing with the high grade opamps you can find today then the OPA2227 might lack in certain areas. I think the guy may have used this one for extra bass on his phones.
 There are some better opamps out there though.

 A quick choice would be the OPA2134.. which has a better mid/high range.
 You can try a LM4562NA or possibly other from the family. I have never used Cmoy so I am unsure what would work or not work.


----------



## ROBSCIX

I have sent my dual LME49710HA -dual metal can opamps to a few other people and they have verified my findings. They both say these opamps surpass the dual channel siblings.
 Many of use that have done extensive testing with opamps know dual single channel modules will usually always surpass a single dual channel module.
 Both state there is improved soundstage and high end extension a lower mid bass range but better overall bass extension. I am interested in making some
 other dual TO-99 modules... Will post my pics once they are built


----------



## leeperry

ah well, over-analyzing the 49720HA....I think it cuts the SS in too many slices(more than there is on the recordings for sure), and the mids carry some nasty resonances(fantastic for movies dialogs, quickly fatiguing on music)...that I should kill w/ an EQ, but op-amps make for a far more natural EQ than some crappy VST plugin 
	

	
	
		
		

		
			





 still the low end bass is fantastic...I'll roll the LT1364CN8 tomorrow


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I have sent my dual LME49710HA -dual metal can opamps to a few other people and they have verified my findings. They both say these opamps surpass the dual channel siblings.
 Many of use that have done extensive testing with opamps know dual single channel modules will usually always surpass a single dual channel module.
 Both state there is improved soundstage and high end extension a lower mid bass range but better overall bass extension. I am interested in making some
 other dual TO-99 modules... Will post my pics once they are built_

 

Great! I just received my BD adapters today. Now I'm just waiting on the LME49710HAs and OPA1611s to arrive.


----------



## ROBSCIX

BD adapters? -are you using the LME49710HA as a single channel unit on a single TO-99 adapter?


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_BD adapters? -are you using the LME49710HA as a single channel unit on a single TO-99 adapter?_

 

I'm soldering 2 of them directly to a 2 DIP8 to 1 DIP8 adapter.

Single-to-dual Op-AMP Adapter - DIP version (p/n 021001)


----------



## ROBSCIX

Yes, I figured you could so it this way using different adapters to get the one you want.

 SO your going to solder the TO-99 to the dual dip8 to single dip 8 adapter and use them this way? _that would works for sure.

 Try them out as they have been getting great feedback, well from me and others that have tried them.


----------



## leeperry

ok I've put the LT1364CN8, I've also taken out the third op-amp(that is only used as a buffer for the line-out)...on the HD2 you can use both the HP/line-out simultaneously, I figured it would only increase the SQ 
	

	
	
		
		

		
		
	


	




 anyway, the mids are not resonating like the 49720HA....and the SS is more natural, but I find it somehow boring. it'd be like waking up sober after a whole night of baking. sound is flat, but maybe that's how it's supposed to be!

 that's how nasty op-amps are, the human brain quickly adapts to "wrongly" sounding op-amps...and there's that WOW factor some parts give you at first impression, that quickly fades out.

 I understand some ppl love/hate the HD800 'coz it doesn't try to impress you. that's the feeling I get from the 1364, it seems to feed you w/ whatever is on the recording. no uber-thin SS slicing, no resonating mids(teh audiophile trick!).

 as LT told me: 
  Quote:


 Audio is not an application that we have focused on, but our parts are often selected for high-end systems. Some good parts to consider include:
 LT1468 (low distortion, low current noise, low voltage noise)
 LT1678
 LT1364
 LT6231 (for lower supply voltage apps)

 Of the parts listed below, the 1364 is available in DIP-8 so maybe that's your best choice. One of our guys who plays with this part in the lab reported that he saw distortion performance that was even better than is suggested by the graphs in the data sheet. He said it was low to the point that he had trouble measuring it. 
 

..to be continued


----------



## leeperry

indeed, the LT1364CN8 sounds disturbingly natural....it doesn't improve bad recordings, what you hear is what you get..on killer U87 voice recordings, you get that feeling to be in the studio cabin. it's not HiFi, it's natural 
	

	
	
		
		

		
		
	


	




*PS:* http://www.head-fi.org/forums/f6/i-like-lt1364-162545/
  Quote:


 I really like these! Very nice, neutral and detailed


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I'm soldering 2 of them directly to a 2 DIP8 to 1 DIP8 adapter.

Single-to-dual Op-AMP Adapter - DIP version (p/n 021001)_

 

Can you post your impressions of both chips/module when you get them built?


----------



## SpudHarris

The LME49710HA's are superb indeed, but the NA (DIP) version on a Class A adapter is better still. I can't choose which I like best as my favourite OpAmp LME49710NA (Class A) or AD797AR (Class A).

 I've been testing all night and find the OPA228 to be a contender also, very smooth but lovely details and very musical. On Andreas recommendation I have ordered a couple of OPA132UA's to see what all the fuss was about and also a couple of LT1363CN8's. I'll obviously be gunning for him should I find them to be absolute pants


----------



## ROBSCIX

If the TO-99 modules are known to be better opamps then the chip versions, maybe you should try biasing a To-99 opamp into class A operation. Should work right? Such as a special class A adapter for one of the LME49710HA opamps. This might give you better sound still over the NA chip version.
 I still like my dual LME49710HA module...


----------



## leeperry

I still have these ones to try:
 LT1124ACN8
 LT1213ACN8
 LT1355CN8
 LT1361CN8 
 LT1469IN8
 LT1677IS8
 LT1678IS8

 from what I understand the 1469 is like the 1364, but w/ less bass and more whining trebles: http://www.head-fi.org/forums/f5/lit...olling-304261/

 maybe the 1361 would be a good roller? anyway, I'm happy so far w/ the 1364...the low end bass is great, the mids very nice and the trebles sorta dark 
	

	
	
		
		

		
		
	


	




*PS: *hah, it's giving lotsa details in the mids the 49720HA was simply making resonate as hell


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Can you post your impressions of both chips/module when you get them built?_

 

You bet.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_You bet._

 

Post a pic also, I am interested in how your going to do this. I know how in thoery but want to see the finished module.


----------



## Pluto2

how different is LT1358 compared with LT1364? : )


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## leeperry

1358 had some ugly trebles IIRC, I'd say the 1364 is well worth a sample order 
	

	
	
		
		

		
		
	


	




 but again, it aims at being natural and flat. some very slight EQ on top and you'll soon reach Valhalla(as Patrick82 would say): http://www.head-fi.org/forums/f4/how...ml#post6026141


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_1358 had some ugly trebles IIRC, I'd say the 1364 is well worth a sample order 
	

	
	
		
		

		
			



_

 

I checked out the datasheet on that LT1364 to see if it would suit my amp. Crikey! It has a high input bias current: 2 uA ! That could result in some excessive DC offset on the outputs if you're not careful. It would pay to check for DC offset if you're using this in a DC-coupled circuit.


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_If the TO-99 modules are known to be better opamps then the chip versions, maybe you should try biasing a To-99 opamp into class A operation. Should work right? Such as a special class A adapter for one of the LME49710HA opamps. This might give you better sound still over the NA chip version.
 I still like my dual LME49710HA module..._

 

The problem there is that the modules are already quite tall so when on the Class A Adapter they won't fit in any of my Portable Amps. The only other alternative is making them Class A perminantely by fitting the resitor to the module and I don't real want to do that as I also roll in my PPAv2 which uses trimmers for Class A biasing so not sure how that would affect things. Could always get another two I suppose.....


----------



## morfic

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_I checked out the datasheet on that LT1364 to see if it would suit my amp. Crikey! It has a high input bias current: 2 uA ! That could result in some excessive DC offset on the outputs if you're not careful. It would pay to check for DC offset if you're using this in a DC-coupled circuit._

 

300mV in a cmoy i built and still excessively high in a commercial amp i tried this in, as popular as the chip is, i wonder if people ever look at their DC offset...............

 It may be great in a circuit designed around that chip, but it's not a good drop in chip for circuits designed around FETs or well behaved bipolars (LMEs i mean)


----------



## SpudHarris

^What about the LT1363?


----------



## murrays

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_^What about the LT1363?_

 

Look's like the input bias current is the same across the LT1363/1364/1365. Typically 0.6 uA, maximum 2.0 uA. Be forewarned! If you don't know why - I suggest you read this page: Working with Cranky Op-Amps, the section titled "High DC Offset".


----------



## leeperry

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_I checked out the datasheet on that LT1364 to see if it would suit my amp. Crikey! It has a high input bias current: 2 uA ! That could result in some excessive DC offset on the outputs if you're not careful. It would pay to check for DC offset if you're using this in a DC-coupled circuit._

 

I use it behind an AK4396 as LPF..how would that translate IRL w/o an oscilloscope?

 all I can see is "2µA *Maximum *Input Bias Current": Linear Technology - LT1364 - Dual and Quad 70MHz, 1000V/µs Op Amps

 it's a "max." spec 
	

	
	
		
		

		
		
	


	




*PS:* lol, "kill headphones very quickly"


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I use it behind an AK4396 as LPF..how would that translate IRL w/o an oscilloscope?_

 

You can check DC offset with a sensitive voltmeter.

  Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_all I can see is "2µA *Maximum *Input Bias Current": Linear Technology - LT1364 - Dual and Quad 70MHz, 1000V/µs Op Amps

 it's a "max." spec 
	

	
	
		
		

		
		
	


	


_

 

Yes, but "typical" is still 0.6 uA, it's still in the same ballpark.

  Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_PS: lol, "kill headphones very quickly" 
	

	
	
		
		

		
		
	


	


_

 

Yes, if there's enough DC present.

 O.T. - How do you enter the mu symbol (as in uA) in this editor?


----------



## leeperry

I only use cd1k/cd3k, and they're 32Ω...should be safe? but indeed, 600Ω would be a no-no 
	

	
	
		
		

		
		
	


	



  Quote:


 Ohm's Law tells us that if R2 is 100 KΩ, forcing 4 µA across it will develop a voltage of 0.4 V. 
 

the THS4032(that many ppl use) has a typical input bias current of 3uA : http://focus.ti.com/lit/ds/symlink/ths4032.pdf

 I've got a $10 voltmeter, prolly not worth a shot? I should plug a RCA adaptor to the 1/8" HP out TRS, and measure the electrical resistance on one plug?

 maybe it's time for me to try the LT1361
 what would be a "max" typical value to aim at in your opinion? 
	

	
	
		
		

		
		
	


	




 on my board, it goes through the two op-amps on the right hand, then through the +70% amplification NJM4580(I've removed the top left op-amp that was used for increased gain, it was too much to my taste) :







 even w/ fresh ears, I love the sound..and my EQ is spot-on...don't make me take them off please


----------



## SpudHarris

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_Look's like the input bias current is the same across the LT1363/1364/1365. Typically 0.6 uA, maximum 2.0 uA. Be forewarned! If you don't know why - I suggest you read this page: Working with Cranky Op-Amps, the section titled "High DC Offset"._

 

Thanks for that.

 I'm more than a little concerned now as I've been using $1000 JH13 Pro's with my P3+ and rolling all the time. Not being able to physically measure, I can normally hear some scratching from the volume pot if DC Offset is present (so I'm told). But have to say this is rare (mainly AD797's and AD825 cause this).

 What will happen to my beloved JH13's if I test the LT1363's 
	

	
	
		
		

		
		
	


	




 ??? Think I'll do initial tests from now on with a cheap pair of buds before plugging anything expensive in.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_The problem there is that the modules are already quite tall so when on the Class A Adapter they won't fit in any of my Portable Amps. The only other alternative is making them Class A perminantely by fitting the resitor to the module and I don't real want to do that as I also roll in my PPAv2 which uses trimmers for Class A biasing so not sure how that would affect things. Could always get another two I suppose....._

 

The Dual LME49710HA mdoules I build would allow for connection of the biasing resistor right under the opamp can itself. I am unsure if they would work for you, then again I could use trimmers on the opamp so you could enable or disable the biasing.


----------



## Currawong

I finally got a pair of OPA211s on a Browndog today. Lots of bass, slightly sucked-out mid-range... sounds a bit like the Earth HDAM on a chip to me. Rather expensive experiment though. I'm contemplating whether it might be worth experimenting with a cap across my preferred OP27GP I have now.


----------



## ecclesand

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_Look's like the input bias current is the same across the LT1363/1364/1365. Typically 0.6 uA, maximum 2.0 uA. Be forewarned! If you don't know why - I suggest you read this page: Working with Cranky Op-Amps, the section titled "High DC Offset"._

 

I read that and it's still over my head. I'm an MBA with enough knowledge of electronics and circuitry to be dangerous. In other words, I know squat! I have been looking at various TI datasheets for the Burr Brown opamps and sometimes this input bias current is measured as nA and sometimes it is pA. What is the difference and why are 2 opamps (by the same company) measured differently? Also, what is the best (or in my case, the easiest) way to measure DC offset? Can I simply touch the probes of a multimeter to the output RCA jacks on my DAC (which is where I'm rolling the opamps)? I certainly don't want some opamp to blow away my Millett MiniMax.

 Also, how can you tell if an opamp is oscillating? I've read it described as a whooshing sound. I haven't heard this yet so maybe I haven't experienced it?


----------



## SpudHarris

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_I finally got a pair of OPA211s on a Browndog today. Lots of bass, slightly sucked-out mid-range... sounds a bit like the Earth HDAM on a chip to me. Rather expensive experiment though. I'm contemplating whether it might be worth experimenting with a cap across my preferred OP27GP I have now._

 

I liked the OPA211's initially but you're right there is some midrange missing which isn't apparent straight away, but after listening for a while. I've seen the OP27GP mentioned a few times, is this a good OpAmp?? If so can anyone offer any info or comparisons??


----------



## ROBSCIX

I have tested the OPA211's and I find they sound quite good but our application and gear varies so opinions will also.


----------



## leeperry

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_how can you tell if an opamp is oscillating? I've read it described as a whooshing sound. I haven't heard this yet so maybe I haven't experienced it?_

 

when the 49720NA were oscillating on the Asus STX, it was so clearly audible...the sound was REALLY oscillating like a kid singing through his middle teeth. OTOH, some milder oscillation could sound like some weird resonance in the mids/trebles(fzman calls it "zing").

 I honestly think that each time I've tried the 49720NA or HA....they've always been oscillating.

 going 49720>OPA2132P is like night and day, the 2132P has always sounded so much more "stable" to me.
  Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I can normally hear some scratching from the volume pot if DC Offset is present (so I'm told). But have to say this is rare (mainly AD797's and AD825 cause this)._

 

I had this w/ the three 49720HA, two LT1634 don't do it.

 so crackling when you switch the volume is a BAD sign 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_What will happen to my beloved JH13's if I test the LT1363's 
	

	
	
		
		

		
		
	


	


_

 

the link says "kill headphones very quickly"....it might takes weeks


----------



## SpudHarris

^ Thanks leeperry 'not helping'.......
	

	
	
		
		

		
			





 Seriously though, will DC Offset kill over a period of time? Is it a heart attack or a long term illness??


----------



## leeperry

all I can say is that there's loads of caps on my board, and hopefully they'll chime out any excess DC offset.

 and I love the LT1364 SS, wider than the 49720..yet very natural, I'm hearing a lot of stuff in the mids that used to be hidden/resonating


----------



## 12Bass

AC-coupled circuits (where capacitors are used between stages) shouldn't have DC offset issues. It is often difficult to know the design unless you have a schematic. The best way to tell for sure, however, is to measure the output with a multimeter. Under 10mV is best.


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## 12Bass

Unlike a normal AC music signal, DC offset sends a constant current through the headphones. If it is sufficiently high, it can burn out the fine wire windings. A smaller DC offset can lead to other issues, as this asymmetry displaces the voice coil from its resting position, a condition which may lead to bottoming out or clicks on transients.


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## SpudHarris

Oh man...... How do I know if I'm harming my JH13's?? I own a multi-meter where do I need to measure?? Any help would be great, I don't have $1000 to waste.


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## leeperry

ok, what about that 30" FLAC sample? MEGAUPLOAD - 04 - Roy Budd - Plaything.flac

 are the first notes of the keyboard on the right channel distorted and full of ugly aliasing?

 if not, then it's time for me to roll op-amps 
	

	
	
		
		

		
		
	


	




*PS:* I'm also hearing clipping on the right channel of this song...no wonder, it's been through some major loudness war treatment


----------



## Slash47

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Oh man...... How do I know if I'm harming my JH13's?? I own a multi-meter where do I need to measure?? Any help would be great, I don't have $1000 to waste._

 

Just put it on DC, mV's.

 Measure from each channel to ground. It should be below 20mV ideally. It's as simple as that.


----------



## leeperry

ok I've just done it, I manage to measure 1 mV if I'm lucky...manual says there's a 1% error margin on this $10 voltmeter


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## murrays

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I read that and it's still over my head. I'm an MBA with enough knowledge of electronics and circuitry to be dangerous. In other words, I know squat!_

 

Ok, the basic concept is this:
 Op amps by design have a small bias current flowing at the input.
 The current flows in the input circuit resistance resulting in a voltage.
 (Ohms law gives: voltage = resistance x current).
 This input voltage is further multiplied by the gain of the stage to appear at the output. 
 Many circuits have capacitors to block the DC, so it is not a problem. 
 However, removing capacitors deemed "unnecessary" is a mod that some folks do. So just beware of these possible consequences. It is easy to check for DC offset after making changes.

  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I have been looking at various TI datasheets for the Burr Brown opamps and sometimes this input bias current is measured as nA and sometimes it is pA. What is the difference and why are 2 opamps (by the same company) measured differently?_

 

milli, micro, nano and pico are all metric prefixes (as kilo & mega).
 All just different scales for measuring the same thing, current in Amperes. 2 uA = 2000000 pA.

  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Also, what is the best (or in my case, the easiest) way to measure DC offset? Can I simply touch the probes of a multimeter to the output RCA jacks on my DAC (which is where I'm rolling the opamps)? I certainly don't want some opamp to blow away my Millett MiniMax._

 

A good way is to make up a simple test adapter to use with your multimeter. Solder some wires or terminals onto a spare headphone plug to make it easier to attach the mutimeter probes. I have one with a pair of load resistors soldered on to it.
 A quick and dirty test for DC offset is to set the output to zero (i.e. stop playing any audio) and plug and unplug the headphones several times. If you hear clicking in the headphones, this will be the DC current switching off and on as the contact is made & broken. Of course, don't use your expensive phones for this!

  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Also, how can you tell if an opamp is oscillating? I've read it described as a whooshing sound. I haven't heard this yet so maybe I haven't experienced it?_

 

An oscilloscope is best, but not always available.
 Yes, I have heard whooshing (hiss). It may vary as you move the headphone cable around, or near to sources of interference. Also the sound may change as you move your hand near the metalwork of the amp (case, heatsinks, knobs, etc).
 Another indication is excessive heat or power drain - sometimes there is more power being used at RF than at audio frequencies. This may even be destructive at the extremes. I have heard that you may generate enough RF to be picked up by a radio tuner (maybe around 1 MHz).
 I have had amps oscillating where there is no obvious audio artifact and been quite surprised to see the bad signal later on the 'scope. The load on the power supply will invoke additional distortions, but they may be subtle ("colourations") and you may need a distortion analyser to find these (even less likely to be available than an oscilloscope).


----------



## leeperry

so, any new contenders for the LT1363/64? I know mine won't get off the HD2 anytime soon. at some point I'll try the 1361/1469 I guess, eventually


----------



## ecclesand

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_Ok, the basic concept is this:
 Op amps by design have a small bias current flowing at the input.
 The current flows in the input circuit resistance resulting in a voltage.
 (Ohms law gives: voltage = resistance x current).
 This input voltage is further multiplied by the gain of the stage to appear at the output. 
 Many circuits have capacitors to block the DC, so it is not a problem. 
 However, removing capacitors deemed "unnecessary" is a mod that some folks do. So just beware of these possible consequences. It is easy to check for DC offset after making changes.



 milli, micro, nano and pico are all metric prefixes (as kilo & mega).
 All just different scales for measuring the same thing, current in Amperes. 2 uA = 2000000 pA.



 A good way is to make up a simple test adapter to use with your multimeter. Solder some wires or terminals onto a spare headphone plug to make it easier to attach the mutimeter probes. I have one with a pair of load resistors soldered on to it.
 A quick and dirty test for DC offset is to set the output to zero (i.e. stop playing any audio) and plug and unplug the headphones several times. If you hear clicking in the headphones, this will be the DC current switching off and on as the contact is made & broken. Of course, don't use your expensive phones for this!



 An oscilloscope is best, but not always available.
 Yes, I have heard whooshing (hiss). It may vary as you move the headphone cable around, or near to sources of interference. Also the sound may change as you move your hand near the metalwork of the amp (case, heatsinks, knobs, etc).
 Another indication is excessive heat or power drain - sometimes there is more power being used at RF than at audio frequencies. This may even be destructive at the extremes. I have heard that you may generate enough RF to be picked up by a radio tuner (maybe around 1 MHz).
 I have had amps oscillating where there is no obvious audio artifact and been quite surprised to see the bad signal later on the 'scope. The load on the power supply will invoke additional distortions, but they may be subtle ("colourations") and you may need a distortion analyser to find these (even less likely to be available than an oscilloscope)._

 

Wow...great information. Thank you very much!!


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_so, any new contenders for the LT1363/64? I know mine won't get off the HD2 anytime soon. at some point I'll try the 1361/1469 I guess, eventually 
	

	
	
		
		

		
		
	


	


_

 

Well I have soldered up the OPA132UA's that came in the mail today and all I can say is 'Oh my God!' these things are bloody fantastic. Andrea kept bangin' on about them so I thought I'd give them a try as the aren't uber expensive.

 You guys must try them, they are just amazing. Impactful, fantastic airy detail and such depth. Of course applications etc will make a difference but my application is different to Andreas but I agree with everything he said of them.

 My LT1363's came today also but I'm ****ting myself at the thought of killing my JH13's and not 100% sure how to check for DC Offset which judging by earlier posts there most probably is with LT1363's


----------



## leeperry

oh, yes OPA132UA! I have them too...I like the 2132P but it was maybe a bit too laid back to my taste, this one would be an improved version...but so far I'm still very unimpressed(in a good way) by the LT1364, as I said fantastic U87 voice recordings just sound so natural that it's scary.

 talk about "disappearing headphones" 
	

	
	
		
		

		
		
	


	




 well, plug a voltmeter on a RCA cable and try to measure any DC voltage...if your board has lotsa caps, it's a good guess you won't read any anyway. a proper design won't let any DC offset get to your phones IMHO.


----------



## SpudHarris

I don't think I'll be taking out the OPA132's for a while, Ive ordered some more this evening to play around with some new Class A modules (resistors the size of a grain of salt on top of brown dogs). 

 I assume from an earlier post that I can just put a jack plug like a 3.5 Neutrik in the headphone out and measure from there.


----------



## ROBSCIX

I tried the dual channel 2132 but found them cold and boring... I am pretty sure I have some OPA132's in my parts bin. Will have to give them a try and hear how they sound.
 Single channel version usually surpass thei dual channel siblings.


----------



## SpudHarris

I have 2132's a plenty but they do not resemble the OPA132's in the slightest. Just ordered my SMD 2.2k resistors for my new modules and will post a pick when complete, this will do away with the DIP socket adapter.


----------



## 12Bass

Interesting... I found the OPA2132 inferior to the OP827... sort of warm and veiled, though not as much as OPA2134. How does the OPA132 differ, and is it somehow better than the OPA827 (my current favorite FET)?


----------



## SpudHarris

I can't compare to the OPA827 yet as mine are back ordered but the OPA132 is just beautiful. I listened all night but can't say anything negative about it. Just to reiterate I also have OPA2132's lay around and to me they are just boring, flat and unimpressive and I'm amazed it's even related to the OPA132 they seem so different.


----------



## FallenAngel

Uhm... the chances that 2x OPA132 would sound absolutely any differently than a single OPA2132 is preposterous.


----------



## SpudHarris

^Well in my set up with Class A Adapters they absolutely do.

 Edit:
 There is much said within this thread about the benefits of single opamps compared to duals i.e. better channel separation, class A Biasing etc, etc.... I'll give the LME49710 / 49720 as another opamp comparison, the difference between the two is noted and even more so with the TO-99 versions. It is also worth mentioning that the OPA132 is said to be an 'updated' version. The margin of difference between the OPA132's and 2132 is the largest I've seen between a single and dual within the same family. I'm no techie but I do have a critical ear (as do most here) and can only speak as I find.


----------



## 12Bass

My experience comparing 2 x OPA211 with the OPA2211A suggested that they sound very, very similar. Definitely curious as to why the OPA132 might be so much better than the dual version. Have you tried them without the biasing resistors in place?


----------



## Voodoochile

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Interesting... I found the OPA2132 inferior to the OP827... sort of warm and veiled, though not as much as OPA2134. How does the OPA132 differ, and is it somehow better than the OPA827 (my current favorite FET)?_

 

The 134/2134 VS the 132/2132 is simply that the 132/2132 is the same chip, but with tighter and better specs- though those tighter specs fall outside the realm of applicability within the scope of an audio application. TI thus bins the 134/2134 as an "audio grade", meaning that in that application it will perform the same as the 132/2132, but at a lower point of price.

 If you were pushing the chip anywhere near it's design limits, which doesn't happen in an audio application, then the 132/2132 would be a better choice between the two chips.

 The dual-channel versus single-channel thing just means what it sounds like, there are two op-amps on the wafer, and they share power pins. You can share the rails inside the chip, or outside the chip, whatever your preference. Sure you could have discrete power supplies (for whatever reason you choose), but if you were going discrete with your PSU, you would probably not stop there and go discrete with the amplification and buffering stages as well.

 I'd make the gross analogy that it would be akin to running a pair of really high-end tires on one axle, and running recaps on the other. It's an exaggeration of the difference, but the philosophy is about the same.


----------



## qusp

got some OPA1611 and OPA1612 and OPA2110A on the way, gonna play around with Class A on the 1611


----------



## Slash47

Quote:


  Originally Posted by *Voodoochile* /img/forum/go_quote.gif 
_The 134/2134 VS the 132/2132 is simply that the 132/2132 is the same chip, but with tighter and better specs- though those tighter specs fall outside the realm of applicability within the scope of an audio application. TI thus bins the 134/2134 as an "audio grade", meaning that in that application it will perform the same as the 132/2132, but at a lower point of price.

 If you were pushing the chip anywhere near it's design limits, which doesn't happen in an audio application, then the 132/2132 would be a better choice between the two chips.

 ...
_

 

On the platforms most people here 'roll opamps', the opamps work far below their capabilities.

 The 132 seems to sound better then the 134 in 'bad' circuits but the same in very good ones. Probably because the tighter specs give it more buffer, ie more can go wrong before you start noticing. It's the same when people say the AD797B is better then the A, or that 2 LM49710HA's are better then a LM4562. 

 The same thing applies when people say the LM4562 has a fake soundstage and sounds dull. I wouldn't say a Benchmark DAC1 or TP Sabre32 sounds dull.


----------



## ROBSCIX

The idea that a dual opamps module sounds better then a single dual channel chip is not new. I think it has more to do with just the power rails.
 The idea and results have been discussed in many places not just here.

 The dual LME49710HA module does sound very different the a LM4562NA. 

 Have you tested a dual LME49710HA module?


----------



## majkel

I would rather say that there are applications so bad that you don't hear the difference between the AD797A and AD797B, or LT1028 and LT1028A because they don't yet become the bottleneck. The difference you hear is due to cleaner and tighter technology applied to the superior series production not the parameters themselves.


----------



## ecclesand

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_got some OPA1611 and OPA1612 and OPA2110A on the way, gonna play around with Class A on the 1611_

 

I have been listening to the OPA1612AID for almost 2 weeks now and really like it. It has become my new favorite. Just yesterday, I received some OPA1611s and mounted them on some browndog adapters (2 to 1) and I'm burning them in now. If what other folks have said about 2 singles sounding better than 1 dual, I should be very happy.

 I too plan to get some more OPA1611s and try the class A mod.


----------



## ROBSCIX

Based on my testing and testing done by others I have spoke with thais is generally the case. This is why I built two dual 1611's before I went to the 1612's as I figured the best sound quality would be found using a dual single channel module over a dual channel version. You have both there, let us know what you think by doing a comparison.


----------



## ecclesand

I'm still waiting on the 49710HA singles. I ordered enough to ensure if I screw something up, I have some backups. With the 1611s, soldering to the bottom of the adapter (between the pins) was much easier than I thought it would be. However, while soldering the top chip (which should be easier than the bottom), I ran into a problem and actually lifted one of the traces off the bd adapter and bent one of the pins on the opamp. I think the adapter was bad....yeah, that was it...bad adapter.
	

	
	
		
		

		
			





 Anyway, I was able to repair the trace with some solder. Popped it into my DAC and nothing. Reflowed the solder on the repaired trace and still nothing. Looked at my other bd adapters and the other set of OPA1611s I had and realized there were markings indicating which way the chips should be soldered. Huge DOH!!!!
	

	
	
		
		

		
		
	


	




 Needless to say, my first set of OPA1611s died an untimely death. I will try to desolder them, but I'm not optimistic. I will give them a proper funeral. After CORRECTLY soldering the second set, they work splendidly.

 I will give impressions after about 40 hours of burn-in. That was how long I estimate it took for the 1612 to settle in and blossom.


----------



## SpudHarris

^ Nothing worse than those bad adapters Doug, I've had a few of them hehe.


----------



## leeperry

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Needless to say, my first set of OPA1611s died an untimely death. [..]
 I will give them a proper funeral._

 







 anyway, it's good that we all have a favorite now....up to now they all left me craving for more.

 and I agree w/ Slash47, I prefer the 2132P over the 2134P(stock on my card)....but again, I only used them on $150 soundcards where the 4562/49720 always sounded terrible(huge dull SS, anemic bass on the NA/MA and resonating mids)

*PS: *damn the SS of "Edwyn Collins - A Girl Like You" sounds really awesome on the LT1364


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I'm still waiting on the 49710HA singles. I ordered enough to ensure if I screw something up, I have some backups. With the 1611s, soldering to the bottom of the adapter (between the pins) was much easier than I thought it would be. However, while soldering the top chip (which should be easier than the bottom), I ran into a problem and actually lifted one of the traces off the bd adapter and bent one of the pins on the opamp. I think the adapter was bad....yeah, that was it...bad adapter.
	

	
	
		
		

		
		
	


	




 Anyway, I was able to repair the trace with some solder. Popped it into my DAC and nothing. Reflowed the solder on the repaired trace and still nothing. Looked at my other bd adapters and the other set of OPA1611s I had and realized there were markings indicating which way the chips should be soldered. Huge DOH!!!!
	

	
	
		
		

		
		
	


	




 Needless to say, my first set of OPA1611s died an untimely death. I will try to desolder them, but I'm not optimistic. I will give them a proper funeral. After CORRECTLY soldering the second set, they work splendidly.

 I will give impressions after about 40 hours of burn-in. That was how long I estimate it took for the 1612 to settle in and blossom._

 

Bummer, mistakes happen sometimes. Post your impressions once you get your testing done. I might build a set of 1612's later on today but I am still testing the 1611's I built.
 To note, on the BD adapters, some of the pads are not connected to any traces and as such are very easy to pull off with a little heat. Especially on the dual single SOIC8 to dip 8 adapters.


----------



## 12Bass

FWIW, I didn't notice much (if any) difference between 2 x OPA211 and the OPA2211A.... 

 Anyone compared OPA1611/12 with OPA211/2211A? There appears to be some confusion about the relationship between these parts. Some suggest that the OPA1611/12 have been improved somewhat, while others say that they are merely the OPA211/2211A with relaxed DC specifications and at lower cost.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Bummer, mistakes happen sometimes. Post your impressions once you get your testing done. I might build a set of 1612's later on today but I am still testing the 1611's I built.
 To note, on the BD adapters, some of the pads are not connected to any traces and as such are very easy to pull off with a little heat. Especially on the dual single SOIC8 to dip 8 adapters._

 

Yeah...I don't think it was the pad that caused them not to work. It was me putting them on backwards. I tried to desolder them with some braid and with a solder pump. Not enough patience so I tossed the entire module.


----------



## ROBSCIX

I have both yet (1611 and 211) I have never compared them directly. Some of the specifications are similar..IIRC.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Yeah...I don't think it was the pad that caused them not to work. It was me putting them on backwards. I tried to desolder them with some braid and with a solder pump. Not enough patience so I tossed the entire module.
	

	
	
		
		

		
		
	


	


_

 

No, that is not really what I meant. I meant on certain brown dog adapters, I find you can pull of certain pads very easily especially the ones that are not connected to traces. I am just mentioning it as I have seen it happen before.
 Putting them on backwards and powering them up would toast the opamp almost immediately.


----------



## FallenAngel

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_^Well in my set up with Class A Adapters they absolutely do.

 Edit:
 There is much said within this thread about the benefits of single opamps compared to duals i.e. better channel separation, class A Biasing etc, etc.... I'll give the LME49710 / 49720 as another opamp comparison, the difference between the two is noted and even more so with the TO-99 versions. It is also worth mentioning that the OPA132 is said to be an 'updated' version. The margin of difference between the OPA132's and 2132 is the largest I've seen between a single and dual within the same family. I'm no techie but I do have a critical ear (as do most here) and can only speak as I find._

 

Class-A biasing is easily done on dual or single chips, same principle.

 I think stating that there is better channel separation in single opamps vs duals is a joke - a dual opamp has the exactly same amplifier as the single, but two in one package with power pins shared. Considering power is shared in almost all amp designs, this is exactly the same thing anyway.

 As for TO-99 version of opamps, the only person I've seen say anything about that is Andrea, and he argues for the sake of arguing with little to back it up. Or maybe he hears completely differently than I do and that's another story.

 I have a pair of OPA132's on an adapter and a single OPA2132, I can't tell the difference between them at all. Not one bit, zip, nada, nothing, completely identical. I'm testing this in a CMOY I whipped up as well as 3-channel modified Sijoase Class-AB amp.


----------



## 12Bass

One trick which might help in removing SOICs is flooding both sides with solder, then quickly flicking the chip away while the solder is still molten. Takes some doing, but works better than desoldering, IME. Desolder the pads with braid afterward.


----------



## ROBSCIX

Quality desoldering tool may also be a good addition to your tool box.


----------



## crapback

I bought one of these. Amazon.com: Aoyue 701A+ Dual Function Soldering and Desoldering Station: Home Improvement I still haven't figured out exactly how to get the thing to work right. 
	

	
	
		
		

		
		
	


	




 leeperry, any chance you might be auditioning the 1361's soon? I'm still kinda itching to get someone else's opinion of them. That and I need to have my sanity double-checked every once in a while.


----------



## leeperry

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_leeperry, any chance you might be auditioning the 1361's soon? I'm still kinda itching to get someone else's opinion of them. That and I need to have my sanity double-checked every once in a while. 
	

	
	
		
		

		
		
	


	


_

 

are they really really good? sell them to me 
	

	
	
		
		

		
		
	


	




 it's prolly a bad impression, but I don't think these cheapo browndog adapters do any good to op-amps...they increase distortion, that's what their website says. I was expecting a lot from the LME49722, and it fell flat...and so did the THS4032 everyone raves about for my HD2 board.


----------



## ROBSCIX

Why would they increase distortion?


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Why would they increase distortion?_

 

I was just going to ask the same thing. I also checked their website and can't find anything related to distortion. Can you provide a link?


----------



## leeperry

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I also checked their website and can't find anything related to distortion. Can you provide a link?_

 

Single-to-dual Op-Amp Adapter (p/n 020302)
  Quote:


 Low *loss* traces 
 

it's not too far stretched to think that any theoritical advantage of going 2*single might be overcome by the "loss" due to these cheapo adapters.

 I believe someone knowledgeable in this thread said that they could easily make op-amps oscillate, where some much more pricey adapters would not.

 I don't think there is much to be expected from a $2 adapter...but well, maybe someday I'll be blown away by some chips on these adapters the same way the LT1364 does it to me atm 
	

	
	
		
		

		
		
	


	




 both the LT techsupport and Andrea advised it to me, and I can hear why...it really scales well, the more amazing the recordings the more natural they sound


----------



## SpudHarris

I use these because the Brown Dogs are sometimes too wide to fit 2 off right next to each other which is the set up in my P3 & P3+. I've used both but these are far better quality than Brown Dogs. Only thing is you have to solder the pins yourself as they come in a flat kit (see pics).


----------



## FallenAngel

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_Single-to-dual Op-Amp Adapter (p/n 020302)

 it's not too far stretched to think that any theoritical advantage of going 2*single might be overcome by the "loss" due to these cheapo adapters.

 I believe someone knowledgeable in this thread said that they could easily make op-amps oscillate, where some much more pricey adapters would not.

 I don't think there is much to be expected from a $2 adapter...but well, maybe someday I'll be blown away by some chips on these adapters the same way the LT1364 does it to me atm 
	

	
	
		
		

		
			





 both the LT techsupport and Andrea advised it to me, and I can hear why...it really scales well, the more amazing the recordings the more natural they sound 
	

	
	
		
		

		
		
	


	


_

 

That's REALLY a stretch. If a SOIC to DIP adapter can make your opamp oscillate (which it actually could with some very extreme opamps), your board has to be SO well laid out and you must have SUCH great power supply bypassing that and you shouldn't be swapping them anyway.

 As for signal loss in traces, you should be MUCH more worried about board layout and about a million other things before you even bother looking at how much signal you will lose in 2mm of opamp adapter traces.

 It really sounds like you should reconsider your priorities, single-minded obsessiveness, although common in audio, is not a good thing.


----------



## Cynips

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_Single-to-dual Op-Amp Adapter (p/n 020302)

 it's not too far stretched to think that any theoritical advantage of going 2*single might be overcome by the "loss" due to these cheapo adapters._

 

I see no reason whatsoever to think that any loss in these traces, which is even stated to be low as one of their good qualities, would add any discernible distortion - or even measurable for that matter. Anyone with such a claim will have to provide some evidence of measure if they're going to stand a chance at convincing me of distortion being added by the adapters.

 Edit: I see FallenAngel pretty much said the same thing just better put


----------



## FallenAngel

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_I see no reason whatsoever to think that any loss in these traces, which is even stated to be low as one of their good qualities, would add any discernible distortion - or even measurable for that matter. Anyone with such a claim will have to provide some evidence of measure if they're going to stand a chance at convincing me of distortion being added by the adapters._

 

Distortion and signal loss are different things, as is parasitic inductance.

 Distortion would depend on the circuit and likely the result of instability.

 Signal loss is definitely present - when you pull current through a trace that is smaller than required, you will have signal loss (or burn the trace though that's really not expected). In applications such as an opamp, this is REALLY minimal.

 Parasitic inductance of the traces and the legs of the adapter itself may actually prove to be a problem for high-speed wide-bandwidth opamps that really need power supply bypassing very close to the signal pins. This should always be handled on the PCB but if you're talking about the "average" scenario of SOIC opamp on adapter plugged into DIP socket, it shouldn't be a problem. Of course if you're sticking a BJT-input opamp into a FET circuit, you're asking for trouble anyway and the adapter is the least of your concerns.


----------



## Cynips

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Distortion and signal loss are different things, as is parasitic inductance.

 Distortion would depend on the circuit and likely the result of instability.

 Signal loss is definitely present - when you pull current through a trace that is smaller than required, you will have signal loss (or burn the trace though that's really not expected). In applications such as an opamp, this is REALLY minimal.

 Parasitic inductance of the traces and the legs of the adapter itself may actually prove to be a problem for high-speed wide-bandwidth opamps that really need power supply bypassing very close to the signal pins. This should always be handled on the PCB but if you're talking about the "average" scenario of SOIC opamp on adapter plugged into DIP socket, it shouldn't be a problem. Of course if you're sticking a BJT-input opamp into a FET circuit, you're asking for trouble anyway and the adapter is the least of your concerns._

 

Even better put. Thanks for the clarification.


----------



## murrays

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Yeah...I don't think it was the pad that caused them not to work. It was me putting them on backwards. I tried to desolder them with some braid and with a solder pump. Not enough patience so I tossed the entire module.
	

	
	
		
		

		
		
	


	


_

 

If you know your chips are fried and you have some good sharp cutters you can cut the chip off leaving the legs soldered to the pads. It is then simple to unsolder each disembodied leg. However, be careful as the cutting force can push/pull the legs enough to dislodge the pads from the PCB.


----------



## leeperry

well, signal loss cannot be good...that was my meaning, I went from memory and it was 4:30AM 
	

	
	
		
		

		
		
	


	




 and I've just received some LT1057ACN8, gonna roll these anytime soon


----------



## 12Bass

In most cases, the low-loss circuit board traces on an SOIC adapter likely have a negligible effect on the operation of audio op amps. Even a socket has a small amount of loss, as do the IC pins, and the traces on the PCB, and the component leads, and so on.... But that's making a big deal out of practically nothing. There are issues with layout to consider, but I think that worrying about adapters is probably OCD.


----------



## ROBSCIX

I think in the grand scheme of things, there are bigger things to worry about in almost any audio setup.


----------



## leeperry

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_I think that worrying about adapters is probably OCD._

 

it's all about the details! anyway, I'm not in the market for some new rolling at this point 
	

	
	
		
		

		
		
	


	




 and honestly, it might have been misjudgment...but nothing to do w/ OCD: Obsessive-compulsive disorder (OCD): Symptoms - MayoClinic.com

 OCD is what makes ppl check 50 times a day whether the door is locked, or if the TV remote is at the exact place where it should be...this sort of things


----------



## ROBSCIX

..or wonder if their opamp is the best one they can get 150 times a day.


----------



## 12Bass

FWIW, I'm at the point where I tend to accept all op amps as a compromise.... and generally spend more time listening to music than swapping chips. Do like the recent TI stuff though....


----------



## ROBSCIX

Sure, that is one way to look at it. You have gains in one area and short falls in another. I just use the ones that give me the closest signature to what I want.
 I have also been testing the discretes units out there also. 
 Everybody has different tastes in sonic signature...


----------



## leeperry

ok I've just rolled the LT1057ACN8, I very much prefer the LT1364CN8 
	

	
	
		
		

		
		
	


	




 the SS is wider, but less natural....the mids aren't natural either, and the low end bass is AWOL.

 they clearly sound one notch lower to me, ah....the mids are really wonky in comparison, "computer" sound is the best analogy I could come up w/, it sounds like a Soundblaster or sumthing...and the sound is very reverb'ed, it feels totally unrealistic(like an empty room w/ nothing remaning in the middle channel, all the audio went to the side channels). these are not going to stay 
	

	
	
		
		

		
		
	


	




 next on the list are LT1361/LT1469


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_FWIW, I'm at the point where I tend to accept all op amps as a compromise.... and generally spend more time listening to music than swapping chips. Do like the recent TI stuff though...._

 

Have you tested out any of the discretes out there?


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_ok I've just rolled the LT1057ACN8, I very much prefer the LT1364CN8 
	

	
	
		
		

		
		
	


	




 the SS is wider, but less natural....the mids aren't natural either, and the low end bass is AWOL.

 they clearly sound one notch lower to me, ah....the mids are really wonky in comparison, "computer" sound is the best analogy I could come up w/, it sounds like a Soundblaster or sumthing...and the sound is very reverb'ed, it feels totally unrealistic(like an empty room w/ nothing remaning in the middle channel, all the audio went to the side channels). these are not going to stay 
	

	
	
		
		

		
		
	


	




 next on the list are LT1361/LT1469 
	

	
	
		
		

		
		
	


	


_

 

And you came to this conclusion with the LT1057 after having them for only a few hours? Did you burn them in at all? I found it does make a difference. You may want to give it a try.


----------



## leeperry

hah! ok, I'll let them burn in for a few hours...even though the LT1364 gave right away 
	

	
	
		
		

		
			





 this nasty reverb won't go away anytime soon I'm afraid..


----------



## leeperry

right, the 1057 had to go! I'm now running the LT1361CN8 
	

	
	
		
		

		
		
	


	




 it's like a 1364, but w/o the magic in the low end....even w/ some EQ, the trebles are still whiney.

 I read on this thread that the 1469 was also like a 1364 but whinier in the trebles...and they also agreed that the 1364 was one of the best choices: Prodigy 7.1 / LT / HiFi / HD2 Fan Club
  Quote:


 with the LT1364 there is no need for any equilizer anymore...the sound is perfect for me... 
 

I guess everybody can't be wrong, including the LT techsupport(who recommended it to me as the top choice for audio), Andrea, these guys...and my ears 
	

	
	
		
		

		
		
	


	




 I still got these to try(plus the OPA132U/OPA827/OPA211), but I'll put back the 1364 and call it a day I think...I will roll them when I'll be bored to death this winter:
 LT1355CN8
 LT1469IN8
 LT1124ACN8
 LT1213ACN8


----------



## LingLing1337

Anyone wanna comment on LT1364 vs LM4562NA, which seem to be two top contenders?


----------



## ROBSCIX

I tested the LT1364 as did a few others in the STX/ST users thread and it was not a very good opamps at all. Sounded quite cold, boring etc..
 Your tastes may vary but I found nothing particularly good about them at all for audio use. The LM4562NA/LME49720NA wouls be much better then a LT1364 IMO..


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_hah! ok, I'll let them burn in for a few hours...even though the LT1364 gave right away 
	

	
	
		
		

		
		
	


	




 this nasty reverb won't go away anytime soon I'm afraid.._

 

Why would there be reverb? Seems like there is something wrong with your card.


----------



## leeperry

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_Anyone wanna comment on LT1364 vs LM4562NA_

 

majkel made a good description of the 4562 here: http://www.head-fi.org/forums/f6/aud...-v-2-a-397691/

 mostly the SS is cut in many thin slices, but there's more of them than there is on the recording itself IMO...and it's whiney and artificial.

 the 1364 is spot-on to me, I'm back on it as we speak....it's got the low end bass extension most of the other op-amps lack(except the LME49720HA, but this one has resonant mids IME), and the trebles are not whiney. plus the mids are very detailed, PRAT is high, the SS is totally 3D & natural...
	

	
	
		
		

		
		
	


	




 it!

*PS:* this 30" FLAC sample is great to test SS: http://www.megaupload.com/?d=2IL8UQLJ

 the beat should be right in the center and the strange sound far on the left, then the bass far on the right...and nothing should sound reverbed


----------



## leeperry

hah, LM4562 better than LT1364? no chance 
	

	
	
		
		

		
		
	


	




 yes "transparency" is the exact word, more than "natural"...or maybe both would apply 
	

	
	
		
		

		
		
	


	




 ok lemme locate some LT1363, but LT asks $30 of shipping costs to Europe..

 majkel didn't like the 1363 btw: http://209.85.229.132/search?q=cache...&hl=en&ct=clnk


----------



## leeperry

do you know a place that doesn't ask $30 of shipping costs to Europe for a bunch of 1028/1363?

 majkel says the 1364 is too warm, that's exactly what I like...PRAT machine 
	

	
	
		
		

		
		
	


	




 maybe I'll try the OPA132U/OPA211 later today.

  Quote:


 The LT1364 absolutely doesn't lack transparency, but it's not boringly clynical which I like for sure. 
 

http://209.85.229.132/search?q=cache...&hl=en&ct=clnk

 I guess you are RFL?


----------



## ROBSCIX

Other people have tested the LT1364 around here and their reports are not as gushing.

 I would easily take the LT1057 or LM4562/LME49720 over the LT1364....


----------



## leeperry

Quote:


  Originally Posted by *LT1363* /img/forum/go_quote.gif 
_The LT1364 does sound more natural than the LT1057... Give it a closer listen. The LT1057 (or the single LT1056 which I've also used) lacks the microdetail and the tonal transparency of the LT1363._

 

the LT1057 is simply unbearable, I guess some ppl in this thread indeed have cotton ears


----------



## SpudHarris

I've got a couple of 1363's mounted and ready to go but with all the talk of DC offset I can't bring myself to try them. Maybe I'll try later with my IE8's or Q-jays.

 My current favourites are: OPA132UA's / LT1357's / AD797's. The 1357's and the 797's sound fantastice biased to class A but I like the 132's tonality as is.....

 I got my 1363's from Farnell with postage included.....


----------



## leeperry

the 1364 sounds far better than 1358/1057 in my book...you would not regret it. I don't see what the fuss is to measure any DC leakage on your amp..


----------



## SpudHarris

Are the 1364 and 1358 the dual versions of 1363 and 1357?

 I really like the 1357's so I'm hopefull with what you say that the 1363's will be the bee's knees, the cat's whiskers, the dogs doo dah's etc 
	

	
	
		
		

		
		
	


	




 Not a fan of the 1057's, there are many many chips that are far better IMO. Never say never though I may try them again at some point with different buffers (stacked) and different G/V chips.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Are the 1364 and 1358 the dual versions of 1363 and 1357?_

 

yes.

 well, SS is natural, sound is slightly warm and PRAT is great.

 I've got some LT1363/LT1028 on order now...but the LT1364 is definitely a keeper to me so far.

 maybe it's a synergy story on my AK4396 card, many ppl agree that it sounds fantastic on that Audiotrak Prodigy thread.


----------



## SpudHarris

Cool..

 Couldn't take it any longer, I'm listening with the 1363's now. I'll leave the class A biasing untill I'm used to the signature but initial impressions are they very fast and detailed they suit Shpongle and then some!


----------



## ROBSCIX

Generally, we are all using different circuits to test and different DAC's..etc. While the Natural sound of the opamps should still come through one pamps can sound a bit different in two different circuits.
 Testing on a $100 soundcard will yeild varied results as compared to a $500 DAC...etc


----------



## leeperry

ok my friend put OPA1612/211/132U on adapters for me 
	

	
	
		
		

		
			





 I'm using the 132U right now, it misses the warmth of the LT1364 to me...and the SS doesn't really sound natural either. it doesn't have that magic touch the LT1364 has 
	

	
	
		
		

		
		
	


	




 I'll roll the OPA211 in a minute...yeah I know breaking in yada yada, but well


----------



## leeperry

so I quickly rolled OPA1612/211/132U, I would dare anyone to identify them in a DBT


----------



## SpudHarris

DBT?


----------



## crapback

Aren't you supposed to get an E-spanking if you mention double blind testing?


----------



## ecclesand

THWACK!!! Mentioning DBT is a no-no.


----------



## leeperry

these 3 op-amps sound identical to me 
	

	
	
		
		

		
		
	


	




 anyway, I still got 4 adapters...I'll keep them for the LT1028/1363.


----------



## SpudHarris

Every days a school day 
	

	
	
		
		

		
		
	


	




 What the hell is that then??


----------



## 12Bass

Dunno about OPA132U, however, the OPA211 sounds clearly different from the OPA2132, IME.


----------



## leeperry

ah well, I guess I've grown immune to the BB sound then...it'll be a tie up between 1028/1363/1364


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well I spent an evening in the company of 2 # LT1677's last night and again today but not so critically. I have to say of the LT OpAmps I've sampled I like this one the most. It's very detailed but not harsh or fatiguing, well suited to the Psy/Electronic Genre (Shpongle, Flooting Grooves, Dymons, Bluetech, Kaya Project etc...). Not overly expensive either (£5 each) for what they are. Veeeeeery Nice 
	

	
	
		
		

		
		
	


	


_

 

any comparison to the 1364?


----------



## 12Bass

The notion of "house sound" is a fallacy, IMO. I don't consider the OPA211/2211A to sound much like the OPA2132/34 at all.


----------



## leeperry

hehe, ok! well, try the 1028/1364 if you ever get the chance....the 1364 has a slightly warm sound, that reminds me of a Corda Arietta in the low end but w/ less trebles distortion and a very natural SS. it sounds heck better than all the other chips I've heard so far, it sounds "BIG".

 Gainsbourg's voice(recorded on U87) just sounds so so so natural, like if he were alive singing in front on me(no, I'm not high 
	

	
	
		
		

		
		
	


	




)

 BTW, I've found my LT1678...they are next on the list


----------



## ROBSCIX

If all those opamps are sounding identical perhaps your circuit if the limiting factor.


----------



## jcx

if all those op amps sound different perhaps your imagination is overactive?

 how do you decide between these propositions without DBT?

 I'm pretty sure measurement with say audio diff-maker would show little difference in most cases - we sould seldom be listening at levels where the device noise characteristics are audible - so where are these differences? - just in your head?

 surely the thread could stand the occasional (every few hundred pages?) reminder to newbies that there is a strongly skeptical position which is always shouted down or gettoized


----------



## FallenAngel

Uhm... jcx - listen for yourself, at least compare a couple before making such a claim. It'll cost you $20 but you'll know for yourself instead of speculating.


----------



## Apocalypsee

I'm back on using LT1677, it wasn't as bad as I heard from before. The instruments imaging definitely better than LT1363, and it seems like it don't put the vocal to center stage, and best of all, the bass is a bit more punchy so I don't need to use my subs


----------



## crossbone

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_ok I've just rolled the LT1057ACN8, I very much prefer the LT1364CN8 
	

	
	
		
		

		
		
	


	




 the SS is wider, but less natural....the mids aren't natural either, and the low end bass is AWOL.

 they clearly sound one notch lower to me, ah....the mids are really wonky in comparison, "computer" sound is the best analogy I could come up w/, it sounds like a Soundblaster or sumthing...and the sound is very reverb'ed, it feels totally unrealistic(like an empty room w/ nothing remaning in the middle channel, all the audio went to the side channels). these are not going to stay 
	

	
	
		
		

		
		
	


	




 next on the list are LT1361/LT1469 
	

	
	
		
		

		
		
	


	


_

 

I tried the LT1057 before, too. I think we have quite the same opinion about those. Especially the reverb you mentioned sounded awful to me. As if the music was played in a cheap jazz-bar/cellar or something 

 May i give you one advise? Have you yet tried the OPA2107? That's the one i'm settled with right now. For me it's hard to believe any other OPAMP will surpass these. 
 In Comparison to the LT1057 soundstage is wider, bit more detail, not so tubby mids, no reverb. For me it just makes everything a tad better 

 Greetings from Germany!
 cross


----------



## Cynips

Quote:


  Originally Posted by *Clap Hands* /img/forum/go_quote.gif 
_As much as I admire your technical competence, your views here simply prove (if there was still the need to) the extreme narrowness of the purely scientific view of reality._

 

Don't judge the scientific process based on that troll. Actually, everyone should go read a book on science theory before engaging in any discussion on the matter on an internet forum. Believe me, I'm a scientist myself and it really gets tiresome watching all the ignorance.


----------



## leeperry

Quote:


  Originally Posted by *crossbone* /img/forum/go_quote.gif 
_I tried the LT1057 before, too. I think we have quite the same opinion about those. Especially the reverb you mentioned sounded awful to me. As if the music was played in a cheap jazz-bar/cellar or something 

 May i give you one advise? Have you yet tried the OPA2107? That's the one i'm settled with right now. For me it's hard to believe any other OPAMP will surpass these._

 

alright, sounds like a plan! but I kinda gave up on BB...I'll roll this one, though 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *Clap Hands* /img/forum/go_quote.gif 
_The LT1363 is great but... like the poster above, I feel that the LT1677 is an improvement. I'll switch back in a moment.

 Regarding the OPA2107 - it is nice, better than the LT1057, but there are many better choices... starting from (the great) 2x OPA132UA thing.

 Mind you, OPA132UA, not OPA132U. The former would be the revised version of the original OPA2132 spoken of on Audio Asylum. No, I haven't myself compared the two._

 

ok! the final fight will be 1028/1363/1677 then...but this will be LT1028CS8, not ACN8(won't fit!) but music never sounded as good as the 1364 to me so far...it feels like using some very pricey external amp 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *jcx* /img/forum/go_quote.gif 
_if all those op amps sound different perhaps your imagination is overactive?

 how do you decide between these propositions without DBT?
 [..]
 surely the thread could stand the occasional (every few hundred pages?) reminder to newbies that there is a strongly skeptical position which is always shouted down or gettoized_

 

don't pay attention to the OP, he likes to prove everyone that he knows better. he's a mod on the guru3d forum, he thinks he's a mod here as well


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## SpudHarris

Hmmm don't know about all that. But I do know that the LT1363's are mighty fine Opamps in my set up. For now I think I may have found a replacement for my beloved OPA132UA's. I sometimes find an Opamp with an initial 'Wow' factor only to find them fatitiguing or lacking after a while so I'll hold back judgement for now as I've only got about 2 hours on them. They do seem to have everything though......


----------



## leeperry

Quote:


  Originally Posted by *Clap Hands* /img/forum/go_quote.gif 
_So, in absolute terms, I seem to prefer LT1677 and OPA132UA to LT1363. But you know, I've lived with the LT1363 for more than a week, it could also be that, well, I enjoy a change...

 What the OPA132UA does seem to have is a slightly drier midbass than the LT1363's and my speakers (in their current setting) seem to appreciate that, giving back an impression of better midrange articulation.._

 

the 132U has a very "digital" sound to me, the tubiness of the 1364 just sounds too good to be true.
  Quote:


  Originally Posted by *Clap Hands* /img/forum/go_quote.gif 
_The LT1028CS8 (ACN8 doesn't fit my modified little DAC either) is a top contender as well. At this level it all comes to synergy with the rest of the system (or within the DAC or other), and to personal liking. It's impossible to choose an absolute winner. 
	

	
	
		
		

		
		
	


	


_

 

yeah, hopefully I'll have a hard time choosing between the 3


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## Currawong

Ok, tried the OPA211 (whichever the DIP8 version is, sorry I forgot). It reminds me of the Moon HDAM, with slightly sucked-out mids, giving a sense of soundstage. I still prefer the OP27GP, which wins on mids and has a nice balance overall, but then I'm listening often with HF-2s at the moment. I'll try LT1028s next. The LT1364 is an interesting thought, as I remember it being generally excellent, but getting hot quickly back when I put it in the DAC section of the Zero (though I don't have a Zero now). So our crazy Italian friend is suggesting the LT1363?!?

  Quote:


  Originally Posted by *jcx* /img/forum/go_quote.gif 
_if all those op amps sound different perhaps your imagination is overactive?_

 

Their respective outputs are tonally different. They are miniaturised amplification circuits, different ones of which have different degrees of measurable distortion of an analogue music signal. I have it in mind actually to RMAA different opamps to see what different results they produce. Otherwise, it's just cheap fun mucking around with different ones.


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## FallenAngel

Just as a note - you guys really have to start stating what the opamp is ACTUALLY DOING in the circuit to have it meaningful. Some are good for I/V, others as line-drivers, others as headphone-drivers, etc. Simply saying "this one is good" means almost nothing


----------



## leeperry

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_I have it in mind actually to RMAA different opamps to see what different results they produce._

 

RMAA Testing of Audio IC Op Amps


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## SpudHarris

Well guys I have the same set up for buffers and ground/V.Ground on my P3+ which seems to work nicely with almost all Opamps I roll in L/R.

 My favourites for L/R being LT1363's then OPA132AU's then LT1357's in that order. I'm listening as I type with the 1363's and I really think they are everything I like and more..... Can't see these coming out for a while.


----------



## 12Bass

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_Ok, tried the OPA211 (whichever the DIP8 version is, sorry I forgot)._

 

OPA211/2211A are not available in DIP. I have both in SOIC, installed on BrownDog DIP adapters. Do you mean SOIC, or might you be talking about a different chip?


----------



## SpudHarris

Possibly the 2111KP?? Hmm not tried that since I got the buffers and ground set up.


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## 12Bass

Samuel Groner has published a fairly thorough test of various op amps, recently updated with the OPA211 and OPA827. Bit of a large download, but worth a look, IMO.

http://www.sg-acoustics.ch/analogue_...distortion.pdf


----------



## Slash47

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Just as a note - you guys really have to start stating what the opamp is ACTUALLY DOING in the circuit to have it meaningful. Some are good for I/V, others as line-drivers, others as headphone-drivers, etc. Simply saying "this one is good" means almost nothing 
	

	
	
		
		

		
		
	


	


_

 

Good point. Voltage is also important.

 My favorite IC's:

 LT1363/4/5
 Great for buffers, not so hot for something with high gain like I/V or amplification. Sometimes, but only sometimes, you feel like you're in the studio or concert hall... Can be a bit bright and anemic if it isn't supplied well.

 And whoever said 2x LT1363 sounds better... 
	

	
	
		
		

		
		
	


	




 AD8599/AD8597
 My favorite for pre amps and cmoy's, stuff like that. If you use it as a buffer or for I/V it's too sparkly, it should be the last one in the chain for some reason. Female vocals can take up 2/3 of the stage, like some sort of huge mythological entity is singing from the clouds. Very weird! If you like hip-hop, use this because the bass is complete awesomeness. The most detailed chip as well, surprisingly. One last thing that it's pretty unique in: some music, namely trip-hop or alt-rock or something hippy, should really 'radiate' into the room or (or your ears) like there's this bubble of sounds. That's quite difficult to achieve. You can also hear it in a good saxophone solo, when the player blows some air over the inlet (sorry for the crappy English), it really blows into your room. And when a chair creeks, you almost get a heart attack because you think something's happening in you room. (I listen loud...) Really cool! This is normally something that requires a really expensive tube or discrete output stage.

 AD797
 Awesome, but not a drop in replacement. Neutral, like a perfectly designed extension of the DAC chip itself which is a very big compliment in my book. Sounds like an intellectual AD8597. 

 AD8397
 Great for a cmoy or as an output stage when you have up to +- 9V. Great PRaT and dynamics. Not the most realistic or smooth.

 OPA(2)604
 Great with +- 20V in class A for a very cheap output stage. And it's FET. I refuse to spend on OPA627BP, so I use this when it must be FET. Neutral sound, very good actually, but it's a bit fuzzy which pisses some people off. I don't care. Good soundstage and tone.

 I'd say the coolest ones are definitely the OPA2604 and AD8599 because:

 1) They make your head bob, which is awesome.
 2) They have a cool name.
 3) They're easy to use.
 4) They're cheap. (Not that I'm cheap, but I'd rather give it to charity 
	

	
	
		
		

		
		
	


	




)
 5) They're a nice couple. (OPA2604 -> AD8599)
 6) They piss self proclaimed wannabe 'pro's' and 'engineers' off. (Who tend to be anti-social psychopaths, no offense. I only mean the wannabe's, you know who you are! 
	

	
	
		
		

		
		
	


	




) 

 Honorable mentions:
 LT1028 (AD797's nemesis), LM4562/LME49xxx

 For audio, the most useless ones imo are:
 OPA2107 (the OPA627's ugly sister), OPA2134 (worse then a NE5532), OPA2111, LT1057, OPA211 (too expensive), OPA627 (same), OPA637 (...), LM6171/2, AD843, AD845, AD826, AD823, AD744, AD8620 LT1469, AD8022 and plenty of others. I wouldn't waste my time with them because they're obsolete in my book.

 If you can afford a OPA627BP, you might as well go discrete or use a tube stage... Maybe an M3 is the lone example where a OPA637 is best.

 The only one that I have heard that is not a compromise in any way is the AD797.

 On my modded Audiotrak Prodigy HD2 soundcard with +- 12V I like:

 2x LT1364 -> LM4562, AD8599, AD8397 (hot), LT1361 (don't know why, but this sounds better here then another LT1364)
 2x OPA2604 class A 3k3 resistors -> AD8599
 2x AD8599/LT1364 -> Burson Opamp (you can fold it pretty flat so it only takes 1 extra slot if you replace some caps.)
 3x Burson Opamps (takes a lot of space)


----------



## jcx

circuit type, Vsupply are helpful guides


 as to the value of these subjective comparisons how about actually having 2 instances of the circuit you're evaluating with the different op amps being rolled in each at the same time so the listening tests can switch in the few seconds that our much higher resolution short term memory is useful - probably not just different op amps in R/L - though that's a start

 add the requirement of level matching to 0.1 dB and I'd guess that fewer than single digit % of the posted subjective opinions meet even minimal known basics for valid subjective audible comparisons

 as to why I don't "just listen" - I believe I'm as subject to sensory and psychological limitations as the rest of the human race and the above mentioned conditions/controls and a blinding protocol would be the minimum to even try to listen for artifacts way below those of good Codecs - as an example of a well documented and extensively studied subject using subjective evaluation

 Turning subjective listening impressions into actionable engineering guidance is a incomplete and controversial subject better pursued in the Sound Science forum (the gettoization I mentioned) but the occasional reminder that the implicit assumption in this thread that you can "just listen" for differences is ignoring the basics could move some to investigate the subject more closely


----------



## Slash47

The Burson is the only way I know to make a soundcard sound analogue. I always use it as the last opamp, both on the HD2 or the ST(X).

 However, the opamps before that can be ic's without it sounding 'worse'. You actually gain some detail with a AD8599, LM4562 or LT1364. It really can't be underestimated how much of an issue EMI and RFI is with these IC chips, though. Digititis is very easy to catch.

 And the HD2 does use +- 9V, but it can be modded for +-11,5 with 12V regulators. I use alkaline batteries for my own card


----------



## leeperry

ok ok, but I want numbers 
	

	
	
		
		

		
		
	


	




 someone said on a french forum that if NJM5532 was 0%, LM4562 would be 70% and the (old) burson 100%.

 quite seriously, the LT1364 sounds amazingly analog to me...I can almost see the 2" reel rolling, but I'm also using the Waves SSL EQ in foobar to kill ear resonances...this thing sounds too awesome 
	

	
	
		
		

		
		
	


	




 as you said, it often gives the feeling to be right in the studio w/ the band playing before your eyes..and the cleaner the recording, the more amazing it gets. seriously catchy.


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## ROBSCIX

Quote:


  Originally Posted by *crossbone* /img/forum/go_quote.gif 
_I tried the LT1057 before, too. I think we have quite the same opinion about those. Especially the reverb you mentioned sounded awful to me. As if the music was played in a cheap jazz-bar/cellar or something 

 May i give you one advise? Have you yet tried the OPA2107? That's the one i'm settled with right now. For me it's hard to believe any other OPAMP will surpass these. 
 In Comparison to the LT1057 soundstage is wider, bit more detail, not so tubby mids, no reverb. For me it just makes everything a tad better 

 Greetings from Germany!
 cross_

 

Why would you be hearing reverb? I can see personal taste varying from person to person but when I tested the LT1057 there was no "reverb" sound. IIRC, Cynips uses them and has never reported hearing "reverb"... I haven't tested those units in a while and don't use them personally.
 The OP2107's are a great opamp and I have uesed them with great sucess in a few circuits.


----------



## ROBSCIX

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_The Burson is the only way I know to make a soundcard sound analogue. I always use it as the last opamp, both on the HD2 or the ST(X).

 However, the opamps before that can be ic's without it sounding 'worse'. You actually gain some detail with a AD8599, LM4562 or LT1364. It really can't be underestimated how much of an issue EMI and RFI is with these IC chips, though. Digititis is very easy to catch.

 And the HD2 does use +- 9V, but it can be modded for +-11,5 with 12V regulators. I use alkaline batteries for my own card 
	

	
	
		
		

		
		
	


	


_

 

There are a few guys using discrete opamps around here on cards and external circuits. I have been testing discrete also in a few circuits and have even been testing a custom discrete which sounds very good based on initial testing. I agree with you though as I found most of the discrete I have tested bring back the "analog" flavoring to a circuit that sounds more digital stock. If that makes any sense


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## bbbretzel

Hi everybody !
 I've just put my brand new HDAM OPA MOON into the DAC section of my Zero and I'm wondering what is the best combination of opamp in the headphones section with the MOON ???
 I'm sure you've tried a million of combinations, but can you give me some advice ?


----------



## Cynips

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Why would you be hearing reverb? I can see personal taste varying from person to person but when I tested the LT1057 there was no "reverb" sound. IIRC, Cynips uses them and has never reported hearing "reverb"... I haven't tested those units in a while and don't use them personally._

 

Well, I can't for the life of me hear any "reverb" quality with the LT1057's in my setup. I'm thinking that maybe the spec's for this opamp somehow doesn't match a setup where you get such an artifact in the output signal. I'm inclined to accept that I personally have some serious synergy going on, but these negative reports make me suspect something else than just a mismatch of audio properties.


----------



## leeperry

hehe, it was dead obvious to me, the center channel just vanished to the sides and it felt like a huge hollow reverb...and crossbone just confirmed the exact same thing on his Asus ST.

 your Beyerdynamic DT150 doesn't have a very wide SS, does it? anyway, we all hear differently...and maybe the buffer op-amps matters too, I use the high gain NJM4580 to drive my headphones.

*PS:* woohah, I remember the TrueHD track of Transformers 1 was amazing....but in Transformers 2 w/ the LT1364


----------



## ROBSCIX

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_Well, I can't for the life of me hear any "reverb" quality with the LT1057's in my setup. I'm thinking that maybe the spec's for this opamp somehow doesn't match a setup where you get such an artifact in the output signal. I'm inclined to accept that I personally have some serious synergy going on, but these negative reports make me suspect something else than just a mismatch of audio properties._

 

When I tested them, I never heard any type of spacial anomolies. I liked them but this "reverb" post has me wondering what is going on with some of these circuits.
 Oh well....


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## gurubhai

I never heard any reverb from LT1057 either.
 They were a hell of a combo with the HD595, though with HD580 I experienced slightly recessed mids.
 Also they somewhat lack in lower bass.


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## SpudHarris

Quote:


  Originally Posted by *croissant* /img/forum/go_quote.gif 
_The OPA132UA makes my ears rejoice. 
	

	
	
		
		

		
		
	


	





 With Calexico's beautiful acoustic music, it's simply perfect... musical, precise, subtle, energetic... everything. It's exactly the same with the EELS' not-so-acoustic rock, etc.

 Second favorites LT1677 and LT1028.

 Third the LT1363._

 

I'm with you there reference the OPA132UA (and your earlier post reference senses) 
	

	
	
		
		

		
		
	


	




 However, I am giving the LT1363's a good trial because I think they may be my joint favorites with the OPA132's...


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## mark2410

hmm this thread feels like a different language


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## crossbone

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_When I tested them, I never heard any type of spacial anomolies. I liked them but this "reverb" post has me wondering what is going on with some of these circuits.
 Oh well...._

 


 Well i will cite myself from another thread here. There seriously is some reverb. Not that much, but it IS noticeable 

  Quote:


  Originally Posted by *crossbone* /img/forum/go_quote.gif 
_Today my first LT Samples arrived:
 2xLT1057
 2xLT1358
 2xLT1364

 After listening about 10 hours to the following cited combo:


 I swapped in the 2 LT1057 for I/V so i got:

*2xLT1057 I/V + OPA2134 Buffer*
*Headphones:* Quite similar to the 2107 actually... though some slight differences: 2107 has a wider soundstage sounds a bit more airy. Highs with LT1057 are more in the background than with the 2107. I don't mean the highs are less or something, they just position a bit more backward soundstage wise. Perhaps a little mit more refinement in highs with the 2107. Mids are stronger on the LT1057. Upper Bass is stronger, too. Deep Bass is a bit weaker, though better controlled. I can't help but with the LT1057 there's also some echo/reverb or however it is called in english. Some Dream Theater Tracks i listened to (6:00, Caught In A Web) sound as if they are presented in a Jazz-Cellar  hard to describe, but the soundstage really differs from the 2107
*Stereo Speakers:* Not tested yet, i will stay with headphones anyway, till i get some new speakers.

 Summing it up, there are some similarities with the 2107 (in terms of frequency response) but the presentation is different. I really can't tell which one is "better" both are nice. I think it depends on your type of music. The slight reverb i can hear is a bit misleading on some quiet tracks. But then the Music is much more "in your face" at higher volumes. The LT1057 are often suggested for Electronic Music and i would sign that statement.


 Bye
 cross_


----------



## crossbone

So and now i am going to swap in the LT1364 for another testing. After having the 2107 in my ST for the last weeks. I will report soon


----------



## crossbone

First impression after some Minutes:
 The LT1364 is actually more OPA2107 than the LT1057 

 No Reverb, deepbass is better on the OPA2107. Highs and "s" tones seem to be a bit harsh with the LT1364. Soundstage is smaller than with the OPA2107. But this results in a more "in your face sound" at least a bit.

 So long... i will let them burn in now


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## SpudHarris

I'm mostly using JH13 Pro's at the moment (Honeymoon Period) there seems to be a synergy between them and the P3+ set up with OPA132's in L/R. The 132's also suit my Grado 325i's though. I'm still swinging between the LT1363's and the OPA132's, guess I can have two favorite can't I?


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## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I'm still swinging between the LT1363's and the OPA132's, guess I can have two favorite can't I?_

 

nah, it's not allowed! not in this thread anyway 
	

	
	
		
		

		
			





*@Andrea:* stop changing your mind all the bloody time already 
	

	
	
		
		

		
		
	


	




 I quoted you saying a little while ago that LT1364 was the 8th world wonder..

 anyway, I will try the 1677/1678/1028/1363 in a week or so. if they sound any better than the 1364 as ±9V AK4396 LPF, I might have a seizure though


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## SpudHarris

I tried the 1677's last night as there was so much love for them and in my set up at least the 1363's were far better in every way. Just goes to show that there are so many differences and anomalies to take into account, the only way to know for sure if an Op Amp is for you is to try it for yourself 
	

	
	
		
		

		
		
	


	




 At least he's not changed his mind on the OPA132UA's


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## Reima

I replaced the OPA132U and OPA2132PA in my Pimeta V1 with LME49710HA and LME49720HA. So far I like what I hear, the sound is cleaner with more detail. On some tracks I heard details I had not heard before, to double check this I put the OPA's back in. Sure enough I was able to hear these details once I was looking for them, they were muffled and not as present as with the LME's.
 I should mention that my source is a Sony D-NF340 Discman. 
 RC


----------



## ROBSCIX

Quote:


  Originally Posted by *Reima* /img/forum/go_quote.gif 
_I replaced the OPA132U and OPA2132PA in my Pimeta V1 with LME49710HA and LME49720HA. So far I like what I hear, the sound is cleaner with more detail. On some tracks I heard details I had not heard before, to double check this I put the OPA's back in. Sure enough I was able to hear these details once I was looking for them, they were muffled and not as present as with the LME's.
 I should mention that my source is a Sony D-NF340 Discman. 
 RC_

 

THe LME's are some great opamps when used for buffer and I/V. They seem to be getting great reviews from many around here using various circuits. One of my favorites in a dual LME49710HA module that I use for a buffer in a few circuits.


----------



## LingLing1337

I posted a while back asking whether it was worth it to swap the NE5532 in the line-out in my amp for the OPA2134PA that was sitting around- wow! 

 -Better soundstaging for sure
 -More clarity and energy- I'm listening live rather than through headphones!

 Just initial impressions here. I'll swap the 2134 for an LT1364 that I have coming in a couple days, expecting good things out of that chip.


----------



## Reima

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_One of my favorites in a dual LME49710HA module that I use for a buffer in a few circuits._

 

I am waiting for my TO-99 single to dual adapters to arrive so that I can set up my dual LME49710HA module.
 RC


----------



## ROBSCIX

The 5532, is a very generic opamps but it has been used a great amount of audio gear for a long time. The 2134 has better specs then the 5532 IIRC.
 Well, I hope you have better results with the LT1364 then I did as I found it quite unremarkable compared to some others. Let us know what you find.


----------



## ROBSCIX

Quote:


  Originally Posted by *Reima* /img/forum/go_quote.gif 
_I am waiting for my TO-99 single to dual adapters to arrive so that I can set up my dual LME49710HA module.
 RC_

 

A couple other guys in the forum have them now also and they confirm what I found. They are improved over the LME49720HA, with better bass extension and improved soundstage. Their words not mine.
 Please post your impressions whe you get the units built and tested.


----------



## SpudHarris

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_Just initial impressions here. I'll swap the 2134 for an LT1364 that I have coming in a couple days, expecting good things out of that chip._

 

It's worth noting that the 1364 (dual) 1363 (single) has had mixed reviews here, possibly due to different applications or circuits. Personally I'm still loving the 1363's in my P3+ headphone amp, I haven't rolled them for anything else in about 4 days, I think they are just superb. I hope you find the same with your 1364, leeperry swears by that chip so I don't think you'll be disapointed....


----------



## Cynips

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_It's worth noting that the 1364 (dual) 1363 (single) has had mixed reviews here, possibly due to different applications or circuits. Personally I'm still loving the 1363's in my P3+ headphone amp, I haven't rolled them for anything else in about 4 days, I think they are just superb. I hope you find the same with your 1364, leeperry swears by that chip so I don't think you'll be disapointed...._

 

Just received my 1364 samples. I'll try to post my initial impressions tonight (CET). Dunno what to expect really, but either way it'll be an interesting addition to our communal knowledge-base


----------



## bbbretzel

Quote:


  Originally Posted by *bbbretzel* /img/forum/go_quote.gif 
_Hi everybody !
 I've just put my brand new HDAM OPA MOON into the DAC section of my Zero and I'm wondering what is the best combination of opamp in the headphones section with the MOON ???
 I'm sure you've tried a million of combinations, but can you give me some advice ?
	

	
	
		
		

		
		
	


	


_

 

up


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## ROBSCIX

Just depends on what you after. The Moon is quite natural but has some "tubey" flavor going on. Try some of the tried and true opamps, the LM4562NA..OPA2134, OPA2107...etc. These all offer different signatures and only you can decide which is best for you. What opamp is in there stock? -this may give us a better idea of the requirements.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_It's worth noting that the 1364 (dual) 1363 (single) has had mixed reviews here, possibly due to different applications or circuits. Personally I'm still loving the 1363's in my P3+ headphone amp, I haven't rolled them for anything else in about 4 days, I think they are just superb. I hope you find the same with your 1364, leeperry swears by that chip so I don't think you'll be disapointed...._

 

Few of us tried them in other circuits. I wouldn't say the chip is bad, but personally I think there are much better chips then the LT1364 and of course the circuit plays a large part in the overall signature also.
 Some may like them some may not, no different then any other opamp tested here.


----------



## bbbretzel

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Just depends on what you after. The Moon is quite natural but has some "tubey" flavor going on. Try some of the tried and true opamps, the LM4562NA..OPA2134, OPA2107...etc. These all offer different signatures and only you can decide which is best for you. What opamp is in there stock? -this may give us a better idea of the requirements._

 

THANK YOU for your reply
	

	
	
		
		

		
		
	


	



 I have 2 LM4562 now in my Zero with my OPA-Moon, but I try to find some single opamps to put with the 2 dual dip adapters I've bought on ebay


----------



## ROBSCIX

No problem. 
 Read through the thread and ask other owners of your unit which opamps they find work good in the circuit. Your ears are the final judge of what works best for you...


----------



## bbbretzel

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_No problem. 
 Read through the thread and ask other owners of your unit which opamps they find work good in the circuit. Your ears are the final judge of what works best for you..._

 

well... I'll try to search over the 66 pages...


----------



## leeperry

experience has taught me that you'd better talk to God than to his saints...just as reminder that's what LT advised me for op-amps aimed at audio:
  Quote:


 Audio is not an application that we have focused on, but our parts are often selected for high-end systems. Some good parts to consider include:

 LT1468 (low distortion, low current noise, low voltage noise)
 LT1678
 LT1364
 LT6231 (for lower supply voltage apps)

 Of the parts listed below, the 1364 is available in DIP-8 so maybe that's your best choice. One of our guys who plays with this part in the lab reported that he saw distortion performance that was even better than is suggested by the graphs in the data sheet. He said it was low to the point that he had trouble measuring it. 
 

I'm currently running the LT1469IN8, and I have to say that it sounds good...really good, I'm actually hearing some micro-details the 1364 seemed to be hiding, and the SS is wider...yet still very natural sounding


----------



## leeperry

hehe, the LT1469 has the same pro/cons side as the LME serie...you can basically hear flies fart if the microphone was sensitive enough(I mostly listen to U87 recordings when testing op-amps). it digs for details very very deep, and definitely needs some EQ in the 7K region to tame it down...but then afterwards, it sounds good, but less tuby than the 1364. OTOH reverb tails and guitars sound clearer...but I think it's got some nasty resonances in the trebles like the LME49___ 
	

	
	
		
		

		
		
	


	




*PS:* the Transformers 2 BD soundtrack doesn't sound as good as the 1364...way too resonant!

 time to try the LT1355, I'm on a roll


----------



## crapback

Quote:


  Originally Posted by *bbbretzel* /img/forum/go_quote.gif 
_well... I'll try to search over the 66 pages...
	

	
	
		
		

		
		
	


	





_

 


http://www.head-fi.org/forums/f5/rev...re-amp-269458/

 Penchum has a pretty good list of opamps to try in his review of the '08 zero. I personally have an earth in the dac and two earth's in the amp. For IC's in the amp my favorites were the LT1361's followed by the LT 1208's. leeperry's favorites, the LT1364's also sounded pretty sweet in the amp. I found that I liked opamps from LT's high speed line the most out of any of the IC's in my zero amp.

 A really easy mod to improve the treble output of the zero is the removal of two ceramic capacitors, one next to each opamp socket. There are pics of that here. http://www.head-fi.org/forums/f6/fra...-heart-370985/ It's as easy as clipping the leads.


----------



## leeperry

humm the LT1355 is terrible....digitalitis to the top.

 I still got these to try: LT1124ACN8/LT1213ACN8/OPA2107

 but I'm bored, back on 1364


----------



## SpudHarris

I've had the 1468's for some time now but they never really set me alight the way some do. The 1124 on the other hand I liked a lot, leeperry let us know what you think when you get to it. I'm still with the 1363's, may drop the 1124 back in later to see what I liked about it.


----------



## SpudHarris

Quote:


  Originally Posted by *codardi* /img/forum/go_quote.gif 
_aloha_

 

He's back!


----------



## SpudHarris

More than one Codardo


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I've had the 1468's for some time now but they never really set me alight the way some do. The 1124 on the other hand I liked a lot, leeperry let us know what you think when you get to it._

 

hah, ok 
	

	
	
		
		

		
		
	


	



 I was kinda getting the feeling that the higher the model number, the better it'd sound 
	

	
	
		
		

		
		
	


	




 I'll roll the last two tomorrow, because now that I've heard the 1469...I'm now hearing the bad sides of the 1364, that I wasn't hearing before


----------



## SpudHarris

Oh man now you got me thinking I may have missed something with the 1468's? did I test them before getting my buffers & ground where I like them? 
	

	
	
		
		

		
		
	


	




 I'll have to go and roll them again now you bugger 
	

	
	
		
		

		
		
	


	




 Just when I was happy with the 1363's........


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_hah, ok 
	

	
	
		
		

		
		
	


	



 I was kinda getting the feeling that the higher the model number, the better it'd sound 
	

	
	
		
		

		
		
	


	




 I'll roll the last two tomorrow, because now that I've heard the 1469...I'm now hearing the bad sides of the 1364, that I wasn't hearing before 
	

	
	
		
		

		
		
	


	


_

 

 Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Oh man now you got me thinking I may have missed something with the 1468's? did I test them before getting my buffers & ground where I like them? 
	

	
	
		
		

		
		
	


	




 I'll have to go and roll them again now you bugger 
	

	
	
		
		

		
		
	


	




 Just when I was happy with the 1363's........_

 

Great...now I have to order some 1469s. And of course, I'll have to order some 1468s to make sure the single versions don't sound better than the dual.


----------



## leeperry

well the 1364 sounds better than 1469 to my ears, there's some nasty resonances(a la 49720HA) in the trebles that I really don't like! ugly in the intro voice of Transformers 2.

 but the 1364 still "glows" a bit around 7KHz, I guess there's some room for improvement...maybe w/ the 1028/1678?

 I'll prolly roll the LT1124ACN8/LT1213ACN8 later today


----------



## ROBSCIX

Quote:


  Originally Posted by *bbbretzel* /img/forum/go_quote.gif 
_well... I'll try to search over the 66 pages...
	

	
	
		
		

		
		
	


	





_

 

well some if the same material talked about again. 
 Same units being tested by different people. There are many opamps that are meant for audio and many that people have found that are great for audio although meant for a different task. Research helps alot in this opamp hobby and if you have any questions just ask as chances are somebody may have tested it and can give you atleast a opinion.

 Many of use have very large collections and have been testing opamps for years.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Great...now I have to order some 1469s. And of course, I'll have to order some 1468s to make sure the single versions don't sound better than the dual.










_

 

It is really a crap shoot with LT opamps. They don't really have an audio product line. Although many of the best opamps from other companies have been found outside of their dedicated audio product range. Many of LT's opamps are very fast could become a issue for some based on the circuit.


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well the 1364 sounds better than 1469 to my ears, there's some nasty resonances(a la 49720HA) in the trebles that I really don't like! ugly in the intro voice of Transformers 2.

 but the 1364 still "glows" a bit around 7KHz, I guess there's some room for improvement...maybe w/ the 1028/1678?

 I'll prolly roll the LT1124ACN8/LT1213ACN8 later today 
	

	
	
		
		

		
			



_

 

Haha, yeah I rolled the 1468's again and although nice for a change they are not as good as the 1363's IMO. I'll roll the 1124 again also this evening but I really think the LT1363's and the OPA132UA's do it for me........with LT1357's and AD797's as my runners up


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well the 1364 sounds better than 1469 to my ears, there's some nasty resonances(a la 49720HA) in the trebles that I really don't like! ugly in the intro voice of Transformers 2.

 but the 1364 still "glows" a bit around 7KHz, I guess there's some room for improvement...maybe w/ the 1028/1678?

 I'll prolly roll the LT1124ACN8/LT1213ACN8 later today 
	

	
	
		
		

		
		
	


	


_

 

For the past several days, I have been giving the LT1678 another listen based on something Andrea said. It sounds very good as the line out driver of my Peridot DAC. The mids are very liquid and female vocals sound oh so very sweet. It doesn't have the bass slam as some of the other opamps, but the bass is well defined and goes fairly deep. When I first listened to it, I marked it on my opamp spreadsheet (yes, I have an opamp spreadsheet to keep track of rolling) as one I immediately liked but never gave it a second listen.

 I just received 2 LT1357 and have them on an adapter as the Peridot only has one dual opamp socket for the line out and one for the headamp driver. They sound very good...better than the LT1358 from what I remember. I will have to do a comparo of the two. Tomorrow, I should finally get the LME49710HAs as well as some 2.2K resistors for trying the class A biasing.

 I just love it when I get to fire up the soldering iron!


----------



## leeperry

*@crossbone*: so how did the OPA2107PA/LT1364 comparison go?!

  Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Haha, yeah I rolled the 1468's again and although nice for a change they are not as good as the 1363's IMO. I'll roll the 1124 again also this evening but I really think the LT1363's and the OPA132UA's do it for me........with LT1357's and AD797's as my runners up 
	

	
	
		
		

		
		
	


	


_

 

well I just tried the 1124, its nice! but it doesn't have that magic the 1364 has.

 the intro voice of Optimus Prime in the Transformers II BD doesn't sound like it's coming from large speakers(my cd1k runs the same drivers as the cd3k, and the SS is just CRAZY)...it sounds a lot less "impressive", I'd dare to say it's too polite. prolly very good for measurements instruments and so, though.

 and yesterday when I went back from 1469>1364, I had some nasty resonances in the 7KHz region....but that's the main resonance freq of my external ears anyway...and at 2:30AM, I guess the damn things would need some rest(especially after the ugly resonant trebles of the LT1469)...it sounds a lot better today at 9PM 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_For the past several days, I have been giving the LT1678 another listen based on something Andrea said. It sounds very good as the line out driver of my Peridot DAC. The mids are very liquid and female vocals sound oh so very sweet. It doesn't have the bass slam as some of the other opamps, but the bass is well defined and goes fairly deep._

 

ok sounds good! I'll prolly ask a friend to solder it on browndog's tomorrow 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_(yes, I have an opamp spreadsheet to keep track of rolling)_

 

no worries, it means you're on the right way to total madness..I also have one, full of meaningless words like "sparkling" "bright" "bass shy" "whiney" "unbearable"....and so on


----------



## SpudHarris

Ok I've tried the LT1124 again and yes it is missing a little magic.... I keep going back to the same OpAmps so I must be nearing the end of the journey 
	

	
	
		
		

		
		
	


	




 NOT!

 The LT1363's are just wonderfull in Class A, they just don't put a foot wrong to my ears.

 I've also dug out the OPA2107 and forgot just how nice that one was. Recon I've got OCD 
	

	
	
		
		

		
		
	


	




 just....... can't........ stop...... rollin..........


----------



## leeperry

yeah go ahead, compare the OPA2107 to the LT1363....I've lost faith in BB(I prefer AKM for DAC's and LT for op-amps). I also have another one from them to try I think..


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Ok I've tried the LT1124 again and yes it is missing a little magic.... I keep going back to the same OpAmps so I must be nearing the end of the journey 
	

	
	
		
		

		
		
	


	




 NOT!

 The LT1363's are just wonderfull in Class A, they just don't put a foot wrong to my ears.

 I've also dug out the OPA2107 and forgot just how nice that one was. Recon I've got OCD 
	

	
	
		
		

		
		
	


	




 just....... can't........ stop...... rollin.........._

 

Many suggest the OPA2107 is the closet you canget to the OPA627 without paying the expensive price. You have me wanting to check out the LT1363's BUT using a class A adapter. I am also working on a new adapter you may be interested in.


----------



## 12Bass

IMO, OPA827 sounds better than OPA2107. Wasn't impressed with that chip.... no experience with OPA627.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Many suggest the OPA2107 is the closet you canget to the OPA627 without paying the expensive price. You have me wanting to check out the LT1363's BUT using a class A adapter. I am also working on a new adapter you may be interested in. 
	

	
	
		
		

		
		
	


	


_

 

Ok...you and Nigel need to put up some pics when you get these adapters done.


----------



## SpudHarris

Pics on page 51 
	

	
	
		
		

		
		
	


	




 also Hi C Buffer adapters on page 50 (I think).


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Ok...you and Nigel need to put up some pics when you get these adapters done._

 

I have some ideas for a few opamp adapters I think would be good to have available.
 I have posted pics of my opamps modules I have built so far for the thread.
 Did you build your LME49710HA yet? -Waiting for pics....


----------



## leeperry

I wanted to ensure that the LT1213 was rollable, and I stumbled upon this: Google Translate

 it's broken english and I dunno what overshoot is, but it'd be a parent of LT1028...worth a shot I guess


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Ok...you and Nigel need to put up some pics when you get these adapters done._

 

I wanted to ask also, are you biasing the LME49710HA to Class A?
 If your using a opamps adapter similar to the ones I use you would have access to all the pins easily.
 Keep us posted, I know I am interested in your results.


----------



## leeperry

humm electric guitars sound kinda strange on "David Axelrod - The Mental Traveler"?!

 the bass is great, though...LT is never a let down in that department 
	

	
	
		
		

		
		
	


	




 I still rest my case that some DBT on op-amps would yield highly laughable results 
	

	
	
		
		

		
		
	


	




 you really need to concentrate and let your feelings take over your hearing to make a judgment...imagine someone would simply put stickers w/ numbers on the chips, we'd be sooo SOL 
	

	
	
		
		

		
		
	


	




http://translate.google.com/translat...n%26safe%3Doff
  Quote:


 LT1213: Moist, high-definition feel calm. No glitz. 
 

I can't really tell for "moist"..haha, but it does sound HD and the SS is wider than the 1364. 
 Kill Bill 1's BD lossless TrueHD track sounds really really good, it doesn't "glitz"


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Pics on page 51 
	

	
	
		
		

		
		
	


	




 also Hi C Buffer adapters on page 50 (I think)._

 

Oh...I've seen those already. When I get my order from Digikey tomorrow, I will solder up the same. I thought you had some new ones cookin'!

  Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I have some ideas for a few opamp adapters I think would be good to have available.
 I have posted pics of my opamps modules I have built so far for the thread.
 Did you build your LME49710HA yet? -Waiting for pics...._

 

They were backordered for a week or two, but I should finally get them tomorrow. It's like waiting for Christmas as a kid....

 I hadn't planned to bias the LME49710HAs. I bought 4 of them so 2 I will mount directly to an adapter. The other two I will probably mount on the TO-99 to DIP8 adapters and then use them in my dual adapter that I will be biasing to class A.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Oh...I've seen those already. When I get my order from Digikey tomorrow, I will solder up the same. I thought you had some new ones cookin'!_

 

I always have new ones cookin' Also have new designs in my PCB software.
 I build new modules for myself and others about once a week.
 Just built new OPA1611s and will probably build the 1612s later today.
 Also built new OPA211's last week also...
  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_They were backordered for a week or two, but I should finally get them tomorrow. It's like waiting for Christmas as a kid....

 I hadn't planned to bias the LME49710HAs. I bought 4 of them so 2 I will mount directly to an adapter. The other two I will probably mount on the TO-99 to DIP8 adapters and then use them in my dual adapter that I will be biasing to class A._

 

I have quite a few LME49710HA modules. As they work very good for various circuit positions.
 I am interested in your results to see if the bias is a worthwhile modification. This dual module is still one of my favorites out of all the opamps I have tested.


----------



## leeperry

ok time to try the LT1678! I loved the SS of the 1213, super wide a la 49720...yet very natural, and very good low end bass response. but it didn't have that little something that makes the 1364 so enjoyable o/


----------



## leeperry

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I have been giving the LT1678 [..] The mids are very liquid and female vocals sound oh so very sweet. It doesn't have the bass slam as some of the other opamps, but the bass is well defined and goes fairly deep._

 

indeed, female voices sound really great! first time I'm impressed by a chip on a browndog 
	

	
	
		
		

		
			





 time to pass the Transformers 2/Kill Bill 1 BD TrueHD lossless soundtracks test, these don't lie...and low end bass is great, as usual from LT! and SS is wider than the 1364, that's really one of its cons I think.


----------



## ecclesand

Arrrgggghhhh....stupid UPS. The LME49710HAs will be delivered tomorrow, not today. I just love how they change the status to RESCHEDULED DELIVERY with absolutely no explanation. But I digress....

 I definitely should get the resistors today and will solder up some adapters for single and dual opamps. I will try to post pics...


----------



## leeperry

I sure hope they won't sound anything like the 49720HA 
	

	
	
		
		

		
		
	


	




 anyway, I'm thinking more and more that the higher the model number on these LT chips....the better they sound!

 this 1678 seems to take the good sides of 1213(super wide SS, great low end bass), of the 1364(very true to life male voices) and adds on top very natural female voices....and w/o the nasty resonances in the trebles of the 1364(similar to the 1469).


----------



## crapback

LOL I've had fedex pull that rescheduled delivery crap on me claiming inclement weather. I was tempted to call them and ask if I could pick up my package as the inclement weather made them keep it at the hub 30 minutes from my house.


----------



## SpudHarris

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I definitely should get the resistors today and will solder up some adapters for single and dual opamps. I will try to post pics..._

 

I never used the Class A adapters for Duals as the guy who I learned from 'HiFlight' said that he hadn't managed to effectively pull it off with duals. I've seen a post or two that say it's the same method but I'm not so sure........ Hiflight really knows his stuff and I'm sure he wouldn't have said that without reason. I only buy the odd dual anyhow as I like to be able to use any singles I have in my PPA also.

 P.S. I'm still in love with the 1363's is there anything to surpass them I wonder?


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Arrrgggghhhh....stupid UPS. The LME49710HAs will be delivered tomorrow, not today. I just love how they change the status to RESCHEDULED DELIVERY with absolutely no explanation. But I digress....

 I definitely should get the resistors today and will solder up some adapters for single and dual opamps. I will try to post pics..._

 

They have done that to me a few times, I guess it means a unknown delay.
 Oh well, one more day and you will have your new LME's biased to class A.
 I hate waiting also especially when you ready to do a new mod or module!


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I never used the Class A adapters for Duals as the guy who I learned from 'HiFlight' said that he hadn't managed to effectively pull it off with duals. I've seen a post or two that say it's the same method but I'm not so sure........ Hiflight really knows his stuff and I'm sure he wouldn't have said that without reason. I only buy the odd dual anyhow as I like to be able to use any singles I have in my PPA also.

 P.S. I'm still in love with the 1363's is there anything to surpass them I wonder?_

 

These are not duals. Each is a single channel opamp put in a adapter to make a dual. I think it is not the same as trying to connect a couple of bias resistors to a dual channel opamp. I have not tried it myself yet though. I am waiting to get more components. More opamps on the way also!


----------



## leeperry

Quote:


  Originally Posted by *Apocalypsee* /img/forum/go_quote.gif 
_I'm back on using LT1677, it wasn't as bad as I heard from before. The instruments imaging definitely better than LT1363, and it seems like it don't put the vocal to center stage, and best of all, the bass is a bit more punchy so I don't need to use my subs 
	

	
	
		
		

		
		
	


	


_

 

indeed, the 1678 beats the 1364 hands down! SS is just so much wider and the trebles so much less resonant...can't wait to compare their single counterparts against the LT1028 
	

	
	
		
		

		
		
	


	




 Andrea might not be as much of a loon as he might look like...that's what years of rolling does to ya


----------



## bbbretzel

hi guys 
	

	
	
		
		

		
		
	


	



 I've just put 2 LT1361 into the Headphones section of my Zero, with an OPA-Moon as DAC opamp...

 and...
 it's difficult to explain, I'm now listening "Dido Live at Brixton academy" and the soundstage seems less open and spacy as with the LM4562, but the bass deeper and warm than with the LM4562
 I like this "bass bonus", it's colored, and, yes, the word is "warm"...
 maybe the soundstage will go larger after burning period.... (?)
 well, just a little post to explain my "feeling" with this combination


----------



## crapback

Huh, when I had the 1361's in my zero amp it had a soundstage that was almost too wide, but that was with AD797brz's in the dac. bbbretzel, did you check out the frankenzero thread at all?


----------



## leeperry

low end bass is terrible on the DIP8 4562/49720...the 1361 might not be your best choice, though.


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_indeed, the 1678 beats the 1364 hands down! SS is just so much wider and the trebles so much less resonant...can't wait to compare their single counterparts against the LT1028 
	

	
	
		
		

		
		
	


	




 Andrea might not be as much of a loon as he might look like...that's what years of rolling does to ya 
	

	
	
		
		

		
		
	


	


_

 

No way! I'll have to check the 1677's again but to my memory they were quite unremarkable. Off I go again, back in a bit no doubt to feast on a large slice of humble pie 
	

	
	
		
		

		
		
	


	




 Have you ever seen him??


----------



## bbbretzel

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_Huh, when I had the 1361's in my zero amp it had a soundstage that was almost too wide, but that was with AD797brz's in the dac. bbbretzel, did you check out the frankenzero thread at all?_

 

yes...
	

	
	
		
		

		
		
	


	




 but it's a bit scary for a novice like me !!! 
	

	
	
		
		

		
		
	


	






 I'm very impressed when I see all that we can do with a Zero DAC and some $$$


----------



## bbbretzel

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_low end bass is terrible on the DIP8 4562/49720...the 1361 might not be your best choice, though._

 

do you think there's a difference between 4562 and 49720 ? I've got both of them and I've read some posts that say "stay away from the 49720...
	

	
	
		
		

		
		
	


	




 " it doesn't sound as good as the 4562.... (?)


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_No way! I'll have to check the 1677's again but to my memory they were quite unremarkable. Off I go again, back in a bit no doubt to feast on a large slice of humble pie 
	

	
	
		
		

		
			





 Have you ever seen him?? 
	

	
	
		
		

		
		
	


	


_

 

well, after rolling the 1469 I started to hear the ugly side of the 1364...some nasty resonances in the trebles, that the 1678 simply doesn't have. the same sort of ugly stuff the 49720HA has too.

 I always wonder if the op-amps don't break-in...in a bad way. why would break-in always be positive ?! I often got that feeling w/ the 4562/49720 series. very nice for a few days, then either they broke-out, my brain suddenly refused to adapt or I dunno.

 anyway, the 1678 SS is way wider than the 1364, yet not artificial like the 49720 
	

	
	
		
		

		
		
	


	




 PS: nah, I was just kidding about Andrea...but he's typed so much on so many forums for so many years about op-amps monologues. I guess he had plenty of time to work out what sounds GOOD ^^


----------



## ROBSCIX

Quote:


  Originally Posted by *bbbretzel* /img/forum/go_quote.gif 
_hi guys 
	

	
	
		
		

		
		
	


	



 I've just put 2 LT1361 into the Headphones section of my Zero, with an OPA-Moon as DAC opamp...

 and...
 it's difficult to explain, I'm now listening "Dido Live at Brixton academy" and the soundstage seems less open and spacy as with the LM4562, but the bass deeper and warm than with the LM4562
 I like this "bass bonus", it's colored, and, yes, the word is "warm"...
 maybe the soundstage will go larger after burning period.... (?)
 well, just a little post to explain my "feeling" with this combination 
	

	
	
		
		

		
		
	


	


_

 

Your ears have to make the final call. If you have a new set try them out for a while and hear what they have to offer you. If htese aren't quite right based on what you want. Move on to something else.


----------



## ROBSCIX

Quote:


  Originally Posted by *bbbretzel* /img/forum/go_quote.gif 
_do you think there's a difference between 4562 and 49720 ? I've got both of them and I've read some posts that say "stay away from the 49720...
	

	
	
		
		

		
		
	


	




 " it doesn't sound as good as the 4562.... (?)_

 

According to National Semi the only difference between the LM4562NA and the LME49720NA is the paint on the label. The TO-99 opamps sound different over the chip opamps though. They are like any other opamps as some like them for their gear and application and others don't.


----------



## bbbretzel

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Your ears have to make the final call. If you have a new set try them out for a while and hear what they have to offer you. If htese aren't quite right based on what you want. Move on to something else._

 

Hi Robscix 
	

	
	
		
		

		
		
	


	



 tomorrow I'll try 2 x LME49860 in the headamp section... and I'll see...
 but for now, I'm going to sleep... 23h54 here in France... if I don't stop now, I'm here at least for 2 hours
	

	
	
		
		

		
		
	


	




....
 see you tomorrow for my feedback 
	

	
	
		
		

		
		
	


	



 good night


----------



## Cynips

So I've listened some to the LT1364CN8 through the headphone out of my Essence STX and I'm wondering if someone like ROBSCIX can see a pattern here. Is this chips' current output higher than what would be called low maybe?

 It's difficult to put into words, but this one doesn't sound natural - there's something weird going on. It's like everything is restrained, highs almost sound distorted(?) and lows are lacking (for want of a better word). But nothing is bad to such an extent that I would call it really faulty. It's definitely not a sonic match - question is just what properties are wrong (if any).

 Quoting from the first page of the Essence STX tweaking thread:
  Quote:


 LT1364 : I didn't like these very much. Bass seems neutral, but lacks punch. Mid and highs are well balanced, but soundstage isn't that much better than 2114. Detail is improved. Sounds too weightless. 
 

Think I more or less agree with this


----------



## ecclesand

I got my Digikey order containing some 2.2k resistors. I first soldered 2 resistors to 2 DIP sockets and then mounted them on a 2 DIP8 to 1 DIP8 BD adapter. I soldered the resistor to pins 6 and 7 on the DIP8 sockets. Excuse my sloppy soldering job...this was my first time soldering a resistor and I have big hands.











 I tested it out with some 1357 opamps I just got. I still need to do some burn-in and listening, but WOWZA! I will elaborate after some more listening. I then said to myself..."Self, why not try putting 2 resistors on 1 DIP8 socket for Dual opamps?" And so I did...
















 I soldered one resistor from Pin 8 to Pin 1. The second resistor I soldered from Pin 8 to Pin 7. I popped in my current favorite LT1678 and there is improvement across the board. The clarity improved so much that I got goosebumps listening to some Therion. That hasn't happened in a while.

 Tomorrow, I will cook up the dual LME49710HAs and post pics. I'm off to do some more listening!


----------



## Slash47

Why do you use the V+ line for class A?


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I got my Digikey order containing some 2.2k resistors. I first soldered 2 resistors to 2 DIP sockets and then mounted them on a 2 DIP8 to 1 DIP8 BD adapter. I soldered the resistor to pins 6 and 7 on the DIP8 sockets. Excuse my sloppy soldering job...this was my first time soldering a resistor and I have big hands.
_

 

Some from initial testing your enjoying what you heard over the same units without biasing?


----------



## ecclesand

Hell if I know. It was mentioned earlier in this thread that a single channel opamp can be biased to class a by adding a resistor between V+ (Pin 7) and OUT (Pin 6). So, I did the same thing with a dual channel opamp.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Some from initial testing your enjoying what you heard over the same units without biasing?_

 

Yes. The LT1678 I have been listening to for the last several days and I know it well. The improvement with biasing was immediate. Again, I'm using these as the line out driver for a Peridot (PCM1793) DAC.

 OK...SCRATCH THAT!!! I have been burning the dual class a socket in for about an hour and decided to touch the top of the chip. OUCH....hot.
	

	
	
		
		

		
		
	


	




 I'm yanking this sucker now.


----------



## Slash47

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Hell if I know. It was mentioned earlier in this thread that a single channel opamp can be biased to class a by adding a resistor between V+ (Pin 7) and OUT (Pin 6). So, I did the same thing with a dual channel opamp._

 


 Ah ok.

 It is generally accepted that using V- gives better results. See:

Biasing Op-Amps into Class A


----------



## ecclesand

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_Ah ok.

 It is generally accepted that using V- gives better results. See:

Biasing Op-Amps into Class A_

 

Good to know! Thanks for the link!


----------



## leeperry

some ppl don't believe that resistors can turn an op-amp into class A, and will simply make the IC overheat..

 it might help if the original design wasn't meant for the new op-amp specs...but it'd need an oscilloscope anyway.


----------



## ecclesand

Yeah...I think I need to quit while I still have a working DAC. I'll solder up another set of single adapters with resistors between the OUT and V-. Then I can compare the 2. As for the dual socket....I'm done...stick a fork in me.
	

	
	
		
		

		
		
	


	




 EDIT: After an hour or so using the 2 single class A adapters on the BD adapter, the chips got just as hot as with the dual class A adapter. I guess that is a normal side effect of biasing?


----------



## levin

hey guys, i have received my Zero 2009 version and put in a HDAM Moon in the DAC section, what would you all reccomend to put in headphone section. i have tried LT1364 but i find them too be too sharp(?)( essentially really high treble, no bass at all ). is there a opamp i should try that would give it a better punch.


----------



## crapback

I'm trying to remember the opamps with the best bass in my zero. I've had three earth's in it for a few weeks now which I think beat any combo of IC's I tried. My personal favorites in the amp section were the LT1361's and the LT1208's. IIRC, the 1208's had more punch.


----------



## levin

hehe i tried the HDAM earth but i prefer the HDAM sun v2 over it. i am trying HDAM moon at the moment.


----------



## crapback

The biggest bass improvement I found was when I put the two earth's in the amp section. I still haven't spent much time with the moon or sun yet. That and I couldn't fight the urge to buy a compass with the recent sale price. 
	

	
	
		
		

		
			





 I've done a few of the frankenzero mods to mine and with the treble improvements I found the sun v2 to be a bit too bright. I still have a few more mods to do to my zero yet. I have a $10 stepped attenuator coming and I'm going to replace my petp bypass caps with some pio caps. I'd recommend checking out the frankenzero thread when you get a chance.


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well, after rolling the 1469 I started to hear the ugly side of the 1364...some nasty resonances in the trebles, that the 1678 simply doesn't have. the same sort of ugly stuff the 49720HA has too.

 I always wonder if the op-amps don't break-in...in a bad way. why would break-in always be positive ?! I often got that feeling w/ the 4562/49720 series. very nice for a few days, then either they broke-out, my brain suddenly refused to adapt or I dunno.

 anyway, the 1678 SS is way wider than the 1364, yet not artificial like the 49720 
	

	
	
		
		

		
		
	


	


_

 

Well this must be a case of different circuits yealding different results as I still find the 1677's lacking in my P3+ with my current buffer and ground set up (which suits pretty much every other L/R chip). Don't get me wrong they don't sound bad as such but to my ears the 1363's are just more ballanced.

 I may give them the benefit of doubt if you guys think they are worth it and try them with different or even bypassed buffers and/or ground.


----------



## murrays

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_Ah ok.

 It is generally accepted that using V- gives better results. See:

Biasing Op-Amps into Class A_

 

Tangent's article is a good reference, but it seems to be based on the assumption that biasing the output pins to -Vcc will load the NPN devices. While this is true for many chips where the NPN device is on the "positive" side of the output, there are some that their datasheet shows having the output transistors the around the other way, i.e. the PNP device is on the "positive" side (refer LT1677/78/79, AD823, OPA1611/12, etc). 

 I suppose if you are going to experiment with such biasing, you should probably try both +ve and -ve configurations, as Doug has suggested.


----------



## murrays

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Yeah...I think I need to quit while I still have a working DAC. I'll solder up another set of single adapters with resistors between the OUT and V-. Then I can compare the 2. As for the dual socket....I'm done...stick a fork in me.
	

	
	
		
		

		
		
	


	




 EDIT: After an hour or so using the 2 single class A adapters on the BD adapter, the chips got just as hot as with the dual class A adapter. I guess that is a normal side effect of biasing?_

 

The extra biasing draws current that will generate more heat within the chip. Ohm's law will tell you current and power, from voltage and resistance. e.g. 20mA x 15 volt supply = 300 mW.

 If the heat is excessive it may be due to oscillation, by pushing the amp outside of its safe parameters. Those sockets stacked on the adapter could be enough to push a marginal setup over the edge. I don't know how output biasing would affect stability... ?


----------



## bbbretzel

Quote:


  Originally Posted by *levin* /img/forum/go_quote.gif 
_hey guys, i have received my Zero 2009 version and put in a HDAM Moon in the DAC section, what would you all reccomend to put in headphone section. i have tried LT1364 but i find them too be too sharp(?)( essentially really high treble, no bass at all ). is there a opamp i should try that would give it a better punch._

 

HI
	

	
	
		
		

		
		
	


	



 I've got exactly the same configuration in mine, there are 2 LT1361 in the headamp section... I'll test with 2 x LME49860 after work, and I'm waiting for 3 pairs of samples from LT... 
	

	
	
		
		

		
		
	


	



 more bass with the LT1361 but the soundstage seems to be too "closed" for me... I'd like the open air soundstage ....


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well this must be a case of different circuits yealding different results as I still find the 1677's lacking in my P3+ with my current buffer and ground set up (which suits pretty much every other L/R chip). Don't get me wrong they don't sound bad as such but to my ears the 1363's are just more ballanced.

 I may give them the benefit of doubt if you guys think they are worth it and try them with different or even bypassed buffers and/or ground._

 

I'll try the single versions later...but so far -even w/ fresh ears- I still very much enjoy the LT1678.

 trebles are clear(not resonating like 1364/1469/49720HA), SS is CRAZY(49720ish wide but not artificial), maybe only the low end percussion lacks a bit compared to the 1364...but it's still very much there.

 1364 gave a "live" feeling, but this one goes even further I think...and Andrea I meant "loon" as there's several threads calling you a complete mad man, nothing personal...your advices have always been much appreciated here! 
	

	
	
		
		

		
		
	


	




*EDIT:* the 1364 SS was too narrow, killing the extreme panned details...but the 1678 seems to miss the 1364 magic in the mids 
	

	
	
		
		

		
		
	


	




 maybe I'll try the OPA2107AP..


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Yes. The LT1678 I have been listening to for the last several days and I know it well. The improvement with biasing was immediate. Again, I'm using these as the line out driver for a Peridot (PCM1793) DAC.

 OK...SCRATCH THAT!!! I have been burning the dual class a socket in for about an hour and decided to touch the top of the chip. OUCH....hot.
	

	
	
		
		

		
		
	


	




 I'm yanking this sucker now._

 

Some heat would be normal operation and some would be from the Class A modification. 
 I will do some more research into this subject and see what I can find out.


----------



## ROBSCIX

Has anybody here used the OPA6X7 series for I/V?


----------



## levin

Quote:


  Originally Posted by *bbbretzel* /img/forum/go_quote.gif 
_HI
	

	
	
		
		

		
		
	


	



 I've got exactly the same configuration in mine, there are 2 LT1361 in the headamp section... I'll test with 2 x LME49860 after work, and I'm waiting for 3 pairs of samples from LT... 
	

	
	
		
		

		
		
	


	



 more bass with the LT1361 but the soundstage seems to be too "closed" for me... I'd like the open air soundstage ...._

 

yea the LT1364 is quite good for stuff like classicals and vocals. but i listen to quite a few mix of different music so when songs with good bass or beats, they aren't there.

 i usually listen to the same track with two different headphones for comparison. the AKG702 definitely have a huge soundstage in comparison to my Alessandro MS-2 but for both its still lacking the punch with these opamp. 

 i am trying to request for some AD797BRZ and OPA627AU samples but AVnet is asking me quite a few questions :X i think i also have some LME49720NA and a few LT chips coming in to test


----------



## bbbretzel

too difficult to have samples of TI chips....


----------



## leeperry

OPA2107AP ain't that ugly! I still got the 2277 to try afterwards


----------



## SpudHarris

Been rollin' most of the night and ain't gettin to enjoy the music and relax much because of this compulsion to find somthing better, arrrgh!!

 Calling it a night now and I'm back to my old faithfulls the OPA132UA's. The LT1363's are still in the wings but for now I'm gonna chillax with my new Master Margherita album and a glass of Jameson's. Later taters!


----------



## leeperry

hahaha, luckily it's a major hassle for me to roll so I don't do it every 5 mins ^^

 but the more you roll, the higher your expectations get....as you would want the good sides of all these chips, and the more of a let down it gets each time 
	

	
	
		
		

		
		
	


	




*PS:* I think I'll put back the OPA2132P...HT.Omega recommends it for their AK4396 boards, and it wasn't too bad IIRC...the mids are dead on that 2107..


----------



## you learn slowly

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Been rollin' most of the night and ain't gettin to enjoy the music and relax much because of this compulsion to find somthing better, arrrgh!!

 Calling it a night now and I'm back to my old faithfulls the OPA132UA's. The LT1363's are still in the wings but for now I'm gonna chillax with my new Master Margherita album and a glass of Jameson's. Later taters!_

 

.


----------



## you learn slowly

leeperry, let me just say this: what do you expect from a forum whose owner and chief wants to be called "Jude Mansilla", hoping that it's not his real name...?

 Surely it can't be anything too clean or too serious... in fact it isn't either.


 And yes, they did a good job with me.


----------



## you learn slowly

^^^


----------



## you learn slowly

They did an equally good job with a few other respectable members that I knew. 
	

	
	
		
		

		
		
	


	






 Tomorrow morning I'll replace the OPA132UA with the LT1028CS8 and see if I don't find the latter to sound better. I've never compared these directly before.

 I'm really interested in this comparison. Both are audio opamps that sound great... clearly, I'll keep the winner


----------



## ecclesand

Got the LME49710HAs today and mounted them...






 After about an hour of burn-in, they sound very good. I can't say with any certainty yet that they sound better than the dual version. I need more burn-in and critical listening to determine any differences. I didn't notice any difference between the opa1612 and 2 opa1611 chips.

 EDIT: Ugh...just realized I left solder on the pins. Need to clean that off post haste!


----------



## leeperry

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Got the LME49710HAs today and mounted them..._

 

hah, ghetto style! 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *you learn slowly* /img/forum/go_quote.gif 
_They did an equally good job with a few other respectable members that I knew. 
	

	
	
		
		

		
		
	


	


_

 

well, there are rules on every forum..I think head-fi is a fantastic community and a HUGE knowledge base. Sure there's many shills(I've also been offered to become one on several occasions 
	

	
	
		
		

		
		
	


	




), nolife naggers who want to turn every thread into flame wars...ignore list exists for a reason, there must like 50 ppl on mine.

 god***n, it's 3AM and I wanna roll either the 2727 or the 2132...but that 2107 doesn't sound too bad either now


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_hah, ghetto style! 
	

	
	
		
		

		
		
	


	




 well, there are rules on every forum..I think head-fi is a fantastic community and a HUGE knowledge base. Sure there's many shills(I've also been offered to become one on several occasions 
	

	
	
		
		

		
		
	


	




), nolife naggers who want to turn every thread into flame wars...ignore list exists for a reason, there must like 50 ppl on mine.

 god***n, it's 3AM and I wanna roll either the 2727 or the 2132...but that 2107 doesn't sound too bad either now 
	

	
	
		
		

		
		
	


	


_

 

Hey, I thought you gave up on the TI opamps?


----------



## leeperry

I thought so too! but maybe after some burn-in they *really* sound better?! I've got the impression that the LME/LT chips burn-out after a few days 
	

	
	
		
		

		
		
	


	




 first they sound really really nice, then they start giving ugly resonances in the trebles..ah well, I love the magic thinking towards these chips.

 One thing I know is that the LT1364 has some magic going on...something hard to explain


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I thought so too! but maybe after some burn-in they *really* sound better?! I've got the impression that the LME/LT chips burn-out after a few days 
	

	
	
		
		

		
		
	


	




 first they sound really really nice, then they start giving ugly resonances in the trebles..ah well, I love the magic thinking towards these chips.

 One thing I know is that the LT1364 has some magic going on...something hard to explain 
	

	
	
		
		

		
		
	


	


_

 

I experience the same thing. I just received the LT1364 today so I will give that a listen. I have already listened to 2 LT1363s and they sounded OK, but not that great. Not as good as the LT1678 or 2 LT1677s to my ears. I also tried the LT1028 today. I think I like it better than the LT1363s, but more listening is needed.


----------



## leeperry

"_the same thing_" what? great first impression quickly fading out? it's really annoying....I was initially totally blown away by the 1364, so amazing! and now, all it gives me is terribly resonating trebles..just like the 49720HA


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_"the same thing" what? great first impression quickly fading out? it's really annoying....I was initially totally blown away by the 1364, so amazing! and now, all it gives me is terribly resonating trebles..just like the 49720HA 
	

	
	
		
		

		
		
	


	


_

 

Yes, that same thing.


----------



## leeperry

well the 2107 after a few hours of burn-in sounds nice, but the mids are not HD enough to my taste. it feels too distorted, a la 5532/2134...the bass doesn't slam like crazy like the 2132/1364, and the mids are wonky.

 maybe it'd sound different after 3 days of burn-in? 
	

	
	
		
		

		
		
	


	




 ok it's now 3:30AM, I think it's time to put back the amazing 1364


----------



## leeperry

oh yes, the LT1364CN8 is good stuff! slightly tubby, very natural...feels like a creamy milkshake on a hot day


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_oh yes, the LT1364CN8 is good stuff! slightly tubby, very natural...feels like a creamy milkshake on a hot day 
	

	
	
		
		

		
		
	


	


_

 

I'm listening to the LT1364 right now. Pretty good! Of course, that means after a day or two, it will start to sound like ****. Oh well...at least I'll enjoy the ride until then.


----------



## leeperry

I started to hear some nasty trebles resonances after I rolled the 1469...no idea why! but I'm not rolling anything until I get my 1028/1363/1677 
	

	
	
		
		

		
		
	


	




 its SS is not very wide, but the low end bass is great, the trebles are not whiney and the mids/general sound signature is slightly tubby and sooo natural. you could almost close your eyes and think you're in the studio cabin.

 it doesn't try to impress w/ a huge SS, it aims at being natural...a quality most op-amps simply lack.

 no wonder LT recommends it as one of the top choices for audio


----------



## LuciferX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_hahaha, luckily it's a major hassle for me to roll so I don't do it every 5 mins ^^

 but the more you roll, the higher your expectations get....as you would want the good sides of all these chips, and the more of a let down it gets each time 
	

	
	
		
		

		
			





*PS:* I think I'll put back the OPA2132P...HT.Omega recommends it for their AK4396 boards, and it wasn't too bad IIRC...the mids are dead on that 2107.._

 

Please try the OPA2132P, i have a HT OMEGA with 4 x 4580 (JRC) + AKGs 701 and I want advice about greats opamps for my card


----------



## leeperry

I already tried it on the STX/ST, it's nice...but it's not mind blowing as the LT1364...which is pure bliss as AK4396 LPF, try it!


----------



## LuciferX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I already tried it on the STX/ST, it's nice...but it's not mind blowing as the LT1364...which is pure bliss as AK4396 LPF, try it! 
	

	
	
		
		

		
		
	


	


_

 

LT refuse to send me opamps 
	

	
	
		
		

		
		
	


	




 My only options are from TI or National ....


----------



## leeperry

well buy them then? they cost $4 a pop or so 
	

	
	
		
		

		
		
	


	




 they do everything so nicely, lossless movie soundtracks, reggae, rock, jazz..really cool chip!

 I'm listening to a studio demo bootleg from Marley called "Kaya Horn Mixes" and it gives that holographic sound that you're in the same room...really scary


----------



## LuciferX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well buy them then? they cost $4 a pop or so 
	

	
	
		
		

		
		
	


	




 they do everything so nicely, lossless movie soundtracks, reggae, rock, jazz..really cool chip!

 I'm listening to a studio demo bootleg from Marley called "Kaya Horn Mixes" and it gives that holographic sound that you're in the same room...really scary 
	

	
	
		
		

		
		
	


	


_

 

JAJAJA Im from Argentina, buy strange things is not easy here 
	

	
	
		
		

		
		
	


	




 What about the trebles resonances?


----------



## Pluto2

How about nice duals, with unity gain stability eroe?


----------



## Pluto2

Thanks!

 Is it true that opa1612 is the lower quality version of opa2211?


----------



## leeperry

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Is it true that opa1612 is the lower quality version of opa2211?_

 

I tried it, and it sounded perfectly identical to the OPA132U/OPA211ID. don't expect a major difference IMHO YMMV..


----------



## SpudHarris

^What do you use headphone wise to test your opamps? Cuz while the OPA211's and 1611's sounded similar (not exactly) the OPA132UA sounded nothing like to my ears. Were you critically testing or just listening to music and didn't take too much notice cuz they didn't grab you by the balls 
	

	
	
		
		

		
		
	


	




? I do find that sometimes. The ADA4898-1's were like that, I had high hopes and got real exited about them and when I popped them in and pressed play I though well that's ok but not spectacular. Some of the better LT Opamps get me straight away and I think hmmmmn that's nice I'll listen a little longer/deeper. 

 Unless someone can suggest something guaranteed to better them in my application I'm still sticking with the OPA132UA's and the LT1363's (Class A) with LT1357's in third place......


----------



## leeperry

my modded cd1k(same drivers as cd3k)

 you guys make it sound like OPA132U and OPA132UA would be night and day


----------



## SpudHarris

Well I'm listening with them now to ''The Place It Starts'' by Kuba and everything just sounds so right, deep inpactfull bassline coated with the most beautiful layers of flute, tablas and other world purcussion and samples all exactly how and where they should be. Musical. I wish some of you guys could hit the sweet spot with these, they are so underated.


----------



## leeperry

hehe, I thought you were describing the 136x for a minute...human voices sound so natural on the 1364 
	

	
	
		
		

		
		
	


	




 someone said on a Prodigy soundcards thread that this chip doesn't need any EQ, he might be just right.


----------



## ecclesand

Just settled in at my home office to get some work done and fired up the rig with the LT1364. These do sound VERY good. They are quickly becoming my favorite. I will have to A/B them with the to LT1363 on BD adapter because I don't remember the LT1363s sounding this good. The bottom end on these things are just right to my ears...deep, impactful, layered. And Lee is right, vocals sound very good.


----------



## SpudHarris

Aren't the 63's just the single versions of the 64? if so they should sound slightly better. Now where did I put that flame proof jacket??


----------



## leeperry

so 2x singles don't sound better than a single dual? due to the increased loss of the crappy browndogs maybe? 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_What about the trebles resonances?_

 

I honestly don't know....when I first tried the 49720NA on my brand new unused STX, it was oscillating like crazy(the sound was wooshy as you wouldn't believe)....so I put back the stock 2114D for a day, then put them back and the sound was OK(anemic bass and artificial SS of course).

 the STX DIP8 sockets are the lowest quality you can find on the market...both your Claro Halo and the Prodigy cards carry machined sockets, so the contacts are much tighter...yet, maybe they were poorly seated somehow 
	

	
	
		
		

		
		
	


	




 anyway, even today w/ fresh ears I can't hear any trebles resonances and vocals sound like you're right there in the studio cabin...very impressive!


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Aren't the 63's just the single versions of the 64? if so they should sound slightly better. Now where did I put that flame proof jacket?? 
	

	
	
		
		

		
			



_

 

 Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_so 2x singles don't sound better than a single dual? due to the increased loss of the crappy browndogs maybe? 
	

	
	
		
		

		
		
	


	




 I honestly don't know....when I first tried the 49720NA on my brand new unused STX, it was oscillating like crazy(the sound was wooshy as you wouldn't believe)....so I put back the stock 2114D for a day, then put them back and the sound was OK(anemic bass and artificial SS of course).

 the STX DIP8 sockets are the lowest quality you can find on the market...both your Claro Halo and the Prodigy cards carry machined sockets, so the contacts are much tighter...yet, maybe they were poorly seated somehow 
	

	
	
		
		

		
		
	


	




 anyway, even today w/ fresh ears I can't hear any trebles resonances and vocals sound like you're right there in the studio cabin...very impressive! 
	

	
	
		
		

		
		
	


	


_

 

I can't say whether the singles would sound better than the dual or vice versa, but I don't recall the LT1363s sounding this good. I need to compare...perhaps it's just my brain playing tricks on me. This happens to us older folks.


----------



## 12Bass

Reliably perceiving the difference between op amps can be very difficult, especially if one is comparing listening sessions at different times, using different music, different headphones, volume levels unmatched, etc.... easily numerous confounds.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Reliably perceiving the difference between op amps can be very difficult, especially if one is comparing listening sessions at different times, using different music, different headphones, volume levels unmatched, etc.... easily numerous confounds._

 

Very true. That is why this thread is really only about subjective opinion.
 We all have to test for ourselves of the unit in question.
 Add to the that everybody is using different circuits, applicaitons and playback gear..etc.

 I figured when I started this thread it would be a good place for people to post what units they are working with and which ones are new or worth checking out. That's all this thread is, a bunch of people testing and talking about opamps.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I can't say whether the singles would sound better than the dual or vice versa, but I don't recall the LT1363s sounding this good. I need to compare...perhaps it's just my brain playing tricks on me. This happens to us older folks.
	

	
	
		
		

		
		
	


	


_

 

Based on many of the units I have tested, A dual single channel module tends to sound better then it's dual channel brother. Perhaps it is due to circuit isolation? -I don't pretend to know exactly why this seens to happen.


----------



## levin

LT1364 is great for vocals and classicals as it has a huge sound stage which gives my akg702 and even bigger sound stage. but any music with mid bass or so is quite lacking =( so you don't hear the bass guitarist or if you do its really flat. the low level bass is quite good tho. i might need to change my combination... maybe its the HDAM moon that is causing it to be like this. i'll find out when i put in some AD797s that are coming in soon


----------



## Pluto2

Hi Nigel,

 What about AD8599, how would you rank this chip?


----------



## leeperry

LT1364 is not perfect, the mid bass might be lacking indeed...but low end is perfect(very percussive), vocals sound holographic, trebles are not whiney and SS is very natural.

 I've read a lot of praising all over the internet about the LM4562NA/49720NA....which is really uncalled for IMO. SS is too wide and meaningless, trebles are ear piercing, low end bass is completely AWOL 
	

	
	
		
		

		
		
	


	




 but good point, I might just try to add a bassy op-amp as final buffer like the OPA2111KP.


----------



## SpudHarris

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Hi Nigel,

 What about AD8599, how would you rank this chip?_

 

Good point, haven't listened to it for a while but do remember seeing it written that it has a place in any self respecting ''Rollers'' chip collection. I will have a listen this evening if I get a mo and report back


----------



## 12Bass

Just replaced the LM4562 I had in the main (1/2) outputs of my Echo Gina24 with an OPA2211A. Echo originally used NJM2068s which sound a bit hazy to me. Think it sounds a bit more vibrant and alive now with the OPA2211A. Seem to be hearing a little more detail and maybe a bit more fullness in the lows... hard to say for sure as it took some time to swap chips. Lost a couple of SMD circuit pads while doing the swap, so I doubt I'll want to do any more swapping on this card. Had to make some hardwired traces. Do think it sounds a bit better, however....


----------



## leeperry

well, I've added the OPA2111KP as buffer behind the two LT1364(used as ±9V AK4396 LPF)...and it goes through the high gain JRC4580 afterwards to drive my cd1k.

 vocals still sound good, and mid bass is improved I think, low end is even more slamming and controlled...gotta love messing w/ op-amps to shape the sound YOU want. I'll try a 2132/2604(stock)/1361 as buffer afterwards, but the 2111 is teh bass monster I think...and the 1364 are staying as LPF


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Good point, haven't listened to it for a while but do remember seeing it written that it has a place in any self respecting ''Rollers'' chip collection. I will have a listen this evening if I get a mo and report back 
	

	
	
		
		

		
		
	


	


_

 

The AD8599 seems to get recommended a great deal when asking about AD opamps. Along with the AD8620, AD8610 and others. I used this chip for awhile in a particular circuit. Post your recommendation and impressions.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Just replaced the LM4562 I had in the main (1/2) outputs of my Echo Gina24 with an OPA2211A. Echo originally used NJM2068s which sound a bit hazy to me. Think it sounds a bit more vibrant and alive now with the OPA2211A. Seem to be hearing a little more detail and maybe a bit more fullness in the lows... hard to say for sure as it took some time to swap chips. Lost a couple of SMD circuit pads while doing the swap, so I doubt I'll want to do any more swapping on this card. Had to make some hardwired traces. Do think it sounds a bit better, however...._

 

The 211's, 2211's seem to be getting good reviews from those doing the testing. I found the series quite good and built a few more modules the other day.
 If your swapping on a SMD circuit there is a adapter avialble from brown dog that allows you to solder it in to a SMD footprint and ont he other end is a Dip8 adapter. If I am understanding you correctly it may be something you might find useful for future mods on that audio interface or others. I will see if I can find the link for you.

 Edit: Here it is: SMD to Dip8 adapter


----------



## 12Bass

FWIW, I've found the AD8599 a little warmer than other Analog Devices chips that I've tried, at least in my test circuits. Low noise, and still detailed, but not as clear as LM4562 or OPA2211A. For bipolars, the OPA2211A is my present favorite. It sounds more open, natural, and alive than the LM4562, which can sound a bit thin and sterile, IMO.

 Thanks for the info about the SOIC->DIP adapters. Don't think I'll use any on this card. Wasn't really intending to be swapping at all, but figured that the OPA2211A sounded better in other circuits, so I should try it on the Gina24, as it is my main source. At the moment, I'm happy with the improvement.

 On a side note, I thought I'd compare the output of my modded Digi96/8 PST with the freshly modded Gina24. The Digi96/8 has an AD8397 at the output (which replaced an LM4562); I used this particular part because the main output can be used to drive headphones, and the AD8397 offers far more current for that purpose. 

 Anyway, even with the two cards fairly well matched in volume (within 1dB), there are noticeable differences. I'm not sure how much is the digital clocks, and how much is op amps and/or DA converters. The RME uses the AD1852, while the Echo uses the AK4393. Swapping the master and slave clocks had a noticeable effect on imaging.


----------



## ROBSCIX

I am also a fan of the 211 family. I just mentioned the adapter as you may have been planning on trying some other chips or have other circuits where it might be useful.
 I have a few circuits with SMD opamps and I think I may just design a drop in circuit to allows for replacing opamps. Similar to the adapter I showed you in theory but different in design and use.


----------



## 12Bass

Will have to try OPA1611/12 and see if they are different than OPA211/2211A. I suspect not, though I've not looked into what the numbers say.... 
	

	
	
		
		

		
		
	


	




 After listening a bit more, I'm wondering if some of the comments about the OPA2211A having a somewhat recessed midrange might be true. Though it's really difficult to say due to the time between chips and all of the other variables. I do think it sounds better than the LM4562 with my K702s. However, my Energy Pro22 speakers are already a little lean in some parts of the midrange.

 I recall when I was testing a number of op amps in my Eden bass amp that the LM4562 did a particularly nice job of clearly reproducing the midrange. When I would swap in another chip, the "voice" of my bass would become less apparent. As I recall, I thought that the OP2211A did as well or better, but sounded more open and organic, and had a bit more roundness in the lows.

 Still have LME49860, AD797, ADA4898-1, and maybe even LME49722 around waiting to be tested. Ack!

 Oh, and about the AD8599, while I've found many or the AD op amps to be somewhat forward sounding, perhaps even tending toward edgy, IMO, the AD8599 sounds quite smooth and mellow, with a nice roundness throughout. Not harsh at all, at least in my experience.


----------



## leeperry

yes apparently AD8599 is killer, but I'm not willing to pay $40 of shipping costs to Europe..

 humm I think I'd prefer the 2604 over the 2111 as buffer, bass is great but the mids sound recessed as hell...more rolling to come


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Will have to try OPA1611/12 and see if they are different than OPA211/2211A. I suspect not, though I've not looked into what the numbers say.... 
	

	
	
		
		

		
		
	


	




 After listening a bit more, I'm wondering if some of the comments about the OPA2211A having a somewhat recessed midrange might be true. Though it's really difficult to say due to the time between chips and all of the other variables. I do think it sounds better than the LM4562 with my K702s. However, my Energy Pro22 speakers are already a little lean in some parts of the midrange.

 I recall when I was testing a number of op amps in my Eden bass amp that the LM4562 did a particularly nice job of clearly reproducing the midrange. When I would swap in another chip, the "voice" of my bass would become less apparent. As I recall, I thought that the OP2211A did as well or better, but sounded more open and organic, and had a bit more roundness in the lows.

 Still have LME49860, AD797, ADA4898-1, and maybe even LME49722 around waiting to be tested. Ack!

 Oh, and about the AD8599, while I've found many or the AD op amps to be somewhat forward sounding, perhaps even tending toward edgy, IMO, the AD8599 sounds quite smooth and mellow, with a nice roundness throughout. Not harsh at all, at least in my experience._

 

I built dual 1611's the other day and they sounded quite good from just intial testing. -Meaning basic listening test to verify they work as built.
 I find the LME4562NA is a good chip but you can find ones that may be better matches for certain setups. The LM/LME series is like others, some like them and some do not. The LME49860 is fairly good going from memory. AD797 is another favorite of a few around here in one form or another.

 I find some of AD's opamps can sound very forward and agressive -if that is the right word. I guess by your post your using the AD8599 as buffer. I only tested them for I/V position. I have a few new circuits to play with so I have to build some new units for testing in these also.
 What are your thoughts on the AD8620, or dual AD8610, if you have tested them?


----------



## ecclesand

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Oh, and about the AD8599, while I've found many or the AD op amps to be somewhat forward sounding, perhaps even tending toward edgy, IMO, the AD8599 sounds quite smooth and mellow, with a nice roundness throughout. Not harsh at all, at least in my experience._

 

This mirrors my impression of the AD8599. Very smooth...almost polite. If you want the music in your face, these are not the opamps for you. The AD8620 is a bit more kicking with a punchy deep bottom end, however, I felt the highs were a little rolled off.


----------



## leeperry

I'm still undecided on what to use as a buffer between the two LT1364(used as AK4396 LPF) and the JRC4580 used to drive my phones...LME49722? OPA211? OPA192U? LT1361? ahhhhhh, the OPA2111 retains the holographic vocals of the LT1364 but the sound has lost some sparkle and earned some analog-like warmth...maybe it isn't such a bad deal, it doesn't sound like computer audio anymore, more like HiFi..

 I just want a bassy chip to get my mid-bass back from the 1364, which the 2111 achieves nicely...stock was 2604 btw.

*PS:* ooops, wrong pick...the LME49722 sounds terrible as buffer on my board...whiney/resonant/artificial as a 49720NA, god I hate that 4562ish sound


----------



## 12Bass

Sorry, no experience with AD8610/20. Got the impression it was somewhat harsh, so I didn't bother with it. Most of my applications also require chips that can take +/- 18V.

 As for AD8599, it's a bit too mellow for me, as I like a bit more detail/sparkle.


----------



## Cynips

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Very true. That is why this thread is really only about subjective opinion.
 We all have to test for ourselves of the unit in question.
 Add to the that everybody is using different circuits, applicaitons and playback gear..etc.

 I figured when I started this thread it would be a good place for people to post what units they are working with and which ones are new or worth checking out. That's all this thread is, a bunch of people testing and talking about opamps._

 

That said, I find it extremely interesting to find patterns where people with somehow similar setups reach similar conclusions - or cases where conclusions differ while setups also differ. I'm talking of what we're all trying to do here, reading about other peoples experiences and trying to figure out if that could be something for you to try out.

 I'm very intrigued by the difference in opinion about the LT1057 and LT1364. It is apparent that setups differ, but exactly what is the significant factor (if possible to discern just one or a few) determining this pattern? Maybe I'll never find out, but that doesn't make in any less interesting


----------



## Apocalypsee

My own analog out just got better, I lift the ground from it to the power supply and just leave it float just like that and voila! Not even a single noise/buzzing/hissing comes out when I put the volume to max (no music is playing of course). Now for some serious test on LT1677 vs LT1363.

 What I found is LT1363 have much deeper soundstage, and render vocal much more beautifully (more fluid and softer) than LT1677, while LT1677 gives detail on the background much more clearer (more treble?) and much more 'present' feel than LT1363, its like precision tool giving detail without sibilance. Its more like LME49720 but without being airy and too wide and artificial soundstage. But the 49720 is not as bad as 4562, which sounds way too rough and edgy (but 4562 tested on different card, XtremeMusic on CS4382 DAC and +-5V supply).

 I thinking of taking NE5534 for another spin, but nah, LT1677 gets my pick


----------



## SpudHarris

Ok, after so much talk of the LT1677's I thought I'd give them another chance but change the buffer and ground set up and man what a difference it has made.... I will do some listening today whilst out and some critical listening this evening, but at present it's looking good.


----------



## leeperry

I wonder if the 8599/1028 would give that same holographic sound to vocals as the 1364...the 1678 clearly does not.


----------



## Apocalypsee

Dang, after been using it for about an hour or so, my ear started to hurt, there is too much treble i guess. Looks like LT1677 don't have the synergy with my system after all. I wonder if there is any opamp that have the detail like LT1677 and great vocal and soundstage of LT1363? Maybe I should try AD744 or AD797 next?


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_This mirrors my impression of the AD8599. Very smooth...almost polite. If you want the music in your face, these are not the opamps for you. The AD8620 is a bit more kicking with a punchy deep bottom end, however, I felt the highs were a little rolled off._

 

I have only used them for I/V conversion on the advice of another member.
 I have yest to test them for single ended buffer.


----------



## ROBSCIX

Quote:


  Originally Posted by *Cynips* /img/forum/go_quote.gif 
_That said, I find it extremely interesting to find patterns where people with somehow similar setups reach similar conclusions - or cases where conclusions differ while setups also differ. I'm talking of what we're all trying to do here, reading about other peoples experiences and trying to figure out if that could be something for you to try out.

 I'm very intrigued by the difference in opinion about the LT1057 and LT1364. It is apparent that setups differ, but exactly what is the significant factor (if possible to discern just one or a few) determining this pattern? Maybe I'll never find out, but that doesn't make in any less interesting 
	

	
	
		
		

		
		
	


	


_

 

That is the trouble as the impressions can only go so far. People are using different circuits and different setups. Add to that personal tastes and you can get a wide variety of opinions. However, I find for the most part opinions are generally the same to some extent. I find when the odd opinion differs there is some other reason for it. I use opinions here as guide posts...never as hard and fast truths about any unit.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Sorry, no experience with AD8610/20. Got the impression it was somewhat harsh, so I didn't bother with it. Most of my applications also require chips that can take +/- 18V.

 As for AD8599, it's a bit too mellow for me, as I like a bit more detail/sparkle._

 

I have tested the AD8620 and that has a place in my collection. I am thinking of building some dual AD8610's as per suggestion of another member.
 I have yet to test the 8599 in any detail...only ever tried it for I/V....


----------



## you stink :)

For the much talked-of LT1363: this one is soothing to listen to, but after a long listen it just lacks the ultimate transparency. I'm terribly enjoying it in my 24V evolved CMOY (driving my HD238), though. 
	

	
	
		
		

		
		
	


	




 Regarding the recently-talked-of LT1677: this one has the ultimate transparency and sounds quite good overall. However, the LT1028CS8 has a more pacey bass and a more interesting tonality, so the crown must go to the latter.


 I wish I had some SMD LT1115 (do they even exist SMD? Too lazy to check) to compare and contrast with the LT1028. When I used the LT1115 (DIP) in my SVDAC05, I thought it sounded fine.


----------



## ecclesand

I also enjoy the LT1028, but I have them in the DIP8 version...the LT1028ACN8. I don't like the clumsy BD adapter I have to use so last night I bought some LT1028CS8 in the SOIC package. I'm looking forward to their arrival.


----------



## SpudHarris

Quote:


  Originally Posted by *Apocalypsee* /img/forum/go_quote.gif 
_I wonder if there is any opamp that have the detail like LT1677 and great vocal and soundstage of LT1363? Maybe I should try AD744 or AD797 next?_

 

I like the AD744's but they are renouned for their hiss which can be very bad when using head/earphones as opposed to speakers. The AD797's in the right circuit I think are one of the finest Opamps (3rd or 4th on my list of favourites).

 I have been listening to the LT1677's on and off nearly all day whilst out and about and I have to say they are growing on me (or burning in 
	

	
	
		
		

		
			





). They are way different to the 1363's but in a good way. Man I love this hobby (today at least 
	

	
	
		
		

		
		
	


	




)


----------



## leeperry

vocals stink on the 1678...the 1364 magic is just gone.

 and I'm still undecided on what buffer to use, I'll grab a chance w/ the 2604 I think.


----------



## leeperry

your screen names are getting worse and worse...running out of imagination after 5000 banned handles? 
	

	
	
		
		

		
		
	


	




 yes, my last try will be the LT1028CS8...then I'll be happy ever after w/ the 1364 
	

	
	
		
		

		
		
	


	




 hummmm OPA2604AP/OPA2277 are too bright as a buffer, it doesn't increase the mid-bass response of the 1364...the OPA2111KP was awesome on that point, but the mids were a bit too recessed....time to try the OPA2132P I think, I don't have too much faith in the OPA211/OPA132U.


----------



## leeperry

ahhhhh 2132P is good stuff! Lucifer-X, try two of these + two LT1364 on your Claro Halo...this should do nicely: the 1364 gives killer vocals and natural SS, the 2132P gives very grainy mids and fantastic bass response.

 ppl who say that the OPA132U is an improvement over the 2132P leave me kinda puzzled 
	

	
	
		
		

		
		
	


	




 maybe I'll try the OPA132U/2604 tomorrow just to clear things up...but godd*** the bass on the 2132P is CRAZY 
	

	
	
		
		

		
		
	


	




 the 2132P seems to give even more depth to the 1364 vocals..I'm stunned! "Bebel Gilberto - O Caminho.flac" really gave me goose bumps 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I also enjoy the LT1028_

 

how are vocals on the 1028? as amazing as on the 1364


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I like the AD744's but they are renouned for their hiss which can be very bad when using head/earphones as opposed to speakers. The AD797's in the right circuit I think are one of the finest Opamps (3rd or 4th on my list of favourites).

 I have been listening to the LT1677's on and off nearly all day whilst out and about and I have to say they are growing on me (or burning in 
	

	
	
		
		

		
		
	


	




). They are way different to the 1363's but in a good way. Man I love this hobby (today at least 
	

	
	
		
		

		
		
	


	




)_

 

Yes, the AD's seem to be very good for audio. I have a 8620,AD8599 and a AD797 and they are all excellent opamps for audio. Seems many around here suggest the AD797 for audio use though, it seems to be a favorite among many of the opamps swappers here. 
 I have been considering trying the LT1677 and coupel others from other manufacturers. 
 New month brings a new build and new modules and chips for me to build and test.


----------



## leeperry

the 2132P really matches w/ all the descriptions of discrete op-amps you can read on the web....it digs so damn deep to find details, it sounds very warm and so damn "organic", a far cry from that 4562 POS...yet many ppl on french forums say that the 4562 outshines the 2132P, they've prolly been impressed by its whiney trebles....this won't last 
	

	
	
		
		

		
		
	


	




 anyway, it makes for a fantastic buffer


----------



## Slash47

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Yes, the AD's seem to be very good for audio. I have a 8620,AD8599 and a AD797 and they are all excellent opamps for audio. Seems many around here suggest the AD797 for audio use though, it seems to be a favorite among many of the opamps swappers here. 
 I have been considering trying the LT1677 and coupel others from other manufacturers. 
 New month brings a new build and new modules and chips for me to build and test._

 

Scrap AD8620, add AD8066 and I agree 100% 
	

	
	
		
		

		
		
	


	




 AD797BRZ, LT1028ACN8, AD8599/AD8066 (because they're duals) top 3 for audio maybe? With LT136x (active buffer/filter) and OPA627BP (for PPA, M3, etc) at 4 and 5? The first two are a bit fussy though, but so is everything that's good.


----------



## Slash47

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_the 2132P really matches w/ all the descriptions of discrete op-amps you can read on the web....it digs so damn deep to find details, it sounds very warm and so damn "organic", a far cry from that 4562 POS...yet many ppl on french forums say that the 4562 outshines the 2132P, they've prolly been impressed by its whiney trebles....this won't last 
	

	
	
		
		

		
		
	


	




 anyway, it makes for a fantastic buffer 
	

	
	
		
		

		
		
	


	


_

 

Listen to a Benchmark DAC1 or a Twisted Pear Opus/Buffalo DAC and report back on the LM4562


----------



## leeperry

hehe, yeah, I was running searches on the forum...some ppl call the LM4562 darker than the 2132P 
	

	
	
		
		

		
		
	


	




 some even call the 4562 too dark...huh? the 49720 has always been crazy bright on my soundcards, totally unbearable and unEQ'able.

 well, whatever on the HD2 or the STX/ST the 2132P mids have always stunned me...Andrea has always praised it greatly, I can hear why...until he moved to the OPA132UA.

 I'll try the OPA132U tomorrow, but I don't really expect them to sound as good?! maybe nasty EMI/RFI playing tricks on my browndog?

 anyway, at this point I don't even feel like rolling anymore...the 2132P adds perfectly to the 1364, I get a slightly dark+highly detailed sound...I still rest my case that the 2132P gives you micro-details(in soundstage/voices/drums) other IC's simply hide


----------



## LuciferX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_ahhhhh 2132P is good stuff! Lucifer-X, try two of these + two LT1364 on your Claro Halo...this should do nicely: the 1364 gives killer vocals and natural SS, the 2132P gives very grainy mids and fantastic bass response.

 ppl who say that the OPA132U is an improvement over the 2132P leave me kinda puzzled 
	

	
	
		
		

		
		
	


	




 maybe I'll try the OPA132U/2604 tomorrow just to clear things up...but godd*** the bass on the 2132P is CRAZY 
	

	
	
		
		

		
		
	


	




 the 2132P seems to give even more depth to the 1364 vocals..I'm stunned! "Bebel Gilberto - O Caminho.flac" really gave me goose bumps 
	

	
	
		
		

		
		
	


	




 how are vocals on the 1028? as amazing as on the 1364 
	

	
	
		
		

		
		
	


	


_

 

Good to know! If someday LT send me 1364 samples i will try it!

 PD: Noob question, the claro halo use 4 opamps for front an HP out:






 Options:

 U8-U10: 2xOPA2132P - U9-U11: 2xLT1364
 U8-U10: 2xLT1364 - U9-U11: 2xOPA2132P

 Advices?

 For now Im still using 4x4580, I have OPA2132P, LM4562NA, LME49860NA and LME49720NA, i need time to start rolling


----------



## leeperry

try both. anyway, I'm really blown away by how these chips sound together on my AK4396 board...this cannot be real, I must be dreaming...must not fall asleep 
	

	
	
		
		

		
		
	


	




 it takes the good sides of both 1364/2132 and blends them seamlessly...I wish I could stack op-amps even further...at this point it does: 2*1364 as LPF > 1*2132 as buffer(to reach line-out level) > 1*JRC4580 high gain to drive my phones(increases the bass control)...makes me drool about discrete op-amps, it seems that the more IC's you stack, the more organic/natural the sound gets...you just need to pick them very carefully(as burson does) 
	

	
	
		
		

		
		
	


	




 it even makes mp3 fully enjoyable, something I didn't think would ever be possible


----------



## Pluto2

Hi Slash47,

 Seems AD797 is not quite unity gain stable, would you think it's stable for gain of 1.5x?

 The reason why LT136x are good for (active buffers/filtrers), becauser of their capacitive loading capability? Plrease share your thoughts : )


----------



## leeperry

hah, even my messages are being deleted now...

 anyone who likes the 136x vocals and tried the 1028, are they as good? coz the 1678 lacks in that department.

 ok time to roll the OPA132U as buffer


----------



## ROBSCIX

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_Scrap AD8620, add AD8066 and I agree 100% 
	

	
	
		
		

		
		
	


	




 AD797BRZ, LT1028ACN8, AD8599/AD8066 (because they're duals) top 3 for audio maybe? With LT136x (active buffer/filter) and OPA627BP (for PPA, M3, etc) at 4 and 5? The first two are a bit fussy though, but so is everything that's good._

 

People seem to have varying opinion on the AD8620. I like it based on my tests. I haveyet to try the AD8066 although I probably have it on a list...

 What do you think of the 627 and 637?

 I have been considering making a match set for I/V tasks.


----------



## Slash47

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_People seem to have varying opinion on the AD8620. I like it based on my tests. I haveyet to try the AD8066 although I probably have it on a list...

 What do you think of the 627 and 637?

 I have been considering making a match set for I/V tasks._

 

I've just finished a modular PPA/M3 clone using AD8065 and it definitely isn't worse then the OPA627 while costing 10x less. Better detail, flatter frequency response. Just not as tubey, it won't please solid state skeptics.

 The OPA637 has better 'thrust' to the sound, a transient really drives home. It 'lets go' a bit better then the OPA627BP and even more so then the other OPA627's. You really need a gain of 10 for it though. And in contradiction to what I just said, it's just as good as the OPA627BP sq wise.

 High source impedance I/V (or voltage upping for driving headphones where the sound goes through a pot) = OPA627BP/637 or AD8065 (or OPA2604). If you have low source impedance or you're designing a circuit with I/V, you might as well go with the LT1028/AD797 or even AD8599 which are all more even and detailed and will introduce less noise.

 Seeing as you like OPA2107 and AD8620, I say you have tacky taste 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Hi Slash47,

 Seems AD797 is not quite unity gain stable, would you think it's stable for gain of 1.5x?

 The reason why LT136x are good for (active buffers/filtrers), becauser of their capacitive loading capability? Plrease share your thoughts : )_

 

The LT1364 seems nice for delta sigma DAC filters and low impedance headphones because of it's massive slew rate and low distortion at low gain and the fact that it's a LOT less fussy then most when it comes to what it's driving and what it needs to stuff it through (as can be read on the specsheet).

 Wether the AD797 would work at 1.5: Yes, it might, but don't bother because it will probably oscillate like hell. Just pick up a AD8597 or 99, it will work a lot better and give a similar sort of sound if treated well.


----------



## leeperry

humm, indeed the OPA132U sounds airier/less bloated than the 2132P 
	

	
	
		
		

		
			





 the bass was really over the top on the 2132P, now the sound is a lot more balanced....makes me even more eager to try the LT1363!

 now are all the crazy details in the mids from the 2132P still there on the 132U? time will tell, but it would sure sound like it 
	

	
	
		
		

		
		
	


	




 PS: hah, I miss the crazy bass of the 2132P already...


----------



## Apocalypsee

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_The LT1364 seems nice for delta sigma DAC filters and low impedance headphones because of it's massive slew rate and low distortion at low gain and the fact that it's a LOT less fussy then most when it comes to what it's driving and what it needs to stuff it through (as can be read on the specsheet)._

 

Hey slash, indeed you are right about LT136X, I used LT1363 as active filters on CS4398 and it works like a charm. Is there any other opamp recommendation for active filter application?


----------



## leeperry

humm the organic magic of the 2132P is not there anymore in the OPA132U...blues guitars were sounding like instant goose bump material, now they sound dull


----------



## Slash47

Quote:


  Originally Posted by *Apocalypsee* /img/forum/go_quote.gif 
_Hey slash, indeed you are right about LT136X, I used LT1363 as active filters on CS4398 and it works like a charm. Is there any other opamp recommendation for active filter application?_

 

You could try LM6171's.


----------



## ROBSCIX

@Slash47:
 I also like many others. Are you being a troll on purpose?


----------



## Slash47

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_@Slash47:
 I also like many others. Are you being a troll on purpose?_

 

I did the wink smiley didn't I?


----------



## ROBSCIX

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_I did the wink smiley didn't I?_

 

I like some of the same opamps you like so I guess we both have tacky taste


----------



## Apocalypsee

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_You could try LM6171's._

 

Hey thanks! Any comment about how LM6171 sounds like? 

 The slew rate is 3x higher than LT1363 and 30MHz more gain bandwidth, but what matter is the price is reasonable in Malaysia 
	

	
	
		
		

		
		
	


	




 I'll buy them soon


----------



## leeperry

wow there's a truckload of difference between OPA2132P/2134P...2134P sounds like OPA132U basically 
	

	
	
		
		

		
		
	


	




 such a far cry from the 2132P, OTOH it's like 5x cheaper..still undecided whether I should try OPA2107AP.


----------



## 12Bass

So, how does OPA2134 sound compared to OPA2132? Although some have said they sound basically the same, I found that OPA2132 had a little more detail on top and might have been a bit more natural. Don't recall much difference in the lows. I could live with the OPA2132 in some circuits, although it is a bit too dark/veiled for my taste. Found the OPA2134 a bit odd... sort of "phasey" in the highs.


----------



## leeperry

I'll do a recap of my tests as buffer later today, right now I'm testing the 2107AP...it sounds seriously good 
	

	
	
		
		

		
		
	


	




 beats all the other TI chips I've tried today so far, but still a far cry from the grainy 2132P mids...but the magic is almost there, it would do wonders on bassy cans if you like a neutral sound I think.


----------



## 12Bass

You prefer OPA2107 to OPA211/2211A? Not me. What application?


----------



## leeperry

I didn't try the 211 as buffer, but it didn't impress me as AK4396 ±9V LPF...very similar to OPA132U, nice and all..but doesn't have the magic organic mids of the 2132P.

 I like the 2107AP, the sound is very natural, SS is great...but no synergy w/ the LT1364, I need an op-amp to increase the mid bass of the 1364 used as LPF, before going to the high gain JRC4580 used to drive headphones(amplifies the bass control)

 EDIT: ahhhhhhhh the 2111KP makes the blues guitars cry again, it's like a 2132P w/o the subwoofer bass. it's gonna be a tie between these 2


----------



## leeperry

so as a ±9V buffer on my AK4396 board between the LT1364 ±9V LPF and the high gain JRC4580(improves the bass control) to drive my cd1k...I tried them all on the same afternoon so my memory wouldn't betray me:

 OPA2277 = too bright!
 OPA2604 = too bright!
 LME49722MA = so bright it made my ears bleed 
	

	
	
		
		

		
		
	


	



 OPA2132P = surreal 3D sound, very very detailed/grainy mids..very wide SS, amazing low/mid bass response. fantastic chip! perfect synergy w/ the LT1364 vocals, each song is like a whole new experience in its own right 
	

	
	
		
		

		
		
	


	



 OPA2111KP = like the 2132P, w/o the organic mids...still less fatiguing and the upper spectrum is more neutral/recessed. SS is narrower too.
 2*OPA132U = too neutral, pointless...PRAT is low.
 OPA2134P = same sound as OPA132U IMO...I wouldn't be able to identify them in a DBT.
 OPA2107 = great SS, not enough mid bass but low end bass is great. very natural, but too polite to my taste.

 now I'm waiting to try 4*1028/1363/1677 to replace the 2*1364 LPF, then rolling will be over(2132P stays!)...but there's no hurry tbh 
	

	
	
		
		

		
		
	


	




 the OPA2132P was already a winner as a ±12V PCM1792A I/V on the Asus STX/ST, the mids are just super super grainy...it gives a very impressive SQ, mixed w/ the LT1364 vocals it just tops all my expectations
	

	
	
		
		

		
		
	


	




*PS:* for instance the low end bass line of "Nick Cave - Red Right Hand.flac" is hard to retranscribe, this combo plays it loud and clear.


----------



## LuciferX

You are testing using HP or Line out? What speakers/HP and what configuration for them are you using? (I have the Claro Halo with AKGs K701 so i need some references)


----------



## leeperry

HP out > cd1k(same drivers as cd3k, just wider SS and less bassy)

 for classical music, I'd put the 2111KP...but it doesn't make the blues guitars cry enough to my taste.


----------



## leeperry

one thing's that's really pathetic is when you see ppl wasting half a grand(or more!) on a cryo cable blabla blessed by whatever shaman up in the hills(and then plug it to an ipod 
	

	
	
		
		

		
			





)....when a simple $7 op-amp roll will give you FAR more definition/SS improvements than any recabling ever will...classical music(especially violins) sounds so amazing on the 2132P


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_So, how does OPA2134 sound compared to OPA2132? Although some have said they sound basically the same, I found that OPA2132 had a little more detail on top and might have been a bit more natural. Don't recall much difference in the lows. I could live with the OPA2132 in some circuits, although it is a bit too dark/veiled for my taste. Found the OPA2134 a bit odd... sort of "phasey" in the highs._

 

Personally, I found the 2132 a bit boring as you said just dark,veiled..nothing special. -Some like that type of soudn depending on gear.
 The 2134 is not bad but again there are better units based on personal taste. The 2134 seems to be widely recommend as a "gereric" audio opamp. Although I find it can offer improvements over other generics,


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_You prefer OPA2107 to OPA211/2211A? Not me. What application?_

 

I would also take the 211 over the OPA2107 although the 2107 can produce some great sound also depending on the circuit application.


----------



## ecclesand

After screwing around with the various LT opamps, I finally settled down and after about 40 hours of burn-in on the dual LME49710HA module I built, did a comparison to the single LME49720HA module. I don't know if it's placebo or not, but I did find that the 2 LME49710HAs sounded better than the LME49720HA. Both modules had at least 40 hours on them. The 49710s sounded more dynamic to my ears as line out drivers for my PCM1793 Peridot DAC. If it is placebo, then so be it...I can live with that.
	

	
	
		
		

		
		
	


	




 I do find that the LME opamps...after adequate burn-in...yield a more consistent and balanced sound. I am very impressed with the soundstage and the smooth mids. No harshness in the upper regions either. Just the right amount of sparkle. The bass is deep, but doesn't overpower the other frequency ranges.

 I think I will give the obsessive rolling a rest for a while and simply concentrate on burning in the various modules I have. Once done with that, then I can do a more useful (at least to me) comparison. Plus, I have a used Lite Dac-AH coming in that I plan to mod based on the various threads here. That should adequately take my mind off rolling opamps for a while. Of course, if I keep the active output of the Dac-AH, I'll have more opamps to roll.


----------



## FallenAngel

Yeah, LME49720 is nice as line driver. AD744 compensation output anyone?


----------



## leeperry

it's funny how different applications/voltages yield different results...anyone cares to swap these 497x0HA for a OPA2132P and post his impressions as a buffer?

 I have yet to find an op-amp giving such surreal ultra-detailed mids, it seems to add a new super-wide SS of its own digging for hidden stuff within the side channels...some sort of fourth dimension or something, you don't just hear the sound you get to live it 
	

	
	
		
		

		
		
	


	




 it gave me the same exact impression as I/V on the STX/ST or as line buffer on the HD2...it's the exact sound I'm imagining a burson would give....thinking that a burson would give an even more organic flowing sound is scary actually! too bad they require a cap and some soldering, otherwise I'd be willing to try one...but I like PNP stuff 
	

	
	
		
		

		
		
	


	




 IIRC 2132P was Andrea's favorite a little while ago


----------



## levin

just rolled with HDAM Moon in DAC and 2 LME49720 and i have to say i am quite impressed when i am listening to it with a AKG K702. the huge soundstage really match each other quite well.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_After screwing around with the various LT opamps, I finally settled down and after about 40 hours of burn-in on the dual LME49710HA module I built, did a comparison to the single LME49720HA module. I don't know if it's placebo or not, but I did find that the 2 LME49710HAs sounded better than the LME49720HA. Both modules had at least 40 hours on them. The 49710s sounded more dynamic to my ears as line out drivers for my PCM1793 Peridot DAC. If it is placebo, then so be it...I can live with that.
	

	
	
		
		

		
		
	


	


_

 

Your not alone in that thought. I also think the dual module sounds better then the single dual chip and there are two or three other members on Head-fi that performed similar tests and take the Dual LME49710 module over the single dual channel 720HA. All that I have talked to that have done the similar testing reports very similar results.
  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I do find that the LME opamps...after adequate burn-in...yield a more consistent and balanced sound. I am very impressed with the soundstage and the smooth mids. No harshness in the upper regions either. Just the right amount of sparkle. The bass is deep, but doesn't overpower the other frequency ranges._

 

Yes, they are a excellent module for audio use.
  Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I think I will give the obsessive rolling a rest for a while and simply concentrate on burning in the various modules I have. Once done with that, then I can do a more useful (at least to me) comparison. Plus, I have a used Lite Dac-AH coming in that I plan to mod based on the various threads here. That should adequately take my mind off rolling opamps for a while. Of course, if I keep the active output of the Dac-AH, I'll have more opamps to roll.
	

	
	
		
		

		
		
	


	


_

 

That is usually a good idea. Taking the time to sit and enjoy the opamps instead of constantly comparing them.


----------



## leeperry

so you guys are too scared to hate the 497x0HA resonances afterwards to try replacing it w/ an OPA2132P for a few mins? 
	

	
	
		
		

		
		
	


	




 but well, it also comes down to your cans....I really don't like the 1364+2132 combo on my stock cd3k, when OTOH it gives a totally enveloping 3D sound on my modded cd1k(same drivers as cd3k, less bloated bass, clearer trebles, wider SS).....so indeed, it's pretty much impossible to choose op-amps from a datasheet


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_so you guys are too scared to hate the 497x0HA resonances afterwards to try replacing it w/ an OPA2132P for a few mins? 
	

	
	
		
		

		
		
	


	




 but well, it also comes down to your cans....I really don't like the 1364+2132 combo on my stock cd3k, when OTOH it gives a totally enveloping 3D sound on my modded cd1k(same drivers as cd3k, less bloated bass, clearer trebles, wider SS).....so indeed, it's pretty much impossible to choose op-amps from a datasheet 
	

	
	
		
		

		
		
	


	


_

 

I've already tried the OPA2132P and OPA2132PA. I like them very much but feel the LMEs are better.


----------



## leeperry

any diff between OPA2132P/OPA2132PA? but well, higher grades always seem to sound better for audio.

 I'm quite sure you would hate the resonances of the 49720HA after rolling the 2132P for a while...it's just got those magic grainy mids and a surreal(yes perfectly natural) SS, totally amazing 
	

	
	
		
		

		
		
	


	




 to me the 49720HA cuts the SS in way too many slices, hence SS is artificial to death...and the trebles hahahahaha


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I've already tried the OPA2132P and OPA2132PA. I like them very much but feel the LMEs are better._

 

I have also tested out the 2132's and find they are nothing special and I prefer the LME49720 over them and easily prefer the LME49710HA over it.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I've already tried the OPA2132P and OPA2132PA. I like them very much but feel the LMEs are better._

 

Have you tried the class A procedure with this module?
 How about a Pic of the LME49710HA module?


----------



## ecclesand

I posted the monstrosity a few days ago...

http://www.head-fi.org/forums/f6/opa...ml#post6054301

 I haven't tried the Class A with any modules in the past several days.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I posted the monstrosity a few days ago...

http://www.head-fi.org/forums/f6/opa...ml#post6054301

 I haven't tried the Class A with any modules in the past several days._

 

Sorry must have missed that. Must have to do with the pages of garbage being posted one after another. 
 I figured you had a dual To-99 adapter. I guess that would work also for testing. Post your impressions if you try class A on this unit.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Sorry must have missed that. Must have to do with the pages of garbage being posted one after another. 
 I figured you had a dual To-99 adapter. I guess that would work also for testing. Post your impressions if you try class A on this unit._

 

The kids aren't home from school yet and I'm done with work for the day so I decided to class A the 49710HA module. Forgive the crappy mounting, but it was my only option considering the opamps were already mounted on the adapter.







 They get very warm, I can hold my finger on top of each can for about 5 seconds. The max temp for these is 85 degrees Celsius so who knows. They do sound livelier than the non biased module.

 EDIT: The resistors are both 2.2k. I believe one is rated at 1/2W and the other at 1/4W. I only had one of each left. The bottom end is definitely tighter with the biasing...very snappy. Someone else should try this to see how much heat they get from these.


----------



## leeperry

Quote:


  Originally Posted by *extraordinary machine* /img/forum/go_quote.gif 
_BTW the OPA2132P is very decent... but I would go with 2x OPA132UA which sound veeery good. 
	

	
	
		
		

		
		
	


	


_

 

considering how the 2134P is a major downgrade compared to the 2132P, I've got a hard time believing that 2*OPA132UA would sound better than 2*OPA132U(that totally lack the great bass response of the 2132P) 
	

	
	
		
		

		
		
	


	




 it seems that bass is very hard to output for an op-amp(compare the 49720NA w/ his inexistent low end bass to the 49720HA where it's overwhelming)....maybe the DIP package actually shields some EMI/RFI the browdog's simply don't 
	

	
	
		
		

		
		
	


	




 anyway the "magic" mids of the 2132P were very audible to me whatever on the DT770/600Ω and the STX/ST or the cd1k on the HD2...so it wouldn't appear to be that much environment dependent.

 my hopes towards browndog's are very low, I'll try the 4*1363/1028 to replace my 2*1364 LPF...but from what Slash47 said my best option would be to replace the 2132P buffer by a burson. a burson is 50 EUR basically(and I already have fully gold plated DIP8 sockets), not too pricey 
	

	
	
		
		

		
		
	


	



*PS:* maybe I'll try to replace the 2132P by the 2111KP, this one was less impressive but more balanced..and still a bit magic


----------



## ROBSCIX

Quote:


  Originally Posted by *extraordinary machine* /img/forum/go_quote.gif 
_I can't see why you keep overlooking the LME49723. It's the sweet spot - for me - between the different deviations (from transparency) of the various LME49720NA, LME49860NA, LM4562NA.

 Maybe because it's priced at $ 0.70. 
	

	
	
		
		

		
		
	


	




 The LME49720HA does sound a bit more dynamic and smoother, but... well I need to compare directly. I have the feeling that it'll be interesting..._

 

Have you tried a dual LME49710HA module yet?


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_The kids aren't home from school yet and I'm done with work for the day so I decided to class A the 49710HA module. Forgive the crappy mounting, but it was my only option considering the opamps were already mounted on the adapter.

 They get very warm, I can hold my finger on top of each can for about 5 seconds. The max temp for these is 85 degrees Celsius so who knows. They do sound livelier than the non biased module.

 EDIT: The resistors are both 2.2k. I believe one is rated at 1/2W and the other at 1/4W. I only had one of each left. The bottom end is definitely tighter with the biasing...very snappy. Someone else should try this to see how much heat they get from these._

 

I may try it here soon but I am in the process of ordering a bunch of new parts for my parts bin so I will have to wait until I put in the next order.
 I have been considering checking this out to hear the difference.
 Thx for the info...


----------



## levin

is there a compliation of list of opamps people are using? would be nice if there was a breakdown of different companies opamp numbers and etc.


----------



## SpudHarris

Quote:


  Originally Posted by *extraordinary machine* /img/forum/go_quote.gif 
_DON'T DO THAT! What? You want to make the LME49710HA even smoother? 
	

	
	
		
		

		
		
	


	




 Really, this is one of all those modern opamps for which that trick does only harm...

 Plus you completely screwed up the resistor value._

 

What resister value then? I've always used 2.2k as that's what Ron kerlin (Hiflight) told me to use. FWIW I don't get too much heat from mine in my P3+ headphone amp. Set up is different as I have 2 x single sockets so use 2 x 49710's in Class A adapters.


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_What resister value then? I've always used 2.2k as that's what Ron kerlin (Hiflight) told me to use. FWIW I don't get too much heat from mine in my P3+ headphone amp. Set up is different as I have 2 x single sockets so use 2 x 49710's in Class A adapters._

 

I got my Lite DAC-AH yesterday and modded it by replacing some resistors, adjusting vref, and adding opamp sockets for rolling. I want to play with opamps before going to a passive output. Luckily the output stage consists of 2 single channel opamps. I'm currently waiting on some OPA627s. I will order some more LME49710HAs and bias them to class A but on single adapters and then test them on the Lite. On the module in the picture, I added a copper heatsink to the 2 49710s using some 3M thermal tape and it's working quite nicely.

 By the way, this DAC-AH sounds very good modded. I'm running it with two LT1357s until the 627s arrive.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I got my Lite DAC-AH yesterday and modded it by replacing some resistors, adjusting vref, and adding opamp sockets for rolling. I want to play with opamps before going to a passive output. Luckily the output stage consists of 2 single channel opamps. I'm currently waiting on some OPA627s. I will order some more LME49710HAs and bias them to class A but on single adapters and then test them on the Lite. On the module in the picture, I added a copper heatsink to the 2 49710s using some 3M thermal tape and it's working quite nicely.

 By the way, this DAC-AH sounds very good modded. I'm running it with two LT1357s until the 627s arrive._

 

So both you and Spudharris are using them in class A config?
 I like the 627's and I am considering building a matched pair of TO-99's for both the 627's and 637's. I wonder if the extra heat is because of the dual config or if there is extra heat when using in single channel module also. Will have to ask.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_What resister value then? I've always used 2.2k as that's what Ron kerlin (Hiflight) told me to use. FWIW I don't get too much heat from mine in my P3+ headphone amp. Set up is different as I have 2 x single sockets so use 2 x 49710's in Class A adapters._

 

Your using the LME49710HA in a single channel circuit and the heat is acceptable? I know the class A bias would generally produce more heat and all opamps produce heat anyway. 
 The questions is, is this heat from normal operation or is there some other issue?
 Your using them baised to class A in a single channel circuit position and you say the heat is not too excessive.
 Ecclesand, is using a dual channel module biased to class A and says there is quite a bit of heat.
 Just wondering if the heat is from the dual channel module. I am going to have to do some testing....


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Your using the LME49710HA in a single channel circuit and the heat is acceptable? I know the class A bias would generally produce more heat and all opamps produce heat anyway. 
 The questions is, is this heat from normal operation or is there some other issue?
 Your using them baised to class A in a single channel circuit position and you say the heat is not too excessive.
 Ecclesand, is using a dual channel module biased to class A and says there is quite a bit of heat.
 Just wondering if the heat is from the dual channel module. I am going to have to do some testing...._

 

I don't have any dual channel converters like that one as my P3, P3+ and my PPA are all single channel sockets. Unfortunately I only have one OPA627 which was ground in my PPA, I have 4 x 637's but they are unstable in my favourite amp (P3+). Nothing gets overly hot with Class A chips in my P3+.

 Started listening to the Ultimae Fahrenheit Project Collection last night and rolled some Opamps to suit this Genre (Ambient Trance), the LT1028's are all over this genre and then some


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I don't have any dual channel converters like that one as my P3, P3+ and my PPA are all single channel sockets. Unfortunately I only have one OPA627 which was ground in my PPA, I have 4 x 637's but they are unstable in my favourite amp (P3+). Nothing gets overly hot with Class A chips in my P3+.

 Started listening to the Ultimae Fahrenheit Project Collection last night and rolled some Opamps to suit this Genre (Ambient Trance), the LT1028's are all over this genre and then some 
	

	
	
		
		

		
		
	


	


_

 

The 637 don't have internal compensation so they need fairly high circuit gain to operate properly. They are one of my favorites and I am considering building matched sets of both 627 and 637 TO-99 modules.
 So if you don't notice any excess heat in single channle circuit perhaps the issue is the dual channel module. Really though, looking at it as a circuit; the only thing that is shared between the two LMR49710HA chips is the power and gnd rails.
 Maybe it is not the biasing and is something else.
 I have the LT1028's on my list of opamps to test.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I got my Lite DAC-AH yesterday and modded it by replacing some resistors, adjusting vref, and adding opamp sockets for rolling. I want to play with opamps before going to a passive output. Luckily the output stage consists of 2 single channel opamps. I'm currently waiting on some OPA627s. I will order some more LME49710HAs and bias them to class A but on single adapters and then test them on the Lite. On the module in the picture, I added a copper heatsink to the 2 49710s using some 3M thermal tape and it's working quite nicely.

 By the way, this DAC-AH sounds very good modded. I'm running it with two LT1357s until the 627s arrive._

 

When you tested the LME49710HA module without the biasing, did you notice any excess heat?


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_rolled some Opamps to suit this Genre (Ambient Trance), the LT1028's are all over this genre and then some_

 

any chance for a 1028<>1364 shootoot for vocals? the 1678 stinks compared to the 1364 on that point..


----------



## lu-chen-chan

Hello in the future i will certainly buy ibasso D10 to my Livewires , and i will want to switch OPA, to make sound more warm and bassy , can you advice me some good OPAs?


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_When you tested the LME49710HA module without the biasing, did you notice any excess heat?_

 

Nope. It was definitely the addition of the resistors that caused the increased heat. I wish I had a thermal gun to check the actual temperature. I'm sure it's well within tolerances, but I'm just curious. In any case, the addition of the heatsink has dramatically cooled them down.

 Like someone already mentioned...perhaps using the LME49710 in my circuit was already borderline and adding the resistance pushed them over the edge.


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_any chance for a 1028<>1364 shootoot for vocals? the 1678 stinks compared to the 1364 on that point.._

 

Well there's no real vocals in the Ultimae stuff, only samples that aren't supposed to draw you in. I only use the 1363's but have to say that nothing touches them in my books for vocals, so natural so silky smooth and so real. Try the 1363's with something like Lifehouse and you feel every single drop of emotion, just mint!! The 1028's pip the 1364's for this Genre and specifically Ultimae stuff because the resolution seems better and really brings out the spacy feel to the compositions.


----------



## SpudHarris

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Nope. It was definitely the addition of the resistors that caused the increased heat. I wish I had a thermal gun to check the actual temperature. I'm sure it's well within tolerances, but I'm just curious. In any case, the addition of the heatsink has dramatically cooled them down.

 Like someone already mentioned...perhaps using the LME49710 in my circuit was already borderline and adding the resistance pushed them over the edge._

 

I'm curious also as mine are only luke warm. I want to know mine are working as hard as hell 
	

	
	
		
		

		
			





. What pins did you short out on those TO-99's?


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I'm curious also as mine are only luke warm. I want to know mine are working as hard as hell 
	

	
	
		
		

		
		
	


	




. What pins did you short out on those TO-99's?_

 

I did 4 (V-) and 6 (Out). I had heat issues with the other biasing I did shorting pin 7 (V+) and 6 (Out). I can't win.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I only use the 1363's but have to say that nothing touches them in my books for vocals, so natural so silky smooth and so real. Try the 1363's with something like Lifehouse and you feel every single drop of emotion, just mint!!_

 

fully agreed, I don't really see how you could top the 1364 for vocals..their super natural sound mixed w/ the 2132P surreal mids/SS is just instant eargasm material 
	

	
	
		
		

		
		
	


	




 I know cable detractors like to complain that if you can't measure it...you can't improve it, but wth do these chips do that is so magic 
	

	
	
		
		

		
		
	


	




 ah well, I guess there's no way in hell to quantify the SQ of op-amps...uber-low THD like the 49722MA clearly doesn't equal better PRAT. 

*PRAT can't be measured* ..that's the bottom line I guess


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well there's no real vocals in the Ultimae stuff, only samples that aren't supposed to draw you in. I only use the 1363's but have to say that nothing touches them in my books for vocals, so natural so silky smooth and so real. Try the 1363's with something like Lifehouse and you feel every single drop of emotion, just mint!! The 1028's pip the 1364's for this Genre and specifically Ultimae stuff because the resolution seems better and really brings out the spacy feel to the compositions._

 

I wonder if there are metal can version of the LT1363's? You seem to like them so that would bw a possible further upgrade for you.
 Have you considered this route?


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I wonder if there are metal can version of the LT1363's? You seem to like them so that would bw a possible further upgrade for you.
 Have you considered this route?_

 

I would definately consider that but don't recall seeing them on Farnell. Il have to have a look.

 Hey Doug, I posted a pic on Beard-fi - Check me out baby!! Get growing


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I would definately consider that but don't recall seeing them on Farnell. Il have to have a look.

 Hey Doug, I posted a pic on Beard-fi - Check me out baby!! Get growing 
	

	
	
		
		

		
		
	


	


_

 

Ditto...from a while ago, though. Maintaining a beard is such a PITA so I let it go for a few days and then shave. Repeat.

 I'm going to go on a single opamp buying spree...I think I only have 3 sets that I can use.


----------



## SpudHarris

Haha nice one, another Goatee lover 
	

	
	
		
		

		
		
	


	




 you are a handsome devil!

 I do have a few dual Opamps as the P3 and P3+ accept both in L/R positions and I make and sell a few cmoys here and there so have to keep a few in stock. I really like to squeeze every last bit of SQ out of my Opamps and singles are just easy to pop into a pre-made CA Adapter.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I would definately consider that but don't recall seeing them on Farnell. Il have to have a look.



_

 

You may not be able to find them through local channels but they may still be available. I have a couple guys that source parts for me in ASIA and they can find almost anything... I will have a look and see what I can find.


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_You may not be able to find them through local channels but they may still be available. I have a couple guys that source parts for me in ASIA and they can find almost anything... I will have a look and see what I can find._

 

Thanks Rob, 
 when you say 'may still be available' it makes me think 'expensive'. If you can track them down let us know


----------



## jhanby

Hi Guys,
 Am looking into building my first Cmoy amp.

 Im having troubles finding the recommend Opamps though.
 According to this website, it recommends using the OPA132. 
 However, the only place I can find this opamp is RS components, which I cannot buy from.

 Can anyone show me where they buy their Opamps from (in UK) or offer an alternative Opamp. ?

 Im in the UK.

 John


----------



## SpudHarris

Hi John,

 the OPA132 is available from Farnell. You do know it's a single channel Opamp don't you. Are you doing the Cmoy with proto board or PCB? cuz I still have some JDS labs Cmoy boards (bass boost option).

 Oh I'm also in the UK, where abouts are you?

 Nigel


----------



## jhanby

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Hi John,

 the OPA132 is available from Farnell. You do know it's a single channel Opamp don't you. Are you doing the Cmoy with proto board or PCB? cuz I still have some JDS labs Cmoy boards (bass boost option).

 Oh I'm also in the UK, where abouts are you?

 Nigel_

 

Hi,
 No i did not know that it was a single channel.

 What would you recommend instead ?

 I may be planning on using a protoboard, but may be intrested in those PCBs, you got a link to any more details ?

 And i'm in Peterborough
	

	
	
		
		

		
		
	


	




 EDIT : just found this, which looks a bit better ?

 John


----------



## Slash47

That's the one, I'm sure they have a opa2132P (not PA) in stock.

 edit: oh wait, they don't... you can also use 2107 if you're willing to spend a bit more, or a AD823. They all work well and sound as good as the 2132.


----------



## SpudHarris

That's the one to start off with really. What sort of level are you at with the whole cmoy/opamp thing?

 I've been making these for a while now and still got some boards and a few 2132's left I can let you have to get you started if you like. You can have variable bass (50k pot) or a toggle switch for a set bass boost or just bypass it.


----------



## ecclesand

Nice build there, Nigel.


----------



## jhanby

Well this is going to be my first cmoy and my first electronics project really (although I've had quite a bit of experience with electronics in general before.

 I think it may be better for me to use a protoboard, so that I can learn more about the schematic. This project is more for learning to go onto bigger DIY desktop amps really.

 Thanks for the offer and the new website (farnell)


----------



## SpudHarris

Quote:


  Originally Posted by *jhanby* /img/forum/go_quote.gif 
_I think it may be better for me to use a protoboard, so that I can learn more about the schematic._

 

Agreed..........for me? well I'm a lazy ass and still don't know much about even a cmoy circuit
	

	
	
		
		

		
		
	


	




 hehe


----------



## ROBSCIX

Quote:


  Originally Posted by *jhanby* /img/forum/go_quote.gif 
_Hi,
 No i did not know that it was a single channel.

 What would you recommend instead ?

 I may be planning on using a protoboard, but may be intrested in those PCBs, you got a link to any more details ?

 And i'm in Peterborough
	

	
	
		
		

		
		
	


	




 EDIT : just found this, which looks a bit better ?

 John_

 


 Peterborough? ONT or UK?


----------



## SpudHarris

He's in the UK Rob (see his original post).


----------



## ecclesand

I have now tried 2 x LT1363; 2 x LT1028; and 2 x LT1357 as the line drivers of my DAC-AH. Without a doubt...to my ears...the LT1357 sounds the best surprisingly. The LT1363 sounded mushy. The LT1028 sounded harsh in the upper end. The LT1357 must have some synergy with this DAC...wide and natural soundstage, deep punchy bass, smooth mids, and clear highs. I'm still waiting on the opa627s and LME49710HAs.


----------



## SpudHarris

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Nice build there, Nigel.
	

	
	
		
		

		
		
	


	


_

 

Thanks Doug!

 I must get around to a few more builds, there is a lack of guys building/selling these in the UK. E-bay is ripe for a quality but reasonably priced cmoy for the UK market.


----------



## ROBSCIX

@Spud, that is a nice build for a portable amp. Great stuff!

 @Jude, if you like the LME49720HA, I sugegst you test out the LME49710HA as there is a noticable improvement over the dual channel module. This is according to impression reported from quite a few people around here.


----------



## ecclesand

Quote:


  Originally Posted by *hey jude* /img/forum/go_quote.gif 
_That is no synergy matter. It's exactly how the same opamps have sounded for my ears in my extended testing (and my hardware).


 The LT1363 does sound "mushy", except in a CMOY where it's the best I've heard.

 The LT1028 (both ACN8 and CS8) does have an aggressive treble, unfortunately.

 The LT1357 is simply the best opamp of the bunch. I remember how very much better it sounded than a TI NE5534, as well.


 That's no mystery, though... Jim Williams of Audio Upgrades (very popular guy in other forums - not a trace of him here) has been saying that the LT1357 is the best single opamp with the OPA211 for quite some time. He used to work at Linear Technology, if I recall correctly._

 

Hey Andrea...I didn't care for the dual LT1357s in another circuit. Although, they were mounted on a 2 to 1 BD adapter. It sounded OK, but not as good as other LTs. I felt the same about the dual version LT1358. They were just very unimpressive at first. Perhaps the Dac-AH is more resolving than the Peridot.


----------



## Reima

I got my TO-99 dual adapters so I put together a dual LME49710HA module. This module just replaced the LME49720HA that I had in my Pimeta V1, I haven't had a chance to do much listening with it as yet but so far I like what I hear.
 RC


----------



## leeperry

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I didn't care for the dual LT1357s in another circuit. Although, they were mounted on a 2 to 1 BD adapter. It sounded OK, but not as good as other LTs._

 

1357 sounding better than 1364, hell breaks loose 
	

	
	
		
		

		
		
	


	




 maybe I'll try the 1358/1057ACN8 on my current board, but they were whiney/resonant as hell on the STX as I/V...anyway, I think I'm gonna try a new burson to replace the 2132P...or possibly give its chance to the 2111KP, it sounded less V-EQ shaped than the 2132P I think


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_1357 sounding better than 1364, hell breaks loose 
	

	
	
		
		

		
		
	


	




 maybe I'll try the 1358/1057ACN8 on my current board, but they were whiney/resonant as hell on the STX as I/V...anyway, I think I'm gonna try a new burson to replace the 2132P...or possibly give its chance to the 2111KP, it sounded less V-EQ shaped than the 2132P I think 
	

	
	
		
		

		
		
	


	


_

 

I've always rated the 1357's. probably 3-4 on my fave list!


----------



## leeperry

I remember I liked the 1358 as it was my first LT chip, waking up from the 49720HA nightmare....but after a while I found its trebles too digital to my taste, and not involving enough...just dull.

 what's annoying is that you can only fit one op-amp in your cmoy apparently? I couldn't live w/ either the 1364 or the 2132P....but mixed together they seem to only show their good sides(1364 for vocals/natural SS, 2132P for wide natural SS/great bass response/magic mids).

 ah well, I wish I could stack 4-5 op-amps, like adding a burson behind the 1364+2132P...but as Stash47 said 2*1364+1*burson must be the magic combination


----------



## ecclesand

Quote:


  Originally Posted by *Reima* /img/forum/go_quote.gif 
_I got my TO-99 dual adapters so I put together a dual LME49710HA module. This module just replaced the LME49720HA that I had in my Pimeta V1, I haven't had a chance to do much listening with it as yet but so far I like what I hear.
 RC


_

 

Nice job! Beats the hell out of my ghetto job of bending pins and soldering them to a dual DIP8 adapter.


----------



## ROBSCIX

Quote:


  Originally Posted by *Reima* /img/forum/go_quote.gif 
_I got my TO-99 dual adapters so I put together a dual LME49710HA module. This module just replaced the LME49720HA that I had in my Pimeta V1, I haven't had a chance to do much listening with it as yet but so far I like what I hear.
 RC_

 

Post your impressions. I have been using dual LME49710HA's for quite some time. There are quite a few others that are starting to check out this units also and all reports seem positive. The dual single channel modules sound different and arguably better then the single dual channel model. -according to reports.


----------



## leeperry

humm indeed, the OPA2111KP is a lot less V-EQ shaped than the OPA2132P as a buffer...not as impressive but more natural 
	

	
	
		
		

		
			





 this thread's got it all right: http://www.head-fi.org/forums/f5/lit...olling-304261/

 PS: ah well, it's boring...back to 2132P


----------



## xsoundx

what are people using to roll these opamps in?

 Is it mostly Cmoy?


----------



## Apocalypsee

Quote:


  Originally Posted by *xsoundx* /img/forum/go_quote.gif 
_what are people using to roll these opamps in?

 Is it mostly Cmoy?_

 

Nope, it depends. I used it on soundcard, leeperry and ROBSCIX too. Others not quite sure. The opamp is used for active filters on my soundcard


----------



## SpudHarris

Quote:


  Originally Posted by *xsoundx* /img/forum/go_quote.gif 
_what are people using to roll these opamps in?

 Is it mostly Cmoy?_

 

Nah, Ibasso P3+. L/R > Buffers > G/VG


----------



## ROBSCIX

Quote:


  Originally Posted by *xsoundx* /img/forum/go_quote.gif 
_what are people using to roll these opamps in?

 Is it mostly Cmoy?_

 

Most are using different circuits and applications.
 Some are using external units, some soundcards.

 Some circuits just use buffers, other use I/V and or buffer.

 Some are using circuits that have different opamps layouts then what was mentioned.


----------



## Apocalypsee

Oh, forgot to add, I used it for active filters


----------



## ROBSCIX

Quote:


  Originally Posted by *Apocalypsee* /img/forum/go_quote.gif 
_Oh, forgot to add, I used it for active filters_

 


 ..such as?


----------



## Apocalypsee

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_..such as?_

 

No, I meant for my previous post. I used the opamp for active filters on CS4398 DAC on X-Fi Elite Pro. Maybe I should edit my previous post


----------



## ROBSCIX

I just wasn't sure what you meant by active filters, I know what they are but wasn't sure if you had built seperate circuits using opamps..etc..

 Your using the X-fi for filtering another source?


----------



## Apocalypsee

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I just wasn't sure what you meant by active filters, I know what they are but wasn't sure if you had built seperate circuits using opamps..etc..

 Your using the X-fi for filtering another source?_

 

No, I thought you understand that perfectly, the use of that opamp is for signal shaping and filter the out-of-band frequencies on CS4398, read the datasheet, hence the name active filters, I can't use simple RC circuits since it have differential outputs, I used them before but don't sound as good because I only use one of the differential signal from each channel

 Its different from other DAC such as PCM1792A or AK4396 which uses opamp for two purpose, first is for current to voltage converters and second stage as buffers before going to the output, CS4398 is a voltage out DACS so it don't requires a two stage design (I/V + buffer) like both two


----------



## ROBSCIX

Quote:


  Originally Posted by *Apocalypsee* /img/forum/go_quote.gif 
_No, I thought you understand that perfectly, the use of that opamp is for signal shaping and filter the out-of-band frequencies on CS4398, read the datasheet, hence the name active filters, I can't use simple RC circuits since it have differential outputs, I used them before but don't sound as good because I only use one of the differential signal from each channel

 Its different from other DAC such as PCM1792A or AK4396 which uses opamp for two purpose, first is for current to voltage converters and second stage as buffers before going to the output, CS4398 is a voltage out DACS so it don't requires a two stage design (I/V + buffer) like both two_

 

OK. I see what you mean now. Still thought you were refering to something different.
 I have quite a few devices with this DAC and others so I am familiar with DAC filtering etc.
 Had a bit of a mic-communication there...my bad.


----------



## ROBSCIX

Anybody else testing the OPA1611 or 1612?


----------



## qusp

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Anybody else testing the OPA1611 or 1612?_

 

well as you know, I am, they have stayed in my D10, i'm actually using 2 x 1611 in I/V on browndog and 2 x 1612's one for each channel as buffers. they are really great buffers too, the 1611's provide enough drive no problem with dummy buffers, but i'm finding just a bit more authority using with the buffers installed. 

 the 1611 is currently my favorite I/V OPAMP in D10, beats the class A topkit, I broke one of the leads on my last 2 x SOIC8 to DIP8 adapter when installing it with 2 x OPA211, so dont have any comparison to make there until my adapters arrive or I get impatient and desolder something old that i'm not using.

 the 1611 has a non-fatiguing, yet very detailed and balanced presentation with my Jh13. zero hiss and great speed. i'm really enjoying it.


----------



## ROBSCIX

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_well as you know, I am, they have stayed in my D10, i'm actually using 2 x 1611 in I/V on browndog and 2 x 1612's one for each channel as buffers. they are really great buffers too, the 1611's provide enough drive no problem with dummy buffers, but i'm finding just a bit more authority using with the buffers installed. 

 the 1611 is currently my favorite I/V OPAMP in D10, beats the class A topkit, I broke one of the leads on my last 2 x SOIC8 to DIP8 adapter when installing it with 2 x OPA211, so dont have any comparison to make there until my adapters arrive or I get impatient and desolder something old that i'm not using.

 the 1611 has a non-fatiguing, yet very detailed and balanced presentation with my Jh13. zero hiss and great speed. i'm really enjoying it._

 

I like the OPA1611's so far also. I built a matched set for a another circuit but ended up using one for a buffer in a new circuit.
 I have some 1612's but haven't gotten aorund to soldering them up yet.

 Have you considered trying the Class A bias on the 1611 opamp?


----------



## 12Bass

Hmmm.... will have to try OPA1611/12.... curious to find out if they sound different than OPA211/2211A. I like the OPA2211A in my Echo Gina24.


----------



## Apocalypsee

I wanted to buy OPA211 that people been praised about, but the prices are mind boggling, I can buy 5x LM6171 for the price of one OPA211


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Hmmm.... will have to try OPA1611/12.... curious to find out if they sound different than OPA211/2211A. I like the OPA2211A in my Echo Gina24._

 

IIRC, the spec sheets are very similar for both the 211 and the 161X series.
 Perhaps they are just different variations of the same designs.


----------



## ROBSCIX

Quote:


  Originally Posted by *Apocalypsee* /img/forum/go_quote.gif 
_I wanted to buy OPA211 that people been praised about, but the prices are mind boggling, I can buy 5x LM6171 for the price of one OPA211 
	

	
	
		
		

		
		
	


	


_

 

WOW, they are that pricey where you are?
 What about samples?


----------



## qusp

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I like the OPA1611's so far also. I built a matched set for a another circuit but ended up using one for a buffer in a new circuit.
 I have some 1612's but haven't gotten aorund to soldering them up yet.

 Have you considered trying the Class A bias on the 1611 opamp?_

 

indeed they are very nice IMO, i'm doing a class A adapter for the OPA211, so if that works nicely i'll use some of the 1611 as well. was going to save a couple for use in a possible transportable PCM1794A dac i'm thinking about building, so might just stick with 211CA, or make a socketed CA adapter if it will fit in D10 (perhaps bias the socket that is in there somehow, hardwired would be easier). will see if CA provides any benefit to them. whats the favoured method for you guys doing class A?? just the simple resistor hack or are yo guys mainly using caps as well?? the SMT resistor trick is soo doable, but its a bit rough IMO, maybe not suitable for some circuits/OPAMPS to stay in class A


----------



## ROBSCIX

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_indeed they are very nice IMO, i'm doing a class A adapter for the OPA211, so if that works nicely i'll use some of the 1611 as well. was going to save a couple for use in a possible transportable PCM1794A dac i'm thinking about building, so might just stick with 211CA, or make a socketed CA adapter if it will fit in D10 (perhaps bias the socket that is in there somehow, hardwired would be easier). will see if CA provides any benefit to them. whats the favoured method for you guys doing class A?? just the simple resistor hack or are yo guys mainly using caps as well?? the SMT resistor trick is soo doable, but its a bit rough IMO, maybe not suitable for some circuits/OPAMPS to stay in class A_

 

Yes post your results. I have not done any Class A testing as of yet as I am waiting for some parts and doing more research into the subject.
 the 211 is nice and I would be interested in reading your impressions for those in Class A also. IIRC, a couple in here are just using the resistor for the bias current. 
 Can you shed some light on the purpose of the cap for the class A procedure, are these just different methods to get the same results?


----------



## qusp

well to be honest i've only recetly started playing around with the idea of biasing and modding opamps past rolling and the simple class A resistor mod, but with all the fus about class A and many seeming to just do it to anything that allows it (or even if they dont) I thought I would do some reading on the subject. again i'm no expert in this area, but the way I read it, class A is to keep the bias current high consistently as opamps work better when the outputs are outputting current consistently, many do this simply by placing a resistor across to load them and keep the opamp working even when it isnt being being fed anything, like in a gap or quiet passage , but depending on the signal being fed to the amp and what else is going on in the circuit, the opamp load will drop below the point of highest efficiency and out of class A operation. 

 see here is where I prove how little I know about this area, having only done the resistor method myself. capacitence was stuck in my mind for some reason, but not a positive one, 
	

	
	
		
		

		
		
	


	




 basically I was reading our good man Tangent's site the other night late after an already long night of reading, check thispage on the subject. I would likely make a mess of explaining it properly. the CRD (Current regulating diode) method is the one I am looking at trying as it should fit in the D10 if i'm lucky; whether the battery is up to the task I dont know yet. the JFET cascode method is basically what is used in the Lisa III output stage AFAIK with the AD744


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Anybody else testing the OPA1611 or 1612?_

 

I've got a couple in my P3+ this evening but I may need to tweak my Buffer and Ground configuration because at this moment in time they are pretty unspectacular..... more later if I hit the sweet spot


----------



## 12Bass

Perhaps a bit of a digression... however, I'm wondering if using a resistor to create a "class A" bias on the output affects DC offset; I suspect that it would. Not sure that would work well in those circuits which are DC coupled (have no capacitors in line with the output).


----------



## SpudHarris

Oh man don't start getting me all worried again about the dreaded DC Offset 
	

	
	
		
		

		
		
	


	




 It took all the courage I had to even try the LT1363's with my beloved JH13's......

 I still haven't got a clue how to measure it


----------



## 12Bass

Very simple... just set your multimeter for volts (or preferably mV) and measure between each output and ground. Zero is ideal.... less than 20mV is acceptable. DC offset is more of an issue for circuits which are DC coupled. In other words, if there's a big capacitor between the op amp and the output, it is probably AC coupled, and unlikely to have significant DC offset.


----------



## leeperry

Quote:


  Originally Posted by *Apocalypsee* /img/forum/go_quote.gif 
_I wanted to buy OPA211 that people been praised about, but the prices are mind boggling_

 

I've got 4*OPA211 on browndog's that I don't plan on using anytime soon, maybe we can work something out if you got anything to trade them for


----------



## leeperry

Quote:


  Originally Posted by *better* /img/forum/go_quote.gif 
_I'm starting to focus the imperfections of the LME49720HA more. 

 It has this kind of metallic feel to it (surprising!?) that its DIP counterpart just didn't show..._

 

oooh yes! 49720HA has a nasty metallic resonant sound that's hard to bear...but I only tried it on sub-$200 soundcards, anyway the OPA2132P just kills it


----------



## 12Bass

Hmmm.... wonder if some of you might be experiencing the effects of oscillation? Perhaps the circuits being used are not optimized for high speed op amps? Could try adding a capacitor across the power leads to see if it changes the tonality. I generally make sure to add decoupling capacitors whenever I use "premium" op amps.


----------



## qusp

Quote:


  Originally Posted by *better* /img/forum/go_quote.gif 
_I'm sure that you'll be the first to report me to the authority. 
	

	
	
		
		

		
		
	


	






 At any rate... Is it just me to find this talk about class A biasing opamps wrongly put and mostly stupid?

 Wrongly put because you really are only biasing one transistor in the output stage of the opamp into class A (making it work as a single ended output stage and not complementary anymore, the benefit of which is arguable). You don't touch the rest of the opamp which continues to work in class AB or even class B (LM6171/6172).


 Stupid because... what the hell! Look at the distortion figures of these opamps, LME49710/49720, OPA211/2211, OPA1611/1612... Don't they look optimised enough? You might be surprised to find that their distortion only increases if you place that resistor on the output to class-A bias one of the two complementary transistors of the output stage, drasticly lowering the output current of the opamp...

 That of class A biasing opamps is merely a legacy of a past where opamps were much more imperfect, so much as to sometimes benefit by such a compromising trick.._

 

indeed, i'm totally with you on this, that is what I have been alluding to in my posts, but you just put it more eloquently, I am still trying it with the OPA211 to test, but I agree simply doing it by default, even with modern opamps that already measure so well its silly, seems a bit ....silly 
	

	
	
		
		

		
		
	


	




 and this is also why I called the simple resistor bias a 'hack' because they often arent remaining in class A at all.

  Quote:


  Originally Posted by *better* /img/forum/go_quote.gif 
_Regarding the OPA1611, I'm still very interested, even though judging by the numbers (which never deceive, as I've learnt - while your ears can deceive and delude...), the OPA1611/1612 is going to have a slightly monochromatic tonality similar to that of the OPA211.

 The LME49723 and OPA132UA are my all around best sounding opamps, and with good reason. 
	

	
	
		
		

		
		
	


	


_

 

well i'm not finding them so much monochromatic, but have taken the 1612 buffers out, because the combination of 1611 (I/V) and 1612 as buffers is a touch smooth with some rock and edgier electronica. now awaiting my OPAMPs from texas components to arrive 
	

	
	
		
		

		
		
	


	




 took one for the team and ordered some. the specs are like no other we have seen and with a price to match 
	

	
	
		
		

		
		
	


	




 at $60USD a pop for a dual DIP8 package. I wont be using class A with them thats for sure.

  Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Hmmm.... wonder if some of you might be experiencing the effects of oscillation? Perhaps the circuits being used are not optimized for high speed op amps? Could try adding a capacitor across the power leads to see if it changes the tonality. I generally make sure to add decoupling capacitors whenever I use "premium" op amps._

 

SMT caps?? what value is recommended? would a small .47uf BG NXHQ do? i'll try that out and report back if .1 or .47uf will suffice. other values I have are 22uf, 47uf. not that i'm experiencing any treble resonance to speak of. in fact nothing spikey about the FR at all


----------



## murrays

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_SMT caps?? what value is recommended? would a small .47uf BG NXHQ do? i'll try that out and report back if .1 or .47uf will suffice. other values I have are 22uf, 47uf. not that i'm experiencing any treble resonance to speak of. in fact nothing spikey about the FR at all_

 

Don't use electrolytic caps for extra bypassing to stop oscillation. You want them to be effective up into the VHF MHz range. Presuming that you already have electrolytics in the circuit, you should try bypassing with values between 0.01 uF and 0.1 uF, keeping lead lengths as short as possible (and close to IC voltage pins). Electrolytics don't function as a good capacitor in the MHz range, ceramics do. The op-amp circuit will "look" completely different to frequencies in the MHz range compared to the audio range: e.g. adjacent wires start looking like coupling capacitors, capacitors start looking like inductors or resonant circuits, gain and phase will be different, etc. Just because you can't hear it (MHz), don't think that the op-amp won't try to process it.


----------



## cobaltmute

I have read elsewhere with many liking the results of 100uF Panasonic FMs on the + and - pins to ground and 100nF between the + and - for decoupling.


----------



## murrays

Quote:


  Originally Posted by *cobaltmute* /img/forum/go_quote.gif 
_I have read elsewhere with many liking the results of 100uF Panasonic FMs on the + and - pins to ground and 100nF between the + and - for decoupling._

 

Yes, the 100nF (0.1 uF) capacitors are doing the high frequency bypassing in this case. It's important to keep the leads short to ensure effectiveness at the high frequencies. The 100uF electrolytics will be doing the bulk of their work filtering the lower frequencies (i.e. < 100 kHz) from the power rails.


----------



## qusp

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_Don't use electrolytic caps for extra bypassing to stop oscillation. You want them to be effective up into the VHF MHz range. Presuming that you already have electrolytics in the circuit, you should try bypassing with values between 0.01 uF and 0.1 uF, keeping lead lengths as short as possible (and close to IC voltage pins). Electrolytics don't function as a good capacitor in the MHz range, ceramics do. The op-amp circuit will "look" completely different to frequencies in the MHz range compared to the audio range: e.g. adjacent wires start looking like coupling capacitors, capacitors start looking like inductors or resonant circuits, gain and phase will be different, etc. Just because you can't hear it (MHz), don't think that the op-amp won't try to process it._

 

ok thanks, I cant say that I think that a plain pair of 1611 will be needing much attention to be honest, but if I start using them in class A i'll play around with this. I have already replaced the power rail and output caps in the D10 with BGNXHQ (470uf and 220uf) and bypassed the power rail with .47uf

 i'm with you on my lack of superhuman hearing, I dont claim the circuit perfect because I cant hear any problems, but i'm pretty time poor these days, so would prefer to tackle issues because I need to or if something is bothering me. all the same thankyou for taking the time to answer and explain, I will take it into account for sure.

  Quote:


  Originally Posted by *cobalmute* 
_I have read elsewhere with many liking the results of 100uF Panasonic FMs on the + and - pins to ground and 100nF between the + and - for decoupling._

 

ah stuff it, you got me, i'l play around with it sometime in the next week or so, i'm ast running out of room in the D10 though, but do have a little spare since changing from a side by side SOIC8 to DIP8 adapter to a stacked one, so gain a bit of space there.


----------



## murrays

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_ah stuff it, you got me, i'l play around with it sometime in the next week or so, i'm ast running out of room in the D10 though, but do have a little spare since changing from a side by side SOIC8 to DIP8 adapter to a stacked one, so gain a bit of space there._

 

I find that it is convenient to solder the bypass capacitors to the underside of the circuitboard. They are quite small and it makes it easy to do a direct point-to-point connection. You can solder them across the pins of the electrolytics, between the op-amp power pins, or variations/combinations of both depending on the layout).


----------



## 12Bass

FWIW, I've never heard anything "spikey" in the LM4562. My impression might be along the lines of flat, analytical, decently detailed, and somewhat sterile, with a slightly lean low end.... but not harsh or edgy. That's why I'm curious about possible circuit implementation issues.

 Sometimes I'll put a 0.1 µF ceramic directly across the power pins, soldered right on the SOIC>DIP adapter.


----------



## qusp

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_I find that it is convenient to solder the bypass capacitors to the underside of the circuitboard. They are quite small and it makes it easy to do a direct point-to-point connection. You can solder them across the pins of the electrolytics, between the op-amp power pins, or variations/combinations of both depending on the layout)._

 

I just solder direct to the leads for bypassing when I can, i'll try and grab some ceramic caps with the next order, any one in particular?? the X7 do?? I have some here already I think left over as extras from my gamma1 build. will see how the new opamps go in a couple weeks, might even give it a go with the adapters on OPA211


----------



## leeperry

Quote:


  Originally Posted by *better* /img/forum/go_quote.gif 
_Agreed. The LM4562 is [..] certainly nice (better than the LT1364 overall)._

 

right, sounds like someone is in a playful mood today 
	

	
	
		
		

		
			





 bass is anemic on the 4562, SS is uber-wide and artificial, trebles are whiney...everything majkel said basically: http://www.head-fi.org/forums/f6/aud...-v-2-a-397691/


----------



## leeperry

I don't know what "colorful" audio means....but the vocals simply sound unreal w/ the 1364, the SS is very natural, the low end is good(the mid bass is not great, though) and the trebles are spot-on....and the better the PSU, the clearer trebles get.

 I'm still waiting on my 1363/1028, I'm eager to try them...but the OPA132U was a let down compared to the 2132P, the fantastic low end bass response was just GONE(due to lower EMI/RFI shielding?)

 and the LME49722 was unbearable...like a whinier 49720NA


----------



## leeperry

quite honestly the 1364 hits the spot for me, vocals sound so gooooood...LT recommends it as one of the top choices for a reason, and not too long ago you also loved it IIRC 
	

	
	
		
		

		
		
	


	




 my next upgrade will be replacing the 2132P by a burson I think, but only after/if I'm bored of my current setup...but I've recently improved the PSU side, and man does it give! running op-amps on a <1mV ripple PSU or batteries must be quite a blast


----------



## ecclesand

I have been listening to a pair of OPA627 as line drivers for my Lite DAC-AH (15V). I now see why these little suckers are so expensive. They are simply outstanding to my ears and excel in every area. This is not one of those cases where these opamps do nothing wrong...these do everything right. I had considered a passive output on this DAC using some nice Auricaps or Mundorfs (and may still do it), but with the opa627, I am certainly in no rush.


----------



## leeperry

Quote:


  Originally Posted by *better* /img/forum/go_quote.gif 
_A $150 opamp on a $200 soundcard? You sure? 
	

	
	
		
		

		
		
	


	




 And that is supposing that it sounds as good as it costs..

 If I were you, I'd put two LT1028CS8 per socket for the I/V position, and one LME49723 for the output buffer (or leave the LT1364 if you were to find that you prefer this 
	

	
	
		
		

		
		
	


	




 )._

 

my soundcard is based on an AK4396, that doesn't need any I/V(for which the Burson is said to be so-so)...it's got 2 initial buffers(I/V-like prolly), and then a last buffer, and then it goes through the high gain JRC4580 to drive my cd1k(that increases the bass control tremendously!)

 in that last buffer, I don't think anything will top the OPA2132P....it just sounds too awesome, very liquid/detailed mids, fantastic bass response(both low-end and mid), very clear non-whiney trebles...too good 
	

	
	
		
		

		
		
	


	




 but yes, I will try to replace the 2*1364 by 4*1028/1363....but well I don't think the 1028 will excel on vocals the same way the 1364 does, and browndog's seem too sensitive to EMI/RFI 
	

	
	
		
		

		
		
	


	




 well, I'm quite a projector enthusiast, and burson says that their chips are like a pj lens...a good pj w/ a crappy lens is worthless(blurry corners/random patches, poor sharpness, double edges)...I will prolly try to replace the 2132P by a dual burson(costs ±50 EUR).

 it's not supposed to sound any wider or clearer or anything like that...it's just supposed to make the sound "flow"(a bit like the 2132P, but even further) and sound analog(as to "not 4562 digital-like").

 National likes to boast about killer THD specs(and TI plays the same game w/ their newest chips)....but if low THD means no bass and whiney trebles, then I'm not interested 
	

	
	
		
		

		
		
	


	




 THD and crosstalk are plain bad w/ the burson, but the SQ is supposed to be totally unmatched...the human brain is not meant to listen to pure sine waves(easy to find out w/ synthesizers, that need heavy PP to sound good).


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I have been listening to a pair of OPA627 as line drivers for my Lite DAC-AH (15V). I now see why these little suckers are so expensive. They are simply outstanding to my ears and excel in every area. This is not one of those cases where these opamps do nothing wrong...these do everything right. I had considered a passive output on this DAC using some nice Auricaps or Mundorfs (and may still do it), but with the opa627, I am certainly in no rush._

 


 Yes. They are considered by many to be one of the best audio opamps avialable.
 I have both the 627 and 637 and while the 637 is a bit touchy in many circuits I like it's high end extension a bit better then the 627.
 The 627 is a great opamps though and it come highly recommeneded

 Ont he building front: I am considering building a matched set of 627 & 637 TO-99 modules for my circuit tests.


----------



## SpudHarris

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I have been listening to a pair of OPA627 as line drivers for my Lite DAC-AH (15V). I now see why these little suckers are so expensive. They are simply outstanding to my ears and excel in every area. This is not one of those cases where these opamps do nothing wrong...these do everything right. I had considered a passive output on this DAC using some nice Auricaps or Mundorfs (and may still do it), but with the opa627, I am certainly in no rush._

 

I'm with you there Doug for sure, they really are superb. Personally (in the right application) I prefered the 637's but I can only use them in my P3 and my PPA, I'd love to use the 637's in my P3+ but they are way unstable even with the gain on it's highest setting. That said, to my ears the 627's are veeery close on SQ.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I'm with you there Doug for sure, they really are superb. Personally (in the right application) I prefered the 637's but I can only use them in my P3 and my PPA, I'd love to use the 637's in my P3+ but they are way unstable even with the gain on it's highest setting. That said, to my ears the 627's are veeery close on SQ._

 

I agree with you there. I still prefer the 637 as I enjoy the high range but they are very touchy because of no internal compensation. IIRC, they need a gain of 5 or more. I am waiting to build a set of matched TO-99 modules of both the 627 and 637's.


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I agree with you there. I still prefer the 637 as I enjoy the high range but they are very touchy because of no internal compensation. IIRC, they need a gain of 5 or more. I am waiting to build a set of matched TO-99 modules of both the 627 and 637's._

 

Man you must be made of money 
	

	
	
		
		

		
			





 the TO-99 versions of the 637's are so so expensive. Which version? AM, BM, SM? Farnell has the SM @ £99.90 so pretty much $200 each 
	

	
	
		
		

		
		
	


	




 I'll just stick with my BP's I think. If you know where to get the TO-99's at a reasonable price I would be interested to know.


----------



## Reima

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Post your impressions. I have been using dual LME49710HA's for quite some time. There are quite a few others that are starting to check out this units also and all reports seem positive. The dual single channel modules sound different and arguably better then the single dual channel model. -according to reports._

 

I haven't had a chance to listen since I put in the dual module. Today I swapped out the Panasonic volume contol for an Alps RK097 and the BUF634's for LMH6321's. Hopefully I will get some time to do some listening this weekend.
 RC


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Man you must be made of money 
	

	
	
		
		

		
		
	


	




 the TO-99 versions of the 637's are so so expensive. Which version? AM, BM, SM? Farnell has the SM @ £99.90 so pretty much $200 each 
	

	
	
		
		

		
		
	


	




 I'll just stick with my BP's I think. If you know where to get the TO-99's at a reasonable price I would be interested to know._

 

No, I have good suppliers overseas. They seem to be able to find me anything I need for a fraction of the price. Some units are pricey no matter where you look. I have found opamps that are more expensive then the 627SM units and said to be very good for audio. There are still TO-99 models but of a different model number. I am considering building some of these also. 
 I will be using the 627SM and 637SM opamps. I have seen them locally for about $90 a unit and you need two...
 Do you mean Farnell has a dual unit module or they are charging $200 per unit?


----------



## SpudHarris

*Per unit* they are in stock at £99.90 which actually is about $150 at todays conversion rate.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_*Per unit* they are in stock at £99.90 which actually is about $150 at todays conversion rate._

 

Whoa that is really expensive! 
 I like the sound of them and get them for less then that so I am going ahead with matched pairs of the dual 627 and 637SM modules. I will post pics when they are done.


----------



## SpudHarris

Nice one, looks like you and I are one of the few who still rate the 637's by the sound of it. I have the BP's and 2 x SOIC versions on Brown Dog (type) adapters just can't use them in my favourite portable amp. What are you going to use them for?

 I tried the OPA1611's again last night and I just can't take to them. I've tried everything from different buffers and G/VG chips, I've tried bypassing buffers and/or G/VG and nothing seems to make them sound anything but mediocre. I've still got a couple of these that I haven't mounted if anyone's interested?


----------



## ecclesand

I think I need to study the OPA637 datasheet to see if it will work in the Dac-AH. You guys have my interest piqued. Oh, and the OPA627SM is around $70 at Digikey, but you have to buy 20 of them. OUCH!


----------



## SpudHarris

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I think I need to study the OPA637 datasheet to see if it will work in the Dac-AH. You guys have my interest piqued. Oh, and the OPA627SM is around $70 at Digikey, but you have to buy 20 of them. OUCH!_

 

Just checked e-bay and there is a reputable seller with the TO-99 637's for about £22 delivered, if only I could stabilise them in the P3+ 
	

	
	
		
		

		
		
	


	




 even ibasso had a go and the only way they could do it was by changing the resistor set to that of the P3 which kind of defeats the object of having the P3+.......


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Nice one, looks like you and I are one of the few who still rate the 637's by the sound of it. I have the BP's and 2 x SOIC versions on Brown Dog (type) adapters just can't use them in my favourite portable amp. What are you going to use them for?

 I tried the OPA1611's again last night and I just can't take to them. I've tried everything from different buffers and G/VG chips, I've tried bypassing buffers and/or G/VG and nothing seems to make them sound anything but mediocre. I've still got a couple of these that I haven't mounted if anyone's interested?_

 

I enjoy the 6X7 series. The 627 are great and I like th 637 even more although touchy in a great deal of circuits. I am not sure exactly what I am going to use them for yet. I have a very large collection of opamps and I want to add more of this series to the bin.
 I have 3 dual 1611's modules that I have been testing here and there. Based on what I heard so far they seem decent enough but like others some may like them and some may not.
 I will post pics when I build the dual TO-99's. Might be a month or so...


----------



## Reima

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Just checked e-bay and there is a reputable seller with the TO-99 637's for about £22 delivered, if only I could stabilise them in the P3+ 
	

	
	
		
		

		
		
	


	




 even ibasso had a go and the only way they could do it was by changing the resistor set to that of the P3 which kind of defeats the object of having the P3+......._

 

What grade are they AM or SM?
 RC


----------



## SpudHarris

Quote:


  Originally Posted by *Reima* /img/forum/go_quote.gif 
_What grade are they AM or SM?
 RC_

 

AM....... Here's the link: OPA637AM

 Can't imagine there would be a world of difference between the two, unless someone can say otherwise.


----------



## Slash47

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_AM....... Here's the link: OPA637AM

 Can't imagine there would be a world of difference between the two, unless someone can say otherwise._

 

Just want to say that I strongly advice against buying OPA627 from Ebay.

 LOTS of fakes, often without the seller knowing it (or acting that way).


----------



## SpudHarris

I know, I got burned once myself bying the DIP versions via e-bay. However, this seller has 27 sold in his history and buyers left positive feedback so I assume these are the real deal. Even so you can never be too sure, granted.


----------



## Slash47

Well that's cool, then he's cheap 
	

	
	
		
		

		
		
	


	




 I'm gonna print me a nice opamp rolling platform 
	

	
	
		
		

		
		
	


	




http://www.gooipcs.nl/media/pcm.pdf

 I was bored tonight so I stole a bunch of designs an chucked 'm together... Don't mind the errors. 

 Should sound alright though! I also have a oak board here, so I'll do some DIY-ing. Uber CMOY FTW!!! 
	

	
	
		
		

		
		
	


	




 I'm thinking 2x AD797 (I/V) -> Burson opamp (Output) -> OPA2132 (Dual CMOY) for each channel. Could go OPA627BP for the last bit, but meh...


----------



## crapback

All this talk about X27's reminded me. For those of us who oredered samples, 827's should be on the way in about two weeks.
	

	
	
		
		

		
		
	


	




 I guess that'll give me a reason to switch out the hdams in my zero.


----------



## leeperry

which HDAM? I remember a guy on a french forum compared the old burson and the audio-gd earth...and both the PCB and components were perfectly identical! now whether the new (reversed) burson would be an improvement is another question altogether.


----------



## crapback

Oh ya, it's been a while since I've played with opamps and kept up with this thread. 
	

	
	
		
		

		
			





 I have three earth's in my zero. If I can get the output jack working correctly I'll be all set.


----------



## leeperry

yeah, I can't really justify the price of the new burson...but the earth is pretty cheap(less than half price).

 I'm so happy w/ my current setup, I don't really see what could be improved...but apparently it'd kill my 2132P buffer


----------



## SpudHarris

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_All this talk about X27's reminded me. For those of us who oredered samples, 827's should be on the way in about two weeks.
	

	
	
		
		

		
		
	


	




 I guess that'll give me a reason to switch out the hdams in my zero._

 

Thanks for the nod. I ordered mine months ago and keep checking on TI but the dates just keep slipping, originally going to be delivered beginning of Sept.


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_All this talk about X27's reminded me. For those of us who oredered samples, 827's should be on the way in about two weeks.
	

	
	
		
		

		
		
	


	




 I guess that'll give me a reason to switch out the hdams in my zero._

 

I was told they were out of stock in some places...


----------



## Slash47

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_yeah, I can't really justify the price of the new burson...but the earth is pretty cheap(less than half price).

 I'm so happy w/ my current setup, I don't really see what could be improved...but apparently it'd kill my 2132P buffer 
	

	
	
		
		

		
		
	


	


_

 

You're right, I wouldn't promote it either unless you do other things as well.

 Have you tried 2x OPA2132 -> LT1358/61 or 2x LT1364 -> LT1358/61? Should both be up your alley and either might be slightly better configs.


----------



## leeperry

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_You're right, I wouldn't promote it either unless you do other things as well.

 Have you tried 2x OPA2132 -> LT1358/61 or 2x LT1364 -> LT1358/61? Should both be up your alley and either might be slightly better configs._

 

actually I haven't...first I took off the final buffer to first find my favorite primary buffers(the 1364 is so milky on vocals, I'm in love 
	

	
	
		
		

		
		
	


	




), but its mid-bass is somewhat recessed....gap the OPA2132 fills nicely, and it increases the LT1364 vocal resolution even further 
	

	
	
		
		

		
		
	


	




 I'll write down your suggestions for the day I'll be bored


----------



## ROBSCIX

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_You're right, I wouldn't promote it either unless you do other things as well.

 Have you tried 2x OPA2132 -> LT1358/61 or 2x LT1364 -> LT1358/61? Should both be up your alley and either might be slightly better configs._

 

I would say it depends on what your putting the unit into. If the device has other shortcomings then you would get the most gains from addressing these issue first and use the discrete opamp as the final touch.

 Many mods such as power caps, coupling, power etc..can offer great gains just by swapping them out with higher grade units. However, I think you arleady know this judging on the pic you posted of the modded card.


----------



## SpudHarris

I still think that the 1363's are the best Opamps for vocals but as usual after getting used to their signature I'm bored again. So I'm back to the AD797's and these really are superb and suit electronica/ambient trance better than the 1363's 
	

	
	
		
		

		
		
	


	




.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I still think that the 1363's are the best Opamps for vocals but as usual after getting used to their signature I'm bored again. So I'm back to the AD797's and these really are superb and suit electronica/ambient trance better than the 1363's 
	

	
	
		
		

		
		
	


	




._

 

Have you tried any other AD opamps such as 8599, 8610's, or 8620...etc?


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Have you tried any other AD opamps such as 8599, 8610's, or 8620...etc?_

 

Yeah, got pretty much all the well knowns I think...

 797
 4898-1
 744
 825
 8610
 843
 827
 712
 8599
 823
 8066
 8397


----------



## Slash47

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Yeah, got pretty much all the well knowns I think...

 797
 4898-1
 744
 825
 8610
 843
 827
 712
 8599
 823
 8066
 8397_

 

What do you think about the AD8066 and 8599? They are spot on neutral imo, without losing PRaT. Both need a really good PSU though, or a battery.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Yeah, got pretty much all the well knowns I think...

 797
 4898-1
 744
 825
 8610
 843
 827
 712
 8599
 823
 8066
 8397_

 

I was using the 8599 for quite awhile but have yet to try some of the others.


----------



## SpudHarris

If I'm truthful I've not spent much time with either up until now. I've been so embroiled in getting my G/VG and buffers sorted that I've still got a lot of Opamps to get through. I have the OPA1611's and LT1677's also that I need to spend more time with.

 The problem is that sometimes I just want to sit and listen to something that feels like home, something I'm used to and love and that suits my favourite genres. The AD797's have been in my collection for a long time and no matter how many others I test and love for a while I seem to always come back to them in the end. 

 The P3+ comes with a rolling kit of different Opamps, Buffers and dummies so you play around with what sounds good to you. The chances are that only a small number of configurations are actually doing anything right, the majority will probably sound different, sometimes sweet but in reality may be distorted or un-natural. The set up I have coupled with the AD797's just hit the spot (to my ears at least) and sound so good on every level I know why I always go back to them.


----------



## Slash47

Hey, I agree with you. The problem is a lot of the time you can't use a AD797 as a replacement but if you can there is absolutely no reason not to use it. I'd describe a AD8599 as a 98% AD797 in a dual package and the AD8066 as 98% in dual FET.


----------



## ROBSCIX

@Slash, you prefer AD8599 over AD797?
 Not really understanding your math there.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_If I'm truthful I've not spent much time with either up until now. I've been so embroiled in getting my G/VG and buffers sorted that I've still got a lot of Opamps to get through. I have the OPA1611's and LT1677's also that I need to spend more time with.

 The problem is that sometimes I just want to sit and listen to something that feels like home, something I'm used to and love and that suits my favourite genres. The AD797's have been in my collection for a long time and no matter how many others I test and love for a while I seem to always come back to them in the end. 

 The P3+ comes with a rolling kit of different Opamps, Buffers and dummies so you play around with what sounds good to you. The chances are that only a small number of configurations are actually doing anything right, the majority will probably sound different, sometimes sweet but in reality may be distorted or un-natural. The set up I have coupled with the AD797's just hit the spot (to my ears at least) and sound so good on every level I know why I always go back to them._

 

I hear ya. I have so many opamps to test and so many in my collection I like. Units others are sending me...testing this testing that. Mnay times as you said, it is nice to pop in a tried and true unit or set and just listen for a bit. I think many of the people new to opamps get too caught up in the testing phase and forget just to sit and enjoy the sound once in awhile instead of just analyzing it for good and bad points.
 I have a AD797 and enjoy it't sound but I have others that I seem too like more based on older testing. Hell, I will through in the AD707 and check it out again....been awhile.


----------



## Slash47

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_@Slash, you prefer AD8599 over AD797?
 Not really understanding your math there._

 

I tried to say that the AD8599 is 98% of an AD797 in a dual package. So I prefer the AD797 by 2%


----------



## ROBSCIX

That makes sense.
 Just popped my AD797 in for more testing seems to be a great mix with this DAC.
 Forgot how good this little guy sounds...
 Will leave this in for the day or week.


----------



## SpudHarris

I love rediscovering the stuff i haven't tried for a while. Tonight I'm listening with the 797's for nothing else but pleasure. However, I may roll some different headphones instead haha 
	

	
	
		
		

		
		
	


	




. Hmmm Denon's, Grado's Senn's, Q-jays and probably end up with the JH13's again.......


----------



## ROBSCIX

Sure. I am going to leave the AD797 in for awhile and see what it brings to me as I haven't listened to it in quite awhile.


----------



## SpudHarris

Do tell, Im learning every day and today is no different. I am thirsty for knowledge of this subject.


----------



## SpudHarris

Ahhh, so one of the reasons I may not be shouting about those or the LT1677's is because my buffer section may need looking at. I will try again this evening with various buffers, may have better luck with stacked buf634's.

 Thanks for that.....


----------



## mark2410

okay i may be about to sound like an idiot but really dont know this stuff.

 so got an xm5, nice but wanted a but cooler and more mids, read the LM6171 could be good so i ordered some. stuck 2 in today and good sound.

 problem, in one song in particular beverly craven [ hope at 1:50 in as the lows come forth the mids are really vanquishing off. its live there isnt enough current to drive the bass and everything else too at the same volume.

 thoughts? is this what buffer chips are for?


----------



## ROBSCIX

The LM6161 may not be a good match with the circuit your using. You may be right it moght not be providing the proper output levels for the circuit. Hard to say with looking over the circuit and measuring it. What opamp was in there stock? -to note, I am not familiar with the Xm5. Maybe another member has more expereince with this circuit.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Do tell, Im learning every day and today is no different. I am thirsty for knowledge of this subject._

 

There is some great info out there if you look around. I find application notes manuals from the companies are good reads. They explain the various circuits and what they are supposed to do.
 Not all sites have them but many manufacturers have engineers which write them for other designers.


----------



## crapback

I just got two emails from TI today about my 827 orders. I didn't keep track of what I had ordered and doubled up on a few opamps. Anyone else get anything from TI?


----------



## mark2410

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_The LM6161 may not be a good match with the circuit your using. You may be right it moght not be providing the proper output levels for the circuit. Hard to say with looking over the circuit and measuring it. What opamp was in there stock? -to note, I am not familiar with the Xm5. Maybe another member has more expereince with this circuit._

 

it had in it before AD8397


----------



## SpudHarris

With the 8397 it's likely you didn't have separate buffers installed as that Opamp has an internal buffer(s). I had the XM4 for a while which was well really suited to the AD8620. I do like the 6171's though, have you any buffers behind them? If not I would drop a couple of buf634's in there and see if it helps, it doesn't hurt to have a few different buffers around if you are going to roll your Opamps.


----------



## mark2410

ahh okay so is there an assortment of buffer options people might be able to recommend?

 how might they change the sound or should they not change anything?

 i feel so utterly clueless about all of this


----------



## SpudHarris

There are different buffers available Mark and yes they probably will change the sound, sometimes quite drastically. In my experience they seem to make the sound fuller if you like, making portables such as the XM5 and my P3+ more like or closer to that of a home based amp. Buf 634's seem to be very popular and are my personal weapon of choice although the ibasso stock transistor buffers are also great.

 Before you get the wrong idea I'm not technically qualified to explain the why's and wherefor's of buffers or Opamps for that matter. I am learning from the knowledgable guys here on this thread and hopefully getting some reading matter on the subject soon. have you read Tangents notes?? It may be a good place to start if you are interested.


----------



## mark2410

that will be interesting reading but maybe for another night

 oh dear just too many variable getting in all of this


----------



## SpudHarris

Because??


----------



## ROBSCIX

Quote:


  Originally Posted by *mark2410* /img/forum/go_quote.gif 
_that will be interesting reading but maybe for another night

 oh dear just too many variable getting in all of this_

 

It can get to be a bit of a hobby in itself. Talk with people that have tested the unit your interested in. Your ears have to make the final call though.


----------



## ROBSCIX

@Spud, hows your class A testing going? 
 ..or are you still testing the AD797?


----------



## SpudHarris

Well Rob, after our talk of rediscovering stuff I went through my Opamps and pulled out the AD823 which as you may know is used in the Solo (Graham Slee). Wow that opamp is so nice, at the moment I'm listening with the same buffer and G/VG set up as the 797's and it is superb. Another thing worth remembering about testing older stuff is that things may have moved on. I don't think I've used the 823 in the P3+ before and certainly not with my JH13's so maybe I'm seeing things differently.

 I have bitten the bullet and biased the 49710HA's to class A with the resistor on the underside of the brown dog (post pics later) I haven't had chance yet to review them but will post impressions when I get a mo.

 On the OPA1611's - I have had another crack at these after Andreas earlier explaination of ''Rail to Rail''. I used every combination of buffer and G/VG I could think of and they still leave me cold. Can only assume they don't suit the P3+ circuit. Maybe I'll drop them in the PPA and see if they are any better.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well Rob, after our talk of rediscovering stuff I went through my Opamps and pulled out the AD823 which as you may know is used in the Solo (Graham Slee). Wow that opamp is so nice, at the moment I'm listening with the same buffer and G/VG set up as the 797's and it is superb. Another thing worth remembering about testing older stuff is that things may have moved on. I don't think I've used the 823 in the P3+ before and certainly not with my JH13's so maybe I'm seeing things differently.

 I have bitten the bullet and biased the 49710HA's to class A with the resistor on the underside of the brown dog (post pics later) I haven't had chance yet to review them but will post impressions when I get a mo.

 On the OPA1611's - I have had another crack at these after Andreas earlier explaination of ''Rail to Rail''. I used every combination of buffer and G/VG I could think of and they still leave me cold. Can only assume they don't suit the P3+ circuit. Maybe I'll drop them in the PPA and see if they are any better._

 

I am interested in your results for the LME49710HA's and the biasing resistors.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I am interested in your results for the LME49710HA's and the biasing resistors._

 

Me too. Oh...and tell us if they get hot. On the dual unit I made, for a heatsink, I took a hacksaw to an old southbridge heatsink I wasn't using. It's ghetto, but it worked. Of course, since then I have discovered microsinks as I bought 8 of them for the DAC chips in my Lite Dac-AH.


----------



## crapback

What kind of small heatsinks did you get ecclesand? I was thinking about ordering another set of Swiftech copper ramsinks before I got some hdams.


----------



## leeperry

I personally put some zalman blue heatsinks that are usually found on graphic card's RAM...but tbh the last thing you want is attract EMI/RFI onto your op-amps.

 I'm gonna change strategy and install some Chomerics C-Wings, these are especially meant for EMI-sensitive components


----------



## Zerotohero

I’ve recently done some extensive listening and opamp rolling tests in my assemblage 2.7 dac.
 Im quite a noob at this so would appreciate some advice;

 What I found was bb637bp sounded much better than the stock opa134 output buffers, and bb627ap sounded better than the stock lt1357 iv convertors but the next one confused me.

 I tried rolling the stock opa604 dc servo stage opamps for the bb627ap and it actually sounded much worse!

 Is the 627 not designed for this task perhaps?
 Could you recommend a more suitable opamp for the dc servo stage?

 If filburt or sachu are present i know they both have experience in modding this dac very successfully...

 Thanks in advance...


----------



## Zerotohero

snip/andrea reference/snip
 Any help on my question asked above would be awesome.

 Thanks


----------



## mark2410

well since spudharris suggested the Buf634 i thought oh hell ill buy some and maybe try others later. so i go looking

Amplifiers - Instrumentation, OP Amps, Buffer Amps | Digi-Key

 as my west coast bretherin might say i havent a scooby.

 whats the difference and what should i be getting, if i had to guess i think the top one.


----------



## diditmyself

Quote:


  Originally Posted by *Zerotohero* /img/forum/go_quote.gif 
_I tried rolling the stock opa604 dc servo stage opamps for the bb627ap and it actually sounded much worse!_

 

Placebo or instability. I'd guess it's placebo. OPA627 as servo stage is such a waste. Use any stable JFET opamp with fairly low DC offset for this task.


----------



## SpudHarris

Yeah, it can get a bit confusing with the different versions. Does the £7 include VAT and Carriage or is that extra? Reason I ask is I always get my stuff from Farnell as carriage is included in the price. Unfortunately the DIP version is out of stock but the SOIC (Buf634U) is on special but needs a Brown Dog SOIC to DIP adapter.


----------



## Zerotohero

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_Placebo or instability. I'd guess it's placebo. OPA627 as servo stage is such a waste. Use any stable JFET opamp with fairly low DC offset for this task._

 

Thanks for that.
 Is there a particular model you would recommend that is better than the stock opa604?


----------



## ecclesand

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_What kind of small heatsinks did you get ecclesand? I was thinking about ordering another set of Swiftech copper ramsinks before I got some hdams._

 

Microcool Black MicroSink

 I removed the thermal tape and picked up some Arctic Silver Thermal Adhesive (the 2 part stuff you mix). They're permanently attached to my TDA1543 chips, but they sure work!


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Yeah, it can get a bit confusing with the different versions. Does the £7 include VAT and Carriage or is that extra? Reason I ask is I always get my stuff from Farnell as carriage is included in the price. Unfortunately the DIP version is out of stock but the SOIC (Buf634U) is on special but needs a Brown Dog SOIC to DIP adapter._

 

Hey Nigel...
 I did the HI-C mod on some BUF634s using some 160 OHM resistors I had handy. I recalled reading that anything under 220 would work. What do you use on your modules?


----------



## mark2410

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Yeah, it can get a bit confusing with the different versions. Does the £7 include VAT and Carriage or is that extra? Reason I ask is I always get my stuff from Farnell as carriage is included in the price. Unfortunately the DIP version is out of stock but the SOIC (Buf634U) is on special but needs a Brown Dog SOIC to DIP adapter._

 

no they a flat rate £12 postage which is a bit much really.

 i feel so lost with all this, lol


----------



## leeperry

yeah farnell and so are way over the top for shipping costs to western europe...I'll keep milking for free samples, shoot me now!

 and I don't think I'll take off my zalman heatsinks, I'm most delighted by the SQ...I've received the 1028/1363, but that'll wait until I'm bored of the 1364(if ever 
	

	
	
		
		

		
			





)

 and the more I improve the power supply to the soundcard(PSU/mobo), the clearer the trebles get and the wider the SS...unbelievable.

 but I'll try replacing the OPA2132P by an Audio-GD Earth, it's the same as the old burson...gotta be good!


----------



## SpudHarris

Quote:


  Originally Posted by *mark2410* /img/forum/go_quote.gif 
_no they a flat rate £12 postage which is a bit much really.

 i feel so lost with all this, lol_

 

I've got a couple spare that you can have for what I paid. If you are interested shoot me a pm.


----------



## SpudHarris

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Hey Nigel...
 I did the HI-C mod on some BUF634s using some 160 OHM resistors I had handy. I recalled reading that anything under 220 would work. What do you use on your modules?_

 

Nice one Doug, what do you think?? I've always used 220 as that's what was recommended to me, Hi-C are definately my favourites.


----------



## SpudHarris

I've participated


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Nice one Doug, what do you think?? I've always used 220 as that's what was recommended to me, Hi-C are definately my favourites._

 

It made a huge difference in reducing the noise floor in this little dac/amp combo I recently picked up. Very nice and thanks for posting it!


----------



## LuciferX

LTC SAMPLE REQUEST: Due the international freight and other import taxes applied by local government, we can't sample projects with low production volume or without application. <<< I want my 1364 !!!! 
	

	
	
		
		

		
		
	


	




 Describe Application * <<< What should i put here to receive my samples? (Im from Argentina)


----------



## ecclesand

Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_LTC SAMPLE REQUEST: Due the international freight and other import taxes applied by local government, we can't sample projects with low production volume or without application. <<< I want my 1364 !!!! 
	

	
	
		
		

		
		
	


	




 Describe Application * <<< What should i put here to receive my samples? (Im from Argentina)_

 

I would simply put whatever you're putting the opamps in. I typically use opamps in DACs so if it were me, I would put Audio - Digital to Analog Converter.


----------



## SpudHarris

Well OPA827's are here this morning. 2 day delivery from US to UK 
	

	
	
		
		

		
		
	


	




 I'll solder them up later and give em' a blast.

 BTW the 49710HA's biased to CA are unbelievably detailed and airy, quite different with the CA trick than standard. May be because they sound different but I'm not 100% it suits them, more listening needed...... Oh and they don't run hot just luke warm.


----------



## isleofgeorge

Hi guys,

 Beginner need some help! 
	

	
	
		
		

		
		
	


	




 Just purchased an essence stx and planing try different opamp configs. I don't use headphones, so I will be experimenting with changing the buffer and the I/V opamps as well.
 Can someone tell me what is the difference between FET and Audio opamps?
 Can they be used on both circuits, or not?
 I will start experimenting with the ones you can read about on the forum, but dunno if specific ones needed (FET/Audio) for the buffer and the I/V ot they are interchangeable.

 Thanks in advance, and have a nice day!


----------



## 12Bass

Do you mean FET and _bipolar_? Hard to make any generalizations based upon semiconductor type alone. Better to look at the specs and application, and compare on an individual basis, IMO. 

 One general guideline is that it is usually okay to replace a bipolar op amp with a FET device, but not necessarily a good idea the other way around. Some circuits have a high impedance and do not work well with bipolar devices, or can have issues with DC offset, depending on the design.


----------



## isleofgeorge

I see.

 I guess i had some confusion with different terms, because the title on the datasheet for eg. the opa2134 is "audio opamp", while the opa2132 "FET-input opamp". Although reading through the full overview both carry the FET-input term.


----------



## 12Bass

Yes, both OPA2132/34 are FET. If I had to choose between the two, I'd pick the OPA2132, though there are several others that I like better. For the most part, an 'audio' label doesn't mean too much. In fact, some people prefer op amps which work well into the video frequency range.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well OPA827's are here this morning. 2 day delivery from US to UK 
	

	
	
		
		

		
			





 I'll solder them up later and give em' a blast.

 BTW the 49710HA's biased to CA are unbelievably detailed and airy, quite different with the CA trick than standard. May be because they sound different but I'm not 100% it suits them, more listening needed...... Oh and they don't run hot just luke warm._

 

That is good to hear.


----------



## ROBSCIX

Quote:


  Originally Posted by *isleofgeorge* /img/forum/go_quote.gif 
_I see.

 I guess i had some confusion with different terms, because the title on the datasheet for eg. the opa2134 is "audio opamp", while the opa2132 "FET-input opamp". Although reading through the full overview both carry the FET-input term._

 

Don't let that term fool you. There are many opamps that people like around here and in other places that were never meant for audio work.
 To know which you like better you woudl have to try both on your gear and make up your own mind.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well OPA827's are here this morning. 2 day delivery from US to UK 
	

	
	
		
		

		
		
	


	




 I'll solder them up later and give em' a blast._

 

Good, our first catch of the day! 
	

	
	
		
		

		
		
	


	




 let us know, mine are pending


----------



## LuciferX

HT Omega Support:

_"For your case, I recommend using OPA2132 for U8 and U10 . And LT1364 for U9 and U11" _

 So this will mean: AK4396 > OPA2132 > LT1364 > HP/Front Line Out

 Leeperry, this order is the same as yours? My Claro Halo dont have a 4580 soldered in the end (My card admit change 2*(U8+U10) or 4(*+U9+U11) opamps so the HP/Line out will be "direct" (you say that the 4580 in your card are for "bass control" or something like that)


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Yes, both OPA2132/34 are FET. If I had to choose between the two, I'd pick the OPA2132, though there are several others that I like better. For the most part, an 'audio' label doesn't mean too much. In fact, some people prefer op amps which work well into the video frequency range._

 

You prefer the 2132 over the 2134? I found the 2132 quite boring.. in the circuit I tested IIRC. The 2134 is not exactly the best out there either but it seems better then the 2132. However, I tested those awhile back in a different circuit maybe I should run more testing an try these out again.


----------



## Apocalypsee

Done few mods to my analog out, I ditch the Elna decoupling caps with Rubycon NX HiQ, although its double the value (47uF instead of 22uF), after been hearing how it sounds with LT1363, I try LT1677. 

 Clearly the Rubycon clearly does not makes it bright and edgy like Elna did, although maybe its because the higher capacitance roll off higher frequencies too and ramp up the bass, but thats good! I no longer needs my subs, it got detail and bass now at low volume! Pretty much like enabling loudness button on the amp but without bloated bass and small soundstage 
	

	
	
		
		

		
		
	


	




 Hoping to buy 22uF NX HiQ, but gotta ask the price first, I hope it won't kill me


----------



## isleofgeorge

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Yes, both OPA2132/34 are FET. If I had to choose between the two, I'd pick the OPA2132, though there are several others that I like better. For the most part, an 'audio' label doesn't mean too much. In fact, some people prefer op amps which work well into the video frequency range._

 

Thanks, this cleared some gray spots in my head . 
	

	
	
		
		

		
		
	


	




 I will try some others too, this was only an example.


----------



## isleofgeorge

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Don't let that term fool you. There are many opamps that people like around here and in other places that were never meant for audio work.
 To know which you like better you woudl have to try both on your gear and make up your own mind.
	

	
	
		
		

		
		
	


	


_

 

Thanks boss 
	

	
	
		
		

		
		
	


	




.
 I was worrying that some types won't be operating in the xonar at all.
 I will try as many as I can, (not that I dislike the defaults), but I am sure this card can sound even better. I will start with the ones which are easy to find and fairly cheap in Hungary and will go crazy trying more advanced ones (i guess).


----------



## leeperry

Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_So this will mean: AK4396 > OPA2132 > LT1364 > HP/Front Line Out

 Leeperry, this order is the same as yours?_

 

seems like it, but try both anyway.

 and I'm starting to wonder if the LT1364 is not sending some nasty DC to my phones...I hardly ever turn off my box, but sometimes when I turn it back on I get a loud "pop" and some crackling...ah, I don't wanna take them off!!! 
	

	
	
		
		

		
		
	


	




 it might also come from my overclocking somehow, need more investigation...I'll borrow a capable multimeter.


----------



## ROBSCIX

Quote:


  Originally Posted by *isleofgeorge* /img/forum/go_quote.gif 
_Thanks boss 
	

	
	
		
		

		
		
	


	




.
 I was worrying that some types won't be operating in the xonar at all.
 I will try as many as I can, (not that I dislike the defaults), but I am sure this card can sound even better. I will start with the ones which are easy to find and fairly cheap in Hungary and will go crazy trying more advanced ones (i guess)._

 

Thats the best way. We are all using different circuits and phones/speakers so our impressions are based on our experiences and gear.
 Good luck.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Yes, both OPA2132/34 are FET. If I had to choose between the two, I'd pick the OPA2132, though there are several others that I like better. For the most part, an 'audio' label doesn't mean too much. In fact, some people prefer op amps which work well into the video frequency range._

 

I just found out that new Overture 192 soundcard is running OPA132's and OPA2132's. Now I want to try them out again to verify what I remember.
 Ah circuits vary also so that is always a factor.


----------



## majkel

Both 2132 and 2134 are FET input, it's almost the same chip, the OPA2134 being of lower grade but good enough for audio and cheaper. The OPA2132PA and OPA2134PA almost don't differ, the OPA2132P seems to be better than both, so as you can see, there is now high grade "P" series for the OPA2134, either. 

 FET inputs are intended for high impedance sources so for I/V stages they are OK but you can also use some low input bias current bipolar op-amps. Just see the specs.


----------



## diditmyself

To be a _little_ provocative: I thoght we had reached a consensus. OPA2132/2134 is suboptimal for audio. There are better newer chips and there are better pricier chips.


----------



## SpudHarris

I had a late one last night as I didn't want to stop listening with the OPA827's 
	

	
	
		
		

		
		
	


	




 Man, these are awesome opamps. More listening required to know where they fit in my list, I think it might be another late one tonight


----------



## murrays

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I had a late one last night as I didn't want to stop listening with the OPA827's 
	

	
	
		
		

		
			





 Man, these are awesome opamps. More listening required to know where they fit in my list, I think it might be another late one tonight 
	

	
	
		
		

		
		
	


	


_

 

That's good to know. I was planning on trying a pair of those to replace my current OPA2134 (as voltage amplifier stage). What's holding me back is first saving to replace the ultra-cheapo pot with a quality attenuator. I think that's the weak point at the moment. I've pretty much tamed the noise on the power rails, so that will leave op amp substitution for the final tuning.


----------



## isleofgeorge

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Both 2132 and 2134 are FET input, it's almost the same chip, the OPA2134 being of lower grade but good enough for audio and cheaper. The OPA2132PA and OPA2134PA almost don't differ, the OPA2132P seems to be better than both, so as you can see, there is now high grade "P" series for the OPA2134, either. 

 FET inputs are intended for high impedance sources so for I/V stages they are OK but you can also use some low input bias current bipolar op-amps. Just see the specs._

 

Thanks for this, I will consider when selecting opamps.
 Is there any recommended type for the buffer or I can use the ones suggested for the I/V too?


----------



## isleofgeorge

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_To be a little provocative: I thoght we had reached a consensus. OPA2132/2134 is suboptimal for audio. There are better newer chips and there are better pricier chips._

 

Beeing a newbee I will still try them 
	

	
	
		
		

		
		
	


	




, since taste varies and the opinions I've red don't reflect that.


----------



## 12Bass

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I had a late one last night as I didn't want to stop listening with the OPA827's 
	

	
	
		
		

		
		
	


	




 Man, these are awesome opamps. More listening required to know where they fit in my list, I think it might be another late one tonight 
	

	
	
		
		

		
		
	


	


_

 

Will be interesting to hear your impressions over time. 

 Not sure exactly how I would characterize the OPA827, perhaps fairly neutral and detailed, not harsh, and smooth throughout. At first I found it lacking in "excitement", but came to appreciate its musicality after more in-depth listening.

 Regarding the OPA2132/34, in my applications, I've consistently preferred the OPA2132... sounds more detailed and natural to me, although still a bit veiled compared to the more neutral OPA827, which I find adds less noticeable coloration. I've found the OPA2134 to exhibit an odd coloration in the high frequencies, sort of a "phasey" sound, like they are out of focus or something....


----------



## diditmyself

Quote:


  Originally Posted by *Mr. Invisible Man* /img/forum/go_quote.gif 
_






_

 

OPA213x and passive ground? Earthy brown and ocher sounding? In that aspect the sound is "natural", but in my oppinion it's not neutral, not 3D and not detailed. Compared to OPA627 or even OPA2107 there's nothing good to say about it other than cheap and easy to find.

 Sound is personal for sure. My favorite at the moment is AD8599 as L/R and LM6171 as ground, no buffers. To my ears AD8599 is an LME49720 with soul, but as I understand it not many here like it.


----------



## diditmyself

Quote:


  Originally Posted by *isleofgeorge* /img/forum/go_quote.gif 
_Beeing a newbee I will still try them 
	

	
	
		
		

		
		
	


	




, since taste varies and the opinions I've red don't reflect that._

 

The impact of Andrea is masive since he writes under so many names and keeps repeating himself. Other than by him, I don't think OPA2132 or OPA2134are highly regarded. Opams come and go as fashion, and there's a steady progress. Not long ago people thought AD8620 or even OPA823 were as good as it gets, which they're not especially the latter.


----------



## isleofgeorge

One of the reason I'm gona try the opa213x, because it is easy and cheap to buy here. I will be replacing the stock opamps on the essence card and wanna see if there is any improvement with minimal cost. 
 I can get more advanced ones here as well or from overseas, but the next "level" cost 3-4 times more the least. 
 If I stick the most recommended one in straight away, than where would be the joy of experimenting the possibilities available with the wide range of opamps?
 If opamps come and go like fashion, than one which is not regarded now could have been (highly) regarded some time ago (like ad8620). I don't have the experience, so I might be happy with it till (if I) try another one later.


----------



## ROBSCIX

Not so much as fads or fashion. People talk about many and find ones they really like. Further testing my reveal issues with the siganture they don't like and move on to something else. 
 Only your ears can make the final decision.


----------



## LingLing1337

Can anyone recommend

 1) High-current opamps (I already have JRC4556) for my SR225i
 2) Opamps that can drive a heavy load (600 Ohm K240DF that I may be trading for)


----------



## Slash47

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_Can anyone recommend

 1) High-current opamps (I already have JRC4556) for my SR225i
 2) Opamps that can drive a heavy load (600 Ohm K240DF that I may be trading for)_

 

AD8397, but only up to +-12V. (Dunno what voltage the Beresford uses?)


----------



## leeperry

well, I haven't been able to locate any high quality multimeter...but I've set another cheap one to DC, and whatever on 200mv or 2000mv, it still reads 0.

 but I've been rolling these 1364 quite a lot, and they arrived completely crushed(thank you LT!) as they always pack the chips w/o ANY care whatsoever. I think someone in this thread mentioned the same kind of crackling problems on some poorly packet LT chips(that needed some heavy pliers job to be fixed).

 BTW, a friend of mine w/ an STX also tried the 2*LT1364>OPA2132P and he's most delighted, he runs a RSA Hornet to a JVC DX1k...so we just ordered some Audio GD Earth, 22 bucks a pop including shipping and extension cord...they will replace the OPA2132P 
	

	
	
		
		

		
		
	


	




 the way I see it, the LT1364 is only begging for polishing...the OPA2132P does it very well, w/ its very sexy mids and deep low end bass response. we're curious of hearing what the Earth will make of it 
	

	
	
		
		

		
		
	


	




 BTW, Slash, do you know where I can easily plug the ground of the Earth on the HD2 please? and on the STX for that matter.


----------



## Slash47

Your pc case perhaps? A bit ghetto, but whatever.


----------



## leeperry

no can do, I've just removed the backplate of the soundcard. 
	

	
	
		
		

		
		
	


	




 and I've removed all the heatsinks I had added to the op-amps/DAC/clocks....if Chomerics sells some ceramic heatsinks for EMI sensitive parts, that prolly means that using metal heatsinks is a big no-no 
	

	
	
		
		

		
		
	


	




*PS:* maybe I'll just pinch it in one of the screws that's supposed to hold the backplate


----------



## crapback

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_That's good to know. I was planning on trying a pair of those to replace my current OPA2134 (as voltage amplifier stage). What's holding me back is first saving to replace the ultra-cheapo pot with a quality attenuator. I think that's the weak point at the moment. I've pretty much tamed the noise on the power rails, so that will leave op amp substitution for the final tuning._

 

You could always try one of these. DACT Type 21 Stepped Attenuator Potentiometer 100K 2A3 - eBay (item 120471954152 end time Sep-27-09 14:56:18 PDT)

 I put one in my frankenwereferatu zero and it's pretty sweet. It was a pain in the arse to solder though. If you have to solder it straight to a board, whatever you attach as pins like to come off when you heat them up to solder them to the board.

 leeperry, do you have any mobo screws near the card? As for your DC worries, couldn't you add some bypass caps to the card? That might help to clean up some other noise from the rest of your compy too.


----------



## leeperry

yeah Slash told me I'd be better off adding some caps on top of the DIP8 sockets soldering points...I could ask a friend, but this would void warranty.

 and I don't think I'm getting any DC...Slash, did you ever measure that on the 1364+HD2? I'm sure you did 
	

	
	
		
		

		
		
	


	




 anyway, I love the 1364 vocals/SS and the 2132 extremely detailed mids/deep low end bass....the op-amp odyssey has come to an end for me.

 I'll try the 1028/1363, even though I think browndog's are worthless in a PC case due to EMI...still very eager to replace the 2132 by the Earth, which is 100% identical to the old Burson.

 if you look at the Burson site, all the raving comments were for the old chip: Burson Opamp


----------



## murrays

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_You could always try one of these. (link snipped) DACT Type 21 Stepped Attenuator Potentiometer. 
 I put one in my frankenwereferatu zero and it's pretty sweet. It was a pain in the arse to solder though. If you have to solder it straight to a board, whatever you attach as pins like to come off when you heat them up to solder them to the board._

 

Yes, exactly! A DACT is what I am planning on. It will fit because I left just enough room in my small desktop case when I built it. It's good to know that it'll be sweet. I am hoping that it will give the clarity to discern the subtle differences between op amps when I start swapping them. I have an older "reference" amp that will remain unchanged for comparison purposes.


----------



## crapback

You said you had to save up some money so I figured a $17US stepper w/shipping might fit the bill. The description on that ebay listing is pretty accurate if you ask me. The improvements were far more drastic than I expected. When gigawork says pinpoint imaging he isn't kidding. My zero has such sparkly clear highs now I could almost cry. I'm really, really tempted to put the other one I have in my new compass, but I think I'll wait till the warranty is up before I tinker with it.


----------



## diditmyself

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_Can anyone recommend

 1) High-current opamps (I already have JRC4556) for my SR225i
 2) Opamps that can drive a heavy load (600 Ohm K240DF that I may be trading for)_

 

600 Ohm is not a heavy load. Any of the opamps discussed in this thread can drive it. The problem is driving 30 or 16 Ohm loads.


----------



## leeperry

from Kingwa: "One year ago we made a lot OPA for one oversea manufacturer.
 Our OPA is same with Burson's, but we adjust the parameter can work well for most circuits."


----------



## crapback

I hope your sound card is capable of supplying the power an opa earth needs, leeperry. Kingwa told me that the earth draws 5 times more power than common chip opamps and runs at about 45 degrees C.


----------



## leeperry

well, if it doesn't...what gonna happen? 
	

	
	
		
		

		
		
	


	




 both the stock STX and HD2 seem fully capable of running them, even Slash47 puts 3 burson's: http://www.head-fi.org/forums/5904208-post1.html


----------



## crapback

Good thing then. I think you'll really enjoy the opa earth. I have a ridiculous collection of chip opamps now that I had lots of fun rolling for a couple weeks. Even the best combos of chips I tried still didn't have the smoothness that the opa earth does. I wouldn't be surprised if you want to invest in a couple more hdams after you try the earth.


----------



## leeperry

well, Slash told me that they are not more detailed...than say the 1364...I wanna keep the 1364 vocal grain anyway, but embelishing it w/ an Earth sounds thrilling


----------



## Slash47

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well, Slash told me that they are not more detailed...than say the 1364...I wanna keep the 1364 vocal grain anyway, but embelishing it w/ an Earth sounds thrilling 
	

	
	
		
		

		
		
	


	


_

 

Hi,

 That old pic really has to go. It's dated.

 Anyway, the DC offset on a stock card with LT1364 and a LT1361 is like 17mV-ish from the line out and pretty much zero from hp out.


----------



## leeperry

well the pic is on your website, kill it 
	

	
	
		
		

		
		
	


	




 ok thanks for the confirmation!


----------



## Slash47

Holy crap, you're right. DIE!


----------



## leeperry

you may also wanna add a dummy index.htm 
	

	
	
		
		

		
		
	


	




Index of /media


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_Good thing then. I think you'll really enjoy the opa earth. I have a ridiculous collection of chip opamps now that I had lots of fun rolling for a couple weeks. Even the best combos of chips I tried still didn't have the smoothness that the opa earth does. I wouldn't be surprised if you want to invest in a couple more hdams after you try the earth. 
	

	
	
		
		

		
		
	


	


_

 

I have been testing the discretes for quite awhile using various circuits and I agree the OPA-Earth is very smooth and neutral. I find it gets rid of the edge that some circuits can have when using chip opamps. 
 I have also been working with a custom discrete.....very nice


----------



## leeperry

Kingwa has also confirmed that he's not making the new burson, only the old one: _"Since July of 2008 we don't make OEM for any manufacturer. I never compare Burson's new OPA, I don't think I have this necessary. EARTH sound near neutral, SUN sound dynamic, MOON sound a bit tube like, which can suit you is depend on your taste."_

 I think Earth is cool, all the raving feedback from the old burson applies...and I'll take neutral over dynamic or tuby I think.


----------



## crapback

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I have been testing the discretes for quite awhile using various circuits and I agree the OPA-Earth is very smooth and neutral. I find it gets rid of the edge that some circuits can have when using chip opamps. 
 I have also been working with a custom discrete.....very nice
	

	
	
		
		

		
		
	


	


_

 


 Of which custom discrete is it you speak? Wow, I didn't end that sentence with a preposition. 
	

	
	
		
		

		
		
	


	




 Seriously though, can you provide any details or is it something in the works?


 Since I did a crappy job of keeping track of which opamps I ordered, I now have 12, yes 12 827's arriving tuesday.


----------



## ROBSCIX

I will see what I can do about information on the discrete. I will send you info if I can.

 I have a bunch of units I need to solder up, including the OPA827's.. I really enjoyed those when I initially tested them but they were for an associate. These new ones are built for my collection. If you have too many 827's you can send me a few if you want


----------



## SpudHarris

On that note......

 I have spent the weekend with the OPA827's in L/R of my P3+. I had to mess about with buffers and ground/V.ground to begin with but settled with Buf634's (Hi-C) and LME49710's (not the HA's). All I can say at this stage is that they are really, really beautiful Opamps. It's weird because warmer sounding opamps to my ears seem to miss certain details which is why I personally would describe an opamp as warm or tube like, these however seem warm but still have clarity and resolution in spades. In my set up they are not a nuetral sounding opamp but they are the best I've heard for a long while.

 I've given up on the LT1363's as the scratching of the volume pot (poss DC offset) was really bugging me, it was noticeable even with music playing and I feared for my earphones. So my top choices are OPA827's / AD797's biased to class A and OPA132UA's. I haven't tried the 827's in class A yet and didn't like the 132's in class A at all.


----------



## igor0203

Can you tell me how to push opamp in class A? I put 10k resistor between V- and which out? A or B? I have LT1364


----------



## Slash47

Both.

 10k from V- to out A and 10k from V- to out B


----------



## igor0203

Thanks!


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_On that note......

 I have spent the weekend with the OPA827's in L/R of my P3+. I had to mess about with buffers and ground/V.ground to begin with but settled with Buf634's (Hi-C) and LME49710's (not the HA's). All I can say at this stage is that they are really, really beautiful Opamps. It's weird because warmer sounding opamps to my ears seem to miss certain details which is why I personally would describe an opamp as warm or tube like, these however seem warm but still have clarity and resolution in spades. In my set up they are not a nuetral sounding opamp but they are the best I've heard for a long while.

 I've given up on the LT1363's as the scratching of the volume pot (poss DC offset) was really bugging me, it was noticeable even with music playing and I feared for my earphones. So my top choices are OPA827's / AD797's biased to class A and OPA132UA's. I haven't tried the 827's in class A yet and didn't like the 132's in class A at all._

 

What about Class A bias on the OPA827?


----------



## igor0203

F'cking amazing!


----------



## ROBSCIX

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_F'cking amazing! 
	

	
	
		
		

		
		
	


	


_

 

You like the sound of the Class A biasing?


----------



## LuciferX

I need help with linear technology samples, they never send me anything buy now in my email inbox i have this message:

  Code:


```
[left]We have received your sample request as below. The approval is not automatic for countries in South América. In order to approve your request the following information must be fullfilled. Pls note that information not received in 2 days, the sample request will be canceled. SAMPLE APPROVAL ORDER FORM Request ID:2101752 Customer Information Customer name: Address: Purchase contact: E-mail/Phone number: Engineering contact: E-mail/Phone number: [b]Fedex number: Pls note that the international freight as well as all import and other taxes applied by local governments will be customer responsibility.[/b] Project Information Project Name: Prototype date: Production date: Application: Estimated Annual Volume 1st year: Estimated Annual Volume 2nd year: P/N: Qty per board: Target US$:[/left]
```

So .... I have to pay for free samples !?!?!?


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_What about Class A bias on the OPA827?_

 

Like I said I've not tried that yet. Maybe when I've completely got used to the sound as they are I'll give it a go so I've got something to compare.


----------



## igor0203

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_You like the sound of the Class A biasing?
	

	
	
		
		

		
		
	


	


_

 

Yup, it's awesome. It's whole new sound dimension. 
	

	
	
		
		

		
		
	


	



 What do you use for opamp cooling?


----------



## leeperry

Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_So .... I have to pay for free samples !?!?!? 
	

	
	
		
		

		
		
	


	


_

 

they pack them very poorly anyway, try your luck on ebay maybe? LT1364CN (LT1364) Dual and Quad 70MHz Op Amp IC - eBay (item 110333253654 end time Oct-29-09 19:25:27 PDT)


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Like I said I've not tried that yet. Maybe when I've completely got used to the sound as they are I'll give it a go so I've got something to compare._

 

Just curious as I know you like to test with biased opamps. I like the OPA827's also. Have a bunch more here to solder up soon. Might do it here today...always soldering. I have ot get more Cardas Quad also running low.


----------



## ROBSCIX

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_Yup, it's awesome. It's whole new sound dimension. 
	

	
	
		
		

		
		
	


	



 What do you use for opamp cooling?_

 

You notice a big difference from the unmodded unit?


----------



## igor0203

Well not really a BIG difference but it's noticeable. I found that bass is little more refined and controlled, vocals are little bit more "liquid" if you know what I mean. Generally, sound is more musical.


----------



## LuciferX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_they pack them very poorly anyway, try your luck on ebay maybe? LT1364CN (LT1364) Dual and Quad 70MHz Op Amp IC - eBay (item 110333253654 end time Oct-29-09 19:25:27 PDT)_

 

Are they original?

 Anyway, i accept donations


----------



## leeperry

I dunno, I just found the link on ebay...too bad LT won't ship for free to SA...no idea why.

 so how's the bass on the OPA Earth anyway? I've just watched a couple of lossless movies w/ my combo...and I still get the same feeling as I originally had w/ the 1364(w/o the 2132P on top at the time), it just sounds VERY natural, not whiney, not bass heavy...just "spot on" as if you were in the damn street hearing traffic around you. LT wasn't lying when they told me it was a top choice for audio, w/ distortion so low that they had troubles measuring it.

 of course madVR w/ gamut conversion/perfect D65 colorimetry on a big projection screen in Reclock'ed 24Hz helps! but I dunno, it's hard to describe...it's both fulfilling and at the same time keeps me craving for more. maybe that's how you feel when you get perfectly natural sounding audio, maybe I should have ordered an OPA Moon


----------



## ROBSCIX

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_Well not really a BIG difference but it's noticeable. I found that bass is little more refined and controlled, vocals are little bit more "liquid" if you know what I mean. Generally, sound is more musical._

 

Hopefully I will get some modules made this week. I have quite a few units I want to bias to class A to see if there is any improvements to be had.
 Shall post my opinions when I get done with testing.


----------



## LuciferX

I need something comparable with the LT1364 but from TI or National (LT dislikes SouthAmericans ...), any ideas? I have 4 OPA2132, and some opamps for LM (4562,49860NA, 49720NA), and the 4 4580(JRC) from my Claro Halo. My idea is to test my current setup (4 x 4580) with some high quality combo like leeperry has


----------



## ROBSCIX

Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_I need something comparable with the LT1364 but from TI or National (LT dislikes SouthAmericans ...), any ideas? I have 4 OPA2132, and some opamps for LM (4562,49860NA, 49720NA), and the 4 4580(JRC) from my Claro Halo. My idea is to test my current setup (4 x 4580) with some high quality combo like leeperry has _

 

Some like the LT1364 and some don't, some like the 2132 and some don't.
 Try what you have to hear what sounds the best with your card, gear and ears. Personally, based on testing I wouldn't call the LT1364 and opa2132 a high quality combo. To each their own though..


----------



## leeperry

Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_I need something comparable with the LT1364 but from TI or National (LT dislikes SouthAmericans ...), any ideas? I have 4 OPA2132, and some opamps for LM (4562,49860NA, 49720NA), and the 4 4580(JRC) from my Claro Halo._

 

tried 4x2132 or 2x4580+2x2132? see if you like the LME sound for more than a day, I don't. the LT1364 is well worth the small investment IMO.


----------



## ROBSCIX

That is funny you say that now as you were one of the main gushers about the LME's. Telling everybody how great they sounded -even when you weren't being asked. It was much longer then a day also...more like a couple months
	

	
	
		
		

		
		
	


	




 Look back through the STX/St threads that should jog your memory...


----------



## crapback

LOL, i remember that ROB. Ah, the long journey through the sea of opamps. This thread was a little crazy there when everyone got into that crazy rush of sample-mania. 
	

	
	
		
		

		
		
	


	




 Also, I did get 12 OPA827AID's today. Tomorrow I'll have to throw them on some browndogs and give 'em a test drive. I love the sound of my zero right now so it'll be interesting to hear some chips again. Russian K40-Y9's make really sweet bypass caps. 
	

	
	
		
		

		
		
	


	





 I've been meaning to put a pic of my zero with the three earth's crammed in there. I had to cob up some insulators out of the plastic packaging from my weller desolder pump.


----------



## ROBSCIX

I have to build some more 827's soon. One thing about those discrete is they are hard to position, even worse for soundcards. More testing, more testing....


----------



## _Dejan_

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_they pack them very poorly anyway, try your luck on ebay maybe? LT1364CN (LT1364) Dual and Quad 70MHz Op Amp IC - eBay (item 110333253654 end time Oct-29-09 19:25:27 PDT)_

 

Yes when Im receive my OPAMP's they all have legs "curved"... They put OPAMP's only in static bag(not in any plastic or other thing to protect it) and in envelope...


----------



## crapback

TI doesn't mess around when they send out opamps. Apparently they don't have any smaller boxes. 
	

	
	
		
		

		
		
	


	




 LOL. I didn't realize that image was upside down.


----------



## _Dejan_

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_TI doesn't mess around when they send out opamps. Apparently they don't have any smaller boxes. 
	

	
	
		
		

		
		
	


	




 LOL. I didn't realize that image was upside down._

 

I must test my OPA827AID too, which Im receive few days ago...


----------



## crapback

Ok, here are my initial impressions of the opa827aid's in my modded '09 zero. So far I'm only comparing them to my audio-gd opa earth's that I have in the dac and amp sections.

 I like them. They are a good sounding opamp, period. Good detail over the whole frequency range. More bass than I remember with the 627's, but I can't find that module right now. 
	

	
	
		
		

		
		
	


	




 The mids are more pronounced than the hdams. The highs are pretty smooth and don't have that "digital" sound.

 I do like them but not more than my hdams. The biggest difference I've noticed so far is dynamics. The 827's don't seem to change levels as well as the earths. The volume of certain instruments, like Alex Lifeson's acoustic guitar work on Rush's "Natural Science" stays more constant with the 827's. I guess I would say that they sound a little compressed compared to the earths.

 Time to sit back and delve deeper into my music collection and see what else the 827's have to offer.


----------



## diditmyself

Anyone willing to sell some OPA827's?


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_Ok, here are my initial impressions of the opa827aid's in my modded '09 zero. So far I'm only comparing them to my audio-gd opa earth's that I have in the dac and amp sections.

 I like them. They are a good sounding opamp, period. Good detail over the whole frequency range. More bass than I remember with the 627's, but I can't find that module right now. 
	

	
	
		
		

		
		
	


	




 The mids are more pronounced than the hdams. The highs are pretty smooth and don't have that "digital" sound.

 I do like them but not more than my hdams. The biggest difference I've noticed so far is dynamics. The 827's don't seem to change levels as well as the earths. The volume of certain instruments, like Alex Lifeson's acoustic guitar work on Rush's "Natural Science" stays more constant with the 827's. I guess I would say that they sound a little compressed compared to the earths.

 Time to sit back and delve deeper into my music collection and see what else the 827's have to offer. 
	

	
	
		
		

		
		
	


	


_

 

I was impressed with the OPA827's when I initially tested them. Your right about sound I find many opamp chips can have a more "compressed" sound in comparison to the Earth HDAM's. The circuit would also be a factor ofcourse. I want to try the OPA827's biased to class A. I have to wait until my next parts shipment comes in though. I am design some new adapters with Class A bias in mind. Possibly with a place for a resisitor or other part or maybe even a trimmer. Will have to try it all out and make up my mind from there...


----------



## SpudHarris

I still have the 827's in my P3+ and I love em' 
	

	
	
		
		

		
			





. I've tried them biased to class A and as with the 49710HA's I didn't like them with this trick, they seemed too airy and lacking body or depth. I'm a little confused now about the class A trick as I noticed an earlier post with 2 x 10k resistors (I only use a 2.2k between pins 6 & 7).

 Anyhow with the 49710HA's in G/VG and Hi-C Buf634's the OPA827's will take some beating.....


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I still have the 827's in my P3+ and I love em' 
	

	
	
		
		

		
		
	


	




. I've tried them biased to class A and as with the 49710HA's I didn't like them with this trick, they seemed too airy and lacking body or depth. I'm a little confused now about the class A trick as I noticed an earlier post with 2 x 10k resistors (I only use a 2.2k between pins 6 & 7).

 Anyhow with the 49710HA's in G/VG and Hi-C Buf634's the OPA827's will take some beating....._

 

The circuit would be a factor also as would your phones/speakers. I want to try it just for the sake of testing and searching for better sound. A buddy sent me a couple Buf634's.. when you say HI-C Is that a mod your talking about?- I don't know too much about those units or any mods that involve them. I have yet to research about them...card to enlighten me?


----------



## crapback

Do any of you guys have an IR thermometer to check the temps of your gear? My 827's were running at around 45C which is as hot as my opa earths are supposed to run. I know that's well within specs for those chips but I would expect them to run much cooler than discrete opamps. It has me wondering if there is some oscillation occurring that I can't hear. If that's the case I'd really like to find out how to stop that and retest them again.


----------



## ROBSCIX

All IC generate some heat. Opamps can generate quite a bit and still be operating within proper specs Also depends greatly on what they are doing in the circuit.
 Usually when they are oscillating they draw way too much current and they get very hot. Can you leave your finger on them for awhile? You can figure out the current draw and then compare the paper value with the actual measured value. Aside from that you can use a scope... There are a couple good pages about working with opamps that are touchy. Usually fixing the oscillation requires adding caps...This page may help, Working with Cranky Opamps
 Let me know how it goes..


----------



## 12Bass

Don't recall the OPA827s being overly hot, and nothing approaching an AD8397 running at 24V. Could be unstable. Any capacitor bypassing on or across the power pins?


----------



## crapback

No bypassing of the opamp. I just don't know what temp the 827 should be operating at. According to the specs it can operate between -40C and +125C so a reading of 45C is about right in the middle. I'd think that's right where it should be but Kingwa told me that his hdams draw about 5 times the power of chip opamps and they run at 45C also. I have no problem holding my finger on them as that's only about 115F. 

 I've been a bit OCD about electronics temps since I sent an athlon1700 to an early grave. I just wanted to know if anyone else had taken any temp readings. The 827's won't be replacing my hdams so it's not important anyway. 
	

	
	
		
		

		
		
	


	




 Speaking of hdams, rolling some 827's got me comparing stuff again so I spent a little more time with the opa moon and I think I'll be keeping that in the dac of my zero for a while.


----------



## leeperry

ok I see Kingwa didn't ship my Earth yet, I've asked if I can get some Moon on top...you only live once 
	

	
	
		
		

		
		
	


	




 tomorrow I might try to swap my OPA2132 for an OPA827, but well an HDAM will be doing the final buffer anyway...the only real questions are :
 -Moon or Earth(300H of burn-in yiiiiikes)
 -will 1028 sound better than 1364 on vocals? I kinda doubt it.


----------



## murrays

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I'm a little confused now about the class A trick as I noticed an earlier post with 2 x 10k resistors (I only use a 2.2k between pins 6 & 7)._

 

Dual op amps need 2 resistors - one on each output. The resistor value differs according to voltage rail and desired bias current. A constant current source is supposed to give better results (see Tangent's article). I found out recently that all the op amps in my old Adcom DAC have a CCS on each output. So I've been unknowingly listening to biased op amps all along!


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_The circuit would be a factor also as would your phones/speakers. I want to try it just for the sake of testing and searching for better sound. A buddy sent me a couple Buf634's.. when you say HI-C Is that a mod your talking about?- I don't know too much about those units or any mods that involve them. I have yet to research about them...card to enlighten me?_

 

Hi-C is just another trick with a 220ohm resistor between pins 1 & 4. It is one of those tweaks that costs next to nothing but has quite a large effect on SQ. Only problem with portable amps though is running Buf's in Hi-C runs the batteries down quicker.

 I posted some pics earlier, give it a go you'll be amazed what a difference it makes.


----------



## diditmyself

OPA827 draws 5 mA quiescent. At higher voltage supplies it should be a little warm but not steaming hot. At what voltage supply is your OPA827 held?

 Regarding "working with cranky opamps", it's not recommended for JFET input opamps, and I don't like the concept of those high resistor values for bipolar opamps either and this is why: http://www.head-fi.org/forums/f6/ad-...ml#post6099224

 Regarding class A biasing of opamps, it's more elegant to use a JFET since the dynamic impedance is negligible and the current is kept constant, but... think of it, what load does the opamp in front of a buffer "see", almost nothing, several 100's of kOhm and most often low capacitance. It's different when it's driving MOSFETs, like in M3. I used to class A bias opamps, but then I listened blind and biased it live/while playing, and I couldn't hear any difference. When you notice any difference, is that difference to the better or just different, and are you sure the difference is really there?


----------



## SpudHarris

Well I have noticed positive differences in Opamps such as AD744, AD797 and the DIP version of LME49710's when biased to Class A. That said, there have been negative effects IMO on the OPA132's and OPA827's.

 At the moment I only have my buffers in Hi-C and have no other Opamps in my P3+ biased. My current chip set ticks all the boxes at the moment, I have even gone back to the AD797's in L/R but prefer the OPA827's 
	

	
	
		
		

		
		
	


	




 The P3+ runs on 6AA 1.5v Batteries or a 9v mains adapter so that's whats powering OPA827's in L/R - Buf634's (Hi-C) - LME49710HA's in G/VG.


----------



## 12Bass

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I have spent the weekend with the OPA827's in L/R of my P3+. I had to mess about with buffers and ground/V.ground to begin with but settled with Buf634's (Hi-C) and LME49710's (not the HA's). All I can say at this stage is that they are really, really beautiful Opamps. It's weird because warmer sounding opamps to my ears seem to miss certain details which is why I personally would describe an opamp as warm or tube like, these however seem warm but still have clarity and resolution in spades. In my set up they are not a nuetral sounding opamp but they are the best I've heard for a long while._

 

This sounds similar to my impressions. Initially, I found the OPA827 a bit on the warm and bland side.... then I listened a little more and found it was smooth throughout the midrange, had fullness in the lows, yet retained clarity and detail, not veiled like other "warm" op amps. Definitely better than the OPA2132, IMO.


----------



## SpudHarris

The only thing that has changed in my set up since posting that is that I use the 49710HA's now in G/VG. I didn't like them when I wrote that because they were biased to class A, I've since taken the resistors off the HA's and much prefer them that way. In G/VG they really bring detail and depth to the party.


----------



## 12Bass

Hmmm.... I'm not convinced about "class A" biasing op amps, largely because modern op amps are already highly optimized, making biasing a questionable practice. Then again, I haven't tried it yet... so perhaps one of these days I'll mess around with it and see if there's any difference/improvement. I'm a bit concerned about the practice, however, as a number of my circuits are DC coupled, and I suspect that adding bias may produce DC offset at the output.

 Any thoughts on the LME49710HAs compared with the AD827s?

 Planning on getting some OPA132UAs in the near future to see if they are really as good as some here claim, as well as OPA1612s. Still have AD797, ADA4898-1, and some others I can't remember at the moment to test....


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Hmmm.... I'm not convinced about "class A" biasing op amps, largely because modern op amps are already highly optimized, making biasing a questionable practice. Then again, I haven't tried it yet... so perhaps one of these days I'll mess around with it and see if there's any difference/improvement. I'm a bit concerned about the practice, however, as a number of my circuits are DC coupled, and I suspect that adding bias may produce DC offset at the output.

 Any thoughts on the LME49710HAs compared with the AD827s?

 Planning on getting some OPA132UAs in the near future to see if they are really as good as some here claim, as well as OPA1612s. Still have AD797, ADA4898-1, and some others I can't remember at the moment to test...._

 

If I had to choose I would still take the 710HA module. However, maybe I will do some direct comparisons here today. I also have some OPA132's to try out, as I want to try the single channel version over the 2132. You reminded me I also have some 1611's to build. I have a pile of dual SOIC8 to dip 8 so I guess today is the day... I am also interested in the Class A mod just to check on the differences.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Hi-C is just another trick with a 220ohm resistor between pins 1 & 4. It is one of those tweaks that costs next to nothing but has quite a large effect on SQ. Only problem with portable amps though is running Buf's in Hi-C runs the batteries down quicker.

 I posted some pics earlier, give it a go you'll be amazed what a difference it makes._

 

Ah yes. When you linked to that pic I remember the conversation now.
 Thanks for the information, do you have any other mods you would like to mention?


----------



## diditmyself

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_I'm a bit concerned about the practice, however, as a number of my circuits are DC coupled, and I suspect that adding bias may produce DC offset at the output._

 

DC-offset isn't affected.


----------



## dlb0089

anybody here have an essence stx sound card? i was wondering what op amp configurations u guys like. i have been using stock LM4562NA buffer, as well as LM4562NA's in I/V until today i put my stock 2114D's back in due to a aggravating lack of bass with the LM4562NA's/ so i guess what i'm looking for is suggestions on something similar to the 2114D thats several rungs up the quality/clarity ladder. and if i could do better than stock buffer as well.

 my speakers are audioengine a5's. and headphones are markl modded denon d2000's

 thanks!


 EDIT: ive seen quite a few people on here that like the earth/moon/sun opamps. would that be a good direction to head in or could i do better?


----------



## leeperry

ok I've replaced the 2132P by the 827....it's very good so far! clearer trebles, still very good low end bass.

 I think I got bored of the 2132 sound...ah 
	

	
	
		
		

		
		
	


	




 but the forthcoming Moon/Earth will ditch it anyway


----------



## 12Bass

Maybe take some time to listen throughout the frequency range. What I noticed after extended listening to the OPA827s was a warm, yet clear and fluid, midrange.... sort of subtle, but musical, IMO.


----------



## leeperry

I've got a bunch of very well recorded classical tracks from Brahms...the kind you'd hear in the Looney Tunes cartoons, w/ Bugs Bunny doing ice skating 
	

	
	
		
		

		
		
	


	




 I loved how it sounded tubey on the 2132, the violins had a very emotional sound...but as majkel said about the OPA Moon, tubey has its limits 
	

	
	
		
		

		
		
	


	




 it sounds good for a while, then you get bored of always hearing the sound so much "colored".

 the same Brahms tracks on the OPA827 sound more "live"(the 1364 turns everything it touches into solid gold), and less colored...clearer, indeed 
	

	
	
		
		

		
		
	


	




 triangles seem even farther, indeed the SS is very wide and imaging is great...this is a solid chip so far!


----------



## SpudHarris

Seems as though we are pretty much all agreed, the OPA827 is indeed a fine Opamp. I only ordered 2 at the time so must get another few to try elsewhere.


----------



## leeperry

the upper spectrum is definitely less distorted and clearer/more detailed than on the 2132...but more fatiguing as well, OTOH the low end bass is still very much there but less bloated. imaging is great!


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Seems as though we are pretty much all agreed, the OPA827 is indeed a fine Opamp. I only ordered 2 at the time so must get another few to try elsewhere._

 

Yes for sure, they seem to have great sound in all our different circuit and applications. I am building 5 dual SOIC8 to DIP8 modules for use in my circuits.


----------



## SpudHarris

OK, I'm putting an order in for some more 827's. Can you guys recommend any other BB chips I should stick on my list?? BTW the TI site is sloooooooooow tonight taking forever for a single page to load. Already have 2107 - 132 - 2132/4 - 627/37 - 228.


----------



## ROBSCIX

How about OPA2227's they are great for bass. You seem to have a good list of BB's already.


----------



## 12Bass

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_OK, I'm putting an order in for some more 827's. Can you guys recommend any other BB chips I should stick on my list?? BTW the TI site is sloooooooooow tonight taking forever for a single page to load. Already have 2107 - 132 - 2132/4 - 627/37 - 228._

 

OPA1611/12, OPA211/2211A, OPA365/2365 for low voltage, and OPA2827 if/when it becomes available.


----------



## ROBSCIX

Sure the new 161X series is decent also..they were talked about awhile back.


----------



## LuciferX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_the upper spectrum is definitely less distorted and clearer/more detailed than on the 2132...but more fatiguing as well, OTOH the low end bass is still very much there but less bloated. imaging is great! 
	

	
	
		
		

		
		
	


	


_

 

Hahha you found a 2132 substitute, but i need a 1364 one !


----------



## SpudHarris

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_OPA1611/12, OPA211/2211A, OPA365/2365 for low voltage, and OPA2827 if/when it becomes available._

 

Thanks, yeah I got the 1611's and 211's. I will try 365's though. Unfortunately TI are asking awkward questions about me ordering more 827's (already had 2 off them) so I'm stumped.


----------



## leeperry

Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_Hahha you found a 2132 substitute, but i need a 1364 one ! 
	

	
	
		
		

		
			






_

 

I don't think it'd exist....find someone living outside SA, order some for them and get them shipped back or sumthing.

 anyway, the 827 is fantastic in binaural downmixed movies


----------



## leeperry

BTW, for ppl scared of DC leakage in the 136x...this might be an option: GROUND LOOP ISOLATOR WITH 3.5MM MINI EARPHONE PLUG JACK - eBay


----------



## leeperry

so everyone's stopped messing around? 
	

	
	
		
		

		
		
	


	




 I like how they describe the 1364 on this forum: Google Translate
  Quote:


 LT1364 is just like what you say and make a glossy or colored umbrella. Vocals is just out in front is just right. 
 

I'm tempted to try 4*OPA827 + 2*1028/1363...but the OPA Moon/Earth will replace the last buffer anyway, and I don't think any IC would crush them? so it boils down to 4*1363/1028 + 1*Moon/Earth I think 
	

	
	
		
		

		
		
	


	




 but 2*LT1364CN8(as DAC buffer)+2*OPA827AID(as final buffer) is a great combo anyway


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Seems as though we are pretty much all agreed, the OPA827 is indeed a fine Opamp. I only ordered 2 at the time so must get another few to try elsewhere._

 

I wanted to ask you more about the biasing of the 827's. What were your results? 
 You had mentioned you didn't like the results?
 Can you elaborate a bit more, what were you hearing when they were biased?
 I figured this procedure would be like anything else, would work great with some opamps yet might decrease the sound quality in other units.

 I am waiting for my new components shipment so I haven't been able to bias them for my own testing. Looking forward to testing though...


----------



## SpudHarris

Well I've found that the more modern Opamps don't benefit from this type of biasing, in fact I find that it has a negative effect on some, it has been noted that being so modern that they are Optimised for performance already and I tend to agree with this most of the time, there is certain types of distortion that can sound sweet or different in a good sense. However, the negative effect to my ears seems to be similar in most, the only way I can describe it is that music seems to lose a certain amount of body and resolution it becomes too airy, detail is there but seems far away. These are only my findings and they are based on my P3+ with lossless tunes and JH13's. By the way the OPA827's are still my weapon of choice, there is a definate synergie now with my JH13's (with Null Audion Enyo Silver Cable).


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well I've found that the more modern Opamps don't benefit from this type of biasing, in fact I find that it has a negative effect on some, it has been noted that being so modern that they are Optimised for performance already and I tend to agree with this most of the time, there is certain types of distortion that can sound sweet or different in a good sense. However, the negative effect to my ears seems to be similar in most, the only way I can describe it is that music seems to lose a certain amount of body and resolution it becomes too airy, detail is there but seems far away. These are only my findings and they are based on my P3+ with lossless tunes and JH13's. By the way the OPA827's are still my weapon of choice, there is a definate synergie now with my JH13's (with Null Audion Enyo Silver Cable)._

 

Yes, the 827's sounds pretty good from my tests. Actually, I have been testing them since their release as you probably have.
 Maybe the biasing would work better on older modules as you say the newer units offer different and more optimized circuits. I still want to do the testing but I will work with some of the older units.


----------



## leeperry

I'll see next week if OPA-Moon sounds as tubey as they say...but so far it does LOOK like it 
	

	
	
		
		

		
		
	


	




RightMark Audio Analyzer test: comparison

 comes from here: http://translate.google.com/translat...3Doff%26sa%3DG

 he confirms that sun v2 is bright and says that moon is blurry...


----------



## 12Bass

Finally got around to testing AD797, mostly comparing 2 x AD797ANZ (on BrownDog 021001) with 2 x OPA211 (on BrownDog 020302) and OPA2211A (on BrownDog 970601) and LM49722MA (soldered onto DIP socket). I was testing all of these parts in the output stage of my (highly modded) Eden Highwayman bass amplifier. The input section uses OPA827s and OPA211s. The EQ section was bypassed during testing. The preamp section employs +/- 16V power rails. 

 My quick impressions are that AD797 sounds relatively clean and neutral, though a bit darker than OPA211/2211A. It's a bit hard to describe, as it doesn't really sound veiled, just lacking in "sparkle" in the highs. Although I haven't done a proper comparison, I'd say that they are more neutral than the AD825 (which I initially liked, but later found a bit too colored, as they seemed to suck out the mids somewhat, boosting bass and treble). Sort of "clear and a bit dark" if that makes any sense.... 

 Although I didn't notice it in previous testing, I found that the pair of single OPA211s sounded somewhat clearer than the dual OPA2211A, which sounded somewhat more distant and less authoritative. Definitely prefer 2 x OPA211. 

 From a limited comparison, I found that the LM49722 is somewhat better than LM4562 (cleaner/less colored), though lacked some of the openness found in the OPA211/2211A. Maybe less sterile than LM4562, too. I do like the clarity of the midrange of the LM49722, however.

 Still have more listening to do with LME49860NA (which I listened to briefly), and ADA4898-1 (when new BrownDog adapters arrive). Quick impression was that LME49722 was superior to LME49860.

 From the charts above, it appears the the OPA-Moon generates a significant amount of harmonic distortion.... which might make it sound "tubey" to some....


----------



## ROBSCIX

@12bass, have you tried the LME49710HA yet?


----------



## leeperry

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_From the charts above, it appears the the OPA-Moon generates a significant amount of harmonic distortion.... which might make it sound "tubey" to some...._

 

well, if inexistent THD means LM49722'ish sound: whiney trebles, anemic bass, dull & wide SS....I'll take a "tubey" op-amp anytime of the day 
	

	
	
		
		

		
		
	


	




 apparently getting good bass response means getting harmonic distortion...tube amps have high distortion, yet they still seem to be unmatched for euphonic listening.

 but well, if I had seen these charts before I prolly wouldn't have ordered the Moon...OTOH my hopes towards the Earth(OEM version of the old burson) are rather high.


----------



## 12Bass

Have one LME49710NA here, but no HA of any kind. They were too pricey from Digi-Key last time I made an order. 

 Not sure about "whiney trebles".... that comment makes me wonder about possible instability in that particular application. I've found some of the LM/LME series to be a bit on the sterile side, but nothing I would describe as "whiney". Or maybe the vocabulary is different? 

 IMO, harmonic distortion is not necessary for good bass response.... if anything, it adds high frequency content over top of the fundamentals... though 2nd harmonic distortion might add some pleasing overtones and may sound thicker to some ears. Then again, I suspect that our tonal goals are different, as I tend to prefer transparency over euphonic coloration, and have found the OPA2132 too colored for my taste. 

 The circuit I'm using to test (in the Eden) is set up with low input impedance and a gain of 3-4, has supply bypassing, as well as 10 pF capacitors in the feedback loop, so it should be stable with most op amps.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Have one LME49710NA here, but no HA of any kind. They were too pricey from Digi-Key last time I made an order. 

 Not sure about "whiney trebles".... that comment makes me wonder about possible instability in that particular application. I've found some of the LM/LME series to be a bit on the sterile side, but nothing I would describe as "whiney". Or maybe the vocabulary is different? 

 IMO, harmonic distortion is not necessary for good bass response.... if anything, it adds high frequency content over top of the fundamentals... though 2nd harmonic distortion might add some pleasing overtones and may sound thicker to some ears. Then again, I suspect that our tonal goals are different, as I tend to prefer transparency over euphonic coloration, and have found the OPA2132 too colored for my taste. 

 The circuit I'm using to test (in the Eden) is set up with low input impedance and a gain of 3-4, has supply bypassing, as well as 10 pF capacitors in the feedback loop, so it should be stable with most op amps._

 

There are quite a few guys here now that are using the LME49710HA. The HA models sound different to me and to those that have tested.
 Not too many here have tested these, as in a dual channel application the adapters are not readily available.
 I am pretty sure the 710 is cheaper then the 720 from Digikey...
 I test lots of opamps though, seems like I am always testing something new or old...like most of the opamps collectors here. I just mentioning the 710HA as it gets overlooked by some and it is a great unit.
 I have made test units for associates and asked for their opinions and in every case they have been positive.

 As for your other testing, I have only tried the 211's. I like those ones personally.


----------



## leeperry

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_I've found some of the LM/LME series to be a bit on the sterile side, but nothing I would describe as "whiney"._

 

well I'm using headphones, and because of ear resonances I prolly need dark chips...the LME serie is very bright IME.


----------



## cravenz

not sure if I should ask this here, but I'm kinda looking for an opamp or topkit to pair with the iBasso D10s and my IE8s. 

 would anyone have any input? I've been told to look at HiFlight's AD8599s paired with AD8616 or the TLE2141 class-A


----------



## SpudHarris

That combo recommended by Hiflight would probably suit the SS of the IE8's but the TLE2141 even in class A is far from great (IMO), there are much better Opamps around. Your best bet is to get on the D10 rolling thread if you've not already been there or indeed the P3 / P3+ threads, there are some great recommendations there. Personally, I've been rolling and rolling and rolling and settled with the OPA827's in L/R. They are kinda warm which may not be the best pairing for the IE8's but that said they do have detail in spades also.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_That combo recommended by Hiflight would probably suit the SS of the IE8's but the TLE2141 even in class A is far from great (IMO), there are much better Opamps around. Your best bet is to get on the D10 rolling thread if you've not already been there or indeed the P3 / P3+ threads, there are some great recommendations there. Personally, I've been rolling and rolling and rolling and settled with the OPA827's in L/R. They are kinda warm which may not be the best pairing for the IE8's but that said they do have detail in spades also._

 

The 827 stopped the rolling for a bit?
 I agree, they are some great opamps based on my testing also.


----------



## Kuze

Must... stop... this... addiction!!!


----------



## kloan

Any recommendations for opamps suitable for UM3X?

 I just got a Shellbrook mini signature, has dual opamps. Currently, OPA227P are in it... I've tried 2 different headphones, both sound as though mids are slightly veiled. Bass is very prominent, and trebles are quite forward.

 I'm looking for some opamps that'll provide extensive, deep bass, good mids and tame treble, good detail, soundstage, etc.


----------



## leeperry

Quote:


  Originally Posted by *Kuze* /img/forum/go_quote.gif 
_Must... stop... this... addiction_

 

so, how good is the LT1208 anyway? I don't think it'd top the LT1364...but you never know


----------



## ROBSCIX

Quote:


  Originally Posted by *kloan* /img/forum/go_quote.gif 
_Any recommendations for opamps suitable for UM3X?

 I just got a Shellbrook mini signature, has dual opamps. Currently, OPA227P are in it... I've tried 2 different headphones, both sound as though mids are slightly veiled. Bass is very prominent, and trebles are quite forward.

 I'm looking for some opamps that'll provide extensive, deep bass, good mids and tame treble, good detail, soundstage, etc._

 

That opamp is known to have good bass but a bit light in the detail and clarity areas. I keep a few of those around for using in subwoofer channels on surround cards. If you like the sound of that series but need more detail and clarity go for a 2107. There are others also but that would be my choice to replace a 227.


----------



## 12Bass

Finally auditioned the THS4052 and found it more open sounding than the 2 x OPA211 on BrownDog adapter (although there's a capacitor right across the rails on the DIP socket, the THS part runs on the hot side). Still find the OPA211 to have a pleasing, somewhat warmer, tonality. I preferred both to the LM6172... not sure how to describe that one... not bad, not overly colored, just sort of "bland".... didn't hear the punchy sound that some have spoken about.

 Have a pair of ADA4898-1s, but am waiting for more adapters before I can test them. OPA1611s and OPA132UAs are also waiting for adapters, and OPA1612s haven't arrived yet.... curious to find out if they sound any better/different than OPA2211A. The documentation notes that the duals (OPA1612s) use completely separate circuitry, except the power rails, of course... not sure if that is true for OPA2211A as well, and just not mentioned, or what... as I noticed a definite improvement when using 2 x OPA211 over the dual package.


----------



## leeperry

well, I've been running the OPA827 for a few days....but I kinda miss the tubey sound of the 2132P 
	

	
	
		
		

		
		
	


	




 U87 vocals sound too clear/too clean, I like when they sound emotional...hopefully I'll get my Moon/Earth within a few days, these should embelish the LT1364 vocal grain beautifully


----------



## kloan

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_That opamp is known to have good bass but a bit light in the detail and clarity areas. I keep a few of those around for using in subwoofer channels on surround cards. If you like the sound of that series but need more detail and clarity go for a 2107. There are others also but that would be my choice to replace a 227._

 

Thanks for the recommendation.. just ordered a couple from HK.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Finally auditioned the THS4052 and found it more open sounding than the 2 x OPA211 on BrownDog adapter (although there's a capacitor right across the rails on the DIP socket, the THS part runs on the hot side). Still find the OPA211 to have a pleasing, somewhat warmer, tonality. I preferred both to the LM6172... not sure how to describe that one... not bad, not overly colored, just sort of "bland".... didn't hear the punchy sound that some have spoken about.

 Have a pair of ADA4898-1s, but am waiting for more adapters before I can test them. OPA1611s and OPA132UAs are also waiting for adapters, and OPA1612s haven't arrived yet.... curious to find out if they sound any better/different than OPA2211A. The documentation notes that the duals (OPA1612s) use completely separate circuitry, except the power rails, of course... not sure if that is true for OPA2211A as well, and just not mentioned, or what... as I noticed a definite improvement when using 2 x OPA211 over the dual package._

 

THS4052? -have you tested the THS403X series? Are they similar in signature?
 Did you add the cap? Did you have stability issues is this why you added it?
 Ah, you just reminded me, I have to put some 1612's on adapters also.


----------



## 12Bass

Have THS4032 as well... initially found it clear/punchy, but it seemed a bit lacking in body after a while, and I ended up preferring the seemingly more accurate midrange of the LM4562 (then later OPA211/OPA827). That one gets hot as well. The THS4052 under test is an SOIC soldered to a DIP socket with a 0.01 µF capacitor directly underneath soldered across the power pins. Even though I have bypassing in the circuit, I often mount bypass caps directly on high speed parts as a preventative measure. Although somewhat similar, from limited listening, I prefer the THS4052... sounds more neutral/less colored, with transparent highs... somewhat like AD797, but with the highs extending more effortlessly.


----------



## 12Bass

Note: I should mention that Jim Williams from Audio Upgrades has been responsible for a number of these op amp suggestions, particularly the high speed parts.


----------



## ROBSCIX

Audio upgrades, do you have the link to the site?
 I cannot say anything about the THS4052 just the THS4032, your bypassing the opamps as precaution and not because of a issue you had?
 Well I guess your saving time as many of these high speed units will osciallate.


----------



## leeperry

Jim Williams also said that LT1357 is the best op-amp..

 anyway, I like Kingwa's reply to these poor OPA-Moon THD measuremements: _"We are making the products for human's ears, not for the robot. Do you notice the tube amp, they have the bad test perfermance but some tube amp sound excellent."_


----------



## 12Bass

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_Jim Williams also said that LT1357 is the best op-amp._

 

From what I've gathered, he recommends a variety of op amps for different applications and tastes.... with a tendency to suggest modern/fast parts.


----------



## 12Bass

THS4052 soldered to DIP socket. This is a cheap alternative to BrownDog adapters. 






 0.01 µF capacitor across +V and -V (pins 4 and 8):


----------



## ROBSCIX

How does it sound?


----------



## 12Bass

This is an AD8397 in my Gina24's headphone circuit, replacing SSM2135. A number of bypass capacitors were used, two 2200 µF on the rails (+/- 12V), two 22 µF and two 0.01 µF on pins 4 and 8, plus one 0.01 µF across.

 The circuit looks messy largely because it has been modified too many times and traces have lifted, plus the AD8397 required some circuit changes in order to make things stable/reliable. That and my careless soldering....

 The Gina's headphone output with the AD8397 is clearer and more punchy sounding than with the original chip, which sounded sort of small and lifeless. Other mods are an OPA2211A in place of NJM2068 on the PCI card, along with shorted output capacitors, meaning that the output is DC coupled. This is my main source/headphone amp, used for driving my K702s.


----------



## 12Bass

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_How does it sound?_

 

If you're referring to THS4052, I made some comments here: http://www.head-fi.org/forums/f6/opa...ml#post6116238


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_If you're referring to THS4052, I made some comments here: http://www.head-fi.org/forums/f6/opa...ml#post6116238_

 

Yes, already seen that. Early morning with no Coffee


----------



## leeperry

humm, U87 vocals and violins sound miles better on the OPA2132P than on the OPA827 
	

	
	
		
		

		
		
	


	




 they sound more "holographic", warmer, livelier...involving, emotional. Clinical and low distortion is not always the best choice IMHO for euphonic listening 
	

	
	
		
		

		
		
	


	




*PS:* as Kingwa puts it _"I ever use OPA2132 at some years ago, it sound very good."_


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_





 This is an AD8397 in my Gina24's headphone circuit, replacing SSM2135. A number of bypass capacitors were used, two 2200 µF on the rails (+/- 12V), two 22 µF and two 0.01 µF on pins 4 and 8, plus one 0.01 µF across.

 The circuit looks messy largely because it has been modified too many times and traces have lifted, plus the AD8397 required some circuit changes in order to make things stable/reliable. That and my careless soldering....

 The Gina's headphone output with the AD8397 is clearer and more punchy sounding than with the original chip, which sounded sort of small and lifeless. Other mods are an OPA2211A in place of NJM2068 on the PCI card, along with shorted output capacitors, meaning that the output is DC coupled. This is my main source/headphone amp, used for driving my K702s._

 

If your planning on doing more work to this output, maybe go with a SOIC to DIP8 adapter and you could just install DIP8 modules. This would prevent all the soldering etc when trying out various units. Brown dog has a model that would work->LINK
 Solder down the SOIC side and solder in a DIP8 socket. They are kind of big but may be something you might want to check out.


----------



## 12Bass

Thanks ROBSCIX. 

 Actually, I'm pretty happy with the AD8397.... can't think of another chip which would be better for this application (driving low impedance headphones). Also don't like the idea of adding more mechanical connections from a reliability/stability perspective. The intention behind this particular circuit was to fabricate a reliable, good sounding, headphone output, not to mess around with op amps.... I have other circuits for that....


----------



## igor0203

I've got OPA827 today for testing. Will report when I'll install them. Currently I have LT1364 which I found to be the best so far.

 Here is schematic of amp I'm using 

http://www.shrani.si/f/2C/OV/1hAqJ18...0schematic.pdf


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Thanks ROBSCIX. 

 Actually, I'm pretty happy with the AD8397.... can't think of another chip which would be better for this application (driving low impedance headphones). Also don't like the idea of adding more mechanical connections from a reliability/stability perspective. The intention behind this particular circuit was to fabricate a reliable, good sounding, headphone output, not to mess around with op amps.... I have other circuits for that.... 
	

	
	
		
		

		
		
	


	


_

 

Sure, just a suggestion. Figured it might be easier then re-soldering new opamps in there. However, as you said, your not changing this one now.
 Just a thought.


----------



## leeperry

ouhhhh, Kingwa sure knows his business..will try Moon later today, but Earth is quite impressive so far 
	

	
	
		
		

		
		
	


	




 photos available here: http://www.head-fi.org/forums/6120046-post76.html


----------



## ROBSCIX

Yes. This is why they are suggested by many people around here.


----------



## leeperry

woohah...soundstage is just CRAZY in movies and lives concerts w/ the Earth...talking about SS w/o having heard discrete op-amps is like trying to explain music to a deaf-born person, it makes that much of a difference! 
	

	
	
		
		

		
		
	


	




 it's totally 3D, your brain can do his work at measuring delays and calculating distances in a totally natural way...full 180 degrees SS FTW!


----------



## leeperry

ahhh OPA-Moon sounds exactly like its RMAA measurements look, distorted to death 
	

	
	
		
		

		
		
	


	




 it feels like going from a top rate home CD player to a crappy FM car radio...major waste of $$$


----------



## ROBSCIX

The moon sounds great but like many opamps is not compatible with every circuit.
 Perhaps, simply asking questions and reading may have helped. If you had of asked anybody their opinion I would have told you the Moon can be unstable in many circuits. I am sure others would have mentioned it also...


----------



## 12Bass

Just looking at the photos, it is hard to imagine that running a bunch of long wires from a discrete op amp to a DIP socket can be helping performance any.... all sorts of inductance, RF pickup, and an open invitation for oscillation there.

 Just curious, leeperry, have you done any quasi-scientific testing, perhaps having a friend swap op amps so that you don't know which ones you are listening to? Expectation can have a huge impact on auditory perception.


----------



## leeperry

hehe, well the Earth sounds amazing...it really does, it's the same as the old burson(Kingwa was making it as OEM for them)...you can look up all the testimonials over the internet, it's not just in my head 
	

	
	
		
		

		
			





 anyway, time to ditch the Moon and put back the holy Earth again 
	

	
	
		
		

		
		
	


	




 next time I order, I'll be getting twice shorter extension leads indeed...it'll be less of a mess in my box, and maybe it'll also improve the SQ. anyway, I'm also getting a new burson w/ a mundorf cap, I wonder if it'll sound any better than the Earth


----------



## leeperry

yeah, one thing that's totally amazing on the Earth is the stereo coherence..just mind blowing!

 you can see at the end of their webpage that they give perfect waveforms on an oscilloscope, unlike IC's: ÐÂ½¨ÍøÒ³ 1

 another site did many more comparisons and came up w/ the same conclusions.

 It's funny seeing manufacturers like Denon boast about dual-ended headphones to keep the stereo coherence spot-on, when most ppl will be using crappy IC's w/ lousy stereo soundstage to begin with..my cd1k is single-ended and I've never heard stereo this accurately, it makes my brain sooooooo happy in TrueHD binaural downmixed movies 
	

	
	
		
		

		
		
	


	




 I'll try 3*Earth but I'll prolly miss the vocal magic of the LT1364...but ya never know


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Just looking at the photos, it is hard to imagine that running a bunch of long wires from a discrete op amp to a DIP socket can be helping performance any.... all sorts of inductance, RF pickup, and an open invitation for oscillation there.

 Just curious, leeperry, have you done any quasi-scientific testing, perhaps having a friend swap op amps so that you don't know which ones you are listening to? Expectation can have a huge impact on auditory perception._

 

Do you do any class A biasing work? just wondering if anybody has the proper formula for the bias resistors. I had it written down but cannot seem to find it. I am ordering about $100 in new parts for my opamps and want to get some biasing resistors.


----------



## Slash47

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Do you do any class A biasing work? just wondering if anybody has the proper formula for the bias resistors. I had it written down but cannot seem to find it. I am ordering about $100 in new parts for my opamps and want to get some biasing resistors._

 

Figure out your supply voltage, your load impedance and how much power your opamps can deliver. Don't go below 1k or above 20k, else it's pointless/harmful.

 If you're driving a buffer, 10k is plenty. If you're driving a headphone amp with 12k input impedance, go lower, like 3k3.

 2k2 is a good value because pretty much nothing has less then 10k load impedance (except for headphones and speakers, of course) and high bias gives sweeter results. However, some (modern) opamps seem to prefer the higher load impedance to the bias current. Others can have a hard time coping with the heavy load, resulting in a loss of dynamics or even clipping/distortion.


----------



## diditmyself

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Do you do any class A biasing work? just wondering if anybody has the proper formula for the bias resistors. I had it written down but cannot seem to find it. I am ordering about $100 in new parts for my opamps and want to get some biasing resistors._

 

You should use Ohm's law. R=U/I. A couple of mA is enough. Eg if the supply is +/- 10 V and you want 2 mA: R=10/0.002 => R=5k. I guess the recommended 2k2 or 3k3 is fine too.

 Consider using constant current sources instead, like a JFET with appropriate source resistor. Look at how it's done in PIMETA, PPA or M3. You don't _need_ cascoded JFETs.


----------



## igor0203

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_...it makes my brain sooooooo happy in TrueHD binaural downmixed movies..._

 

Can you name some, please?


----------



## leeperry

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_Can you name some, please?_

 

this one has a 24/48 TrueHD binaural track on BD: Bad Boy Bubby (1993)

 I usually make my own 3D-ish stereo downmixes in ffdshow+Ozone4...I'd say the most impressive lossless soundtracks I have would be Transformers II/Nightmare Before Xmas/Kill Bill 1, always impressed by those


----------



## leeperry

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_it is hard to imagine that running a bunch of long wires from a discrete op amp to a DIP socket can be helping performance any.... all sorts of inductance, RF pickup, and an open invitation for oscillation there._

 

_"We have added caps on the OPA, so it can reduce the effect of leads. -Kingwa"_

 I honestly can't hear any nasty artifacts, just some totally crazy stereo coherence..talk about surreal SS 
	

	
	
		
		

		
		
	


	




*PS: *hahaha, Andrea has gone discrete too?? would explain his silence 
	

	
	
		
		

		
		
	


	









  Quote:


 Hello, I'm Andrea from Italy. I purchased all of your discrete opamps, and after a 300+ hours or burn-in and deep listening I stick with the OPA Sun v2 as my favourite on my system (Zero DAC, Dussun DS99 amplifier, Tannoy Sensys DC2). I found it having the best dynamics and impulse response as you described it in your website, I feel it very fast and accurate, revealing a detail that the other two don't. I prefer the Sun v2 over the Earth under any aspect.


----------



## Cynips

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_*PS: *hahaha, Andrea has gone discrete too?? would explain his silence 
	

	
	
		
		

		
		
	


	








_

 

Why would that explain anything? Going discrete hasn't stopped you from coming here, has it?


----------



## leeperry

well, he went from 5 posts a day of "my favorite is this one, oh no this one...or maybe this one" to zero posts.

 maybe the man finally found his favorite, once and for all 
	

	
	
		
		

		
		
	


	




 but yeah, IC's don't hold a candle to discretes(mushy SS is the worst offender)...I've just ordered some SUN V2, maybe I'll like it more than Moon.

 I'm still waiting on my LT1028....but I'm rather doubtful these would crush discretes.


----------



## diditmyself

Now we just have to wait and see if he starts transistor rolling. SA970/SC2240 are kind of bright sounding, but on the other hand SK170/SJ74 are warm sounding and grainy when uncascoded.


----------



## leeperry

goodness gracious, this guy hacks standalone players...not to put discrete op-amps, but tubes!

Lampizator page index

sony227ESD


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_*PS: *hahaha, Andrea has gone discrete too?? would explain his silence 
	

	
	
		
		

		
		
	


	








_

 

When I had all 3 HDAMs, I too preferred the Sun V2. It was well suited to metal and progressive rock.


----------



## Pluto2

Andrea is happily residing on diyaudio these days..... : )


----------



## K3cT

Anymore Sun V2 to Earth comparison? The Sun is too bright for me now, considering selling it if it stays this way.


----------



## leeperry

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_When I had all 3 HDAMs, I too preferred the Sun V2. It was well suited to metal and progressive rock._

 

did you like Moon? its RMAA measurements are as lousy as can get, and it sounds like a cheap car stereo to me...Kingwa thinks mine was faulty 
	

	
	
		
		

		
			





 I'm completely stunned by the 2*LT1364+Earth, it's eye popping 
	

	
	
		
		

		
		
	


	




 I've ordered a whole bunch of Earth and Sun V2...can't wait to try them on the Claro Halo soundcard


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_did you like Moon? its RMAA measurements are as lousy as can get, and it sounds like a cheap car stereo to me...Kingwa thinks mine was faulty 
	

	
	
		
		

		
		
	


	




 I'm completely stunned by the 2*LT1364+Earth, it's eye popping 
	

	
	
		
		

		
		
	


	




 I've ordered a whole bunch of Earth and Sun V2...can't wait to try them on the Claro Halo soundcard 
	

	
	
		
		

		
		
	


	


_

 

Out of the three, I liked Moon the least. I would like to try them in some circuits other than the Compass which was mediocre at best. I might pick up a couple of single channel HDAMs and try them in my modded Lite Dac-AH.


----------



## ROBSCIX

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Anymore Sun V2 to Earth comparison? The Sun is too bright for me now, considering selling it if it stays this way._

 

I like the Sun V.2 also but prefer the Earth for I/V.


----------



## crapback

I'm thinking about swapping out the evox bypass caps for some k40y9 pio's to see if that changes the sound characteristics of the hdams. I like the dynamics of the sunv2, but it is too bright for my tastes, both in my zero and in my compass. I don't really like the moon in my compass, but in my zero it sounds pretty good in the dac. I'm trying that out for a while to give it a chance, cause I already know I love the earth in there.


----------



## ROBSCIX

A few said they like the discrete better without the caps.

 I find the Earth is really good for I/V but the Sun may give a signature that some may find bright..depend alot on the circuit and what your using for cans/speaker etc.


----------



## leeperry

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I already know I love the earth in there._

 

yeah, Earth is cool stuff! I've tried it w/ the OPA827 as final buffer...but I'm currently listening to 2*Earth alone w/o a final buffer, vocals are not in front like on the LT1364 anymore...it's more natural, the LT1364 was obviously pushing them upfront at the first row, they are seamlessly mixed within the SS now.





 it seems that the more Earth you stack, the better the SQ....can't wait to put 4 of them on the Claro Halo(w/ 5cm extension leads): http://www.bukowc.com/Galerija/Avtom...aroHaloXT6.JPG





*PS:* it's funny how loudness material was totally unbearable on IC's, but is now totally OK on the Earth...sound is still brickwalled to death but the SS is not one big clipped mess anymore, there's still some life


----------



## LuciferX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_
 it seems that the more Earth you stack, the better the SQ....can't wait to put 4 of them on the Claro Halo(w/ 5cm extension leads): http://www.bukowc.com/Galerija/Avtom...aroHaloXT6.JPG




_

 

Let me know your test results! You have buy it a Claro Halo? If you have some time, Can you test how different is the sound with 4 default opamps vs 4 x 2132 and 2 x default + 2 x 2132?


----------



## leeperry

yeah, a friend of mine wants a good multichannel soundcard...and he wants a whole bunch of discrete op-amps too, now that he's heard them on my HD2 
	

	
	
		
		

		
		
	


	




 well, I can already tell that it'll end up with 2*Earth and 2*LT1364..or possibly 4*LT1363 
	

	
	
		
		

		
		
	


	




 LT136x is the shznit for vocals(it makes movies "holographic") and Earth allows it to blossom...Earth w/o LT1364 is natural and boring, and LT1364 w/o Earth is not refined enough to my taste 
	

	
	
		
		

		
		
	


	




 whatever U8/U10 or U9/U11 still remains to be decided...

 BTW, can you run a few tests for me please? I've explained it here: http://www.head-fi.org/forums/f46/ht...1/index13.html

 and it's better that we discuss there, as this is the right thread


----------



## leeperry

BTW, replacing 2*LT1364+OPA2132P by 2*LT1364+1*Earth opened the SS in a pretty tremendous way...even wider than the OPA827, it just sounds miles better!

 but I've just tried 2*Earth+1*LT1364 and it's terrible 
	

	
	
		
		

		
		
	


	




 SS is narrow/bloated, all the Earth details have gone down the drain...only the killer vocals are back. I will replace it by 2*LT1363 and 2*LT1028 tommorow, but anyway yeah...dual op-amps are evil cross-talk wise


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I'm thinking about swapping out the evox bypass caps for some k40y9 pio's to see if that changes the sound characteristics of the hdams. I like the dynamics of the sunv2, but it is too bright for my tastes, both in my zero and in my compass. I don't really like the moon in my compass, but in my zero it sounds pretty good in the dac. I'm trying that out for a while to give it a chance, cause I already know I love the earth in there._

 

Have you tried any caps mods yet on these units or just considering it?
 I mentioned before that I heard a few guys say they prefer these units without the caps.


----------



## crapback

I haven't had a chance to try any yet. Maybe tomorrow night when I get back home, if I can get motivated. If not I'll try it tuesday. Being a truck driver makes this hobby a little difficult to keep up with sometimes.


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I haven't had a chance to try any yet. Maybe tomorrow night when I get back home, if I can get motivated. If not I'll try it tuesday. Being a truck driver makes this hobby a little difficult to keep up with sometimes. 
	

	
	
		
		

		
		
	


	


_

 

OK, I see. Post you results when you get time to test.
 I have considered trying new ones myself o possible trying the units without caps on them at all.


----------



## leeperry

BTW, I might try the LT1028ACN8 on these : Single-to-dual Op-AMP Adapter - DIP version (p/n 021001)

 and this: http://images17.newegg.com/is/image/...04-S01?$S640W$

 if the caps are too high, I will had an additional dip8 socket between the card and the adapter to rise it a bit....LT1363CS8 and LT1028ACN8 will be my last tries at IC's I think


----------



## ROBSCIX

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_You should use Ohm's law. R=U/I. A couple of mA is enough. Eg if the supply is +/- 10 V and you want 2 mA: R=10/0.002 => R=5k. I guess the recommended 2k2 or 3k3 is fine too.

 Consider using constant current sources instead, like a JFET with appropriate source resistor. Look at how it's done in PIMETA, PPA or M3. You don't need cascoded JFETs._

 

I have new adapters coming and a large selection of resitors, time to get into some new testing. Some I have spoke with about this topic said that experimenting with values may give the best results. I have been considering a constant current source for this application. As I said I am just getting into biasing to class A with opamps. Do you use any opamps that are biased?


----------



## diditmyself

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Do you use any opamps that are biased?_

 

I stopped class A biasing of opamps after I did some blind tests. All testing was with constant current sources. I couldn't hear any improvement. In fact I heard no difference at all. Before that I experimented with restistors, and at that time I thought I could hear the difference, and it was to the better. Now I think that it might have been placebo. Those tests were with the opamps in front of diamond buffers, a very light load, 100's of kOhm.

 I've tried 15 mA class A biasing of AD8397, driving high impedance phones, and I could hear no difference in blind tests.

 Maybe I didn't give it enough time. Flipping back and forth with a switch isn't the same as long time listening. All my discrete amps are class A. I think I'm sure that they sound less fatiguing in the long run at higher bias.


----------



## ROBSCIX

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_I stopped class A biasing of opamps after I did some blind tests. All testing was with constant current sources. I couldn't hear any improvement. In fact I heard no difference at all. Before that I experimented with restistors, and at that time I thought I could hear the difference, and it was to the better. Now I think that it might have been placebo. Those tests were with the opamps in front of diamond buffers, a very light load, 100's of kOhm.

 I've tried 15 mA class A biasing of AD8397, driving high impedance phones, and I could hear no difference in blind tests.

 Maybe I didn't give it enough time. Flipping back and forth with a switch isn't the same as long time listening. All my discrete amps are class A. I think I'm sure that they sound less fatiguing in the long run at higher bias._

 

I have to run tests for myself and gauge the results. Some suggest this mod as a good option and others not so much so I need to check for myself.
 The testing never ends around here...


----------



## crapback

Ok, I went for the bypass cap switch with some k40y9's. I've only done the earth in the dac so far cause with the pio's on there they take up a lot more space. I'll have to figure out how to fit them in the case. I'm not sure if the bass has actually improved or not but I'm going to keep them on there just for the fact that the hdams now look like tiny versions of shark diving cages. 
	

	
	
		
		

		
		
	


	




 I really need more free time if I'm going to get a chance to legitimately compare the hdams with and without bypass caps and with the different bypass caps. I guess I'll throw some more k40y9's on the amp hdams and see how she sounds.


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_Ok, I went for the bypass cap switch with some k40y9's. I've only done the earth in the dac so far cause with the pio's on there they take up a lot more space. I'll have to figure out how to fit them in the case. I'm not sure if the bass has actually improved or not but I'm going to keep them on there just for the fact that the hdams now look like tiny versions of shark diving cages. 
	

	
	
		
		

		
		
	


	




 I really need more free time if I'm going to get a chance to legitimately compare the hdams with and without bypass caps and with the different bypass caps. I guess I'll throw some more k40y9's on the amp hdams and see how she sounds._

 

Great stuff.
 Post you listening impression when you get a chance to have a listen.


----------



## crapback

I now have k40y9's on all 3 earth's. I really wish I had ordered some clear heatshrink that would've fit over the k40's. I shouldn't admit to liking the look of any capacitors but I think the k40's look sweet. Maybe it's just placebo effect but I swear I can hear a difference already. This is going to take a while and I think I'm going to enjoy every minute of it. 

 I included some more pictures of the modules crammed into the zero case. There's also a pic with the k40y9 and one of the stock evox caps so you can really see the difference in size. I also threw in a picture so you can see the el cheapo stepper I put in there with a solder job only a plumber could be proud of. 
	

	
	
		
		

		
		
	


	


DACT Type 21 Stepped Attenuator Potentiometer 100K 2A3 - eBay (item 120471954152 end time Sep-27-09 14:56:18 PDT)


----------



## murrays

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I now have k40y9's on all 3 earth's. I really wish I had ordered some clear heatshrink that would've fit over the k40's. I shouldn't admit to liking the look of any capacitors but I think the k40's look sweet. Maybe it's just placebo effect but I swear I can hear a difference already. This is going to take a while and I think I'm going to enjoy every minute of it. 

 I included some more pictures of the modules crammed into the zero case. There's also a pic with the k40y9 and one of the stock evox caps so you can really see the difference in size._

 

Are you picking up noise from that transformer? You may hear a buzz or humm when no music is playing? I say that because I am in the middle of shielding & re-positioning components to cure such noise in my amp - and my components are further away from the transformer. I see you have one capacitor resting right against it. I am finding that just moving some of the larger capacitors around is helping to eliminate most of it. You may be lucky with a better quality transformer (or just lucky...).

 With bypassing caps you want to keep the leads as short as possible. Long leads (and large size) can impede the HF characteristics.


----------



## crapback

I guess I'm just lucky then. There is a very slightly audible hiss when I turn the volume to maximum with no music playing but no buzzing or humming. That's what I was worried about when I first put the hdams in my zero. I bring it with me during the week in my truck at work so I need to be able to keep it closed up. That doesn't leave me any better options for now until I find a better job that'll let me actually live in an apartment again. 
	

	
	
		
		

		
		
	


	




 As for short leads, I can't really make them much shorter and still solder them onto the hdams. I could trim off about 7-8mm off each, but I don't really think that would make any real audible difference. There really is no lack of high frequency extension of detail with my zero now. 22 k40y9 bypass caps in total and a cheap stepper have made huge improvements in my little monster. That and add about 2 pounds to the weight of the thing. 
	

	
	
		
		

		
		
	


	




 When it becomes a stationary zero I'll work on repositioning the hdams for a cleaner install. For now, I can live with any noise generated by the proximity of the components cause I can't hear it having any effect on my music at the volumes I listen at. 

 I also wanted to add that it might be the rather heavy metal casing of the k40's that is providing some decent shielding in my situation. Or I guess it could just be luck.


----------



## leeperry

damn, it's a major pain to reuse browndogs...I've had one of the browdog tracks dying on me, so I had to desolder the 2*LT1363 to put them back on another one...even w/ desoldering braid it was a major PITA to take them off in one piece 
	

	
	
		
		

		
		
	


	




 I really don't see how you can reuse these things..

 and going LT1364>2*LT1363 improves the stereo separation pretty drastically! but I still feel that these cheapo browndogs are poorly shielded to EMI...so DIP8 is definitely better if the chip does the +/- polarities of the same channel...but a dual chip for stereo is indeed worthless.


----------



## ROBSCIX

Why would you reuse them? Your going to ruin the adapter and the opamp.
 Just buy new ones.


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I guess I'm just lucky then. There is a very slightly audible hiss when I turn the volume to maximum with no music playing but no buzzing or humming. That's what I was worried about when I first put the hdams in my zero. I bring it with me during the week in my truck at work so I need to be able to keep it closed up. That doesn't leave me any better options for now until I find a better job that'll let me actually live in an apartment again. 
	

	
	
		
		

		
		
	


	




 As for short leads, I can't really make them much shorter and still solder them onto the hdams. I could trim off about 7-8mm off each, but I don't really think that would make any real audible difference. There really is no lack of high frequency extension of detail with my zero now. 22 k40y9 bypass caps in total and a cheap stepper have made huge improvements in my little monster. That and add about 2 pounds to the weight of the thing. 
	

	
	
		
		

		
		
	


	




 When it becomes a stationary zero I'll work on repositioning the hdams for a cleaner install. For now, I can live with any noise generated by the proximity of the components cause I can't hear it having any effect on my music at the volumes I listen at. 

 I also wanted to add that it might be the rather heavy metal casing of the k40's that is providing some decent shielding in my situation. Or I guess it could just be luck. 
	

	
	
		
		

		
		
	


	


_

 

You could always add some sheilding, if you find it is a issue.


----------



## crapback

I don't think I need to shield anything just yet, there isn't enough noise to affect my enjoyment of the music. Now I'm intrigued by the audio changes,(if in fact they are real), of the new bypass caps on my hdams. I'm back to playing with my compass again to check things out. Looks like I'm back to rolling opamps again, even if they are discreet. 
	

	
	
		
		

		
		
	


	



 If head-fi itself is an addiction, what drug would opamp rolling be?


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I don't think I need to shield anything just yet, there isn't enough noise to affect my enjoyment of the music. Now I'm intrigued by the audio changes,(if in fact they are real), of the new bypass caps on my hdams. I'm back to playing with my compass again to check things out. Looks like I'm back to rolling opamps again, even if they are discreet. 
	

	
	
		
		

		
		
	


	



 If head-fi itself is an addiction, what drug would opamp rolling be?_

 

It was just a suggestions if the noise bothered you. So your hearing differences? 
 They are positive or you haven't had time to compare yet?


----------



## crapback

I didn't mean to come off snotty in any way. I forget sometimes how I need to add more smilies to convey my tone of voice. 
	

	
	
		
		

		
		
	


	




 I would have put the emphasis on the "just yet" to say that I haven't screwed the pooch so far. 
	

	
	
		
		

		
		
	


	




 I swear I hear better detail with my compass now both in the high and low range. There was a lot of the resonance of cymbals missing before that I'm noticing now. Bass guitars also sound better like the tone of Geddy Lee's Rickenbacker. Or I might just be looking for more detail now that I've changed something in my setup. I don't know for sure. I don't really feel like swapping bypass caps over and over to compare them properly. I like how they sound and if the k40y9's give me a placebo effect I'll take it. 
	

	
	
		
		

		
		
	


	




 I should have more than enough hours on both the compass and the earth in it to pass any burn-in standards for audio-gd gear so that shouldn't be part of it. I'm still keeping an open mind on the whole electronics burn-in issue.


----------



## ROBSCIX

Oh no, I didn't think you were being "snotty". Post your results when you have more time to compare.


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_... but I still feel that these cheapo browndogs are poorly shielded to EMI._

 

I was thinking of ordering some of these - can you explain what is the problem with them? I wasn't aware they had any shielding.


----------



## diditmyself

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_I was thinking of ordering some of these - can you explain what is the problem with them? I wasn't aware they had any shielding._

 

I've never seen an adapter with shield. Opamps don't have ground pins. I guess you could connect a shield to one of the rails. Is this how it's done in the metal can opamps?

 I've just ordered some of those cheap SOIC to DIP adapters from Hong Kong. The traces are _much_ shorter and look sturdier than Browndogs.

 If usual care is taken with decoupling caps as close to the power pins as possible, short feedback path, an input resistor and maybe an input filtering cap, I think you'll be fine. The use of an output resistor and/or a zobel network make the amp more stable driving capacitive loads. The use of a compensation cap when needed, or choosing "the right" value for feedback resistors also increase stability.


----------



## murrays

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_I've never seen an adapter with shield. Opamps don't have ground pins. I guess you could connect a shield to one of the rails. Is this how it's done in the metal can opamps?

 I've just ordered some of those cheap SOIC to DIP adapters from Hong Kong. The traces are much shorter and look sturdier than Browndogs.

 If usual care is taken with decoupling caps as close to the power pins as possible, short feedback path, an input resistor and maybe an input filtering cap, I think you'll be fine. The use of an output resistor and/or a zobel network make the amp more stable driving capacitive loads. The use of a compensation cap when needed, or choosing "the right" value for feedback resistors also increase stability._

 

Yes, thanks. I have been working through a lot of those issues over the past few months with my amp. Bypass caps are soldered on the underside of the PCB, directly to the pins. Choosing the right input resistors definitely helped. Pretty much everything you mention has been done - and a few more. It helps having an old oscilloscope to hand to see if there's oscillations. 

 It goes against logic to get "a bad feeling" about the lack of shielding on the Browndogs when each extension cable to those discrete modules uses nearly a metre of wire.


----------



## 12Bass

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_I've just ordered some of those cheap SOIC to DIP adapters from Hong Kong. The traces are much shorter and look sturdier than Browndogs._

 

Like this?

4 set SOIC to DIP 8-pin Convert PCB Adapter SMD OPA627 - eBay (item 230378690602 end time Nov-15-09 22:14:22 PST)


----------



## leeperry

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_It goes against logic to get "a bad feeling" about the lack of shielding on the Browndogs when each extension cable to those discrete modules uses nearly a metre of wire._

 

maybe because the HDAM are grounded and use caps to minimize oscillation? and maybe because the Earth also sounds amazing? besides I've ordered twice shorter leads, so I'm working on it ^^

 pretty much each time I've tried browndog's, the sound has had distorted trebles to death. like OPA2132P that was sounding great, and OPA132U that was distorted and whiney 
	

	
	
		
		

		
			





 anyway, the last two IC op-amps I wanna try are LT1028 and LT1353...but having second thoughts, I will give up on those adapters...I'll use the DIP8 versions and try to find sturdier adapters than browndog's. DIP8 is good to fight EMI.

 besides, the highest LT1028 grade is only available in DIP8.


----------



## leeperry

indeed these adapters look nice! I saw them on some asian site, but couldn't locate them for sale.

 more explanations about their shielding: 10pcs Dual SOIC to DIP-8 Convert PCB Adapter SMD OPA627 - eBay

 maybe the browdogs just suffer from poor design, after all


----------



## igor0203

Did somebody tried LT1816 or LT1819?


----------



## ROBSCIX

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_Did somebody tried LT1816 or LT1819?_

 

Hmm, I don't remember any post in this thread about those units. Could be wrong did you do a search? LT doesn't really concentrate on the audio market and most of their opamps are meant for others tasks. You can get some that sound quite good but with others it is a bit of a crap shoot.


----------



## igor0203

I ordered each one from Farnell but was interested if somebody tested them. First I'll have to get few more SOIC to DIP8 adapter so I can test them.


----------



## ROBSCIX

Well post your impressions when you test them.


----------



## igor0203

Yes, sir!


----------



## leeperry

I didn't hear much difference while Earth was burning in, but I'll let Sun V2 burn in:



 

 

 it's less tubey than Earth, but the bass is a bit shy to my taste 
	

	
	
		
		

		
		
	


	




 I love the crazy low end bass on the Earth 
	

	
	
		
		

		
		
	


	




 humm, the magic is gone I think...I'll put back the Earth later today, and I'm buying a burson from a friend...that should give 
	

	
	
		
		

		
		
	


	




*PS1:* ah well...less tubey but less colored, I think 2*Sun>1*Earth will be neato.

 I'm rearranging my box, I'll try to get rid of the extensions by using additional gold plated sockets as risers.

*PS2:* ahhhhhhh the alternative takes on the 24/96 DVD-A of "In the Court of The Crimson King" really sound amazing right now...if only that doofus would stop playing flute in my room right next to me 
	

	
	
		
		

		
		
	


	




 and BTW, anyone knows where to buy some AD797BN 
	

	
	
		
		

		
		
	


	




 apparently the whole AD797B line has been phased out :/


----------



## SpudHarris

I'm told that the ada4627-1 is the next big thing...... Anyone tried them? I can't get them here in the UK, do AD offer samples


----------



## leeperry

well, LT1364 gives a magic touch to vocals but it basically mono-izes them to death..2*LT1363 on adapters was a far cry as far as stereo separation was concerned.

 2*Sun>1*Earth is true dual mono from A to Z, amazing!







 and putting additional sockets as risers is just not manageable:


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I'm told that the ada4627-1 is the next big thing...... Anyone tried them? I can't get them here in the UK, do AD offer samples 
	

	
	
		
		

		
		
	


	


_

 

I haven't tried them yet but I think I heard these mentioned by others. I will have to get some and try them out. Thx for the heads up.


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I'm told that the ada4627-1 is the next big thing...... Anyone tried them? I can't get them here in the UK, do AD offer samples 
	

	
	
		
		

		
		
	


	


_

 

 Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I haven't tried them yet but I think I heard these mentioned by others. I will have to get some and try them out. Thx for the heads up._

 

I ordered a couple. They are not cheap!


----------



## SpudHarris

Where did you get them Doug? any chance of getting me a couple? I can get them through Farnell but it's US stock with like a $30 surcharge :^(


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Where did you get them Doug? any chance of getting me a couple? I can get them through Farnell but it's US stock with like a $30 surcharge :^(_

 

Hey Nigel. I bought them directly from AD. I ordered 2 of the ARZ version as the BRZ is more expensive. If I like the ARZ, I will pick up the BRZ later.


----------



## leeperry

wow, Sun V2 is really amazing...it's just very clear and clean, perfect synergy on the AK4396 output w/ Earth as final buffer 
	

	
	
		
		

		
			





 can't wait to try replacing the Earth by a new burson...anyway, discrete is the way 
	

	
	
		
		

		
		
	


	




 it does a much more natural post-DAC filtering than the LT1364...which sounds bright/distorted and mono in comparison(yes I've switched a bunch of times).

 I've installed the wires in a neater way too:


----------



## SpudHarris

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Hey Nigel. I bought them directly from AD. I ordered 2 of the ARZ version as the BRZ is more expensive. If I like the ARZ, I will pick up the BRZ later._

 

Thanks Doug. Doh! who'd have thought of ordering direct from the manufacturer 
	

	
	
		
		

		
		
	


	




. Got a couple of the ARZ's on order also.


----------



## Wfolio

I'm getting a burson coming Monday, have not tested discrete before, can't wait

 At this moment OPA128SM is the best OPAMP i have heard.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I ordered a couple. They are not cheap!_

 

I have a few BRZ's on the way for testing also. Enough to try testing on a few different circuits.


----------



## dex85

hi all, 

 i'm looking for some dual DIP-8 op-amps for I/V purpose. i usually prefer fluid, fast and transparent sound but i don't mind trying something different. thanks for the tips


----------



## SpudHarris

Quote:


  Originally Posted by *Wfolio* /img/forum/go_quote.gif 
_At this moment OPA128SM is the best OPAMP i have heard._

 

I should imagine they are something special @ £97 ($150) each 
	

	
	
		
		

		
		
	


	




 Wouldn't mind a listen though at some point.


----------



## Reima

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I should imagine they are something special @ £97 ($150) each 
	

	
	
		
		

		
		
	


	




 Wouldn't mind a listen though at some point._

 

They are only$71.97 at Digikey
	

	
	
		
		

		
		
	


	




.
 RC


----------



## 12Bass

Got around to doing a bit more testing, this time in the preamp section of my modded NAD 3150 integrated amplifier, monitoring with K702s through the headphone output. This time around I listened to OPA211, OPA2211A, OPA827, OPA1611, OPA1612, LME49720, LME49860, LM4562, XR5532, AD797, THS4052, OPA2107, and AD8599.

 The differences were generally audible, though less so among related parts like OPA211 and OPA1611. 

 Overall, I think I prefer the OPA827 in this application. It has more "life" to it, good separation, and there's something about the midrange which makes it sound a little more present, yet musical, IMO. Clear and punchy, but not harsh. 

 OPA211 - close to OPA827, yet not quite as euphonic. 2nd choice overall. Not sure which is more accurate. OPA1611 sounds similar, but maybe not quite as good? Would have to listen more to be sure. Pretty sure it wasn't better. Both of the dual parts (OPA2211A/OPA1612) sound smaller, less alive, and have less channel separation than the singles.... which sucks, because it costs more and is more of a hassle to use single op amps.

 The AD797 may be less colored, and sounds quite clean, but tends to be a bit boring somehow... and certainly not fatiguing.

 THS4052 - probably a bit more open than all of the others... not offensive, just sort of lacking much character. Neutral/transparent? Sucks up current.

 The LM/LME family all sound similar. Heard more differences when comparing to unrelated parts than within this family. Perhaps a bit sterile, yet fairly detailed, but not among the best, IMO.

 OPA2107 - sounds "fine"... not outstanding... sort of "round" and a bit lacking in detail and life compared with the OPA827, which I would definitely recommend over the former if you need FET input. 

 XR5532 - reminded my why I changed the op amp in the first place. A bit "low fi"... not bad for 80s equipment, I guess....

 AD8599 - keep wanting this chip to do something for me, however it also seems to be bettered by others. Sort of round/warm sounding, not a whole lot of detail. Didn't stay in long.... 

 OPA827s on BrownDog:


----------



## diditmyself

Nice review 12bass. Can't wait 'til I get new SOIC to DIP adapters to try OPA827. All the LME chips _are_ the same so it's no wonder they do sound the same. I think OPA1611 and OPA2211 are the same parts under different names wich supports your listening impressions.

 I think that JFET input amps have a certain sound compared to bipolar imput amps. JFETs are more euphonic but can be a little grainy. Better JFET amps with cascoded input stage like OPA627 has less grain (so I hope it's the same with OPA827).

 Can anyone understand why they still put NE5532s in HiFi amps, DACs and DCPs? It's only a couple of bucks to save from using better parts like LME49720! They spend more money on BS knobs, switches, cables and boxes with no sound improvement at all.


----------



## ROBSCIX

Quote:


  Originally Posted by *Wfolio* /img/forum/go_quote.gif 
_I'm getting a burson coming Monday, have not tested discrete before, can't wait

 At this moment OPA128SM is the best OPAMP i have heard._

 

There are a few other metal can opamps from that company but they are not meant for audio work. That is not to say they won't sound good.
 Have you heard the 627,637SM?
 The OPA111SM -IIRC, is also a great opamp.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Got around to doing a bit more testing, this time in the preamp section of my modded NAD 3150 integrated amplifier, monitoring with K702s through the headphone output. This time around I listened to OPA211, OPA2211A, OPA827, OPA1611, OPA1612, LME49720, LME49860, LM4562, XR5532, AD797, THS4052, OPA2107, and AD8599.

 The differences were generally audible, though less so among related parts like OPA211 and OPA1611. 

 Overall, I think I prefer the OPA827 in this application. It has more "life" to it, good separation, and there's something about the midrange which makes it sound a little more present, yet musical, IMO. Clear and punchy, but not harsh. 

 OPA211 - close to OPA827, yet not quite as euphonic. 2nd choice overall. Not sure which is more accurate. OPA1611 sounds similar, but maybe not quite as good? Would have to listen more to be sure. Pretty sure it wasn't better. Both of the dual parts (OPA2211A/OPA1612) sound smaller, less alive, and have less channel separation than the singles.... which sucks, because it costs more and is more of a hassle to use single op amps._

 

I have found the same thing with single channel units Vs. Dual channels. If I am budiling new units I try to build a dual single channel unit and a single dual channel unit for testing. I have been getting great results with the dual 1611 modules I have built.


----------



## leeperry

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_Can anyone understand why they still put NE5532s in HiFi amps, DACs and DCPs? It's only a couple of bucks to save from using better parts like LME49720!_

 

essentially because it's the industry standard...many ppl think it's the best op-amp on the market, because most records you'll be listening to literally went through hundreds of 5534/5532.

 I also know some sound engineers who find it to be the best op-amp, and I would definitely prefer a 5532 over a 49720 anyday 
	

	
	
		
		

		
		
	


	




 but I like NJM4580, it's fantastic to drive headphones...it's not because a chip has a low price that it must be dismissed, provided that the surrounding circuit has a cooperative layout.


----------



## ROBSCIX

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_
 Can anyone understand why they still put NE5532s in HiFi amps, DACs and DCPs? It's only a couple of bucks to save from using better parts like LME49720! They spend more money on BS knobs, switches, cables and boxes with no sound improvement at all._

 

Sure, it is a generic audio opamp. Many designers consider it perfectly suitable for audio work providing the circuit is designed properly.
 There are some that enjoy the sound of the 5532 also, being that it isn't overly clean or sterile sounding.


----------



## Pluto2

Thank you so much for the nice review on those opamps 12bass!! Helpful for my selection : )


----------



## leeperry

Quote:


  Originally Posted by *Wfolio* /img/forum/go_quote.gif 
_I'm getting a burson coming Monday_

 

yep, I'm also expecting a new burson...Slash47 told me it'd sound slightly better than Earth, evil upgraditis


----------



## ROBSCIX

Quote:


  Originally Posted by *Wfolio* /img/forum/go_quote.gif 
_I'm getting a burson coming Monday, have not tested discrete before, can't wait

 At this moment OPA128SM is the best OPAMP i have heard._

 

IIRC, the OPA128SM is a single channel TO-99 opamp. Are you using in a signle channel configuration or dual using an adapter?
 I actually have this unit on a list of new TO-99 I would like to build.
 Have you heard any others SM versions?


----------



## 12Bass

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Thank you so much for the nice review on those opamps 12bass!! Helpful for my selection : )_

 

Good if taken with a grain of salt, I suppose.... my subjective perceptions based on this particular application. 
	

	
	
		
		

		
		
	


	




 FWIW, I'd suggest AD8397 over NJM4580 for driving headphones. Found the 4580 somewhat harsh and murky, while the AD part is clearer/cleaner and has several times the output current drive.

 Maybe I'll try discretes one of these days....


----------



## diditmyself

I also find NE553x OK, but never more than OK. It's never great. OK isn't OK with me. In a boom box or guitar amp they're probably more than enough, but not in a HiFi amp. I don't think LME49720 is the best there is either, but it's far better than NE553x. Both of these chips are dull. Somewhat neutral but dull. I've never used NE553x more than just to know how it sounds. The LME49xxx (LM4562) chips have been OK for a couple of days, but then I've turned to something else, something more exciting. I'm a neutrality freak, but if I have to choose from neutral but slightly dull or neutral but slightly colorful, it's an easy choice.


----------



## stringgz301

Question: how do you calculate the resistor value to bias an opamp to class A? 
	

	
	
		
		

		
		
	


	




 I'm trying to do this to a opa350 but don't know how to calculate it.

 Thanks in advance.


----------



## diditmyself

Quote:


  Originally Posted by *stringgz301* /img/forum/go_quote.gif 
_Question: how do you calculate the resistor value to bias an opamp to class A? 
	

	
	
		
		

		
		
	


	




 I'm trying to do this to a opa350 but don't know how to calculate it.

 Thanks in advance._

 

Post #1475 in this thread
http://www.head-fi.org/forums/f6/opa...ml#post6122504


----------



## Wfolio

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_IIRC, the OPA128SM is a single channel TO-99 opamp. Are you using in a signle channel configuration or dual using an adapter?
 I actually have this unit on a list of new TO-99 I would like to build.
 Have you heard any others SM versions?_

 


 tried OPA128SM & OPA627SM. all bought from Farnell. OPA637SM is out of stock. only managed to get OPA637BM 

 using browndog to run them in pair. added short extension cable in I/V due to sockets spacing.

 currently configuration is OPA128SMx4(I/V), OPA627SMx2(buffer) and OPA627SMx2(pre-out section of my dac).


 the production status of OPM128SM, 627SM & 637SM have all become NRND. have some concern that TI may stop producing them in near future.

 The SM series is indeed special.

*OPA627SM* - laid back 

*OPA637BM* - more imposing than 627 
_(I believe SM version is better than BM judging from the sound quality of OPA627SM)_

*OPA128SM* - have quality of OPA627SM (maybe not as quiet) but the characteristic is totally different! It's more passionate and lively.


----------



## Wfolio

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_yep, I'm also expecting a new burson...Slash47 told me it'd sound slightly better than Earth, evil upgraditis 
	

	
	
		
		

		
		
	


	


_

 

Was told the leads of burson can't fit into dip8 socket, I'm worrying about this... intend to get it first then try figure out the workaround later

 keep us posted on how's burson vs opa-earth/sun..thks


----------



## ROBSCIX

Quote:


  Originally Posted by *Wfolio* /img/forum/go_quote.gif 
_tried OPA128SM & OPA627SM. all bought from Farnell. OPA637SM is out of stock. only managed to get OPA637BM 

 using browndog to run them in pair. added short extension cable in I/V due to sockets spacing.

 currently configuration is OPA128SMx4(I/V), OPA627SMx2(buffer) and OPA627SMx2(pre-out section of my dac).


 the production status of OPM128SM, 627SM & 637SM have all become NRND. have some concern that TI may stop producing them in near future.

 The SM series is indeed special.

*OPA627SM* - laid back 

*OPA637BM* - more imposing than 627 
(I believe SM version is better than BM judging from the sound quality of OPA627SM)

*OPA128SM* - have quality of OPA627SM (maybe not as quiet) but the characteristic is totally different! It's more passionate and lively._

 

Using brown dogs? are you using two single TO-99 adapters with single channel to dual adapters?
 I am just asking because I have never seen the proper dual TO-99 adapter made from Brown dog. You can use a few to make one though.
 I have 627 and 637SM and they are some of my favorites, but I have other SM version on my every growing list of units to build. Seems I am building new opamps modules every week or people are sending me units to test.


----------



## 12Bass

Just tried LME49722MA against LME49720, OPA1612, and OPA827 x 2. Still prefer the OPA827 - sounds more alive with better separation. In particular I was curious to compare LME49720NA with LME49722MA (on DIP socket). The LME49722MA is similar, like the LM4562/LME49860, but seems to have a bit more bottom end authority compared to its siblings. Maybe a bit more lively as well, as in not as sterile. It also draws more current. Still not as good as the recent TI OPA chips, IMO....


----------



## 12Bass

Finally mounted 2 x ADA4898-1 on a BrownDog adapter. From a quick audition, this part sounds a bit more "in your face" than the OPA827/OPA211 family. Perhaps not as dynamic? A little less detail and spacial information compared to the TI parts. Not bad sounding, though. Draws a lot of current (16 mA) and gets quite warm to the touch. Not sure, but could be unstable in this circuit, even though there is PSU bypassing and 10 pF in the feedback loops for each channel. For bipolar input, I prefer OPA211/1611.


----------



## 12Bass

BTW, judging from my experience with THS4052, I suppose that 2 x THS4051 might be a good choice for those looking for something open/transparent sounding, perhaps for I/V stages. Need to be mindful of the circuit to keep it stable, however, and also the current draw. Also note that these parts can generate more DC offset than most of the LM/LME/OPA211/827/ADA4898-1 type parts.


----------



## 12Bass

And finally, listened to 2 x OPA132UA compared with OPA2132P and 2 x OPA827. Perhaps not surprisingly, I found the OPA132 to have a similar warm, somewhat veiled, smooth tonality like its dual sibling, though perhaps a bit more life and separation with the two singles. The OPA132 might be a little more open sounding than the OPA2132 dual, but still pales compared to OPA827, IMO, which is more vibrant and resolving overall. That's not to say the OPA827 is categorically "the best"... just that it sounds the best to me in this particular circuit (NAD 3150).


----------



## SpudHarris

Well I've kept the OPA827 in my P3+ Headphone Amp since I first tested them which is about 3 weeks. I have gone back to my favourites periodically to see if I prefer them (AD797/OPA132AU) but no, rolling is halted by these chips which just tick all the boxes for me.


----------



## Pluto2

How close is OPA827 compared to it's second place, OPA211 would you say 12bass?


----------



## K3cT

I want to order some AD843 from Farnell for experiments. Which versions should I go with, the AD843JNZ or AD843KNZ? Also, their descriptions say that they come in PDIP8 package, that's the same with normal DIP8 yes?

 Thanks in advance for the help, guys.


----------



## ROBSCIX

Yes PDIP = Dip8. Also verify that is has the right amount of channel you need as DIP opamp can come in 1 or 2 channel versions. Usually coding after the product number varies from company to company but many times it has to do with environmental concerns such as no lead...etc. The coding legend should be in the products spec sheet.


----------



## ROBSCIX

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_How close is OPA827 compared to it's second place, OPA211 would you say 12bass?_

 

I have tested both of these units...If I had to choose one though I would go for the 827.


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I have tested both of these units...If I had to choose one though I would go for the 827._

 

I've also tested both and although our applications vary the 827 comes out on top with me also, it sure is a nice Opamp.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I've also tested both and although our applications vary the 827 comes out on top with me also, it sure is a nice Opamp._

 

Yes, People there that have actually tested the unit all have positive impression of it. According to the posts in this thread.


----------



## 12Bass

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_How close is OPA827 compared to it's second place, OPA211 would you say 12bass?_

 

Hmmm..... My experience is that they are more similar than different, when compared with other chips. A lot will depend on the circuit, and personal taste. If you're replacing a FET device in a high impedance circuit, then the OPA827 is the obvious choice. I tried the OPA211 in a high impedance section and it sounded weak and somewhat noisy. However, in the proper circuit, it sounds very good, IMO. Overall, I've found that the OPA827 can have a little something extra that some may or may not like.... sort of a euphonic presence in the midrange area, while the OPA211 might be a bit less colored. Bear in mind that I've done no proper testing to confirm any of this... just based upon subjective listening.


----------



## leeperry

LT1361 is nice too 
	

	
	
		
		

		
			





 it's like a LT1364 with less 2nd/3rd order THD, it leaves more room to the Earth to express itself...so far so good


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Hmmm..... My experience is that they are more similar than different, when compared with other chips. A lot will depend on the circuit, and personal taste. If you're replacing a FET device in a high impedance circuit, then the OPA827 is the obvious choice. I tried the OPA211 in a high impedance section and it sounded weak and somewhat noisy. However, in the proper circuit, it sounds very good, IMO. Overall, I've found that the OPA827 can have a little something extra that some may or may not like.... sort of a euphonic presence in the midrange area, while the OPA211 might be a bit less colored. Bear in mind that I've done no proper testing to confirm any of this... just based upon subjective listening._

 

Personally, I find the OP827 makes a very good I/V opamp. I have tested the 211 for buffer but in a different circuit.
 IIRC, both opamps were released around the same time.

 Have you had a chance to test the 161X series?


----------



## 12Bass

Made mention of the OPA1611 here: http://www.head-fi.org/forums/f6/opa...ml#post6140712

 Haven't done any exhaustive comparisons, though from a limited audition, it sounds very much like the OPA211.... which should be no surprise.


----------



## leeperry

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_it sounds very much like the OPA211.... which should be no surprise._

 

a while ago, you said that there was no in-house sound for each brand...well today I've rolled from 1364>1361>1213acn8, they still carry a lot of similarities. identifying 1361 and 1213 in a DBT would be pretty hard, 1364 is more distorted and very colored so this one would be easy.

 1213 was nice but too clean before, but w/ the Earth as final buffer it's nicer by the hour! SS is wider than the 136x serie.

 I wonder if 1211/1213/1215 would sound any different...basically it's the same chip w/ 3 different kinds of specs?!

 and Earth makes sure that you get some killer bass, good chip


----------



## 12Bass

Well, from all appearances, OPA1611/12 are (practically) the same chips as OPA211/2211A, but with relaxed DC specifications, so it isn't exactly surprising that they sound similar. They're not like OPA2604/2132/34, however, so I can't say that they confirm the notion of a TI/BB "house sound". One of the problems is that people tend to base such conclusions on a limited sampling.


----------



## leeperry

hummm I thought going discrete would stop this rolling frenzy...but I'm now looking for the best ones to feed the Earth 
	

	
	
		
		

		
		
	


	




 Earth brings fantastic bass, balanced mids/trebles and very clear SS...all the layers are nicely laid off like cards on a table, so get some good cards in the first place...and you're in!

 LT1213 is great stuff...definitely a LM4562/49720 killer, it does everything the same...just better in every aspect. _"you may not be able to fight like a samurai, but you can at least die like a samurai"_





 the 24bit TrueHD track of "Up" sounds amazing on the 1213+Earth combo...such a wide and clear SS


----------



## Wfolio

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Using brown dogs? are you using two single TO-99 adapters with single channel to dual adapters?
 I am just asking because I have never seen the proper dual TO-99 adapter made from Brown dog. You can use a few to make one though.
 I have 627 and 637SM and they are some of my favorites, but I have other SM version on my every growing list of units to build. Seems I am building new opamps modules every week or people are sending me units to test._

 

I don't have a proper dual TO-99 adapter now. But I can find below two Asia suppliers

 diyrealaudio, have not buy anything from them yet, can accept paypal

 taobao is the largest 'eBay' in China, has all sorts of things including many DAC at unbelievable prices. Payment could be a problem for foreigner. I had once asked a China colleague to order a toy for me (deliver to Malaysia).






 about US$1/pc
diyrealaudio


 about US$0.5/pc
taobao


----------



## ROBSCIX

Quote:


  Originally Posted by *Wfolio* /img/forum/go_quote.gif 
_I don't have a proper dual TO-99 adapter now. But I can find below two Asia suppliers

 diyrealaudio, have not buy anything from them yet, can accept paypal

 taobao is the largest 'eBay' in China, has all sorts of things including many DAC at unbelievable prices. Payment could be a problem for foreigner. I had once asked a China colleague to order a toy for me (deliver to Malaysia)._

 

Sure, they are out there. I was just wondeirng if you were using the setup I mentioned. Using the single TO-99 adapters conencted to a dual DIP8 to single Dip8. Just curious. Whatever works!


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Well, from all appearances, OPA1611/12 are (practically) the same chips as OPA211/2211A, but with relaxed DC specifications, so it isn't exactly surprising that they sound similar. They're not like OPA2604/2132/34, however, so I can't say that they confirm the notion of a TI/BB "house sound". One of the problems is that people tend to base such conclusions on a limited sampling._

 

I have tested all in the above statment and personally, I wouldn't say the 161X or the 211 series has that typical Burr Brown soudn that others seem to exhibit. That may also be based on my limited testing though...


----------



## ecclesand

Does anyone know where to find resistor sockets? I've seen them before in pics but can't find where to buy them.


----------



## SpudHarris

Are you using them so you can bread board for testing various types? I've done that to test various caps and resistor before but I always break the pins out of DIP sockets for this purpose. 1 x DIP socket = 8 pins for about £0.50


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Are you using them so you can bread board for testing various types? I've done that to test various caps and resistor before but I always break the pins out of DIP sockets for this purpose. 1 x DIP socket = 8 pins for about £0.50 _

 

Actually, I want to roll different resistors in my DAC. I know...I must be out of my freaking mind! It's such a pain to take my Lite DAC-AH apart (the case has like 100 screws) and desolder and solder different resistors. I'm currently running it with some RIKENs I bought from Canada and I've got some other audio grade resistors on the way.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Does anyone know where to find resistor sockets? I've seen them before in pics but can't find where to buy them._

 

You could always solder in single pin header in each through hole. This way you could just insert whatever resistor you want. There may be other ways to go but this is one way.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_You could always solder in single pin header in each through hole. This way you could just insert whatever resistor you want. There may be other ways to go but this is one way._

 

Good idea! I was thinking of cutting a DIP8 socket in half and removing the middle pins but your idea sounds better. Thanks!


----------



## ROBSCIX

Yes, should work great. I was thinking about a similar system for caps in certain circuit location.
 Post some pics if you have time.


----------



## leeperry

Quote:


  Originally Posted by *Wfolio* /img/forum/go_quote.gif 
_diyrealaudio, have not buy anything from them yet, can accept paypal_

 

nice! he can ship two of these for USD12: Single-to-dual Op-Amp Adapter(include PIN 1u+ic socket 8pin 30u)

 too bad I already ordered browdogs...but these might be higher quality


----------



## Kuze

Quote:


  Originally Posted by *Wfolio* /img/forum/go_quote.gif 
_I don't have a proper dual TO-99 adapter now. But I can find below two Asia suppliers

 diyrealaudio, have not buy anything from them yet, can accept paypal

 taobao is the largest 'eBay' in China, has all sorts of things including many DAC at unbelievable prices. Payment could be a problem for foreigner. I had once asked a China colleague to order a toy for me (deliver to Malaysia).






 about US$1/pc
diyrealaudio


 about US$0.5/pc
taobao_

 

Tried ordering some parts from diyrealaudio, backed out cause i find it a bit lame they can't accept paypal, haven't heard anything bad about them and I've seen a few people here on the forum ordered parts from them, its still a hassle to go mail money order though.


----------



## Reima

Quote:


  Originally Posted by *Kuze* /img/forum/go_quote.gif 
_Tried ordering some parts from diyrealaudio, backed out cause i find it a bit lame they can't accept paypal, haven't heard anything bad about them and I've seen a few people here on the forum ordered parts from them, its still a hassle to go mail money order though._

 

They do take Paypal, you have to submit the order then Ben will send you an email showing the total you have to pay.
 RC

osCommerce


----------



## leeperry

yup, wait for Ben's email..took a half day to receive it.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Good idea! I was thinking of cutting a DIP8 socket in half and removing the middle pins but your idea sounds better. Thanks!
	

	
	
		
		

		
		
	


	


_

 

Since these guys posted a link to this place, what about these?
 They are single pins from sockets. -LINK

 They might work great!


----------



## Wfolio

anyone try those hard to find rare metal can from Linear Technology or Analog Devices?

 e.g.
 OP27AJ, Analog Devices
 LT1007XH, Linear Technology


----------



## qusp

hi guys, thought I would share this find with you; dont know if any of you have come accross these before and simply found them too pricey or what, but hereis where I bought some amazing little adapters of extremely high quality with several ready spots for adding resistors and caps, you'll probably need to put it through google translate from swedish. or try this link for the site put through google translate. I havent received mine yet; only ordered a coupe of days ago after finding a link from the Sjostrom audio  which has some wicked stuff ranging from the amazing SSB01 discrete level unity gain buffer thats inspired by the diamond buffer, which i'm building right now. Its a great little PCB that you guys might be able to use (no association) in your soundcards, no room in a portable amp or dac really. but yeah the adapters include single SOIC8->DIP8, DUAL SOIC8->DUAL DIP8, 2 x single SOIC8->Dual DIP8 and SOIC16->DIP8 (awesome). they all have pads for caps and resistors, as well as holes so you can pull a ground reference from below. checkem out. just thought they might work for some of you who have found the combination you are pretty happy with and would like to mount it properly. A bit expensive for breadboarding or experimentation, but the PCB and traces are substantial, so could probably take a fair few iterations. i'll report back after i've got these buffers built up and tried the adapters out.


----------



## leeperry

hehe, OPA2107 would be 95% as good as OPA827: OPA827, is it sonically comparable to OPA627? - diyAudio
  Quote:


 OPA2107: 95%. A worthwhile improvement on 2132.
 2 x OPA827: 100%. The best opamp I've yet tried - I suspect that for nearly every application, these will be limited only by other parts of the signal chain. 
 

I like the OPA2107AP, it used to be too clean..but as ±9V AK4396 LPF followed by ±9V Earth as final buffers, it's really nice! and no need for soldering or crappy browndogs


----------



## SpudHarris

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_hi guys, thought I would share this find with you; dont know if any of you have come accross these before and simply found them too pricey or what, but hereis where I bought some amazing little adapters of extremely high quality with several ready spots for adding resistors and caps, you'll probably need to put it through google translate from swedish. or try this link for the site put through google translate. I havent received mine yet; only ordered a coupe of days ago after finding a link from the Sjostrom audio  which has some wicked stuff ranging from the amazing SSB01 discrete level unity gain buffer thats inspired by the diamond buffer, which i'm building right now. Its a great little PCB that you guys might be able to use (no association) in your soundcards, no room in a portable amp or dac really. but yeah the adapters include single SOIC8->DIP8, DUAL SOIC8->DUAL DIP8, 2 x single SOIC8->Dual DIP8 and SOIC16->DIP8 (awesome). they all have pads for caps and resistors, as well as holes so you can pull a ground reference from below. checkem out. just thought they might work for some of you who have found the combination you are pretty happy with and would like to mount it properly. A bit expensive for breadboarding or experimentation, but the PCB and traces are substantial, so could probably take a fair few iterations. i'll report back after i've got these buffers built up and tried the adapters out._

 

Thanks Jememy, those are so cool.....


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_hehe, OPA2107 would be 95% as good as OPA827: OPA827, is it sonically comparable to OPA627? - diyAudio_

 

That is a great opinion but your posting it as you found some kind of hard evidence that supports this suggestion. For every opinion you will find others that will disagree.
 You know you could always do the tests yourself and then you would have your OWN opinion of this comparison.
 Some will say they prefer the 2107 over the 827 some will say the opposite, some will say they like neither. All opinions are valid as this hobby is subjective.
  Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I like the OPA2107AP, it used to be too clean..but as ±9V AK4396 LPF followed by ±9V Earth as final buffers, it's really nice! and no need for soldering or crappy browndogs 
	

	
	
		
		

		
			



_

 

It used to be too clean? 
 the sound of the opamp never changed so what your hearing is just the result of testing the same opamp is different circuits.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Ok I've tried the LT1124 again and yes it is missing a little magic.... I keep going back to the same OpAmps so I must be nearing the end of the journey 
	

	
	
		
		

		
		
	


	




 NOT!

 The LT1363's are just wonderfull in Class A, they just don't put a foot wrong to my ears.

 I've also dug out the OPA2107 and forgot just how nice that one was. Recon I've got OCD 
	

	
	
		
		

		
		
	


	




 just....... can't........ stop...... rollin.........._

 

OPA2107 is nice, but LT1124ACN8 is just out of this world through Earth...I'm out of speech, it feeds Earth w/ such a clean/clear/natural sound, everything's perfect(upfront vocals, bass, stereo localization, you name it!)

 it's a 1364 w/o any audible distortion whatsoever basically.

 I'll give a try at 1126 as it's a decompensated version of 1124, and that would -supposedly- help...but so far I'm stunned 
	

	
	
		
		

		
		
	


	




 LT does it again, and this one is not gonna eject until I get the 1028ACN8 
	

	
	
		
		

		
		
	


	




 That'll give some coffee to grind to my Earth/new burson(as final buffer) comparison next week


----------



## 12Bass

My experience has been that OPA2107 might be a bit better than the OPA2132, but doesn't compare to the OPA827, which, IMO, sounds more open and alive across the whole spectrum. I found OPA2107 a letdown, considering what I paid for it, as there are cheaper chips which I like better.


----------



## leeperry

you know that feeling when a new component in your chain lets you hear new stuff you had never heard before? well, that's what 1124 does to me atm...very very impressive chip through Earth 
	

	
	
		
		

		
		
	


	




 it was a bit boring by itself, though.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_My experience has been that OPA2107 might be a bit better than the OPA2132, but doesn't compare to the OPA827, which, IMO, sounds more open and alive across the whole spectrum. I found OPA2107 a letdown, considering what I paid for it, as there are cheaper chips which I like better._

 

Really? Personally I always found the 2107 to be a great opamp for details and clarity compared to others in the BB line up such as 2132,2134,2227..etc.
 The 827 is also better IMO too... Your right though the 2107 is quite pricey compared to others. IIRC, it has to do with the manufacturing process used with the model.


----------



## 12Bass

Ya... Difet.... might try it again and give it a more serious listen. Mostly I was challenging the notion that it is 95% of the OPA827.... at least not in my books.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well I have been doing some initial testing the LT1124 and have to say I am really amazed that people don't mention it more. It is indeed very detailed and lightning fast, I can't say it's a neutral sounding OpAmp as it does have a colouration of sorts that makes it an interesting listen. It's hard to put into words but it's musical and I like it a lot. I will keep it in my P3+ and try some different combo's of buffers and V/G OpAmps. The 1469's will have to wait until I have got used to the 1124, if my initial findings are anything to go by the 1469's may be gathering dust for a while yet._

 

fully agreed, major kudos for the heads up!

 even w/ fresh ears, LT1124ACN8 is really AMAZING...it does everything the LM4562 promised, but failed. totally amazing, so many details!

 Steve Hoffman said a proper vynil set up needed very clean and clean mids...well, that's exactly what 1124ACN8 does for you...you get all the 4562ish details, but w/ proper bass/natural SS and very linear trebles.

 I dearly hope I won't get bored of this one, vocals sound surreal(a la 1364, but w/o any audible distortion) and the SS is just well...hard to put into words, basically the separation is just very clear.

 my burson has been shipped, I wonder what it'll make out of it as a final buffer...but it's gonna be a riot for sure


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_fully agreed, major kudos for the heads up!

 even w/ fresh ears, LT1124ACN8 is really AMAZING...it does everything the LM4562 promised, but failed. totally amazing, so many details!_

 

Nice one 
	

	
	
		
		

		
		
	


	




, it's been a while since I tried the 1124 and I never tried it anywhere but L/R in my circuit so might check it again this evening in G/VG of the P3+.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Ya... Difet.... might try it again and give it a more serious listen. Mostly I was challenging the notion that it is 95% of the OPA827.... at least not in my books._

 

Yes, well I would say that notion is a bit off. Perhaps the guy that posted it need to learn the difference between opinion and actual fact.
 It is a great opamp for sure, especailly for I/V on the circuits I have tested but I would use a OPA827 instead.


----------



## ROBSCIX

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_hi guys, thought I would share this find with you; dont know if any of you have come accross these before and simply found them too pricey or what, but hereis where I bought some amazing little adapters of extremely high quality with several ready spots for adding resistors and caps, you'll probably need to put it through google translate from swedish. or try this link for the site put through google translate. I havent received mine yet; only ordered a coupe of days ago after finding a link from the Sjostrom audio  which has some wicked stuff ranging from the amazing SSB01 discrete level unity gain buffer thats inspired by the diamond buffer, which i'm building right now. Its a great little PCB that you guys might be able to use (no association) in your soundcards, no room in a portable amp or dac really. but yeah the adapters include single SOIC8->DIP8, DUAL SOIC8->DUAL DIP8, 2 x single SOIC8->Dual DIP8 and SOIC16->DIP8 (awesome). they all have pads for caps and resistors, as well as holes so you can pull a ground reference from below. checkem out. just thought they might work for some of you who have found the combination you are pretty happy with and would like to mount it properly. A bit expensive for breadboarding or experimentation, but the PCB and traces are substantial, so could probably take a fair few iterations. i'll report back after i've got these buffers built up and tried the adapters out._

 

They are cool. a freind asked me to use my design skills and do circuit layouts and PCB designs for some adapters that had circuit tracings for Caps, resistors etc.. Nice to see these I can point him to these instead of fabricating new ones. I also had a similar idea as many liek to use passive components for many taks when using opamps and adapters. Thanx for the link.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Nice one 
	

	
	
		
		

		
		
	


	




, it's been a while since I tried the 1124 and I never tried it anywhere but L/R in my circuit so might check it again this evening in G/VG of the P3+._

 

well, as AK4396 LPF, it's really sounding great! I wonder how it'll fare against the 1028ACN8 and AD797BN....this sure will be an interesting shoot out, still waiting for my browndogs.

 majkel says the 797B would even kill the Earth(and new burson as well?): http://www.head-fi.org/forums/f6/aud...-v-2-a-397691/

 I have my doubts, but you never know


----------



## 12Bass

Would be interesting to know how AK4396 compares with AK4393, and how much difference it makes compared with the analog output components like op amps, etc.... Not sure I have the nerve to try and replace the DA chip, however, as the pins are really tiny....

 Not sure you'd like the AD797.... as it sounds pretty neutral/uncolored/clean, and a bit laid back and dark from my experience.


----------



## leeperry

the're pin compatible, this french guy swapped them...but he said he was very surprised to have succeeded: Replacement converters

 he says the SQ is just clearer and the trebles a lot cleaner, more dynamics too.

 I'm actually looking for a very neutral/uncolored op-amp to use as AK4396 LPF to feed the Earth/Burson buffer...they color the sound and make it tubey, I'm not interested in a double dip(3*Earth sounds terrible).

 LT1124 was rather boring on its own(as LPF w/o any buffer), but the Earth makes it very appealing.


----------



## leeperry

I haven't received yet either my AD797BN or my second pair of 1028ACN8...but I got my browndogs 
	

	
	
		
		

		
		
	


	




 I'll try replacing Earth by this, to see what the fuss is all about:






 I guess I've got no other option but soldering them on the browndog...I'm already using an extra gold plated socket as riser, and this is already pretty high...not sure an additional soldered socket would fit.

 if I dared, I'd use the Audio-GD extension leads...but Andrea advised against it, it'd work w/ their discrete chips because they're slow and have caps to make up for it.

*EDIT: *talk about risers: http://www.head-fi.org/forums/f46/xo...0/index68.html

 if that "works", why would the Audio-GD extensions leads not?

 anyway movies are beyond words on the 1124+Earth, and so is 70's jamaican reggae...there's no real hurry to roll anymore


----------



## majkel

Old Burson is OPA-Earth, new Burson is OPA-Moon. Why bother? LT1028ACN8 is better in my application than the AD797B. On top of everything is a pair of OPA228P. 

 You can try a trick which is working *only* with OPA227, OPA228, LT1028 and LT1128 - short pins 1,7 and 8 all together. In other words, connect pin 1 and pin 8 to the positive power supply rail. Then tell me what you think. With the OPA228 it's an obvious improvement.


----------



## SpudHarris

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Old Burson is OPA-Earth, new Burson is OPA-Moon. Why bother? LT1028ACN8 is better in my application than the AD797B. On top of everything is a pair of OPA228P. 

 You can try a trick which is working *only* with OPA227, OPA228, LT1028 and LT1128 - short pins 1,7 and 8 all together. In other words, connect pin 1 and pin 8 to the positive power supply rail. Then tell me what you think. With the OPA228 it's an obvious improvement._

 

I really like the 228's, I'm going to try that trick this evening. Thanks for the tip majkel, I'll let you know how it seems in my application.


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Old Burson is OPA-Earth, new Burson is OPA-Moon. Why bother? LT1028ACN8 is better in my application than the AD797B. On top of everything is a pair of OPA228P. 

 You can try a trick which is working *only* with OPA227, OPA228, LT1028 and LT1128 - short pins 1,7 and 8 all together. In other words, connect pin 1 and pin 8 to the positive power supply rail. Then tell me what you think. With the OPA228 it's an obvious improvement._

 

I am a fan of the 227,228's I have never heard of what your suggesintg but will give it a try. Can I ask what this mod does?
 Wasn't the AD797B your favorite? I have many LT's I will have to look and see if the LT1028 is in there.
 I will post some impressions of I get around to testing.


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I am a fan of the 227,228's I have never heard of what your suggesintg but will give it a try. Can I ask what this mod does?
 Wasn't the AD797B your favorite? I have many LT's I will have to look and see if the LT1028 is in there.
 I will post some impressions of I get around to testing._

 

x2

 Can I also clarify some details. Do you leave all the pins in situ or bend out of the socket. I assume you leave pin 7 as is and bend 1 and 8 out and join onto pin 7. Or am I talking out my arse?: duggfloat:


----------



## leeperry

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_new Burson is OPA-Moon._

 

humm?? got anything to back up this statement please? the new burson is not made by Audio-GD and is said to be an improvement over Earth, especially vocals-wise 
	

	
	
		
		

		
		
	


	




 I hate Moon, it sounds distorted to death(both as LPF or final buffer), just like these RMAA measurements are showing: RightMark Audio Analyzer test: comparison

 and Sun is lacking some tonal nuances(as you said, before you changed your mind 
	

	
	
		
		

		
		
	


	




), it sounds cripped as hell as AK4396 LPF.

 do you think it's a terrible idea that I put AD797BN/LT1028ACN8 on browndogs(like the pic posted above)...and then use 5cm Audio-GD extension leads to install them as AK4396 LPF? if that guy put zillion DIP8 sockets on his STX as I/V, I guess I can give it a shot 
	

	
	
		
		

		
		
	


	




 or should I add caps like Audio-GD does to minimize oscillation?

 and is there any point trying decompensated op-amps as AK4396 LPF? like LT1126(decompensated version of 1124) and OPA227 you said I think?


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_x2

 Can I also clarify some details. Do you leave all the pins in situ or bend out of the socket. I assume you leave pin 7 as is and bend 1 and 8 out and join onto pin 7. Or am I talking out my arse?: duggfloat:_

 

I just looked through my collection and pulled out a pair of OPA228's in DIp8 format and popped them into an adapter. Hoping to try this out today and then try Majkel mods. I think I will go and solder up another Dual dip8 to single Dip8 unit so I have a matched set of 228's.


----------



## SpudHarris

I want to try it but need exact clarification of the mod.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I want to try it but need exact clarification of the mod._

 

Yes, I need a bit more clarification also.
 I just got finished soldering up some dual DIP8 to single Dip 8 units and I am listening to the OPA228's. I want to try this mod out on these units..


----------



## diditmyself

I have a hard time to see how such a mod could improve the sound, if the "trim pins" are in the same position in OPA22x as in LT1x28. Decreasing the value of the LTP load resistors leads to lower VAS bias. The schematics in data sheets are just simplified, and the load resistors might in fact be current mirrors. By removing the CM emitter resistors with this mod, the CM might be less balanced.


----------



## SpudHarris

I've just modded a DIP socket with pins 1 and 8 joined to pin 7. Pins 1 and 8 have then been chopped off and filed down so they don't touch anything when plugged in. Have'nt tried them yet as I wanted someone to say if this how the mod goes.

Attachment 22698

 Also soldered up another 2 OPA827's, man I love these opamps....


----------



## leeperry

ok, no need for extensions after all: 



 it barely fits, but it does fit 
	

	
	
		
		

		
		
	


	




 I'm currently listening to 2*LT1213ACN8 as AK4396 LPF and 2*LT1028ACN8 as final buffer(all fed w/ ±8.8V):





 had to use one riser on the 1028's otherwise the red WIMA cap would get in the way...well, the 1028's sound like IC's, they clearly cannot touch the Earth as buffer w/ their uber-wide SS/high definition...well, all the fluff you can read on the burson page basically: Burson Opamp





 I'll wait a bit and put back the Earth, this one is amazing...and I have a hard time believing that the new burson is Moon, majkel must be mistaking...this looks nowhere like a Moon:






 photo of Moon: http://www.head-fi.org/forums/5645928-post146.html

 so it'll boil down to :
 -AK4396 LPF: 4*LT1028ACN8/4*AD797BN/4*OPA228P/4*OPA227P, to get a nice and clear DAC output
 -final buffer: 1*Earth/1*new burson, to get a nice tubey sound

 and if all that fails, the LPF candidates will be LT1632/LT1211/LT1215/LT1630 
	

	
	
		
		

		
		
	


	




 LT1124 is nice, but what it gives in the trebles...it seems to take it off from the low end bass


----------



## SpudHarris

Well I must have the OPA228 mod wrong because although they still sound good, I definately preferred them without the adapers I knocked up. I'm still in love with the OPA827's. At least until my ADA4627's get here (they were despatched 2 days ago)


----------



## igor0203

I'm currently listening LT1632 and I must admit it sounds good.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well I must have the OPA228 mod wrong because although they still sound good, I definately preferred them without the adapers I knocked up. I'm still in love with the OPA827's. At least until my ADA4627's get here (they were despatched 2 days ago)_

 

I thought you were waiting for Majkel instructions on this mod?


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I thought you were waiting for Majkel instructions on this mod?_

 

Curiosity got the better of me. I will try again if I have it wrong though as I've always liked the OPA228's.


----------



## leeperry

ahhhhhhhhhhhh, 2*LT1213 + Earth = 
	

	
	
		
		

		
		
	


	




 when I read ppl saying that some IC's can sound better than Earth as buffer, I think they really need to try them in other designs..

 everything's miiiiiiiiiiiiiles better, SS, details, separation...use a discrete for 1 week, then put back your favorite IC...it won't stay long, I can tell you that


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Curiosity got the better of me. I will try again if I have it wrong though as I've always liked the OPA228's._

 

I actually didn't hink I had any around. Then I looked at seen I have a tube of them. Lucky me I also have 3 unbuilt adapters from converting them for use in my circuits. So I am enjoying them also right now, those and a few other single channel Dip8's. Let me know if you get the mod sorted out properly.


----------



## Apocalypsee

I couldn't believe it, Linear DID send me my requested sample, I ordered 2 at the same time, LT1028 and LT1224. Testing LT1028 currently, so far I liked what I hear 
	

	
	
		
		

		
		
	


	




 It sounded very 'open' with wide soundstage


----------



## leeperry

humm OPA2132P is still a major winner on DAC output, and Earth as final buffer magnifies it even further...it seems to sound like an IC/discrete hybrid, that's always the feeling I've had. Even Kingwa told me that he very much likes this chip.


----------



## ROBSCIX

Quote:


  Originally Posted by *Apocalypsee* /img/forum/go_quote.gif 
_I couldn't believe it, Linear DID send me my requested sample, I ordered 2 at the same time, LT1028 and LT1224. Testing LT1028 currently, so far I liked what I hear 
	

	
	
		
		

		
		
	


	




 It sounded very 'open' with wide soundstage 
	

	
	
		
		

		
		
	


	


_

 

I found they are pretty good if you don't bother them all the time.


----------



## ecclesand

I soldered up some OPA827s on single adapters for my Lite DAC-AH. I just recently went thru it and replaced all the electrolytic capacitors with better quality ones. Also replaced the film caps and resistors in the signal path with better ones. What a difference! Anyhoo...I replaced my OPA627s with the OPA827s and jeez louise...the bass is very boomy. Granted, I've had them in for only 15 minutes now, but does the bass tighten up with some burn-in?


----------



## ROBSCIX

I never noticed boomy bass on my testing circuits.

 Did you do all the moding before you added the opamp?
 Just mean perhaps it is the caps that are influencing the bass, maybe not.


----------



## igor0203

After some tests, I found that OPA2107 is much better than LT1632. LT is much more "closed", muddy and with sloppy bass. 
 I still have to put LT1819 on SOIC adapter, OPA827 os browndogs... 
	

	
	
		
		

		
		
	


	




 And can't decide between LT1364 and OPA2107. Each one has it's qualities.


----------



## leeperry

I'm having a blast w/ LT1469IN8(engineered to be used on DAC output)...very nice through Earth, 2132P was great but a tad too dark


----------



## 12Bass

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I soldered up some OPA827s on single adapters for my Lite DAC-AH. I just recently went thru it and replaced all the electrolytic capacitors with better quality ones. Also replaced the film caps and resistors in the signal path with better ones. What a difference! Anyhoo...I replaced my OPA627s with the OPA827s and jeez louise...the bass is very boomy. Granted, I've had them in for only 15 minutes now, but does the bass tighten up with some burn-in?_

 

Interesting.... I've found the OPA827 to have a satisfying, but not overbearing, amount of low frequencies, and nicely balanced across the frequency spectrum. From what I've read, I would have thought that the OPA627 would be a bit darker sounding. Did you compare them both after the modifications?


----------



## 12Bass

Are there any electrolytics in the signal path? If so, I've noticed an increase in clarity/transparency by using a small polypropylene capacitor as a parallel bypass.

 FWIW, I've never noticed much change in sound in op amps over time. My experience has been that their sound is usually apparent as soon as they are installed in the circuit.


----------



## ROBSCIX

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_After some tests, I found that OPA2107 is much better than LT1632. LT is much more "closed", muddy and with sloppy bass. 
 I still have to put LT1819 on SOIC adapter, OPA827 os browndogs... 
	

	
	
		
		

		
		
	


	




 And can't decide between LT1364 and OPA2107. Each one has it's qualities._

 

The OPA2107 is a very great sounding opamp and Persoanlly I would take it over the LT1364 but that is just my preference based on my testing.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Interesting.... I've found the OPA827 to have a satisfying, but not overbearing, amount of low frequencies, and nicely balanced across the frequency spectrum. From what I've read, I would have thought that the OPA627 would be a bit darker sounding. Did you compare them both after the modifications?_

 

I found the same and mentioned it earlier. I found the OPA827 to have a very balanced bass response. Possibly something else in the modifications?

 You got improved sound on the OPA827 from bypass cap, can you elaborate on the modification and what you heard after the addition?


----------



## ecclesand

The low end of the OPA827 has tightened up quite a bit and they are actually very good. I find them a touch smoother than the OPA627 with the upper end rolled off ever so slightly. I need to give them more time to see what further changes they go thru.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_The low end of the OPA827 has tightened up quite a bit and they are actually very good. I find them a touch smoother than the OPA627 with the upper end rolled off ever so slightly. I need to give them more time to see what further changes they go thru._

 

Mayeb the difference your hearing has to do more with the burn in of the new capacitors? Anyway, everybody in this thread that has tested them enjoys them and nobody yet has suggested they have overbearing bass so There must be another aspect at work here.
 Great your circuit is starting to balance out now after all your mods!


----------



## crapback

I have to recommend some k40y9 bypass caps cause I absolutely love the things in my zero. They completely un-neutered both the dac and amp sections.


----------



## Apocalypsee

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I found they are pretty good if you don't bother them all the time._

 

I don't catch what you trying to say. So far I like how it sounds, its very spacious, may be a bit bright and slight edginess but thats fine with me, even Crysis Warhead sounds great with them, I have a blast playing with it 
	

	
	
		
		

		
			





 LT1224 comes out next, will post it when I listen to them


----------



## Apocalypsee

LT1224 is in, and what a surprise! Immediately I can hear the differences, and its HUGE! Its very clean, very deep and clean background. It goes well with my bright Monitor Audio speakers and Technics amp.

 If the LT1028 displays all the detail forward, this one is more laid back. More pleasing to my ear, no edginess, roughness. Just clean, dark background and great vocal. Pleasing to my ear. Its pitch perfect I must say, precise, good stereo separation and pretty tight bass. Its like each instruments, vocal, background vocal have its own layers 
	

	
	
		
		

		
		
	


	




 Although its great on speaker, on my HD-437 it sound restricted and tinny. Its not suitable for headphones I guess


----------



## 12Bass

Replaced the LM4562 (originally was NJM2068) in the output of my Echo Mia with an OPA1612 and it sounds better than before as far as I recall.... Though I've installed an OPA827 in my NAD 3150 and made a few other modifications since last time the Mia was in use, including adding a couple of paralleled polypropylene bypass capacitors to the high pass section of the crossovers in my Energy Pro22 monitors. 

 Although I've found that I preferred the sound of using two single op amps on an adapter in direct comparisons, sometimes it simply isn't practical and a dual must be used. Replacing SOIC dual op amps in a tight space on a sound card is one of those times.... 

 I don't remember the Mia sounding this good before... in comparison the Gina24 is a bit better sounding, in part because of more stable clock (Mia's sound quality improves if clocked from the Gina), and in part because it uses a separate a chip for DA (AK4393) rather than an integrated CODEC (AK4528) for both AD/DA. I'm using the Mia currently because the Gina24's headphone volume pot needs to be replaced and because the RME DIGI96/8 PST doesn't work in Vista64. One nice feature of the Mia is that it has eight virtual outputs and supports simultaneous multi-client operation, so you can run ASIO on two channels and have six more output channels free for other uses.

 At less than 2/3 the cost of the OPA2211A, the OPA1612 has equal, or almost equal, sonic performance, and is a good choice where a low noise, dual, bipolar op amp is required, IMO. Current consumption is reasonable too, and it appears to be well behaved. DC offset with the output capacitors shorted is only 7 mV.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Replaced the LM4562 (originally was NJM2068) in the output of my Echo Mia with an OPA1612 and it sounds better than before as far as I recall.... Though I've installed an OPA827 in my NAD 3150 and made a few other modifications since last time the Mia was in use, including adding a couple of paralleled polypropylene bypass capacitors to the high pass section of the crossovers in my Energy Pro22 monitors. _

 

 I like the 161X series but found I like the 1611 dual SOIC's adapted to DIP8.
  Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Although I've found that I preferred the sound of using two single op amps on an adapter in direct comparisons, sometimes it simply isn't practical and a dual must be used. Replacing SOIC dual op amps in a tight space on a sound card is one of those times.... _

 

 Yes they can be impractical for many reasons. I am in agreement that for my tests I will take a dual single channel module over a single dual channel module. However, there are many reasons why you cannot use them all the time. A freind sent me a unique adapter the other day; It takes a dual DIP 8 and adapts it to a single channel Dip8. I have many uses for it and want to get more. I figured these may be of use to some of you guys that need single channel DIP8 for your DAC's/headphone amplifiers...etc.
  Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_I don't remember the Mia sounding this good before... in comparison the Gina24 is a bit better sounding, in part because of more stable clock (Mia's sound quality improves if clocked from the Gina), and in part because it uses a separate a chip for DA (AK4393) rather than an integrated CODEC (AK4528) for both AD/DA. I'm using the Mia currently because the Gina24's headphone volume pot needs to be replaced and because the RME DIGI96/8 PST doesn't work in Vista64. One nice feature of the Mia is that it has eight virtual outputs and supports simultaneous multi-client operation, so you can run ASIO on two channels and have six more output channels free for other uses._

 

 You have many recording interfaces, do you do home recording?
 I have a closet full of recording gear and record all the time.
  Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_At less than 2/3 the cost of the OPA2211A, the OPA1612 has equal, or almost equal, sonic performance, and is a good choice where a low noise, dual, bipolar op amp is required, IMO. Current consumption is reasonable too, and it appears to be well behaved. DC offset with the output capacitors shorted is only 7 mV._

 

The 16XX series seeom pretty god based on my testing and what others have posted I am surprised more here are not using or atleast cheking it out.


----------



## 12Bass

Funny that.... why yes! I do some recording, and have mixed a few projects. My first recording interface was the Echo Mia, followed later by the Gina24. The DIGI96/8 PST came in a PC which I built a few years ago for the drummer from the Northern Pikes. He switched to Macs and gave it back to me.....


----------



## ROBSCIX

Great stuff.


----------



## igor0203

I've installed OPA827 on browndogs and all I can say is WOW 
	

	
	
		
		

		
		
	


	



 It's better than any opamps I have tried so far. Better than OPA2107, LT1364, LME49720.


----------



## ROBSCIX

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_I've installed OPA827 on browndogs and all I can say is WOW 
	

	
	
		
		

		
		
	


	



 It's better than any opamps I have tried so far. Better than OPA2107, LT1364, LME49720._

 

Yes, they have been getting great reports in this thread from the people that have actually tested them.


----------



## SpudHarris

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_I've installed OPA827 on browndogs and all I can say is WOW 
	

	
	
		
		

		
		
	


	



 It's better than any opamps I have tried so far. Better than OPA2107, LT1364, LME49720._

 

Good for you 
	

	
	
		
		

		
		
	


	




 I love the 827's soooooo much I don't think I'll ever find another Opamp that ticks the amount of boxes they do, for me anyhow.


----------



## 12Bass

Interesting..... I'm curious.... how would you all characterize the sound of the OPA827?


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Interesting..... I'm curious.... how would you all characterize the sound of the OPA827?_

 

Do you not like the OPA827's?


----------



## SpudHarris

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Interesting..... I'm curious.... how would you all characterize the sound of the OPA827?_

 

One word - Beautiful!


----------



## igor0203

Only thing I noticed is that it's little shy on bass and doesn't go as deep as LT1364. Otherwise it's perfect. Clean, dynamic, fluid sound.


----------



## leeperry

yep, OPA827 had a major lack of low end bass when I tried it..


----------



## SpudHarris

Well, I really think it depends on the application and of course what you are listening through. I can tell you that I am using these In a P3+ with Hi-C Buf634's in the buffer section & LME49710HA's in ground/Vground with my JH13 IEM's and these are anything but shy of lower frequencies 
	

	
	
		
		

		
		
	


	




. In fact they are not shy of any frequencies, this set up was a match made in heaven 
	

	
	
		
		

		
		
	


	




 I have had some real late nights recently because I can't stop listening with this set up and I've had the same set up for quite a few weeks now, it still gives me goose bumps


----------



## leeperry

good point, I only tried them as final buffer...I'll try them as AK4396 LPF whenever I'll get those adapters from HK, that are supposedly better than the browndogs..

 but the ability to put 4*single DIP8 on my soundcard has made me kinda lazy w/ soldering...especially w/ the AD797BN/LT1028ACN8 still pending a try


----------



## 12Bass

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Do you not like the OPA827's?_

 

Nah.... haven't you read my posts? 
	

	
	
		
		

		
		
	


	




 Just curious to know what others think about how it sounds. I like it in most applications where I've tried it. Haven't noticed a lack of bass either.... though I do think that the LM/LME family sounds a bit thin at times. OPA827 seems to have most everything covered, IMO, although it isn't quite as open/transparent as some of the high speed op amps. AD825 might have a bit more of a colored, "scooped", sound with boosted bass and treble, for those with that sort of preference.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well, I really think it depends on the application and of course what you are listening through. I can tell you that I am using these In a P3+ with Hi-C Buf634's in the buffer section & LME49710HA's in ground/Vground with my JH13 IEM's and these are anything but shy of lower frequencies 
	

	
	
		
		

		
		
	


	




. In fact they are not shy of any frequencies, this set up was a match made in heaven 
	

	
	
		
		

		
		
	


	




 I have had some real late nights recently because I can't stop listening with this set up and I've had the same set up for quite a few weeks now, it still gives me goose bumps 
	

	
	
		
		

		
		
	


	


_

 

Yes and it would also have to do with what your listening with. Some use headphones that are more bass heavy or birghter..etc. The circuits is the major factor also though.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Nah.... haven't you read my posts? 
	

	
	
		
		

		
		
	


	




 Just curious to know what others think about how it sounds. I like it in most applications where I've tried it. Haven't noticed a lack of bass either.... though I do think that the LM/LME family sounds a bit thin at times. OPA827 seems to have most everything covered, IMO, although it isn't quite as open/transparent as some of the high speed op amps. AD825 might have a bit more of a colored, "scooped", sound with boosted bass and treble, for those with that sort of preference._

 

They are good but I like many opamps.


----------



## majkel

The 1-8-7 mod is to increase bias currents of the input stage. Just short the pins all together, or feed B+ to 1 and 8, just like it's done to pin 7. I'm not sure it improves the LT1028 while the change is obvious but it surely improves the already great OPA228.


----------



## SpudHarris

Could you post a picture at all? I'm struggling with the finite detail..... Do you leave all the pins as they are so they all insert or do you bend all or some out before shorting them together.

 I tried what I thought was right but didn't like the sound.


----------



## majkel

Use a piece of wire and solder it from pin 1 to between pins 7 and 8. Just make a bridge over the chip and solder the wire to the wider part of the pins so that you can still insert them properly. This mod doesn't apply to many other op-amps or might even damage them. OPA228 and LT1028 are OK. Something equivalent for the AD797 is shorting pins 1,4 and 5 but you need to surround the chip with the wire. Sound gets cleaner and softer.


----------



## SpudHarris

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Use a piece of wire and solder it from pin 1 to between pins 7 and 8. Just make a bridge over the chip and solder the wire to the wider part of the pins so that you can still insert them properly. This mod doesn't apply to many other op-amps or might even damage them. OPA228 and LT1028 are OK. Something equivalent for the AD797 is shorting pins 1,4 and 5 but you need to surround the chip with the wire. Sound gets cleaner and softer._

 

Ahhh right, so no need to snipp off any pins then? That's where I went wrong


----------



## ROBSCIX

Will have to give that a try when I get time.


----------



## SpudHarris

Done it and yes I have to say it does make a difference. It will take me a while to put it into words but I like it so far.


----------



## diditmyself

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Something equivalent for the AD797 is shorting pins 1,4 and 5 but you need to surround the chip with the wire. Sound gets cleaner and softer._

 






 I don't think there's a detailed official AD797 schematic, but the above is said to be the real deal. I think the offset trim probably is at R5/R7 - at the emitters of the VAS current mirror. By connecting the current mirrors directly to V- you bypass the floating current mirror concept, and the opamp will not be an AD797 anymore. You definately wont get higher bias to the input stage nor the VAS. I don't think it can operate this way at all.

 The above picture seems to have bene censored, or just lost. This is the official simplified schematic:






 The offset trim is probably at the emitters of Q5 and Q6, the VAS current mirrors. In this simplified schematic it's clear to see that you can't just connect those emitters to V-. Even if the current mirror wasn't floating, there would be nothing to gain from bypassing the emitter resistors. It would just make the current mirror less balanced.


----------



## diditmyself

Regarding the LT1028 mod. By connecting the trim pins to V+ you change the LTP load resistors from 3130 to 3000 Ohm. This wont increase the input stage (LTP) bias. This bias is set by the CCS (Q3/R7/Q15/R8).


----------



## leeperry

hehe, since reading majkel saying that the new burson is the exact same as Moon(which is utter bs), that AD797B doesn't exist in DIP8 and more funny judgments about discrete op-amps....I've learned to take his words w/ a grain of salt 
	

	
	
		
		

		
		
	


	




 I suggest modders to do so as well, better be dubious than sorry...you can find some simplified schematics for the AD797 there: AD797BN pdf ::: ALLDATASHEET :::


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Done it and yes I have to say it does make a difference. It will take me a while to put it into words but I like it so far._

 

with the 228's?
 What are you hearing?


----------



## ecclesand

Got the ADA4627s earlier today and soldered them on some adapters. Anymore it takes longer for the iron to heat up than to actually solder them. I'm liking them so far...very clean sound with a black background. I'm using them in conjunction with some Hi-C BUF634s as a headphone amp driver.


----------



## majkel

@leeperry - AD797BN is not produced any more because it's not RoHS compliant. European vendors don't sell it and it's obsoleted. 

 The statement that Moon = Burson v.2 is in the Opamp Distortion document from SGacoustics.com Just read it. The guy compared the schematics of both. 

 I am sorry for people having equipment in which artifacts and colorations from Audio-GD OPA's bring improvements. See the Opamp Distortion document for their distortion numbers. It's bigger than of typical tube stages and not of the tube kind. I still admit the OPA's are amongst the best sonic choices but I will never agree they set a new level of quality.

 Regarding the trim pins trick - we know nothing about the OPA228 and the AD797 schematic how it is done. For the LT1028 - I can agree it does not change the bias currents but decreases the input stage amplification a bit and increases the B-C junction headroom a bit. I also think that the change is a disputable improvement. For the OPA228 I like what I hear and I can make a quick comparison with an unmodded pair. So I'm sure of my impressions. The sound is more open and free of a slight nasal coloration which my friend also heard in my rig.


----------



## SpudHarris

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_Got the ADA4627s earlier today and soldered them on some adapters. Anymore it takes longer for the iron to heat up than to actually solder them. I'm liking them so far...very clean sound with a black background. I'm using them in conjunction with some Hi-C BUF634s as a headphone amp driver._

 

Hey Doug, getting mine today via DHL (fingers crossed).

 ROBSCIX - Yes the 228's. Hmmm, not quite sure how to describe the changes in sound. Probably cleaner and punchier, not as laid back if you like. Not sure if I like it more or less, it's just different.


----------



## leeperry

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_The statement that Moon = Burson v.2 is in the Opamp Distortion document from SGacoustics.com Just read it. The guy compared the schematics of both. 

 I am sorry for people having equipment in which artifacts and colorations from Audio-GD OPA's bring improvements. See the Opamp Distortion document for their distortion numbers. It's bigger than of typical tube stages and not of the tube kind. I still admit the OPA's are amongst the best sonic choices but I will never agree they set a new level of quality._

 

well, IC's(like 1028ACN8 or so) bring a boring L/R SS...Earth provides you w/ a *stunning* 3D-ish SS(on my cd1k at least, same drivers/construction as cd3k), some casualties are meant to be expected!

 in "District 9", the helicopters were literally turning around my head...no IC *whatsoever* will ever provide you w/ this kind of SS, same goes for the barbershop demo when he's at the back of your head w/ the trimmer 
	

	
	
		
		

		
			





 And Andrea already pointed me to this PDF, it says that the burson "mk2"(now what's "mk2"?) has identical distortion figures to earth(not moon)...that's something we've been very well aware of.

 anyway, I'm getting a new burson this week, if it's even better than Earth as final buffer, it'll be a keeper for sure..I'll feed it w/ some 1028ACN8/OPA228P or AD797BN


----------



## 12Bass

Did a bit more listening to OPA827, OPA211, and OPA1611 in the preamp of my (modified) Eden bass amplifier. Although I've preferred the sound of the OPA827 in other applications, I thought that the OPA211 had a more clear and direct sound in the part of the circuit where I was testing. In contrast, the OPA827 sounded somewhat soft, a bit midrangey, and slightly less detailed. When I popped the OPA211 back in, it sounded better to me. Once again I compared the OPA1611 to OPA211 and thought that OPA211 sounded a little better - more transparent somehow. Perhaps it is worth noting that I'm seeking a mix of both transparency and pleasing coloration in reproducing the sound of my instruments.


----------



## 12Bass

A pair of OPA827s on a BrownDog adapter, with a 0.01 µF capacitor across the power rails.


----------



## ecclesand

Quote:


  Originally Posted by *comic* /img/forum/go_quote.gif 
_I'd be eager to try the ADA4627-1, but there's no way to buy it yet. It's the only opamp left that could challenge my favorite LT1028CS8._

 

I bought the ARZ versions direct from AD. 

 You seem to make a few statements as fact. The LT1028 is NOT perfect sounding. It may be to your ears and in your circuit but I'm sure others will disagree with you...myself included.

 He's baaaack!


----------



## qusp

so i've got some LME49720HA on the way for something interesting. got the 20 rather than the 10, although I usually prefer to get 2 singles, as it makes for easier modding, but I get more for my postage dollar with dual samples 
	

	
	
		
		

		
		
	


	




 interesting to note they only allow samples of a single device rather than Ti and AD's open house for prototyping. anyone know whether they will operate under the stated minimum current of 2.5+-?? some opamps will work quite nicely and be stable under their st6ated minimum supply voltage, but others are rather cranky

 also, looking for a quality low voltage differential input and output opamp for a DIY balanced DAC based on the PCM1794A or more likely 1798 due to being more efficient. have some OPA1632 on the way as soon as they catch up on orders, but that wont be for a month or so, any alternatives in the same class you guys know about?? plenty of opamps with differential inputs, but many have SE output only


----------



## ROBSCIX

I find out of those units the 10HA as favorable over the 20HA's...but I fine many single are preferable over duals.
 I am unsure about the current requirments.


----------



## ecclesand

To my ears, the ADA4627 is the real deal. The music flows so effortlessly with them as both line driver for a CS4398 DAC and paired with HI-C BUF634s as a headphone amp. All my testing has been with the ARZ version as the BRZ were more expensive. I think I may need to pick up a couple BRZ versions for comparison.

 In my Lite DAC-AH, I switched back to the opa627 from the opa827. To my ears, the opa627 bests the 827 in every category. However, I need to pick up a few more ADA4627s and mount them on single adapters to try in the Lite. These may just beat the opa627 in this circuit.


----------



## ROBSCIX

..another added to my list. I am going to need another opamp case soon
	

	
	
		
		

		
		
	


	




 ..Ah OPA637SM...ever try those?


----------



## diditmyself

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Regarding the trim pins trick - we know nothing about the OPA228 and the AD797 schematic how it is done._

 

I have what I think is the real AD797 schematic. I don't know why it was removed. I can put it up again. I can see no other way of trimming the DC offset by connecting 10k resistors to V-. It has to be on the CM emitters.


----------



## qusp

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I find out of those units the 10HA as favorable over the 20HA's...but I fine many single are preferable over duals.
 I am unsure about the current requirments._

 

like I said, so do I, but for ease of use and current requirements I got duals this time; got the metal cans, never used them before actually, other than shielding what advantage do they have over DIp and soic?? also if you guys could have another glance at my post ^^ I had edioted it but forgot to finish; wondering if you guys have much info on differential in/out opamps in the same class as OPA1632 for a possible portable balanced DAC project using discrete buffers?? seems the only way i'm gonna get balanced output on the go is to do it myself 
	

	
	
		
		

		
		
	


	




 OPA1632 sound great in my buffalo32, but are a bit higher current than I would like and also Ti wlont catch up with production for a month or so when mine will ship


----------



## Pluto2

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_A pair of OPA827s on a BrownDog adapter, with a 0.01 µF capacitor across the power rails.




_

 

Hi 12bass, did you also put in a bypass cap at the bottom chip? neceesary?


----------



## SpudHarris

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_To my ears, the ADA4627 is the real deal. The music flows so effortlessly with them as both line driver for a CS4398 DAC and paired with HI-C BUF634s as a headphone amp. All my testing has been with the ARZ version as the BRZ were more expensive. I think I may need to pick up a couple BRZ versions for comparison._

 

Doug I'm with you there buddy, man these are something else. It's not very often that an opamp has so much immediate appeal but these are just awesom. In the same set up as the OPA827's (Hi-C Buf634's and LME49710HA's in ground) these just excel with electronica/trance. Got a feeling tonight is gonna be a late one............

 These are expensive and a pain to get as samples but you guys have to try them.


----------



## 12Bass

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Hi 12bass, did you also put in a bypass cap at the bottom chip? neceesary? 
	

	
	
		
		

		
		
	


	


_

 

Not sure the bypass across the rails is actually necessary at all.... mostly there right on the chip just in case of possible instability. I've usually already put bypasses on each rail in the circuit. And, to answer your question, no, I just use a capacitor across the rails on the top chip. Too much hassle to do the bottom one with BrownDogs. However, sometimes I'll put a capacitor beneath the socket if I solder an SOIC part to a DIP socket.


----------



## 12Bass

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_To my ears, the ADA4627 is the real deal. The music flows so effortlessly with them as both line driver for a CS4398 DAC and paired with HI-C BUF634s as a headphone amp. All my testing has been with the ARZ version as the BRZ were more expensive. I think I may need to pick up a couple BRZ versions for comparison.

 In my Lite DAC-AH, I switched back to the opa627 from the opa827. To my ears, the opa627 bests the 827 in every category. However, I need to pick up a few more ADA4627s and mount them on single adapters to try in the Lite. These may just beat the opa627 in this circuit.
	

	
	
		
		

		
			



_

 

Interesting.... will have to look into the ADA4627. Wasn't all that impressed with ADA4841-1.

 What is the application where you're using OPA627/827? I haven't heard OPA627 yet, however, a number of people have said that it is too laid back and that the OPA827 is superior. Of course, my own experience has shown that the application can make a big difference, as I've found that I prefer other chips in certain circuits.

 On a side note, posts are not taking a minute to process today. For the past while my browser would time out for a long time before the post would show up, which can be very annoying if any edits are necessary. Faster = good!


----------



## ecclesand

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Interesting.... will have to look into the ADA4627. Wasn't all that impressed with ADA4841-1.

 What is the application where you're using OPA627/827? I haven't heard OPA627 yet, however, a number of people have said that it is too laid back and that the OPA827 is superior. Of course, my own experience has shown that the application can make a big difference, as I've found that I prefer other chips in certain circuits.

 On a side note, posts are not taking a minute to process today. For the past while my browser would time out for a long time before the post would show up, which can be very annoying if any edits are necessary. Faster = good!_

 

I'm using the OPA627 as output drivers for my modded Lite DAC-AH which is a NOS DAC with 8 TDA1543 chips. In this setup, the opa827 sounded laid back compared to the opa627.

 I have some nice Auricaps on order to do a passive output. I plan to add another set of RCA jacks with the Auricaps and keep the opamp output to the existing RCA jacks. With this approach, I can test both by simply swapping RCA jacks. Hopefully I will like the passive output better so I can stop rolling opamps...at least on my primary source. I'll still roll on my other DAC/Amps.


----------



## leeperry

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I am sorry for people having equipment in which artifacts and colorations from Audio-GD OPA's bring improvements. [..] I still admit the OPA's are amongst the best sonic choices but I will never agree they set a new level of quality._

 

Hot-Rod Soundcard in true audiophile colors!!! Is this it? - Page 3 - Overclock.net - Overclocking.net Quote:


 it sounded just amazing. The three dimensional sound stage is amazingly real.


----------



## leeperry

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Perhaps it is worth noting that I'm seeking a mix of both transparency and pleasing coloration in reproducing the sound of my instruments._

 

indeed, we have different goals...most ppl on this thread want an all-in-one chip, I'm seeking the cleanest/uncolored chip available to feed my Earth/Burson final buffer(that are colored to death).

 so far I'm trying two silly NJM4580D on the AK4396 output(as ±8.8V LPF), and I like what I'm hearing! on french forums they say that this chip is basically like a piece of wire....that's what it sounds like to me, far less colored than anything I've tried so far. 

 ppl usually ditch'em for 4562's or so, but it's got a high SNR, a low THD and sounds very much 1:1 to me....this 4580 is really one nice little chip, at whatever driving headphones or filtering DAC outputs...fire and brimstone!


----------



## leeperry

hah, distortion is so damn low on the AD797:  Waveform distortion / edited Amplifier


----------



## 12Bass

Hmmm.... have listened to NJM4580s in my Behringer UB1204-PRO and RME DIGI96/8 PST, and found them somewhat edgy and lacking detail.... wouldn't say they were transparent "like wire" at all. Haven't preferred any of the JRC/NJM parts I've heard (NJM2068/2100/4580), and have found what I thought to be superior replacements from a number of other manufacturers. 

 I experienced a significant improvement in the UB1204's preamps when I replaced the NJM4580s with AD8599s and LM4562s (clearer, cleaner, more natural). I even directly compared modded and unmodded channels and had friends do blind comparisons to confirm. IMO, the OPA211/2211A is closer to the goal of transparency, or AD797 for something a bit warmer, but very clean. For driving headphones, I again recommend looking into AD8397. Thinking I might replace the op amps in the mixer with OPA2211As instead, as I prefer them to the current op amps (above).


----------



## leeperry

yeah ok, it's also very much dependent on the circuit design anyhow...and I've just added a link while you were typing this, indeed AD797 looks scarily undistorted 
	

	
	
		
		

		
		
	


	




 my four AD797BN have finally been shipped today, can't wait! I hope the browndogs won't ruin the whole thing 
	

	
	
		
		

		
		
	


	




 NJM4580D sounds better than LT1469IN8 to feed Earth I think, less colored...it's supposed to be the low noise version in that famous NJM serie.

 oh, and I can't bear the 4972x sound anyway...bass shy and bright is not my thing.


----------



## leeperry

and there's still that theory that all the music we're listening to has gone through zillions of 553x chips...you can dig for more details, but did the sound engineer even care for them? it'd be like increasing the trebles while listening to vynil.

 many highly trained sound engineers find the 553x to be the best chips...they make everything sound good, as everything we're listening to has been engineered on those.

 I'd be like watching SMPTE-C calibrated movies on a wide gamut display...more saturated colors? most definitely! but is that how these movies have been mastered/calibrated? no.

 it's like all these flat screen owners who max. the sharpness, and everything looks like clay animation...oh it's sharp ok!

 many great sounding chips do wonders on some records, and fail bigtime on others....we've all felt that, don't lie to me


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_Hot-Rod Soundcard in true audiophile colors!!! Is this it? - Page 3 - Overclock.net - Overclocking.net



_

 

Yes, well your just posting another persons opinion. It is NOT a fact.


----------



## majkel

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_Hot-Rod Soundcard in true audiophile colors!!! Is this it? - Page 3 - Overclock.net - Overclocking.net



_

 

Hey, it's just a mere PC sound card. Not that reliable test platform IMHO. My friend switched from "rolled" HD2 to E-MU 1212m and noticed quite a big improvement. My another friend switched from 1212m to CS4398 upsampling DAC, kind of more sophisticated than mine due to on-board upsampler (improving nothing as people say), and also noticed significant improvement, even before he started op-amp rolling. Try a decent stand alone DAC with a good USB or let the E-MU 1010 deliver the bits via optical output to you.


----------



## LuciferX

Can somebody tell me the differences in Bass, Mids an Highs between OPA2132P and OPA2107AP?

 Im hearing 4xOPA2132 now, has more bass and less harsh highs than my soundcard defaults (Claro Halo with 4x4580 (JRC) ), the voice has more ... Body? So far so good!

My SoundCard


----------



## leeperry

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Hey, it's just a mere PC sound card. Not that reliable test platform IMHO. My friend switched from "rolled" HD2 to E-MU 1212m and noticed quite a big improvement._

 

tell him his next upgrade is to fit some burson/earth on the HD2(and some better caps like on my Advance Deluxe version) 
	

	
	
		
		

		
		
	


	




 he was prolly using something along the lines of LT1364/AD8599 or so. USB/SPDIF have their problems too, like jiiiiittterrr and no KS support...besides the HD2 drivers(if you have the korean firmware) forbid SRC, I like that 
	

	
	
		
		

		
		
	


	




 I'm quite sure 4*AD797BN and a new burson(+mundorf cap) will sound good to me 
	

	
	
		
		

		
		
	


	




 but so far 2*NJM4580D + Earth sound really great, it sounds like just the right chip...like perfect gamut matching on a projector, saturation/hue seem spot-on. digging for more details on the DAC output might not be the wisest thing to do, as this will color the sound and benefit some songs but make some other sound really bad.


----------



## majkel

I replaced the NJM4580 with the AD8022 long time ago in my CD player at the output stage, and I noticed improvement in resolution and timbre accuracy. For the OPA-Earth sonic qualities the NJM4580 will be the bottleneck. AD8022 sound is close to that of AD797ANZ AFAIR.


----------



## K3cT

I have AD797BRZ, AD843JNZ, AD825ARZ, LT1028ACN8, and LT1124ACN8 on the way to play with my DIY amp. 
	

	
	
		
		

		
		
	


	




 So far the combo of OPA637BPs in signal and OPA627BP in ground is doing a marvelous job so the standard is pretty high. I want to avoid the discrete HDAM route because of casing complication.


----------



## leeperry

yes, agreed...vocals have less resolution, but "bottleneck"...compared to what?

 sound engineers use mostly 5532 or 2680 on pro gear...so if you use anything w/ more resolution, you're basically not hearing what they heard at the recording/mastering stages.

 like all the bluray's that are actually mastered on SMPTE-C CRT's, you sure can watch them in REC.709...but they carry SMPTE-C primaries and look over-saturated on REC.709(luckily you can convert gamuts, though ^^).

 I've tried a lot of op-amps on the DAC output, and none of them seemed to "work" on all the songs all the time...mostly because they're digging too deep IMHO, and the guy who said that to me very much has the goldenest ears I know of(he runs a Lynx Two-B, that has 5532).

 he also has a cd3k on an external amp(can't remember which) and after extensive rolling, he put back the 5532 as well.


----------



## ROBSCIX

Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_Can somebody tell me the differences in Bass, Mids an Highs between OPA2132P and OPA2107AP?

 Im hearing 4xOPA2132 now, has more bass and less harsh highs than my soundcard defaults (Claro Halo with 4x4580 (JRC) ), the voice has more ... Body? So far so good!

My SoundCard_

 

Personally I would take the 2107AP over the 2132 but the 2107 is not for everybody. Happy testing.


----------



## leeperry

and the Benchmark DAC1 is also full of 5532's...ironic, isn't it?


----------



## crapback

Aren't the Benchmark's opamps soic's soldered directly on the board? I've been comtemplating saving up for one of those but I want to be able to opamp roll especially to try some hdams. I've been looking at all the pics I can find and I don't see and DIP's anywhere. Anyone know for sure?


----------



## leeperry

I don' think you wanna void the warranty of such a pricey piece of equipment..


----------



## leeperry

so anyone playing around w/ LT1124ACN8? that chip sure sounds fantastic on my SHM-CD japanese remaster of "sex machine"...the drums are so clear, JB's voice so natural...it really is a nice chip 
	

	
	
		
		

		
		
	


	




 I understand the 4580/5532 are the way music is meant to be listened with...but well, studios use NS10M monitors...who would use these shoe boxes at home?


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Regarding the trim pins trick - we know nothing about the OPA228 and the AD797 schematic how it is done. For the LT1028 - I can agree it does not change the bias currents but decreases the input stage amplification a bit and increases the B-C junction headroom a bit. I also think that the change is a disputable improvement. For the OPA228 I like what I hear and I can make a quick comparison with an unmodded pair. So I'm sure of my impressions. The sound is more open and free of a slight nasal coloration which my friend also heard in my rig._

 

Do you know of any other tips,trick or mods for certain opamps?
 Appreciate any informaiton you might have.


----------



## qusp

leeperry, just wondering mate, with all this money you spend on these parts for your soundcard; could you not buy a set of headphones that allow you to hear the differences better?? also a source with even more potential?? I mean I totally get the whole tweaking business and spending more on tweaks than the product is worth (guilty of it myself), but headphones is another thing; I really enjoyed the CD3000; nearly bought some when a friend had them for sale, but they were hardly the last word in resolution, more fun sounding with quite good, but not fantastic detail, very nice bass texture and very musidcal. do the CD1000 have the same driver?? if its a lesser one, I dont get why you dont upgrade then; that would be sure to provide a bigger improvement than al this tweaking.

 now of course if you have found what you feel is your perfect headphone, thats fantastic!! carry on


----------



## diditmyself

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I understand the 4580/5532 are the way music is meant to be listened with...but well, studios use NS10M monitors...who would use these shoe boxes at home?_

 

It's not. They're cheap. It's just what manufacuters think is good enough in this price range. I think it's a scam when there are much better opamps only costing a couple of bucks more like LME49720.


----------



## majkel

@gusp - well said.

 @diditmyself - agreed. The best op-amps are not those most expensive but manufacturers cut costs wherever they can. NE5532 is much cheaper than the LME49720 and just slightly worse on paper. I prefer the LME49725 to the LME49720, BTW. Probably my favourite dual op-amp these days. 

 @leperry, compare the NJM4580 to the AD8022 or maybe LME49725, LM4562, whatever considered as decent, and hear what I mean saying "resolution". Looking for proper meaning of words makes no sense here. How is it possible that you hear more from circuits giving higher distortions? This is the HDAM case for instance.


----------



## majkel

double post


----------



## leeperry

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_I really enjoyed the CD3000; nearly bought some when a friend had them for sale, but they were hardly the last word in resolution, more fun sounding with quite good, but not fantastic detail, very nice bass texture and very musidcal. do the CD1000 have the same driver?? if its a lesser one, I dont get why you dont upgrade then; that would be sure to provide a bigger improvement than al this tweaking._

 

same drivers yes! and better sounding too as I've modded my cd1k quite a bit. I honestly don't think other cans under $1k would offer a wider SS...and I've tried a few of them too, many ppl who love the cd3k confirmed that you won't get a wider SS anywhere else...they even dare to say that it's on par w/ the R10: http://www.head-fi.org/forums/6163229-post49.html

 when majkel w/ his Grado toy says "well said", I LoL 
	

	
	
		
		

		
		
	


	




 I used to own a DT770/600Ω, very clear trebles...but very low PRAT and tiny SS.

 anyway, the Earth/LT1124ACN8 combo is fantastic...I'll stop rolling for a while, best of both worlds! the 1124 just has a very clear trebles/SS response I love(kudos to SpudHarris for the tip), and Earth gives a totally mind blowing 3D SS(you have to hear it to believe it in surround movies).
  Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_It's not. They're cheap. [..] there are much better opamps only costing a couple of bucks more like LME49720._

 

I really wouldn't call the 49720 "better" than the 4580. the 49720 makes me wanna jump off the window basically 
	

	
	
		
		

		
		
	


	




 As Andrea told me: _"the Accuphase DP-400 uses a bunch of NJM4580 (8 of them I think, but it has balanced outputs too) in its output stage and it's been taken as the magazine's reference in its price class since it was reviewed. 

 Recently they reviewed the Bryston DAC-1 (if that's how it's called) which has a very reassuring all-discrete output stage... Well they judged it extremely well, but they also said it was behind the DP-400 in terms of absolute transparency"_

 and sound engineers, Lynx soundcards and the Benchmark DAC1 use 5532 exclusively...should we give them a call and let me them know about their dumb choices?

 A friend of mine recorded all the Depeche Mode SACD in 24/96 5.1 w/ his Lynx Two-C, well...perfect SQ???
  Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_How is it possible that you hear more from circuits giving higher distortions? This is the HDAM case for instance._

 

yes yes, HDAM sound like ****...I'm filthy 
	

	
	
		
		

		
		
	


	




 no IC *whatsoever* will ever give you such a deep 3D-ish SS...if SS is not important to you is another matter altogether, considering you're using Grado's I'd fully understand that.


----------



## majkel

@leeperry, I didn't say the HDAM's sound bad. I just meant that circuits with low distortions not necessarily provide highly enjoyable sound with good resolution. I had occasion to listen a bit to the HD800, HD565, RS1, RS2 and PS1000 as well for the purpose of op-amp rolling. I also have never achieved better soundstage on any HDAM than that from the AD797BRZ pair. There is no op-amp chain in my setup, just one DAC output stage and then the headphone amp. For me, decompensated op-amps are in another league. OPA228, then LT1028, then AD8021. Things have changed a bit since I wrote the review and I sold all HDAMs. The first to go was the OPA-Moon, the most corrupting one, then OPA-Earth and finally the OPA un v.2 as it improves quite a bit and outperforms the OPA-Earth when the supply rails go up to 15V instead of 12V. I also noticed improvement when removed those crappy whitish Evox Rifa MMX caps from the HDAMs as I have better ones on board. I am sorry my impressions don't comply with popular revelations but I receive a PM from time to time from people who are to shy to admit I was right.


----------



## leeperry

point taken, the distortion graphs for the AD797 look indeed astonishing...I should get my AD797B early next week, very eager to try them as AK4396 LPF to feed Earth or as final buffer behind the 1124 
	

	
	
		
		

		
		
	


	




 well "better" is very subjective, the SS of Earth is 3D-ish to death(many ppl can confirm)...everything's well separated and breathing in its very own location, what I've heard so far from all the IC's I've tried(including the 1028ACN8) was mushy SS w/ everything mixed up...Earth doesn't do that.

 well, Moon is distorted to death(RMAA measurements concur what I'm hearing), and Sun-V2 is missing some tonal nuances as you said...very annoying.

 I'm not saying Earth is the best op-amp replacement in the world(as I still haven't received my new burson), but PRAT is up the roof and the SS is 3D-ish to death w/ everything nicely separated. I doubt the AD797BN will be able to do that.

 w/ music in foobar/KS, I'm basically getting a 270 degrees SS(bass comes from the back), in movies(using 5.1>binaural downmix matrixes) it's like 300 degrees...and in the barbershop demo it's clearly 360 degrees! OMG the trimmer at the back of the head is 
	

	
	
		
		

		
		
	


	




 I understand my cd1k has a HUGE SS on its own, and it matches w/ Earth amazingly well...maybe w/ some grado's(that are said to have a narrower "on-stage" SS), the difference wouldn't be so audible.

 what matters in the end is the end-user satisfaction(I like to be stunned on a permanent basis), and I've owned this cd1k for almost 15 years now...it's never sounded as good as it does w/ my current setup 
	

	
	
		
		

		
		
	


	




 sure, a Benchmark DAC1, an HD800 and a killer tube amp would prolly kill my current combo...I'm not questioning that, but I've always prefered the Japanese sound over german/US anyway(I'm not a basshead). these SONY high end headphones give exactly the sound I'm looking for, LT1124 just sounds very natural and clear and Earth is the icing on the cake


----------



## Vort3xxX

I ordered 2 AD797BR mounted on a 2xSOIC to 1 dip board on ebay this week. I want to upgrade my PCM2702E + BUF634 setup. I'm starting to question my purchase... all the reviews I see are for AD797BRZ. Does anybody know the difference between the BR & The BRZ?


----------



## leeperry

http://www.analog.com/static/importe...eets/AD797.pdf
  Quote:


 Z = RoHS Compliant Part.


----------



## diditmyself

Quote:


  Originally Posted by *Vort3xxX* /img/forum/go_quote.gif 
_I ordered 2 AD797BR mounted on a 2xSOIC to 1 dip board on ebay this week. I want to upgrade my PCM2702E + BUF634 setup. I'm starting to question my purchase... all the reviews I see are for AD797BRZ. Does anybody know the difference between the BR & The BRZ?_

 

The question is: do you believe in anacdotes, superstition and rumors or do you believe in common sense? IMO there's no reason to believe that different endings on opamps make them sound different. The circuit is the same. They come from the same production line, as far as I understand, and some opamps are picked and tested for tighter tolerance and get a higher "grading".

 Regarding BRZ, it means that they are lead-free. Some think that lead free devices sound worse.

 Be sure to implement it right. As a DAC filter/buffer I've found them to work well and sound good.


----------



## diditmyself

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_and sound engineers, Lynx soundcards and the Benchmark DAC1 use 5532 exclusively...should we give them a call and let me them know about their dumb choices?_

 

Now, that's a good idea, but it would take the edge of DIY. Why strive for improvements if NE5532 is perfect. I can see some points in using NE5532 if you find a DAC too aggressive, and you want a smoothing effect.

 When used in line stages etc, there's not only direct sound improvements when "newer and better" opamps are used. The bias currents are lower and you can often ditch coupling capacitors.


----------



## majkel

I have AD797ANZ and AD797BRZ for direct comparison, as well as LT1028CN8 and LT1028ACN8. They are all different, and higher spec series sound better. The same applies to the AD8620 ARZ and BRZ series. It's not true they are produced on the same production line. Even the packages differ and I don't mean the SOIC against DIP difference. OPA2228PA is slightly different than the OPA2228P and the OPA211ID is slightly different than the OPA211AID. Not as much as AD or LT chips and here it's disputable whether to invest more or not.


----------



## leeperry

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_Some think that lead free devices sound worse._

 

O RLY?! I know some ppl think that Sn63Pb37 solder is better than lead-free eutectic solder....but I highly doubt that 
	

	
	
		
		

		
			




  Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_When used in line stages etc, there's not only direct sound improvements when "newer and better" opamps are used. The bias currents are lower and you can often ditch coupling capacitors._

 

I think properly implemented 4580/5532 can sound *really* good, but the higher grade the chip the easier it is to make it sound good.

 in this thread we mostly play god at rolling op-amps and hoping for the best, but any EE will laugh at you if you discuss this sort of behavior I'm afraid.
  Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I have AD797ANZ and AD797BRZ for direct comparison, as well as LT1028CN8 and LT1028ACN8. They are all different, and higher spec series sound better._

 

compare an OPA2132P to an OPA2134P and it's not hard to hear the diff..the higher the grade the better it will sound w/o requiring circuit modification, it mostly makes the op-amp roller job easier I think. There's simply more headroom for poor design matching.


----------



## majkel

I'm an EE and I have abandoned parameter worship since I started building or modding audio circuits. You need measuring or calculating many parameters but... sometimes it's a 20% change and you hear nothing. The other time it's 0,0001% change and you hear it. Just because it is in range of audible decibles or out of range of your test equipment accuracy.


----------



## Vort3xxX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_Z = RoHS Compliant Part._

 

Well, I like my music with a modicum of danger, so this reassures me that I have made the best possible purchasing decision.


----------



## diditmyself

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I'm an EE and I have abandoned parameter worship since I started building or modding audio circuits. You need measuring or calculating many parameters but... sometimes it's a 20% change and you hear nothing. The other time it's 0,0001% change and you hear it. Just because it is in range of audible decibles or out of range of your test equipment accuracy._

 

I totally agree. Measurements doesn't tell how it sounds. I often do tweaks live like adding compensation caps, add local feedback, class A bias, reduce feedback etc. It's striking to find how little (most often absolutely nothing) those changes do to the sound while they're measurable. On the other hand, eg by changing transistors there's no measurable difference but quite audible. IMO it's the topology and the active parts that make the difference.

 One has to be aware of placebo effects, distorted sound memory and not listening at exactly the same level. If I do changes with the amp off and then listen, I often hear "the expected difference", but if I do it live or blind I hear no difference.


----------



## leeperry

I think the best way to avoid placebo w/ op-amps is to run them for a few days each time...so difference is clearly audible.

 BTW, I very much enjoy LT1124....would LT1126 be a good option? it's the same, just decompensated(_decompensated version of these devices, with three times higher slew rate and bandwidth_)..but apparently it's only an improvement at very high gains?

 I very much don't want to kill my card


----------



## 12Bass

Last night I had a musician friend of mine compare OPA211, AD797, and TL072 in the output stage of my Eden bass amplifier. It was interesting swapping the parts and have him guess which one was which. He could notice differences, but had a rather difficult time articulating what he was hearing and wasn't completely reliable in picking them out. I thought that the signatures of each were fairly audible - AD797 is a bit laid back, warm, and clean, OPA211 sounded more direct, with more sparkle, while TL072 sounded sort of veiled, warm, and furry..... Definitely prefer OPA211 in this application, although AD797 might be nice for a mellower tonality....


----------



## ROBSCIX

It is always interesting to compare other peoples opinions to your own especially in a subject that is well, so subjective.


----------



## SpudHarris

OPA177 Was recommended to me by TI. Does anyone have any knowledge of this chip??

EDIT: Scratch that, just noticed how much they cost. Jellybean at best......


----------



## opamp_addict

ON SEMICONDUCTOR - MC33078P 
 Anyone have knowledge on this chip? The Beyerdynamic A1 amplifier using those.


----------



## leeperry

so noone's got an idea on LT1126? I was told on diyaudio.com that using decompensated op-amps was a terrible idea, it'd only be useful on high gain designs.

 anyway, I've finally received my new burson+mundorf cap...time for a roll


----------



## leeperry

humm....I've seen this kind of comparison on a french forum and I like it 
	

	
	
		
		

		
		
	


	




 JRC4580 would be 0%, LM4562NA would be 33%, Earth would be 66% and the new burson(+mundorf cap) would be 100% 
	

	
	
		
		

		
		
	


	




 sound is more focused than Earth, less distant, more analog-like, less distorted, SS is even wider, vocals are more natural...I guess there's a reason why they're so pricey and yet still sell like hot cakes(I've listened to my favorite tracks on Earth for several hours before rolling the Burson).

 I could have used 2 sockets as risers, but then it was too tall to fit in my case...and at least cooling is optimal hummmm'kay(I've got a 25cm fan in the side door):



 

 

 it should be noted that this burson comes from Marko's STX and is fully burned in(+400H)...my Earth was only a few days old(and I didn't hear much diff tbh, I'm not really an op-amp burning in believer).


----------



## GWorlDofSPACE

leeperry!

 I would suggest you to put the burson opamp directly into the sound cards socket. Whit the extension adapter you can have more distortion.) Nice look. It would be interesting to compare it whit essence card! 

 Have fun whit it.


----------



## GWorlDofSPACE

leeperry!

 I would suggest you to put the burson opamp directly into the sound cards socket. Whit the extension adapter you can have more distortion.) Nice look. It would be interesting to compare it whit essence card! 

 Have fun whit it.


----------



## leeperry

well I could use 2 sockets as risers, but then the cap is too large to fit...I honestly don't get any major distortion(such as crackles or stuff like that), SQ is way better than on Earth indeed 
	

	
	
		
		

		
			





 and I'm quite sure your big *ss decoupling cap would kill any oscillation...lot of tiny details that were hidden(even on Earth) are now clearly audible.

 well, the STX sounds very agressive compared this HD2 Advance, by far the best SQ I've heard so far.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_OPA177 Was recommended to me by TI. Does anyone have any knowledge of this chip??

EDIT: Scratch that, just noticed how much they cost. Jellybean at best......_

 

Yes. I have some testing done with these units. They are the single channel version of the 2227 IIRC. I was using the 177 as a bass channel opamp and it worked great for that.
 The dual channel brothers, The 2227's have that typical laid back sound but they seem to have a really good bass, tight articulate..etc. I always recommend the 2227's to people who want more bass, or rather "better" bass or they need a opamps for a subwoofer channel.
 They are fairly cheap though but I wouldn't let that stop you from doing some tests.


----------



## SpudHarris

Thanks for the info Rob, yeah got a few 2227's as I used to put them in my cmoys I was selling on ebay a while ago. I still quite like that chip for what it costs.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Thanks for the info Rob, yeah got a few 2227's as I used to put them in my cmoys I was selling on ebay a while ago. I still quite like that chip for what it costs._

 

No problem. I always keep a few of the 2227 chip around for bass channels.
 I have also been working with the OPA177 as part of a larger amp unit for a project.

 TI recommended the OPA177 chip to you? -With what application in mind, just audio?


----------



## diditmyself

Now I've finally tried OPA827. It's by far the most neutral opamp I've tried. For the first time I don't have an urge to blend opamps (ground and L/R) to get the tonality I want. It's not only neutral in tonality but also very clean and have a good soundstage. Like most opamps it's a bit "slim". It might have to do with harmonics. I haven't measured it but I'd guess it's dominated by third harmonics and there's probably almost no second. I think this also makes the amp a bit on the spacious side of neutral.

 A funny thing is DC precision. For the first time I get a 0.0 mV DC-offset reading.


----------



## igor0203

Welcome to the OPA827 club


----------



## 12Bass

Yep... OPA827 is a great pick for eliminating DC offset and removing interstage coupling capacitors.


----------



## ROBSCIX

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_Welcome to the OPA827 club 
	

	
	
		
		

		
		
	


	


_

 

Yes, many around here like that opamp after testing. Not everybody though...


----------



## SpudHarris

I love the 827's but for my application (P3+) OMG, I have just found the ultra combination. OPA2111KP in L/R / Stacked BUF634's and OPA627's in Ground and VGround. I pinched this combo idea from one of the guys here on head-fi (Ryuzoh) he had it listed under his P3+ inventory so thought I'd give it a try and wow.......

 I am a big fan of Ryuzoh who is one of the guys behind some new amp projects with ibasso such as the Fi-Q. He is such a clever chap and always responsive to queries or questions, he has no doubt tested this combo in his P3+ and found it to be best for this curcuit. I have to say that this little amp holds up against my Graham Slee Solo PSU1 no bulls$&t.


----------



## ROBSCIX

Great stuff.
 I just got in some Bu634's for moding based on your suggestions.


----------



## SpudHarris

Not a big difference between stacked and Hi-C so from a cost point of view you are better off going Hi-C, 220ohm metal film resistor cost a lot less than a Buf634. In fact I think I prefer Hi-C as the stacked Buf's sound a little dark for me.


----------



## leeperry

anyone ever tried different op-amps for each polarity on browndog's used as DAC LPF? like one 1028ACN8 for + and one 1363CN8 for -

 please tell me it's not possible...this would open WAY too many possible combinations


----------



## igor0203

Try and report


----------



## leeperry

well, that should work...I'll wait for Andrea and/or majkel's feedback, they prolly already thought about/tried it 
	

	
	
		
		

		
		
	


	




 anyway, I just swapped LT1124ACN8 for LT1213ACN8.....humm, don't like it..major loss of definition here. I'll try LT1469IN8 again, this one is nice...but maybe not as nice as 1124 
	

	
	
		
		

		
		
	


	




 I could easily foresee that I'm gonna roll until the end of days...and put back the 1124 in the end


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Not a big difference between stacked and Hi-C so from a cost point of view you are better off going Hi-C, 220ohm metal film resistor cost a lot less than a Buf634. In fact I think I prefer Hi-C as the stacked Buf's sound a little dark for me._

 

Yes, I want to build some Hi-C Buf634s..what is this "stacked'?- pretty much what it sounds like?


----------



## diditmyself

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Yes, I want to build some Hi-C Buf634s..what is this "stacked'?- pretty much what it sounds like?_

 

If you want class A operation, why not build a discrete MOSFET or bipolar buffer?


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Yes, I want to build some Hi-C Buf634s..what is this "stacked'?- pretty much what it sounds like?_

 

Yep one on top of another with a tac of solder on the pins. Like I said though, I prefer Hi-C's. I'll post a pic in a while of the SOIC-DIP adapters with the option for resistor mods including pins 1-4 for Hi-C buffers.


----------



## SpudHarris

My new type of Hi-C buffers under construction. These look a lot nicer than using a DIP socket.


----------



## leeperry

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_Try and report _

 

well, Andrea advised against it, and so did another friend...I will ask a few EE friends, they'll think I'm nuts but no biggy ^^

 anyway, LT1469IN8 lacks the HD sound of LT1124(sounds like a cheap AM radio when fed to the Burson, when a LT1124ACN8 sounded like high-def hifi), I'm in for a rollback...tomorrow I'll swap for 4*LT1028ACN8, can't wait


----------



## qusp

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_If you want class A operation, why not build a discrete MOSFET or bipolar buffer?_

 

exactly!!


----------



## leeperry

Quote:


  Originally Posted by *GWorlDofSPACE* /img/forum/go_quote.gif 
_leeperry!

 I would suggest you to put the burson opamp directly into the sound cards socket. Whit the extension adapter you can have more distortion._

 

ok, I've rearranged my PC case and got rid of the dready extension leads...I still had to use two high-grade gold plated risers, though(as the red WIMA caps were getting in the way) 
	

	
	
		
		

		
		
	


	








 there seems to be less "zing" in the trebles indeed...your Mundorf cap doesn't seem to be soldered to the same pins as the Audio-GD parts, so its original goal might not be to kill oscillation 
	

	
	
		
		

		
		
	


	




 and LT1124ACN8 is still a fantastic chip! I'll roll back Earth(w/o extensions if it fits) later today, just to make sure I'm not imagining things...but the SS is just so clear/detailed and natural on the Burson+1124


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_My new type of Hi-C buffers under construction. These look a lot nicer than using a DIP socket.









_

 

Those are slick for adding caps and resistors.


----------



## ROBSCIX

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_If you want class A operation, why not build a discrete MOSFET or bipolar buffer?_

 

I am usually working on many projects at once and one of them is a discrete opamp. Do you have other suggestions for something to else to build?
 Do you have information for a Bipolar buffer?


----------



## ecclesand

Just finished switching my Lite DAC-AH to a passive output using some nice Auricaps. The improvement is quite noticeable. Needless to say, no more opamps for the Lite. That leaves me with my 2 small DAC/AMP combos that I tinker with for fun and with the ADA4627, I won't be rolling opamps in those anytime soon.

 Bah! Who am I kidding...I still need to try the modded opa228....


----------



## ROBSCIX

..so your giving up opamps for a passive out?
 New thread "Capacitor Rolling"?

 Modded 228, that is next on my list.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_..so your giving up opamps for a passive out?
 New thread "Capacitor Rolling"?_

 

No way. The Auricaps cost around $20 each shipped which is pretty reasonable. Some of the Mundorfs can run above $200 each!
	

	
	
		
		

		
		
	


	




 Maybe I'll start rolling resistors. I have some nice Vishay Wirewound resistors in there now. Nice and punchy. I tried some Riken Carbons but didn't care for them. This is why I was inquiring about resistor sockets a few days ago.


----------



## leeperry

Mundorfs sound goooood


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_Mundorfs sound goooood 
	

	
	
		
		

		
		
	


	


_

 

Compared to?


----------



## leeperry

all the rest? http://www.audiocircle.com/index.php?topic=54218.0
  Quote:


 After listening more to the "neutral" camp of caps like Mundorf Zn and Relcap RTX, the calling card of Mundorf silver/gold has to be the come-hither midrange that is colorful without being colored, full of rich textures, and just bristling with life and vividness. I may respect some other caps more, but I love the Mundorf silver/gold like family. 
 

ppl rave about them on every single forum, and the one I currently use on the burson is just amazing...buying used gear is great, you don't have to care for break-in


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_all the rest? My Capacitor comparisons: Mundorfs, VCap, Sonicap Platinum, Auricap, etc

 ppl rave about them on every single forum, and the one I currently use on the burson is just amazing...buying used gear is great, you don't have to care for break-in 
	

	
	
		
		

		
			



_

 

I read that a while ago. I have read many positive reviews about the Auricaps but I certainly wouldn't say they sound better than everything else based on these reviews or writeups. Buy hey...whatever floats your boat.


----------



## leeperry

.


----------



## leeperry

well, some ppl I trust on french forums also swear by them...and they indeed seem to have an edge technology-wise compared to most other manufacturers, just like Burson for op-amps...they sure make for a nice combo 
	

	
	
		
		

		
		
	


	




*PS:* jeeez, ditching the extension leads on the burson has definitely improved the SQ of the virtual barbershop demo...this one is just amazing, _"ahh it's so nice to see you"_ w/ his thick italian accent 
	

	
	
		
		

		
		
	


	




 and the demo w/ the matches in 360 degrees sounds so true to life, hah


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well, some ppl I trust on french forums also swear by them...and they indeed seem to have an edge technology-wise compared to most other manufacturers, just like Burson for op-amps...they sure make for a nice combo 
	

	
	
		
		

		
		
	


	


_

 


 10 different people will have 10 different opinions on caps. They carry more opinions then opamps, by far


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_No way. The Auricaps cost around $20 each shipped which is pretty reasonable. Some of the Mundorfs can run above $200 each!
	

	
	
		
		

		
		
	


	




 Maybe I'll start rolling resistors. I have some nice Vishay Wirewound resistors in there now. Nice and punchy. I tried some Riken Carbons but didn't care for them. This is why I was inquiring about resistor sockets a few days ago._

 

Yeah, it was more of a joke. I know some people get really bent out of shape over caps and burning them it and using these weird hard to find units....Man they get really crazeeee. Many subjects are based on opinion in audio but none I have come across seem more shrouded in opinions and biases then audio capacitors.
 If there actually was a "cap rolling" thread, I doubt it would last a day and the mods would shut it down from all the arguing and flaming going on.


----------



## Mad Max

You guys know where I can get AD743JN(Z)'s?


----------



## majkel

please delete


----------



## leeperry

hey majkel 
	

	
	
		
		

		
		
	


	



 running the OPA228P following your advice, it's good indeed : 



 when running 2*single instead of 1*dual as ±8.8V AK4396 LPF, I always have the feeling that both channels are not coherent anymore(whatever discrete/SOIC8 or DIP8)...it seems to kill the stereo image, it's dual mono but not stereo anymore...basically running two parallel audio images.

 but well I'll roll the LT1028ACN8 later to check whether I'm imagining things 
	

	
	
		
		

		
		
	


	




*PS:* yes, the same way LT1364 creates an holographic soundstage for vocals, running 2*singles as DAC LPF seems to kill the stereo coherence...I'll try 4*LT1363CN8 tomorrow, but next on the list today will be LT1630/LT1632.


----------



## ROBSCIX

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_You guys know where I can get AD743JN(Z)'s?_

 

Did you try Analog devices? Are these hard to find or?


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_hey majkel 
	

	
	
		
		

		
		
	


	



 running the OPA228P following your advice, it's good indeed 
 when running 2*single instead of 1*dual as ±8.8V AK4396 LPF, I always have the feeling that both channels are not coherent anymore(whatever discrete/SOIC8 or DIP8)...it seems to kill the stereo image, it's dual mono but not stereo anymore...basically running two parallel audio images.

 but well I'll roll the LT1028ACN8 later to check whether I'm imagining things 
	

	
	
		
		

		
		
	


	




*PS:* yes, the same way LT1364 creates an holographic soundstage for vocals, running 2*singles as DAC LPF seems to kill the stereo coherence...I'll try 4*LT1363CN8 tomorrow, but next on the list today will be LT1630/LT1632._

 

IIRC, Majkel recommended trying these with a modification.


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Did you try Analog devices? Are these hard to find or?_

 

I can't find them in the UK. I got mine a while back but Farnell no longer stock them.


----------



## Mad Max

AD told me they only have the 16-lead packages, none of the 8-lead. Meh.


----------



## SpudHarris

I wouldn't sweat it Mad Max, they aren't the best I've heard. If it's AD you want you should look at the ADA4627-1 Sweeeeeet!


----------



## leeperry

Quote:


  Originally Posted by *igor0203* /img/forum/go_quote.gif 
_After some tests, I found that OPA2107 is much better than LT1632. LT is much more "closed", muddy and with sloppy bass._

 

I didn't like OPA2107AP, I'll roll LT1632IN8 now...I only see AD797BN as a possible candidate to take LT1124ACN8's crown as AK4396 LPF..but ya never know


----------



## igor0203

Leepery, you use RCA interconnects to your amplifier? Which one you use?


----------



## igor0203

Leeperry, you use RCA interconnects to your amplifier? Which one you use?


----------



## leeperry

actually I've rolled LT1630IN8...I've never been too lucky with >30Mhz GBW, it doesn't seem to sound as good as LT1124ACN8...lacks the High-Res feeling.

 I use the onboard high gain JRC4580 headphones out, it sounds great when properly fed..better than the Corda Arrieta IMO 
	

	
	
		
		

		
			





 when I asked a friend if using different op-amps for the ± polarities of the same channel would be OK, he told me that the goal is to have op-amps with the most similar specs in that specific case...so using different parts was complete nonsense.

 stereo imaging is far more critical on headphones than on speakers, and I have the feeling that going 2*singles kills the timings(that are measured in ps) to go from the DAC to the final buffer...at least with a dual op-amp both channels are treated the exact same way as it's a VERY fast process, and crosstalk is not really an issue as each dual op-amp takes care of the two polarities of the same channel.

 OTOH, my final buffer does run in stereo mode so 2*singles(like the burson) are a better option...or maybe it's already adding too much delay, which becomes hard to bear once you add it on top of the DAC output "jitter"...anyway I'll put back the LT1124 and watch a bunch of movies now


----------



## majkel

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_IIRC, Majkel recommended trying these with a modification._

 

Yes, it improves them in terms of transparency but for the sake of knowing what the OPA228/2228 is you can plug them in and listen. It's good not to have any compensated op-amps in the signal chain as they "steal" the OPA228 advantages.


----------



## leeperry

whether the burson is compensated remains to be seen.

 and BTW, the audio-gd discrete op-amps appear to be pirate copies of the burson's...and a new burson is night and day w/ an earth, no doubt! I've A/B'ed them several times.

 when you want crappy cheap copies, China is always here to save the day 
	

	
	
		
		

		
		
	


	




 before making false assumptions Majkel, I'd suggest that you try a new burson w/ a Mundorfs cap...that's where the party's at 
	

	
	
		
		

		
		
	


	




*PS:* my headphones are also single ended, so delay adds up in the end maybe.


----------



## diditmyself

If the Earth is a pirate copy of Burson, how could it be night and day? Have Audiogd screwed up the circuit? They seem to know their stuff. I wonder if those nice Toshiba transistors that can be bought for peanuts from china are the real deal? What looks like high quality metal film resistors might be cheap carbon film in disguise, and what's inside those classy named capacitors found in all cheap amps and DACs from China noone knows.


----------



## leeperry

well, going A/B shows that Earth is distorted as hell, bass is flabby, SS is narrower and messy...basically the Burson+Mundorfs cap puts a lot less bloat between you and the music, it's very shocking tbh 
	

	
	
		
		

		
		
	


	




 burson look like a snake oil company because Audio-GD likes to tell anyone who wants to listen that they were simply selling Earth w/ a HUGE mark up...well, whatever Slash47 or I can confirm you that this is FAR from the truth(at least w/ their new chip).

 as Burson says it:
  Quote:


 The Audiogd opamps are counterfeits of our design. Unfortunately, many audiophiles fall for their lies because they are cheap and look “similar” to our opamps. However, like all things in life, it’s the stuff that our customers don’t see that makes a difference. Our opamps go through a very strict component selection, component matching and tuning process that ensures their quality and stability. They are covered by a life time of replacement warranty. Our opamps have near zero DC offset which is very important for music reproduction. Studios select our opamp for this very reason. Poorly built discrete opamps often have very high DC offset that can either damage the equipment immediately or over the long run. 
 

BUT, as Andrea said, Earth uses crappy Evox MMK caps(if they're not fake), I've got a nice Mundorfs...that will also help.

 anyway! LT1124ACN8 + Burson plays music exactly the way I want to hear it...both an electronics shop around my place, Andrea, Slash47 and burson advise to ditch sockets and solder directly to the PCB...I might very well get the 2*LT1124ACN8 + Burson soldered(w/ cardas eutectic), and call it a day 
	

	
	
		
		

		
		
	


	




 one of the legs of a 1124 was slightly bent and the left channel was popping and was softer than the right one...I had to bend it properly again to get proper stereo sound, sockets *DO* kill SQ 
	

	
	
		
		

		
		
	


	




 top quality sockets(full thick gold plating) cost $0.5 a pop if you buy 5000 pcs...manufacturers really go cheap on the wrong parts...the worst being Asus on their ST/STX, they're not even machined!


----------



## ecclesand

I haven't tried the Burson modules yet...and probably never will. However, I can tell you that the A-gd HDAMs are nothing special. I found several ICs that sound better to my ears than any of them.


----------



## ROBSCIX

@LeePerry, Wow the first time you have even tested the discretes and all the sudden your an expert?
 LOL! Give it up! You just started rolling opamps a few months ago!
 The Earth is distorted as Hell, last week it was the best thing since poptarts according to you...Give it up!


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Yes, it improves them in terms of transparency but for the sake of knowing what the OPA228/2228 is you can plug them in and listen. It's good not to have any compensated op-amps in the signal chain as they "steal" the OPA228 advantages._

 

Yes, I am familiar with the 2227 and 2228 just never heard of that mod, I will have to check it out when I get time.
 In your opinion and tests do you find the 2228 has a similar bass response as the 2227?

 I would ignore that troll, if he had half a clue he would be dangerous. Some people just cannot be helped.


----------



## majkel

The OPA2227 is dull, with smaller soundstage. The OPA2228 provides freedom to the music. 
	

	
	
		
		

		
		
	


	




 I guess the OPA2228 bass is more accurate, not that warm.


----------



## leeperry

I'm really not here to sell anything, I prolly wouldn't have tried their chips if I had not traded one for 2 Sun-V2 to someone on the forum...they're pricey, but man do they sound good 
	

	
	
		
		

		
		
	


	




 when they say on their website that their chip as a final buffer is like a video-projector lens...they're very much spot-on! many nice projectors are pointless because they don't have a low MTF distortion lens made of AR multi-coated real glass...plastic lenses look blurry, full of chromatic aberrations and purple fringing.

 We're in the era of dumbing things down, and it's nice to see that you can get top notch equipment for a (little) premium...now I'm off to roll some movies for good


----------



## Mad Max

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I wouldn't sweat it Mad Max, they aren't the best I've heard. If it's AD you want you should look at the ADA4627-1 Sweeeeeet!_

 

That's another one I would like to try. =]

 I've been listening through my Minibox-E+ with LT1363 and LT1357, and the 1357 is some groovy and funky stuff, but I've grown tired of its sound already, lol. I find myself going back to AD8610/8065 or AD744. I still need to try out 797s in that little amp, too, to see what that's all about. (But I've been procrastinating, lol.)


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_The OPA2227 is dull, with smaller soundstage. The OPA2228 provides freedom to the music. 
	

	
	
		
		

		
		
	


	




 I guess the OPA2228 bass is more accurate, not that warm._

 

Yes, I don't prefer the 2227 for their upper range but I find they can give out a great bass response in the right circuit. I only have a dual 228 module to test I guess that will give a similar signature as the OPA2228, possibly a bit better....more testing always more testing.
	

	
	
		
		

		
		
	


	




 Thx for the information.
 BTW, any opinon on differences if any between the OPA177 and the OPA277?


----------



## crapback

Weird, everything I read up until now had Burson using the original earth design. As for distortion, I have no idea what you are hearing leeperry. I'll have to look up the THD results I've seen people post for the audio-gd hdams again. IIRC, all the hdams produced more distortion than most IC opamps, but the levels were still far below audible. I have tried IC's that do have individual qualities as good as or better than the earth, but nothing that comes as close to doing everything so well.

 Now I'm going to have to test the DC offset of one of my earth's with the bypass caps both on and off. The switch from the evox caps to the k40y9 pio's that I did seemed to make quite an improvement. I also noticed a difference in my zero when I upgraded the bypass caps I had in it from petp to pio caps. I would hope a fatty mundorf that probably cost as much as an earth would clear up any DC issues. leeperry, how about you remove the mundorf and test that out for a while and let us know the difference? 
	

	
	
		
		

		
		
	


	




I'm not about to invest in some uber fancy caps for the level of gear I have but I would love to know how much of an improvement they make with just a discrete opamp. 

 I'm calling you a pain in my butt leeperry. 
	

	
	
		
		

		
		
	


	




 I read over hundreds of post to get all the information that convinced me to buy 5 hdams in the first place. Now you make me want to go back and look it all up again. Geez, you act like I spend way too much time listening to music and feeding my head-fi addiction. Oh wait.


----------



## leeperry

hehehe, rolliing op-amps is poison indeed 
	

	
	
		
		

		
		
	


	




 we all know that the op-amp design is flawed, the smartest design engineers avoid them like the plague, they're colored to death and a cheap way to amplify a signal...I like this guy: ZERODAC

 he takes the problems in hands and ditches them all for tubes 
	

	
	
		
		

		
		
	


	




 anyway, we'll never know about that burson/audio-gd mumbo jumbo, one copied the other, one made chips for the other(possibly w/ higher QA)...what matters to me is that I listened to the 3 A-GD parts, Moon was distorted to death as shown in these measurements: RightMark Audio Analyzer test: comparison

 Sun-V2 was lacking some tonal nuances, like something was missing...SS was amazing but the sound itself was kinda crippled, colored to death...majkel kinda agreed on this: http://www.head-fi.org/forums/f6/aud...-v-2-a-397691/

 it's hard to put your finger on it, but there *IS* something missing...Earth had a wide SS, very amazing separation as the SS depth and width were much wider than anything I had ever head w/ IC's(I use headphones known to have a HUGE SS..a bit like the K701 on that point I was told).

 SS was really amazing...but well, the *new* burson + mundorfs cap just kills it 
	

	
	
		
		

		
		
	


	




 SS is a lot more natural, sound is a lot less distorted, there's far less noise between you and the music...it's like a distortion-free LT1364 to me, vocals give that holographic feeling when it's fed w/ LT1124ACN8...I don't think this can be topped, but well I still got a few parts to try: OPA227P/AD797BN/LT1363CN8/LT1028ACN8/LT1632IN8/LT1211ACN8/LT1215ACN8(that's merely an obsession 
	

	
	
		
		

		
		
	


	




)

 the LT1124 never gave this sort of SQ through any other chip(whatever IC or discrete)...the mundorfs cap I have is cheap on ebay, like $10 for two of them...and no, I'm not going to desolder it to see if the SQ is crap w/o it


----------



## leeperry

and to the sceptics, the "burson MK2" in that PDF distortion thingie was the old model from what burson just told me...so indeed very similar to Earth 
	

	
	
		
		

		
			





 I've always liked to talk to manufacturers directly, Beyer was also very helpful to clear things up about the zillion different models of DT770...infos on the forum were pointless because most ppl said "DT770" when they actually owned a "Pro" model


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_stereo imaging is far more critical on headphones than on speakers, and I have the feeling that going 2*singles kills the timings(that are measured in ps) to go from the DAC to the final buffer...at least with a dual op-amp both channels are treated the exact same way as it's a VERY fast process, and crosstalk is not really an issue as each dual op-amp takes care of the two polarities of the same channel._

 

picoseconds! LOL!. You must have very good hearing. Do you know that a picosecond is a millionth of a microsecond?, i.e. a millionth of a millionth of a second. If you are worried about ps delays then you better be measuring all your PCB tracks and component leads down to the millimetre. if one track is longer then the signal will arrive a few ps later! I think that is the least plausible reason for the difference between 1 dual and 2 singles. Any jitter effects are going to be on the input (digital) side of the DAC. The "A" output is analogue audio.


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_we all know that the op-amp design is flawed,_

 

Do we? Yet you persist...

  Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_the smartest design engineers avoid them like the plague, they're colored to death and a cheap way to amplify a signal..._

 

Can you cite some facts to back that up? What about guys like Walt Jung? I think you will find the smartest engineers know to understand every component's virtues and limitations and use the right part for the right job.


----------



## K3cT

I'm testing 2x AD843JNZ in L, R and OPA627BP in G channels of my DIY amplifier. I'm still not sure whether it's better or not than those NOS "white-label" OPA637BPs but on first glance, the AD843 seems to have a clearer sound with more treble details while the OPA637 wins with its 3D-like soundstaging. More listening time is needed.

 Next in line would be Majkel's favorite, the venerable AD797BRZs.


----------



## SpudHarris

K3cT, that looks like a nice amp 
	

	
	
		
		

		
		
	


	




...... Mind me asking what it is based upon and is the second pot for bass?

 Also, do try the AD797,s they are superb and I find they make really nice ground chips also. In my set up (P3+) they add to the 3D effect quite a bit in Ground & VGround.


----------



## K3cT

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_K3cT, that looks like a nice amp 
	

	
	
		
		

		
		
	


	




...... Mind me asking what it is based upon and is the second pot for bass?

 Also, do try the AD797,s they are superb and I find they make really nice ground chips also. In my set up (P3+) they add to the 3D effect quite a bit in Ground & VGround._

 

The basic idea is from the A47 but with a lot of modifications. It employs a 3-channel active ground topology with class A biasing at buffer stage as well as a Jung multiloop. 

 The 2nd knob is for bass boost yes. Right now I'm using Soshin PIO caps for that but would like to try Mundorf Silver-in-Oil in the near future. 

 I'm building a dual-rail regulated PSU for this at the moment. I'm still undecided whether to go for 2 Sigma25s or Sigma22. I'll probably go for the latter though. 

 Thanks for the tips, I can't wait to try those AD797s but I need to solder them on a board first though.


----------



## igor0203

OPA228UA on browndogs in. So far so good. 
 I found that OPA827 is a bit more open with greater upper extension compared to OPA228. But OPA228 is (i have that feeling) more neutral and with nice bass response.


----------



## leeperry

hehe, it's funny how when ppl disagree w/ you on facts easy to check they call you a troll or a shill(it sucks that the most expensive chips sound the best, get over it 
	

	
	
		
		

		
		
	


	




)...hey majkel! with all the nonsense and dull assumptions on that thread of yours(like burson=moon hahaha, where did you pull this one from?), it's just highly laughable 
	

	
	
		
		

		
		
	


	



 does Kingwa bribe you to spread such bs? you see, it works both ways my friend.
  Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_ Any jitter effects are going to be on the input (digital) side of the DAC._

 

indeed, I asked an EE friend and he told me that jitter only matters in the digital domain...I dunno why OPA228P doesn't work for me, the SS sounds like desynchronized dual mono and the low end bass is rather tame...the reason must come from somewhere else(maybe it's just that majkel is not as much of a golden ear genius as he wants you to believe?)

 and yes, digital jitter is measured in ps and is very much audible...the worse it is, the more broken the stereo image is.
  Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_Can you cite some facts to back that up? What about guys like Walt Jung? I think you will find the smartest engineers know to understand every component's virtues and limitations and use the right part for the right job._

 

Well, I've read maaaaany discussions on diyaudio.com where guys said exactly what I just repeated...op-amps are flawed, and color sound to death. and that's what my experience(and many ppl here too) has shown, reason why many ppl roll until the end of days coz after a while they always get bored of the added color(LM4562 being the worst offender, who could stand this sound for a year??)

 and even that lampizator guy cannot stand op-amps and ditches them for tubes, but sure he's prolly clueless


----------



## majkel

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_hehe, it's funny how when ppl disagree w/ you on facts easy to check they call you a troll or a shill(it sucks that the most expensive chips sound the best, get over it 
	

	
	
		
		

		
		
	


	




)...hey majkel! with all the nonsense and dull assumptions on that thread of yours(like burson=moon hahaha, where did you pull this one from?)_

 

Samuel Groner "Opamp distortion", page 105. The graphs show otherwise but if he compared schematics and layouts - why not? Remove those crappy MMK from the OPA-Moon and listen again. 
  Quote:


 indeed, I asked an EE friend and he told me that jitter only matters in the digital domain... 
 

True but what's the point?
  Quote:


 I dunno why OPA228P doesn't work for me, the SS sounds like desynchronized dual mono...the reason must come from somewhere else(maybe it's just that majkel is not as much of a golden ear genius as he wants you to believe?) 
 

No, it's just you being a total noob in field of electronics. I repeated many times - this op-amp is decompensated and it oscillates in your circuit. The circuit probably doesn't fulfill its minimum gain requirements and has no external compensation, either, which is rare in DAC circuits being lowpass filters but happens from time to time.
  Quote:


 Well, I've read maaaaany discussions on diyaudio.com where guys said exactly what I just repeated...op-amps are flawed, and color sound to death. 
 

No, properly chosen and supplied op-amps is what majority of your recordings have been recorded and mixed with. They are just too transparent to hide the EMI crap from stupid (lots of them seen in DIY forums) or cheapish power supply units. Switch mode PSU are the worst here, you have one in your PC. 
  Quote:


 and that's what my experience(and many ppl here too) has shown, reason why many ppl roll until the end of days coz after a while they always get bored of the added color(LM4562 being the worst offender, who could stand this sound for a year??)

 and even that lampizator guy cannot stand op-amps and ditches them for tubes, but sure he's prolly clueless 
	

	
	
		
		

		
		
	


	



 

I could agree that all internally compensated op-amps are in the same low league. You have to remove all of them from your signal chain to hear it's true. I have no such in my setup so I can hear when they strangle my music.


----------



## leeperry

well, I didn't design the soundcard PCB indeed(otherwise I wouldn't be in here doing some blind op-amp swapping), and I guess I should indeed stay far away from decompensated op-amps, it hurts my brain to get desynchronized dual mono sound...I'll check if OPA227P is the same.

 if you compare page 104 and 108, I really don't see what could possibly make you think that the old burson(which has been benchmarked in that test) and Moon are identical...he says on page 107 that the old burson appears to be identical to Earth, that's not exactly breaking news..only a "total noob"(as you so kindly said) doesn't know that.

 but I'm very much willing to believe that the crappy caps on the A-GD parts are a major deal breaker...but getting Mundorfs in China prolly wouldn't be too easy(genuines at least 
	

	
	
		
		

		
		
	


	




)

 time to try 4*LT1363CN8 
	

	
	
		
		

		
		
	


	




*PS:* ok, unity gain stable is the key I guess..I'll still have to try 4*OPA227P then: http://focus.ti.com/docs/prod/folders/print/opa228.html


----------



## majkel

"This amplifier appears to be (both mechanically and electrically) identical to the Audio-gd OPA-Moon (see page 87), even though the available specifications are different. " This stands on page 107, marked 105. It doesn't mean they sound the same. I can't tell what improvement it would be to replace internal capacitors but the decoupling ones on the outside are spoiling the sound when you have whatever decent around your op amp socket supply.


----------



## leeperry

well, my dear friend, you are a victim of teh typo error.

 I got the latest version from http://www.sg-acoustics.ch/analogue_...distortion.pdf

 this is page 107: 



 as it says here: 



 and yes, earth and the old burson would appear to be very similar indeed.


----------



## majkel

Looks like swaying from one B/S to another. AFAIR the *old* Burson had the OPA-Earth circuit.


----------



## leeperry

hahaha, I catch you on your bs and you still ask for more? ok, don't bother..you're on my ignore list now, your inexpertise and lack of reading skills are of no use to me. 

 Say hi to Kingwa for me...me love you looong time


----------



## majkel

I think you should control your schizofrenic reactions better. I commented the text from the picture, not your post.


----------



## Slash47

You can't use not unity gain stable opamps on the HD2, the gain is too low. LT1028, AD797, OPA(2)228, OPA637 etc all don't work or oscillate. The only one's that're stable and I don't know if they're unity gain are AD8022 and AD8397.

 It's a voltage out DAC chip (AK4396) so the opamps have a gain of just 1 to supply current and make it single ended. The layout isn't designed to make a gain of 1 good enough for something like the LT1028 and it's never gonna work for uncompensated BB's


----------



## leeperry

well, you told me yesterday that AD797 was a good choice in PM : _"Although some chips in some apps, like the AD797, are just as good as its discrete counterpart. Only when you use 'em as a direct followup to the DAC though"_

 it should have read "but not on the HD2" then...ah 
	

	
	
		
		

		
		
	


	




 so 4*LT1028ACN8 will also be a waste of time then? I'll roll 4*LT1363CN8 in a moment, this should work


----------



## ROBSCIX

I would be surprised if he listened seeing how he wants to learn everything the hard way. Carful, you will go on ignore also!


----------



## majkel

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_so 4*LT1028ACN8 will also be a waste of time then?_

 

No, if the source impedance is made to be 500 ohms or more. Here you might be more lucky. 
	

	
	
		
		

		
		
	


	




 My friend used two OPA2228P in his HD2 with success, it sounded better than OPA2604 to him. For the output buffer he used AD8599. People in most cases place AD8022 or AD8599 there. Both create great combos with OPA2604's in the first stage. The OPA228 is different from the OPA637 because you can compensate it for gains as low as 2. The OPA637 will never work for noise gains lower than 5. AD797 is unity gain stable by default but you can decompensate it for higher gains.


----------



## leeperry

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_You can't use not unity gain stable opamps on the HD2_

 

from what I see LT1124ACN8 isn't either(A-VCL that is), and it sounds amazing..

 OPA228P and LT1126ACN8 are decompensated, that's a big no-no indeed.


----------



## ROBSCIX

@Majkel, I wouldn't even bother giving him anything useful. 
 He seems to slap away your hand when you offer it...
 Let him learn on his own.


----------



## Slash47

Well, all of those sound pretty bad on the HD2 to me, including the 2228. I'd just use 'm for I/V myself. But I don't like OPA2604 -> AD8022 either (AD8599 is much, much better to me), so let's all just disagree 
	

	
	
		
		

		
		
	


	




 And leeperry, what I said to you is both accurate (I didn't say 'some' included the HD2 anywhere), I 'shouldn't' anything and it's a private message; isn't it pretty bad etiquette to discuss that openly? Even though the subject is pretty, uhm, bland.

 Anybody here have a M3? I'm thinking of doing one with OPA827 or the new AD thingy and use it as a preamp and hp amp. Good idea?


----------



## leeperry

hehe ok, thing is I only care for the HD2 right now...well, most of the usual suspects in this thread are on my ignore list, we can speak freely...it's not like you gave me the pw to the pentagon firewall root account 
	

	
	
		
		

		
		
	


	




 I still rest my case that LT1124ACN8 doesn't appear to be unity gain stable(the PDF doesn't mention it) and it still sounds amazing..decompensated op-amps are another story altogether indeed.


----------



## ROBSCIX

Slash47, here you might want to follow up over here as they are dicussing your info:
The best sounding audio integrated opamps - Page 39 - diyAudio


----------



## majkel

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_@Majkel, I wouldn't even bother giving him anything useful. 
 He seems to slap away your hand when you offer it...
 Let him learn on his own._

 

It's just for the sake of people reading and curious of the answer. Modded CD1000 and a headphone out from an entry level "audiophile" sound card are disputably reliable components to evaluate op amp abilities. If the headphone driver is the NJM4580 then I understand his mental condition.


----------



## ROBSCIX

Yes, the 4580 would definately color the output further.
 I guess, some people think with a few months of reading other peoples opinions they suddenly have it all figured out.


----------



## NelsonVandal

THD has almost nothing to do with perceived sound quality. If it were so tube amps would totally be out of the question. When designing discrete amps a lower THD can be achieved by higher open loop gain and increased feedback. Does it make the amp sound any better, well I don't think so. Some tweaks like current mirrors as LTP load reduces the THD dramatically but make the amp sound worse. If local feedback is applied to a two stage opamp based amp (opamp + buffer), the distortion of the amp as a whole will increase but I don't think the amp will sound any different.

 Then there's the harmonic spectrum. Even order is claimed to sound more musical/natural to the ear and odd order gives a more "detailed" and "faster" sound. Higher order distortion is said to sound unnatural and harsh, especially 7th order. A typical modern opamp has almost no even order harmonics and is dominated by third harmonics. Most discrete amps are dominated by 2nd and have some 3d. What you like is a matter of taste. In blind tests it has been shown that some people prefer 2nd order while about just as many prefer 3d.

 There are other theories that try to explain why amps sound good or not. This is one of them Memory Distortion Philosophies

 I don't think you can judge amps from looking at their THD.


----------



## majkel

I confirmed that JRC4580 is even on the Advance DE PCB. I'd replace it at once with the AD8397 for instance, or AD8022 as I did in my CD player. The improvement was obvious. Watching landscapes and sunsets through a dirty window makes no sense IMHO.


----------



## ROBSCIX

Quote:


  Originally Posted by *NelsonVandal* /img/forum/go_quote.gif 
_THD has almost nothing to do with perceived sound quality. If it were so tube amps would totally be out of the question. When designing discrete amps a lower THD can be achieved by higher open loop gain and increased feedback. Does it make the amp sound any better, well I don't think so. Some tweaks like current mirrors as LTP load reduces the THD dramatically but make the amp sound worse. If local feedback is applied to a two stage opamp based amp (opamp + buffer), the distortion of the amp as a whole will increase but I don't think the amp will sound any different.

 Then there's the harmonic spectrum. Even order is claimed to sound more musical/natural to the ear and odd order gives a more "detailed" and "faster" sound. Higher order distortion is said to sound unnatural and harsh, especially 7th order. A typical modern opamp has almost no even order harmonics and is dominated by third harmonics. Most discrete amps are dominated by 2nd and have some 3d. What you like is a matter of taste. In blind tests it has been shown that some people prefer 2nd order while about just as many prefer 3d.

 There are other theories that try to explain why amps sound good or not. This is one of them Memory Distortion Philosophies

 I don't think you can judge amps from looking at their THD._

 

Who said you can judge opamps based on their THD values?


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I confirmed that JRC4580 is even on the Advance DE PCB. I'd replace it at once with the AD8397 for instance, or AD8022 as I did in my CD player. The improvement was obvious. Watching landscapes and sunsets through a dirty window makes no sense IMHO._

 

Yes, the are a generic units similar to the NE5532,JRC2114D..etc. Like the NE5532 they still seem to be part of many designers toolboxes and reference designs either because of cost or component familiarity.


----------



## K3cT

Are there any comparisons between OPA827 and OPA637? A quick research revealed that there is no definite consensus regarding this. 

 I've been cooking the AD843JNZ and it's a fine, fine op-amp. Midrange doesn't seem to be as luscious as the OPA637BP but it sounds very clear. I still need to spend more time with it to get a better picture.


----------



## Slash47

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Slash47, here you might want to follow up over here as they are dicussing your info:
The best sounding audio integrated opamps - Page 39 - diyAudio_

 

Thanks for the link, I appreciate it, but I can't promise I'll read it all 
	

	
	
		
		

		
			





 The only thing that I don't quite get is why Majkel has some different findings then me when it comes to SQ in circuits I'm familiar with from the pro-audio world, while he seems to know about as much on the subject as me (although I'll happily admit my posts are inaccurate at times, I speak in general terms too much I think). I don't get why the OPA228 is nice (it lacks resolution) and why LT1028ACN8 > AD797BRZ, tbh, it does not compute 
	

	
	
		
		

		
		
	


	




 And the Burson = Moon thing sounds VERY weird as well, but I never listened to the Moon properly. His (or your, depending on the reader and with my apologies about mixing up 2nd and 3rd person) don't make sense to me, for some reason. But then again, neither do some other findings (like using the OPA2107 for anything at all 
	

	
	
		
		

		
		
	


	




 ) by other members so it just goes to show it's all in your head. Most of it, at least.

 And leeperry: OK, you're right, I surrender about the unity gain thing. But I KNOW the LT1028 and AD797 don't sound like they should by a mile and they seem unstable. The AD8597/9 is actually better for the HD2. And you have two LT1364, right? 2x LT1364 -> Burson is about as good as it gets on the stock card.


----------



## Slash47

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Are there any comparisons between OPA827 and OPA637? A quick research revealed that there is no definite consensus regarding this. 

 I've been cooking the AD843JNZ and it's a fine, fine op-amp. Midrange doesn't seem to be as luscious as the OPA637BP but it sounds very clear. I still need to spend more time with it to get a better picture._

 

I'm curious about this as well for my future M3. Buying both is quite pricey!


----------



## leeperry

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_leeperry: OK, you're right, I surrender about the unity gain thing. But I KNOW the LT1028 and AD797 don't sound like they should by a mile and they seem unstable. The AD8597/9 is actually better for the HD2. And you have two LT1364, right? 2x LT1364 -> Burson is about as good as it gets on the stock card._

 

ah, for once I'm right?! did I win something? ..or are you just pulling my leg? 
	

	
	
		
		

		
		
	


	




 yes I looooooved LT1364 on the OPA2132P, it was breathtaking..it's like you were in the studio cabin right next to the singer, totally amazing...but the SS was somehow unrefined.

 through Earth, it was distorted as hell..pointless.

 I'll roll 4*LT1363CN8 in a bit, and then 2*LT1364..why not 
	

	
	
		
		

		
		
	


	




 ah well, I wanna hear what the AD797BN/LT1028ACN8 fuss is all about...just to make sure I'm not missing something HUGE 
	

	
	
		
		

		
		
	


	



 and if you could please answer my last question, I sure as hell would appreciate it. 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *NelsonVandal* /img/forum/go_quote.gif 
_THD has almost nothing to do with perceived sound quality._

 

thanks for this long overdue reality check!


----------



## majkel

Slash47, for me the OPA2107 is too bad to be used in audio circuits at any supply voltage it can stand. It's just lifless, thin and boring. No impact, just dark and spatial sound. 

 The OPA228 fits best my DAC, then it's LT1028ACN8 and then AD797BRZ. I have a better headphone amp than in the time of the Audio-gd stuff review so the order has changed. The DAC has improved a bit as well. 

 If you read what NelsonVandal linked here, there is a statement that the NFB is great but only when the loop back is fast. The higher the compensation, the higher dependency of the feedback response time from the frequency. In decompensated op-amps you have much smaller phase shift for the signal fed back. OPA637 should be equally good but... its JFET inputs screw up things as... all JFET inputs do. 
	

	
	
		
		

		
		
	


	




 I don't know why but only OPA2604 sounds natural to me between JFET input op amps. OPA827 is like improved OPA627 but its cheaper probably due to lack of external offset trim pins.


----------



## 12Bass

Haven't measured any significant DC offset from OPA827 in my applications.... while THS4052 had more than others.


----------



## majkel

The trimming is for people who care about each uV. In audio... we don't.


----------



## 12Bass

My meter only measures mV, but would hover around +/- 0.0 mV when measuring DC offset on OPA827. Not sure how it compares with OPA627/637, as I have neither. It does sound good to me, but I have preferred OPA211 in some circuits.


----------



## leeperry

humm, this thread is useless w/o pics: 



 I had to put a string on the burson, as it's like a big resinous bud ya know...it'll remain like this until I get it soldered directly onto the PCB.

 anyways, SS is wider on the 1363 than your usual dual op-amps...but it doesn't feel uneasy like the 4*OPA228P did, there's still very much stereo coherence. SQ appears higher than 2*LT1124ACN8, will need more time to evaluate 
	

	
	
		
		

		
		
	


	




*PS:* ahhhh, the 1363/4 sure sound holographic on vocals


----------



## ecclesand

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_humm, this thread is useless w/o pics: 



 I had to put a string on the burson, as it's like a big resinous bud ya know...it'll remain like this until I get it soldered directly onto the PCB.

 anyways, SS is wider than your usual dual op-amps...but it doesn't feel uneasy like the 4*OPA228P did, there's still very much stereo coherence.

 SQ appears higher than 2*LT1124ACN8, will need more time to evaluate 
	

	
	
		
		

		
		
	


	


_

 

I think we get it...you LUUUVVVVVV your Burson!


----------



## leeperry

.


----------



## leeperry

haha, I'm just talking about the 1363 here...and all that dull chitchat needs some pics from time time to breeze things up, post some too if you dare 
	

	
	
		
		

		
		
	


	




 everyone said 1363 was a major improvement over 1364...it might very well be the case


----------



## ROBSCIX

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_Thanks for the link, I appreciate it, but I can't promise I'll read it all 
	

	
	
		
		

		
		
	


	


_

 

Just read the last few pages, You gave Leeperry some information he ran over there and ask what other what they thought?
  Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_The only thing that I don't quite get is why Majkel has some different findings then me when it comes to SQ in circuits I'm familiar with from the pro-audio world, while he seems to know about as much on the subject as me (although I'll happily admit my posts are inaccurate at times, I speak in general terms too much I think). I don't get why the OPA228 is nice (it lacks resolution) and why LT1028ACN8 > AD797BRZ, tbh, it does not compute 
	

	
	
		
		

		
		
	


	




 And the Burson = Moon thing sounds VERY weird as well, but I never listened to the Moon properly. His (or your, depending on the reader and with my apologies about mixing up 2nd and 3rd person) don't make sense to me, for some reason. But then again, neither do some other findings (like using the OPA2107 for anything at all 
	

	
	
		
		

		
		
	


	




 ) by other members so it just goes to show it's all in your head. Most of it, at least._

 

Many in this thread have extensive background in electronics. If your opinion varies, doesn't mean they are wrong or your are right. Audio, especially opamps is very subjective. If you like something great BUT that does not mean other will or they are wrong for not liking it. I know many people that like and use the OPA2107 for audio...Personally I think there are better opamps. I know other that like opamps I find boring or bland and would never use.
 Add that to the fact that most are using varied circuits, speakers or phones and it gets even more difficult to relay information. It is all just opinion...
 I never commented on the Moon but I do know it can become unstable when used in some circuits because I have seen it happen.
  Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_And leeperry: OK, you're right, I surrender about the unity gain thing. But I KNOW the LT1028 and AD797 don't sound like they should by a mile and they seem unstable. The AD8597/9 is actually better for the HD2. And you have two LT1364, right? 2x LT1364 -> Burson is about as good as it gets on the stock card._

 

Well again, that is a subjective personal opinion. In this hobby there is nothing beyond specs that can be considered hard facts. 
 I find this thread great because it can help people that are looking for new opamps but can only help them so much as they need to do the testing themselves.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I think we get it...you LUUUVVVVVV your Burson!
	

	
	
		
		

		
		
	


	


_

 

....and has posted he loves every other opamp he has tried.




 Those burson with the caps belonged to another member here but he sold them off. Marko I think is his name. 
 He used 3 on his STX. Marko added the caps...


----------



## ROBSCIX

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_ah,thanks for this long overdue reality check!_

 

IIRC, your the only person in this thread that was going overboard worrying about THD values. Most of use have been doing this much longer then you and know better.


----------



## leeperry

wow 3 messages in a row? someone should really try this 
	

	
	
		
		

		
			





 button instead of freeposting like there's no tomorrow 
	

	
	
		
		

		
		
	


	




 anyway, yeah...strings sound amazing on LT1363, and so do vocals...it was long time favorite of Andrea, I can hear why


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_The trimming is for people who care about each uV. In audio... we don't._

 

Majkel, have you tested out the LT1028's? What is your opinion on them?
 The post man dropped me off a a bunch of new components today.
 Amongst the part were some new opamps. I am testing them right now as a buffer and so far they are not too bad.


----------



## K3cT

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_I'm curious about this as well for my future M3. Buying both is quite pricey!_

 

Let's just say that the combo of 637BP at L,R and 627BP at G channels in my DIY amp is nothing short of amazing. It's liquid, detailed, musical complete with decent imaging and a very 3D-like soundstage. It just lacks snap and attack for certain genres of music.


----------



## ROBSCIX

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Let's just say that the combo of 637BP at L,R and 627BP at G channels in my DIY amp is nothing short of amazing. It's liquid, detailed, musical complete with decent imaging and a very 3D-like soundstage. It just lacks snap and attack for certain genres of music._

 

I like the 627 and 637's also but have never tried the BP varient.


----------



## Slash47

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Just read the last few pages, You gave Leeperry some information he ran over there and ask what other what they thought?

 Many in this thread have extensive background in electronics. If your opinion varies, doesn't mean they are wrong or your are right. Audio, especially opamps is very subjective. If you like something great BUT that does not mean other will or they are wrong for not liking it. I know many people that like and use the OPA2107 for audio...Personally I think there are better opamps. I know other that like opamps I find boring or bland and would never use.
 Add that to the fact that most are using varied circuits, speakers or phones and it gets even more difficult to relay information. It is all just opinion...
 I never commented on the Moon but I do know it can become unstable when used in some circuits because I have seen it happen.

 Well again, that is a subjective personal opinion. In this hobby there is nothing beyond specs that can be considered hard facts. 
 I find this thread great because it can help people that are looking for new opamps but can only help them so much as they need to do the testing themselves._

 

Yes, I agree 100% with this. I just have a tendency of thinking 'What, am I THAT much of an idiot' 
	

	
	
		
		

		
		
	


	




 And if someone discusses pm's openly that's completely wrong, no matter the subject.


----------



## leeperry

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_I just have a tendency of thinking 'What, am I THAT much of an idiot' 
	

	
	
		
		

		
		
	


	


_

 

you're OK, no worries...I've seen much worse lately 
	

	
	
		
		

		
		
	


	



  Quote:


 if someone discusses pm's openly that's completely wrong, no matter the subject. 
 






 who cares what these ppl think anyway? that's an interwebb board w/ a bunch of nerds who like to chitchat about $0.3 IC's..big deal 
	

	
	
		
		

		
		
	


	




 and I never came here to get confirmation about what you told me, that is false information..but the OP is also very imaginative, always trying to turn discussions into his own interest 
	

	
	
		
		

		
		
	


	




 anyway, case closed! LT1363CN8 is great, it will stay there for a while


----------



## Slash47

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Slash47, for me the OPA2107 is too bad to be used in audio circuits at any supply voltage it can stand. It's just lifless, thin and boring. No impact, just dark and spatial sound. 

 The OPA228 fits best my DAC, then it's LT1028ACN8 and then AD797BRZ. I have a better headphone amp than in the time of the Audio-gd stuff review so the order has changed. The DAC has improved a bit as well. 

 If you read what NelsonVandal linked here, there is a statement that the NFB is great but only when the loop back is fast. The higher the compensation, the higher dependency of the feedback response time from the frequency. In decompensated op-amps you have much smaller phase shift for the signal fed back. OPA637 should be equally good but... its JFET inputs screw up things as... all JFET inputs do. 
	

	
	
		
		

		
		
	


	




 I don't know why but only OPA2604 sounds natural to me between JFET input op amps. OPA827 is like improved OPA627 but its cheaper probably due to lack of external offset trim pins._

 

Hey, thanks for the input on the OPA827.

 I agree with you about the OPA604. It's funny, because I find it quite fuzzy at times, like listening to AM radio almost (very mildly, of course). Still, other do indeed just annoy me more which is actually strange looking at the numbers. I also like the AD8065 though. And in a design like a lot of headphone amps use (pot -> gain -> buffer) the OPA6x7 comes into it's own a lot more.

 And the OPA2107 remark was a stupid joke towards ROBSCIX, but I agree that it is _bad_. Some chips shouldn't exist 
	

	
	
		
		

		
		
	


	




 Regarding the DAC, I was messing with a studio DAC the other night which uses the same D/A chips as your DAC. I found the LT1028A less analogue then the AD797B. It just lacks the sophistication and presence. It might very well be that a couple of different values shift the balance, of course, but I found it quite a large difference so I wondered.


----------



## ROBSCIX

.double post


----------



## ROBSCIX

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_Hey, thanks for the input on the OPA827.

 I agree with you about the OPA604. It's funny, because I find it quite fuzzy at times, like listening to AM radio almost (very mildly, of course). Still, other do indeed just annoy me more which is actually strange looking at the numbers. I also like the AD8065 though. And in a design like a lot of headphone amps use (pot -> gain -> buffer) the OPA6x7 comes into it's own a lot more.

 And the OPA2107 remark was a stupid joke towards ROBSCIX, but I agree that it is bad. Some chips shouldn't exist 
	

	
	
		
		

		
		
	


	




 Regarding the DAC, I was messing with a studio DAC the other night which uses the same D/A chips as your DAC. I found the LT1028A less analogue then the AD797B. It just lacks the sophistication and presence. It might very well be that a couple of different values shift the balance, of course, but I found it quite a large difference so I wondered._

 

LOL, Yes, I caught the jab as I am aware of your opinions on the OPA2107 we discussed it before.
 What are your thoughts on the OPA827?
 I just got a set of LT1028A today so I cannot commment on them personally. I do like the AD797 though...


----------



## Slash47

I haven't tried it yet. I _have_ tried the OPA6x7's a lot, so I'm curious on opinions about how they compare


----------



## SpudHarris

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Let's just say that the combo of 637BP at L,R and 627BP at G channels in my DIY amp is nothing short of amazing. It's liquid, detailed, musical complete with decent imaging and a very 3D-like soundstage. It just lacks snap and attack for certain genres of music._

 

I've loved that combo for ever in my PPAv2 veeeery nice indeed. 

 Reference your earlier question about the 637's and 827's, I have always liked the 637's but have been limited where I could use them as my favourite portable (P3+) didn't like them one bit. I got real bugged out at one point because I thought the 637BP's were the holy grail and couldn't use them in the P3+. It was suggested that there are better sounding opamps and I personally agree with this now. I think that the OPA637's are bettered by both OPA827's and AD4627-1's in my application at least. It's all subjective but I also think that the AD797's are absolutely beautiful opamps.

 Source, bitrates, phones, cables, application and, and, and, and...... will all make a difference or yeld different opinions.


----------



## m1abrams

Question regarding why I do not see many people using the "BP" grade opamps over the "AP" grade?

 Example the OPA637BP has have the Input Bias Current and 6db higher CMRR over the OPA637AP. Is it just due to the fact that those gains are really not going to yield much in the audio application for the extra cost of the BP grade. On mouser the BP is $8 more per chip than the AP.


----------



## SpudHarris

I ordered some (4) Buf634's from TI and received something completely different by mistake. Does antone know what ISO1050 chips are? They are also marked up TI Z774 & 9AHG4, I've searched around but can't find anything.......Just curious is all. Anyone wants them they are free!!


----------



## majkel

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_Regarding the DAC, I was messing with a studio DAC the other night which uses the same D/A chips as your DAC. I found the LT1028A less analogue then the AD797B. It just lacks the sophistication and presence. It might very well be that a couple of different values shift the balance, of course, but I found it quite a large difference so I wondered._

 

Probably the output of the DAC provides low impedance at which the AD797 should excel. This is a one stage (folded cascode) op-amp, so it has high input currents. The LT1028 is 2 or 3 stage AFAIR, and it draws much lower currents which fits my DAC better as there are some 10k coupling resistors in between. 
 Also, the LT1028 is not unity gain stable at low source impedance but here it's not the case. Looking at the extrapolated THD graphs, the LT1028 should have lower distortions and it's faster than the AD797. FYI, when your circuit allows it, you can obtain better sonic results with AD8021 which is also decompensated but you can make it unity gain stable without using capacitors. And then it sounds even better, more transparent than the AD797. However, it doesn't work in my DAC and is not suited for it due to a number of magnitude larger input currents than the AD797. I tested the AD8021 against the AD797 in one of my amps in the active ground circuit.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I ordered some (4) Buf634's from TI and received something completely different by mistake. Does antone know what ISO1050 chips are? They are also marked up TI Z774 & 9AHG4, I've searched around but can't find anything.......Just curious is all. Anyone wants them they are free!!_

 

Never heard of them. Did you ask TI what they sent you?


----------



## LuciferX

I have 4xOPA2132P in my claro halo (Defaults are 4580). Now i have more Bass, less harsh highs, i like what im listening! The voice has more .... "body" ?. But in some tracks the bass is out of control.

 My 2107 samples has arrived, im thinking in 2x2107 an 2xOpa2132 as final buffers. How is 2107 in therms of highs, mids, lows? What do you people think about my combination? 



 PD: Im from Argentina, the only samples that comes here are from TI or National, LT never want to send me anything 
	

	
	
		
		

		
			





 exclude them if you want to give me recommendations


----------



## Slash47

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Probably the output of the DAC provides low impedance at which the AD797 should excel. This is a one stage (folded cascode) op-amp, so it has high input currents. The LT1028 is 2 or 3 stage AFAIR, and it draws much lower currents which fits my DAC better as there are some 10k coupling resistors in between. 
 Also, the LT1028 is not unity gain stable at low source impedance but here it's not the case. Looking at the extrapolated THD graphs, the LT1028 should have lower distortions and it's faster than the AD797. FYI, when your circuit allows it, you can obtain better sonic results with AD8021 which is also decompensated but you can make it unity gain stable without using capacitors. And then it sounds even better, more transparent than the AD797. However, it doesn't work in my DAC and is not suited for it due to a number of magnitude larger input currents than the AD797. I tested the AD8021 against the AD797 in one of my amps in the active ground circuit._

 

Isn't all that impedance bad for your SQ? 10k in coupling resistors sounds a bit high and creates more noise then the opamp itself 
	

	
	
		
		

		
		
	


	




 (Not trying to rip on your rig, just curious.) It does explain why different opamps sound better in your system, of course. AD797 would lose it's benefits. I believe in the DAC I had (custom one) the opamp had 800 and then 200Ohm in front of it. 

 Never tried the AD8021, just the AD8022. I'm having a hard time imagining why it'd sound better, but I'll try sometime.


----------



## Slash47

Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_I have 4xOPA2132P in my claro halo (Defaults are 4580). Now i have more Bass, less harsh highs, i like what im listening! The voice has more .... "body" ?. But in some tracks the bass is out of control.

 My 2107 samples has arrived, im thinking in 2x2107 an 2xOpa2132 as final buffers. How is 2107 in therms of highs, mids, lows? What do you people think about my combination? 



 PD: Im from Argentina, the only samples that comes here are from TI or National, LT never want to send me anything 
	

	
	
		
		

		
		
	


	




 exclude them if you want to give me recommendations_

 

Get some LM6172's from National. They should be great on your soundcard, nice and mellow with tight bass. They're very unique in their sound but worth a try. OPA2107 is more spacious then the 2132 but has less body and depth. Might be a nice mix, but only you'll be able to say for sure! Be sure to try both OPA2132 -> 2107 _and_ 2107 -> 2132, it'll be different.


----------



## LuciferX

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_Get some LM6172's from National. They should be great on your soundcard, nice and mellow with tight bass. They're very unique in their sound but worth a try. OPA2107 is more spacious then the 2132 but has less body and depth. Might be a nice mix, but only you'll be able to say for sure! Be sure to try both OPA2132 -> 2107 and 2107 -> 2132, it'll be different._

 

They didnt have DIP samples 
	

	
	
		
		

		
		
	


	




 I should try LM6172 x 2 + 2 x OPA2132 or all LM ?


----------



## Slash47

Quote:


  Originally Posted by *LuciferX* /img/forum/go_quote.gif 
_They didnt have DIP samples 
	

	
	
		
		

		
		
	


	




 I should try LM6172 x 2 + 2 x OPA2132 or all LM ?_

 

I think you can get 5 samples from National. I doubt they'd have synergy with OPA2132, but you never know.

 You could also get some LM4562 for free, which are a very solid upgrade over the JRC's. Way more detail. Ask others as well though. I don't know of any other good chips you can sample. You can get OPA2604, but I wouldn't use four of those. Maybe two in combination with something else, but I wouldn't know which ones. For the really nice ones you need to bust out the soldering iron and a creditcard


----------



## LuciferX

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_I think you can get 5 samples from National. I doubt they'd have synergy with OPA2132, but you never know.

 You could also get some LM4562 for free, which are a very solid upgrade over the JRC's. Way more detail. Ask others as well though. I don't know of any other good chips you can sample. You can get OPA2604, but I wouldn't use four of those. Maybe two in combination with something else, but I wouldn't know which ones. For the really nice ones you need to bust out the soldering iron and a creditcard 
	

	
	
		
		

		
		
	


	


_

 

I have LM4562NA, LME49860NA and LME49720NA here, not tested yet, all says me "all are the same" ... they dont have a lot of bass right? may be in combo with OPA2132P .... What do you think?


----------



## Slash47

You could try 2x OPA2132 -> LM4xxxx.

 But why not just try 'm yourself?


----------



## LuciferX

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_You could try 2x OPA2132 -> LM4xxxx.

 But why not just try 'm yourself?_

 

I think to much, and put the sound card out of my case is a pain in the **** so ... always ask for advice and experiences  (this will be my second time rolling opamps). Always i want to know what to expect of a particular Opamp

 EDIT: LM as buffer? Always think that the more "analytical" part goes first


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Never heard of them. Did you ask TI what they sent you?_

 

I contacted customer service and they phoned my home (UK) to apologise and to let me know the replacements were being sent. TI's service is something special........


----------



## majkel

Quote:


  Originally Posted by *Slash47* /img/forum/go_quote.gif 
_Isn't all that impedance bad for your SQ? 10k in coupling resistors sounds a bit high and creates more noise then the opamp itself 
	

	
	
		
		

		
		
	


	


_

 

They are high but due to highpass filtering, they allow smaller signal capacitors in series. But you're right. It's much about proper source impedance. However, op amps suited for high source impedance don't fit, either.  Quote:


 (Not trying to rip on your rig, just curious.) It does explain why different opamps sound better in your system, of course. AD797 would lose it's benefits. I believe in the DAC I had (custom one) the opamp had 800 and then 200Ohm in front of it. 
 

Well, you can say it loses as it works a bit above optimal source impedance. On the other hand, it performed better than JFET input HDAMs I had and in some configurations was the best. These are all slight differences between LT1028 and AD797, just a bit lower was the OPA211 and above all the OPA228. When I have time, I will try a discrete output stage with no feedback loop and see. The problem is it must be AC coupled. 
  Quote:


 Never tried the AD8021, just the AD8022. I'm having a hard time imagining why it'd sound better, but I'll try sometime. 
 

AD8021 is much faster with higher bandwidth and shorter settling time than the AD797. This means its distortions start to increase at higher frequency and you can assume the curve is flat for the usable audio range. BTW, AD8022 is not dual AD8021.


----------



## RAFA

HI

 What is the best opamp in combination with an Ultrasone Pro 900?


----------



## majkel

Where are you going to use this op amp?


----------



## ROBSCIX

Quote:


  Originally Posted by *RAFA* /img/forum/go_quote.gif 
_HI

 What is the best opamp in combination with an Ultrasone Pro 900?_

 

What are you going to use this opamp in?


----------



## RAFA

I would like to make Cmoy first and then shortly after that a maybe more sophisticated portable amp or buy one and do opamp rolling.

 However, I do not expect the Cmoy to sound perfect, but I believe that an amp and a headphone must match, even if it is just the part of an codec.


----------



## majkel

AD8397 and see the Tangent's remarks on how to minimize the offset by proper resistor values selection.


----------



## RAFA

thank you, I willtry it definitely try it.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Many in this thread have extensive background in electronics. If your opinion varies, doesn't mean they are wrong or your are right. Audio, especially opamps is very subjective._

 

I'll admit, I have little to no background in electronics. In fact, what I do know makes me dangerous. I have read datasheets for opamps and still struggle to understand what make one better over another when looking at bandwidth and slew rates. I'm good with a soldering iron and I know basic electronics if I have a schematic, but anything beyond that...I'm completely lost. So, for rolling opamps, I simply stick one in and see if I like it. If I do and it doesn't catch fire or oscillate like a mutha, then I leave it in.


----------



## SpudHarris

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I'll admit, I have little to no background in electronics. In fact, what I do know makes me dangerous. I have read datasheets for opamps and still struggle to understand what make one better over another when looking at bandwidth and slew rates. I'm good with a soldering iron and I know basic electronics if I have a schematic, but anything beyond that...I'm completely lost. So, for rolling opamps, I simply stick one in and see if I like it. If I do and it doesn't catch fire or oscillate like a mutha, then I leave it in.
	

	
	
		
		

		
		
	


	


_

 

That's brilliant Doug, that's me to a tee


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_That's brilliant Doug, that's me to a tee 
	

	
	
		
		

		
		
	


	


_

 

Team KnowsJustEnoughAboutElectronicsToBeDangerous FTW!
	

	
	
		
		

		
		
	


	




 I wonder if there is an Electronics for Dummies book available. I need to get one. You would have laughed had you seen how I screwed up the passive output on my Lite the first go around. I worked on it until 4am but did eventually get it working! I even tried to revert back to the active output with the opamps and found that I had screwed something up on that too. I did buy another used Lite as a backup so I can still try opamps and compare the 2.

 YES!
http://www.amazon.com/s/ref=nb_ss_0_...ectronics+for+


----------



## SpudHarris

Haha, yeah think I'll put that my Crimbo list for sure......


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I'll admit, I have little to no background in electronics. In fact, what I do know makes me dangerous. I have read datasheets for opamps and still struggle to understand what make one better over another when looking at bandwidth and slew rates. I'm good with a soldering iron and I know basic electronics if I have a schematic, but anything beyond that...I'm completely lost. So, for rolling opamps, I simply stick one in and see if I like it. If I do and it doesn't catch fire or oscillate like a mutha, then I leave it in.
	

	
	
		
		

		
		
	


	


_

 

Well it makes you smarter then some others as alteast you know that you don't know.


----------



## diditmyself

Nah, books are boring. I think it's a lot easier to understand things by doing. You should learn LTSpice so you don't have to make mistakes in real life. If you think sim is for sissies, a second hand oscilloscope and signal generator could be had for cheap.


----------



## SpudHarris

Anyone know the difference (apart from price) between OPA111AM and OPA111BM?


----------



## K3cT

I finally got my AD797BRZs back from my good friend since he borrowed them for his dual-mono CMOY. 

 My first impression is that if the OPA637BP is euphonic while AD843JNZ is dynamic then the AD797BRZ is "life-like". It's somewhere in between those two op-amps and I'm really liking it so far. Soundstage also seems to explode with these BRZs. OK, back to my music then as I need to get familiar with them.


----------



## majkel

AD843 is harsh and artificial for me. OPA637 is lifess and lacking PRaT. Actually, I prefer the OPA627 to it. Saying "life-like" contains much of the truth.


----------



## ROBSCIX

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_Nah, books are boring. I think it's a lot easier to understand things by doing. You should learn LTSpice so you don't have to make mistakes in real life. If you think sim is for sissies, a second hand oscilloscope and signal generator could be had for cheap._

 

I use multisim/EB, some spice, Proteus for microcontroller work and a few different apps for PCB design.


----------



## K3cT

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_AD843 is harsh and artificial for me. OPA637 is lifess and lacking PRaT. Actually, I prefer the OPA627 to it. Saying "life-like" contains much of the truth._

 

That's very interesting, majkel. I have to admit that I'm as clueless as it comes to electronics like ecclesand so my judgement is based on sound alone.

 I can see where you're coming from in regards of the AD843 but I must hear things differently with the OPA637. We seem to agree with the AD797 so that's good. No matter! Different circuits, different ears, YMMV etc. 
	

	
	
		
		

		
		
	


	




 I'm running those op-amps biased into class A if it helps. My current config is 2x AD797BRZ in left and right channels and OPA627BP in ground.


----------



## majkel

Remove class A for AD797. The only chip this helps it is OP27, real old school. Modern op amps are optimized to work without this trick.


----------



## K3cT

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Remove class A for AD797. The only chip this helps it is OP27, real old school. Modern op amps are optimized to work without this trick._

 

Maybe you're right but I'm having too much fun hearing music with this combination right now. 
	

	
	
		
		

		
		
	


	




 Thanks, I'll try your suggestion in the near future.


----------



## SpudHarris

I also like the 797's in class A. It may well be distortion and not natural but it sure is sweet to my ears


----------



## ROBSCIX

Some distortion is favorable to some people providing it is of the right order.


----------



## Kuze

So fellow head-fiers as of Nov 26 2009 whats the it Opamp to have?


----------



## SpudHarris

OPA827 & ADA4627-1 are the must haves at the mo......


----------



## K3cT

These AD797BRZs do not gloss the faults in the recordings unlike the OPA637BP which could either mean good or bad for certain people. Putting the more forgiving OPA627 in ground seems to match well with the neutral AD797s. 

 I have LT1028ACN8 and LT1124ACN8 en route to my place but I believe these AD797s are as good as it gets. To be honest, it has been increasingly difficult to tell these op-amps apart the more you spend time listening to them.


----------



## majkel

Biasing AD797 to class A doesn't transform them into warmer beast but the otherwise. They get more clinical and dry.


----------



## K3cT

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Biasing AD797 to class A doesn't transform them into warmer beast but the otherwise. They get more clinical and dry._

 

Stop tempting me to open up my amplifier again, majkel.


----------



## SpudHarris

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Biasing AD797 to class A doesn't transform them into warmer beast but the otherwise. They get more clinical and dry._

 

That's subjective and wholely dependant on the usual: Application, Phones, Other Components in the circuit (i.e OPA627's in ground) etc...etc... Personally the AD797's are fine as they are in my application but they sound better to my ears in class A.


----------



## Zerotohero

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Remove class A for AD797. The only chip this helps it is OP27, real old school. Modern op amps are optimized to work without this trick._

 

I have bb637bp and bb627ap in my assemblage 2.7 dac.
 I want to experiment with the class a mod for these chips.

 Can someone detail the mod so i can experiment with it please?


----------



## SpudHarris

Thought I had some better pics than this??

 2.2k resistor trick between pins 6-7.

 I tried this on the OPA637's and didn't like it at all and stress that it doesn't suit most of the ultra modern.... There is a certain amount of truth in what majkel says regards this but don't agree where the AD797's are concerned though 
	

	
	
		
		

		
		
	


	




.


----------



## diditmyself

OPA827 L/R and OPA627 is a wonderful combination. OPA627 in the ground channel adds a spark of magic, makes the vocals more intimate and centered and reduces the slightly artificially wide soundstage vs OPA827 in all positions. The sound is simply beautiful. It puts all my other amps to shame, discrete or opamp. It fulfills both of my wishes: neutral tonality and soundstage + musically and engaging presentation. The amp is a 3-ch 18V supply portable with diamond buffers. Listening impression via HD650.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_OPA827 & ADA4627-1 are the must haves at the mo......_

 

Just got in some ADA4627-1 yesterday and some new SOIC to Dip8 adapters today. Time to break out the soldering iron!
 BTW, also finally got in some resistors to try some class A biasing for certain units.


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Just got in some ADA4627-1 yesterday and some new SOIC to Dip8 adapters today. Time to break out the soldering iron!
 BTW, also finally got in some resistors to try some class A biasing for certain units._

 

Nice one Rob, let us know what you think of the 4627's.... It doesn't hurt to try but you will probably find the same as me that class A biasing doesn't suit all opamps. In some however it just wrings out that extra bit of something


----------



## majkel

The second one I liked biased into class A was LM6172. And that was all.


----------



## SpudHarris

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_The second one I liked biased into class A was LM6172. And that was all._

 

Not sure I've tried the 6171's and I haven't done any testing on duals at all, I assume the method is the same?


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Nice one Rob, let us know what you think of the 4627's.... It doesn't hurt to try but you will probably find the same as me that class A biasing doesn't suit all opamps. In some however it just wrings out that extra bit of something 
	

	
	
		
		

		
		
	


	


_

 

Yes, I understand it is not a procedure for all units but I have been keeping track of what units might benefit from this mod. I will let you know when I get the new units mounted and tested but ....I have about 6 new units to build.
	

	
	
		
		

		
		
	


	



 I am curious to see if there is any merit to the procedure. I must test before I make up my mind either way.


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_The second one I liked biased into class A was LM6172. And that was all._

 

There is one units I have never tested in any way. I have to put this unit on my shopping list next time I place an order for components.


----------



## ROBSCIX

Just received some new AD units, based on others opinions here I am going to be building a ADA4627-1 module. I will report my finding for anybody that is interested.


----------



## Bilavideo

I like the following chips:

 AD8566, AD823 (so, sue me), AD827, AD797BRZ, Opa 627


----------



## SpudHarris

I never mention the AD823 either because there are so many bashers of it but I really like it. Graham Slee uses it in the Solo so it can't be all bad, just needs the right circuit and complementary components to bring out the best in it. Not spent any time with the AD8566 though........


----------



## sachu

Quote:


  Originally Posted by *Zerotohero* /img/forum/go_quote.gif 
_I have bb637bp and bb627ap in my assemblage 2.7 dac.
 I want to experiment with the class a mod for these chips.

 Can someone detail the mod so i can experiment with it please?_

 

Nathan,

 I currently have the following in my DAC 2.7

 OPA627AP for the I/V (stock), OPA227 for servo (very low DC offset, better THD, PSRR figures compared to the OPA604 stock one), I also just switched from AD797 to the LME49710 (as i didn't have any decoupling scheme between the rails and also from rails to gnd)..I am liking what I am hearing now. The mids are nice and warm. The overall quality is forward sounding. I would like more clarity in the highs and so am waiting to change the I/V to THS4031 on Aries adapters. May switch back to the AD797 for the filters too at that point to see if they do better.
 Will need to add decoupling and bypass caps to this as well. Waiting for some boutique capacitors to arrive before i start taking the DAC apart.


----------



## K3cT

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Just received some new AD units, based on others opinions here I am going to be building a ADA4627-1 module. I will report my finding for anybody that is interested._

 

Any preliminary information regarding its sound characteristics? A comparison with the AD797 will be great.

 And am I right to assume that the best way to get these is directly from Analog Devices itself? Farnell is being crazy with the 30 Quids surcharge cost.

 EDIT1: Bah, scratch Farnell. Export restrictions prevent me from ordering them due to my location. 

 EDIT2: I can't order samples either from Analog due to my location in Indonesia. 
	

	
	
		
		

		
			





 I'll try contacting their CS and see what whey have to say.


----------



## Zerotohero

Is there a sonic difference between the opa227 and the opa604?

 I tried opa637bp in the iv of my 2.7 and it didn't like it so switched back to opa627ap.
 For buffers i cant decide between 627ap and 637bp - I think 637bp is more accurate but less prat than the 627ap


  Quote:


  Originally Posted by *sachu* /img/forum/go_quote.gif 
_Nathan,

 I currently have the following in my DAC 2.7

 OPA627AP for the I/V (stock), OPA227 for servo (very low DC offset, better THD, PSRR figures compared to the OPA604 stock one), I also just switched from AD797 to the LME49710 (as i didn't have any decoupling scheme between the rails and also from rails to gnd)..I am liking what I am hearing now. The mids are nice and warm. The overall quality is forward sounding. I would like more clarity in the highs and so am waiting to change the I/V to THS4031 on Aries adapters. May switch back to the AD797 for the filters too at that point to see if they do better.
 Will need to add decoupling and bypass caps to this as well. Waiting for some boutique capacitors to arrive before i start taking the DAC apart._


----------



## sachu

Quote:


  Originally Posted by *Zerotohero* /img/forum/go_quote.gif 
_Is there a sonic difference between the opa227 and the opa604?

 I tried opa637bp in the iv of my 2.7 and it didn't like it so switched back to opa627ap.
 For buffers i cant decide between 627ap and 637bp - I think 637bp is more accurate but less prat than the 627ap_

 

There was a definite reduction in noise floor with the OPA227 and the highs cleared up and added a little air to the highs as well. 

 I'd stick to the OPA627BP/AP for the I/V, unless you are confident in doing some DIY work switching to THS4031s here would be ideal. For the buffer/filter the AD797 still does sound better. The LME49710 was cluttering up the high frequencies. I however am yet to put in proper decoupling caps on the AD797. Just been too consumed with other stuff.


----------



## ROBSCIX

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Any preliminary information regarding its sound characteristics? A comparison with the AD797 will be great.

 And am I right to assume that the best way to get these is directly from Analog Devices itself? Farnell is being crazy with the 30 Quids surcharge cost.

 EDIT1: Bah, scratch Farnell. Export restrictions prevent me from ordering them due to my location. 

 EDIT2: I can't order samples either from Analog due to my location in Indonesia. 
	

	
	
		
		

		
		
	


	




 I'll try contacting their CS and see what whey have to say._

 

I haven't got around to testing.


----------



## K3cT

I'm looking forward to it, ROBSCIX. Have you gotten the actual op-amps? 

 I think I'm gonna order 2 for the sake of curiosity but these are unusually expensive for an op-amp.


----------



## ROBSCIX

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_I'm looking forward to it, ROBSCIX. Have you gotten the actual op-amps? 

 I think I'm gonna order 2 for the sake of curiosity but these are unusually expensive for an op-amp._

 

Yes, I have 4 of them. Along with some adapters. I just have to assemble the units.
 You have to remember that audio is just one thing opamps are used for. You cannot really use price as a quality indicator.


----------



## ROBSCIX

I got in some new LT models also. I will hopefully get a chance to test them out tomorrow sometime and I will let you know what I think.


----------



## K3cT

Probably a stupid question but if the amplifier is 3-channel like the PPAv2 or M^3, is it possible to stick a dual-channel op-amp like the LT1364 in there? If it's not possible, is there an adapter that allows you to do so?


----------



## gurubhai

Anyone tried the OPA2137p ?

 My initial impressions are very good, really sounding amazing with my current setup.


----------



## SpudHarris

Never heard of that one. But might as well give it a try as I'm always looking for a giant killa'. Ordered from Farnell (£1.49) bet it will sound like every penny


----------



## gurubhai

^^I think you would be very pleased with these.I just can't stop listening since I swapped these in.


----------



## sachu

Just dropped in the THS4031 on homemade adapters (thanks Don) for the I/V replacing the OPA627APs in my DAC 2.7 and wow..It just blows away the Sonic Frontiers Trans DAC with similar chips in the I/V and filter as my DAC 2.7

 The music just has huge amounts of body to it, lot better details, greater prat, strings are to be heard to be believed, bass deep, hard and fast enough to satisfy even a basshead like me. Also by far most easily noticable is the huuge soundstage the DAC 2.7 puts out compared to the Trans DAC. 

 I plan to monitor the power rails at all the chips and make sure the outputs aren't oscillating, if any counter them with more decoupling and bypassing caps as needed.
 Before i dropped in the THS chips most of my previous observations held true save for the fact that the transDAC had slightly better details in the highs but still lacking the separation taht the DAC 2.7 brought to the table.

 With the THS chips in place the DAC 2.7 outperforms the TransDAC in that arena as well..mighty pleased.


----------



## sachu

Been listening and comparing a while now...the only area the TransDAc eclipses the DAC 2.7 is the bass impact..its got slightly bigger bass but doesn't feel as composed. 

 The DAC 2.7 shines on spatial presence and creates an air around each instrument making them feel alive..fantastic sources both of them.


----------



## ROBSCIX

Great that it works for you. The THS403X opamps are usually very touchy and can become unstable in some circuits.
 I thought they sounded quite good, when I heard them tested in a couple of DAC' designs.


----------



## forciano

I have been strongly considering buying the OPA 637SM + Adaptor for my recently purchased Asus Essence ST sound card, but it costs $250 on a website I found. 

 I will continue searching online, but if anybody knows where I can get it cheaper than that I would really appreciate it.


----------



## dean0

digikey is a good source


----------



## gurubhai

After a few long listening sessions, I can safely say now that OPA2137P is now my favorite opamp with the current setup.
 It has the best bass I have ever heard from my modded HD580s,both in quantity & quality.
 At the same time, it also provides excellent treble detail & lush mids.
 My friend's DT880 600ohm also sound excellent with these, so they seem to love high impedance cans.


----------



## 12Bass

Quote:


  Originally Posted by *gurubhai* /img/forum/go_quote.gif 
_After a few long listening sessions, I can safely say now that OPA2137P is now my favorite opamp with the current setup.
 It has the best bass I have ever heard from my modded HD580s,both in quantity & quality.
 At the same time, it also provides excellent treble detail & lush mids._

 

Perhaps you might tell us which others you have tried for comparison?


----------



## gurubhai

I have tried most dual opamps.
 the ones I can remember:
 TI : OPA2111,OPA2107,OPA2132,OPA2127
 Linear:LT1361,1364,1358,1057,1124,1212 & few others
 National:49720NA &HA,49860,4562 etc.


----------



## forciano

Thx for the replies, time to do some more research on this


----------



## K3cT

I keep coming back to the AD797BRZ so I think I know what kind of sound I'm looking for now. I've now put the LT1028 in Ground to add that little warmth and midrange magic and so far, I'm liking this combination a lot. The soundstage of this AD797BRZ is really, really good but perhaps too wide for certain genres like rock where intimacy is preferred. 

 Next in-line for my tests are LME49710HA and ADA4627-1BRZ. Nigel is very impressed with the latter so I have to get them as well.


----------



## ROBSCIX

I used to use the AD797, I still test it out from time to time in various circuits. I find it has great sound but there are others that I like better. YMMV.


----------



## K3cT

For some weird reason, I cannot use LT1028 in signal because the left channel emit a buzzing noise while the right channel functions normally. I'm perplexed.


----------



## ROBSCIX

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_For some weird reason, I cannot use LT1028 in signal because the left channel emit a buzzing noise while the right channel functions normally. I'm perplexed._

 

Did you verify the opamp is OK and not malfunctioning ? I would just swap the opamps and see if the issues pops up in the right channel. If it is ok, then you have to consider other possibilities...


----------



## K3cT

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Did you verify the opamp is OK and not malfunctioning ? I would just swap the opamps and see if the issues pops up in the right channel. If it is ok, then you have to consider other possibilities..._

 

Yes, I think that goes without saying. 
	

	
	
		
		

		
		
	


	




 I tried the op-amps on a friend's dual-mono CMOY and they work.

 The left channel emits something like a buzzing noise if 2x LT1028 are used in the signal, it's not silent. It's really strange.


----------



## diditmyself

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Yes, I think that goes without saying. 
	

	
	
		
		

		
			





 I tried the op-amps on a friend's dual-mono CMOY and they work.

 The left channel emits something like a buzzing noise if 2x LT1028 are used in the signal, it's not silent. It's really strange._

 

It sounds like it's oscillating.


----------



## ROBSCIX

That would be my guess. I wonder why on only one side?
 Inspect the adapter is there anything that is different about the one side?


----------



## Mad Max

Finally got time now to play with my portable rig. I'm really liking this TLE2141A, and next is TLE2071A. Have any of you tried these?


----------



## K3cT

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_It sounds like it's oscillating._

 

Then why it works fine if I put it in ground channel? 

  Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_That would be my guess. I wonder why on only one side?
 Inspect the adapter is there anything that is different about the one side?_

 

I actually noticed that the DIP8 socket is kinda wonky on one side so the op-amp cannot sit flush completely but then the others work fine and only the LT1028 is problematic.


----------



## ROBSCIX

High speed opamps can become unstable for many reasons.


----------



## ROBSCIX

I have been considering designing and fabricating some custom built adapters.
 Do any of the DIY nuts in here have any ideas of some features that would be great to see on some opamp adapters?
 I have a few ideas, but I am interested to hear what others have to say as necessity is the mother of invention so if you need particular features chances are others do also.


----------



## ROBSCIX

I have been considering designing and fabricating some custom built adapters.
 Do any of the DIY nuts in here have any ideas of some features that would be great to see on some opamp adapters?
 I have a few ideas, but I am interested to hear what others have to say as necessity is the mother of invention so if you need particular features chances are others do also. If you have some ideas lets hear them...


----------



## qusp

multiple supply bypasses for taming fast opamps, class A resistor pads, grounding pads/holes. basically what i already have. I cant think of another thing I want that these ones I got have (except maybe silver immersion plating 
	

	
	
		
		

		
		
	


	




 guys they are awesome!! will send some pics in the next day or 2.


----------



## ROBSCIX

Yes, I was already considering points of the circuit for adding additional components for various tasks.
 If you have some cool adapters let us see them...


----------



## Mad Max

With F-Zero decals


----------



## Mad Max

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_... I actually noticed that the DIP8 socket is kinda wonky on one side so the op-amp cannot sit flush completely but then the others work fine and only the LT1028 is problematic._

 

As long as it gets a tight, snug fiit to where you cannot make it wobble very easily with a slight nudge it should not give you problems as far as fit is concerned. You might have to carefully bend the leads ever so slightly to get it right. The same thing has happened to me when testing opamps in my dac - a couple did not get a relatively "rock-solid" fit in the 2x1 adapters I have. In my case, I just bent the leads on one side slightly outward to get a tighter fit. My adapters are also slightly wonky on one side as you describe. =\


----------



## diditmyself

I've found that LT1028 is as cranky as an opamp gets. When I dropped it in one of my otherwise stable amp (and I've tried quite a lot of opamps in it) there was oscillation. I had to add compensating caps to tame it. It's funny that the sound was the same with or without oscillation. I think it's brighter than neutral and because of that gives the impression of being spacious and detailed.


----------



## qusp

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Yes, I was already considering points of the circuit for adding additional components for various tasks.
 If you have some cool adapters let us see them..._

 

will do, soldering some up for a DAC mod tomorrow, will post some pics then


----------



## K3cT

I've given up making the LT1028 work in signal. I'm pretty happy with AD797 in signal and LT1028 in ground for the moment so that will settle until I have new toys to play with.


----------



## ROBSCIX

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_will do, soldering some up for a DAC mod tomorrow, will post some pics then_

 

Great, post them up when you have some time.


----------



## MargaretB

I'd like some advice on how to configure my stx.

 As I understand it the asus xonar essence stx default opamps are:

 1.) 1 x LME4562NA which is used as a single ended buffer to correct the signal level to line out standards.
 2.) 2 x JRC2114D which are used to convert the Current output from the DAC to a voltage.

 I have a few OPA2111 and OPA2137 opamps and I'd like to know what would be, in your opinion, the best configuration for the card.

 for example I know, gurubhai has tried OPA2137 in I/V and he said he liked it a lot (funny though, I just looked at his signature and it seems he's switched to OPA2111)

 gurubhai: have you tired OPA2137 in buffer and OPA2111 I/V? How about OPA2111 buffer and OPA2137 I/V?

 Any input would be appreciated guys, thanks.


----------



## opamp_addict

Here's the new adapter just for metal can type Opamp. Hard to come by and doesn't come cheap.


----------



## gurubhai

@MargaretB : I posted in Xonar thread regarding burr-browns.
http://www.head-fi.org/forums/6250824-post1133.html


----------



## Lavcat

Quote:


  Originally Posted by *forciano* /img/forum/go_quote.gif 
_I have been strongly considering buying the OPA 637SM + Adaptor for my recently purchased Asus Essence ST sound card, but it costs $250 on a website I found. 

 I will continue searching online, but if anybody knows where I can get it cheaper than that I would really appreciate it. 
	

	
	
		
		

		
			



_

 

Since I've been looking recently, 4Star In-Stock OPA637SM - 4 Star Electronics 877-240-8595 and Newark TEXAS INSTRUMENTS|OPA637SM|Operational Amplifier (Op-Amp | Newark.com have stock of the OPA637SM. Any way you look at it though, the part is expensive.

 I currently use a pair of OPA627BM's in my Auzentech HomeTheater, and I'd like to try the OPA637SM's biased to class A.


----------



## Lavcat

Quote:


  Originally Posted by *opamp_addict* /img/forum/go_quote.gif 
_Here's the new adapter just for metal can type Opamp. Hard to come by and doesn't come cheap._

 

Where from? For my purposes I'm sure BrownDog would do just fine, but from the picture this looks more like the ones offered by Auzentech.


----------



## qusp

as promissed Robsix, here's the adapters

 first is OPA827 x 2 with several decoupling and bypass caps with silver ground wire








 next is 2 x OPA211 also with multiple blackgate and vishay caps and with more positions to fill. this one I made my own silver pins though









 the other device is one of the SSB01 discrete diamond buffers

 loving the OPA827 in the new ibasso fiquest


----------



## qusp

also I bought some adapters for metal can types on ebay and they were only a couple of dollars


----------



## sachu

So it appears the OPA227 instead of OPA627 for I/V duty just sounds so much better.
 It is more lively, crisper, better details with a more forwardish mids.
 Took me by surprise.


----------



## qusp

OPA627 aint all that IMO. I prefer many opamps to this chip


----------



## SpudHarris

I also prefer many other chips to the 627's and even 637's. ADA4627-1's and AD827's are both better IMO. But the Fi-Quest makes a lot of Opamps shine.......


----------



## ROBSCIX

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_as promissed Robsix, here's the adapters

 first is OPA827 x 2 with several decoupling and bypass caps with silver ground wire

 next is 2 x OPA211 also with multiple blackgate and vishay caps and with more positions to fill. this one I made my own silver pins though

 the other device is one of the SSB01 discrete diamond buffers

 loving the OPA827 in the new ibasso fiquest_

 

Very nice!


----------



## ROBSCIX

Quote:


  Originally Posted by *Lavcat* /img/forum/go_quote.gif 
_I currently use a pair of OPA627BM's in my Auzentech HomeTheater, and I'd like to try the OPA637SM's biased to class A._

 

I have the OPA627 and 637SM's but I have not tried them Biased to class A yet. Maybe something to check out.
 I have built similar units for friends.


----------



## ROBSCIX

Quote:


  Originally Posted by *sachu* /img/forum/go_quote.gif 
_So it appears the OPA227 instead of OPA627 for I/V duty just sounds so much better.
 It is more lively, crisper, better details with a more forwardish mids.
 Took me by surprise._

 

I always liked the OPA2227 for bass channels. The chip has a very refined tight bass.


----------



## qusp

thanks Rob, dont know if youve got any tips here. I have a liking for the cardas organic noclean flux in pretty much any situation, small SMD is definitely not an exception. often I dont bother about cleaning it off as its is not required; but with these white PCBs and with the flux getting a bit old and dark, it looks downright grubby. I have tried isopropyl alcohol and it usually does a pretty good job, but i've run out of that. i'll probably get some more and its really just for aesthetics as it doesnt effect the operation. do you have any recommendations for home remedies to clean it properly? the buffer PCBs are pretty sexy little PCBs and its a shame to have them looking so grubby. the one in the frame is ok, but could be better; I used some gin and an old toothbrush to clean that one 
	

	
	
		
		

		
		
	


	




, but the one in the background with the Nichicon caps (fine gold) I havent cleaned at all and it shows. the way it is it could look to some that I have used to much heat or something, even though the condition of the joints should say otherwise due to being nice and shiny and smooth. maybe i'm just vain.....
	

	
	
		
		

		
		
	


	




 i've got a new tub of flux on the way, when new the flux is much lighter, but I would like to know if others have a better method for cleaning up work after its finished. most of the time of course these things are sealed inside boxes and it doesnt matter, but I know and thats enough to bother me.


----------



## Lavcat

Acetone works well and can be bought at drugstores, sold for polish remover. Get pure actetone though. Most polish remover has oil and fragrance and other stuff.


----------



## diditmyself

The sound of OPA627 is very good compared to whatever, but it's not neutral. It sounds soft and warm and adds some kind of "life". Since many other opamps sounds thin, harsh or cold, OPA627 is perfect to use in the ground channel to balance the slightly thin and lifeless sound of other almost perfect opamps like OPA827, AD797 LME49720 or LT1028. I really love the combination of OPA827 and OPA627. It's hard to imagine anything better than this, but on the other hand there's nothing in life that's perfect.


----------



## qusp

thanks, yeah I had wondered about acetone. zero residue from that too. so there is no problem with it dissolving the dielectric on the PCB?


----------



## qusp

ok I might try 627 in ground then, since my fave opamps at the moment are 3 of the 4 you mention. I had thought about doing that using the same logic as you, considering OPA627/37 are kind-of the tube of the opamp world. favorite at the moment is OPA827, with the national chip and 797 coming close behind. I have only used the LT1028 in circuits where it was not directly in the I/V and so hard to know its character


----------



## Lavcat

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_thanks, yeah I had wondered about acetone. zero residue from that too. so there is no problem with it dissolving the dielectric on the PCB?_

 

I used to be the president of a company making digital cameras. We used acetone for board re-work. No problems except need for ventilation.


----------



## qusp

cool, well that sounds like the ticket then; thanks for the tip!! 
	

	
	
		
		

		
			





 I love this board

 my workshop is downstairs under the house and semi-open, so will just set up the fan like I normally do on calm days to avoid solder/flux fumes


----------



## ROBSCIX

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_thanks Rob, dont know if youve got any tips here. I have a liking for the cardas organic noclean flux in pretty much any situation, small SMD is definitely not an exception. often I dont bother about cleaning it off as its is not required; but with these white PCBs and with the flux getting a bit old and dark, it looks downright grubby. I have tried isopropyl alcohol and it usually does a pretty good job, but i've run out of that. i'll probably get some more and its really just for aesthetics as it doesnt effect the operation. do you have any recommendations for home remedies to clean it properly? the buffer PCBs are pretty sexy little PCBs and its a shame to have them looking so grubby. the one in the frame is ok, but could be better; I used some gin and an old toothbrush to clean that one 
	

	
	
		
		

		
		
	


	




, but the one in the background with the Nichicon caps (fine gold) I havent cleaned at all and it shows. the way it is it could look to some that I have used to much heat or something, even though the condition of the joints should say otherwise due to being nice and shiny and smooth. maybe i'm just vain.....
	

	
	
		
		

		
		
	


	




 i've got a new tub of flux on the way, when new the flux is much lighter, but I would like to know if others have a better method for cleaning up work after its finished. most of the time of course these things are sealed inside boxes and it doesnt matter, but I know and thats enough to bother me._

 

No sorry, I don't really have any tricks to let you in on. I wish I did.
 I have a similar "perfectionist" thing going on when I work with audio electronics. If you figure out any good one please let us know.


----------



## diditmyself

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_ok I might try 627 in ground then, since my fave opamps at the moment are 3 of the 4 you mention. I had thought about doing that using the same logic as you, considering OPA627/37 are kind-of the tube of the opamp world. favorite at the moment is OPA827, with the national chip and 797 coming close behind. I have only used the LT1028 in circuits where it was not directly in the I/V and so hard to know its character_

 

LT1028 isn't a favourite, I just mentioned it because some people like it and it's on the bright side. I would rank the opamps almost like you did with OPA827 on top and AD797 before LME497x0. Besides the very neutral, detailed sound with great soundstaging, OPA827 also has the advantage of "no" bias currents and extremely good DC precision, and it doesn't need any compensation at "normal" gain.


----------



## qusp

indeed I have found the OPA827 to be a top performer and exceedingly flexible. the amp i'm using it in at the moment has a VERY WIDE range of gain; you can set it anywhere from 1.3 to well over 15 (depending on feedback and amount of stacked buffers can get close to 1.5W output into 16ohms 
	

	
	
		
		

		
		
	


	




 not bad for portable). the OPA827 will behave itself very well all the way through that range with good balance and consistency throughout; the LME497X0 on the other hand does not like the low gain settings at all and produces quite a bit of bass roll-off, loses dynamics and basically becomes unlistenable. I tend to use my JH13 with this amp almost exclusively, so AD797 and even OPA211 (with a cap straight across the supply) come out ahead of the national chip. 

 i've only just got this amp and its very tweakable. one of the buffer configurations alters the output impedance of the amp to increase stability with some opamps, good chance this may be playing havock with the low impedance JH13 as well I guess. there is much experimentation before I have my head fully around the possibilities with the OEM; but from early impressions it will be WELL worth it in the end (lol, since when is there an end)


----------



## qusp

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_No sorry, I don't really have any tricks to let you in on. I wish I did.
 I have a similar "perfectionist" thing going on when I work with audio electronics. If you figure out any good one please let us know._

 

cool, no probs. yeah its a curse 
	

	
	
		
		

		
		
	


	




 i'll try out the acetone thing and report back


----------



## SpudHarris

Hi Jeremy, did you get any rest at all? This OEM is gonna burn us all out. I find myself staying up later and later just listening and drinking (neither doing me any good). I am also using OPA827's with Hi-C buffers (not via the switch though) and a class A LME49710 in ground, it's by far the best combo I've found. Lightning fast and transparent but oh the bass........

 I've found another little 'thing' with the Fi-Q.... I like the 4 channel set up but if the battery is low and you try to listen via the PSU it hisses like mad untill the battery fills up?? Ryuzoh has told me to remove R20 and jumper it which I'm gonna do today cuz 4 channel with this chip set gives more air IMO...


----------



## diditmyself

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_the LME497X0 on the other hand does not like the low gain settings at all and produces quite a bit of bass roll-off, loses dynamics and basically becomes unlistenable._

 

This is also my experience from using LME497x0. It's not suitable to use at unity gain. It's unity gain stable, but an oscilloscope reveals quite a lot of peaking (picture below). It can be used at lowish gain with proper compensation.


----------



## SpudHarris

Anyone have experience of the different (ARZ - BRZ) AD797's? I have ARZ's and love them but just wondered if the £24 for two BRZ's was worth the upgrade.....


----------



## qusp

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Hi Jeremy, did you get any rest at all?_

 

Hey Nigel, yeah I caught a few hours. thats pretty normal for me at least 3 nights of the week. I usually stay up till about now (4am AEST) and get up about 9-10 if i'm lucky. tending to try to catch up and sleep in at least one day a week.

  Quote:


 This OEM is gonna burn us all out. I find myself staying up later and later just listening and drinking (neither doing me any good). 
 

lol, yep, thats about the size of it; I spend the day soldering and then I break after work and spend my spare time soldering and listening/tweaking. but this amp sure is a bit of fun. OPA827 is a dream in it. im not sure about the national chip as buffer. this instability at low gain has me worried a bit. i'm going to have a look into the datasheets for app notes to see if I can make it behave itself. I do wonder about using this chip with class A resistors. it should be operating in class A already without them in this circuit.

  Quote:


 I am also using OPA827's with Hi-C buffers (not via the switch though) and a class A LME49710 in ground, it's by far the best combo I've found. Lightning fast and transparent but oh the bass........ 
 

hmm, ok well i'll try it out again tomorrow and see what I think; the amp is really starting to come into its own. (just in time for me to throw it into a spin. i'll be doing the regulator mod tomorrow and setting those jumpers; which by the sounds of it; as we suspected have more to them than improving 4 channel operation. I wonder why the cloak and dagger? have you measured for DC at the output with R20 installed I wonder if that has anything to do with the hiss and that would also explain why the tight lips.

  Quote:


 I've found another little 'thing' with the Fi-Q.... I like the 4 channel set up but if the battery is low and you try to listen via the PSU it hisses like mad untill the battery fills up?? Ryuzoh has told me to remove R20 and jumper it which I'm gonna do today cuz 4 channel with this chip set gives more air IMO... 
 

check for DC at the output before you remove it. i'm going to.i'm undecided about 4 channel. I think I prefer 3 personally, perhaps I just havent found the right chip for ground yet. i'll try out the OPA627/37 soon I emailed Ti to see what they would charge me for a metal can

 also I ordered some more chips last night, but many wont arrive for a week or 2. I ordered the new OPA2107 (AU and AP version), OPA830, OPA2376, and the old favorite OPA228 also ordered some low voltage regs (LM317/337) for some shunted 1.2v supplies for the ackodac. none of my super regulators will behave down that low. lastly got some TLE2426 rail splitters for spinning a ground in this BB dac project. gonna grab some texas components Zfoil resistor networks for passive rail splitting too and see which works best.

 I really need to find a hobby that isnt so closely tied to my work 
	

	
	
		
		

		
		
	


	




 and I gotta get some sleep.......zzzzzz................now........zzzzz zzzz

 night night


----------



## majkel

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Anyone have experience of the different (ARZ - BRZ) AD797's? I have ARZ's and love them but just wondered if the £24 for two BRZ's was worth the upgrade....._

 

It's like digital (AN) against vinyl (BRZ). I have never tried the ARZ, though but it should be like AN/ANZ, just in a different package.


----------



## SpudHarris

Thanks Majkel, so which version are you using and which is the absolute best version. I may be able to get BN's, will this be an improvement over the AN or ARZ?

 Also do you use any tricks or mods with yours?


----------



## ROBSCIX

Yes, do you have any tweaks?


----------



## devast

Get some ADA4627 if you haven't already. I'm using it in a low-pass filter circuit in my dac, and it really sounds great and neutral(for my ears).


----------



## levin

hey guys, i just read a few post about AD797BRZ's and i might give them a go. just wondering where would i be able to obtain the adapter for these. and if i am not wrong these will go into the buffer area? if so would there be any complimentary opamps for the i/v


----------



## SpudHarris

Lots of people use Brown Dogs But you can also get similar stuff of e-bay.

 Not sure if they are suitable for your buffer channels though as they are quite tempramental, others will comment on this though. There's a lot about the 797's on the Fi-Quest thread as they are our weapon of choice.


----------



## K3cT

I've never used the ARZ version but the other version is one of my favorites and I find that I keep coming back to them. I love the gobs of details and soundstage these AD797s give me.

 Anyway, I've managed to make the LT1028 work in my amplifier with a little help from a close friend and am trying 2x LT1028 in signal and AD797 in ground. So far so good!


----------



## leeperry

ditto! I love 4*AD797BN on the DAC output and 2*LT1028ACN8 as final buffer, fantastic combo 
	

	
	
		
		

		
		
	


	








 the 797B just has this totally versatile SS(no other chip I've heard can touch its SS), and the 1028A a very balanced/detailed sound w/ a fantastic non-bloated low end bass response 
	

	
	
		
		

		
		
	


	




 797B stays! but I'll try LT1677IN8 as buffer again, it's even more detailed but a tad too bright...and sort of "one color" only as Andrea would say


----------



## K3cT

I see those monster Mundorf caps are missing now on your soundcard, leeperry.


----------



## leeperry

yeah, they come and go! so far I love this combo, it's about finding combos that work together ya know 
	

	
	
		
		

		
		
	


	




 1028A as DAC LPF sounds very thin, and so does 797B as buffer...but the opposite sounds amazing!


----------



## ROBSCIX

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_I've never used the ARZ version but the other version is one of my favorites and I find that I keep coming back to them. I love the gobs of details and soundstage these AD797s give me.

 Anyway, I've managed to make the LT1028 work in my amplifier with a little help from a close friend and am trying 2x LT1028 in signal and AD797 in ground. So far so good! 
	

	
	
		
		

		
		
	


	







_

 

Were you having troubles with oscillation?


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Lots of people use Brown Dogs But you can also get similar stuff of e-bay.

 Not sure if they are suitable for your buffer channels though as they are quite tempramental, others will comment on this though. There's a lot about the 797's on the Fi-Quest thread as they are our weapon of choice._

 

I actually found the BD a bit flimsy, a pin on one of the adapters was bent and trying to rectify it only suceeced in breaking it off. I have an associate sending me higher qulaity units from Asia.
 I think I might just dig into my education and design and fabricate some of my own.


----------



## Lavcat

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I actually found the BD a bit flimsy, a pin on one of the adapters was bent and trying to rectify it only suceeced in breaking it off. I have an associate sending me higher qulaity units from Asia.
 I think I might just dig into my education and design and fabricate some of my own._

 

What were the adapters you used in your Forte review on guru3D? They did not look like BrownDog. Were they the ones from Auzentech?


----------



## ROBSCIX

Quote:


  Originally Posted by *Lavcat* /img/forum/go_quote.gif 
_What were the adapters you used in your Forte review on guru3D? They did not look like BrownDog. Were they the ones from Auzentech?_

 

 Those are Auzentech branded opamps. 

 I don't use Browndogs, I tried them once and they were quite flimsy as I said a leg broke off just from straightening it out. I have been sent many other types from contacts around the world but I have been seriously considering just making my own. As they say, if you want something done right do it yourself.
 We will see, I have too many project on the go as it is.


----------



## K3cT

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Were you having troubles with oscillation?_

 

On the first thought yes but upon a closer inspection, it turned out that it was a hum loop problem caused by a loose DIP socket.


----------



## ROBSCIX

Atleast you found the issue.


----------



## SpudHarris

Just got an e-mail from Farnell saying they are waving the carriage charges for US stock delivered to the UK. I want to take advantage but apart from the AD797BRZ's I can't really think of any other must haves.

 I luuuuuuve the TO-99 versions of the 49710 and already have a few put aside (for a rainy day 
	

	
	
		
		

		
		
	


	




) can you guys recommend any other metal can must haves???


----------



## LingLing1337

I have 3x LME49720NA coming in to replace the TL082CN in my Decco. I'll post impressions when I get them installed.


----------



## SpudHarris

I have a couple of AD825's to test this evening (can't remember what they are like) If I like them I'm gonna order one of these dual modules


----------



## leeperry

mundorf 0.1uf MKP decoupling caps(V-/V+) on my soundcard were increasing the bass percussion, but lowering its extension....so why not trying w/ and w/o by yourself?

 I personally wonder about AD8620/AD8599, some rave about them...some call them worthless, and they're not exactly cheap as I'd need 4 of each 
	

	
	
		
		

		
		
	


	




 I just wonder if in the mean time AD has made some AD797B killers? 
	

	
	
		
		

		
		
	


	




 a few days ago I tried to replace my LT1028A finall buffer by OPA1611, hah...not good!! ugly BB sound, and I also tried OPA827...way too colored compared to the 1028A, it was killing the AD797B altogether. I'll try LT1115


----------



## Mad Max

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_...
 a few days ago I tried to replace my LT1028A finall buffer by OPA1611, hah...not good!! ugly BB sound, and I also tried OPA827...way too colored compared to the 1028A, it was killing the AD797B altogether. I'll try LT1115 
	

	
	
		
		

		
		
	


	


_

 

How is the OPA827 colored?


----------



## leeperry

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_How is the OPA827 colored?_

 

hard to explain,I've never liked the BB sound to begin w/...it wasn't as bad as the OPA1611, though..but LT1028A is simply far more transparent and so much better sounding(as final buffer on my HD2).


----------



## majkel

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_How is the OPA827 colored?_

 

Simply it is. 
	

	
	
		
		

		
		
	


	




 Hard to call this color, maybe pleasant but unnatural.


----------



## 12Bass

Hmmm... haven't yet heard an op amp which doesn't impart some sort of change into the sound, which implies that they are all colored in one way or another.

 As to talk about the "Burr-Brown sound", I don't hear much similarity between, say, OPA2134 and OPA211 or OPA827. Pretty different overall....


----------



## majkel

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Hmmm... haven't yet heard an op amp which doesn't impart some sort of change into the sound, which implies that they are all colored in one way or another._

 

Every single component does it. All you have to do is compensate one for another, combining several of them in order to create resulting neutrality. 

 In the meantime, try OPA228P offset pins supplying. This one is another league than any other op-amp. I think the most transparent op-amp per say is AD8021 when used as described in the datasheet. I mean Rf and Cf values respected.


----------



## SpudHarris

At present I'm sold on the AD797's, they are just superb in my Fi-Quest. I have just ordered the BRZ versions as I only have ARZ's at the mo....

 Anyone have experience with the LT1115 ?? LT has it listed as an ''Audio'' Op Amp. Just wondered if they were worth a punt?


----------



## diditmyself

OPA827 is "way too colored"? I don't understand this. It's one of the most neutral opamps I've heard in every aspect - tonality, soundstage, PRAT etc. It might be a little "light" like most of the newer and better opamps. Maybe it's becuase they're "all" dominated by odd order harmonics and have almost no 2nd order.

 I agree with Majkel that the way to go is to balance the sound with different parts. When using amps with ground channel it's easy to do this by choosing the right blend of opamps.

 If one's used to bipolar opamps, I can understand that JFET input opamps can sound grainy, even dirty, aggressive, dry and earthbound.

 I think we evaluate (op)amps differently. Long time listening is no 1, but I usually add the tested amp to the audio chain, sticking it in between DAC and amp to hear how it alters the sound. If you just roll opamps you have no true reference.

 To my ears LT1028 isn't neutral.


----------



## leeperry

well, whatever rocks your boat eh 
	

	
	
		
		

		
		
	


	




 I looooove the AD797B on the DAC output of my HD2(and believe me, I tried tons of chips)...it makes a killer combo w/ LT1028A! uber-versatile SS > very percussive low end bass, untouched SS from the 797B, HD-sounding mids and non-whiney trebles...impressive 
	

	
	
		
		

		
		
	


	




 OPA827 clearly didn't sound as capable/versatile as LT1028A...and OPA1611 was the icing on the cake, hah..unbearable.

 and we all use different designs, DACs, voltages, decoupling caps...we're mostly here to share experiences as I understand it. I could prolly live w/ the OPA827(even though it kills the 797B SS), but 1611 would be out of the question(I guess you all tried this chip too!)

 to me the BB chips are completely incapable of doing stuff the LT/AD can do in a snap...that's what I'd call the BB sound = sheer incompetence.


----------



## opamp_addict

Finally got some time to listen to some opamps. I quite like the OPA1611, AD8620 and especially OPA827.


----------



## SpudHarris

Agree on the OPA827 for sure, nice opamp! I had high hopes for the ADA4627's also because a reliable source told me that they would out perform the likes of OPA637's, IMHO not the case....

 I have just received and soldered up 2 # AD797BRZ's, I have had the ARZ's for ages and love them to bits (for sure my favourite by miles). Well the BRZ's do cost nearly twice as much as the ARZ's so maybe it's a bit of placebo but they do seem to have slightly more of everything. Just knowing that they are a higher spec version is enough to make me keep them in place 
	

	
	
		
		

		
		
	


	




 For the record, the OPA827 is my second favourite.


----------



## bibo01

Dear forumers,

 It is my intention to mod the BB2227 op amps onboard of my LynxTwo-B card.

 For best op-amps, given my inexperience, I privately asked for help to fellow forumer - Majkel. He kindly suggested OPA228P or, eventually, OPA227P.
 Do you agree that it is the best op-amp for me?
 What are the sonic properties of such op-amps?
 I noticed that there are various types of OPA228. 
 Would I need the "P" type? Is it the right size?

 Anyway, I would need two of these chips for each one I intend to replace. Therefore, I would also need 2to1 adapters.
 Looking on eBay, do you think that either one of these would be good?:
DIP8 8 Pin Gold-Plated Socket,For DIP-8 OP-AMP IC, x10 - eBay (item 250490857879 end time Jan-27-10 19:11:09 PST)
Lot of 12x Adapters Two Single to One Dual Op-Amp - eBay (item 370229599635 end time Feb-09-10 06:56:29 PST)

 If you can suggest a place where I can order the whole package, it would be great.

 At this link there is a photo of the card:
http://www.head-fi.org/forums/f6/lyn...1/#post6318071

 Thanks a lot for all your suggestions.


----------



## K3cT

I'm a bit conflicted now. There is something magical about LT1028's vocal and midrange presentation that are sorely missing in the other op-amps.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Just got an e-mail from Farnell saying they are waving the carriage charges for US stock delivered to the UK. I want to take advantage but apart from the AD797BRZ's I can't really think of any other must haves.

 I luuuuuuve the TO-99 versions of the 49710 and already have a few put aside (for a rainy day 
	

	
	
		
		

		
			





) can you guys recommend any other metal can must haves???_

 

The TO-99 LME49710HA is still one of my favorites. I know of a few metal can opamps that are said to be great for audio...They get very pricey though.

 Everytime I come here you guys remind me of how many new units I still have to build and test.


----------



## fzman

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_There is something magical about LT1028's vocal and midrange presentation that are sorely missing in the other op-amps. 
	

	
	
		
		

		
		
	


	


_

 

not to single out the above quote, but I have found that when a tweek or component change makes something stand out- it is really a flaw that you are hearing, not an improvement.

 i think the true test of an "improvement" is how long it makes you listen. when you put on a track to listen to a specific lick or secton, and you realize you;ve just listened to the whole dis-- that's an improvement!!!!

 just my 2 cents worth-- no offense intended to anyone-


----------



## K3cT

Quote:


  Originally Posted by *fzman* /img/forum/go_quote.gif 
_not to single out the above quote, but I have found that when a tweek or component change makes something stand out- it is really a flaw that you are hearing, not an improvement.

 i think the true test of an "improvement" is how long it makes you listen. when you put on a track to listen to a specific lick or secton, and you realize you;ve just listened to the whole dis-- that's an improvement!!!!

 just my 2 cents worth-- no offense intended to anyone-_

 

That's... an interesting way to look at the issue. Highly debatable perhaps but illuminating at the same time. 
	

	
	
		
		

		
		
	


	




 For the record, I usually spend several days listening to a certain configuration if I want to evaluate it seriously.


----------



## ROBSCIX

I usually keep a config installed for a week or so but I test with different circuits/devices also.


----------



## ROBSCIX

Has nobody else noticed that TI announced a new opamp to their sound plus line up?


----------



## leeperry

LT1028A is a PRaT killing machine anyway, low end bass is so damn percussive...never heard anything quite like this before


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Has nobody else noticed that TI announced a new opamp to their sound plus line up?_

 

I have 4 x 1641's arriving today 
	

	
	
		
		

		
		
	


	




 Thanks Rob.


----------



## qusp

indeed I have noticed and mine are on their way as well 
	

	
	
		
		

		
		
	


	




; I saw them when I was there getting some reg samples for a dac i'm working on. I dont know that I agree with the tweak standing out being a fault, what if the new component operates at a frequency that is very well suited to the power supply bypassing setup you have installed 
	

	
	
		
		

		
		
	


	




 and just sounds right when you drop it in. ie its suited to the series self resonance of the bypass caps 
	

	
	
		
		

		
		
	


	




 yes i've been reading up on proper bypassing techniques for opamps that operate at high frequency. it seems that the choice of decoupling cap is much more important than even I gave it credit for. in the past I would often simply throw a 1uf electro, 0.01uf and/or 0.1uf COG smd cap at the problem, but because capacitance chances with frequency they really should be thought about very carefully. much of this is more important for HF work, but because many of these opamps we use are designed for that world its probably a good idea to treat them like that. a larger electro cap can be used for decoupling noise in the upper edges of audio band (like switching power supply noise), but not at all suitable for higher up. also I learned a neat trick to make SMD caps perform better; a simple one too, just solder it on its side so the plates arent parallel to the ground plane and traces.

 gotta love the stuff Ti puts out for users of its products, some very valuable information in there. if anyone would like a copy of the PDF that I got this info from let me know. has all manner of very cool circuits for decoupling opamps and generally helping them to perform their best. this particular document is aimed at decoupling opamps used in high frequency ADC applications, but it will transfer pretty well across the board I think; especially for DAC.


----------



## ROBSCIX

Cool some others to compare notes with. I have both the 41 and 42's here now for testing maybe I will slap them on some adapters later to check out. 
 I am interested in building some dual single channel modules. For many opamp families I have tested I usually find I prefer the dual single channel modules over the dual units.

 @gusp, Caps for opamps is a big subject all in itself. Happy reading!


----------



## SpudHarris

Just got home from work and mine are here..... I'm gonna get them on adapters in an hour or so and will report back when I've had a chance to take them in!


----------



## SpudHarris

My initial impressions are that these are indeed very, very fine... I'm gonna leave them in the Fi-Quest for a few days an hope to get a few extended listening sessions, starting tonight. I left the Fi-Quest with 3 channel mode and stacked BUF634's. really nice


----------



## SpudHarris

Double post, god this is slow tonight!!


----------



## ROBSCIX

Great. I have the units now just have to build them!! I have a few new ones I have to build but I have to wait for some new Cardas quad Eucetic solder.


----------



## SpudHarris

Seriously Rob, get them on the adapters already. I'm keen to hear what you think coz I'm loving them. Very transparent, lightning quick very, very nice. Keepers for sure.

 Jeremy when will you get yours?


----------



## ROBSCIX

I am so busy. Just got my single channel ones so I will slap them on some adapters tommorow. I have a nice sounding new circuit to test with so it is all good.


----------



## Mad Max

The Chinese opamp adapters in this thread are nice and all, but they are too tall for my portable amp, and the Browndogs definitely look way too wide but at least seem to be low profile enough.
 Can I sand them down on one side or two so that they may fit? Or can you guys recommend me something just like them but a bit narrower along the sides?


----------



## ROBSCIX

That is the trouble with adapters. You have to fit them into the existing circuit.
 You can sand them down aslong as you don't damage the circuit itself


----------



## 12Bass

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_The Chinese opamp adapters in this thread are nice and all, but they are too tall for my portable amp, and the Browndogs definitely look way too wide but at least seem to be low profile enough.
 Can I sand them down on one side or two so that they may fit? Or can you guys recommend me something just like them but a bit narrower along the sides?_

 

Which BD adapter? Dual SOIC to DIP, or single SOIC to DIP? I haven't found the dual adapters to be much wider than a regular socket. There should be a small amount of space around the edges which can be removed, as long as one takes care not to disturb the traces (or short against a nearby component).


----------



## Pluto2

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_My initial impressions are that these are indeed very, very fine... I'm gonna leave them in the Fi-Quest for a few days an hope to get a few extended listening sessions, starting tonight. I left the Fi-Quest with 3 channel mode and stacked BUF634's. really nice 
	

	
	
		
		

		
			



_

 

Hi Nigel, what do you say on the comparison between opa827 and opa1641 so far? Thanks!


----------



## Mad Max

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Which BD adapter? Dual SOIC to DIP, or single SOIC to DIP? I haven't found the dual adapters to be much wider than a regular socket. There should be a small amount of space around the edges which can be removed, as long as one takes care not to disturb the traces (or short against a nearby component)._

 

The _single_ SOIC-to-DIP. A couple of the traces seem to go a bit too outward, hence why I'm looking for alternatives but low profile ones unlike the DIY Chinese adapters.
 The DIP8 sockets in my portable amp are too close together.

 I'm bugging Practical Devices, see if they'll sell me some of their WhiteCat adapters without opamps. They're the perfect size.

 Again, I'm still open to suggestions.


----------



## qusp

try the ibasso ones, see if they'll sell you some. how many do you need? I might have 2 I can spare; that being said I have sanded /dremeled the browndog doubles back at least 1-1.5mm on each side with no issue


----------



## ROBSCIX

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_The single SOIC-to-DIP. A couple of the traces seem to go a bit too outward, hence why I'm looking for alternatives but low profile ones unlike the DIY Chinese adapters.
 The DIP8 sockets in my portable amp are too close together.

 I'm bugging Practical Devices, see if they'll sell me some of their WhiteCat adapters without opamps. They're the perfect size.

 Again, I'm still open to suggestions._

 

Can you use extension cables as you could move the opamps?
 I think the should be ok provided your not using very high speed opamps.
 Just a suggestion. If I am understanding your issur properly.
 The brown dogs are fairly low.


----------



## Mad Max

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Can you use extension cables as you could move the opamps?
 I think the should be ok provided your not using very high speed opamps.
 Just a suggestion. If I am understanding your issur properly.
 The brown dogs are fairly low._

 

All of my opamps are high-speed, lol.

 iBasso just told me they will be posting their adapters on their website for sale in two weeks. They will be $1.75USD each + expensive airmail shipping, they said.


----------



## slwiser

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_All of my opamps are high-speed, lol.

 iBasso just told me they will be posting their adapters on their website for sale in two weeks. They will be $1.75USD each + expensive airmail shipping, they said._

 

Sounds like a group buy opportunity to me.


----------



## ROBSCIX

What sets these adapters apart from the many others available?


----------



## Currawong

I just bought an Audiovalve RKV Mark II which requires caps on some OPAMPs such as the OPA627 and 637, so I'd be interested in that info about what caps to use, if it's available. I'm also thinking of trying OP27G x2 in it, but don't know enough about what's required to know if I can stick them in without caps or if I need them.

 Also, where are people getting their LME49710HA on adaptors from?


----------



## K3cT

Those metal cans can be soldered straight on DIP8 sockets but need a little care obviously.


----------



## majkel

Check Auzentech for op-amps on adapters.


----------



## Mad Max

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Those metal cans can be soldered straight on DIP8 sockets but need a little care obviously._

 

Or the leads can be bent/trimmed to fit a 2x1 adapter with sockets, right?

 iBasso tells me it is $22USD shipping via UPS, DHL, or EMS, or "air mail" (HK Post?) for just $4-5USD.
 Given the situation with the airlines in China, the cheaper method may take up to a month to reach you. Meh.


----------



## K3cT

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_Or the leads can be bent/trimmed to fit a 2x1 adapter with sockets, right?

 iBasso tells me it is $22USD shipping via UPS, DHL, or EMS, or "air mail" (HK Post?) for just $4-5USD.
 Given the situation with the airlines in China, the cheaper method may take up to a month to reach you. Meh._

 

Yeah. Just take care of the pin-outs. I never knew iBasso makes op-amp adapters now. Do they have special features?


----------



## SpudHarris

I have only ever used these for TO99 OpAmps. Brown Dogs in general seem to be a little flimsy I think but to be truthfull you don't real handle stuff like this with force so it's never been an issue.

 @ Currawong - Is the OP27G a killer OpAmp? I've not heard much about it.....but always looking.


----------



## K3cT

Nigel, how did the 797Bs do with you? I'm not sure what is happening but I keep coming back to those particular op-amps despite having newer toys to play with.


----------



## SpudHarris

Haha, I am exactly the same. I got some OPA1641's recently and they are indeed fine, I left them in for about a week before going back to the AD797BRZ's. Don't know if it's placebo but the BRZ's do seem a little fuller than the ARZ's, they cost twice the amount so there must be something different right?

 Anyhow I back with them now and they are just fantastic in everyway.


----------



## leeperry

I still think that LT1363 is my all time winner...it just seems to do everything exactly the way I want to hear it 
	

	
	
		
		

		
		
	


	




 LT recommend it as a top choice for audio and many top units are using it, it simply outputs a very balanced uncolored sound...SS is very natural and versatile! and its slew rate is so fast that it can catch every tiny bit of "low level detail"(it'd make Patrick82 proud 
	

	
	
		
		

		
		
	


	




)

 more often than not, you can almost hear the room reverb of the studio cabin where the vocals were recorded...talk about analytical sound, huh! I have yet to hear an OPA-sumthing that can top it.


----------



## Currawong

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_@ Currawong - Is the OP27G a killer OpAmp? I've not heard much about it.....but always looking._

 

I found it to have excellent mids. I came across them in my local electronics store. I'm not sure why particularly the G version is available here. I was happy to find it as it was cheaper than the 627 but without the top-end roll-off. The closest-sounding thing to it would be the Sun HDAM, if it's not quite as resolving.


----------



## Mad Max




----------



## majkel

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_more often than not, you can almost hear the room reverb of the studio cabin where the vocals were recorded...talk about analytical sound, huh! I have yet to hear an OPA-sumthing that can top it._

 

OPA228P with the offset pin trick. I am sorry to communicate it's sound is closest to what I hear when connect directly to the outputs of the CS4397 DAC. It always sounded right to me, all other op-amps I know limit either source imaging or the whole soundstage. In the OPA228 series the soundstage is unlimited in all directions and sound sources melt in the soundstage giving impression of being huge but it is exactly what you hear when closing your eyes and listening to the sounds of ambience. Most op-amps artificially shrink sources or draw soundstage as a shape. AD797BRZ makes it wide but short in the X Axis. In the LT1028A it's better with the soundstage but worse with instrument imaging. The tone also seems more correct on the LT. LT1363 is obviously colored, especially in treble range, the LT1028 is far more neutral. However, I'm happy I could get rid of the op-amp stage and connect to the DAC directly without loading it above recommended specs. I'll give the OPA228P one more try some day to see if it's stable at this low gain of around two without capacitors in the feedback loops just to be sure it's the op-amp what's the bottleneck and try once more other unity gain stable op-amps without them. I am not expecting a significant change in the impressions as passively low pass filtered DAC outputs preserve all original sonic qualities just having attenuated highs.


----------



## K3cT

For me the LT0128A is very musical and yet remains transparent. It also does vocals very well. However, the LT1028A can sound a bit warmish and sluggish compared to the AD797B. 

 The AD797B is not as musical in comparison but it's speedier, leaner and has better imaging. Soundstage is very wide, even wider than the OPA Moon which complements my HF2 very well. 

 Just FYI, these op-amps are used as drivers in my amplifier and biased to class A and decoupled with 0.1uF film caps.


----------



## leeperry

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_OPA228P with the offset pin trick. I am sorry to communicate it's sound is closest to what I hear when connect directly to the outputs of the CS4397 DAC. It always sounded right to me, all other op-amps I know limit either source imaging or the whole soundstage. In the OPA228 series the soundstage is unlimited in all directions and sound sources melt in the soundstage giving impression of being huge but it is exactly what you hear when closing your eyes and listening to the sounds of ambience. Most op-amps artificially shrink sources or draw soundstage as a shape. AD797BRZ makes it wide but short in the X Axis. In the LT1028A it's better with the soundstage but worse with instrument imaging. The tone also seems more correct on the LT. LT1363 is obviously colored, especially in treble range, the LT1028 is far more neutral. However, I'm happy I could get rid of the op-amp stage and connect to the DAC directly without loading it above recommended specs. I'll give the OPA228P one more try some day to see if it's stable at this low gain of around two without capacitors in the feedback loops just to be sure it's the op-amp what's the bottleneck and try once more other unity gain stable op-amps without them. I am not expecting a significant change in the impressions as passively low pass filtered DAC outputs preserve all original sonic qualities just having attenuated highs._

 

I'm not sure whether it's a nocebo(I really hate the OPA/LME series, they're just time wasters to me 
	

	
	
		
		

		
		
	


	




), or my soundcard design...but OPA228P didn't do it for me, but well my soundcard requires unity gain stable op-amps...and LT1028A clearly isn't! and AD797B isn't either.

 I've got some LT1128AC on order, this might be a nice option 
	

	
	
		
		

		
		
	


	




 the LT chips just sound really really good to me, I really see no point whatsoever bothering w/ LME4972x/OPA parts at this point...1363 isn't perfect, but it makes you nod your head silly, SS is very natural...and its slew rate is so damn fast that it can render minute details.

 sure, the burson etc etc can give a more euphonic sound, but they are not as "detailed"...a distorted colored sound can be appealing(as the 1028A likes to give me), but it's highly colored and not uber-detailed.

 I'm repeating myself but I have yet to listen to an op-amp that allows me to hear so clearly the studio cabin walls reverb...this is nuts! this is almost TOO realistic, but so far so good 
	

	
	
		
		

		
		
	


	




 and the bass has always been very good on the 1363, so I don't need to use a final buffer...I can see why LT thinks it's one of their top chips for audio, it just does it really really well!
  Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_For me the LT0128A is very musical and yet remains transparent. It also does vocals very well. However, the LT1028A can sound a bit warmish and sluggish compared to the AD797B. 

 The AD797B is not as musical in comparison but it's speedier, leaner and has better imaging._

 

I would agree w/ these 2 descriptions, 1363 is a nice in-between compromise to me...it kills both in the details department(and not 4562'ish like 
	

	
	
		
		

		
		
	


	




)


----------



## majkel

Some clarifications. I was talking about the Z axis (vertical) of the AD797B's soundstage. The depth and the width are very good. 

 Yes, I agree, the OPA228P is a hog in terms of stability so it might be useless in many applications. 

 Regarding LT1028 - it accepts unity gains when the impedance of the source is above 500 ohms. It's easily achieved wherever coupling via resistors happens. LT1128 sounds like an ass.

 I agree with the LT1363 having good PRaT, fun and punch. Its sound colors are likeable too.


----------



## leeperry

I think 1363 is clearer than 797B on the X axis, but kinda fails in the Z department...797B was just more impressive there! ah well, no free lunch as usual, and maybe I care more about X than Z duh


----------



## K3cT

This LT1363 is simply the single-channel version of the LT1364 yes?


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Some clarifications. I was talking about the Z axis (vertical) of the AD797B's soundstage. The depth and the width are very good. 

 Yes, I agree, the OPA228P is a hog in terms of stability so it might be useless in many applications. 

 Regarding LT1028 - it accepts unity gains when the impedance of the source is above 500 ohms. It's easily achieved wherever coupling via resistors happens. LT1128 sounds like an ass.

 I agree with the LT1363 having good PRaT, fun and punch. Its sound colors are likeable too._

 

What are you thoughts on decoupling?


----------



## majkel

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_What are you thoughts on decoupling?_

 

Op-amps are sensitive to it, as well as to quality of the PSU.


----------



## 12Bass

All your base are belong to OPA1641.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_All your base are belong to OPA1641._

 

LOL, found those did you?


----------



## leeperry

hehe, sometimes I miss the AD797B Z soundstage and the 1028A crazy low end bass..but they clearly couldn't compete on vocals and general transparency IMHO, apparently a very high slew rate is where the money is.

 You could almost ID microphones and the kind of dampening material they put on the studio cabin walls w/ the 1363 hahaha..I'll try to add two 1360/1128 as final buffer for the hell of it.


----------



## dasmb

Hey ya'll chip-heads got any advice on drop-in 8-DIP upgrades?

 I'm running a CMOY -- actually, two of them, one with an OPA 134 and the other with a OPA 227, which I slightly prefer. I'm interested in experimenting with the sound of different chips prior to building my next amp (which will likely be buffered, 3 channel, the whole 9). I could be convinced to try an SOIC on an adapter, but the concept sounds less durable to me.

 Supply voltage can be either 9V or 18V. Gain is 2.

 I'm looking to order at a bare minimum a Linear Technologies LT1364CN8, but $6 shipping on a $7 order seems silly. If I could get between 3 and 5 interesting variants from Digikey all at once that would be the cat's PJs, man.


----------



## leeperry

If I were you I'd go 2*1363 on an adapter(wider center channel)..dual opamps always shrink the stereo image IME, but well YMMV 
	

	
	
		
		

		
			





 only on the OPA1612, they say that they finally used two different pieces of waffer to avoid killing the xtalk altogether....but most dual opamps just got way too much in common on the two channels to my taste, even Browdog says it...and majkel agrees on that too I think.

 comparing 1364 <> 2*1363, it's dead obvious....I see it as unbalanced/balanced.


----------



## Pluto2

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_All your base are belong to OPA1641._

 

Is it that good!? 
	

	
	
		
		

		
		
	


	




 How does it compare to opa221/827 from your impression?

 Oh, I got mine too, need to get more header pins to solder them up for testing....


----------



## 12Bass

Sorry... haven't received any yet.... just having a bit of fun. Forgot the mention that the OPA1612, in certain applications, can cause the sweet, resonant, oscillation of cosmic strings....


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Sorry... haven't received any yet.... just having a bit of fun. Forgot the mention that the OPA1612, in certain applications, can cause the sweet, resonant, oscillation of cosmic strings....




_

 

I figured you tried them out based on what you said. They are new addition to the sound plus line up from TI. The 1642 which is dual and the 1641 which is single. I mentioned the release to a few guys through PM.
 They sound good to me and spud also said they sound good based on testing. I would be interested in hearing your opinion when they come in.


----------



## ROBSCIX

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Is it that good!? 
	

	
	
		
		

		
		
	


	




 How does it compare to opa221/827 from your impression?

 Oh, I got mine too, need to get more header pins to solder them up for testing....
	

	
	
		
		

		
		
	


	


_

 

They are quite good based on the limited testing I have had a chance to perform. They are a very new opamps from TI but reports from other members here also say they are very good. 
 You will only know if you test them yourself as everybody is using different circuits.


----------



## K3cT

Speaking of audio-specific op-amps, Linear also has their own LT1115. Anyone tried that before?


----------



## leeperry

I did try LT1115CN8, it was nothing to write home about...Andrea said it'd sound "sweeter" thank 1028A, I'd say "duller".

 BTW, I read several times that chinese music was the worst benchmark for audio gear...and I have to admit that the remastered edition of the "Enter The Dragon" OST sounds miles better on the 1363 that it ever did on the 797B.

 they use far more complicated harmonies that western music I think...now I need to find a matching final buffer, maybe 1128A


----------



## ROBSCIX

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Speaking of audio-specific op-amps, Linear also has their own LT1115. Anyone tried that before?_

 

Order one up and try it out. Applicaiton and circuit plays a very large role in overall sound quality.


----------



## leeperry

ah well, I'm back on the 797B...it's hard to pass on an opamp that throws audio at you on the X and Y axis simultaneously!

 apparently I managed to kill 2x797B and 2x1028A, not sure how?! static electricity maybe? they just give a loud whine, it sounds like what you get on a FM radio between 2 stations 
	

	
	
		
		

		
		
	


	




 anyway, 797B on a DAC output has always left me out of speech....w/ its amazing SS! sure, you can't hear the studio cabin walls reverb, but who cares about that anyway? 
	

	
	
		
		

		
		
	


	




 I'll add some brand new 1028A as final buffer later today, for the "coup de grace"


----------



## K3cT

Told you the 797B is where the gold is at, leeperry. 
	

	
	
		
		

		
		
	


	




 OK, now it's time to put these 4627-1s on a serious audition.


----------



## leeperry

well 4*797B+2*1028A has always been my fav combo by far...but some of those chips were giving a loud shredding whine?! I thought they were oscillating to death...but these were just KIA, some other chips from the same batch work just fine 
	

	
	
		
		

		
		
	


	




 so far 797B just works on the DAC output, no crackles, no whine...just an outstanding SQ.

 I hope 1028A will play nice as final buffer, it gives such an amazing low end bass slam...I can't find a word to describe how awesome it sounds.


----------



## ROBSCIX

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Told you the 797B is where the gold is at, leeperry. 
	

	
	
		
		

		
		
	


	




 OK, now it's time to put these 4627-1s on a serious audition._

 

There are quite a few around that have been advocating the AD797 and the 4627-1's they seem to be very popular among the opamps swappers.


----------



## SpudHarris

Well I have most if not all the must haves including the ADA4627-1's, OPA1641's and I always seem to come back to the AD797's.....

 The OPA1641's are a close second though, they are very nice. Detailed & musical but lacking slightly in comparison to the AD797's. I have found that most opamps that offer up the kind of detail that the 797's do tend to be sterile by nature, this is where the 797's win IMO because somehow they still remain involving, musical and unfatiguing.

 I'm listening now with the Fi-Quest in 3 channel mode with 2 x 2 stacked Buf634's and the AD797BRZ's in L/R and man I get shivers......


----------



## leeperry

ah well, I've tried two pairs of 1028ACN8(one was brand new) and one pair of 1028CS8 as final buffer....either they work for 10 mins then start giving a very loud PSHHHHHHHHSSSHHH sound on the left channel, or the left channel doesn't work at all and does slight static for time to time...very strange, as it used to work fine before?! if I put back the stock OPA2604, everything's fine of course..so the damn card is still working(poor little thing 
	

	
	
		
		

		
			





)

 I understand that it's meant for gain <1...but why did it work fine for several weeks?? anyway, 797B works on the DAC output, it's all that matters to me 
	

	
	
		
		

		
		
	


	




 maybe it's time to try OPA211 as final buffer...it's a damn shame as I was really enjoying 1028, my hopes are rather high for 1128


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well I have most if not all the must haves including the ADA4627-1's, OPA1641's and I always seem to come back to the AD797's.....

 The OPA1641's are a close second though, they are very nice. Detailed & musical but lacking slightly in comparison to the AD797's. I have found that most opamps that offer up the kind of detail that the 797's do tend to be sterile by nature, this is where the 797's win IMO because somehow they still remain involving, musical and unfatiguing.

 I'm listening now with the Fi-Quest in 3 channel mode with 2 x 2 stacked Buf634's and the AD797BRZ's in L/R and man I get shivers......_

 

ah, my buf634's!? you just reminded me. I have to build some of them.


----------



## diditmyself

Like I've said several times before, LT1028 is not an opamp to just drop into any circuit. It needs proper compensation. (It's the same with AD797 - proper compensation and "right" resistor values).

 Before and after pics:

The best sounding audio integrated opamps - Page 123 - diyAudio

 An example of a functioning circuit:

Cmoy headphone amp? - Page 2 - diyAudio


----------



## leeperry

yes, that's too bad for me...but why did it work fine for several weeks before going PSCHHHHHHHHH on me(feedback loop?), baffles me 
	

	
	
		
		

		
		
	


	




 a friend of mine currently runs ACN8 on the same exact board as mine, I'm kinda jealous..

 1128 should play nice hopefully? 797 works perfectly fine(for now 
	

	
	
		
		

		
		
	


	




) and if it stops working, I'll get a new soundcard


----------



## majkel

Do something to have a 510 ohms resistor in series with In+ of the LT1028 and it's done. No changes to the feedback loop are needed.


----------



## leeperry

well I got the 1028A on a browndog, could I just solder 2 resistors on it...and call it a day? 
	

	
	
		
		

		
		
	


	




 I dearly hope 797B won't turn nuts anytime soon, as 1028A used to work fine...maybe its oscillation weakened/killed something on the board


----------



## ROBSCIX

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_Like I've said several times before, LT1028 is not an opamp to just drop into any circuit. It needs proper compensation. (It's the same with AD797 - proper compensation and "right" resistor values).

 Before and after pics:

The best sounding audio integrated opamps - Page 123 - diyAudio

 An example of a functioning circuit:

Cmoy headphone amp? - Page 2 - diyAudio_

 

Sure, but some are notorious for wanting to learn things the hard way.


----------



## majkel

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well I got the 1028A on a browndog, could I just solder 2 resistors on it...and call it a day? 
	

	
	
		
		

		
		
	


	


_

 

Just try lifting pin 3 to insert one wire of the resistor instead, and the other one connect (solder) to the lifted pin. This way you will have the resistor in series with the non-inverting input.


----------



## leeperry

ok thanks for your help, majkel..I'll look into it!

 but now that I remember it, I sent 2*LT1028CS8 and 2*LT1363CS8 on browndogs to a friend that has an X-Fi Forte 7.1(stock was a 4562NA) and the 1028 didn't output any audio at all...Andrea sold it to me as the 8th world wonder(which it can be!) but it's definitely not a drop-in replacement for anything(as diditmyself pointed out several times).

 I spoke to Scott Wurcer and he told me that getting the 797 to work unity gain stable wouldn't be too hard...and luckily it does work on the DAC output of my HD2 
	

	
	
		
		

		
		
	


	




 but strangely, I've tried 4*AD797BN directly soldered on browndogs, and 4 others w/ browndogs + high quality sockets soldered on top....and the socketed 797B sounded so much better?!?! wider SS, clearer sound and more percussive low end bass, maybe the sockets add capacitance or whatever


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Just try lifting pin 3 to insert one wire of the resistor instead, and the other one connect (solder) to the lifted pin. This way you will have the resistor in series with the non-inverting input._

 

I have asked a few in this thread about a subject and wanted to get your perspective on it also. What is your opinion or thoughts on using bypassing Caps on opamp modules? Some here use them religiously and others don't bother. What is your thoughts on it?


----------



## leeperry

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Just try lifting pin 3 to insert one wire of the resistor instead, and the other one connect (solder) to the lifted pin. This way you will have the resistor in series with the non-inverting input._

 

so to be perfectly clear...I should lift pin3 of each LT1028 from the browndog, solder it to one end of a 510Ω resistor such as these ones: http://i8.ebayimg.com/01/i/001/46/06/6761_12.JPG

 solder the other end of the resistor to the socket's pin3, do it on both 1028...fire it up, and no more oscillation? 
	

	
	
		
		

		
		
	


	




 why did it work for weeks before oscillating to death is one thing I fail to understand...op-amps sure have magic to them(like the fact that they sound better on additional sockets than when directly soldered to the browndogs 
	

	
	
		
		

		
		
	


	




)


----------



## diditmyself

LME49990 - Ultra-low Distortion, Ultra-low Noise Operational Amplifier


----------



## majkel

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I have asked a few in this thread about a subject and wanted to get your perspective on it also. What is your opinion or thoughts on using bypassing Caps on opamp modules? Some here use them religiously and others don't bother. What is your thoughts on it?_

 

If the caps used on the adapter are good for audio, then they help. Otherwise, when you have some decent capacitors on board. Better remove them. That was the case with Audio-gd HDAMs. I noticed improvement after removing the Evox Rifa MMK add-ons. 
  Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_so to be perfectly clear...I should lift pin3 of each LT1028 from the browndog, solder it to one end of a 510Ω resistor such as these ones: http://i8.ebayimg.com/01/i/001/46/06/6761_12.JPG_

 

Yes, each pin of each LT1028. The resistance might be a bit bigger, it will work, too.  Quote:


 solder the other end of the resistor to the socket's pin3, do it on both 1028...fire it up, and no more oscillation? 
	

	
	
		
		

		
		
	


	



 

I can't promise that.


----------



## 12Bass

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_LME49990 - Ultra-low Distortion, Ultra-low Noise Operational Amplifier_

 

Wow... interesting... a whole lotta "ultra" there...


----------



## leeperry

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Yes, each pin of each LT1028. The resistance might be a bit bigger, it will work, too. I can't promise that. 
	

	
	
		
		

		
			



_

 

alright! I'll try to see if I can't find smaller resistors as these ones look rather big 
	

	
	
		
		

		
		
	


	




 OTOH, I also like the 4*AD797B on the AK4396 output w/o a final buffer, its amazing SS is not colored by another chip...I'll report back! 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Wow... interesting... a whole lotta "ultra" there... 
	

	
	
		
		

		
		
	


	


_

 

as in "ultra" ear-splitting? 
	

	
	
		
		

		
		
	


	




 49722MA was quite unbearable..I can foresee a LME49999 w/ 0% THD


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_If the caps used on the adapter are good for audio, then they help. Otherwise, when you have some decent capacitors on board. Better remove them. That was the case with Audio-gd HDAMs. I noticed improvement after removing the Evox Rifa MMK add-ons. _

 

Yes, we had talked about this before and you said remove them.
 I would check the circuit first, I was just considering adding some bypass caps to a couple modules to test with and without. To see/rather hear if they help at all. Some of the guys I have talked with seem to use them on every opamp module they build. Just considering some ways to improve modules.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Wow... interesting... a whole lotta "ultra" there... 
	

	
	
		
		

		
		
	


	


_

 

Very interesting. Will have to try those out.


----------



## K3cT

Initial impressions on the 4627-1: This is a very meaty sounding op-amp! It's probably as detailed as the AD797B but doesn't have the latter's sense of airiness.


----------



## SpudHarris

K3cT - Agreed, the 4627 is very detailed and in my Fi-Quest it is very full sounding. It's nice but I bet you go back to the AD797's 
	

	
	
		
		

		
		
	


	




 The nearest I've come to a successor to the 797 is the OPA1641, have you got around to trying it yet?


----------



## diditmyself

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_so to be perfectly clear...I should lift pin3 of each LT1028 from the browndog, solder it to one end of a 510Ω resistor such as these ones: http://i8.ebayimg.com/01/i/001/46/06/6761_12.JPG

 solder the other end of the resistor to the socket's pin3, do it on both 1028...fire it up, and no more oscillation? 
	

	
	
		
		

		
		
	


	




 why did it work for weeks before oscillating to death is one thing I fail to understand...op-amps sure have magic to them(like the fact that they sound better on additional sockets than when directly soldered to the browndogs 
	

	
	
		
		

		
		
	


	




)_

 

If the buffer amp in your soundcard is run at unity gain, you'll have a hard time to get LT1028 stable. I tried it unity gain yesterday, and I could get it to oscillate in 100 different ways.

 Do you know what your circuit looks like? Input and output resistors, feedback cap or resistor etc.


----------



## majkel

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_49722MA was quite unbearable..I can foresee a LME49999 w/ 0% THD 
	

	
	
		
		

		
		
	


	


_

 

x2. There is also LME50000 in the development stage with THD+N down to -0,1% which means ability to clean out the signal from distortions and noise. :]


----------



## leeperry

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_If the buffer amp in your soundcard is run at unity gain, you'll have a hard time to get LT1028 stable. I tried it unity gain yesterday, and I could get it to oscillate in 100 different ways.

 Do you know what your circuit looks like? Input and output resistors, feedback cap or resistor etc._

 

oh ok, what annoys the hell out of me is that it worked perfectly fine for several weeks...and a friend of mine is using it as we speak, my soundcard works fine w/ any other opamp...I'm tempted to sell it and get a brand new card, use 4*797B+2*1028A(they sound eye popping together!) and call it a day 
	

	
	
		
		

		
		
	


	




 but if it did kill/weaken some caps on my card in the long run, it will occur again in the future..and an oscillating 1028 sounds VERY angry 
	

	
	
		
		

		
		
	


	




 that's what Slash47 told me:
  Quote:


 You can't use not unity gain stable opamps on the HD2, the gain is too low. LT1028, AD797, OPA(2)228, OPA637 etc all don't work or oscillate. The only one's that're stable and I don't know if they're unity gain are AD8022 and AD8397.

 It's a voltage out DAC chip (AK4396) so the opamps have a gain of just 1 to supply current and make it single ended. The layout isn't designed to make a gain of 1 good enough for something like the LT1028 and it's never gonna work for uncompensated BB's 
 

 Quote:


 Check out page 35 of this if you want to know how the opamps are configured on the HD2:
http://www.asahi-kasei.co.jp/akm/en/...k4396_f00e.pdf

 Basically the first two just add drive (and thus dynamics) to the signal and the second one sums the plus and minus for unbalanced out. (That is very much in layman's terms, for the technicalities you can read the data sheet in the link.) 

 The DC supply voltage for the opamps is approximately +/-9V, or more precisely +/- 8.8V on my HD2 card. That is, 17.6V across pin 4 and 8.


----------



## majkel

AD797 is unity gain stable. LT1028 is unity gain stable when the source has at least 500 ohms of output impedance. See datasheets for details. I could use LT1028 in unity gain this way in a circuit it had oscillated before.


----------



## leeperry

ok, so that would explain...797 works fine on the DAC output, but oscillates just like 1028 as final buffer now(it does a loud white noise on the left channel only)...it used to work fine! I think I've screwed something up on the card...it works fine w/ the stock OPA2604, though...so I think I will sell it and get a brand new card.

 I think problems started on the final buffer after I rolled 2*LT1677...anyway I've rolled zillions of opamps on this board, talk about begging for troubles 
	

	
	
		
		

		
		
	


	




 this guy sells AD797B ready to roll, I might fancy that as well(a friend of mine bought some from this seller and loooooves them, of course 
	

	
	
		
		

		
		
	


	




): Dual to Mono Op amp module AD797BR - eBay


----------



## qusp

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Yes, we had talked about this before and you said remove them.
 I would check the circuit first, I was just considering adding some bypass caps to a couple modules to test with and without. To see/rather hear if they help at all. Some of the guys I have talked with seem to use them on every opamp module they build. Just considering some ways to improve modules._

 

I use it primarily on chips that are very sensitive to noise as in ultra low noise (AD797 for example). but mainly if the chips are not decoupled well. many of the amps I am using the adapters in are socketed for swapping opamps, so to allow for a wider variety of chips there really isnt much in the way of specific decoupling. so by adding tailored caps for each chip I get the performance I want.

 that national chip does indeed look interesting


----------



## K3cT

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_K3cT - Agreed, the 4627 is very detailed and in my Fi-Quest it is very full sounding. It's nice but I bet you go back to the AD797's 
	

	
	
		
		

		
		
	


	




 The nearest I've come to a successor to the 797 is the OPA1641, have you got around to trying it yet?_

 

I think this has potential so I'm going to leave it running for a couple of days. I cheat a bit by using the AD797B in the ground channel though. 
	

	
	
		
		

		
		
	


	




 The OPA1641 is definitely interesting. Thanks for the reminder, I'll order them soon. My LME49710 metal can should arrive any day now, what do you think of them?


----------



## Leny

A quick side post. I've not read the whole thread so apologies if this has been said before...

 Was just lurking about on diyaudio.com and the designer of the 797 hangs out there; his name is Scott Wurcer. You might be able to pick up some tips by searching through their threads?


----------



## ROBSCIX

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_I use it primarily on chips that are very sensitive to noise as in ultra low noise (AD797 for example). but mainly if the chips are not decoupled well. many of the amps I am using the adapters in are socketed for swapping opamps, so to allow for a wider variety of chips there really isnt much in the way of specific decoupling. so by adding tailored caps for each chip I get the performance I want.

 that national chip does indeed look interesting_

 

Ah, looks like there is more testing for me to do.
 I gotta go and build some units. You just reminded me.


----------



## SpudHarris

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_I think this has potential so I'm going to leave it running for a couple of days. I cheat a bit by using the AD797B in the ground channel though. 
	

	
	
		
		

		
		
	


	




 The OPA1641 is definitely interesting. Thanks for the reminder, I'll order them soon. My LME49710 metal can should arrive any day now, what do you think of them?_

 

Yeah, I liked the 797's in ground on my P3+ they seemed to enhance almost anything I put in L/R.

 I love the metal can 49710's also but it's been a while since I've used them....


----------



## dex85

hey guys, if you had to pick one (or more) op-amps that get it tonally right, which one would you choose? i know it's not black and white and there are other things factoring in, like headphones etc. still, i'm interested in people's opinions on this.


----------



## ROBSCIX

What do you consider tonally "right"? That is the trouble, people have very different opinions on what is right or sounds wrong. Not to mention most consider a really good opamp to be tonally "transparent" in that it doesn't add any of it's own color to the signal it just amplifies it. Tricky question...


----------



## dex85

by tonally right i meant that instruments' timbre is as close as possible to the real life; so piano sounds like piano and not octave higher. neutral, tonally transparent, etc... possibly in whole audioband, not just in midrange or highs.

 i understand it's a tricky question since there are so many speakers/headphones that add its unique coloration.


----------



## leeperry

humm the 4*AD797B on the DAC output don't give any white noise or whatever...but sometimes in fade outs at the end of songs, they give slight audible distortion.

 I'm getting sick and tired of blind rolling tbh 
	

	
	
		
		

		
			





 I've asked for a quote to get this w/ AD797BR instead of AR 
	

	
	
		
		

		
		
	


	




HLLY HIGH END DMK-IV DAC USB Headphone AMP - eBay

 it does 24/96 over USB, perfect! I even see an empty DIP8 socket, maybe I could sneakily put some LT1028A in there too....putting a DAC stage within a computer case on a SMPS is a disgrace anyway 
	

	
	
		
		

		
		
	


	




*EDIT:* they'll switch the AR for BR for $10...interesting!


----------



## K3cT

Quote:


  Originally Posted by *dex85* /img/forum/go_quote.gif 
_by tonally right i meant that instruments' timbre is as close as possible to the real life; so piano sounds like piano and not octave higher. neutral, tonally transparent, etc... possibly in whole audioband, not just in midrange or highs.

 i understand it's a tricky question since there are so many speakers/headphones that add its unique coloration._

 

The LT1028 has got great timbre and so does the AD797. The former is more musical and colored than the latter though.


----------



## dex85

AD797 seems to be popular around here. can't wait to try it, i'm waiting on Auzentech to start selling them since i need two of them on adapter. hopefully it will be stable in my setup.


----------



## Mad Max

How can one do away withe the LME49710's plasticky tone and "rolled-up" highs?
 Yes, besides swapping them out for another pair of opamps, lol.


----------



## Mad Max

..


----------



## dex85

LME49720 have similar problems, i reduced it with reverse sounding op-amp in the buffer, but your unit use different configuration i believe (Compass, right?). maybe EQ if your source is a PC, not many options left besides swapping, you can't change them for what they are


----------



## leeperry

Quote:


  Originally Posted by *dex85* /img/forum/go_quote.gif 
_AD797 seems to be popular around here. can't wait to try it, i'm waiting on Auzentech to start selling them since i need two of them on adapter. hopefully it will be stable in my setup._

 

they're selling AD797A, you want B!!!
  Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_How can one do away withe the LME49710's plasticky tone and "rolled-up" highs?_

 

you will learn to hate the LME497xx serie 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *Leny* /img/forum/go_quote.gif 
_A quick side post. I've not read the whole thread so apologies if this has been said before...

 Was just lurking about on diyaudio.com and the designer of the 797 hangs out there; his name is Scott Wurcer. You might be able to pick up some tips by searching through their threads?_

 

hehe, Scott is the god of opamps basically 
	

	
	
		
		

		
		
	


	




 when you'll hear 797B, you'll see exactly what I mean!

 anyhow, I'm getting a brand new HD2(been rolling every opamp in the book for the past 6 months, maybe something's ruined by now, OTOH OPA2132P/LT1364 work damn fine!)...and if it still cr*ps out...Scott has given me some snubber tricks to make AD797B play nice, together w/ the snubber trick majkel gave me for the 1028A...I will go to an audio repair shop and ask the guy to get them STABLE, whatever it takes


----------



## ROBSCIX

Quote:


  Originally Posted by *dex85* /img/forum/go_quote.gif 
_LME49720 have similar problems, i reduced it with reverse sounding op-amp in the buffer, but your unit use different configuration i believe (Compass, right?). maybe EQ if your source is a PC, not many options left besides swapping, you can't change them for what they are 
	

	
	
		
		

		
		
	


	


_

 

See what I mean, people cannot even agree what opamp sounds good never mind which sounds right. The surrounding circuit will have some influence on the overall sound of the output.


----------



## LingLing1337

I'm about to roll some LME49720NA/LM4562NA into sockets where TL082CN were formerly present... can anyone see a problem with this? How about the AD797B(RZ)?


----------



## ROBSCIX

It is hard to say without knowing exactly how the circuit is set up. Try it out and hope for the best. You do understand that National Semi, suggests the LME49720NA and the LM4562NA are the exact same chips aside from the paint right?
 That being said, I have heard quite a few people suggest they hear differences between the two chips.
 Post your impressions when your done.


----------



## dex85

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_they're selling AD797A, you want B!!!_

 

what's the sonic difference between A and B version? or is there other reason i should pick up the latter?


----------



## LingLing1337

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_It is hard to say without knowing exactly how the circuit is set up. Try it out and hope for the best. You do understand that National Semi, suggests the LME49720NA and the LM4562NA are the exact same chips aside from the paint right?
 That being said, I have heard quite a few people suggest they hear differences between the two chips.
 Post your impressions when your done._

 

Yup, I included both names just to make sure everyone knows what chip I'm talking about... I do have both though. 

 I have to desolder the stock opamps in my Decco and put in sockets. Any tips for desoldering? (I only have braid.)


----------



## ROBSCIX

Quote:


  Originally Posted by *LingLing1337* /img/forum/go_quote.gif 
_Yup, I included both names just to make sure everyone knows what chip I'm talking about... I do have both though. 

 I have to desolder the stock opamps in my Decco and put in sockets. Any tips for desoldering? (I only have braid.)_

 

The braid should work fine. Just watch you don't pull up the pads.

 The socket idea is the way I would go also. Makes more sense. Just ensure you use high grade sockets.
 Machined sockets will gold plating should be good!
 Pressed are the cheap ones you can notice the difference because machined have the round pin holes and the
 pressed units have a slot.


----------



## ROBSCIX

Double post ignore.


----------



## Mad Max

Quote:


  Originally Posted by *dex85* /img/forum/go_quote.gif 
_LME49720 have similar problems, i reduced it with reverse sounding op-amp in the buffer, but your unit use different configuration i believe (Compass, right?). maybe EQ if your source is a PC, not many options left besides swapping, you can't change them for what they are 
	

	
	
		
		

		
			



_

 

My Compass and Minibox-E+ are my opamp-rollable gear. I roll opamps most in my portable amp, in my dac I just stick to the Earth or Sun HDAM. I may put opamps in the dac when I use its line-out to feed the portable amp in order to see what kind of sound I get from combining them. Also, well, my portable amp isn't quite as forgiving as my dac's built-in headamp.

 Also, I do not see people voicing the same complaints about the LD MKV and DAC_I/II or Keces gear, and they use the LME opamps, so they must be doing something right I imagine. And what opamp has the opposite sound? That doesn't sound simple. If it were like the LME having a "yellow" sound, then the opposite should be something with a "blue" sound. But the opposite of "plastic"? "Metallic"?


  Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_...
 you will learn to hate the LME497xx serie 
	

	
	
		
		

		
		
	


	



 ..._

 

So they all sound similar to the 49710? =\
 Eww, lol.

 Edit: And then when I place the LME's in my portable amp, it has a "grey" sonic color instead with fatiguing highs and mids that overtake the highs and lows. I'm not sure how to continue describing them, it's a really weird and most unpleasant sound.


----------



## dex85

by opposite sounding i meant op-amps with warmer and more balanced character. using the SineGen it was kinda funny to hear the roller-coaster FR of the 49720. very unbalanced, at least with my gear. but same op-amps may act differently in various circuitries like Robscix said, so who knows.


----------



## diditmyself

If you use LME497xx at low gain settings, I've found it's peaking. You have to use appropriate compensation caps. Furthermore it's more sensitive to interference than most opamps, and an input filter might be good idea. If properly implemented, I think it's quite neutral. I think it's a good opamp for the price, better than most, but there are more "musical" opamps to be found.


----------



## leeperry

Quote:


  Originally Posted by *dex85* /img/forum/go_quote.gif 
_what's the sonic difference between A and B version? or is there other reason i should pick up the latter?_

 

http://www.head-fi.org/forums/f6/aud...-v-2-a-397691/

 I've only heard B, but why bother w/ lower grade chips? when you compare OPA2132 to 2134, you get to understand this very quickly!
  Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_So they all sound similar to the 49710? =\
 Eww, lol._

 

the only things I've heard from the 497xxNA/MA chips were :
 -very wide and artificial dull SS
 -agressive trebles
 -inexistent low end bass percussion(for this, nothing beats the LT1028A IME)

 49720HA had a much deeper bass, but the trebles seemed to suffer.
  Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_If you use LME497xx at low gain settings, I've found it's peaking. You have to use appropriate compensation caps. Furthermore it's more sensitive to interference than most opamps, and an input filter might be good idea. If properly implemented, I think it's quite neutral. I think it's a good opamp for the price, better than most, but there are more "musical" opamps to be found._

 

yes, rolling opamps is very dumb...hoping that an opamp will give its best w/o major circuit modifications is like believing that Jesus will come back anytime soon.

 companies put sockets to make the wannabes happy, but the pros(on diyaudio.com for instance) know that rolling opamps is just aimed at brainless ppl 
	

	
	
		
		

		
		
	


	




 two links explaining all this:
Tweaks
http://www.jensen-transformers.com/an/an001.pdf

 indeed a properly implemented 49720NA can sound very good apparently, but most of us in this thread have never had the privilege of hearing any of this...49720NA was oscillating like hell on the Asus stx, it was audible too! 
	

	
	
		
		

		
		
	


	




 this said, I'm about the pull the trigger on this thing w/ 4*AD797BR and a pirate Lehmann headphones amp...running on a stabilized PSU, fed w/ 24/96 bit-perfect S/PDIF: HLLY HIGH END DMK-IV DAC USB Headphone AMP Pre-AMP [DMK-IV]


----------



## ROBSCIX

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_If you use LME497xx at low gain settings, I've found it's peaking. You have to use appropriate compensation caps. Furthermore it's more sensitive to interference than most opamps, and an input filter might be good idea. If properly implemented, I think it's quite neutral. I think it's a good opamp for the price, better than most, but there are more "musical" opamps to be found._

 

Many opamps can sound both good and bad depending on the rest of the circuit.


----------



## n_maher

Let's all calm down and try to keep this topic on topic, ok?


----------



## leeperry

one thing that baffles me is that AD797 says "(c) 1991" on its waffer print: 



 almost 20 years later, nothing good's happened for hifi-sound huh? ah well, 1991 was also the release date of the Sony cd3k...gotta be a sign! you can't improve on perfection, can you


----------



## Mad Max

Oh wow, in my Compass DAC, the LME49710NA (I only have the mono version) sounds very, very balanced with little bit forward mids and deep, tight, fast bass. It is very smooth sounding, not smeared, and revealing with good soundstage and very good top end extension. My only problem with this opamp is, again, the plastic sonic color and rolled-up highs. Otherwise, I would actually prefer this opamp in my DAC over the HDAM.
 Earth still has a substantial advantage with its holographic soundstage, but the LME is _potentially_ more neutral. No aggressiveness. I think with perhaps the right modifications, it may even sound very natural. Its highs aren't as dry as Earth's in my DAC, too.


 [irrelevance]
 That HLLY DAC seems to have a similar sound to the Audio-gd DAC19 based on skylab's review. I intend to upgrade to DAC19 + some headamp, a C-2 if I can't decide on anything else. The C-2 has CAST inputs to match to the DAC19's CAST outputs, but I would prefer something warmer than the C-2 since I use a bunch of bright headphones.
 [/irrelevance]


----------



## Mad Max

crud, double post


----------



## dex85

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_
 yes, rolling opamps is very dumb...hoping that an opamp will give its best w/o major circuit modifications is like believing that Jesus will come back anytime soon.

 this said, I'm about the pull the trigger on this thing w/ 4*AD797BR and a pirate Lehmann headphones amp...running on a stabilized PSU, fed w/ 24/96 bit-perfect S/PDIF: HLLY HIGH END DMK-IV DAC USB Headphone AMP Pre-AMP [DMK-IV]_

 

i see a lot of self-criticism there, considering it's coming from a very active op-amp roller 
	

	
	
		
		

		
		
	


	




 imo people are rolling op-amps to get a different sound, although the replaced op-amp may not work at its best in the circuitry. still, it's improvement for many despite being imperfect. there is nothing brainless about that.

 as for the pirates, do you really think they made any major circuitry changes or optimizations for ad797? they merely copy the other designs and change the thing or two(at least they admit it). whether the ad797 will be working at its best in that unit is very questionable.


----------



## leeperry

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_Oh wow, in my Compass DAC, the LME49710NA (I only have the mono version) sounds very, very balanced with little bit forward mids and deep, tight, fast bass. It is very smooth sounding, not smeared, and revealing with good soundstage and very good top end extension. My only problem with this opamp is, again, the plastic sonic color and rolled-up highs. Otherwise, I would actually prefer this opamp in my DAC over the HDAM.
 [..]
 That HLLY DAC seems to have a similar sound to the Audio-gd DAC19 based on skylab's review._

 

yes the 497xx will always have a very artificial sound, nothing you can do about that.

 the HDAM are nice, but too distorted and colored IMHO, it gets odd very quickly...the new Burson kills them in each and every department IME.

 the HLLY DAC Skylab tried seemed to run OPA2134 instead of AD797...no competition here, anything would sound like *** w/ a 2134 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *dex85* /img/forum/go_quote.gif 
_i see a lot of self-criticism there, considering it's coming from a very active op-amp roller 
	

	
	
		
		

		
		
	


	




 imo people are rolling op-amps to get a different sound, although the replaced op-amp may not work at its best in the circuitry. still, it's improvement for many despite being imperfect. there is nothing brainless about that.

 as for the pirates, do you really think they made any major circuitry changes or optimizations for ad797? they merely copy the other designs and change the thing or two(at least they admit it). whether the ad797 will be working at its best in that unit is very questionable._

 

it's brainless coz it can't work, by design.

 oh yes, lesson learned..Andrea opened a thread about op-amp rolling on diyaudio.com and ppl like Mooly tried to explain him on many many occasions, and even prove him by A+B that you CANNOT roll op-amps blindly.

 I had a lot of fun doing it(see it as assembling LEGO's, crossing your fingers and hoping for the best 
	

	
	
		
		

		
		
	


	




), but I still think that BLIND opamp rolling is pointless and will never lead to anything but sheer frustation...you can get "easy to live" opamps to sound good right away, like OPA2132 and so...but well, they're colored to death! they will last a week or so before you ditch'em 
	

	
	
		
		

		
		
	


	




 and the best sounding opamps(the top sections in majkel's list) are not "drop-in" replacements to anything...they need to be used in the right design.

 well as long as the AD797 doesn't oscillate on the HLLY, I'll be pretty darn happy..as they would install BR instead of AR at my request, I'm now trying to push to get a 24/96 USB chip(instead of 16/48) and/or possibly a BNC coax input


----------



## Mad Max

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_...
 the HDAM are nice, but too distorted and colored IMHO, it gets odd very quickly...the new Burson kills them in each and every department IME.

 ..._

 

I read the new Burson is like Moon. I'm not very fond of Moon, its sound just isn't to MY liking.
 I was saying I would prefer the more neutral LME, but the Earth is very much to my liking as well in the Compass. It's relatively colorless, just a tad bit bassy, no oddities. The one that does sound odd, though, is LT1357. Then the Compass itself is inherently warm, full, rich, and a bit bassy as well.
 The Compass is probably tweaked to sound best with the HDAMs, I guess.


----------



## ROBSCIX

Quote:


  Originally Posted by *dex85* /img/forum/go_quote.gif 
_i see a lot of self-criticism there, considering it's coming from a very active op-amp roller 
	

	
	
		
		

		
		
	


	




 imo people are rolling op-amps to get a different sound, although the replaced op-amp may not work at its best in the circuitry. still, it's improvement for many despite being imperfect. there is nothing brainless about that._

 

Have you had a chance to check out the new OPA164X opamps from Texas insturments? Initial testing is promising...


----------



## leeperry

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_I read the new Burson is like Moon. I'm not very fond of Moon, its sound just isn't to MY liking._

 

the old burson is exactly the same as Earth apparently, and the new one is a very much improved Earth...everything's better basically: more natural SS, better separation, less distorted sound.

 I also tried the 3 A-GD parts...Moon was unbearable, Sun V2 missing tonal nuances were making me feel half-deaf and Earth was nice...until I heard the new burson 
	

	
	
		
		

		
			





 there's always something better sounding in audio, one upgrade always kills the previous one


----------



## dex85

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Have you had a chance to check out the new OPA164X opamps from Texas insturments? Initial testing is promising..._

 

not yet. i might put a halt on op-amp rolling since with every swap there are usually things i like better but at the same time i miss some aspects of previous setup. now i tend to listen more to the sound then to the music, + op-amp rolling get expensive after while 
	

	
	
		
		

		
		
	


	




 i'm interested in Audio-Gd 19 as well, waiting for more impressions


----------



## K3cT

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_there's always something better sounding in audio, one upgrade always kills the previous one 
	

	
	
		
		

		
		
	


	


_

 

Right. Like these new Analog Devices ADA4627-1s.


----------



## SpudHarris

My preferences are:

 AD797B > OPA1641 > ADA4627-1


----------



## 12Bass

Hmmm.... Have a pair of AD797ANZ here.... non-fatiguing, fairly open, yet I find them sort of boring sounding, dunno... sort of "transparent, but lifeless". Maybe a bit too laid back for me? I don't think they sound bad.... just not that inspiring.


----------



## 12Bass

Side note: posting on this board is frustrating. Freezes up for a minute... double posts.... ARGH!!!!


----------



## SpudHarris

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Hmmm.... Have a pair of AD797ANZ here.... non-fatiguing, fairly open, yet I find them sort of boring sounding, dunno... sort of "transparent, but lifeless". Maybe a bit too laid back for me? I don't think they sound bad.... just not that inspiring._

 

Sounds the polar opposite to most views here 
	

	
	
		
		

		
		
	


	




. What circuit are you using them in? They are the best sounding opamp by a long way, the nearest being OPA1641's to my ears...


----------



## majkel

B series is like vinyl against ANZ sounding harder and dryer, more digital. Actually, the only chip from AD I know can be better, more snappy and transparent than the AD797BRZ is AD8021 but it's another nasty beast, more than the OPA228. It needs optimized resistance values for variuos gains to have THD minimized. For instance, when you decide to use it as a unity gain buffer, a single wire from the output to the In- pin will make it sound specific, a bit offensive and colored but when you put 240 ohm resistor instead, this is amongst the most transparent piece of silicon I have ever tried. The issue for me was that I raised the supply voltages above its limits to satisfy HDAMs better and the stock DIY DAC kit feedback loops make it oscillate. However, in buffer/amplifier applications it was damn good. However, it needs careful datasheet reading before application, it's not a drop-in for sure but another example of what _leeperry_ wrote. The decompensated op-amps are the most transparent probably due to minimum phase shifts.


----------



## 12Bass

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Sounds the polar opposite to most views here 
	

	
	
		
		

		
		
	


	




. What circuit are you using them in? They are the best sounding opamp by a long way, the nearest being OPA1641's to my ears..._

 

Opposite? Can you explain why you think my description is "polar opposite"? I thought most people found AD797 transparent sounding, not harsh, etc...? 

 In my listening tests, I prefer OPA211. It has a little more sparkle on top and a more interesting tonality. In comparison, I find AD797 neutral, tending toward bland. Not sure which is more accurate. I've tried them in a few places and the signature didn't change much that I recall. Will do some more listening....


----------



## leeperry

OPA211 has always been a digital artifacts feast for me...AD797B does sound vynilistic, use some VST plugin to add crackles on top..and you're right there


----------



## 12Bass

Hmmm...... was never much of a vinyl fan... so I'm not sure I'd want active components that sound like it. I don't hear anything "digital" in either of those chips. I hear different characters, sure, but nothing I'd identify as "digital". Don't hear heavy coloration in either of those two, at least as compared to something like OPA2134. Maybe we're using different meanings for the terms???


----------



## SpudHarris

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Opposite? Can you explain why you think my description is "polar opposite"?_

 

Errrm....yeah sure can. You said ''Boring'' & ''Lifeless'' that's Polar Opposite to how most here would describe the AD797's 
	

	
	
		
		

		
		
	


	




. That's why I asked about the circuit you were using them in.


----------



## 12Bass

From what I've read, I'm wondering if some aren't hearing the effect of the AD797 oscillating, as that might be contributing to a sharper sound in some setups? I'll listen again, but my recollection is that it sounds fairly natural and relaxed.


----------



## 12Bass

This seems similar to my experience: http://www.head-fi.org/forums/f6/ad7...should-278017/

  Quote:


 I implemented AD797 in a bad way and found the sound to be colored. Now it's better implemented and it sounds very neutral, and it has become my favourite opamp. Very smooth and unfatiguing, maybe there's a lack of aggressiveness.


----------



## ROBSCIX

The AD797, is known to be hard to stabilize in some circuits.


----------



## K3cT

I'm curious to try that AD797 mod but I'm not sure since the thing already sounds so bloody good now.


----------



## SpudHarris

Which mod?


----------



## K3cT

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Which mod?_

 

Adding a small capacitor between Pin 6 and 8 for "distortion cancellation", it's in that linked thread in the previous page.


----------



## SpudHarris

Ahh, sorry. Struggling to keep up with recent events etc..... yeah I've got some adapters coming with a place specifically for this. Need to check for capacitor values though. I'll go back and have a look. Good god, imagine the AD797 sounding even better


----------



## diditmyself

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Ahh, sorry. Struggling to keep up with recent events etc..... yeah I've got some adapters coming with a place specifically for this. Need to check for capacitor values though. I'll go back and have a look. Good god, imagine the AD797 sounding even better 
	

	
	
		
		

		
		
	


	


_

 

This is not a mod. It's described in the data sheet. You're supposed to use a 50 pF cap, but I think 47 pF is close enough. If you have a buffer after AD797, a tweak is to connect this cap from the output of the buffer to pin 8.


----------



## ROBSCIX

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_This is not a mod. It's described in the data sheet. You're supposed to use a 50 pF cap, but I think 47 pF is close enough. If you have a buffer after AD797, a tweak is to connect this cap from the output of the buffer to pin 8._

 

Let us know what you find.


----------



## SpudHarris

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_This is not a mod. It's described in the data sheet. You're supposed to use a 50 pF cap, but I think 47 pF is close enough. If you have a buffer after AD797, a tweak is to connect this cap from the output of the buffer to pin 8._

 

Yeah,, I printed out the 36 pages of Walt Jung Op Amp Aplications for a bit of ''toilet reading'' and picked that up. Not sure I'll bother though as I'm lovin the 797's as are.......


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Yeah,, I printed out the 36 pages of Walt Jung Op Amp Aplications for a bit of ''toilet reading'' and picked that up. Not sure I'll bother though as I'm lovin the 797's as are.......
	

	
	
		
		

		
		
	


	


_

 

I have stacks of printed PDF's, audio design books...etc. I need to get a PDF reader would save quite a few trees in the long run.


----------



## qusp

limiting the bandwidth of 797 works quite well for stabilty too, since we dont use nearly its capabilities in audio. i'm actually using some AD797 in some super regulators, so i'm poised to love it even more.


----------



## K3cT

Apparently the AD797 can be decompensated too by adding 2 resistors in the datasheet. Very interesting!


----------



## Spacehead

How to make the OPA552 stable in unity gain (virtual ground buffer)? Any example circuits? I tried the circuit in its datasheet but it didn't work.


----------



## majkel

Buy OPA551.


----------



## ROBSCIX

Have you had a chance to test the new OPA164X series Majkel?


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Yeah,, I printed out the 36 pages of Walt Jung Op Amp Aplications for a bit of ''toilet reading'' and picked that up. Not sure I'll bother though as I'm lovin the 797's as are.......
	

	
	
		
		

		
		
	


	


_

 

Spud, have you tested both the 164X? Meaning single and dual channel version?


----------



## SpudHarris

Only the singles Rob (OPA1641). They are real nice......... especially considering cost.


----------



## tdn135

Could you guys please give me advice? I would like to change opamps on my soundcard. I have a Auzentech X-Plosion soundcard and Alessandro MS-1 headphones.

 The stock opamps are AUK S4580P 615G. Most of the time I listen to rock and heavy metal. 
 Which, not too expensive, opamps can you guys recommend? 

 Thank you!

 This is the card: http://lib.store.yahoo.net/lib/xoxid...ion-card-1.jpg


----------



## ROBSCIX

Quote:


  Originally Posted by *tdn135* /img/forum/go_quote.gif 
_Could you guys please give me advice? I would like to change opamps on my soundcard. I have a Auzentech X-Plosion soundcard and Alessandro MS-1 headphones.

 The stock opamps are AUK S4580P 615G. Most of the time I listen to rock and heavy metal. 
 Which, not too expensive, opamps can you guys recommend? 

 Thank you!

 This is the card: http://lib.store.yahoo.net/lib/xoxid...ion-card-1.jpg_

 

You can go with some LM4562NAs, they sounded pretty good on that card IIRC.
 The great thing about having a socket for each set of outputs is you can use different opamps
 for different outputs. Such as using a great bass opamp for the bass channel and using opamps that are really clear for the front outputs for surround systems.
 I know you asked about headphone so this may not apply to you but you can keep it in mind. If your going to be using headphones only then you can just change the
 front channel opamp to keep the costs down for you.


----------



## leaf

Can anyone tell me how to orientatate the opa AD797BRZ for insertion please? 2 pieces are mounted on one Browdog adaptor, one one top and the other at the bottom. However, the adaptors do not have the semi-circular marking at the edge for me to follow. Thanks.


----------



## ROBSCIX

The brown dog should have some type of mark to signify which is pin one.

 Does one of the pins have a square solder pad? That is pin one and you can use it to orient the module to the socket.


----------



## leaf

Yes, there is a square solder pad and it is marked as 1.

 Sorry for this stupid question, but how do I orientate it? Normally I just follow the semi-circular marking. But in this case there is no such marking on the browndog.


----------



## scorpionro

Any idea where / how I could AD797BRs pre-mounted on a DIP8 adapter ?


----------



## ROBSCIX

Quote:


  Originally Posted by *leaf* /img/forum/go_quote.gif 
_Yes, there is a square solder pad and it is marked as 1.

 Sorry for this stupid question, but how do I orientate it? Normally I just follow the semi-circular marking. But in this case there is no such marking on the browndog._

 

Well the pin one shows the same end as the semi circular mark would be at.

 If your socket has the notch on the top, put the opamp with the pin one to the top of the socket. 

 If your still unsure I will see if I can find a pic for you.

 Here this might help more: LINK


----------



## ROBSCIX

Quote:


  Originally Posted by *scorpionro* /img/forum/go_quote.gif 
_Any idea where / how I could AD797BRs pre-mounted on a DIP8 adapter ?_

 

Not sure if anyboldy sells them pre-mounted but may be wrong about that. There are many around that can mount them for you if you buy them.


----------



## tdn135

Quote:


  Originally Posted by *scorpionro* /img/forum/go_quote.gif 
_Any idea where / how I could AD797BRs pre-mounted on a DIP8 adapter ?_

 

I saw this on ebay: Dual to Mono Op amp module 4558 NE5532 TL072 to AD797BR - eBay (item 360231530034 end time Mar-04-10 00:18:13 PST)

 I don't know for sure if they are orginal. Based on the reputation of the seller I guess they are. They are just $18.


----------



## H22

I could use some advice from the op-amp guru's.

 I have a mini3 board and want to try a different chipset. 
 I like the AD8397 and OPA690 combo, but want to try something that has a different signature. 

 So, since there are SMD opamps...and dificult to roll, I would love to get recomendations for "top of the line" opamp(s) that would work good on this platform. 
 It's a dual SOIC8 signal chip and a single SOIC8 for the active ground. voltage suply is through a split rail IC and can is 8.4-12.6v. 
 I have resistors for a gain of 5 but that can be changed as needed. 
 Joe


----------



## H22

sorry, double post...


----------



## leaf

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Well the pin one shows the same end as the semi circular mark would be at.

 If your socket has the notch on the top, put the opamp with the pin one to the top of the socket. 

 If your still unsure I will see if I can find a pic for you.

 Here this might help more: LINK_

 

Thank you very much. Your info. was of great help. This forum is not only informative but helpful 
	

	
	
		
		

		
			





.


----------



## qusp

Quote:


  Originally Posted by *H22* /img/forum/go_quote.gif 
_I could use some advice from the op-amp guru's.

 I have a mini3 board and want to try a different chipset. 
 I like the AD8397 and OPA690 combo, but want to try something that has a different signature. 

 So, since there are SMD opamps...and dificult to roll, I would love to get recomendations for "top of the line" opamp(s) that would work good on this platform. 
 It's a dual SOIC8 signal chip and a single SOIC8 for the active ground. voltage suply is through a split rail IC and can is 8.4-12.6v. 
 I have resistors for a gain of 5 but that can be changed as needed. 
 Joe_

 

you could install an adapter until you find something that suits your liking. the problem is though, the mini^3 is very specifically designed around those opamps, so decoupling and feedback will be tuned to get the best out of them. dropping a new opamp in without changing all of this may be less than optimal to say the least and downright bad at the worst. I could list literally heaps of opamps that beter the 8397 to these ears, but how well they will w0ork in the mini63 circuit is another thing.

 OPA1612 might be a good start or OPA2211 and for the buffer hmm AD811? actually OPA1611 and OPA211 are really nice buffers too. sorry I diont have time ti look specifically at the design of the mini^3 and datasheets of the chips for recommendations, but yeah I would consider installing sockets temporarily. LT1028 makes a great low noise ground channel opamp, but its a little sensitive and needs to bepampered a bit. also might not perform at your supply voltage. scratch that, it wont. AD8616 will


----------



## scorpionro

Quote:


  Originally Posted by *tdn135* /img/forum/go_quote.gif 
_I saw this on ebay: Dual to Mono Op amp module 4558 NE5532 TL072 to AD797BR - eBay (item 360231530034 end time Mar-04-10 00:18:13 PST)

 I don't know for sure if they are orginal. Based on the reputation of the seller I guess they are. They are just $18._

 

Nice find. Thanks. Any idea if these would work as i/v for a xonar essence st ( I did use the search, but couldn't find anyone who tested these on an essence st ) ?


----------



## kranius

they would work, but fear the oscillation 
	

	
	
		
		

		
		
	


	




 EDIT : btw those modules are dual to single, you need dual opamps for stx

 get adapters and AD797BN


 PS : has someone heard the new LME49990 ? datasheet


----------



## ROBSCIX

Quote:


  Originally Posted by *kranius* /img/forum/go_quote.gif 
_they would work, but fear the oscillation 
	

	
	
		
		

		
			





 EDIT : btw those modules are dual to single, you need dual opamps for stx

 get adapters and AD797BN_

 

I thnk tha is the right model but something has been lost in translation. If you read down a bit it says:
 include: TWO SOIC AD797BR With ONE Single Dual Op Amp to Dual Op Amp adapter.

 The AD797's are "mono" -single channel chips so if they are using two on this unit then it is a dual channel model. These would work for the STX sockets, if they will stabalize is another question. I have tested this model for buffer and it was fine but not for I/V.


----------



## kranius

my bad, I've misread the link 
	

	
	
		
		

		
		
	


	




 thanks for correction


----------



## kuben

Can someone tell me which best opamps should i choose for stx?
 Those?AD843SQ /883 high speed high current opamp 1 pair !! - eBay (item 320392642724 end time Feb-27-10 00:40:20 PST)


----------



## ROBSCIX

There is no such thing.... There are different opinion on units that sound good to others but there is not nor will ever be a best opamp.
 Many have had good results with the LME49720NA's in the I/V. Some use the metal can LME49720HA version also.


----------



## SpudHarris

Quote:


  Originally Posted by *kuben* /img/forum/go_quote.gif 
_Can someone tell me which best opamps should i choose for stx?
 Those?AD843SQ /883 high speed high current opamp 1 pair !! - eBay (item 320392642724 end time Feb-27-10 00:40:20 PST)_

 

What I would say is man, those are expensive 
	

	
	
		
		

		
		
	


	




 I have the KN version and I really like them but there are better Opamps IMHO. That said, it is a matter of personal preference, source, application, circuit, phones, speakers, musical tastes etc...etc... so many variables. A lot of people do seem to agree on the AD797B's being exceptional though, myself included.

 My personal application is a Fi-Quest Headphone Amp with the AD797's in L/R with High Bandwidth BUF634's and nothing in ground.


----------



## leeperry

so how good's OP275 anyway? some ppl seem to looooooove it: So many DACs, which to choose - Page 3 - diyAudio

 and my next soundcard comes w/ them stock, soldered 
	

	
	
		
		

		
		
	


	




 I read through google that 12bass didn't like them, but he also doesn't like AD797...so we'll just have to agree to disagree.
  Quote:


  Originally Posted by *kuben* /img/forum/go_quote.gif 
_AD843SQ /883 high speed high current opamp 1 pair !! - eBay (item 320392642724 end time Feb-27-10 00:40:20 PST)_

 

good to see that ceramic has become "audiophile" now


----------



## SpudHarris

I have an OP275 on back order from Farnell which I'm looking forward to testing. I soldered up another couple of AD825's this evening and am listening in the Fi-Quest and I have to say these things are impressing me. I don't think I've ever tried them with high bandwidth buffers before but the micro dynamics are really something. 

 Qusp, I know you aren't a big fan but have you tried these in your Fi-Quest with Hi-C buffers? May be the Fi-Quest just brings out the best in Opamps


----------



## 12Bass

It's not that I dislike AD797.... just find it a bit laid back/uninteresting. OP275 adds more character, but sounds a bit compressed/distorted/EQed somehow. Definitely more colored than AD797, and not something I would use if transparency were important.


----------



## 12Bass

AD825 can sound good in some applications, and can impart a bit of a "loudness" EQ effect (bass/treble enhanced). Overall, I find the OPA827 more neutral sounding.


----------



## 12Bass

BTW, I've got some OP275 DIPs lying around if someone wants them for the cost of postage.


----------



## qusp

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I have an OP275 on back order from Farnell which I'm looking forward to testing. I soldered up another couple of AD825's this evening and am listening in the Fi-Quest and I have to say these things are impressing me. I don't think I've ever tried them with high bandwidth buffers before but the micro dynamics are really something. 

 Qusp, I know you aren't a big fan but have you tried these in your Fi-Quest with Hi-C buffers? May be the Fi-Quest just brings out the best in Opamps 
	

	
	
		
		

		
		
	


	


_

 

OK i'll give them a go in the FiQ, hey I like the AD825....as IC1 in super regulators 
	

	
	
		
		

		
		
	


	




 joking aside its a nice opamp, like 12bass says they are a touch coloured, but they really are great little performers in regulators and reasonably priced.


----------



## SpudHarris

Well I had an extended listening period with the AD825's and just didn't want to go to bed. I listen to a lot of Ambient Trance and I'm picking out micro details that makes me grin from ear to ear. Don't tell me it's distortion


----------



## majkel

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_so how good's OP275 anyway?_

 

I think "mediocre" is the best word.


----------



## leeperry

hah, ok! well, the 1028A/797B require tailor made designs anyway...I've even see than in the Fi-Quest they put special jumpers for them.

 the HLLY amp had four 797 as preamp, but a lousy 2134 as in the HP amp...and 16/48 max over USB.

 the Musiland Monitor 02US runs on its own cheapo SMPS(no nasty 5V from the PSU), does 24/192 bit-perfect and sounds pretty damn good for the 100 EUR shipped it costs apparently....and the DAC they used doesn't need I/V: Computer Audio Asylum - RE: Musiland Monitor 01 US - more listening - jkeny - December 29, 2009 at 11:41:53
  Quote:


 the PCM1793 is a Vout DAC with a bias voltage of 1.65 on each differential output leg - so the op-amp is only performing DC blocking function & also upping the output signal voltage to 2V 
 

there's no perfect world, I know what I want but it cannot be done w/o major changes...blind opamp rolling is pointless, and sockets kill the SQ...time to make compromises! 
	

	
	
		
		

		
		
	


	




 I've seen a thread about rolling the OP275 on their official forum, but you cannot read any topic w/o speaking chinese(due to anti-bot policies).


----------



## ROBSCIX

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I think "mediocre" is the best word._

 

Nicer word then I would have used.


----------



## Incognito73

Hey there,

 What's your take on buying opamps from E-bay/China ? I want so source some good opamps for Auzen Bravura (and general hi-fi use). I've seen some interesting offerings from ebay sellers "audjade_chn" and "tube_buyer" but obviously I'm paranoid about the fakes.

 Here in the UK prices are over the roof for good opamps (usually more expensive then the audio card itself) ... so is it possible to have economical-non-fake option ? or is that just utopistic thought


----------



## MikeW

Hey guys, I've read alot of this thread and wanted to get your take on this. 

 I've got a Head-Direct EF-5 hybrid amp, i've been playing with rolling a few different op amps in it. I don't know alot about the circuit but i'll try to explain it. 

 I think the op-amp is "Behind a buffer" the socket is surrounded by resisters, 2 orange ceramic caps,1 metal-can looking tantalum. And next to it are 4 "Transistors" with large heatsinks on them. The stock op-amp is OP275. It also has 2 things next to the socket that look like resisters, but may be coils or something else, they are smaller then a typical metal-film resister, and are bright yellow, maybe they are inductors. 

 It's a DIP-8 package. 

 So far i've tried AD743JN, OPA2227PA, LME49860, and the stock opamp, OP275. 

 There are things from all 4 of these opamps that I enjoy, and things they get wrong. LME49860 is a bit to detailed and the soundstage is "off" to me. AD743JN's are nice, but they are a little to fat with a loss of focus, especially compared to 49680. I was actually pretty surprised with opa2227pa, I took it out of my cmoy and tried it for fun. It had very nice low end, and mid-range, but the high's where lacking. The OP275 is pretty good too, but it's fat and lacking in the highs. I've considered the following opamps 

 AD797ANZ (Dip 8 pkg limitation) 
 LT1028A 
 LT1358
 LT1122 
 LT1364
 LT1363
 OPA2228PA
 OPA627B

 I have not tried any of the above. What are your thoughts?

 edit: can you use this Single-to-dual Op-AMP Adapter - DIP version (p/n 021001) for SOIC to DIP x2.


----------



## kuben

Ok so i have narrowed it down to:
 1xAD797BRZ buffer
 2xOPA827 I/V
 I need some adapters to fit them in STX? If yes link them please.
 And do i need to solder them?


----------



## kuben

So i need 2 AD797BRZ in Single-to-dual adapter for buff and 2 opa827 without adapter in I/V?


----------



## Incognito73

... I'm very new with the opamp swapping terminology. Can some kind soul explain to me what does exactly I/V and buffers means related to audio cards ?

 For example, currently I have AudioTrak 7.1HiFi upgraded with 5xLM4562. If I want to experiment further (mix & match other opamps) how would I know which channel (opamp slot) is buffer or I/V ?!


----------



## kranius

Quote:


  Originally Posted by *kuben* /img/forum/go_quote.gif 
_Ok so i have narrowed it down to:
 1xAD797BRZ buffer
 2xOPA827 I/V
 I need some adapters to fit them in STX? If yes link them please.
 And do i need to solder them?_

 


 you need this one for AD797

 and that one for OPA827

 for the first you can get it with sockets installed, so no soldering needed, but not for the other one


----------



## SpudHarris

Quote:


  Originally Posted by *Incognito73* /img/forum/go_quote.gif 
_Hey there,

 What's your take on buying opamps from E-bay/China ? I want so source some good opamps for Auzen Bravura (and general hi-fi use). I've seen some interesting offerings from ebay sellers "audjade_chn" and "tube_buyer" but obviously I'm paranoid about the fakes.

 Here in the UK prices are over the roof for good opamps (usually more expensive then the audio card itself) ... so is it possible to have economical-non-fake option ? or is that just utopistic thought 
	

	
	
		
		

		
		
	


	


_

 

Be very carefull. When I was starting out on the voyage to find the best opamps for my PPA I got stung buying OPA637's. I got my money back eventually through Paypal and I helped TI to get to the source but I still see them trading so they didn't get too bothered.

 I always use Farnell for my opamps and some other DIY stuff. The nice thing is there is no carriage charges and they deliver next day nearly every time. I've got quite a few different opamps still in the packaging do you know what you are after?

 Edit: Just to avoid confusion the fakes I bought were not from the sellers you mention.


----------



## SpudHarris

Quote:


  Originally Posted by *kranius* /img/forum/go_quote.gif 
_you need this one for AD797

 and that one for OPA827

 for the first you can get it with sockets installed, so no soldering needed, but not for the other one_

 

He'll only need that for the 797's if he manages to get the 797's in a DIP8 package. The majority of 797's are now SOIC so the link for the other adapter (2 x SOIC to DIP) would be relevant for both opamps and require soldering.


----------



## tdn135

Which opamps for a auzentech x-plosion card should I get from TI.com? There are so many samples listed. I don't know which one to take. Which samples would you recommend or should I just buy a few from farnell?


----------



## Incognito73

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Be very carefull. When I was starting out on the voyage to find the best opamps for my PPA I got stung buying OPA637's. I got my money back eventually through Paypal and I helped TI to get to the source but I still see them trading so they didn't get too bothered._

 

Yeah. I'v read the stories. I guess that because it's such distant trade, any effort to put the things into the right perspective is enormously difficult.

  Quote:


 I always use Farnell for my opamps and some other DIY stuff. The nice thing is there is no carriage charges and they deliver next day nearly every time. 
 

Yeah, Farnell is superb. I'v bought 5xLM4562, some LT1364 and LT1361 opamps, some DIY stuff too ... exemplary trader.

  Quote:


 I've got quite a few different opamps still in the packaging do you know what you are after? 
 

Well, for the Auzen Bravura I think it's the safest route to pick something from their list here. At least I would be safe from opamp stability problems as models are certified by them. OPA627 or AD797 would be nice ... or even AD8620. Interestingly enough, Farnel has an excellent price for AD797ANZ but only for 10+ pieces (then is going half price from 8£ to 4£ per piece ). OPA627 is way too expensive there ... 

  Quote:


 Edit: Just to avoid confusion the fakes I bought were not from the sellers you mention. 
 

Sure.


----------



## SpudHarris

Periodically if you subscribe to their e-mail newsletter you can get a bargain here and there.


----------



## ROBSCIX

Ebay is full of guys selling fake OPA6X7's as many are interested in these units and they can ask a hefty price because of the model. You would have to cross-reference the serial number with the company to verify if they are legitimate or not.


----------



## ROBSCIX

Quote:


  Originally Posted by *kuben* /img/forum/go_quote.gif 
_Ok so i have narrowed it down to:
 1xAD797BRZ buffer
 2xOPA827 I/V
 I need some adapters to fit them in STX? If yes link them please.
 And do i need to solder them?_

 

That would be a pretty good combo. All those units work in that circuit also as I have used the OPA827's for I/V in that circuit and the OPA797 for buffer. However, I have never used them in that configuration you suggested though.
 Both units are single channel so either way you will require two of each chip for 1 module. You can just go DIp8 with the AD797 if you can find them in that format as it will save you some soldering. The oPA827 you will have to solder on an adapter. You can always have another person make the units for you, if you have buddy that has the skills.


----------



## synth123

So ROBSCIX do i understand this correctly the STX/ST will not support 797BR in the I/V positions (due to circuit design) but the 797BR in the buffer position will be ok (all with dual adapters of course)

 Thanks,


----------



## MikeW

no replies eh? Should I take the plunge on the Browndog SOIC adapter and a pair of AD797BRZ? 

 How do you know the orientation of those SOIC chips anyways. They don't seem to have a half moon like DIP 8's.


----------



## SpudHarris

MikeW - the adapter you linked in your earlier post is for DIP8 chips. If you are getting 2 # AD797BRZ's You will need either 2 of these *OR* 1 of these and a steady hand for soldering.

 The orientation is marked by a very small dot or circle at pin # 1 of the chip, this then corresponds with a dot or circle on the adapter also. If you look closley they are visible on the adapters I've linked. Just for clarity there are other adapters available apart from Browndogs (bit flimsy), These are the single units I get from e-bay and they are top quality.


----------



## majkel

There is a dot on top at pin 1. High input current bipolar op-amps aren't the best choice for I/V while they are great as output buffers, so the AD797 will be OK. Actually you'd better chosen a unity gain stable op-amp for I/V, too. The OPA827 fulfills both requirements and sounds nice.


----------



## leaf

I paid either US$49 or US$46, can't really recall, for 2 AD797BRZ to be mounted on these Single-to-dual Op-Amp Adapter (p/n 020302).


----------



## leeperry

BTW, a famous amp manufacturer just told me: 
  Quote:


 The only difference between the AD797A-B version is, that the B-version has been slightly better input offset voltages and input offset currents.

 As a disadvantage the B-version has a worse PSRR. It might be, that in your amp A- and B-version sounds different because the B-Version is more effected by the quality of the power-supply. 
 

they use A.


----------



## ROBSCIX

Quote:


  Originally Posted by *synth123* /img/forum/go_quote.gif 
_So ROBSCIX do i understand this correctly the STX/ST will not support 797BR in the I/V positions (due to circuit design) but the 797BR in the buffer position will be ok (all with dual adapters of course)

 Thanks,_

 

I never tested the AD797 in the I/V, only the buffer.


----------



## MikeW

Ouch that is really expensive. Soldering is no problem for me. 

  Quote:


  Originally Posted by *leaf* /img/forum/go_quote.gif 
_I paid either US$49 or US$46, can't really recall, for 2 AD797BRZ to be mounted on these Single-to-dual Op-Amp Adapter (p/n 020302)._

 

So can anyone tell me what "Application" my amp is using this opamp for? Is it I/V or Buffer? What does it mean that the opamps are surrounded by transistors? Browndog only sells the adapters 5 at a time, guess i could use some spares.

 That is interesting what you say about the a vs b version leeperry, would be alot less hassle for me to order dip-8 version of ad797. I already have a browndog for that.

 the AD827 is the easiest solution. It's dual channel, and dip. Simple drop in replacement for me. Hmmm..

 I really don't care for the sound of LME49680. I've switched back to my AD743JN's and enjoy them more. But i'd like a more focused faster, less fat sound then what 743's are giving me, but similiar signature. I like the high's to be airy but not overdone, and I feel like the LME49680 is seriously over doing them, the mid-range is a bit "off" too.


----------



## kuben

Maybe instead OPA827 i should choose OPA627?


----------



## SpudHarris

I prefer the OPA827 to the 627 by miles.

 Anyone have experience of the AD845? I was just reading some Opamp Application stuff by Walt Jung and it's mentioned a few times......


----------



## ROBSCIX

Quote:


  Originally Posted by *kuben* /img/forum/go_quote.gif 
_Maybe instead OPA827 i should choose OPA627?_

 

 The 627 is opretty price in comparison to the OPA827. The OPA827 is still really new in comparison and many suggest it is just as good as the OPA627. If you want to go for the OPA627 your going to have to spend a bit of cash.


----------



## kuben

Any foughts about OP27AZ and AD8610BRZ?


----------



## ROBSCIX

The AD8610 is the single version of the AD8620 and many like that chip also for audio work. Actually many of the Analog Devices chops are well received.


----------



## Kitarist

anyone knows where to buy some kits


----------



## SpudHarris

What do you mean by Kits?


----------



## K3cT

I'm trying the LT1115 now and on the onset, it seems to have a great timbre. Not as blazing fast as the AD797 or ADA4627 though but this particular op-amp has a very nice ring to it. Perhaps it's because it's designed for audio application?


----------



## SpudHarris

Hey Friend!

 I've ordered one of those from Farnell's but I can't get away from these AD797B's. The AD825 is also nice, to my ears at least...


----------



## K3cT

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Hey Friend!

 I've ordered one of those from Farnell's but I can't get away from these AD797B's. The AD825 is also nice, to my ears at least..._

 

Hi! I hope you're doing well with your op-amp experiments. 
	

	
	
		
		

		
			





 Man, I know what you mean but we are so obsessed with the AD797B we won't be able to appreciate a different kind of sound. 
	

	
	
		
		

		
		
	


	




 I have LT1115, LT1363 and TLE2141 to play around now. The AD825 is realllly good for the price it commends but seems to sound colored and a bit closed-in compared to the venerable AD797. The vocal is forward as well. It's definitely not as neutral as the 797 but man, it's a fun-sounding op-amp.


----------



## 12Bass

Funny... just looked through my collection and found tubes of OPA2134s, OPA275s, LM4562s, AD825s, plus some others that I'll probably never use. Should probably have an op amp sale one of these days....


----------



## ROBSCIX

Ill take them. if your just giving them away


----------



## 12Bass

Should have OPA1641/1642 on their way soon... with more adapters... and maybe a nice Chianti....


----------



## ROBSCIX

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Hi! I hope you're doing well with your op-amp experiments. 
	

	
	
		
		

		
		
	


	




 Man, I know what you mean but we are so obsessed with the AD797B we won't be able to appreciate a different kind of sound. 
	

	
	
		
		

		
		
	


	




 I have LT1115, LT1363 and TLE2141 to play around now. The AD825 is realllly good for the price it commends but seems to sound colored and a bit closed-in compared to the venerable AD797. The vocal is forward as well. It's definitely not as neutral as the 797 but man, it's a fun-sounding op-amp._

 

Well that's the point IMO, some opamps will sound neutral while others may provide aspects you find enjoyable. If that is the case then who is to say you are wrong?
 AFAIAC, if it sounds good to your ears then it is good. YMMV.


----------



## K3cT

Rob, of course you're correct but my desire to experiment is above all I think. 
	

	
	
		
		

		
		
	


	




 BTW, have you tried the 4627-1? What do you think of them?


----------



## SpudHarris

OP42AJ - These are expensive, has anyone got experience with them? Nice to find one I've never heard of. Described as ''Top Grade High Speed'' Opamp.


----------



## ROBSCIX

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_Rob, of course you're correct but my desire to experiment is above all I think. 
	

	
	
		
		

		
		
	


	




 BTW, have you tried the 4627-1? What do you think of them?_

 

I haven't got around to try them as of yet. Maybe I will sit down tommorow and build some units I have a stack of opamps sent to me by associates for my testing.


----------



## leeperry

hummm, I'd like to get a HP amp that's compatible w/ AD797B/LT1028A right off the bat..something dead simple: 2 RCA in>1 HP out, but apparently LT1028 is a lost cause w/o an oscilloscope and a proper design: Cmoy headphone amp? - diyAudio

 and tubes get hot as hell and are also a pain to roll...discrete is the only way I'm afraid


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_OP42AJ - These are expensive, has anyone got experience with them? Nice to find one I've never heard of. Described as ''Top Grade High Speed'' Opamp._

 

High speed can be an issue, espeically if you are unsure on how to stabalize them. Not saying they will be a problem, just high speed opamps can be quite touchy in many circuits. If you try them out let us know how it goes.


----------



## itszdenny

I am currently at a loss 
	

	
	
		
		

		
		
	


	




.

 I have multiple 8-msop and 8-soic op amps that I am looking for adapters for. I understand that some op amps are dual channel while some are single. For audio purposes, do I need to strictly use dual channel adapters, or this depends on the device I will be using the op amp in?


----------



## SpudHarris

Like you say it will depend on the device. Why not tell us more about the device you are intending to use them in and which opamps you have and we can steer you in the right direction.


----------



## ecclesand

Has anyone ever swapped out an AD841 (14DIP) with an 8DIP opamp in the I/V stage of a DAC? I have a Parasound 800 DAC that I recently received and it uses the AD841 as I/V. I compared the pins on the AD841 to other 8DIP opamps and the pins match up with the remaining 6 pins on the AD841 not being used.


----------



## ROBSCIX

Sounds like a quad opamp. They are just using the amps they want and leaving the others unused. If I am understanding you right.

 Provided the pin outs are the same, you can swap them out with dual channel version if you want.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Sounds like a quad opamp. They are just using the amps they want and leaving the others unused. If I am understanding you right.

 Provided the pin outs are the same, you can swap them out with dual channel version if you want._

 

Thanks, Rob but it is actually just a single opamp but in a 14DIP package. It's soldered directly to the board and I wanted to see if anyone had successfully swapped one out for a single channel DIP8 opamp. I most likely will destroy both AD841s when I desolder them and they are hard to find in small quantities.


----------



## Spacehead

I am listening now to AD8397+AD8599 combo. Got it properly working on my BD139x3 Class A amplifier which has tuned cmoy core. Soundstage is a little confined but detailed enough. A little fatiguing highs. Instruments feel far away. Very realistic anyway. Very fast of course. I think AD8397 is a bit muddy, but interesting and fun sounding op amp. AD8599 compliments it well in ground channel. 

 Overall I think my amplifier needs tuning still. Vocals seem too distant for my liking. Or then it is my headphones, Sennheiser HD 201 that lack mids too badly. Can't do a proper review with these phones! Soon I get Sennheiser HD 438, I hope they are better.


----------



## CodeToad

Currently running 3 x OPA1641's in an M3. Very nice. I think I like them better than OPA627's.


----------



## SpudHarris

x2 - Love OPA1641's! In my top 3 for sure........


----------



## ROBSCIX

I can agree on that one. I like the 1641's also....


----------



## 12Bass

Damn.... OPA1641s should be here tomorrow.


----------



## ecclesand

Where are you guys getting the OPA1641. Every place I have looked to buy them shows a lead time of a few months!

 EDIT: NM....found them in stock at Mouser.


----------



## fzman

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Sounds like a quad opamp. They are just using the amps they want and leaving the others unused. If I am understanding you right.

 Provided the pin outs are the same, you can swap them out with dual channel version if you want._

 

no, there are some weird opamps with are dip14, which only use 8 pins, and the rest are nc -- not sure why, but i have seen them


----------



## tdn135

Which opamp will be beter for rock/heavy metal on Auzentech X-Plosion with Alessandro (Grado) MS1i headset. AD797BR or OPA627AU? I can get them for the same price. 
	

	
	
		
		

		
			





 These are the links to seller:
Dual to Mono Op amp module 4558 NE5532 TL072 to AD797BR - eBay (item 350317485329 end time Mar-17-10 09:19:56 PDT)
Dual to Mono Op amp module 4558 NE5532 TL072 to OPA627 - eBay (item 360213670439 end time Mar-01-10 18:38:37 PST)


----------



## SpudHarris

I just ordered the 797BR's from there. Personally I prefer the 797's to the OPA627's but it's a personal preference.


----------



## crapback

I've never seen a custom painted 797 like that before. The ones I ordered from digi-key definitely don't look like that. I wouldn't be surprised if the only upgrade you'd be getting from that seller is the new paint. I'm calling shenanigans.

 Here is a link to genuine AD797BRZ's. Digi-Key - AD797BRZ-ND (Manufacturer - AD797BRZ)


----------



## SpudHarris

I thought that also but the ARZ's that come with the ibasso stuff are the same. NOS apparently and Audio jade have sold quite a few in the history section. I agree that e-bay isn't the ideal place for getting the genuine article but there are a few reputable sellers and Audio Jade does have good feedback. I got my last lot of BRZ's from Farnell but I've ordered one of those modules off the e-bay site and I'll report back if it is hookie!


----------



## crapback

I would love to be proved wrong. 
	

	
	
		
		

		
		
	


	




 The only other opamps I've seen painted like that were some DIP8 NE5532's I got with a gigawork DAC.


----------



## ROBSCIX

@Crap, are you talking about the units in the links in post #2228?

 These units are painted in the same way: 8620BR
 If you scroll down there is apicture that you can see they have similar paint.
 Same as this unit also:AD797

 They look similar to the units in the linked pic. Unless I am misunderstanding what paint your refering to.


----------



## crapback

Yup. I guess to me the paint looks like a cheap silkscreen afterthought. The paint just looks too cheap for me to think it's a factory job.


----------



## ROBSCIX

I have units from different sources and I have seen the AD units marked differently. Some have the full white with the black lettering and I have seem them just all black with white lettering like most other opamps. Both units were received from reptuable sources.

 It is great to point out if any of us think their are some fakes floating around because some times people new to the opamps don't realize these items can be counterfieted.


----------



## crapback

I get especially suspicious when it involves some of the most popular opamps on the market. If you or Spud will vouch for them that's good enough for me.


----------



## 12Bass

Quickly auditioned the OPA1641 tonight. Somewhat surprised me with how it seemed more open than the OPA827. In comparison, OPA827 seems a bit warmer and maybe "golden" sounding. OPA1641 might be a bit less colored, but I haven't had a chance to give it a proper listen yet.

 Just for fun, I made a dual OPA1641 8-pin DIP:







 Definitely NOT ROHS....


----------



## 12Bass

After a little more listening, I'm finding that my preferences between OPA827 and OPA1641 vary depending on where the chip is used. Still finding the OPA827 a bit warmer overall and generally pleasing sounding, while the OPA1641 might be a tad on the thinner/more open end of the continuum.... sounds a little less musical, perhaps?


----------



## ROBSCIX

Quote:


  Originally Posted by *fzman* /img/forum/go_quote.gif 
_no, there are some weird opamps with are dip14, which only use 8 pins, and the rest are nc -- not sure why, but i have seen them_

 

Really? That's different, I have never seen an opamp like that.


----------



## ROBSCIX

Quote:


  Originally Posted by *crapback* /img/forum/go_quote.gif 
_I get especially suspicious when it involves some of the most popular opamps on the market. If you or Spud will vouch for them that's good enough for me._

 

All I said, is I have seen them painted in such a way. I cannot vouch for a supplier I have never dealt with. Not sure if that helps.


----------



## MikeW

I got my browndog adapters in today. Soldered up the AD825 and 797. Im listening to the 825 now, I have not tried the 797 yet. What can I say? Im really really enjoying this 825 at the moment. It's a clear step over anything else i've tried in this amp. (LME49860, PA2227, OP275, AD743JN). 

 One problem though, the first time I put them in backwards.. I was worried I might have orientation wrong, there's no documentation on these browndogs which way is which. I watched them carefully and saw a tiny puff of smoke start and instantly switched the amp off. I flipped them and put them back in the right way and they seem to be working fine. What's the chance of them not being damaged?


----------



## Spacehead

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Just for fun, I made a dual OPA1641 8-pin DIP:






 Definitely NOT ROHS.... 
	

	
	
		
		

		
		
	


	


_

 

I have some OPA1611 op amps that could be used to replicate what you did, that looks pretty cool idea. 

 How long that took to finish?! Very precise work.


----------



## Spacehead

My current favorite is OPA2107. 
 I get DC Offset of 0.3 mV with it. That is pretty low 
	

	
	
		
		

		
		
	


	



 Sound is very spacious but still laid back and relaxed. 

 My previous favorite was AD8599 but I think my two chips are broken, one gives weird hissing sound that is very audible and another has DC offset of over +10V so it is definitely broken.


----------



## 12Bass

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_I have some OPA1611 op amps that could be used to replicate what you did, that looks pretty cool idea. 

 How long that took to finish?! Very precise work._

 

Took maybe an hour or so. Not for the faint of heart! I've cleaned it up a bit since the photo was taken. Sounds just fine.... OPA1641 is a nice chip. 

 First I cut off all of the NC pins from each op amp, then soldered in the bottom chip. Pins 2, 3, 4 all connect to their partners on the socket, while 6 goes to pin 1, and 7 to pin 8 of the socket. The top chip is more complicated, as its inputs (2, 3) have to be rerouted to 5 and 6, while output (6) goes to pin 7, with power again to 4 and 8. 

 Given the risk of ruining the chips and the fine soldering required, I'd suggest using a BrownDog 020302 (or similar) adapter instead.


----------



## 12Bass

Quote:


  Originally Posted by *MikeW* /img/forum/go_quote.gif 
_One problem though, the first time I put them in backwards.. I was worried I might have orientation wrong, there's no documentation on these browndogs which way is which. I watched them carefully and saw a tiny puff of smoke start and instantly switched the amp off. I flipped them and put them back in the right way and they seem to be working fine. What's the chance of them not being damaged?_

 

Pin 1 on the top of the 020302 is square, while the others are round. Releasing magic smoke is usually a bad thing. Hard to tell what the damage might be unless you have known good chips for comparison. Putting things in backwards will often kill them, but sometimes they survive and continue to function. Might want to put a small dot on pin 1 with a marker for future reference.


----------



## itszdenny

Do the numbers on a msop chip mean anything? I mixed up a few of my op amps


----------



## opamp_addict

Some more listening....
 I must say the EL2125CSZ really gives me some suprise.










 I've seen soic16 to dip8, emm may be going to build some of that later.


----------



## MikeW

I did not solder it backwards, that's not the issue, as the chip and adapter are clearly marked. I put the completed (properly soldered) adapter into the dip-8 socket (on my amp) the wrong way. 

  Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Pin 1 on the top of the 020302 is square, while the others are round. Releasing magic smoke is usually a bad thing. Hard to tell what the damage might be unless you have known good chips for comparison. Putting things in backwards will often kill them, but sometimes they survive and continue to function. Might want to put a small dot on pin 1 with a marker for future reference._


----------



## 12Bass

Quote:


  Originally Posted by *MikeW* /img/forum/go_quote.gif 
_I did not solder it backwards, that's not the issue, as the chip and adapter are clearly marked. I put the completed (properly soldered) adapter into the dip-8 socket (on my amp) the wrong way._

 

Right... and pin one on the BrownDog adapter is square, and has a small number 1 just to the left of it. So, yes, there is marking on the adapter to indicate which way is which.


----------



## MikeW

ahh, yeah i see it now. Thanks


----------



## SpudHarris

Quote:


  Originally Posted by *opamp_addict* /img/forum/go_quote.gif 
_Some more listening....
 I must say the EL2125CSZ really gives me some suprise._

 


 That AD745 looks nice, where can we get those?

 Also can you elaborate on the EL2125? World Class?


----------



## SpudHarris

OPA2111AM (metal can) any love for these??

 I happen to think that the OPA2111KP is the absolute best suited chip for the P3+ circuit period and pretty fine in a few others too. These AM's retail for just under £40 from Farnell and I just picked one up on e-bay here in the UK for £5.95


----------



## qusp

sounds like a fake 
	

	
	
		
		

		
		
	


	




 I like the 2111 too, enjoyed it a great deal in my D10


----------



## SpudHarris

Normally I'd agree Jeremy but it's a UK seller with mint feedback. We'll soon see anyhow and it's not much of a gamble at £6. I'll know as I'm familiar with every nuance of this chip as It's not moved from my P3+ for probably 5 months or so.


----------



## ROBSCIX

The 2111 AM are said to be great opamps..but I have not tested them myself.


----------



## SpudHarris

The guy I'm getting these off also includes one of these for the TO99's so they just drop into DIP sockets, didn't even know they existed 
	

	
	
		
		

		
		
	


	




 By the way he has a fair few of these so anyone interested I can buy and send on or hook you up...


----------



## Kitarist

So which of these is best?


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_The guy I'm getting these off also includes one of these for the TO99's so they just drop into DIP sockets, didn't even know they existed 
	

	
	
		
		

		
		
	


	




 By the way he has a fair few of these so anyone interested I can buy and send on or hook you up..._

 

Interesting, I have never seen that type of adapter either. 
 He has a few of the opamp or a few of the adapter?


----------



## SpudHarris

Both I think, mine were posted out yesterday so should be here tomorrow. I'll obviously test to make sure that the Opamp is as it should be and I'll post a pic of the adapter, it looks like a good idea but it'll be nice to see in the flesh so to speak.........


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Both I think, mine were posted out yesterday so should be here tomorrow. I'll obviously test to make sure that the Opamp is as it should be and I'll post a pic of the adapter, it looks like a good idea but it'll be nice to see in the flesh so to speak........._

 

Let us know what you find, I may grab a few of the TO-99's.


----------



## SpudHarris

Well the good news is that these OPA2111AM's are the real deal gold plated legs and all. The little adapters that come with are good when you need a quick way to use a TO99 in a DIP socket, no soldering or Brown Dog required.

 Anyone interested in getting one of these? I already have two on Brown Dogs as spares but can order more. You can have them for same price as me (£6) + shipping. These retail for £39.00 + VAT each 
	

	
	
		
		

		
		
	


	




 If you want them on Brown dogs ready to roll it will be an extra £2.50 (£8.50 total).


 Pic:


----------



## tdn135

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well the good news is that these OPA2111AM's are the real deal gold plated legs and all. The little adapters that come with are good when you need a quick way to use a TO99 in a DIP socket, no soldering or Brown Dog required.

 Anyone interested in getting one of these? I already have two on Brown Dogs as spares but can order more. You can have them for same price as me (£6) + shipping. These retail for £39.00 + VAT each 
	

	
	
		
		

		
		
	


	




 If you want them on Brown dogs ready to roll it will be an extra £2.50 (£8.50 total)._

 

How do they sound Spud? Which opamps would be comparable? Does this one sound better then a AD797BR to you?

 By the way, have you received a genuine pair of AD797BR from ebay?


----------



## SpudHarris

If I'm honest it's horses for courses. In my ibasso P3+ the OPA2111KP is the best Opamp I've heard so assume the AM version will be the same or better, although placebo may play a part due to the AM retailing at 4 x what the KP does..... I will be testing the AM tonight.

 However, in the Fi-Quest the AD797's (AR or BR) are the ones to beat (for me at least). I've given the OPA2111AM a little listen and it is really nice & I haven't played around with any other settings yet like wideband buffers or 4th channel mode. In the Fi-Quest I always seem to end up going back to the AD797's, and likewise the OPA2111 for the P3+.


----------



## ROBSCIX

Now I see how those adapter plates work. Very cool design they just space the legs out for use in DIP8 sockets. I htink I would still rather use a high grade adapter but YMMV. I haven't seen too many with the gold legs they are usually researved for military applications..IIRC.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_in the Fi-Quest the AD797's (AR or BR) are the ones to beat (for me at least)._

 

so what's the diff between A/B to you? running on a linear regulated PSU? majkel says that B kills A, and Jan Meier says that A can be better than B...hummmm.

 IME, OPA2111 had an amazing low end bass but a rather dull upper spectrum.

 I will try the 2*AD797BR chinese ebay module to replace the stock (PCM1793 LPF) LM4562NA on my Firestone Spitfire 2009(running on its "supplier" linear regulated PSU).

 I don't really know what other opamps to try, hah....LT1028A is too pesky and not unity gain stable(which is most likely required being used as a DAC LPF and all)...maybe I'll try my luck w/ 2*AD8597


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_so what's the diff between A/B to you? running on a linear regulated PSU? majkel says that B kills A, and Jan Meier says that A can be better than B...hummmm.

 IME, OPA2111 had an amazing low end bass but a rather dull upper spectrum._

 

Well there is a difference between AD797ARZ and BRZ but it's difficult to put into words. To my ears the BRZ seems slightly fuller and the ARZ slightly brighter, if I'm truthful I can't choose between the two coz I like them both. I don't think the BRZ being almost double the cost of the ARZ is justified by SQ that's for sure.

 The OPA2111AM is a real step up from the KP. I'm listening with this in the Fi-Quest at present with Hi-C buffers in 3 channel mode and I think I'm gonna leave it in a few days to see if I'll drift back to the AD797's, at this point in time I don't know if I will. This chip is amazing........more tomorrow when I've had a few hours with it.


----------



## 12Bass

Thanks for comparing the two AD797s. Just have the ARZs here.... but based on the specifications, it doesn't look like there should be much difference between them. 

 Noticed that Jim Williams didn't think too highly of the OPA1641/42. Haven't given them a critical listen, though they do sound pretty good from what I have heard so far.


----------



## ROBSCIX

Well opinion of opamps also has to do with the rest of the chain. What DAC and other components are being used can affect the overall signature you hear. That is why I only take opinion on opamps so far....I have to test them myself either in a circuit or on a protoboard before I make up my mind one way or another.


----------



## opamp_addict

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_That AD745 looks nice, where can we get those?_

 

You can get those here Svalander Audio AB


----------



## leeperry

anyone compared OPA627B to AD797B?


----------



## SpudHarris

Well I've been using the OPA2111KP for ages in my P3+ so upgraded recently to the AM version which is so worth it. I have also been trying the AM version in my Fi-Quest and with the right buffer set up I really, really love this Opamp. The OPA2111AM is a superb Opamp, IMHO world class.

 All you guys who have grabbed these for different applications please post your findings. For my specific application I have to say I'm happy & then some


----------



## K3cT

Oh noes, more poison to pick up. I'm seriously tempted to build a β22 next so I can forget about this op-amp rolling business already. 
	

	
	
		
		

		
		
	


	




 @leeperry
 Is 627B = 627BP? If that is the case then they sound pretty different. OPA627BP is detailed, tube-like in a sense with good imaging. The 797B is more transparent, more detailed, has better imaging and relatively neutral. A bit laid-back perhaps.


----------



## Spacehead

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well I've been using the OPA2111KP for ages in my P3+ so upgraded recently to the AM version which is so worth it. I have also been trying the AM version in my Fi-Quest and with the right buffer set up I really, really love this Opamp. The OPA2111AM is a superb Opamp, IMHO world class._

 


 Oh, I only have OPA2111KP. I find it somehow light, presentation isn't strong enough. It has poor mids and bass, but good highs. 

 Now I am going to solder OPA2211AIDDA to dip8 socket and try it on my PRR-Szekeres (Tori Amp) 
 I hope it can withstand some load capacitance, driving the IRF510 mosfet. Let's see!


----------



## leeperry

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_@leeperry
 Is 627B = 627BP? If that is the case then they sound pretty different. OPA627BP is detailed, tube-like in a sense with good imaging. The 797B is more transparent, more detailed, has better imaging and relatively neutral. A bit laid-back perhaps._

 

oh ok, thanks for the feedback! I can't picture myself enjoying a TI opamp anyway, they're always too colored to my taste...I've got a major nocebo towards this company I think 
	

	
	
		
		

		
		
	


	




 I'm still awaiting the chinese ebay 2*AD797BR module to put in my Firestone Spitfire DAC...fed w/ a regulated linear ±12V(and toslink to kill computer ground loops), it's gonna be goooooood I'm sure


----------



## Spacehead

eh, I used little damaged dip8 socket and it didn't end up pretty. Looks very awfull but first impression is that I keep this chip for awhile. It is very quiet when I have music paused and has that Burrbrown bass but AD highs. Quite cool. 






 I am sorry for the turn off


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_My preferences are:

 AD797B > OPA1641 > ADA4627-1 
	

	
	
		
		

		
		
	


	


_

 

ahhhhh, I've just been confirmed by Firestone that the Spitfire PCM1793 LPF is compatible w/ AD797 and LT1028(and a few other worthless chips)

 I guess the contenders will be Burson V2/2*AD797BR and 2*LT1028ACN8....talk about history repeating


----------



## SpudHarris

My preferences have changed since discovering the OPA2111AM and will probably change again when/if I find something to better it, not looking at the moment though.


----------



## leeperry

I'm still curious about AD8597...did you try this one? I'll try to locate a bunch of them.


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_My preferences have changed since discovering the OPA2111AM and will probably change again when/if I find something to better it, not looking at the moment though._

 

I would like to try those out also. I always like testing out great TO-99's.


----------



## K3cT

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I'm still curious about AD8597...did you try this one? I'll try to locate a bunch of them._

 

I have these but haven't had the time to test it yet. Right now I'm pretty happy with the decoupled and class-A biased ADA4627-1B. I think I'm an Analog Devices guy after all. 
	

	
	
		
		

		
		
	


	




 @Nigel
 Is there a single version of the 2111AM?


----------



## 12Bass

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_eh, I used little damaged dip8 socket and it didn't end up pretty. Looks very awfull but first impression is that I keep this chip for awhile. It is very quiet when I have music paused and has that Burrbrown bass but AD highs. Quite cool._

 

Yep... nice chip.... though I prefer the sound of two OPA211s... more clarity and channel separation. Don't find these or the other new TI op amps very similar to the veiled character of the older BB OPA2604/2132/2134 parts.

 Haven't tried OPA2111... wasn't too interested after finding the Difet OPA2107 underwhelming. After a little more listening, I'm finding OPA1641 clear, but perhaps a bit thin and grainy. OPA827 sounds warmer, smoother, and rounder in the lows... plus a more "musical" midrange. 

 As for AD8597... if it sounds much like the AD8599 it is sort of warm and not very exciting to listen to. Not that clean/detailed, IMO.


----------



## 12Bass

Funny how hearing little improvements in sound can lead to obsession. Tonight I swapped out the OPA2211A in my Echo Gina 24 for a pair of OPA211s on a BrownDog SOIC adapter. A friend lent me a Delta 1010 so I could transfer a recording project out of Pro Tools and I've been using it for comparing the cards' digital clocks. The 1010's clock seems to help reveal more layers in the mix and clear up the focus in the high frequencies. I previously heard subtle differences with the clock in my RME Digi96/8 as well but wasn't sure which I preferred. Makes me wonder what the Isochrone 10M Atomic Clock would do....


----------



## SpudHarris

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_@Nigel Is there a single version of the 2111AM?_

 

There is indeed. The OPA111AM but as you would imagine they aren't cheap. At the price I'm getting the 2111AM's I don't think I could justify spending £46 on a pair of singles. The BM's are £55 each on Farnell


----------



## ROBSCIX

AFAIK, the OPA111, and 2111's in TO-99 form are considered high grade insturmentation amplifiers but you can also use them for audio work. I have talked with a few and I guess they are widley respected but given their price they are not as common as some of the others we deal with.


----------



## K3cT

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_There is indeed. The OPA111AM but as you would imagine they aren't cheap. At the price I'm getting the 2111AM's I don't think I could justify spending £46 on a pair of singles. The BM's are £55 each on Farnell 
	

	
	
		
		

		
		
	


	


_

 

Holy crap you're right. It's almost 45 bucks a pop.


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_There is indeed. The OPA111AM but as you would imagine they aren't cheap. At the price I'm getting the 2111AM's I don't think I could justify spending £46 on a pair of singles. The BM's are £55 each on Farnell 
	

	
	
		
		

		
		
	


	


_

 

If I like the OPA2111AMs you're sending me, then I may spring for the singles as one of my DACs requires 2 sets of single channel opamps as well as 1 set of dual channels....and that doesn't include the I/V stage which is a set of 14 pin AD841. Right now, I'm running a set of AD797 (Buffer), a set of LME49710HA, and a set of LME49720HA (LPF) and it sounds mighty fine!


----------



## SpudHarris

Well Doug, (+ anyone else who ordered) the Opamps left here today. I had writers cramp filling out all those declarations 
	

	
	
		
		

		
		
	


	




 All sent Airmail so expect them in a week or two.


----------



## ecclesand

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well Doug, (+ anyone else who ordered) the Opamps left here today. I had writers cramp filling out all those declarations 
	

	
	
		
		

		
		
	


	




 All sent Airmail so expect them in a week or two._

 

Thanks, Nigel! Your efforts are much appreciated!


----------



## Spacehead

I got OPA1642 today morning






 I tried to use some time to make a good solder joints on that one. Those are all good and shiny. 

 Quick comparison to OPA2211AIDDA:

 Both op amps have excellent details. OPA1642 has wider soundstage, little annoying mids. Very sharp details. Quite similar to OPA2211. Precision in sound samples is high, I guess excellent THD value (0.00005%) helps. OPA1642 is more laid back than OPA2211. I have heard OPA1641 and this sounds similar as two singles (if I can remember right). I think OPA2211 is better. Little slow bass on this one. Reminds me of OPA2107, very similar low end with it. 
 I think I put that dirty OPA2211 back (which was very close to TPA6120). Or should I try AD8066...


----------



## Spacehead

Then I had to try this:






 AD8066 
 First impression I got was, "Oh, this is balanced" It has the bass, quite heavy actually. But it has details too. Bass isn't as loose like with TI/BB op amps. It is deep and strong, quite penetrating. Mids are crystal clear but lacking something. Highs are little dampened. I think the bass is too much with this chip. I don't find it so enjoyable. Soundstage is quite wide. Very mediocre sounding chip. But a lot better than OPA2132 or jelly bean chips. Vocals sound realistic and not painfully loud as with some poorer op amps. 
 This is quite stable sounding with my PRR-Szekeres amplifier. Driving 100 ohm gate resistor, no conflicts with Mosfet on the other end of the resistor.


----------



## leeperry

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_I have these but haven't had the time to test it yet. Right now I'm pretty happy with the decoupled and class-A biased ADA4627-1B. I think I'm an Analog Devices guy after all. 
	

	
	
		
		

		
		
	


	


_

 

yes, AD make the best chips IMO...Scott Wurcer is a living god!

 I'd be curious if you could run a shootoot between AD8597 and AD797B if you have time 
	

	
	
		
		

		
		
	


	




 I also read a lot of killer feedback on OPA627BP....ah, tempting....but I usually don't like the warmish laid back TI sound.

 I think I'll order a Burson V2, at least I know what I'm getting


----------



## ROBSCIX

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Well Doug, (+ anyone else who ordered) the Opamps left here today. I had writers cramp filling out all those declarations 
	

	
	
		
		

		
		
	


	




 All sent Airmail so expect them in a week or two._

 

Yes, Thanks for your time and effort. I will keep you posted.


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_If I like the OPA2111AMs you're sending me, then I may spring for the singles as one of my DACs requires 2 sets of single channel opamps as well as 1 set of dual channels....and that doesn't include the I/V stage which is a set of 14 pin AD841. Right now, I'm running a set of AD797 (Buffer), a set of LME49710HA, and a set of LME49720HA (LPF) and it sounds mighty fine!_

 

I usually prefer singles many times in favor of duals depending on the chip. 
 If you get a line on some OPA111's TO-99 drop me a line and perhaps we can get a better rate if we pool our cash and buy a few more.
 Your 14pin AD841, is it possible to adapt that to a more common opamp footprint?


----------



## leeperry

hehe, Jim Williams doesn't care too much for 627, and if 827 is an improved 627...then I won't be wasting my time and cash: Burr-Brown OPA627BP's? - Gearslutz.com

 I actually have some LT1357 I forgot about, he always says that these are very good..time to try them


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I usually prefer singles many times in favor of duals depending on the chip. 
 If you get a line on some OPA111's TO-99 drop me a line and perhaps we can get a better rate if we pool our cash and buy a few more.
 Your 14pin AD841, is it possible to adapt that to a more common opamp footprint?_

 

I'm sure I could adapt it as there are only 8 of the 14 pins that are being used and those 8 pins match a standard DIP8 single channel layout. I probably won't try until I can secure a couple of backup AD841s. I can find them, however, most places won't sell them unless you're buying a bunch.


----------



## 12Bass

Some more thoughts from JW: Gearslutz.com - View Single Post - TL072cp

 BTW, for those who are not familiar with him, he builds and modifies high end audio recording equipment.


----------



## leeperry

yes, he seems to be a reference to Andrea too...anyone tried LT1357? I think I tried LT1358 and wasn't too impressed, but it was on a crappy soundcard and it was a dual. I'll also try LT1122AC and LT1128C.

 anyway, I was told by Firestone that I could use whatever the hell I want in the Spitfire as PCM1793 LPF...it wouldn't matter whether the opamps were unity gain stable, and they actually advise to use LT1028 at page 20 of the PCM1794 datasheet...they got zillions of OPA chips and yet advise LT1028, go figure


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Some more thoughts from JW: Gearslutz.com - View Single Post - TL072cp

 BTW, for those who are not familiar with him, he builds and modifies high end audio recording equipment._

 

Interesting read. Although I would say his application from some of the OPA's may be a bit different if he is using them for input sections. The idea behind his application would still be good sound that is as uncolored as possible. I was getting the idea he was testing them in an input section.
 There are some people out there that have a good handle on opamps for audio use. I have stacks of printed PDf's and design guides to get ideas from some of these guys. I find the guys that have been doing recording work for along time or work with recording gear usually have some great ideas and opinions to impart.

 I might be wrong but didn't you mention that you do recording also 12bass?


----------



## 12Bass

Some recording, yes.... currently mixing an album for some friends....


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Some recording, yes.... currently mixing an album for some friends...._

 

I hear ya. I always have buddies asking me to record them. I have been recording for many years now though so I enjoy having projects to work on.
 One of those love/hate things.


----------



## Pacha

What other opamps is there of the sort of LME49720HA LM4562HA TO-99?
 Anything to recommand? Anythink "better" of this kind?


----------



## ROBSCIX

There are many TO-99 opamps out there.
 "better" is subjective so it would depend on what you are looking for.


----------



## Pacha

I am looking for a neutral and detailed opamp as LME49720HA (LM4562HA) are described.


----------



## ROBSCIX

Try the dual LME49710HA, I find they sound better then the dual channel 720's.
 So it might be what you're looking for.


----------



## Spacehead

after testing a bunch of new op amps, I am back with AD8620 on ground channel and AD8599 on left and right. Amplifier is Tori Amp with IRF510x2 + BD139 on ground
 Perfect combination of the best chips. Smooth, energetic, non-fatiguing, bright, sweet, accurate, warm, pleasant, peaceful, noise-free, articulated, etc. 
 But maybe a slightly colored ?


----------



## ROBSCIX

Both the AD8620 and AD8599 are favorites of mine...and many others around here I think. They can provide some great sound in many circuits.


----------



## Sorian

Whew, finally got my account activated/authorized. Have been waiting for days to be able to ask a question in this thread.

 My HT Omega Claro Plus sound card died on me not too long ago and I'm getting it replaced with the Claro Halo.

 I'd like to swap the opamps, as I've heard the ones in the Halo are pretty low quality (they are something along the lines of JRC4580, I believe). I emailed HT Omega to see what the had to say, and they recommended OPA2132P(TI). But I figured I would ask a board of informed members before picking any.

 So my question is.. what would be the best opamps for the Claro Halo? My headphones are HD 595s, and z-5500 speakers (not the best setup, but all I can afford), and I want a sound that is pretty much the jack of all trades, good at everything, if possible.

 Also, where would be the best place to get the opamps for relatively cheap, once I decide which ones?

 Thanks,
 -Sorian


----------



## 12Bass

There is no universal "best" op amp. What sounds "best" depends on the circuit and your preferences. 

 That said, I've found the OPA2132 somewhat warm/veiled, and lacking in detail, though a step up from cheaper chips. An OPA2211A or a pair of OPA211s or OPA827s on a BrownDog adapter might be worth a try. Maybe read through this thread to get an idea of peoples' thoughts on various chips and go from there.

 Digi-Key and Mouser are worth checking out....


----------



## ROBSCIX

@Sorian, you can go with the 2132, or possible the OPA2134 They will have tubby bass and glossy highs..the typical BurrBrown sound as some call it.
 I would say the best hting to do is to talk with other members that own that card, in this forum or others and see what they have to say about which units sound good on that card.
 12Bass is perfectly correct. There is really no best opamp, just different sonic flavors.

 The trick is to find flavors you like and that work good for your gear.

 Where are you located? It would help if peopel are going to point you to a reputable dealer.


----------



## Sorian

I'm in the the northwest. And I was reading through the thread on the Claro itself, but it didn't exactly help me all that much, and I figured I would rather post here than in a thread that has been dead for a couple months. Anyways, I honestly don't have a clue what type of sound I'm looking for. I've never been one to be able to clearly identify the different types of sound. I just appreciate the good stuff. My old card, the Claro Plus, uses AD8620BR, which I guess I could say I really liked, as they were the best I've ever had. 

 My only worry is that I'll end up having to try out tons of different opamps to find a good one, which could cost quite a bit of money, and it would probably be hard to pick a favorite. So I'm just looking for some of the best quality/most reputable ones, I guess.


----------



## qusp

have you still got the AD8620BR? pretty good chip. that would be a cheap experiment installing them in there. I would also mention OPA2211 or 2 x OPA827. also 2 x AD797, but these are a bit tricky to get right. how much supply voltage have you got?


----------



## Sorian

The AD8620BR is what came on the Claro +, which I had to send back/was broken. And I honestly don't know what my supply voltage is on this PC. Brother put it together years ago and I've never taken too much time to look into what it has inside.


----------



## qusp

well the supply voltage is very important if you want to pick some suitable chips, some of the best ones are not happy with lowish voltages. but its the supply voltage of the card thats important, not the computer. some cards access the main PSU for a higher current, some just take the standard 5 or 12v from the PCI bus


----------



## 12Bass

And some chips are not happy above 5 V (OPA2365) or 12 V (AD8066, AD8397). My guess is that power rails in many soundcards would be in the +/- 12V range. This can generally be tested if one is extremely careful with a multimeter (look between case ground and pins 4 and 8 on the op amp). The general point is that it takes some research, including reading the spec sheets, to find an optimal match for your application.


----------



## qusp

yeah I edited my post above to say exactly that. its probably 12 I reckon since its not strictly a low end card


----------



## LuciferX

From an old email

  Quote:


 
 I sent a email to HT Omega:


 Q: *LME49860 - 44V Dual High Performance, High Fidelity Audio Operational Amplifier <<< Will this OPAMPS work with the halo claro? I Heard that it needs around 15v to sound at its best, which is probably quite above the claro halo voltage. What is the maximium voltage that the card support?*

 A: _As you checked power supply, it supports +/2.5V to +/22V_







_*Claro halo use 12V for power supply voltage to opamp*. 
 Therefore, you can use that opamp without power supply problem.

 If you need more information, please let me know.

 Thanks.
 Sincerely,
 HT OMEGA – Tech Support _


----------



## ROBSCIX

Quote:


  Originally Posted by *Sorian* /img/forum/go_quote.gif 
_The AD8620BR is what came on the Claro +, which I had to send back/was broken. And I honestly don't know what my supply voltage is on this PC. Brother put it together years ago and I've never taken too much time to look into what it has inside._

 

OK, Since you are not sure what type of sound you are looking for let's try something different. What is wrong with the sound you have now on this card?


----------



## Shatter

Hello

 I have an Asus Xonar DS, with a JRC5532 opamp for front/headphone output.

 The headphones I'm using are Philips SHP9000s (32 ohm, but otherwise inefficient and very finicky with amps, a meier corda arietta drives them beautifully, they sound about on par with HD595, but I'm not willing to pay that much)

 The trouble i'm having, other than the low volume, while driving the headphones directly from the soundcard, is a kind of "volume drop" for a moment after any bass beat, drum hit, stuff like that.

 Could I solve that by changing an opamp? Is it likely to be the opamp or the capacitors? The opamp is DIP8 socketed, so if I'd know that changing it would solve smth, I'd try that first. But with what? Also, would another opamp solve the volume problem as well (with no other circuit modifications)?

 I've seen some knowledgeable electronists here, hope someone has in idea. Thanks.


----------



## ROBSCIX

@Shatter, do you have the SVM enabled? As it can produce a similar effect, dropping loud notes. The circuit just may not have enough power to drive your cans. You can try and install a higher power output opamp.


----------



## leeperry

so where's the love for LT1028ACN8? it really is as good as RS says IMHO: REVIEW: Ray Samuels Emmeline HR-2 - SGHeadphones
  Quote:


 As Mr. Samuels once remarked, the LT1028 is like putting sugar all over your sound. It has a very liquid, sweet, and warm midrange that exhibits sharp bass and treble roll off. Unlike the Analog Devices op-amps, it is not dark. In fact, low level details flow through with greater clarity and definition. 
 

I don't think even Andrea would manage to make me ditch it


----------



## Shatter

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_@Shatter, do you have the SVM enabled? As it can produce a similar effect, dropping loud notes. The circuit just may not have enough power to drive your cans. You can try and install a higher power output opamp._

 

What is SVM?


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_so where's the love for LT1028ACN8? it really is as good as RS says IMHO: REVIEW: Ray Samuels Emmeline HR-2 - SGHeadphones

 I don't think even Andrea would manage to make me ditch it 
	

	
	
		
		

		
		
	


	


_

 

I think the 1028 is a nice chip but I use IEM's a lot and the snap when turning of my amps with this chip installed scares the crap out of me. I have a few versions CN8 (DIP) and twin SOIC etc....and they are all the same


----------



## Theta

Quick question for you OpAmp guys...

 My Aune DAC/Amp is supplied with a 24V supply, and I've rolled the OpAmps in the unit as follows:

 Buffer OpAmp: OPA2604 --> AD8066
 Headphone OpAmp: OPA2134 --> OPA2107

 Question is, can I run the AD8066 at the 24V without worrying? The chip tolerance is +5V / +24V, and I'm not sure how the Aune is built regarding putting voltage to the OpAmps.

 I'm digging the clarity of the AD8066 in the buffer right now, better than anything else in my stable (have not tried OPA627 on a BrownDog yet).

 Thanks!


----------



## majkel

24V is OK for the AD8066. I'd rather put the AD8599 after the OPA2604.


----------



## leeperry

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I think the 1028 is a nice chip but I use IEM's a lot and the snap when turning of my amps with this chip installed scares the crap out of me. I have a few versions CN8 (DIP) and twin SOIC etc....and they are all the same 
	

	
	
		
		

		
		
	


	


_

 

well, apparently LT1028 is a "negative amplifier" from what the Firestone tech support told me: http://www.head-fi.org/forums/6456476-post156.html

 maybe you can add an audio switch, and turn if off before turning your amp off..but serious gear should have an anti-pop mechanism at power on/off

 well, the SS is less 3D than AD797B, but the low end bass response is fantastic...and the SS is as "holographic" as can be 
	

	
	
		
		

		
		
	


	




 I've never tried a tube amp, but that's how I'd imagine their SS would be like on good quality ones...very holographic, highly detailed and colored simultaneously.

 my fav combo is still AD797B as DAC LPF+LT1028AC for headphones amp...but I've found a DAC that's happy w/ LT1028 so it's gonna stay like this for now 
	

	
	
		
		

		
		
	


	




 I will try AD797BR/Burson V2 in the next coming days.


----------



## ROBSCIX

Quote:


  Originally Posted by *Shatter* /img/forum/go_quote.gif 
_What is SVM?_

 

Smart Volume Managment...the idea and setting varies from card to card but this setting can cause the issues you are describing.


----------



## 12Bass

Yeah... sounds like some sort of compression/limiting.


----------



## Shatter

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Yeah... sounds like some sort of compression/limiting._

 

That's EXACTLY how it sounds (i've done some audio processing back in the day), but i never thought someone would implement that in the driver (sounds silly, at least at the consumer level). There's a setting called SVN (smart volume normalization?), maybe that's it. 

 I'll try changing the opamp anyway, thanks. By the way, do you know of one that would be a drop-in replacement for JRC5532 (is it the one used in the Benchmark DAC1?) I've seen references to that chip here, maybe you know something that would fix the "scooped out" midrange problem i'm having.

 LE: Yes, svn->off fixed most of the "silence after loud sequence" problem. Thanks a lot.


----------



## ROBSCIX

Thats the one...SVN. Glad to hear that was the problem and you fixed it.
 You can still change out the opamp to improve the sound quality.
 The 5532 is probably the most used opamps in audio electronics. It has been used in everything from professional grade studio mixers to soundcards and everything in between.
 Scooped out mids? are you sure your card is set up properly?
 This card should sound rather "flat" if you have no effects enabled. IIRC, it measures quite flat in frequency response tests.
 How is your card set up?


----------



## 12Bass

Made up this Frankenstein quad op amp for an A/DA flanger which I built recently:







 OPA1642 for op amps A & D, and OPA2211A for B & C.


----------



## ROBSCIX

Very cool. Are you using the flanger for guitar or just for recording effects?


----------



## 12Bass

Hmmm.... lately it has been effective at scrambling my brain with soaring and falling swooshing sounds. I say that because the other night I was hearing flanged music at the pub (which wasn't actually flanged). Suspect neural adaptation was to blame....

 When it is completed, it will be used as a bass/guitar effect.


----------



## ROBSCIX

Flanger can give some decent effect for guitars. I have a bunch of hardware effects and softare flangers. Not that I use them all that much though...

 You built this one from scratch? Many effects and recording gear just use plain generic opamps such as 5532..etc. A simple upgrade can give some great sonic gains in recording gear.


----------



## 12Bass

Built the SAD1024A version of the A/DA flanger, as I had a chip around from a Radio Shack project I built as a child. Those old chips sell for $50 plus on eBay!


----------



## ROBSCIX

@Spud, you made a great find IMO. I am having a great time with these new OPA2111AM's.


----------



## 12Bass

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_@Spud, you made a great find IMO. I am having a great time with these new OPA2111AM's._

 

Haven't tried any of the metal can op amps. How would you characterize the sound?


----------



## SpudHarris

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_@Spud, you made a great find IMO. I am having a great time with these new OPA2111AM's._

 

Thanks 
	

	
	
		
		

		
		
	


	




 Let me know if you need more. I contacted my guy and he has some left. I'm getting a few more just because I love them and I'll never see them at that price again ever.


----------



## ecclesand

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_@Spud, you made a great find IMO. I am having a great time with these new OPA2111AM's._

 

Good to hear...I'm very excited to get my set.

 On a side note...I just soldered up some OBCA AD744s and dropped them in my DAC. WHOA! Very nice....it feels like I'm actually in the music if that makes any sense.


----------



## SpudHarris

Haven't used my OBCA AD744's for ages. When I get my Maxxed out Fi-Quest back I'll give them another go.....


----------



## LuciferX

I need a good AD DIP8 (dual) opamp just for try it in my Claro Halo, actually I have installed 4xOPA2107AP by TI. Advice? (Looking for something with good details and ss, great bass, but not "metallic" or "harsh" sound)


----------



## SpudHarris

@ LuciferX - How about AD8620 / AD712 / AD823 (Graham Slee Solo uses this) or singles on an adapter like AD797........


----------



## leeperry

. oops wrong thread


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Haven't tried any of the metal can op amps. How would you characterize the sound?_

 

I have a pile of Metal can opamps, I usually try to test those out of any opamps series. On my current setup, I found them very warm without loss of detail and they sound very alive, not cold or sterile. The best word I can use to describe them is they sound very "analog". I have difficulty describing what I hear.


----------



## Spacehead

Should I try AD8672 on my buffered amplifier? The 10 mA output current limit bothers me. And I have 5 mA Class A bias.

 Edit: Just checked, It was 30 mA short circuit @ 15V . So it should work very well.


----------



## Mad Max

I've been playing around with a few opamps in my Minibox-E+ and Audio-gd Compass, and I thought I'd post my observations. This is just how they sound on _my_ equipment, so you may not get the same results on yours.
 If I tried out opamps in my DAC, I'd use the line-out to my portable because it is significantly more transparent and less forgiving than my DAC's built-in amp.

 ADA4627-1B/A: The first aspects of these opamps that immediately caught my attention are the neutrality, air, and soundstage. This is the airiest opamp I've heard yet and the soundstage has such definition that I've never heard before in anything. Every sound from the far left to the far right has incredibly well-defined edges to it, everything to the left or right away from the center feels like it takes a step forward, even though it hasn't, I'm not sure how to put it into words. Everything is so crisp and sharp without sounding too much so. I love how percussion attacks are so sharp, crisp, and defined, perhaps ever so slightly short of life-like. Accompanying voices in music have better presence yet without competing with the lead melody. This opamp is also very smooth-sounding, not smeared. 4627-1A is ever so slightly less extended at the top than the B version and is a lukewarm whereas the B version is totally neutral. The sound is very flat all throughout, even in the bass, giving bass notes a bit of that awesome fortitude I hear with my RE-252 earphones. They're very nuanced and spacious in sound and so neutral, I'm not sure how to describe them as they have no particular character. Usually, with all the other opamps, there are slight dip(s) in the FR that make the lows, mids, and highs sound like they are grouped together, like the slight dip between the upper bass and lower mids, more or less for example. I don't hear that at all with 4627-1, everything is flush together. LME49710 is the only other opamp that sounds like this, except its mids are a touch boosted. This AD chip is also the first opamp that I like better than Earth in my Compass DAC, however, it does not have Earth's holographic soundstage (I figure this might interest any gamers reading this). I can't really comment a lot on depth of soundstage because I can't perceive it that well - I just know my Compass has [some] depth and my ipod doesn't at all, lol. I'm really loving this little chip!

 AD797B: This one is pleasantly colored and very smooth and airy. It is very detailed with slightly rounded mids and punchy, tuneful bass - this is the bassiest opamp I've heard yet. The midrange brings to mind the color orange-red. The highs are somehwat rolled-off yet still nuanced and airy without being soft. I love this fun-sounding chip with my SR325is - really wonderful synergy there. In my portable amp it sounds very good but is more rolled off in the highs and lows with more forward mids and less detailed than in my desktop DAC, a noticable but not massive difference. I'd say this one is about on par with the HDAMs overall. I really like vocals on this one - there's some nice emotion to them.

 ADA4857-1: This is a very interesting opamp. It has a slight hint of a "green" color to it. It has very good overall refinement, just a hair or two short of as good as 797/4627-1, slightly less detail, and very, very clean and smooth. More spacious sounding than the other opamps and slightly sweet, a bit smoother actually. This one is growing on me more and more. It is most similar to 4627-1, but just a pinch less of almost everything and about as airy.

 OPA1641: Smooth and clean with somewhat tuneful bass. It is close to neutral, I think the upper mids are a pinch laid-back. Not quite on par with the previously mentioned opamps but I like this one better than TLE2141A which is the one I had been using for some time in my Minibox-E+ before this latest round of opamps (I was liking 2141 better at first, but as of lately, 1641 is sounding better). The upper highs and lower bass have better presence than 2141A and the mids are smoother and just as nuanced with slightly better definition throughout the spectrum. Extension at the extremes is slightly better. Both OPA1641 and TLE2141A are a bit soft-sounding and neither is on par with 4857-1, 4627-1, and 797 overall.


----------



## devast

Welcome to the neutral club with your ada4627-1BRZ 
	

	
	
		
		

		
			




 I've been using it for months now, the only chips i'd like to try out is the ad797 and the lt1028. Still, as i'm totally satisfied with my current setup i don't think i'll get those.


----------



## Spacehead

This one is very detailed. Quite narrow soundstage. Bass is neutral. Gives zero DC offset which is excellent. Very low distortion. Less colored. Closer to AD8599 than AD8620. Maybe better sounding than AD8620. Like between them. Not as warm as AD8599 but not as cold AD8620. Transitions are smooth. Pretty fine sounding really! I keep this for a while. 
 I have Walt Jung's diamond buffers on outputs and op amp is class a biased. Ground channel has OPA2211 and OPA633. Superb combination.


----------



## Mad Max

Any of you guys ever compared AD8599 to ADA4841-1?


----------



## 12Bass

IMO, AD8599 is sort of dark/warm sounding, and not best suited for detail retrieval.


----------



## leeperry

very nice review Max Max! anyone compared the ADA4627-1B SS against AD797B on wide SS headphones?

 I've got a hard time believing that AD/Scott Wurcer didn't manage to overdo themselves since the 797(10 years ago or so?)....OTOH I don't really see what could possibly be improved 
	

	
	
		
		

		
		
	


	




 anyway, I've ordered one more AD797BR module from ebay, it's so damn convenient...and sounds so damn good 
	

	
	
		
		

		
		
	


	








 they give exactly the same sound as the AD797BN I used to have, they're definitely not fake! OTOH, one of the pins of the bottom chip was poorly soldered...but very easy to "fix".

 also, her adapters seem to offer a far better contact than the browndogs.

 PRaT is lower than on LT1028A, the SS on the 1028 is truly "holographic"(really tubey?) but very limited....the AD797B SS seems to be able to present sound in the X-Z planes w/o any limits...the audio is as 3D as can get.


----------



## leeperry

I just received LT1122ACN8/LT1128CN8/LT1357CN8...very curious to hear why Jim Williams is so fund of 1357


----------



## 12Bass

JW seems to like transparency above other considerations. So, that may not match your own preferences.


----------



## leeperry

well, I wouldn't really call AD797B "colored to death", LT1028A on the other end definitely is(and also far less detailed than 797)...anyway, I'll try it in a bit


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_JW seems to like transparency above other considerations. So, that may not match your own preferences._

 

I think many consider that transparency the lack of "color" or the ability to just allow the sound of the amp to come through with no additional influences from the opamps. I think many of use are looking for that and from a purist point of view we should all be looking for that however, some like coloring as it helps with synergy for certain systems.

 What do you look for 12bass, transparency or some coloring?
 Just a question to hear different opinions.


----------



## leeperry

just put back LT1028A....now that's good sound, PRaT is just nuts..SS is completely different from AD797B.

 Ray Samuels says that it adds sugar all over your audio, hard to deny 
	

	
	
		
		

		
		
	


	




 I'll roll LT1357 in a bit...and I've ordered some ADA4627-1BRZ/AD8597ARZ

*PS:* they should definitely sell LT1028A for +$60


----------



## Mad Max

797B has the edge against 4627-1B as far as soundstage. Or that's what my Minibox-E+ + AD700 showed me.

 I have 1357, I got tired of it after a while. I'd say it is more or less on par with 1363 and has bright highs with warm, slightly energetic mids and rounded bass in my gear - very colored and fun. The first time I popped it in it had Grado-like energy with AD700 in the mids, but it lost some of the energy with use. I haven't used it again in a long time.


----------



## Mad Max

*double post*

 Edit: How was it again one does class A biasing of mono opamps? And output-bypass?

 Edit2: So it's a 2.2k to 10k resistor between pins 6 & 7 for Class A and join pin 5 to 6 (on certain opamps) for output bypass. Thanks, ecclesand.


----------



## leeperry

well, the SS on 1028A is far wider than on 797B, but it's also less versatile...it's kind of triangle shaped(a huge triangle, though 
	

	
	
		
		

		
			





), where 797B would be like a big rectangle, but not as large.

 anyway, the sound is a lot "thicker" and impressive on 1028A, and the SS a lot more versatile on 797B...they make for a perfect combo IMHO, 797B on DAC stage and 1028 for final buffer


----------



## ecclesand

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_*double post*

 Edit: How was it again one does class A biasing of mono opamps? And output-bypass?_

 

http://www.head-fi.org/forums/f6/opa...ml#post6012420

 Use a 2.2k or higher resistor for class a. I have used 2.2k up to 10k.


----------



## Mad Max

What does that resistor do, exactly? How do you know which value between 2.2k to 10k is best or is it experimentally determined?

 Edit: I see AD744 there is special because of pin 5 being for "compensation." What is the compensation? None of the other opamps I have have this according to their datasheets, and for 2141A pin 5 is some kind of offset. So pin 5 having some kind of use makes the output bypass mod possible?


----------



## 12Bass

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I think many consider that transparency the lack of "color" or the ability to just allow the sound of the amp to come through with no additional influences from the opamps. I think many of use are looking for that and from a purist point of view we should all be looking for that however, some like coloring as it helps with synergy for certain systems.

 What do you look for 12bass, transparency or some coloring?
 Just a question to hear different opinions._

 

Difficult to put into words. I like the idea of transparency... or parts which don't add any coloration to the signal. On the other hand, some components add a pleasing coloration... so it depends. Also varies based upon the application. For musical use, I tend to go more for a sound that accentuates the tonality of the instruments, while hi-fi applications lean more toward clarity and minimal coloration.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Difficult to put into words. I like the idea of transparency... or parts which don't add any coloration to the signal. On the other hand, some components add a pleasing coloration... so it depends. Also varies based upon the application. For musical use, I tend to go more for a sound that accentuates the tonality of the instruments, while hi-fi applications lean more toward clarity and minimal coloration. 
	

	
	
		
		

		
		
	


	


_

 

I guess it just depends on what you after. Some people like coloring and others don't.


----------



## diditmyself

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_What does that resistor do, exactly? How do you know which value between 2.2k to 10k is best or is it experimentally determined?

 Edit: I see AD744 there is special because of pin 5 being for "compensation." What is the compensation? None of the other opamps I have have this according to their datasheets, and for 2141A pin 5 is some kind of offset. So pin 5 having some kind of use makes the output bypass mod possible?_

 

Pin 5 on AD744 is a compensation pin. You're supposed to connect a capacitor from this pin to ground or one of the supply rails. The exact value depends on the circuit and what bandwidth you're after... but this pin is a direct output from the voltage amplification stage and can be used to bypass the internal output stage and use an external output stage instead.

 Since the VAS in AD744 is single end it can't operate in anything but class A. There's no need for further Class A biasing when used as described above. A resistor from neg rail to pin 5 does nothing but mock up the circuit.

 In general ClassA biasing of opamps might be theoretically appealing, but I don't think it holds up in a blind test. The resistor (or better a constant current source) is choosen to class A bias the output stage to a point where you're certain it will operate in single end class A at all levels.


----------



## Spacehead

Now listening AD8397 directly in a tweaked cmoy-core. I added 10 ohm output resistors and ferrite beads. Dc offset is 8 mV per channel. 

 AD8397 sounds quite delicious, like orange, nice to rip open and then enjoy bitter sweetness. But actually it is too sweet and oscillates very easily. 

 I can't yet tell final verdict because there is some oscillations. 

 When I used this chip on my buffered 100% stable amp, there was less sweetness and more sharpness, but good transitions and bass. Highs are recessed.


----------



## 12Bass

What sort of supply bypassing are you using with the AD8397?


----------



## Spacehead

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_What sort of supply bypassing are you using with the AD8397?_

 

In that poorer cmoy-core I had 0.1 uF from -V to G and +V to G 
 multilayer ceramic capacitors

 In this better buffered cmoy-core I have one Panasonic FC from +V to -V and it seems to keep things stable , as well as being buffered, getting the load of from op amp. (or is 50 ohm resistor too low between WJ buffer and op amp) 

 I was just about to post that I really like this AD8397. It gives life to music and sounds. 


 And btw. I just try and test every possible option to get things working. I don't understand that much, but I read a lot. 
 I have balanced inputs in this current amplifier, so offset is low and stability improves.


----------



## Mad Max

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_Pin 5 on AD744 is a compensation pin. You're supposed to connect a capacitor from this pin to ground or one of the supply rails. The exact value depends on the circuit and what bandwidth you're after... but this pin is a direct output from the voltage amplification stage and can be used to bypass the internal output stage and use an external output stage instead.

 Since the VAS in AD744 is single end it can't operate in anything but class A. There's no need for further Class A biasing when used as described above. A resistor from neg rail to pin 5 does nothing but mock up the circuit.

 In general ClassA biasing of opamps might be theoretically appealing, but I don't think it holds up in a blind test. The resistor (or better a constant current source) is choosen to class A bias the output stage to a point where you're certain it will operate in single end class A at all levels._

 

So Class A biasing doesn't yield any sonic benefit? Just makes the opamp run a little hotter then, from what I've read. I decided to ask since AD744 and TLE2141A are recommended (744 in the past) for the iBasso D10, either with output bypass _and_ Class A. I haven't tried any of this though, just the opamps as stock.

 [rant]Man, I looove AD744's midrange. Something about it sounds sooo right compared to all the others, but I can't put my finger on it.[/rant]


----------



## kuben

Is there a big SQ difference between AD797 ANZ and AR?


----------



## kumaiti

Double post, sorry.


----------



## kumaiti

OMG, 157 pages.


 Would any kind soul recommend an opamp with a "bassy" sound signature that is compatible with the Essence STX/ST? 
 I have a bass-light headphone and I am considering to get some opamps for the Essence to make up for that.

 Or at least a more "newbie-friedly" article about these things? This thread is almost like greek to me...


 Thanks!


----------



## kumaiti

How useful are these?

 RC4558P dual opamp. Texas Instruments, 1992 date code
 RC4559N Dual High Performance Opamp Raytheon 1983 date code
 LM1458N Dual opamp National Semiconductor
 LM833 8 Pin DIP dual opamp National Semiconductor
 TL072CP Dual opamps Texas Instrument
 JRC4558D dual opamp
 Burr Brown OPA2134 opamp CJOD
 NE5532N Dual Low-Noise High-Speed Audio Operational Amplifier Fairchild Semiconductor


 Found this "kit" on an online store. Worth getting as a "starter kit" or is it just a bunch of garbage?


----------



## 12Bass

Out of those, the OPA2134 and NE5532 are the only ones which are remotely "hi fi". The others are older designs, mostly from the 70s.


----------



## kuben

What determines what kind of chip will be compatible with my board? Which technical specs would determine that?


----------



## G.Trenchev

Could you tell me better alternatives of TL081 ? 
 I tried NE5534 and NE5532,and I don't like them.The only opamp I know to look for is OPA2134 now.I can't find one for the moment.


----------



## Mad Max

Quote:


  Originally Posted by *kumaiti* /img/forum/go_quote.gif 
_...
 Would any kind soul recommend an opamp with a "bassy" sound signature that is compatible with the Essence STX/ST? 
 ..._

 

The Earth HDAM, AD797, AD8065
 One of the first two preferably, I guess.


  Quote:


  Originally Posted by *kuben* /img/forum/go_quote.gif 
_What determines what kind of chip will be compatible with my board? Which technical specs would determine that?_

 

Gain, voltage swing, and supplied power, I think.

 If your board's voltage swing is higher than the chip can support, it will get fried. If the gain isn't the right one or the chip isn't unity-gain stable, it may not sound right, I think. Then the chip has to be able to receive sufficient power, though I am not sure.


 Also, how would 2132 change if stacked? Will it sound the same?


----------



## Spacehead

I got ADA4898-1YRDZ and ADA4627-1ARZ today. I am now building a custom amplifier for them because I don't have any yet that would work with singles. I will use dc servo instead of input cap.


----------



## Spacehead

These babies can drive headphones (32 ohm HD438) directly! 






 I was succesfull building a amplifier for singles with dc servo. OPA1642 is very accurate as servo op amp. In the ground I have Intersil HA3-5002 and AD8672. 










 This is now after heavy tweaking pretty stable, and pretty quiet with 47 ohm output resistors and gain 2. 1K ohm resistor in feedback loop and 470 ohm into inverting input ground. ADA4898-1 datasheet recommends low value resistor and proper supply bypassing. There is 0.1 uF and 10 uF Rybucon bypass caps. I am using two 9V batteries in series to power these, there is little over 1000 uF supply capacitance, which is barely enough.

 To the sound of these. I have now listened a while and can tell that how the heck can op amps sound this lovely, maybe it is the fact that I tweaked so hard and now I am getting rewarding sensation. But anyways, these have excellent warmth and soundstage is very very wide, I have never really experienced single op amps, they really widen the stage. Some sounds distort a little, but that maybe because I have empty batteries and maybe they oscillate a bit, being fast op amps. But anyway these are instantly my favorites. 
 What I am most amazed is the driving capability. These drive my phones very effortlessly. Only TPA6120A has been better from op amps I have tried. I think my discrete buffers sound too harsh to be really enjoyable. These have delicate and sensitive sound, very easy to listen. Of course I am now very happy from successful build. This is true DIY moment!

 Edit: 
 I got rid of the distortion. It was some bad caps in my dc servo. I will continue tweaking, but it is very good for now.


----------



## ROBSCIX

I had a buddy from another forum completely rebuild the entire output section of his X-fi. You reminded me of that when I seen your circuit above..


----------



## Spacehead

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I had a buddy from another forum completely rebuild the entire output section of his X-fi. You reminded me of that when I seen your circuit above.._

 

nice, I don't have yet such skills. I have done more harm to my X-FI than good. There is slight hiss now, I guess it is grounding issue, dc coupling caps through holes got away and now there is no connection to ground. I guess I could route those to other ground spot. 

 But I am very happy that I got the DC servo working, it was quite a mysterious thing to me before. 
 Now I just need to make a proper power supply, this current one has hum. 

 BTW. Can cheap ceramic caps cause distortion when used as bypass caps? I used 2 of them for each op amp, but bypassed them with 10 uF electrolytic and 0.1 uF polystyrene caps. All my op amps (4) and buffer (1) can take 30V at least, so I am using slightly higher voltage, 25.6V. Now these AD4898-1 should be able to put out about 40 mA linear current into 150 ohm, and short circuit 150 mA, so I guess they can put enough to 32 ohm (+47 ohm output resistor). I had to try these until I can put them into PPAv2 which PCB should come next week. I have seen dreams about PPAv2!!


----------



## buz

I am eagerly awaiting my HA NG98 but in the mean time, I figured I could order some opamps to play around with over easter. To be honest, I got a little confused. The DAC/AMP uses two OPA2604 for the headphone and two and two BUF627 for the line out I believe. 

 Does that mean, I need two brown dogs and 4 AD797? Damn that's expensive


----------



## buz

I am eagerly awaiting my HA NG98 but in the mean time, I figured I could order some opamps to play around with over easter. To be honest, I got a little confused. The DAC/AMP uses two OPA2604 for the headphone and two and two BUF627 for the line out I believe. 

 Does that mean, I need two brown dogs and 4 AD797? Damn that's expensive


----------



## qusp

actually OPA2604 os a dual opamp, you need 4 797 (these are single channel chips) just to replicate that and 797 are what we call 'cranky' opamps, so there is no guarantee they will work properly in your circuit anyway. there is no such thing as BUF627 either you mean OPA627 or you mean BUF634, which one is it?


----------



## ecclesand

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_actually OPA2604 os a dual opamp, you need 4 797 (these are single channel chips) just to replicate that and 797 are what we call 'cranky' opamps, so there is no guarantee they will work properly in your circuit anyway. there is no such thing as BUF627 either you mean OPA627 or you mean BUF634, which one is it?_

 

It's BUF634...I have one of those HA INFO NG98 dac/amps too.


----------



## buz

Ah very good, someone who might have some experience with opamp rolling there. Any recommendations, ecclesand?


----------



## ecclesand

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_Ah very good, someone who might have some experience with opamp rolling there. Any recommendations, ecclesand?_

 

I did the HiC mod to the BUF634 which improved the sound and then replaced both OPA2604 opamps with ADA4627s modules I built. I also enjoyed the LME49720HA opamps and the LT1364 in both positions.


----------



## ROBSCIX

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_nice, I don't have yet such skills. I have done more harm to my X-FI than good. There is slight hiss now, I guess it is grounding issue, dc coupling caps through holes got away and now there is no connection to ground. I guess I could route those to other ground spot. 

 But I am very happy that I got the DC servo working, it was quite a mysterious thing to me before. 
 Now I just need to make a proper power supply, this current one has hum. 

 BTW. Can cheap ceramic caps cause distortion when used as bypass caps? I used 2 of them for each op amp, but bypassed them with 10 uF electrolytic and 0.1 uF polystyrene caps. All my op amps (4) and buffer (1) can take 30V at least, so I am using slightly higher voltage, 25.6V. Now these AD4898-1 should be able to put out about 40 mA linear current into 150 ohm, and short circuit 150 mA, so I guess they can put enough to 32 ohm (+47 ohm output resistor). I had to try these until I can put them into PPAv2 which PCB should come next week. I have seen dreams about PPAv2!!_

 

Not really as hard as some make it out to be. Many cards are just built around reference design that can be found in many books or component spec sheets.


----------



## buz

Just for my understanding, the BUF634 are only used when you use the line out right? If I only use the HP out, modding them won't do anything for me?


----------



## ecclesand

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_Just for my understanding, the BUF634 are only used when you use the line out right? If I only use the HP out, modding them won't do anything for me?_

 

The BUF634s are for the HP out.


----------



## kuben

Those (AD843SQ) will fit to STX I/V circuit?


----------



## ROBSCIX

You would need two and those are rather fast so you might be looking at circuit modification or adding some components to the adapter to stabalize them.


----------



## Kuze

LT1028 sounds pretty good, still deciding which to go with LT1028 or LT1057, now to get some adapters so i can try the 49720HA's.


----------



## leeperry

Quote:


  Originally Posted by *Kuze* /img/forum/go_quote.gif 
_LT1028 sounds pretty good_

 

it sure does! especially considering that it's not used on the HP out, and that you prolly killed the chip by now...and possibly the line-out of the card too? you need adapters for single opamps: Imageshack - hd2front.jpg


----------



## Kuze

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_it sure does! especially considering that it's not used on the HP out, and that you prolly killed the chip by now...and possibly the line-out of the card too? you need adapters for single opamps: Imageshack - hd2front.jpg_

 

Just ran it for a little testing, good thing you told me, thanks.

 What about LT1057 are they single or dual?


----------



## leeperry

np, but try to be more careful in the future...some soundcards like the Claro Halo would be dead by now 
	

	
	
		
		

		
			





 here's your answer: LT1057 - Google Search


----------



## Kuze

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_np, but try to be more careful in the future...some soundcards like the Claro Halo would be dead by now 
	

	
	
		
		

		
		
	


	




 here's your answer: LT1057 - Google Search_

 

Yes i know what google is and i did check the official site, just want to confirm, thanks.
Linear Technology - LT1057 - Dual and Quad, JFET Input Precision High Speed Op Amps

 Had 637BP in there for a while and kinda want a change now, i heard some chit chatter on 49720HA's so maybe those will be next, any recommendation for the ST would be appreciated.


----------



## leeperry

http://www.linear.com/pc/productDeta...09,C1100,P1260
 "The LT1057 is a [..] dual op amp" 
	

	
	
		
		

		
		
	


	




 and OPA637 is only stable for >4 gain I think, so not quite a blind roller IMHO.


----------



## Kuze

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_Linear Technology - LT1057 - Dual and Quad, JFET Input Precision High Speed Op Amps
 "The LT1057 is a [..] dual op amp" 
	

	
	
		
		

		
		
	


	




 and OPA637 is only stable for >4 gain I think, so not quite a blind roller IMHO._

 

Rushed to take some pictures before the sun goes down, so what you recommend then?
 I have some LT1677's on hand, those any good?


----------



## leeperry

I remember trying LT1677IN8, see if it's unity gain stable? the stock LM462NA on the STX definitely is...and OPA637 isn't, you can see here that Auzen gives it incompatible w/ many of their boards: Auzentech: OPAMPS

 I also don't understand why they give AD8620 incompatible w/ some of their boards, as it's unity gain stable...and the X-Raider 7.1 feeds ±12V.

 blind opamp rolling is a risky business


----------



## Kuze

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I remember trying LT1677IN8, see if it's unity gain stable? the stock LM462NA on the STX definitely is...and OPA637 isn't, you can see here that Auzen gives it incompatible w/ many of their boards: Auzentech: OPAMPS

 I also don't understand why they give AD8620 incompatible w/ some of their boards, as it's unity gain stable...and the X-Raider 7.1 feeds ±12V.

 blind opamp rolling is a risky business 
	

	
	
		
		

		
		
	


	


_

 

Yeah i'm kinda weary about them, so I'll just stick to stock until i get good confirmation on which is best for the ST, thanks.


----------



## leeperry

the stock opamps on the STX really stink...the 2114 gives crappy trebles, and 4562 gives a dull SS/bass shy sound.

 I'm sure you can easily improve on those, using proven to work chips 
	

	
	
		
		

		
		
	


	




 like I dunno, two OPA-Earth as I/V and two AD797B as final buffer? and/or 2*LME49710HA? not sure they'd fit though as I sold my STX like 1 year ago.


----------



## Spacehead

I have terribly damaged my Sound Blaster X-FI with so many op amp changes. All solder pads are destroyed but that doesn't stop me from trying different op amps. I had a very bad crosstalk (RMAA test) -38 db but I just got it fixed and now I have -66 dB crosstalk. I soldered OPA1642 today to my card with 8 small wires. Modern op amps are so good at working in "bad" environment that they retain quality very well. I now have noise level of -93 dB , THD of 0.0021% , tested loopback with RMAA. 

 I must stay on this OPA1642 for a while now because I cannot afford to buy a new soundcard now. I had AD8620 before and I think this OPA1642 has a narrower soundstage. I have OPA1642 on my amplifier too so this is very much laidback sound. It doesn't have that airiness that AD op amps have. Mids and details are sharp, analytical. This doesn't sound bad at all , of course not. I like Hifi sound, this isn't as dry as LME49860. Not smooth, accurate instead. I am not disappointed. I chose this before AD8599 because OPA1642 works on lower voltages and has ultra low distortion.


----------



## K3cT

I have the new LME49990 in the house and I hope these can fix the massive disappointment that is the LME49710HA.


----------



## slwiser

Has anyone every put together a list of say the top 10 or 20 op amps? I know this is clearly subjective but its done all the time with other things.


----------



## buz

I am little confused by the description of the following item: 10x Dual to Mono Op amp module NE5532 TL072 to AD797BR - eBay (item 260424442924 end time Apr-03-10 05:25:52 PDT) are these in effect two AD797 on a brown dog equivalent adapter? It says it is a drop in replacement for OPA2604 but I sure cannot see the second AD797 (may be under the PCB though)


----------



## leeperry

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_I have the new LME49990 in the house and I hope these can fix the massive disappointment that is the LME49710HA._

 

hah, 49710HA major disappointment? 
	

	
	
		
		

		
			





 how do you like LT1028ACN8 btw?

 a friend of mine tried LME49990 and said that it sounded like in the virtual barbershop when he puts a plastic bag on your head


----------



## K3cT

Quote:


  Originally Posted by *slwiser* /img/forum/go_quote.gif 
_Has anyone every put together a list of say the top 10 or 20 op amps? I know this is clearly subjective but its done all the time with other things._

 

I think this is a very good idea so I'll try contributing by listing some of my personal favorites. They are AD797, LT1028, OPA627/637, AD825, AD8597, ADA4627-1 and LT1363. 

  Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_I am little confused by the description of the following item: 10x Dual to Mono Op amp module NE5532 TL072 to AD797BR - eBay (item 260424442924 end time Apr-03-10 05:25:52 PDT) are these in effect two AD797 on a brown dog equivalent adapter? It says it is a drop in replacement for OPA2604 but I sure cannot see the second AD797 (may be under the PCB though)_

 

You are most likely right. Vendors in China seem to offer those top-and-bottom configuration adapters the most often. 

  Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_hah, 49710HA major disappointment? 
	

	
	
		
		

		
		
	


	




 how do you like LT1028ACN8 btw?

 a friend of mine tried LME49990 and said that it sounded like in the virtual barbershop when he puts a plastic bag on your head 
	

	
	
		
		

		
		
	


	


_

 

Hmm... 49710 metal can version is not necessarily bad but they have a strange color to its sound. Highs are a bit rolled off too. 

 LT1028ACN8 is one of my favorites but sometimes it seems to output slightly excessive midbass which can sound bloated with my Grado HF2. I love its vocal presentation though, very sweet.


----------



## ROBSCIX

Hmm, I have build dual LME49710HA modules for many users using different gear and I have received positive feedback everytime. Maybe the circuit is just not a good match for the unit. I know there is no strange color and the highs are definately NOT rolled off atleast not on the units I have tested it with.
 However, to each their own. That is why this thread is a great idea!
 I am interested in hearing your opinion on the LME49990...


----------



## ROBSCIX

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_I have terribly damaged my Sound Blaster X-FI with so many op amp changes. All solder pads are destroyed but that doesn't stop me from trying different op amps. I had a very bad crosstalk (RMAA test) -38 db but I just got it fixed and now I have -66 dB crosstalk. I soldered OPA1642 today to my card with 8 small wires. Modern op amps are so good at working in "bad" environment that they retain quality very well. I now have noise level of -93 dB , THD of 0.0021% , tested loopback with RMAA. 

 I must stay on this OPA1642 for a while now because I cannot afford to buy a new soundcard now. I had AD8620 before and I think this OPA1642 has a narrower soundstage. I have OPA1642 on my amplifier too so this is very much laidback sound. It doesn't have that airiness that AD op amps have. Mids and details are sharp, analytical. This doesn't sound bad at all , of course not. I like Hifi sound, this isn't as dry as LME49860. Not smooth, accurate instead. I am not disappointed. I chose this before AD8599 because OPA1642 works on lower voltages and has ultra low distortion._

 

Why not go crazy with some DIY and put some sockets on there. Yes, I know the PCB has SOIC footprint but there are ways to add a DIP8 socket. This way you won't damge your card anymore and you can roll and test all you like. If you need more information let me know and I can show you some ways to go about it.

  Quote:


  Originally Posted by *slwiser* /img/forum/go_quote.gif 
_Has anyone every put together a list of say the top 10 or 20 op amps? I know this is clearly subjective but its done all the time with other things._

 

Such a list may be possible but there are just so many factors to consider. For instance 1 unit may be a favorite for one duty but not for others. I may like one when used with unit A but not with unit B. I just think a list is just too subjective to be of any use to anybody. There is just alot of factors and situations to consider.


----------



## leeperry

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_49710 metal can version is not necessarily bad but they have a strange color [..]

 LT1028ACN8 is one of my favorites but sometimes it seems to output slightly excessive midbass_

 

humm ok, like 49720...it sounds like it's oscillating, I hate that.

 LT1028ACN8 
	

	
	
		
		

		
		
	


	




 yes bass is excessively PRaT'ish, but that's what my doctor's prescription says anyway


----------



## buz

Mhh prat'ish bass. I think I'll have to get two of those combined ones from ebay


----------



## kuben

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_I am little confused by the description of the following item: 10x Dual to Mono Op amp module NE5532 TL072 to AD797BR - eBay (item 260424442924 end time Apr-03-10 05:25:52 PDT) are these in effect two AD797 on a brown dog equivalent adapter? It says it is a drop in replacement for OPA2604 but I sure cannot see the second AD797 (may be under the PCB though)_

 

"[Details at a glance] Old Stock parts, unused. include: TWO SOIC AD797BR With ONE Single Dual Op Amp to Dual Op Amp adapter." 
 Just scroll down abit 
	

	
	
		
		

		
		
	


	




 Too bad its 10pcs not 2 or 3 
 Damn i want to BUY those!


----------



## buz

kuben: I have already contacted the seller about getting 2 or 3.

 What still confuses me is one single dual op amp to dual op amp. Maybe that's just a language thing then and should read something like two single to one dual op amp 
	

	
	
		
		

		
		
	


	




 There is also Two 2x Mono to Dual OPAMP 2x LT1028 -> NE5532 OPA2604 - eBay.ch (endet 10.04.10 02:21:32 MESZ) another one with LT1028. But they are quite pricy, especially if you need two as it looks like I do...


----------



## buz

kuben: I have already contacted the seller about getting 2 or 3.

 What still confuses me is one single dual op amp to dual op amp. Maybe that's just a language thing then and should read something like two single to one dual op amp 
	

	
	
		
		

		
		
	


	




 There is also Two 2x Mono to Dual OPAMP 2x LT1028 -> NE5532 OPA2604 - eBay.ch (endet 10.04.10 02:21:32 MESZ) another one with LT1028.


----------



## leeperry

LT1028C doesn't sound nearly as good as AC IME.


----------



## kuben

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_kuben: I have already contacted the seller about getting 2 or 3.

 What still confuses me is one single dual op amp to dual op amp. Maybe that's just a language thing then and should read something like two single to one dual op amp 
	

	
	
		
		

		
		
	


	




 There is also Two 2x Mono to Dual OPAMP 2x LT1028 -> NE5532 OPA2604 - eBay.ch (endet 10.04.10 02:21:32 MESZ) another one with LT1028._

 

Great! Pm me if You get some info.
 Yes i searched those too after leeperry mentioned them


----------



## buz

So just ordered those LT1028 modules, let's see.


----------



## leeperry

simply ask the seller to relist, but he doesn't speak much english, so don't expect a reply...just refresh his ebay shop from time to time.


----------



## buz

Let's see for starters I'll try the LT1028 when I get them. I just hope my soon to arrive D2000 will be less sensitive than my RX700 so I don't have to mod the gain on my amp... In any case, I also ordered a bunch of DIP sockets and may try adding resistors to them to get the gain down


----------



## ROBSCIX

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_Let's see for starters I'll try the LT1028 when I get them. I just hope my soon to arrive D2000 will be less sensitive than my RX700 so I don't have to mod the gain on my amp... In any case, I also ordered a bunch of DIP sockets and may try adding resistors to them to get the gain down_

 

Have you tried the LT1028 before?

 The LT1028 can be unstable in some circuits, well the same as any opamp. Just be prepared to stabalize the unit if you get such issues.


----------



## Spacehead

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Why not go crazy with some DIY and put some sockets on there. Yes, I know the PCB has SOIC footprint but there are ways to add a DIP8 socket. This way you won't damge your card anymore and you can roll and test all you like. If you need more information let me know and I can show you some ways to go about it._

 

Please, I can use all the info about modding this card. I have got the THD down to 0.0022% and noise to -93 dB. Crosstalk is now -66 dB. One buddy of mine soldered LM4562 very neatly to line in so that section should be fine. I have replaced most of the caps to Panasonics. 
 But... I have now wired the op amp to the card using resistors and capacitors as contact points (for wires) as directed by bichi's picture. 
Please sign in to your eSnips account


----------



## buz

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Have you tried the LT1028 before?

 The LT1028 can be unstable in some circuits, well the same as any opamp. Just be prepared to stabalize the unit if you get such issues._

 

This would be my very first attempt at rolling opamps, well rest assured I come back here if strange things happen


----------



## ROBSCIX

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_Please, I can use all the info about modding this card. I have got the THD down to 0.0022% and noise to -93 dB. Crosstalk is now -66 dB. One buddy of mine soldered LM4562 very neatly to line in so that section should be fine. I have replaced most of the caps to Panasonics. 
 But... I have now wired the op amp to the card using resistors and capacitors as contact points (for wires) as directed by bichi's picture. 
Please sign in to your eSnips account_

 

Then I would suggest you solder up something a bit more permanent.
 Brown dog has some adapters that may help...These->Link
 You could use the above to make somethign up. However, considering how you describe your card with all the points here and there You might want to go with some DIP8 extension cables int eh picture at the bottom from AudioGD-> Link

 You could clip off the bottom socket and solder the wires to the proper points. This way you would have DIP 8 sockets to use for your opamps tests. Of course you would have to come up with a method to keep the sockets/wires under control so they weren't just hanging. Between the top and the bottom ideas you should be able to come up with something.
 Hope this helps.


----------



## ROBSCIX

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_This would be my very first attempt at rolling opamps, well rest assured I come back here if strange things happen 
	

	
	
		
		

		
		
	


	


_

 

If you get any "weirdness" let us know and we can figure out what the issue is or how to stabilize the unit.


----------



## ev666il

Hello everyone,

 I'm new to the forum and I hope this is the right place where to put my query. If it weren't, I would apologize and greatly appreciate if you could redirect me to where my query would be best put.

 I would like to upgrade the op amps in my OPPO BDP-83SE bluray player (both stereo and multichannel, for both music and movies; my experience in the past few months have led me to believe a setup that handles music in a way I like also tends to be to my liking when it comes to movies). Current onboard op amps are 5532, which I find lacking in terms of dynamics and a tad too raw in the treble.

 A friend of mine (who is much more experienced than I am in the field) replaced the op amps in his Pioneer BDP-LX91 with Opa627. I really like the way they sound but their price tag is beyond what I would like to spend for the upgrade, so he suggested I would look into the following: LM4562, Op275 and AD825. 

 I know for sure my player needs dual SMD op amps. As for my taste in terms of sound, I like it aggressive, powerful and very dynamic. I listen mostly to rock and metal and watch mainly action movies, so I need a wall of sound that physically mistreats me LOL 
	

	
	
		
		

		
		
	


	




 Besides, I like it to be clean, though I don't feel the need for an ultra-detailed sound (the 5532 are quite far from the degree of clean-ness I'd like).

 My setup is as follows:

 OPPO BDP-83SE -> VDH Thunderline RCA -> NAD M15 preamp -> VDH Thunderline RCA -> NAD M25 poweramp.

 How do you think the aforementioned op amps would behave, in my setup? And which one do you think would best match my needs and tastes?

 Thanks in advance to anyone who helps me.


----------



## ROBSCIX

First, the 5532 are duals so if you went with the OPA627 you would have to use two and an adapter and figure out a way to use them in the old 5532 footprint.

 Based on what you say you like, I think the LM4562 would be a great match.
 perhasp, you can figure out a socket idea and try out different units until you find the one you like. Look at some of the stuff in post 2422 , perhaps your buddy can solder you in some sockets!


----------



## ROBSCIX

First, the 5532 are duals so if you went with the OPA627 you would have to use two and an adapter and figure out a way to use them in the old 5532 footprint.

 Based on what you say you like, I think the LM4562 would be a great match.
 perhaps, you can figure out a socket idea and try out different units until you find the one you like. Look at some of the stuff in post 2422 , perhaps your buddy can solder you in some sockets!


----------



## ev666il

Hi Robscix,

 thanks for your answer. Unfortunately, my buddy said he wouldn't feel comfortable dealing with my player's op amps, as they're considerably smaller than the Opa627 he put in his (the BDP-LX91 carries DIP-8 op amps, whereas my Oppo carries SMD). He suggested I'd ask an artisan. I found one who would do the job if I provided him with the op amps I wanted, but basically I can't try them out before buying 
	

	
	
		
		

		
		
	


	




 I would also be unsure as to where exactly I would buy them.


----------



## 12Bass

OPA2211A might be worth trying.... a bit more open, with better low end authority as well, compared with LM4562. To my ears, LM4562 can lean toward sterile/anemic sounding.


----------



## Mad Max

Quote:


  Originally Posted by *ev666il* /img/forum/go_quote.gif 
_Hi Robscix,

 thanks for your answer. Unfortunately, my buddy said he wouldn't feel comfortable dealing with my player's op amps, as they're considerably smaller than the Opa627 he put in his (the BDP-LX91 carries DIP-8 op amps, whereas my Oppo carries SMD). He suggested I'd ask an artisan. I found one who would do the job if I provided him with the op amps I wanted, but basically I can't try them out before buying 
	

	
	
		
		

		
		
	


	




 I would also be unsure as to where exactly I would buy them._

 

edit: Italy? Maybe Farnell or Digikey then.


----------



## leeperry

Quote:


  Originally Posted by *ev666il* /img/forum/go_quote.gif 
_basically I can't try them out before buying_

 

that's also an option: DIP8 to SO8 Adapter

 you could also use discrete opamps like OPA-Earth...or use one more adapter on top of this one and use two OPA627BP/LT1028ACN8, or just this: Dual to Mono Op amp module AD797BR - eBay

 better save some money for your opamp upgrade...because LM4562/OP275 sounds really bad, a shootout against your friend's unit will sadden you for sure.

 Burson also has instructions on how to hack SOIC8 chips(better use the shortest shielded wires you can): Burson HD Opamp 101 Part 2 (Soft Extension Cable for SMD)

 you can use the same technique w/ a DIP8 socket or this: Single-to-dual Op-AMP Adapter - DIP version
 et voilà


----------



## ev666il

*Mad Max: *thank you very much for the links!!

*leeperry:* thank you a lot for your reply. Is making use of those adapters really neutral towards sound? 

 I'm quite surprised to hear the Op275 sounds bad: I've heard it on my friend's Meridian G98 (he only uses it for regular CDs now but had me listen to a few DVDs on it, too) and thought it sounded quite good. Of course we're talking two entirely different players, so a direct comparison with his modified BDP-LX91 would at best be unfair. But I can say for sure his vanilla Meridian sounds better than my vanilla Oppo.

 I understand and accept I can't have Opa627-quality without actually resorting to Opa627, but they really are pricy. Let's say I'm looking for the second best 
	

	
	
		
		

		
			





 Something that would be a significant improvement over my current 5532, without necessarily being as good as Opa627.

 What about AD825? Are they any good?


----------



## leeperry

prego 
	

	
	
		
		

		
		
	


	




 well, you should keep the wires as short as possible, and use shielded ones....also don't use very fast opamps, as they'd be prone to oscillate very easily.

 anyway, you could also add decoupling caps to improve stability...like a 0.1uf red WIMA cap between pins 4 and 8, but I'm sure the guy who'd do it for you would know what's good to improve the opamp rolling.

 OPA627 is said to be as good or worse than the AD797BR I linked on ebay, it's one of the major contenders for prime SQ...and its price is very reasonable too 
	

	
	
		
		

		
		
	


	




 ask your friend how much is fed to the opamps too, because depending on whether it's ±5V or ±12V it'll be a different story. I think putting AD797BR in yours will motivate your friend w/ the OPA627 mod to do the same 
	

	
	
		
		

		
		
	


	




 It's widely agreed in this thread that single opamps sound far better than duals, as it's often recommended to go dual mono over stereo in the audio world.

 majkel said that OP275 was "mediocre", and it was also sounding pretty ugly in the Musiland 02US.


----------



## buz

Is the AD797BR adapter still worth it over the LT1028 if I need two of them?


----------



## leeperry

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_Is the AD797BR adapter still worth it over the LT1028 if I need two of them?_

 

you bought LT1028CS8 anyway? LT1028ACN8 sounded noticeably better IME, AC being a higher grade than C.

 well, I tried to share my honest views about 797/1028 here: http://www.head-fi.org/forums/6522358-post167.html

 and you can search majkel's posts for "LT1028ACN8", he found the same differences between these 2 chips.


----------



## buz

This is lt1028csw not cs8. Anyway, 20USD for two duals was decent'ish.


----------



## ROBSCIX

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_Is the AD797BR adapter still worth it over the LT1028 if I need two of them?_

 

Almost every opamp we mention has it's own flavor and could possibly be a great match for your gear.


----------



## leeperry

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_This is lt1028csw not cs8._

 

it's an error in their listing, it's more than likely CS8.

 here's some posts from majkel about 797/1028:
http://www.head-fi.org/forums/6169591-post1713.html
http://www.head-fi.org/forums/5257829-post26.html
http://www.head-fi.org/forums/5355562-post30.html
http://www.head-fi.org/forums/5865241-post238.html
http://www.head-fi.org/forums/5848673-post122.html
  Quote:


 The LT1028ACN8 make it happen, the AD797BRZ and the LME49860 do it in a lesser degree. Others don't do it at all. 
 

I'd agree...the 797B SS is more impressive than 1028AC, but 1028AC just "_makes it happen_"(please note that these were his thoughts at that time, he's prolly changed his mind by then).

 I'll try ADA4627-1B soon or later


----------



## buz

The LT1028AC would have to be damn good to warrant buying two (possibly four) of them at 30USD a pop just to stick it into a 120USD amp...


----------



## leeperry

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_The LT1028AC would have to be damn good to warrant buying two (possibly four) of them at 30USD a pop_

 

lucky us it's so cheap, I think they should have priced it like OPA627SM to be taken more seriously.


----------



## buz

Is there any reliable ebay source for them? I can only find them at farnell and their price is thru the roof...

 Still unconvinced if I want to pay as much for the opamps as I did for the whole DAC/amp...


----------



## ROBSCIX

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_The LT1028AC would have to be damn good to warrant buying two (possibly four) of them at 30USD a pop just to stick it into a 120USD amp..._

 

They are not bad but certainly not the be all to end all of opamps.
 There are others that are just as pricey or more so.
 You can find many units that have hefty price tags however, if you are going to go with such a unit you might want to make sure you have a good circuit and playback gear to hear everything that is available.


----------



## leeperry

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_Still unconvinced if I want to pay as much for the opamps as I did for the whole DAC/amp_

 

a friend of mine bought an HA-INFO HA27 on my advice...it came w/ an OP275, that sounded worthless in his opinion compared to 2*LT1363CN8/2*AD797BR(which he's currently using fed to the 2*BUF634 to his ATH-AD900)...he's ordered 2*LT1028ACN8 now, I've poisoned him for good 
	

	
	
		
		

		
		
	


	




 opamps color the sound far more than DAC chips ever will IMO...I've even put a Burson on a cheapo CMI8768 PCI board, what's wrong w/ that? it sounds amazing: http://www.head-fi.org/forums/6491943-post10.html


----------



## Spacehead

have any of you tried ADA4898-1 

 it has pretty high input bias currents so it generates offset voltage, but it can be made to work by changing gain resistors and + input side to equal 

 It is my current favorite op amp. 

 How much my source masks the sound of different op amps that I use on DIY amplifiers?

 Is OPA1642 transparent or not?


----------



## majkel

Best bang for the buck is to place the LME49860NA instead of the NE5532. Lowest DIY effort, better than a pair of the AD825 which are nice, BTW.


----------



## ev666il

What about AD8066?


----------



## 12Bass

Still suggest OPA2211A. LM4562/LME49710/LME49860 are all very similar, somewhat sterile, and a tad lean in the lows. OPA2211A is somewhat more vibrant and full sounding. AD825 has an interesting coloration, perhaps a bit of a loudness contour type sound. I grew tired of it, except in certain applications where such coloration was desirable. OPA275 is somewhat peculiar sounding, and not very low distortion.


----------



## Mad Max

I've hit the jackpot again.

 I love AD744JNZ's midrange tonality in my gear, and AD744AH (the metal can version) is a nice big jump over it with the same midrange. Another fantastic opamp. Pretty close to ADA4627-1BRZ in refinement.


----------



## Mad Max

*double post*


----------



## leeperry

I've received another AD797BR module from that chinese ebay seller, it's perfectly soldered this time!

 and a friend of mine has put one to good use in his Audio-GD FUN:


----------



## buz

That was audjade_chn, right? Any impressions?


----------



## majkel

I'd raher stay with the NE5532 if it only were TI or Signetics.


----------



## leeperry

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I'd raher stay with the NE5532 if it only were TI or Signetics._

 

fully agreed(I have yet to hear a TI chip I'd like), but where did the OPA228P love go then? 
	

	
	
		
		

		
			




  Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_That was audjade_chn, right?_

 

yup


----------



## ecclesand

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_I've hit the jackpot again.

 I love AD744JNZ's midrange tonality in my gear, and AD744AH (the metal can version) is a nice big jump over it with the same midrange. Another fantastic opamp. Pretty close to ADA4627-1BRZ in refinement._

 

I have a set of the AD744KN in my Parasound DAC. I did the output bypass mod and they sound fantastic. Did you do the same with yours or stock? I should give the metal can versions a try with the output bypass.


----------



## 12Bass

Hmmm.... have a pair of OPA228 DIPs around that need to be mounted in an adapter. I'm surprised that people think that NE5532 is better than OPA2211A. Can't hear that at all. I've tried the OPA211/2211A series in a variety of applications, and they always sound good to me. Something like 2xAD797 might be superior in some ways, but is not easy to implement. I suggested the dual because mounting two single SOICs is a pain..... though something I did recently in the preamp of my Behringer Mixer.... put one SOIC single on top the the other. Very intricate soldering!


----------



## leeperry

having second thoughts, I prefer 4580 over 5532...there's something intriguing to this chip...bang for bucks is huge, higher than 5532 IMO.


----------



## 12Bass

JRC4580? Hmmm... not me... find it sort of veiled, yet edgy, at the same time. Not a hi-fi chip at all, IMO. One of the first to go if I find it on a PCB....


----------



## leeperry

well, there's no one-size-fits-all anyway, but for driving headphones I like it...but yes, as AK4396 LPF, it was quite unbearable after a little while. anyway, we're talking as if LT and AD didn't exist


----------



## 12Bass

Have you tried AD8397 for driving headphones? Should be better than JRC/NJM4580.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Hmmm.... have a pair of OPA228 DIPs around that need to be mounted in an adapter. I'm surprised that people think that NE5532 is better than OPA2211A. Can't hear that at all. I've tried the OPA211/2211A series in a variety of applications, and they always sound good to me. Something like 2xAD797 might be superior in some ways, but is not easy to implement. I suggested the dual because mounting two single SOICs is a pain..... though something I did recently in the preamp of my Behringer Mixer.... put one SOIC single on top the the other. Very intricate soldering! 
	

	
	
		
		

		
		
	


	


_

 

Post your impressions on these I would be interested in hearing your opinions of these units.


----------



## Mad Max

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I have a set of the AD744KN in my Parasound DAC. I did the output bypass mod and they sound fantastic. Did you do the same with yours or stock? I should give the metal can versions a try with the output bypass._

 

Stock. I have AD744KN as well, and it is not much of an improvement over the J version. I haven't modded any of the opamps, and I'm pretty sure you'll love the metal can version. It synergizes better with my ipod than my Compass DAC, making my portable rig more natural sounding. It is a very tight fit in my amp, so no mods yet. I'll try the OB mod later, though.

 I can't decide whether I like 4627-1B or 744AH better.


----------



## ecclesand

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_Stock. I have AD744KN as well, and it is not much of an improvement over the J version. I haven't modded any of the opamps, and I'm pretty sure you'll love the metal can version. It synergizes better with my ipod than my Compass DAC, making my portable rig more natural sounding. It is a very tight fit in my amp, so no mods yet. I'll try the OB mod later, though.

 I can't decide whether I like 4627-1B or 744AH better. 
	

	
	
		
		

		
			



_

 

I too like the ADA4627...it's in my top 5 for sure. I ordered a set of the 744AH from the Ebay link so thank you for that! I think I'll try them stock first for a week or so before doing the bypass mod.


----------



## ihrm

Hey all, noob here. I'm not at all sure what an opamp. Could anyone try to explain or link me to some good reading?


----------



## ROBSCIX

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I too like the ADA4627...it's in my top 5 for sure. I ordered a set of the 744AH from the Ebay link so thank you for that! I think I'll try them stock first for a week or so before doing the bypass mod.
	

	
	
		
		

		
		
	


	


_

 

Wow, just reminded me. I have a few of these that need to be put on some adapters for testing. So many units and so little time!


----------



## theSeekerr

Quote:


  Originally Posted by *ihrm* /img/forum/go_quote.gif 
_Hey all, noob here. I'm not at all sure what an opamp. Could anyone try to explain or link me to some good reading?_

 

An opamp (Operational Amplifier) is a particular kind of differential amplifier (that is, it has two intputs, and amplifies the difference between them). It has very high input impedance, very low output impedance, and extremely high gain.

 Since all opamps have these properties, they can be treated as a fundamental electronics building block. (Historically, this isn't quite true, but it's been basically true since the u741, invented in 1968).

 Some notes on their operation and history can be found at : Operational amplifier - Wikipedia, the free encyclopedia

 While some notes on their usefulness can be found at:
Operational amplifier applications - Wikipedia, the free encyclopedia

 Along with their uses as small-signal amplifiers, they can also be used as elements in analogue computing (adders, integrators, differentiators), control circuits (zero level detectors, Schmitt triggers), and to do some rather nifty things (inductance simulators, negative resistance simulators)

 Here, though, we mostly use them as gain stages in headphone amplifiers and buffer stages in Digital to Analogue converters. Much of the discussion centres around which opamps sound the best, although realistically, there are now many modern opamps with distortion levels so low they should be indistinguishable from each other.


----------



## foureight84

I've been looking for the OPA627SM for my soundcard, and I found this on eBay 2 pcs of BB OPamp IC OPA627SM (OPA627) + DIP adapter - eBay (item 120354248036 end time Apr-18-10 06:58:46 PDT)

 It seems too good to be true. The price is really cheap for the 627sm and it comes with the DIP adaptor which looks exactly like what auzentech sells on their website. Has anyone ever bought from this seller? I want this for my headphones and front channel (running on the auzentech bravura).


----------



## foureight84

Quote:


  Originally Posted by *foureight84* /img/forum/go_quote.gif 
_I've been looking for the OPA627SM for my soundcard, and I found this on eBay 2 pcs of BB OPamp IC OPA627SM (OPA627) + DIP adapter - eBay (item 120354248036 end time Apr-18-10 06:58:46 PDT)

 It seems too good to be true. The price is really cheap for the 627sm and it comes with the DIP adaptor which looks exactly like what auzentech sells on their website. Has anyone ever bought from this seller? I want this for my headphones and front channel (running on the auzentech bravura)._

 

Meh probably not a good idea since I just saw that the seller is based in Hong Kong. If it's too good to be true it probably is right? heh


----------



## ihrm

Quote:


  Originally Posted by *theSeekerr* /img/forum/go_quote.gif 
_An opamp (Operational Amplifier) is a particular kind of differential amplifier (that is, it has two intputs, and amplifies the difference between them). It has very high input impedance, very low output impedance, and extremely high gain.

 Since all opamps have these properties, they can be treated as a fundamental electronics building block. (Historically, this isn't quite true, but it's been basically true since the u741, invented in 1968).

 Some notes on their operation and history can be found at : Operational amplifier - Wikipedia, the free encyclopedia

 While some notes on their usefulness can be found at:
Operational amplifier applications - Wikipedia, the free encyclopedia

 Along with their uses as small-signal amplifiers, they can also be used as elements in analogue computing (adders, integrators, differentiators), control circuits (zero level detectors, Schmitt triggers), and to do some rather nifty things (inductance simulators, negative resistance simulators)

 Here, though, we mostly use them as gain stages in headphone amplifiers and buffer stages in Digital to Analogue converters. Much of the discussion centres around which opamps sound the best, although realistically, there are now many modern opamps with distortion levels so low they should be indistinguishable from each other._

 

Ok thanks! That clears things up. I was looking at the wikipedia article earlier, but it didnt really give me a good idea of what we would use them for. I'm looking at buying a Zero DAC off eBay and there are 2 opamp options. OPA627 or the OPA2604. Whats the difference between them? Is it worth spending the extra money on the OPA627? Thanks again


----------



## leeperry

Quote:


  Originally Posted by *foureight84* /img/forum/go_quote.gif 
_Meh probably not a good idea since I just saw that the seller is based in Hong Kong. If it's too good to be true it probably is right? heh_

 

this is a very serious seller AFAIK, ask him if they're genuine and if you can see the TI box they come in 
	

	
	
		
		

		
		
	


	




 for this price you can get a whole bunch of OPA-Earth, or a Burson V2...so they'd have to be genuine, and sound really good!

 Andrea is poisoning me to try AD845KN...must resist


----------



## ROBSCIX

Quote:


  Originally Posted by *foureight84* /img/forum/go_quote.gif 
_Meh probably not a good idea since I just saw that the seller is based in Hong Kong. If it's too good to be true it probably is right? heh_

 

You have to watch some ebay sellers as they sell counterfeit components.
 I have no experience with the sellers you posted but just saying be carful.


----------



## foureight84

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_You have to watch some ebay sellers as they sell counterfeit components.
 I have no experience with the sellers you posted but just saying be carful._

 

Yea it's a good idea. I thought it's kinda cheap since the OPA627SM goes for $70 each... This is $50 for two, so it does sound really too good. I noticed that he has sold a bunch and with 100% + feedback, he seems legit. I emailed the seller for more information as you guys suggested. Going to confirm with TI after.


----------



## foureight84

How does the sound quality differ between the opa627sm vs opa627ap?


----------



## foureight84

I finally settled and bought a pair of OPA627AU. 
	

	
	
		
		

		
		
	


	




 I can't wait to try them out. 

 I have a question though, I have a Auzentech Bravura sound card and it's setup with a pair of Audioengine A2 with a Polkaudio PSW111 sub connected through the speakers. Will I get better bass if I were to connect the sub to my soundcard via a y-adapter and replace the sub channel's opamp with one known for deeper bass?


----------



## buz

So I got my LT1028 today - how do I easily measure DC offset before frying heapdhones (only have a cheap DMM at hand right now)? Could I use a mini to mini on the HP out and the DMM with that?


----------



## Mad Max

Quote:


  Originally Posted by *foureight84* /img/forum/go_quote.gif 
_I finally settled and bought a pair of OPA627AU. 
	

	
	
		
		

		
		
	


	




 I can't wait to try them out. 

 I have a question though, I have a Auzentech Bravura sound card and it's setup with a pair of Audioengine A2 with a Polkaudio PSW111 sub connected through the speakers. Will I get better bass if I were to connect the sub to my soundcard via a y-adapter and replace the sub channel's opamp with one known for deeper bass?_

 

Most likely.


  Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_So I got my LT1028 today - how do I easily measure DC offset before frying heapdhones (only have a cheap DMM at hand right now)? Could I use a mini to mini on the HP out and the DMM with that?_

 

I think so.


----------



## leeperry

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_So I got my LT1028 today - how do I easily measure DC offset before frying heapdhones (only have a cheap DMM at hand right now)? Could I use a mini to mini on the HP out and the DMM with that?_

 

that's how I do it! but I've never got any DC on the 1028...OTOH on 1363/797B


----------



## ROBSCIX

Quote:


  Originally Posted by *foureight84* /img/forum/go_quote.gif 
_Yea it's a good idea. I thought it's kinda cheap since the OPA627SM goes for $70 each... This is $50 for two, so it does sound really too good. I noticed that he has sold a bunch and with 100% + feedback, he seems legit. I emailed the seller for more information as you guys suggested. Going to confirm with TI after._

 

It is better to be safe the sorry. I have heard both the OPA627 and 637SM and they are quite nice. As to if they are worth the asking price, that is up to you. I see by the other post you went with a different model over the TO-99 SM modules.


----------



## buz

Too late to go mess around with opamps tonight but I think I'll give this shot on Saturday...

 I'm wondering, it is says
 LT812
 1028
 (two lines) on the SMD chips - is that normal or are these clearly fake? If so, any place where I could get legit LT1028A, preferably already on dual adapters or possibly as DIPs?


----------



## leeperry

not fake


----------



## buz

So mine look very similar, except that it says 812 on them... Have not yet ordered any AD797. Ah well, will give the LT1028 a try on Saturday for sure.


----------



## leeperry

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_it says 812_

 

batch/plant number of some sort


----------



## buz

Ah well, if I don't feel it sounds good, I will go hunt for a real LT1028A 
	

	
	
		
		

		
			





. And maybe that M-Stage while I am at it


----------



## Spacehead

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Then I would suggest you solder up something a bit more permanent.
 Brown dog has some adapters that may help...These->Link
 You could use the above to make somethign up. However, considering how you describe your card with all the points here and there You might want to go with some DIP8 extension cables int eh picture at the bottom from AudioGD-> Link

 You could clip off the bottom socket and solder the wires to the proper points. This way you would have DIP 8 sockets to use for your opamps tests. Of course you would have to come up with a method to keep the sockets/wires under control so they weren't just hanging. Between the top and the bottom ideas you should be able to come up with something.
 Hope this helps._

 

I am trying very hard 





 that is a differential-to-single-ended converter 

 my SNR is very poor now, there is pretty loud hiss in the background. OPA1642 has good voltage swing there and output is quite distortion free.

 I have not yet fully understood what I should do.

 The CS4382 datasheet recommends Sallen-Key 2-pole filter to the dac outputs. It is implemented on the card but I am trying to learn things so I built my own.

 I have gain of -6 there, so first I could try to reduce it. My PPA v2 has a lot of quiet gain available.

 ps. bought another X-FI for better RMAA results (testing purposes).


----------



## Spacehead

There was still one good circuit on the X-FI PCB. I routed front channel to it from DAC and changed AD8066 to there. Nice clean solder joints and only 6 wires needed.

 It didn't make the sound too bad:
http://i42.tinypic.com/25yx72h.jpg

 SNR: 95 dB 
 THD: 0.0024% 

 I think that is hifi enough. 

 I have learned to solder soic8 op amps quite skillfully, it is very easy to change them now without breaking the pads.


----------



## Mad Max

Hmm, I thought through-hole soldering would be easier than SMD soldering, but i am finding the reverse to be the truth.


----------



## Spacehead

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_Hmm, I thought through-hole soldering would be easier than SMD soldering, but i am finding the reverse to be the truth._

 

And circuits done in SMD sound better due to lower noise.


----------



## 12Bass

Depends... SOIC takes good eyesight and fine motor skills. Also, the lack of sockets is problematic for swapping chips.


----------



## kuben

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_not fake 

_

 

I can use those 797's in STX I/V?


----------



## leeperry

Quote:


  Originally Posted by *kuben* /img/forum/go_quote.gif 
_I can use those 797's in STX I/V?_

 

they will fit, and will also most likely work...they work perfectly fine in my PCM1793 DAC, and AD797 is said to be a drop-in replacement for LM4562 
	

	
	
		
		

		
		
	


	




 the ebay seller is using better looking adapters now: http://i.ebayimg.com/22/!BqHZITw!Wk~...LwyoQ~~_12.JPG


----------



## murrays

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_they will fit, and will also most likely work...they work perfectly fine in my PCM1793 DAC, and AD797 is said to be a drop-in replacement for LM4562 
	

	
	
		
		

		
		
	


	


_

 

Not really a "drop in": the AD797 is a single and the LM4562 is a dual.


----------



## leeperry

indeed, I meant using adapters of course


----------



## ROBSCIX

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_Not really a "drop in": the AD797 is a single and the LM4562 is a dual._

 

You beat me to it.


----------



## ev666il

Has anyone tried the AD712? How does it sound?


----------



## buz

So I am looking at the DIP adapters of my LT1028, where would I need to add what resistors to significantly lower gain of my NG98? It's simply too loud with all of my cans...


----------



## Mad Max

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_So I am looking at the DIP adapters of my LT1028, where would I need to add what resistors to significantly lower gain of my NG98? It's simply too loud with all of my cans..._

 

That's what I'd like to know as well.


----------



## Spacehead

I got a new Sound Blaster X-FI , model number SB0670. It works with same drivers than SB0460 so no problems here even it is OEM card. 
 Modding was the same than with previous card, but this time I was very careful as I wanted to keep the high performance of this card intact but change the op amp to one that gives me most pleasure, AD8599. It isn't as transparent as AD8066/AD8620/AD8022 but it is the least fatiguing.

 Here are some pics of the change: 





http://i44.tinypic.com/346qp0g.jpg

http://i40.tinypic.com/263ahzs.jpg

http://i40.tinypic.com/oum639.jpg

 And testing results:
http://i40.tinypic.com/k1evci.jpg
 100 dB SNR 
 0.0017% THD
 those are pure hifi to me! 
 It seems that AD8599 produces a little different harmonics than NJM4556. 

 Performance suffered a little, maybe from cold joints in bypassing the decoupling caps. There is no other mods yet. 

 If you say change AD8599 to something else, I might just do it, but not without good reasoning, the solder pads don't like desoldering! I think I need to get AD4898-2 !! that would be extremely transparent.

 ps. Would I benefit from a high quality shielded cable 
 3.5 mm-> 2 RCA ? From x-fi to PPA V2


----------



## netsky3

Can someone help me to choose a good opamp for my amp?
 I have a kit by oatley like these Raytheon JAN6418 Valve (Tube) Preamplifier / Headphone Amp Kit but i'd like to do some tweaks.
 Now the output power is just enough for a good volume, there are opamps wich can drive better my AKG at 55ohms? 
	

	
	
		
		

		
		
	


	



 Sorry for the dumb question...


----------



## kuben

AD797BR AD797 SOIC to DIP Adaptor with IC NEW! (1 PC) - eBay (item 370363043171 end time May-09-10 23:29:26 PDT)
AD797AR AD797 SOIC to DIP Adaptor with IC NEW! (1 PC) - eBay (item 370363043615 end time May-09-10 23:32:07 PDT)

Dual AD797AR AD797 SOIC to DIP Adaptor with IC New! 1PC - eBay (item 370363041983 end time May-09-10 23:23:37 PDT)
 Yeah at last dual ad797 on 8dip adaptor!
 (ordering)


----------



## kuben

AD797BR AD797 SOIC to DIP Adaptor with IC NEW! (1 PC) - eBay (item 370363043171 end time May-09-10 23:29:26 PDT)
AD797AR AD797 SOIC to DIP Adaptor with IC NEW! (1 PC) - eBay (item 370363043615 end time May-09-10 23:32:07 PDT)

Dual AD797AR AD797 SOIC to DIP Adaptor with IC New! 1PC - eBay (item 370363041983 end time May-09-10 23:23:37 PDT)
 Yeah at last dual ad797 on 8dip adaptor!
 (ordering)


----------



## buz

My understanding is you really want AD797BR, not AR

 So more like http://cgi.ebay.com/ws/eBayISAPI.dll...m=350336041861


----------



## qusp

hehe, the performance between the AR and BR is negligible at best IMO, even the spec sheet is pretty much identical, plus I wouldnt trust buying BR on ebay anyway


----------



## ROBSCIX

Quote:


  Originally Posted by *qusp* /img/forum/go_quote.gif 
_hehe, the performance between the AR and BR is negligible at best IMO, even the spec sheet is pretty much identical, plus I wouldnt trust buying BR on ebay anyway_

 

Yes, some same they hear a difference and some say they do not.

 @Spacehead, if you did the soldering, it looks pretty good. I like asking other people about their SOIC soldering techniques. Can you give me a run down of how you go about it?


----------



## Spacehead

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_@Spacehead, if you did the soldering, it looks pretty good. I like asking other people about their SOIC soldering techniques. Can you give me a run down of how you go about it?_

 

Yes that is my work. 

*To remove the op amp:*
 I add solder to both sides so that legs get together. Then I alternate between sides heating with iron, I keep fast pace. At the same time I push it from the other side, when solder on both sides is hot enough the soic op amp slides away from the solder pads. When I notice it starts to move I lift it a bit too so that it clears any parts on the pcb. 
 Then I have a lot of solder on soic pads on PCB. I use solder wick to suck all the excess solder, I make the pads dry from solder. Then I use ethanol to clean the flux and dirt. Then pads are shiny and there is no impurities. 
*To add a new op amp:*
 I put some solder on new op amps legs. I might add some solder to soic pads on PCB but it is more difficult to get right amount there so I leave them dry usually. 
 There should be enough solder now on the op amps legs. 
 I put it down on soic pads, make sure it is properly aligned, I keep it still with tweezers. I touch legs and pad with iron, then the solder on op amp legs melts and forms a good joint between pad and leg. I need to press the op amp down sometimes a bit so that there won't be large gaps that would need to be filled.
 Now it is very easy to solder rest of the legs and pads together. I check with multimeter that there is connection (0 resistance). If there is poor connection I add some solder directly to legs and pads, usually only 0.5 second apply is enough.


 This all requires excellent eye sight and good steady hands, I am excited that I can do this. But there is always risk of failure. I have too large soldering iron tip for re-soldering very small SMD parts , 1.2 mm. 

 BTW. AD8599 hisses on my X-FI. I think I need to change it. Would the AD8620 be stable and good sounding? On X-FI op amps purpose is to convert differential to single ended and filtering.


----------



## 12Bass

What was the original op amp on the X-Fi? Have you thoroughly cleaned the area around the SOIC? Might be a bad solder joint. AD8599 hasn't been a problem for me... other than I find it a bit too warm sounding.


----------



## Spacehead

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_What was the original op amp on the X-Fi? Have you thoroughly cleaned the area around the SOIC? Might be a bad solder joint. AD8599 hasn't been a problem for me... other than I find it a bit too warm sounding._

 

All my AD8599 seem to hiss a little. Original op amp was NJM4556. I have cleaned it very well IMO, but maybe the denatured ethanol leaves some residue which is conductive. 
 Joints should be good.

 Now I already changed the op amp to AD8620 but it had that hissing too, I wonder what is going on. I hope to get that fixed without failing the card.


----------



## lordearl

Can anyone recommend a replacement for OPA2134 (hence, dual - browndogs won't fit my unit) that has excellent PSRR? My PSU is a wall wart (says regulated, but I doubt it), so trying to hunt down an opamp with the best PSRR.

 Additionally, the headphone amp this is for uses a circuit which biases the output heavily into class A - any chips out there which would benefit from this?


----------



## buz

You can get dual SMDs that are marginally larger than a normal dip package on ebay for quite a few opamps.

 BTW: is it safe to plugin the 200USD headphones if the Sansa throwaways work fine? My DMM seems to be out of power


----------



## lordearl

thanks buz,
 can you put a link up so I can see what I'm looking for?

 cheers mate


----------



## lordearl

thanks buz,
 can you put a link up so I can see what I'm looking for?

 cheers mate


----------



## buz

Dual to Mono Op amp module 4558 NE5532 TL072 to AD797BR - eBay (item 350336041861 end time May-02-10 05:48:20 PDT)

 Tho watch out, many fakes on ebay. That particular seller is probably ok but you never really know


----------



## lordearl

wow that's tiny, excellent - not ultra cheap, but still, the soldering is done so that makes it easy. I'll try to find one with exceptional PSRR, let me know if you think of one.


----------



## netsky3

Quote:


  Originally Posted by *netsky3* /img/forum/go_quote.gif 
_Can someone help me to choose a good opamp for my amp?
 I have a kit by oatley like these Raytheon JAN6418 Valve (Tube) Preamplifier / Headphone Amp Kit but i'd like to do some tweaks.
 Now the output power is just enough for a good volume, there are opamps wich can drive better my AKG at 55ohms? 
	

	
	
		
		

		
		
	


	



 Sorry for the dumb question..._

 

 Quote:


  Originally Posted by *kuben* /img/forum/go_quote.gif 
_AD797BR AD797 SOIC to DIP Adaptor with IC NEW! (1 PC) - eBay (item 370363043171 end time May-09-10 23:29:26 PDT)
AD797AR AD797 SOIC to DIP Adaptor with IC NEW! (1 PC) - eBay (item 370363043615 end time May-09-10 23:32:07 PDT)

Dual AD797AR AD797 SOIC to DIP Adaptor with IC New! 1PC - eBay (item 370363041983 end time May-09-10 23:23:37 PDT)
 Yeah at last dual ad797 on 8dip adaptor!
 (ordering)_

 

Your reply is for me?


----------



## kuben

Quote:


  Originally Posted by *netsky3* /img/forum/go_quote.gif 
_Your reply is for me? 
	

	
	
		
		

		
		
	


	


_

 

No, but i maybe it can 
	

	
	
		
		

		
		
	


	




 AD797BR's are dual or single?
 For stx i need dip8 dual opamps.


----------



## buz

AD797 is single, but the link above is for two AD797 on single to dual adapter (disclaimer: I did not try it)


----------



## ROBSCIX

Quote:


  Originally Posted by *kuben* /img/forum/go_quote.gif 
_No, but i maybe it can 
	

	
	
		
		

		
		
	


	




 AD797BR's are dual or single?
 For stx i need dip8 dual opamps._

 


 The ST(X) requires dual channel opamps in all three replacable sockets.

 You would need to buy or make adapter units with two AD797 units on each adapter.


----------



## netsky3

Quote:


  Originally Posted by *kuben* /img/forum/go_quote.gif 
_No, but i maybe it can 
	

	
	
		
		

		
		
	


	




 AD797BR's are dual or single?
 For stx i need dip8 dual opamps._

 

LOL!
 I'm looking for a good opamp on ebay at low price but i don't know own qualities and i'm interested to a good power that can drive my headphones.
 No one can help me?


----------



## lordearl

netsky - I built that kit - you don't need to change the opamp. Let the amp burn in for at least 100 hours, then consider it. The opamp won't really change the sound.....


----------



## netsky3

Quote:


  Originally Posted by *lordearl* /img/forum/go_quote.gif 
_netsky - I built that kit - you don't need to change the opamp. *Let the amp burn in for at least 100 hours, then consider it. The opamp won't really change the sound.....*_

 

Really?
 In another topic a user has tried some opamps and said the vary differences to the sound.
 Another thing important for me is the output power, i'd like to increase if possible, do you think that the supply of 12V is not enough for my akg? 
	

	
	
		
		

		
		
	


	



 Thanks


----------



## lordearl

I think it's always important to hear the sound signature before you make a change - otherwise you won't know what to listen out for.

 I have the K701 and the power is fine....


----------



## Mad Max

AD8065AR pumps out more juice than the other opamps I have, barring 797.
 It is a mono opamp, so it needs to be soldered to a 2x1 adapter or something.

 For dip8 mono opamps, I bought a pair of these and they are excellent. Very sturdy and very good contact. I bought these to replace the ones I bought months ago from vze3k8zw, they are terrible, oxidized already, and make very poor contact without bending the pins quite a bit.


----------



## netsky3

Quote:


  Originally Posted by *lordearl* /img/forum/go_quote.gif 
_I think it's always important to hear the sound signature before you make a change - otherwise you won't know what to listen out for.

 I have the K701 and the power is fine...._

 

Sure but for few dollars i'd like to try something 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_AD8065AR pumps out more juice than the other opamps I have, barring 797.
 It is a mono opamp, so it needs to be soldered to a 2x1 adapter or something.

 For dip8 mono opamps, I bought a pair of these and they are excellent. Very sturdy and very good contact. I bought these to replace the ones I bought months ago from vze3k8zw, they are terrible, oxidized already, and make very poor contact without bending the pins quite a bit._

 

Interesting


----------



## Spacehead

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_All my AD8599 seem to hiss a little. Original op amp was NJM4556. I have cleaned it very well IMO, but maybe the denatured ethanol leaves some residue which is conductive. 
 Joints should be good.

 Now I already changed the op amp to AD8620 but it had that hissing too, I wonder what is going on. I hope to get that fixed without failing the card._

 

I have not been able to fix that. That is maybe a failed card ... Can't believe it, just bought it!!!


----------



## Spacehead

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Then I would suggest you solder up something a bit more permanent.

 You could clip off the bottom socket and solder the wires to the proper points. This way you would have DIP 8 sockets to use for your opamps tests. Of course you would have to come up with a method to keep the sockets/wires under control so they weren't just hanging. Between the top and the bottom ideas you should be able to come up with something.
 Hope this helps._

 

I did my own adapter:
















 test results
http://i40.tinypic.com/121aeth.jpg
 (Tested with Creative's testing methodology)


 Card is terrible looking but works. But of course only for front channel.


----------



## Spacehead

those tantalums sounded very harsh and hard. I had to remove them. I didn't have anything super good at hand so I used these mylar 0.1 uF capacitors. They sound softer and listenable now with AD8620. My ears are feeling odd now, maybe I am trying to find out imperfections or something.


----------



## 12Bass

Interesting DIP -> SOIC adapter! BTW, something like a toothbrush can be used to remove remaining contaminants from the PCB.


----------



## 12Bass

Interesting DIP -> SOIC adapter! BTW, something like a toothbrush can be used to remove remaining contaminants from the PCB.

 Can see the low end roll-off on the LME49860 in the RMMA graphs.

 Edit: this forum sucks for posting. Takes forever to respond. BLAH!


----------



## Spacehead

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Interesting DIP -> SOIC adapter! BTW, something like a toothbrush can be used to remove remaining contaminants from the PCB.

 Can see the low end roll-off on the LME49860 in the RMMA graphs.

 Edit: this forum sucks for posting. Takes forever to respond. BLAH!_

 

Yeah AD8066 gives best bass response. 
 I have used toothbrush too but I think that stuff is residue from the denatured ethanol... or does the toothbrush plastic dissolve in ethanol ?!

 And about the dip to soic mod, this is huge for me! The changes in the source sound so clearly that I am pretty amazed.

 And now I understand that ADA4627-1 is soooo transparent sounding in my PPAV2.

 I could now try Intersil EL1516, that is one of my exocit and superfast op amps. 
 Luckily those 33 ohm output resistors on the X-FI layout slow op amps considerably and there is lot of compensation in the feedback loop too so EL1516 should work. I wish for extremely wide soundstage with precise detail and crisp mids, plus tight bass!


----------



## Spacehead

These modern op amps are so good that their performance doesn't suffer so badly from bad conditions, long wires with lot of capacitance and inductance. 
 I made a single to dual converter carrier and installed it with OPA1611 x 2 to my so hard modded X-FI Fatality 
	

	
	
		
		

		
		
	


	













 loopback Test results (LM4562 input op amp as always)
 results gets a little worse as more wire gets added.
http://i42.tinypic.com/25zh0jn.jpg
 RMAA
 General performance Very good

 BTW OPA1611 has pretty smooth sound or I am just tired?


----------



## ROBSCIX

The OPA1611 has smooth sound. Great stuff.


----------



## netsky3

Who knows the OPA2132 / 2134??


----------



## netsky3

Who knows the OPA2132-34?


----------



## leeperry

never heard of it


----------



## joe_cool

Quote:


  Originally Posted by *netsky3* /img/forum/go_quote.gif 
_Who knows the OPA2132 / 2134?? 
	

	
	
		
		

		
		
	


	


_

 

Just in case you're serious: TI/Burr-Brown


----------



## netsky3

Quote:


  Originally Posted by *joe_cool* /img/forum/go_quote.gif 
_Just in case you're serious: TI/Burr-Brown_

 

I know that page, i would like to know its sound and if is good to drive headphones


----------



## joe_cool

Quote:


  Originally Posted by *netsky3* /img/forum/go_quote.gif 
_I know that page, i would like to know its sound and if is good to drive headphones 
	

	
	
		
		

		
		
	


	


_

 

My opinion is not so good but here is an objective article: Tangent


----------



## SpudHarris

I still like the OPA132AU as recommended by your friend and mine Andrea


----------



## leeperry

OPA2132P is a very cheap solution for hifi sound IMHO...if you can use LT1364 to feed it, it will sound fantastic to most non-OCD'ed ppl
	

	
	
		
		

		
			





 I regularly exchange emails w/ Andrea, it's a shame he's banned on so many forums


----------



## SpudHarris

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I regularly exchange emails w/ Andrea, it's a shame he's banned on so many forums 
	

	
	
		
		

		
		
	


	


_

 

x2 I quite enjoyed the banter and enjoyed trying some of his ideas...


----------



## joe_cool

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_OPA2132P is a very cheap solution for hifi sound IMHO..._

 

I believe the OPA2132P and OPA2132AP are out of production. Only the SMD versions are available.


----------



## leeperry

well, it's not world class either...it's just a good cheap opamp for non too demanding ppl.

 anyway, I just went from this: 

 to this: 



 there is no question that the sound is clearer and less distorted(I used Cardas eutectic solder, and the highest grade of gold plated Mill-Max sockets on the left picture) w/o the additional sockets(they're fed ±12V from a linear regulated DPS) 
	

	
	
		
		

		
		
	


	




 there's an audio repair shop owner around my place who told me that ditching sockets was a necessary evil, and that they should only be used for deciding about a final choice...he said it'd cost me $15/20 bucks for him to ditch sockets using a hot air gun and stuff...I'll go there ASAP, as nothing tops that holy 1028A to my ears anyway 
	

	
	
		
		

		
		
	


	




 and tomorrow I'm getting a tube amp, a new era of rolling is arising: Little Country III Tube Headphone Amplifier

 yummy 
	

	
	
		
		

		
		
	


	




 :


----------



## ROBSCIX

Quote:


  Originally Posted by *netsky3* /img/forum/go_quote.gif 
_Who knows the OPA2132-34?_

 

Both are really considered generic audio opamps now. Reasonable "burr-brown" sound signature that many like.
 They have tubby type of bass and glossy high range...reasonable for audio for many designers but there are higher grade units out there.
  Quote:


  Originally Posted by *joe_cool* /img/forum/go_quote.gif 
_I believe the OPA2132P and OPA2132AP are out of production. Only the SMD versions are available._

 

I think many just went to the OPA2134 for a similar sound. Some like those better and some do not.


----------



## netsky3

Quote:


  Originally Posted by *joe_cool* /img/forum/go_quote.gif 
_My opinion is not so good but here is an objective article: Tangent_

 

 Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I still like the OPA132AU as recommended by your friend and mine Andrea 
	

	
	
		
		

		
		
	


	


_

 

 Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_OPA2132P is a very cheap solution for hifi sound IMHO...if you can use LT1364 to feed it, it will sound fantastic to most non-OCD'ed ppl
	

	
	
		
		

		
		
	


	




 I regularly exchange emails w/ Andrea, it's a shame he's banned on so many forums 
	

	
	
		
		

		
		
	


	


_

 

Thanks..
 I've bought a 2134 for few dollars on ebay, i'll use on my oatley kit.
 The stock opamp is worse in any case


----------



## leeperry

humm 2134P/PA are unbearable compared to 2132P...there are 4 chips coming from the same waffer, 2132P is the highest grade of the 4(and it's audible too!)

 but better, put two OPA132U on a browndog...better stereo separation


----------



## Spacehead

I haven't listened OPA2132 for awhile. But I think they are muddy in the bass section but easy to listen, not too many details, highs are fuzzy and not exact or sharp, but punchy.

 BTW I epoxied that DIP to SOIC tower to my X-FI PCB. The solder joints are now under thick layer of epoxy, but they are shiny and conduct very well. At least these results speak for good contact.
http://i39.tinypic.com/1zx4d1e.jpg
 THD is 0.0016% with ADA4898-1

 Actually it is so transparent experience (ADA4627-1 on PPAv2) that I get listening fatigue pretty fast. I don't know if I should make the sound worse somehow 

 I am pretty proud that I can do what bichi can do (to X-FI). I lose some technical quality because I am just practicing and don't have sharp enough iron tip.


----------



## Spacehead

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_I'll go there ASAP, as nothing tops that holy 1028A to my ears anyway 
	

	
	
		
		

		
		
	


	




 and tomorrow I'm getting a tube amp, a new era of rolling is arising: Little Country III Tube Headphone Amplifier

 yummy 
	

	
	
		
		

		
		
	


	




 : 
	

	
	
		
		

		
		
	


	


_

 

Oh is that LT1028 so heavenly good? Isn't that pretty old op amp (datasheet says 1992?) ?

 What kind characteristic that LT1028 have? Can you hear it, or is it clear as just washed window? 

 The more transparent op amp is, the harder it is to evaluate the sound characteristics. 


 Oh tube rolling would be way to high distortion when compared to good op amps.


----------



## joe_cool

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_http://i39.tinypic.com/1zx4d1e.jpg
 THD is 0.0016% with ADA4898-1_

 

Awesome attachments! Most posters around here get lost (or lose interest?) when I post supporting documents.


----------



## leeperry

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_Actually it is so transparent experience (ADA4627-1 on PPAv2) that I get listening fatigue pretty fast. I don't know if I should make the sound worse somehow _

 

yes, a lot of those uber-low THD+N opamps quickly become unbearable to listen to...anyway, I'm floored by the SQ of 1028A w/o sockets, oh my oh my 
	

	
	
		
		

		
		
	


	




 Andrea tells me that soldering them on the board for good might rise regrets afterwards, haha...sounds about right!


----------



## leeperry

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_Oh is that LT1028 so heavenly good? Isn't that pretty old op amp (datasheet says 1992?) ?

 What kind characteristic that LT1028 have? Can you hear it, or is it clear as just washed window? 

 The more transparent op amp is, the harder it is to evaluate the sound characteristics. 

 Oh tube rolling would be way to high distortion when compared to good op amps._

 

I think majkel nailed it down pretty well in his comparison thread: http://www.head-fi.org/forums/f6/aud...1/#post5238657

 well, experience has taught me that measurements don't mean jack as far as SQ is concerned....and that newer hardly ever means better either in the audio world 
	

	
	
		
		

		
		
	


	




 the 1028A is well worth a roll IMHO, it is most likely going to stay in my Spitfire DAC for a (long) while...it just sounds heavenly good 
	

	
	
		
		

		
		
	


	




 it's got very analog sounding and highly detailed mids, highly percussive low end bass, a triangular shaped SS that's too awesome on headphones(free xfeed my friend 
	

	
	
		
		

		
		
	


	




), and the trebles are slightly recessed(which is great on headphones) yet very detailed.

 Ray Samuels tried to put it in words too: REVIEW: Ray Samuels Emmeline HR-2 - SGHeadphones
  Quote:


 As Mr. Samuels once remarked, the LT1028 is like putting sugar all over your sound. It has a very liquid, sweet, and warm midrange that exhibits sharp bass and treble roll off. Unlike the Analog Devices op-amps, it is not dark. In fact, low level details flow through with greater clarity and definition.


----------



## ROBSCIX

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_I haven't listened OPA2132 for awhile. But I think they are muddy in the bass section but easy to listen, not too many details, highs are fuzzy and not exact or sharp, but punchy.

 BTW I epoxied that DIP to SOIC tower to my X-FI PCB. The solder joints are now under thick layer of epoxy, but they are shiny and conduct very well. At least these results speak for good contact.
http://i39.tinypic.com/1zx4d1e.jpg
 THD is 0.0016% with ADA4898-1

 Actually it is so transparent experience (ADA4627-1 on PPAv2) that I get listening fatigue pretty fast. I don't know if I should make the sound worse somehow 

 I am pretty proud that I can do what bichi can do (to X-FI). I lose some technical quality because I am just practicing and don't have sharp enough iron tip._

 

Yes, I find many of the Burr-Brown opamps have a similar signature. The "burr Brown" sound. I have heard it described as tubby bass and glossy high range.
 There are much higher quality units to be found then the 2132 or 2134...


----------



## Spacehead

I will get three OPA637 tomorrow.

 Those are my first OPA627/OPA637 op amps.


 I was bit hasty and didn't understand that I would need them both to my amplifier and to my source (X-FI dac filter).

 Where you think I should put them if I wanted to hear them?

 I think ADA4898-1 is extremely transparent, but a bit dark and sterile (bipolar) on my X-FI. 

 On my PPA v2 I have ADA4627-1 which is more fluent and kind of softer, being a JFET amplifier.

 I want to have good feel how OPA637 sound but it seems so difficult to distinct it from either of these ADA4627-1 or ADA4898-1 

 I think ADA4627-1 is more transparent one. 

 But where to put OPA637AU? 

 BTW. Extremely cheap I got them, only 2.68€ piece!!


----------



## netsky3

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_BTW. Extremely cheap I got them, only 2.68€ piece!!_

 






 ...but...where????


----------



## Spacehead

Quote:


  Originally Posted by *netsky3* /img/forum/go_quote.gif 
_






 ...but...where????_

 

omg if I post this here, soon they cost 30€ :O

 Serving the community: 

Partcon Verkkokauppa


----------



## netsky3

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_omg if I post this here, soon they cost 30€ :O

 Serving the community: 

Partcon Verkkokauppa_

 

LOL!
 damn is a shop in norway


----------



## leeperry

OPA637 is only stable for >4 gain, many designs can't get it to stabilize: Auzentech OPAMPS

 OPA627BP is prolly your best choice


----------



## Spacehead

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_OPA637 is only stable for >4 gain, many designs can't get it to stabilize: Auzentech OPAMPS

 OPA627BP is prolly your best choice 
	

	
	
		
		

		
		
	


	


_

 

I use OPA552 succesfully in my PPA when I set gain to 5. So I assume the OPA637 works too. 

 I think in X-FI op amp works in inverting mode and gain is pretty low, about -3 I guess.


----------



## leeperry

oh sure, if you know what you're doing you can get any opamp to work anywhere....but for the average blind roller, OPA637 might easily end up being a total failure.


----------



## Spacehead

Quote:


  Originally Posted by *netsky3* /img/forum/go_quote.gif 
_LOL!
 damn is a shop in norway 
	

	
	
		
		

		
		
	


	


_

 

Actually in Finland. Too bad I couldn't help you, this message in front page: "And please note that we deliver only to Finland"

 Should I buy dozens of them and do some ebay selling


----------



## joe_cool

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_OPA627BP is prolly your best choice 
	

	
	
		
		

		
		
	


	


_

 

I bought a pair of OPA627BP and tried them in my DAC as diff-to-single-ended output buffers and found them too "soft" for jazz and rock. Maybe for classical they would be just right; I should have tried that, I do have some.


----------



## leeperry

well I read that OPA867 was an improved version of 627, and I really didn't like it...I cannot stand those OPA/LME opamps anyway, they do everything wrong to my ears


----------



## ROBSCIX

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_I use OPA552 succesfully in my PPA when I set gain to 5. So I assume the OPA637 works too. 

 I think in X-FI op amp works in inverting mode and gain is pretty low, about -3 I guess._

 

To Clarify, the OPA637 is stable for gains =>5 as mentioned in the spec sheet.


----------



## ROBSCIX

Quote:


  Originally Posted by *joe_cool* /img/forum/go_quote.gif 
_I bought a pair of OPA627BP and tried them in my DAC as diff-to-single-ended output buffers and found them too "soft" for jazz and rock. Maybe for classical they would be just right; I should have tried that, I do have some._

 

They are favorites to many people. I think it depends on other factors in the design. Some like them because they are smooth and soft as you said. Personally I like the OPA637 more if compatible in the same circuit.


----------



## Mad Max

Quote:


  Originally Posted by *ecclesand* /img/forum/go_quote.gif 
_I have a set of the AD744KN in my Parasound DAC. I did the output bypass mod and they sound fantastic. Did you do the same with yours or stock? I should give the metal can versions a try with the output bypass._

 

I tried output bypass with AD744 JN, KN, and AH and the mod changes the midrange tonality, killing their synergy with my ipod. Other than that, they sound great. I find that all three grades of 744 differ in their midrange tonality, but the metal can and plastic dip versions are very close to being the same and synergize best with my 6G ipod classic. The ceramic dip doesn't synergize quite as well.


----------



## ROBSCIX

..always another flavor!


----------



## Mad Max




----------



## 12Bass

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I still like the OPA132AU as recommended by your friend and mine Andrea 
	

	
	
		
		

		
		
	


	


_

 

Have a pair on a BrownDog... and don't find them much different than an OPA2132P. Not in the same class as OPA827, IMO.


----------



## ROBSCIX

Yeah, the OPA827 is a very good sounding opamp. Just made a set for a freind for his circuit.

 In your opinion how do you think they compare to the OPA627?


----------



## 12Bass

Never tried OPA627.... too rich for my blood! Plus, others whom I respect seemed to think that the OPA827 surpassed it, at lower cost, so I didn't see the point.


----------



## ROBSCIX

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Never tried OPA627.... too rich for my blood! Plus, others whom I respect seemed to think that the OPA827 surpassed it, at lower cost, so I didn't see the point._

 

I have read that in a few places, I think they sound different though.
 Maybe they are marketed to be the next in the series. They are great little units though I have a few built for myself and buddies keep asking for them also.


----------



## Spacehead

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Never tried OPA627.... too rich for my blood!_

 

I got 4 OPA637 for 10 euros!! 

 That is so cheap. I hope to get them working, on my X-FI and on my PPA v2 at the same time. Then I can compare them to 
 AD8599, AD8620, AD8066, OPA1611, ADA4898-1, ADA4627-1 
 those op amps characteristics I remember pretty well.


----------



## ROBSCIX

Hmm, hope they are real OPA637's. If you are unfamiliar with that chip it has no internal compensation so it requires higher gains to provide stable operation.


----------



## Spacehead

OK OPA637 didn't work on my Sound Blaster X-FI

 I installed ADA4627-1 instead and it works fine. RMAA test results http://i39.tinypic.com/a27v6d.jpg

 My X-FI looks like this: http://i43.tinypic.com/335f3ic.jpg

 Are these real OPA637?






 The web store I bought them from, is reputable, so I think they are real. 

 I had AD8597 on my PPA v2 for reference just before I installed OPA637. On the ground channel I have another JFET op amp, AD8620 (on dual to single adapter)

 OPA637 sounds quite delicate 
 It is slower kicking than AD8599 but still keeps the rhythm very well. Like a good jazz drummer. 
 The bass is VERY heavy compared to AD8599. Details are all intact, nothing is hidden. It isn't overwhelming though. 
 I sense some echoing, more 3D soundstage, not too wide though. 
 I might be little biased because I was so sure that this would be excellent sounding op amp. And it is. 
 If I think OPA2132 is slow and muddy. This is relaxed and fast at the same time. Highs aren't overly bright. Sound isn't dark overall.
 I think this doesn't remind me of any op amp I have tried. Bass is tight. Mids are strong but soft and exact. Claps sound most realistic I have ever heard them. It has OPA637 sound 
	

	
	
		
		

		
		
	


	





 These thoughts come from Above mentioned sound card and highly class a biased PPA v2. 
 ADA4627-1 is most transparent op amp I have, so I have removed it's influence from the sound signature of OPA637. Ground channel op amp doesn't influence sound too much.


----------



## buz

So I came around trying my LT1028C in my NG98. I think it sounds "faster" and more forward with the D2000 which is quite a welcome change. Bass impact likely also got stronger which is good thing for a bass head like myself

 Now I just need to fix gain to get a little more flexibility with the volume knob and may actually delay buying an amp


----------



## radiohlite

I've got a CMoy with OPA2227 I'm not entirely happy with. Listen mainly to classical (orchestral). What opamp would better suit this?


----------



## leeperry

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_So I came around trying my LT1028C in my NG98. I think it sounds "faster" and more forward with the D2000 which is quite a welcome change. Bass impact likely also got stronger_

 

a friend of mine tried 1028AC in his NG27 and all it does is hissing 
	

	
	
		
		

		
		
	


	




 yes, its low end bass tightness is amazing 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *radiohlite* /img/forum/go_quote.gif 
_I've got a CMoy with OPA2227 I'm not entirely happy with. Listen mainly to classical (orchestral). What opamp would better suit this?_

 

try an adapter w/ two OPA827/OPA132U maybe?


----------



## Spacehead

Quote:


  Originally Posted by *radiohlite* /img/forum/go_quote.gif 
_I've got a CMoy with OPA2227 I'm not entirely happy with. Listen mainly to classical (orchestral). What opamp would better suit this?_

 

OPA627 would sound classical


----------



## radiohlite

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_OPA627 would sound classical_

 

classical in what sense? I'm running some Grados out of it (heavily modded: they actually have bass and soundstage) so the one thing I don't want is more brightness. I've read OPA2227 is bassy & slow, but in this setup there's what I can only describe as 'digital glare', you know, the way early 80s digital recordings sound? It's not a FR problem, I think. I guess it's just the way this particular opamp sounds (I've also tried it with V6, HD600, K701, and D2000, but it's more pronounced with the Grados.)


----------



## Spacehead

Quote:


  Originally Posted by *radiohlite* /img/forum/go_quote.gif 
_classical in what sense? I'm running some Grados out of it (heavily modded: they actually have bass and soundstage) so the one thing I don't want is more brightness. I've read OPA2227 is bassy & slow, but in this setup there's what I can only describe as 'digital glare', you know, the way early 80s digital recordings sound? It's not a FR problem, I think. I guess it's just the way this particular opamp sounds (I've also tried it with V6, HD600, K701, and D2000, but it's more pronounced with the Grados.)_

 

I assume that OPA637 sounds very similar to OPA627. They should be very similar to each other, only difference being the amount of internal compensation (which then leads to difference in specs)

 OPA637 is slow but accurate. Mids detail is excellent with this op amp. It sounds more effortless. Soundstage feels more present. Bass doesn't sound boomy but it isn't light. Colorations are neutral, it doesn't feel dark or bright. 

 I tried to listen some classical songs, but I think my headphones cannot handle that task. 
 I tried to get a sense what would string instruments sound like with this op amp. I think the sound is detailed enough to tell what kind of wood is used on instruments body. The reflections are very realistic with this op amp. 

 But anyway I can recommend trying this.

 Then there are ADA4898-1 and ADA4627-1 that reproduce at such accuracy that it can start to sound boring.


----------



## foureight84

can bad / fake opamps harm your speakers?


----------



## joe_cool

Quote:


  Originally Posted by *foureight84* /img/forum/go_quote.gif 
_can bad / fake opamps harm your speakers?_

 

Can greedy investment banks mess up your life savings? It's hard to say no to such an open-ended question. Poor quality control and outright fraud are both a problem IMO. I often tell myself "safety is no accident" and take appropriate precautions when working with expensive equipment.

 Getting closer to 1000 posts! I need a real life...


----------



## 12Bass

Quote:


  Originally Posted by *foureight84* /img/forum/go_quote.gif 
_can bad / fake opamps harm your speakers?_

 

If the fakes are just some cheap op amp like a TL072 or NJM4558, then probably not.... as long as bias currents (and DC offset) aren't a problem. But that assumes that the counterfeiters are using op amps and not something else....


----------



## ROBSCIX

I find the OPA637s have more high end extension then the 627's.
 The 637 has a much higher slewrate...


----------



## Spacehead

My PPA V2 gave out some hiss because of the high gain the OPA637 needed. 
 I lowered the gain to unity and installed LME49860. 

 LME49860 required that input impedances are balanced pretty closely or there would be about 100 mV (or more) DC Offset. 

 LME49860 sounds pretty good in my PPAV2. The soundstage is closer than OPA637. Highs are snapping but they aren't disturbing bright. Bass is balanced, not too heavy or too light. Pretty neutral presentation. Maybe less colored op amp. I have ADA4898-1 in my X-FI so sound is all bipolar. I have used to somewhat dark sound coming from bipolars but this feels neutral in that regard too. I have to check if offset shifts when the amplifier warms up. LME49860 could sound a little grey, dull, and lifeless. Maybe it is coloration or just accurate.

 I wish that I hadn't ever even tried how another op amp sounds. How I can cure this disease. I see that Andrea is into op amps too, is the overly enthusiastic approach reason for a ban? 
 I can cure myself by building a discrete amplifier next. 

 I have a 3 transistor amplifier and it sounds super. Then I need to get a dac that has passive IV and discrete buffer. 

 The gurus here, can you tell how to gain some kind of introspect into op amp listening? Another set of headphones? Or is this op amp rolling sane thing to do at all?


----------



## Spacehead

OPA2613:





 presentation is close
 accurate
 not annoying
 pleasant
 not warm
 not dark
 bit messy
 a little HARD (in a good way)

 in X-FI differential to single ended converter + filter, heard through PPAv2 ADA4627-1ARZ + LME49860 on ground

 I have no means to measure if high speed op amps oscillate or misbehave on X-FI, I guess it is fairly well compensated if op amp just can drive capacitive loads. and this one should be able to do that.

 It passes RMAA test, so it should behave well in audio band?
http://i41.tinypic.com/1zmfnmb.jpg

 X-FI: http://i43.tinypic.com/sces1z.jpg

 This op amp is pretty cold for BB op amp, but not bad... not great either, but that might indicate good transparency 
	

	
	
		
		

		
		
	


	




 I chose to try to this over OPA2674 or OPA690, I guess those op amps don't work in that circuit. 
 The dip to soic adapter is so well epoxied to the card that I might burn an op amp in it someday


----------



## murrays

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_OPA2613:
 I have no means to measure if high speed op amps oscillate or misbehave on X-FI, I guess it is fairly well compensated if op amp just can drive capacitive loads. and this one should be able to do that._

 

If you don't have access to an oscilloscope (the best way to check) there is always the rule of thumb. Test how hot it gets with the end of your finger. A chip fully oscillating above the audio band (typcally ~ 1MHz) will get very hot - most of its power will be driving frequencies that you can't hear. Normally most chips only get lukewarm. If music is playing, an oscillating opamp will "broadcast" (modulate) RF - I have heard that you can tune in to it with an adjacent AM radio. I have yet to try this for myself as I have carefully stabilised my amps, but will try it out when I have one that oscillates. Has anyone else here tried that one?


----------



## Spacehead

Quote:


  Originally Posted by *murrays* /img/forum/go_quote.gif 
_If you don't have access to an oscilloscope (the best way to check) there is always the rule of thumb. Test how hot it gets with the end of your finger. A chip fully oscillating above the audio band (typcally ~ 1MHz) will get very hot - most of its power will be driving frequencies that you can't hear. Normally most chips only get lukewarm._

 

Nice, this one (OPA2613) is about as warm as my finger. Sometimes oscillating chip sounds very hard and harsh. 
 But anyway OPA2613 has "GAIN BANDWIDTH PRODUCT: 125MHz". That isn't overly much. 
 About it's distortion. In differential configuration, 100 kHz and -105 dB THD and it get's lower. That is pretty low, right?
 When I ordered these I thought only about the high output current, limited to 500 mA. But other specs are on par too, 1.8nV/sqrtHz input noise voltage is very low too.


----------



## leeperry

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_(OPA2613) is about as warm as my finger._

 

well, how warm's your finger then? 
	

	
	
		
		

		
		
	


	




 yes, Andrea was banned on diyaudio.com for no reason, except being obsessed about opamp rolling...these ppl listen to their oscilloscope and datasheets, they can't quite grasp the idea that all the opamps sound different 
	

	
	
		
		

		
		
	


	




 and you were right about tubes sounding "tubey" hummmmkay, but I've found a nice "in-between" solution: http://www.head-fi.org/forums/6565903-post442.html


----------



## ROBSCIX

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_Nice, this one (OPA2613) is about as warm as my finger. Sometimes oscillating chip sounds very hard and harsh. 
 But anyway OPA2613 has "GAIN BANDWIDTH PRODUCT: 125MHz". That isn't overly much. 
 About it's distortion. In differential configuration, 100 kHz and -105 dB THD and it get's lower. That is pretty low, right?
 When I ordered these I thought only about the high output current, limited to 500 mA. But other specs are on par too, 1.8nV/sqrtHz input noise voltage is very low too._

 

Sometimes they osciallate outside of the audible bandwidth so trying to listen for anomolies is no good in this case. You can use the heat test as describe by others or you can pull out the pencil and paper and compare how much current it should be drawing to how much it actually is drawing. If the opamps is osciallting it is drawing way too much current as this is the cause of the extra heat.


----------



## theSeekerr

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_yes, Andrea was banned on diyaudio.com for no reason, except being obsessed about opamp rolling...these ppl listen to their oscilloscope and datasheets, they can't quite grasp the idea that all the opamps sound different 
	

	
	
		
		

		
		
	


	


_

 

Andrea was banned for making contradictory claims, including claims about opamps he'd never heard.

 As for whether opamps sound different....well, certainly they can, but assuming an opamp is matched to its application, the differences are far less profound than is often claimed here.


----------



## leeperry

Quote:


  Originally Posted by *theSeekerr* /img/forum/go_quote.gif 
_As for whether opamps sound different....well, certainly they can, but assuming an opamp is matched to its application, the differences are far less profound than is often claimed here._

 

well, most ppl in this thread would strongly disagree w/ this statement, as it couldn't be farther from the truth IME.

 and noone even mentioned to Andrea why he had been banned all of a sudden, tough luck...we can all change, he could have improved his behavior if asked so...anyway he's living well now and doesn't care much I think


----------



## 12Bass

Quote:


  Originally Posted by *theSeekerr* /img/forum/go_quote.gif 
_As for whether opamps sound different....well, certainly they can, but assuming an opamp is matched to its application, the differences are far less profound than is often claimed here._

 

Hmmmm.... I'd say that op amps make less of a difference than transducers, though if a system is sufficiently revealing, such differences can often be easily detected. Moreover, I'd often appreciate it if I didn't hear any differences, as it would keep me from trying to find something which sounds better.


----------



## theSeekerr

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Moreover, I'd often appreciate it if I didn't hear any differences, as it would keep me from trying to find something which sounds better._

 

Might I politely suggest ABX testing? Yes, it'll require you to build up 2 identical amps to AB, and that's a pain, but still.

 "But ABX testing is flawed - because it *insert your own excuse here*, I can't hear things which I know to be true!"

 Just because you hear a difference doesn't mean it exists.

 Don't worry, I won't post in here again, this thread doesn't need to hear this debate play out again. Anyone is welcome to PM me if they want to argue on their own time.


----------



## Mad Max

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_The gurus here, can you tell how to gain some kind of introspect into op amp listening? Another set of headphones? Or is this op amp rolling sane thing to do at all?_

 

You could try the RE0 as far as 'phones. *Very* transparent earphone.
 My AD700 is very sensitive to treble extension, and soundstage changes as well though seemingly to a somewhat lesser extent.


----------



## qusp

yes leeperry, I know you are brothers in arms and everything, but thats some serious rose coloured glasses you got on there, i'm surprised you can see at all.

 just soldered in some OPA827 again in place of the stock opamps for the DC servos on my dual mono QRV08, destined for the output stage of my ackodac sabre32 dac. the servo only has an audible effect down low in the bass regions and I found OPA827 to have the most amazing clean yet slightly musical (natural is probably the word) bass

 using AD825 in the 8 onboard jung super regulators. the build should be finished in the next couple of weeks and will make sure to post impressions of them in this placement. the amp section itself is discrete SMD


----------



## leeperry

Quote:


  Originally Posted by *theSeekerr* /img/forum/go_quote.gif 
_Might I politely suggest ABX testing?_

 

hehe well, all the opamps sound different..they just do, believe me we really wish they didn't 
	

	
	
		
		

		
		
	


	




 this guy says that 4562/1028 sound identical to him: The best sounding audio integrated opamps - diyAudio

 I'd suggest retiring from the audio hobby completely, and do something more rewarding w/ his time.


----------



## buz

I'm starting to think the LT1028C has too much bass. I even started eq'ing down the bass on my D2000 - sure as hell the first time in my life I ever did that 
	

	
	
		
		

		
		
	


	




. Heck it even brings out bass in the RE0...

 Maybe try a somewhat colder, analytic, very transparent opamp. Any suggestions?


----------



## 12Bass

Quote:


  Originally Posted by *theSeekerr* /img/forum/go_quote.gif 
_Might I politely suggest ABX testing?_

 

I have done some single-blind testing and been able to reliably tell the difference between devices. Generally, I am a proponent of the scientific method.


----------



## Spacehead

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_I'm starting to think the LT1028C has too much bass. I even started eq'ing down the bass on my D2000 - sure as hell the first time in my life I ever did that 
	

	
	
		
		

		
			





. Heck it even brings out bass in the RE0...

 Maybe try a somewhat colder, analytic, very transparent opamp. Any suggestions?_

 

bipolar ADA4898-1 
 jfet ADA4627-1

 also pretty analytical and colder: AD8022, AD8066


----------



## buz

Forgive my ignorance, but what would the difference between JFET and bipolar be?


----------



## Spacehead

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_Forgive my ignorance, but what would the difference between JFET and bipolar be?_

 

Bipolar input op amps cannot tolerate differences in their input impedances so well. 
 If + input is 100K and - input 1K then bipolar op amp will generate DC offset due to high input bias currents. 
 JFET input op amps can tolerate this error very well and don't generate DC offset because their input bias currents are low.

 This is my understanding about this much more complicated matter. 

 Bipolar op amps sound more classy to my ears. JFETs are like pop music, little compressed sounding.


----------



## ROBSCIX

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_Forgive my ignorance, but what would the difference between JFET and bipolar be?_

 

Different internal construction.


----------



## buz

So after listening to the LT1028C some more, I am getting used to the deeeep strong bass (always have been always will be a basshead). I think I rather need to fix the gain of the amp section than mess around with opamps much more. Should probably go get a soldering kit and a clue bat for my self 
	

	
	
		
		

		
		
	


	




. 

 Or just go and buy that M-Stage, although with the bloody volcano still active, I doubt it could even be shipped to me 
	

	
	
		
		

		
		
	


	




 Edit: >< this close to buy it. Now of course I wonder what opamp I could put into the DAC to feed it LT1028C in DAC and headphone amp may be a little too much


----------



## Spacehead

I got my SMD CMOY working. Completely silent amp with gain of 3. 

 so easy to listen to that I cannot find too many special characteristics from this op amp:





 here is what I thought:
 sloppy?
 good current output , can drive 32 ohm headphones
 tight
 bass is nice
 very easy to listen
 not too many details
 pretty generic sounding op amp
 good thing is though that it doesn't color the sound. but very boring if one wants to listen to op amps. 

 Maybe it was limited by my ground channel which is open loop class ab buffer with Panasonic FC output caps. closed loop buffers sound a lot better. 

 The performance of this amplifier is of course very good for the simplicity, I think I'll start making these for sale.


----------



## ROBSCIX

The 4556 are condsidered cheap generic opamps. I doubt you will find too many great points about those. They are usually used for their price, they are a jellybean opamp.


----------



## ROBSCIX

double post, darn site!


----------



## buz

Is there any place to get LT1028A (preferably on a DIP8 dual adapter) and LME49880 at reasonable prices (as well as DIP8 AD8022/66)? Ebay does not seem to have any... Still thinking about those AD797BR, too.


----------



## 12Bass

Saw these in another thread.... though I have some skepticism due to NJR's previous devices:

-MUSES Official Website-"MUSES Series" high quality sound bipolar-input dual operational amplifier


----------



## Spacehead

I got cured! I bought worse headphones with inferior resolution, Philips SHP2500. With them on I have yet found myself wondering how would this song sound with another op amp, because, I bet I couldn't hear the difference!

 But when I actually will try different op amps with those headphones, will I hear something different...?


----------



## leeperry

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_I got cured! I bought worse headphones with inferior resolution, Philips SHP2500._

 

you're a great problem solver 
	

	
	
		
		

		
		
	


	




 anyone tried this guy's adapters? http://shop.diyrealaudio.com/product...roducts_id=851

 the guy who runs that browndog company told me that he's almost deaf, and that ebay seller says that the design of the browndog's is just terribly wrong: Dual SOIC to DIP-8 Convert PCB Adapter SMD OPA627 - eBay

 I think I'll solder 2*LT1028ACN8 on the former link's adapter, and compare to its browndog counterpart


----------



## 12Bass

Have considered buying some of those HK adapters, but don't need any at the moment. A comparison would be interesting.


----------



## Mad Max

Would be nice if their single soic-to-dip8 boards had the leads and pins perpendicular like that.


----------



## leeperry

oh, I didn't realize that the bottom pins were not in the center like on the browndog...so that means that the audio path of one channel is longer than the other? hummmm, very strange idea


----------



## Mad Max

Not really, it's the same situation with the PD adapters I've got and some others I've seen online.


----------



## ROBSCIX

There are quite a few places that make adapters of varying quality. I suggest trying out various units from different sources until you find the units that give you what you want for a good price.


----------



## buz

Is there any source from where I can get LME49880, AD8022 and AD8066 on dual DIP8 adapters? I sure don't want to solder....


----------



## buz

Is there any source from where I can get LME49880, AD8022 and AD8066 on dual DIP8 adapters? I sure don't want to solder....


----------



## leeperry

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_Not really, it's the same situation with the PD adapters I've got and some others I've seen online._

 

so the "shorter" side has longer traces on purpose? I find it clumsy, I'll look for other alternatives.


----------



## buz

To be fair, as electrons in copper travel at at roughly 0.6-0.7c I don't think you would notice much of difference...


----------



## jezz

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_To be fair, as electrons in copper travel at at roughly 0.6-0.7c I don't think you would notice much of difference..._

 

It is worthwhile to try to reduce the distance between components if only because of parasitic capacitance. I've seen a few testy opamps oscillate because of it (such that they couldn't be mounted in a socket and needed to be mounted directly on a board). An exaggerated example of this is present in Gainclone amplifiers' feedback loops.


----------



## joe_cool

Quote:


  Originally Posted by *jezz* /img/forum/go_quote.gif 
_It is worthwhile to try to reduce the distance between components if only because of parasitic capacitance. I've seen a few testy opamps oscillate because of it (such that they couldn't be mounted in a socket and needed to be mounted directly on a board). An exaggerated example of this is present in Gainclone amplifiers' feedback loops._

 

Perhaps one way to address this is to put a bypass cap across the power supply leads on the adapter itself?


----------



## leeperry

last time I tried adding 0.1uf caps on V+/V-, all it did was killing the low end bass percussion...I don't want to fix issues due to design faults. I also don't like the asymetrical pressure it'll put on the socket..

 I've never been happy w/ the 2*SOIC8>1*DIP8 browndogs, but the 2*DIP>1*DIP8 have always sounded great IME anyway..


----------



## Spacehead

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_you're a great problem solver 
	

	
	
		
		

		
			



_

 

Yeah I have rolled a lot of op amps now and couldn't detect much of differences. Some have better bass response, some are just more musical. 
 SHP2500 is not bad headphone but it just don't have that resolution that is needed to detect op amp differences. I can enjoy music a lot more when I am not troubled by too many details. 
	

	
	
		
		

		
		
	


	



 Next week I get KSC75, I wonder if those are good enough for minor details. 

 I have now OPA2211 on my X-FI and ADA4627-1 on PPAV2 left and right, AD8620 on ground channel and OPA1642 on DC servo.


----------



## Mad Max

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_last time I tried adding 0.1uf caps on V+/V-, all it did was killing the low end bass percussion...I don't want to fix issues due to design faults. I also don't like the asymetrical pressure it'll put on the socket..

 I've never been happy w/ the 2*SOIC8>1*DIP8 browndogs, but the 2*DIP>1*DIP8 have always sounded great IME anyway.._

 

Have you tried measuring the resistance of the adapters/sockets? I'm pretty sure that matters quite a bit based on your observations.
 Doesn't appear to be an easy thing to do. The adapters I've got from diyinhk on eBay appear to have about 15k resistance. Confidence in my measurements is low, I'll just ask the seller, lol.


----------



## murrays

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_Have you tried measuring the resistance of the adapters/sockets? I'm pretty sure that matters quite a bit based on your observations.
 Doesn't appear to be an easy thing to do. The adapters I've got from diyinhk on eBay appear to have about 15k resistance. Confidence in my measurements is low, I'll just ask the seller, lol._

 

What points are measuring the resistance between? The contact resistance should all be below one ohm for each individual pin. Even going from IC socket to PCB track to adapter pin should still be less than one ohm. Also, there should be no connectivity at all between different pins of the adapter (e.g. 1-2, 2-3, 2-3, etc.) which means the meter should show "infinite" or "over range".
 However, if you measure them "in circuit" you will be measuring resistances of the surrounding circuit or the op-amp, rather than the adapter itself. This includes the case where the adapter is not in circuit, but has the chip inserted/attached - you will be measuring the chip.


----------



## Mad Max

I measured the pins. Yes, less than one ohm from socket to trace. No, no connectivity between pins, lol, I can get that much right. xD


----------



## murrays

Where was the 15k from?


----------



## Mad Max

A pin, lol.


----------



## Mad Max

A pin, lol.


----------



## leeperry

I indeed always have had very weird experiences w/ sockets+browndogs...it looks like a love/hate story


----------



## 12Bass

While there might be better designs, I have no major complaints about using a pair of singles on the BrownDog 020302. Sounds better than a dual....


----------



## Spacehead

Why you wonder about the qualities of a adapter. I think browndogs are superb quality compared to these:





 Those op amps sound cold and tight. Not much space, but good clarity. Bass is little light.


----------



## leeperry

well, time to move to single opamps my friend...duals always sound ugly.


----------



## Spacehead

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well, time to move to single opamps my friend...duals always sound ugly._

 

ok you are right. 
 I had deep Class A biasing too on my PPAv2 (4 mA). I have read that it could cause op amps sound analytical and cold (majkel wrote this). I possibly remove that circuit soon.


----------



## Mad Max

How come some of y'all use those dip sockets as adapters?
 Way too much solder going on there. Doesn't that affect the noise floor?


----------



## diditmyself

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well, time to move to single opamps my friend...duals always sound ugly._

 

I kind of agree. The question is why this is so.


----------



## diditmyself

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_How come some of y'all use those dip sockets as adapters?
 Way too much solder going on there. Doesn't that affect the noise floor?_

 

A socket shouldn't change the noise floor, or the sound, the slightest bit unless it makes it unstable. I think sockets are a necessity in the quest for the sound I'm after. If one roll opamps numerous times it will eventually destroy the PCB.


----------



## leeperry

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_I kind of agree. The question is why this is so._

 

dual mono is always a wiser choice than stereo, one of the basic rules of hifi? we could look for reasons...but TI tried to amend it, yet failed big time doing so 
	

	
	
		
		

		
		
	


	




Precision Amplifier - OPA1612 - TI.com
  Quote:


 The dual version features completely independent circuitry for lowest crosstalk and freedom from interactions between channels 
 

makes you wonder about those quad opamps 
	

	
	
		
		

		
		
	


	




 to me cables and opamps take a lot of magical thinking, because they all interact and sound different depending on their surrounding...and pretty much noone can explain why


----------



## Mad Max

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_A socket shouldn't change the noise floor, or the sound, the slightest bit unless it makes it unstable. I think sockets are a necessity in the quest for the sound I'm after. If one roll opamps numerous times it will eventually destroy the PCB._

 

I wasn't talking about the socket. -__-


----------



## ROBSCIX

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_I kind of agree. The question is why this is so._

 

A fact that was posted way back in the beginning of this thread but there is more to it. 
 Why? I think it has to do with isolation of the amplifers from each other.
 There is more to it technically but that is it, in a nutshell.
 I have been using dual single channel opamps in preference to dual channels for a long time. You will also find that many of the best audio opamps are single channel units.


----------



## ROBSCIX

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_I wasn't talking about the socket. -__-_

 

If you were refering to the single Vs. dual channel comments. It really depends on the unit. For many opamps a dual single channel module will soudn better and possibly produce better results in comparison to a single dual channel module.


----------



## Mad Max

I meant, doesn't that much excess solder affect the noise floor?


----------



## murrays

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_I meant, doesn't that much excess solder affect the noise floor?_

 

No.


----------



## Spacehead

Quote:


  Originally Posted by *Mad Max* /img/forum/go_quote.gif 
_How come some of y'all use those dip sockets as adapters?
 Way too much solder going on there. Doesn't that affect the noise floor?_

 

Cheap and easily available. There is some air that needs to be covered, that is why I need to use little more solder than would be needed for example on browndog adapter. As long as those neighbor pins don't short I am OK with with. If the joint is cold then It could affect the sound, but that wouldn't be round. 
 If my obsession would be very bad, I couldn't put my op amps to nothing but gold plated PCBs.


----------



## ROBSCIX

I prefer to use high end adapters. I build alot of opamps modules and I don't want them to be a point of possible failure because of a diy type of hack adapter.
 I am not saying those that do this are wrong, Hey the DIY spirit is great and they work for many people. Peronally I prefer to use adapters..
 I am not sure if I am obsessed but the adapters I use have gold plated traces and pins!


----------



## ROBSCIX

I prefer to use high end adapters. I build alot of opamps modules and I don't want them to be a point of possible failure because of a diy type of hack adapter.
 I am not saying those that do this are wrong, Hey the DIY spirit is great and they work for many people. Personally I prefer to use adapters...
 I am not sure if I am obsessed but the adapters I use have gold plated traces and pins!


----------



## Spacehead

I got DIP LT1028 as samples from Linear!! I was pretty surprised!
 Impossible to order them locally here. 

 I haven't listened very analytically for awhile so I guess it will be pretty hard to get good impression. I will compare to ADA4898-1 in my PPAv2.


----------



## leeperry

you know who forced me mentally to try OPA211ID again 
	

	
	
		
		

		
			





 majkel says they are the kings of space: http://www.head-fi.org/forums/f6/aud...-v-2-a-397691/

 they sound rather thin, but PRaT is still very much alive, and the SS is quite something indeed...it's funny how a good PSU and a clean environment scale really well w/ most opamps 
	

	
	
		
		

		
		
	


	




 LT1028A feels narrow in comparison.....god***** rolling!


----------



## leeperry

it's strange how there's a lot of nuances that were attenuated by LT1028A and become loud and clear on OPA211ID..it feels as the sound is a lot less distorted/colored 
	

	
	
		
		

		
		
	


	




 LT1028A seems to really color the lower mids and bass to death.


----------



## buz

I think the LT1028C boosted bass by a lot compared to the OPA2604 I was using before... Still wondering where to get AD8022/66 on DIPs...


----------



## leeperry

yes, but my phone is quite bass shy so it was kinda nice 
	

	
	
		
		

		
		
	


	




 I've been listening to OPA211ID for a little while now:
 -it seems fully able to drive my 32Ω headphones directly...LT1028AC was ear shredding bright and spikey in comparison.
 -the SS is very very wide and quite deep
 -the low end bass percussion is just as good
 -the bottom of the spectrum is far less bloated and "thick", the sound is far more aerial and less colored...it allows the mids to express themselves in a far clearer way 
	

	
	
		
		

		
		
	


	




 I'll try OPA827 again anytime soon 
	

	
	
		
		

		
		
	


	




 I previously tried all those chips in ±9V on a mid-range internal PC soundcard(noisy SMPS/EMI/dirty ground/etc), and now I run them in ±12V on a linear regulated DPS fed w/toslink in the Firestone Spitfire external DAC(that runs on a virtual ground design).

 Firestone told me that many ppl plug their phone directly to their Fubar2 RCA out, ideally I'd like to do the same on my Spitfire(used as PCM1793 LPF)...but they come stock w/ an OPA2604(35mA output current), and I'd rather not resort to NJM4580D 
	

	
	
		
		

		
		
	


	




*PS:* FWIR NJM4580 can output 50mA, OPA211 30mA...and my 32Ω phone would need ±24mA


----------



## 12Bass

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_...I previously tried all those chips in ±9V on a mid-range internal PC soundcard(noisy SMPS/EMI/dirty ground/etc), and now I run them in ±12V on a linear regulated DPS fed w/toslink in the Firestone Spitfire external DAC(that runs on a virtual ground design)..._

 

Not too surprising that you're noticing differences/improvement in tonality in another, higher quality, circuit. OPA211 remains one of my favorites.


----------



## leeperry

well, I still miss the thick sweet sound of LT1028AC...but the SS is much wider and clearer on OPA211ID(soo much better in movies!), and the mids are far less colored..duh!

 yeah, the SS is really amazing and PRaT is still every high...without "cheating"


----------



## Spacehead

I think OPA2211 has better soundstage than AD8620. I think I need to switch back to OPA2211 in my X-FI. 
 I want get some adjectives and thoughts about that LT1028ACN. I am trying to establish a base sound from ADA4898-1YRDZ first. On the ground is ADA4627-1ARZ
 I will soon swap to LT1028ACN. Maybe I need my more accurate phones (HD 438), but I'd like to try with these Philips SHP2500 first.


----------



## leeperry

buddy, give up on dual opamps altogether...their SS is always lousy.


----------



## Spacehead

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_buddy, give up on dual opamps altogether...their SS is always lousy._

 

ok I need to buy some adapters then. 

 It was quite a fiddling again with gain resistors for getting this to work. R4 is 51K, R3 15K

 Now listening music through:

 Sound Blaster X-FI highly modded 100 dB SNR , 0.0025% THD
 with OPA2211

 PPA v2 balanced input impedances, DC offset down to 6 mV with 
 ADA4627-1ARZ on ground channel 
 LT1028ACN on left and right

 headphones bright, accurate and transparent Sennheiser HD 438

 OK
 Some sound comes from source, some from PPAv2 op amps. Both influence sound about 50%. 

 Very hard to tell if there is any op amps in place. Compared to ADA4898-1YRDZ

 LT1028 is not as tight as ADA4898-1. Little soft but it might come from OPA2211 too. Everything is like covered in some sort of sticky stuff. Touch is a bit sloppy. Soundstage is neutral, not extremely wide but not too narrow either. Details are 100% there. Cannot hear any distortion. Echoes are pretty strong but short. 
 Now I want to only listen. Verdict, I don't like LT1028. Too natural and woody and sticky. 

 And these Phones Fatigue My EARS !! argh!


----------



## leeperry

hehe, I'm still not used to OPA211ID tbh..amazing X-Y-Z 3D SS, but much less "sweet" sound. I hope it'll get through, as LT1028AC was boring to death in movies in comparison...OPA211ID is as "out of the head" as it could possibly get, LT1028AC's SS was more "holographic" and euphonic, but also far more limited.


----------



## ROBSCIX

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_LT1028 is not as tight as ADA4898-1. Little soft but it might come from OPA2211 too. Everything is like covered in some sort of sticky stuff. Touch is a bit sloppy. Soundstage is neutral, not extremely wide but not too narrow either. Details are 100% there. Cannot hear any distortion. Echoes are pretty strong but short. 
 Now I want to only listen. Verdict, I don't like LT1028. Too natural and woody and sticky. 

 And these Phones Fatigue My EARS !! argh! 
	

	
	
		
		

		
		
	


	


_

 

I never thought he LT1028's were very good either...actually I have an entire array of Linear tech opamps and I only use them once in awhile.
 Some people are drawn to the "colored" type of opamps as it hide certain aspects of their gear, either source or cans.
 To each their own I guess.


----------



## Spacehead

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I never thought he LT1028's were very good either...actually I have an entire array of Linear tech opamps and I only use them once in awhile.
 Some people are drawn to the "colored" type of opamps as it hide certain aspects of their gear, either source or cans.
 To each their own I guess._

 

I tried lt1364 too and noticed that Linears have their own signature. It was different. Like technical, somehow colored. I guess they are better for high impedance headphones. LT1364 had very low dc offset btw. 

 I am very fond to Analog's op amps. I am now listening directly to AD8620 and it really shines, even to 32 ohm phones. Little distortion at high volumes but it is very soft rounded distortion that actually causes less listening fatigue than very low distortion! 

 I cannot listen National op amps. Burr Browns are ok, but too messy bass. Texas are too metallic.


----------



## joe_cool

Once you reach a high level of quality reproduction the synergy of components becomes important.


----------



## ROBSCIX

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_I tried lt1364 too and noticed that Linears have their own signature. It was different. Like technical, somehow colored. I guess they are better for high impedance headphones. LT1364 had very low dc offset btw. 

 I am very fond to Analog's op amps. I am now listening directly to AD8620 and it really shines, even to 32 ohm phones. Little distortion at high volumes but it is very soft rounded distortion that actually causes less listening fatigue than very low distortion! 

 I cannot listen National op amps. Burr Browns are ok, but too messy bass. Texas are too metallic._

 

Well circuit and playback gear are part of the equation. Linear tech doesn't really aim their products at the audio market. That is not to say that their opamps don't sound good to some. I didn't mind the LT1364 as a buffer in a DAC or the LT1057. There are others I like more of course but they are reasonable IMO. The AD8620, AD8599 are some good audio opamps and get high praise by those that have been rolling for a long time.


----------



## leeperry

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_I cannot listen National op amps. Burr Browns are ok, but too messy bass. Texas are too metallic._

 

yes, National opamps make my ears bleed 
	

	
	
		
		

		
			





 ah well, I can't stand OPA211ID anymore...it's got to go! majkel says he believe it plays the tones and harmonics separately...I dunno wth it does, but after trying really really hard, I cannot take it anymore. its strange SS simply cannot make it up for the rest.

 try 2*LT1363, this sounds really amazing! but it gets boring after a while...OTOH, I never seem to get bored of LT1028AC, but the more it goes the more I think that I cannot be happy w/ one single opamp...I used to love AD797B as DAC LPF + LT1028AC as buffer + NJM4580 to flood my phones...killer combo!


----------



## ROBSCIX

Quote:


  Originally Posted by *joe_cool* /img/forum/go_quote.gif 
_Once you reach a high level of quality reproduction the synergy of components becomes important._

 

Very true, some components just do not play well together.


----------



## Spacehead

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_ but the more it goes the more I think that I cannot be happy w/ one single opamp_

 

do you have an op amp keychain? 

 I could glue them together with epoxy and then drill a hole into it. I have about 5 specials that are burned or broken.... what a nice idea!


----------



## leeperry

yeah yeah yeah, back on 1028AC! this chip makes you feel good about life, who needs tubes? 
	

	
	
		
		

		
		
	


	




 vocals sound just as HD as can be, far more texture and body than OPA211? everything's so tight and entertaining 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_do you have an op amp keychain?_

 

the Prodigy HD2 soundcard allows you to roll 2 dual opamps for AK4396 LPF, one more dual for buffering and it's got a soldered NJM4580V on the HP out..so you can finetune combinations to get the best out of each of them, a roller's dream


----------



## buz

Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_do you have an op amp keychain? 

 I could glue them together with epoxy and then drill a hole into it. I have about 5 specials that are burned or broken.... what a nice idea! 
	

	
	
		
		

		
		
	


	


_

 

I used to have an epoxy encoated 486 die as keychain. Shame I lost it years ago... Would be nicer to take a few dies I guess


----------



## ROBSCIX

The older dimm module keychains seem to be all the rage for awhile.
 Still testing out some discrete opamps on the side here. Any of you guy been playing with an of those?


----------



## Spacehead

I don't have any experience on discrete op amps.

 Now I got AD8022 working on my portable partially SMD built CMOY that has a buffered ground channel. 

 R4 and R3 are 48K and 15K, R2 is 12K so input impedances are matched. 
 2.2 uF and 0.1 uF ceramics on power supply pins. 

 Supply voltage only 8.9V now. 

 AD8022 amazed me instantly. I thought that, Damn, this is pure music! There seems to be nothing extra and nothing is missing. I don't know as transparent op amp than this. There is very good output current capability for driving headphones directly. Distortion is very low. I have listened to AD8022 before on my X-FI and I am familiar with this bipolar op amp sound. It is very clean and reveals the sound of my headphones very well. I these Philips SHP 2500 phones are actually quite dark. 
 I think AD8022 would be the op amp if I needed to pick only one. 
 It has quite discrete sound. It requires good power supply decoupling or it starts to oscillate. And resistors need to be very close to op amp pins. Maybe this AD8022 is too bright? Highs start to fatigue me now a little. Or then I am listening so critically.

 I just got 6x1.2V AA batteries charged, so with them I can power this little amplifier for a very long time.


----------



## leeperry

Scott Wurcer posted several schematics for discrete opamps on diyaudio, he said you could make them for a couple of bucks


----------



## Spacehead

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_Scott Wurcer posted several schematics for discrete opamps on diyaudio, he said you could make them for a couple of bucks 
	

	
	
		
		

		
		
	


	


_

 

I think IC op amp cannot be beaten by a discrete one. It is just physics. 

 But of course, My Own DISCRETE op amp would sound so awesome, I think! 
	

	
	
		
		

		
		
	


	




 AD8022 needs some smooth op amps to ground channel and to source so that it doesn't sound fatiguing. Now I need to change OPA1642 for something else. 
 I wonder if I could get OPA2613 working too, it has insanely high current output and sounds fine, while working on very low voltages. 

 I posted pictures of this mini smd cmoy to post your builds thread. oh, I need to picture the underside too.


----------



## leeperry

well, the discrete advocates like to remind us that an IC opamp is a big as a grain of rice, and is just a nasty compromise towards SQ...this is parly true, but thankfully you can find expensive and fantastic sounding IC's like AD797B/LT1028A etc...they really don't have anything to envy to good discretes IMHO.

 OTOH, a $0.1 5532 sounds like ****..it just does 
	

	
	
		
		

		
		
	


	




 and the IC advocates like to remind us that all the components and soldering points you see on those discrete opamps *are* in your audio path...and ideally you'd want your audio path to be as short as possible, duh!

 but some ppl like tubes, and their distortion is up through the roof 
	

	
	
		
		

		
		
	


	




 so different strokes for different ppl I guess...and due to the new toy syndrome, what you are thinking today might/could/will change (completely? 
	

	
	
		
		

		
		
	


	




) after a few days/weeks/months.

 I've listened to all the discrete opamps from A-GD/Burson, and to most of the top range IC's from TI/LME/AD/LT....LT1363 was great for a few days, because it can give you the feeling to be in the studio cabin right before the singer, but it's VERY colored...there's no "perfect" opamp anyway, you need to find the one w/ the less drawbacks to your ears 
	

	
	
		
		

		
		
	


	




 I've been told great stuff about AD845KN, and I see that a bunch of expensive DAC's are using it: Harmony Design DA9 - DAC [English]
  Quote:


 audiophile-class AD845 opamp 
 

my usual chinese seller can provide me w/ two of them for dirt cheap...I'll keep it in mind! Andrea loooves it, majkel says it's terrible


----------



## Spacehead

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_well, the discrete advocates like to remind us that an IC opamp is a big as a grain of rice, and is just a nasty compromise towards SQ...
 and the IC advocates like to remind us that all the components and soldering points you see on those discrete opamps *are* in your audio path...and ideally you'd want your audio path to be as short as possible, duh!
_

 

I didn't think about the fact that actually op amps aren't designed for audio only. That is the fun of this, searching for the ultimate op amp 
	

	
	
		
		

		
		
	


	




 Do you ever think how your music goes through some dirty solder joints and possibly long thin wires and gets ruined this way? It is just ugly. 

 OK, I plugged that OPA2613 to that smd cmoy and set voltage to +12V on LM7805 regulator. 

 OPA2613 sounds quite similar to OPA637. Not as delicate but smoother than AD8022 for example. I think about 50 mA current output is enough for 32 ohm headphones because I cannot hear any difference in distortion or bass when compared OPA2613 (350 mA) and AD8022 (50 mA). 
 Maybe I should remove the output resistors, I have 10 ohm there. But they are for op amp stability. Some say that output impedance should be very low for good sound. OPA2613 would have 0.01 ohm output impedance but my output resistor ruins that.


----------



## pulsar08

Can I use my opa627 and ad8610 on adapters and ad823 which I bought for my pimeta v2 safely in my little dot I+? I read somewhere that fet input opamps are more fragile so I don't want to kill them. I've tried lt1364, lme49860, opa227, ad8599, and opa2132 I would have to say I prefer the opa2132 the best so I was thinking the opa627 would probably be amazing.


----------



## joe_cool

Quote:


  Originally Posted by *pulsar08* /img/forum/go_quote.gif 
_Can I use my opa627 and ad8610 on adapters and ad823 which I bought for my pimeta v2 safely in my little dot I+? I read somewhere that fet input opamps are more fragile so I don't want to kill them. I've tried lt1364, lme49860, opa227, ad8599, and opa2132 I would have to say I prefer the opa2132 the best so I was thinking the opa627 would probably be amazing._

 

I thought the OPA627 was clean but boring, OPA134 was honkey, and OPA604 was OK. AD8610 and AD825 I like better. LME49710 is best in most cases.


----------



## Spacehead

Quote:


  Originally Posted by *pulsar08* /img/forum/go_quote.gif 
_Can I use my opa627 and ad8610 on adapters and ad823 which I bought for my pimeta v2 safely in my little dot I+? I read somewhere that fet input opamps are more fragile so I don't want to kill them. I've tried lt1364, lme49860, opa227, ad8599, and opa2132 I would have to say I prefer the opa2132 the best so I was thinking the opa627 would probably be amazing._

 

I change so much op amps that they get broken pretty soon. I guess op amp fails when it puts out full rail voltage to another channel. nothing can be done then?

 If that amplifier is optimized for jfet op amps, then you can change them freely I think. 

 Did you check dc offset when you tried LME49860 and AD8599. They are bipolar op amps and don't work too well on jfet optimized amplifier. 

 What headphones you have? OPA2132 can be fine if the bass doesn't get messy, headphones should be very bright?


----------



## leeperry

BTW, is there a single version of 4580? I'd like to try that if it even exists.
  Quote:


  Originally Posted by *Spacehead* /img/forum/go_quote.gif 
_Do you ever think how your music goes through some dirty solder joints and possibly long thin wires and gets ruined this way? It is just ugly._

 

indeed, but we still got plenty of "headroom" distortion-wise IMO...listen to those 49720/49990 opamps, uber-low THD = ear-splitting bright trebles and bass shy to the utmost..

LME49990 Audio Op-Amp - better than AD797? - diyAudio
  Quote:


 lower distortion does not always equate to better sound. 
 

the other day I went to an audio repair shop, and the guy had built his own preamp/amp, there was *ONE* single transistor in his amp...fed from a toroidal PSU w/ a whole bunch of huge caps to stabilize it. He was clearly an advocate of the minimalist approach...show him a dual discrete opamp and he'd have a seizure for sure


----------



## pulsar08

The dc offset with lme49860 was ~0-1 both channels, ad8599 was ~1/3, lt1364 was 36mV but I figured that was safe with only 32ohm impedance. I gave ad8610 a quick listen and it was pretty bad. opa627 otoh is by far the best. nothing else I've used is anywhere close. This is with a modded x-fi using lme49860 as source and ms1i's. The little dot tubes are Amperex 6ak5w 5654 made in GT. Britain.


----------



## weibby

I can't seem to find it anywhere.

 wanna roll my opamp on the mini3 for testing purposes..do you guys know where i can get a DIP to SMD socket?


----------



## Spacehead

Quote:


  Originally Posted by *weibby* /img/forum/go_quote.gif 
_I can't seem to find it anywhere.

 wanna roll my opamp on the mini3 for testing purposes..do you guys know where i can get a DIP to SMD socket?_

 

Sijosae knows:






 I think for reliability that socket needs to be glued to the pads so it can withstand the pulling and pressing forces. 

 I have made my own dip to smd adapter but it is ugly and has too long wires. I should have made that sijosae socket. I used epoxy for gluing. 

 There is something:
DIP to SOIC IC Adapters from ePBoard Design to convert SOIC, SSOP, TSSOP, VSOP, MLP, PLCC, CLCC, QFN, SOT, SC, TVSOP, TQFP, LQFP, PQFP, VQFP, TSOPI, TSOPII.
 But it is 10 dollars.


----------



## leeperry

Quote:


  Originally Posted by *weibby* /img/forum/go_quote.gif 
_a DIP to SMD socket?_

 

Browndog DIP8 to SO8 Adapter


----------



## K3cT

My op-amp rolling days are over as I plan to build the discrete β22 next but throughout my experience so far, I say just get yourself a piece of ADA4627-1 and be done with it. These are the most well-balanced sounding op-amps among everything I've ever heard. Runner ups are AD8597 and AD797BRZ.


----------



## weibby

Thanks guys!


----------



## buz

How much better than the AD797BR would the ADA4627 be? That one is seriously expensive and does not look to be available in DIP at all...


----------



## Mad Max

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_How much better than the AD797BR would the ADA4627 be? That one is seriously expensive and does not look to be available in DIP at all..._

 

4627-1BR is more balanced and neutral than 797BR with better, more extended treble. Give it a try sometime! =]


  Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_My op-amp rolling days are over as I plan to build the discrete β22 next but throughout my experience so far, I say just get yourself a piece of ADA4627-1 and be done with it. These are the most well-balanced sounding op-amps among everything I've ever heard. Runner ups are AD8597 and AD797BRZ._

 

Add 8091 and metal can 744 to that list.


----------



## buz

Mhh farnell wants 45USD for the 4627 in Switzerland. And then it's not even DIP 
	

	
	
		
		

		
		
	


	




. I think I'll pass for now.


----------



## 12Bass

Interesting comments regarding the ADA4627-1.... Didn't find the ADA4898-1 to be that impressive. Although I don't usually like to generalize, it seems that FET op amps are often not as transparent/uncolored as the better bipolars. Perhaps the ADA4627-1 bucks that trend?


----------



## Mad Max

Quote:


  Originally Posted by *12Bass* /img/forum/go_quote.gif 
_Interesting comments regarding the ADA4627-1.... Didn't find the ADA4898-1 to be that impressive. Although I don't usually like to generalize, it seems that FET op amps are often not as transparent/uncolored as the better bipolars. Perhaps the ADA4627-1 bucks that trend?_


----------



## leeperry

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_just get yourself a piece of ADA4627-1 and be done with it._

 

A or B? any audible diff?

 tried LT1028AC?


----------



## K3cT

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_A or B? any audible diff?

 tried LT1028AC?_

 

I've never tried the A version but MadMax did. He can comment on that. 
	

	
	
		
		

		
			





 Hmm... I'm not sure about the AC grade but I did try the ACN8. The 4627-1 is way more neutral, extended and detailed in comparison.


----------



## SpudHarris

K3cT - I'm also back with the 4627-1, I never gave them a proper audition when they originally arrived because I was proper rollin' mad at the time. I have given them some time the last few days and am falling big style.......


----------



## Mad Max

Quote:


  Originally Posted by *K3cT* /img/forum/go_quote.gif 
_I've never tried the A version but MadMax did. He can comment on that. 
	

	
	
		
		

		
		
	


	




 Hmm... I'm not sure about the AC grade but I did try the ACN8. The 4627-1 is way more neutral, extended and detailed in comparison._


----------



## leeperry

I don't speak chinese pork Madmax, care to elaborate? 
	

	
	
		
		

		
		
	


	




 ok, I'm really interested in AD845KN anyway, it seems to be the same family as AD797 and "K" is the highest grade: http://www.analog.com/static/importe...eets/AD768.pdf
  Quote:


 op amps such as the AD845 or AD797 may be more appropriate 
 

Top opamps, did I miss any one? Yes AD797 
  Quote:


 Never fond of AD797, but also try AD845, LT1028, and AD811/LM6181. 
 The AD845 is almost class A 
 

but majkel doesn't make it too appealing: AD797 now sounds like it should - Page 2 - Head-Fi

 also curious about AD8597, still


----------



## ROBSCIX

Quote:


  Originally Posted by *joe_cool* /img/forum/go_quote.gif 
_I thought the OPA627 was clean but boring, OPA134 was honkey, and OPA604 was OK. AD8610 and AD825 I like better. LME49710 is best in most cases._

 

I agree, the LME49710HA is a great sounding units. I built units for quite a few associates and every time I received excellent feedback.
 I tend to use the HA version of this opamp though.


----------



## leeperry

I've decided to give a second chance to LT1363CS8, yummy! 



 SS is very wide, vocals sound very true to life and bass is even more percussive than on 1028AC 
	

	
	
		
		

		
		
	


	




 no wonder there's a stock 1364 in this one: Super Pro DAC707

 I'm also expecting some AD845KN and 4627-1A.


----------



## buz

Did you also try the LT1364? A dual would sure be easier to deal with but most people seem to think they sound worse...


----------



## leeperry

I already compared 1363/1364, 1363 was much clearer indeed.

 so far I'm very impressed, it takes everything I liked from 1028A and adds even more percussive low end bass and a much wider SS, together w/ what it does best: true to life vocals. it's an all time fav from LT to many ppl for a reason 
	

	
	
		
		

		
		
	


	




 and it can output 50mA so it drives my 32Ω phone dead easy...DC offset is around 5mV.

 it's also Unity Gain Stable, Firestone recommended me to use that if any possible.


----------



## Mad Max

I enjoyed 1363 most with DT880 when I had it.
 I haven't really used at all in a long time.


----------



## leeperry

it's almost as you can hear its very high speed, it can snatch tiny minute details...I feel that 1028A used to be a bottleneck to my phone, now they're the bottleneck...not the opamps anymore


----------



## Spacehead

damn! I got Koss KSC75 today. And only single op amps in the chain now! 
 LT1028ACN on X-FI and ADA4627-1ARZ x 2 + ADA4627-1BRZ x 1 on PPAv2

 So lovely sound coming from my system. I don't know if this is hifi but it is very rocking fluent. KSC75 seem to benefit from the massive power reserve of PPAv2 much better than Sennheiser HD 438. And there is no hiss.

 These op amps of course are absolutely most best op amps I know. And I know you think the same. Perfect!


----------



## leeperry

what kind of diff to your ears between ADA4627-1ARZ/BRZ?


----------



## Spacehead

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_what kind of diff to your ears between ADA4627-1ARZ/BRZ?_

 

I have not tried yet. How could I recognize the sound, It should be extremely subtle difference? The source mixes things up. I could try to establish some kind of base sound from LT1028 on the X-FI and 
 then
 ADA4627-1BRZ on left and right , ADA4627-1ARZ on ground 
 and other way around. 

 Need to solder one BRZ...

 Which headphones should I use, KSC75 or HD 438 ?


----------



## Mad Max

Hmm, I've spent the last few days giving 4857-1 a more thorough listen, and now I swap out to 8091, and dang, I really didn't give this one a good chance. It's less forgiving, smoother, and more extended with better bass presence. 
	

	
	
		
		

		
		
	


	



 I'm realizing how much micro-detail I've been missing from 4857-1.

 Not entirely sure how 4627-1B sounds in your equipment, but the AR should at least be warmer.

 They sound almost the same in my gear, just the A is lukewarm with slightly less treble extension than B. B is neither warm nor cold.


----------



## buz

What is the best place to get single to dual opamp adapters? Any other place than cimarron with potentially lower prices?


----------



## Mad Max

eBay

 Won't be that much cheaper if at all. I don't know of any other sources.


----------



## ROBSCIX

Quote:


  Originally Posted by *buz* /img/forum/go_quote.gif 
_What is the best place to get single to dual opamp adapters? Any other place than cimarron with potentially lower prices?_

 

Adapters for surface mount or DIP8 opamps?

 You mean an adapter that takes two single channel units and adapts them to a dual DIP8?


----------



## buz

Exactly using two single DIP8 opamps to convert it to dual DIP8, not surface mounts


----------



## leeperry

still very impressed by 2*LT1363CS8 here...its low end bass control and SS clarity are just amazing, sky is the limit o/

 Samuel Groner said that it runs its input stage in class AB.


----------



## buz

Would there be any appreciable difference between the CS (SMD) and CN (DIP) version of the LT1363?


----------



## leeperry

FWIW I didn't like CN...CS gives a shorter signal path, and this is a very high speed opamp.


----------



## Mad Max

So the soic version is better? Or more "ideal?"
  What differences did you hear?


----------



## buz

Would these http://cgi.ebay.ch/2x-Dual-to-Mono-Opamp-PCB-OPA2604-NE5532-LM358-OPA627-/360249045976?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item53e08433d8 be decent or am I better off just getting the real  browndogs with sockets?


----------



## Spacehead

I guess those are fine. But really expensive. 
  
  Quote: 





buz said:


> Would these http://cgi.ebay.ch/2x-Dual-to-Mono-Opamp-PCB-OPA2604-NE5532-LM358-OPA627-/360249045976?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item53e08433d8 be decent or am I better off just getting the real  browndogs with sockets?


----------



## buz

Expensive? Cimarron charges 9$ per piece...


----------



## Spacehead

Do your own, 2 $ per piece with 0.50$ sockets.


----------



## buz

And 30 bucks for soldering equipment plus time which is always in short supply


----------



## Spacehead

And it would be prettier
   
   
  BTW I got BUF634T today! 
   
  installed them straight away . Sounds like OPA2132 even when I have AD8599 on front and left. Though OPA2132 on ground with OPA633. So quite a BB amplifier now running.


----------



## leeperry

Quote:


mad max said:


> So the soic version is better? Or more "ideal?"
> What differences did you hear?


 

 better clarity?
   
  if you're on the cheap, you can use those: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230408616394
   
  I've just ordered ten of them, and I've got 4 of  the same opamps for several chips...so it'll make for a nice shootout against the browndogs


----------



## buz

Damn, I should really learn to solder


----------



## headphoned

Personally, I have an informal list of favorites that looks like this: AD797ANZ, OPA1611, AD845, OPA132UA, OPA827, EL2228, EL2227 (G >= +2), LME49725, LME49723, TL051/052, LME49880, THS4051/4052, LT1363.


----------



## SpudHarris

Is that list in order of preference?


----------



## headphoned

Not exactly, but at least AD797 and OPA1611 are the opamps I would keep if I could only keep 2 types with me and I should have to let everything else burn in hell, lol


----------



## headphoned

oops, double post


----------



## Mad Max

Quote: 





leeperry said:


> Quote:
> 
> better clarity?
> 
> ...


 
  I have the single soic to dip ones, very sturdy and make good contact, easy to work with, just take care not to short the soic leads with pins 2 & 3 and 6 & 7.


  
  Quote: 





buz said:


> Would these http://cgi.ebay.ch/2x-Dual-to-Mono-Opamp-PCB-OPA2604-NE5532-LM358-OPA627-/360249045976?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item53e08433d8 be decent or am I better off just getting the real  browndogs with sockets?


 
  I have those, they are also very sturdy and make good contact - you can't go wrong with those, I believe.


----------



## leeperry

Quote: 





mad max said:


> I have the single soic to dip ones, very sturdy and make good contact, easy to work with, just take care not to short the soic leads with pins 2 & 3 and 6 & 7.


 
  whaddayamean? I will solder the golden pins before the chips to avoid overheating, but then it's gonna be a major PITA to solder the bottom chip, d'oh!

 OTOH, the browndogs don't have soldered pins, so the contact sure will be better. I've got a bunch of LT1363CS8, so they'll be the first to run the shootout for sure 
	

	
	
		
		

		
		
	


	



   
  also, the ebay browndogs have 2oz copper traces, so it might very well all add up in the end


----------



## Mad Max

Quote: 





leeperry said:


> whaddayamean? I will solder the golden pins before the chips to avoid overheating, but then it's gonna be a major PITA to solder the bottom chip, d'oh!
> 
> OTOH, the browndogs don't have soldered pins, so the contact sure will be better. I've got a bunch of LT1363CS8, so they'll be the first to run the shootout for sure
> 
> ...


 
  Oh right, I forgot you're going to use the 2x soic to dip, right? I was talking about the single soic to dip, d'oh!
  Forget what I said, lol.
   
  Now I have to try the soic LT1363 =)
 I desoldered the failed 4898-1 chips so I have a spare pair of adapters. :atsmile:
   
  Edit: I've been spending time with 1363CN8, I'm liking the micro-detailed presentation with forward vocals, but switching back to 4627-1, it does vocals much better than 1363, lol.
  Now I'm spending time with 4841-1 once more. I had forgotten how this one has the best stereo separation in my collection. Very good detail.


----------



## leeperry

better vocals? that's what 1363/1364 are famous for tbh...together w/ their tight low end bass response.
   
  4627-1B does bass just as accurately, and SS as well?
   
  when you ask LT about the best chips for audio they answer:
   
_"Audio is not an application that we have focused on, but our parts are often selected for high-end systems. Some good parts to consider include:_
_LT1468 (low distortion, low current noise, low voltage noise)
 LT1678
 LT1364
 LT6231 (for lower supply voltage apps)_
   
_Of the parts listed below, the 1364 is available in DIP-8 so maybe that's your best choice. One of our guys who plays with this part in the lab reported that he saw distortion performance that was even better than is suggested by the graphs in the data sheet. He said it was low to the point that he had trouble measuring it."_
   
  I have to admit that I'm catching soooo many small details w/ 1363CS8, the low end bass is very tight and lean and the SS as clear as can be...very cool stuff! and blues harmonica sounded good on 1028A, but on 1363 it's


----------



## Mad Max

Comrade, 4627-1 does _everything_ better. However, 1363 brings vocals forward, whereas 4627-1 just refines and cleans them up. Doesn't push them forward nor back.
  And then better clarity from 4627-1.
  4627-1's bass has better low-end punch and tighter. SS is slightly wider, too.


----------



## leeperry

yes, many ppl say that 1363/4 give them the feeling to be in the studio cabin w/ the singer before their eyes...I would definitely agree on this, and it's also fantastic for movies dialogs clarity!
   
  also, 1363 has a PSRR of 100dB, so it needs a clean PSU...but its 1000V/us very high speed is quite something.
   
  ok ok, I need locate some 4627-1B then(yay, $18 a pop 
	

	
	
		
		

		
		
	


	




)


----------



## headphoned

I have yet to meet with an opamp that does "everything better than" another. For instance, take the AD797: it has this great precision, but it's too "descriptive", it sort of lacks passion. My CD player with the NE5532 sounds better, has more passion. So did my DAC when it had the AD845, which may be slightly lower resolution than the AD797, but eventually just sounded better to me. I need to try the NJM2114, an opamp with only 40 dB of open-loop gain, meaning that at unity gain it has a lot of dB's less feedback than most opamps, which should make for better sound  In a 24V CMOY (with balanced input impedances) the NJM sounded promising: snappy sound with clear transients, and lifelike tonality (unlike that "dead" OPA2604 for instance). A bit incoherent though (there, at least), with slightly recessed midbass and slightly forward lower treble.


----------



## headphoned

Or I'll switch to LME49725 or EL2228 which are highly musical opamps, the former more warm, the latter more resolving.
   
   
  For me even an OP275 is competitive to the AD797, since it has the passion (musicality, beauty, interest, however you like to call it) even though it trades it with ultimate insight.
   
  Something like an LT1363 is a good choice for a highly musical sound, as well.
   
   
  The OPA1611 though might be the best combination of precision and musicality I've stumbled on so far. It's a cool chip.
   
   
  P.S. Firstly though (before trying other stuff) I'll try to simply change interconnect from Oehlbach MP3! (very precise) to Chord iChord (very beautiful but still quite precise), leaving the AD797 inside my NG98 (with OPA132UA in the headamp side).


----------



## headphoned

Finally, another opamp that I found to beautifully conjugate transparency and musicality was the THS4051; so much so that in case I decide to remove AD797 & OPA132UA I will replace them with THS4051 & OPA827 respectively.


----------



## headphoned

Finally, another opamp that I found to beautifully conjugate transparency and musicality was the THS4051; so much so that in case I decide to remove AD797 & OPA132UA I will replace them with THS4051 & OPA827 respectively. 
	

	
	
		
		

		
		
	


	



   
  And that JRC Muses 02.... mmm, it makes me dream of a sweet tropical paradise...


----------



## Apocalypsee

Haven't posted here for a while. Just bought X-Fi Surround 5.1 USB for lapto with modded HD-437. Stock sound quality are pretty good, but I changed to my favorite LME49723 and it transform it to something else. Sounds way better, less bloated bass, airy and better soundstage and better mids that integrate well with the low and high. I wanted to change to LT1364 but I don't have it in SOIC, but I loved it anyway


----------



## headphoned

Glad that you like the LME49723 
	

	
	
		
		

		
			




   
  I think it's better than the LT1364.
   
   
  I'd wanna try the LME49725 again, after the AD797.


----------



## headphoned

Quote: 





mad max said:


> Comrade, 4627-1 does _everything_ better. However, 1363 brings vocals forward, whereas 4627-1 just refines and cleans them up. Doesn't push them forward nor back.
> And then better clarity from 4627-1.
> 4627-1's bass has better low-end punch and tighter. SS is slightly wider, too.


 
  It doesn't take much to have better clarity than the LT1363, actually. The LME49720HA manages to have far more clarity too, like the OPA1611 and the AD797. The LT1363 is a "forgiving" opamp and that, together with its luminous sonic character, is what makes it charming.
   
  There's a more detailed and analytical opamp from the LT, which gives up the magic of the LT1363/1364's luminosity for more insight: it's the very much overlooked *LT468*/*1469*.
   
  I'm thinking that I may try two LT1468 to compare them to the AD797 and see which has more clarity.


----------



## buz

Is there any place to get 4267 in DIP (single or dual) config? How about AD797BNZ (ANZ is available, B only in SOIC)


----------



## headphoned

There is no reason in the world to spend more for BRZ for audio. Check the datasheet for yourself 
   
  The ADA4627 does not exist as DIP. Instead I'd suggest that you try 2x OPA827 - maybe get the pre-mounted adapter from Browndog ($49 though). The OPA827 sounds quite good with the CS4398.


----------



## buz

49USD? More like 9. Or less than that on ebay... OPA827 is quite cheap, I may indeed try that one. And a bunch of LT1363 while I am at it


----------



## headphoned

On an absolute level of judgment, the OPA827 has to be much preferable to the LT1363, since it's much clearer (the LT1028 is closer), with better bass too.
   
  Yuck, the Browndog with two pre-mounted OPA827 costs $49 actually. But this can be a definitive opamp, so it's not money thrown away.


----------



## Spacehead

I installed ADA4627-1BRZ x 2 on my Sound Blaster X-FI. It seems that soundstage improved a little compared to LT1028ACN. I am listening through mini3 clone, with AD8620 on ground and AD8397 in left and right with HA-5002x2 buffers on ground


----------



## buz

Why bother getting it premounted if you can get adapters plus the chips for less than half the price


----------



## headphoned

Because then you must solder


----------



## headphoned

Quote: 





spacehead said:


> I installed ADA4627-1BRZ x 2 on my Sound Blaster X-FI. It seems that soundstage improved a little compared to LT1028ACN. I am listening through mini3 clone, with AD8620 on ground and AD8397 in left and right with HA-5002x2 buffers on ground


 

 How about musicality, compared to the LT1028ACN (which I know well) ? I'm kind of sceptical on the ADA4627-1 regarding musicality, I don't know...just my 6th sense


----------



## Spacehead

Quote: 





headphoned said:


> How about musicality, compared to the LT1028ACN (which I know well) ? I'm kind of sceptical on the ADA4627-1 regarding musicality, I don't know...just my 6th sense


 

 Little smoother, LT1028ACN is tighter. Cymbals have decay and other details are intact. I have a feeling that ADA4627-1 is slightly more musical.
   
  AD8022 is most musical op amp I have heard, but it lacks bass.
   
  BTW. I am listening now through Koss KSC75. Are they detailed enough for op amp comparison? I am waiting for Sony MDR-V6, they should have enough accuracy for good comparison ability?


----------



## headphoned

Those headphones, well, I don't really know...
   
  Anyhow I did use the AD8022. It was nice, as I remember. I didn't feel it was perfect nor extremely musical, though. I prefer the EL2228. I do think that the LME49725 is more musical than both 
   
   
   
  Why is there no interest for that new LME49990, nor for the dual FET-input LME49880? So far I've used the latter and really liked it, I guess it's my favorite dual FET chip.


----------



## T.B.N.

I just finished a CMOY with a OPA132 and I'm using 9V. It sounds weak and light on bass. I have a gain of 3 as of now. Would it sound better if I gave it 18V? I also have a OPA227, maybe that would sound better with only 9V?
   
  Would the CMOY generally be better with 18V?


----------



## Spacehead

Quote: 





t.b.n. said:


> I just finished a CMOY with a OPA132 and I'm using 9V. It sounds weak and light on bass. I have a gain of 3 as of now. Would it sound better if I gave it 18V? I also have a OPA227, maybe that would sound better with only 9V?
> 
> Would the CMOY generally be better with 18V?


 

 It will be weak without proper ground channel. OPA132 cannot drive low impedance headphones properly. What headphones you have?


----------



## headphoned

Quote: 





t.b.n. said:


> I just finished a CMOY with a OPA132 and I'm using 9V. It sounds weak and light on bass. I have a gain of 3 as of now. Would it sound better if I gave it 18V? I also have a OPA227, maybe that would sound better with only 9V?
> 
> Would the CMOY generally be better with 18V?


 
  I have used the OPA132UA and it was more than ok in my 24V CMOY, with my Senn. HD238, but admittedly it's not the most full sounding since it doesn't have the most output current. If you really want full sounding, try these: OPA551 (with more than 12V), TL052, TLE2062 (good for 9V), TLE2082. Also the OP275 drives headphones well with 24V of supply voltage, it was one of my favorites.
   
  P.S. Currently I'm using two TL051 @ 24V


----------



## Spacehead

OPA2613 is very strong op amp and is easy to stabilize with resistors very close to op amp pins (cmoy has them this way) and proper decoupling capacitors on both power pins.
   
  It is Burr Brown op amp and sounds good!
   
http://focus.ti.com/docs/prod/folders/print/opa2613.html
   
  350 mA output current


----------



## headphoned

Yep, but being a high- input bias current opamp, it's excluded that it would be usable in a CMOY, even one with balanced input impedances like mine 
   
  The THS4051/4052 would be more usable, perhaps, but still too much Ib.
   
   
  The great thing about OPA551 (200 mA output current), TL051/052 (40 mA or more output current), TLE2062 (80 mA output current), TLE2082, is that they're all FET and will work in any CMOY.
   
   
  The TLE2062 is the most straightforward choice I know of... perfect even for 9V, a lot of output current and it hears, no DC offset issues, sounds really good...
   
  But me personally, I'm enjoying these TL051's a lot. Tubey sounding and emotional, without any lack of detail. I even really appreciated the TL052 in a +/-12V line-level application, compared to OPA1642 and LME49880.


----------



## Spacehead

I got OPA2613 working smoothly on my input balanced cmoy. But the resistor are smd and soldered to op amp pins. feedback loop is as short as resistor. I like AD8397 and OPA2613 is quite good too.
   
  I don't have any OPA551 , but OPA552 , it is very laid back sounding on PPA v2. 
   
  But TLE2062 is slow op amp, how can it sound good!? And distortion is 0.025% That is high. But human ears cannot hear under 0.1% THD?
   
  I prefer bipolar op amps. They sound more musical.


----------



## headphoned

Any opamp with lower output current than its 80 mA will distort more than 0.025% on 32 ohm headphones anyway  And it's slow, but not too much. Slow actually is a good thing in CMOY opamps, since it makes them less likely to ring = sound hard with capacitive loads such as headphones. Just try it I guess 
   
   
  The OPA552 is uncompensated, usable only with gains higher than 5. Otherwise it has the same potential as the OPA551 in a CMOY. The reason why it sounded so laidback in the PPA, must be that it's an opamp that's provided with an internal 200 mA buffer, and this certainly gives it a lot more drive than the typical opamps, but it's equally sure that it makes the PPA's discrete output stage redundant. In other words... not a good idea to use that one in a buffered headphone amp. Much better for a CMOY, the OPA551 when gain is lower than 5, the OPA552 with higher gain. Nevertheless, based on sound alone I'd probably prefer the more open-sounding TL051 to the OPA551 in my gain-of-4 CMOY, driving my easy-to-drive HD238.


----------



## headphoned

I generally prefer bipolars as well, i.e. the OPA1611 to the OPA1641, the LME49725 to the LME49880, and so on.
   
  But a CMOY is a different story


----------



## leeperry

quoting on this forum is a pain..anyway:
   
_"Any opamp with lower output current than its 80 mA will distort more than 0.025% on 32 ohm headphones"_
   
  JRC4580 is universally used to drive phones and it's got a max output current of 50 mA...care to explain please?


----------



## Spacehead

There is good amount of details
   
  I have ADA4627-1BRZ (x2) on X-FI
   
  ADA4627-1ARZ (x2) on PPAV2 with LT1364 on ground
   
  Soundstage is wider than I am used to. Presentation is very smooth. I can tell easily that lower bitrate music has lots of artifacts. Only FLACs sound very nice.
   
  I cannot actually hear the op amps. It is so transparent, I hear the DAC, CS4382


----------



## headphoned

Quote: 





leeperry said:


> quoting on this forum is a pain..anyway:
> 
> _"Any opamp with lower output current than its 80 mA will distort more than 0.025% on 32 ohm headphones"_
> 
> JRC4580 is universally used to drive phones and it's got a max output current of 50 mA...care to explain please?


 
   
  Universally? Well, maybe in sound cards. That does not mean it's the perfect buffer, LOL. Two BUF634 would distort much less, although I haven't been making measurements. I just know it


----------



## headphoned

_"JRC4580 is universally used to drive phones and it's got a max output current of 50 mA...care to explain please?"_
   
  That it's often used in soundcards certainly does not mean it's the perfect headphone driver  it's just cheap and effective I guess.
   
  On the other hand, even a 200 mA buffer like the Intersil HA-5002 was found to distort significantly with a 32ohm load, as I recall. There was a thread on this sort of things long ago in this forum. The BUF634 kept distortion low even with 32 ohm, anyway.


----------



## headphoned

_"There is good amount of details_
   
_I have ADA4627-1BRZ (x2) on X-FI_
   
_ADA4627-1ARZ (x2) on PPAV2 with LT1364 on ground_
   
_Soundstage is wider than I am used to. Presentation is very smooth. I can tell easily that lower bitrate music has lots of artifacts. Only FLACs sound very nice._
   
_I cannot actually hear the op amps. It is so transparent, I hear the DAC, CS4382"_
   
   
   
  Personally, I never like to use the same opamp twice in a signal path. Sound will never be neutral and satisfying in the long term (for my ears).


----------



## headphoned

In a moment I'm going to replace the AD797, which after all stays too dull for my liking (and no sin is worse in audio). I guess I'll put in one of my LT1028ACN8 adapters, or a NJM2114, or LME49725... and probably the AD845KN in the amp side (of my NG98).


----------



## buz

I am idiot. The OPA827 does not actually come in DIP - shouldn't have drunk that much beer at end of week drinks...


----------



## headphoned

Not a big deal 
   
  Even I was tempted (due to infinite laziness) to buy that 2x OPA827 $49 Browndog.


----------



## sachu

The AD797 is dull??!
	

	
	
		
		

		
			




   
  Save your breath with the LME chip. It didn't sound refined at all to me. It did add some weight to the overall response but  was rough all around too. I was using them both in a Sallen Key filter role on the output of my DAC.


----------



## buz

It's really a rip off though. Those chips go for like 8bucks. I should find a local EE student to solder stuff for me


----------



## headphoned

Yes, dull. Compare with a simple OP275. The AD797 sounds dull in comparison. I just want a bit more tonal richness (which an otherwise rigorous chip like the LT1028ACN8 should give me - since I don't have adapters at hand to solder the OPA1611 to, although I'm expecting them).
   
   
  Regarding the LME49725, I've used it at 12V and 24V. It sounds better with 24V, while with 12V it's a bit edgy in the treble. I found its midrange response to be mellower (@ 24V in a Super Pro DAC) than that of the OPA827.
   
  EDIT: Actually inside a Xenos headphone amp, powered with +/- 12.5V, the LME49725 was a bit rough indeed. Funnily though, not at all so in the Super Pro at about the same voltage. The LME49723 was nicer sounding inside the Xenos.


----------



## buz

Does the OPA827 have more bass slam than the LT1028C? I must really be a bass head, I seriously messed around with +6db bass on for my D2000


----------



## headphoned

Hmm, I don't know, it surely doesn't lack it though. Maybe for bass slam the best solution would be a LM4562HA or LME49720HA on proper Browndog adapter (TO99 to DIP). That one has big bass (coupled with ever-so-slightly thin mids, though).
   
   
  BTW, regarding the AD797, I need to think more. Well... listen more  Probably I'll replace the interconnect with the harmonically rich Chord iChord for first.


----------



## buz

Thin mid is not necessarily what you want with a D2000


----------



## headphoned

I have no idea 
	

	
	
		
		

		
		
	


	



   
  Anyhow, it's absolutely worth it to try the LM4562HA. (I would tend to suggest this over the LME49720HA, which is what I have myself since you can have them as free samples unlike the former


----------



## buz

Mhh the the 4526HA is really pricy, at that price I could get the browndogified OPA827


----------



## headphoned

Why do you assume that the OPA827 would be better? Just because the LM4562HA is dual? I don't think so. At any rate, both will pair well with the CS4398 DAC, no problem then 
   
   
  Myself, I have changed neither AD797 nor Oehlbach interconnect, LOL, I just changed CD 
   
  Yes, no, LOL, the AD797 is not dull. Certainly the AD845KN was somewhat more colorful, at the risk of being slightly colored. But the AD797 at least at 12V reaches a further level of insight, remaining enirely smooth & fluid, so what more do I want?  I might try a 24V power supply instead. I have a TREAD kit on order, and I have finally acquired the NG98's stock 24V power supply too (they cheated on that).


----------



## headphoned

I have changed the mini->mini interconnect from my PCDP to my 24V CMOY instead. Now those TL051's are so awesome that I almost believe that the CMOY is sounding better than the built-in buffered amp of my NG98, LOL. At least with the HD238 that's easy to drive, both amps are fine and I couldn't say that one is superior. Both give a lot of oomph to the bass when required, and remove that slight trace of dryness the HD238 has in the midrange (I'd say the TL051 is especially good at this). That TL051 is a real jolly of an opamp, and not just for CMOYs. I might also make a new Browndog with two of them and try and replace the OPA132UA's with them in my NG98, driving the BUF634's.


----------



## buz

So which opamp do you have after the DAC now? AD797? I basically mostly care about the DAC now that my M-Stage will be here any day . Although right now I am enjoying the Playaz stuff right out of the Clip+


----------



## Spacehead

I soldered ADA4899-1 to single to dual browndog 
  I try it soon on my SMD CMOY

   
  I tried to lower output resistor value from 47 ohm to 10 ohm and that required soldering smd resistor parallel on top of each other. How much that increases inductance and capacitance?
  I did that because 47 ohm limits max current to about 200 mA with 9V rail voltage. Is my calculations right? 10 ohm should raise the current limit much higher. 
  I listen first a little AD8397 before I change ADA4899-1 in there. It has 32 mA Iq , but luckily I have 2500 mAh 1.2V AAs x 6 in series so I can run the amplifier very long still. 
   
  Here is ugly picture of the underside of my smd cmoy: 
http://i43.tinypic.com/21kar6p.jpg


----------



## Spacehead

And do you think BUF634 color the sound? I could add those buffers to my cmoy if it would increase sound quality. I don't want to have any laidback sound.


----------



## Spacehead

ADA4899-1YRDZ now running in my CMOY. on the ground is HA-5002x2 and AD8620
   
  DC offset was 7.3 mV on left and 1.3 mV on right. So pretty low. I give it 9V  
   
  Soundstage is impressive. Distortion seems to be very low. There is lot of details. Hihats and cymbals sound little metallic, like they should IMO. Sound is pretty effortless. ADA4899-1 seem to be very transparent op amp. I again can hear the DAC through my amplifier and filter stage in X-FI. 
  AD8397 has more bass punch. This is little flat. Really difficult to tell nuances because so high transparency. Mids are little recessed, I think. 
   
   
  This works very nicely. I don't use that amplifier much on the go because I don't have portable headphones that would benefit from a amplifier. But I still use batteries, I recharge them all the time. Now 200 mA NiMh, maybe 3 hours?


----------



## buz

You could wire 7 NiMH AAs in line and to get 7*2000mAh... At home, the bulk would not really matter much....


----------



## Spacehead

When batteries are in series their current does not add up, it is the same as one battery. 
   
  buz which one of your full size cans are best for op amp comparing? I will receive Sony MDR-V6 next week.


----------



## buz

Oh I am an idiot, I read you had a 200mA*h* battery and needed more runtime (and wasn't really thinking straight at that either, it's a decade since I last did that type of stuff) 
   
  I would say the D2000 is by far the best of the bunch but none of them is a truly analytical device (I have little use for that to be honest). The RX700 simply has too much bass so I guess the V6 would not be a bad if entry level approach....


----------



## headphoned

Quote: 





buz said:


> So which opamp do you have after the DAC now? AD797? I basically mostly care about the DAC now that my M-Stage will be here any day . Although right now I am enjoying the Playaz stuff right out of the Clip+


 

 AD797ANZ yeah =)
   
  It's great, a bit analytical but it's fine like this. I'm listening to Tom Waits, Brawlers (1st CD of the 3 CD set Brawlers, Bawlers & Bastards), it sounds awesome actually.

  
  Quote: 





spacehead said:


> And do you think BUF634 color the sound? I could add those buffers to my cmoy if it would increase sound quality. I don't want to have any laidback sound.


 


 Like everything, yes  But I'd like it to be inside the signal path, rather than outside, when it's a headphone amp


----------



## SpudHarris

D2000's are my weapon of choice also at the moment, more so than the HD600's. My set up is a Fi-Quest Headphone Amp with OPA637BP's in L/R - 4 x BUF634's (Stacked) per Channel and OPA637 in Ground. Using my 240gb imod with lossless tunage, this is heaven......


----------



## headphoned

Quote: 





buz said:


> So which opamp do you have after the DAC now? AD797? I basically mostly care about the DAC now that my M-Stage will be here any day . Although right now I am enjoying the Playaz stuff right out of the Clip+


 
   
  AD797 yeah =) Listening to Tom Waits, Brawlers (from the 3cd set Brawlers, Bawlers & Bastards) and loving it absolutely. Actually my CDP with CS4338 and NE5532 sounds fine too just slightly less weighty and refined 


  
  Quote: 





spacehead said:


> And do you think BUF634 color the sound? I could add those buffers to my cmoy if it would increase sound quality. I don't want to have any laidback sound.


 
   
  Yep, like everything really =) But I like it to be in the signal path rather than not, when it's a headphone amp  Perhaps there are better solutions, but they require building discrete buffers.


----------



## Apocalypsee

Quote: 





headphoned said:


> Glad that you like the LME49723
> 
> 
> 
> ...


 
  After been hearing it for a while, looks like the LME49723 clips at max volume, I have no idea why, checked everything from cold or bad solder but everything is OK. Dug out my old SB Live! 5.1 that have LT1364 SOIC, remove it and put it into this X-Fi Surround and no clipping at all. Maybe LME49723 isn't stable or something in the circuit


----------



## headphoned

As the NG98 DAC to lineout opamp, I'm still using the AD797ANZ and it is awesome (listening to Tom Waits, Brawlers, from the 3cd set Brawlers, Bawlers & Bastards that I just bought). The amp has the OPA132UA and it's awesome too (preferred this to the OPA627BP, don't know about the OPA827 instead).
   
   
  Yep, surely the BUF634 colors the sound, like anything else actually, even cables (actually cables color/degrade it a lot). But I still like it to be in the signal path, if it's a headphone amp 
   
  Sonic performance of the BUF634 depends on its bias level (set with that external resistor from pin 1 to pin 4). The higher the bias level, the better the sound. For efficient phones, better a high-biased (15 mA) single BUF634 than many stacked low-biased buffers.


----------



## headphoned

Quote: 





apocalypsee said:


> After been hearing it for a while, looks like the LME49723 clips at max volume, I have no idea why, checked everything from cold or bad solder but everything is OK. Dug out my old SB Live! 5.1 that have LT1364 SOIC, remove it and put it into this X-Fi Surround and no clipping at all. Maybe LME49723 isn't stable or something in the circuit


 
   
  What is the supply voltage, and is it the output of a DAC or some preamp stage? The LME49723 shouldn't clip more than the LT1364 with low voltages, anyway, at least looking at the datasheets, but sometimes real life is different..


----------



## headphoned

Maybe supply voltage is too low? Strange, since the LME49723 should work well with low voltages.
   
  I guess you had better use a rail-to-rail opamp, like OPA1612 or OPA1642


----------



## Apocalypsee

Quote: 





headphoned said:


> Maybe supply voltage is too low? Strange, since the LME49723 should work well with low voltages.
> 
> I guess you had better use a rail-to-rail opamp, like OPA1612 or OPA1642


 
  The supply voltage is 5V I think, my DMM acting weird so I cant measure it. The LT1364 also works at the same voltage rating (min 2.5V max 17V) but it worked fine. I ntoiced it even on XtremeMusic with LME49720, maybe its not suitable at low voltage, as I read somehwere said that National opamp needs rather high voltage (above 12V) to sound good


----------



## headphoned

Yep indeed, avoid LME's for that voltage, excepting the LME49721 which is a dual rail-to-rail opamp rated for 6V max. that sounds about as good as its higher voltage brothers.
   
  You can also try: OPA2727, OPA2340 (I'm using this in my modified C&C BOX and it's just fine, I liked it more than the LME49721 here), OPA2350, OPA2376, AD8616, AD8656.


----------



## Spacehead

Quote: 





headphoned said:


> As the NG98 DAC to lineout opamp, I'm still using the AD797ANZ and it is awesome (listening to Tom Waits, Brawlers, from the 3cd set Brawlers, Bawlers & Bastards that I just bought). The amp has the OPA132UA and it's awesome too (preferred this to the OPA627BP, don't know about the OPA827 instead).
> 
> 
> Yep, surely the BUF634 colors the sound, like anything else actually, even cables (actually cables color/degrade it a lot). But I still like it to be in the signal path, if it's a headphone amp
> ...


 

  OK I could try to fit that BUF634T into my cmoy. It would be really tight fit.


----------



## headphoned

Maybe first give a try to OPA552 (G>5) and TL051, why not


----------



## Apocalypsee

Thank you for the recommendation, I guess its suited for rail-to-rail opamp, I'll try others if I had the chance. For now the LT1364 really sounds great, no airy or wide soundstage as the National opamp but everything sounds better, as National opamp have a 'cold' sound signature and can sound quite shrill sometime, especially on bright system. My headphone is rather laid back but my speaker is very bright, the LT1364 makes it sounds great on both setup


----------



## headphoned

Yep, National chips are kind of cold (excepting maybe the LME49725 and LME49880). Why not try an OPA2132UA BTW, it you have it at hand. It sounds good even at that voltage, to me (if it doesn't clip). It has more warmth, sort of like the LT1364, and I think it's a bit better than the LT overall.


----------



## Apocalypsee

Will do, if only Texas Instrument could give free sample like Linear do. But as I read that OPA2132 is quite laid back, maybe it will suit my spekaer but maybe not for my headphone


----------



## headphoned

So they say... for me, the OPA2132P had more treble sparkle than the LT1364CN8, when I compared them directly inside my Super Pro @ 12V. LOL. For the record, between those two + the LM4562NA, I remember preferring the more involving OPA2132P.
   
  Actually the OPA2132 or OPA132 is indeed bassy without a good low-ESR electrolytic close to its power supply pins


----------



## Apocalypsee

I like treble sparkle, I do recall someone say so but most of them usually focused on its laidback-ness and 'tubby' sound. But it sounds like a 'fun' sounding opamp


----------



## headphoned

It is 
   
  Or maybe LM4562 & LT1364 are boring, LOL


----------



## buz

How big of a difference is there between the OPA2132 and the 2134 (ISTR that the 2132 was the better binned variant of the 2134....)?


----------



## headphoned

Not that much, the OPA2132 is a little bit smoother and more transparent. The single versions sound better.
   
  That aside, for me the main difference between OPA132 and OPA134 is in tonality. The 2 equates to more green in sound, meaning that whenever an opamp has a 2 or more I hear it as green  while 4 equates to blue


----------



## headphoned

So the OPA132 would be preferable both after a CS4398 and before a BUF634


----------



## buz

Well I would have the opamp after the CS4398 then feeding to the stock 2134 in the M-Stage. Probably wont roll that right out of the gate . Thinking I'll either go for LT1028C (as I already have them here) or AD797 for starters
   
  Not sure what the heck green and blue sound means though


----------



## headphoned

CS4398 and OPA2134 heh? Then also an OPA627 would be an idea  and the LM4562HA too.


----------



## buz

How much of a difference is the HA vs the MA (i.e. DIP, not metal) version of the LM4562? Those I can get locally, the other only from digikey&farnell sent from abroad which is expensive and slow... And of course, they only stock the 134 in DIP *GNAGNAGA*


----------



## headphoned

The LM4562MA/NA would be boring compared to the HA


----------



## buz

Ah well I decided to give a try to a pair of ebay AD797BRZ - leeperry said his sounded non-fake


----------



## leeperry

LM4562NA is the biggest example of clueless internet hype to me.


----------



## buz

That one at least is rather cheap, the HA version is pricey!


----------



## headphoned

One would have to compare them to some genuine AN(Z) 
   
  Anyway, it's a nice idea.


----------



## headphoned

Yep, but the TO99 LME49720 or LM4562 are worth their cost, to me.


----------



## buz

Genuine ANZs are out of stock at the local distributor - I may yet get a pair once they are around (wanna see what happens with them in the M-Stage  )


----------



## Spacehead

I added BUF634T to my smd cmoy with ground channel. It is now like PIMETA. 

 Sound improved a bit, bass got less sloppy. I think even when op amp has good output current they don't drive well enough low impedance loads. 
   
  And it can now drive my headphones into very high volume without any distortion! 
   

   
   
  And that ADA4899-1 works , offset is only 7 mV on left and 3 mV on right. So offset dropped a bit because op amp drives now 1K resistor. As you can see from the image feedback loop is very short. 
   
  Should I add a resistor from BUF634 output to -V ? Would 1K ohm resistor give it Class A biasing? It works now in wide bandwidth mode.


----------



## ROBSCIX

Quote: 





headphoned said:


> Yep, but the TO99 LME49720 or LM4562 are worth their cost, to me.


 


 You're right about that.  The TO-99 seem to offer great gains over the SOIC8 or DIP8.  I have built quite a few LME49720HA modules and one of my all time favorites the Dual LME49710HA module.
   
  Here is a shot of some units I built for an associate.


----------



## headphoned

Yup, they are very good chips. I keep being curious about the 4562HA, simply because 4562NA and 49720NA didn't sound the same to me, the 4562 being warmer tonally.
   
   
  Now I can't resist trying the OPA2822 in the DAC. Will report what I hear


----------



## headphoned

Heh, no. I'll give up the superfast & super unstable chips. Let's try LT1028ACN8 (to compare with the AD797ANZ in the DAC side) and LME49725 (amp) instead. =)


----------



## T.B.N.

Quote: 





spacehead said:


> It will be weak without proper ground channel. OPA132 cannot drive low impedance headphones properly. What headphones you have?


 


 I've only tried low impedance headphones (KSC75 and Sony MD7506). Is there something I need to change in the ground?
  
  Quote: 





headphoned said:


> I have used the OPA132UA and it was more than ok in my 24V CMOY, with my Senn. HD238, but admittedly it's not the most full sounding since it doesn't have the most output current. If you really want full sounding, try these: OPA551 (with more than 12V), TL052, TLE2062 (good for 9V), TLE2082. Also the OP275 drives headphones well with 24V of supply voltage, it was one of my favorites.
> 
> P.S. Currently I'm using two TL051 @ 24V


 

 Cool, I'll check them out. I am going to keep experimenting with the two I have for now (the other is an OPA227)


----------



## Spacehead

Buffering the virtual ground helps alot 
http://tangentsoft.net/elec/vgrounds.html
  Quote: 





t.b.n. said:


> I've only tried low impedance headphones (KSC75 and Sony MD7506). Is there something I need to change in the ground?
> 
> 
> Cool, I'll check them out. I am going to keep experimenting with the two I have for now (the other is an OPA227)


----------



## headphoned

Certainly it helps compared to a pair of resistors LOL 
   
   
  But it's simpler to use a TLE2426, followed by a pair of low ESR electrolytics, and works perfecly. I've never felt it was a limitation, even when using the OPA55x 200 mA output opamps.


----------



## T.B.N.

Quote: 





spacehead said:


> Buffering the virtual ground helps alot
> http://tangentsoft.net/elec/vgrounds.html


 


 I know very little, unfortunately, about basic electronics and circuits, just what I remember from high-school. Any recommended resources for teaching myself this stuff? Books? Websites?
   
  The cmoy is simple enough that I might be able to put in the buffer without fully understanding how the circuit works. Thanks for the help!


----------



## headphoned

Do you know the TLE2426? I think its application circuit is shown on Tangent's site. Use that one, it's perfect for a headphone amp. Only when you really squeezed a LOT of current from your CMOY would you appreciate the difference with an open-loop buffer. Actually in normal (and bordering on abnormal  operation a TLE2426 is even preferable, due to its very low output impedance.
   
   
  P.S. To me the TL051 is really special as a CMOY opamp


----------



## jcx

the TLE2426 has limited current capability - it limits at ~30mA - and will be pulled to the rail by more current demand - and it has to soak up both channels current at the same time
   
  to keep the splitter running in linear mode you need to add some series R from the TLE to the C midpoint
   
  to soak up 100mA current refered to above needs really large bypass Caps, up to ~ 10000 uF (for |Z| ~ 1 Ohm @ ~20 Hz), depending on headphone impedance and current requirements - and the Caps really don't need to be "low impedance" Caps by switching ps standards, anything less than ~ 1 Ohm esr would work OK


----------



## headphoned

I'd calculated that none of my headphones needs more than 6-7 mA (per driver) to produce already deafening sound pressures. That's well within the limit of the TLE, no!?  Plus, the low ESR caps (Panasonic FM 330uF in my case) from the "virtual ground" to each rail make up for any impulsive current request beyond the TLE's capability, if it should ever take place. Remember that we're talking of CMOYs anyway!


----------



## headphoned

Quote: 





jcx said:


> to soak up 100mA current refered to above needs really large bypass Caps, up to ~ 10000 uF (for |Z| ~ 1 Ohm @ ~20 Hz), depending on headphone impedance and current requirements - and the Caps really don't need to be "low impedance" Caps by switching ps standards, anything less than ~ 1 Ohm esr would work OK


 

 100 mA is absurdly too much anyway. To me the low ESR caps improve bass performance at normal (or too high) listening levels, since anyway the current drawn from the TLE has always remained within its specified limits apparently, as I've never ever heard my CMOY distort.
   
  I find, instead, that the output current that the opamp is capable of surely has an effect on sound quality - not by pushing distortion away, but by subjectively (thus undeniably) improving bass, dynamics, body.
   
  At any rate, an opamp like the TL051 for me has already enough body and bass dynamics to compete with a BUF634 driving efficient 32 ohm headphones, so no need to go beyond that for me.
   
  Besides, these two TL051 just sound better than that AD8397 that I used before in the same amp (which was tuned for the AD8397 originally).


----------



## headphoned

To be utterly honest, my CD player with its NE5532 has the most musical and emotional sound I've heard so far. There's something particularly seductive in its midrange, that I haven't managed to reproduce with any opamps in my three DACs so far, excepting only OPA1611 and EL2228 I believe, and maybe also the AD845KN.


----------



## Avro_Arrow

What you can do with this is replace the resistor divider with the TLE2426. Then you have a TLE that can do 250mA...
   
  You use the TLE output to drive the BUF.
  
  Quote: 





spacehead said:


> Buffering the virtual ground helps alot
> http://tangentsoft.net/elec/vgrounds.html


----------



## Spacehead

ADA4899-1 has excellent soundstage. Very accurate op amp too, my current favorite.


----------



## T.B.N.

I think I might be able to figure that out, but I don't understand. At all. How do I learn more about circuitry and grounds, etc? All I remember is from highschool four years ago...                                                 
  
  Quote: 





avro_arrow said:


> What you can do with this is replace the resistor divider with the TLE2426. Then you have a TLE that can do 250mA...
> 
> You use the TLE output to drive the BUF.


----------



## Mad Max

College Physics II
   
  Not sure what else yet. =P


----------



## headphoned

Please someone suggest me a fancy opamp with 5's and 3's in its number, that sounds as good as the NE5532, thanks
   
   
  I must get the JRC Muses 02 sooner or later


----------



## T.B.N.

mad max said:


> College Physics II
> 
> Not sure what else yet. =P





 oh mannn that means I have to take physics I and whatever math is required to take that, and I'm a film major!


----------



## Mad Max

College Algebra and Trigonometry?
  Easy as pie. In fact, I didn't even take College Algebra - I took a test that gave me the credit.


----------



## ROBSCIX

Quote: 





t.b.n. said:


> I think I might be able to figure that out, but I don't understand. At all. How do I learn more about circuitry and grounds, etc? All I remember is from highschool four years ago...


 

 Well start reading whatever you can on the subjects.  If you get stuck ask somebody with experience.


----------



## buz

How much DC offset on the line out of the DAC would be harmful to the amp ?


----------



## Spacehead

DC offset isn't harmful to amplifier. It becomes a problem when amplifier amplifies it and it gets to headphones. 
  
  Quote: 





buz said:


> How much DC offset on the line out of the DAC would be harmful to the amp ?


----------



## buz

That's what I wanted to hear  I hope the M-Stage is better than that 
   
  Edit: in fact, I get like 1 to 10mv (with like twice that going into it). All fine then


----------



## leeperry

the limit is said to be 20mV on forums, but most pros don't care if it's not >100mV.


----------



## buz

Yeah I was familiar with the 20mv, I think I read about commercial stuff that had more than that though .


----------



## ROBSCIX

This is why many designs use coupling capacitors on the outputs  or between amplification stages as they effectively stop all DC like a car hitting a brick wall.


----------



## Avro_Arrow

Like was said earlier...read...alot...
  Search for Chu Moy, Tangent, AMB, PASSDIY and Walt Jung.
  Read everything you find twice.
  Ask questions.
  Start soldering things together.
  Make mistakes
  Enjoy your successes.
   
   
  Quote: 





t.b.n. said:


> I think I might be able to figure that out, but I don't understand. At all. How do I learn more about circuitry and grounds, etc? All I remember is from highschool four years ago...


----------



## T.B.N.

avro_arrow said:


> Like was said earlier...read...alot...
> Search for Chu Moy, Tangent, AMB, PASSDIY and Walt Jung.
> Read everything you find twice.
> Ask questions.
> ...





 thanks for the encouragement. I just finished my first cmoy today, following the great write up on tangent's site. Sounds great for now, and adding two 9-V helped a lot. I think I'm going to find an old physics textbook and read through that before I go on to my next amp.


----------



## headphoned

I have never heard a DAC sounding as analog and warm-fluid-beautiful as my CD player, and that has a JRC NE5532.
   
  For instance, the NG98 DAC with the AD797 was similarly smooth and everything, but the analog feel was kind of missing, like some warmth. The AD797 (or LT1028 too, except that maybe this one is more musical) would go well in studio equipment, but I guess it's not impossible to realize why the NE5532 is far more widely used in amateur hi-fi, even very high-class.


----------



## ROBSCIX

That is not to say there aren't better opamps available.  The 5532 is the all time generic opamp used in everything from pro mixers to receivers.  I have a few but seldom use them in any designs...there are others I prefer more.


----------



## G.Trenchev

I like the NE5534 biased with 3mA.It's somewhat neutral and all-around capable with woody,punchy bass.Costs almost nothing compared to the performance offered.For the price of,say OPA134 I can get a bucket of 5534s


----------



## headphoned

Very interesting thanks! Biased with what, a resistor or a "constant current source"?


----------



## headphoned

Quote: 





robscix said:


> That is not to say there aren't better opamps available.  The 5532 is the all time generic opamp used in everything from pro mixers to receivers.  I have a few but seldom use them in any designs...there are others I prefer more.


 

 It depends. The problem (as I hear it) is that many opamps are less musical than a simple NE5532. I wanna try the NJM2114 when I get a chance


----------



## G.Trenchev

A resistor.Should try CCS,but I'm lazy


----------



## Spacehead

Do you think newest op amps benefit from class a biasing?
   
  And can BUF634T biased to 30 mA?


----------



## headphoned

No, I think they do NOT.
   
   

 Thank you G.Trenchev, I have a couple of TI NE5534 and I'll try them biased into class-A as soon as I have the chance.  The AD797 is very interesting by not utterly satisfying. I will compare NE5534 biased into class-A to AD845KN, both being powered with 24V. Although probably a pair of OPA1611 would make me happy for a lifetime (based on former experience)


----------



## SpudHarris

I generally agree that newer opamps don't benefit from 'Class A biasing'. however I tried this with the ADA4627-1 last night and I found it to sound a lot nicer, I like that chip anyway but it sounded more detailed and airy.
   
  I've ordered another couple to stick on low profile Soic to DIP adapters which will allow me to close my amp when inserted into my Class A DIP Socket adapters


----------



## Spacehead

Quote: 





spudharris said:


> I generally agree that newer opamps don't benefit from 'Class A biasing'. however I tried this with the ADA4627-1 last night and I found it to sound a lot nicer, I like that chip anyway but it sounded more detailed and airy.
> 
> I've ordered another couple to stick on low profile Soic to DIP adapters which will allow me to close my amp when inserted into my Class A DIP Socket adapters


 
   
   I think discrete buffers in PPA v2 Sound quite cold even with 40 mA bias. I have 2SA1011 and 2SC2344 there.
 I just removed Class A biasing from my PPA v2 hoping to get smoother sound that way. I have ADA4627-1ARZ on left and right + LT1364 on ground.


----------



## SpudHarris

Quote: 





spacehead said:


> I think discrete buffers in PPA v2 Sound quite cold even with 40 mA bias. I have 2SA1011 and 2SC2344 there.
> I just removed Class A biasing from my PPA v2 hoping to get smoother sound that way. I have ADA4627-1ARZ on left and right + LT1364 on ground.


 

 Spacehead, I gotta ask this coz it's been bugging me for ages...... I too had a PPAv2 for ages but it used all single chips and no doubles. You keep quoting doubles in your ground channel. Was there a different version or did you mod yours in some way? Just curious coz I often wished I could use/try an OPA2107 in ground on mine as it was once my all time favourite ground in my P3+.


----------



## Mad Max

Quote: 





spudharris said:


> I generally agree that newer opamps don't benefit from 'Class A biasing'. however I tried this with the ADA4627-1 last night and I found it to sound a lot nicer, I like that chip anyway but it sounded more detailed and airy.
> 
> I've ordered another couple to stick on low profile Soic to DIP adapters which will allow me to close my amp when inserted into my Class A DIP Socket adapters


 

 Oh really? Now I have to try that.
  I was going to scavenge resistors from some old crap anyway.
  It doesn't start sounding dry like 797, does it?


----------



## headphoned

If the ADA4627-1 really benefits that much from having its output stage forced into class A, then it must be a flawed design in the first place 
   
  I'll stick to OPA1611, LME49880, AD845 etc.


----------



## Spacehead

With simple adapter can duals be used in PPAv2. If one uses sockets, one little adapter doesn't degrade sound too much. 
 Here is the link for sijosae's idea of dual to single adapter. It requires two sockets. 
http://www.headphoneamp.co.kr/bbs/zboard.php?id=diy_sijosae&page=1&sn1=&divpage=1&sn=off&ss=on&sc=on&keyword=dual%20to%20single&select_arrange=headnum&desc=asc&no=71
  Quote: 





spudharris said:


> Spacehead, I gotta ask this coz it's been bugging me for ages...... I too had a PPAv2 for ages but it used all single chips and no doubles. You keep quoting doubles in your ground channel. Was there a different version or did you mod yours in some way? Just curious coz I often wished I could use/try an OPA2107 in ground on mine as it was once my all time favourite ground in my P3+.


----------



## jcx

its acutally possible for a op amp to have "perfect" output with the manufacturer's intended Clas AB output stage bias driving a load into its Class B range and for a circuit using that op amp to be sensitive to Class A output bias of the op amp
   
  in Class AB there is nonlinear "half wave rectified" current in each of the +,- supply pins and traces - if the power traces couple to other parts of the circuit through bad routing/layout or poor psrr and inadequate regulation then the nonlinear currents could add distortion to the signal
   
  biasing the op amp output into Class A, if there is any ps trace coupling it will at least be linear and only cause small gain or crosstalk changes rather than nonlinear distortion
   
  this thread really needs a floating banner saying It Depends on the rest of the circuit and application


----------



## Spacehead

I increased class a bias to 60 mA for discrete PPA v2 buffers. They will run extremely hot. I also biased AD8597s to 3.6 mA and LT1364 to 2.5 mA. 
  Now the highs are less piercing, sound is a lot smoother. It is still far away from Mosfet smoothes. BJTs seem to need high bias to sound good.


----------



## headphoned

How did you manage to put bipolar opamps in a PPA v2? I know that it would use jung multiloop feedback, thus make it impossible to use bipolars.
   
   
   
  BTW, I really urge anyone who cares for their CMOYs  to try the TL051 (or TL052) in them


----------



## headphoned

Anyway to me bipolar opamps (the good ones, including the 5532/5534/2114) always tend to sound better & smoother than the FET ones, and I really never bias them into class A 
	

	
	
		
		

		
			




   
   
  jcx's argument is interesting anyway, except that he seems to be assuming that every circuit except his own have poor layout, hehe.


----------



## headphoned

Couple o' great sounding, low distortion FET opamps: AD845KN (single), LME49880 (dual). Probably my overall favorites. Secondly come the OPA827, TL051/052, OPA1641/1642, OPA132UA.


----------



## Spacehead

By changing R2 39K , R4 33K , R3 10K . That way I have low offset with bipolar op amps, about 10 mV. 
  Quote: 





headphoned said:


> How did you manage to put bipolar opamps in a PPA v2? I know that it would use jung multiloop feedback, thus make it impossible to use bipolars.
> 
> 
> 
> BTW, I really urge anyone who cares for their CMOYs  to try the TL051 (or TL052) in them


----------



## headphoned

I see. Anyway, I don't know about the AD8597, but the LT1363/4 can sound a little hard in improper applications (remember it's not made for audio). Maybe it rings a bit... If I were you, I'd use the OPA1611 =)


----------



## Spacehead

My smd cmoy with BUF634T (in wide bandwith, full 15 mA Iq) sounds better than PPA v2 and PRR-Szekeres. 
   
  It is most accurate sounding and still not too bright.
   
  headphoned, order ADA4899-1 and try that on your cmoy. It might work or not, but on my smd cmoy it works and doesn't heat up.


----------



## headphoned

I used various high-speed opamps and almost always found them to sound unnatural. If I want a high-current high-speed opamp, I'll put a pair of THS4051 inside my CMOY and power them with 24V, or that adapter I made with two LMH6654's at 12V. Those could be serious contenders for the TL051 in all-round sound quality, according to former experience


----------



## headphoned

Hmm you gave me a good idea. The THS4051 should not have such an immense DC offset (LOL) so perhaps I could try it. But I KNOW that you seriously miss my point when I recommend the TL051.


----------



## Spacehead

I need to order TL051 but I doubt it. I like these high speed op amps. They sound good with electronic music. 
  
  Quote: 





headphoned said:


> Hmm you gave me a good idea. The THS4051 should not have such an immense DC offset (LOL) so perhaps I could try it. But I KNOW that you seriously miss my point when I recommend the TL051.


----------



## headphoned

I like acoustic and vocal music, so transient precision is important for me, but also refinement. Generally I'm more for the so-called "laidback BB sound".


----------



## headphoned

Most of all, I always compare the sound of my CMOY (or other headphone amp, driving my HD238 at the moment, since the HD650 lies unused nowadays) to that of my speaker system. My ultimate goal is always to get the same degree of emotion when using headphones 
   
   
  I will say that I really like my C&C BOX modified with two OPA2340 (tried many), and new electrolytic caps. The 1A of output current per channel can be heard well. Sounds smooth and realistic.


----------



## headphoned

Just compared the 24V-powered TL051 CMOY to my modified C&C BOX to my stock Little Dot Micro+.
   
  The CMOY sounds best, it's easy to hear  with the most "life" and least plain "hi-fi sound". Kind of tubey perhaps  but open too and tight in the bass. At the same time it has a fullness and sense of dynamics that rivals those of the C&C. Ah, and the LDM+ wasn't that bad anyway  just not the most open nor the warmest of sounds.


----------



## T.B.N.

Quote: 





headphoned said:


> Just compared the 24V-powered TL051 CMOY to my modified C&C BOX to my stock Little Dot Micro+.
> 
> The CMOY sounds best, it's easy to hear  with the most "life" and least plain "hi-fi sound". Kind of tubey perhaps  but open too and tight in the bass. At the same time it has a fullness and sense of dynamics that rivals those of the C&C. Ah, and the LDM+ wasn't that bad anyway  just not the most open nor the warmest of sounds.


 

 Nice! Is it a stock CMOY with a bunch of batteries or something else?


----------



## headphoned

It was a "special order" from a ebay guy from the US who used to make and sell CMOYs on pcb designed by himself. It has a (black colored) dual layer pcb with ground plane, partly SMD partly normal components, Panasonic FM caps (these were changed by me with other values), 1uF Wima + 1uF tantalum + 100nF ceramic decoupling caps, TLE2426, balanced input impedances (I requested that it would accept the AD8397, which is what it had originally), and no DC blocking caps in the signal path. The electrolytics are arranged like this: 1 on the full input voltage before the TLE, and 1 per each split rail after it. All's being powered with a good 24V switching PSU (that came with a Shellbrook Ascent which I have no more).


----------



## T.B.N.

not you average cmoy then


----------



## headphoned

Yep, but the TL051 is an opamp that may be used in every CMOY, and suitable even for a 9V supply voltage. And it sounds so good 
   
   
  I recommend trying the TLE2062 too =)


----------



## T.B.N.

Cool, which kind should I get? "CD" "MD" etc...
   
http://mouser.com/Search/Refine.aspx?Keyword=TLE2062


----------



## headphoned

The TL051CD and TL052CD, or ACD if you want. 
   
   
  & the TLE2062CP or IP


----------



## headphoned

I just saw (in the datasheet) that a TL051 contains only 20 transistors (and a TL052 34, that is, not twice as much, meaning that there isn't completely independent circuitry for the two channels - so better stick with the TL051). Maybe the small transistor count is part of the reason for its musicality 
   
   
  P.S. The TLE2062 has 42 transistors; funnily enough, the TLE2061 has 43.  Anyway the TLE2062 certainly doesn't sound as rich or tubey as the TL051.


----------



## T.B.N.

Quote: 





headphoned said:


> I just saw (in the datasheet) that a TL051 contains only 20 transistors (and a TL052 34, that is, not twice as much, meaning that there isn't completely independent circuitry for the two channels - so better stick with the TL051). Maybe the small transistor count is part of the reason for its musicality
> 
> 
> P.S. The TLE2062 has 42 transistors; funnily enough, the TLE2061 has 43.  Anyway the TLE2062 certainly doesn't sound as rich or tubey as the TL051.


 

 Cool, I'll get both 
	

	
	
		
		

		
			





 It's fun to try them out and compare, and why not, they're only a few bucks.
   
  Is the TLE051 a single channel only? Also its surface mount, unless I get the CP or ACP.


----------



## Spacehead

I have 5 TLE2062 but the specs are so bad that I haven't bothered to try it. 
   
  I got now ADA4841-1 working in PPAv2. 
   
  It works as a pre amp to Szekeres Class A Mosfet circuit. Sound is smooth with Panasonic FC output caps.


----------



## headphoned

Bad? What? The around 80 mA of output current while maintaining FET inputs? It must sound bad indeed. Do you know that digital audio slews at no more than 0.7 V/uS ? We're not talking of "good" and "bad" here, but what is more or less suitable for a CMOY. A TLE2062 is more suitable than many others, and sounds better. I prefer a pair of TL051 though.
   
   
   
  BTW I just repaired my Super Pro 707, replaced all film caps with Wima FKS (filter) and MKS (bypass), replaced all electrolytics, soldered an adapter with a pair of LT1363 on it, with Wima bypass directly upon the browndog, and now I await a pair of Solen caps for coupling the line outs, and some new RCA plugs. =)


----------



## Avro_Arrow

You should try building a three channel Szekeres so you can get rid of the output cap 
	

	
	
		
		

		
		
	


	



  
  Quote: 





spacehead said:


> I have 5 TLE2062 but the specs are so bad that I haven't bothered to try it.
> 
> I got now ADA4841-1 working in PPAv2.
> 
> It works as a pre amp to Szekeres Class A Mosfet circuit. Sound is smooth with Panasonic FC output caps.


----------



## Spacehead

Could you help me on that one? 
   
  I have third channel with BUF634T and op amp. I have now only connected input ground and output ground. How should I connect the biasing circuit to third channel for getting output DC voltage to zero?
  Quote: 





avro_arrow said:


> You should try building a three channel Szekeres so you can get rid of the output cap


----------



## headphoned

ouch, sorry


----------



## Avro_Arrow

The third channel, as you guessed, is ground.
  Here is a schematic...you can sub in whatever MOSFET and current source you use,
  this will give you the basics.
   
  Credit goes to the author, not me.
   
  This is really meat for a different thread...you can PM me if you want to discuss it further.
  
  Quote: 





spacehead said:


> Could you help me on that one?
> 
> I have third channel with BUF634T and op amp. I have now only connected input ground and output ground. How should I connect the biasing circuit to third channel for getting output DC voltage to zero?


----------



## ROBSCIX

Quote: 





headphoned said:


> It depends. The problem (as I hear it) is that many opamps are less musical than a simple NE5532. I wanna try the NJM2114 when I get a chance


 
  Well that is a subjective opinion, I wouldn't call the 5532 musical.


----------



## headphoned

Wouldn't you???!!! 
   
  Anyhow yes, _everything_ is subjective. Well, at least a lot of people consider the NE5532 musical like I do.


----------



## headphoned

As an upgrade to the NE5532/5534 in many areas I like the LT1363/1364.


----------



## SpudHarris

Anyone got a view on the AD8622?
   
  It came with my ADA4627 (BRZ's) today but I can't recall why I ordered it? I'll solder it up and have a listen later....


----------



## headphoned

.28 V/uS and 540KHz of bandwidth - that starts to be slow, LOL.
   
   
  Personally anyway the AD opamps don't make me too happy, excepting the AD845KN which is quite good (overall preferable to the AD797 for +/- 12V or more, to me). I do acknowledge that I have not heard the ADA4627-1 yet.
   
  I'm impatient to get the missing parts & complete my DAC, to hear how it performs with those LT1363 without sockets and stuff.


----------



## bcpk

Could anyone suggest an op-amp for my MiniBox E+?


----------



## headphoned

Depends on the supply voltage and if it wants FET opamps. You can safely use the OPA827 anyway, which is sonically a good combination with the BUF634. Another good choice is the OPA132UA (don't overlook this - it sounds better than the OPA827 in some ways, so judge for yourself).
   
  For tubey sound, try a couple of TL051. 
	

	
	
		
		

		
			




   
   
  EDIT: You can use the OPA228P too.


----------



## SpudHarris

Quote: 





headphoned said:


> Another good choice is the OPA132UA (don't overlook this - it sounds better than the OPA827 in some ways, so judge for yourself).


 
   
  Ahh, those were the days when Andrea used to post this every day


----------



## headphoned

Did I? Anyway it's a good chip, not the best ever seen or heard.


----------



## SpudHarris

If you remember I was totally in agreement, I still like the OPA132UA very much. In the right place it is beautiful. In my Fi-Quest the OPA637's are never bettered but in my P3+ amps (which won't work with the 637's) I just adore the ADA4627-1BRZ's and also the OPA2111AM.
   
  You really have to try the ADA4627's.....


----------



## headphoned

Not that easy right now, but I'll try 
   
   
  The OPA2111KP had a serious lack of midbass to me?


----------



## headphoned

If someone could compare OPA1611 and ADA4627-1 ...


----------



## Mad Max

Quote: 





bcpk said:


> Could anyone suggest an op-amp for my MiniBox E+?


 

 ADA4627-1BR will sound the very best. What source are you using it with?
   
  I find AD744JN or AD744AH to have the best tonal synergy with ipod classic 6g.


----------



## SpudHarris

Quote: 





headphoned said:


> If someone could compare OPA1611 and ADA4627-1 ...


 

 I have both of these but the ADA4627's are just better, fuller. The OPA1611's are nice but much like the OPA132UA they only shine in paricular circuits or applications, to my ear in comparison they are bland. What I have found though is that they are one of the best opamps for ground in both the P3+ & Fi-Quest.
   
  The ADA4627's sound just fantastic no matter what I've used them with. Ryuzoh who developed the Fi-Quest (& really knows his stuff) told me that they bettered the OPA637's, personally I think they are as good but just different. In my experience anyhow.


----------



## headphoned

To me, the OPA1611 is a very neutral, coherent chip. I like BB chips because they sound subtle, whereas the AD chips tend to sound a bit crude. I will give that ADA4627-1 a try. The OPA1611 had a full sound to me, with transparent timbre.


----------



## headphoned

The OPA627 doesn't compare with the OPA1611, anyway.


----------



## bcpk

Quote: 





mad max said:


> ADA4627-1BR will sound the very best. What source are you using it with?
> 
> I find AD744JN or AD744AH to have the best tonal synergy with ipod classic 6g.


 

 iPod Video 5G and Etymotic ER-4P. Do any of these reduce the hiss of the MiniBox? It's pretty bad.


----------



## headphoned

I think you don't need such an amp for those phones, since they look very efficient, hence the hiss. 
   
  Anyway the OPA827 will be best with the BUF634 in terms of synergy.


----------



## headphoned

The LT1028ACN8 would have a great synergy with the BUF634 too. You can try that. It has extremely low noise. And can sound magical.


----------



## Mad Max

Quote: 





bcpk said:


> iPod Video 5G and Etymotic ER-4P. Do any of these reduce the hiss of the MiniBox? It's pretty bad.


 

 The 75-ohm button on the minibox-E+ should help as well as changing opamps. 4627-1 will reduce hiss. If you are going to use the ER4, you may want the warmer A version of 4627-1 than the more neutral B version. I read those etys are real bright and the B version may leave the Minibox without enough warmth for your 'phones or taste, though I can't say for sure. I use RE0, RE252, and MTPC.
  AD744 will not have a lower noise floor than 8610 and probably not the same synergy with the 5g classic as the 6g.
  LT1028 kind of works but it will be underpowered and will give you sine sweeps not to mention a big loss of detail compared to 8610, 744, and especially 4627-1.


----------



## headphoned

What? The LT1028 less detailed than an AD8610? It's totally the opposite, IMHO. I think you're confusing aggressiveness with detail. Midrange articulation, for instance, is far superior with the LT1028 than with the AD8610/8620. And I don't remember the AD746 (dual AD744) as being ultradetailed, too. I would say that detail is a strong point of the LT1028


----------



## headphoned

At the end of the day, a couple of LT opamps, namely LT1028 and LT1363, are some of the best I've ever heard. Plus they happen to have a kind of synergy.
   
  After the Super Pro is repaired, I could get a new NG98 (mine is no more  probably with the AD1852 (just for a change), and give it the LT1363 for the line out, and the LT1028 for the headphone amp (with BUF634).


----------



## buz

What the heck did you to your NG98?


----------



## headphoned

Broke it intentionally after something went slightly wrong, lol. I'm toooooo emoooootionaaaaallll with these things, hehe


----------



## bcpk

Quote: 





mad max said:


> The 75-ohm button on the minibox-E+ should help as well as changing opamps. 4627-1 will reduce hiss. If you are going to use the ER4, you may want the warmer A version of 4627-1 than the more neutral B version. I read those etys are real bright and the B version may leave the Minibox without enough warmth for your 'phones or taste, though I can't say for sure. I use RE0, RE252, and MTPC.
> AD744 will not have a lower noise floor than 8610 and probably not the same synergy with the 5g classic as the 6g.
> LT1028 kind of works but it will be underpowered and will give you sine sweeps not to mention a big loss of detail compared to 8610, 744, and especially 4627-1.


 

 Thanks for the suggestion. Now I just don't know where to buy them. The LME49710 was suggested for the MBE+ and it's easily available on eBay, but I can't seem to find any of the other opamps listed here with such ready availability.


----------



## headphoned

I don't know why you listen to his suggestions and not mine, lol. Anyway the ADA4627-1 is specified at +/- 5V or more, check supply voltage or you're gonna waste your money. The OPA827 is specified at +/- 4V or more. I still recommend the latter. 
   
   
  The LME49710 is a mediocre choice. You can consider the LME49710HA though, put on proper adapters TO99 to DIP. Specified from +/- 2.5V


----------



## headphoned

To me the ADA4627-1 looks like another OPA627. I'm sure it's going to sound clear and unmusical. Luckily I have a number of OPA827 with me, in case a FET opamp is what I strictly need.


----------



## SpudHarris

ADA4627-1 is a detailed chip for sure but it's not unmusical by any stretch of the imagination, I love it.
   
  I have 2 x P3+ amps - One for a laid back listen and one for monitoring or critical listening.
   
  a) OPA2111AM (TO99) - BUF634 (Stacked) - OPA627's in G/VG
   
  b) ADA4627-1BRZ - BUF634 (HiC) - OPA627's in G/VG
   
  Both amps sound fantastic but different......


----------



## headphoned

So you're putting it on the same level as a OPA2111AM. Therefore, OPA1611 and LME49720HA (two of my favorites) are definitely competitive with the ADA4627-1. Most probably the AD845KN too


----------



## Spacehead

I think I broke two ADA4627-1B 
   
  What a pain!!


----------



## SpudHarris

Quote: 





headphoned said:


> So you're putting it on the same level as a OPA2111AM. Therefore, OPA1611 and LME49720HA (two of my favorites) are definitely competitive with the ADA4627-1. Most probably the AD845KN too


 

 It's all subjective isn't it. you most definately have your favourites as they have synergy with all the other parts in the chain i.e. Source, Circuit, Phones etc.....
   
  The OPA2111AM is the most beautiful chip in my P3+. It is detailed yet warm and musical, it is a full fun sounding chip. In your set up it may sound pants 
   
  I must try the AD845KN.....


----------



## SpudHarris

Quote: 





spacehead said:


> I think I broke two ADA4627-1B
> 
> What a pain!!


 

 How? Overheated?
   
  I used to do that on a fairly regular basis before discovering Cardas Solder...... It's great to work with and runs real fast at low temp even.


----------



## headphoned

Quote: 





spudharris said:


> It's all subjective isn't it. you most definately have your favourites as they have synergy with all the other parts in the chain i.e. Source, Circuit, Phones etc.....
> 
> The OPA2111AM is the most beautiful chip in my P3+. It is detailed yet warm and musical, it is a full fun sounding chip. In your set up it may sound pants
> 
> I must try the AD845KN.....


 
   
  Well said. 
   
  I use a pair of bookshelf speakers, anyway. Nowadays I only use my phones in a secondary system & driven by the CMOY. I do plan to break out my HD650 again some time soon 
   
   
  Try the EL2228 too, it's a great chip: full & fluid sounding yet quite resolving  but pay attention to the 4.5 uA bias current.


----------



## Mad Max

Quote: 





headphoned said:


> I don't know why you listen to his suggestions and not mine, lol. Anyway the ADA4627-1 is specified at +/- 5V or more, check supply voltage or you're gonna waste your money. The OPA827 is specified at +/- 4V or more. I still recommend the latter.
> 
> 
> The LME49710 is a mediocre choice. You can consider the LME49710HA though, put on proper adapters TO99 to DIP. Specified from +/- 2.5V


 

 This guy, wait 'til you hear 4627-1, then you'll eat your words, lol. 
	

	
	
		
		

		
		
	


	



   
  Head-Direct told me Minibox-E+ is 7.4v
   
  49710HA will not fit with TO-99 adapters, the leads have to be bent and trimmed little by little very carefully.
  Other Minibox-E+ users found OPA627 to sound no better than AD8610 in this little amp. 8610 gives the best battery life, but certainly not the best sound.
   
  I also did not imply 744 being ultra-detailed. LT1028 is noticeably more detailed than the plastic dip J version but in my Compass DAC only. Minibox-E+ is just not suited for 1028 and 797.


----------



## headphoned

Quote: 





mad max said:


> This guy, wait 'til you hear 4627-1, then you'll eat your words, lol.
> 
> 
> 
> ...


 

 I know this for a fact: the ADA4627-1 can't but have a similar tonality to the OPA627, and I never found the OPA627 enjoyable (musical) enough. 
   
   
  Yep, the LT1028ACN8 is crystal clear yet remains fluid and musical. I think the OPA1611 is just a bit better (rounder & more luminous mids).
   
   
   
   
  P.S. The TL051 are simply magical & heavenly sounding in my CMOY (just been listening to Tom Waits, "Bawlers", 2nd disc of the 3 CD set "Orphans"). I never thought my CMOY could sound this good.


----------



## headphoned

BTW based on my memory I would much prefer to use a LME49880 (FET opamp with very low distortion & natural sound) to a AD746. I guess I'd prefer the TL052 too


----------



## headphoned

Also, I notice that the OPA1641/1642 has completely disappeared from the discussion. It's just a pity, because that's one very good FET opamp, and one that is rail-to-rail and low-power-consumption too, thus potentially perfect for those portable amps. I do find that the bipolar counterpart the OPA1611/1612 sounds better, as usual - more refined.


----------



## Mad Max

Too much speculation there. Wait 'til you hear it, lol.
   
  I have OPA1641. It is good and better than TLE2141A which I used the most before but it cannot touch 4627-1. 
	

	
	
		
		

		
		
	


	



  I haven't compared it to AD744AH or either of the other grades in output bypass now that I think about it. It certainly betters the J version.


----------



## headphoned

The TLE2141 is mediocre, the OPA1641, OPA132UA and TL051 being far better. The LME49880 is also another world, however dual (what's this _mépris_ for anything "dual", BTW)
   
   
  I'm of the opinion that when a DIP opamp don't please your senses, you can't fix it by replacing its package with the TO99, heh. Sure, the TO99 sounds a bit better, but it's only worth the investment when you liked the DIP version of the same opamp in the first place.
   
  For instance I liked the LME49720 and the LME49720HA is one of my favorites; but I didn't like the AD744/746 so I don't want to spend money on the TO99 version of the AD744, let alone using it with outputs bypassed and nearly no output current. There simply are better opamps nowadays, like the OPA1611, or if you must go FET, the OPA1641, OPA827, and possibly ADA4627-1.
   
  Still interested in hearing these super LME49990's, which are bipolars so they may be my thing


----------



## Sebhelyesfarku

Ok, opamp gurus floating in lotus position over a brown dog, what would be a good swap for a NE5532 in the input section of a headphones amp? I'd like to keep the lush, musical sound, just improve it. I'd prefer a dual chip on DIP8, don't want to mess with adapters... just plug'n'play.


----------



## K3cT

LT1364


----------



## headphoned

I agree about the LT1364, & would add the LME49880, TL052, LME49725, LME49723. 
   
   
  Especially the LME49725


----------



## Mad Max

Quote: 





headphoned said:


> ...
> I'm of the opinion that when a DIP opamp don't please your senses, you can't fix it by replacing its package with the TO99, heh. Sure, the TO99 sounds a bit better, but it's only worth the investment when you liked the DIP version of the same opamp in the first place.
> ...


 

 I like AD744


----------



## headphoned

Ok.  To me the AD746 was much too cold. Even the AD8620, which is not a very colorful chip, sounded more musical. The OP275, as I remember, was the most musical of this trio.
   
   
  Nowadays I'd use the LME49725 or LME49880, or the OPA1612 naturally =)


----------



## headphoned

I highly recommend trying the EL2228 too. It only exists as a dual opamp but it's worth it 
   
   
  The TL051 still amazes me in the CMOY, it is just perfect 
   
  If you like musical and lush, but clear, try TL052 and TL051 also in line stages.


----------



## leeperry

LT1364CN8/OPA2132P are good starters.


----------



## headphoned

Yes they are, but I still think that LME49725 & LME49880 are better sounding opamps overall. The EL2228 is slightly less easy to use but it's the most detailed dual opamp I know.


----------



## leeperry

he said _"don't want to mess with adapters",_ and none of the 3 chips you mentioned is available in DIP8 form 
	

	
	
		
		

		
		
	


	




 if it were about using adapters, using single chips would be a far smarter move...LT1028, ADA4627-1, LT1363, OPA132, OPA827 etc etc


----------



## Sebhelyesfarku

Ok, thanks for the replies, I'll give a try for the LT1364, swap'n'play. Who knows, later I may catch the rolling fever and stick in crazy stuff on crazy adapters (I hope not  )


----------



## headphoned

In that case you can try the LT1364, LT1057ACN8, OPA2132P and the TL052CP (or ACP), then choose yourself


----------



## buz

Or you could try your luck with the ones already soldered to adapters on sold ebay...


----------



## leeperry

yes, clearly the cardas eutectic solder is a godsend! the usual 60/40 stuff takes forever to melt..
   
  anyways: 


   
  more bass than 1363/1028, would you believe that? SS is also even better than 1363...there used to be some very harsh/edgy upper mids when I first tried it, but either my brain got used to them or they magically "burned in"? 
	

	
	
		
		

		
			




   
http://www.diyaudio.com/forums/digital-source/105512-ad845-drop.html#post1273080
   


> The 845 is more shouting, unforgiving, and it sounds if there is some more distortion at the higher frequenties


 
   
  it still seems less colored than 1363, and one of my current test songs is "Boards of Canada - Twoism\01. Sixtyniner.flac"...this track kinda lacks dynamics when the breakbeat shows up in the intro on the 1363, I've heard it far more overwhelming...and it's back w/ a vengeance on 845, which would appear to be a close cousin of 797...besides KN is its highest grade, and it's only available as DIP8.
   
  You know you're obsessed about opamps when you solder them at midnight and try them at 3AM...I'm currently listening to ADA4627-1, and I've also put together some LT1360CS8...


----------



## Sebhelyesfarku

Quote: 





leeperry said:


> You know you're obsessed about opamps when you solder them at midnight and try them at 3AM...


   
   But you can quit anytime you want, no?


----------



## leeperry

sebhelyesfarku said:


> But you can quit anytime you want, no?


 
  I'll have to, I really don't like ADA4627-1A...some sort of OPA827? it's got BB written all over it 
	

	
	
		
		

		
		
	


	



   
  that "plasticky" sound I really hate...LT1360 is a sub-par LT1363, and AD845 has that nasty distortion in the upper mids/ trebles...it does wonders on 70's music(like a "perfect" tube!), but it makes classical music very harsh and unrefined 
	

	
	
		
		

		
		
	


	



   
  so far nothing beats LT1363 to my ears


----------



## Mad Max

Quitting is blasphemy. 
	

	
	
		
		

		
		
	


	



   
  ADI and the like will not stop developing more opamps over time.
Perhaps a vacation might not be a bad idea for leeperry. =P


----------



## leeperry

hehe, well 1363 doesn't have a high PSRR so it does need a very clean environment, but its pros have been extensively documented before: http://www.head-fi.org/forum/thread/89813/lt1363-opamp


----------



## Spacehead

detailed but smooth sounding chip ADA4898-1 
  maybe little lifeless
  now on my PPA v2. listened to it all night


----------



## SpudHarris

Just got 2 x OPA637AM's (TO-99) for use in my Fi-Quest. They arrived with 2 x Nichicon caps (Audio KT 33/50 (M) if that means anything at all to you guys. I've not yet got into bypassing etc yet but assume this is what they are for.
   
  Can someone clarify where I would use them, there is one for each opamp. I'd have a stab at +in & -in (pins 2-3) but I'd be guessing........
   
  Like to get into this at some point so this could be a good place to start, any help would be greatly appreciated


----------



## leeperry

one thing really not clear to me is that 1028A was making static
 pops when my bathroom neon turned off or my fridge turned on...and
 this doesn't happen whatsoever on OPA2604/AD845/LT1363, so much for PSRR?! maybe coz 1028 is a negative feedback opamp?
   
  my HD2 soundcard was also making nasty pops in the very same situations..the mysteries of audio


----------



## ROBSCIX

Quote: 





spudharris said:


> Just got 2 x OPA637AM's (TO-99) for use in my Fi-Quest. They arrived with 2 x Nichicon caps (Audio KT 33/50 (M) if that means anything at all to you guys. I've not yet got into bypassing etc yet but assume this is what they are for.
> 
> Can someone clarify where I would use them, there is one for each opamp. I'd have a stab at +in & -in (pins 2-3) but I'd be guessing........
> 
> Like to get into this at some point so this could be a good place to start, any help would be greatly appreciated


 

  
  You can use them for various tasks but the circuit needs gains of 5 or better as the OPA637 is not internally compensated.
  I have a set of OPA637SM and they sound great but can only be used in certain circuits.


----------



## Spacehead

OPA637AU works well in my PPA v2 with gain of 51K/15K = 4.4X 
   
  It sounds pretty nice too. Details aren't as clear as they are with ADA4627-1 though, but almost.


----------



## SpudHarris

Quote: 





robscix said:


> You can use them for various tasks but the circuit needs gains of 5 or better as the OPA637 is not internally compensated.
> I have a set of OPA637SM and they sound great but can only be used in certain circuits.


 
  Thanks Rob,
   
  yeah been using the BP in my Fi-Quest for a while on and off it has a adjustable gain switch which has to be on the highest setting to use them. What do you think the electrolyics that came with them were for?


----------



## K3cT

I doubt it's for bypassing. Ceramic or film is more suitable for this since it comes in very low values and the footprint is small.


----------



## SpudHarris

These are tiny. Small as the BG NX's used for imod LODs.....
   
  I'm flattered that they sent them, just wouldn't mind knowing what for? I have sent an e-mail but no response yet so thought I'd ask the people in the know 
   
  Wonder if I'll tell any difference between the OPA637BP's and AM's? There is a difference between the OPA2111KP and AM's so I'm hopefull....


----------



## ROBSCIX

Quote: 





spudharris said:


> These are tiny. Small as the BG NX's used for imod LODs.....
> 
> I'm flattered that they sent them, just wouldn't mind knowing what for? I have sent an e-mail but no response yet so thought I'd ask the people in the know
> 
> Wonder if I'll tell any difference between the OPA637BP's and AM's? There is a difference between the OPA2111KP and AM's so I'm hopefull....


 


 Could be for a few things...perhaps they were added by mistake.  I noticed a difference between the AU and SM modules I have,  You can usually notice differences between chip and TO-99 opamps.
  Enjoy.


----------



## murrays

Quote: 





leeperry said:


> one thing really not clear to me is that 1028A was making static
> pops when my bathroom neon turned off or my fridge turned on...and
> this doesn't happen whatsoever on OPA2604/AD845/LT1363, so much for PSRR?! maybe coz 1028 is a negative feedback opamp?
> 
> my HD2 soundcard was also making nasty pops in the very same situations..the mysteries of audio


 
  That's more likely picking up RF (EMI), not really anything to do with PSRR. PSRR only relates to signals appearing on the opamp's PS pins.  RF could be getting in anywhere. Is your circuit fully enclosed in a metal case? Is it running off batteries or mains?  The opamap could be oscillating at a MHz frequency, which will intermodulate with other external RF to produce audio noise (that's how an AM radio works).
  I have built an instrumentation amplifier with the LT1028 and found that it needed several remedies and fine tuning to keep it stable. Adding a small overcompensation capacitor on pin 5 certainly helps (see the datasheet) .  When not in its aluminium box it would pick up all sorts of hash, even just waving a hand near it.


----------



## leeperry

Thanks for the reply Murray! Well, I ran it in its own faraday cage from a linear regulated DPS, and toslink from the computer:
   


 


   
  this DAC also runs on a virtual ground layout if that matters.
   
  that's the inside of the PSU(w/ the top gray 220V transformer): http://www.head-fi.org/forum/thread/286131/diy-supply-for-firestone-spitfire#post3664105
   
  waving an hand at it would create audio artifacts???? wow, how come it's so pricey if it's so pesky 
	

	
	
		
		

		
		
	


	



   
  indeed when I got an audio repair guy to check for oscillation, he told me that my LT1028AC were very very slightly oscillating in the MHz range...so you're saying that the opamp was unstable and that the noise on my house electricity circuit induced by the neon ballast/fridge motor was making it go "berserk"?
   
  many active speakers and pro audio/music gear are known to "glitch up" when a fridge turns on/off, most home studio enthusiasts are forced to get a dedicated line off their counter...and I thought that my bathroom neon ballast was at fault 
	

	
	
		
		

		
		
	


	



   
  bottom line is: I can use the bathroom neon test to check for oscillation


----------



## murrays

Quote: 





leeperry said:


> waving an hand at it would create audio artifacts???? wow, how come it's so pricey if it's so pesky
> 
> 
> 
> ...


 
   
  It's not that some expensive opamps are "pesky" (in a faulty way) - you must realise they are doing what they were designed to do and that includes "working" at up to MHz frequencies.  The circuit looks very different to RF: capacitances and stray couplings really start to matter.  The chip doesn't know that it is supposed to do a good job with audio (which is all you are wanting), it just tries to process all inputs in its range.  That's where bypass and compensation caacitors are used to influence the HF behaviour.
   
  It would seem fridges are particularly bad for interference. When the motor switches on there is a big initial surge due to the load of the compressor. This causes power spikes and radiation of EMI, which may not all get caught by mains filters. 
   
  As to your soldering: yes, I saw the high res photos you posted and some of that 3 AM soldering didn't look too good, maybe a dry joint on one corner.  Good job you fixed it. A good solder joint will have a smooth fillet where the solder has flowed as it bonds.  Any lines or marks that look like cracks are to be suspected.


----------



## leeperry

the fridge is very far from my DAC, how could EMI's reach it in its faraday cage? it's definitely something that goes through the shared house electricity circuit IMHO, reason why home studio ppl are usually forced to get a dedicated line off their counter so it won't be shared w/ their fridge anymore(they also get a dreadful glitch when their fridge turns on/off)
   
  I think the ballast/motor just inject a lot of interferences in the shared house circuit...and for whatever reason -even though it runs on a linear regulated DPS!- LT1028 glitches up...due to oscillation in the first place then?


----------



## murrays

Quote: 





leeperry said:


> waving an hand at it would create audio artifacts???? wow, how come it's so pricey if it's so pesky


 

 Just to set the record straight, the LT1028 was being used as an instrumentation amplifier at x10 and x100 to measure down to the noise floor (of a headphone amp) on the oscilloscope. That went down to a resolution of about 10 micro-volts, so I could see all sorts of bad things happening.  This was what I wanted, as I was tracking down sources of annoying low-level interference.  The LT1028 just happened to be the best low-noise opamp I had to hand, but I can't comment on its audio in this implementation.  Adding a small value (< 100 pF??) ceramic on pin 5 definitely improved the stability of the circuit, hopefully without too much VHF rolloff.  The pin 5 option is not standard, it is a customisation for this chip.  There is a graph in the datasheet showing useful ranges, but I experimented to get a happy outcome (can't recall the exact value).


----------



## leeperry

Hehe ok, you nailed several times that LT1028 couldn't be rolled blindly...you were spot-on!
   
  One thing's for sure, I'll never use opamps on anything else than a linear regulated DPS together w/ a galvanically isolated connection to the computer anymore, it just sounds too good 
	

	
	
		
		

		
		
	


	



   
  I've also added clipsable ferrites on the cable between the DPS and the DAC and on each end of the DPS power cable...superstition I guess, but my neighbors are flooding me w/ wifi


----------



## SpudHarris

Here is the reply I got from the seller of my OPA637's who kindly dropped in a couple of electrlytic caps (tiny nichicons).
   
_''your gonna use them on +Vs, -Vs pins. yes polarity matter use + with + and - w/ -. So on +Vs you'll have positive end of cap connected to it and negative to ground. for -Vs you'll have positive end of cap to ground''_
   
  So I assume this is right?
   

   
   
  But what will it achieve?


----------



## ROBSCIX

They are for bypassing, they are usually added on high speed opamps to help with stability.  Other use them for audio designs to help prevent noise on the power supply.  Many opamps can be very sensitive to any noise on the power pins.


----------



## SpudHarris

And after all that.................. It doesn't fit inside my Fi-Quest anyhow. You gotta laugh 
	

	
	
		
		

		
		
	


	



   
  And the OCD continues on the DIY cable thread also. Yes, Leeperry I'm talkin' to you hehe..... 
	

	
	
		
		

		
		
	


	




 Where do we put a stop to our search for the perfect sound??


----------



## Mad Max




----------



## leeperry

OCD? not really 
	

	
	
		
		

		
		
	


	



   
  I'm dead on 1363CS8 atm, it does everything I want to hear. I've got AD8597 and AD825 on the waiting list, coz I just like the moment after you've soldered them to pop them in and look for SQ differences/improvements 
	

	
	
		
		

		
		
	


	



   
  but cables change the sound as much as opamps, yes...they do, they really do


----------



## K3cT

Quote: 





mad max said:


>


 

 Cheat like me and get a discrete amplifier. 
   
  I've sold off everything I had with the exception of the ADA4627-1, AD797 and AD8597.


----------



## SpudHarris

AD8597?? Never used this...... Any good?


----------



## leeperry

spudharris said:


> AD8597??


 
   
http://www.head-fi.org/forum/thread/432749/the-opamp-thread/930#post_6041278


----------



## K3cT

Quote: 





spudharris said:


> AD8597?? Never used this...... Any good?


 

 I like it as it sounds like a "funner" AD797.


----------



## ROBSCIX

Quote: 





spudharris said:


> And after all that.................. It doesn't fit inside my Fi-Quest anyhow. You gotta laugh
> 
> 
> 
> ...


 

 Can you use an extension cable?  Not ideal but it may work.  Why would you ever want to stop looking for your personal "perfect" sound?


----------



## SpudHarris

Quote: 





k3ct said:


> I like it as it sounds like a "funner" AD797.


 
   
  Well I like the sound of that for sure. I usually get my opamps from Farnell but they are only showing US stock (£16 delivery charge).
   
  Anyone have a couple of them to trade??? I have a few different opamps here. Failing that I'll buy if anyone has any spare, pleeeeeeeeeease. I need another fix and a funner AD797 sounds like just the job


----------



## Apocalypsee

I would like to ask, can the LT1364 runs from single positive voltage, or higher positive voltage than negative one? Because I felt that ~5V on this opamp don't do it any justice and I think higher voltage would definitely make it sound better, any thought? Planning to feed it through single +17V linear PSU and see how does it sound


----------



## ROBSCIX

@Spudharris, are you losing your love for the OPA2111AM's?


----------



## SpudHarris

Haha, funny you should ask that.......
   
  I have been using OPA637AM's in my Fi-Quest Headphone amp. It's set up with 4 stacked BUF634's and has an option of 2 or 4 channel mode. Unfortunately with the 637's (which are astoundingly good) I can't use with low impedance phone and even with my 600ohm DT880's I can't use high current mode 
   
  I've swapped back to the OPA2111AM which suits all my phones and is IMHO not a million miles from the OPA637 in terms of SQ, also the high current mode which can be used with this chip adds a little more to the SQ.
   
  So no still lovin' the OPA2111AM  What about you?


----------



## ROBSCIX

Yes, still a great amp.  I sent one to a buddy also and he started using it in his sources.


----------



## SpudHarris

I assume I'm not on my own by saying this...... Every once in a while everything is just soooooooooooooo right you could listen forever 
   
  Last night whilst desparately trying once again to love my DT880/600's I swapped out the OPA637's in my Fi-Quest and dropped in some AD797BRZ's (been a while since I've tried these) and Oh my God everything just clicked and the hairs on my neck stood on end many time during the evening.
   
  I paid quite a lot of money for the DT880's as the manufaktur route was the only way I could get the 600ohm version. I had to wait a long time for them to be made so the expectation was high especially since I've been following the appreciation thread. When they got here a couple of weeks back I was slightly dissapointed that they didn't set me alight immediately and I've been trying to love them every night since. Well thanks to the AD797's I can honestly say I'm in love..........
   
  Is there a higher grade AD797 than BRZ? I can get these from a reputable seller are they a higher grade? Anyone know?
   
  Cheers
   
  Nigel


----------



## leeperry

BN is no higher grade than BRZ...it's not lead free that's all. Did you roll LT1363CS8? this is the true king of PRaT to my ears...but its PSRR is low so it needs a clean PSU and at least ±12V to really sing


----------



## SpudHarris

I have those but, no i haven't tried them in the Fi-Quest. Cheers for that, tomorrow is LT1363 day


----------



## leeperry

You can literally hear the very high speed of LT1363CS8, and the sound is very percussive...especially the low end bass


----------



## morfic

Quote: 





leeperry said:


> You can literally hear the very high speed of LT1363CS8, and the sound is very percussive...especially the low end bass


 

 You HEAR the SPEED of the OPAMP? Seriously? What does speed sound like?


----------



## leeperry

morfic said:


> You HEAR the SPEED of the OPAMP? Seriously? What does speed sound like?


 
   
  It picks up every minute detail slower opamps only wish they could present you with, this guy tried to put it in words: http://www.head-fi.org/forum/thread/89813/lt1363-opamp#post_1042510
   
  When I roll slower opamps, I'm usually bored after a few mins....w/ LT1363 my phone is the bottleneck, w/ slower opamps they are the bottleneck


----------



## morfic

Quote: 





leeperry said:


> It picks up every minute detail slower opamps only wish they could present you with, this guy tried to put it in words: http://www.head-fi.org/forum/thread/89813/lt1363-opamp#post_1042510
> 
> When I roll slower opamps, I'm usually bored after a few mins....w/ LT1363 my phone is the bottleneck, w/ slower opamps they are the bottleneck


 
   
  Where does "fast" start? OPA627?
   
  About the LT1363: have you checked your DC offset lately? I don't know what you use it in, so if you are not so lucky, it might pass you on a little present.
  Compare input bias current of something sane like the LME49710 (55MHz is still fast for you, no?) with that of the LT1363.
   
  Point i am trying to make is not every opamp is a good match for a circuit that was not made for it.
   
  If the 55MHz of the LME49710 is not fast enough for you, then you surely are a LM6171 candidate.


----------



## leeperry

my DAC has decoupling caps, I get a steady 0.3mVDC from the LT1363(used as PCM1793 LPF).
   
  well, it's not about Gain-Bandwidth, it's about Slew Rate....1000V/µs on the 1363


----------



## morfic

I knew it, the LM6171 is right up your alley.


----------



## leeperry

morfic said:


> I knew it, the LM6171 is right up your alley.


   
  Thanks for the tip, I'll be sure to look into it(and report back)


----------



## ROBSCIX

LOL, I can hear the speed! 
   
  GO and do some reading so you can properly understand slowrate and opamp speed.


----------



## Pacha

I can hear the speed of the cars in a race through any opamp so everything is fine lol 
	

	
	
		
		

		
		
	


	



   
  What's the point with the actual speed hearing about opamps? What is to be heard, if anything has to be?


----------



## leeperry

details retrieval, slow opamps only wish they could pick up as many details as 1363.
   
  1364(its dual counterpart) is successfully used in many commercial DAC's: http://luckyfrogaudio.co.uk/poppulse_uii_dac.html


----------



## majkel

Speed contest? I used once the AD8000 in a low voltage headphone amp as the rail splitter. Look at the slew rate and the bandwidth. Can you beat this?


----------



## leeperry

well, Slash47 who's also a big fan of 1363 didn't like LM6171..I'm still eager to try AD8597 AD825 and LM6171 
   
  I've got LT1115, LT1468, OPA827, OPA132U and a few others waiting to be tried (again) but so far LT1028 is too pesky, oscillates like hell and its SS is really narrow....I like the bass, though! but 1363 has much less bloated bass IME and much wider SS.


----------



## Mad Max

1028 oscillates like hell now?


----------



## leeperry

well, it'd appear that the glitches I get when my bathroom neon's turned off are due to its oscillation yes 
	

	
	
		
		

		
		
	


	



   
  1363 does everything 1028 does, just better.


----------



## Mad Max

Perhaps a linear, regulated dps makes that much of a difference, because in my gear, 1028 does everything better except detail. But 1028 has that funky distortion to its sound that I have never heard in anything. What do you call it again?


----------



## leeperry

I don't really see what you're talking about?
   
  Also a friend of mine has had troubles w/ AD797BR in his Zero DAC, after a few mins the chips are so hot that he cannot touch them...again, blind opamp rolling is not such a good idea


----------



## Mad Max

It's at the end of the sounds, like "artificial detail" or something. But then you realize it isn't detail, just a lack of it. With 1363, I hear much better how notes are articulated and what not, giving a more natural sounding presentation to a degree.


----------



## buz

As my payments to audjade seem to get routed to nirvana (and then come back when I reclaim them, quite the zombie money  ) I am wondering if I should instead try and buy from this guy (who offers two sets for nearly the same price), anyone got any experience:
  http://cgi.ebay.ch/Dual-Mono-Opamp-OPA2604-NE5532-TL072-AD797BR-/320500739352?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item4a9f552d18


----------



## Mad Max

So little feedback... =\


----------



## buz

Yeah, that's usually the problem with the cheap Chinese sources. I'd try him, but I have no known good AD797 to compare with


----------



## leeperry

they have tons of non-"Z" AD parts in China...they're not allowed to use them in new builds, so they prolly get them for 1 cent a pop at the market 
	

	
	
		
		

		
			




   
  I've often bought non-"Z" AD opamps from China, as far as I can tell they were not fake.
   
  What I would be more worried about is the adapters they used, as I tried those and they sounded horrid compared to the good ole' Browndog w/ LT1363CS8(very bright/harsh..possibly oscillating?): http://cgi.ebay.com/4-set-SOIC-to-DIP-8-pin-Convert-PCB-Adapter-SMD-OPA627-/230408619844
   
  and also, the old version of this one had soldered pins: *http://cimarrontechnology.com/so8to8-pindipadapterpn970601-3.aspx*
   
  but this one doesn't...I've noticed a clear SQ improvement when soldering the pins on both sides of the PCB: http://www.audioupgrades.co.uk/images/browndog/020302topbot.jpg


----------



## buz

Somehow that doesn't make too much sense - is the contact perhaps not entirely stable without the soldered pins?


----------



## leeperry

well, that's the old browndog w/ soldered pins:



   
  why doesn't he do it on the singles>dual adapters? to save 1 cent per adapter?
   
  when soldering the pins on a singles>dual SOIC8>DIP8 I've heard the same improvement as when I went from singles DIP8 on a browndog+sockets to the same chips soldered directly onto the browndog. Soldered joints do matter for opamps...especially on adapters apparently.


----------



## Spacehead

I built a special cmoy with balanced inputs, breadboard and SMD. The virtual ground is buffered by two OPA2613 in parallel, so 4 amplifiers in the ground, total max current about 1 A 
   
  I put a LT1364 in to it. I guess the sound is pretty good, AD8397 is a little better, smoother. LT1364 can drive my headphones very well without much distortion. 
   
  The op amps usually don't sound so good without buffers. I can try which op amp sounds best in this circuit. It is pretty fun. ADA4899-1 didn't sound too good, little harsh. 
   
  I could try LM6172 next.


----------



## leeperry

I present you the browndog w/ soldered pins: 


   
  I didn't like the sound of this chip, though...not percussive enough, hard to explain.


----------



## Mad Max

Too soft on attack?
   
  Edit: LT1469IS8 - yeah, like it is a bit soft on percussion attack or something. I kind of don't like that about it either. Not bad at all otherwise.


----------



## Spacehead

I have OPA637AU for sale! 
   
http://www.head-fi.org/forum/thread/493758/fs-genuine-opa637au-10-pieces-eu


----------



## ROBSCIX

How did you get so many?  Mass order for good price?


----------



## Spacehead

that is right. 
  
  Quote: 





robscix said:


> How did you get so many?  Mass order for good price?


----------



## Mad Max

EL2125 - this one sounds exceptionally clean in the Compass, quite possibly the cleanest as far as my collection. Not the most nuanced, yet not as polite as LT1028 and Earth, and treble extension is real nice, second only to 4627-1B. It is a slight touch laid-back in the mids with a very tight sound all throughout and sounds a bit like LT1357 & LT1363, tonally.
   
  I'm not sure, but I think I overlooked 4627-1B's treble somewhat. This opamp has the best treble, whether it is used in the Compass DAC or Minibox-E+, 4627-1B's sky-reaching treble has better presence than any other opamp I've tried so far. The Compass adds wonderful fullness to 4627-1B's treble that none of the other opamps can match.


----------



## Spacehead

For those who would like to try OPA637 but don't want to solder, I would like to offer a pair , either on a single to dual op amp adapter (browndog) or on dip8 sockets.
  Please PM me.


----------



## jageur272

I'm looking to upgrade from an OPA2134 (mmm... Nice slow sound and muddy bloated bass!) and I've been going through this thread a bit.  Is there a good source for the LM6172 or the LT1364?  I'd much rather not buy from one of the Chinese ebay sellers as I'm quite wary of fakes, but if there is a reputable Chinese source, I'd be more than willing to buy from them.


----------



## Yoga Flame

Digikey.com and Newark.com have them. They are worthwhile if you happen to need to get other parts as well since it's flat rate shipping. (Digikey is, at least. They UPSed me my order the next day for $8 here in Canada.) Mouser.com is good too, if you are looking for Texas Instrument chips.
   
  Also, there's someone over at the FS forums who's been looking to sell his LT1364 for some time now.
  http://www.head-fi.org/forum/thread/478229/fs-lt1364-and-lme49720-op-amp
   
  Or you could take Spacehead up on his OPA637 offer.


----------



## jageur272

Thanks for pointing out that thread Yoga Flame, somehow I didn't see it.

 I order from mouser and digikey fairly often, but ordering small quantities from them just kills shipping wise (and I just ordered a substantial amount of parts last week, no new orders anytime soon).
   
  I would grab a pair of 637's, but unfortunately I need a dual opamp as there isn't space for a single to dual adapter.


----------



## leeperry

so many empty mouths to feed, and so little motivation to do so: 


   
  I'll start by AD797BR, then LM6171 and AD8597


----------



## SpudHarris

Haha, Lee you have more of those than I do and I'm crazy obcessed...... I like the ones under the Brown Dogs (DIY Link?) I assume you got them of the bay like I do, they are good quality don't you think? Gold pin headers too which is nice.


----------



## leeperry

Well, I've tried them w/ LT1363CS8 and it made them bass shy and utterly bright...I think the commercial bs on his ebay page dissing the genuine Browndogs is completely unfounded...Also, the presoldered pads hardly stick w/ Cardas eutectic solder...these adapters have disgusted me of soldering opamps tbh. And it's also quite annoying to solder the adapter pins, even though I also do it on the real browndogs now for improved contact as it made a clear audible improvement on LT1363CS8 for me(clearer center channel).
   
  BTW, you never told me what you honesty thought of LT1363CS8? But I'll try AD797BR on a real browndog anytime soon, I'm starting to realize that most cheapo adapters from ebay end up being bass shy...for some reason.
   
  I really don't like ADA4627-1A(never been a fan of the OPA_27 sound) and LT1028AC is too pesky, I give up...1363 sounds perfect to my ears anyway


----------



## tamu

Spudharris I sent you a pm..


----------



## leeperry

alright, AD797BR on a genuine browndog is..........beyond words! 
	

	
	
		
		

		
		
	


	




 What's amazing on this chip is the SS depth, how can stereo audio get so 3D? It picks up anything that's on the record and that your source allows to get through....it's anything but a bottleneck, good god! trumpet sounds so holographic on this chip, and the low end percussion is more natural than LT1363CS8 I think...but still very loud and punchy, and the SS seems to have an infinite number of layers and slices hah
	

	
	
		
		

		
		
	


	



   
*PS:* PRaT is lower than 1363 I think, but the SS is far clearer and the trebles far less colored...still, PRaT is lower. It sounds far more analytical and much less "fun"...I'll solder AD8597 tomorrow 
	

	
	
		
		

		
		
	


	



   
*PPS:* yeah, not as percussive or "funky" as 1363....roll back in progress. I'm bored when I listen to 797B. 1363 is so full of emotions on well recorded vocals and Fender Rhodes that it could almost put you in tears...I can't believe how good this chip sounds


----------



## SpudHarris

Quote: 





tamu said:


> Spudharris I sent you a pm..


 


 Thanks Tom, I did get it but can't use it I'm afraid. Thank you for thinking of me though


----------



## dark1evil2

whats the best Opamp for Xonar Essence ST ?


----------



## tamu

hey guys I have a browndog adapter that I dont need(seller sent the wrong item).

  does anyone in UK-Eu needs it? I can send it for free..


----------



## leeperry

hehe, I thought my chinese AD797BR didn't look new..the seller just told me that they've been desoldered "_from a electrocardiograph by special too_l"...I guess they must be burned-in well, and possibly saved some lives too


----------



## Mad Max

Quote: 





leeperry said:


> *Well, I've tried them w/ LT1363CS8 and it made them bass shy and utterly bright*...I think the commercial bs on his ebay page dissing the genuine Browndogs is completely unfounded...Also, the presoldered pads hardly stick w/ Cardas eutectic solder...these adapters have disgusted me of soldering opamps tbh. And it's also quite annoying to solder the adapter pins, even though I also do it on the real browndogs now for improved contact as it made a clear audible improvement on LT1363CS8 for me(clearer center channel).
> 
> BTW, you never told me what you honesty thought of LT1363CS8? But I'll try AD797BR on a real browndog anytime soon, I'm starting to realize that most cheapo adapters from ebay end up being bass shy...for some reason.
> 
> I really don't like ADA4627-1A(never been a fan of the OPA_27 sound) and LT1028AC is too pesky, I give up...1363 sounds perfect to my ears anyway


 

 Are you sure you soldered 1363 correctly?


----------



## Mad Max

Quote: 





dark1evil2 said:


> whats the best Opamp for Xonar Essence ST ?


 

 Depends. Have you checked the Xonar Essence STX thread? I'm pretty sure that is discussed and rediscussed until your ears eyes bleed, lol.


----------



## leeperry

mad max said:


> Are you sure you soldered 1363 correctly?


 

 AD797BR on a real browndog sounds much more bassy than on those presoldered ebay units...adapters do matter IMO.


----------



## dark1evil2

Quote: 





mad max said:


> Depends. Have you checked the Xonar Essence STX thread? I'm pretty sure that is discussed and rediscussed until your ears eyes bleed, lol.


 


 yeah but theres so many i've read several pages and now i have a headache lol
   
  will 1 LME49720NA 2 AD8620AR be good choice
   
  im using this headphone's if it help  ad700 & soon will get dt990


----------



## Mad Max

Quote: 





dark1evil2 said:


> yeah but theres so many i've read several pages and now i have a headache lol
> 
> will 1 LME49720NA 2 AD8620AR be good choice
> 
> im using this headphone's if it help  ad700 & soon will get dt990


 

 I guess.  8620/8610 is kind of mediocre, try OPA1642/1641 instead.  Also consider ISL28127 - it is very refined and the clean I've heard and isn't as sensitive to dirty power as a lot other opamps.  My favorite, ADA4627-1B, might be one of your best choices.  It seems to be good even in a soundcard.  Whether you like it or not will depend on whether or not you like the voice of PCM1794(?).
  .
   
   
  Quote: 





spacehead said:


> There is good amount of details
> 
> I have ADA4627-1BRZ (x2) on X-FI
> 
> ...


 

  
   
   
  Quote: 





leeperry said:


> AD797BR on a real browndog sounds much more bassy than on those presoldered ebay units...adapters do matter IMO.


 

 I'm not using presoldered ones. I'm using the unassembled ones with thicker traces and pins.


----------



## leeperry

mad max said:


> I'm not using presoldered ones. I'm using the unassembled ones with thicker traces and pins.


 

 Maybe that's why you find 1357/1363 to sound the same? these diyinhk adapters sound horrid to me, and nothing beats 1363 on a real browndog to my ears...it plays music exactly the way I want to hear it! but I'll try LM6171 later today I think, I'm addicted to speed and everything seems slooooooooooow compared to 1363(Slash47's fav opamp and a former favorite of Andrea), LM6171 might change that.


----------



## Yoga Flame

leeperry, is that the same LT1363 that you tried on both types of adapters? Apart from soldering defects on the adapter, it is surprising to me that an adapter would make a big difference to the sound.


----------



## leeperry

These were LT1363CS8's from the same batch, and I've noticed the same diff. w/ AD797BR...it's always sounded bass shy on those presoldered ebay adapters, but sounds as bassy as can be on a genuine browndog.
   
  adapters matter a lot, as this guy's commercial bs tries to prove: http://cgi.ebay.com/10pcs-Dual-SOIC-to-DIP-8-Convert-PCB-Adapter-SMD-OPA627-/230379640581


----------



## Mad Max

I still think you messed up somewhere.


----------



## 12Bass

Finally had a chance to listen to the OPA228 and made a comparison with OPA211.  In my application, I'm hearing perhaps a somewhat thinner, though more open, sound than the OPA211.  The OPA211 may have a bit more fullness in the lows, while the upper-midrange/treble region is more aggressive as well.  OPA228 might sound less "effected".  Still not sure which I prefer.  Both are decent chips, IMO.


----------



## 12Bass

Also did another comparison between OPA211 and OPA1611.  Their specifications are extremely close, so much so that it appears that the OPA1611 may just be a rebadged OPA211 which is marketed for audio applications.  However, after several A/Bs, there was a noticeable difference between the two.  Although their basic tonalities are very similar, the OPA1611 just doesn't seem to have the same clarity as the OPA211... sort of more "bland" sounding.
   
  Did a little more listening to the OPA827 during the same session.  I get the impression that it has a bit more coloration than the bipolars, though it is a euphonious coloration, IMO.  It seems sound fat in the bass, pleasing in the midrange, and smooth in the highs, without the "edge" of some other parts.  It is pretty detailed for a FET device, but appears to lose a little resolution compared to the better bipolar op amps.


----------



## leeperry

mad max said:


> I still think you messed up somewhere.


 

 Well, goodie for you 
	

	
	
		
		

		
			




   
  I use cardas eutectic solder and a 30W sharp iron, I've never burned a single chip. OTOH, LT1028CS8 and ACN8 sounded *way* different for me on browndogs, Andrea told me they didn't for him.
   
  One thing I know is that AD797BR and LT1363CS8 sound bass shy for me on non-genuine browndogs...You said you don't like 1363 but you did put it on a diyinhk adapter, maybe it's about time you start evaluating this chip properly 
	

	
	
		
		

		
		
	


	



   
  OPA1611 sounded terrible to my ears..just like OPA211/827(and ADA4627-1A for that matter 
	

	
	
		
		

		
		
	


	




)


----------



## 12Bass

Quote: 





leeperry said:


> OPA1611 sounded terrible to my ears..just like OPA211/827(and ADA4627-1A for that matter
> 
> 
> 
> ...


 

 Mind to say why you think they sound terrible?  To my ears, the OP211 and OPA827 have pretty different tonalities. Will be trying the AD797 again soon to see if my impressions might change. 
   
  Haven't tried ADA4627-1.  ADA4898-1 didn't wow me; however, looking at the data sheet, it may take an optimized circuit for it to perform as designed (very low impedance).


----------



## leeperry

OPA211 sounded like something was really going terribly wrong, as majkel said: http://www.head-fi.org/forums/f6/audio-gd-discrete-op-amps-reviewed-OPA-earth-OPA-moon-OPA-sun-v-2-a-397691/


> The increased shape detail and huge soundstage is probably the result of something I'd call sound disassembling. It's like losing spatial coherence of each sound, having the tone in one place, and the harmonics just aside, not surrounding the right tone. Strange but true.


 
   
  I really hated listening to this chip...and well, OPA827/ADA4627-1A just don't do it for me...really not the sound I'm looking for, it's hard to explain. ADA4627-1A had some kind of very colored bass and "plasticky" mids, to me all those chips have "BB" written all over them...and that's really not hifi to my ears.


----------



## 12Bass

After some consideration, I may agree somewhat with majkel about the OPA211.  Not sure, but it almost seems as if the frequency spectrum is not entirely continuous, as if there's something missing between the midrange and the treble.  In comparison, the OPA827 sounds more "connected", though less "impactful".  I like what it does with my basses.... warm, yet detailed.


----------



## SpudHarris

I'm not actively rolling at present as I seem to have found my perfect match for both my Fi-Quest and my P3+.
   
  Fi-Quest is running with metal can OPA637's and 4 x stacked buffers and the P3+ has a metal can OPA2111 with 2 x stacked buffers and OPA627's in G/VG.
   
  My new venture is to find my perfect match in Tubes for my new Woo Audio 6  
	

	
	
		
		

		
		
	


	




. I'm monitering this thread for the next best thing in Opamps to appear but until then I'll be lurking and rolling Tubes......


----------



## majkel

I'm curious how much better are the metal can versions than DIPs, especially regarding the OPA2111, OPA627 and OPA637? Even compared to the OPA827AID, the OPA637AP sounds rather poor. I went back to the op amp topic as I modify from time to time Lehmann Black Cube Linear like amps. I had the best results with the OPA2228, the AD8599 being second best. I also found it to be no advantage to have two OPA228 pieces. The soundstage is more dual mono, but imaging is less coherent, with lesser focus. I no more support the offset pin biasing trick as adding some good bipolar and film capacitors between supply rails gives better results without such "cheating". The trick actually sounded a bit fake on the AKG K 701. Grado PS1000 accepted it well, making some advantage of the smearing effect on these edgy headphones.


----------



## SpudHarris

To my ears the OPA2111AM was a lot nicer all round than the KP version. With the OPA637AM's I'd like to say they were a million times better than the BP's but to be truthful I think they only just better them and even that could be placebo because they ARE ''Metal Can'' and have ''Gold Pins'' who knows?
   
  My opinions regarding rolling have mellowed recently due to being happy for once with the results I have. Only thing is, I now have loads of tubes on route from all over the world for rolling haha....


----------



## leeperry

Last time I tried tubes I quickly got to understand why opamps superseded them, hah 
	

	
	
		
		

		
		
	


	



   


12bass said:


> I like what it does with my basses.... warm, yet detailed.


 
   
  tried LT1028ACN8/LT1363CS8/AD797B? their bass is top-notch, 1028's bass is louder/more flabby IME, 797B's a bit too analytical but 1363CS8's is the perfect in-between...I'm so glad that my opampitis is finally cured(for now heh), and 1363 needs a clean PSU due to its lowish PSRR. BB can only dream about reaching the SQ of the 3 aforementioned chips...the PCM1794 datasheet advises to use LT1028 as LPF for a good reason.


----------



## Apocalypsee

LT1364 is a great opamp, it work virtually anywhere, and sound great anywhere as well. Tried it on old SB Live! 5.1 soundcard, it sound excellent. Tried on X-Fi Elite Pro, sounds awesome as well. Used it on X-Fi Surround 5.1 USB which use only single 5V supply, LM4562 sounds terrible with lots of sibilance and harsh treble but LT1364 just shine


----------



## leeperry

Ditto! and 1364 is only slightly worse than 2*1363 on a browndog...some commercial DAC's run it stock: http://www.google.com/search?hl=en&q=poppulse+lt1364c
   
  It must be quite a shock for non-rollers to have such a good sounding chip in a commercial unit 
	

	
	
		
		

		
		
	


	



   
http://www.tnt-audio.com/sorgenti/usb_dac_shootout_e.html


> Right from the off, the SuperPro is impressive. Impressive in the amount of fine detail it produces. Its sound is bright and sparkly (but certainly not over so). Detail retrieval is very good and it does that 'layers' thing where you get a very good range of tone. It's musical, and grabs the attention. Sound-stage is large and imaging very clear.


----------



## Spacehead

Quote: 





apocalypsee said:


> LT1364 is a great opamp, it work virtually anywhere, and sound great anywhere as well. Tried it on old SB Live! 5.1 soundcard, it sound excellent. Tried on X-Fi Elite Pro, sounds awesome as well. Used it on X-Fi Surround 5.1 USB which use only single 5V supply, LM4562 sounds terrible with lots of sibilance and harsh treble but LT1364 just shine


 

 Nice! I have LT1364 also on my Sound Blaster X-FI. It is excellent, clean, accurate, musical op amp!


----------



## Mad Max

1363 is not bass-shy in my gear, also its lack of articulation has been bugging me.
  
  Quote: 





12bass said:


> ...
> Haven't tried ADA4627-1.  ADA4898-1 didn't wow me; however, looking at the data sheet, it may take an optimized circuit for it to perform as designed (very low impedance).


 

 Give 4627-1 a try, You may have better luck with it than somebody.


----------



## Mad Max

*double post*


----------



## leeperry

1363 was sounding way too colored on my Prodigy HD2 as final buffer..hard to bear for more than a few hours. It works better as DAC LPF and from a clean PSU(due to its low PSRR), and also on a genuine browndog....but when it does, oh my oh my


----------



## G.Trenchev

Just got my OPA2134's.Impressions:
  -Almost no tonal difference to NE5534
  -Better separation and detail
  -Brighter highs
  -Soundstage a bit wider
   
  Much better overall,but not as much as the price(5 times more expensive vs two NE5534)
  Ordered OPA134 on sunday


----------



## ROBSCIX

Quote: 





g.trenchev said:


> Just got my OPA2134's.Impressions:
> -Almost no tonal difference to NE5534
> -Better separation and detail
> -Brighter highs
> ...


 

 Either of those opamps are considered cheap from a price standpoint.  The 5532 is one of the cheapest so 5 times more is still not that much.


----------



## G.Trenchev

OK,anybody else finding OPA2134 too warm ?


----------



## Spacehead

Quote: 





g.trenchev said:


> OK,anybody else finding OPA2134 too warm ?


 

 It is loose smooth and warm. How you would like it to sound?


----------



## G.Trenchev

Well,I'm not sure really...I really like the slow,loose and detailed sound(that's what I wanted).It is great for classic and jazz.I just find the bass too warm and sweet to my taste.It has great punch and detail,but I would like more "metallic" feeling.


----------



## leeperry

those 2/134 chips are a waste of time and money...some guidelines on the chips to try: http://www.head-fi.org/forums/f6/audio-gd-discrete-op-amps-reviewed-OPA-earth-OPA-moon-OPA-sun-v-2-a-397691/
   
  the highest grade of the 132/134 family is OPA132U, try that instead...if you really must


----------



## ROBSCIX

Quote: 





g.trenchev said:


> Well,I'm not sure really...I really like the slow,loose and detailed sound(that's what I wanted).It is great for classic and jazz.I just find the bass too warm and sweet to my taste.It has great punch and detail,but I would like more "metallic" feeling.


 

 The OPA2134 have what people call the "Burr Brown" sound. sonic traits that come through on alomt all units from the burr brown line up.
  Try the OPA2107....It may give you what you are after.


----------



## 12Bass

Or maybe OPA2604?
   
  Personally, I don't find the newer TI/BB parts (OPA211/1611/827/1641) to sound much like the older ones (OPA132/34/604).


----------



## G.Trenchev

Thanks,I'll try these.
  No urgent need actually,I got into BB sound and I like it now.While 5534 was very neutral-even amping an amp with the amp adds nothing to the sound(it's "invisible"),it was somewhat compressed sounding.2134 is open and warm,musical.Somehow it retrieves the details and adds a warm touch.It's a true Hi-Fi opamp,but it's not neutral,you can always tell it's there by the significant sound signature.I thought It won't do rock,but I was wrong.It molds perfectly with DP's Motorhead,sounding very fun and energetic.Also great for classical and jazz.That's it.
  I can spend a night rolling opamps,and there's so many.Great hobby


----------



## Mad Max

I think you'll love 1611 and 1641.
   
  My favorite BB so far is THS4081.


----------



## leeperry

did some more rolling
	

	
	
		
		

		
		
	


	



   
  -LM6171AIM: very very close to 1363, just less percussive and more boring
   
  -AD825: the same harsh/metallic/agressive upper mids as AD845...worthless!
   
  -LT1115: the SS is clearly different from 1028AC, and it's also far less bassy...but 1363 has more precise/tighter low end bass.
   
  now comparing 1363CS8 and 1363CN8 
	

	
	
		
		

		
		
	


	



   
*PS:* on this song(in FLAC), 1363 puts the other chips to shame: http://www.google.com/search?q=Big%20Bang%20-%20Speak%20Low&tbs=vid:1


----------



## ROBSCIX

Quote: 





g.trenchev said:


> Thanks,I'll try these.
> No urgent need actually,I got into BB sound and I like it now.While 5534 was very neutral-even amping an amp with the amp adds nothing to the sound(it's "invisible"),it was somewhat compressed sounding.2134 is open and warm,musical.Somehow it retrieves the details and adds a warm touch.It's a true Hi-Fi opamp,but it's not neutral,you can always tell it's there by the significant sound signature.I thought It won't do rock,but I was wrong.It molds perfectly with DP's Motorhead,sounding very fun and energetic.Also great for classical and jazz.That's it.
> I can spend a night rolling opamps,and there's so many.Great hobby


 
   
  There are many aorudn here that do this as a hobby, some been in this much longer then others.  When you change out an opamp just remember to give yourself a chance to get used to the new signatures.  There are much better opamps out there then the OPA2134 but it is a resonable place to start...  Have fun.


----------



## leeperry

just because ceramic is audiophile grade as we all know:
   


   
	

   
   
  I thought I'd use a big copper heatsink, but ceramic is immune to EMI/RFI...I like that 
	

	
	
		
		

		
			




   
  and the 1363 datasheet gives better thermal specs for CS8 over CN8, I'll check tomorrow how temperature goes..they were slightly warmer than my finger w/o cooling.


----------



## buz

So I just received an AD797BR from audjade. I'm wondering now, is it better to put it into my M-Stage (current OPA2134) or in my NG98 DAC Stage (current LT1028)?


----------



## Mad Max

Try out both, see which you like it in better.


----------



## i_djoel2000

can someone recommend me and opamp that has good high and low extension?


----------



## leeperry

i_djoel2000 said:


> can someone recommend me and opamp that has good high and low extension?


 

 Where do you plan on using it? There's no "one size fits all"


----------



## Mad Max

Unless an HDAM fits in there.


----------



## leeperry

oh yah, sure: http://www.head-fi.org/forum/thread/413748/audiotrak-prodigy-cube-has-anyone-heard-of-this/15#post_6251920


----------



## svyr

Any tips for Stax driver op-amp setups? (need to single ones I think). The SRM-300 I bought off neob has sockets fitted: 
   
  Initially it had 2xLF 353N inside. 
   
  Now it's running 2xLME49720HA but it sounds somewhat fatiguing.
   
  neob said he was told 2xAD826 sounds nice in it.  (or rather may sound nice)
   
   
  I was going to try my 2xOPA627BPs, but then I managed to snap one of the chip legs and it's stuck (the leg piece that is) in the adapter I used in my Aune mk2... Any tips on getting it out (It's inside the gold plated metal hole of the 2x to dip 8 adapter)?


----------



## Yoga Flame

Quote: 





svyr said:


> I was going to try my 2xOPA627BPs, but then I managed to snap one of the chip legs and it's stuck (the leg piece that is) in the adapter I used in my Aune mk2... Any tips on getting it out (It's inside the gold plated metal hole of the 2x to dip 8 adapter)?


 

 Which pin? If you're lucky, it's pin 8, and you can just leave it off since it's not used by the OPA627.
   
  Otherwise, maybe you could try soldering some scrap wire onto the stuck pin and then yank it out. Or is it stuck too deep inside?


----------



## svyr

_
  |_.|
   

   
  The corner pin closest the dot indicating which side to insert the op-amp. (I have strange feeling it's pin 1)
  (p.s. wow, big pic of the wrong op-amp, but I hope you understood which pin I meant)
   
  p.s.s yep, it's rather deep. Guess I could still try the solder/yank method - worth a try before getting another 2xsingle to dual adapter.


----------



## Yoga Flame

Yeah, the corner dot is pin 1. That's too bad. Should be fixable with some careful soldering though, as long as there's still some of the leg left. I would use a heat sink to be on the safe side.


----------



## svyr

It snapped in half. (i.e. just the thin bit of the leg, not the tick one)
   
  Aside from the question about an op-amp for the stax, 
   
  I also need one for the Aune mk2 now, since I broke the 627BP . Any advise?


----------



## 12Bass

Pin 1 is for offset trim, so it probably is not used.  Chances are the the pins being used are pins 2,3,4,6, and 7.  

 Perhaps be a little more careful next time...


----------



## svyr

I should probably get the chip extraction tool... It's likely cheap and saves money. 
  Tweezer-like or 'sucking pen' lol?
   
  But yea... The opamps came with my used Aune mk2, so I didn't really realize I was handling ~$15...
   
  Some of the other pins are slightly bent as well. Best way to straighten them? (or just leave them alone so they don't snap?)
   
  Quote:


> Perhaps be a little more careful next time...


   
  So, for alternatives for Aune and SRM-300, any comments on:
   
  LT1364, LM6172, TLE2142, AD826, OPA627?


----------



## 12Bass

IC extraction tool?
   
  Straighten them very carefully... and don't over do it.  If the pins are close, they'll straighten themselves next time they are pushed into a socket.
   
  LM6172 is fast and might be unstable. From what I recall it was fairly "clear" sounding. The TLE series may be a bit better than the old TLO7X parts, but isn't as good as the better modern op amps, IMO. No experience with the others. Might try OPA827, AD797, AD825... depends on your taste.


----------



## svyr

>IC extraction tool?
   
  As per above (well, the edit). Tweezer-like tool and suction pen. Wondering which is the better one. I don't think I saw any small enough tweezer-like extraction tools (i.e. for 4 or 8 pin ICs). , plus on some of my gear access is blocked by caps and other soldered on things. 
   
   
  >LM6172 is fast and might be unstable
   
  Are LME49720 considered to be fast as well? (it's what I had in the Aune for a while and now migrated to the SRM-300). If so, should LM6172 be ok?
   
  p.s. as for AD825 and OPA827 - haven't seen any dip-8 ones (don't want to solder it, and the adapters make them almost 2x the original price?)
   
  p.s.s. re: taste - something like lme49720, but not as harsh for highs - i.e. present and detailed mids and bass, overall balanced or slightly mid centric, no harsh highs? (2am descriptions aren't fantastic, I know)


----------



## beerguy0

Quote: 





svyr said:


> I should probably get the chip extraction tool... It's likely cheap and saves money.
> Tweezer-like or 'sucking pen' lol?


 

 The tweezer-like tools are for thu-hole parts, while the suction pens are for handling SMT devices while placing them on the PWB to be soldered.


----------



## svyr

>for handling SMT devices while placing them on the PWB to be soldered.
   
  aaaah. okies...Thanks for clarifying! In that case I don't need it, but having ordered both for a nominal price of each $2.5 incl shipping I'm probably not sorry for buying them both


----------



## 12Bass

Quote: 





> Are LME49720 considered to be fast as well? (it's what I had in the Aune for a while and now migrated to the SRM-300). If so, should LM6172 be ok?
> p.s. as for AD825 and OPA827 - haven't seen any dip-8 ones (don't want to solder it, and the adapters make them almost 2x the original price?)
> 
> p.s.s. re: taste - something like lme49720, but not as harsh for highs - i.e. present and detailed mids and bass, overall balanced or slightly mid centric, no harsh highs? (2am descriptions aren't fantastic, I know)


 
   
  LME49720 is faster than some... but the slew rate of the LM6172 is considerably higher.  Some chips require extra supply bypassing or they will oscillate, usually at ultrasonic frequencies.  If you don't have a scope, you can do a finger test to see if they get hot.
   
  That description sounds like you might enjoy OPA827, which I find warm, yet detailed, and nicely present in the midrange.... not harsh or sterile, IMO.  Of course, that would require two on an SOIC => DIP adapter.  Lots of the better op amps come as SOIC singles.


----------



## svyr

>but the slew rate of the LM6172 is considerably higher. Some chips require extra supply bypassing or they will oscillate, usually at ultrasonic frequencies. If you don't have a scope, you can do a finger test to see if they get hot.
   
  I see, thanks. I think my list had a couple of >100V/us chips, so I take it this is a possibility for all of them. Is there anything I can do to determine whether it'll oscillate on my setup before buying and installing it and then doing a 'lick-test' 
	

	
	
		
		

		
			





?
   
   
  >Of course, that would require two on an SOIC => DIP adapter. Lots of the better op amps come as SOIC singles.
   
  Heh, my smallest soldering iron has a tip the size of the soic op-amps 
	

	
	
		
		

		
		
	


	




....Guess I can ask some of the sellers on ebay. A lot of them also sell adapters.


----------



## Mad Max

So I've been spending some time with a new round of opamps:
   
  ISL28127FB: Very low noise floor, a bit more than 4627-1. Extremely clean, smooth, and well nuanced with wide soundstage, yet stereo separation isn’t all that good, I’m not sure how to describe it. Very refined and neutral, though not as neutral as 4627-1B, it is pretty close. It is slightly laid-back with okay articulation and lacks a little timbral transparency, not sure. Slight hint of "yellowish-brown" in its tone.

 AD8597AR: Very clean and smooth, kind of artificially analogue-sounding, crazy articulation. The midrange is simply thrilling at first, but then I get bored quickly of the sound. It tries too hard to sound exciting and over-articulates every sound. Bass is too forward.

 OPA1611: Very warm and slightly energetic at first, but the color went away with burn-in, now it is more or less neutral. Very good overall with good detail and clarity and what not. Slightly lacked bass compared to the other opamps at first, but then got a bit bassier later. This one has a very wide soundstage like ADA4841-1.  Articulation and timbral transparency is very good.  I think it does still retain a touch of color, but I can't quite put my finger on it.

 THS4081: Very neutral, clean, clear, very  detailed, highly articulate without overdoing it like AD8597 and very accurate, kind of natural-sounding and smooth. Crystalline sound with weighty, wicked bass response and tightness. It brings out sounds towards the far left and right like 4627-1. Very beautiful sound overall. Heck, I don't hear a whole lot of difference between this one and 4627-1B. Dang, this one is just more detailed and a touch tighter. Great low bass. This is one of the best opamps I've ever heard.

 THS4051: Very neutral, clean, clear, very  detailed, highly articulate without overdoing it like AD8597 and very accurate, kind of natural-sounding and smooth. Crystalline sound with weighty, wicked bass response and tightness, but a bit less bassy than 4081. It brings out sounds towards the far left and right like 4627-1. It is like a slightly lesser 4081.

 LT1115: Very clean, articulate, neutral. It is very similar to THS4081... Well good grief! This one also sounds a lot like THS4081 and ADA4627-1B. It doesn't seem to be quite as extended at the extremes, though. A slight difference. Overall a touch closer to THS4081 than ADA4627-1B.  It didn't like my portable amp for some reason, but has wonderful timbral synergy with the Compass DAC.

 ADA4004-1: Very clean, pristine, neutral. A bit bassy, though not as much as 797 or LT1028, and very intimate. Bass and lower mids are slightly smoother than the other opamps.  Wonderful sound.

 LT1677I: Very clean, pristine, neutral as well with good detail. Slightly lacks bass compared to the other opamps I've tried.  Somewhat inarticulate. It sounds slightly greenish-white.  It is slightly bright, probably from the slight lack of bass, though I think there may be a slight hump in the treble, around the beginning of the upper treble I think or a little lower, not sure.  I'm really liking female vocals on this opamp over the others in this round.

 OPA827:  Almost neutral, very clean, clear, and fluid. Decent detail, it seems to have a very slight smiley curve to its sound.  Reminds me somewhat of 4627-1B, but a pinch aggressive.  Wonderful sound, slightly rich and a bit tuneful.  Not quite as transparent as some of the others.  Excellent articulation.  This one is kind of nice with my SR325is, but the lack of resolution is a bit of a bottleneck for the Grado grunge.
  
  I may add to this later.


----------



## leeperry

I agree on AD8597AR, it's trying too hard to impress...but fails blatantly.
   
  OPA1611, no likee...don't remember why. typical Boring-Boring IIRC.
   
  LT1115 isn't unity gain stable, it's a lower grade of LT1028 I think...and it was audible too.
   
  LT1677I: yes, too bright and harsh...not very colorful.
   
  OPA827: usual BB sound...not my thang.
   
  so what's your all-time favorite you crazy roller?


----------



## Mad Max

I didn't find 1611 to be bad in any particular way.
  Or 827, nor did it sound like a "typical" burr brown.
  I didn't find 1677 harsh either.
   
  What did you test them in?
   
  All-time favorites?  It would have to be a toss up between 4081A and 4627-1B.
  I have loved AD744AH, OPA1611A, ADA4004-1, AD8091, and Sun, and OPA1641 is another good one.  Hard to decide whether to call 1641 a favorite, it is very good overall but the loose bass... =(


----------



## krisno

forget it.....


----------



## ROBSCIX

Quote: 





mad max said:


> I didn't find 1611 to be bad in any particular way.
> Or 827, nor did it sound like a "typical" burr brown.
> I didn't find 1677 harsh either.
> 
> ...


 
   
  The OPA1611,1612, were well liked by many around here.  I noticed you tried some of the THS series, have you had a chance to test out the THS4032 or the singles THS4031.  It seems many people recommend these for I/V section for DAC's.  They can be rather unstable if used improperly.
  Have you done any further testing with the mentioned units?


----------



## leeperry

mad max said:


> I have loved AD744AH, OPA1611A, ADA4004-1, AD8091, and Sun, and OPA1641 is another good one.  Hard to decide whether to call 1641 a favorite, it is very good overall but the loose bass... =(


 

 I hated Sun-V2, it's missing so much stuff that it was making me feel half-deaf..majkel also mentioned this lack of "substance".
   
  I've got some OPA1641, kinda lazy to solder them though.


----------



## Mad Max

Andrea told me I wouldn't be missing much by skipping 4031/3032.  Further testing? Like what?  I don't have anything else to test them in except Minibox-E+ and my Compass DAC.  I've been pondering about getting another opamp test bed, perhaps an NG98 or P3+, they seem to offer more possibilities for combining opamps and what not.
   
  Sun is really funky with its roller-coaster FR, it can even play tricks on you too. 
	

	
	
		
		

		
		
	


	



  Once you get used to it, it is really fun, but definitely an acquired taste.
  I don't find that it really lacks anything, it is just quite different.
   
   
  Is it the aim of opamps to sound neutral with cleaner power and a circuit they are suited for/compatible with?
   
   
  Edit: w00t! Successfully installed ADA4841-2 in place of OPA2338 in my FiiO E5.  Much cleaner sound.  Now to test the battery life...


----------



## leeperry

I loved it when Audio-GD told me that many recording studios were buying Sun-V2 to install in their mixing boards..hahaha their main salesman should consider stand-up comedy 
   
  Even an opamp w/ +120dB PSRR still benefits from a clean PSU, it's about dirty ground I think.
   
  If I were you, I'd avoid anything from HA-Info..


----------



## cent

I had opa2111kp for treble and opa2107ap for bass soldered in my amp, I found that it is lacking of low mid(whispering is barely audible in movie).

 What opamp shall I change for my xonar essence stx to gain the low mid for easy listening with wider soundstage, clearer and warmer sound?
 I have opa2132pa, opa2111kp, opa2107ap, opa2277pa, opa228pa, lt1028, lt1363 and lt1364 here.


----------



## majkel

Quote: 





leeperry said:


> I loved it when Audio-GD told me that many recording studios where buying Sun-V2 to install in their mixing boards..hahaha their main salesman should consider stand-up comedy


 


 I appreciate their sense of humor.


----------



## leeperry

I also love when MOT's explain that the 5532 is teh best opamp evar to drive headphones: http://www.head-fi.org/forum/thread/223006/benchmark-dac1-now-available-with-usb/2940#post_6809841
   
  together w/ those 4562(presumably used as DAC filters) = killer combo!
   
  in that shootout, the DAC1 was said to be so-so: http://ravenda.wordpress.com/2009/08/14/audiogddac19/


----------



## Mad Max

Quote: 





cent said:


> I had opa2111kp for treble and opa2107ap for bass soldered in my amp, I found that it is lacking of low mid(whispering is barely audible in movie).
> 
> What opamp shall I change for my xonar essence stx to gain the low mid for easy listening with wider soundstage, clearer and warmer sound?
> I have opa2132pa, opa2111kp, opa2107ap, opa2277pa, opa228pa, lt1028, lt1363 and lt1364 here.


 

 Why don't you try something more balanced-sounding?  Can you solder?
   
   
  ADA4841-1 has the widest soundstage I've heard, as well as OPA1611.  4841 is kind of natural-sounding as far as soundstage, a pinch warm, too.  I can't remember the others right now.  I keep forgetting to check opamps' soundstages with RE-252, its soundstage is the most sensitive in my arsenal.
  You could also try AD8065/8066 or AD744/746.  If you decide on AD744, I recommend you shoot for the ceramic dip version (744KN) or the metal can version (744AH) if possible.


----------



## Mad Max

Oh man, I'm liking the FiiO E5 again.  With 4841-2 the soundstage is more natural and overall the sound is more detailed, cleaner, clearer, and slightly tighter. It still can't lay finger on my Minibox-E+, but for the twenty bucks it sells for, this thing is real nice with an opamp change.


----------



## ecclesand

Quote: 





robscix said:


> The OPA1611,1612, were well liked by many around here.  I noticed you tried some of the THS series, have you had a chance to test out the THS4032 or the singles THS4031.  It seems many people recommend these for I/V section for DAC's.  They can be rather unstable if used improperly.
> Have you done any further testing with the mentioned units?


 

 I just ordered a couple of the THS4031 and some .01uF PPS caps to solder across the rails for stability.  I plan to use them in the I/V stage of an Assemblage DAC I just picked up.  I too heard they were great for this very purpose.


----------



## cent

Quote: 





mad max said:


> Why don't you try something more balanced-sounding?  Can you solder?
> 
> 
> ADA4841-1 has the widest soundstage I've heard, as well as OPA1611.  4841 is kind of natural-sounding as far as soundstage, a pinch warm, too.  I can't remember the others right now.  I keep forgetting to check opamps' soundstages with RE-252, its soundstage is the most sensitive in my arsenal.
> You could also try AD8065/8066 or AD744/746.  If you decide on AD744, I recommend you shoot for the ceramic dip version (744KN) or the metal can version (744AH) if possible.


 
   
  Yes, I can solder but the onboard tracing for the DIP-8 is worn so not dare to desolder it again.
  Actually the opa2111kp is the replacement for my stock st4558, I'm afraid that circuit cannot support any higher speed opamp.
  Now searching for the opamp for I/V and buffer on soundcard to pair with my amp to get the sound I desired for.


----------



## cent

Yes, I can solder but the onboard tracing for DIP-8 is worn so I not dare to desolder it anymore.
   
  Actually the opa2111kp for my amp's treble is a replacement for the stock st4558, I'm afraid it won't be stable changing to higher speed opamp.
   
  So the best I can do now is try to change the I/V and buffer opamp in my sound card xonar essences STX to pair with my amp and get the sound I desired for.


----------



## ROBSCIX

Quote: 





ecclesand said:


> I just ordered a couple of the THS4031 and some .01uF PPS caps to solder across the rails for stability.  I plan to use them in the I/V stage of an Assemblage DAC I just picked up.  I too heard they were great for this very purpose.


 

 Let me know what you think when you get them soldered up and tested.  I always keep a few dual THS4031 and THS4032 modules around for testing.


----------



## ecclesand

Hmmmm....gave them about 48 hours and they sound OK in the I/V stage of the Assemblage DAC.  I pulled them and dropped in a pair of OPA827.  To my ears, the OPA827 sounds much better than the THS4031.  At least the THS and the caps were cheap.


----------



## genclaymore

You guys know any netual op-amp to be used with my AKG 702s which are coming tommow? I knoww about the earth,but something as a pdip til I get around to getting a OPA-earth.


----------



## gwillys

need some advice. i've found that my aune/hifidiy mini usb dac sounds best with no opamps. i only use rca out, so i'm pretty sure only the opa2604 is in play here.
   
  without opa's, the volume control on my ext. amp makes static only when it's turned. and when switched off, the dac's power led stays lit, but fainter. so i measured across ground, and there's 8v. probably not a good thing, but the equipment shows no stress.
   
  besides slightly reduced volume output, which is of no consequence, it sounds great.
   
  i'm wondering if anyone can help a novice rectify this. i was thinking maybe some type of jumper/resistor/cap across opa socket, but i don't know enough to attempt that. i did put a cap between pins 4 & 8, but no change.


----------



## Yoga Flame

I'm guessing you removed the opamp in the DAC position, and left the OPA2604 in the amp position. I tried removing the DAC opamp too, but I wouldn't say that it sounds best that way. FWIR the opamp in that position is used as a low pass filter. So there might be some high frequency noise without the filter being used (at least that's how I understand it).
   
  I think OPA2604 might be the bottleneck for you. In my experience that did not work very well in the Aune compared with the other opamps that I tried.
   
  I don't really have an answer to your question. But I think you are looking for a "dummy op-amp". I recall reading something about that from Dr. Xin. It was pretty much just a couple of jumpers in a DIP-8 socket, if I remember correctly.
   
   
  (Just so everyone is clear, the Aune will still work without the DAC opamp in place, only with lower volume and maybe a little more noise. *edit:* The _headphone out_ will not work at all without the output opamp in place. But the _line out_ will work.)


----------



## gwillys

thanks, but for line out, which is the only way i use it, it works without both opamps. yes, maybe a dummy opamp would work, i'll see what i can find on dr xin.


----------



## Yoga Flame

Ah, okay. Thanks for the correction. I had not tried the line out that way before. Edited my post to fix the inaccuracy.


----------



## leeperry

You might like this thread: http://www.head-fi.org/forum/thread/270984/best-op-amp-for-x-fi-prelude-meridian-or-socketed-soundcard-if-using-an-amp-is-none#post_3450796
   
  On the Prodigy HD2 there's 3 dual opamps: 2 used as AK4396 LPF and one bringing them to line-out level. I could remove the latter, but then the sound was thin/bass-shy and dull.
   
  From now on, I want to have as little opamps as possible in the signal path, two single opamps used as DAC LPF > done. PCM1793 does just that and sounds awesome.


----------



## gwillys

audiogd dac-19 has no opamp in signal path. probably the way i'll go.
   
  the aune/hifidiy mini dac sounds pretty darn good with the opa's yanked out. with a better psu & mods like super regulators, burson clock, recap with silmic II it would be really nice. though expensive and not very practical. i'm getting tired of all this modding. there is so much marketing hype with all this stuff, it gets expensive trying to sort it all out. one thing i'm certain of at this point, for a dac, no opamp is the way to go. cost me alot of money and time to discover that.


----------



## leeperry

yeah, that's where I don't agree...discrete designs from A-GD/Burson measure very poorly, they WILL color the sound to death. Nothing beats a good IC opamp IME, these are pieces of highly engineered technology...just don't use many of them in a row, so you don't color the sound too much. And take your time finding your favorite opamp, it's where the fun resides.
   
  Discrete isn't "better": http://www.head-fi.org/forums/f6/audio-gd-discrete-op-amps-reviewed-OPA-earth-OPA-moon-OPA-sun-v-2-a-397691/
   
  Properly built discrete can be good, though. Look at the Neko DA100 AP measurements on their site: http://assets.head-fi.org/0/08/08ffecd6_DSC01272.JPG


----------



## gwillys

being old school, i think i'll be much happier not having to mess with opamps. besides, opampless is the best i've heard from digital audio so far.
   
  a jumper across  pins 3 and 5 of the socket seems to work pretty well.
   
  i have a bunch now, maybe i'll have a yard sale


----------



## genclaymore

I in up putting my OPA2111AM back in because 2xOPA228s made my Highs not sound right and got annoying to my ears after awhile and didnt sound fuller to me. I was hoping to find something that was netual that didnt have more bass While still having a big sound stage while still sounding fuller.


----------



## Mad Max

K702, huh?
   
  You'll probably want opamps with higher output current, I think.
  You'll probably like EL2125/2126.  Not sure if EL2228/2227 might work for you.  ISL55001/55002 is also excellent.


----------



## leeperry

*"*_EL2125 is stable for gains of 10 and greater_", which parts would you recommend from intersil? you know my tastes


----------



## Mad Max

That's why I suggested several for him to choose.  He didn't specify where they would be used.
   
  You will probably like ISL28127 and 55001. EL2045 and 2126 are real nice, too, but might not be to your liking.  I've already forgotten how 2126 and 2125 compare, I think I liked 2125 better.


----------



## ecclesand

Quote: 





mad max said:


> That's why I suggested several for him to choose.  He didn't specify where they would be used.
> 
> You will probably like ISL28127 and 55001. EL2045 and 2126 are real nice, too, but might not be to your liking.  I've already forgotten how 2126 and 2125 compare, I think I liked 2125 better.


 

 Hmmm...this is the first I have heard of these Intersil opamps.  What would you recommend for high impedance headphones like the 600ohm DT990 in the I/V and Buffer stage of a DAC?  I think the EL2045 might be the ticket for the buffer.  Can you recommend one for the I/V stage?


----------



## genclaymore

They would be used in my Bravura headphone amp op-amp socket,


----------



## Mad Max

So scratch EL2125/2126.
   
   

  
  Quote: 





ecclesand said:


> Hmmm...this is the first I have heard of these Intersil opamps.  What would you recommend for high impedance headphones like the 600ohm DT990 in the I/V and Buffer stage of a DAC?  I think the EL2045 might be the ticket for the buffer.  Can you recommend one for the I/V stage?


 

 I don't have a DAC that I can test them in I/V, only buffer.
  Intersil has a bunch of real nice looking, and sounding, opamps.


----------



## Avro_Arrow

Hi All
   
  I'm looking for op-amp recommendations.
  I'm building a DAC based on PCM1794 and would like
  opinions on which amp for I/V stage and Filter stage.
  Schematic is just the standard one from the data sheet.
   
  And no, I don't want to do a tube or discrete stages,
  maybe in the next one.
   
  I like the sound of LT1364 which I use in my PCM1793 DAC.
   
  Thanks


----------



## leeperry

they recommend LT1028/1128 in the PCM1794 datasheet I think


----------



## Avro_Arrow

I know I could just use the amps recommended in the data sheet...but...
  
  Quote: 





leeperry said:


> they recommend LT1028/1128 in the PCM1794 datasheet I think


----------



## leeperry

well, LT1028ACN8 sounds very very good..together w/ LT1363, they're many ppl's favorite chips. I love both, but 1028 is too cranky to roll blindly.
   
  If TI didn't recommend one of their crummy OPA____, there's a good reason.


----------



## Mad Max

Dunno if THS4081 would work in I/V.  Extremely neutral and transparent opamp, doesn't sound green like other video opamps either.


----------



## jcx

I've pointed out over on diyaudio that the new ADA4898 has unusual technical properties that could make a very good I/V op amp
   
  a detail that doesn't appear on the data sheet is that it uses Gilbert's multi-tanh input linearization with a more recent patented twist
   
  the ADA4898 multi-tanh linearizes the input diff pair to 1 ppm gm change at ~4 mV diff Vin - and I/V needs large linear input due to the I switching edge frequency content


----------



## TigzStudio

So I read through this entire thread, painfully, from start to finish.  What I gathered?  That basically everyone goes back and forth from liking one to not liking it, then a new one pops up... etc etc rinse and repeat.  There really doesn't seem to be a definitive opamp that people like and will stick with no matter what.  No end all opamp for anyone?
   
  The ones that seem to be leaning in everyones favor would be the AD797 and the LT1363/4.  
   
  In all of the opamp rolling what is the most neutral opamp you have encountered?  That is my ultimate goal.  If you can please list the *one *that beats all in this regard even if slightly.  I am not looking for colorations of any kind.  
   
  Thanks!
   
  btw: I would be swapping out 4x5532's in this amp


----------



## majkel

Quote: 





> In all of the opamp rolling what is the most neutral opamp you have encountered?  That is my ultimate goal.  If you can please list the *one *that beats all in this regard even if slightly.  I am not looking for colorations of any kind.
> 
> Thanks!
> 
> btw: I would be swapping out 4x5532's in this amp


 


 When I really have to use an op amp, I refer to OPA228 family. Otherwise, I skip op amps where possible.


----------



## amb

Quote: 





tigzstudio said:


> So I read through this entire thread, painfully, from start to finish.  What I gathered?  That basically everyone goes back and forth from liking one to not liking it, then a new one pops up... etc etc rinse and repeat.  There really doesn't seem to be a definitive opamp that people like and will stick with no matter what.  No end all opamp for anyone?


 
  What do you expect from such opamp fetish? 
	

	
	
		
		

		
			




   
  Quote: 





> If you can please list the *one *that beats all in this regard even if slightly.  I am not looking for colorations of any kind.


 
   
  Good luck...  there are at least a couple things which makes that impossible:
   
  1. Most people here talk subjectively about the "sound" of the opamp, but what's "neutral" or "uncolored" is a perceived entity and subject to interpretation.  (e.g., What one person considers "neutral" might sound "bright" to some and "laid back" to others).  What those words mean, even, are also fuzzy.
 2. The opamp isn't the only factor at play here.  What circuit it's installed in also has an effect on the sound.  Sometimes more so than the opamp itself.


----------



## TigzStudio

Hmm good points, so I guess it really comes down to.... what amplifier design (that does not use opamps) is the least altering of the original signal.  
  Quote: 





amb said:


> What do you expect from such opamp fetish?
> 
> 
> 
> ...


----------



## TigzStudio

Well I think for now I will just swap out the 4x5532's with this:
   
  http://www.national.com/pf/LM/LME49723.html#Overview
   
  or the LM4562


----------



## majkel

I suggest using LME49860NA. Surely better than the LM4562.


----------



## Avro_Arrow

So ADA4894 in the I/V role and LT1363 for the Filter role.
   
  I want to use the soic version soldered directly to the board
  so rolling would not be a very good option, thats why I would
  like to start out with the best (oh, there's that word again...)
  amps for those uses.
   
  Thanks for your input.


----------



## jcx

my fingers slipped in my I/V op amp recommendation post - that would be ada4898, I fixed my post
   
http://www.analog.com/static/imported-files/data_sheets/ADA4898-1_4898-2.pdf
   
  from info provided by Scott Wurcer it appears to use US 6963244 Common mode linearized input stage and amplifier topology


----------



## Avro_Arrow

No wonder I couldn't seem to find any information about it...
   
  Quote: 





jcx said:


> my fingers slipped in my I/V op amp recommendation post - that would be ada4898, I fixed my post
> 
> http://www.analog.com/static/imported-files/data_sheets/ADA4898-1_4898-2.pdf


----------



## Avro_Arrow

The LT1363 data sheet mentions that it is suitable for the I/V role...could I not
  use it for both the I/V role and Filter role and maintain it's high slew rate?
   
  Any opinions on this?


----------



## jcx

only technical opinions...
   
  lt1363 9 nV/rt(Hz) input noise is high for I/V role
   
  slew rate requirement in audio is not 1000V/uS, - like output Vswing or current limit once you have sufficient margin over what the signal, load requires there is no obvious good from having orders of magnitude more
   
  I highly advocate using a feedback C in a op amp I/V to give a low pass filter below 100 KHz - limiting slew requirement to  ~1 V/uS per V of output swing - with desktop consumer 2 Vrms output this means the "only" 55 V/uS ada4898 is already 10x faster in slew rate than the highest possible 100KHz filtered DAC I/V output


----------



## Avro_Arrow

Yes, I agree. I keep the ADA4898 for I/V.

 The data sheet quotes a 2200pF cap in parallel with 750 ohms for the feedback in the I/V section
  Is there any reason I should alter these values for use with ADA4898?
   
  I did like the ADA4898 noise figues...
   
   
  Quote: 





jcx said:


> only technical opinions...
> 
> lt1363 9 nV/rt(Hz) input noise is high for I/V role
> 
> ...


----------



## Mad Max

Quote: 





tigzstudio said:


> So I read through this entire thread, painfully, from start to finish.  What I gathered?  That basically everyone goes back and forth from liking one to not liking it, then a new one pops up... etc etc rinse and repeat.  There really doesn't seem to be a definitive opamp that people like and will stick with no matter what.  No end all opamp for anyone?
> 
> The ones that seem to be leaning in everyones favor would be the AD797 and the LT1363/4.
> 
> ...


 

 There are a few I've tried that are the most neutral, and 1363 is one of them, but it requires really clean power or it will sound colored.  AD797 is [pleasantly] colored, but pratless and has crappy treble.
  ADA4627-1B is the very best I've heard along with THS4081, the latter of which needs very clean power as well.


----------



## razzz42

I'm on the sidelines here since I'm handicapped technology wise. but hasn't this 'no amp' been discussed before starting somewhere around here....http://www.head-fi.org/forum/thread/287617/prelude-with-opa627-opamp#post_3693471
   
  Not arguing the point as it is the finally the first thing that makes any sense as to listen to sounds as recorded on a pass through basis maybe some filtering needed but that is about it.
   
  Then this leads back to the sound processing chip itself, in my case Envy Vinyl (which everyone seems to ignore which must be a good thing in this case) on a Prodigy HD2 Advanced DE. Just need a decent pass thru DIP8 or equivalent. (JP4 'on' just send the raw processing through, like for a home receiver to work with. )
   
  Glad I caught on before I spent to much money trying to change the original recordings.


----------



## jageur272

I'm thinking about using a LME49710 as the voltage gain stage of an amp I'm building.  Is there any advantage to using the TO-99 package as opposed to the SOIC or DIP packages offered?


----------



## Mad Max

TO-99 versions of opamps tend to sound a little better than their plastic and ceramic DIP versions.


----------



## Mad Max

Damn, HA3-2525-5 is a stunning opamp, but in my Minibox-E+ it is very noisy and a lot less in the Compass, but in the Matrix M-Stage, it just shines like  
	

	
	
		
		

		
			





  
	

	
	
		
		

		
		
	


	




  
	

	
	
		
		

		
		
	


	



  I'm loving these Intersil opamps more and more.


----------



## leeperry

mad max said:


> I'm loving these Intersil opamps more and more.


 

 Just when I thought I had finally controlled my Andrea-itis syndrom 
	

	
	
		
		

		
		
	


	



   
  ok, I'll bite! do they have any very fast opamp à la LT1363?


----------



## Mad Max

I think you should probably ignore my rants in this thread.  
	

	
	
		
		

		
		
	


	



   
  LT1363 sounds real good in the this amp, too.  Even Earth sounds decent.  It sounds like s*** in the Compass DAC, but in this amp it is good.  I think 2525's output current is what is giving it the edge against the rest.  Will take current measurements later, too busy rediscovering my music right now.  Surprised at how quiet 2525 is in this amp.


----------



## TuR3

Hi! I have an headphone amplifier with 2xAD8610. Which opamp with FET input and better characteristics and of course that will sound better, could i install to substitute them? Perhaps ADA4627-1?


----------



## majkel

OPA827, AD825, AD744 if SOIC version exists.


----------



## TuR3

Quote: 





majkel said:


> OPA827, AD825, AD744 if SOIC version exists.


 

 Thanks, i will search for them. Is there anything in PDIP package? My AD8610's are on browndog adaptors.


----------



## majkel

AD744


----------



## Avro_Arrow

LT1363
   
  Quote: 





tur3 said:


> Thanks, i will search for them. Is there anything in PDIP package? My AD8610's are on browndog adaptors.


----------



## leeperry

avro_arrow said:


> LT1363


 

 X2


----------



## TuR3

As i have understood reading the datasheet it has BJT input.
  Quote: 





avro_arrow said:


> LT1363


----------



## majkel

Quote: 





tur3 said:


> As i have understood reading the datasheet it has BJT input.


 

 Exactly. This is why I refrained myself from recommending anything but JFET input op-amps known to me as good sounding.


----------



## Soymilk

im debating between using a lm4562 or ad823 for my cmoy (i have both on hand). from my digging around i only see bad/unfavorable things about the ad823; should i just go with the lm4562?


----------



## dlaloum

Hi Folks
   
  I have an M-Stage on the way to me along with a Class A mod socket and a bunch of opamps to try out
   
  Could people who have played with the M-Stage please provide some feedback as to which opamps work well with the M-Stage (Lehmann Black Cube Linear) design, and which respond well to Class A (resistor) Biasing and how much biasing?
   
  The selection of opamps I will have early next week are:
   
   
 OPA627

 OPA637

 AD797

 AD744

 LT1028

 LME49860

 OPA2107

 OPA2111

 OPA228

 OPA49720

  

 I know some of these can be unstable in some circuit designs (AD797) but don't know enough to know what design or whether those comments apply to the M-Stage

  

 thanks


----------



## Mad Max

Welcome to the club.  
	

	
	
		
		

		
		
	


	



  
 OPA637  will work if you raise the gain
 LT1028  will oscillate
  
 The rest will work, most likely.
  
 Of that list, I have AD797, 744, LME49710/49720, and LT1028.  797 sucks the soul out of the music, even in the M-Stage and 49710's artificiality bothers me, but you may like them.  744 responds well to both class A and output bypass, I just haven't tried it in class A in the M-Stage yet.
  
 I recommend TL051 and especially HA3-2525-5 if you can get your hands on a pair.
  
 I have yet to bother with Class A, so I can't tell you how they respond, but I've seen posts here of people talking about how some of these respond to class A biasing.  Do a search.


----------



## qusp

only OPA228, OPA627, OPA637 and AD744 of those respond to class A bypassing IMO (try out THS4031 as well). some of the others actually are harmed by it, as they mostly operate in class A anyway and I really dont see how there can be such a thing as a class A biasing socket, surely the amount of resistance/bias needed should be modified for each chip you use....
   
  AD797 is tricky, you cannot just drop it into a circuit and expect it to do well, because of its very wide bandwidth and ultrafast nature, it needs bandwidth limiting, compensation and very good supply decoupling to work well in the audio band and to judge it without doing these things really isnt all that valid IMO. if in a circuit well suited to it, the AD797 is one of the best sounding opamps out there IMO, its one that I keep on coming back to to revisit. 
   
  you should definitely add OPA1641 and OPA827 to your list. these babies are pretty much perfect IMO and I am also of the jfet input opamp loving club. along with some of the CMOS opamps, but watch the bandwidth
   
  and if you are up for a bit of balanced opamp love, the newish THS4150 is sweet


----------



## dlaloum

As you say - I have seen substantial reports about the AD797 and it not being a drop in replacement.... Hence my question as to whether it will work in the Matrix M-Stage circuit.
   
  The Class A mod has been documented in a number of places around the web, and involves soldering 2 resistors between 2 sets of 2 pins...
   
  Like this:

  By doing it on a socket -  you reduce the risk of damage to board or opamp - and it is easily swapped in and out
  You can then also have seperate sockets for different biasing currents - so you can try things out easily.
   
  Finally for those who haven't touched a soldering iron in 15 years (like me), some of the vendors are providing the mod sockets at minimal cost (like coolfungadget.com )
   
  I have a spreadsheet in which I have been recording peoples comments about different opamps for reference - this will help me to choose likely ones to try first, and possibly also which ones will work best with the Class A mod and which biasing level may work best.
   
  Recomendations for OPA627 seem to be minimum additional biasing of 2mA and no more than 7mA - primarily due to heat (duh... class A right!)
   
  But if the opamps are singles rather than duals and mounted on a side by side adapter - a heatsink may allow to go 7mA safely.....although I don't know whether there is anything to be gained thereby.
   
  I've had reports that the HA3-2525-5 is particularly good in the M-Stage
  Also reports that the LME4562 (and relatives) get some benefit from the class A mod, but minor
  I've noted the OPA1641/827 on my list..... lets see how I go with my current collection though.
   
  My objective is to achieve a "Wow that's a real improvement" effect over my current options. (Onkyo receiver onboard NE5532+buffer headamp, Firestone Cute Curve+OBH2 PSU, ART Headtap connected to Onkyo speaker outs)


----------



## jageur272

Class A biasing with a resistor is silly IMO.  The current draw with a resistor across the output of the opamp will only remain constant if the voltage output is constant.  Because music consists of rapidly changing voltages, than you will have constantly CHANGING current draw.  Not only that, but you're also wrecking the output impedance of the op-amp.  It works (sorta), but there are better ways (though none as simple).  Tangent's website has information about biasing opamps into Class A.
   
  EDIT:
  Here it is: http://tangentsoft.net/audio/opamp-bias.html


----------



## dlaloum

Yep read that a few days back....
   
  obviously in a perfect world I would study electrical engineering and design my own perfect amp..... but in my imperfect world, with pockets of limited depth, and a lack of soldering skills, the trick is to find a good base design, and then optimise it as best I can...
   
  Concensus is that with some opamps (OPA627 being a prominent example!) there are tangible improvements to be gained from the crude resistor method (notwithstanding the flaws)
   
  So my choice is to select a good basic design (Matrix M-Stage / Lehmann BCL Clone) and use the optimisations different people have tried to achieve something closer to my own interpretation of perfection.
   
  I'm hotrodding a sedan, not creating a F1 racing car....


----------



## Avro_Arrow

You could do that same trick with the IC socket but use a CDR instead of a resistor.
  
  Quote: 





dlaloum said:


> Yep read that a few days back....
> 
> obviously in a perfect world I would study electrical engineering and design my own perfect amp..... but in my imperfect world, with pockets of limited depth, and a lack of soldering skills, the trick is to find a good base design, and then optimise it as best I can...
> 
> ...


----------



## dlaloum

Excuse my ignorance .... what is CDR?


----------



## jageur272

Quote: 





dlaloum said:


> Excuse my ignorance .... what is CDR?


 

 CRD, right Avro Arrow?  Current Regulating Diode.


----------



## dlaloum

Thanks - tracked it down just before you posted....
   
  Looks easy to use too.... looking into it now


----------



## Avro_Arrow

Yes, clumsy fingers...
  Quote: 





jageur272 said:


> CRD, right Avro Arrow?  Current Regulating Diode.


----------



## dlaloum

Hah I should have read further in the Tangensoft article - I stopped at the initial JFET stage..... looked at it - thought too hard, too much soldering involved and got no further!
   
  But as you say CRD's (see how easily that rolls off the keys now I know what it means!) would be no more work than resistors....
   
  There is a comment in there about input capacitance - anyone know what the impact of the input capacitance on sound would be?
   
  So searching through google for CRD info...
   
  What CRD's would allow for Biasing currents of between 2mA and 7mA .... @ 15V - target is likely around 4mA but I would like to be able to compare various options...
   
  I am seeing various devices - and there is talk of "max limiting voltages" fwd current, etc... (gobbledygook to me)
   
  It looks like the Vishay Siliconix J508(2.4mA), J510(3.6mA), J511(4.7mA) might fit the bill - but they are also marked as max limiting voltage of around 4V - what does this mean
   
  Had anyone tried this approach?


----------



## genclaymore

I wondred how LT1364s would sound with my AKG 702, So I pop them in my I/Vs, Sound good execpt The Piece Highs ruin it. But other then that I liked them. Just wish they didnt make my highs sound like that thru my AKG702s. So I in up poping 2x OPA2137P's back in.
   
  I really wanna get ahold of 2 Sets of AD797s in the future and try them with my AKG 702s.


----------



## Mad Max

You probably won't find the highs so piercing with 797 indeed.


----------



## @@anderson@@

First post on the Opamp here. I need some help here i have a choice of 
   
  (2 single Opamps) opa134, Ne5534
   
  (Dual Opamp) 
   
  ad823, ad827aq, opa2604, ne5532 
   
   
   
  thanks a lot


----------



## dlaloum

Not that I am an expert but...
   
  All things being equal 2x singles are reputed to give better sound.... they also have potentially better heat dissipation if you are running in class A - allowing them to be biased further into class A potentially.
   
  On the other hand if you are swapping into a pre-existing circuit with a spot for a dual, then consider that putting a dual in avoids additional adapters/sockets and extended circuit traces with possible resulting reductions in audio fidelity.
   
  Personally I would opt for the twin singles - I think that the gain might be greater than the loss..... but results do vary and the "suck it and see" method is always best


----------



## leeperry

@@anderson@@ said:


> I need some help here i have a choice of
> (2 single Opamps) opa134, Ne5534
> 
> (Dual Opamp)
> ...


 

 all rather poor choices....some food for thoughts: http://www.head-fi.org/forums/f6/audio-gd-discrete-op-amps-reviewed-OPA-earth-OPA-moon-OPA-sun-v-2-a-397691/
   
  and you didn't mention what unit those were aimed at being rolled in.


----------



## dlaloum

Current Regulating Diodes - Help....
   
  I have identified a number of sources for CRD's - (to make Class A opamp mod sockets...)
   
  In addition to the current regulation specs in mA - there are various other specs mentioned - in particular voltages etc...
   
  Could someone please tell me what I need to look for in terms of specs on a CRD for it to work in a Class A opamp upgrade mod with a +/-15V PSU
   
  They are relatively pricey, and I would hate to pick up a bunch of bits that fry the first time I try to use them...
   
  Also anything else I should look out for?
   
  I am intending to use the method as described in http://tangentsoft.net/audio/opamp-bias.html option 3.
   
  On a Dual opamp socket - which pins should I be soldering to and in which polarity....?
  Thanks


----------



## K3cT

I haven't posted in a long time here but the ADA4627-1 still remains there as my #1 op-amp in signal.


----------



## Nightslayer

I'm quite a noob when it comes to circuitry, so excuse me if I sound extremely unintelligent. I have a CMoy that runs on a single 9Volt battery, and I recently changed my OpAmp from OPA2134 to the OPA2227, looking for a less laid-back tube-like sound. What I'm trying to get out of the amp is mainly transparency, speed/clarity/detail, and an increased bass quantity/body and full bodied mids (for my 43Ohm DBA-02s). I've done a bit of research and come up with a few (okay a lot of) choices, and I'd appreciate it if any of you could comment on any of them with regards to the soundsig I'm looking for before I make the trip down to the store (which isn't going to be very convenient ><) to make purchases.
  TLE2082CPE4
  LT1355
  LT1677
  ISL28127
  AD797ANZ
  AD825
  AD823
  AD845KN


----------



## Mad Max

Andrea recommends TLE2062 for cmoys without buffering, TLE2082 for buffered applications.
   
  LT1677 slightly lacks bass compared to other opamps I've tried, but it is still quality bass.  Lacks articulation, though - it slurs sounds together, but I hear this in most of the LT chips I have.  ISL28127 will be excellent if it works in your amp, but it is not very detailed unless you end up not minding then you will love it.
   
  I personally don't like 797, but qusp says it needs accommodations, maybe he can help you.


----------



## SpudHarris

Haven't posted here for a while as I'm more into tubes than chips at present. The AD797BRZ is really the benchmark in my opinion it is the OpAmp equal to Tung-Sol Black Glass Round Plate 6SN7 only easier to get and hundreds of times cheaper. Not as romantic though 
	

	
	
		
		

		
		
	


	



   
  I haven't swapped the 797's out of my Fi-quest for months and months, they are just so perfect to my ears........


----------



## mark2410

btw anyone wouldnt know of a reasonable and cheapish desktop amp that could be used primarily for testing opamps, you know nice and easy to get to and swap out.


----------



## murrays

Quote: 





mark2410 said:


> btw anyone wouldnt know of a reasonable and cheapish desktop amp that could be used primarily for testing opamps, you know nice and easy to get to and swap out.


 

 Trying them in another circuit probably won't tell you what you want to know (as far as sound qulaity and stability go).  Each circuit is different, so you're best to do all your serious testing in your amplifier of choice.  On the other hand, maybe you just wanted to do a "go / no-go" test ? ...


----------



## Nightslayer

Uh. What's the average price for an SOIC-DIP adapter? The AD979BRZ looks interesting but it's SOIC, and the place I'm intending to buy my parts from sells the Browndog adaptors at $167 :O


----------



## SpudHarris

Go direct to Cimarron they ship world wide.


----------



## leeperry

as much as I find AD797B impressive, I find it boring and its SS too colored...it's got that amazing SS depth, but it's too predictable and clearly doesn't exist in the record.
   
  LT1028ACN8 is too cranky, so LT1363CN8 is as good as it gets for me. The tighest bass I've ever heard and more details than any phone could possibly output. It's got a low PSRR so it takes a good PSU to make it sing.


----------



## Satellite_6

Hello, people who know much more than me. 
	

	
	
		
		

		
		
	


	



   
  I changed the tubes in my modest HiFiMAN EF2A DAC/AMP, it wasn't expensive, and it made a substantial improvement in the sound. Now I'm wondering about opamps. Is there a relatively cheap opamp that I can buy to give me a bit better soundstage and  instrument separation? The name of the DAC is PCM2702 if that matters.
   
  This might be to specific of a question, I'm just mildly curious. . .


----------



## qusp

if the 2702 is doing the actual DAC duties, I dont think youve got all that much hope IMO, its not great as a usb to spdif/i2s convertor let alone audio performance. but I suppose tere could be marginal improvement had, there isnt much we can do without knowledge of what the opamp is you want to replace


----------



## qusp

Quote: 





leeperry said:


> as much as I find AD797B impressive, I find it boring and its SS too colored...it's got that amazing SS depth, but it's too predictable and clearly doesn't exist in the record.
> 
> LT1028ACN8 is too cranky, so LT1363CN8 is as good as it gets for me. The tighest bass I've ever heard and more details than any phone could possibly output. It's got a low PSRR so it takes a good PSU to make it sing.


 

 can you please explain what a 'predictable soundstage' is? sounds like a nonsense term to me. first time I think ive heard the 797 SS described as too colored. personally I disagree and I find it hard to reconcile the word coloured with one of the lowest noise opamps of the last decade


----------



## Sebhelyesfarku

Quote: 





qusp said:


> can you please explain what a 'predictable soundstage' is?


 

 It's the opposite of the unpredictable soundstage.


----------



## leeperry

sebhelyesfarku said:


> It's the opposite of the unpredictable soundstage.


 
  what the man said 
	

	
	
		
		

		
		
	


	



   
  THD doesn't mean jack, otherwise we'd all be using LME49722.


----------



## ecclesand

Quote: 





qusp said:


> can you please explain what a 'predictable soundstage' is? sounds like a nonsense term to me. first time I think ive heard the 797 SS described as too colored. personally I disagree and I find it hard to reconcile the word coloured with one of the lowest noise opamps of the last decade


 

 I prefer opamps that color the soundstage with a hint of indigo.


----------



## Satellite_6

Quote: 





qusp said:


> if the 2702 is doing the actual DAC duties, I dont think youve got all that much hope IMO, its not great as a usb to spdif/i2s convertor let alone audio performance. but I suppose tere could be marginal improvement had, there isnt much we can do without knowledge of what the opamp is you want to replace


 


  It sounds great to me! Maybe I can find out what the opamp is. . .


----------



## qusp

Quote: 





leeperry said:


> what the man said
> 
> 
> 
> ...


 


  haha can you explain what an unpredictable SS is?? i'll tell you whats a joke.....
   
  if your SS is jumping around i an unpredictable manner, I think you got some worries that cannot be solved here at this forum. SS should be what is recorded at the venue or envisioned in the minds eye of the creator. if it does anything else but that, that is what i would call coloured


----------



## qusp

the thing is, you say that THD means jack, yet you are recommending what is essentially an instrumentation amplifier. its a fantastic chip, I dont disagree with that, but it seems to fly in the face of your argument to recommend an even more technically sound chip, even if its massively wideband behavior does need some coaxing to behave in the range we want it to. somewhat like another chip I know of....


----------



## leeperry

ecclesand said:


> I prefer opamps that color the soundstage with a hint of indigo.


 

 Don't start Andrea and MadMax on opamp coloring...they find LT1677 white sounding, I think I can hear that. 
   


> Originally Posted by *qusp* /img/forum/go_quote.gif
> 
> 
> haha can you explain what an unpredictable SS is?? i'll tell you whats a joke.....
> ...


 

 To my ears and each time I've rolled AD797B, the Z axis always sounded artificial and made up:




   
  It's predictable and colored in the sense that AD797B always makes the sound very lively on the Z axis...but after having rolled many opamps, I strogly believe that it's all made up and not in the recordings whatsoever.
   
  I also found the LT1028ACN8 SS triangular shaped, great stuff on headphones...but very colored too. And I've never heard such good low end bass tightness as on LT1363...to me it's the king of PRaT, no less. And its 60mA output allows it to drive headphones easily. Slash47 said that LT1363/4 were his fav. opamp, it's also a long time favorite of many rollers.
   
  Andrea finds its mids too thin-sounding, sort of "jaded" and lacking articulation...that's definitely how it sounded to me fed from a crappy soundcard. Its PSRR is low, it need clean power IME.
   
  And anyway, blind opamp rolling is a terrible idea...and you know it


----------



## Mad Max

797 sounds colored to me as well.  Think Tang with bit of blood mixed in.  
	

	
	
		
		

		
		
	


	



  I don't know about the soundstage, I rarely use it.
  It sucks the soul out of the music somehow.  That's a gargantuan _NO_, otherwise I would like it.
   
  What opamps make the SS indigo-colored?


----------



## ROBSCIX

Quote: 





mad max said:


> 797 sounds colored to me as well.  Think Tang with bit of blood mixed in.
> 
> 
> 
> ...


 

 Your opamp is only partially responsible for what you hear.  Some opamps are a better match with certain DAC's and circuits.
  The AD797 is like other opamps, some like it, some do not and some keep flip flopping back and fourth.


----------



## Satellite_6

The op amp in my EF2A is called LM833N which can be had on amazon for $3, wow that's cheap. Any advice regarding my previous question?


----------



## dlaloum

Quote: 





mark2410 said:


> btw anyone wouldnt know of a reasonable and cheapish desktop amp that could be used primarily for testing opamps, you know nice and easy to get to and swap out.


 


  Depends on what you mean by cheap...
   
  I got my M-Stage for US$249 (Lehmann Black Cube Linear cousin...)
   
  It has a good PSU (which means you can try opamps that have a poor/low PSRR) - it has a Class A no feedback discrete buffer stage, so it can handle pretty much most things out there, and has few opamp stability problems...
   
  The vendor also supplies a class A opamp socket mod as well as OPA627 on a twin card very cheaply
   
  So for a budget of around say US$300 you can have a versatile (and good sounding) amp, as well as a bunch of opamps, sockets, adapters to try out. (which is what I have done.... my try out collection has in it 797, 2604, 627, 637, 47920, 49860, 2111, 228....)
   
  I am currently listening to OPA637 biased in Class A
   
  Will switch to a different opamp tonight - not sure which yet


----------



## leeperry

mad max said:


> What opamps make the SS indigo-colored?


 

 OK, what color is LT1363? I'd say brownish-red hah!


----------



## ROBSCIX

Quote: 





satellite_6 said:


> The op amp in my EF2A is called LM833N which can be had on amazon for $3, wow that's cheap. Any advice regarding my previous question?


 

 Alot of gear will comes with cheaper opamps or generic units.  You can usually improve your sound or dial it in more to your personal taste with an opamp upgrade.


----------



## qusp

Quote: 





leeperry said:


> Don't start Andrea and MadMax on opamp coloring...they find LT1677 white sounding, I think I can hear that.
> 
> 
> To my ears and each time I've rolled AD797B, the Z axis always sounded artificial and made up:
> ...


 

 this sentient quality you attribute to the chip is a bit silly dont you think? an opamp cannot 'make up' anything. much more likely it just doesnt suit your circuit. I didnt and dont recommend 'rolling' blind. the amps I do any rolling in have the ability to add components in the feedback loop or power supply easily and so if I change chips then the surrounding circuit changes too. the adapters I use allow decoupling directly on the adapter and feedback capacitance and RC values easily changed. 
   
  that being said, the 797 went into the FiQ and hasnt left apart from a few holidays including now I am using OPA1641 with great results, but even that i'm not using much at all since for headphones I use mainly discrete sand based voltage follower circuits these days, aside from my portable sabre dac which i'm still deciding between 2 fully differential chips, OPA1632dgn and THS4150ID not so many choices for fully dif chips


----------



## Mad Max

Quote: 





leeperry said:


> OK, what color is LT1363? I'd say brownish-red hah!


 

 I hear it brownish green.  LT stuff tends to sound green.


----------



## qusp

synesthesia??


----------



## leeperry

qusp said:


> an opamp cannot 'make up' anything. much more likely it just doesnt suit your circuit.


 

 Opamps mess w/ the SS. the SS is completely different between LT1028ACN8 and LME49720NA...they both color it to death in their very own way. It might be due to improper designs, not arguing about that...blind rolling has its risks.


----------



## Nightslayer

Anyone has opinions on JRC opamps? I have the JRC2068DD and pre-burn in it sounds fuller than the OPA2227 that I used to put in my amp.. :/ Any notes on what burn-in of opamps does to soundstage? Pardon the sheer ignorance of the poster, if you please


----------



## Avro_Arrow

Japan Radio Company had some pretty good op amps twenty years ago.
  Unfortunately they have not progressed much since...


----------



## qusp

Quote: 





nightslayer said:


> Anyone has opinions on JRC opamps?


 


  Meh.....
   
   
  @ Leeperry i'm freezing a moment in time, we might actually at this very moment on this very subject...be on the same page.......
	

	
	
		
		

		
			





 of course I agree that the act of changing a technically good and otherwise sound opamp into a circuit built for something else without modifying it to suit the new opamp (and really we should include the headphones in this circuit depending on the design) this can for sure effect the subjective effect of the SS..there Ha i'm not about to start characterizing the SS with a colour though.....


----------



## ROBSCIX

Quote: 





qusp said:


> this sentient quality you attribute to the chip is a bit silly dont you think? an opamp cannot 'make up' anything. much more likely it just doesnt suit your circuit. I didnt and dont recommend 'rolling' blind. the amps I do any rolling in have the ability to add components in the feedback loop or power supply easily and so if I change chips then the surrounding circuit changes too. the adapters I use allow decoupling directly on the adapter and feedback capacitance and RC values easily changed.
> 
> that being said, the 797 went into the FiQ and hasnt left apart from a few holidays including now I am using OPA1641 with great results, but even that i'm not using much at all since for headphones I use mainly discrete sand based voltage follower circuits these days, aside from my portable sabre dac which i'm still deciding between 2 fully differential chips, OPA1632dgn and THS4150ID not so many choices for fully dif chips


 

  
  Let's have a peek at your adapters?


----------



## ROBSCIX

Quote: 





nightslayer said:


> Anyone has opinions on JRC opamps? I have the JRC2068DD and pre-burn in it sounds fuller than the OPA2227 that I used to put in my amp.. :/ Any notes on what burn-in of opamps does to soundstage? Pardon the sheer ignorance of the poster, if you please


 

 Most units found in todays components are considered generic but they can provide some great measurments.


----------



## qusp

the adapters are just the ones I posted earlier in the thread from sjostromaudio, who has designed a new version too I believe. the singles have something like 8 positions for multiple supply bypass, the feedback stuff isnt on the adapter, the surrounding circuits of the fiquest have been specifically designed with extra pads and loops with a very good quality PCB to make for easy modding, then there are a number of dip switches that allow you to choose which loop is in use. for instance placement bandwidth limiting and compensation for the 797 (or similar, but 797 in particular) was designed right into the amp, as with options for the OPA637


----------



## Sebhelyesfarku

Quote: 





leeperry said:


> t...blind rolling has its risks.


 

 Is it like blind dating?


----------



## leeperry

qusp said:


> the adapters are just the ones I posted earlier in the thread from sjostromaudio


 

 Adapters matter a lot IME...AD797BR and LT1363CS8 sounded far better off genuine browndogs than cheapish chinese adapters, where they sounded thinner and less clear.
  


sebhelyesfarku said:


> Is it like blind dating?


 

 something like that


----------



## Satellite_6

Quote: 





robscix said:


> Alot of gear will comes with cheaper opamps or generic units.  You can usually improve your sound or dial it in more to your personal taste with an opamp upgrade.


 


  Are op amps all the same kind? Any specific recommendation? The different tubes I bought changed the sound sig completely, in a good way: now the sound is now fairly muscial/dark sounding rather than the opposite. I'm not really looking for a different sound sig but a small general improvement esp. in soundstage/seperation if possible. . .
   
  Thanks. . .


----------



## qusp

browndogs are kinda crap IMO


----------



## leeperry

got anything better to propose? I tried those, and despite all the commercial bs (there used to be) on his listing they sounded horrid.
   
  there's also these ones, but his singles>dual DIP8 are not symetrical and the traces to both opamps don't have the same length, huh.
   
  there also was a diyaudio.com member selling his own, but only in big quantities....which I had no use for if they ended up not sounding as good as the browndogs.


----------



## ROBSCIX

Quote: 





qusp said:


> browndogs are kinda crap IMO


 

 Yeah, I always thought they were not that good.  Very weak designs and build quality.  I have been considering just designing some for those interested in audio work.  Maybe I will have a look at those ones you linked to, although I am pretty sure I have tried them before.  I guess it is time to pull out the PCB design software.


----------



## qusp

yep the ones from Peranders of sjostromaudio.com  ADP01, ADP02, ADP03 are the ones I use. the ones Leeperry is talking about with the GB on DIYA are his latest ones, which I havent tried yet as I have a fair few of the last version left. there is also a new one at digikey that looks quite good, nothing in the way of extra functionality, but very short traces, shortest i've seen. the peranders GB was selling sheets of 25, but you would get a sheet for about the price of 3 browndogs, so frankly i dont see your argument, who cares if you dont like them and have extras when they only cost you as much as a few BD? but I can say that unless you have problems in the head and/or dont know how to use the extra features the adapter should not have any 'sound' at all. its simply a square cm of FR4 with gold plated traces, pads for decoupling and holes where the pins go, which you can chose to use how you wish, I use cryo silver pins that I make out of wire, or wire them directly into perfboard mockup designs.


----------



## leeperry

well, his adapters can't do 2 single DIP8 > dual DIP8 so the browndogs still remain my best option. Seriously, the traces to both opamps are not the same length on this one, this can't be good.
   
  and I find it rather sarcastic to question my mental sanity when you're using cryo silver pins on your adapters..just sayin'


----------



## ROBSCIX

Quote: 





qusp said:


> yep the ones from Peranders of sjostromaudio.com  ADP01, ADP02, ADP03 are the ones I use. the ones Leeperry is talking about with the GB on DIYA are his latest ones, which I havent tried yet as I have a fair few of the last version left. there is also a new one at digikey that looks quite good, nothing in the way of extra functionality, but very short traces, shortest i've seen. the peranders GB was selling sheets of 25, but you would get a sheet for about the price of 3 browndogs, so frankly i dont see your argument, who cares if you dont like them and have extras when they only cost you as much as a few BD? but I can say that unless you have problems in the head and/or dont know how to use the extra features the adapter should not have any 'sound' at all. its simply a square cm of FR4 with gold plated traces, pads for decoupling and holes where the pins go, which you can chose to use how you wish, I use cryo silver pins that I make out of wire, or wire them directly into perfboard mockup designs.


 

 I may grab a few or look through my collection, I seem to think I have a few around here.  I like the extra tracing for the Caps..etc.  I was going to include such ideas on my adapters, if I ever get around to making them.


----------



## qusp

Quote: 





leeperry said:


> well, his adapters can't do 2 single DIP8 > dual DIP8 so the browndogs still remain my best option. Seriously, the traces to both opamps are not the same length on this one, this can't be good.
> 
> and I find it rather sarcastic to question my mental sanity when you're using cryo silver pins on your adapters..just sayin'


 

 he has 2 x single soic8 to dual dip8, he also has a soic16 adapter for some rare intrumentation amps. why bother with dip8 anyway? most decent new chips arent even made in dip anymore
   
  hey look I saw your silly looking bursons before you decided to change your mind yet again, I just happen to have an abundance of silver wire around here, its more available to me than anything else the right size and given the need to add pins to the adapters, I would much prefer to add high purity silver pins that solder in directly that cost me a matter of 20c in materials than those stupid overly bulky dip pin sets with 2 way pins made of brass or something. I think I have perfectly valid reasons for questioning your views; where the above is just a matter of quality and availability. I mentioned nothing about it changing the color of my music. what would be crazy would be spending more for crap pinheaders and postage when I have better quality (in every way) materials in my workshop that cost me less. 1 adapter might use about 2-3cm of wire.


----------



## leeperry

qusp said:


> why bother with dip8 anyway?
> [..]
> I saw your silly looking bursons before you decided to change your mind yet again


 
   
  let's see...because the "AC" grade of LT1028 doesn't exist as SOIC8? The lower "C" grade sounds a lot worse in many ppl's opinion(including mine).
   
  oh, silly looking...I guess you've never heard the Burson V2, duh 
	

	
	
		
		

		
		
	


	



   
  I can't use them in my current DAC because its linear regulated PSU isn't beefy enough...but I think I'll grab that Burson DAC down the road anyway.
   
  I wish you good luck w/ your non-silly cryo silver pins then


----------



## ROBSCIX

For proper information for the thread, the LT1028 is available in SOIC8...the LT1028ACN8 denotes a specific model which is Dip8.
  Look for the LT1028CS8..that is a SOIC8 IC.
   
  Check out the spec sheets they can help:
LT1028


----------



## qusp

I use soic8 LT1028 in my bipolar coffin minigold super regulator, seems you dont read datasheets. I have 6 burson V2 here and none of them in use. I seem to remember you saying they were coloured to hell and wouldnt go near them anymore. they are nice enough, but simply not stable enough for my purposes, I prefer not to have to adjust my opamps when conditions change, due to liking DC coupled designs
   
  you really should read the datasheet, they provide all manner of useful info.......


----------



## leeperry

You've recently gained a place on my ignore list, so I unfortunately can't read your post in full...but LT1028AC -its higher and noticeably better sounding grade- only exists as N8 and not S8.
   
  Maybe I'm not the one who can't read a datasheet after all


----------



## qusp

thats funny, somebody informed me that you have stuck your fingers in your ears, you only recently came off my ignore list after being there for quite some time. the huddler change reset all of those settings and you havent annoyed me enough to reinstate it till recently, since I havent really been here much since the change. it really was much more peaceful, so maybe i'll just reinstate that, I know you wont be able to resist taking a peak and I know that given your number of edits you only just came up with this reason just now. its laughable that you think you can hear the difference between the 2 grades, the typical performance specs are effectively identical unless you claim to be able to hear into the uV and nA range. and the thing is, you said the 1028 wasnt available in soic8, which makes me think that you only just now read the datasheet and found your way out. how can you have made an informed decision between one thing you didnt know existed and another you did?
   
  see the thing is, what difference does it make, you dont listen to anyone anyway, the point at which you pulled out speaks volumes
   
  and i think you'll find that the grades read down the page, with milspec at the bottom. A and C mean zero towards quality grading, it simply denotes the package type


----------



## Sebhelyesfarku

Ok, who's on whose ignore list? I got confused.


----------



## SpudHarris

No love lost betwenn them two haha.
   
  That said, I've had dual soic LT1028 for ages and never really found a circuit where they shone. My Fi-Q which isn't as modded as Qusp's is astounding with AD797BRZ's. I did have the AD797ARZ's in there but there's a billion miles between the two and frankly I might as well have been listening with an LF353 in there so I went with the higher grade  
	

	
	
		
		

		
		
	


	




 .


----------



## leeperry

LT1028CS8 sound horrid compared to ACN8, I could DBT them from the other side of the street. I wonder why ppl w/ tin ears try rolling opamps tbh...cryo silver or not


----------



## dlaloum

Quote: 





leeperry said:


> LT1028CS8 sound horrid compared to ACN8, I could DBT them from the other side of the street. I wonder why ppl w/ tin ears try rolling opamps tbh...cryo silver or not


 

 It is the synergy it generates with the tin....


----------



## SpudHarris

Quote: 





leeperry said:


> LT1028CS8 sound horrid compared to ACN8, I could DBT them from the other side of the street. I wonder why ppl w/ tin ears try rolling opamps tbh...cryo silver or not


 
   
  Of course you could  
	

	
	
		
		

		
		
	


	




  and don't let Dorothy hear you say that!!


----------



## leeperry

spudharris said:


> Of course you could
> 
> 
> 
> ...


 

 I'm not from an english speaking country, I dunno anyone called Dorothy...is she your night nurse or something? And yes, the C/AC grade difference of LT1028 is well documented: http://www.head-fi.org/forums/f6/audio-gd-discrete-op-amps-reviewed-OPA-earth-OPA-moon-OPA-sun-v-2-a-397691/
   
  C truly sounded horrid each time I tried it


----------



## ROBSCIX

Quote: 





spudharris said:


> No love lost betwenn them two haha.
> 
> That said, I've had dual soic LT1028 for ages and never really found a circuit where they shone. My Fi-Q which isn't as modded as Qusp's is astounding with AD797BRZ's. I did have the AD797ARZ's in there but there's a billion miles between the two and frankly I might as well have been listening with an LF353 in there so I went with the higher grade
> 
> ...


 

 They are OK when used in certain designs.  The AD797's seem to have a following but they can be unstable in some situations also.
  I am actually building some dual AD797BR's from some associates.  Nice adapters, Cardas Quad solder...they should be some nice modules.


----------



## i_djoel2000

greetings all..
   
  i wanna try order some sample from texas instrument. but when i register and they require me to put office phone number, they keep saying the number is not valid eventhough that number ACTUALLY IS!!
   
   
  anybody can help me with this matter? thanx in advance. oh, if this is matter..i live in Malaysia. thanx


----------



## jageur272

Quote: 





leeperry said:


> I'm not from an english speaking country, I dunno anyone called Dorothy...is she your night nurse or something? And yes, the C/AC grade difference of LT1028 is well documented: http://www.head-fi.org/forums/f6/audio-gd-discrete-op-amps-reviewed-OPA-earth-OPA-moon-OPA-sun-v-2-a-397691/
> 
> C truly sounded horrid each time I tried it


 

  
  Wait... That's well documented?  A single review that is entirely based on his opinion?  Gee...  DBT's are VERY rarely ever performed for audio; don't expect to do one properly at your residence.


----------



## leeperry

i_djoel2000 said:


> i wanna try order some sample from texas instrument. but when i register and they require me to put office phone number, they keep saying the number is not valid


 
   
  fill in numbers until it's happy, I don't recall having problems w/ that.
   


jageur272 said:


> Wait... That's well documented?  A single review that is entirely based on his opinion?  Gee...  DBT's are VERY rarely ever performed for audio; don't expect to do one properly at your residence.


 

 But you didn't hear the chips...so what are you arguing about exactly. Gee...


----------



## SpudHarris

Quote: 





leeperry said:


> I'm not from an english speaking country, I dunno anyone called Dorothy...is she your night nurse or something? And yes, the C/AC grade difference of LT1028 is well documented: http://www.head-fi.org/forums/f6/audio-gd-discrete-op-amps-reviewed-OPA-earth-OPA-moon-OPA-sun-v-2-a-397691/
> 
> C truly sounded horrid each time I tried it


 
   
  You know Dorothy!
   
  You know, the Wizard Of Oz - You said I had Tin Ears  
	

	
	
		
		

		
		
	


	




 Geez, it's not funny when you have to explain it......


----------



## jageur272

Quote:


leeperry said:


> But you didn't hear the chips...so what are you arguing about exactly. Gee...


 

  
  I thought you heard music, not chips.  English doesn't have to be my first language for me to understand that.


----------



## qusp

neither did you..... do you actually read what you write in your posts? you claimed there WAS NO soic8 version on the previous page and now you are claiming you did listening tests comparing the soic8 and DIP8........


----------



## leeperry

jageur272 said:


> I thought you heard music, not chips.


 

 I listen to the opamps more than to the music sometimes....just like boring movies make me see rainbows on my DLP pj. With exciting movies, I never see any. Boring movies also make me rave at my perfect D65/2.4/SMPTE-C calibration and uber 24p Reclock smoothness....I don't think you can take apart the content and the container so easily, actually you can't.
   
  I've compared LT1028CS8 and LT1028ACN8 on different kind of adapters, just like I've compared pretty much all the opamps in majkel's list...and then some. Some ppl can't hear any diff between opamps -even w/ cryo silver pins it seems-, they should be happy as ignorance is bliss...it really is.
   
  I wish I never got diagnosed w/ this nasty Andrea'itis...but well, it's fun I love it. You just need to learn that all good things come to an end...after listening to +50 different opamps, you REALLY need to pick your favorite...otherwise you'll keep looking for something that does not exist. There's no perfect opamp, they're all made of compromises. Otherwise I'd pick the LT1363 tight bass and non-shrill trebles, a mix of the LT1028AC/AD797B SS and the Burson V2 mids 
	

	
	
		
		

		
		
	


	



   
  That's the beauty of the gear that has several opamps in a row, you can use AD797B as LPF-I/V and LT1028AC/Burson V2 as final buffer. This is a combo made in heaven...the HD2 was astounding w/ those!


----------



## SpudHarris

I thought I was done with rolling here since getting into exotic tubes but I just thought I'd see if the LT1363 was how I remember it. I settled on the OPA2111AM in my P3+ about 8 months back so know the signature intimately and never really wanted anything more. I dropped the 1363's in tonight and am listening as I write this, I have to say that I'm liking what I'm hearing.
   
  I know that the signature is new at this point but it's nice enough for me to want to know it better. I will keep them in for now and report back after a couple of weeks listening. It may be that I was just bored with the same signature but I think the LT1363 does have something......


----------



## Satellite_6

I've done some googling and OPA 2134 or OPA 2132 are supposed to be upgrades for OPA 2604, which is the one in my amp. Any advice on which one + where to buy? If they're not expensive I'll give them a try.
   
  heh, that ryhmes. . .


----------



## Avro_Arrow

Just get the OPA1642, it's the replacement for OPA2134.
  Sounds much nicer too.
   
  Or, if you really want a slammin' chip, LT1364 is the way to go.
   
  Digi-key has lower shipping charges on small dollar orders.
   
  Quote: 





satellite_6 said:


> I've done some googling and OPA 2134 or OPA 2132 are supposed to be upgrades for OPA 2604, which is the one in my amp. Any advice on which one + where to buy? If they're not expensive I'll give them a try.
> 
> heh, that ryhmes. . .


----------



## dlaloum

I got mine on fleabay...
   
  But the opa2604's biggest weaknesses are 1) Likes higher voltages (speed and bandwidth apparently improve at +/- 18V and Get even better at +/-22V) 2) has low PSRR - ie it requires a very clean power supply (any ripple/ noise in the PSU will likely have a noticeable influence)
   
  The 2134/2132 has a High PSRR - so less affected by PSU - and is optimal at 15V
   
  But there are lots of opamps that are claimed to sound better.
   
  I have replaced my OPA2134 with OPA627, OPA637, LME49860, AD797 - all of which sounded better (all biased into class A with resistor mod, in a Matrix M-Stage)
   
  I also have a 2604 based amp (Cute Curve)- which sounds very good when run with a high quality PSU (0.25mV ripple) but still not as good as the M-Stage... I intend at some stage to experiment with opamp upgrades on that as well....


----------



## igor0203

My favorite opamps so far are LME49720HA and LT1028ACN8. I'm using Club3D Theatron Agrippa 7.1DTS with DIY preamp, TK2050 amplifier and modded Indiana Line Arbour 5.06.
  In my setup I found that LT has slightly more emotions, more liquid mids than LME but on the other hand LME has a little better highs and bass and provide slightly more realistic imaging.


----------



## Satellite_6

Well, now I have too many choices. . . >_<
   
  I guess I'll go with the slammin' LT1364. 
	

	
	
		
		

		
		
	


	



   
  When I do a search on Digikey it gives me a bunch of results tho. . . which one?


----------



## Avro_Arrow

This one.
   
  Quote: 





satellite_6 said:


> Well, now I have too many choices. . . >_<
> 
> I guess I'll go with the slammin' LT1364.
> 
> ...


----------



## Satellite_6

Thanks


----------



## leeperry

satellite_6 said:


> I'll go with the slammin' LT1364.


 

 In many ppl's experience, two single opamps on an adapter sound much better than a dual.
   
  even TI acknowledged the problem, but didn't really fix it: http://focus.ti.com/docs/prod/folders/print/opa1612.html
   
_"The dual version features completely independent circuitry for lowest crosstalk and freedom from interactions between channels"_
   
  We don't solder them on adapters for the hell of it, and besides I very much pretty to solder DIP8's than SOIC8's....much easier.


----------



## Satellite_6

Quote: 





leeperry said:


> In many ppl's experience, two single opamps on an adapter sound much better than a dual.
> 
> even TI acknowledged the problem, but didn't really fix it: http://focus.ti.com/docs/prod/folders/print/opa1612.html
> 
> ...


 

 That's good to know I guess, I think I'm too lazy to do anything but but switch out parts in my little amp tho.


----------



## Aynjell

Quote: 





spudharris said:


> ...
> 
> 
> Favourites


 
  Oh that's just geek porn right there.


----------



## dlaloum

Yes - but in my opamp measurements with RMAA, I believe (very strongly) that I am seeing increased crosstalk due to the adapters, along with increased IMD...
   
  So the design of the adapter is absolutely critical - path lengths need to be eve and so does the shielding of paths from interference etc.... (especially given the paths are now longer and more exposed)


----------



## leeperry

dlaloum said:


> but in my opamp measurements with RMAA, I believe (very strongly) that I am seeing increased crosstalk due to the adapters, along with increased IMD...


 

  using internal soundcards? surely the browndogs will pick up interferences there. As far as I know, you don't care for IMD in a playback device.


----------



## Avro_Arrow

That's good to know, but taking a SOIC chip, soldering it to an adapter and sticking it in a socket to boot
  just destroys any sonic quality the chip might have had in the first place...

  
  Quote: 





leeperry said:


> In many ppl's experience, two single opamps on an adapter sound much better than a dual.
> 
> even TI acknowledged the problem, but didn't really fix it: http://focus.ti.com/docs/prod/folders/print/opa1612.html
> 
> ...


----------



## leeperry

avro_arrow said:


> taking a SOIC chip, soldering it to an adapter and sticking it in a socket to boot just destroys any sonic quality the chip might have had in the first place...


 
   
  Talking from personal experience I'm sure...


----------



## Mad Max

Quote: 





avro_arrow said:


> That's good to know, but taking a SOIC chip, soldering it to an adapter and sticking it in a socket to boot
> just destroys any sonic quality the chip might have had in the first place...


 

 So soldering it in should make an incredible day-and-night difference with it?


----------



## Sebhelyesfarku

Quote: 





satellite_6 said:


> I guess I'll go with the slammin' LT1364.


 

  I've put an LT1364 into my headphone amp in the place of an NE5532 but haven't got "night and day" differences, to put it mildly. Probably because it's only in the input stage, the amp is discrete class A. Amps fully based on opamps can realize bigger improvements, I guess. Or I'm simply deaf...


----------



## Avro_Arrow

Well, if you mean it can make the difference between it sounding good and not working at all,
  then I guess it can make a big difference. Just try putting an OPA690 in a socket...
  Don't get me wrong, I too use adapters and sockets and so on...I just know I am presenting
  the op amp with a less than optimal situation. The final circuit is always proven with the
  op amps soldered directly in whether it is DIP or SOIC.
  
  Quote: 





mad max said:


> So soldering it in should make an incredible day-and-night difference with it?


----------



## Avro_Arrow

When you are rolling op amps, there is never any guarantee that any particular op amp is always
  going to perform well, you are presenting it with a circuit that was not designed for it.
  LT1364/LT1363 are fast op amps. If you put it in a circuit where the other components are not
  as fast then it will not make _as much_ difference.
   
  You have to consider a circuit as a whole to understand what will work and what will make a difference.
   
  Quote: 





sebhelyesfarku said:


> I've put an LT1364 into my headphone amp in the place of an NE5532 but haven't got "night and day" differences, to put it mildly. Probably because it's only in the input stage, the amp is discrete class A. Amps fully based on opamps can realize bigger improvements, I guess. Or I'm simply deaf...


----------



## dlaloum

Quote: 





leeperry said:


> using internal soundcards? surely the browndogs will pick up interferences there. As far as I know, you don't care for IMD in a playback device.


 


  No actually - running in either of a Matrix M-Stage (Diamond Buffer discrete class A buffer stage, class A opamp operation with 3.9k res @ +/- 15V) - or in a Firestone Audio Cute Curve (also biased into class A for the opamp using the same resistor but at +/- 12V )
   
  All cables to from sources have chokes fitted to stop RF getting through and polluting things - tests were initially baselined in loopback to check what internal noises were Soundcard generated (M-Audio 2496).
   
  The IMD is being generated by the Headphone amps circuitry and particularly by the opamps - with substantial differences between them - and particularly noticeable increases with adapters whether soldered or socketed ones. 
   
  IMD is considered by many to be the nastiest (or one of the nastiest) and most audible form of distortion and the one that it is most critical to reduce - typical Valve amps that sound great often have terrible THD but good IMD specs. Also much pleasant colouration is due to harmonics - ie THD - and preponderance of even order harmonics (which is part of THD)
   
  From Stereotimes article http://www.stereotimes.com/DAC120709.shtml reviewing the BelCanto DAC (they are talking here about the analogue circuits :

"Inter-modulation distortion is a standard test measurement of audio performance. REF1000 amplifiers, for example, are rated at 0.0007% IMD (CCIF) at one watt into 4 ohms, using 14:15KHz tones. IMD occurs due to circuit nonlinearity and sounds especially harsh and unpleasant because it is not _harmonically related_ to the audio signal. "........."The same thing happens with those spurious high frequencies I'm calling _noise_, they inter-modulate one another and generate products that can fall within hearing range. These products are very low level, they are random, they are unrelated to the music, they are virtually impossible to measure with certainty and accuracy (partly due to the noise floor of the test equipment), but their effects are audible. How do I know? Because their reduction in the DAC3VB produces an audible change. "


----------



## dlaloum

Quote: 





avro_arrow said:


> That's good to know, but taking a SOIC chip, soldering it to an adapter and sticking it in a socket to boot
> just destroys any sonic quality the chip might have had in the first place...


 

 Well that would be "gilding the lilly" a little bit...
   
  The socket/adapter is undesirable and can potentially introduce various problems (RFI, Phase delay due to differing trace lengths, etc...) but a really good chip in an adapter/socket will usually still sound better than a bad one  soldered into place.... its just that it could sound even better if it were soldered into place rather than socketed and mounted on an adapter.
   
  Next question is - How much better.... well that can be measured - lots of things can be quantified - THD, IMD, Freq resp, rise time, etc... can all be quoted......
   
  Final question - What is that difference worth to you?    heheheh 
	

	
	
		
		

		
		
	


	




  Some people would sell their souls for another 0.001% reduction in IMD....


----------



## sw98

Random question, but is there any difference in soundstage or SQ between the LME49720 and LME49720NA?


----------



## qusp

Quote: 





dlaloum said:


> Final question - What is that difference worth to you?    heheheh
> 
> 
> 
> ...


 


  I sure would if I thought it was still worth anything 
	

	
	
		
		

		
		
	


	



   
  totally with you here and adapters do not have to be such a bad thing if they are well made, for sure I would still take an OPA827 in soic8 over OPA134 in dip8, in a second.
   
  sw98: IMO no, none at all, i'm sure someone will pipe in and say its a night and day difference and that I must have woolen ears and that immeasurable differences are plain as day with their golden ears.
   
  yes I have both, yes I use the can if any, but that is more about my neurosis than anything else. that being said, although it measures well, its boring as hell IMO and I never do. its popular as a buffer or in dac IV stages because of its measured performance and the fact its unity gain stable, but I just find it sucks all the life out of the music...... insipid is a word that comes to mind
   
  LME49710 is excellent in regulators though, you might try checking out some of the more modern national chips like the LME49722 and tell us how it goes, has even better spec


----------



## sw98

Thanks for your help! I'm purchasing a new Essence ST that comes with 2 LME479720NA's, so if there's no difference to the LME49720 then I'll just pop in the NA's.


----------



## igor0203

Try LT1028ACN8


----------



## Mad Max

Quote: 





sw98 said:


> Thanks for your help! I'm purchasing a new Essence ST that comes with 2 LME479720NA's, so if there's no difference to the LME49720 then I'll just pop in the NA's.


 

 'NA denotes the plastic DIP8 version.  If you end up liking it, then you may like the metal can version even more (LME49720*HA*).


----------



## leeperry

igor0203 said:


> Try LT1028ACN8


 

 This one is hard to roll blindly...whatever in my Spitfire DAC or on the Prodigy HD2, it would make a loud crackling noise when my fridge motor turns on/off or someone turns off my bathroom neon...I also had it checked w/ an oscilloscope by a pro, and it was oscillating in the Mhz range. Clearly not for blind rolling IME.
   
  LT1363 is a far better candidate


----------



## dlaloum

Quote: 





leeperry said:


> This one is hard to roll blindly...whatever in my Spitfire DAC or on the Prodigy HD2, it would make a loud crackling noise when my fridge motor turns on/off or someone turns off my bathroom neon...I also had it checked w/ an oscilloscope by a pro, and it was oscillating in the Mhz range. Clearly not for blind rolling IME.
> 
> LT1363 is a far better candidate


 

 Well it sounds like the fridge motor is throwing out both a spike and additional RF noise.... and the Power Supply is not up to controlling it.
   
  So my take on that type of issue would be... regardless of the opamp this will have an impact (some more audible than others) - so first fix the PSU - and if the LT1028 is particularly sensitive to it - us it as your sensor, your "canary".
   
  1) Put something on the power line to absorb the spike (surge protector, power regulator, isolating transformer, regenerator or UPS) - pick your flavour and budget... but a common computer sine wave UPS can help (make sure it is a full sine wave version! otherwise it is nasty).
  2) Put some chokes on either end of your power cables (all power cables going into and out of ANY interconnected piece of equipment in your rig. (Once the noise is in there, it can pollute your ground and spread to other components via interconnects - even if the components are off)
   
  There are articles on the web about eliminating RF noise - also lots of articles from Ham Radio people (they suffer worse than Audio people do from RF issues... for obvious reasons - they are working within the RF bands!)
   
  Once the noise is eliminated from the LT1028 - then you can listen to see if you like to OPAMP, and you can try your other favourites - you may find they have improved....
   
   I just recently went through extensive choking of all in and out lines of my rig - and it has definitely helped! - I was previously getting some hash at low levels in my RMAA measurements (which helped me to identify the problem) - the chokes on all the lines have eliminated that - and grounding everything to a common ground has eliminated a low level hum problem as well - and on the RMAA graphs the harmonics of the 50Hz power have dropped to less than half what they were before. 
   
  Some say that the biggest gains in Audio quality all come down to power supply - both adequacy (enough in a timely manner when required) - and cleanliness.... they may be right.


----------



## murrays

Quote: 





dlaloum said:


> Well it sounds like the fridge motor is throwing out both a spike and additional RF noise.... and the Power Supply is not up to controlling it.
> So my take on that type of issue would be... regardless of the opamp this will have an impact (some more audible than others) - so first fix the PSU - and if the LT1028 is particularly sensitive to it - us it as your sensor, your "canary".
> 
> 1) Put something on the power line to absorb the spike (surge protector, power regulator, isolating transformer, regenerator or UPS) - pick your flavour and budget... but a common computer sine wave UPS can help (make sure it is a full sine wave version! otherwise it is nasty).
> ...


 

 Leeperry said his amp was oscillating in the RF range.  The stability problem must be addressed first before you even start to consider filtering external inputs. My amplifiers are stable and I do not even have shielding on my interconnects, let alone any chokes, filters, ferrites, etc.  The HF oscillation will colour the sound (IMD) and cause sensitivity to environmental phenomena. By the way, if it not done right, adding filters to trap/block noise can actually create more problems than they solve, even positioning can play a part. 
  HF noise spikes do not always enter by the power supply as you would expect; sometimes the coupling is via electrical ground, or air (EMI), or inductive coupling with wires in the walls or other nearby equipment.
  You are correct about grounding  - a good ground is very important, and needs careful attention.


----------



## qusp

yep, thats why due to everything in my system being DIY, I have floated all shield grounds tied to my plumbing. agreed on PSU quality though, until its sorted out everything else is coloured by it and nothing you will do with signal can stop that till its done. the opamp is oscillating because its a very wide bandwidth chip being used for lowly audio signals and as with all of its kind, it needs compensation in the feedback loop to address this,I think you'll find its in the datasheet, plus I mentioned it earlier


----------



## leeperry

dlaloum said:


> Well it sounds like the fridge motor is throwing out both a spike and additional RF noise.... and the Power Supply is not up to controlling it.


 

 Good point. But both the computer ATX PSU for the HD2 soundcard or the "Firestone Supplier" linear regulated PSU couldn't control it. Using a "Unity Gain Stable" opamp fixes the problem completely.


----------



## yiancar

Hey guys am new to the opamp trip.
	

	
	
		
		

		
		
	


	




 I am building a phono preamp where a Chopper stabilized DC-servo is used. Its based on a MAX420 but this chip stopped manufacturing right? As a replacement I found OP07. Any other suggestions?


----------



## Satellite_6

I don't suppose it's a good idea to pry the original op amp out at an angle. . . I can't take the EF2A completely apart without an allen key and I can only get at the adapter at an angle. 
	

	
	
		
		

		
		
	


	



   
  EDIT: I got it out without destroying it, does it matter which way the new one goes in?
   
  EDIT: nvm, I got it. 
	

	
	
		
		

		
		
	


	



   
  EDIT: Clarity has increased a bit with the LT1364 and the sound sig of my EF2A has become more analytical. . . now I have to get used to the sound sig all over again! I suppose if I end up not liking it I can try something else.


----------



## Pluto2

Speaking of oscillation, I recently installed some ADA4627-1s and opa827s in my circuit (+_15V), and noticed that the ADA chips got much hotter than the opa ones, though I understand the ADAs draw 2 mA more each, but, would it feel much hotter for a 210mW dissipation than a 150mW? actually it was a bit unbearable with a finger touch......
   
  I used to have LM4562s and opa2211s at the same locations but they were just warm....Can I assume there is no oscillation at the ADAs, given that LM4562 has higher GBW product than the ADA? Ah,....would the adaptors have something to do with it? I do have 0.01 uFs on the main board though but not very close to the adaptors. Thanks!


----------



## ROBSCIX

Who here is using any bypass caps on their opamps?
  If so what type of caps do you use?
  I have read varying opinion on this subject so figured I would ask you guys what you think...
  opinions?


----------



## jageur272

Quote:


robscix said:


> Who here is using any bypass caps on their opamps?
> If so what type of caps do you use?
> I have read varying opinion on this subject so figured I would ask you guys what you think...
> opinions?


 

  
  A decent quality polyprop or tantalum coupled with a ceramic should have all of your bases covered.  Using electrolytics as bypasses doesn't help at all.  I find that a 2.2uF polyprop with a .01uF good quality ceramic has been my modus operandi for the past few amps I've made.  Great results thus far.  I may add a 1uF tantalum on my next one.
   
  Adding bypass caps is vitally important if you want to preserve the high speed of the opamps which translates into better fidelity.  I am of the opinion that opamps sound different, but each circuit has a bigger change on the sound of an opamp than anything else.  The capacitance that it's driving, the topology of the circuit, etc. are more important than which adapter sounds better.  In fact, adapters are ALWAYS detrimental to the sound of an opamp, stray capacitance will always make the circuit less stable.
   
  But I digress.  Bypasses are important.  The smaller values should be placed as close to the pins as possible or right on them even if possible.  Bass seems tighter compared to unbypassed in a simple (cmoy-esque) circuit.


----------



## Mad Max

Noted.


----------



## Satellite_6

I think I'm going to have to go back to the original op amp in my EF2A. There is the possibility that what I'm hearing is just placebo or something but here it is. . .
   
  The bass sucks now! It has no omph and overall the sound isn't as dark. I loved the dark-ish, musical sound that the 5654 tubes gave me and now that's gone. It's even more noticeable when using the EF2A as just an amp and using my Cowon as the source. The i7 has never sounded so dry! The sound is marginally clearer I think but the sound sig doesn't go well with the HD 650s. To be fair, I don't think this is a bad thingmajob, it just doesn't go with the 650s. I'm not going to switch back right away but I think I will eventually. The difference is pretty small anyway I think, not the kind of improvement I got from rolling tubes.
   
  Any advice for a more "musical" sounding op amp? I might try another or decide to settle with the original.


----------



## leeperry

your EF2 runs off a wall wart, LT1363/4 has a low PSRR...it will not sound good.
   
  Try AD797B/LT1028AC/ADA4627-1B/OPA827/etc?


----------



## Satellite_6

Quote: 





leeperry said:


> your EF2 runs off a wall wart, LT1363/4 has a low PSRR...it will not sound good.
> 
> Try AD797B/LT1028AC/ADA4627-1B/OPA827/etc?


 

 Bummer, I guess that was a bad recommendation then?
   
  I will keep listening though.


----------



## murrays

Quote: 





leeperry said:


> your EF2 runs off a wall wart, LT1363/4 has a low PSRR...it will not sound good.
> 
> Try AD797B/LT1028AC/ADA4627-1B/OPA827/etc?


 

 That's not so much of a problem if the amp has good local regulation (does it?). Bear in mind that the LT1363 has a PSRR is 90 to 100 dB.
  A lot of the point of PSRR is not supply ripple rejection, but rejection of voltage changes due to reflection of the changing output current.
  If you're having to rely on really high PSRR because of large levels of noise and fluctuations at the power inputs then your circuit design is lacking.  Good power supply filtering and local HF bypassing will eliminate most of that.
  A good test is to measure (or even better - listen to) the AC voltages on the power supply pins of the op-amp. Ideally there should only be DC (zero hertz) but it can be a real eye-opener to find that you are feeding audio back into the power supply inputs.  Even a high PSRR won't block all of that.


----------



## Charminbaer

Hi, ive been reading your posts for a while now. Now i want to participate actively.
   
  I´ve got a question regarding AD797BR in a Matrix m-stage.
  I tried it and it sounded great but i got a feeling, that the longer i keep hearing the more distorted it sounds, especially in complex musical scenes.
  Could this be due to heat? Or is it just not stable? What can i do to stabilize it?
   
  I found this tutorial on stabilizing an AD797: http://www.acoustica.org.uk/t/naim/35clockreg.html
   
   
  Quote: 





> Between pins 6 and 8 we can connect a small capcitor (47pF) which closes an internal feedback loop and has the effect of reducing distortion by reducing output impedance dramatically at high frequency


 
   
  He also talks about some other tweaks but i dont know if they work for the m-stage circuit
   
  Since i am no engineer i dont know what he exactly talks about. Could someone here with greater knowledge explain to me what to do?
   
  Is there a way to get it stable without soldering something on the board itself? Something like just soldering a resistor to the legs of the opamp?
   
  I would be happy if someone could give me some advice on this.


----------



## dlaloum

Quote: 





charminbaer said:


> Is there a way to get it stable without soldering something on the board itself? Something like just soldering a resistor to the legs of the opamp?


 
  You can use the same method as used for the Class A mod - get a socket - do the soldering on the socket - plug the opamp into the socket and the socket into the board.
   
  This way if you make a mess - you toss the socket - no risk to the opamp or board, and sockets are cheap


----------



## Charminbaer

hi,
   
  yes i´ve  thought about that too , i also have some spare sockets.
  Isn´t this, in the tutorial mentioned mod, a Class A Bias ?
   
   
  PS:
   
  I played around with the DIP-switches and it seems that almost all stability issues are gone when set to +20db.


----------



## murrays

Quote: 





charminbaer said:


> Hi, ive been reading your posts for a while now. Now i want to participate actively.
> 
> I´ve got a question regarding AD797BR in a Matrix m-stage.
> I tried it and it sounded great but i got a feeling, that the longer i keep hearing the more distorted it sounds, especially in complex musical scenes.
> ...


 
   
  I recommend Tangent's website, which has a good write-up on dealing with "cranky" op-amps http://tangentsoft.net/audio/hs-opamp.html.  If you find it difficult to understand you may need to search out some op-amp tutorials to fill in some of the basics.


----------



## murrays

Quote: 





charminbaer said:


> I played around with the DIP-switches and it seems that almost all stability issues are gone when set to +20db.


 
   
  I presume that was an increase in gain.  That is one established way of improving stability. 
  The only real downside is that it may reduce the usable range of your volume control.


----------



## qusp

yep, compensation and bandwidth limiting are often needed to help the 797 cope with lower audio frequencies and lower gain. 797 works quite well with class A bias, but it doesnt always benefit many modern chips, as they are mostly designed to work in class A as it is.
   
  loving THS4150 at the mome (fully differential chip) this range of chips contains much of the same circuitry as the discrete solid state Pass Labs super symmetry (SUSY) designs, so much so that they had to buy a license from Nelson in order to use it. handy little group of chips, the VCOM pin servos the output to the voltage applied to it, easy offset adjustment. they will also directly take a single ended input with the - signal pin tied to ground and output fully balanced audio
   
  but most importantly, it sounds excellent!! no grain, slams like a mofo and dynamics for miles


----------



## dlaloum

Quote: 





qusp said:


> yep, compensation and bandwidth limiting are often needed to help the 797 cope with lower audio frequencies and lower gain. 797 works quite well with class A bias, but it doesnt always benefit many modern chips, as they are mostly designed to work in class A as it is.
> 
> loving THS4150 at the mome (fully differential chip) this range of chips contains much of the same circuitry as the discrete solid state Pass Labs super symmetry (SUSY) designs, so much so that they had to buy a license from Nelson in order to use it. handy little group of chips, the VCOM pin servos the output to the voltage applied to it, easy offset adjustment. they will also directly take a single ended input with the - signal pin tied to ground and output fully balanced audio
> 
> but most importantly, it sounds excellent!! no grain, slams like a mofo and dynamics for miles


 


  What have you compared it to?
   
  Would it work in fairly standard buffered opamp layout (ie in my M-Stage) or would it require additional work / mollycoddling (like the 797's apparently often do)?
   
  (considering whether to add it to my extensive opamp trialing list)


----------



## Avro_Arrow

Be warned the THS4150 has a completely different pin out from a single op amp.


----------



## dlaloum

Quote: 





avro_arrow said:


> Be warned the THS4150 has a completely different pin out from a single op amp.


 


  As in the standard Dual Op amp pin out (such as OPA2134) - or something completely different?


----------



## Avro_Arrow

Most Dual op amps share a common pin out.
  Most Single op amps also share a common pin out which is different from dual op amps.
  Even the BUF634 has a pin out compatible with single op amps in some situations.
  THS4150 does not share the pinout of any dual or single op amp.
  You would not be able to roll this into a circuit which was not designed for it.
  
  Quote: 





dlaloum said:


> As in the standard Dual Op amp pin out (such as OPA2134) - or something completely different?


----------



## qusp

Quote: 





dlaloum said:


> What have you compared it to?
> 
> Would it work in fairly standard buffered opamp layout (ie in my M-Stage) or would it require additional work / mollycoddling (like the 797's apparently often do)?
> 
> (considering whether to add it to my extensive opamp trialing list)


 


  THS4131, PCM1632 and thats about it, I dont sit down rolling opamps so much these days, its really not the best way to gain good results IMO, but its fun for a while. this one I just knocked up a simple datasheet-o-like circuit on perf initially to test (powered with 4 x A123 lifepo4 cells) and i've just rolled it in in place of OPA1632. a couple of days ago. 
   
  the guys are right, its not going to be much good unless you at least have some way of changing the power and signal pinout of your socket and are able to add different decoupling etc its actually pretty well behaved, given some bandwidth limiting and resistance to buffer it from any capacitive loading, yes it needs a totally different set up to what you will have installed. there arent all that many fully differential chips around, this one is more flexible than some too given what I said above. basically if you can bend the circuit to supply power (it will actually work with single supply as well) to the right pin and are able to pull the output from it, it will give you balanced output fro SE input with a single supply.needs at least 16-20v to come into its own though (+/-8-10v)


----------



## Charminbaer

Quote: 





murrays said:


> I recommend Tangent's website, which has a good write-up on dealing with "cranky" op-amps http://tangentsoft.net/audio/hs-opamp.html.  If you find it difficult to understand you may need to search out some op-amp tutorials to fill in some of the basics.


 
   
  Thank you for this very informative link.
   
  So in my case i have to connect a 4.7uf Tantalum and a 0.1uf ceramic capacitor in parallel as close as posible to pin 4 and from there to ground. The same for pin 7. As described on Page 13 in the AD797 Datasheet.
  And i have to measure the resistance of R1 and R2 , then fill them into the formula provided from tangent to get the right capacitance. And this, preferably a polypropylene, is to be put between pin 2 and 6.
   
  Is that correct ?
   
  Ps: The pin-layout is for a single opamp, so whats about a Dip8 socket? what has to be modified in that case ?
        I found a schematic : http://cimarrontechnology.com/%5Cpdf%5C020302sch.pdf
        The polypropylene has to be put between pin 1/2 and another one between pin 6/7?  The tantalum&ceramic have to go from pin4 to ground and from pin8 to ground?


----------



## murrays

Quote: 





charminbaer said:


> Thank you for this very informative link.
> 
> So in my case i have to connect a 4.7uf Tantalum and a 0.1uf ceramic capacitor in parallel as close as posible to pin 4 and from there to ground. The same for pin 7. As described on Page 13 in the AD797 Datasheet.
> And i have to measure the resistance of R1 and R2 , then fill them into the formula provided from tangent to get the right capacitance. And this, preferably a polypropylene, is to be put between pin 2 and 6.
> ...


 
   
  The pinouts for the 8 pin package are on the front page of the AD797 datasheet. They are the same for DIP and SOIC.  Pins 4 and 7 are the power inputs.  There is no pin for ground - you will have to find the nearest ground (zero volts) point on the circuitboard.
  I suggest starting with the power supply decoupling which are the 2 pairs of 4.7uf Tantalum and a 0.1uf ceramic capacitors in parallel that you mentioned from the datasheet.  That may be enough.  Otherwise, the capacitor from pin 2 to pin 6 will be for bandwidth limiting in the feedback loop.
  This can be more difficult if you are using chip adapters, as the bypassing components should be as close to the chip as possible.  Some adapters have facility to mount bypassing caps on board.  I like to solder the bypass caps to the underside of the PCB beneath the op-amp socket, directly from the socket pin to the ground point.
  Some design techniques work for all op-amps in general (e.g. power supply bypassing), while others are specific requirements of individual chip designs.  Pin 8 on the AD797 is one such individual feature which is outlined in the datasheet. The LT1028 has pin 5 for tuning.


----------



## qusp

sometimes you will find that the pins that are labelled NC or 'not connected' are tied to ground


----------



## Charminbaer

Quote: 





murrays said:


> The pinouts for the 8 pin package are on the front page of the AD797 datasheet. They are the same for DIP and SOIC.  Pins 4 and 7 are the power inputs.  There is no pin for ground - you will have to find the nearest ground (zero volts) point on the circuitboard.
> I suggest starting with the power supply decoupling which are the 2 pairs of 4.7uf Tantalum and a 0.1uf ceramic capacitors in parallel that you mentioned from the datasheet.  That may be enough.  Otherwise, the capacitor from pin 2 to pin 6 will be for bandwidth limiting in the feedback loop.
> This can be more difficult if you are using chip adapters, as the bypassing components should be as close to the chip as possible.  Some adapters have facility to mount bypassing caps on board.  I like to solder the bypass caps to the underside of the PCB beneath the op-amp socket, directly from the socket pin to the ground point.
> Some design techniques work for all op-amps in general (e.g. power supply bypassing), while others are specific requirements of individual chip designs.  Pin 8 on the AD797 is one such individual feature which is outlined in the datasheet. The LT1028 has pin 5 for tuning.


 

 No i didnt mean that. What i wanted to know is if i can solder the 2 bypass caps from pin 8 and pin 4 of the dual socket to ground. I dont want to kill the opamp during soldering, therefore i would prefer soldering on a replaceable socket. Will i need other caps in that case , since im bypassing 2 opamps instead of just one directly? I would not like to solder to the board directly if possible.
  The Datasheet says the benefits of Pin8(single Soic) are mainly for high gain or and/or high frequencies : "Use of this feature improves distortion performance when the closed-loop gain is more than 10 or when frequencies of interest are greater than 30 kHz."  
  Would it bring me any benefit if i would like to use my amp with lower or equal gain?
   
  Quote:


			
				qusp said:
			
		

> sometimes you will find that the pins that are labelled NC or 'not connected' are tied to ground


 
   
  If i look at the layout of the  "2xSoic to 1xDip Adapter" i can see no grounding. Isn´t there another way to get to ground without soldering directly to the board?
   
   
  So many Questions. 
	

	
	
		
		

		
			




  Thanks to you guys for helping me ,I hope i m not using up too much of your time.


----------



## dlaloum

Maybe you can use a multimeter on continuity test mode, try each pin compared to ground (pretty much anywhere on the board) if one of the pins comes up positive you are in business.... if not, you can always run a ground strap.
   
  The Audio-Gd discrete opamps often do that - they plug into the socket but also have a wire to connect to ground, which is a fairly simple thing, and may even be doable without soldering depending on the amp. (well without soldering anywhere except the socket that is!)


----------



## qusp

the adapter has no ground pin, in fact it has no pins labelled at all of any type, pinouts are different for everything that uses it. no, what I mean is, most opamps, if you look at the datasheet and the pin assignments for the opamp, it will have a couple of pins that are not used for anything; these are usually labelled NC, for No Connection, these pins, whatever they may be for the chip in question are sometimes tied to ground to avoid them acting as an arial and picking up noise. it will depend on the designers choices. just saying that if you can check those pins with a meter you may find that they are rather conveniently placed grounding points...or you may not....


----------



## qusp

when I make amps that will be rolled, I always install a sip socket pin so that the decoupling can be plugged in and disconnected without soldering. I suggest you do the same if there are no pins on the dip tied to ground and no, not 'pretty much anywhere on the board' as close as possible to the socket, installing an aerial to pick up noise and shunt it to ground is not such a good thing


----------



## Charminbaer

Quote: 





			
				dlaloum said:
			
		

> Maybe you can use a multimeter on continuity test mode, try each pin compared to ground (pretty much anywhere on the board) if one of the pins comes up positive you are in business.... if not, you can always run a ground strap.
> 
> The Audio-Gd discrete opamps often do that - they plug into the socket but also have a wire to connect to ground, which is a fairly simple thing, and may even be doable without soldering depending on the amp. (well without soldering anywhere except the socket that is!)


 

 okay i will try this as soon as i can get myself to stop listening , soundquality of the AD797BR is amazing, even with noise from the high gain 
	

	
	
		
		

		
		
	


	



   
  Quote: 





			
				qusp said:
			
		

> the adapter has no ground pin, in fact it has no pins labelled at all of any type, pinouts are different for everything that uses it. no, what I mean is, most opamps, if you look at the datasheet and the pin assignments for the opamp, it will have a couple of pins that are not used for anything; these are usually labelled NC, for No Connection, these pins, whatever they may be for the chip in question are sometimes tied to ground to avoid them acting as an arial and picking up noise. it will depend on the designers choices. just saying that if you can check those pins with a meter you may find that they are rather conveniently placed grounding points...or you may not....


 
   
  I very well understood you. But even though there are such pins on the AD797, how can they be grounded if they are not even connected via the "2xsoic to 1xDip adapter"?

  
   
  Quote: 





qusp said:


> when I make amps that will be rolled, I always install a sip socket pin so that the decoupling can be plugged in and disconnected without soldering. I suggest you do the same if there are no pins on the dip tied to ground and no, not 'pretty much anywhere on the board' as close as possible to the socket, installing an aerial to pick up noise and shunt it to ground is not such a good thing


 


 Damn, so i have to solder to the board in the end.
  That socket is a very good idea. I will try that.
   
  EDIT:
   
  I found out, that a screw in direct proximity to the opamp socket is grounded. So i don´t need to solder, i can use the screw to secure the wire.


----------



## Charminbaer

hm... i did it, but i hear just a loud hum. Unplugged the socket with the caps, now everything works as before. Strange.
  Could this be because i did not directly solder it to the opamp?
   
  Edit:
   
  Just checked the temperature of the topside opamp , it´s 70°C without cover on the m-stage 
	

	
	
		
		

		
		
	


	



  Is that because of oscillation or is it normal ? Seems too hot for me.
  the HA3-2525-5Z merely reached 40°C.


----------



## murrays

Quote: 





charminbaer said:


> Just checked the temperature of the topside opamp , it´s 70°C without cover on the m-stage
> 
> 
> 
> ...


 
   
  That's definitely not good.  That one certainly failed the "finger" test.
  Most chips won't get much more than luke warm.  You should be able to hold your finger on it forever.


----------



## qusp

yep, oscillation city!! ..not good. i'm saying the 797 is not liking your circuit at all. there could be all manner of issues at hand here mate, what sort of caps did you use, was the screw really at power supply ground, or some other ground potential? its posible the opamp is using a completely different reference voltage for its 'ground'  you may have reversed the polarity on one of the caps, you may have created a ground loop, etc etc.  very difficult for us to help here, without a schematic, or pictures etc nigh impossible.


----------



## Charminbaer

Quote: 





murrays said:


> That's definitely not good.  That one certainly failed the "finger" test.
> Most chips won't get much more than luke warm.  You should be able to hold your finger on it forever.


 
   
  Yes that for sure, i am happy i didn´t try that in the first place  
	

	
	
		
		

		
		
	


	






  
  Quote: 





			
				qusp said:
			
		

> yep, oscillation city!! ..not good. i'm saying the 797 is not liking your circuit at all. there could be all manner of issues at hand here mate, what sort of caps did you use, was the screw really at power supply ground, or some other ground potential? its posible the opamp is using a completely different reference voltage for its 'ground'  you may have reversed the polarity on one of the caps, you may have created a ground loop, etc etc.  very difficult for us to help here, without a schematic, or pictures etc nigh impossible.


 
   
  I used 4.7uf tantalum and 0.1uf ceramic, don´t know which brand.
  I measured the screw against the ground pin of the power jack.
  As for the polarity, i used the "+ side of the tantalum" on V+ and "- side of the tantalum" on ground, the opposite for V- ( v- >- tant + > gnd)
  Ceramics had no marking on them and as far as i know it does not matter, or am i wrong ?
  I tried to get a schematic but i did not find one. Wrote some emails to coolfungadget and the Matrix online store. Got no reply so far.
  I will try to do some pictures tomorrow.
   
   
  I talked to a electrical engineer i know and he wants to measure the opamp with an oscilloscope to exactly know whats wrong. He advised me to use a choke on the feedback loop.
  Is a choke ok to use , since tangent advised to use polypropylene caps ?
  What do you guys think of that?


----------



## qusp

yes, but what I mean is the opamps power supply ground may be sitting at a different level to actual ground, ie there may be a rail splitter or other virtual ground being used for signal ground.you are correct that its pretty unlikely the ceramics are polar. I personally wouldnt use a choke in the feedback loop, they are too nonlinear I would stick to polypropelene or NPO ceramics. there is no reason why these techniques shouldnt work, there is something else up with your power supply or circuit; the 797 needs 30pf or so in the feedback loop for bandwidth limiting as its much wider bandwidth than we need for audio and can oscillate without it. have you done this? make sure you bring the datasheet with you if you go over to see your friend, hard to know what else to say without more info or pics.
   
  good luck


----------



## murrays

Quote: 





charminbaer said:


> I used 4.7uf tantalum and 0.1uf ceramic, don´t know which brand.
> I measured the screw against the ground pin of the power jack.
> As for the polarity, i used the "+ side of the tantalum" on V+ and "- side of the tantalum" on ground, the opposite for V- ( v- >- tant + > gnd)
> Ceramics had no marking on them and as far as i know it does not matter, or am i wrong ?
> ...


 
  The ground point for bypass caps must be the closest point on the circuitboard ground plane. It must be a very short path to the main ground point as seen by the amplifier circuit.  If you are using a screw by the power jack it may be too far and not the best ground.
   
  Ceramic capacitors do not have voltage polarisation.  Tantalums DO, and can be very sensitive to reversals (BANG!!).
   
  Taking measurements with an oscilloscope will help.  It's the best way to see oscillations, as they generally won't be audible.
   
  As for components to help stabilise the circuit - as others have said, this is dependent on the individual circuit design.  Your electrical engineer may be able to help you, otherwise you may be in for some lengthy experimentation.  This is a problem beyond normal audio range and into HF/VHF range, so it needs to be looked at from that perspective too.  The circuit design and layout may be fine for the original chip but may just have too many issues to allow the new chip to run in a stable manner.


----------



## teamanon

Hi there fellow audiophiles. I just joined head-fi so I could post in this thread and ask for assistance. I have the ASUS Xonar Essence STX and In it i have (2x) OPA2111KP's and I love them. See the problem is that I still have the stock OPA in the other slot (pic related) and I was wondering what do you recommend to go with my (2x) OPA2111KP's?
   
  I am looking for one that has amazing clarity in the mid-high range. Any suggestions?


----------



## murrays

Quote: 





teamanon said:


> Hi there fellow audiophiles. I just joined head-fi so I could post in this thread and ask for assistance. I have the ASUS Xonar Essence STX and In it i have (2x) OPA2111KP's and I love them. See the problem is that I still have the stock OPA in the other slot (pic related) and I was wondering what do you recommend to go with my (2x) OPA2111KP's?
> 
> I am looking for one that has amazing clarity in the mid-high range. Any suggestions?


 
  Hi, Welcome to Head-Fi.  
	

	
	
		
		

		
		
	


	



  While you wait for those in the know, it might pay to do a search on that particular card as I seem to recall it being the topic of many previous discussions. Even just narrow it down to this thread, you should find some postings.


----------



## teamanon

Thanks for your reply.  I was hoping someone could just recommend a good one to go with my (2x) OPA2111KP's.  I read some of this thread, but it is 200 pages long and I don't have the time to read all of it.  I am only looking for one (x1) OP AMP to go in the single slot in my ASUS Xonar Essence STX soundcard(pic related).  Something that makes the mid-high range of the audio clear and crisp preferably.


----------



## Charminbaer

Unfortunately we had not enough time to measure every frequency for oscillation, but we found the opamp to oscillate at around 4Mhz. My friend said it could be that it oscillates at a higher frequency but it shows up at 4Mhz. He put some 22pf ceramics in the feedback and oscillations at 4Mhz disappeared.
  At home i listened for a couple of hours and it sounds much better at 0db gain. Nothing like before.
  But the opamp temperature is still at 63°C. An improvement of 7°C. But this is still too high, isn´t it ? Could it be that it still oscillates?
   
   
  Quote:


qusp said:


> yes, but what I mean is the opamps power supply ground may be sitting at a different level to actual ground, ie there may be a rail splitter or other virtual ground being used for signal ground.you are correct that its pretty unlikely the ceramics are polar. I personally wouldnt use a choke in the feedback loop, they are too nonlinear I would stick to polypropelene or NPO ceramics. there is no reason why these techniques shouldnt work, there is something else up with your power supply or circuit; the 797 needs 30pf or so in the feedback loop for bandwidth limiting as its much wider bandwidth than we need for audio and can oscillate without it. have you done this? make sure you bring the datasheet with you if you go over to see your friend, hard to know what else to say without more info or pics.
> 
> good luck


 

 Yes, you´re right it was a different ground. My friend showed me the right source to ground. They are pins as you would have done it. I will  try to bypass power supply, this time to the right ground 
	

	
	
		
		

		
		
	


	




. I will use smd caps my friend gave me, he said they do a better job than ceramics in terms of power supply bypassing.
  What do you think about "Glimmer" Caps for the feedback loop?

  
  Quote: 





murrays said:


> The ground point for bypass caps must be the closest point on the circuitboard ground plane. It must be a very short path to the main ground point as seen by the amplifier circuit.  If you are using a screw by the power jack it may be too far and not the best ground.
> 
> Ceramic capacitors do not have voltage polarisation.  Tantalums DO, and can be very sensitive to reversals (BANG!!).
> 
> ...


 
   
  The ground pins are about 1,5cm away from the opamp. the screw was about 6cm away, and apparently the wrong ground.
  It would be a shame if i couldn´t use the AD797, because it sounds so much better than every other opamp i´ve heard before. What do you think about noise cancellation feature on pin8 ? Would it bring any benefits or disadvantages ?


----------



## murrays

Quote: 





charminbaer said:


> Unfortunately we had not enough time to measure every frequency for oscillation, but we found the opamp to oscillate at around 4Mhz. My friend said it could be that it oscillates at a higher frequency but it shows up at 4Mhz. He put some 22pf ceramics in the feedback and oscillations at 4Mhz disappeared.
> At home i listened for a couple of hours and it sounds much better at 0db gain. Nothing like before.
> But the opamp temperature is still at 63°C. An improvement of 7°C. But this is still too high, isn´t it ? Could it be that it still oscillates?


 
    
  I forgot to mention before that you should check for DC offset.  With no signal input the output pin(s) of the opamp should be at close to zero voltage.  Usually you can expect up to +/- 20 mV or so.  If there is DC on the output it may cause unwanted current to flow which will raise the temperature (similar to the "class A" mod), but may also be bad for the headphones if there is no DC blocking capacitor at the output.
  Can you friend help by measuring the power supply current?  Most opamps have short-circuit current limiting, so oscillations is one main way to get them really hot.
   
  Quote:


charminbaer said:


> Yes, you´re right it was a different ground. My friend showed me the right source to ground. They are pins as you would have done it. I will  try to bypass power supply, this time to the right ground
> 
> 
> 
> ...


 
    
  It sounds like your friend is giving some good help. SMD caps are good because they have no wire leads - you can't get much shorter than that.  The small size and lack of leads is good for the high-frequency performance that is required.


----------



## qusp

yes, but i'm finding it difficult to think of an SMD cap that is better than NPO ceramics for bypassing the power supply pins 
	

	
	
		
		

		
		
	


	




 it could be an SMD film, but even those although I subjectively prefer them, are inferior to quality ceramics for bypassing and relatively rare in most engineering type circles. do you know what sort of cap they are? ceramic caps have low impedance at high frequency, which is what you want. suppose it could be some sort of polymer cap, but they are better for local reservoir caps and have higher impedance at high frequency. I would actually use both personally, I would put an SMD special polymer/tantalum polymer cap (10-20uf) in parallel to an SMD pps film or NPO/c0g ceramic (10-100nf)
   
  s9ounds like you are on the right track though. as far as caps in the feedback loop, really as long as its low impedance at high frequencies like ceramic or film you'll be fine, caps in the feedback loop really do not contribute much character to the sound IMO, so as long as they are able to do the job they'll be fine


----------



## Charminbaer

Quote:  





> I forgot to mention before that you should check for DC offset.  With no signal input the output pin(s) of the opamp should be at close to zero voltage.  Usually you can expect up to +/- 20 mV or so.  If there is DC on the output it may cause unwanted current to flow which will raise the temperature (similar to the "class A" mod), but may also be bad for the headphones if there is no DC blocking capacitor at the output.
> Can you friend help by measuring the power supply current?  Most opamps have short-circuit current limiting, so oscillations is one main way to get them really hot.


 
   
  Ah okay, i will ask him if he could check that.
   
   
   
  Quote: 





> murrays said:
> 
> 
> 
> ...


 
   
  Yes he is helping me very much. The best thing is that i learn new interesting things every time i visit him 
	

	
	
		
		

		
		
	


	



  Those smd caps are also very practical to mount on the opamp adapter, since they are little squares they fit perfectly in the left over space. I will use glue to secure them. The wire between opamp pin and cap will be approximately 1mm.

  
   Quote: 





			
				qusp said:
			
		

> yes, but i'm finding it difficult to think of an SMD cap that is better than NPO ceramics for bypassing the power supply pins
> 
> 
> 
> ...


 

   
  No, what i meant is that they are better suited than standard built caps. The SMD caps are also NPO ceramic ( http://www.conrad.de/ce/ProductDetail.html?hk=WW2&utm_source=zanox&utm_medium=deeplink&utm_content=dl_article&utm_campaign=tracking&insert=U1&WT.mc_id=epro&productcode=460354&zanpid=1433036390790386688 )
  Glimmer is the german name for SilverMica. What do you think about those? I read their capacity does not fluctuate that much with different temperatures.


----------



## qusp

honestly, for this job, use whatever you have thats the right value and the right and convenient size, like I said, not really gonna change the flavor as the thing about feedback is it corrects errors, errors are what gives flavor to some degree, so yeah if the mica fits just use it and listen, then try not to worry about it. if I were to buy a cap for this purpose and didnt actually have a trace to solder it into, I would buy a leaded goldenmax NP0 ceramic, or a evox/rifa film and polypropelene foil (hard to get, but excellent caps)


----------



## Charminbaer

Quote: 





qusp said:


> honestly, for this job, use whatever you have thats the right value and the right and convenient size, like I said, not really gonna change the flavor as the thing about feedback is it corrects errors, errors are what gives flavor to some degree, so yeah if the mica fits just use it and listen, then try not to worry about it. if I were to buy a cap for this purpose and didnt actually have a trace to solder it into, I would buy a leaded goldenmax NP0 ceramic, or a evox/rifa film and polypropelene foil (hard to get, but excellent caps)


 

 I have ordered some silver mica caps, i couldn´t find any evox or goldenmax. I can get silver micas cheap and with a tolerance of 1%.
  I also did the power supply bypassing. Improved the sound noticeable.
  Now everything sounds more detailed and the soundstage is much deeper.


----------



## Elar

I am looking for some opamps to try with my Matrix M-Stage headphone amp. What I am looking to improve in the amp is to get a bigger soundstage and better separation of the instruments. After some research I came up with these choices:
   
  - LM4562NA-ND
  - LME49720NA-ND (is this any different from the above?)
  - LT1057CN8#PBF-ND
  - OPA637AP-ND (2x)
  - AD843JNZ-ND  (2x)
   
  Any recommendation for any other opamp that it's worth trying to improve the aspects I mention above (or some other opamp that is worth listening to, for example any tube-like sounding one), please do so. The two LM and the LT opamps are duals and will install easily.
   
  The OPA and AD are singles and will need adapters. I ain't able to find something like the BrownDog's Single-to-Dual opamp adapter at Digi-Key, if someone can point me at one at Digi-Key, that'd be great. I'll put two 8-pin IC socket on that adapter and mount in each of them the single opamps. Which one of these socket is best, or are they the same:
   
  - ED90032-ND
  - ED90208-ND
   
  The other thing I would like to do at some point, and now it's a good opportunity to get the components for that, is to make the opamp into class A. In the Tangentsoft's guide are described different methods to do that. For the first method with the resistors, are these resistors ok to use?
   
  - P3.9W-3BK-ND
   
  I'd like to give the JFET Cascode method a go also, but I don't have a clue what to buy, so if anyone can link me with the correct JFETs at Digi-Key, I'd be grateful (I can't find 2N5486 or 2N5484 mentioned in the guide). All the soldering required will be done by a friends of mine, but I need to buy all components required, and as post fees are too high, I am trying to order everything needed in one go (Digi-Key has free posting for orders above 65 euro). Thanks.


----------



## Mad Max

I'd recommend OPA627AP instead of 637 as 627 is unity-gain stable whereas 637 will only be stable at the 10, 18, and 20 gain settings (it needs at least 5 gain).  This, however, excludes whether or not the opamp will like the circuit or not and I would be a little surprised if it did run stable.  The M-Stage doesn't seem to be all that friendly towards high-speed opamps in general.
   
  Also try HA3-2525-5 (slightly tubey and seems to be relatively stable to boot).


----------



## K3cT

I haven't tried op-amp rolling in the M-Stage but I can vouch for the class A-biased OPA627 to be amazing sounding with the M-Stage. I really wouldn't bother with any other combinations.


----------



## Elar

Thanks. I use gain settings at 10 atm with my HD650, was using 18 for a while without any problems. The guy at Tangentsoft says that 637 sounds a little bit (like 5%) better then 627. Isn't anyone here using 637 with M-Stage? I don't know, I may go for the 627 after all just to be safe. The HA3-2525-5 is out of stock at Digi-Key and sold in minimum quantities of 1000 units.
   
  Now if someone could answer my other questions below, you'll make me a happy would-be-diyer. Thanks.
   
  Quote: 





> The OPA and AD are singles and will need adapters. I ain't able to find something like the BrownDog's Single-to-Dual opamp adapter at Digi-Key, if someone can point me at one at Digi-Key, that'd be great. I'll put two 8-pin IC socket on that adapter and mount in each of them the single opamps. Which one of these socket is best, or are they the same:
> - ED90032-ND
> - ED90208-ND
> 
> ...


----------



## Mad Max

... nevermind


----------



## Charminbaer

Quote: 





elar said:


> Thanks. I use gain settings at 10 atm with my HD650, was using 18 for a while without any problems. The guy at Tangentsoft says that 637 sounds a little bit (like 5%) better then 627. Isn't anyone here using 637 with M-Stage? I don't know, I may go for the 627 after all just to be safe. The HA3-2525-5 is out of stock at Digi-Key and sold in minimum quantities of 1000 units.
> 
> Now if someone could answer my other questions below, you'll make me a happy would-be-diyer. Thanks.
> 
> ...


 

  
  If your opamp is stable at 0db gain, i would run it in that setting. Noise gets higher and linearity decreases as you rise gain. HA3-2525-5 and AD797BR sound better at 0db gain. Especially the Ad797 sounds amazing. Sound-stage and instrument separation is much improved, but only with the mods i did with help of murrays and qusp.
   
  The bottom link leads to a large list of opamp measurements:
   
  http://www.sg-acoustics.ch/analogue_audio/ic_opamps/pdf/opamp_distortion.pdf


----------



## spydur

I'm trying to upgrade the op-amp on my Cmoybb 2.02 to an AD825. Problem is i found 3 variations of the chip. Which one would i need and where is a good place to buy it? I would also need a place to buy the dip to soic cionverter. I can solder the adapter together. Also, anyone know where one can purchase an 18v or 24v dc power adapter in the US?


----------



## dlaloum

Quote: 





elar said:


> Thanks. I use gain settings at 10 atm with my HD650, was using 18 for a while without any problems. The guy at Tangentsoft says that 637 sounds a little bit (like 5%) better then 627. Isn't anyone here using 637 with M-Stage? I don't know, I may go for the 627 after all just to be safe. The HA3-2525-5 is out of stock at Digi-Key and sold in minimum quantities of 1000 units.


 

  
  I tried the OPA637 for a few weeks in my M-Stage - ended up going back to OPA627 - both running class A
   
  The HA3-2525 can usually be obtained from Intersil as a sample (at zero cost)
   
  I have a pair, but have not got around to testing them and comparing to the 627 (which is now my benchmark)


----------



## Elar

Quote: 





dlaloum said:


> I tried the OPA637 for a few weeks in my M-Stage - ended up going back to OPA627 - both running class A
> 
> The HA3-2525 can usually be obtained from Intersil as a sample (at zero cost)
> 
> I have a pair, but have not got around to testing them and comparing to the 627 (which is now my benchmark)


 

 What is the reason you like 627 more than 637? Is it stability, heat, sound quality?


----------



## Avro_Arrow

I feel so sad today, I accidentally let all the magic smoke out of my OPA690s.
  My IEM's were so upset that all the magic smoke came out of them too...
	

	
	
		
		

		
		
	


	



  I guess thats the last time I will let the OPA690s play with +- 12 volts!


----------



## svyr

avro_arrow said:


> I feel so sad today, I accidentally let all the magic smoke out of my OPA690s.
> My IEM's were so upset that all the magic smoke came out of them too...
> 
> 
> ...






> The internal junction breakdown voltages are relatively low for these very small geometry devices. These breakdowns are reflected in the Absolute Maximum Ratings table.
> 
> ABSOLUTE MAXIMUM RATINGS(1)
> Over operating free-air temperature range, unless otherwise noted.
> ...



http://focus.ti.com/lit/ds/symlink/opa690.pdf

So you knew it'd fry it, but still tried?


----------



## Avro_Arrow

I am very familiar with the rated voltages for the op amps I have...but it still
  doesn't stop you from forgetting to change to voltage on the power supply
  just that one time...I was rolling a group through my test amp to see how
  they sounded at different voltages.
  
  Quote: 





svyr said:


> Quote:
> 
> 
> 
> ...


----------



## svyr

avro_arrow said:


> I am very familiar with the rated voltages for the op amps I have...but it still
> doesn't stop you from forgetting to change to voltage on the power supply
> just that one time...I was rolling a group through my test amp to see how
> they sounded at different voltages.




fair enough, my condolences, hopefully opa690 isn't too expensive(I could find a datasheet, but not where to buy one ) . Otoh, you'll probably have somewhat of a reflex for checking the psu voltage some time to come =)


----------



## majkel

Mouser should have the OPA690. You can also try Farnell or RS Components.


----------



## Avro_Arrow

It's not really a problem...I have eight more...


----------



## Avro_Arrow

I must report that after I adjust the power supply to a less vigorous voltage
  that the magic smoke stayed inside where it belongs and the OPA690s
  sounded great! 
	

	
	
		
		

		
		
	


	



   
  The only bad news is the IEMs are down and out for the count...


----------



## igor0203

Which opamp you suggest for swapping instead of LME49720HA or LT1028? I wanna try something "better".  I'm using Club3D Agrippa DTS 7.1 which is just like Auzentech X-Plosion.


----------



## svyr

igor0203 said:


> Which opamp you suggest for swapping instead of *LME49720HA* or LT1028? I wanna try something "better".  I'm using Club3D Agrippa DTS 7.1 which is just like Auzentech X-Plosion.




mm, I second the question. I have a pair of LME49720HA (detailed but not harsh, maybe a bit on the warm side of mids, and a bit too expensive  ) and they're the best I tried, but I'd be interested to know if there are 'better' things out there


----------



## Mad Max

ADA4627-1B is what you want.  Only comes in soic form.
  That is as good as it gets.



  
  Quote: 





svyr said:


> (www.head-fi.org/forum/thread/432749/the-opamp-thread/3300#post_70697*11*)


----------



## Mad Max

Edit: to type under a quote, click on _Source_ and then add:
   
  <p>
  </p>
   
  at the very bottom.


----------



## SpudHarris

x2 in almost any of my amps these sound amazing.
   
  Why can't I write under the quotes anymore?
  
   
  Quote:


mad max said:


> ADA4627-1B is what you want.  Only comes in soic form.
> That is as good as it gets.


----------



## dlaloum

Quote: 





elar said:


> What is the reason you like 627 more than 637? Is it stability, heat, sound quality?


 
   
  During a few weeks listening to the 637, I found that it seemed there was more detail in the highs.... a "well lit" sound... seemed a bit more space too - but it was fatiguing to listen to, which is usually a sign of some form of distortion/grunge in the highs.
   
  Going back to the 627 -  definitely darker - but also never fatiguing - I can listen for hours to this, and just keep going.
   
  Part of the issue may also be that I am using DT880's - I believe with the more recessed highs of something like the sennheisers the 637 might be ok or perhaps even better than the 627.... not sure. I did like the fact that it wasn't as dark as the 627 - but fatiguing is a no-no, and usually a good indicator of distortion - so it might be some form of instability.
  
  One other possibility - the 627's are SOIC on a top/bottom adapter - very short traces.... the 637's are dips on a side/side adapter....
   
  I have measured more distortion and grunge/noise on DIP's in the side/side adapters - and with chips like the AD797 and OPA637 that are fairly sensitive - this may be the reason they don't score well with me.


----------



## SpudHarris

I forgot about the LT1468 until last night when looking through some old correspondance with Ryuzoh (Fi-Quest) he suggested it as a more stable replacement for the OPA637. I have these in my P3+ with stacked buffers and with Ground and Virtual Ground both bypassed. The LT1468 really suit this circuit and the P3+ sounds very open, very nuetral but lightning quick - Very, very nice..........
   
  Anyone else tried these?


----------



## Mad Max

1468 has a weird sound in my gear.  I didn't like it.


----------



## qusp

really loving the OPA827 again at the moment, that and OPA1641 are on rotation at the moment, great chips


----------



## SpudHarris

I really must have another listen to the OPA1641, I've heard good things about it........


----------



## Charminbaer

After long time reading datasheets and trying to understand opamp circuits, i came to the conclusion that the AD797 can´t be put in the m-stage without modification of the circuit.
   
  So i paralleled the source input resistors with 100ohms and also put 100ohms and 22pf in the feedback loop. 
   
  Sound-stage opened up dramatically! It sounded like the instruments are right in front and around you. I compared it against LM4562 and it has no chance against Ad797BR. In every aspect.
   
Now i only have know where the resistor for the inverting input (-IN) is. Does someone have any clue?
   
  Nevermind, i found it.
   
  Also did Class A Bias. Brought another improvement in instrument separation and sound-stage.
  I will add some RMAA measurements later on.


----------



## Charminbaer

I just measured the dc offset at the headphone output, it´s 9.9mv and -4.8mv. Can i measure the offset directly at the opamp output pins to ground? 
  I´ve read somewhere it can be reduced by using a pot between pin 1 and 5. Is that correct or do i have to pay attention to something else?


----------



## qusp

sure you can use a pot to inject some of the output signal back into the inverting input to get rid of offset, but seriously, I wouldnt worry too much about that level of offset


----------



## qusp

Quote: 





charminbaer said:


> *After long time reading datasheets and trying to understand opamp circuits, i came to the conclusion that the AD797 can´t be put in the m-stage without modification of the circuit.*


 

  
  hehe theres a saying i'm searching for here somewhere, can you help me out here? 'I told you so' is that it? hehe


----------



## Charminbaer

Quote: 





qusp said:


> sure you can use a pot to inject some of the output signal back into the inverting input to get rid of offset, but seriously, I wouldnt worry too much about that level of offset


 

  
  Ok. I just wondered what would happen if i removed the coupling cap. Therefore i wanted to know how high the offset is before going through the cap. Do you think it is a good idea to remove it if i can trim down dc offset?

  
  Quote: 





qusp said:


> Quote:
> 
> 
> 
> ...


 






  Yep, you were right. 
   
  But i´m glad i tried it. I learned many new things.
   
  And i´m very happy with the sonics of the AD797, never heard something similar. The sound-stage is HUGE


----------



## qusp

sure no cap is a good cap, if you can avoid them absolutely. actually now rereading your post I had forgotten about the null pins and was just describing how you might do it with a regular differential input opamp ie inject DC into the inverting input, but the 797 has its purpose built pins for this, so yeah go for it. youve done the distortion cancellation trick too yeah? its a tricky little opamp and the datasheet is full of good info and now you can see why you cant just drop it in and expect the best results. 
   
  indeed bass slam and soundstage are superb with this chip.


----------



## Charminbaer

Quote: 





qusp said:


> sure no cap is a good cap, if you can avoid them absolutely. actually now rereading your post I had forgotten about the null pins and was just describing how you might do it with a regular differential input opamp ie inject DC into the inverting input, but the 797 has its purpose built pins for this, so yeah go for it. youve done the distortion cancellation trick too yeah? its a tricky little opamp and the datasheet is full of good info and now you can see why you cant just drop it in and expect the best results.
> 
> indeed bass slam and soundstage are superb with this chip.


 

 okay 
	

	
	
		
		

		
		
	


	



  I measured dc offset directly from the opamp output pins and it is only 0.6mv and -0.5mv there. Why is it that much higher at the phones output? could the buffer add offset ?
   
  yes i´ve done distortion cancelling, although i had no 50pf cap. I only used a 22pf , but it definitely changed the sound for the better.
   
  I noticed that the higher i went with the class a biasing resistors the more stable it got. Best results so far are with 10k. Less heat than unbiased and more slam. Maybe it needs more load impedance? I think i will try some JFETs.
   
  I thought about exchanging the adapter, what do you think is the best for a picky ic like Ad797? I found this one:
  http://cgi.ebay.de/10pcs-Dual-SOIC-to-DIP-8-Convert-PCB-Adapter-SMD-OPA627-/230408616394?pt=LH_DefaultDomain_0&hash=item35a56c79ca
   
  Or maybe browndogs ? Mine came with rather cheap ebay adapters.


----------



## Mad Max

Those may be better.


----------



## Charminbaer

Quote: 





mad max said:


> Those may be better.


 


  which ones? the browndogs or diyinhk ?


----------



## Mad Max

diyinhk


----------



## Charminbaer

Okay i bought them. Hope it does not take too long.


----------



## Charminbaer

Tried biasing again, this time with 15K. Another improvement. From what i have measured the m-stage uses +/- 14.15V. If i´ve not made an error bias must be at 0.943mA now.
   
  Edit:
   
  I found a schematic of the m-stage or some other BCL Clone:
  http://i774.photobucket.com/albums/yy29/davidlouis1983/_.jpg


----------



## T.B.N.

I have a quick question about the OPA2227 that I need for an Apheared 47 amp that I'm building. It is meant to drive low impedance cans like Grados. Does this alter the requirements for the 4 opamps in the schematic? Why does it require two dual channel opamps on the left and right sides of the schematic? http://benfeist.com/a47/
    

   
   
  EDIT: Nevermind, I guess the two opamps in the schematic are simply the 8 pins of one opamp.


----------



## mencargo

Hi everyone!
   
  I want to make a DIY project with a Creative Sound Blaster Live 24bits, SB04100
   
  I found this thread, great info, but I would like recommendations for opamps and capacitors, and I saw this opamp thread, but since it started more than a year ago and has 222 pages, I got desperate after some reading.
   
  My current favorites based only on reviews and recommendations are:
   
   
  LM4562
  AD8066
  OPA2211A
  ADA4627-1
   
  But I don't even know if I can place all of them at my card, open for suggestions.
  I think I enjoy, in decreasing order, soundstage, detail, mids, bass, treble.


----------



## Charminbaer

Quote: 





mencargo said:


> Hi everyone!
> 
> I want to make a DIY project with a Creative Sound Blaster Live 24bits, SB04100
> 
> ...


 

 Hi,
   
  good electrolytic capacitors are for example Nichicon KZ , Nichicon FG , Elna Silmic RFS II. Maybe this is the right tread for you:  http://www.head-fi.org/forum/thread/284863/orgy-of-capacitors-the-cap-thread#post_3646129
   
  LM4562 has very strong treble, too much for my taste. Sometimes grainy. Soundstage is okay.
  I have read somewhere in this thread that ADA4627-1 should have a good soundstage. But don´t rely on that ,i have never heard it myself.
  Some people think OPA128SM is one of the best opamps, even superior to OPA637SM. But the cheapest i have seen is 80$ for a pair on ebay.
  AD797BR has a superb soundstage and is very neutral over all audio frequencies, but it´s a pain in the ass to get it stable.


----------



## leeperry

charminbaer said:


> LM4562 has very strong treble, too much for my taste. Sometimes grainy. Soundstage is okay.


 

 I'm afraid things are more complicated than they seem. LM4562MA in the PCM1793 Spitfire DAC is not bright/shrill and has very solid bass. I hate the SS, though. it seems to dig deep to impress, but it's too colored and brings to the front stuff that should stay where it is. Very impressive for a few hours, then dead boring IME.


----------



## Charminbaer

Quote: 





leeperry said:


> charminbaer said:
> 
> 
> > LM4562 has very strong treble, too much for my taste. Sometimes grainy. Soundstage is okay.
> ...


 

 hm okay, i´ve only tried it in the m-stage and on my Auzentech Prelude. On both it sounded a little bit harsh.
  I can imagine it could sound different on other equipment.
  I agree that SS is strange at stock, but as soon as I did some powersupply bypassing with 0.1uf ceramics and 4uf mkps it got much more realistic. Bass did also improve a little bit, but on my setup it is still not very deep.


----------



## SpudHarris

Hello Guys,
   
  haven't posted here in a while but have been checking back periodically to see if there is a new FOTM 
   
  Well if you guys haven't tried it you really must get the ADA4637-1. I believe only the ARZ version is available at present which I got a few days back. The ADA4627-1 has been a favorite of many for a while (me included) but I like the 4637 more.
   
  I'm not 100% sure how to explain how they differ. Ryuzoh of Fi-Quest fame says a more detailed version of the 4627 but I think the differences are more than this. Yes there is maybe a tad more detail but resolution is far better and vocals are just beautifully rendered, probably one of the best chips I have heard in terms of vocals...... Obviously circuits will play a part in results and I personally found my P3+ yealded better results than my Fi-Q.
   
  Let us know what you guys think, its been a while on this thread since we had new chips to try.


----------



## K3cT

4637 is just a decompensated 4627 right?


----------



## murrays

Hmm, from the specs it looks like the ADA4627 is meant to be a direct competitor for the OPA827. What do you think?
Look at the graph for THD vs output level, on p8 of the datasheet. It goes through the roof above about 0.8 V Rms. That must be where the class A bias ends and it starts getting crossover distortion.


----------



## Mad Max

4637-1A's warm haze is very pleasant.  I still like 4627-1B better.
  Either is an awesome chip.


----------



## LuciferX

Hi! Quick question:



 I orderer LT1364CN DIP8 samples, how i should combine it with OPA2107 in my Claro Halo?

 U8+U10 = OPA2107AP - U9+U11=LT1364CN



 or



 U8+U10 = LT1364CN - U9+U11=OPA2107AP



 U8+U10 are LPF and U9+U11 final buffer?



 The circuit should be: DAC >> U8+U10 >>> U9+U11 >>> RCA OUT / HP OUT?





 Thanks!


----------



## Theodore

Hi.
  I saw the following original Asus item.
  [size=x-small]*ASUS Xonar Op AMP Upgrade Kit for Essence ST/STX*[/size] .
  Does some guy know something about it?


----------



## Charminbaer

It´s two LME49720NA. They are almost similar to LM4562NA.
   
  http://www.newegg.com/Product/Product.aspx?Item=N82E16800998157


----------



## LuciferX

Hi, I need a quick comparison between OPA2107AP and LT1364CN (Both DIP8) ... I have a Claro Halo soundcard (C-Media Oxygen HD CMI8788 Audio Processor - 24-bit/192kHz AK4396VF (120dB-part spec.) DAC), with 4 OPA2107 right now .... I want to combine OPA2107 with LT1364, but I dont know wich of them works better like LPF or Final Buffer ... Can somebody help me?


----------



## Avro_Arrow

OPA2107 and LT1364 are apples and oranges, they are not directly comparable.
   
  OPA2107 is a low noise JFET op amp.
  LT1364 is a high bandwidth, high slew rate Bi-Polar op amp.
   
  With OPA2107, you will not receive the full benefit from LT1364.
   
  If the circuit will handle the Bi-Polar input op amp, I would go
  with all LT1364. I use one in my PCM1793 based DAC.
   
  A better (safer) part might be OPA1642 but you will have to solder it
  to an adapter for DIP8


----------



## LuciferX

So, I cant mix them? I only have 2 LT1364 ... My others OPAMP are LM4562NA, LME49720NA and LME49860NA ... What do you think about using them with LT1364 in combination?
   
  The circuit in my soundcard is: DAC >> U8+U10 (2 dual opamps) >>> U9+U11 (2 dual opamps) >>> RCA OUT / HP OUT


----------



## Avro_Arrow

The three LMs you mention seem pretty close in their specs.
  One of them would be a better choice than the OPA2107 in my opinion.
   
  I would try the LM in the LPF and the LT1364 in the buffer.
   
  Make sure to test for DC offset. The LT1364 draws about
  100 times as much bias current as a JFET op amp.


----------



## Daemos

I'm looking at some Opamps are there anything that is better than the OPA128? I know they are expensive, but from what I've read they are supposed to be one of the best.


----------



## Avro_Arrow

Better for what?
  
  Quote: 





daemos said:


> I'm looking at some Opamps are there anything that is better than the OPA128? I know they are expensive, but from what I've read they are supposed to be one of the best.


----------



## riktw

Some stuff i learned today:
   
  S THS3001 is a mean mean evil opamp, oscillates like a madman unless your PCB is really well designed.
  But when you got it to stop oscillating it sounds really nice and clear 
  Well, at school the best thing i had to compare it against was a NE5532 
  Designed and ordered a small PCB to test them with, hope they sound nice after listening a while to.
   
  http://focus.ti.com/docs/prod/folders/print/ths3001.html


----------



## Mad Max

THS4081 is really nice, but needs very clean power.


----------



## Armaegis

Can someone recommend some opamps to use for taking in a line level signal, then outputting the sums or differences of those signals into another amp? It boils down to what I'm trying to accomplish in this thread: http://www.head-fi.org/forum/thread/530374/building-an-active-balanced-ground
   
  I'm planning on building the circuit into either a 3 channel b22 or a 3 channel a20 (maybe both) and would like to simply tap power off the s22 without having to rig someting up for lower voltages.
   
  Preference for single channel opamps (but I'm open to suggestions), and I would like to try to keep costs down. I need a minimum of three opamps for the circuit, possibly five if I'm using input buffers (though the buffers would not necessarily have to be the same as the operational ones, and I don't mind using dual channel here either). I would be happier buying several sets of midrange opamps and being able to experiment rather than spend a ton of money on just a single high end set. I will also being going no higher than x2 or x3 for gain, so they will need to be stable in that range.
   
  That's about all the info I can think of off-hand.
   
  edit: and prefererably in DIP-8 so I can change them out easily with sockets
   
  Thanks.


----------



## Avro_Arrow

OPA1641 sounds decent and is pretty easy to use.


----------



## Armaegis

Quote: 





avro_arrow said:


> OPA1641 sounds decent and is pretty easy to use.


 

 Is there a DIP8 version?


----------



## Avro_Arrow

No, you have to use a Brown Dog to get DIP8
   
OPA132 would give you a native DIP8 chip with reasonable quality
  and low price. Not as good as the OPA1641 though...
   
  If you can use a BiPolar op amp in your design, LT1363 is quite good
  and available in DIP8. You have to take care to design the input properly
  to avoid DC offset but otherwise it is a pretty forgiving chip.
   
  Quote: 





armaegis said:


> Is there a DIP8 version?


----------



## Armaegis

Thanks.
   
  Hmm, I don't think I've got a steady enough hand to solder anything onto a browndog (though I guess it doesn't hurt to try... it only costs money right? 
	

	
	
		
		

		
			





)
   
  Unfortunately, the OPA132 is not in stock at Digikey.
   
  Here are a few I've been looking at (mostly just gleaned from reading or looking at AMB)
  AD797
  OP27GP (biased to class A?)
  OPA228PA or 228P
  OPA134
  OPA227
  more expensive ones...
  OPA211
  LT1028
  OPA627
   
  I've got a few others scrawled on some pieces of paper somewhere, but I'll dig those up later.
   
  Are some opamps better at driving high impedance loads (such as an amp input) vs driving relatively low headphone loads?


----------



## Mad Max

Quote: 





armaegis said:


> ...
> Are some opamps better at driving high impedance loads (such as an amp input) vs driving relatively low headphone loads?


 

 That's what BUF634 is for.


----------



## Avro_Arrow

Or it's little brother, the OPA633 buffer....
  
  Quote: 





mad max said:


> That's what BUF634 is for.


----------



## Mad Max

ADA4610
   
  I can't wait to audition this one versus 4627.  =o


----------



## Theodore

I have the Asus Essence ST card,together with its daughter card H6.Have you any idea about the opamps of this H6 card and the possibility of changing them to something else?


----------



## SpudHarris

Quote: 





mad max said:


> ADA4610
> 
> I can't wait to audition this one versus 4627.  =o


 

 Yeah, looks interesting.
   
  Is the 4627 your favourite? I like that chip also but am rolling OPA602BP,[font= 'ms pgothic'] OPA209 and OPA121 at present in my Ibasso P4. Have you tried any of those?[/font]


----------



## Mad Max

I am awaiting a pair of 209 just out of curiosity.
   
  OPA121?  Its datasheet dates back to the eighties, is it any good?  
	

	
	
		
		

		
		
	


	



   
  I don't have OPA602 on the way, maybe next time.
   
  Yup, 4627-1B is still my favorite for being uber precise and a little lively.  Its soundstage is my favorite as well.
  Like my headphones don't already have unrealistic, ultra-sharp imaging.


----------



## Mad Max

So OPA209 is here, but I am out of spare adapters.
   
  Also, I hadn't tried out OPA827 out in my portable amp for some reason, and now that I have:  
	

	
	
		
		

		
		
	


	




  
	

	
	
		
		

		
		
	


	




  
	

	
	
		
		

		
		
	


	




  
	

	
	
		
		

		
		
	


	




  
	

	
	
		
		

		
		
	


	



  It shines very differently than when in my desktop gear.  I love it a lot more now.




   
  It brings out the best in the Minibox-E+, even more than 4627-1B could!


----------



## SpudHarris

My current favourite in my udated Fi-Q is the OPA602BP. I couln't stop listening last night, it's much more than a portable amp and capable of driving my W6 customs through to my BT880's and T1's with ease and finesse......


----------



## i_djoel2000

i'm building a diy portable amp with ground channel. now i need some advice for a good opamp with unity gain stable to be placed in ground channel. any thoughts?
   
  i will be using 9v battery hence minimum supply voltage should be 4V or less. oh, wide bandwidth feature would be good as well (>100mHz)


----------



## Avro_Arrow

Most of the time, people use the same op amp as in the signal channels.
  
  Quote: 





i_djoel2000 said:


> i'm building a diy portable amp with ground channel. now i need some advice for a good opamp with unity gain stable to be placed in ground channel. any thoughts?
> 
> i will be using 9v battery hence minimum supply voltage should be 4V or less. oh, wide bandwidth feature would be good as well (>100mHz)


----------



## olor1n

I've just received the ADA4627-1brz from a fellow Head-Fier to slot into my Audio-GD Fun's dac output stage. I'm only familiar with how the Earth and Moon hdams are installed in this slot (with ground wire side of the hdam facing the front panel). Can any one tell me what way I install the ADA4627-1brz?


----------



## Yoga Flame

Quote: 





olor1n said:


> I've just received the ADA4627-1brz from a fellow Head-Fier to slot into my Audio-GD Fun's dac output stage. I'm only familiar with how the Earth and Moon hdams are installed in this slot (with ground wire side of the hdam facing the front panel). Can any one tell me what way I install the ADA4627-1brz?


 

 Depends on the adapter that the chip is mounted on. Usually pin 1 on the adapter will have a special marking. Match this with the socket in your amp. Maybe post a pic of your opamp + adapter here.
   
  On the opamp socket, there should be a semi-circular hole on one side. This should tell you where pin 1 will go. In the picture below, the hole is on the left, so pin 1 is at the bottom left corner.


----------



## olor1n

Thanks for the reply. Unfortunately, I can't take a photo of the chip I have but it's identical to this one (other than the yellow cap on top) -
   

   
  I can't see anything to identify pin 1, but mine has the same 26fun(c) and DIYinHK marking. If looking at the image above and the chip on the right, there looks to be a white mark on the pin in the top left corner (opposite the K in DIYinHK). I might try aligning that with the notch on the socket.
   
  If it's not right, what damage can I do?


----------



## Yoga Flame

Putting in the opamp the wrong way could fry it.
   
  I've used adapters from the same seller before too. It's a dual adapter right? With one chip on top and one below? Mine is the same as what you have in the picture. It has a white dot marking pin 1. Also the soldered area around that pin is square, instead of round like the others.


----------



## olor1n

Yeah the white dot marking was very small so I was worried if it was actually the pin 1 indicator. Took a gamble and had a quick listen through crappy headphones. It seems fine. Thanks for your help Yoga.


----------



## olor1n

Early impressions of the ada4627-1brz in my setup are very positive. There's amazing detail, effortless clarity in dynamic passages, drums have impact and snap, and bass is very well defined in the balanced presentation. This may have just replaced Moon as my preferred opamp in the Fun for the HD650.


----------



## taisho

Quote: 





luciferx said:


> So, I cant mix them? I only have 2 LT1364 ... My others OPAMP are LM4562NA, LME49720NA and LME49860NA ... What do you think about using them with LT1364 in combination?
> 
> The circuit in my soundcard is: DAC >> U8+U10 (2 dual opamps) >>> U9+U11 (2 dual opamps) >>> RCA OUT / HP OUT


 


  I currently have 2 LM4562 op-amps in U8 + U10 and 2 OPA627 op-amps connected via adapter in U9 and an OPA627 superchip in U10.


----------



## Armaegis

Quote: 





olor1n said:


> Thanks for the reply. Unfortunately, I can't take a photo of the chip I have but it's identical to this one (other than the yellow cap on top) -
> 
> 
> 
> ...


 


  What are those caps for?


----------



## SpudHarris

I bought some very expensive adapters with spaces for smd caps etc but I'm lost just looking at them haha


----------



## fzman

you're not lost - you're probably behind the camera when the picture was taken, no?


----------



## Avro_Arrow

They are bypass caps. They are soldered to pins 4 and 8.
  
  Quote: 





armaegis said:


> What are those caps for?


----------



## SpudHarris

Quote: 





fzman said:


> you're not lost - you're probably behind the camera when the picture was taken, no?


 

 Haha, yes I was behind the camera - But still lost I'm afraid!


----------



## SpudHarris

Quote: 





avro_arrow said:


> They are bypass caps. They are soldered to pins 4 and 8.


 


 Is it as simple as that? what about values? Some input might just help me get some use out of those blummin' adapters I spent $100 on....


----------



## Avro_Arrow

Unless I miss my guess, your adapters have a spot for external V+, V- and Gnd connections.
  You Gnd connection gives you more bypassing options than a regular adapter. For values,
  220pF through 1uf should be the range to try. Which value works best will be up to the
  circuit and the Op Amp. The size looks the same as the SMD caps in the package in
  the background.


----------



## Armaegis

Quote: 





avro_arrow said:


> They are bypass caps. They are soldered to pins 4 and 8.


 

 The cap is attached directly to the +/- power rails? I thought you needed a pair of them, with each side going to ground.


----------



## Avro_Arrow

Both bypassing methods can by used. Some chips respond better to rail to rail bypassing
  and some better to rail to ground. Circuit design also factors into which method is better
  as well.
   
  Quote: 





armaegis said:


> The cap is attached directly to the +/- power rails? I thought you needed a pair of them, with each side going to ground.


----------



## Mad Max

Quote: 





spudharris said:


> I bought some very expensive adapters with spaces for smd caps etc but I'm lost just looking at them haha


 

 I would like love me some of those.  Where they at?  
	

	
	
		
		

		
			




   
   
  Also, ISL28110 is real nice.  Need to spend some time with it and compare to HA-2525 and 28127/55001.
  After that comes OPA209.  I gave it a go for a couple of minutes right before trying out 28110, but I'm already guessing a comparison of 209 vs. 827 and 4081 will be pretty unfair.  Who knows, I'll get around it later.


----------



## SpudHarris

^ A little while back when I was actively rolling I tagged onto an order that ''Qusp'' was placing. To be truthfull I thought they would be a little less complex 
   
  I have singles and duals + loads of smd and film caps to go with. Make me an offer!


----------



## Mad Max

I wanted the link so I can bookmark it for later, really.
   
   
   
  Quote: 





avro_arrow said:


> Both bypassing methods can by used. Some chips respond better to rail to rail bypassing
> and some better to rail to ground. Circuit design also factors into which method is better
> as well.


 

 Any general trends as far as when they respond better to one way or another?


----------



## Tacoboy

Quote: 





shatter said:


> Hello
> 
> I have an Asus Xonar DS, with a JRC5532 opamp for front/headphone output.
> 
> ...


 

 I just replaced my 5532 Op-Amp with an LME49720NA ($6.60 on eBay) on my Xonar DS. which seemed to improve the sound.
  You can try something more fancy, dual 49710HA on a TO-99.


----------



## Avro_Arrow

Personally, I think it has more to do with the quality of the ground.
  If your ground is not so strong (like a virtual ground) then you might
  be better off with rail to tail bypassing but if your ground has a very
  low impedance then I think rail to ground is preferred. It is something
  else to experiment with.
   
  Quote: 





mad max said:


> I wanted the link so I can bookmark it for later, really.
> 
> 
> 
> ...


----------



## LuciferX

TI to acquire National Semiconductor
   
   


Spoiler: Full%20email



Dear valued customer,

 I am excited to let you know that TI has signed a definitive agreement to purchase National Semiconductor, uniting two industry leaders that have a common commitment to solving your analog needs. I want to reinforce TI's commitment to you, our customer, as we merge our two companies.

 This acquisition will allow us to address your analog needs with a product portfolio of unmatched breadth and depth. National's 12,000 products plus TI's 30,000 means more performance, power and packaging options when selecting the right ICs for your application. And we'll provide a common set of best-in-class online tools to make the selection and design process easier.

 Our combined sales and applications team of 2,500 will be larger than any in the industry so we can provide more customers with greater face-to-face support than ever before.

 Our manufacturing operations will offer more capacity to support your growth. TI's fabs and National's available capacity can enable higher production levels.

 While both companies will operate independently pending the close, our goal thereafter is to make the integration process as seamless as possible. No requalification of products will be necessary since National's manufacturing sites will continue to be utilized. Part numbers from both companies will remain the same. There will be no obsolescence of products.

 I'm excited about what the integration of our two companies will mean for you: an unmatched portfolio to meet your analog needs, an extensive sales and applications network to ease the design process, and manufacturing capacity to support your growth.

 You can learn more about the acquisition at www.ti.com/acquire, including answers to frequently asked questions and video messages from TI leaders regarding the acquisition.

 Thank you for choosing TI. I look forward to a great future together.

 Best regards,

 Rich Templeton
 Chairman, President and CEO
 Texas Instruments


   
  So ... what do we need to expect about this?


----------



## Avro_Arrow

Hopefully it will make it easier to get samples from NS...


----------



## Mad Max

Oh wow.


----------



## asak

Have both the muses01 and muses02 in a jdslabs cmoy.
 $75 dollar opamp in a 60 dollar cmoy...
   
  I have quite an assortment of opamps. including a bunch of linear technology( lt1355, 1361, 1364), burr brown 2227, opa2107, analog devices ad823, national lm4562. the muses are better than all to me.
   
  the muses02 has a bass heavy note, and the muses01 is more neutral. Both sound very natural and organic to me. Both seem to be able to cover the whole frequency range very well as opposed to the rest of the opamps (with the exception of the TIs and the national, although the national picks up noise from nearby electronics too easily). CMOY with either muses opamps is better than the ALO RX MK2 I think. However, the ALO is more dynamic.
   
   the muses01 seems to be clipping sometimes in the cmoy due to requiring more juice than what the 9v cmoy can supply. I can't imagine what it can do with a higher voltage.


----------



## Mad Max

Bipolar, eh?
  Expensive as hell, indeed.


----------



## olor1n

Can anyone recommend an opamp compatible with the Audio-GD Fun that has the detail and balance of ada4627-1brz, but with more of an "airy" soundstage? I really like the textured and dynamic presentation of ada4627-1brz. Micro details are brought to light, instruments seem to have more body and are more distinct, and drums in particular have more impact. It's a really good pairing with the HD650.
   
  Unfortunately, my Audioengine A2s don't fare as well. The speakers aren't resolving enough to show how good this opamp really is in the Fun. The layering that's apparent through headphones is lost and what's presented is a congested mess. I'm using the Earth hdam at the moment and its balance and airy soundstage is fantastic with the A2s. It's very good through the HD650 but is a little too polite for my taste. I did prefer the warmer Moon hdam with the HD650, but that doesn't go well with the inherently boomy presentation of the A2s (although synergy is better than with the ada4627-1brz).


----------



## Mad Max

OPA827?
  HA-2525 or TLE2081 might be able to do it.


----------



## i_djoel2000

has anyone here tried muses 01 or muses 8820 with a decent setup? not like cmoy some guy mentioned in couple pages back


----------



## G.Trenchev

Hey guys,
I've ordered some LM4562s
Are they a worthy upgrade over OPA2134 ?Will get them in about three days


----------



## Mad Max

In many ways, yes.


----------



## svyr

i_djoel2000 said:


> has anyone here tried muses 01 or muses 8820 with a decent setup? not like cmoy some guy mentioned in couple pages back




are they seriously $80 ? (digikey)


----------



## miskatcitnamor

Well, Digikey is selling the Muses01 for $75, so yeah... $80 isn't an unreasonable extension after shipping and tax and the odd cap.  The Muses8820 is only being sold in lots of 100 for 4.20 each.


----------



## svyr

miskatcitnamor said:


> Well, Digikey is selling the Muses01 for $75, so yeah... $80 isn't an unreasonable extension after shipping and tax and the odd cap.  The Muses8820 is only being sold in lots of 100 for 4.20 each.




http://www.digikey.com/Web%20Export/Supplier%20Content/NJR_190/PDF/NJR_MUSES02.PDF looking at the datasheets http://www.digikey.com/Web%20Export/Supplier%20Content/NJR_190/PDF/NJR_MUSES01.PDF , the two don't seem remarkable in any way (at least at 1am  ). What am I missing?


----------



## Armaegis

Marketing.


----------



## jaddie

If you're going to spend $80 on an opamp, probably should at least consider the 990 discrete opamp. Beats IC opamps in just about all specs, and can actually drive some real current into a complex load. I use them in mic preamps and line drivers, the work really well. John Hardy is very helpful with applications.

http://www.johnhardyco.com/pdf/990-2007.pdf


----------



## Mad Max

No thanks, ADA4627-1B is free and pumps out pure awesome.


----------



## High_Q

Hey guys.  I recently purchased a batch of opamps for my CMOY, but some do not work.
	

	
	
		
		

		
			




   
  These:  AD797, AD8433, AD845, OPA637
   
  This is my CMOY:  http://www.jdslabs.com/
   
  Right now I'm enjoying AD712 right now.


----------



## Yoga Flame

Those are single channel opamps, so you would need two of each on an adapter for them to work in that CMoy. 
   
  For example:
  http://cimarrontechnology.com/single-to-dualop-ampadapter-dipversionpn021001.aspx
   
  Similar stuff can be found on eBay too.


----------



## High_Q

^Would there be any noticeable difference in using dual single channels?


----------



## Yoga Flame

You may get improved (i.e. reduced) stereo crosstalk since the left and right channels are amped in separate chips. Better soundstage maybe? Many of the high end opamps like OPA637, ADA4627-1, and AD797 only come in the single channel version anyway, so there isn't any way to make a comparison with them.


----------



## Avro_Arrow

Looking for opinions.
  Which amp would serve as a good input buffer for the TPA6120?
  Most amps specs seam pretty pale compared to the TPA.
  The input buffer amp should have a low input bias current.
  This sounds like a job for a JFet amp but Bi-polar is possible
  to if it has low input bias. Singles would be preferable but duals
  could work too. I was thinking OPA827 (I can't afford OPA627)
  or maybe LME49990.
   
  Thanks
   
  Edit: I guess it goes without saying that it needs to be unity gain stable...


----------



## Mad Max

OPA134


----------



## Armaegis

I was just reading about the really fast LM6171 the other day. It has a high input bias though. No idea it it'll work with the TPA6120.
   
  The datasheet uses OPA134.


----------



## Mad Max

Would AD8599 be low enough?
  I know TPA6130A and ADA4841 have really good synergy together (Fiio E5/7).
  Assuming TPA6120 is similar to 6130 in sound.  4841 almost sounds like 8599/8597's twin.
  If not low enough bias, then perhaps THS4082/4081?  TLE2141/2142?
  Then ADA4627-1, which is lower input bias than the rest of these, as well as the best-sounding.  Well, to me it is.
  Oh, and OPA1641/1642.


----------



## Avro_Arrow

I'm leaning more towards the LME49990.
  P-A used an AD8610 to feed the TPA6120
  in his design.


----------



## jcx

Quote: 





avro_arrow said:


> Looking for opinions.
> Which amp would serve as a good input buffer for the TPA6120?
> Most amps specs seam pretty pale compared to the TPA.
> The input buffer amp should have a low input bias current.
> ...


 


  Multiloop composite amplifiers can improve the technical performance of both the input and output amplifiers - think the (locally much abused) concept of "synergy" - the premise of this thread that rolling amps for different "sonic flavors" in some hardware designed by someone else is not relevant if you're designing/building for yourself and can use more sophisticated circuit topology
   
  the TPA6120 is better than a Buffer chip as output amp in a Multiloop composit amplifier because the TPA allows for gain in the loop - further relieving the input amp of work, actually increasing the input amp linearity as well as increasing loop gain


----------



## Avro_Arrow

Yes, I agree. I was considering whether or not to use a single or a multi-loop
  feedback but I think I will try it multi-loop. I'm looking for more of a "lack"
  of sonic signature. My goal is just to accurately reproduce what was recorded.
  As the TPA has a high input bias requirement, it is best driven from from a
  buffered input or low impedance source. Seeing as I cannot predict what the
  amp may be hooked up to, it is best to buffer the input. I'm just looking for
  the best chip for this buffer that will match the TPA's high specs.
   
   
  Quote: 





jcx said:


> Multiloop composite amplifiers can improve the technical performance of both the input and output amplifiers - think the (locally much abused) concept of "synergy" - the premise of this thread that rolling amps for different "sonic flavors" in some hardware designed by someone else is not relevant if you're designing/building for yourself and can use more sophisticated circuit topology
> 
> the TPA6120 is better than a Buffer chip as output amp in a Multiloop composit amplifier because the TPA allows for gain in the loop - further relieving the input amp of work, actually increasing the input amp linearity as well as increasing loop gain


----------



## psgarcha92

Guys,
  what opamp should i use to drive iems? mine are the RE ZEROs, also going to use the amp with the RE0s.
  i need transparent and bassy (in separate opamps) here.
  Thanks


----------



## High_Q

Are there any frequency response charts of opamps?


----------



## Avro_Arrow

The manufacturers data sheets are full of nice charts and specifications...

  
  Quote: 





high_q said:


> Are there any frequency response charts of opamps?


----------



## Mad Max

Quote: 





psgarcha92 said:


> Guys,
> what opamp should i use to drive iems? mine are the RE ZEROs, also going to use the amp with the RE0s.
> i need transparent and bassy (in separate opamps) here.
> Thanks


 

 What amp?


----------



## psgarcha92

A CMoy, buffered and not buffered.also a Mini^3 if opamp rolling is possible there.


----------



## devast

Quote: 





avro_arrow said:


> Personally, I think it has more to do with the quality of the ground.
> If your ground is not so strong (like a virtual ground) then you might
> be better off with rail to tail bypassing but if your ground has a very
> low impedance then I think rail to ground is preferred. It is something
> else to experiment with.


 


  Those are my opamps, it's funny seeing them linked 100 pages later 
	

	
	
		
		

		
		
	


	



  About the caps... i wanted a bypass as close to the ICs as possible. You might bypass to ground on the adapter, if the negative/positive inputs of the opamps are grounded in your circuit (they are not, in mine). So it's not just what's better, but what's doable.
  There are bigger(0,1uf) bypasses to ground under the pcb as well. As to why did i do it... well, it won't hurt that's for sure, and i wanted to eliminate any chance, that my opamps start oscillating because of the power supply, since i don't have the tools to measure (and debug) it.


----------



## Bacci

After spending a lot of time listening to OPA627 on my M³, I plugged in Browndogged OPA1641's. 
  In general I would say it's an improvement for most genres, with the highs now a little less harsh and the mids more forward it gives an overall more balanced sound. 
   
  Not sure I would recommend OPA1641 over the OPA627 for electronic music, though. The OPA1641 doesn't come near OPA's 627's precise and hard bass. The highs seem less harsh/tiring, but at the same time miss the pinpoint accuracy of the OPA627. Electronic sounds muddier as a result.
   
  Would love to hear some other opinions!


----------



## Dhimay

I have a Firestone Fubar III amp/dac on the way, with stock opa2604 in the amp module, and lm4562 in DAC. I'm hoping I could get some recommendations to upgrade the stock opamp.
   
  * Power - 24V 0.5A Auto-switching
   
  This will be my first amp/dac unit, and l will be using it with Denon D2000, through mac mini.
  I'm looking to tame the somewhat strident highs of D2k, bring out the mids, improve the soundstage, and harness the bass (i.e. increase speed and impact); in other words, looking for synergy.
   
  My only consideration so far is the dual opa627 combined on a single PCB (note: this has been tested and recommended/sold by "audiophileproducts.com" -- North American distributor of Firestone audio), possibly with a class A biased mod; although not sure whether this will yield any perceivable improvement with my modest setup. From I understand, it seems to be an improvement for Matrix M-Stage.
   
  Any suggestions.


----------



## SabreWulf69

OPA2111 or OPA2107? Got some 2132's on order, so far tried the LME49720NA's, the 4562's, the LT1364's and the 2107's. These all seem like the most popular going around these parts nowadays, what's people experiences with the different sorts of sounds from these OPAMP's mentioned? I am primarily interested in use for speakers, but this forum seems to be the best for OPAMP advice regardless whether it be for headphones or for speaker playback. I like one's that have a nice boring and flat yet fairly detailed sound and precise soundstage to them as the rest of my gear is very neutral and will put through what is sent to it without colouration.
   
  Also has anyone tried the OPA1612's or OPA1602's yet?


----------



## leobigfield

Hi guys.
   
  I was thinking about changing my fiio e5 op-amp so i need some advice...
  I have an Ortofon E-Q5 on the way, so i was thinking about something that could give me a little boost on the bass...
  What do you think? It's my first top-tier IEM, so i don't know exactly what should i expect... I read that the e-q5 is somewhat lite in the bass, and since i come from the Klipsch S4 i thought that should help... My source is a Clip+ player.
   
  Thanks!


----------



## sinae

Im about to mod an RME 9632 and an SM Pro Audio M-patch 2 volume control . Beside changing the caps I wanted to change the opamp on both and also the clock on the Rme. I was wondering if any of you smart guy wanted to guide me a little in my first quest to modding.
   
  I decided to create another thread on this topic so that i will not overstep this one..
  please if your interested i would greatly appreciate your help
http://www.head-fi.org/forum/thread/566627/best-opamps-for-my-rme-9632-and-m-patch-2-mods-need-help#post_7671258


----------



## brat

Hi,
  I'm new to this op-amp rolling and definitely not a DIY-er.
  Please, recommend me some op-amps with rolled-off highs and more "analog" sound for my Audio-GD FUN.
  Now I'm listening to AD826AN. It's pretty well balanced and have a tolerable peak in the lower highs. Yesteday I've tried LME 49720HA (very agressive highs) and LT1469 which has the desired roll-off at the top end but also a drop in lower bass which doesn't fit my tastes.


----------



## sinae

Not sure but ive seen on a site that AD827SQ is one of the best opamp for electronic music
   
  up there with ADA4627-1ARZ
  LME49990MA 
   
  Anybody heard the
  AD 847AQ
   
  Anybody have opinions on this?


----------



## SpudHarris

Quote: 





sinae said:


> Not sure but ive seen on a site that AD827SQ is one of the best opamp for electronic music
> 
> up there with ADA4627-1ARZ
> LME49990MA
> ...


 

 I agree that the AD827 is indeed great with electronic genre.
   
  I prefer the ADA 4637-1BRZ and my new best favourite OPA602BP 
   
  My long time love of OPA2111KP or OPA111BM (metal can) continues
   
  Food for thought.


----------



## sinae

what about dual
 Analog Devices AD797ARZ compare to those   
  you said
  I prefer the ADA 4637-1BRZ and my new best favourite OPA602BP 
   
  My long time love of OPA2111KP or OPA111BM (metal can) continues
   
  where can i find those
   
  i would really appreciate if you could help me with my m-patch2 mod
  http://www.head-fi.org/forum/thread/566627/best-opamps-for-my-rme-9632-and-m-patch-2-mods-need-help#post_7671258


----------



## SpudHarris

You need to search on here for info and also look at Digikey / Mouser / Farnell / RS componets etc.. for pricing.
   
  OPA209 is also a great OpAmp if implemented correctly (5 off are used in 2Stepdace).


----------



## madwolf

I listening to OPA2209 on my portable amplifier as I typed this, 
  This is truly a remarkable OP-AMP, Was woundering why nobody mention this sooner. A remarkable find 
   
  But on some system it could be a ted sensitive.
  
  Quote: 





spudharris said:


> You need to search on here for info and also look at Digikey / Mouser / Farnell / RS componets etc.. for pricing.
> 
> OPA209 is also a great OpAmp if implemented correctly (5 off are used in 2Stepdace).


----------



## SpudHarris

Yeah, it's one that needs a bit of listening to before you realise how good it is. There are a few fans but I only heard about it a few months back when Ryuzoh paid me a visit. Another he recommends is the OPA602BP and I also agree that this is a fantastic chip...


----------



## sinae

there seems to be no way to really have information on how to mod my M-Patch2 with another better opamp.
   
  I made a new topic but it seems nobody here is interested in sharing their knowledge 
http://www.head-fi.org/forum/thread/566627/best-opamps-for-my-rme-9632-and-m-patch-2-mods-need-help#post_7671258
   
  here a part of my topic
  M-Patch2
  current dual opamp = NJM4558L In SIL 8pin format
  also another opamp on the board near the output jack = njm4556al in sil 8pin also.. I wonder what both are doing anybody have an idea
  current voltage regulator = L7812CV
  caps = TFY caps
   
  M-Patch2 modded
  opamp = SIL single-to-dual Op-Amp Adapter + opamp
http://cimarrontechnology.com/silsingle-to-dualop-ampadapterpn040701.aspx
   
  dual OPA627AU, dual OPA827AI, dual LME49990, dual AD797ARZ, dual AD797BRZ
   
  So now I need to know if its a drop in replacement or if for the best sound quality I need to also modify something else in both 
   
  Also I need to know what opamp is the best in those.
   
  I'm a DJ and composer of electronic music and this will be coupled with Beyer T1 600ohm headphones and DT250 80ohm. I will buy a tube amp for the T1 but for now i decided that those cheap opamp need to go  ..
   
  In the M-Patch 2 im not sure if other part of the headphone should'nt be upgraded too. It seem to be a very simple design 
  see
http://www.gearslutz.com/board/low-end-theory/443788-m-patch-2-anyone-successfully-mod-thing.html
   
   
  --------------


----------



## Avro_Arrow

If you are not getting any responses, it is probably because people don't have
  any experience with this piece of equipment. Maybe if you could post some
  pictures of the "guts", both sides of the board would be good, we could get
  some idea of the circuit and how it might be improved.
  
  Quote: 





sinae said:


> there seems to be no way to really have information on how to mod my M-Patch2 with another better opamp.
> 
> I made a new topic but it seems nobody here is interested in sharing their knowledge
> http://www.head-fi.org/forum/thread/566627/best-opamps-for-my-rme-9632-and-m-patch-2-mods-need-help#post_7671258
> ...


----------



## sinae

Its quite simple, on top you have the power input plug + resistance + input cap and L7812CV voltage regulator.. You can see those clearly
   
  Afterwards you have some resistances, caps and the first opamp of the chain NJM4558L and theres others caps on the left
  just before the headphone output at the bottom theres another opamp njm4556al
   
  and thats it mostly it.. So I need to understand what those opamp are doing and if they can be replaced for better one to give me a good headphone amp
  I could replace the caps and resistance with better ones also but thats another simple matter.
   
  it seems to be one of the most simplest headphone amp design.
   
   

   
  from the other side where you can see at the top the headphone out quarter inch plug
   

   
  here the voltage regulator so that you can recognize it in those pics


----------



## Avro_Arrow

It's pretty hard to give good recommendations without knowing the basic schematic.
  I could guess that the 4558 is the gain block and the 4556 is a buffer.
  It looks like they used a single ended power supply so the outputs are probably
  capacitor coupled. of course, that may not be it at all...
  Another potential problem is that if the board was not designed for high performance
  amps, they may behave badly in this design.
  The bottom line is that there may be some worthwhile upgrade or you may just be
  better off getting an dedicated headphone amp like a (insert you favorite amp here).


----------



## SabreWulf69

Quote: 





spudharris said:


> I agree that the AD827 is indeed great with electronic genre.
> 
> I prefer the ADA 4637-1BRZ and my new best favourite OPA602BP
> 
> ...


 


  Tried the OPA1611's or the AD823's?


----------



## SpudHarris

OPA1611's are really nice and with the class A tweak have massive air and detail.
   
  AD823 is what the GS Solo uses so I guess Graham Slee holds it in great regard. For me? I don't think it's a great chip for rolling into a circuit not optimised for it's specific use.
   
  Said it before, you guys are missing a trick with the OPA602..... You have to try it! and don't give it 5mins (I'm guilty of that sometimes). I tried it and wasn't immediately impressed which I am sometimes with some of the snappy AD chips but went back to it and now it is a perminant fixture in my Fi-Quest and P4 and when my EF-5 gets here, probably in that too.


----------



## EpicPie

Noob question, how do I determine what opamp I have in my CMoy?

 Another member(Vixr) built my CMoy for me. lol


----------



## SpudHarris

Should be one of these little fellas in there. Then on the top it will tell you what it is - OPA2227 - OPA2134 for instance
   
  Post a pic!


----------



## sinae

Quote: 





spudharris said:


> OPA1611's are really nice and with the class A tweak have massive air and detail.
> 
> AD823 is what the GS Solo uses so I guess Graham Slee holds it in great regard. For me? I don't think it's a great chip for rolling into a circuit not optimised for it's specific use.
> 
> Said it before, you guys are missing a trick with the OPA602..... You have to try it! and don't give it 5mins (I'm guilty of that sometimes). I tried it and wasn't immediately impressed which I am sometimes with some of the snappy AD chips but went back to it and now it is a perminant fixture in my Fi-Quest and P4 and when my EF-5 gets here, probably in that too.


 

 what would you recommed between OPA602 and OPA1611(class A Tweak) in my M-Patch.. What should i use in the buffer stage for those to replace my NJM buffer


----------



## sinae

http://www.cadeka.com/NJM4558.php
   
  here somebody replaced NJM4556 with LME49860
http://www.esnips.com/web/X-FIOpAmpandCapModification
   
  so maybe LME49990 would be a good choice to replace NJM4556AL in buffer stage
  OR Buf204?


----------



## Mad Max

BUF204?


----------



## sinae

humm BUF634 maybe  anyway hihi


----------



## Tacoboy

LME49990MA op-amps
  Has anyone tried the LME49990MA op-amps in the Asus Xonar Essence STX?
  If so, how was the sound quality?


----------



## sinae

Not a lot of post on that one. I would also like to know a little more about that opamp..


----------



## Mad Max

Who's been playing with OPA1602?


----------



## ecclesand

Quote: 





mad max said:


> Who's been playing with OPA1602?


 


  I popped a set in my DAC (I/V and Buffer) and let them burn in for a few hours.  On first listen, I think these are going to be very good.  Solid clarity and good instrument separation with a somewhat laid back presentation.  They remind me of the OPA827.


----------



## Mad Max

It seems to be more natural-sounding somehow than any opamp I've tried so far.  It does indeed resemble OPA827 to an extent.


----------



## i_djoel2000

what are the options for good jfet dual opamps with soic socket (beside ad8620)? i'm planning to mod my dacmagic
	

	
	
		
		

		
		
	


	



   
  how's opa1642? does it have better treble extension, soundstage, and bass than LME49720?


----------



## ecclesand

Yes, natural....they just sound.....right.


----------



## Mad Max

i_djoel2000 said:


> what are the options for good jfet dual opamps with soic socket (beside ad8620)? i'm planning to mod my dacmagic
> 
> 
> 
> ...




I don't think that I will ever like 49720. =\
1641/1642 is good, and its soundstaging puts 49720 to shame.


----------



## i_djoel2000

Quote: 





mad max said:


> I don't think that I will ever like 49720. =\
> 1641/1642 is good, and its soundstaging puts 49720 to shame.


 

 thanks for the reply..
   
  how about its treble and bass extension, details, etc.? is it better than 49720 as well?


----------



## Mad Max

That will depend on the circuit, and I've never played with the DACMagic, but I imagine it should be great.


----------



## i_djoel2000

Quote: 





mad max said:


> That will depend on the circuit, and I've never played with the DACMagic, but I imagine it should be great.


 


  true..
   
  but at least with rolling opamp using the same circuit, you can get the general sound signature of the opamp, given the voltage supply is adequate


----------



## misha0209

hello all,
   
  long thread, did not read all of it, but i did use the search function to try and find answers to what i'm about to ask. found some, but a straight answer would help.
   
  so i have an asus xonar essence st.
  i've started trying opamps, and so far the best combo i could come up with was opa2228 in i/v and lt1057 as buffer (A). nice smooth sound, nice sound stage good positioning.
   
  then i swapped the lt1057 in the buffer with a lme49720na (i have the HA but my adapters did not arrive yet) (B). sound was amazing, wide soundstage, all instruments are separated. one bad thing though, everything seem to have been brought to front, more of a 2d soundstage if you will. in games, with (A) i had an accurate idea of what was arround me from what i could hear, with (B) i had an enemy behind me, and the sound was telling me to look front, up, left. no positioning whatsoever.
   
  so, i want to ask if the HA provides the same soundstage. also, it would be lovely if someone recommended me opamps that have a more 3d soundstage. and lastly do the HA's perform better as i/v or buffers?


----------



## qusp

hehe not gonna get a straight answer to such a subjective question. personally, i dont find the HA to sound very different at all, its mainly better for temperature stability and emf shielding


----------



## qusp

Quote: 





i_djoel2000 said:


> true..
> 
> but at least with rolling opamp using the same circuit, you can get the general sound signature of the opamp, given the voltage supply is adequate


 


  no, even that is a generalization, different chips will have different input stage styles (jfet, fet, bipolar), prefer different feedback setups, different decoupling, some may have special purpose pins for reducing noise, sound better or prefer higher gain, or need bandwidth limiting for stability etc etc.
   
  so 'rolling' a chip into the place of an opamp that has special needs, perhaps utilizing pins that are unused normally, setup for low or perhaps even unity gain, may result in a circuit that is entirely sub-optimal and sound quite bad, although the chip rolled in, may in fact be a much higher performance chip, but rolled into a circuit with the incorrect operating point, sound not so good


----------



## genclaymore

I trying out OPA2111AM in my Fiio E9, I liking it so far, Tho I liked the details more on the LT1364. Having a sinus in my ear ruining my fun until it goes away. I also wanted to put LT1028 instead of the LT10364 but the adapter I have is uneven and will not fit as it will hit the headphone 6.3 out in the Fio E9. I do have 1057 which i pretty sure are single opamps from what I remembered. I also liked the OPA2107AP in the amp.  I would try out the LME 49720HA in it but i fiqure  another LME 497#0 even if its the can ver in the end with 2x LME 49720NA and 2x LME49710NA in my X-Fi HD pcie would be bad combo.


----------



## danny93

Looking for opamps for a titanium HD, bass is really important, then highs, then mids what do you think the best option would be? (listen to allot of chilled dubstep, some vocal dubstep also, and Drum and bass)
   
  I have heard this setup could be nice: LME49860NA or AD797BR  in I/V and OPA627BP in the buffers ?
   
  Thanks in advance!


----------



## Mad Max

How much does OPA209/2209 benefit from class-A biasing?


----------



## SpudHarris

^ Not any real benefit, a bit more airy I guess.
   
  Bit of Opamp P o r n ! Just reorganised my better chips...


----------



## Mad Max

So little pr0n?


----------



## SpudHarris

I've gathered literally 100's but those in the pic are what I roll/use on a regular basis.....
   
  OPA602BP RULES!!!!


----------



## Mad Max

Quote: 





spudharris said:


> ...
> OPA602BP RULES!!!!


----------



## SpudHarris

To what??


----------



## dw1narso

I just tried OPA2209 and OPA1642 as unity gain buffer in front of TPA6120. Those new OPA are really special.

OPA2209 is really the result of new development on material. Though bipolar, the DC offset is equaling FET/J-FET opamp. OPA2209 has the magical mid.

OPA1642 has better technical aspects (attack, speed, detail, etc.) but cannot beat 2209 on human voice.

And kudos to TPA6120 too. This current feedback small power opamp is really transparent to show whatever buffer in front of it.


----------



## dw1narso

spudharris said:


> ^ Not any real benefit, a bit more airy I guess.
> 
> Bit of Opamp P o r n ! Just reorganised my better chips...





Impressive... but I think opamp is not a good investment since their price will degrade by the time... 

tubes, especially the old ones, are better investment... :evil:
(oopsss OOT)


----------



## SpudHarris

Quote: 





dw1narso said:


> Impressive... but I think opamp is not a good investment since their price will degrade by the time...
> 
> 
> 
> ...


 

 OpAmps generally cost less to begin with in comparison and as they take up so little room I tend to keep them and only shed inventory when I shift an amp.
   
  There are thousands of 6SN7 variants costing very little that will never be worth anything more. I got rid of my WA6 just recently but kept a genuine pair of Sylvania 'Bad Boys' and a pair of 1942 Tung-Sol Black Glass Round Plates


----------



## dw1narso

spudharris said:


> There are thousands of 6SN7 variants costing very little that will never be worth anything more. I got rid of my WA6 just recently but kept a genuine pair of Sylvania 'Bad Boys' and a pair of 1942 Tung-Sol Black Glass Round Plates




You're a man of hi taste


----------



## SpudHarris

Thank you Sir!
   
  Does anyone here know much about the HA5002 buffers? I'm using BUF634P (Hi-C) and stacked BUF634U's but I'm lead to believe the HA5002's are better. I can't find them on Farnell....


----------



## Mad Max

There are several places to get it in the US, and in several grades.
  I doubt it can beat BUF634, but who knows.


----------



## Lavcat

Quote: 





robscix said:


> Quote:
> 
> 
> Originally Posted by *Lavcat* /img/forum/go_quote.gif
> ...


 


 I finally got around to doing an experiment.  Tonight I soldered up a new set of BrownDogs using Central Semiconductor 1N5314's from outputs of the OPA627BM's to -Vs.  No smoke came out and after a couple hours of listening I am quite pleased with the sound.  I can't do any quick A/B comparison however.
   
  Has anyone else tried class A biasing?


----------



## nivrethejugg

Sorry if it's already mentioned but how is class A biasing done?


----------



## Fred_fred2004

Have a look at
   
http://www.tangentsoft.net/audio/opamp-bias.html
   
  cheers


----------



## SpudHarris

220ohm resistor between pins 6 and 7 on single opamps. Don't know about duals...


----------



## ostewart

hey, can anyone in the EU put togther a selection of opamps to use with a DIY MIU amp, it only uses one opamp, so im guessing its a dual opamp. If anyone can put together a selection of good opamps, plus shipping to portugal for 20-30 euros PM me. Thanks


----------



## nivrethejugg

Quote: 





fred_fred2004 said:


> Have a look at
> 
> http://www.tangentsoft.net/audio/opamp-bias.html
> 
> cheers


 
  Quote: 





spudharris said:


> 220ohm resistor between pins 6 and 7 on single opamps. Don't know about duals...


 

  
  Thanks. Will try to find out more about them. Thinking of doing it on opa1611s or opa209s. Should I get Browndogs or those on ebay?


----------



## SpudHarris

I've been using these (below) from Hifi Audio IC (e-bay) and they are as good as I've used and better than many. Use as a single or a dual.
   
  And for the record the OPA1611 is the best opamp with the Class A tweak, it's beautiful. I didn't notice any difference with the 209 at all.
   
  I make a DIP socket into a Class A adapter then you can plug any opamp you want into it. Solder a 220ohm underneath one of these and away you go. I'll post a pic later, I have posted some earlier in this thread but can't be arsed to dig out the page...


----------



## jcx

Quote: 





spudharris said:


> 220ohm resistor between pins 6 and 7 on single opamps. Don't know about duals...


 


 220 Ohm is too heavy a load for most op amps
   
  Class A  operation depends on the load seen by the op amp, which requires signal level and load impedance to calculate, then supply V has to be taken into consideration - and you don't want to run most op amps outputs at even 1/2 of their current rating to keep gain high, distortion low - so there is no "one size fits all" resistor or current source/sink "Class A bias" solution
   
  if the op amp has a shunt supply regulator you could even pull too much current and loose the regulation - circuit mods really need to be done with knowledge of the surrounding circuits, operating conditions, not blindly


----------



## Lavcat

Quote: 





nivrethejugg said:


> Sorry if it's already mentioned but how is class A biasing done?


 


  
  For the 627's I installed the current regulator diodes from pin 6 (output) to pin 4 (-Vs).  On the BrownDog adapters there was just enough room for the parts.


----------



## ecohifi

opps, trigger happy on submit


----------



## ecohifi

Quote: 





olor1n said:


> Can anyone recommend an opamp compatible with the Audio-GD Fun that has the detail and balance of ada4627-1brz, but with more of an "airy" soundstage? I really like the textured and dynamic presentation of ada4627-1brz. Micro details are brought to light, instruments seem to have more body and are more distinct, and drums in particular have more impact. It's a really good pairing with the HD650.
> 
> Unfortunately, my Audioengine A2s don't fare as well. The speakers aren't resolving enough to show how good this opamp really is in the Fun. The layering that's apparent through headphones is lost and what's presented is a congested mess. I'm using the Earth hdam at the moment and its balance and airy soundstage is fantastic with the A2s. It's very good through the HD650 but is a little too polite for my taste. I did prefer the warmer Moon hdam with the HD650, but that doesn't go well with the inherently boomy presentation of the A2s (although synergy is better than with the ada4627-1brz).


 


 Try the AD 825, very airy but lacks bass resolution compared to the ADA 4627-1a


----------



## ecohifi

Quote: 





olor1n said:


> Early impressions of the ada4627-1brz in my setup are very positive. There's amazing detail, effortless clarity in dynamic passages, drums have impact and snap, and bass is very well defined in the balanced presentation. This may have just replaced Moon as my preferred opamp in the Fun for the HD650.


 

 olor1n,
   
  how does the earth, moon and sun compared to the ada 4627-1BRZ???


----------



## i_djoel2000

hello, sorry for hijacking this thread. anybody knows where i can buy dual soic to soic adapter with cheap shipping fee? i live in South East Asia..


----------



## danny93

Hi guys,
   
  Just bought a Titanium HD and trying to decide what opamps to use...
  Have these on the way: OPA2134,2111KP,LME49720 (HA and NA),AD797ANZ with the LME49710NA already stock in the buffers.
   
  So what setup would be best for chilled vocal dubstep like http://www.youtube.com/watch?v=sDI6HTR9arA (i know not a common type of music but i like it ) I have dt770 cans which have recessed mids so perhaps something which could bring those out could work well but im not sure...
  Great bass is also a must 
   
  Thanks allot guys and gals


----------



## ostewart

im looking for a dual Opamp, for a cmoy type amp, clean, balanced sound, quick attack, so no burr brown sound.


----------



## ostewart

its got a standard opamp socket, so if i need an adapter tell me. If i can get it all on ebay, better.


----------



## Tommy Thong

try lme49720ha / lme49720na


----------



## danny93

Quote: 





tommy thong said:


> try lme49720ha / lme49720na


 


 Hi are you talking to me or RandomKid mate?


----------



## Mad Max

Quote: 





ecohifi said:


> olor1n,
> 
> how does the earth, moon and sun compared to the ada 4627-1BRZ???


 

 It's like comparing HD800 to $3 earbuds.
   
   
   
   
  I'm kidding.
   
  ADA4627-1B offers more clarity, extension, resolution, control, precision, transparency, body, and better layering and speed.  It is also energetic like OPA Sun and more neutral than even Earth, which quite frankly, isn't neutral.  (Somewhere along the way in the past two years, it went from "closest to neutral" to downright "neutral" even though there's been no change in the design if I am not mistaken.  People today still find it colored versus neutral chip opamps.)  4627's soundstage is deeper than those others as well.  It's really not a fair comparison, I think.  I've been having loads of fun with it. (No pun intended.)


----------



## rhythmic_impulse

Quote: 





mad max said:


> It's like comparing HD800 to $3 earbuds.
> 
> 
> 
> ...


 


  Hi Mad Max,
   
  What is the capacitor that you used for the power supply bypass in the picture? It looks like a Vishay-Roderstein MKP1837 1uf. Is that the best for th4627-1B?


----------



## Tommy Thong

Quote: 





danny93 said:


> Hi are you talking to me or RandomKid mate?


 


  
  to RandomKid, my friend


  Quote: 





danny93 said:


> Hi guys,
> 
> Just bought a Titanium HD and trying to decide what opamps to use...
> Have these on the way: OPA2134,2111KP,LME49720 (HA and NA),AD797ANZ with the LME49710NA already stock in the buffers.
> ...


 


 do you try opa211-ID yet? coz' they have deep bass sound too


----------



## SpudHarris

Quote: 





mad max said:


> ADA4627-1B offers more clarity, extension, resolution, control, precision, transparency, body, and better layering and speed.  It is also energetic like OPA Sun and more neutral than even Earth, which quite frankly, isn't neutral.  (Somewhere along the way in the past two years, it went from "closest to neutral" to downright "neutral" even though there's been no change in the design if I am not mistaken.  People today still find it colored versus neutral chip opamps.)  4627's soundstage is deeper than those others as well.  It's really not a fair comparison, I think.  I've been having loads of fun with it. (No pun intended.)


 

 Mad Max - Are those metal cans 602CM? Can't think of another opamp that ends ''02CM'' What do you think of them? I got 4 off them a couple of months back, they are very, very hard to find these days.... I don't like them as much as the BP version. Dunno, something seems missing. Very detailed, holographic with a massive soundstage but just don't grip me the way the BP's do. Be interesting to hear what you think.


----------



## SpudHarris

I've been messing around trying to find a way to test different caps?


----------



## murrays

Quote: 





spudharris said:


> I've been messing around trying to find a way to test different caps?


 
   
  I know it's a bit of a hassle, but try to keep the leads as short as possible.  Long leads can cause HF instability and oscillations.  These may mask the true differences between the caps.  Soldering directly across the pins of the chip is best, but I realise that you want a practical method of swapping them quickly.  I have seen adapters in the past that had positions for capacitor mountings on them.  Either that, or solder turned-pin sockets directly to the chip/adapter.


----------



## Mad Max

Quote: 





rhythmic_impulse said:


> Hi Mad Max,
> 
> What is the capacitor that you used for the power supply bypass in the picture? It looks like a Vishay-Roderstein MKP1837 1uf. Is that the best for th4627-1B?


 

 Yes they are.  I love those caps, but there are others you can try as well.  There is also a small 12pF ceramic on the underside.  It should be 1pF or so, but I don't have any of those on hand at the moment.
   

  
  Quote: 





spudharris said:


> Mad Max - Are those metal cans 602CM? Can't think of another opamp that ends ''02CM'' What do you think of them? I got 4 off them a couple of months back, they are very, very hard to find these days.... I don't like them as much as the BP version. Dunno, something seems missing. Very detailed, holographic with a massive soundstage but just don't grip me the way the BP's do. Be interesting to hear what you think.


 

 Yup, 602CM indeed.  =]
  Yes, I noticed the same thing... perhaps too many odd harmonics being emphasized?  It doesn't sound natural for some reason.  BP sounds less unnatural.  After some tinkering, I expected 602CM and 797BR to come out on top as best opamps to me, but I am instead preferring 4627-1B and OPA827 over 797 and 602CM.  4627 most especially blows me away with its thick, ultra-refined, analytical-to-death sound, not to mention energetic.  I am never going without caps again; oscillation really blows, lol.  I didn't even like 797 before, and now its one of my favorites.
   
  I don't like those WIMA MKP - too colored and rounded.  Have you tried EVOX/RIFA caps?  ERO MKP1837 are clearer, much more balanced, more precise, and cleaner than the WIMA MKP.  I've put them into my M-Stage amp as well.  Fantastic for power decoupling/bypassing and what not.  They're even an upgrade over the stock bypass caps on A-gd's HDAMs.


----------



## danny93

Nope i havent traied any opamps yet, those listed are on the way...is the OPA2111KP any good?
   
  Cheers mate

  
  Quote: 





tommy thong said:


> to RandomKid, my friend
> do you try opa211-ID yet? coz' they have deep bass sound too


----------



## Tommy Thong

Quote: 





danny93 said:


> Nope i havent traied any opamps yet, those listed are on the way...is the OPA2111KP any good?
> 
> Cheers mate


 


  OPA2111kp is dual channel of OPA211, they're almost the same sounding( n strong @ Bass too)


----------



## SpudHarris

Quote: 





tommy thong said:


> OPA2111kp is dual channel of OPA211, they're almost the same sounding( n strong @ Bass too)


 

 OPA2111 is the dual channel version of OPA111 not OPA211 and to my ears they don't sound alike


----------



## ostewart

ok, just ordered 1xAD823AN and 1xLME(the one that was mentioned earlier), lets see what they are like.


----------



## ecohifi

Quote: 





i_djoel2000 said:


> hello, sorry for hijacking this thread. anybody knows where i can buy dual soic to soic adapter with cheap shipping fee? i live in South East Asia..


 


  
  Try http://cimarrontechnology.com/audioupgradeadapters.aspx


----------



## i_djoel2000

Quote: 





ecohifi said:


> Try http://cimarrontechnology.com/audioupgradeadapters.aspx


 


  thanks, mate


----------



## ecohifi

Quote: 





mad max said:


> It's like comparing HD800 to $3 earbuds.
> 
> 
> 
> ...


 

 Mad Max
   
  Those $3 earbuds must be good, I should try some!!!! LOL
   
  would you say that the ADA 4627-1 BZ is one of the best in your collection.  Have you compared it to the Bursons or the Dexa?
   
  I have the BB 827, 627 1611 1641,LT 1122 LME 49990, AD 825 and ADA 4627-1 A,  I have just received the ADA 4627-1 B and as far as I am concern these are more focused than the A version and well worth the price.  I think the clarity and transparency just bested the rest in my collection.  What I am trying to established is whether it is worth going Audio gd Sun, Bursons or DEXA.  Or is the ADA 4627-1 bz   up there in terms of  accuracy in microdetails?


----------



## Mad Max

I'd be surprised if 4627 didn't beat them.  I haven't tried the Dexa, and I seriously doubt it can beat 4627.


----------



## Mad Max

I didn't throw away the stock bypass caps (EVOX RIFA 480nF) that were on Sun, so I added them to 797 and 4627.  I'm not liking it, softens things too much for my liking, but otherwise good.


----------



## SpudHarris

I've been a long time fan of the 4637BRZ, I must dig out the 4627's and have another listen.
   
  Mad Max - Have you tried OPA602BP? must be BP. I love this chip so much I bought every version (except BM) to see if there is anything that betters the BP, none do. I'm considering dropping £60 on a couple of BM's now, any experience with them?


----------



## ecohifi

Quote: 





spudharris said:


> I've been a long time fan of the 4637BRZ, I must dig out the 4627's and have another listen.
> 
> Mad Max - Have you tried OPA602BP? must be BP. I love this chip so much I bought every version (except BM) to see if there is anything that betters the BP, none do. I'm considering dropping £60 on a couple of BM's now, any experience with them?


 

 SpudHarris,
  can see why yu like the OPA 602 BP, Bias is 1pA, CMRR isn't as good as the 4627.  Haven't experience them yet but according to the data sheet the BM version is no longer made, how are you getting hold of them?
   
  Originally I had the 4627-1 A for a while but didn't impressed me initially compared to the AD 825.  A second listened mths later with the volume cranked up painted an impressive picture that gets closed to real sound with better clarity in microdetails that prompt me to order the B version.


----------



## ecohifi

Quote: 





mad max said:


> I didn't throw away the stock bypass caps (EVOX RIFA 480nF) that were on Sun, so I added them to 797 and 4627.  I'm not liking it, softens things too much for my liking, but otherwise good.


 

 These EVOX Rifa that Audio GD uses are not MKPs, try the Vishay MKP 1857 range!!!


----------



## SpudHarris

I actually see the BM version crop up on the bay periodically but would only ever buy something like that from a trusted source. I've had good experience with Audio Jade.... I have the CM version which I'm told is the best (going from the data sheet) but it just seems lacking something in the mids that the BP just does so well. The CM is very holographic, quite airy in comparrison to the BP and has an initial ''Wow'' factor but I soon tired of it.
   
  I'm also liking the OPA1641's at present.


----------



## Mad Max

I have the BP, it was the first one that I tried out.  I'm preferring the CM more recently.  A replaced the bulk bypass (MKP1837) with a 10uF tantalum, and it stopped sounding so unnatural plus a little better.
  I have only tried BP and CM so far, and I'm not interested in any more 602 versions right now.
   
  I would tinker with 4637, but I figure that once I meet its gain requirement and add a large enough bandwidth-limiting cap, it will sound the same as 4627.
   
   
  I take it these grey RIFA caps are the polyster kind instead?  Go figure.  I'll give those 1857 a go later.  Have you tried the 1839 series?


----------



## ecohifi

The grey Evox caps are MKT, if you have the 1839 no point in trying the 1837!!!   I have not tried the 4637 and possible not going to because all my stages have gains less than 3,


----------



## DefQon

Any of you's know or have experience of what the best OPamp is that will work with a Banzai v2 kit that runs on dual 9v batteries providing a 18v rail?


----------



## ostewart

LME 49720NA - just put it in my miu audio amp, it is very nice sounding, very natural, gives the sound more air and more space, bass goes deeper, but also makes it sound more musical. im really liking this opamp compared to the stock that came with the MIU amp. now awaiting my AD823, see what thats like.


----------



## ostewart

i saw people saying that the LME i have is harsh sounding in some soundcards, but in my portable amp it isnt, it is detailed, natural sounding, gives a bit more body to the bass, but overall a very nice sounding opamp.


----------



## murrays

Quote: 





ostewart said:


> i saw people saying that the LME i have is harsh sounding in some soundcards, but in my portable amp it isnt, it is detailed, natural sounding, gives a bit more body to the bass, but overall a very nice sounding opamp.


 
  I agree too.  I have been running a LME49720 in my stand-alone amp for the last few months and have noticed the added detail and clarity.  I suspect that the complaints about harshness may be due to it revealing undesirable aspects elsewhere in the system.  I believe it depends a lot on the quality of its power supply.


----------



## ostewart

my iPod has mainly 320kbps or apple lossless for the music i really like, some others are lower bit rate but havent listend to them yet.
Also i love the instrument separation and soundstage. Mine is run off a normal 9v battery, but works fine, and can run the battery to lower voltage than the stock opamp i had.


----------



## ecohifi

Quote: 





ostewart said:


> my iPod has mainly 320kbps or apple lossless for the music i really like, some others are lower bit rate but havent listend to them yet.
> Also i love the instrument separation and soundstage. Mine is run off a normal 9v battery, but works fine, and can run the battery to lower voltage than the stock opamp i had.


 


 I think you're going to like the AD 823 more!!!  If you can solder SOIC devices to an adaptor definately give ADA 4627-1B version a try!
  I cant comment on the AD823 but the LME49720 is ahead of most BB apart from the OPA 827


----------



## genclaymore

Tried out LT1057 but I had the CN8 and not the ACN8 which is the better model of the Two, I didnt like the results when it was paired with the 2x LME 49720NA and 2x LME49710NA  with the LT1057CN8 in my Fiio E9. So I put the OP2107AP in it that i had earlier but I also changed the Buffers in my X-Fi HD to 2xLT1028ACN8 i Do like this combo, But I didnt try the same with the LT1057CN8 in my Fiio E9, The results should be better then it was with the 2x LME49710NA in my card bufers with the LT1028ACN8.


----------



## Ooztuncer

Hello,
   
  I am planning to replace opamps in my Onix XCD-88 cd player and I think I am in need of four OPA627 (AP or BP) and two BrownDog adapters; but have several questions in my mind:
   
  1. Is this the adapter: http://cimarrontechnology.com/single-to-dualop-ampadapter-dipversionpn021001.aspx OR do I need something else?
  2. What exactly is a DIP socket - should it be installed on the adapter (for additional $6 I believe in the above link)?
  3. Any recommendations on the opamp selection (other than the 627) for the Onix XCD-88?
   
  Sorry for my noob questions. Thanks in advance...


----------



## ecohifi

Quote: 





ooztuncer said:


> Hello,
> 
> I am planning to replace opamps in my Onix XCD-88 cd player and I think I am in need of four OPA627 (AP or BP) and two BrownDog adapters; but have several questions in my mind:
> 
> ...


 


 Dip socket is on http://cimarrontechnology.com/othercomponents.aspx, you are going to need 2 of these for this single to double adapter if you use OPA 627. 
  The OPA 627 are expensive and are typical BB sound and are warm.  Depending on what you are trying to acheive and what was in it originally it is hard to tell. 
  The OPA 827 is in my opinion a better and cheaper option but only comes in SOIC.  See http://cimarrontechnology.com/single-to-dualop-ampadapterpn020302.aspx
  If you want better then you haver to steer away from BB but these are safe and easy to install and operate without getting into stability issues!


----------



## Tommy Thong

Quote: 





ostewart said:


> LME 49720NA - just put it in my miu audio amp, it is very nice sounding, very natural, gives the sound more air and more space, bass goes deeper, but also makes it sound more musical. im really liking this opamp compared to the stock that came with the MIU amp. now awaiting my AD823, see what thats like.


 

  same as mine, that's why preferred to you, bro. I like lme49720na' sound too


----------



## Tommy Thong

i agreed to ecohifi too, try opa827 + adapter or if you don't want too much complicate, then try lme49720na

  
  Quote: 





ecohifi said:


> Dip socket is on http://cimarrontechnology.com/othercomponents.aspx, you are going to need 2 of these for this single to double adapter if you use OPA 627.
> The OPA 627 are expensive and are typical BB sound and are warm.  Depending on what you are trying to acheive and what was in it originally it is hard to tell.
> The OPA 827 is in my opinion a better and cheaper option but only comes in SOIC.  See http://cimarrontechnology.com/single-to-dualop-ampadapterpn020302.aspx
> If you want better then you haver to steer away from BB but these are safe and easy to install and operate without getting into stability issues!


----------



## Ooztuncer

Quote: 





ecohifi said:


> Dip socket is on http://cimarrontechnology.com/othercomponents.aspx, you are going to need 2 of these for this single to double adapter if you use OPA 627.
> The OPA 627 are expensive and are typical BB sound and are warm.  Depending on what you are trying to acheive and what was in it originally it is hard to tell.
> The OPA 827 is in my opinion a better and cheaper option but only comes in SOIC.  See http://cimarrontechnology.com/single-to-dualop-ampadapterpn020302.aspx
> If you want better then you haver to steer away from BB but these are safe and easy to install and operate without getting into stability issues!


 

 Thank you very much for the advice. I am little bit thick headed nowadays and have several more questions - clarification requests per say. If I go with the 2x OPA 627 (A-B-C-M whatever) selection, do I need to buy _*2 adapters and 4 dip sockets*_ - would you please confirm?  
   
  And for the second question, originally, XCD-88 (rebadged musichall cd-25) uses 2604s.
   
  The system I will be using this cd player is either (xcd88>>stello da100>>schiit lyr with GE 6BZ7 tubes>>lcd2 rev1) or (xcd88>>onix sp3 tube amp with various tubes>>strata mini or stone image audio rothschilde A2 speakers)[size=x-small]*.*[/size]  
   
  For both of the system, mainly I am looking for more detail and/or resolution (rather than making it _more_ musical or colorful); but I do not want to cannibalize the bass-mid response since they are great for my taste as is. I am also contemplating the idea of buying aftermarket cables since almost everything is in stock form (rather than changing the op amps).
   
  Thanks again.
  Cheers.


----------



## ecohifi

Quote: 





ooztuncer said:


> Thank you very much for the advice. I am little bit thick headed nowadays and have several more questions - clarification requests per say. If I go with the 2x OPA 627 (A-B-C-M whatever) selection, do I need to buy _*2 adapters and 4 dip sockets*_ - would you please confirm?
> 
> 
> For both of the system, mainly I am looking for more detail and/or resolution (rather than making it _more_ musical or colorful); but I do not want to cannibalize the bass-mid response since they are great for my taste as is. I am also contemplating the idea of buying aftermarket cables since almost everything is in stock form (rather than changing the op amps).


 
  Yes, you will need 2 adapters and 4 dip sockets if you go with the OPA 627 dip version.
   
  For detail/resolution the OPA 627 A series will not give you that and I didn't find them very resolving and detailed, initial inpressions and confirmation with other opamps i have tried.  Like you I tried the OPA 627 first because of the buzz people on other sites were giving it. 
  The OPA 827/1612/1642 series is far more resolving and like others on this thread try the LMEs. And when you are done with those move onto the ADIs.  Most BB apart from the 827 have a typical BB sound and the 627 is the most vealed out of the lot with good mids and powerful base and no resolution.
   
  Changing the opamps will give you huge change in SQ than changing a cable!


----------



## fzman

guess these would not be good opamps for a vegetarian!
  
  Quote: 





ecohifi said:


> Most BB apart from the 827 have a typical BB sound and the 627 is the most vealed out of the lot with good mids and powerful base and no resolution.


----------



## SpudHarris

Quote: 





> Originally Posted by *fzman* /img/forum/go_quote.gif
> 
> 
> guess these would not be good opamps for a vegetarian!


 

 Subtle but brilliant!


----------



## ecohifi

Quote: 





fzman said:


> guess these would not be good opamps for a vegetarian!


 

 Try valves???


----------



## SpudHarris

Quote: 





fzman said:


> guess these would not be good opamps for a vegetarian!


 

 Maybe they just do not meat with his expectations being as they are vealed?


----------



## ecohifi

Quote: 





spudharris said:


> Maybe they just do not meat with his expectations being as they are vealed?


 

 Like I said, maybe valves will meat the expectation!!!!


----------



## ostewart

very random posts there, made me laugh alot, i dont like vealed either, the do not meat my expectations, i prefer detailed


----------



## ecohifi

Quote: 





ostewart said:


> very random posts there, made me laugh alot, i dont like vealed either, the do not meat my expectations, i prefer detailed


 

 maybe valves will meat your expectation to resolve the details you need!!!!


----------



## SpudHarris

Still not sure he gets it though and I ham not going to explain it!


----------



## Tribbs

Warren Young describes the JFET Cascode as a constant current source in his article "Biasing Op-Amps into Class A".
   
  While searching around I stumbled across this very old thread which implies that BrownDog can make a JFET Cascode adapter.
  
  Does BrownDog or anyone else make a JFET Cascode current source opamp adapter?

 ___________________________________________________

I'm new around these parts and haven’t read this entire thread.
So, if this has already been discussed please excuse me.
Links to relevant threads, posts or sources would be very much appreciated.


----------



## ecohifi

send an email to Browndog adapters.  Biasing opamp into class A usually involves a resistor that is connected to the rail and output,  I have read threads that have done this.  I am not into it because most  data sheets of  opamps do not discuss this type of biasing.  Cant place emphasis on reliability!


----------



## SpudHarris




----------



## Tribbs

I am aware of the resistor method for constant current opamp biasing.  But it is not optimal and the better JFET Cascode method is certainly feasible.
   
  [...]
_There are two problems with a simple resistor current source. First, it will only give a constant current level while the op-amp's output signal remains constant. If the op-amp is amplifying a music signal, the bias level will only be constant during the silent parts, but the bias is there to improve the audible parts. This isn't to say that a resistor bias is useless, just that the bias level will vary with the output signal level, which is suboptimal._ [...]
   
_The second problem with this method is that the higher the op-amp's load impedance, the better the dynamic performance of the op-amp. That's one reason buffers help op-amps to perform better: they present an impedance in the megohms range to the op-amp. Using a resistor down in the kilohms range to bias the op-amp's output negates this benefit._
  [...]
   
  by Warren Young > *http://tangentsoft.net/audio/opamp-bias.html*


----------



## SpudHarris

Quote: 





tribbs said:


> I am aware of the resistor method for constant current opamp biasing.  But it is not optimal and a better method is certainly feasible.


 

 Please tell us what that is!
   
  I have tried the resistor method on many opamps and it's fair to say I dislike the results on quite a few. There are however a handfull where they sound considerably better.


----------



## Tribbs

Quote:


spudharris said:


> Please tell us what that is!


 

      *I ALREADY DID...*
   
       Quote:


tribbs said:


> Warren Young describes the JFET Cascode as a constant current source in his article "Biasing Op-Amps into Class A".


----------



## Tribbs

Quote:


ecohifi said:


> send an email to Browndog adapters.


 

 Done!
   
  I am hoping BrownDog can build JFET Cascodes on an opamp adapter for a reasonable price.  I'm wildly guessing about $20/ea.  It may come down to a group buy to make it feasible.
   
*How about a show of hands by those who are willing to purchase...*


----------



## ecohifi

Quote: 





tribbs said:


> Quote:
> 
> Done!
> 
> ...


 

 Trbbs,
   
  if you search hard enough you will find a site that actually sell these, I think it was a chinese site,  Placing a resistor from a rail to the output forces the feedback to correct the output voltage will turn one side of the opamp on, hence class A biasing on that side.  There are a lot of sites that discussed this but there are no references on any data sheet to accredit this.  Remember the idea is to run them to stay within operating temperature.  Dont forget that opamp rolling also have an affect on stability if the circuit doesn't support it, again check the data sheet.
  If BB ADI and LME designers thought that the biasing for the op amp was not enough than they would have cater for it, Look at the specs on the data sheets and check the distortion figures!
  Also check the bias current on the AD 4627-1 and OPA 1141 they are in the pA!
  If you have spare browndog adapters like I have, you can place these resistors on the adapter yourself with some soldering skills
  
  Sorry mate, im out I need these to run reliable!!  Some ADI and LME chips run hot anyway and hotter when in use!  This practice would just increase heat levels.
   
  Good luck with it!!!


----------



## Tribbs

I am fully aware of how to class A bias an opamp using resistors.  Nevertheless, I appreciate your comments, Ecohifi.  I think I'll try prototyping a JFET Cascode.  It looks simple enough.
   
  FYI:
   
_"Shoving a current source on the output of a class AB push pull output opamp shuts off one of the transistor pair creating a class A single ended output up to around +6 dbu in output. This can be done with any opamp as only a simple "pull down" resistor from the output pin to the - rail does it. 7.5k ohms at +-15 v supplies gives 2 ma. More modern higher current opamps need a bit more, around 3~4 ma."_ (< Click to reveal source.)
   
  By definition if the output stage of opamps is biased to class A, the half of the complementary output (transister) pair that is biased ON is always ON and conducting (faster NPN transistors) while the device that is biased OFF is always OFF (PNP transistors).  Therfore, there is no crossover distortion.
   
"_A simple resistor load, while electronically simple and fool-proof, has the least steady current loading, as it's loading varies anytime the supply voltage varies. A FET based current load will have a much steadier current under varying conditions, and therefore work and sound better_." (< Click to reveal source.)
   
  The entire point of this discussion is that using only resistors is an inferior method of class A biasing an opamp.
  As Warren Young has clearly exlained here > *http://tangentsoft.net/audio/opamp-bias.html ,*
and from which I have quoted in my previous post, employing a JFET Cascode circuit is superior to resistors.
   
If you know of anyone that sells [size=x-small]a *JFET Cascode *OpAmp adapter utilizing JFET transistors, Q1 and Q2, (not resistors) as show in the following schematic,[/size]
   
[size=x-small]
	

	
	
		
		

		
			



[/size]
   
[size=x-small]please post their links![/size]


----------



## SpudHarris

Man you are rude..... Yeah we know you can quote we've seen it buddy, over and over. What we haven't seen is any positive input or detail about your own specific applications. Anyone can keep quoting stuff from Tangents Article and I suspect most visiting this thread have read it anyways. If you want help? you got a funny way about getting it. Welcome to my blocked member list!


----------



## murrays

These are fairly easy to solder up without a circuitboard, as the result is a 2-terminal "device" (this being the DIY forum).
  I have done them that way in the past: the 1 JFET + 1 resistor configuration, not for class-A, but for input offset biasing.
  There are also commercial "constant current diodes" available which are the same thing packaged up in a standard diode package.
  They are manufactured with a range of preset current specifications, so you have to do the maths first, to determine the optimal bias.
  With one of those it would be physically the same as using a resistor.


----------



## ecohifi

Quote: 





murrays said:


> These are fairly easy to solder up without a circuitboard, as the result is a 2-terminal "device" (this being the DIY forum).
> I have done them that way in the past: the 1 JFET + 1 resistor configuration, not for class-A, but for input offset biasing.
> There are also commercial "constant current diodes" available which are the same thing packaged up in a standard diode package.
> They are manufactured with a range of preset current specifications, so you have to do the maths first, to determine the optimal bias.
> With one of those it would be physically the same as using a resistor.


 
  +1 agreed!
  Murrays,
   
  to give Tribbs and me some feedback, how did you find them?  Was there an improvement and was it worthwhile?  And were there drawbacks on heat and reliabilty?  If you dont mine me asking!!
   
  Tribbs,
   
  you can try this with a breadboard.  I haven't thought about that route, but by all means give it a go! 
   
   
  SpudHarris,
   
  please accept my apologies if I have upset you, I have no intentions of upseting anyone with my posts, just having fun and knowledge sharing is my game.  Cant live without everyones input!


----------



## murrays

Quote: 





ecohifi said:


> +1 agreed!
> Murrays,
> 
> to give Tribbs and me some feedback, how did you find them?  Was there an improvement and was it worthwhile?  And were there drawbacks on heat and reliabilty?  If you dont mine me asking!!


 
   
  I made my DIY current sources for a different purpose. My bipolar input chip had a lot of offset and was fully direct-coupled (no caps) so I needed to apply a slight current bias on the inputs to balance the outputs.  On the input a much lower bias was required (nanoamps rather than milliamps) so the resistor values were many megohms and extra heat is not an issue.  The resistors had to be individually selected to achieve the correct current (one channel need +ve, the other needed -ve).
   
  As far as output biasing goes, my DAC is an Adcom GDA-700 which uses class-A biasing of all the opamps as part of the design.  It has a great sound but I haven't tried removing them to see the difference.  Adcom used class-A biasing on their opamps in the 1990's.  However the chips they used (AD711/AD712) had been determined to benefit from it (I think there is a Walt Jung article on it).  They commonly used the J555 2mA device.  Many modern chips have improved output stages that do not benefit so much from the class-A biasing practice.  It may even make things worse.  Experience from others and experimentation will be required.
   
  Extra current will always generate more heat.  Some maths (Ohms law) is required.  If you can't hold your fingertip on a chip because of its temperature, then it is too hot.


----------



## ecohifi

>


 

 Thanks Murrays.
   
  Tribbs,
   
  these articles are referring to transistor input devices and one is dated back 2001,  Try some current Fet input opamps such as AD 825, ADA 4627-1 OPA 827 and OPA 1611 if you have not already done so.  Have a look at there bias currents in the data sheet and compare them to a transistor input opamp such as LMEs.


----------



## Mad Max

Quote: 





spudharris said:


>


 

 How are you finding 1678/1677?


----------



## SpudHarris

Quote: 





ecohifi said:


> SpudHarris,
> 
> please accept my apologies if I have upset you, I have no intentions of upseting anyone with my posts, just having fun and knowledge sharing is my game.  Cant live without everyones input!


 

 No, echohifi we are cool I was not addressing that post to you. You seem like a real nice guy. It was addressed to Tribbs who seems very rude considering he was asking for advice.


----------



## SpudHarris

Quote: 





mad max said:


> How are you finding 1678/1677?


 


 Well I love the 1678. They are my new best friend haha.
   
  Ron (hiflight) tells me that the 1677 is a different chip. I haven't looked at the specs but I'm told the slew rates amonst other things are not the same. I have had the 1677's for ages and have to say I never really wanted to keep listening to them whereas the 1678's are now in my P4, PB2, Fi-Quest and EF5. They all sound fantastic.


----------



## Mad Max

Ah my bad.  I did not like 1677.  1678 has pretty low slew rate.


----------



## ecohifi

Quote: 





spudharris said:


> No, echohifi we are cool I was not addressing that post to you. You seem like a real nice guy. It was addressed to Tribbs who seems very rude considering he was asking for advice.


 
  Thanks SpudHarris, its all cool and I'm flattered,  I need you to keep me in check with my spelling errors LOL, FYI I failed English.  Maybe it was my fault because I dont think I read Tribbs post correctly!
   
  Ladies and guys,
   
  FYI,  there is an electronics magazine called Silicon Chip in Aust that have published a head amp kit and a pre amp that uses a LM833.  Interestingly they believe that they can achieve a lower distortion figure than the current LME 49720 or LME 49990.  There previous pre amp published in 2005 was based on an OPA 2132/4, this is what I am using to evaluate these 8 legged devices.  Cant post the article here due to copyright, but I have heavily modified it to make it sound better than my full discrete bipolar preamp!  Well to my old ears  I believe it sounds better,
   
  While you guys are on the 1677/ 1678 have you two tried the 1122 while we are on the LTs?


----------



## SpudHarris

Quote: 





ecohifi said:


> Thanks SpudHarris, its all cool and I'm flattered,  I need you to keep me in check with my spelling errors LOL, FYI I failed English.  Maybe it was my fault because I dont think I read Tribbs post correctly!
> 
> Ladies and guys,
> 
> ...


 

 Sounds cool. I like the LME49990 a lot. As with the LT1678 I bought enough to evaluate in my favourite amps and still swap this back into the EF5 now and again as it really shines with my LCD2.
   
  I'm sure I have LT1122's in my box. I will have to look and report back. Do you like them?


----------



## Tribbs

Quote:


> Originally Posted by *murrays* /img/forum/go_quote.gif
> 
> There are also commercial "constant current diodes" available which are the same thing packaged up in a standard diode package.
> They are manufactured with a range of preset current specifications, so you have to do the maths first, to determine the optimal bias.
> With one of those it would be physically the same as using a resistor.


 

 Constant Curent Diodes or Current-Regulating Diodes (CRDs) introduce a fairly large input capacitance into the signal path.
  Yes, they will work but at the expense of the audio.  You would want to avoid adding capacitance into the signal path at all costs.
  Again, Warren Young states this in his article. Hence the JFET Cascode.
   
  Quote:


> Originally Posted by *murrays* /img/forum/go_quote.gif
> 
> I have done them that way in the past: the 1 JFET + 1 resistor configuration


 
   
  Yup! You made a discret constant current diode.
   
  Quote: 





> Originally Posted by *ecohifi* /img/forum/go_quote.gif
> 
> Tribbs,
> 
> you can try this with a breadboard. I haven't thought about that route, but by all means give it a go!


 
   
  I have it on my list!  I'll try it out and report back when I have the opportunity.
   
  Thank's for everyone's feedback.  Including you SpudHarris 
	

	
	
		
		

		
			





  [Don't try to read between the lines.]


----------



## ecohifi

Haven't tried the 1677/78 but the 1122 is nice and dark and the highs are real and complete, I find the 1122 the best out of the LT range because I just really like FET input stages,  I still think the ADA 4627-1 b are hard to beat that is why I invested heavily into them.  I dont have a LCD 2 but a Stax Lamba.  The ADA 4627-1 really shows how its supposed to be done in both the stax and my main rig.  In a EE minmax plus it elevates the soundstage and completes the SQ,  Funny enough when both AD 825 and ADA 4627-1a arrived at the same time I didn't like the 4627, probably because the AD 825 was'nt so detailed and heavy in the bottom end but had this airy transparency that I was craving for that didn't exist on the OPAs.  I had the AD 825 at least 7mths when I decided to swop.  When I fitted the 4627 and cranked up the volume, I realised I misjudge them.  The 4627 was like a AD 825 with guts not to mentioned the  detailed bottom end had returned with balls.


----------



## SpudHarris

I prefered the ADA4637BRZ over the 4627. They are both nice but I guess it's personal preference and application, the 4637 are really nice in my balanced PB2....
   
  I haven't got the LT1122 as I thought, I have the LT1124 but I haven't listened to it for ages so can't really comment on it. Of the LT chips I do like the 1363 and 1468. The 1363 are very, very nice and you must try them if you haven't.


----------



## SpudHarris

Can you tell me more about LT1122?
   
  I have 4 off in my Farnell shopping basket but wondered how they compare to others like OPA4627/37 / 1611 / 1641 / 602 / LT1678 / LME49990 (all favorites)
   
  Cheers


----------



## ecohifi

I like the OPA 1611/ 1612 / 827 better than the LT 1122.  Probably not worth trying and I love the ADA 4627-1 A & B versions
  If you get a hold of the LT site you can order these as samples like I did, No cost delivered under research!  Same deal with the Texas Instruments you can get the OPA 1611/1612/827 as samples!
   
  With the LTs there are also the 1115,1028 but the 1122 is the better one!  The LT1122 is a new process of manufacturing, just like the OPA 1611/ 1641 / 827.
   
  The ADA 4627/4327 is supposed to be the answer for the OPA 627/637,  I have not tried the 4327 or the 637 because they are supposed to support gain of 5>


----------



## Mad Max

I did like 1115 a bit better than 1028, so 1122 is even better?  Might as well order samples and see.  =P
   
  I find OPA602, 827, AD797, and 4627 all equally detailed, but 4627 brings on the details with a bit more clarity than the others.  Its treble clarity is also the best.  All four give my M-Stage deeper bass than stock which is a big help for Grados and K701.  They no longer leave out some of that really low frequency ambiance and effects in electronic music.


----------



## ecohifi

Mad Max,
   
  thats my opinion according to my ears and the circuit its in.  The LT1122 has good slew rate and is unity gain stable.  But if you have the ADA 4627-1 I dont think its worth trying, then again just do it out of curiousity!


----------



## DefQon

Anyone here has experience with the AD8599?


----------



## Mad Max

I haven't tinkered with 8599, but I have 8597, the single version, and it is a very good chip, but a little too forward in the bass.  I haven't tried it with bypass caps, which I need to.  ADI recommends 8597 and 4627 instead when you look at the AD797 page.


----------



## ecohifi

Hi guys,
   
  I stuffed up, I've given you guys some misleading info on my part and would like to apologised for it.
   
  On that LT list I quoted 1115, I haven't used the 1115 and shouldn't comment on it, it was on a to do list that I had mistaken for that was done!
   
  The list for the LTs that I have tried should be: 1028, 1122 and 1364.
   
  Please accept my apologies!!!!!
   
  I am thinking of trying an ADA 4989-2, if someone has had experience with this one I could used the feedback!!!


----------



## Mad Max

Do you mean ADA4898?  It is a favorite.  I forgot to connect the exposed pad underneath to pin 4 (or add a wire to connect the pad to ground somewhere), so I'll have to build another module, lol.  Fantastic midrange, but lacks the bass, treble, and soundstaging of 4627.


----------



## ecohifi

Quote: 





mad max said:


> Do you mean ADA4898?  It is a favorite.  I forgot to connect the exposed pad underneath to pin 4 (or add a wire to connect the pad to ground somewhere), so I'll have to build another module, lol.  Fantastic midrange, but lacks the bass, treble, and soundstaging of 4627.


 
  Yes the ADA 4898, there is a ADA4898-2,  Thanks for the feedback I give it a miss if thats the case


----------



## Mad Max

I think it is worth a try if you are bored, lol.


----------



## ostewart

i just got a AD823AN opamp, and im not as pleased as when i got my LME49720NA, but it has better bass than the LME, the soundstage and detail, and air, just isnt there like with the LME.
Will give it some time, then see which i like better.


----------



## Lavcat

Quote: 





tribbs said:


> Warren Young describes the JFET Cascode as a constant current source in his article "Biasing Op-Amps into Class A".
> 
> While searching around I stumbled across this very old thread which implies that BrownDog can make a JFET Cascode adapter.
> 
> ...


 


 I used a standard BrownDog adapter and two Central Semiconductor 1N5314 CRD's to bias a pair of OPA627's into class A with good results.  There is space to mount the 1N5314 diodes between the DIP socket pins if you're careful.


----------



## stupid11

excuse me, can I have a recommendation on dual or 2Xsingle op amp with rounded bass warm mids and smooth treble as well as good treble extensions???
   
  i am currently using 12V Cmoy with OPA627AUX2 bias and LM6171 on ground. but still find problem with sibilance mids and bad treble smoothness and extension
   
   
  how about LM4562HA metal???


----------



## civilaudio

Quote: 





spudharris said:


>


 


  hi Spud,
  I saw you are using 2 resistors of 2.2k for each dual adapter  ... Is the value of resistors must be fixed to that value? What is the best value for this?
  thanks


----------



## SpudHarris

Hmmmm. Well many will tell you that it should vary dependant on the opamp. I took this value because it is what was recommended by the opamp guru that is ''Hiflight''. I'm lead to believe that this is as _*close as you will get *_to a one size fits all.....


----------



## civilaudio

Quote: 





spudharris said:


> Hmmmm. Well many will tell you that it should vary dependant on the opamp. I took this value because it is what was recommended by the opamp guru that is ''Hiflight''. I'm lead to believe that this is as _*close as you will get *_to a one size fits all.....


 


  ahh.. thanks, I went to local shop and somehow bought the 2k resistors (instead of 2.2k) and tried to copied Topkit adapter... mine is kind of funny (i.e. no photo) as I choose to put the resistor outside of the adapter (so the pin of adapter can go deeper in the slot)...
   
  and as you said 2.2k is almost the best the 2k should not be that far...


----------



## SpudHarris

I've bought some smaller resistors since that allow the socket to go deeper. 2k should be fine, what opamp are you using it with?


----------



## qusp

Quote: 





spudharris said:


> I've bought some smaller resistors since that allow the socket to go deeper. 2k should be fine, what opamp are you using it with?


 


  I wonder why i never see anyone using surface mount LEDs for the CCS bias? much lower noise


----------



## Mad Max

Cuz they don't know that?
   
  Now I do.  =p


----------



## civilaudio

Quote: 





spudharris said:


> I've bought some smaller resistors since that allow the socket to go deeper. 2k should be fine, what opamp are you using it with?


 


  oh...the LT1355 (special favor from Hiflight), it stayed in my D12 now with EL8201. I also just got the 8620 from browndog.. and tried to test with class A.


----------



## qusp

Quote: 





mad max said:


> Cuz they don't know that?
> 
> Now I do.  =p


 


  =D well you see LEDs being employed in solid state amps and the odd tube amp or power supply/regulator as part of a low noise current source or voltage reference for bias all the time, i just wondered why i'd never seen it used with opamps here. they arent the most stable reference available due to changing their forward voltage drop with temp, but then so do resistors and LEDS are lower noise..and so pretty


----------



## kiteki

Hi I just bought these on ebay yesterday:
   

   
http://www.ebay.com.au/itm/130579789470
   
   
  100% feedback so it should be the real deal.


----------



## kiteki

I'm also curious about these:
   

   
   
  Anyone have any thoughts or know where I can buy them?


----------



## civilaudio

Quote: 





kiteki said:


> I'm also curious about these:
> 
> 
> 
> ...


 

 I think digikey has these muses... I am really curious about these also, wondering why they can charge too high.


----------



## Tribbs

Quote: 





civilaudio said:


> I think digikey has these muses... I am really curious about these also, wondering why they can charge too high.


 
   
http://search.digikey.com/us/en/cat/integrated-circuits-ics/linear-amplifiers-instrumentation-op-amps-buffer-amps/2556125?k=MUSES
   
http://semicon.njr.co.jp/eng/MUSES/MUSES01.html


----------



## ecohifi

Quote: 





tribbs said:


> http://search.digikey.com/us/en/cat/integrated-circuits-ics/linear-amplifiers-instrumentation-op-amps-buffer-amps/2556125?k=MUSES
> 
> http://semicon.njr.co.jp/eng/MUSES/MUSES01.html


 

 Its called monopoly!!!!


----------



## qusp

Quote: 





civilaudio said:


> I think digikey has these muses... I am really curious about these also, wondering why they can charge too high.


 


  the way i see it, not all that much reason. specs are pretty ordinary (not even good) in a number of categories by todays standards, seems everyone else agrees because its becoming a non-stock item when/if they can sell the rest of the parts. it looks to me like they are still selling the initial stock purchase from 2009 and maybe i'm living in a ditch but ive never heard of them
   
   
   
  'pursuing super low crosstalk between left and right channels' 
   
  lol, then make a single


----------



## kiteki

$50 for a single opamp + shipping.
   
   
  I'll pass.


----------



## Mad Max

$50 is more than enough for killer opamps.


----------



## kiteki

What's a killer opamp to replace the NE5532 with?


----------



## G.Trenchev

OPA1612 ?


----------



## subballo

I have a HA INFO NG94 version 1 dac and would like to try different opamps in it. Opamps in it are rollable so the change probably should be pretty easy. It has two opa2604 at the I/V section (whatever that is) and one opa2604 for the output buffer. I assume that these are for the dac. Then it has two BUF634's and one opa2604 for the headphone amplifier. So does anyone have any tips which opamps would work fine in this configuration? I don't have any electronics skills so I can't do anything else than change the opamps.


----------



## Mad Max

No need to change the BUF634.  Replace the 2604 in the headamp with a pair of OPA602B; you will need an adapter for it.


----------



## AudioHeadHZ

Hi,

I want to know if someone already know this online store: http://components.arrow.com/, and, if yes, if it's a reliable and/or recommended one; or if you have some suggestions on where i can buy 3 AD797ANZ op-amps (for the xonar essence).

Thanks


----------



## ecohifi

Quote: 





audioheadhz said:


> Hi,
> I want to know if someone already know this online store: http://components.arrow.com/, and, if yes, if it's a reliable and/or recommended one; or if you have some suggestions on where i can buy 3 AD797ANZ op-amps (for the xonar essence).
> Thanks


 


 Depends on the region your're in!!!


----------



## Mad Max

Arrow is good, but total price will depend on your region.


----------



## AudioHeadHZ

Indeed, since i'm in Europe, the cost it's surely less affordable...

But i've found only this reseller http://www.display.nl/ic-op-amp-uln-dil-8-ad797anz (actually i'm in Belgium), and i don't know if is a good and/or recommended one. Else, did you have recommendations on a good store around here?


----------



## subballo

Quote: 





mad max said:


> No need to change the BUF634.  Replace the 2604 in the headamp with a pair of OPA602B; you will need an adapter for it.


 


  Thanks for the tips. I put an order for pair of OPA602B's and an adapter. I also send a payment for you for the OPA827's but I can't reply to that private message because of my daily allotment of 2 private messages per day.


----------



## ecohifi

Quote: 





audioheadhz said:


> Indeed, since i'm in Europe, the cost it's surely less affordable...
> But i've found only this reseller http://www.display.nl/ic-op-amp-uln-dil-8-ad797anz (actually i'm in Belgium), and i don't know if is a good and/or recommended one. Else, did you have recommendations on a good store around here?


 


 Try element 14,  downunder they are fairly competitve and are willing to negotiate a price.  The other is Digikey.


----------



## ecclesand

Where are you all buying your S08 to DIP8 adapters?  I had a source on Ebay but he hasn't had them in a while.  I have bought from Cimarron but they're expensive and I've had some bad luck recently with a couple of their dual S08 to DIP8 adapters.


----------



## SpudHarris

Bought these last time and they are great quality...


----------



## ecclesand

Quote: 





spudharris said:


> Bought these last time and they are great quality...


 


  I tried some of those a long time ago but found them difficult to work with.  My soldering skills have improved since then so maybe I should give them another try...I think I still have a few of them.
   
  Thanks, Nigel!


----------



## Mad Max

I've been using diyinhk's adapters for the past couple of years.  (Spudharris' link)
  But I've used their 2x1 adapters.  For only one soic chip at a time, I go with iBasso's.
  They're badass.


----------



## SpudHarris

Agreed, they are quality. I have a few of those also. My only issue with them is they can be a little difficult to get out of the socket once in as they sit real flush so their is nothing to grab hold of. On occasions I've had to try an lever them out but putting something underneath.


----------



## Mad Max

I use these if I have issues.  I bought one for a fraction of the price a long time ago.
  I use iBasso's mainly for my portable amp as it takes singles only.  I did use one for OPA1602 to try out in one of my DACs.


----------



## ecohifi

Hi Guys,
   
  Looks like I'm the dummy here, I have been relying on Cimarron all this time, do the other sites contain a dual soic to single DIP like what browndog have?


----------



## Mad Max

link
link, which also needs the pins
link, which also needs the pins
link
link
   
  There's probably more out there.
   
  Knock yourself out.  =D


----------



## ecohifi

Quote: 





mad max said:


> link
> link, which also needs the pins
> link, which also needs the pins
> link
> ...


 


 Thanks Mad Max!!


----------



## kiteki

Which opamps have a colourful sound full of life, haze, and jest?
   
   
  As opposed to the famous accuracy ones, (I love NE5532 from what I can tell though).


----------



## Willakan

Not many. Opamps are, prettymuch without exception, designed to objective criteria with lots of very expensive instrumentation.


----------



## fzman

ad797 is a single opamp - the stx uses duals - you would need 6 797s and adaptors to go from 2 singles to one dual x 3!!!!  be careful or you can damage your card if you socket 797s into the card as-is!!!!


----------



## PurpleAngel

I'm thinking of getting a OPA2107AP (DIP-8) for the buffer on my Essence STX, currently using 3 X LME49860NAs.
  The ones sold in the USA sell for $16
  The ones sold and shipped from China go for $4-$5.
  Makes me think the ones from China are fake?


----------



## Mad Max

That or they are used but advertised as new.  They can also be new old stock.


----------



## PurpleAngel

Quote: 





mad max said:


> That or they are used but advertised as new.  They can also be new old stock.


 
  Used, like they were cut off some old PCB board?


----------



## Mad Max

Desoldered from some older electronics, I guess.


----------



## PurpleAngel

Any known differences between the AD797AN & AD797BN?
  And what places in the USA has the best prices on them?
  Not sure I would trust any shipped from China.


----------



## Mad Max

Digikey.


----------



## Tribbs

Difference between AD797AN & AD797BN?  About $2 
	

	
	
		
		

		
			




   
  Quote:


mad max said:


> Digikey.


 

  Also, Analog Devices pdf - see chart beginning on page 3.


----------



## PurpleAngel

Brain freeze help.
   
  I'd assumed AD797"N" are dual channel?
   
  I see SOIC AD797 mounted on SOIC to DIP-8 adapters.
  They put one AD797"R" on top and one on the bottom of the adapter.
  Are the "R" mono or dual channel ICs
  or do the AD797"R" come in both dual channel and mono channel?


----------



## Mad Max

There are only mono 797's.  To replace a dual opamp, you need two of them.


----------



## jcx

no warnings to the newbe that AD797 is not strictly speaking "unity gain stable"??
   
  not exactly helpful - the chip needs extra external components to be stable at low gains - can't be "dropped in" to most op amp circuits, even with adapter
   
  some here might benefit form this thread:
   
http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html
   
  I may not share the belief system that op amp rolling is a great idea but I don't see an excuse to set people up to fail by not giving them necessary engineering information


----------



## Mad Max

Quote: 





jcx said:


> no warnings to the newbe that AD797 is not strictly speaking "unity gain stable"??
> 
> not exactly helpful - the chip needs extra external components to be stable at low gains - can't be "dropped in" to most op amp circuits, even with adapter
> 
> ...


 

 Meh, lot's of people do it anyway.


----------



## ecohifi

Quote: 





jcx said:


> no warnings to the newbe that AD797 is not strictly speaking "unity gain stable"??
> 
> not exactly helpful - the chip needs extra external components to be stable at low gains - can't be "dropped in" to most op amp circuits, even with adapter
> 
> ...


 
  Jcx,
   
  good point, in the unity gain experimental pre I have, the AD 797 do not work!!!  In this unity gain circuit I have strickly used unity gain opamps and even some begin to sound thin and decided to distort.  An example is the LME 49990 that requires proper psu decoupling caps.  Another is the limited voltage supply requirements.  I had the AD 8066 in mind but thats limited to +-12V.  The circuit I am using has a +/-15V. 
  Without a scope it is hard to tell, some say that when an opamp oscillate the temp increases and becomes hot to touch.  I have noticed that some opamps are inherently hot anyway thats why a scope is required.  I use to have access to one but not any more.
   
  It is also good practice to google the device data sheet and download it and decide whether the device will suit your circuit.  The other tip is to find a device that is similar in requirements to the device you plan to replace or roll.


----------



## Mad Max

Yes, opamps do become too hot to the touch when they are oscillating.  They're supposed to be lukewarm, even with 30V across the power pins as far as I know (excluding things like class-A biasing and what not).
   
  Most people would be confused by your post and jcx's and know absolutely nothing about opamps other than that socketed ones can be swapped out with others.  How would you help them?  They seem to just want to go with whatever others are raving about.  For example, people are rolling LME49720 into the M-Stage and raving about the sound, but one head-fier has found that it is not suited for that particular circuit at all to begin with:
   
  Quote:  thread


> ... LME has offest that goes up within volume band raises slowly with gain (8mV to 18mV). This means that LME does not like changes in input resistance and needs steady resistance, OR FEEDBACK (that LC [or M-Stage] does not have). Furthermore, AD797 (the best, the fastest, etc...) opamp starts with 10mV and in high gain has huge amount of DC offset (100mV and more) which means that is not good for this kind of setup, at all...


 
   
   
  There's guides to equalizing your headphones around here but none on general opamp-rolling.  There's the occasional thread for a specific component, and mostly people's impressions from "blind-rolling" at that.  We should probably put together a concise thread for others to read and help reduce "setting up people to fail".


----------



## SpudHarris

Quote: 





mad max said:


> Yes, opamps do become too hot to the touch when they are oscillating.  They're supposed to be lukewarm, even with 30V across the power pins as far as I know (excluding things like class-A biasing and what not).
> 
> Most people would be confused by your post and jcx's and know absolutely nothing about opamps other than that socketed ones can be swapped out with others.  How would you help them?  They seem to just want to go with whatever others are raving about.  For example, people are rolling LME49720 into the M-Stage and raving about the sound, but one head-fier has found that it is not suited for that particular circuit at all to begin with:
> 
> There's guides to equalizing your headphones around here but none on general opamp-rolling.  There's the occasional thread for a specific component, and mostly people's impressions from "blind-rolling" at that.  We should probably put together a concise thread for others to read and help reduce "setting up people to fail".


 

 Nicely said and thanks!
   
  I'm one of the guilty ones blind (ishly) rolling as I do not know how to work through an opamp data sheet. i.e. whats good, whats bad, what will work, what may cause issues etc...etc... I've picked up a few tweaks here and there and can probably ''talk a good shag'' but I'd really value a more concise guide.


----------



## tomb

Quote: 





mad max said:


> There's guides to equalizing your headphones around here but none on general opamp-rolling.  There's the occasional thread for a specific component, and mostly people's impressions from "blind-rolling" at that.  We should probably put together a concise thread for others to read and help reduce "setting up people to fail".


 

 This has been done - and it was at least 6 years ago, maybe longer.  There have been a few other opamps created that might belong in this list, but not many.  Nevertheless, it gives numerous good pointers about what to select, how to employ them, and what you might expect in terms of sound differences.  This thread is so long, I'm sure it's been posted before, but it's probably a good idea to do it again:
   
Tangent's Notes on Audio Op-Amps


----------



## genclaymore

I been trying a-lot of different op-amp combos, I liked most of them, Others I didn't. I had to stop my self because I kept wanting to try another combo.   Right now I trying out 2x LME49860NA In the I/V , 2x LT1028ACN8's in the buffer of my X-Fi HD, With OPA2107AP in the Headphone Buffer socket in my Fiio E9.  I liking this combo so far, I had a OPA2111AM in my Fiio E9, but with the 2x 1028ACN8, the bass was punchy and the bass was uncontrolled.  But with 2xLME49710NA in the X-Fi HD buffer with the OPA2111AM in the Fiio E9, its bass sound good to me.
   
  Planning on getting a Matrix M-Stage, its more roomy inside so I can use my dual to single op-amp adapter  as well as being able to access it insides much much easier. While being able to see what I doing.
   
  With the Fiio E9, I have to put a small flash light in my mouth angled into the front opening, while I pull up the op-amp with one of those small pointy tools with a  grooved hook, I cant think of their name. Since the motherboard bios chip puller I have isn't angled. While holding the Fiio E9 steady in my hand. When you swap op-amp a-lot, it makes you wish the amp was in a bigger casing and easier to access.


----------



## Mad Max

Quote: 





tomb said:


> This has been done - and it was at least 6 years ago, maybe longer.  There have been a few other opamps created that might belong in this list, but not many.  Nevertheless, it gives numerous good pointers about what to select, how to employ them, and what you might expect in terms of sound differences.  This thread is so long, I'm sure it's been posted before, but it's probably a good idea to do it again:
> 
> Tangent's Notes on Audio Op-Amps


 
   
  While I've seen that page before, it is hardly linked or mentioned outside of the DIY forum within Head-fi.  We should come up with something like "An Idiot's Guide to Opamp-rolling".  That link should be part of the guide or at least have mention of that page, along with this one, this one, and others, maybe link to some of the threads that I've seen on diyaudio.com.
   
  I'm not quite sure how to fully express what I'm thinking.


----------



## tomb

Quote: 





mad max said:


> While I've seen that page before, it is hardly linked or mentioned outside of the DIY forum within Head-fi.  We should come up with something like "An Idiot's Guide to Opamp-rolling".  That link should be part of the guide or at least have mention of that page, along with this one, this one, and others, maybe link to some of the threads that I've seen on diyaudio.com.
> 
> I'm not quite sure how to fully express what I'm thinking.


 

 Then maybe you should do it?


----------



## genclaymore

I put the LME 49720NAs and LME49710NA back into my sound card. Went back to rolling the op-amps just in my fiio E9 instead of both sound card and amp. I like the mid range and mid bass of the LT1057CN8 On my DT880 pro-250. The way It makes the mids sound fuller or more of it. I cant explain it.  Tho when I first Tried the LT1057CN8, I tried it with the AKG 702s I had before these headphones, didn't like it with those.  While with the AKG 702s I liked the LT1057ACN8s, Where the same LT1057ACN8s i didn't like with these DT880 pro250.
   
  Now i can stop rolling op-amps for a while Til I get this new amp that I saving for.


----------



## SpudHarris

Yeah, I'm afraid it get's ya like that....
   
  Some days everything sounds sweet and other days I yearn for a little bit more or something a little different (depending on what I'm listening to). It's a very specific type of OCD I'm afraid and if you are visiting this thread? I'm afraid there ia a good chance you may be suffering the same affliction, so sad 
	

	
	
		
		

		
			





 but true....


----------



## leeperry

spudharris said:


> Yeah, I'm afraid it get's ya like that....
> 
> Some days everything sounds sweet and other days I yearn for a little bit more or something a little different (depending on what I'm listening to). It's a very specific type of OCD I'm afraid and if you are visiting this thread? I'm afraid there ia a good chance you may be suffering the same affliction, so sad
> 
> ...


 

 Sadly, I think that's because opamps will never match discrete designs...there's a long thread on diyaudio on that matter: http://www.diyaudio.com/forums/everything-else/88894-discrete-components-better-than-opamps.html
   
  And I'm not talking about discrete DAC's based on a voltage output DAC chip(that has a crappy I/V stage embedded) or cheapo discrete opamps, I'm talking about fully discrete designs. Opamps are just a cheap shortcut I'm afraid...and dual opamps are even worse than singles.
   
_"to me a well-designed discrete circuit sounds better, and i've rolled a lot of op amps. they all sound different from each other, so i couldn't imagine how they don't degrade the sound. to me the difference between various op amps even within the same manufacterer is like night and day. people with half-decent ears (like myself) should do a blind test comparing a cascade of op amps to straight wire. that will effectively demonstrate that op amps suck."_
   
  Amen


----------



## genclaymore

I even thinking about grabing a Audio-GD NFB - 12 and calling it a day. Other then it being more affordable over the Matrix M-stage. So I can stop doing all of this op-amp rolling madness, that I cant stop from doing.


----------



## leeperry

I've opened a thread on that matter: http://www.head-fi.org/t/588070/opamps-thd-n-imd-snr-measurements-dont-mean-jack-irl-so-let-it-go-hummkay


----------



## DefQon

Anyone know a good cheap source for the AD8599 and AD744? My previous luck was on fleabay where the AD8588/AD744 were only $8 shipped, now there is only 2 sources that has the AD8599/AD744 for almost $20.


----------



## ROBSCIX

Quote: 





genclaymore said:


> I even thinking about grabing a Audio-GD NFB - 12 and calling it a day. Other then it being more affordable over the Matrix M-stage. So I can stop doing all of this op-amp rolling madness, that I cant stop from doing.


 


  Opamp rolling is just a sign of wanting to get more out of what you have..IMO.  If you move to a device without opamps for instance, you will just find something else to change and mod.  To me the quest for better audio is a part of the fun.  Trying to tweak, tune and choke more sound quality out of the devices I have.  You can go with a new device, but it might not stop you from tweaking..just from changing opamps in that device.


----------



## SpudHarris

Quote: 





robscix said:


> Opamp rolling is just a sign of wanting to get more out of what you have..IMO.  If you move to a device without opamps for instance, you will just find something else to change and mod.  To me the quest for better audio is a part of the fun.  Trying to tweak, tune and choke more sound quality out of the devices I have.  You can go with a new device, but it might not stop you from tweaking..just from changing opamps in that device.


 


 Agreed 100% Rob. I have owned amps/dacs with no capacity for rolling opamps and once you know the limitations of what they are capable of where else can you go. I get very exited at the thought of new opamps coming through from the likes of TI, National and Analogue Devices etc. I've been testing the OPA1611/1641 family of late to good effect and looking forward to more new stuff.
   
  My favourite opamp of the moment, just so you know is the LME49990. In the right circuit it is tube like, nice warm full sound yet retaining those beautiful micro details and transients we so love. I have been swapping these into most of my amps the last few months....


----------



## PurpleAngel

Quote: 





spudharris said:


> Agreed 100% Rob. I have owned amps/dacs with no capacity for rolling opamps and once you know the limitations of what they are capable of where else can you go. I get very exited at the thought of new opamps coming through from the likes of TI, National and Analogue Devices etc. I've been testing the OPA1611/1641 family of late to good effect and looking forward to more new stuff.
> My favourite opamp of the moment, just so you know is the LME49990. In the right circuit it is tube like, nice warm full sound yet retaining those beautiful micro details and transients we so love. I have been swapping these into most of my amps the last few months....


 

 Know where I can find three LME49990 DIP-8?
   
  EDIT, just ordered three LME49990MAs from AVNET
  Now need to find a place to order the SOIC DIP adapters?


----------



## PurpleAngel

Anyone ever deal with AVNET Electronics Marketing?
  They sell the LME49990MAs for $2.85.
   
  EDIT, guess it does not mater now, ordered them anyway.
   
  Now where to find quality SOIC to DIP-8 adapters


----------



## ecohifi

Quote: 





purpleangel said:


> Anyone ever deal with AVNET Electronics Marketing?
> They sell the LME49990MAs for $2.85.
> 
> EDIT, guess it does not mater now, ordered them anyway.
> ...


 


 go bact to post 3600 of page 240


----------



## PurpleAngel

Quote: 





ecohifi said:


> Go back to post 3600 of page 240


 

 Thank you, that helped.


----------



## genclaymore

Quote: 





robscix said:


> Opamp rolling is just a sign of wanting to get more out of what you have..IMO.  If you move to a device without opamps for instance, you will just find something else to change and mod.  To me the quest for better audio is a part of the fun.  Trying to tweak, tune and choke more sound quality out of the devices I have.  You can go with a new device, but it might not stop you from tweaking..just from changing opamps in that device.


 


 The  NFB - 12 does have tweaking that you can do with its 9 Digital Filter user settings. That you set by Jumpers, that's was one of the things that i saw that you could do with it.


----------



## PurpleAngel

What's the best solder to use when mounting SOIC (LME49990MA) on to the DIP-8 adapter.


----------



## SpudHarris

Cardas for sure. Low melting point so less chance of frying your chip...


----------



## Mad Max

Add WBT Silver and Radioshack silver to that list, and for the same reasons as Cardas, lol.


----------



## ecohifi

Electrical resistance is low on most metals, copper is the most value for money where silver is the best.  Combine 2 metals like solder and the electrical resistance increases drastic. add a third metal like silver and it increases to the point it is useless as conductor!  I would strongly stick to the basic of basic but do take Spud Harris's advise.


----------



## PurpleAngel

Quote: 





ecohifi said:


> Electrical resistance is low on most metals, copper is the most value for money where silver is the best.  Combine 2 metals like solder and the electrical resistance increases drastic. add a third metal like silver and it increases to the point it is useless as conductor!  I would strongly stick to the basic of basic but do take Spud Harris's advise.


 

 I bought about ten feet of Cardas off eBay earlier this year.


----------



## Mad Max

This is getting off-topic now, but I really wonder about that eBay cardas solder seller that sells the stuff by the handful of feet at a time.  Compared to the Cardas solder that comes with Cardas HPSC connectors, I can't help but think that the ebay stuff sold by the few feet at a time is fake or some kind of imitation or something.  Real Cardas is shinier and flows better.
 Silverextra (formery chaceii) or whatever he goes by these days used to charge more for Cardas as well, so I wonder what's going on.  The next time that I buy that solder, I will buy a spool from one of the authorized Cardas dealers, which I should have done from the beginning.


----------



## SpudHarris

I've bought from ''The Better Audio Company'' Via E-bay for ages and also get my Rosin Flux from them.
   
  Yes we are getting a little off topic so I have a question for those of you in the know.
   
  I really like OPA602 but the OPA602CM (TO99) sounds absolutely amazing in my HiFiMan EF-5, I mean it beats any other I've tried and I've got all the well known's.....  I swapped a few chips around the other night and ended up where I started as you do. I put the dual OPA602CM module back in the EF-5, switched it on and went to make a coffee. When I came back in the room it was filled with this weird smell, almost like antiseptic (TCP). I though the kids had been messing around with the 1st aid kit or something but turns out I'd put the TO99 module in the wrong way and fried 2 of my 602CM's. I struggled to find these originally as they are obsolete now and rare as Hens Teeth. Does anyone know where to get them (not you Leeperry! I contacted that guy in Canada/India and not sure I want to buy 10 from his bay listing). I had 2 spare but can't bare being without them. anyone???


----------



## leeperry

I bought a most likely genuine spool of Cardas quad and it had the exact same nasty smell as that guy selling small lengths of it on ebay.
   
  OPA602CM cannot be bought from anyone else than this indian crook, so bite the bullet or forget about the whole thing. Buying through ebay provides buyer protection anyway, it's a whole different story when buying from his website.


----------



## SpudHarris

You're right but the listing went up the day after I contacted him as did the price on his site..... the listing on e-bay is for 10 off but singles can be bought on his site. Man he does make it difficult. I appreciate your help though, thanks. I'll look at the funds and see if I can risk $200.


----------



## Tribbs

A word about silver bearing solder.  Silver tarnish (silver sulfide and silver chloride), which will undoubtedly occur, is not a good conductor of electricty.  Since electrons generally flow on the surface of a conductor any tarnished silver is bad.
 
Silver-content solder (generally 2%) requires a higher temperature to solder and is more difficult to remove when de-soldering.  Higher temperature means a better chance of damaging a PC board trace by 'lifting' the pad because the adhesive used to attach the pad to the PC board material has been overheated. Use silver-content solders only when required to do so.


----------



## Mad Max

Doesn't 60/40 solder tarnish as well anyway?  I assume older electronics use 60/40 or something, and they always have tarnished joints by now.
  And about removing tarnish: http://www.robotroom.com/PCBTarnishEraser.html  
	

	
	
		
		

		
			




   
  Anyway, Cardas Quad melts so dang easily, followed closely by WBT silver and Ratshack silver solders.  Even a couple years later, the joints they made still melt again pretty easily, so they are fine choices that can help you keep the temperature that you work with to a minimum.


----------



## BrianDonegan

> Doesn't 60/40 solder tarnish as well anyway?  I assume older electronics use 60/40 or something, and they always have tarnished joints by now.


 
   
  No. Tin/Lead does not tarnish.
   
  Degradation of old solder joints is typically caused by the acidic flux left on the board (not properly cleaned off in most electronics due to cost).


----------



## ecohifi

Quote: 





briandonegan said:


> No. Tin/Lead does not tarnish.
> 
> Degradation of old solder joints is typically caused by the acidic flux left on the board (not properly cleaned off in most electronics due to cost).


 

 Bad solder joints are caused by someone who is a novice at soldering or a process in a bath that didn't go right. 
  It is best to stick to the 40/60 normal solder.
  Thx BrianDonegan,  had to get a EE mini Max dac plus because I could get on to your site fast enough to order your gear.  I can only get 3G slow internet- sorry!


----------



## maxietheboss

I am going to buy a Matrix M-Stage in the future and the opamp rolling sounds interesting to me. So far I have seen that the OPA627AP Class A biassed is a popular opamp for the M-Stage. Tamaudio sells these mounted and biased but I have heard that they use fake opamps, can anyone of you tell me if this true, considering the cost ($30 for 2 OPA627AP, adapter and biased) it might be true. How difficult would it be for an absolute beginner to apply a Class A bias to an adapter with 2 OPA627 opamps?


----------



## Mad Max

Not hard if you can solder.  After all, recommended resistor values for biasing OPA627 are posted somewhere in the M-Stage thread.


----------



## Tommy Thong

do anyone compare ada4627-1 n lme49990?how's the sound quality, sound stage, hi-lows?


----------



## G.Trenchev

I've upgraded my amp with OPA1612 today(coming from LM4562).
  Even better details,better treble(LM4562 was rather hot-trebled),better bas definition and a tad warmth(it's welcome).Made sound just perfect.


----------



## SpudHarris

Quote: 





tommy thong said:


> do anyone compare ada4627-1 n lme49990?how's the sound quality, sound stage, hi-lows?


 

 Well, I spent a lot of time with the 4627 and 4637 (my favourite opamp for a while) in various amps and have to say they are very, very good. The LME49990 to my ears is much better in almost every amp I tried it in, I have rolled them into all of my portables and have had them in my EF-5 for a while also.
  
   Sound quality is amazing, almost tube like details/micro details. What I mean is there are details but never, ever harsh, brittle, bright or metalic which is how I found the 49710 over time. LME49990 is my favourite opamp at present I bought 7-8 dual modules from a trusted e-bay source in the US, I can let you have the details if you wish....


----------



## Tommy Thong

to SpudHarris, I totally agreed with you about these two opamp, even i tried Burmester2 CD to test both of them,
  these are my little collection


----------



## Tommy Thong

to G Trenchev: "I've upgraded my amp with OPA1612 today(coming from LM4562).
  Even better details,better treble(LM4562 was rather hot-trebled),better bas definition and a tad warmth(it's welcome).Made sound just perfect"
   
  My suggestion: you need to try the LME49990, My friend


----------



## Tribbs

Quote: 





tommy thong said:


> My suggestion: you need to try the LME49990, My friend


 

 You have my interest peaked.  I ordered a pair.


----------



## Tommy Thong

where is this lme49990 gonna try on?soundcard or cdplayer or preamp?


----------



## qusp

aha, so Nigel finally feels some of the lme49990 love
   
  best single evaaar!


----------



## Tommy Thong

so far, i tried to compare lme49990, lme 49860, ada4627-1, opa827 n opa1641 on my denon cdplayer, still, i feel lme49990 is the best suit opamp ic


----------



## SpudHarris

Yes buddy, been swapping them ito everything I own haha. They are unreal!! That said I fancied a change with the Fi-Q last night and dropped the ADA4637B's back in, they are class also.
   
  Been speaking with Ryuzoh of late about the Fi-Q and cans like LCD-2 and HE-6. Switch 1 on / Switch 2 off and with the LMW49990 have both J1/J2 switched on, it's scary to think a little amp like the Fi-Q (well little compared to some home amps) can sound so good with such hard to drive cans.....


----------



## Tommy Thong

btw,you ordered from ebay seller, did u trust them to sell the original ic? coz my exp,i bought a few of them but they sold the fakes to me


----------



## ijchan223

not sure if this is news to you all but you can request free samples form semi-connector places like TI, NS, etc


----------



## SpudHarris

I have a few trusted sources and yes one or two are from e-bay. I have ordered from AudioJade on a few occasions and never had problems. I did get stung by a seller in the early days when I didn't know what to look for but I worked with TI's counterfeit taskforce and got my money back for fake OPA637BP's. The only thing I would say about AudioJade is read the listing as some of the IC's are used. They do state this so it's not underhand.... I have some OPA627SM's on order from them at the moment.
   
  The LME49990's I got from here and the service has been excellent. I've bought 6 modules from this guy.
   
  I do get samples here and there to get the flavour of certain chips but some of the better tolerance or spec versions aren't always available as samples so I buy a lot also.


----------



## ROBSCIX

I built a few LME49990's last week but I have yet to test them.  I have received great feedback from others though on these opamps.  Maybe I will toss them in a circuit this weekend.


----------



## Tommy Thong

Quote: 





spudharris said:


> I have a few trusted sources and yes one or two are from e-bay. I have ordered from AudioJade on a few occasions and never had problems. I did get stung by a seller in the early days when I didn't know what to look for but I worked with TI's counterfeit taskforce and got my money back for fake OPA637BP's. The only thing I would say about AudioJade is read the listing as some of the IC's are used. They do state this so it's not underhand.... I have some OPA627SM's on order from them at the moment.
> 
> The LME49990's I got from here and the service has been excellent. I've bought 6 modules from this guy.
> 
> I do get samples here and there to get the flavour of certain chips but some of the better tolerance or spec versions aren't always available as samples so I buy a lot also.


 


 opa627sm?wow.. for how much is it(the price)?


----------



## genclaymore

Any one know if using 2x LT1122 with a  adapter will have any issues in a Matrix M-Stage that I waiting on to to come?


----------



## Mad Max

I may have that chip, I'll check.


----------



## Mad Max

I'm not finding any issues at the output of the amp.  Sounds fine.


----------



## genclaymore

Thx, i heard they sound similar to the OPA627 or 827. Is that true?


----------



## Mad Max

I do not find it similar to OPA827 or OPA627.  It reminds me of the other LT chips that I've rolled, lol, certainly not any BB or ADI chips.  I would recommend OPA602BP if you want a really good DIP chip for the M-Stage, OPA827 if you can solder.


----------



## SpudHarris

Quote: 





mad max said:


> I do not find it similar to OPA827 or OPA627.  It reminds me of the other LT chips that I've rolled, lol, certainly not any BB or ADI chips.  I would recommend OPA602BP if you want a really good DIP chip for the M-Stage, OPA827 if you can solder.


 

 x 2 on the OPA602BP. Fantastic OpAmp for sure, I like it a lot more than the OPA827 but still roll that now and then when I fancy a change.
   
  I don't know why but I haven't found an LT OpAmp that I've fallen head over heals with in any of my amps/applications. I guess I came close with the 1363 and 1468....


----------



## qusp

Quote: 





genclaymore said:


> Any one know if using 2x LT1122 with a  adapter will have any issues in a Matrix M-Stage that I waiting on to to come?


 


  its a very nice chip. one of the few jfet input opamps LT make (some will know I favor jfet input stages). not too wide bandwidth to cause issues without compensation, jfet input so shouldnt interact too much with the preceding stage, low noise, good slew rate and pretty decent PSRR. very nice indeed, one of the better LT amps for audio. LT have pretty much unequaled performance for instrumentation stuff, but can as a result not suit some peoples taste due to being a bit analytical. 
   
  what is it replacing and is it for IV stage or buffer? as a buffer it is unity gain stable, but doesnt particularly like capacitive loads, so will depend on your headphones and cables, you could put a little resistance at the output to buffer it from the capacitive loading
   
  sorry for the wordy answer
   
  in a word, basically ..no i dont foresee any problems


----------



## qusp

Quote: 





ijchan223 said:


> not sure if this is news to you all but you can request free samples form semi-connector places like TI, NS, etc


 

 yeah but if you dont intend on ever becoming a designer, or buy a fair bit of opamps to offset the cost of that and the express shipping. i reckon its a bit sly. fortunately i've been in a position to give back a bit lately. people like spud and others in this thread buy a crapload as well, so thats cool and they also recommend chips on here which probably nets them some sales
   
  pretty sure everyone in here was aware of this


----------



## i_djoel2000

hi.. can anybody gives me recommendation for fet opamps that work with minimum +/-5V supply?
   
  dual opamp is more preferable 
   
  so far i only know opa1642, ad8620, and opa827


----------



## Mad Max

Quote: 





qusp said:


> its a very nice chip. one of the few jfet input opamps LT make (some will know I favor jfet input stages). not too wide bandwidth to cause issues without compensation, jfet input so shouldnt interact too much with the preceding stage, low noise, good slew rate and pretty decent PSRR. very nice indeed, one of the better LT amps for audio. LT have pretty much unequaled performance for instrumentation stuff, but can as a result not suit some peoples taste due to being a bit analytical.
> 
> what is it replacing and is it for IV stage or buffer? as a buffer it is unity gain stable, but doesnt particularly like capacitive loads, so will depend on your headphones and cables, you could put a little resistance at the output to buffer it from the capacitive loading
> 
> ...


 
   
  It will drive a discrete diamond buffer.  It runs a bit hot, probably because of the socketed adapter, I think.


----------



## SpudHarris

Quote: 





qusp said:


> yeah but if you dont intend on ever becoming a designer, or buy a fair bit of opamps to offset the cost of that and the express shipping. i reckon its a bit sly. fortunately i've been in a position to give back a bit lately. people like spud and others in this thread buy a crapload as well, so thats cool and they also recommend chips on here which probably nets them some sales
> 
> pretty sure everyone in here was aware of this


 

 100% agree.
   
  I've had samples (mainly TI) but I still support the company because I buy the better tolerance/spec opamps from Farnell once I know if they are for me. Farnell offer a next day delivery here in UK and are reasonable with their pricing so I don't generally look elsewhere unless I'm after obselete or hard to get stuff (damn you OPA602CM).....
   
  Anyhooo, just ordered 4 x LT1122's off Farnell in my quest for an LT OpAmp that bites me.


----------



## Mad Max

1122 at least sounds very clean.  Funky rectangular soundstage and a pinch cold.


----------



## i_djoel2000

Quote: 





i_djoel2000 said:


> hi.. can anybody gives me recommendation for fet opamps that work with minimum +/-5V supply?
> 
> dual opamp is more preferable
> 
> so far i only know opa1642, ad8620, and opa827


 


  anyone?


----------



## Tommy Thong

hi Pak Djoel,
  did you try lme49720 (dip8) or lme49710ma(using socket)?both of them works at+-5volt
  tommy


----------



## Tommy Thong

Quote: 





mad max said:


> 1122 at least sounds very clean.  Funky rectangular soundstage and a pinch cold.


 

 i want to test them, so order a pair of them


----------



## i_djoel2000

Quote: 





tommy thong said:


> hi Pak Djoel,
> did you try lme49720 (dip8) or lme49710ma(using socket)?both of them works at+-5volt
> tommy


 


  hi tommy, thanks for the response
   
  i do have both lme59720 & LME49710, and i know both work at 5v. actually i'm looking for fet opamp to do rolling opamp in my pimeta, which circuit has been optimized to utilize fet opamp and i want to stick to the rule (i've tried lm4562 in pimeta though, they sound quite good)


----------



## Tommy Thong

my pimeta runs with lme49990, sounds natural n great


----------



## SpudHarris

Quote: 





mad max said:


> 1122 at least sounds very clean.  Funky rectangular soundstage and a pinch cold.


 

 Soldered mine up this evening and dropped them in my Fi-Q and P4. I like them a lot so left them in to audition over time. They are very, very nice.


----------



## SpudHarris

Think at long last I may have found an LT OpAmp that makes me smile.....
   
  I have been listening with the LT1122 most of this evening with my Fi-Quest being fed by CLAS and I am loving this OpAmp. Unfatigueing but still crisp and clear and transients at least equal to LME49990. Very, very slightly cool side of neutral to my ears and a nice compliment to my growing collection. The P4 and Fi-Q sound amazing with these


----------



## Tommy Thong

oh really...My LT1122 isn't coming yet from LT


----------



## SpudHarris

As they were only about £5 each I just got a next day Farnell delivery. These are really great OpAmps especially in the Fi-Q (Jeremy, you need to try if you haven't already)....


----------



## Mad Max

OPA1662 is impressive and kind of natural upon initial listening.  Very good imaging and layering of the sound, thick sound, very transparent, very clear, very clean, it's soundstage is more intimate than OPA602, 827, and 4627, but could be a bit more relaxed.  Vocals are a pinch more fleshed out, or maybe it seems that way because it is more intimate, I'm not sure.  There is a slight hint of warmth to the sound.
 I'm loving the sound.  OPA1652 seems to sound the same, just a bit less clean and clear.  Each one has a 22nF ceramic psu bypass cap, they run lukewarm with 30V.


----------



## SpudHarris

I'll check them out also, thanks Max


----------



## genclaymore

Too bad its in soic and not both Mdip and soic.


----------



## Tommy Thong

its brandnew chip from ti, need to try


----------



## SpudHarris

Mine are on route. I'll get them soldered up as soon as they get here and report back. I'm still loving the LT1122 in my ibasso P4. I've put OPA637BP's in my Fi-Quest and just using it in high current mode for my LCD-2 and HE-6, the OPA637's need too much gain to use them with IEM's.


----------



## SpudHarris

Hmmm... bin rollin' again this evening and found an awsome synergy more by luck than judgement. I remember a while back having a few conversations with certain guys about the OPA1602, I bought 2 of them and forgot I had them. I have so many different OpAmps I don't know what made me think of them but they were nestled in the corner of my spares box and thought I'd give them a blast.
   
  I have only tried them in my ibasso PB2 via CLAS and have to say I am mighty impressed. Anyone else tried these?? It's late here 11:30pm and my hearing has usually peaked by now and I find it hard to find material or signatures to make me sit up and take notice but for some reason I have to keep listening...... Set up is Class into DB-2 into PB-2 and Westone ES5 and listening to mainly Ultimae/Altar Records/CelestialDragon and Interchill type material.


----------



## Mad Max

1602 has a lovely midrange, but its bass and soundstaging aren't all that great.  I like ADA4898 or OPA827 better as far as bipolars.


----------



## genclaymore

After trying the 2x1115 in the buffers of my X-FI titanium hd Pci-e with the OPA602BP in the matrix M-Stage. I started to roll op-amps for the I/V's of the sound card with 2x OPA2111KP which I liking so far with the combination.  With my DT880 pro 250.  I had 2x LT1057ACN8, in the I/V's but I didn't like it with the combo.


----------



## SpudHarris

OPA1662's are here. Will solder up and give some thoughts later. Missus is out tonight so plenty of me time!


----------



## Tommy Thong

OPA1662 sat in my cdplayer start this morning n under testing for hours, i thought they need to pass "100hours broke-in step"


----------



## SpudHarris

Well as is the case with rolling, the 1662's sound better/worse in different amps. Obviously a result of a closer to optimised circuit or additional components.
   
  What I can say is that in my Fi-Q the 1662's are absolutely amazing (it's a great amp) and there is a sweet synergie between this Opamp, the Fi-Q and my LCD-2's. I'm using my ipod classic (lossless) via CLAS into Fi-Q so source is also good but this Opamp is very, very good and the way everything sounds in this particular set up, I don't think I would change a thing.... Nice!
   
  For my DB-2/PB-2 set up the 1602's seem to be the ones to beat.


----------



## Pars

Would any of you opamp aficionados be able to recommend an opamp for SE->bal conversion and buffering in a CD player? I am currently using THS4031s for the I/V conversion (with a lot of bypassing) and AD8599s for the conversion/buffer stage. I am going to be switching to a discrete I/V stage, though the THS4031s do sound good, but not as good IME. The stock components were NE5534s for I/V and OPA2604s for the buffers.
   
  ADA4898-2 maybe?


----------



## Mad Max

Isn't OPA1632/THS4131 designed to take a SE signal and pump out a balanced signal?  It's pin-out is very different from a lot of other opamps like 4898, 8599, 4031, etc.  I wanted to try it out, but reading people's comments on its use on diyaudio makes it seem to be pretty complicated business, more than I would like to bother with, so I didn't try it out.


----------



## SpudHarris

Yes, it is different. I bought some not knowing and soldered up in the usual way but when I tried them out it was like listening with a pillow over my ears. Thought I'd overheated them while soldering until I read up properly. Luckily I didn't damage anything....


----------



## Pars

I may take a look at those. Are those the ones that TI had to license Nelson Pass' SUSY for? Otherwise, I may try transformers for the first time...


----------



## genclaymore

I started to wonder how 2x LT1358CN8  and 2x OPA602 BP in my sound card would sound with the 2x LT1115CN8's that I have in my Matrix M-Stage. So far I like this combination. For me it seems to work very good with each other. With my DT880 pro-250.


----------



## Tommy Thong

Quote: 





mad max said:


> OPA1662 is impressive and kind of natural upon initial listening.  Very good imaging and layering of the sound, thick sound, very transparent, very clear, very clean, it's soundstage is more intimate than OPA602, 827, and 4627, but could be a bit more relaxed.  Vocals are a pinch more fleshed out, or maybe it seems that way because it is more intimate, I'm not sure.  There is a slight hint of warmth to the sound.
> I'm loving the sound.  OPA1652 seems to sound the same, just a bit less clean and clear.  Each one has a 22nF ceramic psu bypass cap, they run lukewarm with 30V.


 


 Report back after compare between OPA1662, LT1122 and LME49990, for my taste, i still like LME49990's natural sound than LT1122 or OPA1662 BUT these 3 opamp are nice opamp chip so far, they just have a little bit different each other, OPA1662 have a bit sweet on mids(as BurBrown opamp family) also very clean, nice sound-stage and LT1122 have a nice sparkling on tops-end n details
   
  Btw, i keep using OPA1662 on my cdplayer coz' love their sweet-soft mids


----------



## SpudHarris

Nice one guys, I too am loving the OPA1662 as I write. I have dropped the OPA602CM's out of my EF-5 and am really enjoying the change....
   
  I agree 100% Tommy, the LME49990 is also a favourite of mine and yes the LT1122 does have a nice sparkle to it. I like them all but for different reasons. I also rate the OPA1602 very highly. I guess if I had to choose one to keep I think it would be the LME49990 as It sounds great in almost all of my amps.


----------



## ecohifi

HI Guys,
   
  where did you guys get the OPA1662.  Digikey and Element 14 have zero stock!!!!  I think that TI is out as well!!!!


----------



## Mad Max

I got a sample from TI, lol.


----------



## Tommy Thong

hi Ecohifi
  I  got from TI too, give it try to order again


----------



## ecohifi

How extended and detail is the OPA1662 compared to the LME 49990 or the AD4627_1brz????


----------



## Mad Max

Equally as, but I add psu bypass caps, so your own observations may not be the same.  LME49990 has the edge at soundstaging, however.


----------



## ROBSCIX

Looks like I got some new modules to build and test.
   
  I am also considering ordering some caps for some testing also with the opamps.


----------



## fabio-fi

Im not an expert into DIY (started learning few months ago, building a cmoy) 
   
  Anyone know about the Burson opamps? i know the amps but i want to know if somebody have tried them. 
   
  There's a giveaway currently.


----------



## ROBSCIX

Quote: 





fabio-fi said:


> Im not an expert into DIY (started learning few months ago, building a cmoy)
> 
> Anyone know about the Burson opamps? i know the amps but i want to know if somebody have tried them.
> 
> There's a giveaway currently.


 

 Some like them and some do not.  They are just opamps built from discrete components so that can have pros and cons depending on how you look at it.
  There are many discrete opamps out there you don't have to pay ultra high prices to test them out.  Check out the Audio GD line-up.


----------



## fabio-fi

Quote: 





robscix said:


> Some like them and some do not.  They are just opamps built from discrete components so that can have pros and cons depending on how you look at it.
> There are many discrete opamps out there you don't have to pay ultra high prices to test them out.  Check out the Audio GD line-up.


 


  Thanks for the reply Rob. After doing some research, i've seen some people is using them with the miximax dac. Im very tempted to try this upgrade.


----------



## akiroz

Quote: 





fabio-fi said:


> Im not an expert into DIY (started learning few months ago, building a cmoy)
> 
> Anyone know about the Burson opamps? i know the amps but i want to know if somebody have tried them.
> 
> There's a giveaway currently.


 


   
  I've heard how they sound in Burson's HA-160 amp and i've got to say, its nothing special and ridiculously over priced, I could make a better sounding discrete OP with just 10 US$


----------



## fabio-fi

Quote: 





akiroz said:


> I've heard how they sound in Burson's HA-160 amp and i've got to say, its nothing special and ridiculously over priced, I could make a better sounding discrete OP with just 10 US$


 


  Awesome! you should start your own company. 
	

	
	
		
		

		
		
	


	



  (no offense)


----------



## ROBSCIX

Quote: 





fabio-fi said:


> Thanks for the reply Rob. After doing some research, i've seen some people is using them with the miximax dac. Im very tempted to try this upgrade.


 
  Check out some of the Audio-GD discrete products, they are cheap enough to play with without draining your wallet.  If you don't like them you can turn around and sell them without losing too much.


----------



## Mad Max

What does the price matter?  If he wins, he gets a couple of them for free.  If he doesn't like them, he knows where he can sell them.  ;D


----------



## ahmadmfz

Hello guys. Currently, i'm thoroughly loving the sound of the AD743JN with my ibasso p3. However.. it sucks too much battery life. Can anyone recommend me something similar sounding that doesn't require so much power? It's lush and full sounding yet maintains a linear treble to bass presentation. At least that's what i hear.. Pairing it with JH5 and an imod/J3.


----------



## Mad Max

OPA209


----------



## genclaymore

How does that OPA209 sound and is it available in Dip-8. Also if does any one know how the LT1013 AN8 sound.


----------



## SpudHarris

I wasn't keen on the OPA209 in my specific applications but I did own the "2Stepdance'' which employs 5 of them and that was quite an amazing sounding amp. I think they are only SOIC...


----------



## hanssen4

which is better,
   
  lt1361 or lme49720
   
  if i search for clarity, instrument separation, detail, soundstage, & bright.. thx


----------



## smengy1

Hello!!  I am a x-Meridian  7.1 2g owner,  and have made a custom dual To-99 lme49710HA board for its main out. 
  http://www.vinylengine.com/turntable_forum/viewtopic.php?f=52&t=40882
  You can read my rants here.
   
  I modded my turntable with Fine 99.999 headshell wires and clips,  and custom 999 silver cored RCA plugs.
   http://www.vinylengine.com/turntable_forum/viewtopic.php?p=323623
   
  So i started recording my vinyl.  I have found the 49710HA's to be incredibly,  incredibly detailed. The prescience of fading signals reamain perfect. With the silver wires the raw listening is harsh.
  When I play back the recorded file in Diamond Cut Audio,  it sounds neutral.  When I play it back with windowsmedia player, its sounds warm. When I play it back with Foobar,  blah its tinny.  I shift the playback to digital 48khtz.  Good lord last night I was trying to record Hawkwinds- Warrior
  On the Edge of Time,  and the part in the Golden Void pt2,  where the synth comes screaming in  had me jumpin in my seat,  dodging death rays, and covering my ears!!  Very Very detailed,  no dropping or smearing of signal at all.   But a lil too harsh.
   
  Any good reccomendations?   I have one to 99 board left,  and would like to stick to that dual TO-99 as the sound is really incredible.
   
  I have to say that the sound card,  played back through a Marantz sr7300,  into some infinity speakers with ribbons,  have made the Infinitys come alive!!  The sr 7300 has hmm looks like 2068's in it.
   
  So I guess I'm looking for a just as detailed opamp,  just warmer, with more bass.  Still the 49710's do sound insane!!!   I will keep them for the recording part,  but want to have some opamps that will wow me when I play it back.  49710's are just a tad thin.
   
  Thanks!


----------



## Monago

A few questions, for those in the know...
   
  Would the LME49990 be compatible with the M-Stage? If so, what would be required to make it fit (assuming it isn't just drop-in)? Finally, would the drop-in class A bias mods be compatible with a fitted LME49990? 
   
  Edit: I've heard incredible things about this opamp, and would love to give it a try asap!


----------



## SpudHarris

The 49990 would be compatible as a drop in replacement. Do you know what opamps the M-stage takes in terms of singles or duals? Either way you would need 2 x 49990 and they would either be 2 x separate modules or a single module like this. I have bought 5-6 of theses of this guy and the soldering is mint and delivery quick.
   
  I tried the class A mod and thought it made the sound thinner, more treble detail but not as full sounding, I like it without that tweak. It it a great sounding opamp, one of my firm favourites....


----------



## ROBSCIX

To the hardcore opamp swappers here,  If you could have an adapter made to have any features you wanted what would it have?
   
  I am considering designing and fabricating some adapters for common type we use.  I have a few things I want to see but It would be nice to get some input from other modders also.
   
  So what do you think?


----------



## Monago

Quote: 





spudharris said:


> The 49990 would be compatible as a drop in replacement. Do you know what opamps the M-stage takes in terms of singles or duals? Either way you would need 2 x 49990 and they would either be 2 x separate modules or a single module like this. I have bought 5-6 of theses of this guy and the soldering is mint and delivery quick.
> 
> I tried the class A mod and thought it made the sound thinner, more treble detail but not as full sounding, I like it without that tweak. It it a great sounding opamp, one of my firm favourites....


 

 Ah! That's precisely what I was looking for!! Thank you for the link SpudHarris!! 
   
  I'm going to order up one of those right now 
	

	
	
		
		

		
			





. SO excited to give this opamp a try!


----------



## AnAnalogSpirit

Quote: 





robscix said:


> To the hardcore opamp swappers here,  If you could have an adapter made to have any features you wanted what would it have?
> 
> I am considering designing and fabricating some adapters for common type we use.  I have a few things I want to see but It would be nice to get some input from other modders also.
> 
> So what do you think?


 


  I've lurked for awhile, am still quite new to opamps, but have enjoyed my iBasso D10, and Auzen X-Meridain 7.1 (first gen) both with DIP-8 sockets... It would be nice to have adaptors that are made of better quality materials than say Brown Dog adaptors, or random eBay items. My interests would include copper or gold traces (like on those nice iBasso adaptors), and the metal conductors like pins and sockets, it would be nice to have them made of OFC copper, with decent gold plating. Not to be a snob, or go down the whole "better cables" argument with regard to adaptors, please, but for such a short signal path; maximizing conductor quality seems worthwhile.
   
  Some adaptors I have not seen as an all in one or integrated type are: TO-99 to DIP-8 adapters, esp dual socket TO-99 to DIP-8 adapters (for single opamps). I realize I may just have yet to run across them, as I am quite fresh at opamp rolling, but I say the post, and thought I'd give my input.


----------



## Mad Max

Quote: 





robscix said:


> To the hardcore opamp swappers here,  If you could have an adapter made to have any features you wanted what would it have?
> 
> I am considering designing and fabricating some adapters for common type we use.  I have a few things I want to see but It would be nice to get some input from other modders also.
> 
> So what do you think?


 

 Pads for psu bypass caps is a must.  Since class A biasing is so popular, pads for that should be a must as well - whether biasing with just a resistor or going with the JFET cascode thing.  All the pads ought to at least be a little long like on the iBasso adapters, not just for ease of soldering, but for modifications/tweaks/etc. in general.  Also, a possibility of directly soldering pin 4 to the exposed underside pad that some chips have would be nice, too, or the possibility of connecting the underside pad to a trace that leads to a small hole on the pcb for a wire and thus a connection to ground.


----------



## hknymz

and this mine opamp mod  i need some caps mod maybe?
   

  Quote: 





smengy1 said:


> Hello!!  I am a x-Meridian  7.1 2g owner,  and have made a custom dual To-99 lme49710HA board for its main out.
> http://www.vinylengine.com/turntable_forum/viewtopic.php?f=52&t=40882
> You can read my rants here.
> 
> ...


----------



## smengy1

Been looking through stuff and am thinking about OPA627SM's and or a OPA2111--?.   There are AM, BM, and KM versions of these.  All reviewers have
  said they are fuller sounding.  Just don't know what version they were talkin about.    CMON guys!!!  249 pages of this stuff, and no one can recommend anything???
   
  Husker Du New Day rising almost split my eardrums!!!   It is the most trebly album I have.  Fuzztone distortion!!  Definitely made my lme49710HA's emit screetching.
  hell!!!  Still on tamer less trebly records the LME's are still incredible,   what would have the same detail,  just warmer with more bass? 
   
  Anyone?!?!?!?


----------



## SpudHarris

I recon you've hit the nail on the head with OPA2111AM - I'm a big fan of this Opamp. Great detail and resolution yet full and warm also. If you go for either this or OPA627SM I'd definately get them from a reputable source (especially the 627's).
   
  I probably still have a few 2111AM's in my box if you are interested...


----------



## smengy1

Hmm ok OPA2111 AM's.   But I read in the spec sheets its a dual to-99-8.  So I only need one of them?  Or 2?  Its going into the Main Front Channel of
  my Auzentech card, the regular old 2 channel stereo output.
   
  Also ive been readin about class A adpters cleaning up the sound of LME49710's.  What is that?  Link to picture appreciated!


----------



## genclaymore

You only need one OPA2111AM, its a dual channel metal op-amp.


----------



## SpudHarris

Well guys, I'm trying this rather odd looking Opamp - LME49880
   




   
  I have to say I'm liking it a lot. I've got two of them in my balanced PB-2 and they are very, very clean. Possibly the cooler side of neutral but nice detail and soundstage. A lot to like in this chip.... Anyone else have experience with it?


----------



## qusp

Quote: 





mad max said:


> Pads for psu bypass caps is a must.  Since class A biasing is so popular, pads for that should be a must as well - whether biasing with just a resistor or going with the JFET cascode thing.  All the pads ought to at least be a little long like on the iBasso adapters, not just for ease of soldering, but for modifications/tweaks/etc. in general.  Also, a possibility of directly soldering pin 4 to the exposed underside pad that some chips have would be nice, too, or the possibility of connecting the underside pad to a trace that leads to a small hole on the pcb for a wire and thus a connection to ground.


 

 connection to ground? opamps dont know what ground is, the exposed pad (power pad) is for heatsinking the die generally (thats why its connected to the ground plane, for thermal connection, not due to needing an electrical ground connection) and while sometimes also connected to the rails or a reference voltage to servo the output, there is no benefit to provide a point for a wire to connect as it will not help with heatsinking at all, in fact using a powerpad package on an adapter would be almost certain to involve over-temp death to the device.


----------



## sssboa

Will LM7171 work as replacement for MC33078N provided that I will put 2x LM7171 on an adaptor that is popularly sold for BB OPA627. I seek even cleaner crispier sound than LM4562.
   
  OP AMP, VOLT FEEDBACK, 7171, DIP8

 Op Amp Type:High Speed
 No. of Amplifiers:1
 Bandwidth:200MHz
 Slew Rate:4100V/Âµs
 Supply Voltage Range:5.5V to 36V
 Amplifier Case StyleIP
 No. of Pins:8
 Operating Temperature Range:-40_C to +85_C
 SVHC:No SVHC (20-Jun-2011)
 Amplifier Type:Voltage Feedback
 Base Number:7171
 Gain Bandwidth:140MHz
 IC Generic Number:7171
 Input Offset Voltage Max:7mV
 Logic Function Number:7171
 Operating Temperature Max:85_C
 Operating Temperature Min:-40_C
 Operational Amplifier Features:High Speed
 Package / CaseIP
 Slew Rate:4100V/Âµs
 Supply Voltage + Nom:15V
 Supply Voltage Max:36V
 Supply Voltage Min:5.5V
 Termination Type:Through Hole
   
   
  IC, OP AMP, DUAL AUDIO, 33078, DIP8

 Op Amp Type:Low Noise
 No. of Amplifiers:2
 Bandwidth:16MHz
 Slew Rate:7V/Âµs
 Supply Voltage Range: Â± 2.5V to Â± 15V
 Amplifier Case StyleIP
 No. of Pins:8
 Operating Temperature Range:-40_C to +105_C
 SVHC:No SVHC (20-Jun-2011)
 Amplifier Type:Audio
 Base Number:33078
 Gain Bandwidth:9MHz
 IC Generic Number:33078
 Input Offset Voltage Max:3mV
 Logic Function Number:33078
 Operating Temperature Max:105_C
 Operating Temperature Min:-40_C
 Package / CaseIP
 Slew Rate:7V/Âµs
 Supply Voltage + Nom:15V
 Supply Voltage Max:15V
 Supply Voltage Min: 2.5V
 Termination Type:Through Hole


----------



## T.F.O.A

Hi,anybody knows a good opamp that is neutral, but slightly warm, also has a good (not crazy) bass punch? gonna be using it with audinst mx1.


----------



## Mad Max

Quote: 





qusp said:


> connection to ground? opamps dont know what ground is, the exposed pad (power pad) is for heatsinking the die generally (thats why its connected to the ground plane, for thermal connection, not due to needing an electrical ground connection) and while sometimes also connected to the rails or a reference voltage to servo the output, there is no benefit to provide a point for a wire to connect as it will not help with heatsinking at all, in fact using a powerpad package on an adapter would be almost certain to involve over-temp death to the device.


 
   
  I forgot which ones, but I've seen a few opamps' datsheets specify to not connect the powerpad to the rails, that's why.  But to hell with those chips, you say?
 Forget them then.


----------



## PurpleAngel

It seems the AD797BR is better then the AD797AR, is this then general consensus?
   
  On eBay seller audjade_chn, who seem to have good feedback, is selling 20pcs of (used) AD797BR soldered on to 10 SOIC to DIP-8 adapters
  Price is $79.99 (includes shipping), has anyone here ever dealt with this seller?


----------



## SpudHarris

I have ordered from Audiojade on a number of occasions and always got a genuine item and great service. Off the top of my head the last chips I bought were used OPA111AM (TO99) and OPA637BM (TO99).
   
  I think that the BR version of 797 sounds better but it's not night and day. If you buy them but don't want all 10 modules I'd take a couple off your hands. I have 6 off them but they are all on single adapters which limits some applications (EF-5 for instance)
   
  Let us know how that pans out.


----------



## PurpleAngel

Quote: 





spudharris said:


> I have ordered from Audiojade on a number of occasions and always got a genuine item and great service. Off the top of my head the last chips I bought were used OPA111AM (TO99) and OPA637BM (TO99).
> I think that the BR version of 797 sounds better but it's not night and day. If you buy them but don't want all 10 modules I'd take a couple off your hands. I have 6 off them but they are all on single adapters which limits some applications (EF-5 for instance)
> Let us know how that pans out.


 
  Can not find AudioJade
  But i did find a seller of the AD797BR, called Audjade_chn


----------



## qusp

Quote: 





mad max said:


> I forgot which ones, but I've seen a few opamps' datsheets specify to not connect the powerpad to the rails, that's why.  But to hell with those chips, you say?
> Forget them then.


 


 yeah ive only ever personally seen a thermal connection, which is the most common, or a reference voltage for an output servo (VCOM, which might be what youve seen on opa1632dgn), normally thermal and no point having that on an adapter. not worth catering for either way
   
  @sssboa: i recommend you stay away from the LM7171 with bandwidth of 200Mhz and gain BW of 140Mhz that'll be a bitch to keep stable in an audio circuit on an adapter


----------



## Mad Max

Quote: 





purpleangel said:


> Can not find AudioJade
> But i did find a seller of the AD797BR, called Audjade_chn


 

 That's Audio Jade, lol.


----------



## SpudHarris

Quote: 





purpleangel said:


> Can not find AudioJade
> But i did find a seller of the AD797BR, called Audjade_chn


----------



## PurpleAngel

I ended up buying 10 pre-soldered adapters (20 AD797BR op-amps), I'm really only going to need three adapters, maybe I'll sell off the extras on head-Fi?


----------



## leeperry

Quote: 





purpleangel said:


> I ended up buying 10 pre-soldered adapters (20 AD797BR op-amps)


 

 AD797 was said to be unstable in the I/V of the STX, just so you know.


----------



## G.Trenchev

How much did you pay for them?
  
  Quote: 





purpleangel said:


> I ended up buying 10 pre-soldered adapters (20 AD797BR op-amps), I'm really only going to need three adapters, maybe I'll sell off the extras on head-Fi?


----------



## ZorgDK

Quote: 





leeperry said:


> AD797 was said to be unstable in the I/V of the STX, just so you know.


 
   
  What do you mean by unstable? I think they sound great in the I/V of the ST , no problems here after 6+ months .


----------



## PurpleAngel

Quote: 





g.trenchev said:


> How much did you pay for them?


 

 The 10 pre-soldred AD797BR adapters were $79.99, includes shipping, from China.


----------



## PurpleAngel

Quote: 





leeperry said:


> AD797 was said to be unstable in the I/V of the STX, just so you know.


 
  I heard they were somewhat unstable, but I wanted to try them anyway.


----------



## madwolf

Well Having tested OPA 1662 I have this to add. It is Smooth and Balance.
  It does not have the warmth of AD797, but it is much more clear and open.
   
  Nice catch, Anyone tried the sister of OPA1662, the OPA1652 ?


----------



## Mad Max

OPA1652 is a slight downgrade.
   
  I found 1662/1652 warmer, less open, and less clear than 797B in my gear.


----------



## dumbears

I wonder if LME49990 is more difficult to drive than the other opamps.  I ordered a couple of sample from National/IT.  I tested all of them in O2 (not as buffers), and I can only bearly hear some sound from my K702 even I've turned the volume to maximum.  For other opamps, they're all loud and clear.


----------



## Mad Max

I don't think the O2 is suitable for rolling.
   
  Edit: ADA4610 is finally available!  But only a dual version. so far.


----------



## SpudHarris

Quote: 





mad max said:


> Edit: ADA4610 is finally available!  But only a dual version. so far.


 

  
  Have you had a chance to try yet? I'll buy a couple to try in my various amps and set ups....


----------



## Mad Max

I will in a few days.  =]


----------



## DefQon

Max's dual AD8597, roughly burn in-time around 500 hours equals one word: Fantastic!
   
  I can understand why the AD8599 (essentially 2xAD8597) is one of the best Opamp's around......a very transparent, but sonically synergised and warm opamp that is tiny bit rolled off in the treble section but the bass depth and detail revealing is amazing. 
   
  Put's all the JRC opamp's I've tried to shame and few other AD opamps to shame. But I'm still looking for a opamp that offers a lot of bass impact, warm and tube alike sound sig.


----------



## mataso

In short, which DIP8 op-amps are the better ones for Xonar ST? For now looking at LME49860NA. I don't want op-amps that need adapters and soldering, only plug and play


----------



## genclaymore

You can also give the LT1124ACN8 a shot as well, linear has them and there dual channel op-amps. of course you will need two.


----------



## mataso

I was looking at 1x LM6172 + 2x LME49860NA combo, maybe 1x LM6172 + 2x LT1124CN8 would be better?


----------



## qusp

Quote: 





purpleangel said:


> The 10 pre-soldred AD797BR adapters were $79.99, includes shipping, from China.


 


  these are either fakes or used pulls from recycled equipment, that price is ridiculously low, too low


----------



## PurpleAngel

Quote: 





qusp said:


> These are either fakes or used pulls from recycled equipment, that price is ridiculously low, too low


 
  I'm guessing most scammers use miss-labaled new parts.
  The listing was very upfront, all used op-amps.
  Others have used the same eBay seller and had good things to say about them.
  I'm guessing it's costs them $25-$50 for the parts and $5 shipping.
  I'm going to test them all, keep three, and sell off the rest, for like $10 each.
  If I'm lucky, I will get $70 for 7 pre-soldered adapters.


----------



## qusp

i didnt look at the ad, you didnt mention used so makes more sense. but you are mistaken applying logic to electronics pirates. some of the parts you see faked you wonder how there could be any money in it; often with used parts too, so they can pass them off as NOS more easily. Japanese Toshiba power transistors and jfets, rare mosfets, Dac chips and yes opamps.


----------



## Mad Max

If from Audio Jade on eBay, they are honest and call the chips used.  The listing says new, but they specify that the adapters are what's new, lol.
   

  ADA4610 is badass.  Deep soundstage with razor-sharp imaging, lively sound, incredibly clean, very clear and full treble.  Note attack is rather sharp, just shy of being a bit too much for my tastes but lends itself well to percussion instruments.  Very neutral and mercilessly revealing, just the way I prefer.  =]


----------



## PurpleAngel

Quote: 





mad max said:


> If from Audio Jade on eBay, they are honest and call the chips used.  The listing says new, but they specify that the adapters are what's new, lol.
> ADA4610 is bad ass.  Deep sound stage with razor-sharp imaging, lively sound, incredibly clean, very clear and full treble.  Note attack is rather sharp, just shy of being a bit too much for my tastes but lends itself well to percussion instruments.  Very neutral and mercilessly revealing, just the way I prefer.  =]


 
  Why did you have to mention ADA4610, now I have to make another impulse buy.
  It looks like the ADA4610 do not come in DIP-8, so time to try my hand at soldering.
  Anyway, I did order from Audio Jade.


----------



## PurpleAngel

Quote: 





qusp said:


> I didn't look at the ad, you didn't mention used so makes more sense. but you are mistaken applying logic to electronics pirates. some of the parts you see faked you wonder how there could be any money in it; often with used parts too, so they can pass them off as NOS more easily. Japanese Toshiba power transistors and jfets, rare mosfets, Dac chips and yes opamps.


 
  The seller (Audio Jade) uses the name "audjade_chn" on eBay.
  I figured most electronics pirates would use the word "new", just so they can charge more money.
  My idea is not perfect, but i think it's one way to try and filter out the E pirates.


----------



## SpudHarris

I have bought from them many times and never had any issue, even with what could be considered boutique opamps.
   
  The ADA4610 is incredible  I have 2 off bypassed in my PB-2 and am listening as I write via DB-2 + PB-2 + Clas combo and Balanced AH-D7000's. Oh my, I have work in the morning but I don't want to go to bed.....
   
  Thanks Max for your help on bypassing, I think I am finally getting it. I have had amazing results with OPA827, ADA4610 and OPA1662 opamps, far more success than the Class A resistor tweak which is a bit hit and miss. So thanks for the leg up the bypassing ladder, the cheque's in the mail.


----------



## ecohifi

Quote: 





mad max said:


> If from Audio Jade on eBay, they are honest and call the chips used.  The listing says new, but they specify that the adapters are what's new, lol.
> 
> 
> ADA4610 is badass.  Deep soundstage with razor-sharp imaging, lively sound, incredibly clean, very clear and full treble.  Note attack is rather sharp, just shy of being a bit too much for my tastes but lends itself well to percussion instruments.  Very neutral and mercilessly revealing, just the way I prefer.  =]


 

 Hi Mad Max,
   
  how do the ada4610 compared to the ada4627-1 brz????
   
  Regards
   
  ecohifi


----------



## Mad Max

4610-2B seems to achieve a tighter, more focused and weightier sound versus 4627-1B.  Slightly more prominent treble than 4627 and deeper bass with K701.  Less soundstage depth than 4627.  They otherwise sound the same.  4610 seems to be very easy to stabilize, unlike 4627 which is a PITA.


----------



## ecohifi

Mad Max,
   
  many thnxs for the reply,
   
  ordered a pair of ADA 4610-2brz and AD8599 ARZ as samples thru the ADI web site, unfortunately you can only order 2 of the same item per order as samples, they should be arriving tommorrow according to there delivery instructions.
   
  I have a soft spot for the ADI devices. 
   
  The ADA 4627-1 Brz have a better psu CMRR and lower noise levels than the A version and are better sounding,
   
  The AD 4610-2brz are probably easier to tame than the 4627 due to a reduction in slew rate and non voltage reversal when over driven.


----------



## SpudHarris

Max, are you having any issues when switching off your amps with the ADA4610's? Everything I've tried them in makes a terrible short screeching noise when switching off. I am having to pull my IEM's out first for fear of damaging them.
   
  (Fi-Quest / Ibasso P4 + PB2)


----------



## Mad Max

You dun goof'd somewhere!  o__O'
   
  Or so I reckon.  If you added a cap like I did, it connects across pins 4 & 8 only, right?


----------



## SpudHarris

Yeah, pins 4 and 8 only and all 4 off them are the same. They were the same before bypassing so I don't recon I dun goof'd.... Might be ibasso kit, you got any to try?


----------



## Mad Max

What do you mean "ibasso kit"?
  I don't have anything iBasso except for their adapters.  And I have both of my 4610-2B samples mounted on iBasso adapters.


----------



## SpudHarris

I just mean iBasso amps (Fi-Q / P4 / PB2). I tried the 4610 in my EF-5 tonight and there was no noise when switching the amp off. Just so you know the 4610 doesn't shine in the EF-5 but is fantastic in my other stuff apart from the annoying screech when switching off, guess I'll have to live with it.


----------



## Mutsu

I've just started op amp rolling with my Essence One and was hoping for some advice from people with experience rolling on the One.
   
  I currently have 1x http://www.ebay.co.uk/itm/LME49720HA-LME49720-TO99-DIP8-/190653873559?pt=LH_DefaultDomain_0&hash=item2c63db3d97#ht_1001wt_1270 in the RCA Buffer and
  2x http://www.ebay.co.uk/itm/DUAL-SOIC-LME49990-DIP8-ADAPTER-/190641930863?pt=LH_DefaultDomain_0&hash=item2c6325026f#ht_709wt_1270 in the low pass filter
   
  I'm finding more details than the stock op amps and an improved soundstage, but I'm finding trebles to be a little bright. I'm noticing high hats more often now.
   
  I feel like the sound currently needs slightly more bass to balance the treble out and slightly more attack wouldn't go amiss too.
   
  I was going to order a full set of 49990s to try, but I've heard that the LME4x chips can sound a little bright and now I'm experiencing some of this brightness I'm having second thoughts.
   
  I don't want to be soldering, so if anyone could also advise reputable ebay sellers of compatible chips(Already built to drop into my One) it would be greatly appreciated!


----------



## PurpleAngel

Quote: 





mutsu said:


> I've just started op amp rolling with my Essence One and was hoping for some advice from people with experience rolling on the One.
> I currently have 1x http://www.ebay.co.uk/itm/LME49720HA-LME49720-TO99-DIP8-/190653873559?pt=LH_DefaultDomain_0&hash=item2c63db3d97#ht_1001wt_1270 in the RCA Buffer and
> 2x http://www.ebay.co.uk/itm/DUAL-SOIC-LME49990-DIP8-ADAPTER-/190641930863?pt=LH_DefaultDomain_0&hash=item2c6325026f#ht_709wt_1270 in the low pass filter
> I'm finding more details than the stock op amps and an improved soundstage, but I'm finding trebles to be a little bright. I'm noticing high hats more often now.
> ...


 
  I was able to get 20 pieces of AD797BRs pre-soldered to 10 adapters (dual SOIC to DIP-8) for $80, off eBay, shipped from China.
  The seller is Audio Jade, listed on eBay as audjade_chn.
  I've only tried 3 of the tens pieces, on my Essence STX, they sound good and work fine.
  Some have said the AD797 are not the most stable op-amps, but they work fine on my Essence STX.


----------



## sssboa

*LM4562 *as replacement of *MC33078*
  Can you think of a reason why an amp Beyerdynamic A1 or its exact clone works 100% fine with its stock 2x MC33078 but when refitted with 2x LM4562 it SOMETIMES does not work at all (does not switch on), no sound,the leds before LM4562s are on but the led after them is off and no sound, it fixes when I switch off and back on a few times, with original MC33078s there's no such a glitch. I guess it might be myriads of reasons in opamps and pcb of the amp but maybe you can see something straight from the specs of both opamps below.
    

  IC, OP AMP, DUAL AUDIO, *MC33078*, DIP8 
 Op Amp Type:Low Noise
 No. of Amplifiers:2
 Bandwidth:16MHz
 Slew Rate:7V/Âµs
 Supply Voltage Range: Â± 2.5V to Â± 15V
 Amplifier Case StyleIP
 No. of Pins:8
 Operating Temperature Range:-40_C to +105_C
 SVHC:No SVHC (20-Jun-2011)
 Amplifier Type:Audio
 Base Number:33078
 Gain Bandwidth:9MHz
 IC Generic Number:33078
 Input Offset Voltage Max:3mV
 Logic Function Number:33078
 Operating Temperature Max:105_C
 Operating Temperature Min:-40_C
 Package / CaseIP
 Slew Rate:7V/Âµs
 Supply Voltage + Nom:15V
 Supply Voltage Max:15V
 Supply Voltage Min: 2.5V
 Termination Type:Through Hole
 

   
  OP AMP AUDIO DUAL *LM4562* HF 8-DIP, POWERWISE

 Amplifier Class:AB
 No. of Channels:2
 Supply Voltage Range:Â± 2.5V to Â± 17V
 THD + N:0.00003% @ 2kohm, VS=Â± 15V
 Load Impedance:2kohm
 Operating Temperature Range:-40_C to +85_C
 Amplifier Case StyleIP
 No. of Pins:8
 SVHC:No SVHC (20-Jun-2011)
 Base Number:4562
 Gain Bandwidth:55MHz
 No. of Amplifiers:2
 Op Amp Type:Low Noise
 Output Power Pout:-000mW
 Package / CaseIP
 Slew Rate:20V/Âµs
 Supply Voltage Max:17V
 Supply Voltage Min:2.5V
 Termination Type:Through Hole


----------



## Mad Max

Quote: 





mutsu said:


> I've just started op amp rolling with my Essence One and was hoping for some advice from people with experience rolling on the One.
> 
> I currently have 1x http://www.ebay.co.uk/itm/LME49720HA-LME49720-TO99-DIP8-/190653873559?pt=LH_DefaultDomain_0&hash=item2c63db3d97#ht_1001wt_1270 in the RCA Buffer and
> 2x http://www.ebay.co.uk/itm/DUAL-SOIC-LME49990-DIP8-ADAPTER-/190641930863?pt=LH_DefaultDomain_0&hash=item2c6325026f#ht_709wt_1270 in the low pass filter
> ...


 
   
  The LME brightness is probably due to instability, in my experince. LME49990 is badass.  Another great opamp that you can try and that is not too finicky is OPA602BP.  I would try BUF634P in buffer positions.  These last two chips do not require soldering and are single opamps.
   
  If all else fails for you, then you probably can't go wrong with "an army of AD797" purchased from Audio Jade (audjade_chn) on eBay as leeperry prescribes, lol.


----------



## Mutsu

Yea, I think I'll try ordering the AD797s to try them, shame they take so long to be delivered. Might also try to source some of the others you suggested if I can find them cheapish.
   
  I've since had other people listen to the new sound from my Essence One and they have all agreed that there is far lass bass and punchiness, however they all mentioned that the soundstage improved and there was more details in the trebles. But overall the concessus was that the stock op amps sounded better.
   
  I'd put them back in but not sure they will work as the legs got pretty bent when I took them out. They might work if I bend the legs back but I think one of the legs looks too damaged and I don't want to run the risk of blowing the E1


----------



## alfa147x

Quick question. How do you know if OpAmps are interchangeable?


----------



## Mad Max

They are easily interchangeable when they are in sockets.
  You can find photos depicting examples throughout this thread, iBasso threads (excluding the ones dealing with iBasso's slim amps), Zero DAC threads, Audio-gd threads dealing with the FUN, Sparrow, and Compass, fi.Quest threads, and more.


----------



## ecohifi

Hi Mad Max, you're right about the ADA 4610-2BRZ.   Very musical, cant live without them, they are more forward and the microdetails are easier to hear than the ADA 4627-1BRZ.  I even think the bass is more emphasised!  Great opamp that is well compensated internally and is more stable.
   
  Again, thnxs and well done Mad Max!!!


----------



## ecohifi

Quote: 





alfa147x said:


> Quick question. How do you know if OpAmps are interchangeable?


 

 Always download the datasheets from the manufacturer and compare pin configuration and compatibility.  You cannot swapt Opamps at will.
  Check for supply voltage compatibility, what it is designed for and whether it is suited for audio.


----------



## PurpleAngel

Quote: 





alfa147x said:


> Quick question. How do you know if Op-Amps are interchangeable?


 
  We were hopeful that you would do a lot of op-amp rolling (swapping) and tell us.


----------



## alfa147x

Thanks. Working on building my first amp right now. Figured I would find a opamp to use then build everything around it. 
  Currently thinking about going with dual OPA627 / OPA637 but want to find a cheaper alternative to build with.


----------



## ecohifi

Quote: 





alfa147x said:


> Thanks. Working on building my first amp right now. Figured I would find a opamp to use then build everything around it.
> Currently thinking about going with dual OPA627 / OPA637 but want to find a cheaper alternative to build with.


 


 There are better opamps than the OPA627/OPA637, If youre heading the OPA route I suggest the OPA827/OPA1611/OPA1641, I have never liked the OPA627, its expensive and disappointingly veiled!!!
  I preferred the AD any day, way ahead in transparency of any OPA,  OPA are so Brown Burr!!!!


----------



## sssboa

Quote: 





ecohifi said:


> There are better opamps than the OPA627/OPA637, If youre heading the OPA route I suggest the OPA827/OPA1611/OPA1641, I have never liked the OPA627, its expensive and disappointingly veiled!!!
> I preferred the AD any day, way ahead in transparency of any OPA,  OPA are so Brown Burr!!!!


 

 Yeah, actually I would prefer anything to opa627, like any stock NEC etc.
  BTW, do you know maybe something from AD maybe not that is even more than LM4562  ?  More airy, transparent, detailed, towards wider soundstage? Neutral or on the bright side and I like slightly recessed mids!


----------



## alfa147x

Thanks for the suggestion. I'll be going with the OPA827 instead.


----------



## Mad Max

Quote: 





sssboa said:


> Yeah, actually I would prefer anything to opa627, like any stock NEC etc.
> BTW, do you know maybe something from AD maybe not that is even more than LM4562  ?  More airy, transparent, detailed, towards wider soundstage? Neutral or on the bright side and I like slightly recessed mids!


 

 OPA827 without bypass caps tends to give the kind of sound that you are asking for.


----------



## dumbears

ADA4610 is the newest candidate here.  Before then, I saw OPA1662 introduced some discussions.  Which is better in terms of different music genres?
   
  Pls advise.  Thanks in advance.


----------



## Mad Max

4610 has a deeper soundstage and is more neutral, so I would say it would be better for classical, jazz, acoustic, and electronic.  OPA1662 is warmer, rather red-orange in sound, and more intimate, so better for other kinds of music, small ensembles and stuff, I suppose.


----------



## EraserXIV

Any recommendations for a tubey opamp with liquid and sweet mids? Somewhat weighty low-end would be nice too.
   
  For use in an M-Stage, looked into the LME49990, any thoughts?


----------



## Mad Max

I suppose OPA827's mids sound pretty "liquid", or OPA1602.  But not sweet.  I would replace the electrolytics before the opamp with Elna ROA "Cerafine" caps of equivalent value for that sweetness.  "Tubey"?  Closest thing would be OPA Moon going by what others say, but its bass sucks and has roll-off.


----------



## SpudHarris

any love for OPA1662? Amazing low end and imaging in my set up. Not sure if you'd class it as tubey but I guess results will vary dependant on circuit. It's a must have in anyones collection either way.


----------



## ecohifi

Hi Mad Max,
  If you have a set of LME 49720 or LME 49710 and have been listening to the ADA 4610-2brz can you swiched them to the LMEs and tell me what you think?  In my circuit I think the LME are more detailed in the microdynamic area and brings the midrange back into the sound stage.  The LME has resolution in the bass where the ADA 4610-2brz are wider in soundstage, more focus on voices and lack the ability to emphasize the micrdetails.
   
  Looking foward in yours or anyone else that can conduct this experiment


----------



## madwolf

LME49720 (Metal can) has more authority. More RAW if you can guess what I mean. 
  Deeper bass. but the high is a bit sibilant and slighting piercing. 
   
  AD4610-2BRZ is more polite. More Details, layering, seperation is clearly better. 
  It is slightly smoother. 
   
  LME49720 is better for Rock and Guitar, 4610 is better for Classical
   
  Tested by just changing the OP-AMP nothing else change. Volume un touch.


----------



## Tommy Thong

Quote: 





spudharris said:


> any love for OPA1662? Amazing low end and imaging in my set up. Not sure if you'd class it as tubey but I guess results will vary dependant on circuit. It's a must have in anyones collection either way.


 
   
  I'm still using them on my cd player.
	

	
	
		
		

		
		
	


	




Also, i used OPA1662 and BUF634 as on The Wire Headphones Amp set-up, the sound is so good


----------



## SpudHarris

Nice one Tommy...
   
  I'm using them still in my PB-2 and P4, I think the low end is the most impressive I have heard. Not boomy, just tight and deep, man I love these opamps.


----------



## proton56

Hi everyone


I read this forum for a long time, I have never post anything because my english is so poor...
Thank you for all the informations.

I have use the 4562 for a long time (it is the same as the lme49720).
the metal can is better, I confirm.

The details are very good, but it lack of life, the high are pro-eminent and the voices are not so good, it's boring after a long time.
They have to be combined with more 'musical' opa or amp to be good.
All the LME have the same kind of defaults, if you like this kind of sound you should tried:
 - LME49725, LME49722 I prefer them over the 49720, they are even more detailed,
 - LME49713, is more natural, very fast and powerful, but it can oscillate, (cfa amp / 1.2kR feedback resistor necessary) it can be a good headphone amp (for high efficiency headphone)
 - LME49990 is the more detailed, it can be harsh, but I like it.

The 4610 have the same kind of sound than 4627, 827 and 627, it's coloured like a valve amp !
The 4610 and 4627 are the kind of this type of sound, they are detailed, with a large scene, it's not me cup of tea, but sometime it can be good...


My preferred are : opa2211 (highs a little metallics), ada797 (grainy sound), op1662 (equilibrate, with a good energy, but not very detailed), opa1612 (too sweet; forgiving, and a good "foot tape factor").

And for the Jfet (it's less good) : opa2142, opa1642 (the highs are not naturals), ada4610, ada8620....


Good listening

Proton


----------



## formula1

Do you guys notice the difference between A and B track? 
http://bursonaudioblog.blogspot.com/2012/02/marantz-cd72-hd-opamp-mod-with-sample.html
   
  Been considering to mod my CDP with their opamps. 
  Thanks.


----------



## Tommy Thong

Quote: 





formula1 said:


> Do you guys notice the difference between A and B track?
> http://bursonaudioblog.blogspot.com/2012/02/marantz-cd72-hd-opamp-mod-with-sample.html
> 
> Been considering to mod my CDP with their opamps.
> Thanks.


 
   
  Yes, but did you compare the price difference?(its "under $10-20" and "$160" /pair), For my opinion n taste, if i can do opamp ic rolling for under $20/pair, i'll do it for my $200 cd player but for $160/ pair burson opamp, hell no 
	

	
	
		
		

		
		
	


	



  Otherwise, i still using my Goldmund stuff (36 cd player,12 DAC, 22 pre-amp, and a pair 29.4 amp), its away better sound than burson


----------



## proton56

hi

Burson are coloured, characteristics are bad (distortion ...), some guy like this, but not me.
Definition is bad, it's veiled, all the instruments have the same sound, after a long time it's boring.

You can try it, it's a lot of money but you can like it.


----------



## DefQon

What is the roundup for the best opamps for different genres one could buy today?


----------



## Tommy Thong

Quote: 





defqon said:


> What is the roundup for the best opamps for different genres one could buy today?


 
   
  depend on your taste n you need to roll it yourself, these are the choice:
  - LME49990 is neutral n nice
  - LT1122 is more microdetails n crips
  - OPA1662 is so sweet on mids n vocals, nice tight bass


----------



## SpudHarris

Quote: 





tommy thong said:


> depend on your taste n you need to roll it yourself, these are the choice:
> - LME49990 is neutral n nice
> - LT1122 is more microdetails n crips
> - OPA1662 is so sweet on mids n vocals, nice tight bass


 
   
  That's exactly right!!
   
  Personally I also like OPA602BP (CM in my EF-5), neutral but nice detail. kind of between the 49990 and LT1122. Also, I like ADA4610-2-BRZ, these are very nice indeed and great match with my musical taste (Shpongle - Younger Brother - Aes Dana - Asura - Sergio Walgood - Astropilot etc...etc...)


----------



## Mad Max

Quote: 





ecohifi said:


> Hi Mad Max,
> If you have a set of LME 49720 or LME 49710 and have been listening to the ADA 4610-2brz can you swiched them to the LMEs and tell me what you think?  In my circuit I think the LME are more detailed in the microdynamic area and brings the midrange back into the sound stage.  The LME has resolution in the bass where the ADA 4610-2brz are wider in soundstage, more focus on voices and lack the ability to emphasize the micrdetails.
> 
> Looking foward in yours or anyone else that can conduct this experiment


 
   
  Actually, 4610 just sucks at microdynamics versus all the others I have, lol!  I wonder why.  I somehow overlooked this.


----------



## ecohifi

Quote: 





mad max said:


> Actually, 4610 just sucks at microdynamics versus all the others I have, lol!  I wonder why.  I somehow overlooked this.


 
   
  So you actually did what I requested on a previous post and discovered what I found or are you just joking???
	

	
	
		
		

		
		
	


	



  The microdetails are somewhat compressed and not so emphasis compared to the LME 49720.  Im going to listen to these for a while and then change to the ADA 4627-1brz


----------



## Mad Max

Not microdetails, the dynamics.  I do not hear a difference in microdetail retrieval.
  ADA4627 also beats 4610 with dynamics.


----------



## Mutsu

I just received 4x AD797BR which I've just tried in numerous positions in my Essence one.
   
  I was previously running with stock op amps but with 1x 49720HA in the buffer slot and found the sound stage to be much wider, but lost a lot of bass also.
   
  First I tried 1x AD797BR in the Buffer slot (Replacing the 49720HA) which overall sounded quite nice and lead me to try 1x AD797BR in the Buffer slot and 2x AD797BR in the Low Pass Filter slots. With this I found bass had returned, but sound stage was reduced slightly and more annoyingly the vocals seemed slightly veiled compared to before, like they had taken a bit of a back seat now.
   
  Lastly I tried keeping the 2x AD797BR in the Low Pass Filter Slots and putting the 49720HA back in the buffer slot. Instantly I noticed that sound stage had returned and mostly I was happy with the sound, yet after further listening I noticed that vocals still sounded slightly veiled and bass is less punchy/impactful than required in certain songs. Some songs also felt very slightly 'fuzzy' sounding, like there was a bit of background noise within some parts of the music.
   
  Now I've still not tried replacing the 4x I/V op amps and think that's probably what I should try next.
   
  Based on the above, does anyone have any advice as to what I should try next?


----------



## PurpleAngel

Quote: 





mutsu said:


> I just received 4x AD797BR which I've just tried in numerous positions in my Essence one.
> I was previously running with stock op amps but with 1x 49720HA in the buffer slot and found the sound stage to be much wider, but lost a lot of bass also.
> First I tried 1x AD797BR in the Buffer slot (Replacing the 49720HA) which overall sounded quite nice and lead me to try 1x AD797BR in the Buffer slot and 2x AD797BR in the Low Pass Filter slots. With this I found bass had returned, but sound stage was reduced slightly and more annoyingly the vocals seemed slightly veiled compared to before, like they had taken a bit of a back seat now.
> Lastly I tried keeping the 2x AD797BR in the Low Pass Filter Slots and putting the 49720HA back in the buffer slot. Instantly I noticed that sound stage had returned and mostly I was happy with the sound, yet after further listening I noticed that vocals still sounded slightly veiled and bass is less punchy/impactful than required in certain songs. Some songs also felt very slightly 'fuzzy' sounding, like there was a bit of background noise within some parts of the music.
> ...


 
  Try replacing the LME49720 with LME49860NA, they are the same op-amp, but the LME49860 has a better voltage range.


----------



## SpudHarris

Been tracking back to opamps I personally never really took to but that seem to get decent press. At the time I prefered the ADA4637BRZ over the 4627BRZ but Mad Max keeps refering back to the 27's so I'm going to give them a serious listen over a prolonged period and see what gives. Using 4 off in my balanced PB-2 with HA5002 buffers and have to say they are very nice. I'm not going to compare with anything at this stage, I'm just going to try and enjoy them.
   
  Mad Max - I have put an envelope in todays post for you  Do you bypass your ADA4627's? I have a few different caps here so should have something to suit if you think they benefit. I'm liking them a lot as they are!


----------



## zilch0md

Hi!
   
  In Headphonia's review of the iBasso PB2, Mike (the article's author) wrote the following:
   
  Quote: 





> If you want a more transparent sound and better texture on the bass areas, take out the buffer section and go with a dummy buffer.
> 
> 
> No buffer – Limited current, but still good for HD650, sound is cleaner and more transparent to the actual signature of the op-amp.


 
   
*Can anyone explain why current goes down (undesirable) but transparency goes up (desirable) when you replace the buffers with the dummy buffers that iBasso provides?  *
   
  How much loss of power would you guess is suffered for the sake of an increase in transparency?  (Expressed in dB or %, your choice...)  
   
  Does this hold true for most amps of similar design or is this just something he is observing with the PB2?
   
  Thanks!
   
  Mike


----------



## Mad Max

Quote: 





mutsu said:


> I just received 4x AD797BR which I've just tried in numerous positions in my Essence one.
> 
> I was previously running with stock op amps but with 1x 49720HA in the buffer slot and found the sound stage to be much wider, but lost a lot of bass also.
> 
> ...


 
   
  BUF634 for buffer.  It's a buffer opamp, lol.  I think you will love it more than any other chip in buffer.
   
  Try OPA827 in I/V.


----------



## Mad Max

Quote: 





spudharris said:


> Been tracking back to opamps I personally never really took to but that seem to get decent press. At the time I prefered the ADA4637BRZ over the 4627BRZ but Mad Max keeps refering back to the 27's so I'm going to give them a serious listen over a prolonged period and see what gives. Using 4 off in my balanced PB-2 with HA5002 buffers and have to say they are very nice. I'm not going to compare with anything at this stage, I'm just going to try and enjoy them.
> 
> Mad Max - I have put an envelope in todays post for you  Do you bypass your ADA4627's? I have a few different caps here so should have something to suit if you think they benefit. I'm liking them a lot as they are!


 
   
  Because it is still my numero uno.  ADA4610-2B would take its place, but it sucks at dynamics for some reason.  C'est la vie, heh heh.
  Still got some ceramic cap and a Vishay ERO MKP1837 film cap on its power supplies.  I ran out of tantalums or I would have put one on 4627.
   
   
  Quote: 





zilch0md said:


> Hi!
> 
> In Headphonia's review of the iBasso PB2, Mike (the article's author) wrote the following:
> 
> ...


 

 Less stuff in the signal path (very desirable)?


----------



## zilch0md

Quote: 





mad max said:


> Less stuff in the signal path (very desirable)?


 
   
  I'm with you, but then what's the purpose of a buffer?  Why is everyone rolling buffers in the PB2 in addition to rolling op-amps?  
   
  Surely they don't want less transparency, less detail, and/or more noise, so there must be a big loss of power that goes with replacing the buffers with dummy buffers.  
   
*In other words, can somebody help me understand why I don't want to just leave the dummy buffers in my PB2 permanently?*
   
  Thanks,
   
  Mike
  (Ignorant yet unwilling to ignore this mystery.)


----------



## Mad Max

Probably also depends on how sensitive your headphones/earphones are.
  So you notice this even with LCD-2?  SE530 and HD280 are very, very efficient.


----------



## Mutsu

Quote: 





mad max said:


> BUF634 for buffer.  It's a buffer opamp, lol.  I think you will love it more than any other chip in buffer.
> 
> Try OPA827 in I/V.


 
   
  I forgot to mention my primary listening setup is through my speakers currently, would you still recommend trying the BUF634 in buffer and OPA827? Or would there be something better suited for headphones?
   
  Thanks


----------



## Mad Max

Yup.  Only thing better than BUF634 in buffer is _two_ BUF634 stacked on top of each other, lol!  But you would need to solder them together.


----------



## SpudHarris

Or buy the stackable ones from ibasso.....


----------



## Tommy Thong

Quote: 





spudharris said:


> That's exactly right!!
> 
> Personally I also like OPA602BP (CM in my EF-5), neutral but nice detail. kind of between the 49990 and LT1122. Also, I like ADA4610-2-BRZ, these are very nice indeed and great match with my musical taste (Shpongle - Younger Brother - Aes Dana - Asura - Sergio Walgood - Astropilot etc...etc...)


 
  Perfect...i tried opa602bp n buf634 as headphones amp on protoboard lastnight..love it!!!
	

	
	
		
		

		
		
	


	



  where did you buy opa602cm?/is it obsolute chips,right?any extra?
  i dont try ada4610-1brz  that's much


----------



## Mad Max

qusp, (if you're still alive, lol) is it true that high speed opamps need to have their power supply high-frequency noise/junk/whatever sent to ground via high-frequency decoupling caps? That would explain a thing or two.
  Edit: True
   
  Oh, and 100-ohm dampening resistors before AD797's pins 2 & 3.
 HURRRRRRRRR this is why we are a load of retards with overheating 797s.


----------



## zilch0md

Hi Mad Max,
   
  Quote: 





mad max said:


> Probably also depends on how sensitive your headphones/earphones are.
> So you notice this even with LCD-2?  SE530 and HD280 are very, very efficient.


 
   
  This had to be directed at me, as I own the LCD-2, SE530, and HD280, but I can't figure out what you're asking me.  
	

	
	
		
		

		
		
	


	



   
  I don't know what it is that you're wondering if I've noticed with the LCD-2.
   
  Here's the post you followed:  http://www.head-fi.org/t/432749/the-opamp-thread/3810#post_8349405
   
  Thanks!
   
  Mike


----------



## zilch0md

Quote: 





mad max said:


> ... this is why we are a load of retards with overheating 797s.


 
   
  Yeah!  Tell me about it!  I'm the biggest retard of all - I don't even want to roll my opamps until I have some clue of what I'm doing...  It's my brain that's overheating.  
   
  Lots of questions - no answers.   I should have bought an SR-71B with soldered-in op-amps instead of a PB2.


----------



## Mad Max

Quote: 





zilch0md said:


> Hi Mad Max,
> 
> 
> This had to be directed at me, as I own the LCD-2, SE530, and HD280, but I can't figure out what you're asking me.
> ...


 
   
  So even with LCD-2, you notice an improvement in transparency with dummy buffers?
  I would expect for you to notice such an improvement with HD280 and SE530 due to how sensitive they are, but I figured that your ortho would sound better with (non-dummy) buffers.


----------



## SpudHarris

You are right Mad Max. I've tried it for myself.... ES5 and W4 are nicer (slightly) with dummy adapters in buffer position. LCD-2 sounds ok with this but much better with stacked BUF634 or even better with HA5002 buffers.
   
  The PB-2 does agreat job with full sized cans but it's still not as nice as the EF-5 but it's portable. If you want an amp that is flexible enough to use with IEM's on the go and full sized cans at home you need to look at the Fi-Q, this is an amazing amp in both scenarios... + you can ROLL - Yay!!


----------



## zilch0md

Mad Max,
   
  I've only had the PB2 five days, now, and have yet to do any rolling. So, I've not tried running it with the dummy buffers (nor anything other than the stock configuration - OPA604's with with BUF634's - as shipped from iBasso).  I haven't even tried changing the gain jumpers yet - they're still at the default medium-gain position.  
   
  This must beg the question, "What are you waiting for?"   Answer:  I'm waiting for balanced Silver Poison cables for my LCD-2 that just shipped out yesterday from the UK (by Frank at Toxic Cables).   I doubt I will ever want to go back to the stock, single-ended Audez'e cables on the PB2, so I'm trying to get as familiar as possible with the sound of the stock PB2 > single-ended > LCD-2 (without making any changes to it), so that I can more readily appreciate the difference made by going to the balanced cables when they get here.
   
  Meanwhile, I've been doing a lot of reading about rolling op-amps - just trying to learn stuff before I start rolling with the balanced cables.
   
  All that said, I hear you - it's more likely that I could hear an improvement in transparency (had by using dummy buffers) when single-ended into SE530 or HD280 (because they are sensitive) than single-ended into the less efficient LCD-2.
   
  I'm nevertheless having a hard time finding any resource that can verify Headphonia Mike's suggestion that output current drops while transparency improves by using the dummy buffers. I'd like to know how bad the current loss is by running without buffers, and whether or not there are any other benefits or pitfalls to doing so.
   
  Thanks!
   
  Mike


----------



## Mad Max

The drop is big, most opamps pump out 20-50ma of current while BUF634 pumps out 250ma.  That's 250ma in addition to OPA604 (35ma).


----------



## zilch0md

Quote: 





mad max said:


> The drop is big, most opamps pump out 20-50ma of current while BUF634 pumps out 250ma.  That's 250ma in addition to OPA604 (35ma).


 
   
  That's huge!  I've read that LCD-2 wants current more than voltage, so going by your statement, here, it seems the LAST thing I'd want to do is cripple my PB2 by running it with dummy buffers!
   
  So... Here's a theory question:   Can we say that the purpose of "buffers" is to increase the current coming from the source device while the role of the "op-amp" is to increase the voltage?  
   
  (I know that buffers can themselves be op-amps, but I think you'll get the idea of my question...)
   
  Thanks Mad Max!
   
  Mike


----------



## Mad Max

Something like that, I suppose.  =]


----------



## Mutsu

Can anyone give opinions of BUF634 used as an RCA -> AMP -> Speakers  setup?


----------



## WiR3D

Hello boys and girls, and ROBSCIX, leeperry and SpudHarris.
   
  I was reading about 30 pages of your guys posts from "09  (after I bought the opamps unfortunately)
  I'm on a quest to smoothen out a common problem with the STX, namely the harshness and bloated bass. This is especially a problem with the Denon D2000.
   
  So I went and bought:
  LT1057, AD797BR, OPA827AID, 2xLME49710HA and THS4032.
  And wow bigger differences then I could have ever thought, I was worried the harshness was tied into the TI HP amp built into the STX, and since I am only rolling I/V opamps it limits things.
   
  Anyway I thought I would throw back my feedback:
  (Using MusicBee with Wasapi, 24bit/44.1kHz output and testing with the AKG K242HD for now, since its more analytical, makes it easier to spot differences.)
   
 [size=medium]*AKG K242HD*[/size]

 JRC2114D
 *SS*:harsh, dynamic, crisp, bassy
 *Bass*:muddy and bloated
 *Mids*: perfect
 *Highs*: harsh
 *Soundstage*: Big (naturally) with accurate imaging but not neccissarily great,
 *Speed*: medium, slow with bass
 *clarity test*: 8/10
 *Listening time*: 35min at most

 AD797BR
 *SS*: HARSHER!!!! very dynamic, very tight, unbelievable clarity, airy


 NO resonances or natural overtones, ultra crisp.
 I can see why they are one of the best, but definately not the nicest to listen to in this application.
 has some burn in time, harshness drops a bit.
 I can literally hear a musicians spit as he plays the sax


 *Bass*: tight, balanced, has it when its needed, but isn't emphasized
 *Mids*: overly tight, sharp
 *Highs*: extremely tight, way way way to sharp, and more painfully harsh then the JRC
 *Soundstage*: Big (naturally), bigger then JRC, great imaging
 *Speed*: very fast - contributes to tightness and over sharpness
 *clarity test*: 11/10
 *Listening time*: 15 min

 LT1057ANC8
 *SS*: naturaly Smooth and tight, loses some detail due to not being as dynamic, slightly oldschool feal?

 Does not like medium or low quality files (256kb mp3 and lower)

 reveals clipping issues and artifacts in MP3s(subpar files) very easily
 not good to pair with analytical phones

 Naturally smooth (doesnt artificially smoothen or sharpen), also it doesn't tame naturally harsh recordings
 wonderful resonances especially on the entire drum kit
 warm and cold: as need be
 very good at detail retrieval
 After burn in becomes much more involving
 a bit of noise.

 *Bass*: not overpowering, tight with good impact, maybe a bit slow, and distorts easily?
 *Mids*: perfect balance, but resonates like hell
 *Highs*: smooth and tight, pleasant
 *Soundstage*: medium, smaller then the JRC, good imaging
 *Speed*: fast but appears slow due to slight lack of dynamics
 *clarity test*: 6/10
 *Listening time*: 300min+ depending on songs, avoiding dynamic complex songs.

 THS4032 - perfect for AKG K242hd
 *SS*: Smooth, tight, very dynamic, very detailed, intimate, warm and bright

 Matches the JRC clarity, without bloating the bass and without being harsh.
 treble can be a bit much
 forgiving - doesn't clip

 *Bass*: impactful, good extension, not overpowering, textured well
 *Mids*: weighty, and slightly forward (prefect for akg k242hd) 
 *Highs*: crystal clear, bright, emphasizes by the same amount as the denons naturally, crisp but not harsh.
 *Soundstage*: large (naturally), slightly smaller then the JRC, GREAT imaging, best out of them all
 *Speed*: fast
 *clarity test*: 10/10
 *Listening time*: 130min+ depending on songs, avoiding very bright songs

 OPA827
 *SS*: very warm, bassy, bright, lacks dynamics, slightly harsh

 more dynamic then LT1057, but way less then THS4032 and AD797BR
 Brighter then THS4032
 same amount of bass as JRC2114, and arguably same quality
 artificial feeling? voices aren't intimate (can be on the odd occasion)
 slightly sibilant in its over brightness.
 mids are strange.

 *Bass*: very textured, boosted by same amount as JRC

 Subbass in spades, muddied a bit

 *Mids*: natural sounding, if not a bit flat
 *Highs*: Overly bright, fatiguing, slightly harsh.
 *Soundstage*: medium-large (slightly artificial sounding) smaller then the JRC,  imaging is good, nothing special 
 *Speed*: slightly slow
 *Clarity test*: 6.5/10
 *Listening time*: 35min

 2xLME49710HA (yes i did make it fit, was the off-height twin leaning towers of piza)
 *SS*: Tight, difficult to discribe, accurate, slightly warm, medium dynamics

 feels slightly warm, but sound is slightly disengaging
 more dynamic then OPA827, LT1057, but less than THS4032 and AD797BR
 smooth, crisp, can be harsh if the song is.
 can get fatiguing

 *Bass*: tight, smooth, probably the nicest out of them all
 *Mids*: seems a bit recessed, disengaging
 *Highs*: neutral
 *Soundstage*: Big (slightly artificially) with good imaging
 *Speed*: fast
 *Clarity test*: 7.5/10
 *Listening time*: 180min+ (with a few breaks)

   
  I'm busy trying to fix a faux impedance decreasing adapter, since v1 has some crosstalk issues, before I test with the D2k, because the impedance mismatch makes it too bright, and too bassy.
   
   
   
  Unfortunately now i want to test:
  OPA132UA, LT1364CN8 (Is it worth going for the LT1363 in an adapter?), LT1208CN8, LT1122, LME49990
  and I'm broke after paying $700 to fix my Honda Blackbird.... sigh... And just as a side note I am after balance and smoothness, and as much clarity as I can get with that. So far the THS4032 is the winner, but I have a feeling the LT1364 will take the spot


----------



## Pluto2

My 4627 gets quite hot...must be oscillation....
  What would be good bypass caps for them? And how? I lost track on this....
  I have two on an adaptor, up and down,,,,do I need to by pass both chips?
  Thanks guys!


----------



## Mad Max

0.1uF ceramic on each chip across pins 4 and 7.
  Then a 10uF tantalum on the adapter.  I tried adding the film cap on the top of the adapter and only one chip seemed to benefit, so add it under the adapter board instead.
  The tantalum is polar, so make sure that the negative end connects to pin 4 of the adapter, positive to pin 8.  I've never tried adding it backwards, I assume it will kill the cap and/or your opamps.


----------



## FritzS

My experience with some OPA's
http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit/750
  
  [size=small]currently I like the OPA627[/size]


----------



## ecohifi

Hi Guys,
   
  The opamp marked U1090 has the print: 0828C, 16M and AP 55 G4( or Q4), can someone identify this opamp????
   
  Regards
   
  ecohifi


----------



## Avro_Arrow

Here you go.


----------



## Mad Max

That definitely looks like TL082.  TLE2082 is supposed to be a direct upgrade from it.


----------



## ecohifi

Quote: 





avro_arrow said:


> Here you go.


 
   
   


mad max said:


> That definitely looks like TL082.  TLE2082 is supposed to be a direct upgrade from it.


 
  Thank you very guys that was brilliant,  do you think that would be the later TLE 2082 as the TL082 is not made?  The DAC was made less than a month and it has LME 49990 in a XLR mode for balance?
   
   
  Regards
   
  Ecohifi


----------



## Avro_Arrow

Nope, that's a TL082BC.
   
  The is no "BC" version for the TL2082
   
  Quote: 





ecohifi said:


> Thank you very guys that was brilliant,  do you think that would be the later TLE 2082 as the TL082 is not made?  The DAC was made less than a month and it has LME 49990 in a XLR mode for balance?
> 
> 
> Regards
> ...


----------



## ecohifi

Quote: 





avro_arrow said:


> Nope, that's a TL082BC.
> 
> The is no "BC" version for the TL2082


 
   
  Good one Avro_Arrow, 
   
  NAD must have had excess stock and are now using them to put in there latest Master Series DAC and Digital Amplifiers such as the M2 and 390D.   Its actually used to convert the XLR arrangement of the LME 49990 to single RCA!
  The TL082BC is no longer available in most SOIC version nor are they available in PDIP, http://www.ti.com/product/tl082b
   
  Love your quote bro, the things we do to get the best Audio goodness!


----------



## danny93

Hey guys...I just got myself some Ultrasone PRO900 and was wondering what opamps would pair nicely with it, I use a Titanium HD 
   
  ATM I have:
   
  OPA2134, OPA2111KP, LME49720NA ,AD797ANZ, LME49710
   
  Would any of these be good for buffers or I/V?
   
  Something that would bring out the mids a little would be good, and perhaps tame the highs...I hear they are rather bright cans 
   
  Thanks


----------



## FritzS

look for LME49713HA
  Output Current  RL = 150Ω, VS = ±18V ±100 mA, ±91 mA (min)


----------



## ecclesand

Quote: 





mad max said:


> 0.1uF ceramic on each chip across pins 4 and 7.
> Then a 10uF tantalum on the adapter.  I tried adding the film cap on the top of the adapter and only one chip seemed to benefit, so add it under the adapter board instead.
> The tantalum is polar, so make sure that the negative end connects to pin 4 of the adapter, positive to pin 8.  I've never tried adding it backwards, I assume it will kill the cap and/or your opamps.


 
   
  Does that also apply to dual channel opamps?


----------



## danny93

Quote: 





fritzs said:


> look for LME49713HA
> Output Current  RL = 150Ω, VS = ±18V ±100 mA, ±91 mA (min)


 
  What would this have good synergy with...anything I listed I had?
   
  Cheers mate


----------



## Mad Max

Quote: 





ecclesand said:


> Does that also apply to dual channel opamps?


 
   
  Of course.  Notice that the power supplies are pins 4 & 8 on a dual chip or 2x1 adapter.  4 & 7 on a single chip.
  If you drop an opamp into some circuit and you won't be rolling it, then it is supposed to be a little better to bypass each power pin with one cap each (or any additional caps in parallel), with the other end of the cap(s) connecting to ground (not any floating ground).  But this is also supposed to depend on the quality of the ground, whatever that means.  =p


----------



## ecclesand

mad max said:


> Quote:
> 
> 
> 
> ...




Ah...I see...as long as the cap leads are connected to the V+ and V- it doesn't matter if single or dual. Thanks!


----------



## ecohifi

Quote: 





fritzs said:


> look for LME49713HA
> Output Current  RL = 150Ω, VS = ±18V ±100 mA, ±91 mA (min)


 
  LME 49713 has a rediculous high slew rate, has anyone experience any instability issues especially when used for unity gain?


----------



## proton56

Yes,

It's it have oscillate in my set-up (strong noises), you have to install a 1.2k resistance between the pin 6 and 2 (see the data sheet p10)
and even with that, I suspect something wrong (very hight frequencies ?).

I have no oscilloscope, and I have stopped to use it.

The sound is good, better than lme49710, but not better than lme49990.

I prefer opa2211,1612, ada797 etc...

Generally I appreciate very low thd and good slew rate, I don't think it's ridiculous.
(like Jim Williams and others).


I suspect amp with low slew rate to be too sweet and can't have a good vibrato and grain with instrument like violin. 

The amp with bad thd are veiled on the hight or coloured.


----------



## proton56

opa2111 is very good for the bass
lme49710 is very good for the highs

opa2111 + lme47910 is a good association, but you can find better

opa2134 is veiled on my set-up

ada797 can oscillate but can be very good for buffers or I/V (Weiss DAC etc..)
neutral / hight definition / very good ss / but grany sound and a little cold for someone


----------



## Mad Max

Quote: 





ecohifi said:


> LME 49713 has a rediculous high slew rate, has anyone experience any instability issues especially when used for unity gain?


 
   
  That chip looks like it is probably very, very finicky.


----------



## zilch0md

Yeah, 1900 V/ms is a crazy high slew rate!
   
  In this comparison I did of the slew rates for the OPA1611 (used in the Stepdance) and the OPA209 (used in the 2Stepdance), both slew rates are high enough to support ultra-sonic frequencies - and we are still only at double-digit slew rates, never mind three- or four-digit slew rates.
   

   
  Mike


----------



## Avro_Arrow

I built a CMoy based on LT1363...it has a stupid fast slew rate and sounds wonderful.


----------



## zilch0md

Quote: 





avro_arrow said:


> I built a CMoy based on LT1363...it has a stupid fast slew rate and sounds wonderful.


 
   
  Nice.  I envy your having the satisfaction of building your own amp.  
   
  Would you say the ultra-sonic (1000 V/ms) slew rate of the LT1363 played a factor in how nice the amp sounded, or just that the high slew rate didn't cause any audible problems?
   
  Thanks,
   
  Mike


----------



## AmarokCZ

*zilch0md*: from diagram you posted above: for 10V and 20kHz you need at least ~2.5V/us to keep rough shape (good looking on scope) of sine-wave. But you need much more (e.g. ten times more) to keep THD low.
  1KV/us is useless if you ask me, but there are many other things that matters more than SR.
   
  In amp that I designed I am using LT1122 (60V/us) which are better than LT1363 in my opinion. Even LT1115 (only 10V/us) sounds great (still better than LT1363 for me). The other amp - electrostatic one - I designed (not using OA) is quite slow (only 25V/us) and still sounds lovely.
   
  So I don't think there is correlation between very high SR and "good sound".


----------



## zilch0md

Thanks for the explanation!


----------



## Avro_Arrow

The slew rate is far in excess of what is needed.
  It was more of a case of "it didn't cause any problems".
  Quote: 





zilch0md said:


> Nice.  I envy your having the satisfaction of building your own amp.
> 
> Would you say the ultra-sonic (1000 V/ms) slew rate of the LT1363 played a factor in how nice the amp sounded, or just that the high slew rate didn't cause any audible problems?
> 
> ...


----------



## SpudHarris

The 1363 never really did it for me even though Leeperry thought it was the best thing since sliced bread at one point. This of course be down to lots of factors like circuit, musical genres, source etc..... The only LT OpAmp to really get me was/is the 1122, I like it a lot.
   
  At the moment I have various OpAmps on the go.
   
  AD797BRZ in my EF-5
  LME49990 in my PB-2
  OPA1662 in my Fi-Q
  THS4032 in my P4
   
  They all sound great for different reasons...


----------



## Avro_Arrow

Yes, I agree...no one op amp is a do all, end all for every situation.
  I have LME49990 in my DAC.


----------



## leeperry

I think the major issue is that most ppl roll opamps blindly and expect miracles.....I think what we need badly is a tutorial including a cheap USB oscilloscope explaining how to ensure that those chips aren't oscillating like hell.
   
  Rolling AD797 or LT1208 blindly is bound to fail, and it will...even TI say so(thanks MadMax for the link!), I guess they'd know 
	

	
	
		
		

		
			





 : http://e2e.ti.com/support/amplifiers/precision_amplifiers/w/design_notes/upgrading-op-amps-in-audio-equipment.aspx  
   
  LME49990 and LT1363 are the exact same story. I will never roll blindly ever again, either I will gain the knowledge to ensure stability or I'll give it up altogether.
   
  Anyway, I've heard stunning DAC's using OPA2132 and OPA627 in their output stage....it's all about their surrounding design as usual. A dual opamp used a LPF out of a voltage output DAC will always sound poor, c'est la vie.


----------



## Mooses9

does anyone have any thoughts or opinions on the LME49990 with the ibasso p4? what are the signatures of this opamp? is it pretty good?.


----------



## Mad Max

Spudharris thinks it's an amazing combination.


----------



## SpudHarris

LOL
   
  And here!


----------



## WiR3D

Quote: 





leeperry said:


> I think the major issue is that most ppl roll opamps blindly and expect miracles.....I think what we need badly is a tutorial including a cheap USB oscilloscope explaining how to ensure that those chips aren't oscillating like hell.
> 
> Rolling AD797 or LT1208 blindly is bound to fail, and it will...even TI say so(thanks MadMax for the link!), I guess they'd know
> 
> ...


 
   
  Gulp.... thats more or less what I have been doing 
	

	
	
		
		

		
		
	


	



   
  well, i read a lot of your early posts in this thread and made a list of opamps to try above my current selection (mainly for the I/V section in my STX.)
   
  I have tried:

 JRC2114D (stock)
 AD797BR
 LT1057ANC8
 THS4032
 OPA827
 2xLME49710HA (it was the twin leaning towers of Piza, but i got it right, wasn't worth the dodgeyness)
   
  And now I want to try:

 OPA132UA
 2xLT1363CN8
 LT1678IS8
 LT1208ACN8
 2xLT1122
 LME49990
 OPA2132P
 AD8599
 OPA627
 OPA1611
   
  Should I avoid any of those for any reason? Ignoring sound Characteristics.


----------



## leeperry

Quote: 





wir3d said:


> Gulp.... thats more or less what I have been doing


 
   
_"You can only get smarter by playing a smarter opponent"._
   
  We'd need to find someone kind enough on diyaudio(Moonly?) or so to explain us how to check for oscillation, and especially how to cure it. Cluelessness has a cure, it's called shared knowledge


----------



## WiR3D

Quote: 





leeperry said:


> _"You can only get smarter by playing a smarter opponent"._
> 
> We'd need to find someone kind enough on diyaudio(Moonly?) or so to explain us how to check for oscillation, and especially how to cure it. Cluelessness has a cure, it's called shared knowledge


 
  is oscillation even audible? if not then whats the problem? or does it generate a kak load of extra heat?


----------



## AmarokCZ

Oscillation itself is very often (almost alvays) inaudible, but it can cause increased hum, THD,... which are audible. It can also cause excessive heating of OA.
  Oscillation can be detected by HF voltmeter.


----------



## WiR3D

Quote: 





amarokcz said:


> Oscillation itself is very often (almost alvays) inaudible, but it can cause increased hum, THD,... which are audible. It can also cause excessive heating of OA.
> Oscillation can be detected by HF voltmeter.


 
  So then how would I detect it? I have a multimeter, but I really don't think that will cut it.


----------



## AmarokCZ

Multimeter is useless, but you can try a HF probe like this and connect it to multimeter, but HF voltmeter (or good scope) has higher sensitivity.


----------



## WiR3D

Quote: 





amarokcz said:


> Multimeter is useless, but you can try a HF probe like this and connect it to multimeter, but HF voltmeter (or good scope) has higher sensitivity.


 
  Yeah I am only starting to get into DIY electronics and tinkering, this is a bit above me for the moment. And a good scope is most probably out of budget.
   
  If its not going to break something, and it sounds good, I will live with it.


----------



## leeperry

Quote: 





wir3d said:


> is oscillation even audible? if not then whats the problem?


 
   
  http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html


----------



## Mad Max

"Page not found."


----------



## Pluto2

Quote: 





mad max said:


> 0.1uF ceramic on each chip across pins 4 and 7.
> Then a 10uF tantalum on the adapter.  I tried adding the film cap on the top of the adapter and only one chip seemed to benefit, so add it under the adapter board instead.
> The tantalum is polar, so make sure that the negative end connects to pin 4 of the adapter, positive to pin 8.  I've never tried adding it backwards, I assume it will kill the cap and/or your opamps.


 
  Thanks!!
  Pardon me, but why tantalum? I thought the material has a strong signature of its own, no?
  I suppose this is a good combination that you have tried : )


----------



## leeperry

Quote: 





mad max said:


> "Page not found."


 
   
  the forum software likes to add spaces at the end of url's for some reason: http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html
   
  Opera is smart enough to ignore them ^^


----------



## Mad Max

Quote: 





pluto2 said:


> Thanks!!
> Pardon me, but why tantalum? I thought the material has a strong signature of its own, no?
> I suppose this is a good combination that you have tried : )


 
   
  Neutral, as far as I can tell.  Kemet ones anyway.


----------



## AmarokCZ

Quote: 





mad max said:


> Neutral, as far as I can tell.  Kemet ones anyway.


 
  Definately not neutral! ... but it doesn't matter when bypassing supply voltage (just like in case of ceramic = best cap for bypassing, but worst when placed in signal path).


----------



## WiR3D

Quote: 





leeperry said:


> http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html


 
  MMM so oscillation = voltage peaks in the opamps. 
  arg how much is a scope anyway? Can someone please post a link to an example? 
   
  As long as the voltage is not being pushed through the headphones it wont be a major problem. It will be fine for now, but I do think my AD797 may be oscillating, owell I took it out anyway to give the OPA827 another shot.


----------



## WiR3D

Just put in the LT1057 again (in my STX + faux impedance decreasing adapter + D7000)... dont flame me yet
   
  my previous impressions with the AKG K242HD were:

 SS: naturaly Smooth and tight, loses some detail due to not being as dynamic, slightly oldschool feal?

 Does not like medium or low quality files (256kb mp3 and lower)

 reveals clipping issues and artifacts in MP3s(subpar files) very easily
 not good to pair with analytical phones

 Naturally smooth (doesnt artificially smoothen or sharpen), also it doesn't tame naturally harsh recordings
 wonderful resonances especially on the entire drum kit
 warm and cold: as need be
 very good at detail retrieval
 After burn in becomes much more involving
 a bit of noise.

 Bass: not overpowering, tight with good impact, maybe a bit slow, and distorts easily?
 Mids: perfect balance, but resonates like hell
 Highs: smooth and tight, pleasant
 Soundstage: medium, smaller then the JRC, good imaging
 Speed: fast but appears slow due to slight lack of dynamics
 clarity test: 6/10
 Listening time: 300min+ depending on songs, avoiding dynamic complex songs.
 
   
   
   
   
  But now... with the Impedance decreasing adapter and the D7000.... just wow

 SS: Smooth, tight, great imaging, euphoric, textured.

 Does the odd strange thing with voices
 lacks some dynamics, easily masked by the strong character of the D7000

 Bass: Textured quite a bit with heavy basslines in a pleasant awesum way, slightly emphasized
 Mids: brings slightly more forward, strange sound sometimes
 Highs: slightly bright, smooth, but not painful
 Soundstage: smaller then normal, better then normal imaging (AD797 still wins)
 Speed: fast as hell
 Clarity Test: 7.5/10, missing some detail, but masks it well
 Listening Time: years.
   
   
  With the D2000 they had something that was difficult to describe, and for a moment I thought I lost that with the D7000, the recessed mids still irk me, but whatever, this combination is just so euphoric... rawr, happy lion


----------



## Mad Max

I tried Kemet R75 caps, and dang, they color the sound.  Clean, refined, very airy, but very white in the mids and treble, yuck.  Fortunately, MKP1837 adds absolutely nothing of its own character, fully neutral while improving your favorite opamps' sound, not even detracting anything.


----------



## WiR3D

Quote: 





wir3d said:


> MMM so oscillation = voltage peaks in the opamps.
> arg how much is a scope anyway? Can someone please post a link to an example?
> 
> As long as the voltage is not being pushed through the headphones it wont be a major problem. It will be fine for now, but I do think my AD797 may be oscillating, owell I took it out anyway to give the OPA827 another shot.


 

 Scopes are not so cheap, locally anyway. Owell
   
  I was about to spend a fair amount on opamps, and I remember reading something about leeperry using the LT1364 opamps, and worrying about the input bias. Did this end up being a problem?
  Because i just noticed the difference between Bipolar and FET opamps.
   
  gulp...
   
  Because a few of the opamps on my list are bipolar, and AFAIK the stx's stock ones are all FET.


----------



## Mad Max

You usually want to replace FETs with FETs.  Bipolars may work, too, if the input resistors to each channel are very closely matched, as far as I know.  Otherwise, you can get massive DC offset at the output of the amp or DAC you are using it in.
  1364 has way too much speed anyway, so it would be better to go with opamps that will run more stable and hence sound better such as OPA2209, OPA1652, ADA4610-2B, etc.  AD8599 and OPA1612 aren't terribly finicky chips and sound stupendous.
  Well, it all depends on how you use them.
  I'm having loads more fun these days:
   

   
  Bad choices would be like ADA4627-1B, AD797, LT1364, ISL55001, and other opamps with huge bandwidth and lots of slew rate.  They are potentially awesome, I think, but not suited for "blind-rolling", which is all we discuss here, lol.  It's easier, and cheaper, to get OPA827, OPA1641, OPA602, and the ones I mentioned before to sound better.  Audio-gd opamps, too, are pretty well-behaved.  Their stock MKT caps kind of suck (little grey boxes on the sides of the opamp module), better to substitute those caps with ceramics and tantalums for far better sound or Russian K42-Y2 PIO caps.  And all of these cap upgrades are generally pretty inexpensive, best of all.
   
  I made a new OPA1611 module with grounded bypassing using MKP1840 caps - good-bye treble peaks, soundstage boxiness, and upper mids funkiness that I would get before.  Now much improved, but still kind of warm.  I should probably switch to MKP1837.


----------



## zilch0md

Quote: 





mad max said:


>


 
   
  I love this picture, Mad Max!  The back lighting and the way they are arranged make them look like cute little robots!  
	

	
	
		
		

		
			





   Mad Max or Mad Scientist?  Both seem appropriate.
   
  I appreciate the advice you've given, too. 
   
  Thanks,
   
  Mike


----------



## WiR3D

mad max said:


> You usually want to replace FETs with FETs.  Bipolars may work, too, if the input resistors to each channel are very closely matched, as far as I know.  Otherwise, you can get massive DC offset at the output of the amp or DAC you are using it in.
> 1364 has way too much speed anyway, so it would be better to go with opamps that will run more stable and hence sound better such as OPA2209, OPA1652, ADA4610-2B, etc.  AD8599 and OPA1612 aren't terribly finicky chips and sound stupendous.
> Well, it all depends on how you use them.
> I'm having loads more fun these days:
> ...




When I'm on my PC your gonna get a plus one. How are you measuring the fr? Recording the output? 
I was already using the ad797 in my stx, gulp. I'm not exactly using it with sensitive phones though, akg k242hd, and denon dxk with a faux impedance decreasing adapter that chows almost 1w. 

Now those treble peaks, I wouldn't mind killing the treble peaks the ad797 is giving off with the akgs, I have a feeling it could be oscillation. 
So the LT 136x is a bad idea, but the ad8599 is ok? 

Sent from my HTC HD2 using Tapatalk 2


----------



## Mad Max

Yup, checking the output.  Also, the peaks make K701 and A2000X painful to use.
   
  AD8599/8597 seems to be pretty well behaved; perhaps it is very well compensated internally, who knows.
   
  I don't think that you will kill anything with an oscillating, and hence over-heating 797, but for your convenience if you are deciding on what opamps to stick in your gear, it's a good idea to just forget that chip.


----------



## WiR3D

mad max said:


> Yup, checking the output.  Also, the peaks make K701 and A2000X painful to use.
> 
> AD8599/8597 seems to be pretty well behaved; perhaps it is very well compensated internally, who knows.
> 
> I don't think that you will kill anything with an oscillating, and hence over-heating 797, but for your convenience if you are deciding on what opamps to stick in your gear, it's a good idea to just forget that chip.




Thanks a lot I really appreciate the advice. I would forget it, I really would, but you have no idea how awesum it sounds with the AKG K242HD, it's breathtaking, just the treble is a bit much.

I'm gonna change my purchase list a bit.

Now those caps you keep placing across the OpAmps? Where do you get the figures for what is needed? (my electrical knowledge is limited) because that looks like fun

Sent from my HTC HD2 using Tapatalk 2


----------



## ecohifi

Has anyone tried the LME 49880, the jfet version that is PSOP format.  If so, what is your impression and what adapter did you use?


----------



## qusp

nope, but planning to shortly. i'll probably do up a PCB, but here is some suitable adapters. looks like a nice chip. i'm loving national opas these days, with the 49990 rocking my world on the bal-bal 'the wire' on the output of my portable sabre. its a dual so not all that useful for many things I do, but i'm looking to recap and mod some old active KRK monitors I have here and they look like they might fit the bill, gonna try them and the new opa1652 in trhe active crossover/filters
   
  since you likely wont be using reflow soldering to solder them, you'll need to drill a small via in the middle of the powerpad and solder that from underneath; otherwise it'll overheat


----------



## SpudHarris

Quote: 





ecohifi said:


> Has anyone tried the LME 49880, the jfet version that is PSOP format.  If so, what is your impression and what adapter did you use?


 
   
  I got mine here. They are very nice indeed.


----------



## qusp

I prefer the one I linked, it actually has a useful amount of copper linked to the thermal pad, the one above isnt going to sink much heat at all. the connection to the negative rail while not incidental, is secondary


----------



## ecohifi

Quote: 





spudharris said:


> I got mine here. They are very nice indeed.


 
  SpudHarris,
   
  can you recall how hot they ran with the ones you got


----------



## SpudHarris

I can. I had absolutely no issues at all, luke warm in any of my amps. These opamps are hyper detailed but without glare, I guess they are similar to a decent tube amp. the only thing that peeps might find a problem with is the size of the adapter, it's about 25% wider than your normal SOIC pcb......
   
  Just so you know, I bout many modules of LME49990 from the same guy and delivery was always swift, product was genuine, just hassle free!


----------



## zilch0md

Op-amps running hot?   No worries!


----------



## qusp

I guess it'll depend very much on the loading, spud is probably only driving high impedance buffer inputs of the next stage with them, in which case no problem, as the current demands will be very low (thats kinda the point of buffers, to provide a high impedance input, so as to not load the preceding stage and low impedance, sometimes much higher current output so that the load of the next stage is much more benign) but if you are driving the output or even headphones directly, you can have a completely different set of conditions. as pictured, the adapter does not meet the datasheet spec and in high loading conditions it will overheat; thats why its there, the adapter pictured on their site only provides the electrical connection, no heatsinking; some devices need one more than the other


----------



## qusp

Quote: 





> Op-amps running hot?   No worries!


 
   
   
   
  hehe is that an amp in your pocket..or.. ?
   
  nice if you can get the heat to the case instead of being stuck on a tiny little dot


----------



## zilch0md

Hey qusp,
   
  Thanks for all your lucid explanations, by the way!
   
  Quote: 





qusp said:


> hehe is that an amp in your pocket..or.. ?
> 
> nice if you can get the heat to the case instead of being stuck on a tiny little dot


 
   






  Referencing _Blazing Saddles_ - " or... are you just enjoying the show?"
   
  Yeah, I wish there was a way to shunt the heat from the tops of my op-amps and buffers to the aluminum case of the PB2. 
   
  I'm currently running OPA1612 x2 in the L/R, with AD797 x4 as buffers.  This combination is far and away my favorite when running balanced out to LCD-2, but it's also far and away the hottest combination I've tried in the PB2.  (I don't own a scope, so I have no idea if I'm getting any oscillation, but it sure sounds fine.)
   
  I literally have to take the lid off my PB2 to have peace of mind, because _the entire case gets scary warm to the touch_, and if I use the PB2 for an hour or more before taking the lid off, even the battery pack is very warm to the touch before everything cools off.  Nothing except the op-amps themselves get hot when the lid is off, of course.
   
  Heat kills.  What to do?  Putting tiny heat sinks on the chips themselves still leaves the heat trapped inside the case.
   
  I'm thinking of having a professional machinist drill a smartly done array of holes across the entire case - top, bottom, and sides - just to vent it.  It's either that or reach for the thermal epoxy to mount the passive heat sink I pictured!  
	

	
	
		
		

		
		
	


	



   
  Mike


----------



## Mad Max

Add 50V 0.1uF C0G ceramic caps across on the power pins on OPA1612 (example).
  It will probably be a good idea to sell off the AD797s and get AD8597 instead.  Then your amp should run cooler, I think.


----------



## AmarokCZ

Any particular reason for C0G? For bypassing X7R is even better, IMHO.


----------



## qusp

hmm x7r better? there is nothing superior about the x7r spec, it is quite simply lower specced, thats all it means its a tempco (temperature coefficient) grading system. np0/c0g are the highest spec ceramics available in useful values for bypassing anything but RF energy. SMD thin film caps are much better and much more linear too, but dont go anywhere near that high. Np0 stands for negative, positive, zero, meaning within reasonable limits it does not change its behavior/value over temperature, high frequency energy creates heat too, so best have a device that is stable. x7r is the next rung down, still very good, but unless you need a larger value its a worse part for the job, particularly since we are talking about a hot case. you can have your opinion, thats cool, but the manufacturers are not of that opinion.
   
  zilchm0d: no problems on the wordiness, its what I do =). for getting the heat out you could try these and stick a low profile half-brick DC convertor heatsink to the floor or roof. something 'cool' like this enzotech in the 10mm, or go for a 1/4 brick, these are standard sizes for DC-DC convertors so if you cant get the enzotech, you'll be able to find a 1/2 or 1/4 brick from Aavid thermalloy or similar at mouser/digikey.

   
  that being said, you are almost certainly getting instability, the AD797 really isnt all that happy at unity gain unless treated with kid gloves and having them in parallel like that trying to share current too, along with the added lead inductance of doing that; I just dont like your chances at all. this is one of those occasions where the datasheet stretches the truth a bit, yes they are unity gain stable, but its more like  *_unity gain stable_ TM
   
  and yes your electrolytics will be drying out, particularly if they arent 105c rated


----------



## zilch0md

Quote: 





mad max said:


> Add 50V 0.1uF C0G ceramic caps across on the power pins on OPA1612 (example).
> It will probably be a good idea to sell off the AD797s and get AD8597 instead.  Then your amp should run cooler, I think.


 
   
  Thanks very much Mad Max!
   
  I've already ordered a replacement case for the PB2 (top and bottom) from iBasso - in which I plan to drill holes for venting.  I'll keep the original case for resale, if that day comes.
   
  So many questions:  
   
  1) Can you explain why adding bypass caps to the OPA1612s would lower the operating temp?  And why AD8597s run cooler (if that's why you recommended them)?
   
  2)  Would you anticipate any change in SQ with adding the caps -or- replacing AD797s with AD8597s?
   
  3)  Do you think it's OK for me to continue operating with the OPA1612s and AD797s - with the lid off (or with lots of vent holes drilled into the case)?   Am I hurting anything by leaving these components as is, as long as I can get the temperature down?
   
  Again, I am seriously in love with the sound I'm getting currently and would rather not fix that which isn't broken, so to speak.
   
  Thanks!
   
  Mike


----------



## zilch0md

Quote: 





amarokcz said:


> Any particular reason for C0G? For bypassing X7R is even better, IMHO.


 
   
  I have no opinion, either way, but would like to ask, why you prefer X74 vs. C0G?
   
  Thanks!
   
  Mike


----------



## qusp

zilch0md, get yourself a cheap ebay thermal camera, or heat sensor and find out exactly what temp they are running, add some for the thermal impedance of the opamp package to opamp die and check the datasheet for SOA (safe operating area) wrt temp. you can also wire an LED across the output with no signal, if it lights you are getting oscillations. with that heat and considering the far from ideal operating conditions you are running them in, i'm 99% certain you are. if you can get the temp right down, not just of the case, but the opamp die itself, you may not kill the amp, but as is you will be shortening the life of the chips and all of the caps surrounding them. is the amp DC coupled? (no caps on the output) if it is, if they fail open or less than gracefully, you could feed the DC rail voltage directly to the headphones


----------



## AmarokCZ

qusp: nice fairy-tale, but did you even noticed the word "bypassing" in my previous post?
   
  zilch0md: in my experiences few uF of X7R was always better than few hunderds nF of NP0. On the other hand NP0 is superior to other ceramics for timing, filters, RF, microwave,...


----------



## Mad Max

Quote: 





zilch0md said:


> Thanks very much Mad Max!
> 
> I've already ordered a replacement case for the PB2 (top and bottom) from iBasso - in which I plan to drill holes for venting.  I'll keep the original case for resale, if that day comes.
> 
> ...


 
   
  1. They will eliminate oscillations.  Eliminate the oscillations and you will not only get better sound, but the opamps will run lukewarm instead and not shorten the life of your amp with all that darn heat.  AD8597 is an excellent chip, not very finicky, and ADI recommends it over AD797 in newer designs.  797 is a pain in the arse; it's just not a drop-in chip at all.
   
  2.  Yes, only improvement.  You must be careful not to over heat the chips, however.  Take your sweet time when adding the caps across pins 4 & 8 on the chips itself.  If that seems a bit risky to you with your skill level, it would not hurt to add the capacitor to the adapter itself instead.  But I have read datasheets recommending to add the cap as close to the power pins as possible, if not right on them altogether.
   
  3.  Well, you can continue if you want, but why miss out on better sound?  Sell AD797, and the money should be enough for AD8597 and the caps that you need.  A stable AD8597 >>> unstable AD797.  1612 isn't a very finicky chip, either, it seems to me, so a bypass cap should do the trick.


----------



## zilch0md

Quote: 





qusp said:


> zilch0md, get yourself a cheap ebay thermal camera, or heat sensor and find out exactly what temp they are running, add some for the thermal impedance of the opamp package to opamp die and check the datasheet for SOA (safe operating area) wrt temp. you can also wire an LED across the output with no signal, if it lights you are getting oscillations. with that heat and considering the far from ideal operating conditions you are running them in, i'm 99% certain you are. if you can get the temp right down, not just of the case, but the opamp die itself, you may not kill the amp, but as is you will be shortening the life of the chips and all of the caps surrounding them. is the amp DC coupled? (no caps on the output) if it is, if they fail open or less than gracefully, you could feed the DC rail voltage directly to the headphones


 
   
  Good stuff, but I won't blame you for rolling your eyes to this question:  HOW do I "wire an LED across the output, with no signal?"   First, I actually don't know where "the output" is!  
	

	
	
		
		

		
			





  And second, does it matter what kind of LED I use?  
   
  I'm very intrigued by your suggestion because I've been reading up on getting something like a 200Mhz analog oscilloscope, but I keep asking myself what else I'd use it for beyond my little hobby of rolling op-amps occasionally.
   
  So, if this LED approach works, I'm on it.  *Again, what type of LED and where exactly do you place the leads?*
   
  I'm very grateful for the feedback you and Mad Max are giving me!
   
  By the way, I'd never heard of the cool pipe technology - that's amazing stuff.  Do you suppose there's something like acetone inside the copper tubing of that big heat sink I pulled from a Dell server?
   
  Mike


----------



## zilch0md

Quote: 





mad max said:


> 1. They will eliminate oscillations.  Eliminate the oscillations and you will not only get better sound, but the opamps will run lukewarm instead and not shorten the life of your amp with all that darn heat.  AD8597 is an excellent chip, not very finicky, and ADI recommends it over AD797 in newer designs.  797 is a pain in the arse; it's just not a drop-in chip at all.
> 
> 2.  Yes, only improvement.  You must be careful not to over heat the chips, however.  Take your sweet time when adding the caps across pins 4 & 8 on the chips itself.  If that seems a bit risky to you with your skill level, it would not hurt to add the capacitor to the adapter itself instead.  But I have read datasheets recommending to add the cap as close to the power pins as possible, if not right on them altogether.
> 
> 3.  Well, you can continue if you want, but why miss out on better sound?  Sell AD797, and the money should be enough for AD8597 and the caps that you need.  A stable AD8597 >>> unstable AD797.  1612 isn't a very finicky chip, either, it seems to me, so a bypass cap should do the trick.


 
   
  Wow, numbered answers for my numbered questions.  It doesn't get any better than this.  
	

	
	
		
		

		
		
	


	



   
  I can't solder worth a hoot, unfortunately.  You would think that in every big metropolis, it would be easy to find someone who would do soldering "while-u-wait" - paid by the hour, but I guess there's just not enough call for it.  Electronics repair is all about swapping boards, these days, not soldering.
   
  I'll cross that bridge when I come to it.  First, I want to figure out whether or not I'm actually suffering any oscillations - per qusp's LED method (and shop for some AD8597's already soldered to SOIC/DIP adapters, or whatever they are called...)
   
  Thanks again!
   
  Mike


----------



## qusp

LED will tell you DC, you can use an incandescent (if you can still find one) light bulb to check for high frequency oscillations by putting it in series with the power supply leads, but actually now i'm thinking about it I wonder how to use this test with a battery supply and polarity is VERY important here, you will reverse bias the LED and it will not end well. please hold off on this test till I find the document to explain it properly. so for this test disregard the LED, I wasnt thinking clearly, I was thinking of the DC measurement, or placing it in the PSU rail to check for fluctuations in the power draw, it will not help you for measuring AC fluctuations in the output.
   
  do you know if the buffers are running open loop or closed loop in your amp? ie are they wrapped in the feedback loop of the voltage gain stage (the 1612) or do they follow that stage, with only their own local feedback loop? basically you will wire the bulb (small suitably rated incandescent) from left channel or right channel to ground, or if its balanced from the positive to negative phase of one channel. you can leave it as silent with no music but with the volume turned up and if you are getting flickering light you have oscillation. another way would be to calculate what the power consumption of the amp should be into a particular known load, like a 2-5W 100ohm resistor and measure the actual power consumption being drawn from the power supply by measuring the voltage drop across an inline resistor in the PSU rail. that might need more intimate knowledge of the design and electronics knowledge than available to you.
   
  a scope is a great tool and if you are thinking of getting serious it wouldnt be a bad idea at all, but bare in mind there is a significant learning curve involved in learning how to use it properly. you dont absolutely need such a high bandwidth for basic measurements and you dont need the latest and greatest; you could find a good quality 100MHz+ used analogue scope like an Agilent or HP for peanuts now that everyone is moving to digital logging/storage scopes.
   
  shoot me a PM perhaps if you have other questions


----------



## qusp

Quote: 





amarokcz said:


> qusp: nice fairy-tale, but did you even noticed the word "bypassing" in my previous post?
> 
> zilch0md: in my experiences few uF of X7R was always better than few hunderds nF of NP0. On the other hand NP0 is superior to other ceramics for timing, filters, RF, microwave,...


 
   
  erm, hahahahaha yeah fairy tale..... I know very well what 'bypassing' is I would ask you to explain what YOU think it means. I would also ask you to read my post fully, you know, the part where it adds the proviso 'unless you *need* a large value' in which case I would be much more likely to use a polymer, bypassed with np0, or yes perhaps an x7r of 10uf or so depending on the application, supply voltage, available space etc
   
  nothing fairy tale about it, it may disagree with your opinion, but we are talking about a hot case here and we are talking about bypassing high frequency energy, a small higher quality ceramic will do just fine. just what LPF do you think you will get with a few uf and why is it that you think there will be anything to bypass at such a low frequency? for decoupling sure, for bypassing 100nf or 10nf is just fine and for low values where np0/c0g is available, there is simply nothing superior about x7r, its only advantages are *cost* and *higher capacity*, there are no other advantages. if you go too large for a bypass it would be fairly easy to cause resonance with the local decoupling/supply caps, smaller values are much safer in this regard
   
  fine you have some sort of preference here, thats cool, but please do not try to pass it off as fact, I would like you to supply one advantage above the 2 I have supplied above please? across the rails vs each rail to ground is a preference thing as I see it. if you need to add more than a small amount here, the design is flawed
   
  do also remember that the bypass caps on the output stage are directly in the current path for the headphones, some designs and some people will place more importance on this than others.


----------



## qusp

combined above


----------



## AmarokCZ

*qusp*: reading you posts is quite diffucult, please learn to write normal comprehensible sentences like others do or don't expect me spending my time trying to undestand it.
  But anyway, it's no secret that on Head-Fi (and other forums) there are many people who belives in many absurd things, and it's not my job to change their minds. Because it's just like one politician once said: "_It is always more difficult to fight against faith than against knowledge._". So if you want to live in fantasy and belive whatever you want (e.g. that temperature coeffecient does matter for bypass caps or that incades. in series with supply indicates HF oscillations), please know that you have my blessing to belive it!


----------



## kiteki

amarokcz said:


> "_It is always more difficult to fight against faith than against knowledge._".


 
   
  That is a very accurate assessment of audio science.
   
  There's quite a few which refuse to look at anything except for numbers.  Luckily I know this sentiment is not shared by all the high-end developers, even within op-amp's / IC's, for the very simple reason we don't have numbers on _everything. (_<-- the faith usually revolves around this.)


----------



## WiR3D

Quote: 





kiteki said:


> That is a very accurate assessment of audio science.
> 
> There's quite a few which refuse to look at anything except for numbers.  Luckily I know this sentiment is not shared by all the high-end developers, even within op-amp's / IC's, for the very simple reason we don't have numbers on _everything. (_<-- the faith usually revolves around this.)


 
  may be true but I still think he is being rude and obnoxious about it, instead of just explaining his thoughts in a civil manner.


----------



## zilch0md

Quote: 





> Originally Posted by *qusp* /img/forum/go_quote.gif
> 
> [snip]
> 
> ...


 
   
  Unfortunately, I'm clueless as to the design of the PB2.  I'm just a consumer of electronics, but for trying to roll op-amps.  
	

	
	
		
		

		
		
	


	



   
  Thanks for all of your advice, though!
   
  Mike


----------



## SpudHarris

Quote: 





wir3d said:


> may be true but I still think he is being rude and obnoxious about it, instead of just explaining his thoughts in a civil manner.


 
   
  x2
   
  Qusp has been around here a long, long time and has offered many hours of his personal time to help others, this includes me. He is a gent!
   
  It's one thing to have a difference of opinion, I think we all do at some point. But it's a completely different thing to be rude because you can't get the other person to bow to your point of view. I wouldn't blame Qusp for flaming him but I think we should try to get back on track. I know who's opinion I value


----------



## Mad Max

Quote: 





zilch0md said:


> Unfortunately, I'm clueless as to the design of the PB2.  I'm just a consumer of electronics, but for trying to roll op-amps.
> 
> 
> 
> ...


 
   
  iBasso should answer your question.  Ask them if the buffers are running open loop or closed loop.


----------



## zilch0md

Quote: 





mad max said:


> iBasso should answer your question.  Ask them if the buffers are running open loop or closed loop.


 
   
  I just sent an e-mail to iBasso, asking the question.  Thanks!
   
  Mike


----------



## qusp

thanks for the support guys: and Spud, your right I couldnt help but one last post on the subject. I kept it separate from the reply to kiteki so as to avoid the real possibility of confusion... since hes not actually named/described even a subjective advantage, let alone an objective one. the post roughly translated to 'I like it more, its much more betterer and hes just a big stupidhead'
   
  but first a side note
  Quote: 





kiteki said:


> That is a very accurate assessment of audio science.
> 
> There's quite a few which refuse to look at anything except for numbers.  Luckily I know this sentiment is not shared by all the high-end developers, even within op-amp's / IC's, for the very simple reason we don't have numbers on _everything. (_<-- the faith usually revolves around this.)


 
   
  Interesting, perhaps you should ask Mr Scott Wurcer (the designer of the AD797 who posts regularly on the forum I spend most of my time at, DIYAUDIO) which approach he most values. I happen to believe the 2 are not mutually exclusive, i'm by no means just a number chaser, but I do like my gear to measure well AND sound well. its funny, you seem to be labeling me a number chaser, while from the other side its the opposite.... listening is very important, but personally I feel the design should be competent before listening tests begin.
   
  The grey 1206 caps decoupling your regulators and buffers on your Acko gear, they are 10 or 100nf murata or kemet np0.
   
  hes an obsessive and highly qualified RF and control systems engineer, hardly magic.


----------



## qusp

*eh, whatsyername:*
   
  Here we notice that you took issue with one sentence in my post, the part about tempco and the rest, possibly because it was inconvenient; was completely ignored and replaced with sarcasm and other more ugly ways to distract from my questions. The tactics used to distract include feigning the inability to decipher the entirety of that post, so you didnt have to answer any of the simply framed questions within it, which if not understood indicate some sort of deficit.....
   
  Its not me thats ignoring the datasheet, ignoring current path and ignoring possible resonance, while presenting no objective OR subjective reasoning; it was just a throw away line with nothing behind it and when prompted to explain it, you throw off by insulting me..
   
  Tell me; recommending a larger cap to someone in a design he does not know, in a build that is overheating and very likely already unstable/oscillating at high frequency, to a person without the means to check for said resonance; in your expert opinion is this good advice?
   
  If there were no local caps, I would need to look at the specific application/schematic to know if I disagreed; but np0 or x7r, 1uf or larger is way too large and potentially problematic (even negating the rest) if there are other small decoupling caps nearby. even 10 or 100nf may be borderline too large. more does not = better by default here, it has much more potential for negative effect than positive, as the frequency of interest is going to be high above the LPF presented by 1uf, the smaller cap will cover it easily, likely even 1nf would. Without going to look at some pictures, tell me, do you yourself have some insight into the design you havent mentioned? I didnt think so....
   
  a 100nf 1206 size np0 of reasonable quality will set you back $0.70->1.10AUD, the 1uf X7R is about half that at digikey, with the difference being much smaller at mouser. if buying for production, sure you'de be silly not to consider it, but not without making sure its needed or even desireable. We are not talking about large production here though, so there might be max 3-4 dollars difference here to add them to all the AD797....
   
  We ARE talking about high frequency bypassing.... thats not black magic; whether the timing of it is relevant is moot and is just one of the advantages of the np0, which are generally higher grade overall and often less microphonic, not just better tempco. While being otherwise similar in materials, the construction and terminations are quite different, there is not a single spec in the datasheet where Class 1 is bettered by Class 2 (the same datasheet includes x7r and np0 of that range
   
*classifications used to describe x7r ranges at digikey. *
   
  automotive, general purpose, boardflex sensitive. automotive boardflex sensitive
   
*classifications used to describe np0 at digikey*
   
  automotive, general purpose, high reliability
   
  taken directly from the datasheet for the TDK GRM range  X7r and c0g
  Quote: 





> [size=10pt]Even below the rated voltage, if repetitive high frequency AC or pulse is applied, the reliability of the capacitors may be reduced. [/size]


 
   
  ^ Class 1 is MUCH less effected
   
  Quote: 





> 2-3. Frequency When the capacitors (Class2) are used in AC and/or pulse voltages, the capacitors may vibrate themselves and generate audible sound.


 
   
  SRF is self resonant frequency vv
  Quote: 





> [size=10pt]2) Surface temperature including self heating should be below maximum operating temperature. (Due to dielectric loss, capacitors will heat itself when AC is applied. Especially at high frequencies around its SRF, the heat might be so extreme that it may damage itself or the product mounted on. Please design the circuit so that the maximum temperature of the capacitors including the self heating to be below the maximum allowable operating temperature. Temperature rise at capacitor surface shall be below 20°C) [/size]


 
   
  of course the above will bve too long for ADD man


----------



## kiteki

qusp said:


> [/]
> Interesting, perhaps you should ask Mr Scott Wurcer (the designer of the AD797 who posts regularly on the forum I spend most of my time at, DIYAUDIO) which approach he most values. I happen to believe the 2 are not mutually exclusive, i'm by no means just a number chaser, but I do like my gear to measure well AND sound well. its funny, you seem to be labeling me a number chaser, while from the other side its the opposite.... listening is very important, but personally I feel the design should be competent before listening tests begin.
> 
> The grey 1206 caps decoupling your regulators and buffers on your Acko gear, they are 10 or 100nf murata or kemet np0.
> ...


 
   
  I didn't actually intend to label you as a number chaser, it was a vague comment.
   
  Not familiar with the AD797 designer, thanks for the info.  I know the MUSES use their listening room and concepts like symmetry, just as much as their number chasing software. =)
   
  Indeed there is no exclusivity, when someone advocates "numbers are everything" or "sighted listening is everything" it's like talking to dolphins.


----------



## qusp

no worries man, sorry you caught some of the spray. I havent grabbed any of the muses yet, i've not been a huge fan of the JRC chips in the past and its too much money to blow on a curiosity. if going for that type of 'tuning' i'de be much more likely to just build a discrete circuit, where you have much greater control of the parameters. the only decent spec on the muses really is the open loop gain, the rest is significantly bettered by the NAT-SEMI (now Ti) and Ti high performance audio and instrumentation range.
   
   
  Quote: 





> Indeed there is no exclusivity, when someone advocates "numbers are everything" or "sighted listening is everything" it's like talking to dolphins.


 
  haha well said.
   
  yeah Scott posts over there quite a lot and under his real name too, so if you search his posts over there, theres some great info


----------



## AmarokCZ

*qusp*: first of all thanks for making you last post more readable!  Second thing: if you think, that I don't know anything you just posted than you're wrong.
  But do you really think that those possible oscillations (because nobody knows what's really happening there) are caused by "something in supply"??? Real problem is that people switch OA blindly without even thinking if it's possible just to switch it.
  Don't you think it's better to remove reason and not just its consequence?
  With good PSU and correctly compensated OA there is no need for good HF/RF/whatewer bypass so few uF of X7R ceramic (or film) is the best, because correctly designed e.g. amp or buffer don't oscillate even without bypass. If X7R caps are overheating in your audio-circuits you should be ashemed of yourself!


----------



## qusp

Spoiler: for%20continued%20argument%20click%20me%2C%20click%20me



 
  coulda fooled me, you suggested that X7R was superior, gave no reason and it read as if you were citing audible differences. you had no idea of the conditions and yet suggested a larger cap that is much more likely to cause trouble, so if you know all that and still made a questionable suggestion, then....
   
  heres the part where I remind you of my first reply, it wasnt my suggestion to apply the caps as a fix, that was Mad Max; I only questioned YOUR suggestion of using a lower grade cap as being superior, or rather posted a 'please explain' which was ignored and substituted with insults. I mentioned a small np0 before my query of you, but that was just as an alternative and in reply to mad max's suggestion
   
  I only suggested that for HF oscillations/ringing a smaller cap of the type that is more effective at high frequencies and heat would be preferable (if he must persist that is, I also made heatsinking suggestions to that end). I explained the tempco ratings; I didnt suggest the single trait of tempco as being the reason, its just that np0 tend to be more linear overall and the naming/grading uses the tempco to identify/group them. This prompted you to single out tempco to argue with.
   
  if you would actually read my first reply (and many more in this thread) I suggested to get the AD797 the hell out of there as they are not really unity gain stable. Even under ideal conditions with all the trimmings they are picky, its a great chip, I love it, but its a baby (a cranky one) and there are much better choices for this job.
   
  If you review my posts in this thread over the last few years, you will note that I have been quite vocal about anti blind rolling high bandwidth and/or picky chips based on reputation in other builds; and with AD797 in particular.
   
  I wouldnt even bother with compensation, sure its a possible fix depending on the issue, but its simply a dead end IMO, wrapping several twitchy opamps inside the loop which is intended for a buffer, which i'd say it is (inside the loop) is asking for trouble and with this chip doubly so.
   
  so your above post is quite humorous to me...


----------



## AmarokCZ

Don't know what is your intention here, but I never wrote that X7R is superior (that's what your mind made up just to start this argument), also you never wrote 'please explain'. 
	

	
	
		
		

		
			





 So if you wanna continue this jibberjabber please PM me since it has nothing to do with OA anymore.


----------



## qusp

but lets get back on topic, i've edited the above to be in a bubble. sorry guys
   
  wow, you really actually have a comprehension problem dont you? sorry, I usually expect a little bit more capability of people in here; I would have thought bolding 2 words and 2 words only in a whole post, in a clearly stated question complete with question mark, could be interpreted as a please explain... I shall remember to be more literal in future. it was the second time I asked it.
   
  just for you, since you seem to have a foggy memory of the occasion
   
   
  Quote: 





> Any particular reason for C0G? For bypassing X7R is even better, IMHO.


 
   
  which is misled and also rather vague


----------



## AmarokCZ

I culd say the same thing, because I asked MadMax why NP0 and that I think that X7R is better for bypassing.
  Your answer was that NP0 is better ... nothing more, where is that 'please explain' you mentioned at post#3922 ... I tell you where: nowhere! Obviously you are "tuned on different wavelength" than me.


----------



## qusp

oh this one, the very next words I uttered
   
   
  Quote: 





> hmm x7r better?


 
   
  and then
   
  Quote: 





> nothing fairy tale about it, it may disagree with your opinion, but we are talking about a hot case here and we are talking about bypassing high frequency energy, a small higher quality ceramic will do just fine. just what LPF do you think you will get with a few uf and why is it that you think there will be anything to bypass at such a low frequency? for decoupling sure, for bypassing 100nf or 10nf is just fine and for low values where np0/c0g is available, there is simply nothing superior about x7r, its only advantages are *cost* and *higher capacity*, there are no other advantages. if you go too large for a bypass it would be fairly easy to cause resonance with the local decoupling/supply caps, smaller values are much safer in this regard
> 
> fine you have some sort of preference here, thats cool, but please do not try to pass it off as fact, *I would like you to supply one advantage above the 2 I have supplied above please?* across the rails vs each rail to ground is a preference thing as I see it. if you need to add more than a small amount the design is flawed


 
   
  i've hilighted it for you just in case
   
  it seems your brain switches off under difficult situations, its like you became rabid when I dared to explain the tempco ratings system, sorry if you thought this condescending because _you knew it all already_, but when someone claims an inferior, lower grade part is actually better, it prompted me to make sure you knew what you were saying. OPn here that usually means someone is claiming audible/subjective preference for the lower grade part, which is also valid, but you did not put forward any reasoning at all
   
   
  I still havent got a reply to either btw


----------



## AmarokCZ

I see that you will not accept you blunder, that OK with me.
  In your free time I reccomend you to visit one of our local forums, you will certainly be surprised by knowledge of our members and be sure that if they would see someone like you babbling those nonsences you posted above they would literally stone you to death.


----------



## SpudHarris

Well why don't you jog on to ''one of our local forums''  and leave this thread.....


----------



## WiR3D

Quote: 





amarokcz said:


> I see that you will not accept you blunder, that OK with me.
> In your free time I reccomend you to visit one of our local forums, you will certainly be surprised by knowledge of our members and be sure that if they would see someone like you babbling those nonsences you posted above they would literally stone you to death.


 
  Yeah seriously just go, you have trolling. and its starting to annoy everyone, you blatantly denying what you said earlier, I have been reading all of the posts.


----------



## AmarokCZ

Please quote what I wrote and then denied or stop provoking!


----------



## Currawong

Guys, take it to PMs.


----------



## zilch0md

Mad Max,
   
  Quote: 





zilch0md said:


> I just sent an e-mail to iBasso, asking the question.  Thanks!
> 
> Mike


 
   
  I asked iBasso:           "In the PB2, are the buffers running open loop or closed loop?"
   
  Here's their response:  "It is closed loop."
   
   
  Quoting qusp: 





> do you know if the buffers are running open loop or closed loop in your amp? ie are they wrapped in the feedback loop of the voltage gain stage (the 1612) or do they follow that stage, with only their own local feedback loop? basically you will wire the bulb (small suitably rated incandescent) from left channel or right channel to ground, or if its balanced from the positive to negative phase of one channel. you can leave it as silent with no music but with the volume turned up and if you are getting flickering light you have oscillation.


 
   
  Thanks!
   
  Mike


----------



## qusp

no worries, yeah I figured it would be, the AD797 has a unity gain bandwidth of approximately 30Mhz (forgetting the effects of load impedance and temp, which lower it further), the opa1612 has a closed loop gain of 40Mhz, even without all of the other stuff, lack of compensation, stability, resonant power supply, lead inductance etc etc, this cannot work without lowering the bandwidth of the opa1612. its never a good idea to have a slower opamp wrapped in the loop of a faster opamp. sorry mate, I just do not see how you can make this work, there is no doubt your amp is oscillating and to top it off, the edge on the slew of the ad797 becomes more violent with higher temp and opa1612 needs special setup to handle these conditions, this setup is missing.


----------



## jude

Be civil, guys.


----------



## Mad Max

Quote: 





qusp said:


> no worries, yeah I figured it would be, the AD797 has a unity gain bandwidth of approximately 30Mhz (forgetting the effects of load impedance and temp, which lower it further), the opa1612 has a closed loop gain of 40Mhz, even without all of the other stuff, lack of compensation, stability, resonant power supply, lead inductance etc etc, this cannot work without lowering the bandwidth of the opa1612. its never a good idea to have a slower opamp wrapped in the loop of a faster opamp. sorry mate, I just do not see how you can make this work, there is no doubt your amp is oscillating and to top it off, the edge on the slew of the ad797 becomes more violent with higher temp and opa1612 needs special setup to handle these conditions, this setup is missing.


 
   
  I suggested that he use AD8597 in place of the troublesome AD797.  He should replace OPA1612 with ADA4610-2 then?  It's closed loop bandwidth is 10.6MHz, very close to AD8597's 10MHz.
  So the two chips should be equal in bandwidth for the setup to be stable then?  This is good to know.


----------



## Avro_Arrow

The buffer needs to be somewhat faster than the voltage gain stage.
  If they are too close together you could get problems caused by the
  phase shift of the buffer at it's upper frequency limit.
   
   
  Quote: 





mad max said:


> I suggested that he use AD8597 in place of the troublesome AD797.  He should replace OPA1612 with ADA4610-2 then?  It's closed loop bandwidth is 10.6MHz, very close to AD8597's 10MHz.
> So the two chips should be equal in bandwidth for the setup to be stable then?  This is good to know.


----------



## qusp

yep, the buffer should be faster, sorry perhaps I should have been more specific. AA has explained it well, thats why chips like buf634 and the lme49600 are so wide bandwidth and most likely why they have given us a wide bandwidth mode, the bandwidth isnt needed for audio thats for sure (cheeky, I know thats gonna get a comment) so that for example teaming with the 1612, its only 40Mhz, the lme's normal, low Iq mode is 100/110mhz so it will handle all but the most nutso high speed chips.
   
  to find the AD797s bandwidth at unity I used the open loop gain + phase vs frequency plot, as they only quote bandwidth at much higher gains. besides that, that whole front page section of the ad797 datasheet is a bit whack, I wouldnt trust all the numbers on the front page. for the GBW numbers they give
   
  [size=9.000000pt]110 MHz gain bandwidth (G = 1000)
 8 MHz bandwidth (G = 10)[/size]
   
  which doesnt make any sense, negative feedback as a process uses up gain to extend bandwidth and vice versa, feedback used to increase voltage gain will LOWER bandwidth, so the bandwidth for G=10 above should be higher, not lower than the bandwidth for G=1000. i'm not the first to mention this error either. the front page of these things is usually written by the marketing department, not the technical writers.
   
  also Mad Max, just in case you took this as a glancing blow, I meant nothing by singling you out as the person that suggested the additional caps; I know it was *just one* of the suggestions you made, in case he stubbornly pushed ahead with AD797 as he apparently likes the sound of oscillation 
	

	
	
		
		

		
			





 hehe shimmering highs zilchomd?
   
  I only meant to point out it wasnt me


----------



## kiteki

Which temperature between 20 and 45 C should I use to desolder an op-amp like this?
   
  Thanks in advance.


----------



## qusp

Quote: 





kiteki said:


> Which temperature between 20 and 45 C should I use to desolder an op-amp like this?
> 
> Thanks in advance.


 
  huh? 20-45C? thats just above body temp =)
   
  what sort of tool will you be using?


----------



## Mad Max

Quote: 





qusp said:


> yep, the buffer should be faster, sorry perhaps I should have been more specific. AA has explained it well, thats why chips like buf634 and the lme49600 are so wide bandwidth and most likely why they have given us a wide bandwidth mode, the bandwidth isnt needed for audio thats for sure (cheeky, I know thats gonna get a comment) so that for example teaming with the 1612, its only 40Mhz, the lme's normal, low Iq mode is 100/110mhz so it will handle all but the most nutso high speed chips.
> 
> to find the AD797s bandwidth at unity I used the open loop gain + phase vs frequency plot, as they only quote bandwidth at much higher gains. besides that, that whole front page section of the ad797 datasheet is a bit whack, I wouldnt trust all the numbers on the front page. for the GBW numbers they give
> 
> ...


 
   
  BUF634 and LME49600 will kill the battery life like no other.  ISL28218 in place of 1612 then?  lol
  So somewhat faster, he says?  Like OPA1652 + OPA827?
  Or just stock opamps and no more fussin'!
   
  What's 1612/1611's "Full power bandwidth"?  How do you get that?  It is a mere 4MHz.


----------



## kiteki

Oh... I meant 200 - 450 C lol!
   
  I'm using a soldering iron, any other tool you recommend? =)
   
  p.s. Where do I learn how to design a PCB?


----------



## zilch0md

Mad Max / qusp / Avro_Arrow:
   
  You guys are really putting the brakes to my haphazard rolling of op-amps!   And that's a good thing, for sure.
   
  For the record, I've pulled the AD797s out of the buffer stage of my PB2 and replaced them with dummy buffers - because the heat alone is an obvious indication that something was dreadfully wrong.  But I did like the sound of the AD797s as buffers with OPA1612s in the voltage gain stage (as A_A would say it), and I must insist that I didn't hear anything undesirable in the highs.  I must have poor taste - preferring moonshine (oscillation) to an expensive single malt whiskey (no oscillation).
	

	
	
		
		

		
		
	


	



   
  Having read the posts on this page, above, I'm ready to just do what I'm told. I don't know what I'm doing.  Enough of rolling blindly.  I'd rather be smart about it, even if that requires putting my trust in your hands.  I firmly believe that you know what you're doing.  Sorry to burden you with that, but hey - you guys are dialed in!  
	

	
	
		
		

		
		
	


	



   
  I have to say that I was enjoying my music a whole lot more when I was using a Stepdance - where I wasn't obsessed with tweaking the sound.   The PB2 has been a lot of fun, but my lack of knowledge has made the whole thing a joke - and I'm convinced from reading your posts that MOST people who roll op-amps are as clueless as I am.
   
  So if you can recommend something for the PB2's closed loop buffer stage that's "compatible" with the OPA1612s, I will just go with that and back off on further rolling.
   
  Currently, I'm in possession of these buffers, but would gladly purchase anything you recommend, as I find that all of these reduce detail across the spectrum compared to running the OPA1612s with dummy buffers, with the HA5002s being the least offensive in this regard:
   
  HA5002  x4
  BUF634P x4 
  BUF634U x4
   
  Here's my entire collection:
   
   This is the stock set that comes with the iBasso PB2.
   

   
  But please don't limit your suggestions to what I've currently got in my tiny inventory.  
	

	
	
		
		

		
		
	


	



   
  Remember - I'd really like to stick with OPA1612s, for starters.
   
  Edit:  And by the way, I have no concern for battery consumption - I use an Energizer XP8000 external battery pack, exclusively, to get a constant, regulated 16V supply.  The inline voltage regulator cable (XPAL WI16) sees 21 VDC when the 5-cell Lithium-ion pack is fully charged, but the PB2 sees a constant 16V, even as the battery pack discharges to 16V (when it's game over).  I've easily used the PB2s internal battery pack for less than 30 minutes total, across six weeks of having the PB2.   If anyone thinks I should use a lower voltage, I also have a 15V regulator cable for the XP8000.
   
  Thanks!
   
  Mike
  (Willing to follow your lead...)


----------



## Avro_Arrow

Have you tried stacking your BUF634U?
  You can quite literally stack them one on top
  of the other...
  The "best bang for the buck" stack is four, but
  it is not uncommon to see as many as eight.
  In your situation, though, two is probably the
  limit your board will support.
  In proper use, each buffer would have it's own spot
  on the board...but in a pinch they can just be stacked
  one on top of the other.
  LME49600 can also be stacked.
   
  LME49990 and LME49600 (BUF634) is a pretty
  good combination.
   
  I can not say how they will perform in your situation, though.
  Layout will determine the maximum performance as much
  as proper component selection.


----------



## SpudHarris

Mike, I told you that you can get OCD about rolling. But you are right to draw a line in the sand and take some advice from the 'Gurus'. I've been doing this for a long time and I'm probably no further along than yourself but I have learned a few things along the way.
   
  Even if you get a combo that you like and it's not causing hassle, you will be searching for the holy grail again within a week. I went through the same thing as you, I got so bogged down by trying to find the perfect sound for me that I lost track of why I was listening at all. Take my advice and find something that you like (OPA1612 by the sounds of it is your flavour) stick in the HA5002 buffers close up the PB-2 for a minimum of a week and just start enjoying your tunes again. The problem with obsessive rolling is that not only do you not get to enjoy your music, you rarely get to know what difference the OpAmps make before you are dropping them again for the new best thing.
   
  Get back to your tunes and chill


----------



## leeperry

the really funny thing is that OCD'ed opamp rollers can rave about an opamp, even though it's oscillating like hell in their gear(AD797 anyone?) and yet properly implemented cheapish opamps such as OPA627AP and OPA2132P can sound out of this world when put together by a skilled EE who also happens to have ears(which is very rare apparently).
   
  I don't think you could ever get anything good out of 5532's or 49720's, but the chips I just mentioned can sound mind blowing when properly implemented within a dual mono design(don't push your luck by using dual opamps on stereo signals, though ^^)
   
  rolling opamps w/o an oscilloscope is like trying to calibrate a display to D65/2.3 w/o a colorimeter, good luck w/ that


----------



## zilch0md

Hi,
   
  Quote: 





avro_arrow said:


> Have you tried stacking your BUF634U?
> You can quite literally stack them one on top
> of the other...
> The "best bang for the buck" stack is four, but
> ...


 
   
  Thanks for the recommendation.  Ignorance speaking here, but I thought that even though stacking yields more current, it comes with the expense of even less transparency - as a rule.  Is that true?   (School me!)
   
  Thanks!
   
  Mike


----------



## zilch0md

Quote: 





spudharris said:


> Mike, I told you that you can get OCD about rolling. But you are right to draw a line in the sand and take some advice from the 'Gurus'. I've been doing this for a long time and I'm probably no further along than yourself but I have learned a few things along the way.
> 
> Even if you get a combo that you like and it's not causing hassle, you will be searching for the holy grail again within a week. I went through the same thing as you, I got so bogged down by trying to find the perfect sound for me that I lost track of why I was listening at all. Take my advice and find something that you like (OPA1612 by the sounds of it is your flavour) stick in the HA5002 buffers close up the PB-2 for a minimum of a week and just start enjoying your tunes again. The problem with obsessive rolling is that not only do you not get to enjoy your music, you rarely get to know what difference the OpAmps make before you are dropping them again for the new best thing.
> 
> Get back to your tunes and chill


 
   
  I believe every word of this, Spud!  I kid you not, I've had sessions as long as six hours straight, rolling, rolling, and rolling some more.  Three to four hours straight is commonplace.  I've gone koo-koo!
   
  And yes, I've only once gone an entire week without rolling.  
	

	
	
		
		

		
		
	


	



   
  But yeah, I'm in the "chill phase" for now, just enjoying the OPA1612s with dummy buffers, but I'm not sure that's "safe".  
   
  Sheesh - I should have bought an SR71B to go balanced - no brains required.  
	

	
	
		
		

		
		
	


	




   If it weren't for the fact that I actually hear differences, I wouldn't be so tormented.  (First world problems!  I'm so spoiled!)
   
  Mike


----------



## zilch0md

Quote: 





leeperry said:


> the really funny thing is that OCD'ed opamp rollers can rave about an opamp, even though it's oscillating like hell in their gear(AD797 anyone?) and yet properly implemented cheapish opamps such as OPA627AP and OPA2132P can sound out of this world when put together by a skilled EE who also happens to have ears(which is very rare apparently).
> 
> I don't think you could ever get anything good out of 5532's or 49720's, but the chips I just mentioned can sound mind blowing when properly implemented within a dual mono design(don't push your luck by using dual opamps on stereo signals, though ^^)
> 
> rolling opamps w/o an oscilloscope is like trying to calibrate a display to D65/2.3 w/o a colorimeter, good luck w/ that


 
   
  I hear you leeperry!   I needed a spanking!


----------



## qusp

Quote: 





avro_arrow said:


> Have you tried stacking your BUF634U?
> You can quite literally stack them one on top
> of the other...
> The "best bang for the buck" stack is four, but
> ...


 
   
  oh lordy yes it is 
	

	
	
		
		

		
		
	


	




 am I doing it right?
   
  got buffers? 
	

	
	
		
		

		
		
	


	



   

   
   

   
  ^^ pictured with a pair of Scanspeak 18W/8531 G0 6.5" mid/woofers, which will take me down to about 30Hz in a ported enclosure till I add some larger 10" Volt pro woofers.
   
   
  and an lme49990 based balanced input 'instrumentation amp' underneath

   
  The above is opc's 'the wire' LPUHP (Low Power Ultra High Performance) parallel buffers taken all the way baby, to make a 15W/ch dual mono low wattage power amp with the craziest numbers and audio youve ever seen. i'm using it for my tweeters in a ESS dac based quad mono balanced digital crossover for some speakers i'm building (like a hardcore JH3A for speakers).
   
  This is correct use of X7R caps, see there are no other nearby caps of similar size to cause resonance and I needed a larger value than available in np0 because of that; its also a high end build so a few bucks isnt worth saving, but X7R is best suited for the job. These are 1206 size 10uf with the only caps beforehand being in the main PSU and they are 4700uf.
   
  the ones on the lme49990 are also X7R, but only 1uf due to much lower current demand, but even though the power delivery is via solid planes and vias, the main supply caps are a fair way away and a physically small 1uf cap was needed, no suitable np0 was available and probably not even desireable.
   
  the buffers use plenty of current in this format, so larger caps from each supply pin to ground are most definitely needed, its a 3 layer PCB so the middle is basically all ground plane and the other 2 are for signal and power routing.
   
  The design has been publicly poked, prodded and probed to within an inch of its life with no signs of instability. Its designed to drive 15W into an 8ohm speaker load so it needs larger than a .1uf, these are acting as decoupling caps and small reservoirs for transients.
   
  I'm also going to bring it along to the next headfi meet with a novelty HE5/6 cable, I think its going to suit them down to the ground. except extreme loading conditions the copper in the PCB is enough to take the heat, but in summer it'll need its heatsink, which will be custom CNC for a couple of our group for bater.
   
  For those that care, wires are 20awg VHAUDIO UPOCC copper in foamed PTFE and the insane overkill output wiring is VHAUDIO 10AWG twisted pair UPOCC in FEP (this is actually AC wiring, but its so nice I thought it was perfect)
   
   
  and heres its little brother in balanced mode on the output of one of my dacs, breadboard testing, not final layout, as you can see i'm testing a thermonuclear device for transparency =) . Thats a pair of balanced HD600 (with lemo 4 pin connector), directly on the output out of frame. The bal-bal wire is acting as the output stage/IV for the dac and headphone amp, sounds magic! so yeah opamp rolling is fun, but it soon leads you to this madness haha
   

   
  are we having fun yet?


----------



## qusp

Quote: 





zilch0md said:


> I hear you leeperry!   I needed a spanking!


 
   
  dont worry about him, he was one of the craziest roll by ear users on this forum for a long time, that would not listen to anyone. I qualified for that title too for quite a while, well perhaps a bit less doggedly. the pros often dis opamp rollers, but I disagree, its often where you get the taste for electronics on more than a surface level and if you have the hunger for learning, I guess thats when the training wheels come off. I wonder if LP actually has a scope himself, he certainly wouldnt have even entertained the thought a couple of years ago
   
  please dont label me Guru, i'm far from a guru, i'm still learning every day and the ins and outs of this particular area wrt phase i'm just poking around on the surface. I need to get more time on sims, unfortunately spice doesnt come on mac and I havent gotten around to installing windows on here yet, solely for sims etc
   
  @ Spud, dont worry, I saw the inverted commas on guru


----------



## WiR3D

Quote: 





qusp said:


> *snip awesum stuff*
> 
> are we having fun yet?


 
  can I buy a set? looks seriously awesum.


----------



## leeperry

Quote: 





zilch0md said:


> I hear you leeperry!   I needed a spanking!


 
   
  You apparently do 
   
  But no worries, blind rolling is hell fun! too bad the best chips will never be stable w/o a EE background in order to know how to get them stable.....I've given up on opamp rolling altogether and I also avoid gear using 45xx/553x/497xx's. So far, so good 
	

	
	
		
		

		
		
	


	



   
  Having access to an oscilloscope is mandatory, but afterwards you'll need to know how to overcome those nasty oscillation issues....otherwise you'll have no clue what to do. If you're lucky, adding decoupling caps will help.....but the most pesky and arguably best sounding chips will be far more finicky to deal with. It's actually a job in its own right, all it takes is a mere EE diploma if you fancy playing God in a more serious manner than the "look, ma! no hands" blind rolling hit & miss experience


----------



## genclaymore

I been thinking about trying some op-amps that has a sound signature similar to tube but I don't know any that has that sound signature. Mainly Dip-8 so i don't have to try to get some one to solder it. i do have a adapter in case it's single channel.
  
  Mainly a tleast tube sound signature while not being too bright and have a tight bass it having a big sound stage is a plus but not a most.


----------



## kiteki

The OPA627 is often called coloured, analog etc., perhaps use 072D as a buffer, random thought.


----------



## kiteki

> "look, ma! no hands" blind rolling hit & miss experience


 
   
  What's so hard about it though, there should be a tutorial on op-amp environments, it feels like there's an ivory tower surrounding basic electronic circuits and capacitors.
   
  Like, I'd love to improve the 50 cent or less op-amps in devices like the Teclast T51 or Colorfly CK4 to $5 op-amps however the reaction is usually _"I suspect you need to understand x/y/z in the circuit or there will be solar flares" _ is not really helpful.
   
  Edit:  At the same time half this forum thinks all op-amps will sound identical in their ideal circuit, and op-amp rolling is really only messing with voltage / colour / distortion, which isn't helpful either.  It's like saying "don't mess with your TV image / laptop / air-conditioner an EE has already calibrated it to perfection in it's ideal circuit" ...


----------



## kiteki

The MUSES and some other rare op-amps arrived today, will experiment with them when I'm in the zone.


----------



## WiR3D

Quote: 





kiteki said:


> What's so hard about it though, there should be a tutorial on op-amp environments, it feels like there's an ivory tower surrounding basic electronic circuits and capacitors.
> 
> Like, I'd love to improve the 50 cent or less op-amps in devices like the Teclast T51 or Colorfly CK4 to $5 op-amps however the reaction is usually _"I suspect you need to understand x/y/z in the circuit or there will be solar flares" _ is not really helpful.
> 
> Edit:  At the same time half this forum thinks all op-amps will sound identical in their ideal circuit, and op-amp rolling is really only messing with voltage / colour / distortion, which isn't helpful either.  It's like saying "don't mess with your TV image / laptop / air-conditioner an EE has already calibrated it to perfection in it's ideal circuit" ...


 
  I agree completely its very daunting for a beginner. There is simply no tutorial. And there should be one, a big one, explaining the equation, bipolar vs fet and the dangers and some notable exclusions (AD8599). Also oscillation, and bypassing. Then slew rate and bandwidth. There is s much that I barely get.
   
  maybe an article should be made where more then one person can contribute? just lay out the headers and take it from there.


----------



## Avro_Arrow

There is already one of the best sources of information online...the manufacturers Data Sheet.
  Tanget has some good articles on op amps here.
  Look in the section titled "Op-Amps in Detail".
   
  Designers have some goal in mind when they create a layout which may include
  some sever compromises such as limited size or designers experience...
  These compromises can limit the maximum usable bandwidth that you can
  get out of the board no matter what components you stuff into it.
   
  Quote: 





wir3d said:


> I agree completely its very daunting for a beginner. There is simply no tutorial. And there should be one, a big one, explaining the equation, bipolar vs fet and the dangers and some notable exclusions (AD8599). Also oscillation, and bypassing. Then slew rate and bandwidth. There is s much that I barely get.
> 
> maybe an article should be made where more then one person can contribute? just lay out the headers and take it from there.


----------



## qusp

Quote: 





> What's so hard about it though,


 
   
   
  nothing that hard about it, past knowing how to verify what you have done has actually improved matters, I agree LP did present it a little too extremely, but thats what he does for effect =) however there is most certainly truth in what hes saying. there is no general guidelines of which chip will go well where, replacing X for Y, Each chip has its own set of preferred operating conditions and each circuit represents a set of parameters of its own, even when the parts are the same, the lead, or trace inductance, grounding, gain, compensation, power supply voltage and load current, capacitance, as well as parasitic and/or parallel capacitance, inductance etc; all have influence on these parameters.
   
  bipolar or fet is a minor thing, that will tell you little and cannot be used to make decisions. the datasheet and knowing how to read a layout, as well as having some way to verify performance is the only way to do it. simulation can help to a degree too, but even when spending a great deal of time creating complex models there are still some elements that will be unknown until its done in reality and thats if you can get an accurate model, or be able to trust the datasheet enough to build one based on that. the best models come from building and measuring the real thing, then you have the change from loading....
   
  a basic scope can be had for pretty cheap and unless you are really needing to play with high bandwidth parts, should be enough to get a rough idea. handheld ones are starting to become more useful, but you still cannot beat an old analogue scope for value.
   
  of course as mentioned, I didnt even touch dealing with the incompetence of the designer, or otherwise compromised designs
   
  that being said, there are ways to make sure what you are doing is safe, or likely to cause damage, many of which have been discussed in the last few pages; you can still have fun, but know when to recognize the signs something is really wrong. you WILL hear differences, because of the change in conditions, some may even be preferred, whether you have made an improvement or not is all relative, if you like the sound better and the amp isnt going to kill itself or your headphones, then hey I call that a win.
   
  do remember though and this is important, we are talking about audio bandwidth here, the blinkered chase for high slew rate and wide bandwidth at all costs is not all that relevant for our purposes; in the same way that oven controlled oscillators are not relevant either, only the OCX do tend to be a higher grade part overall, nothing to do with being ovenised
   
  @WiR3D: which build were you talking about? the LPUHP amps? the GB is over, there was a single run of blank PCBs, no kits were available, the PCBs sold out in less than 24hrs!! I ran the group buy for the passives, custom transformers from sumR and keratherm thermal interface material to drive the cost down, people sorted the actives out themselves. there will not be another run of PCBs


----------



## zilch0md

Excellent comments, everyone, but a datasheet in the hands of a beginner is what led me to trying the AD797s in the buffer stage of my PB2, with OPA1612s in the L/R - a combination which sounds great to my ears - I truly can't hear anything undesirable - quite to the contrary, it sounds wonderful, but for everything getting so hot I have to remove the top of the case to use it - and now that I've been warned that the op-amps themselves might still get so hot as to destroy my LCD-2s, I'm deprived of this wonderful sound - and completely incapable of discerning whether or not there really is an actual risk of damage, because I have neither the knowledge nor the test equipment of an experienced EE and throwing money at the test equipment is easy enough, but even then I wouldn't know how to use it.
   
  Back to the AD797 datasheet having pointed the way to this fiasco, it was these words that gave me the light-bulb idea to drop them into the buffer stage:
   


> The low distortion and 16-bit settling time of the AD797 make it ideal for buffering the inputs to Σ-Δ ADCs or the outputs of high resolution DACs.


 
   
  I knew perfectly well that my PB2 is not a sigma-delta ADC or DAC, but the word "buffer" was all I needed to see to imagine their use in the buffer stage of my PB2.  The sound is so wonderful to my ears, colored, yes, not neutral, but warm, with lots of control in the bass, very little loss of detail across the spectrum as compared to running the OPA1612s with dummy buffers, but I'm having to exercise self-discipline to avoid using this ear-candy combination!   Like a former cigar smoker who just found a rare Cuban in the bottom of his humidor, I can't have it because it might give me cancer.
   
  Conclusion (I'm not as bitter as this may sound, but it's the truth, just the same):   Rolling op-amps is a complete joke for all but a relative handful of people who truly do have the knowledge and the test equipment.  Everyone else should just stick to buying off-the-shelf designs. If you want a different sounding amp, buy a different sounding amp.  
   
  Still, it has been a lot of fun.  And, undermining my own arguments, above, it will no doubt continue to be a lot of fun, cause I'm gonna smoke them Cuban cigars!
   
  Mike


----------



## leeperry

You don't become an EE overnight basically. You may wanna have a look at this document, especially regarding AD797: http://e2e.ti.com/support/amplifiers/precision_amplifiers/w/design_notes/upgrading-op-amps-in-audio-equipment.aspx
   
  That's AD797 in the ONE: http://www.head-fi.org/t/542563/asus-essence-one-headphone-amp-dac-cebit-2011/810#post_8300531
   
  Gluing a giant heatsink on top of your DAC is *not* a practical solution ^^
   
  Anyway, I believe we've beaten this subject to death.....blind careless rollers can keep rolling mindlessly if they like, nothing wrong w/ that


----------



## qusp

You cant blame the datasheet for that, there is a huge difference between using 1 opamp per phase in a PCB designed for it with a proper ground plane, well compensated and driving the rather benign high impedance load of an amplifier input (the dac before it has nothing to do with it) and stacking 4 per channel in a PCB not designed for it, without supporting components and driving a headphone load which is many orders of magnitude harder than the high impedance of the amp. worlds apart.
   
  the first rule you need to learn is ohms law, its at the heart of almost any design. its a common mistake around here and there is a certain amount of misinformation surrounding it, that a high impedance load is harder to drive than a low impedance load. In fact the opposite is true, provided you have the voltage swing in the power supply plus losses, a very high impedance draws very little current and hardly loads the amplifier at all.
   
  A low impedance load requires a LOT more current and is far harder to drive in a linear fashion, to the point many amps will actually go into current limiting, roll off the high current bass lines and distort. it creates much more heat and stresses the chip. the lower the load impedance, the closer to a short circuit it becomes.
   
  think of it like connecting a resistor across the output of your amp, think of this as the headphone load, (impedance and resistance are similar) in fact for load testing this is exactly what many designers will do if they dont own an electronic load. so the less resistance in that resistor, the more the amp wants to push current across, lower and lower and lower until you have zero impedance/resistance, in other words a short circuit, almost pure current; we all know a short circuit isnt an easy load on an amplifier is it? not good
   
  probably the first thing that would give if you kept using it like you were, is the caps surrounding it, you can bet they didnt use 105c caps, more like 85c max, because they presume someone will cease operation if the amp is too hot to hold..... audiophile approved caps are rarely 105c, so they will eventually dry up and fail, if you are lucky they will fail closed and short the amp, maybe trigger a protection circuit, if they fail open you could see the full power supply rail DC at the headphones
   
  but I did not say anything of the sort, roll to your hearts content, but keep your eyes open and if something doesnt seem right, chances are it ISNT right
   
  would you drive a Ferrari around Le mans in 1st gear, revving the crap out of it just because it was making a fantastic noise?


----------



## leeperry

That reminds me of me raving about the AD797B as I/V and LT1028AC as buffer on the HD2.......killer SQ considering that it's using the AK4396 "miracle DAC" w/ two discrete clocks for 44.1/48kHz multiples 
	

	
	
		
		

		
		
	


	



   
  Then one day out of the blue, AD797 completely refused to work anymore, and then LT1028 shortly afterwards...AD797 would make a very loud whining noise and whatever 1028C or AC would give some very high pitched sound for a second and then become dead silent =/
   
  The board worked fine w/ UGS opamps, mind you!
   
  I poisoned quite a lot of ppl to try this set up and one of them came up w/ a dirty fix involving resistors in order to lower the gain of the buffer to -1 hence making LT1028 happy. It was a success apparently! But all boards died a few months later duh ^^


----------



## zilch0md

qusp and leepery,
   
  Thanks again for your comments.
   
  For the record, I wasn't blaming the data sheet for my decision to try the AD797s in the buffer stage - I was blaming my inability to interpret the datasheets - and the inability of the vast majority of people who roll op-amps.  
   
  In other words, a datasheet is of little value to a guy like me.  I know it must be hard for the more knowledgeable people to dumb down to my level, but seriously, easily half of what you write, goes right over my head, and yes, I know that it takes a lot of time and reading to come up to speed on this stuff.  I'm trying. I want to learn.  
	

	
	
		
		

		
		
	


	



   
  Even when I wrote that I was going to smoke my Cuban cigars, I just meant that I will probably continue to roll op-amps WITHOUT the knowledge and test equipment I lack - because it's fun and I CAN hear differences.  I didn't mean that I would continue to use the AD797s as buffers with the case getting so hot.  Believe me, I respect your warnings and do not want to fry my LCD-2s.
   
*Meanwhile, I decided to send an e-mail to iBasso, asking them about use of AD797s in the buffer stage and the overheating problem.  (Note that iBasso ships the PB2 with AD797s included their rolling kit.)*
   
  Here's my e-mail to iBasso:
   
  Quote: 





> Date: Tue, 12 Jun 2012 00:17:50 +0000 (GMT)
> To: iBasso Audio <service@ibasso.com>
> Subject: Questions about use of AD797 in buffer stage of PB2
> 
> ...


 
   
  And here is their response:
   
   
  Quote: 





> Date: Tue, 12 Jun 2012 21:44:12 +0800
> From: iBasso Audio <service@ibasso.com>
> Subject: Re: Questions about use of AD797 in buffer stage of PB2
> 
> ...


 
   
   
   
  So, according to iBasso, it's normal for the AD797 to run hot, but they want to know how hot, even with the lid off.  They don't believe I need to use bypass capacitors on the AD797s in either the voltage gain stage or the buffer stage - iBasso believes the AD797 will be stable at either location - but it sounds is if they're saying the AD797 isn't an ideal buffer because its output current is only 50 mA.  (Which doesn't bother me, as I'm using LCD-2, not something current hungry like the HE-6.)
   
  Now, I guess I have to buy one of those those laser thermometers, if I want to continue this exchange with iBasso.  Is there a better way (a right way) to measure the temperature of the AD797s?  
   
  Can anyone think of any other questions I should ask iBasso?
   
  Does anyone think this guy at iBasso might be steering me wrong?
   
  Thanks!
   
  Mike


----------



## WiR3D

Quote: 





leeperry said:


> That reminds me of me raving about the AD797B as I/V and LT1028AC as buffer on the HD2.......killer SQ considering that it's using the AK4396 "miracle DAC" w/ two discrete clocks for 44.1/48kHz multiples
> 
> 
> 
> ...


 
  oh god, Lol I have a long list of opamps I was about to buy for my STX that you used to roll a few years ago, especially the LT ones. good thing I trimmed it down lol. I'll still come ask for confirmation here before I buy anyway. I love the AD797 in my STX with my AKG K242HD, it really does sound good, but the treble makes you bleed, probably from oscillation. So I took it out. Now running THS4032, its the most neutral, suits my Denons and the AKG's without the harsh treble and an overall smooth signature. But they are also very high bandwidth, and correct me if I'm wrong but that generally spells a recipe for oscillation? arg Tough crap, not taking them out, they sound too good.


----------



## AmarokCZ

qusp said:


> I wouldnt trust all the numbers on the front page. for the GBW numbers they give
> [size=9pt]110 MHz gain bandwidth (G = 1000)[/size]
> [size=9pt]8 MHz bandwidth (G = 10)[/size]
> which doesnt make any sense, negative feedback as a process uses up gain to extend bandwidth and vice versa, feedback used to increase voltage gain will LOWER bandwidth, so the bandwidth for G=10 above should be higher, not lower than the bandwidth for G=1000. i'm not the first to mention this error either.


 
  That's not an error, that statement is correct, Analog Devices staff are not so silly.
  110/10=11MHz so 8MHz is jus OK since no opamp is ideal.
   
  Quote: 





leeperry said:


> That reminds me of me raving about the AD797B as I/V and LT1028AC as buffer on the HD2...


 
  LT1028 shouldn't be used as buffer without further compensating: see datasheet page 7 - figure "Gain, Phase vs. Frequency" (top middle).
  The phase curve crosses 0° sooner than gain curve crosses 0dB. For stable operation there should be a phase margin of ~45°.


----------



## WiR3D

I have a question. A stupid question but humour me.
 Opamps sound different in different conditions right, so if they sound great in non-ideal conditions and oscillate and start damaging the circuit, and then you compensate them correctly and all the components are happy, could it sound vastly different and even bad?


----------



## qusp

Quote: 





amarokcz said:


> That's not an error, that statement is correct, Analog Devices staff are not so silly.
> 110/10=11MHz so 8MHz is jus OK since no opamp is ideal.
> 
> LT1028 shouldn't be used as buffer without further compensating: see datasheet page 7 - figure "Gain, Phase vs. Frequency" (top middle).
> The phase curve crosses 0° sooner than gain curve crosses 0dB. For stable operation there should be a phase margin of ~45°.


 
  so you claim that lower gain has lower bandwidth? that certainly goes against every other datasheet or reference ive read, or build manuals i've used, thats the point, gain uses bandwidth or do you think they are not quoting gain bandwidth in the second line? it didnt make sense to me that an error would stand for this long either, but I found references to this going back 6 years including some confusion by the designer of the lisa III it also doesnt match the rest of the datasheet.
   
  i'm open to all of us being confused though, but I do wish there was some consistency in datasheets between manufacturers
   
   
  first link that came up, at ecircuit center, so there is something in the way the DS is layed out, or the way i'm interpretting it thats odd
    
  Quote: 





> Quote:  [size=medium]GAIN-BANDWIDTH-PRODUCT[/size]
> The term *fu* is also called the the *Gain-Bandwidth-Product (GBP)*. Why call it this? If we rearrange the above equation, we get
> 
> 
> ...


----------



## zilch0md

Qusp,
   
  Quote: 





qusp said:


> zilch0md, get yourself a cheap ebay thermal camera, or heat sensor and find out exactly what temp they are running, add some for the thermal impedance of the opamp package to opamp die and check the datasheet for SOA (safe operating area) wrt temp.
> 
> [snip]
> 
> if you can get the temp right down, not just of the case, but the opamp die itself, you may not kill the amp, but as is you will be shortening the life of the chips and all of the caps surrounding them. is the amp DC coupled? (no caps on the output) if it is, if they fail open or less than gracefully, you could feed the DC rail voltage directly to the headphones


 
   
  You wrote this four days ago - well ahead of my e-mail to iBasso.  Cheers!
   
  What is "a heat sensor" (in the context quoted)?
   
  Thanks,
   
  Mike


----------



## kiteki

Thanks for the interesting posts I have to catch up on, some quick questions...
   
   


> Originally Posted by *qusp* /img/forum/go_quote.gif
> 
> [/] the blinkered chase for high slew rate and wide bandwidth at all costs is not all that relevant for our purposes


 
   
  You mean like horse blinkers?  The OPA2111KP seems pretty popular and I like it, IIRC it has a pretty low slew rate.
   
   


leeperry said:


> You don't become an EE overnight basically. You may wanna have a look at this document, especially regarding AD797: http://e2e.ti.com/support/amplifiers/precision_amplifiers/w/design_notes/upgrading-op-amps-in-audio-equipment.aspx


 

   
  Interesting list, how come the 1611 and 827 aren't very popular?
   
   


leeperry said:


> That reminds me of me raving about the AD797B as I/V and LT1028AC as buffer on the HD2.......killer SQ considering that it's using the AK4396 "miracle DAC" w/ two discrete clocks for 44.1/48kHz multiples


 
   
  What's the HD2?  I sortof like the sound of AK4396 -> LT1028...


----------



## AmarokCZ

Quote: 





wir3d said:


> I have a question. A stupid question but humour me.
> Opamps sound different in different conditions right, so if they sound great in non-ideal conditions and oscillate and start damaging the circuit, and then you compensate them correctly and all the components are happy, could it sound vastly different and even bad?


 
   Depends what is bad for you, because everyone has different taste, many people likes intentionally induced distortion (and instable amp is more distorting)
  Sure thing is that this condition is bad for the circuit and it's against basic philosophy.
   
  Quote:


qusp said:


> so you claim that lower gain has lower bandwidth? that certainly goes against every other datasheet or reference ive read, or build manuals i've used, thats the point, gain uses bandwidth or do you think they are not quoting gain bandwidth in the second line?


 
  Yes, lower gain certainly doesn't have lower bandwith.
  On first line there is GBP at x1000 gain = 110MHz
  Second line is just -3dB bandwith (not GBP) at x10 gain which is stated as 8MHz that means the GBP would be 80MHz.
   
  It surely is odd and confusing since the first line is GBP and second line isn't, but it's not an error.


----------



## qusp

Quote: 





zilch0md said:


> Qusp,
> 
> 
> You wrote this four days ago - well ahead of my e-mail to iBasso.  Cheers!
> ...


 
   
  yeah, I did didnt I hehe. ibasso's claim that buffers dont need bypass caps and that multiple AD797 used as a buffer is a good idea, with the only limit being the current, is confusing for such a technology company, i'd say the person who replied only looked as far as the line that says its unity gain stable and may not have actually used the chip.
   
  the fact its in a FB loop doesnt mean its all of a sudden another opamp, we have demonstrated that it is proven mathematically to be unstable. Even chips designed to be buffers should have the rails bypassed/decoupled individually, they should also really have current sharing resistors. When all connected in parallel, there will be a tendency for some to hog the current more than others.
   
  there is a reason Walt Jung stopped recommending AD797 for his super regulators, even though when stable its still pretty hard to beat even today. its plain to me they are not happy and they should not even be considered for this application in the first place, so continuing along this track even now seems ridiculous to me
   
  as for the sensor, I mean not a camera, just an infrared heat sensor/thermometer rather than a camera if you want to save a bit. I cant find the link to the cheap thermal cameras I had, most on ebay are OTT for this, but the above will do
  Quote: 





kiteki said:


> Thanks for the interesting posts I have to catch up on, some quick questions...
> 
> 
> 
> ...


 
   
  yes Horse blinkers, its a figure of speech, ie. pushing ahead at speed without looking around. The problem is, often massive slew rate is chased while thinking of it somehow being meaningful to having a responsive amp at audio frequencies, wide bandwidth and high slew rate are good indicators that the chip will be sensitive to layout and other conditions. These types will often need a lot of NFB and heavy compensation to be stable at low audio bandwidth, low gain applications, so any advantage can easily be lost.
   
  if you like LT1028 in this application and arent able to check performance, try buffering or following it with a discrete follower, I like mosFETs, but some of the modern bipolars and definitely the power jfets are superb. I dont know why its not more popular either, personally I love opa827 and IMO its one of if not the best voltage feedback opamp for Dac IV stages, because of its stupidly low noise, high impedance jfet input stage and incredible AC performance, VERY low input bias current, which makes it great for the input of DC coupled circuits.
   
  the opa1611 wont be very good without a buffer, has bugger all current, same with the opa1641, great chip and I love jfet opamps, but its like they forgot the output stage on this one, simply pissweak output power, so would need a buffer. I keep coming back to the lme49990 and I do like the 827 a lot, just dont have enough of them to throw around and its not a cheap one
   
  IV stages are a bit of a different case, here I would champion the use of a very fast current feedback opamp designed for video mostly, as the glitch energy of delta sigma type dacs in particular is at very high speed, but you cant just drop current FB chips in place of voltage FB.
  Quote: 





amarokcz said:


> Yes, lower gain certainly doesn't have lower bandwith.
> On first line there is GBP at x1000 gain = 110MHz
> Second line is just -3dB bandwith (not GBP) at x10 gain which is stated as 8MHz that means the GBP would be 80MHz.
> 
> It surely is odd and confusing since the first line is GBP and second line isn't, but it's not an error.


 
   
  yeah youre right, the numbers make sense with that in mind, but its sure an odd way to present the info and has fooled smarter men than me. I just glanced straight past that as both being GBP until looking at it again when writing that reply above


----------



## zilch0md

qusp,
   
  Quote: 





qusp said:


> yeah, I did didnt I hehe. ibasso's claim that buffers dont need bypass caps and that multiple AD797 used as a buffer is a good idea, with the only limit being the current, is confusing for such a technology company, i'd say the person who replied only looked as far as the line that says its unity gain stable and may not have actually used the chip.
> 
> the fact its in a FB loop doesnt mean its all of a sudden another opamp, we have demonstrated that it is proven mathematically to be unstable. Even chips designed to be buffers should have the rails bypassed/decoupled individually, they should also really have current sharing resistors. When all connected in parallel, there will be a tendency for some to hog the current more than others.
> 
> ...


 
   
  Just today, I received another e-mail from iBasso in response to my asking if the PB2 is DC coupled:
   
  Quote: 





> Date: Thu, 14 Jun 2012 01:00:25 +0800
> From: iBasso Audio <service@ibasso.com>
> Subject: Re: Questions about use of AD797 in buffer stage of PB2
> ----------------------------------------
> ...


 
   
  Forgive me, but I don't understand this well enough to even tell if what iBasso has written here conflicts with what you've written above.   Please comment - I trust you!
   
  Meanwhile, I've taken the plunge and ordered one of these - just so that I can answer iBasso's outstanding question:  "How hot are the AD797s?"  
   

   
*Raytek MT6 Non-contact MiniTemp Infrared Thermometer *
   
           Temperature range: -30º to 500ºC
   
  (This is identical to the Fluke 62, but sells for about half as much.)
   
  I'm not hell-bent on using the AD797s, but I am intensely curious as to what iBasso will say when I report the temperature, and I figure I can find other reasons for this tool - like telling from a distance whether or not my wife is having a hot flash!  
	

	
	
		
		

		
		
	


	




  
   
  No, seriously, I intend to use it for comparing op-amp running temps to the operating ranges given in their datasheets.  Doh!
   
  I'm currently using HA5002s in the buffer stage (instead of AD797s or dummy buffers), along with the OPA1612s in L/R - and everything is running cool.   (How cool?  I will soon know...)
   
  Thanks again for all your tutelage,
   
  Mike


----------



## kiteki

qusp said:


> yes Horse blinkers, its a figure of speech, ie. pushing ahead at speed without looking around. The problem is, often massive slew rate is chased while thinking of it somehow being meaningful to having a responsive amp at audio frequencies, wide bandwidth and high slew rate are good indicators that the chip will be sensitive to layout and other conditions. These types will often need a lot of NFB and heavy compensation to be stable at low audio bandwidth, low gain applications, so any advantage can easily be lost.
> 
> if you like LT1028 in this application and arent able to check performance, try buffering or following it with a discrete follower, I like mosFETs, but some of the modern bipolars and definitely the power jfets are superb. I dont know why its not more popular either, personally I love opa827 and IMO its one of if not the best voltage feedback opamp for Dac IV stages, because of its stupidly low noise, high impedance jfet input stage and incredible AC performance, VERY low input bias current, which makes it great for the input of DC coupled circuits.
> 
> ...


 
   
  What's a discrete follower?  What are the intricate differences between jfet, difet, mosfet?  When driving headphones directly, do op-amps have different output impedance levels?  I can't find them in the datasheets.


----------



## qusp

Quote: 





zilch0md said:


> qusp,
> 
> 
> Just today, I received another e-mail from iBasso in response to my asking if the PB2 is DC coupled:
> ...


 
  ok mate, no worries, I reckon i'd be pretty curious too by this stage. Being DC coupled is a good thing for audio, particularly headphones as output caps tend to need to be large to allow driving low impedance headphones without rolling off the bass. they form a high pass filter at the output in combination with the headphone impedance and the amps output impedance (I will call impedance Z from now on). Electrolytics are not so linear and have lower damping factor (means high output Z) so the amp does not have quite as good electro-mechanical control of the driver, not such an issue with headphones some would say, due to being physically small, but I disagree.
   
  DC coupling is not without its caveats though, the output caps help to protect the headphones from DC at the output if the amp, so the fact its a DC coupled amp, means although audio performance is good, if there is a failure condition in the amp that creates DC your headphones will see all of it.
   
  indeed the temp sensor is handy for all sorts of things and most are pretty cheaply priced, so you didnt buy the fluke? would have been risky on ebay, fluke gear on the bay is often fake, as its a well known big brand.


----------



## kiteki

Quick question if anyone can answer on the PCM5102.
   
   

 *Feature* *02US* *03US* *02 Dragon* *Comparison*                               DAC PCM1793DNR: 113 dB
 THD: 0.001% PCM1798DNR: 123 dB
 THD: 0.0005% PCM 5102DNR: 112 dB
 THD:0.0022%   I/V OP275 MC33079 This is a voltage-out DAC so there is no need of I/V conversion
   
   
  The Teac / Esoteric A-H01 uses this D/A chip as well.  However it doesn't have an RCA or COAX line-out (the UD-H01 has line-out, in dual-mono with 2x PCM1795).
   
  So my question is... is the Dragon an ideal USB DAC for connecting to amplifiers via RCA, to experiment with op-amps in the amplifier section, or am I overlooking something?  Clearly a conventional DAC with I/V will potentially colour the experiments right?
   
  Likewise, the Teradak 2.6 has passive I/V - http://www.teradak.com/en/product_view.asp?ID=206
   
  I see portable devices like the Teclast T51 using OPA2604 for the 'line-out', is this standard or are there portable devices with true direct signal from the D/A?


----------



## zilch0md

Quote: 





qusp said:


> ok mate, no worries, I reckon i'd be pretty curious too by this stage. Being DC coupled is a good thing for audio, particularly headphones as output caps tend to need to be large to allow driving low impedance headphones without rolling off the bass. they form a high pass filter at the output in combination with the headphone impedance and the amps output impedance (I will call impedance Z from now on). Electrolytics are not so linear and have lower damping factor (means high output Z) so the amp does not have quite as good electro-mechanical control of the driver, not such an issue with headphones some would say, due to being physically small, but I disagree.
> 
> *DC coupling is not without its caveats though, the output caps help to protect the headphones from DC at the output if the amp, so the fact its a DC coupled amp, means although audio performance is good, if there is a failure condition in the amp that creates DC your headphones will see all of it.*
> 
> indeed the temp sensor is handy for all sorts of things and most are pretty cheaply priced, so you didnt buy the fluke? would have been risky on ebay, fluke gear on the bay is often fake, as its a well known big brand.


 
   
  Thanks qusp - I'm more convinced than ever that, using a DC coupled amp like the PB2, I don't want to risk the use of unstable op-amps.
   
  Regarding Fluke 62 vs. RayTek MT6 - I found a couple of Fluke 62 reviews which say that the Fluke 62 is just a re-branded RayTek MT6 - they truly are identical except for color and branding.  
   
  I picked up the RayTek for $52.00 instead of $86.00 for the Fluke.
   
   

   
   
                           $86.00                                                                $52.00
   
   
  Mike


----------



## viveksaikia22

I have a iBasso D-12 and a iBasso D12 with the topflight kit. I am interested in OPAmp rolling and try out the different sound.
  I find the high freq response of the D-Zero better than the D-12 stock OPAmp.
  Does anyone knows what OPAmp is used the D-Zero.
  Also, is there any list of compatible OPAmps with the iBasso D-12?


----------



## kiteki

D-Zero is AD8656.  I recommend you try a few AD chips until you find one of your liking.  You can start here.


----------



## qusp

kiteki, saw your Q, no time to answer till tonight


----------



## viveksaikia22

Quote: 





kiteki said:


> D-Zero is AD8656.  I recommend you try a few AD chips until you find one of your liking.  You can start here.


 
  Thanks for the information and the recommendation. Ordered a AD712KN right away without checking if it a dual or single channel OPAMP


----------



## Mad Max

Quote: 





viveksaikia22 said:


> I have a iBasso D-12 and a iBasso D12 with the topflight kit. I am interested in OPAmp rolling and try out the different sound.
> I find the high freq response of the D-Zero better than the D-12 stock OPAmp.
> Does anyone knows what OPAmp is used the D-Zero.
> Also, is there any list of compatible OPAmps with the iBasso D-12?


 
   
  Check the D12 and D10 threads, there's plenty.  Most require soldering, if I recall correctly.


----------



## qusp

Quote: 





mad max said:


> Check the D12 and D10 threads, there's plenty.  Most require soldering, if I recall correctly.


 
   
  yeah well they dont really make dip8 any more in new models, not for a while now


----------



## Mad Max

That's why many chips require soldering to adapters.  Otherwise, you are left with DIP8 chips, some of which are meh, some are super fast video opamps with a lot of need for compensation and whatever else.  I wouldn't complain about OPA602, neat chip, but probably not such a good buffer with only 20ma output.


----------



## genclaymore

If only alot of the one that was mention came in dip-8 vers.That way I don't have to send them off to get them soldered.


----------



## kiteki

Is there any reason why a class-A biased OPA627 with some silly resistors would sound worse than a regular OPA627?  I don't like it.
   
  When the PDF says absolute max +-18V that's 4x 9V batteries right?  What happens if I overclock the OPA627 to +-19.2V?


----------



## AmarokCZ

1) All (well, maybe not all, but most) OA perform better when not loaded. Biasing in class A is load, so it could sound worse (depends on the value of that bias resistor = biasing current)
  2) Yes, +/-18V = four 9V batteries. If you "overclock" it to +/-19.2V nothing serious would propably happen (it could perform worse, but to burn it you need much higher voltage).


----------



## kiteki

Thanks for the swift answers Amarok!!  The loaded OPA627 doesn't sound very good.  I will experiment with voltage supply in OPA627 and OPA827 to see if I can hear the difference!
   
  Edit:  My amplifier won't turn on when 4x 9V are connected.


----------



## qusp

Quote: 





kiteki said:


> Quick question if anyone can answer on the PCM5102.
> 
> 
> 
> ...


 
   
  I think you are misunderstanding the term line out. line out simply means line level voltage output, just a reference level voltage so that engineers know they arent going to blow or clip the input of their amps or mixers as they know what to expect. it has nothing to do with whether there is a circuit in the output and an IV convertor is simply there to give that standard level from a current output. this could be a simple resistor, a discrete jfet IV, or transformers along with many other types.
   
  the above quoted specs I wouldnt take anything from the above, the 3 dacs have just taken the ideal datasheet performance from the dac chip, nothing to do with its performance in the application.
   
  the below is a table for the line level single ended standard. in reality dacs are all over the place, the sabres balanced out for instance is about 3vrms @ 3.9ma which is about double the +6db SE standard, so pretty hot voltage, but lower than normal current.
   
  Some current out dacs will handle passive resistive IV well, depending on their voltage compliance and current, others will not handle it well at all, with the sabre the THD+N is not great with passive IV, but some still prefer the sound. I personally dont like passive IV all that much; its a bit musical for my taste, top end lacking sparkle, easy to listen to, but for me dynamics are compromised, at least with the dacs i've tried it with.
   

 Use Nominal level Nominal level, VRMS Peak Amplitude, VPK ARD, Germany +6 dBu 1.550 (approximate) 2.192 (approximate) USA professional audio +4 dBu 1.228 (approximate) 1.737 (approximate) Consumer audio −10 dBV 0.316 0.447
  Line levels and their nominal voltage levels.     
  the voltage out dacs, like the one you mention and wolfstons, should be buffered, not connected directly, they should not be loaded with capacitive cables etc and usually have an internal opamp anyway. so if you just have a well designed transparent IV stage that you leave constant during the tests, then this is just as valid as a baseline.
   
  I generally prefer current out dacs as I like maintaining control of the IV stage, but i'm quite intrigued by the AK4399, so have picked up a couple of chips and a suitable proto board


----------



## qusp

most high performance opamp output stages these days are already pretty deeply biased, so with nominal load should be in class A anyway. It depends on the load, driving low impedance headphones directly would take most out of the class A envelope without extra bias, so it can be useful
   
  I would be more likely to use a current source than a resistor anyway, like a jfet CRD, or a jfet wired as current source, this creates a much higher impedance current source so the noise on the PSU rail isnt injected directly.
   
  not a fan of the adapters, they are a necessary evil though.
   
  as for your batteries, realize that the voltage is a nominal rating, probably they start very slightly higher, spend most of their time around 9.4-9.6 and then drop down as they run out, depends on the chemistry what this curve will look like. probably the positive rail will drop much quicker, so watch that.


----------



## qusp

Quote: 





kiteki said:


> Thanks for the swift answers Amarok!!  The loaded OPA627 doesn't sound very good.  I will experiment with voltage supply in OPA627 and OPA827 to see if I can hear the difference!
> 
> Edit:  My amplifier won't turn on when 4x 9V are connected.


 
  how exactly have you connected them? have you taken the center tap (ground reference) from the middle, or just connected the 4 in series and connected across it?


----------



## kiteki

Like that.


----------



## kiteki

I could smell something burning, lucky it was an empty saucepan in the kitchen ^^


----------



## AmarokCZ

*qusp*: depends whats "pretty deeply biased" for you - OPA627 has 7mA quiescent current, whole OA is biased in class A except output stage which is AB class and there is not much current left for this stage. Not sure where I saw it, but I think someone (at DIYAudio ??) measured quiescent current of output stage of OPA627 ant it was ~0.5mA.
*kiteki*: six 9V batteries?? Whats on the other end of those wires?  
	

	
	
		
		

		
			





  BTW you should also add third wire - ground!


----------



## zilch0md

Kiteki,
  Quote: 





kiteki said:


> Is there any reason why a class-A biased OPA627 with some silly resistors would sound worse than a regular OPA627?  I don't like it.
> 
> When the PDF says absolute max +-18V that's 4x 9V batteries right?  What happens if I overclock the OPA627 to +-19.2V?


 
   
  I'm not the thread guru, by a long shot, but I'm pretty sure that the +-18V absolute supply voltage spec is reached with only two 9V DC batteries in series, NOT four.  And, except for so-called rail-to-rail op-amps, where output voltage is nearly as high as supply voltage, most datasheets will show performance curves that are limited to a supply voltage no higher than 15V - because the op-amp sounds better when operating at something LESS than the absolute maximum allowable supply voltage.
   
  The Meier Audio Stepdance, for example, uses OPA1611s, rated with an absolute maximum supply voltage of +-18V, but its designer documents that external power supplies should be limited to 15V DC. 
   
  The iBasso PB2 can be used with various op-amps, but its designer documents that external power supplies should be limited to 16V DC.  The iBasso's internal battery is only 12.6V when fully charged - it's a 3-cell Lithium-ion pack (4.2V per cell, when fully charged).
   
  The RSA SR71B's internal battery is only 16.8V when fully charged - it's a 4-cell Lithium-ion pack.
   
  I really don't think you should use the 36V serial battery (your first picture, above).   I realize that the 54V pack was meant to be a joke.  
	

	
	
		
		

		
		
	


	



   
  Comments from anyone else?
   
  Thanks,
   
  Mike


----------



## WiR3D

Quote: 





> Originally Posted by *qusp* /img/forum/go_quote.gif
> 
> _snip_
> 
> ...


 
  stupid question, Yulong Sabre?
   
  @kiteki
  sounds like something a few engineering buddies did, but it involved charging a rather large cap with every battery in the class, and then smacking it onto a switchboard. Ever heard of a University laboratory tripping? Yeah me neither until then.


----------



## qusp

Quote: 





zilch0md said:


> Kiteki,
> 
> I'm not the thread guru, by a long shot, but I'm pretty sure that the +-18V absolute supply voltage spec is reached with only two 9V DC batteries in series, NOT four.  And, except for so-called rail-to-rail op-amps, where output voltage is nearly as high as supply voltage, most datasheets will show performance curves that are limited to a supply voltage no higher than 15V - because the op-amp sounds better when operating at something LESS than the absolute maximum allowable supply voltage.
> 
> ...


 

 no, to get +/-18 you need 4 or 8 ~9v batteries (8 for a 2P4S, 4 for 4S) but the point between 2->3 is your ground reference so you have  +18v[+9v-] -> [+9v-] -0/G- [+9v-] -> [+9v-] -18v   , since that ground connection is missing youve just connected 36v across the opamp but with no ground its got nowhere to go, so wouldnt have damaged anything. sorry *zilch0md *hes done it exactly right, just missing ground.if it has to be batteries then he hasnt got much choice but +/-9v or +/-18v unless he wants to do a 3 channel (I think this would be silly) or rail splitter (also silly given hes got the cells to do a real return.
   
  @AmarokCZ: I didnt look at the 627 datasheet at all and havent used one in ages, I was talking more generally. I thought it would be deeper than that though, since so many people use it basically as a buffer. the dedicated buffer chips are much better in this regard, for instance that paralleled buffer amp I posted is in class A for a decent chunk of its 15w output into expected loads. I cant remember how much exactly from memory.
   
  not that modern class AB is bad mind you, as long as the PSU is up to it (Class AB is actually much harder on PSUs than Class A for others reading, due to the constant power draw of class A; regardless of load currents)


----------



## kiteki

Thanks for the responses AmarokCZ, qusp, WiR3D, zilch0md, viveksaikia212.  I've had a LOT of fun tonight, first with really successful results with my first DIY amplifier, and then really successful results with an IEM modification too! http://www.head-fi.org/t/614513/jvc-fx500-yellow-filter-black-filter-and-cotton-removal-review
   
  I couldn't actually hear much difference in this experiment from 2 batteries to 6, and I only used OPA552 with 6 batteries since it can safely handle +-27V.  AD797 and OPA627 at +-18V seem to sound pretty nice though.  My favorite line tonight was with AK4396 -> OPA827 (in the DAC) -> buffer -> OPA627 (+-18V) -> IEM's.
   
  Oh, I overlooked my new MUSES!  Time to put that one in, continue drinking alcohol and just enjoy the music! =)


----------



## zilch0md

Qusp,
   
  Quote: 





qusp said:


> no, to get +/-18 you need 4 or 8 ~9v batteries (8 for a 2P4S, 4 for 4S) but the point between 2->3 is your ground reference so you have  +18v[+9v-] -> [+9v-] -0/G- [+9v-] -> [+9v-] -18v   , since that ground connection is missing youve just connected 36v across the opamp but with no ground its got nowhere to go, so wouldnt have damaged anything. sorry *zilch0md *hes done it exactly right, just missing ground.if it has to be batteries then he hasnt got much choice but +/-9v or +/-18v unless he wants to do a 3 channel (I think this would be silly) or rail splitter (also silly given hes got the cells to do a real return.
> 
> [snip]


 
   
  More confused than ever...
   
  So, does this mean that if my PB2 is equipped with op-amps rated for an absolute supply voltage of +- 18V, I can feel free to connect a 36VDC external power supply?  
   
  I suspect you will answer, "No," but I don't understand why you will say, "No" other than to advise me to stick with the manufacturer's recommendation to not exceed 16V DC at the external supply jack.
   
  Mike
  (the villiage idiot)


----------



## SpudHarris

Mike, there are other components in there that may limit what you can safely pump in.


----------



## zilch0md

Quote: 





spudharris said:


> Mike, there are other components in there that may limit what you can safely pump in.


 
   
  Thanks Nigel,
   
  I can readily imagine that's true, and would not want to exceed the manufacturer's documented maximum permissible external supply voltage, but I was hoping to gain an understanding of how it is that kiteki can use 36V DC battery packs to supply power to op-amps that have the same +-18V absolute maximum Vs rating as many of the op-amps that I use (including the AD797 - which we both use).  
   
  I have no problem understanding that a swing from -18V to +18v is 36V (doh!), but does this mean that if kiteki were to use only two 9V batteries in series (for a total of 18V) instead of four 9V batteries (for a total of 36V), kiteki's op-amps would only be getting HALF their maximum permissible supply voltage?  If the answer to that question is, "Yes," then does this mean that when I use a 16V external DC battery pack with my PB2, I'm only getting a swing of -8V to +8V, which is less than HALF of my op-amps' maximum permissible +-18V supply voltage?   I don't think so.  Here's why:
   
  Jan Meier once told me that the Meier Stepdance uses a "voltage doubler" that will take an internal 9V battery up to 18V or an external 15V supply voltage up to 30V.
   
  Maybe that's what's going on with the PB2, also - when I connect a 16V external power supply, the op-amps see 32V because of some sort of voltage doubling circuit - and maybe kiteki's amp doesn't have this voltage-doubling feature...
   
  Mike


----------



## kiteki

I'm not aware of any volting doublage, though I am interested in one since I can't fit 4x 9V batteries in a portable amplifier lol.
   
   
Do not put a class-A biased OPA627 in the wrong way, I turned on the DAC and it looked like it was going to catch on fire.
   
  Edit:  Threw away the chip all fixed.


----------



## AmarokCZ

Two 9V batteries means only +/-8V, so approx. half of maximum voltage.
  It seems that IB2 has an voltage inverter to make neagative supply (-16V) from positive external supply (e.g. on PCB there is one compoment that looks like MOSFET - this would be inverters switching transistor).


----------



## qusp

Quote: 





zilch0md said:


> Qusp,
> 
> 
> More confused than ever...
> ...


 
   
  that depends on how the power supply is handled, or more specifically, how the ground reference is generated and; as covered, whether there is any type of DC switching/upconverting performed to boost voltage, or generate the negative rail voltage. of course if the manufacturer says not to exceed 16vdc, do not exceed 16vdc, they will have reason for saying this.
   
  the use of a voltage doubling circuit is not all that common in high end headphone audio, even portable. 1. because it is a process that generates noise, mostly switching noise (out of band noise, but noise all the same) 2. it means a virtual ground is created and this is higher impedance than a real split supply 3. most headphones are perfectly happy with the swing available from +/-8-9vdc rails, with only 600ohms needing more IMO. for instance in my portable balanced dac-.amp i'm 'only' running a 4 series connected A123 LiFePO4 for a total of +/-6v6->7vdc, this is regulated down to +/-5.9vdc with a dual mono/bipolar supply and I challenge anyone to go past 60% with HD600. these batteries are capable of 140A bursts, thus I dont use them directly lol even though their noise and output impedance is lower than the regulators (2 x LTC3032)
   
  Jan has some clever tricks in the stepdance overall, but i'd rather balanced than pseudo balanced and i'd rather bipolar rather than pseudo bipolar, both mechanisms introduce noise and impedance
  Quote: 





spudharris said:


> Mike, there are other components in there that may limit what you can safely pump in.


 
   
  what he said
  Quote: 





zilch0md said:


> Thanks Nigel,
> 
> I can readily imagine that's true, and would not want to exceed the manufacturer's documented maximum permissible external supply voltage, but I was hoping to gain an understanding of how it is that kiteki can use 36V DC battery packs to supply power to op-amps that have the same +-18V absolute maximum Vs rating as many of the op-amps that I use (including the AD797 - which we both use).
> 
> ...


 
   
  I think kiteki is playing with the output stage of his dac, arent you? but yeah everything else is covered above. i've not looked at the pelican PSU, I really dont see the need for +/-16v, but hey...
  Quote: 





kiteki said:


> I'm not aware of any volting doublage, though I am interested in one since I can't fit 4x 9V batteries in a portable amplifier lol.
> 
> 
> Do not put a class-A biased OPA627 in the wrong way, I turned on the DAC and it looked like it was going to catch on fire.
> ...


 
   
  haha yeah batteries will do that, no current limiting


----------



## qusp

Quote: 





wir3d said:


> stupid question, Yulong Sabre?


 
   
  nope, fully DIY 2 x Ackodac AKD12P, with various additions and it leaves the Yulong in the dust. well some is kit stuff, some i've started with blank PCBs and some parts i've built from scratch like the pre-regs and soon to be MCU. with the i2s fifo and titan USB-i2s convertor, its up there with 5 figure dacs and so it should be, by the time i'm done there'll be about 5k into the project and a lot of time. this is for a 4 channel and soon to be 6 channel balanced sabre (tri differential with a sabre for each Bass, Mid, Tweeter and matching amps, not using the 8 channels in the 9018) ive got about the same into the amps and speakers.
   
  i'm not trying to save money, just build something that cannot be bought, built to taste, as well as having some fun and learning along the way.


----------



## kiteki

qusp said:


> IV stages are a bit of a different case, here I would champion the use of a very fast current feedback opamp designed for video mostly, as the glitch energy of delta sigma type dacs in particular is at very high speed, but you cant just drop current FB chips in place of voltage FB.


 
   
  I'll try some video op-amps soon, after XX hours of listening the LT1028, OPA827 and MUSES are the current favorites in my DAC I/V stage.  It's difficult to know which one is the most revealing, and if I was blind evaluating the MUSES I suspect I'd completely overlook it.
   
   


qusp said:


> I think you are misunderstanding the term line out. line out simply means line level voltage output, just a reference level voltage so that engineers know they arent going to blow or clip the input of their amps or mixers as they know what to expect. it has nothing to do with whether there is a circuit in the output and an IV convertor is simply there to give that standard level from a current output. this could be a simple resistor, a discrete jfet IV, or transformers along with many other types.
> 
> the above quoted specs I wouldnt take anything from the above, the 3 dacs have just taken the ideal datasheet performance from the dac chip, nothing to do with its performance in the application.
> 
> ...


 
   
  I don't think the PCM5102 has an internal op-amp like the ES9023, or it wouldn't be called voltage-out, or am I missing something?
   
  While your repy was helpful, thanks, my wave of thought is on a purist perspective.  For example in my Teclast T51 the 'line-out' has OPA2604, I don't want that horrible chip there colouring the sound in my experiments, I need a 'pure' line-out, even if only in theory.  As you can see in my JVC FX500 modification I like removing filters from the signal, digital and acoustic.
   
  In short I'm considering the Musiland Dragon, TeraDak 2.6 and Colorfly CK4 right now, I just don't have the technical experience to know if these are the right choices for my 'line-out' experiments and listening!
   
   
   


qusp said:


> I think kiteki is playing with the output stage of his dac, arent you? but yeah everything else is covered above. i've not looked at the pelican PSU, I really dont see the need for +/-16v, but hey...
> 
> haha yeah batteries will do that, no current limiting


 
   
  The toasted OPA627 was in my DAC.  The 9V batteries in 2x, 4x, 6x are connected to a DIY portable amplifier.


----------



## qusp

Quote: 





> I don't think the PCM5102 has an internal op-amp like the ES9023, or it wouldn't be called voltage-out, or am I missing something?


 
  yep, youre missing something es9023 is a 'voltage out' chip too. you havent mentioned a single current out dac. still dont think you get it, these things are all made from tiny little fets and transistors among other features and to provide a somewhat stiff output with decent voltage compliance and to set the correct voltage level, there is a circuit which is loosely called an opamp.
   
  voltage is higher noise than current transfer, it would be pretty odd for a manufacturer to use voltage feedback in a dac rather than current feedback and the easiest and best measuring way to convert current to voltage and set the level is an opamp. this isnt a modern initiative either, its been that way for years.


----------



## kiteki

The common perception is to use LOD to bypass the amplifier, and that the signal is sent directly from the DAC.
   
  The TeraDak has "passive I/V" and the Lite-Dac AH uses AD847, one uses op-amps - the other doesn't - so no I still don't get it...


----------



## Avro_Arrow

Your chasing a ghost...
  Any DAC, whether current out or voltage out, still requires a low pass filter to keep the high frequency "junk" from
  making it through to the amp. You might think that the fewer components after the DAC the better, but only to a point.
   
  I think the quote from Albert Einstein says it best..."Make things as simple as possible, but not simpler."
   
  Even the PCM5102 (which puts the I/V stage on the chip) recommends a low pass filter on the output.
   
  Quote: 





kiteki said:


> The common perception is to use LOD to bypass the amplifier, and that the signal is sent directly from the DAC.
> 
> The TeraDak has "passive I/V" and the Lite-Dac AH uses AD847, one uses op-amps - the other doesn't - so no I still don't get it...


----------



## AmarokCZ

Quote: 





avro_arrow said:


> Your chasing a ghost...
> Any DAC, whether current out or voltage out, still requires a low pass filter to keep the high frequency "junk" from making it through to the amp....


 
  No one DAC strictly requires low pass filter, but apparently for most designers (and especially for "analog people") it's more acceptable when sine wave looks really like sine wave and not like that "sine" on my avatar (which actually is a sine wave from DAC without low pass).
  For example NOS DACs usally don't use low pass filters (or just some simple RC filter to round off the edges, but it still don't look like a sine).


----------



## qusp

Quote: 





kiteki said:


> The common perception is to use LOD to bypass the amplifier, and that the signal is sent directly from the DAC.
> 
> The TeraDak has "passive I/V" and the Lite-Dac AH uses AD847, one uses op-amps - the other doesn't - so no I still don't get it...


 
   
  the common perception is wrong...
   
  the teradak is compromised IMO, it is designed for tweakers, with plenty of space so they can install huge film caps and boutique resistors where a proper output stage should be =) i'm of the opinion that while you can make something half decent if you basically replace everything in it, there is no water into wine. as TDA's go, this chip is entry level only and the PCB layout, particularly the digital and power supply section is ....not ideal.
   
  you cannot build that type of thing point to point with patch wires and expect high performance, if you want a decent dac, build or buy a decent dac from the ground up. some designs are basically good designs that could use a bit of a helping hand, but the layout, parts choice and grounding of this simply cannot be undone. sure its a bit of fun and some people have done some interesting things with these dacs, but there is a point where the layout itself hampers efforts.
   
  yes i'm opinionated, some will disagree with my view, but dacs, particularly these days of higher speeds are more akin to RF than standard analogue, so are quite sensitive to layout issues /rant
   
  Quote: 





amarokcz said:


> No one DAC strictly requires low pass filter, but apparently for most designers (and especially for "analog people") it's more acceptable when sine wave looks really like sine wave and not like that "sine" on my avatar (which actually is a sine wave from DAC without low pass).
> For example NOS DACs usally don't use low pass filters (or just some simple RC filter to round off the edges, but it still don't look like a sine).


 
  dont tell me you are a nosser too? cant get away from you damn people lol NOS simply uses the ear to act as LPF, but given how wideband many amps are nowdays i'm not sure this is enough


----------



## AmarokCZ

Nope, I'm not NOSser. But I don't think that it's bad idea to use ear as LPF, because it works and it's certainly better than oversampling combined with LPF set to -3dB@25kHz to 30kHz (which sounds terrible). I prefer high oversampling and then some LPF with low delay.


----------



## qusp

Quote: 





amarokcz said:


> Nope, I'm not NOSser. But I don't think that it's bad idea to use ear as LPF, because it works and it's certainly better than oversampling combined with LPF set to -3dB@25kHz to 30kHz (which sounds terrible). I prefer high oversampling and then some LPF with low delay.


 
   


 indeed I agree putting a filter right in the middle of the HF spacial information is dumb and all too common. your preference sounds about the same as me, I use software apodising OSF (8 x 8 x FS) which feeds a synchronously clocked ESS. that way a very high quality cap can be used pretty cheaply too.
   
  I just fret about room modes bringing some of that info that should be rolled off down into audible FR, so I prefer an actual filter


----------



## Headdie

Hi,
   
  I'm looking for advice or suggestions.
   
  My new desktop headamp is the Firestone Cute Curve,
   
  http://www.firestoneaudioproducts.com/cute-series/cute-curve/
   
  The PSU is 24V and could be raised to 30V.
   
  From the specs :
   
  Main OPAmp : TI – OPA2604
  Servo OPAmp : TI – TL072
   
  Both are in sockets.
   
  Do you think I could improve it a little with new OPAmp ?
   
  I don't know anything about it. I've read enough in this thread and elsewhere to understand that the best I can do is to ask for a little help.
   
  My phones range from Denon D2000-25ohms to Beyerdynamic DT990-600ohms. If it's relevant, I'd prefer to optimize it for mid/low impedance... I already have what it takes for high impedance cans.
   
  I listen to jazz, classical, progrock and many thing else.
   
  I don't listen loud with headphones, if it matters to op amp selection...
   
  So what do you think guys : Am I a good candidate for new opamps ? And what would you suggest...
   
  Thanks a lot,
   
  Headdie


----------



## Headdie

I've begun by ordering LME49860. I guess you have to begin somewhere...
   
  Now a basic question : Do I simply grab and pull out the opa2604 from the socket, and then push the new one in it ?


----------



## kiteki

headdie said:


> I've begun by ordering LME49860. I guess you have to begin somewhere...
> 
> Now a basic question : Do I simply grab and pull out the opa2604 from the socket, and then push the new one in it ?


 
   
  I'm not a fan of the OPA2604.  I've listened to it for over a year and tried it in my DAC, it has a little colour, it's like a neutral colour, it's deceiving you into thinking it's a nice natural sound, I saw someone call it "like red wine" once, anyway.
   
  You need to use a tool to extract the op-amp, ideally.  It's called extractor something, looks like a polygon shape with a ~1cm wide tweezer on the end.
   
  You should order more than just the LME49860.  What type of sound are you after?
   
  Will comment on the other posts later.


----------



## Headdie

Bonjour Kiteki,
   
  I'm after better sound : less noise, better fidelity and details. I'm not looking for a way color the sound.
   
  I intend to roll once with the LME49860. If it's a clear change, then I may be tempted to continue. If not, I'll probably stop there.
   
  May I roll it without the extracting tool ? I mean, is it locked in the socket somehow...
   
  Thanks,


----------



## zilch0md

Quote: 





headdie said:


> Bonjour Kiteki,
> 
> I'm after better sound : less noise, better fidelity and details. I'm not looking for a way color the sound.
> 
> ...


 
   
  With everything turned off, I just insert a narrow, flat-bladed screwdriver under the op-amp and gently twist it a little bit, going to the opposite side to do the same, then back to where I started, until I've lifted it away from the socket as high as the screwdriver blade is wide, then I just grab the package between thumb and forefinger and gently rock it the rest of the way out of the socket - being careful not to move it sideways until it is well clear of the socket - to avoid bending pins.
   
  Joy!
   
  Mike


----------



## kiteki

Did you buy a dual like this one?  http://www.ebay.com.au/itm/1PCS-Dual-Mono-LME49990MA-replace-OPA2604-NE5532-TL072-/320863640326
   
  What Mike said with a screwdriver will work.
   
  Hope you like the new sound, you won't more details, however you should find a cleaner character.


----------



## Headdie

LME49860 is already two channels...
  I've considered an opa627 dual of that sort...


----------



## kiteki

OPA827 has slightly less colour in my impartial analysis and I couple others I've seen online.


----------



## Chromako

Hiya! Newbie question (sorry to bother all of you experts, but I'm just starting to get interested in this). 
   
  A lot of the designs have only a couple op-amps. When I took a look at my Meier Corda Opera, it had 12 (!) LM6171's (socketed, which is awesome given my soldering skills, which I wouldn't trust with a $1300 unit). It is unbalanced, but has a shared active ground (if that makes any difference). 
   
  Just wondering, what sort of benefit would having so many op-amps have? Why might it have been designed with so many? Just curious.


----------



## qusp

Quote: 





chromako said:


> Hiya! Newbie question (sorry to bother all of you experts, but I'm just starting to get interested in this).
> 
> A lot of the designs have only a couple op-amps. When I took a look at my Meier Corda Opera, it had 12 (!) LM6171's (socketed, which is awesome given my soldering skills, which I wouldn't trust with a $1300 unit). It is unbalanced, but has a shared active ground (if that makes any difference).
> 
> Just wondering, what sort of benefit would having so many op-amps have? Why might it have been designed with so many? Just curious.


 
   


 honestly, I dont think you should touch it, socketed or not, his arrangement there will be to enable the psuedo balanced operation and also his crossfeed filter/effect. in these type of circuits the parameters of the opamps will have an effect on the frequency response due to differing input impedance etc. I suggest you leave well enough alone with that one.


----------



## Chromako

Quote: 





qusp said:


> honestly, I dont think you should touch it, socketed or not, his arrangement there will be to enable the psuedo balanced operation and also his crossfeed filter/effect. in these type of circuits the parameters of the opamps will have an effect on the frequency response due to differing input impedance etc. I suggest you leave well enough alone with that one.


 
  Huh. Interesting. So having so many helps enable all those cool goodies? I learned something new today! 
	

	
	
		
		

		
		
	


	



   
  Mr. Meier (or Dr?) really went all out with the design of this! Coolness.


----------



## qusp

yep, well if you ask Jan, he might be able to point out some opamps that are not part of the filter that you can toy with and maybe suggest some suitable alternatives, or he might be scathing =) dunno.
   
  I presume he socketed them for a reason, but its not going to be as straight forward as blind rolling and you may have to change 4 at a time


----------



## Avro_Arrow

For the op amp rollers...
   
Why op amps oscillate.
Taming the Oscillating Op Amp part 1.
Taming the Oscillating Op Amp part 2.


----------



## zilch0md

Thanks for the links!
   
  Mike


----------



## WiR3D

Quote: 





avro_arrow said:


> For the op amp rollers...
> 
> Why op amps oscillate.
> Taming the Oscillating Op Amp part 1.
> Taming the Oscillating Op Amp part 2.


 
  Awesum awesum stuff


----------



## qusp

nice one avro arrow, I just came here to link those new Ti articles, very comprehensive


----------



## SpudHarris

I subscribe to AD's news letter and they sent me this info today http://www.analog.com/en/all-operational-amplifiers-op-amps/operational-amplifiers-op-amps/ad823a/products/product.html
   
  I thought the AD823 was an old design? I remember Graham Slee using it in the SOLO. Yet AD are saying this is a new chip, what gives??


----------



## WiR3D

Quote: 





spudharris said:


> I subscribe to AD's news letter and they sent me this info today http://www.analog.com/en/all-operational-amplifiers-op-amps/operational-amplifiers-op-amps/ad823a/products/product.html
> 
> I thought the AD823 was an old design? I remember Graham Slee using it in the SOLO. Yet AD are saying this is a new chip, what gives??


 
  New revision, Rev B


----------



## Headdie

I've just replaced the OPA2604 by an LME49860.
   
I'm actually listening to it with a DT990-250ohms.
   
First feelings :
   
  Sounds good indeed ! Less on the dark side... I can hear many things... Music seems closer... Bass seems stronger... Or maybe it's the dynamic... Stereo separation is really there... Fact or fiction, I don't know yet...
   
  Next step : more listening, also with the D2000, and comparing against the NAD, wich is my reference...
   
  See ya tomorrow guys !
   
  Quote: 





headdie said:


> Hi,
> 
> I'm looking for advice or suggestions.
> 
> ...


----------



## Headdie

After some readings, I understand that I could roll the main op-amp (what I've done replacing the opa2604 by an lme49860), but that I should leave alone the servo op-amp (tl072), because it's not in the audible audio path... Am I mistaken ?
   
  Also, the servo tl072 is paired with the main opa2604 in the Firestone Cute Curve, but is it compatible with another op-amp like the lme49860 that I've rolled in ?
   
  After more listening, the Cute Curve with LME49860 is definitly an improvement with the DT990, but I'm still not sure with the D2000. With the DT990, it is now up to the level of my NAD, maybe even better.


----------



## WiR3D

Quote: 





headdie said:


> After some readings, I understand that I could roll the main op-amp (what I've done replacing the opa2604 by an lme49860), but that I should leave alone the servo op-amp (tl072), because it's not in the audible audio path... Am I mistaken ?
> 
> Also, the servo tl072 is paired with the main opa2604 in the Firestone Cute Curve, but is it compatible with another op-amp like the lme49860 that I've rolled in ?
> 
> After more listening, the Cute Curve with LME49860 is definitly an improvement with the DT990, but I'm still not sure with the D2000. With the DT990, it is now up to the level of my NAD, maybe even better.


 
  Arg. Build a faux impedance decreasing adapter for the D2k, it makes a much bigger difference then opamps.
  For analytical phones like AKG K240mkII its the opposite. 
   
  and try the THS4032 in the I/V, I like it for neutrality, and clarity and having no detracting factors.


----------



## kiteki

avro_arrow said:


> Your chasing a ghost...
> Any DAC, whether current out or voltage out, still requires a low pass filter to keep the high frequency "junk" from
> making it through to the amp. You might think that the fewer components after the DAC the better, but only to a point.
> 
> ...


 
   


qusp said:


> kiteki said:
> 
> 
> > The common perception is to use LOD to bypass the amplifier, and that the signal is sent directly from the DAC.
> ...


 
   
  I know these posts were over a week ago, I just wanted to note...
   
  The 'common perception' is logical.  You can construct a DAC section and amplifier section on the same circuit board, or you can construct a DAC section and amp section on two seperate circuit boards, with two enclosures surrounding them, so what is the difference?  The difference is... if you get a nice rectangular piece of circuit board and connect them again... nothing.   This is also known as a cable, unless cables have some sort of issue.
   
  So back to my situation - I'm not looking for the ultimate DAC or a DIY project right now, I just want something that doesn't have hints of colour or tint in the signal path for experimentation purposes and peace of mind.  For example if I want to try the OPA1611 versus OPA827 in my DIY amplifier, I wouldn't feel right with the Lite-DAC with 2x AD847 supplying the signal, let alone the TeraDak if it improves with film caps and fancier resistors.
   
  I know NOS sounds pretty weak compared to modern OS chips, and if you scored them in 10 different categories from 1-10 OS would_ easily _win, but NOS _does_ win in at least 1 category I am fairly certain of (via my listening, not specs), which is why it's still used today in various high-end projects.
   
  I might be chasing a ghost asking for advice on a 'pure' DAC which is just a lonely chip with nothing around it, but I hope my clarification makes sense that some DAC's are purer than others.  For the end result it may not be very important factor, but for evaluation purposes you need as little colour as possible.
   
  In other words a pre-amp might be technically better to have in some situations for the end result, but if you're building or evaluating an amplifer you don't want a weak sounding pre-amp supplying it right...


----------



## WiR3D

Quote: 





kiteki said:


> I know these posts were over a week ago, I just wanted to note...
> 
> The 'common perception' is logical.  You can construct a DAC section and amplifier section on the same circuit board, or you can construct a DAC section and amp section on two seperate circuit boards, with two enclosures surrounding them, so what is the difference?  The difference is... if you get a nice rectangular piece of circuit board and connect them again... nothing.   This is also known as a cable, unless cables have some sort of issue.
> 
> ...


 
  I like your thinking, I support this question


----------



## qusp

what exactly IS the question?


----------



## kiteki

The op-amp choice behind the RCA in my DAC affects the sound of the amplifer it's connected to.
   
  The OPA2604 behind the line-out in my Teclast T51 has a '2604' sound to it.
   
  In both cases there is one variable too many, I'm just looking for - or looking for knowing what to look for - in a DAC or DAP that can avoid this variable.


----------



## qusp

only if you use a current out dac and drive your headphones directly from the IV convertor. only certain chips are suitable for this however, as only some chips are capable of dealing with the fast glitch energy of the current output; let alone at the same time as being loaded with headphones many completely unsuitable opamps are used for IV.
   
  the interaction between stages will be mitigated somewhat if you use a proper buffer after the IV like BUF634 or LME49600.
   
  in general though no, there will always be another variable, even if its just how well a certain chip will drive the cable. your best bet is just to make sure you keep either the amp, or the dac circuitry unchanged for the duration of each test of the other link in the chain.
   
  from what ive seen however you seem to struggle with this =)
   
  i'm not sure why though, you have multiple headphones you will try and will be trying multiple amps. find one you like, however the combination comes to be, who cares, just leave it and stop fiddling. an amp should perform on its own merits with multiple sources anyway.


----------



## iamdacow

hey guys maybe you can help me i have a 9v jds cmoy bb and i am looking to pair it with my jh16s, es5s and westone4s can anyone recommend a chip that is good for these earphones i want a clean and clear sound which i can easily pick out details with fantastic treble without sacrificing soundstage, mids lesser bass is ok as long as the opamp is very clear thanks


----------



## qusp

recommend something other than a cmoy for those headphones , youre right to put most of your money into headphones, but I think youve taken that a bit too far. no opamp 'upgrade' is going to turn a cmoy into a great amp


----------



## iamdacow

Quote: 





qusp said:


> recommend something other than a cmoy for those headphones , youre right to put most of your money into headphones, but I think youve taken that a bit too far. no opamp 'upgrade' is going to turn a cmoy into a great amp


 

 Yeah i do have a good amp for those cans however i got the cmoy just for fun so what could i get as an op amp?? Thanks


----------



## Jimlad

So I've decided to take the plunge into high-end audio and I've ordered myself some Sennheiser HD800s and a Matrix M-Stage amp. As a source, for now I think I should be able to get away with using my computer; I'm using an Auzentech Prelude card which has AKM-4396 DACs, which I'm told should be pretty good.
   
  My question is, since I'm aware that opamps can make a big difference to the sound, is it worth me spending a little bit extra and upgrading the opamps in either the Auzentech or the Matrix (or both)? The Auzentech uses a LM4562NA for front stereo channels (which is what I'll use as my source), while the Matrix uses a OPA2134. The alternative is that I go for an external DAC, but that would probably be an order of magnitude more expensive and I don't know if it'll be that much better.
   
  I was thinking maybe I should replace both the sound card and amp opamps with pairs of OPA827s or maybe ADA4637-1s, but honestly I'm open to all recommendations since I'm pretty new to this. I assume I'm going to have to use an adapter to connect them from dual chip to single socket - anyone know where I can get something like this in the UK? Also, for the opamps, is mouser the best place to go?


----------



## kiteki

qusp said:


> only if you use a current out dac and drive your headphones directly from the IV convertor. only certain chips are suitable for this however, as only some chips are capable of dealing with the fast glitch energy of the current output; let alone at the same time as being loaded with headphones many completely unsuitable opamps are used for IV.
> 
> the interaction between stages will be mitigated somewhat if you use a proper buffer after the IV like BUF634 or LME49600.
> 
> ...


 
   
  Thanks for the answer, that's the kind of specific answer I was looking for, plus it led me to further searching and info.  I have been driving headphones directly from the IV however the AK4396 is voltage-out it seems, I wonder what a good current-out DAC is?  When you say buffer after the IV, do you mean current-out DAC into passive IV, into the amplifier with a buffer chip into the op-amp?  Just curious, what happens if you used a chip not designed as a buffer as a buffer?  Like LT1115, or some video op-amp?
   
  I think if you made a blog in NwAv style centered around building a DAC, or an amplifer, it would be a refreshing read, since you seem to focus on scopes and specs a lot while being open minded to some other concepts as well, while he refuses to even_ measure_ AD797.
   
  Just my pov.
   
   


iamdacow said:


> Yeah i do have a good amp for those cans however i got the cmoy just for fun so what could i get as an op amp?? Thanks


 
   
  You will have to focus on op-amps which sound good supplied from a single 9V battery (+-4.5V).
   
  Or you can just buy a selection and try your luck.  AD797ANZ fits your description of sound at least.
   
   


jimlad said:


> So I've decided to take the plunge into high-end audio and I've ordered myself some Sennheiser HD800s and a Matrix M-Stage amp. As a source, for now I think I should be able to get away with using my computer; I'm using an Auzentech Prelude card which has AKM-4396 DACs, which I'm told should be pretty good.
> 
> My question is, since I'm aware that opamps can make a big difference to the sound, is it worth me spending a little bit extra and upgrading the opamps in either the Auzentech or the Matrix (or both)? The Auzentech uses a LM4562NA for front stereo channels (which is what I'll use as my source), while the Matrix uses a OPA2134. The alternative is that I go for an external DAC, but that would probably be an order of magnitude more expensive and I don't know if it'll be that much better.
> 
> I was thinking maybe I should replace both the sound card and amp opamps with pairs of OPA827s or maybe ADA4637-1s, but honestly I'm open to all recommendations since I'm pretty new to this. I assume I'm going to have to use an adapter to connect them from dual chip to single socket - anyone know where I can get something like this in the UK? Also, for the opamps, is mouser the best place to go?


 
   
  I use the AKM AK4396 too.
   
  My favorite sound with all op-amps I have considered, is OPA827 in the DAC, and OPA627 in my amplifer.
   
  Those are pretty expensive at mouser, so I'd go with an ebay seller with 99-100% feedback and you'll save a lot of money, at least that's what I've done.


----------



## PurpleAngel

Quote: 





jimlad said:


> So I've decided to take the plunge into high-end audio and I've ordered myself some Sennheiser HD800s and a Matrix M-Stage amp. As a source, for now I think I should be able to get away with using my computer; I'm using an Auzentech Prelude card which has AKM-4396 DACs, which I'm told should be pretty good.
> 
> My question is, since I'm aware that opamps can make a big difference to the sound, is it worth me spending a little bit extra and upgrading the opamps in either the Auzentech or the Matrix (or both)? The Auzentech uses a LM4562NA for front stereo channels (which is what I'll use as my source), while the Matrix uses a OPA2134. The alternative is that I go for an external DAC, but that would probably be an order of magnitude more expensive and I don't know if it'll be that much better.
> 
> I was thinking maybe I should replace both the sound card and amp opamps with pairs of OPA827s or maybe ADA4637-1s, but honestly I'm open to all recommendations since I'm pretty new to this. I assume I'm going to have to use an adapter to connect them from dual chip to single socket - anyone know where I can get something like this in the UK? Also, for the opamps, is mouser the best place to go?


 
  I would say to keep the Prelude for now. plug the Matrix M-stage straight into it.
  On eBay, there is a seller (frugalphile), who sells LME49990NA SOIC op-amps pre-soldered on to a dual SOIC to DIP-8 adapter, ships from Canada. They might be a good choice for the Prelude.


----------



## SpudHarris

Quote: 





jimlad said:


> So I've decided to take the plunge into high-end audio and I've ordered myself some Sennheiser HD800s and a Matrix M-Stage amp. As a source, for now I think I should be able to get away with using my computer; I'm using an Auzentech Prelude card which has AKM-4396 DACs, which I'm told should be pretty good.
> 
> My question is, since I'm aware that opamps can make a big difference to the sound, is it worth me spending a little bit extra and upgrading the opamps in either the Auzentech or the Matrix (or both)? The Auzentech uses a LM4562NA for front stereo channels (which is what I'll use as my source), while the Matrix uses a OPA2134. The alternative is that I go for an external DAC, but that would probably be an order of magnitude more expensive and I don't know if it'll be that much better.
> 
> I was thinking maybe I should replace both the sound card and amp opamps with pairs of OPA827s or maybe ADA4637-1s, but honestly I'm open to all recommendations since I'm pretty new to this. I assume I'm going to have to use an adapter to connect them from dual chip to single socket - anyone know where I can get something like this in the UK? Also, for the opamps, is mouser the best place to go?


 
   
  PurpleAngel mentioned LME49990 and I agree. I've bought about 6-8 off the same seller, he ships quickly and his soldering is faultless. In the UK I use Farnell for most purchases but have started using a smaller company lately who seem a bit cheaper - Timeline Components.


----------



## Jimlad

Thanks for the advice, guys. How do you find the LME49990 compares to the OPA827? Since it's not too pricey I think I might just buy two pairs and first replace the opamp in the Auzentech, then see how it goes and try replacing the Matrix opamp to see how much of a difference it makes. That said, should I expect to hear much of a difference with the LME49990 in the Matrix?


----------



## kiteki

jimlad said:


> Thanks for the advice, guys. How do you find the LME49990 compares to the OPA827? Since it's not too pricey I think I might just buy two pairs and first replace the opamp in the Auzentech, then see how it goes and try replacing the Matrix opamp to see how much of a difference it makes. That said, should I expect to hear much of a difference with the LME49990 in the Matrix?


 
   
  Haven't heard any LME's yet.
   
  The difference is pretty subtle, and yet significant at the same time.  I showed my portable amp to someone at a headphone store (him not having any idea what was inside of it), and he described the the sound of it exactly how the OPA627 is often described online.
   
  When I had a 'mystery box' of op-amps and listened to all of them, my two favorites happened to be the two most popular choices when I looked them up.
   
  It seems like Auzen is a fan of the OPA627 too - http://www.auzentech.com/site/products/opamp_intro.php
   
  In my opinion, if you use it you should put it in both the sound-card and the amp, or OPA827 in the sound-card, to get the 'right' sound, pairing OPA627 in the amp with a JRC in the DAC / sound-card doesn't sound 'right', at least in my limited experiments.
   
  Then there is always synergy - with the headphones, speakers or IEM's you're using, and the DAC chip.
   
  Music, and which studio it's recorded in, isn't very important at all, aside from trying different tracks from complicated electronic music, to a solo acoustic instrument or voice, and being very familiar with the sound of your standard / favorite equipment, which takes a while I think.
   
  If you focus on details, like whispers or faint tapping, I don't think you'll hear any difference, the difference is in the overall character, like 'digital' or 'analog' sounding.


----------



## kiteki

p.s. This thread may interest you, you'll most likely get more difference in sound from these op-amps than the standard ones out there - http://www.head-fi.org/t/412110/burson-discrete-opamp-v2-in-auzentech-x-fi-prelude
   
http://www.audio-gd.com/Pro/diy/OPA/OPAEN.htm
   
  For example you can try LME49990 verus dual OPA-SUN.


----------



## Mad Max

OPA827 rules.
   

   
  I think that it could still benefit from a little more bypassing.  =p
   
   
  LME49990 is great, too.


----------



## ecohifi

Sorry Mad Max,
   
  is that shot for a Transformer scene???
	

	
	
		
		

		
			




   
  Couldnt help myself.
   
  The OPA 827 is a great chip but it seams to loose resolution in complex passages.  This is where I finf the 49720 so interesting compared to the 49990.  In the circuit I have the 49990 are thin and lifeless but the resolution is great.  When yoiu go back to the 49720 you realise the 49990 trick you in believing its a better chip.


----------



## WiR3D

Quote: 





mad max said:


> OPA827 rules.
> 
> 
> 
> ...


 
  I'm surprised it doesn't have its own self powered power conditioner


----------



## Mad Max

Quote: 





ecohifi said:


> Sorry Mad Max,
> 
> is that shot for a Transformer scene???
> 
> ...


 
   
  That's the opposite of my observations.
   
  That many caps is overkill, just a ceramic and two 0.1uF MKP1837 are enough, lol.


----------



## zilch0md

ecohifi said:


> [snip]
> 
> The OPA 827 is a great chip but it seams to loose resolution in complex passages.  This is where I finf the 49720 so interesting compared to the 49990.  In the circuit I have the 49990 are thin and lifeless but the resolution is great.  When yoiu go back to the 49720 you realise the 49990 trick you in believing its a better chip.



 
 My 4x 49990 singles haven't even arrived yet and now I'm being enticed to order some 49270s, too! I'm going to have to stop reading this thread. (Not!)


----------



## SpudHarris

Quote: 





zilch0md said:


> My 4x 49990 singles haven't even arrived yet and now I'm being enticed to order some 49270s, too! I'm going to have to stop reading this thread. (Not!)


 
   
  The 49720 has an initial Wow/Hi-fi factor which made me want to listen more. However, fatigue soon sets in and it becomes boring and metalic. don't lose any sleep over the 49720 and enjoy the 49990 which has transients to die for....


----------



## zilch0md

Given that both you and qusp like the 49990, I'm sure I'll be happy with it. I can't afford to do any wild experiments. I'm content to follow in the footsteps of your experience.  Mike


----------



## Mad Max

Quote: 





spudharris said:


> The 49720 has an initial Wow/Hi-fi factor which made me want to listen more. However, fatigue soon sets in and it becomes boring and metalic. don't lose any sleep over the 49720 and enjoy the 49990 which has transients to die for....


 
   
  You have to add at least a 0.1uF ceramic across the power pins to get rid of the "rolled-up" treble that it often has when dumped randomly into any piece of equipment.  Its balance becomes very linear like my other opamp modules with psu bypass caps, yet it still retains a strangely, and unpleasantly, artificial sound.  More tolerable, at least.


----------



## Tommy Thong

Hi Nigel,
  how's the sound with ADA4637-1 & ADA4627-1?compare with LME49990?


----------



## SpudHarris

Well, the ADA4637 was a long time favourite of mine. I never really got the 4627 like some (MadMax), not that I didn't try, I used it over a period of time but just never fell in love with it. We are all different with different needs and preferences and that's why you should always take what others say with  this in mind. The LME49990 is not just a favourite of mine but many others so I guess majority rules in this instance. I believe it to be a better OpAmp than the 4637 because it is a more realistic sound. The 4637 sure is a lot of fun but again, it all depends on what floats your boat and that's why it's nice to be able to roll coz some nights I just want a musical unfatiguing evening and other nights I want emotion and realism.
   
  I recently tried the THS4031 (single) and 4032 (dual) and have to say in my PB-2 and Fi-Quest they are very, very nice indeed. All this said, I have reflected on the time spent obsessing over the Holy Grail of OpAmps and realised that although fun at times it is no replacement for a properly implemented or optimised OpAmp and circuit.
   
  Haha, bet you wish you never asked now 
	

	
	
		
		

		
		
	


	




......


----------



## genclaymore

Look like they much be very good if alot of people like the LME49990s. Only reason i don't have them, as I can't solder to put them on adapters.


----------



## zilch0md

Hi genclaymore!
   
  Quote: 





genclaymore said:


> Look like they much be very good if alot of people like the LME49990s. Only reason i don't have them, as I can't solder to put them on adapters.


 
   
  I can't solder very well, either, but I ordered two pair of LME49990 singles, already soldered onto SOIC-to-DIP8 adapters, from an ebay seller named *frugalphile*.
   
  Try this link:  http://www.ebay.com/itm/2x-LME49990-DIP8-ADAPTERS-/190679106821?pt=US_Amplifier_Parts_Components&hash=item2c655c4505#ht_968wt_1140
   
  If that link doesn't work, try searching eBay for this item:   2x LME49990 DIP8 ADAPTERS
   
  I haven't received them yet (ordered a couple of days ago), but he currently has 100% positive feedback from 501 transactions.
   
  I read very positive things about his soldering skills here at Head-Fi.  Try searching Head-Fi for his ebay name: * frugalphile*
   
  I wish his store offered more ready-to-use op-amps and buffers on DIP8 adapters, but I'm happy for now that he offers the LME49990.
   
  [size=medium]*Mike*[/size]


----------



## kiteki

genclaymore said:


> Look like they much be very good if alot of people like the LME49990s. Only reason i don't have them, as I can't solder to put them on adapters.


 
   
http://www.ebay.com/itm/1PCS-Dual-Mono-LME49990MA-replace-OPA2604-NE5532-TL072-/320863640326 (seller: hifiic)
   
  Edit:  Noticed Mike posted another seller above.


----------



## zilch0md

Hi kiteki,
   
  Quote: 





kiteki said:


> http://www.ebay.com/itm/1PCS-Dual-Mono-LME49990MA-replace-OPA2604-NE5532-TL072-/320863640326 (seller: hifiic)
> 
> Edit:  Noticed Mike posted another seller above.


 
   
   
  That's a much better price for the pair of LME49990 "duals" than what I paid for the two pair of LMD49990 singles - ignoring that hifiic is in China vs. fruglphile being in Canada.  Either way, I suspect the shipping will take a while to reach the U.S. where glenclaymore and I both reside.
   
  Do you suppose there is any SQ advantage to be had by running four singles in an iBasso PB2 vs. two of hifiic's "Dual to Mono" contraptions - since the "Dual to Mono" aren't really Duals but rather twinned Singles?
   
  Mike


----------



## kiteki

Like this?
   



   
  I'm not familiar with every last corner of the design but intuitively twin single mono (in my ebay link) at the top, versus 4 single mono in a row, should yield the exact same result.
   
  In something like OPA111 versus OPA2111, two x of the former seems better, but I'm not sure if that's the case, if you seperate the stereo channels, what if there's a 1 nanosecond delay?  Just an example.


----------



## ecohifi

Quote: 





zilch0md said:


> My 4x 49990 singles haven't even arrived yet and now I'm being enticed to order some 49270s, too! I'm going to have to stop reading this thread. (Not!)


 
  I havent tried the LME 49880 and 49860 but are willing to give them a go!!!!!!
	

	
	
		
		

		
		
	


	




   THe LME 49860 are higher supply voltage version of the LME 49720 and from what I have seen its also better!


----------



## ecohifi

Quote: 





jimlad said:


> Thanks for the advice, guys. How do you find the LME49990 compares to the OPA827? Since it's not too pricey I think I might just buy two pairs and first replace the opamp in the Auzentech, then see how it goes and try replacing the Matrix opamp to see how much of a difference it makes. That said, should I expect to hear much of a difference with the LME49990 in the Matrix?


 
  Both are very different chips and I can live with both


----------



## ecohifi

Quote: 





tommy thong said:


> Hi Nigel,
> how's the sound with ADA4637-1 & ADA4627-1?compare with LME49990?


 
  I can live with the ADA4627-1brz not the arz, the arz are a little unstable for my liking.  The ADA4627-1 brz I had in a dac and a pre and I lived with it for about 9mths, a chip that as far as Im concern is hard to beat.  Very expensive
	

	
	
		
		

		
			





  I prefer them over the OPA 627 at the price point.   The LME are value compared to them!
   
  Im going to try the LME 49860 AND THE 49880 hopefully soon


----------



## zilch0md

Quote: 





kiteki said:


> Like this?
> 
> 
> 
> ...


 
   
  I like your thinking - makes sense to me.  Ron (HiFlight) had convinced me that duals don't suffer any loss of SQ relative to singles, but for op-amps where dual versions don't exist (or are unavailable), the "Dual to Mono" idea seems appealing.
   
  Thanks,
   
  Mike


----------



## kiteki

Interesting so the Lite DAC-AH is "improved" by removing the op-amps in place for capacitors, changing it to passive I/V - http://www.coemaudio.com.au/Sources/DACs/183/
   
  This guy says that sounds really "weak" though - http://lampizator.eu/LAMPIZATOR/REFERENCES/AH%20DAC/AHDAC.html
   
  Still looking for DAC's for op-amp evaluation...


----------



## WiR3D

Quote: 





kiteki said:


> Interesting so the Lite DAC-AH is "improved" by removing the op-amps in place for capacitors, changing it to passive I/V - http://www.coemaudio.com.au/Sources/DACs/183/
> 
> This guy says that sounds really "weak" though - http://lampizator.eu/LAMPIZATOR/REFERENCES/AH%20DAC/AHDAC.html
> 
> Still looking for DAC's for op-amp evaluation...


 
  I would love it if you found one, would make it fun to play with opamps, because you could have the dac its in own compensated circuit, and just swap out opamp circuits (opamps + their own compensation on a separate circuit.)
   
  But different chips are made for different things, like the AD797 (Sigma-delta buffer) so you won't really be able to use them all anyway, but the concept is still fun.


----------



## kiteki

Well my AK4396 DAC has exactly 1 op-amp socket and I can listen directly from the line-out, which is what I've done, it's when I connect my amplifier I start worrying about the op-amp in my DAC a little, so a current-out DAC chip into passive I/V into the buffer in my amplifier into [insert op-amp] seems like a more ideal scenario.
   
  It seems like there is no consensus on passive I/V or using an op-amp at least - http://www.head-fi.org/t/512389/mini-dac-tda1543-x-4-nos/135#post_7233717


----------



## qusp

Quote: 





> what if there's a 1 nanosecond delay?


 
  nothing happens; there are roughly 50 nano seconds in each sample at 20khz, which is already above many peoples hearing threshold
   
  passive IV with transformers on the above dac is very nonlinear, most people like the 2nd harmonic distortion. passive IV with resistors only works really well if the dac chip has decent output compliance. EVERY design you can come up with presents a compromise of some sort, just pick one and keep it static, while experimenting with the rest. this quest to find something that doesnt have any effect on following stages ie completely colourless is not realistic, particularly as a rather basic level hobbiest, no offense intended.
   
  there are no truly modern current out dacs that have high enough current output to drive a resistor by itself and give best performance. the pcm1704 is about as close as you'll get, but a truly reference 1704 build is a pretty big task and not cheap. most passive IV circuits are famous for being 'musical' 'natural' 'unfatiguing' which are all in themselves different colourations


----------



## qusp

ADxxxxARZ unstable vs BRZ? haha you can back this up? I recommend you drop the guys at AD an email, I think they would be very interested in your findings


----------



## kiteki

qusp said:


> > what if there's a 1 nanosecond delay?
> 
> 
> 
> nothing happens; there are roughly 50 nano seconds in each sample at 20khz, which is already above many peoples hearing threshold


 
   
  I didn't mean exactly 1 nanosecond...
   
  Anyway I don't believe in thresholds since they change all the time and usually come from small university studies, with a select number of people, there's plenty of incorrect thresholds on Wikipedia.  Afterall, hasn't the SanDisk Clip+ surpassed *all *of them in audio?  At least according to the multi-thousand dollar dScope reviews of it, so by that logic nothing in your AckoDac is audible either. ^^


----------



## Mad Max

Quote: 





qusp said:


> ADxxxxARZ unstable vs BRZ? haha you can back this up? I recommend you drop the guys at AD an email, I think they would be very interested in your findings


 
   
  Maybe he meant to say "colored". It certainly sounds more colored without extra bypass caps vs. BRZ, but both grades are hard for us to stabilize. We've got overheating 797s _and_ overheating 4627s, lol.


----------



## zilch0md

I recently read in the 6moons review of the Meier Concerto that Jan Meier described the AD797s (which were used in both his Concerto and the current Classic model) as being particularly sensitive to power supply quality:  
   
Quoting Jan Meier: 





> More than any other opamp I've used before, *the AD797 is very sensitive to power supply quality*, hence I run 85.000uF of capacity via Nichicon audio-grade capacitors as well as extensive regulation and filtering. I always use linear power supplies to prevent high-frequency noise pollution.


 
   
  This gave me revisit my use of AD797s in the buffer stage of my PB2 (where I had previously reported extreme overheating during an evening's use, but have not been able to reproduce the overheating since then).  
   
  I had a vague recollection that I may have been using my Energizer XP8000 external lithium-ion battery pack to power the PB2 at 16VDC, *while the XP8000 was being recharged* - which normally isn't the case.
   
  Sure enough, the AD797s started overheating when the PB2 was powered by an XP8000 battery pack that was itself being recharged via its switching (non-linear) AC adapter.  
   
  When I unplugged the XP8000 from its charger, the AD797s went back to normal operating temperatures (they stopped oscillating).
   
  Mystery solved.  The XP8000's charger can cause the AD797s to oscillate.  
   
  Mike


----------



## ecohifi

ADA 4627-1 brz is a higher grade of the arz, I have found that most ADI chips require quality PSU and strick correct bypassing to work.  The ARZ in the same circuit has higher audiable bottom end distortion. You will not notice it if you used the arz version first, it isn't until you used the brz for a few days and then place the arz in place without alter anything.
  For some unknown reason the ADI chips run hot accept for the ADA4610-2.  But the ADA 4610-2 is low resolution.
   
  I now have a CRO to show that the ADA 4627-1 has low level oscillation even with documented bypassing, this is possibly due to landscape that I am using and not the recommended bypassing.  I even think that using thru-the-hole components are useless to fully eliminate oscillation and noise and SMD is the next step.
   
  I now returned to LME devices like the LME 49720 as this chip is stable and  suited to the circuit I am using.


----------



## kiteki

qusp said:


> passive IV with transformers on the above dac is very nonlinear, most people like the 2nd harmonic distortion. passive IV with resistors only works really well if the dac chip has decent output compliance. EVERY design you can come up with presents a compromise of some sort, just pick one and keep it static, while experimenting with the rest. this quest to find something that doesnt have any effect on following stages ie completely colourless is not realistic, particularly as a rather basic level hobbiest, no offense intended.
> 
> there are no truly modern current out dacs that have high enough current output to drive a resistor by itself and give best performance. the pcm1704 is about as close as you'll get, but a truly reference 1704 build is a pretty big task and not cheap. most passive IV circuits are famous for being 'musical' 'natural' 'unfatiguing' which are all in themselves different colourations


 
   
  To be blunt...
   
  "Not another nosser", "passive I/V sux", "just keep whatever DAC static" and "try harder next time".  Let's say you are hypothetically correct about current-out and passive I/V, I still need to _hear_ the concept first like any real scientist.  I'm asking for advice on finished DAC's, sooo... the skill level is only on the designer, unless you mean my level of consumer savvy.


----------



## FritzS

Quote: 





zilch0md said:


> I recently read in the 6moons review of the Meier Concerto that Jan Meier described the AD797s (which were used in both his Concerto and the current Classic model) as being particularly sensitive to power supply quality:
> 
> 
> This gave me revisit my use of AD797s in the buffer stage of my PB2 (where I had previously reported extreme overheating during an evening's use, but have not been able to reproduce the overheating since then).
> ...


 
   
  Are using JLH ripple eaters between lithium-ion battery pack and amp are a way for you to solve this problem?
  Or a lowpass filter with choke coils and caps?
   
   
  http://www.diyaudio.com/forums/group-buys/167286-john-linsley-hood-ripple-eater-3.html

 http://rockgrotto.proboards.com/index.cgi?board=m&action=display&thread=5645

 http://www.gt6.co.uk/JLHPSRR/John%20Linsley%20Hood%20ripple%20Eater%20-%20Rock%20Grotto%20Charity%20Edition.html

 http://www.audiofuture.net/showthread.php?95-JLH-Ripple-Eaters


----------



## Mad Max

To stabilize LME49990 in my DAC, should I add the RLC compensation thing that the datashet prescribes? Also, it is driving a MOSFET buffer, so does that have high enough impedance at the buffer's inputs? But wouldn't adding that compensation color the sound due to the inductor and cap? Or does the inductor and/or resistor alleviate that?


----------



## ecohifi

All components that is added will affect SQ in my experience.  I would be providing documented compensation as this is a start. 
   
  FWIW with capacitor bypassing and compensation, latest findings in a Silicon Chip article of there latest M3 100W power amp with On-semi output devices have "discovered" that removing all ceramic capacitors that where used for compensation and stability, reduces distortion in the audio frequency path.  This is contarary to there statement made on the use of MKPs and in this article they have opted to use MKPs throughout the design.  Very differernt direction compared to there previous offerings and discussions. 
  In the NAD M51, they are using polystyrene capacitors throughout for compensation on there LME 49990 balance output stage.


----------



## zilch0md

Hi FritzS!
   
  Quote: 





fritzs said:


> Are using JLH ripple eaters between lithium-ion battery pack and amp are a way for you to solve this problem?
> Or a lowpass filter with choke coils and caps?
> 
> 
> ...


 
   
  Thanks for the links - interesting reading!
   
  The AD797 oscillation problem (in the buffer stage of my PB2) was solved when I unplugged the XP8000 battery pack from its charger, so I don't really need a solution, now, but I do appreciate the links.
   
  Thank you!
   
  Mike


----------



## Jimlad

Well, got my HD800s and Matrix M-Stage and they sound fantastic! I also got my LME49990s through the post and tried them out... they're definitely better in the Auzentech sound card, the sound became clearer and more detailed, but I found when I put the second pair in the M-Stage, it was clearer still but I was getting quite a lot of background noise. I wasn't a fan of that so I've put the stock opamp back in and I'm happy. I was surprised at the background static though, has anyone else experienced this?


----------



## Mad Max

Perhaps you did not insert it correctly.
  I got no additional noise with LME49990 and my M-Stage.


----------



## electronicmaji

Wrong thread. Derp.


----------



## Jimlad

Quote: 





mad max said:


> Perhaps you did not insert it correctly.
> I got no additional noise with LME49990 and my M-Stage.


 
   
  I just tried re-inserting them and I get the exact same sound and background hiss as before. It's not crazy-loud but it's quite noticeable. Could a faulty chip do this?
   
  There's actually a little bit of hiss with the LM45625na, just not as much. This is present even when I have nothing plugged into the amp's inputs. Is that normal?


----------



## kiteki

I found a decent current-out / passive IV NOS DAC to experiment with, any thoughts on anything special to look out for when rolling op-amps in an amp connected to a NOS DAC?


----------



## zilch0md

Quote: 





zilch0md said:


> Given that both you and qusp like the 49990, I'm sure I'll be happy with it. I can't afford to do any wild experiments. I'm content to follow in the footsteps of your experience.  Mike


 
   
  The 4x LME49990s arrived today.   
	

	
	
		
		

		
			




   
  I popped them into my PB2 and I've been listening for about an hour. I'm using them with the HA5002 buffers and my first thoughts were that they sound brighter than even the OPA1612s but they're smoother in the highs, and not at the expense of detail. The OPA1612s can be just a tiny bit edgy or harsh with my Sony PCM-M12 line out as source - which is known for being bright.  
   
  So I like these LME49990s more than the OPA1612s because the smoothness comes without throwing a veil over everything.  Tons of detail without an edge.  Beautiful!
   
  Surely, I'm imagining all of this.  
	

	
	
		
		

		
		
	


	



   
  Mike


----------



## kiteki

Ah, so the OPA1612 has more detail / edge than the LME49990?


----------



## Mad Max

Quote: 





jimlad said:


> I just tried re-inserting them and I get the exact same sound and background hiss as before. It's not crazy-loud but it's quite noticeable. Could a faulty chip do this?
> 
> There's actually a little bit of hiss with the LM45625na, just not as much. This is present even when I have nothing plugged into the amp's inputs. Is that normal?


 
   
  Perhaps the issue is something else.  Have you tried going through the M-Stage thread?  A number of issues have been covered there.
   
  This thing is your friend:  
   
  Alternatively, you can try using google, just make sure to add "site:head-fi.org" (without quotations) at the end.
   
   
   
  Quote: 





kiteki said:


> Ah, so the OPA1612 has more detail / edge than the LME49990?


 
   
  It depends.


----------



## SpudHarris

Quote: 





jimlad said:


> Well, got my HD800s and Matrix M-Stage and they sound fantastic! I also got my LME49990s through the post and tried them out... they're definitely better in the Auzentech sound card, the sound became clearer and more detailed, but I found when I put the second pair in the M-Stage, it was clearer still but I was getting quite a lot of background noise. I wasn't a fan of that so I've put the stock opamp back in and I'm happy. I was surprised at the background static though, has anyone else experienced this?


 
   
  I have this on a couple of my amps. Fortunately the amp best suited is my Fi-Quest which has bandwidth limiting switches. Not sure if that helps but at least you know it's not just you.


----------



## kiteki

I'm happy people actually talk about real differences in sound in this thread unlike most others on h-f.  I just started an anticipation / review thread for a Vsonic IEM and then people start spamming the Fiio E6 is the only amplifier ever necessary and it's better than a lot of sound-cards due to low 
	

	
	
		
		

		
		
	


	




... =/


----------



## Mad Max

Those tiny Fiios are jokes.


----------



## zilch0md

Quote: 





kiteki said:


> Ah, so the OPA1612 has more detail / edge than the LME49990?


 
   
  I'm pretty sure I didn't say that.  I think they're neck-and-neck for detail - it's hard to say, from my perspective - but the LME499990 is smoother - not quite as edgy with my already bright source, the Sony PCM-M10.
   
  In my limited experience, "smoothness" comes at the expense of detail, but that's not the case with the LME499990. I'm thinking the OPA1612 has the same detail, but they're just not as smooth in the highs.
   
  The bass seems to be tighter, too, with the LME49990, but it's not dark, warm, or colored in any way - the LME49990 is neutral - very neutral - it's doing what an audio amp is supposed to do - increasing the gain without adding or subtracting to the traits already in the signal.  It's extremely transparent.  
   
  These LME49990s are going to spend a lot of time in my PB2!
   
  Mike


----------



## SpudHarris

Quote: 





zilch0md said:


> I'm pretty sure I didn't say that.  I think they're neck-and-neck for detail - it's hard to say, from my perspective - but the LME499990 is smoother - not quite as edgy with my already bright source, the Sony PCM-M10.
> 
> In my limited experience, "smoothness" comes at the expense of detail, but that's not the case with the LME499990. I'm thinking the OPA1612 has the same detail, but they're just not as smooth in the highs.
> 
> ...


 
   
  Sounds the same as my experience. I likened the 49990 to a high end tube amp because of the great resolution and detail. Anyone that has experienced a decent tube amp will understand that there is a fullness to the sound, micro details without glare, just magical....


----------



## zilch0md

Quote: 





spudharris said:


> Sounds the same as my experience. I likened the 49990 to a high end tube amp because of the great resolution and detail. Anyone that has experienced a decent tube amp will understand that there is a fullness to the sound, micro details without glare, just magical....


 
   
  Yes!   I've put a few more hours on them, now, and I remain very impressed.  
   
  I have to add that the soldering skills of the ebay seller named "frugalphile" are impeccable.  The packaging was excellent, too.  It's curious that his ebay store offers very little other than the LME49990 SOICs soldered to DIP8 adapters.  They must be popular op-amps.  
	

	
	
		
		

		
			




   
   
*Frugalphile's LME49990 singles*
   

   
  http://www.ebay.com/itm/2x-LME49990-DIP8-ADAPTERS-/190679106821?pt=US_Amplifier_Parts_Components&hash=item2c655c4505
   
   
*Frugalphile's LME49990 Dual (the other package is underneath the PCB)*
   

   
  http://www.ebay.com/itm/DUAL-SOIC-LME49990-DIP8-ADAPTER-/190682726763?pt=US_Amplifier_Parts_Components&hash=item2c6593816b
   
  Mike


----------



## kiteki

This might seem off-topic in this thread, but I wanted to share this with you keen listeners, the JVC FXD80 IEM, most precise imaging I've ever heard I think.


----------



## SpudHarris

Frugalphile does sell other chips on occasion.
   
  I snapped a few of these a couple of months back, they are very, very clean sounding. Cooler side of neutral but not metalic.


----------



## zilch0md

Those sound like they'd be a good match for a warm source, like the RWA iMod.  
   
  I borrowed one of those for a couple of weeks and found it to be too warm for my tastes when used with the very neutral Meier Stepdance.


----------



## zilch0md

*Check out these tutorial pages published by National Semiconductor, regarding op-amps! *
   
  Beginning of the course:  http://www.national.com/AU/design/courses/268/main.htm
   
  The Basics of an Operational Amplifier:  http://www.national.com/AU/design/courses/268/the02/00the02.htm
   
  Operation Amplifier Parameters:  http://www.national.com/AU/design/courses/268/par03/00par03.htm
   
  The pages seen at this last link, alone, will greatly enhance your ability to understand op-amp datasheets.
   
  Joy!
   
  Mike


----------



## Tommy Thong

hi Nigel,
i ordered some of those LME49880, still wait on the mail, i'm hoping they will come asap


----------



## SpudHarris

My name is Nigel (spud) and I'm.........a...........recovering addict.
   
  I know this is blasphemy here but I'm trying not to roll at present. I have picked up a couple of RSA amps (Tomahawk + SR71B) and am enjoying them very much (especially the Tomahawk). I am going on vacation soon and want to cut down on the amount of gear I take in my hand luggage. Going out to Cyprus last year they made me unpack and show what everything did, I had 2 portable amps + case of about 50 various opamps + ipod + Clas + iMod + cables and interconnects + ES5's + K702's + chargers/USB's + laptop. All neatly packed to begin with then thrown back into backpack in haste because we were late boarding. This time I have my iMod and Tomahawk (Strapped) + SR71B + ES5's and less stress.
   
  I may well sell off the PB2/Fi-Quest/P4 and quit rolling for good.........


----------



## WiR3D

Quote: 





spudharris said:


> My name is Nigel (spud) and I'm.........a...........recovering addict.
> 
> I know this is blasphemy here but I'm trying not to roll at present. I have picked up a couple of RSA amps (Tomahawk + SR71B) and am enjoying them very much (especially the Tomahawk). I am going on vacation soon and want to cut down on the amount of gear I take in my hand luggage. Going out to Cyprus last year they made me unpack and show what everything did, I had 2 portable amps + case of about 50 various opamps + ipod + Clas + iMod + cables and interconnects + ES5's + K702's + chargers/USB's + laptop. All neatly packed to begin with then thrown back into backpack in haste because we were late boarding. This time I have my iMod and Tomahawk (Strapped) + SR71B + ES5's and less stress.
> 
> I may well sell off the PB2/Fi-Quest/P4 and quit rolling for good.........


 
  Or get a VAMP and cut it down even more. But they may think its a modified cellphone, and that its an explosive, or controls an explosive.


----------



## zilch0md

Quote: 





spudharris said:


> My name is Nigel (spud) and I'm.........a...........recovering addict.
> 
> [snip\
> 
> I may well sell off the PB2/Fi-Quest/P4 and quit rolling for good.........


 
   
  I hear you Nigel!  I managed to go about 16 days without rolling, prior to ordering and receiving the LME49990s, recently - and they are so nice (with HA5002s in the PB2), I'm thinking I can ignore my other op-amps forever (maybe)!   
	

	
	
		
		

		
		
	


	




  But seriously, they sound so much better than my next favorite combination, across multiple genres of music, I'm feeling content to stop experimenting.  
   
  Unlike you, my obsession is not facilitated by an ability to solder SOIC packages to DIP 8 adapters!   
   
*Now, please point me to a link where you've compared the Tomahawk and SR-71B to the PB2! *  Or send me a quick PM!  
   
  Finding people who have direct experience with both the the SR-71B and the PB2 is next to impossible.  I've heard that Ray Samuels covers his op-amps with paint to protect his designs, and I can respect that, but I'm curious what you're hearing - I'm thinking he must be using something other than neutral-sounding op-amps like AD797s (Meir Concerto and Classic) or OPA1611s (Meier Stepdance) - going by reviews which say that the SR-71B has the RSA "house sound" - warm, not neutral.
   




   
  Thanks,
   
  Mike


----------



## SecrtAgentMan

So do all of the OP-Amps need to be soldered to a DIP adapter?


----------



## SpudHarris

Quote: 





zilch0md said:


> I hear you Nigel!  I managed to go about 16 days without rolling, prior to ordering and receiving the LME49990s, recently - and they are so nice (with HA5002s in the PB2), I'm thinking I can ignore my other op-amps forever (maybe)!
> 
> 
> 
> ...


 
   
  Hiya Mike,
   
  not really written notes on the difference/similarities of the PB2 and SR71B. I should really do this.
   
  The Tomahawk is the most surprising amp I've ever owned, worth so much more than they sell for on the used market. I have used it with full sized cans and it's good and despite it's size it will still power the LCD-2's, however, it really brings IEM's to life. It's hard to explain really, but it has resolution and depth with IEM's that I have never heard before. I bought it because someone came to pick up my D7000's from my house and I let him audition them with my amps, in return he let me try his Tomahawk and although I didn't say much at the time, I knew after 2-3 minutes that it was something special.
   
  I'll pm you with details of the SR71B because that is a different beast altogether and fed balanced from my M-Dac is as good as any high end amp I've heard. It even powers the HE-6 with authority.
   
  Give me a few days to make some notes.
   
  All the best - Nigel


----------



## zilch0md

Thanks Nigel!   No hurry!


----------



## zilch0md

Quote: 





secrtagentman said:


> So do all of the OP-Amps need to be soldered to a DIP adapter?


 
   
  No, there are a few out there that are manufactured in the ready-to-use DIP 8 form factor, but most modern op-amps are SOIC format.  Somebody please step in if I've said something incorrect, here.
   
  Mike


----------



## SecrtAgentMan

Great to hear ^^
   
  So I've been reading through the thread and I still can't come to a conclusion as what to get.
   
  I listen to some bass heavy music, and I'd like for soundstage and sound positioning to be present as well if possible since I do game with these headphones.
   
  Currently I use the ATH-M50s. If anybody could give me a recommendation that would be great.
   
  Thanks.


----------



## genclaymore

Quote: 





zilch0md said:


> No, there are a few out there that are manufactured in the ready-to-use DIP 8 form factor, but most modern op-amps are SOIC format.  Somebody please step in if I've said something incorrect, here.
> 
> Mike


 

 Don't forget about the ones that are TO-99 which are metal caps. That needs to be put on To-99 to dip-8 adapters to be used. Tho some Bent them and place them directly inside the dip-8 sockets. Which I wouldnt do.


----------



## Mad Max

Because of possible poor contact?


----------



## zilch0md

Quote: 





secrtagentman said:


> Great to hear ^^
> 
> So I've been reading through the thread and I still can't come to a conclusion as what to get.
> 
> ...


 
   
  Unfortunately, unless someone is using the same source, same amp, and same headphones, not to mention having different ears and different tastes, it's really hard to make recommendations with any guarantee.  In my limited experience with rolling op-amps (compared to several other contributors, here), I'd say your best bet is to start rolling and see what sounds good to you.  It can get expensive, but you can start with the stuff that everyone else is raving about.  In my case, that would be the aforementioned HA5002 for buffers and the LME49990 for input voltage gain.  But that's just the "flavor of the week."  Hopefully, it will be the flavor of the month, or longer...
   
  Which amp are you using?
   
  Mike


----------



## SecrtAgentMan

Quote: 





zilch0md said:


> Unfortunately, unless someone is using the same source, same amp, and same headphones, not to mention having different ears and different tastes, it's really hard to make recommendations with any guarantee.  In my limited experience with rolling op-amps (compared to several other contributors, here), I'd say your best bet is to start rolling and see what sounds good to you.  It can get expensive, but you can start with the stuff that everyone else is raving about.  In my case, that would be the aforementioned HA5002 for buffers and the LME49990 for input voltage gain.  But that's just the "flavor of the week."  Hopefully, it will be the flavor of the month, or longer...
> 
> Which amp are you using?
> 
> Mike


 
  Well I'm using a sound card so no amp (unless the sound card is considered one). It's the Asus Essence STX.
   
  So 2x LME49990 for I/V and then just 1x HA5002 for buffer? Where can I buy the buffer? I saw the LME's on Ebay.


----------



## zilch0md

Quote: 





secrtagentman said:


> Well I'm using a sound card so no amp (unless the sound card is considered one). It's the Asus Essence STX.
> 
> So 2x LME49990 for I/V and then just 1x HA5002 for buffer? Where can I buy the buffer? I saw the LME's on Ebay.


 
   
  For the HA5002 buffer, already soldered to a DIP8 adapter, try sending a PM to Head-Fi member *HiFlight*.  Ask Ron if he would be willing to do it for you and how much it would cost, including shipping.
   
  Ron solders the HA5002s routinely for his various TopKits (collections of popular op-amps he puts together for owners of iBasso headphone amps).
   
  Warning:  The LME49990 is a JFET op-amp that requires a minimum operating supply voltage of +- 5V.  Most portable headphone amps can satisfy this requirement, but your sound card might not.   ???
   
*UPDATE (two months later):*  The 49880 is a JFET, but the 49990 is not (at least I can't find any reference saying that the 49990 is a JFET...)
   
  Here is the datasheet for the LME49990:   http://www.ti.com/lit/ds/symlink/lme49990.pdf
   
  Here is the datasheet for the HA5002:  http://www.intersil.com/content/dam/Intersil/documents/fn29/fn2921.pdf
   
  Even if the sound card can satisfy the LME49990's power requirements, there's something else to consider:  The LME49990's THD and Noise specifications improve as the supply voltage increases.  In other words, you will get the best possible performance out of an LME49990 when the supply voltage is at +- 15V (just below its absolute maximum of +- 18V).   
   
  If you are unable to determine the operating supply voltage delivered by your sound card, you might be better off selecting an op-amp that's designed for lower operating voltages. 
   
  The OPA1611 would be a better choice if you don't know what your sound card's supply voltage is, as the bi-polar OPA1611 can use an operating supply voltage as low as +- 2.25V up to +- 18V.  It's a very popular op-amp, too - known for being extremely transparent and neutral.  (It's the op-amp used in the Meier Audio Stepdance portable amplifier, for example.)  But even the OPA1611 sounds best when supplied with 15 Volts.
   
  Here is the datasheet for the OPA1611:  http://www.ti.com/lit/ds/symlink/opa1611.pdf
   
  Ron (HiFlight) would also be able to quote a price on the OPA1611s, already soldered to DIP8 adapters.
   
  With the understanding that you are proceeding *at your own risk*, you can always just order them, roll them in, and see what happens.   
	

	
	
		
		

		
			




   
  Mike


----------



## SpudHarris

Quote: 





zilch0md said:


> For the HA5002 buffer, already soldered to a DIP8 adapter, try sending a PM to Head-Fi member *HiFlight*.  Ask Ron if he would be willing to do it for you and how much it would cost, including shipping.
> 
> Ron solders the HA5002s routinely for his various TopKits (collections of popular op-amps he puts together for owners of iBasso headphone amps).
> 
> ...


 
   
  Mike,
   
  you my friend have come a long way in a short time 
	

	
	
		
		

		
		
	


	



   
  I know we joke about the addiction sometimes but you really have started to understand the science behind OpAmps. More power to you. I'm still learning slowly, I recon I have more experience in terms of physical try outs but by probably less understanding than you haha. You sound like a pro mate!
   
  We are agreed on the 49990 though. I wish someone would make a decent powered portable optimised for that chip. I'm not aware of one but maybe anyone in the know could chime in if there is such a thing....
   
  Ta! - Nigel


----------



## DingoSmuggler

The analogue stage for the STX is +/-12V, so looks like no go on the 49990.


----------



## Mad Max

Which is within 49990's range (+/-5V to +/-18V) as far as voltage.


----------



## SecrtAgentMan

Thanks guys, also I've been looking on Ebay for the LME49990 soldered to a DIP8 adapter.
   
  I've noticed there are two of them, one that comes in a pair, and one that is just as single one with 2 LME49990's soldered to both sides of the adapter.
   
  Is one better than the other? I've been looking at frugalphile's listing.


----------



## Mad Max

49990 is a single, or mono, opamp, so you need two on one adapter to replace a dual opamp like OPA2134 or OPA2604.


----------



## PurpleAngel

Quote: 





secrtagentman said:


> Thanks guys, also I've been looking on Ebay for the LME49990 soldered to a DIP8 adapter.
> 
> I've noticed there are two of them, one that comes in a pair, and one that is just as single one with 2 LME49990's soldered to both sides of the adapter.
> 
> Is one better than the other? I've been looking at frugalphile's listing.


 
  Chances are the DIP-8 slot your plugging op-amps into is dual channel and the LME49990 (SOIC) is single channel op-amp.
  So two LME49990 SOIC op-amps need to be soldered on to a dual SOIC to DIP-8 adapter.


----------



## SecrtAgentMan

I use the Essence STX if that is any help ^^


----------



## PurpleAngel

Quote: 





secrtagentman said:


> I use the Essence STX if that is any help ^^


 
  The Essence STX (& ST) comes with three dual channel DIP-8 sockets.
  I'm using 3 AD797BRs in mine
  The LME49990 seems to be well liked.


----------



## zilch0md

Thanks for the kind words, Nigel!   I'm always hoping somebody will swoop down and correct anything I write that's incorrect.  That's the beauty of forums like this - everything must pass peer review.  
   
  There's so much collaboration going on here, at the moment - I dig this team work!
   
  So, SecrtAgentMan...  It sounds like you can use these LME49990 *duals*, for example:
   
http://www.ebay.com/itm/DUAL-SOIC-LME49990-DIP8-ADAPTER-/190682726763?pt=US_Amplifier_Parts_Components&hash=item2c6593816b
   
  Ebay seller Frugalphile's soldering is very neat and clean - I bought four singles from him for my PB2 amp. 
   
  Go for it!  
   




   
  Mike


----------



## DingoSmuggler

Quote: 





mad max said:


> Which is within 49990's range (+/-5V to +/-18V) as far as voltage.


 
  ahh yes, i misread the other post as max +/-5 no minimum


----------



## WiR3D

Quote: 





purpleangel said:


> The Essence STX (& ST) comes with three dual channel DIP-8 sockets.
> I'm using 3 AD797BRs in mine
> The LME49990 seems to be well liked.


 
  Its probably my fault are you using the AD797, it just sounds so good, but don't be surprised when they break from all the oscillation. 
  I have said before for my STX the following are on my list:

 LME49990
 OPA1612
 HA5002
 AD8599


----------



## PurpleAngel

Quote: 





wir3d said:


> Its probably my fault are you using the AD797, it just sounds so good, but don't be surprised when they break from all the oscillation.
> I have said before for my STX the following are on my list:
> 
> LME49990
> ...


 
  I ordered a 10 pack of soldered AD797BRs, so I still have 7 spare ones to use as replacements.


----------



## WiR3D

Quote: 





purpleangel said:


> I ordered a 10 pack of soldered AD797BRs, so I still have 7 spare ones to use as replacements.


 
  Now that is planning


----------



## harryyeo

Quote: 





wir3d said:


> Its probably my fault are you using the AD797, it just sounds so good, but don't be surprised when they break from all the oscillation.
> I have said before for my STX the following are on my list:
> 
> LME49990
> ...


 
   
   
  For the HA5002 to be used as a buffer in STX, should it be obtained as a dual or a single? (if theres even a dual)


----------



## SpudHarris

Don't think you can get it as a dual. Only ever seen it as a single and the adapter is not standard either as the bottom of the PCB has specific smd resistors in place. Got 8 of them off HiFlight (Ron Kerlin - Opamp Guru)


----------



## harryyeo

Quote: 





spudharris said:


> Don't think you can get it as a dual. Only ever seen it as a single and the adapter is not standard either as the bottom of the PCB has specific smd resistors in place. Got 8 of them off HiFlight (Ron Kerlin - Opamp Guru)


 
   
   
  I see.
  So I'll have to ask HiFlight about the making and shipping of it.
  Will be getting more than 1 as it won't make sense getting a busy man to make just a single piece and ship it over to Southeast Asia.


----------



## genclaymore

Any of you guys know of a dual channel op-amp that is Transparent, have a wide sound stage/sound imaging while being neutral or if I even wording it correctly, I mention dual as I can't Fit Two dual to single dip-8 adapters in the I/V at the same time.


----------



## WiR3D

Quote: 





genclaymore said:


> Any of you guys know of a dual channel op-amp that is Transparent, have a wide sound stage/sound imaging while being neutral or if I even wording it correctly, I mention dual as I can't Fit Two dual to single dip-8 adapters in the I/V at the same time.


 
  THS4032
  or 2x SOIC LME49990


----------



## stv014

Quote: 





wir3d said:


> Its probably my fault are you using the AD797, it just sounds so good, but don't be surprised when they break from all the oscillation.


 
   
  Note that the oscillation (if any) might also be amplified and output by the TPA6120. I am not sure if there is any lowpass filtering between the I/V stage and the headphone output, but it may very well be that there is none, and the TPA6120 has very high bandwidth. Simplified (incomplete) schematics of how I think one channel of the analog outputs of the Xonar STX is implemented:
   

  The graphs at this thread do confirm that the line output indeed has more high frequency roll-off (due to the ~190 kHz lowpass filter in the buffer stage). Interestingly, the headphone output is fully DC coupled, so it is possible for (buggy?) software to output DC to the headphones.


----------



## WiR3D

Quote: 





stv014 said:


> Note that the oscillation (if any) might also be amplified and output by the TPA6120. I am not sure if there is any lowpass filtering between the I/V stage and the headphone output, but it may very well be that there is none, and the TPA6120 has very high bandwidth. Simplified (incomplete) schematics of how I think one channel of the analog outputs of the Xonar STX is implemented:
> 
> 
> The graphs at this thread do confirm that the line output indeed has more high frequency roll-off (due to the ~190 kHz lowpass filter in the buffer stage). Interestingly, the headphone output is fully DC coupled, so it is possible for (buggy?) software to output DC to the headphones.


 
  Now that is not good news....


----------



## stv014

Quote: 





wir3d said:


> Now that is not good news....


 
   
  Well, I am not sure if oscillation in the I/V stage is dangerous to the headphone amplifier, and there are some unmarked passive components between the 10 Ω output resistors and the output jack (see picture here) for RF filtering, so I do not know what load impedance the TPA6120 sees in the MHz range. But it is possible.


----------



## WiR3D

Quote: 





stv014 said:


> Well, I am not sure if oscillation in the I/V stage is dangerous to the headphone amplifier, and there are some unmarked passive components between the 10 Ω output resistors and the output jack (see picture here) for RF filtering, so I do not know what load impedance the TPA6120 sees in the MHz range. But it is possible.


 
  Just adds more variables into my equation to determine what killed TPA6120 the thanks for the information as always.


----------



## hekeli

Quote: 





formula1 said:


> Do you guys notice the difference between A and B track?
> http://bursonaudioblog.blogspot.com/2012/02/marantz-cd72-hd-opamp-mod-with-sample.html
> 
> Been considering to mod my CDP with their opamps.
> Thanks.


 
   
  Can someone give me a detailed explanation what to listen for? I've been going over and over and can't hear a single bit of difference. Maybe I'm just untrained, deaf or then the opamp differences are so small I couldn't care less.


----------



## AKG240mkII

Quote: 





hekeli said:


> Maybe I'm just untrained, deaf or then the opamp differences are so small I couldn't care less.


 
  I couldn't care less .
  IMO, IF you can hear a difference ( and sometimes you can ),
  it's because the circuit-design isn't suitable for the op-amp in question (or vice-versa) .
   
  EDIT : Or it could be REALLY OLD op-amps, from the 1960's/70's ..
  Some of them where absolutely horrible !


----------



## GaToMaLaCo

Quote: 





hekeli said:


> can someone give me a detailed explanation what to listen for? I've been going over and over and can't hear a single bit of difference. Maybe I'm just untrained, deaf or then the opamp differences are so small I couldn't care less.


 
  Same here... i couldnt hear any significant difference. And when i mean significant i mean significant.


----------



## qusp

Quote: 





stv014 said:


> Note that the oscillation (if any) might also be amplified and output by the TPA6120. I am not sure if there is any lowpass filtering between the I/V stage and the headphone output, but it may very well be that there is none, and the TPA6120 has very high bandwidth. Simplified (incomplete) schematics of how I think one channel of the analog outputs of the Xonar STX is implemented:
> 
> 
> The graphs at this thread do confirm that the line output indeed has more high frequency roll-off (due to the ~190 kHz lowpass filter in the buffer stage). Interestingly, the headphone output is fully DC coupled, so it is possible for (buggy?) software to output DC to the headphones.


 
  do you know how to read schematics? above, there is a low pass RC filter in the negative feedback loop of the NJM which are the IV stage and there is a further low pass in the line out, neither are anywhere near anything that could be defined as a high frequency rolloff. 190khz is far above anything any speaker, headphone or ear is going to process, there is no signal to roll off, just the intended RF filter. there is not even any content up there, its just to prevent RFI and aliasing (artifacts from the oversampling filter) or glitch energy from the dac or environment from getting through and exciting HF oscillation. the software will not have anything to do with it, the use of improperly implemented AD797 will.
   
  apologies if i've missed posts that explain/recognize the above. you can indeed kill the buffers with oscillation, perhaps if they arent heatsinked enough to cope with exceeding the SOA with amplified DC. DC can build up on the gates until it is higher than the max voltage. seen it, done it. I was using an instrumentation amp I cobbled together with 3 opamps to measure and amplify the difference in voltage of an AC sinewave between the gate and source of some mosfets I was matching; to increase the accuracy of the reading on my meter by allowing measuring a few Volts, rather than a few mV. this was matching for transconductance for my IV stage
   
  the AC signal I was measuring was riding on DC, in a perfect world the DC would have cancelled out as it was the same on both inputs, but as we know its not a perfect world and it built up on the gates. luckily they were just some old LT1028 dip8 spares


----------



## hungryhungryzit

I've got the LME49990 in the I/Vs on my Titanium HD. Any recommendations for the buffer? Looking to add a tinge more bass without hurting the detail and transparency.


----------



## PurpleAngel

Quote: 





hungryhungryzit said:


> I've got the LME49990 in the I/Vs on my Titanium HD. Any recommendations for the buffer? Looking to add a tinge more bass without hurting the detail and transparency.


 
  Just get a third LME49990, I believe it's a little safer to get all matching op-amps.


----------



## hungryhungryzit

Quote: 





purpleangel said:


> Just get a third LME49990, I believe it's a little safer to get all matching op-amps.


 
  Would be 2, dual buffers, and in that case I don't need to get anything... I don't think. People keep saying the headphone out on the Titanium HD doesn't use the buffers. I got around that with a RCA adapter figuring since it doesn't have a dedicated amp it would deliver the same power over both, which it did. I'll just stick with the headphone output if there's nothing worth trying.


----------



## genclaymore

The headphone out on the TI HD doesn't use the buffers, only the RCA out on the card use all the op-amps. While headphone out only uses the Two I/v sockets.


----------



## stv014

Quote: 





qusp said:


> do you know how to read schematics?
> [...]


 
   
  Maybe you should know how to read an entire post in context before posting corrections to it to prove how much smarter you are. 
	

	
	
		
		

		
			





 Welcome to my block list.


----------



## qusp

haha i'm crushed… bye bye
   
  it was a genuine question, I had to ask because you didnt really make a great deal of sense. wasnt sarcasm, the line above is an example of sarcasm. I asked as a basis for what came after, this thread in particular gets a lot of people who do not know, but have gleamed a lot of info about the circuit from reading posts.


----------



## kiteki

hekeli said:


> formula1 said:
> 
> 
> > Do you guys notice the difference between A and B track?
> ...


 
   
  So, how exactly are you supposed to hear the difference between op-amps, when they're recorded?
   
  Aren't you listening to the 10 cent op-amp in your iPod Shuffle, or the LME49990 in your NAD M51, irrespective to any recording you're listening to?


----------



## hekeli

Quote: 





kiteki said:


> So, how exactly are you supposed to hear the difference between op-amps, when they're recorded?


 
   
  Obviously there has to be a clear difference if Burson and some random guy hype it so much?


----------



## kiteki

hekeli said:


> >
> 
> 
> 
> ...


 
   
  I think you'll find your answer on page 105 in this document - http://www.sg-acoustics.ch/analogue_audio/ic_opamps/pdf/opamp_distortion.pdf,
   
  and here - http://www.audio-gd.com/Pro/diy/OPA/OPAEN.htm.
   
   
  I think if you compare OPA-MOON and the AD8610 / AD8620, you will hear a "clear difference", naturally this difference is dependant on your perceptivity and how revealing your equipment is, yet it's a much more important difference than what cables or power conditioners can offer you.
   
  The difference is subtle like 5%, but sometimes 5% is all that's necessary to lift a digital veil, or a 5% enhancement in detail, like cleaning a window or polishing a diamond, in which case the emotional reward and involvement factor will be there.
   
  Some people say it's all marketing, but they have no idea what they're talking about or they're just deaf - all op-amps look exactly the same and my favorite sounding one costs around $5.  That's like a cheeseburger for high fidelity.


----------



## michelino

Hi everybody!
  This thread is sooo long (277pages  ) so I want to ask you what opamp should fit better in my Marantz CD5003... The stock are SOIC8 njm2068, one per channel. I've tested opa2107 and opa1612. The 1612 is way more detailed respect to the 2107, more analytical and alive, with a better bass (bigger and more controlled), but I miss the brighter high frequencies of the 2107.
  I've got on my hand LM4562, OPA2211, OPA1642, OPA2132 and I'm waiting AD8599 and AD8620 samples. What should I try?
  Thanks


----------



## Tommy Thong

michelino said:


> Hi everybody!
> This thread is sooo long (277pages  ) so I want to ask you what opamp should fit better in my Marantz CD5003... The stock are SOIC8 njm2068, one per channel. I've tested opa2107 and opa1612. The 1612 is way more detailed respect to the 2107, more analytical and alive, with a better bass (bigger and more controlled), but I miss the brighter high frequencies of the 2107.
> I've got on my hand LM4562, OPA2211, OPA1642, OPA2132 and I'm waiting AD8599 and AD8620 samples. What should I try?
> Thanks




just try opa1662 (if you want something smooth on mids) or lm4562ma (nice on tops freq & thigh bass) but changing soic opamp is tricky


----------



## Edifier12

Hi, Sorry for the laziness of not going through all 277 pages worth of information. I basically have a Sennheiser HD598 (rated at 50ohms?) connected to the Asus Xonar Essence STX. Mainly use them for gaming, then music and movies. Looking for a good all around opamp rolling without really compromising on bass or tremble as much as possible. Just want a good balance replacement to the stock really.
   
  What would you guys recommend  ? I've seen recommendation for the LME49860NA and the LME49720HA and such, then there are all these other different one as well... need some help deciding thanks lol.


----------



## WiR3D

Quote: 





edifier12 said:


> Hi, Sorry for the laziness of not going through all 277 pages worth of information. I basically have a Sennheiser HD598 (rated at 50ohms?) connected to the Asus Xonar Essence STX. Mainly use them for gaming, then music and movies. Looking for a good all around opamp rolling without really compromising on bass or tremble as much as possible. Just want a good balance replacement to the stock really.
> 
> What would you guys recommend  ? I've seen recommendation for the LME49860NA and the LME49720HA and such, then there are all these other different one as well... need some help deciding thanks lol.


 
  AD797 (could be unstable and eventually fail, but the best clarity), LME49990 - not a single complaint, almost equal to the AD797, and then the THS4032 - a smoother sound, with probably the best imaging, but SLIGHTLY smaller soundstage compared to the AD797.
   
  The entire LME49720 based range is a compromised design.


----------



## PurpleAngel

Quote: 





edifier12 said:


> Hi, Sorry for the laziness of not going through all 277 pages worth of information. I basically have a Sennheiser HD598 (rated at 50ohms?) connected to the Asus Xonar Essence STX. Mainly use them for gaming, then music and movies. Looking for a good all around opamp rolling without really compromising on bass or tremble as much as possible. Just want a good balance replacement to the stock really.
> 
> What would you guys recommend  ? I've seen recommendation for the LME49860NA and the LME49720HA and such, then there are all these other different one as well... need some help deciding thanks lol.


 
  The LM4652 (STX's buffer op-amp), LME49720NA & LME49860NA are the same op-amp, the LME49860NA is just the cherry pick (tested with better voltage range).


----------



## wakibaki

Quote: 





zilch0md said:


> Warning:  The LME49990 is a JFET op-amp


 
   
  Is it? It doesn't say so anywhere in the datasheet.
   
  Jfet opamps are usually characterised by an input bias current in the picoamp range. The LME49990 has an input bias current in the range 30-1000nA which is more typical of a bjt input.
   
  See page 190 of Horowitz & Hill.
   
http://books.google.co.uk/books?id=bkOMDgwFA28C&pg=PA190&lpg=PA190&dq=typical+bjt+input+opamp+bias+current&source=bl&ots=F3cnVDc0Yw&sig=u90V9iQ3wq7nAJFZvfiSi9mnRkw&hl=en&sa=X&ei=MUFiUMSGJoiWhQfmz4H4Cw&redir_esc=y#v=onepage&q=typical%20bjt%20input%20opamp%20bias%20current&f=false
   
  w


----------



## zilch0md

Quote: 





wakibaki said:


> Is it? It doesn't say so anywhere in the datasheet.
> 
> Jfet opamps are usually characterised by an input bias current in the picoamp range. The LME49990 has an input bias current in the range 30-1000nA which is more typical of a bjt input.
> 
> ...


 
   
  Hi wakibaki,
   
  You're probably right.  I don't remember where I had heard that, and having just spent about 10 minutes looking, all I could find was a reference indicating that the 49880 (not the 49990) is a jfet dual.
   
  Thanks!
   
  Mike


----------



## Edifier12

@ WiR3D Hi thanks for the reply , I was considering the LME49990 too, but as i've seen, they're a SOIC-8 type is it?
   
  so I was wondering if i need 1 per dip-8 adapter? or 2? I've seen someone on the forum selling one to europe, and they linked a ebay page someone selling 2 of them soldered on top and on the underside of a PCB adapter?
   
  Can I just get 2 and solder them onto 2 separate adapters? Are there even adpaters that doesn't require soldering at all?
  Quote: 





wir3d said:


> AD797 (could be unstable and eventually fail, but the best clarity), LME49990 - not a single complaint, almost equal to the AD797, and then the THS4032 - a smoother sound, with probably the best imaging, but SLIGHTLY smaller soundstage compared to the AD797.
> 
> The entire LME49720 based range is a compromised design.


 
   
  Quote: 





purpleangel said:


> The LM4652 (STX's buffer op-amp), LME49720NA & LME49860NA are the same op-amp, the LME49860NA is just the cherry pick (tested with better voltage range).


 
  @PurpleAngel thanks for your quick reply too man, is the LM4652 the stock buffer op-amp? I've read on here that changing the buffer on my Essence STX wouldn't really do much for my headphone but I'm guessing they might for my speaker outlet?
   
  so in that case if i was to choose LME 49990 as the I/V right... what would be a logical ideal choice to use as buffer to compliment the 49990? 49860NA perhaps or even another model of brand even?
   
   
  Once again guys, thanks so much for all these quick responses, you guys are saving lives here lol.


----------



## WiR3D

Quote: 





edifier12 said:


> @ WiR3D Hi thanks for the reply , I was considering the LME49990 too, but as i've seen, they're a SOIC-8 type is it?
> 
> so I was wondering if i need 1 per dip-8 adapter? or 2? I've seen someone on the forum selling one to europe, and they linked a ebay page someone selling 2 of them soldered on top and on the underside of a PCB adapter?
> 
> ...


 
  you need x2 per adapter, check ebay, they make it for you. There are a few sellers. 
   
  also the 49860 is based on the 49720, which is flawed. they are cheap upgrades though. but not in the LME49990, AD797, THS4032 range.


----------



## Edifier12

Quote: 





wir3d said:


> you need x2 per adapter, check ebay, they make it for you. There are a few sellers.
> 
> also the 49860 is based on the 49720, which is flawed. they are cheap upgrades though. but not in the LME49990, AD797, THS4032 range.


 
  Thanks! So basically, I just need 3 x 49990 or I can experiment the buffer with others you've mentioned? Would the buffer affect my speakers output? Currenctly using Edifier s730 speakers
   
   
   
  This looks about right WiR3D? http://www.ebay.com/itm/2PCS-LME49990MA-on-SOIC-DIP-adapter-DIP8-Socket-/320863638478?pt=US_Amplifier_Parts_Components&hash=item4ab4f693ce


----------



## WiR3D

Quote: 





edifier12 said:


> Thanks! So basically, I just need 3 x 49990 or I can experiment the buffer with others you've mentioned? Would the buffer affect my speakers output? Currenctly using Edifier s730 speakers
> 
> 
> 
> This looks about right WiR3D? http://www.ebay.com/itm/2PCS-LME49990MA-on-SOIC-DIP-adapter-DIP8-Socket-/320863638478?pt=US_Amplifier_Parts_Components&hash=item4ab4f693ce


 
  yes, the buffer is for the speakers only. 
   
  And lol thats the seller I use. They package stuff very well. And yes its the right one.


----------



## Edifier12

Quote: 





wir3d said:


> yes, the buffer is for the speakers only.
> 
> And lol thats the seller I use. They package stuff very well. And yes its the right one.


 
  sweeeet man lol, I'm going for it! thanks a lot for the help!!


----------



## WiR3D

Quote: 





edifier12 said:


> sweeeet man lol, I'm going for it! thanks a lot for the help!!


 
  WAIT!!! I was wrong - I hate their naming scheme.
   
http://www.ebay.com/itm/1PCS-Dual-Mono-LME49990MA-replace-OPA2604-NE5532-TL072-/320863640326?pt=US_Amplifier_Parts_Components&hash=item4ab4f69b06
   
  thats the correct one


----------



## Edifier12

Quote: 





wir3d said:


> WAIT!!! I was wrong - I hate their naming scheme.
> 
> http://www.ebay.com/itm/1PCS-Dual-Mono-LME49990MA-replace-OPA2604-NE5532-TL072-/320863640326?pt=US_Amplifier_Parts_Components&hash=item4ab4f69b06
> 
> thats the correct one


 
  haha dude, lucky I messaged him to double check, i thought the name was a little off, well since you replied now and are sure I'm gonna just go ahead and buy it haha, cheers man, thanks for the help
   
  haha damn, these things are a bit dear for 3 aren't they


----------



## kazaakas

Hey peeps,
   
  I'm struggling to decide which opamps I should get for my titanium HD, was leaning towards the LME49990 until I got these 2 responses in a thread I made.
   
  As the stock opamps are known to be kind of a let-down, I was wondering what else there is to choose, maybe OPA627 or OPA827?
   
  I have to note I did a LOT of searching but on this card speficifially I can't seem to find any common recommendations.
   
  Another thing I was wondering, what if I decide to take SOIC opamps for my titanium HD, would I have to use a dual to single adapters for both the two I/V slots and the two buffer slots?
  I can't imagine I'd need 8 opamps in total for one card.
   
  By the way I'll connect the RCA outputs to a headphone amp so the buffer opamps will not be bypassed if I'm not mistaken.


----------



## PurpleAngel

Quote: 





kazaakas said:


> Another thing I was wondering, what if I decide to take SOIC opamps for my titanium HD, would I have to use a dual to single adapters for both the two I/V slots and the two buffer slots?
> I can't imagine I'd need 8 opamps in total for one card.


 
  SOIC op-amps need to be soldered to something, the DIP-8 sockets (like in the Titamium HD) are designed for removeable op-amps.
  If you used all SOIC single channel op-amps, you would need 6 op-amps, with 4 op-amps soldered on to 2 dual SOIC to DIP-8 adapters and the last 2 op-amps soldered on to 2 single SOIC to DIP-8 adapters


----------



## kazaakas

Quote: 





purpleangel said:


> SOIC op-amps need to be soldered to something, the DIP-8 sockets (like in the Titamium HD) are designed for removeable op-amps.
> If you used all SOIC single channel op-amps, you would need 6 op-amps, with 4 op-amps soldered on to 2 dual SOIC to DIP-8 adapters and the last 2 op-amps soldered on to 2 single SOIC to DIP-8 adapters


 
  Thanks!
   
  So the opamps in the buffer stage only need one channel?
   
  ie: 2 of these for I/V: http://www.ebay.com/itm/1PCS-Dual-to-Mono-LME49990MA-replace-OPA2604-NE5532-TL072-/320863640326
  and one order of these (2 adapters) for buffers: http://www.ebay.com/itm/2PCS-LME49990MA-on-SOIC-DIP-adapter-DIP8-Socket-/320863638478
   
  Also, does anyone else has some intel about how these perform on the Titanium HD?


----------



## PurpleAngel

Quote: 





kazaakas said:


> So the opamps in the buffer stage only need one channel?
> ie: 2 of these for I/V: http://www.ebay.com/itm/1PCS-Dual-to-Mono-LME49990MA-replace-OPA2604-NE5532-TL072-/320863640326
> and one order of these (2 adapters) for buffers: http://www.ebay.com/itm/2PCS-LME49990MA-on-SOIC-DIP-adapter-DIP8-Socket-/320863638478
> Also, does anyone else has some intel about how these perform on the Titanium HD?


 
  The buffer is a dual channel, but uses one single channel op-amp in each of the two separate buffer DIP-8 sockets.
  Those are the correct op-amp packages to get.
  I have no idea on how well they work in the TiHD.


----------



## kazaakas

Thanks, I got that, though I still wonder why the I/V section would have the need for two dual channel opamps? That makes a total of four channels... I'm confused!


----------



## qusp

it needs 4 channels in the IV section because its a balanced dac and thus needs Left +/- and Right +/-.

lme49990 isnt the greatest chip for IV, or buffer. it'll work and its a great chip, but its not really fast enough for IV in modern dacs IMO. its pretty current limited for buffering, but it depends on your reason for the buffer, if they will be driving headphones directly then I would choose another opamp. I love them, but I would be more likely to use a current feedback opamp (would require other mods), or perhaps an opa827 for IV followed by a line stage with 4999 and a buffer wrapped in the lme49990 feedback loop.


----------



## zilch0md

qusp,
   
  Not wanting to interrupt, but as a side question, a couple of days ago I replaced the 4x HA5002 buffers in my iBasso PB2 with 4x AD797 as buffers, still using 4x LME49990 singles in L/R.  Everything seems to be running cool, with no evidence of oscillation.  The sound is warmer yet more detailed than with the HA5002 buffers.  
   
  Have you ever tried this combination (and/or do you have any comments that come to mind)?
   
  Thanks!
   
  Mike


----------



## smengy1

Well I have done a bunch of recording with my Auzentech Meridian 2.1g and it sounds incredible with the dual LME 49710HA s in it!!!
	

	
	
		
		

		
			




  I use Foobar for playback and it gives really excellent results.  Still the 49710's are harsh in the treble department.  I did not use a "flat"
  RIAA curve when recording.  I used the bass and treble on my pre amp to add in bass and treble to my liking.  In the Auzentech controll
  panel there is a thing called Bass Extender or something like that where you controll the crossover point.  It adds sweeteness to the treble.
  Still the Ortofon x5-mx extracts alot of treble detail!    So I was looking for a mellower opamp.
   
  Now I am split between OPA637AM and a OPA2111(both are to-99's).  I was wondering with the 637AM if it is better sounding than a AU per se,
  and better than a opa2111.  I have also heard it said the opa637sm's are really harsh sounding.  I really enjoy the soundstaging of the LME49710HA's tho,
    what opamps in that LME family sweeten the sound up??
   
  I found a site where they said the AM HA etc were ratings,  the A's being the worse and the H's better quality.   I wish I could find it again
  so I could post the link.
   
  I do love the sound of the LME49710HA's tho!   The soundstage is very 3d.  When I switch to Digital processing on the Audio card,  the
  sound does warm up a bit,  and add in the Bass Crossover thing and its very nice.  Still the Analog section really has the best quality sound.
  It is just drier and less warm than the digital processing. 
   
  I was also thinking of buying one of these to put on the line to the amp. 
  http://secure.oatleyelectronics.com//product_info.php?products_id=922&osCsid=75d0cc0ac13f60577205ee57ec321aaf
   
  Here is a neat headphone kit too:
  http://secure.oatleyelectronics.com//product_info.php?products_id=885
   
  OK opinions please!!!!!
   
  Oh and let me add,  I dont listen with headphones!!!  I know this is headphoner site,  but still you are only people talking about opamps,  so here i be!!!!


----------



## ecohifi

Quote: 





wir3d said:


> you need x2 per adapter, check ebay, they make it for you. There are a few sellers.
> 
> also the 49860 is based on the 49720, which is flawed. they are cheap upgrades though. but not in the LME49990, AD797, THS4032 range.


 
  Please claify how the 49860 is based on the 49720 and that it is flawed????


----------



## PurpleAngel

Quote: 





ecohifi said:


> Please claify how the 49860 is based on the 49720 and that it is flawed????


 
  The LM4652, LME49720 & LME49860 are the same op-amp.
  When the LME49720 is tested at the factory and the op-amp can handle a greater voltage range, it's labeled a LME49860NA.


----------



## majkel

purpleangel said:


> ecohifi said:
> 
> 
> > Please claify how the 49860 is based on the 49720 and that it is flawed????
> ...


Yeah, sure. And when it gets fried, it's labeled LME49720. Please.


----------



## zilch0md

I don't know if that's true, but it's analogous to how Intel used to rate the clock speeds of their processors, back in the early days of Intel's x86 processors.  
   
  I know that companies like Northgate, who were selling "IBM clones" would pay Intel more than the price of a 386-16 processor, for reject 386-20 chips that could be clocked at 18 MHz (but not quite 20 MHz).  Northgate would sell their machines as 386-16 machines, but they would clock the CPU at 18 MHz and thus, their machines would benchmark as being much faster than the typical 16 MHz machine.  
   
  They were doing this BEFORE Intel officially released the 386-20 (by putting reject 386-20s on their motherboards and marketing their machines as the world's fastest 386-16s).  Later, when Intel finally worked the kinks out of the 386-20 design, actual 386-20 CPUs hit the market, and Northgate repeated the strategy, buying Intel's next rejects, but marketing them as "faster" 386-20's.  (Then the 25, the 33, and the 50...)
   
  This was no secret.  Anyone who opened a Northgate machine at the time could see the 386 CPU, silk-screened with the markings of the next generation of chip, but with a permanent marker text applied by hand:  "18 MHz" (on a chip silk screened as a 386-20, for example - at a time when 386-20 machines were not yet being sold).
   
  Mike


----------



## FritzS

What did you think about LME49713HA as driver? They easily drives 150Ω loads. Two LME49713HA in parallel should drive the most headphones.
   
  Have anyone experience with Analog Devices AD815AYS (headphone driver), TI OPA1632, TI OPA1612?


----------



## qusp

cant really remember ad815, but plenty of experience with opa1612 and opa1632. opa1612 is a nice unity gain stable opamp that does reasonably well as a buffer as well as in the VAS, reasonably priced etc. if using it alone its the better choice, but if there is a buffer afterwards to drive the headphones, or you are using them for line out, driving fairly high load impedance; then I would choose the newer opa1642, it doesnt have much current capability though so wont do well with low impedance loads. 

the opa1632 is a fully differential balanced in, balanced out super symmetry opamp, an excellent chip, but wont work in place of the others, or in any of these designs even if balanced, unless you modify the PCB. its a fantastic chip when suitable and I use it extensively, but its not any good for opamp rolling because of this.

the rumour of these chips all being the same is just that, rumour, the spec is similar and they are made with a similar process but thats where it ends. the rumour was started by someone who left National long before they were acquired by Ti and was later denied by another employee, but it has spread throughout the net, repeated by people who dont have any way of knowing one way or the other.

@smengy
not sure where you may have read about a comparison between any HA suffix and an SM suffix, thats funny, if you did the person was talking out their ass … They are simply suffixes to describe grading and physical package (metal can to-99, DIP8, SOIC8 etc) HA and SM are metal cans from different companies, well not now, now national has been acquired by Ti. HA is one suffix used to signify a metal can part designation from National; SM or AM is a metal can suffix from Ti (SM is the highest grade milspec). SM harsh and the soic not? lol why must people persist in making stuff like that up:rolleyes:


----------



## ecohifi

Quote: 





qusp said:


> cant really remember ad815, but plenty of experience with opa1612 and opa1632. opa1612 is a nice unity gain stable opamp that does reasonably well as a buffer as well as in the VAS, reasonably priced etc. if using it alone its the better choice, but if there is a buffer afterwards to drive the headphones, or you are using them for line out, driving fairly high load impedance; then I would choose the newer opa1642, it doesnt have much current capability though so wont do well with low impedance loads.
> the opa1632 is a fully differential balanced in, balanced out super symmetry opamp, an excellent chip, but wont work in place of the others, or in any of these designs even if balanced, unless you modify the PCB. its a fantastic chip when suitable and I use it extensively, but its not any good for opamp rolling because of this.
> the rumour of these chips all being the same is just that, rumour, the spec is similar and they are made with a similar process but thats where it ends. the rumour was started by someone who left National long before they were acquired by Ti and was later denied by another employee, but it has spread throughout the net, repeated by people who dont have any way of knowing one way or the other.
> @smengy
> not sure where you may have read about a comparison between any HA suffix and an SM suffix, thats funny, if you did the person was talking out their ass … They are simply suffixes to describe grading and physical package (metal can to-99, DIP8, SOIC8 etc) HA and SM are metal cans from different companies, well not now, now national has been acquired by Ti. HA is one suffix used to signify a metal can part designation from National; SM or AM is a metal can suffix from Ti (SM is the highest grade milspec). SM harsh and the soic not? lol why must people persist in making stuff like that up:rolleyes:


 
  Nice down to earth post qusp,
  Why does it always take someone from downunder to reafirmed the truth?
   
  Regards
   
  echohifi
  (Posting from Guandzhou China on holidays but reside in Melbourne Australia)


----------



## smengy1

WEll look what I found,  the "Quality"  grading i was talking about.  Ahh who knows if it means anything
   
  i had asked them directly about the difference in their 637 models, the $70 vs the $250, and heres what i was emailed back about the product codes-

 "The first letter, A','B','S' means OPAMP Grade' and the quality is better in following order.
 A' < B' < S'
 The second letter, U','M','P' means package type'.
 P: DIP type
 U: SMD(SOIC-8) type
 M: Metal Can type(It protects against the noise and electricity)
 The 637 line's feature is similar, but the quality is different.
 Therefore the OPA637SM type is the highst price as the best sound quality."

 so i have the 637au which came out two months ago, and this past week they have the new 637sm now for 4x the price. i wonder who will ever be able to compare the two with a good system. i run my prelude into the rotel 1085 5ch digital amp and wonder if there would be any difference.
   
  So can anyone reccomend anything warmer and detailed and nice Bass for a Auzentech soundcard?
   
  I have LME49710 HA?
   
  Ignored as usual.


----------



## kiteki

Err, they are some pretty high prices there for the OPA627 variants.  Yes, it's a very popular chip with due reason, it's not _amazing _though, and I find that other chips have nicer highs, there is some kind of veneer on the highs of the OPA627, it's like it's 'painted' and can't break free into an open sky, it's annoying once you notice it _(unless I'm just not supplying it with the right DAC or +-15V or whatever it needs)._
   
  The OPA827 and OPA1612 are nice and neutral chips while sounding analog at the same time but they don't have any _character _like the OPA627 has, they sound like empty hospitals, honestly.  Chips with character plz.


----------



## FritzS

Now I use two OPA627  in my (old but good) WNA MKII headphone amp, with best results
   
  You can see here all the OPA's I test
http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit/750


----------



## kiteki

> Originally Posted by
> 
> AD797.


 
   
   
  Keep in mind AD797ANZ and AD797BR sound quite different........................................
   
  Currently, I'm finding the latter excellent as a line-out driver.
   
   
   
  This DAC has me curious, it's using ESS ES9018 in current-out mode, can I connect the line-out on it directly to my amplifier without issue?  Any flaws it may have?  http://www.audio-gd.com/Pro/Headphoneamp/NFB11.32/*NFB11.32EN*.htm


----------



## kiteki

fritzs said:


> Now I use two OPA627  in my (old but good) WNA MKII headphone amp, with best results
> 
> You can see here all the OPA's I test
> http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit/750


 
   
  It's a fantastic op-amp, perhaps one of the best ever made, however right now I'm preferring the more pristine unfettered highs of the AD823!


----------



## FritzS

Quote: 





kiteki said:


> It's a fantastic op-amp, perhaps one of the best ever made, however right now I'm preferring the more pristine unfettered highs of the AD823!


 
   
  I am going the reverse way in my GSP Audio Solo, I use a metal can OPA LME49720HA instead of the AD823 with better performance.
   
  Otherwise in WNA MKII I had with LME49710 not the best results.


----------



## kiteki

I suppose OPA627, AD823 and LME49720 etc. will sound a little different in different amplifiers, due to buffers, capacitors, circuit layout, voltage supply and that jazz... but how about the sound of the DAC and the line driver before the amplifier?
   
  ...only AD797BR as the line driver really unlocked the potential of AD823 for me !!
   
   
  Hmmmm I'm wondering if the ESS ES9018 in current-out mode could be a nice alternative for DAC and line-out to amplifier fun?


----------



## qusp

smengy1 said:


> i had asked them directly about the difference in their 637 models, the $70 vs the $250, and heres what i was emailed back about the product codes .../snip




and what part of my post made you think I wasnt aware of that? 



			
				qusp said:
			
		

> They are simply suffixes to describe grading and physical package (metal can to-99, DIP8, SOIC8 etc)




the thing is, whoever that idiot was, said that the opa637SM was 'harsh' when its the top spec part, is either attributing something else to the opamp, using it incorrectly (it needs to be used at 5x gain at least to be stable), or just making stuff up.

it was probably the same person that said



> I found a site where they said the AM HA etc were ratings, the A's being the worse and the H's better quality. I wish I could find it again



this is the really stupid part, someone comparing AM and HA and saying A's were lower quality is just trying to sound smart, because they are the lowest spec metal can for 2 different companies and cannot even be compared, one is not even graded against the other. National and Ti used to be 2 different companies, only very recently Ti acquired National, but they are still not graded against one another. they do not make an OPA637HA and nor do they make an LME49710AM, so there is no basis for comparison.



> WEll look what I found, the "Quality" grading i was talking about. Ahh who knows if it means anythingwhat i was emailed back about the product codes-
> 
> "The first letter, A','B','S' means OPAMP Grade' and the quality is better in following order.
> 
> ...




the quality levels are not even really quality levels. to grade the parts they will just take a batch of the devices and bin them on performance in harsh environments, ie. how much they change/drift as they heat up (tempco: mostly if the parameters will drift in temperatures above 85 degrees....) they will call one lot SM, one lot BM and another AM based on the result. Because they have tested them they can then assure this level of performance/stability to customers, who may be using the parts in mission critical applications where lives, or large amounts of money are on the line if something goes wrong (like a plane or spaceship dropping out of the sky)

this process takes time and costs money, many will not even be tested because they know they wont sell as many SM parts, so there will be parts that could be graded SM in the stock sold as AM, as its not worth their time to test them, but they know they can call all of them at least AM. at the temperatures we use them at and the frequencies used in audio, we are not even close to stressing the lowest level.



> so i have the 637au which came out two months ago, and this past week they have the new 637sm now for 4x the price. i wonder who will ever be able to compare the two with a good system. i run my prelude into the rotel 1085 5ch digital amp and wonder if there would be any difference.




what? AU that came out 2 months ago? the opa637 datasheet was last updated in 2000 and released before that, I personally have a set that i've had for nearly 3 years.

 I can tell you without doing that test, forget it, hes gotta be having a laugh, some people are stupid, 250 is a joke, buy something else, buy a better amp. is that each or a pair? either is beyond crazy, but $250 each is criminal …



> So can anyone reccomend anything warmer and detailed and nice Bass for a Auzentech soundcard?
> 
> I have LME49710 HA?
> 
> Ignored as usual.




yes I ignored that, because i'm not sure they make high quality opamps wit da goodz kickin bazz... you are much better off adding a proper headphone buffer. I gather the dac section of the board is fairly well done, but the headphone amp could definitely use some work and swapping an opamp isnt going to fix it. what it needs for tight and controlled bass, is good high current and low output impedance headphone drive. 

or you could just use EQ to bump the bass....


----------



## qusp

kiteki:


there is no such thing as ESS 'current mode' its a term that is erroneously bandied around. the dac puts out all voltage into higher impedance loads and all current into zero impedance loads and a mix of the 2 at all the levels in between. I wouldnt go near the fun thing, or his ESS dac.

mate ARZ vs BRZ? hmm they sure dont measure any differently. I use the BRZ.... just because.... but I think any large difference is going to be in your mind.

I'll tell you what is interesting for AD797 fans who dont mind a bit of DIY, the designer of the chip, Scott Wurcer is currently working on a DIY project with some other notable designers!! They are developing a discrete high performance balanced Jfet input opamp design for audio and publicly too. Eventually there will be small PCBs made available; i'll probably start bread-boarding one of the versions this weekend. 

Its being designed to be small enough to plug into an opamp adapter, or close at least and not use hundreds of parts, just high performance using well matched low noise jfets and transistors. not a novice build if you have to do the matching, but if you can get the parts it probably wont be too difficult and performance should be superb! the parts will absolutely need to be matched, like the AD797 its going to be a very high performance and likely somewhat cranky thoroughbred, it will need good power supply too, as its PSRR wont be as good as an IC. 

heres an early version prototyped up by one of the members, there are parts on the other side too



perhaps with Scotts permission when something more concrete is ready, I will see if we can run a GB for kits over here, perhaps with the matched BF862 jfets or similar already soldered for those not confident with SMD. 

There will likely be either a matching buffer needed, or a higher current output buffer included in a modified design, if people want to drive low impedance headphones. so far the load impedance is only tested for 600 ohms and up. Its a general purpose audio opamp, not a headphone amp by itself, so could be teamed with lme49600/10, or simple class A discrete buffer/follower in a design, or without buffer in the line stage or IV stage of an existing design. 

i'm sure there will be a version made available that will drive lowZ, we have already been talking about it. its a way off yet and I have no claim to fame, i'm only involved as a hobbiest and big fan of Scotts (who is over the moon that this is happening!) 

 I cannot guarantee I can get permission to make this happen, but there WILL be PCBs at some point from someone, i'll make sure to update you guys when its ready. The design is being made publicly available, so I would think if I ask and as long as i'm not making a product with it, it should be ok. we'll see


----------



## kiteki

qusp said:


> kiteki: mate ARZ vs BRZ? hmm they sure dont measure any differently. I use the BRZ.... just because.... but I think any large difference is going to be in your mind.


 
   
  The ANZ and BR have different input offset voltage, input bias current, input offset current, different open loop gain and something about "plastic" versus "standard".
   
   
  I didn't test them with the same DAC so I'm not completely sure, could be a synergy issue but they don't seem to sound identical to me. =/
   
   
  Thx for the info on the DIY discrete coming up.
   
   
   


qusp said:


> there is no such thing as ESS 'current mode' its a term that is erroneously bandied around. the dac puts out all voltage into higher impedance loads and all current into zero impedance loads and a mix of the 2 at all the levels in between. I wouldnt go near the fun thing, or his ESS dac.


 
   
   
You said the ESS ES9018 sounds and measures better every time in 'current mode' using an external I/V.  http://www.diyaudio.com/forums/digital-line-level/190745-differences-between-voltage-dac-current-dacs.html#post2604083
   
   
  Why not go near the NFB-11.32?  I hope it's not Buffalo or AckoDAC favoritism ...


----------



## smengy1

Howdy!
    Yeah that was from a post that was rather old!  LOL!  Those prices were outdated.
  Just posted it for fun.  Nice Analysis!!
   
  So basically im lookin at either  LME49720HA ,  opa 627SM,  and OPA2111,  all to-99 cans.
   
  I have heard it said that the Burr Brown's are "warmer" sounding.
   
  I also saw some reviews about the LME49720HA sounding slightly warmer than LME49710ha.
   
  The Ortofon x5-mc I am using really extracts the highs from the music.
  But it also extracts alot of the stylus noise in the groove,  raspy sounding crap!!
   
  I can get rid of it with the Diamond Cut Audio I have with the crackle filter.
   
  Soundstage and imaging is great with LME49710HA.  Sometimes I can get 5 different channels playing back at once.  A center sound two inner stereo
  bands,  and one that is way to the outside of the inner bands.  It's very 3d and I like that.    So wondering if staying in the
  LME family will keep me happy?
   
  Dunno if getting one single opa2111 to test out Burr Brown Sound is wiser than getting two OPA627SM's?
   
  I dunno,  I don't have a engineering degree.   Its a sound card,  and I really listen to it through my desktop speakers, and a Marantz sr7300 into 3 pairs of speakers in series lol!!   It looks like top of Empire State Building,  3 speakers stacked on each other!!!  Auzentec made it with a really nice Analog recording sections.
  http://www.auzentech.com/site/products/x-meridian2g.php
   
  So i have Digital Dacs in Card,  and Digital Dacs I can turn on in the Amp,  along with Analog settings on both as well!!  Lots of settings!!!!
  Card does warm up in 48 and 44khtz digital passthrough on the sound card.  Bass extender sweetens the highs as well.
  Just the Analog section has best detail,  just is less "juicy" shall we say.
   
  So basically hmm......  whats warmer with good detail and Bass.   My mids are dry with the LME49710HA's thanks to the ORTOPHON,  but detail is incredible!!
  Definetly keepers for mastering vinyl!!! 
   
  I also modded my turntable wires with silver!! 
  http://www.vinylengine.com/turntable_forum/viewtopic.php?p=323623
   
  So that makes the trebles treblyer!!!  And the bass is so detailed its fantastic!!!
   
  Also this tube passthrough device I am thinking about as well.
  http://secure.oatleyelectronics.com//product_info.php?cPath=100_104&products_id=922
   
  And here is headphone one:
  http://secure.oatleyelectronics.com//product_info.php?cPath=100_104&products_id=885
   
  Thanks for chattin me up.....  Decisions decisions......


----------



## smengy1

Oh another quick question,  the LME49720HA needs a single or dual adapter?
   
  If im right the opa2111 is a single adapter. i.e. it is dual channel or dual output.  Not sure of the terms.
   
  And the opa627sm ineeds a dual to-99 adapter for stereo output in a dip8?


----------



## leeperry

Quote: 





smengy1 said:


> that makes the trebles treblier!!!


 
   
  It's called oscillation
	

	
	
		
		

		
			




   
  I dunno, try 2*OPA132U soldered onto adapters? or OPA2132P if you're not DIY savvy.


----------



## Currawong

Spoiler: For%20Kiteki%2C%20about%20the%20NFB-11



Kiteki: I had the original NFB-11. It was a basically good DAC, but a bit "flat" and un-musical sounding. For best results with the ES9018, as I found with DACs from other companies as well, it needed the best quality digital input circuitry, otherwise it ends up sounding flat and unnatural. I do know (though it is obvious, if you read the Audio-gd web site) that Kingwa has been working on improving the digital input of his DACs as well as the ES9018-based DACs. The one I have here with his latest USB implementation is the cheapest one, the NFB-16, which sounds very good, close to the quality of the Dragonfly. Going by my experiences, I'd take a fair bet that the direct-to-I2S USB implementation will have improved the sound quality significantly over the NFB-11 I had.


   
  The funny thing is I came to this thread to see about OPAMPs, because I was just about to get the Otomatsu amp out I built and run some OPAMPs through it, so I wanted to see what ones are being discussed at present.


----------



## kiteki

Are there any other alternatives under $600 using ESS ES9018?


----------



## qusp

Spoiler: Warning: Spoiler! more on the ESS theme for kiteki



you will notice I normally if I remember put inverted commas around 'current mode'. it is an unfortunate term used in the datasheet that has grabbed hold and is often used incorrectly, but its what people 'understand'. the ESS has a fairly low output impedance for a current source; only 195ohms (in stereo balanced mode). normally a current source has MUCH higher impedance. this means it doesnt take much impedance in the next stage to start it outputting a significant portion of its output as voltage. its a transition, there is no point where it just stops putting out current and starts putting out voltage. there is a point where its effectively all current and there is a point where its effectively all voltage, but most IV stages are somewhere in between. the ideal IV stage for it would have zero input impedance and then do the current to voltage conversion in the middle or output of the circuit. the closest we can really do is present it with a very high trans-conductance fet or transistor input, like the NTD1 that I use. bipolar transistors usually have higher trans-conductance (gM) than fets do, but I I have a personal preference for fets and there isnt much room for improvement past the -115dB THD+N i'm getting already with literally a couple of resistors and a couple of fets. an opamp can ,also be used of course

digital input has never been a strength over there at Audio-gd and that hasnt changed, but I think its much more than that, the decoupling caps are placed too far away, in a way they will be near useless, never-mind using pretty red film caps when npo ceramics right on the pins would be a much better choice. and PCB/Ground layout is a bit poor and he uses 'audiophile approved' 'audio grade' parts instead of high performance parts. the digital inputs use 2 separate unshielded wires running in parallel instead of coax or twisted pair, why? calling it a 75ohms coax input is misleading there is no value to doing this other than perhaps visual, which seems a theme. 

'Audio Grade' parts are often lower spec parts than the high spec industrial parts from the same manufacturer, like those from Nichicon, they make much higher performance caps than the KG/KZ range and they come with meaningful datasheets, unlike the KZ, which are nice enough caps and I might use them for signal coupling if I had to have a cap and couldnt use film, but for power supply decoupling, give me their excellent FP series polymers anyday

the continued use of certain other people's trademark names isnt cool either.
Buff III is a bit of a mess too, Buff II or of course Ackodac are less sprawling. for commercial dacs on par with AKD12/18 you are looking at pretty big dollars



the opa1652 is pretty sweet if you need a dual Currawong, but really its still hard to beat lme49990 for singles if youve not tried that.


----------



## smengy1

I found this little review and it helped greatly.
   
  http://www.xbitlabs.com/articles/multimedia/display/auzen-xfi-home-theater-hd_6.html#sect0
   
  After reading through it I went and ordered a LME49860 to try.  Said it almost beat
  a OPA637SM. 
   
  49990 I might try too.
   
  Still its weird,  the trebles seemed to have de harshed,  I think it's just my
  cartridge breaking in.  The bass output has risen,  and the treble is not so
  harsh.  I find it dependent upon when the Vinyl was pressed.  I guess it also
  depends on how it was recorded.  Songs like the Police ,  where that drummer
  is wailing on the high hat can become terrifying experiences!!  Really hot and ear
  cutting. 
   
  Earlier recordings with the 15degree cutting head angle are nice and never harsh,
  the later ones where they went to 20 degrees,  they can really have a lot of harshness in
  the treble.  It just depends at what level they are at in the recording mix.  up front or
  with effects and blended in lower.
   
  When I get the dispensable income I might try some other to-99 opamps. 
  I am starting to wonder if the lme49710HA's can really be beat.  When I put on
  the Auzentech bass Crossover thingy, it adjusts from like 60 to 250 htz,  it is like a tube amp has been turned on.
  It really sweetens the mix.   I just forgot to turn it on,  cause when I record I want a unbiased signal.


----------



## zilch0md

Hey qusp,
   
  Quote: 





qusp said:


> [snip]
> 
> ...for instance in my portable balanced dac-.amp i'm 'only' running a 4 series connected A123 LiFePO4 for a total of +/-6v6->7vdc, this is regulated down to +/-5.9vdc with a dual mono/bipolar supply and I challenge anyone to go past 60% with HD600. these batteries are capable of 140A bursts, thus I dont use them directly lol even though their noise and output impedance is lower than the regulators (2 x LTC3032)
> 
> [snip]


 
   
  This goes back a while, but reading this again, I'm very curious about the regulating, dual mono/bipolar supply that is sitting between your 4S LiFePO4 pack and your load.
   
  I have almost no DIY skills, but I'd like to get my hands on something, _anything_, that can be inserted (externally) between a LiPo pack and the power jack of an amp - to limit maximum possible current to about 3A.  Everything I've read on the subject (reading without much understanding) points to using something like an NTC thermistor as a current inrush limiter, but I don't have the first clue if that's what I really need, much less how to deploy it.  
   
  I'm probably dreaming, but *do you have any knowledge of something I can purchase off-the-shelf, maybe that's made for RC hobbyists, that will limit a LiPo pack's current?*  I'm coming up empty-handed when looking for such a device - which amazes me, considering how useful it would be across many portable applications - not just audio.
   
  Thank you!
   
  Mike


----------



## H22

Quote: 





zilch0md said:


> Hey qusp,
> 
> 
> This goes back a while, but reading this again, I'm very curious about the regulating, dual mono/bipolar supply that is sitting between your 4S LiFePO4 pack and your load.
> ...


 

 yes, go to digikey and type varistor, or MOV, I did a quick search, first part that came up was a 445-2533-1-ND, a small 8 volt 3 amp current limiting device. this one is a surface mount, meaning it has no leads. this makes it a bit trickier to solder to, but it is very small. I am sure one could be found that is through hole (has leads) that would be easier to work with, although bigger.


----------



## qusp

can I ask why you need 3A? i'm using a low noise bipolar regulator, you unlikely need bipolar, or 3A. thermistors will limit current yes, but they are hardly low noise and they do not regulate, they just limit voltage. the amount of voltage drop, like a resistor, will vary with current draw. what is your application? what is the real current limit, there are not many low noise higher current IC regulators


----------



## zilch0md

H22 and qusp,
   
  Thank you for your replies!
   
  OK, here's my application:
   
  I want to power a DACmini CX using a hardcase, 4-cell, 5000mAh LiPo pack (16.8V when fully charged):
   
   

http://www.hobbypartz.com/98p-40c-5000-4s1p-hardcase-direct.html
   
  For H22's benefit, as I can tell from the post I quoted that you're probably already aware of this, qusp...  
   
  RC LiPo batteries are rated at their nominal voltage - assuming 3.7V per cell, but when fully charged, they deliver 4.2V per cell, thus a battery like this one, which has a "4S1P" designation (4 cells in series, with no parallel connections), can deliver 16.8V when fully charged (4.2V x 4 cells), despite being labeled as a 14.8V battery (3.7V x 4 cells.)  
   
  A "5S1P" battery has an 18.5V nominal rating, which sounds attractive, at first consideration, for use with the DACmini CX, given the fact that the DACmini CX can accept any voltage from 9V up to 19V, but a 5-cell LiPo (like the Energizer XP8000 and XP18000) can deliver 21V when fully charged (4.2v x 5 cells), and thus, would need voltage regulation _in addition to_ current limiting.
   
  As you know, these LiPo packs can deliver A LOT OF AMPS.  The C rating of a LiPo battery can be used to calculate the number of Amps it's capable of delivering continuously.  The 5000mAh battery pictured, above, has a 40C rating.  To calculate the number of amps that can be delivered with a continuous load (peak current is typically 50% higher still), just multiply the C rating by the mAh rating and divide by 1000:
   
  40 * 5000 / 1000 = 200 Amps! 
   
   
  The DACmini's switch-mode AC power adapter is rated at 2630 mA.
   
  So... I already see that I'm going to have to teach myself how to solder - even IF I can get my hands on a schematic for a _noise-free _device that can be inserted, inline, between the LiPo pack and the DACmini CX.   In an ideal world, this imaginary device would limit current to 2630 mA (3000 mA would be fine), _without voltage regulation._
   
  There's no need to regulate the voltage of a 4-cell pack.  It can start out at 16.8V (4.2V per cell) and discharge down to 12.0V (3.0V per cell) - at which point, this audible alarm (that I currently use with a different LiPo pack application) would signal that it's time to recharge the pack:  
   
   

http://amzn.com/B003Y6E6IE
   
  The DACmini CX can handle anything from 9V to 19V, so an input that decays from 16.8V to 12V is ideal.  David McKrell, of CEntrance, has assured me that the DACmini's internal power supply takes any voltage that's coming in and converts it to a constant supply voltage at the rails.  Input voltage has no impact on sound quality, as long as there are enough amps and it fits the range 9V to 19V.
   
  Comments?
   
  Thank you, again!
   
  Mike


----------



## chicolom

Buy my Op-Amps!!!
  http://www.head-fi.org/t/633854/opamps-2x-opa602bp-2x-opa827-2x-ada4627-multiple-adapters-capacitors


----------



## zilch0md

Bump
   
  Quote: 





zilch0md said:


> H22 and qusp,
> 
> Thank you for your replies!
> 
> ...


----------



## MSalinas

Hello, I've been browsing this thread and another (Claro Halo thread) for some time to see if I could find some information. Now, what I am most curious about is replacing the Opamps on the Claro Halo. Looking around, I have seen that the AD797BR is one of the most favored opamps. Looking around on ebay, I have found a few for sale. Now, the Claro Halo requires 2 channel (Stereo?) opamps so I would need an adapter for two AD797s to fit in one slot. I've found one on ebay, http://www.ebay.com/itm/270924926938, that appears to be a match. Now, as this is my first few steps into opamp rolling I'm not certain if I have this correct. From initial appearances it looks good. This is why I'm asking you gentleman if you could offer me any guidance or advice in my endeavors?
   
  Furthermore, in case the AD797BR is the wrong choice, what other opamps should I look at? There's so many, it's a bit intimidating. I listen to a mix of genres, ranging from classic rock, alt rock, and rap to electronica music. Any suggestions and tips are very much welcome!


----------



## itshot

Besides tonal differences, can opamps affect separation of vocals and the instruments? If so, are there any in particular that can improve that?


----------



## WiR3D

Quote: 





itshot said:


> Besides tonal differences, can opamps affect separation of vocals and the instruments? If so, are there any in particular that can improve that?


 
  Definitely. AD797, LME49990.


----------



## PurpleAngel

Quote: 





msalinas said:


> Hello, I've been browsing this thread and another (Claro Halo thread) for some time to see if I could find some information. Now, what I am most curious about is replacing the Opamps on the Claro Halo. Looking around, I have seen that the AD797BR is one of the most favored opamps. Looking around on ebay, I have found a few for sale. Now, the Claro Halo requires 2 channel (Stereo?) op-amps so I would need an adapter for two AD797s to fit in one slot. I've found one on ebay, http://www.ebay.com/itm/270924926938, that appears to be a match. Now, as this is my first few steps into op-amp rolling I'm not certain if I have this correct. From initial appearances it looks good. This is why I'm asking you gentleman if you could offer me any guidance or advice in my endeavors?
> 
> Furthermore, in case the AD797BR is the wrong choice, what other opamps should I look at? There's so many, it's a bit intimidating. I listen to a mix of genres, ranging from classic rock, alt rock, and rap to electronica music. Any suggestions and tips are very much welcome!


 
  This is were I got my pre-soldered AD797BRs from, I would say to replace all three(?) of the stock op-amps (keeps them all matching).
  http://www.ebay.com/itm/mod-1x-AD797BR-Dual-Mono-Op-amp-module-ultralow-noise-replace-dual-op-/261100530695?pt=LH_DefaultDomain_0&hash=item3ccacdec07


----------



## FritzS

OP rolling .... I am a little bit confuse, many studio equipment facturers use the old 5532/5534 OPA's still again


----------



## itshot

purpleangel said:


> This is were I got my pre-soldered AD797BRs from, I would say to replace all three(?) of the stock op-amps (keeps them all matching).
> http://www.ebay.com/itm/mod-1x-AD797BR-Dual-Mono-Op-amp-module-ultralow-noise-replace-dual-op-/261100530695?pt=LH_DefaultDomain_0&hash=item3ccacdec07




Could you plug that particular item into an m-stage?


----------



## kiteki

FritzS do you mean you're confused why new studio equipment is still using the NE5532 / 5534?
   
  It could be a lack of interest since they are more focused on expensive microphones, ADC, equalizers, software etc., and it's pretty difficult to 'hear' op-amps in the actual music, via playback equipment! 
   
  So, if they can't hear or sense the difference between NE5532 and AD847 or whatever in the recording chain, via playback, then I imagine they're not in a rush to use the AD847.
   
  I have a feeling the higher-end studio equipment really does use the more sophisticated chips like AD797 and MUSES8920 though, if you look at how much they spend on microphones, speakers, room acoustics etc. then if they have a clue... xx top-end IC's are complete pocket change.
   
   
  Another perspective is for example my latest amplifier purchase used AD8620 on the line-in, LME49720 at the power supply, and NE5532 as the headphone driver!, this is called an 'audiophile' amplifier. 
   
  While the NE5532 is not the ultimate in resolution or transparency it's still pretty high-end sounding and has a favourable tone / character / quality to some users.
   
  So either it just has a nice colour in it, or it's a thin woven mask on so much of 80's and 90's music that when people hear it it's naturally evocative like an emotional reflex.
   
  I wouldn't personally use it in any studio eqiupment though unless the IC's have to cost 50 cents.  If the aim is natural, high-rez and transparent that's what IC's like the MUSES8920 are designed for.


----------



## SpudHarris

AD847?? Why don't I have these??
   
  Are they good?


----------



## qusp

spudharris said:


> AD847?? Why don't I have these??
> 
> Are they good?




nothing really special about them mate, they are a low power video opamp, thus it does have pretty high slewrate, but that doesnt always make it an easy dropin replacement for audio. its current feedback video slinging brethren such as AD811 are superior video opamps when used for audio, but these are not dropin either, due to being current feedback (847 is voltage FB afaik). basically theres nothing that sets it apart from others you already have. the MUSE is a bit lame if you ask me as well.



			
				fritz said:
			
		

> OP rolling .... I am a little bit confuse, many studio equipment facturers use the old 5532/5534 OPA's still again




yes they do, because they are cheap, well performing and very well known/modeled. this means their simulators are able to model the performance of the circuit using these chips quite accurately because the models are very accurate, that cannot be said for many others.


----------



## qusp

zilch0md: sorry I didnt reply to the above mate, theres a significant amount of time involved in a proper reply for that that covers a lot of research I did over the last 2 years and to be honest I not only dont realy have the time, but it also involves research involved in a possible product development. I wouldnt use that alarm though, it will not be designed for audio ie. it will not have been designed wrt the amount of noise it spills back into the power


----------



## SpudHarris

Thanks for the feedback Jeremy, appreciated mate. I'm rolling with the Fi-quest again, man I forgot what a great amp this is. I'm using AD797BRZ's at the moment with 5 stacked BUF634AU's for each channel. It powers my HE-6 better than anything else I have, desktop or otherwise. You still using yours?


----------



## zilch0md

Quote: 





qusp said:


> zilch0md: sorry I didnt reply to the above mate, theres a significant amount of time involved in a proper reply for that that covers a lot of research I did over the last 2 years and to be honest I not only dont realy have the time, but it also involves research involved in a possible product development. I wouldnt use that alarm though, it will not be designed for audio ie. it will not have been designed wrt the amount of noise it spills back into the power


 
   
  Understood.  Thanks for getting back to me!
   
  Mike


----------



## kiteki

qusp said:


> the MUSE is a bit lame if you ask me as well.


 
   
  Ask Esoteric. =)
   
  I think you mean you think the specs are a bit lame for your liking, and / or the pricing of the MUSES01 / MUSES02,... or have you speculated it's some kind of JRC4556 die plus marketing?
   
  I think at least we can agree that studio equipment today still using NE5532, or statements that that chip is at or beyond the threshold of all human perception is certainly 'lamer'. =]
   
  I had the desire to defend NE5532 for a moment but whatever it's not high-end and it's coloured.
   
  I recall you hating on NOS sound a few dozen pages back, just thought I'd mention in passing I can't extract much joy out of my NOS DAC's as of yet.
   
   
   


fritzs said:


> kiteki said:
> 
> 
> > / however right now I'm preferring the more pristine unfettered highs of the AD823!
> ...


 
   
  Actually today I finally tried the LME49720, in the place of AD823 and I like it!!  I don't know how to put it in words but the AD823 was glassy and rivetting while the LME49720 just seems slighty more airy and natural like the smell of a forest. =)
   
  Later I put AD823 where LME49720 used to be and now the hiss and RFI in this amp is very close to zero.  How could a company even release an amp with so much hiss and RFI if the solution was just using the 'right' op-amp?!  I fixed the hiss / RFI and don't have a clue!
   
  I wish someone could explain how all of this works in plain speak.  Like showing an exploded view of the die to us, how everything works at low level within the die, how they improved on that design and why we perceive the IC's as sounding different, even within X versus Y high performance IC's.
   
  Not just "well the high capacitance loads and ceramic decoupling into thermal value parasitics no one can  hear under 0.01% P.S. the LME49990 is cleaner sounding than OPA627 caveat: if you're an EE.".


----------



## zilch0md

Hi kiteki,
  Quote: 





kiteki said:


> [snip]
> 
> Actually today I finally tried the LME49720, in the place of AD823 and I like it!!  I don't know how to put it in words but the AD823 was glassy and rivetting while...* *
> 
> ...


 
  That has to be one of the most poetic choice of words I've ever seen for describing the sonic characteristics of an audio component - but I get it!  
	

	
	
		
		

		
			




   
  The LME49990s in my iBasso PB2 deliver a similar neutral but open and organic quality relative to AD797s.
   
  Mike


----------



## qusp

umm just calling their company esoteric says it all for me. its a ridiculously overpriced, underspecced part in an outdated package that just happens to use a copper leadframe (worth an extra 40 bucks dont you think?), which will be plugged into a brass dip socket.... its outgunned by opamps designed nearly 20 years ago, but it suits esoteric because they can say its an opamp designed for audio... whatever the hell that means. most 'audio spec' parts are rejects that couldnt make the cut for more demanding industrial/scientific applications.

just for example, I know they supply a ready made cop-out for this by saying it gives quality that cannot be measured, but

vs the $5 lme49990

3 x higher noise (minimum, they dont specify at what frequency they measure 4.5nV/Hz, could be up to 5x higher) actually it is closer to 5x looking at the graphs
3 x higher input bias current
4x lower slewrate, you dont want stupid slewrate for audio, but 5v/uS is pretty low
100x higher THD

etc etc, now the lme is a great chip, but not known for its low input bias current, something like the opa827 totally pwns the muse in this regard. sorry but having copper leadframe doesnt make up for it, that and the fact they only come in duals... forget it, its marketing. as ive said before, if I want to build for musicality, i'll build a discrete opamp.


there was nothing to defend about my comments above, for what they are the 5532 are a good chip, but the reason they are used so often is because its a known quantity, bulletproof, pretty stable and cheap.

as for NOS... hmm you know my feelings on that matter



spudharris said:


> Thanks for the feedback Jeremy, appreciated mate. I'm rolling with the Fi-quest again, man I forgot what a great amp this is. I'm using AD797BRZ's at the moment with 5 stacked BUF634AU's for each channel. It powers my HE-6 better than anything else I have, desktop or otherwise. You still using yours?




Hey Nigel, no worries, i'm sure youve got better itches to scratch mate  nothing wrong with it, its been used fairly successfully in dac IV stages because of having decent speed, but nothing really unique about it either. yeah the FiQ is a great amp, not getting much airtime with me though, been meaning to send mine back for an update for ages but never get around to it. 

Nigel, this is what i'm using for transportable these days. zilch0md will appreciate the chunky battery that takes up about half the case volume


----------



## WiR3D

Quote: 





kiteki said:


> Actually today I finally tried the LME49720, in the place of AD823 and I like it!!  I don't know how to put it in words but the AD823 was glassy and rivetting while the LME49720 just seems slighty more airy and natural like the smell of a forest. =)
> 
> Later I put AD823 where LME49720 used to be and now the hiss and RFI in this amp is very close to zero.  How could a company even release an amp with so much hiss and RFI if the solution was just using the 'right' op-amp?!  I fixed the hiss / RFI and don't have a clue!


 
  I dunno about the LME49720, AFAIK even TI admitted its got issues, in the bass regions. Its definitely the consensus over in the STX thread. But it does have one of the best if not the best soundstages. 
   
  BTW the LME49860 is just a higher voltage spec variant if your interested. I also have 2xLME49710HA metal cap on pcb - not bad, but the AD797 and the THS4032 clobber it in everything with the STX anyway.


----------



## SpudHarris

Jeremy, that looks mental mate, absolutely mental! Looks like a beast. Available soon??


----------



## qusp

yeah its a bit mental like its owner... no not available soon, something yes and probably not really that soon (depends on your definition) but not this exactly


----------



## SpudHarris

Well, remember your old pal over in blighty when you need someone with golden ears to test stuff!


----------



## zilch0md

Quote: 





qusp said:


> [snip]





> Nigel, this is what i'm using for transportable these days. zilch0md will appreciate the chunky battery that takes up about half the case volume


 
   
  That's beautiful!    Transportable and then some!
   
  Mike


----------



## kiteki

qusp said:


> they can say its an opamp designed for audio... whatever the hell that means. most 'audio spec' parts are rejects that couldnt make the cut for more demanding industrial/scientific applications.


 
   
  Any examples of that?
   
   


qusp said:


> MUSES vs the $5 lme49990
> 
> 3 x higher noise (minimum, they dont specify at what frequency they measure 4.5nV/Hz, could be up to 5x higher) actually it is closer to 5x looking at the graphs
> 3 x higher input bias current
> ...


 
   
  The http://semicon.njr.co.jp/eng/product/opamp/NJM4580.html has 0.0005% THD, the MUSES chips are higher right?  I see people repeat very often we can't hear under 0.01%, so what is your take on that?  I'm just curious.
   
  That does appear low, here is a discussion on the 2V/uS slew rate in the OPA111 just fyi - http://www.head-fi.org/t/52255/anyone-tried-the-opa-2111/15#post_608042
   
  I don't think it's marketing, that seems unlikely.  The retailer prices are too high but that's the same story for the OPA627 and balanced-armature driver units as well which cost 5 times more than they're supposed to.  I can get BA parts cheaper by breaking finished IEM's than I can from Mouser.


----------



## kiteki

spudharris said:


>


 
   


			
				zilch0md said:
			
		

> /img/forum/go_quote.gif


 
   
   
  Spud and Zilch, if I remember correctly you both currently have (or have had) the iBasso Warbler and the iBasso Pelican.
   
  Can you offer some honest thoughts on how they compare, and if balanced actually has any improvement apart from stereo seperation?  To me I'm wonder if that's worth the hassle?
   
  I noticed the Pelican has 2500mW output power, does that mean if I adjust the volume in my pocket by accident I could break an IEM?
   
  Thanks in advance if you feel like answering. =)


----------



## zilch0md

Hi keteki,
   
  I've never owned nor heard the Warbler, but I still have the iBasso PB2 Pelican.
   
  If you are using IEMs, there's really no need to get the PB2, in my opinion.  They have jumpers inside that allow you to select one of three gain settings, so you can select low gain for IEMs, but even then, I think it's more power than you need - even if the volume is not excessive.
   
  Nigel - do you have any experience with the Warbler?
   
  Mike


----------



## SpudHarris

The Warbler is the P4 and is single ended. That said, it is an amazing amp especially for the price. It's one of my few keepers....
   
  Kiteki, you are spot on when you say about stereo separation being improved by the balanced Pelican (PB-2) but it's not just that. It just seems a little cleaner and tighter (if that's the correct terminology?). Especially with full sized phones like LCD-2..... Going completely balanced (DB-2 > PB-2) offers very little improvement over single ended input into the PB-2. I have A-B'd so many times and each time I convince myself that totally balanced is better but if I am totally honest it is likely placebo.


----------



## kiteki

Thanks, can you explain why you want to keep the P4 when you already have the PB2?  In non-balanced mode are there differences?  I noticed the P4 says something about 3ch/4ch?


----------



## SpudHarris

They just give something different even with the same opamps, In 4 channel mode the P4 is a very exiting amp to listen to, the PB-2 is probably a more realistic sounding amp and one I transport for vacations etc with a set of balanced cans (D7000 usually). The P4 is a nice form to strap to a classic for an involving on the go listen but not one I use for critical istening. With the right chipset you probably could tune it for any application I just choose to have the two amps for separate uses.
   
  Hope that helps.


----------



## zilch0md

Nigel,
   
  Quote: 





spudharris said:


> [snip]
> 
> *Going completely balanced (DB-2 > PB-2) offers very little improvement over single ended input into the PB-2.   I have A-B'd so many times and each time I convince myself that totally balanced is better but if I am totally honest it is likely placebo.*


 
   
  A voice of reason speaks!   Thank you for helping to debunk the myth.  You're singing my song, here.
   
  I've blind tested this with the help of a friend, having volume-matched single-ended output from the iBasso DB2 DAC vs. balanced output, using the JL Audio SPL Meter iPhone app with a lapel mic sandwiched between the ear pads of my LCD-2 to deliver 85.0 dB with both of them.  Then, using balanced output to my LCD-2 while playing a white noise WAV file, I've beaten this to death, but can't hear any difference.   
   
  I've written this elsewhere, but I believe the greatest benefit to be had by using a balanced output DAC to drive a balanced amp is for noise reduction with long cable runs (between DAC and amp).  
   
  Thanks!
   
  Mike


----------



## WiR3D

Quote: 





zilch0md said:


> Nigel,
> 
> 
> A voice of reason speaks!   Thank you for helping to debunk the myth.  You're singing my song, here.
> ...


 
  what about using balanced the way Kingwa does? Which AFAIK is for better volume control among other things? (I can't find the article I read that explained why he went balanced)


----------



## zilch0md

Hi WiR3D,
   
  Quote: 





wir3d said:


> what about using balanced the way Kingwa does? Which AFAIK is for better volume control among other things? (I can't find the article I read that explained why he went balanced)


 
   
  Interesting.  I'm not familiar with Kingwa's article, but if I'm interpreting your question correctly, the volume control would offer a greater range of control when using the balanced output of a dual DAC rather than using the singled-ended output (using only half of the dual DAC).  The iBasso DB2 balanced dual Wolfson DAC outputs 2.0 Vrms, for example, with balanced output relative to the single-ended output (1.0 Vrms) - because you're using the whole DAC instead of only half the DAC.  
   
  Using the amp's volume control to match SPLs at the headphones, you would indeed have less headroom when running single-ended from such a DAC, so single-ended is compromising if you have power-hungry headphones that truly need the headroom offered when using the whole DAC instead of half of the DAC (2.0 Vrms instead of 1.0 Vrms).  With more efficient headphones an amp might be able to offer sufficient headroom whether it's fed with 2.0 Vrms or 1.0 Vrms - in which case, the amp's volume control could be set lower with balanced out from the DAC vs. single-ended output, offering a greater range of control, all else being equal.
   
  BUT:  There are plenty of single-ended DACs out there that can output 2.0 Vrms.  You don't need to buy a balanced output DAC to get more than 1.0 Vrms into your amp.
   
  Mike


----------



## smengy1

Hello,
     I have a Auzentech X-Meridien 2g.  I made a dual lme49710ha module for it.  I complained on the board that the sound from them
  while detailed,  was way too harsh.   So I ordered a OPA2111AM and a lme49720ha. 
   
  Well the opa2111am,  I don't know if I fried it while soldering but one channel was weak.   As a matter of fact,
  the good channel was weak as well.  So bah no real opinion of it sonically.
   
  The lme49720 was great!!!  While it lasted.  The bass was booming!  The mids and Highs were juicy!!
  I could blissfully punch the equalizer levels all the way up in the high band and the hissiness was not
  bad at all.  It behaved and sounded like the old automobile equalizer I used to use to amp up
  my Panasonic Platinum box that had a tape machine hooked to it.  
   
  But after like 40 minutes as I was playing with the bass bands on equalizer,  and switching between
  44, 48, 96 and the 19? sampling,  the left channel dropped like 40 decibels and started popping.
   
  I took it out and put it back, still popped and was nearly dead with low output.
   
  After awhile,  before I was going to throw it out,  i did a Fonzie and threw it on the floor,   denting the
  99's metal cap.   Put it back in and it worked!!  Though after listening to it, it was now just as harsh as
  the dual lme49710's!!!   
   
  I guess one of my solder joints was bad?  I dunno.  Guess I'll try again.
  It was really nice and warm sounding with lots of bass!!!   And the mids were smooth and juicy!!
  If I can get a lme49720 to not **** out on me, it is definitely my choice for playback!!!
   
  For mastering I am going to use the 710's because they pull up the clicks and pops in the vinyl and make
  it easier for me to hear it and correct it with my Diamond Cut Audio.
   
  The Auzentech is doing an incredible job of capturing the Audio off of my LP records.  I am floored at the quality.
  I have to say I barely hear a difference from the recording and original.   Diamond cut does not use Asio4all, but
  when I use that it is very close to a perfect capture of the recording.  Asio in that player with the alien head(sorry cant remember name)
  amps and cleans it up to the level of the raw input of the turntable.  There is a very slight sound stage compression,  but thats fine
  with me as the original recording is too lively sounding.  The very slight negative attenuation actually makes it sound better!!!


----------



## qusp

there are many reasons to go balanced, its not a magic bullet, but its not a myth. using the LCD2 and a fairly average balanced dac circuit isnt the best conditions, LCD2 are a piss easy load, one of the easiest headphones to drive of any type, so your main improvement will be from the dac, so i'm not surprised there was little difference. without a balanced source its pointless for all but a very few very inefficient headphones


----------



## zilch0md

I hear you qusp and I respect your expertise, greatly.
   
  Indeed, my testing was done with the LCD-2 and a the iBasso DB2 - which I returned under iBasso's generous no questions asked 10-day trial guarantee, so I acknowledge that I was not impressed with the DB2 and thus, in my opinion, the DB2 fits your description of "a fairly average balanced dac circuit."
   
  That said, I'm left wanting to understand your convictions.  Please elaborate.  What precisely does an excellent balanced DAC do for a balanced amp that an excellent single-ended DAC does not - and why?
   
  Eager to learn,
   
  Mike


----------



## qqexpress

Hey guys I own the Asus Xonar Essence One and am interested in opamps for it, can you guys recommend a good combination for the E1 > Sennheiser HD800 + Denon D7000?


----------



## kiteki

wtfwtfwtfwtwfwtwwfwffffffffffffffffffffff I just put LT1363 in ... hello?  This is the most surprising chip ever.
   
   
  ...and I just spent over $150 on To-99's ahhhhhhhhhhhhh


----------



## leeperry

LT1363 is an amazing opamp, we thought you knew ^^


----------



## kiteki

I've seriously never heard of it apart from someone recommending using it as ground, with OPA627 in stereo L/R, I couldn't hear a jack-muffin......
   
  Then I put LT1363 in L/R with AD797 as buffer (not supposed to but all the other buffers sound like ****) and then proceeded to wtfwtfwtfwtfwtfwtfwtf IT'S NOT HUMAN.


----------



## leeperry

Personally I love how its very high speed allows it to kinda recreate the room acoustics and it's like you can hear the room reverb, vocals also sound surreal. Of course, it's not perfect....I don't think any opamp apart from AD797B really is, especially when rolled blindly. MadMax finds it too colored IIRC.


----------



## kiteki

Are there any other chips like this one?  It makes OPA1612 sound like a joke.  I wasn't even expecting anything...... I should write a story about this chip.
   
   
  The weird part is, I'm using my NOS DAC tonight, first time in a long time, I never knew NOS could sound so detailed, it's bizarre.


----------



## leeperry

I guess my top 5 would be AD797B, OPA602BP, OPA1611, LT1363 and LT1028AC in the right order. But it all depends on the surrounding circuit as these can't really be rolled blindly or they will oscillate like crazy.


----------



## kiteki

Ok, I just ordered 4x OPA602BP, never heard of it, ain't gonna read nothin', let's see if my thoughts on it coincide. =D
   
  The LT, you said surreal vocals, is it kinda like chalk in a freezer?  In terms of note, not tone, still silky.


----------



## Mad Max

1363 sounds yucky and dull in my gear, ugh!
Crazy amounts of detail, though. Runs hotter than a frying pan, LOL! Definitely doesn't belong in my stuff.

Ha, my top opamps are OPA827, ADA4627-1B, AD797B, OPA602, OPA1611, and OPA209, in that order of preference. All pimped out with ceramics and MKP1837 or MKP416 caps on the psu pins.


----------



## DingoSmuggler

Quote: 





mad max said:


> 1363 sounds yucky and dull in my gear, ugh!
> Crazy amounts of detail, though. Runs hotter than a frying pan, LOL! Definitely doesn't belong in my stuff.
> Ha, my top opamps are OPA827, ADA4627-1B, AD797B, OPA602, OPA1611, and OPA209, in that order of preference. All pimped out with ceramics and MKP1837 or MKP416 caps on the psu pins.


 
  hot = oscillation


----------



## Mad Max

dingosmuggler said:


> hot = oscillation




Thanks, I would have never guessed. Have you played with ADA4610?


----------



## kiteki

Well, I've had my amplifier on for over 10 hours at max volume (burn-in experiment), I just opened it up (yeah, I screwed it shut, that says somethin') and touched the chips... the LT's are like... a little under skin temperature, less warm than the skin on my neck, heh, I don't think there's any oscillation here. =]
   
  It's the kind of intrinsic detail I've always ached for, no expectation bias since I wasn't expecting jack from them, lol.
   
  No op-amp sounds perfect, unless you've been persuaded into reading specs, essays and dScopes, and delusionary thereafter.  Music isn't supposed to sound flat and neutral, OPA1611 with a STAX SR-009 and crystal cables is a joke...
   
  "huh... I take it on and off... it sounds like... nothing!!  It's invisible!!  I can't hear any difference between this and... fresh air!!......  now all I need is a cloaking device and I won't even _see_ it! ><"
   
   
  Music is supposed to sound hyper-extended, hyper-detailed, with more distinct layering, closer intimacy at different frequencies, revealing in secret nuances within the music, with an intact, uplifting and unnatural tonal colour.
   
  A karaoke room isn't "reference / flat" sound, it enhances the singers voice (just like studios), recording uses all kinds of microphones with tailored FR, to 'zoom in' on the right content.  Technology and spikes in your transducers will zoom in further for heightened perceptivity and impact.
   
   
  As such, op-amps are all different flavours of soft-drink (except OPA627 which is tears in a vanilla milkshake), it's just most of them taste like Diet-Coke from a tin can, AD797 like Tonic Water, and LT1363 like Coke from a glass with ice and lemon.


----------



## SpudHarris

The LT1363 never stayed too long in my gear as I always liked others more. My favourite amp with rolling capability is the Fi-Quest and I have yet to find anything better sounding than OPA1641's in this. I will swap them out tonight and give the 1363's a good listen, I know they were always one of Leeperry's favourites but I just never got it. Maybe my ears have matured now, we'll see....
   
  My Favourites are OPA1641 / AD797B / OPA602BP + CM / ADA4637-1BRZ / OPA827 in that order.


----------



## kiteki

Thanks for sharing SpudHarris, it was your picture of the LT1363 in the ground channel in the Warbler which made me buy two of them in the first place, so I am eternally grateful.


----------



## SpudHarris

Glad to help 

Can't remember when I last used them in ground. I prefer the ISL5002 in the P4....

The LT1363's are in my Fi-Quest and I will give them a good listen in L/R tonight, I've had a quick listen but will report back tomorrow.

I've said this before but I am not a massive fan of LT chips in L/R. Nearest I got was LT1122


----------



## kiteki

If you try them in the Warbler, use them x2 in L/R, a quality buffer x2, bypass virtual, bypass ground.


----------



## SpudHarris

Will give it a try. Results in Fi-Quest are good but not a patch on OPA1641....

Will get the P4 out tomorrow and try.


----------



## zilch0md

Oh Nigel!   Are you still rolling opamps?    
   





   
  I was doing great until I cracked open my PB2 a couple of weeks ago, for the first time in about three months!  
   
  It wasn't long before I got swallowed up in a downward spiral there for a couple of days - I'd call it a lost weekend, for sure - but when I started to twitch all over and get convulsions, I managed to pull myself together and call the op-amp rolling obsession prevention hotline.  They talked me down.  Good people, those volunteers.   
   
  The next day, I flushed all my spares down the toilet. You should think about it Nigel - seriously.
   
  Your friend,
   
  Mike


----------



## kiteki

That makes me feel better the OPA627SM's I bought are not that costly in alcohol terms.


----------



## Mad Max

zilch0md said:


> Oh Nigel!   Are you still rolling opamps?
> 
> 
> 
> ...




I'll sell you some of my spares at bargain prices. 
:veryevil:


----------



## SpudHarris

Quote: 





zilch0md said:


> Oh Nigel!   Are you still rolling opamps?
> 
> 
> 
> ...


 
   
  LOL
   
  Mike, I'm afraid I fell off the wagon last night but only for the LT1363 trial.
   
  I listened for 3 hours and have to say they sound quite nice in my Fi-Quest but they are not the holy grail. Will try in the P4 tonight just in case.... I've been listening exclusively with my HE-6 of late and I think I've been a bit spoiled. I use a Topping TP60 speaker amp to feed them and boy does the extra power make a difference, none of my other amps/phones compare with the HE-6/Topping combo.
   
  Will try the P4 and Fi-Quest with easier to drive phones for a fair comparison.


----------



## kiteki

The HE-6 is quite different than the tiny Vsonic and TWFK IEM's I used to listen to the LT1363, just sayin'...
   
   
  It doesn't deliver the power of a speaker amp, or the transparency of an OPA16XX, but what it does do for me, it does extremely well.


----------



## AnAnalogSpirit

.


----------



## George_63

Could anyone tell me if 3.9k resistors are ok for an A class biasing of OPA2227? What resistor value would be the optimal for an operating voltage of 15V?
  Thanks...


----------



## Avro_Arrow

Resistors are not good for class A biasing...A CCS is the preferred method.


----------



## jcx

resistors can be OK depending - like everything in engineering
   
  if you have high supply V re the actual headphone drive requirement simple R loading can be fine
   
  also depends on whether you're trying for full Class A directly driving the headphone or if you're talking about a op amp + buffer circuit
   
  simple R do load the op amp output more, reduce small signal gain - but if the added R are a much higher value than the headphone Z, within op amp load spec, then their added load may not really matter
   
  if you need greater efficiency, are going to swing nearly to the amp Vsupply limits then active ccs is better - and led/bjt or bjt "ring of two" waste much less V than the (locally to head-fi) faddish jfet ccs


----------



## kiteki

A qiuck question... are there any inherent flaws in using a chip like AD797 as a buffer?  If it sounds good, y not?


----------



## qusp

kiteki said:


> A qiuck question... are there any inherent flaws in using a chip like AD797 as a buffer?  If it sounds good, y not?




yes, as ive covered here a number of times, its really not what I would call unity gain stable. they are stretching the truth in the datasheet, it needs a very well laid out and well executed PCB to make this work properly, its very prone to oscillation otherwise and not exactly happy driving capacitive loads (headphones), or low impedance loads*

basically it requires a heap of boxes ticked that are unlikely to be present on a PCB not designed for it

*its not exactly high in current, though higher than many, 30mA isnt exactly what I would expect from a buffer. For example the BUF634 or LME49600/10 put out 250mA and are truly unity gain stable.


----------



## kiteki

Ah I see thanks.  I think BUF634 sounds like rubbish, so how about OPA627 what if I use that as a buffer what happens then?


----------



## SpudHarris

Have you tried HA5002? it's my favourite buffer of all...


----------



## qusp

kiteki said:


> Ah I see thanks.  I think BUF634 sounds like rubbish, so how about OPA627 what if I use that as a buffer what happens then?




haha, I think its more likely the way you (or whatever ebay dac it was) used it sounded rubbish, to say the Jung diamond buffer itself (the discrete circuit both BUF634 and LME49600/10 are based on) sounds rubbish, is quite frankly.... rubbish.

opa627 is unity gain stable, but again current limited for true buffer applications. it will work with a good amount of headphones though, as many dont need much current. very low impedance headphones/IEMs will perhaps present some difficulties if driving direct with opa627

Spud: nah I never bothered with the HA500X, I like the LME49610 because of higher voltage and good current/power capability if used on a suitable PCB and if I want more, or something really different I build something discrete, since I now have a pretty large parts bin, with many and varied mosfets, jfets, transistors, passives etc I can build most things I need on the spot.

BTW soz mate I just saw the message you sent me last week, did you sort that out or should I take another look? its been a while since I used my amp so i'll have to dig it out to check for you.


----------



## kiteki

I tried ordering it, ceramic and all, then they cancelled my order and said they couldn't find it.  Right now there's only one on ebay, selling for $25 a piece, seems like way too much hassle.
   
  Likewise, I placed an order for LT1010, then noticed the seller had too much negative feedback... cancelled it.
   
  Can I convert an LME49600 into DIP form by twisting it around?


----------



## kiteki

> Originally Posted  *qusp* /img/forum/go_quote.gif
> 
> btw soz m8


 
   
  No worries m8, I'll yuse da oppah627 as a buf den, since it shud hav enuf current 4 da IEM applekayshuns no?


----------



## qusp

kiteki said:


> I tried ordering it, ceramic and all, then they cancelled my order and said they couldn't find it.  Right now there's only one on ebay, selling for $25 a piece, seems like way too much hassle.
> 
> Likewise, I placed an order for LT1010, then noticed the seller had too much negative feedback... cancelled it.
> 
> Can I convert an LME49600 into DIP form by twisting it around?




no, you cannot, it uses PCB for heatsinking and the tab is live negative voltage. people have done it with the use of isolated heatsinks, but personally I think its a silly idea and you should just use BUF634



kiteki said:


> No worries m8, I'll yuse da oppah627 as a buf den, since it shud hav enuf current 4 da IEM applekayshuns no?




I wasnt talking to you, since it still appears you havent read anything about ohms law, I guess you dont know that IEMs are *the least likely* to cope with it. you'de have better luck driving HD600 or even DT880/600 than many IEMs. high impedance = low current, low impedance = high current

how in hell people can mod stuff for years and still not read up on Ohms law I have no idea


----------



## SpudHarris

[COLOR=FF00AA][/COLOR]





qusp said:


> BTW soz mate I just saw the message you sent me last week, did you sort that out or should I take another look? its been a while since I used my amp so i'll have to dig it out to check for you.




No worries pal, strangely enough I got a mail the following day off Ryuzoh asking me to review a new DAC and he says the Fi-q works best via mains with switch in position 3. I still love mine but of late most of my listening is with HE-6 via a Topping TP60 speaker amp and In my limited experience it's the best I've ever heard..... Thanks anyway bud.


----------



## SpudHarris

Double post - Sorry


----------



## kiteki

qusp said:


> high impedance = low current, low impedance = high current


 
   
  So a DT770 / 600 ohm is low current, and a sensitive 16 ohm IEM is high current?  I don't get it, but thanks anyway.


----------



## fmlfml

I used to have a Audio GD OPA Earth,
  it sounds quite good and you might want to try it out!


----------



## Mad Max

Well, at the very least those Audio-gd opamps are slow enough to be dumped into most circuits without them overheating, and they already have a wire for grounded psu bypassing.
  The stock MKT bypass caps don't quite do them justice, in my opinion.  You have to replace them with Mundorf film cap(s) or Russian PIO K42-Y2 cap(s).  I've gotten major improvement in sound with ceramic and tantalum caps, never tried the Mundorfs or PIOs.  I still have Sun, my favorite of the three for its energetic and forward presentation.
  I dislike how incredibly bulky they are compared to chip opamps, and they can't sound as good either.
   
  Now I remember that I never got around to trying out 827, 4627, and 797 with those Russian capacitors.


----------



## kiteki

qusp said:


> to say the Jung diamond buffer itself (the discrete circuit both BUF634 and LME49600/10 are based on) sounds rubbish, is quite frankly.... rubbish.


 
   
  I'm not familiar with diamond buffers but the BUF634 isn't transparent sounding.  From what I've seen around h-f and diyaudio I'm not alone in that opinion.  I'm using it in an iBasso amp, not an "ebay DAC", not that there is anything wrong with ebay DAC's!, is there?
   
   


qusp said:


> you'de have better luck driving HD600 or even DT880/600 than many IEMs.


 
   
  Can you expand on this?  So let's say a full-size headphone and IEM of equal impeance, let's say 50 ohm, doesn't the full-size ideally need quite a lot more mA?


----------



## kiteki

mad max said:


> I still have Sun, my favorite of the three for its energetic and forward presentation.


 
   
  Have you tried any other discretes than from Audio-gd?  I know qusp mentioned that the AD797 inventor is releasing a DIY discrete.


----------



## Mad Max

Quote: 





kiteki said:


> Have you tried any other discretes than from Audio-gd?  I know qusp mentioned that the AD797 inventor is releasing a DIY discrete.


 
   
  Yes, when I said that Sun is my favorite, I did mean to imply that I tried Earth and Moon as well.  These three plus OPA2134 and LME49710 were the first opamps that I ever rolled.  Earth was my favorite... but then I tried ADA4627-1B and never looked back... and then I began to rediscover my opamp collection with extra psu bypassing, so that is when I revisited the Audio-gd opamps.  I ultimately sold Earth and Moon and kept Sun.

  No matter what I did to Moon, I never liked its weird sound. Versus OPA2134, LME49710, and a few LT and other TI chips, I liked Earth a little better as it sounded more "right".  4627, 797, OPA827, and several other TI and Intersil chips all make Earth sound muddy, overly colored, and unnatural by comparison.  But I compared the latter bunch versus Earth with all of them having extra psu bypassing.  It seems to me that without the extra bypass caps, Earth may smoke those others in sound depending on the circuit.  Well, many of those chips aren't great candidates for blind rolling anyway.  =p
   
  Sun can seem to have a strangely roller-coaster-like FR without upgraded psu bypass caps, really bizarre.
  Oh, then there's the matter of the A-gd opamps having fatiguing treble when they are new and not burnt in.  =/


----------



## kiteki

Now you're actually making me want to buy them!  I only have one discrete op-amp which is made by a different company in Taiwan.


----------



## Mad Max

Sun is fun!


----------



## SurfWax

I have 3 OPA 2107 I received from TI, I have decided against getting the LDI+ and will be getting an Asgard. So no need to keep them. Brand new, unused, still in anti-static bag, just opened it to verify contents.

 Got them for free, will sell them for free. Just pay me for postage and you can have all 3 - I won't split them up because I'd have to get different cases for each. Will ship them in 2-3 weeks, so we can do it then, just wanting to put this out there early so it's all set up and ready to go when the day comes. First response gets them, just PM me!


----------



## kiteki

Hmm I just found this http://www.twistedpearaudio.com/digital/*cod*.aspx
   
   
  The "current-out DAC" which allows for passive / external I/V.
   
   
  Cusp weren't your bashing passive I/V concepts a wihle ago?  This DAC is released by the same company as your Buffalo...............


----------



## qusp

i'm sorry, whats the question?

ANY current out dac allows passive or active IV stages. I V stands for Current (I) to Voltage (V) conversion


----------



## kiteki

I thought you thought current-out / passive I/V designs are inherently flawed, well it seemed that way at the time, I didn't expect to see a passive I/V DAC from Buffalo.
   
  I don't know, I suppose I connected you to Buffalo, and was thinking "qusp = buffalo" and then saw "buffalo = passive I/V", so was interested in your thoughts on that model, I suppose, since you know a lot about DAC's 'n stuff.


----------



## qusp

what in what I just said makes you think i'm FOR passive IV?

you still havent read up on Ohms law have you? 

put resistance in the way of current, it turns into voltage, put resistance in the way of voltage, it turns into current....that conversion can be done passively with a simple resistor, or it can be placed at the output of a current feedback amp, discrete follower/buffer or in the feedback loop of an opamp so that the amp or active device in the active IV stage is driving the resistor to convert to voltage for your amp to amplify. 

this means that the dac can be allowed to drive a very low impedance, not as hard work. its a current source remember, not the voltage source we spoke of before driving headphones, if you want current to stay current, you need to provide a low impedance

passive IV with ES9018 is Dumb, you need a really robust current source to use passive IV, even then i'm not a big fan, but with ESS you lose performance significantly, could be as much as 20dB THD lost. the ESS is a pretty wimpy current source, not low current, but not high impedance, an ideal current source has infinite impedance, es9018/12 is only 195ohms output impedance in stereo mode, so you need a REALLY low impedance

some companies still persist in using passive IV with ess, not many though

the COD is just a current out dac (PCM1794A) wit power supply, its a VERY rudimentary design, the dac is kinda just there, its a current out dac, but the 1794A has a higher (but still not that high) output impedance, so will work with passive IV better than es9018, that being said the ess will still win out, but with a lot of wasted potential.


----------



## kiteki

I don't know about you, but I'm noticing a pattern in high-end audio that it's taking the path of either one of these two...
   
  - NOS / passive I/V / PCM1704...
  - 128x oversampling / 192kHz upsampling / OPA16XX / LME49XXX / ES9018...
   
  You and someone else had me fairly convinced that passive I/V is inherently flawed, I'm surprised / confused Buffalo is selling it as well, just like I was surprised the Hifiman HM-901 changed from PCM1704 to ES9018 recently, worlds apart, yet always next to eachother?, lol.


----------



## qusp

why are you surprised? ESS is the name on everyones lips, what makes you think the change was about anything more than that and the fact the DX100 was massively outselling the HM801?



Spoiler:  OT



I dont really agree with dual mono, the ESS is already made of 16 parallel balanced dacs and the power supply topology is already set up for dual mono with one chip, so there is no added separation from using 2 and unless they actually exceed the analogue spec offered by the single chip, which is already a task, then its just using battery. i'll be interested to see what they come up with, but I feel there are other areas that should be taken care of before adding another dac chip; particularly if theyve had to make compromises to make it happen

twisted pear isnt selling passive IV.... they dont sell an IV board that does passive IV; they simply mention its an option so as not to alienate those who like passive IV and as a matter of completeness. passive IV is an option with ANY current output dac.

besides, I do use a buffalo II in my transportable because its compact and easily powered, nothing else in the build is twisted pair and I modified the dac board too, I think it was their last really good design, but my home dacs are ackodacs, i'm not a huge fan of the way the TP design has developed and dont regret jumping ship.

there are some nice voltage dacs too like the AK4399 from AKM, but generally (and with some trouble I might add) you can get higher performance with current out dacs when all your ducks are in a row, while something like the AKM is more easily applied and more robust, perhaps a better choice for some of the BIII builders i've seen and honestly some of the commercial ESS designs ive seen, itts not an easy dac to apply properly and many seem to miss the mark



anyway enough OT


----------



## hoshiyomi

Quote: 





kiteki said:


> So a DT770 / 600 ohm is low current, and a sensitive 16 ohm IEM is high current?  I don't get it, but thanks anyway.


 

 Ahhh just happened to drop in this thread and this is driving me nuts. lol
   
  How about this, 600 Ohms is high impedance so high voltage, 16 Ohms is low impedance so low voltage.
  Voltage being inversely related to current at any given impedance, therefore 600 Ohms is low current and 16 Ohms is high current.
   
  You got 4 Ohms & 8 Ohms speakers don't you?
  Intuitively you wouldn't think these deserve just some low current TL072 right?
   
  --
  a side note, qusp you really have the patience of a superman!


----------



## Soun

Hi everyone, apologies upfront if I may have missed any info anywhere (this is an overwhelming forum).

I'm new to this, and Xmas started slightly early for me as I have just been given a iBasso D12. As well, I was handed a few opamps (I think) and was wondering if these are ok to plug into the D12. I was told they are all duals, meaning I should only plug one in at a time? They all look the same, black with 8 pins and have the following written on them:

UTC UAA2 MC1458BL YA
JR15ABE3 LMC64 82AIN
96A4K9M RC4558P
JC73RA LM 833N

Any insight is greatly appreciated.

Cheers


----------



## zilch0md

Quote: 





soun said:


> Hi everyone, apologies upfront if I may have missed any info anywhere (this is an overwhelming forum).
> I'm new to this, and Xmas started slightly early for me as I have just been given a iBasso D12. As well, I was handed a few opamps (I think) and was wondering if these are ok to plug into the D12. I was told they are all duals, meaning I should only plug one in at a time? They all look the same, black with 8 pins and have the following written on them:





> *UTC UAA2 MC1458BL YA
> JR15ABE3 LMC64 82AIN
> 96A4K9M RC4558P
> JC73RA LM 833N*





> Any insight is greatly appreciated.
> Cheers


 
   
  Hi Soun,
   
  You are very smart to have asked before trying those op-amps!
   
  I'm not nearly as experienced at rolling op-amps as several others on this thread, but I've never heard of any of those, so unless you receive encouragement from someone else, I would say do not plug any of those into your iBasso D12.  
   
  Wait for someone to make a recommendation of what they have tried successfully...
   
  Mike


----------



## jcx

I think a very important idea for anyone new to this thread is that the thread contents may in fact not be "valuable information" - but are rather mostly "noise" - are based on dubious "socailly constructed" ideas
   
  several conceptual errors collide here - naive "just listen" "subjective evaluation" and ignorance of op amp qualification by application circuit differences, not recognizing different performance demands in preamps, DAC I/V, filters, buffers, headphone driving
   
   
  naive "just listen" "subjective evaluation" - is the mode throughout the audiophile world - overwhelmingly represented in the press, marketing - but ignores real human limitations, known perceptual psychology - try learning some of the science
   
   
  and there are hundreds of op amps made for the very reason that they have different mixes of noise, frequency response, gain, slew rate, output current... each op amp's mix of specs may suit different circuit applications - since nothing practical can be built with "the best" specs for every application
   
  but the overwhelming majority of "recommendations" here ignore/don't mention the circuit application, or even the power supply Voltages - and even within a category of a specific audio circuit type the engineer can make differing decisions on circuit details that affect op amp choice
   
   
  obviously the idea of op amp rolling is compelling, people like playing - but most of the posts here are technically, psychoacoustically without value - a few could be harmful to your equipment
   
   
  note to moderators - and committed kool aid drinkers (or "committed subjectivists") - I only point this out at very infrequent intervals - thousands of posts go by between "critical" posts - and I am addressing newbies - such as have recently posted - they deserve pointers to alternative opinions, information on the scientific, engineering basis of their hobby - to decide for themselves where to spend their time, money


----------



## zilch0md

Please give us said pointers.


----------



## Mad Max

Quote: 





soun said:


> Hi everyone, apologies upfront if I may have missed any info anywhere (this is an overwhelming forum).
> I'm new to this, and Xmas started slightly early for me as I have just been given a iBasso D12. As well, I was handed a few opamps (I think) and was wondering if these are ok to plug into the D12. I was told they are all duals, meaning I should only plug one in at a time? They all look the same, black with 8 pins and have the following written on them:
> UTC UAA2 MC1458BL YA
> JR15ABE3 LMC64 82AIN
> ...


 
   
MC1458
LMC6482
RC4558
LM833
  All are dual-channel opamps indeed.  After inserting one in the right position and orientation, turn on the amp without your headphones plugged in and check and see if the chip gets very hot.  If so, then turn the amp back off and remove it.  Don't bother with those overheating chips, although all of these should work okay since they're all slow opamps.
   
  LM833's datasheet says that it is for preamplification, among other things, so perhaps you should avoid putting that chip in the buffer position just to be safe.
   
  Make sure that you don't put them in backwards or you will damage the opamp and possibly the D12.  Each chip has a notch that indicates which side of the chip that pins 1 and 8 are on.  Or there will be a printed or embossed dot next to pin 1.  Judging by this photo, when you insert an opamp into the D12, pins 1 and 8 should face your left if you are looking at the front of the amp with the headphone output and volume knob.
  Edit: the linked photo shows single-channel opamps in the amp, make sure that you _do not_ insert those dual opamps in the same manner!  I think that the duals go in the middle somehow.  Another D12 user should be able to confirm.


----------



## jcx

Quote: 





> Please give us said pointers.


 
   
  the Sound Science forum was  created as a ghetto to keep discussion of double blind testing, the Science of controlled listening out of "regular" threads on the grounds that it turns into flame wars
   
  so that is now where such discussion lives - you can search for comments on op amp rolling - or create a dedicated thread there for discussion around the topic - but with DBT, ABX, psychoacoustic Science allowed


----------



## Soun

Quote: 





zilch0md said:


> Hi Soun,
> 
> You are very smart to have asked before trying those op-amps!
> 
> ...


 
   
  Cheers zilch0md, the aim was definitely not to fry a new present that I wanted for years.  So yes, definitely asking before doing anything drastic.
   
  Quote: 





mad max said:


> MC1458
> LMC6482
> RC4558
> LM833
> ...


 
   
  Thanks Mad Max, I did come across the same photo, so all good in terms of the chip orientation for when replacing.  Just no sure about if they are suitable at all.  I did read about buffer as well as actual opamp, so the bit about being able to load opamp into buffer is new to me as well, so more reading there I guess.  And lastly was definitely keen to learn more about voltage fitting etc.  So anymore insight on these are welcome.
   
  The D12 came with a rolling kit as is, i.e. a dual opamp, so it has room for fitting it in the middle.  It was a little easier to figure this one out as it's of the same time, i.e. SOIC on DIP 8 converter (did more reading! )
   
  Cheers - Soun


----------



## zilch0md

Hi jcx,
   
  Quote: 





jcx said:


> I think a very important idea for anyone new to this thread is that the thread contents may in fact not be "valuable information" - but are rather mostly "noise" - are based on dubious "socailly constructed" ideas
> 
> several conceptual errors collide here - naive "just listen" "subjective evaluation" and ignorance of op amp qualification by application circuit differences, not recognizing different performance demands in preamps, DAC I/V, filters, buffers, headphone driving
> 
> ...


 
   
  First, let me establish that I have no problem with what you said in this post, above - your mission is obviously noble.
   
  Quote: 





zilch0md said:


> Please give us said *pointers*.


 
   
  Here, I was requesting that you provide the very "pointers" for the material to which you believe a "newbie" should have access.  
  Quote: 





jcx said:


> the Sound Science forum was  created as a ghetto to keep discussion of double blind testing, the Science of controlled listening out of "regular" threads on the grounds that it turns into flame wars
> 
> so that is now where such discussion lives - you can search for comments on op amp rolling - or create a dedicated thread there for discussion around the topic - but with DBT, ABX, psychoacoustic Science allowed


 
   
  But here, in your most recent post, "newbies" are left wanting.  
   
  I've looked for this "Sound Science" forum, but cannot find it, and frankly, going only on your description of the forum, it seems to be some kind of leper colony for outcasts whose posts incite rage among those who regularly post to threads like "The Opamp Thread."  
	

	
	
		
		

		
			




   
  But, I'm still curious that this "Sound Science forum" might actually provide *technically and psychoacoustically valuable* information for newbies, that you believe could actually be consumed by a newbie to good affect. 
   
  So again, *please give us said pointers*.
   
  Something tells me that when a newbie gets to the this place of wisdom, it will be found indigestible.  That's the problem:  Those with a deep understanding of electrical engineering are unable to accept the fact that others have no choice but to experiment, in ignorance.
   
  Where should a newbie with a brain go, to escape the ignorance you've suggested is so prevalent in this thread?
   
  Thanks!
   
  Mike


----------



## wakibaki

http://www.head-fi.org/f/133/sound-science
   
  w
   
  It's simply not true that 'others have no choice but to experiment, in ignorance'. For anybody with a computer and internet access, ignorance is a choice.


----------



## Mad Max

Quote: 





soun said:


> Cheers zilch0md, the aim was definitely not to fry a new present that I wanted for years.  So yes, definitely asking before doing anything drastic.
> 
> 
> Thanks Mad Max, I did come across the same photo, so all good in terms of the chip orientation for when replacing.  Just no sure about if they are suitable at all.  I did read about buffer as well as actual opamp, so the bit about being able to load opamp into buffer is new to me as well, so more reading there I guess.  And lastly was definitely keen to learn more about voltage fitting etc.  So anymore insight on these are welcome.
> ...


 
   
  Yes, they're all compatible with the D12's 10V (+/-5V) supply.  That's what part of what I meant when I said that they should work, I should have been more specific.


----------



## jcx

http://www.head-fi.org/f/133/sound-science
   
  like any forum there a major limitations to technical content, discussions wander, newbies, wannabes drop in without reading any of the thread to add further diversions...
   
  but some pointers to the literature, some on the web can be dug out of some of the threads, occasional posts by recording engineers,
 EE circuit designers, science trained pros interested in audio, knowledgeable in experimental design, statistics, psychology
   
  for audio amplifier circuit design I'm afraid this head-fi sub forum is rather weak, the Headwise forum died, but archived content can be searched
   
http://www.diyaudio.com/index.php is one of the best I know of - but the headphone amp diy sub forum is still a small part


----------



## zilch0md

Thank you, gentlemen!


----------



## zilch0md

jcx, 
   
  So where in the Sound Science forum, are the articles that explain to newbies how to determine if an op-amp is compatible with a given device, such as Soun's D12?
   
  Seriously, I could pour through that forum for days and still not learn what I need to know. Not without asking questions.  And ultimately, I would have to trust the people who answer those questions, just as I have done when reading this thread - a thread which you've implied has little value. 
   
  It's very easy for people who have the knowledge to scorn those who experiment in ignorance, especially when your solution is so vague:  "Go read the sound science forum, because there's little of value to be found in this thread"  (paraphrasing).
   
  What kills me is that at no point in these recent posts has anyone (including me) suggested that Soun download and start reading datasheets for the op-amps he is considering.   And no one (including me) has suggested what questions he might ask of the D12 designers, that could be of use in determining whether an op-amp is compatible.  
   
  Putting myself in Soun's shoes, we've given him nothing with which he can educate himself so that he can make his own decisions.  Nothing.
   
  Mad Max, on the other hand, has come to the rescue with just the kind of recommendations I had suggested Soun wait to receive.  To me, trusting the experience of others makes a lot more sense than trying to educate yourself in the absence of any resource that covers the subject matter from A to Z.   Where is this material?   If it's in the Sound Science forum, where is it precisely?
   
  Until then, I think newbies would do well to ignore your concerns for the value of this thread.  
   
  Update:  I want to add that I can tell your heart in is in the right place, jcx - that you're not simply being elitist - but, I'm asking you to show more empathy still for those of us who don't have the first clue how to equip ourselves with the information that allows people like you to easily discern whether an op-amp is compatible - whether it can be "plugged in" without damaging either the amp or the headphone. 
   
  Thanks,
   
  Mike


----------



## zilch0md

Has anyone here read Ethan Winer's _The Audio Expert: Everything You Need to Know About Audio _?  It sells for only $46.71.
   
  If so, would Soun be able to discern which op-amps are compatible with his D12 having read this book?
   
   
  Maybe this would be more appropriate, but it sells for $157.88:  Ray Gayakwad's _Op-amps And Linear Integrated Circuits_.
   
  Or perhaps Frank R. Dungan's _Opamps & Linear Integrated Circuits & Technicians_ for $240.95.
   
  Here's a book with "op-amp" in the title, that's only $70.95:  Joseph Carr's _Electronic Circuit Guidebook, Vol 3 OP Amps_ - but it's not rated as highly as the others.
   
  The best reviews seem to be for Sergio Franco's _Design with Operational Amplifiers and Analog Integrated Circuits _- for $193.72.
   
  Has anyone here read any of these?
   
  Thanks,
   
  Mike


----------



## SpudHarris

Strangely enough Mike, I've been considering getting a decent book to expand my understanding for quite some time. A couple of those titles are on Amazon here in the UK. I'll be watching for responses to your post......

I agree 100% with your previous posts also. Hopefully something positive for those of us who want to learn will come of this.


----------



## wakibaki

The thing is, zilch, that just reading one of these books isn't going to hack it. In fact you probably haven't even got the precursors to understand these books (other than the Winer one).
   
  Trying to take your anger out on people who _have_ made the effort to understand the subject doesn't improve the situation, however.
   
  The first clue as to how to improve the situation is to learn to use google.
   
  First try reading everything Wikipedia has to say on the subject of opamps, you can find that using google. Anything you don't understand, look it up using google.
   
  Next you might like to read Walt Jung on opamps:- http://www.analog.com/library/analogDialogue/archives/39-05/Web_Ch6_final_I.pdf. It's one of the best things written on the subject, and it's *free*.
   
  Unfortunately, it takes literally years of effort to gain anything approaching a professional appreciation of the subject.
   
  None of this will happen unless you make the effort, and it certainly won't happen as long as you keep trying to pass the responsibility for your lack of education onto those who happen to have one.
   
  w


----------



## Mad Max

zilch0md, please don't imply that I'm reliable as my experience and knowledge on circuits is approximately _zilch._
  lol


----------



## zilch0md

Quote: 





wakibaki said:


> The thing is, zilch, that just reading one of these books isn't going to hack it. In fact you probably haven't even got the precursors to understand these books (other than the Winer one).
> 
> Trying to take your anger out on people who _have_ made the effort to understand the subject doesn't improve the situation, however.
> 
> ...


 
   
  Excellent points you've made - especially the line I've highlighted, above, as it supports my argument beautifully.  
   
  Your point - that anyone can learn anything, _if they put enough time and effort into it,_ is absolutely valid.  
   
  I think it's safe for all of us to assume that when Soun asked for help, he did so with the hope of rolling op-amps sometime soon - not "*after literally years of effort" *to gain  *"a professional appreciation of the subject."*
   
  So, as much as I agree with the point you're making, it does not support jcx' contention that this thread is of little value or that the Sound Science forum is of greater value.  Your point only supports his contention that one should educate oneself before rolling op-amps, rather than relying on others' recommendations - but at least you are acknowledging that this can only happen at tremendous cost - literally years of effort!  Thank you for making that clear to everyone.  
   
  Given that we can't all be experts on every subject, please look the other way if you have to, while I continue to rely on the expertise, opinions, hunches, truths and falsehoods of others.  My fields of interest are far too numerous to exert "literally years of effort" to become self-sufficient with each of them.  
   
  I'm OK with seeking and trusting others.  If anyone advises me incorrectly, hopefully, a lurking guru will jump in and set me straight - in this forum and every other forum I frequent.  Meanwhile, I'll continue to use Google to research those topics that can be mastered in a few days, rather than literally years.  I'll hire a neurosurgeon, if I need one.
   
  Thanks,
   
  Mike
   
  .


----------



## zilch0md

Quote: 





mad max said:


> zilch0md, please don't imply that I'm reliable as my experience and knowledge on circuits is approximately _zilch._
> lol


 
   
  Hey, I resemble that!


----------



## qusp

I learn something new every day, I make mistakes regularly when I push into areas I dont know, but I always try to be prepared by doing the reading. I learned through osmosis, one day things just start to click, the Walt Jung papers are an excellent recommendation, as are the writings of the sadly recently demised Jim Williams of linear technologies, who wrote the app notes for and designed many well liked opamps and regulators. ( here is some background on the man and there is a link to his archived writings at the bottom of the page, he had a great way of injecting humor and deep insight into the technology). 

I learned practically everything I know through the internet and my own application, I have no related degree, just battle-scars =) the writings of Erno Borbely are a great start into discrete design for audio and for an understanding of Jfets, Mosfets etc. my knowledge is dwarfed by those I learn from and for that I can wholeheartedly recommend DIYAUDIO as well. diyaudio has everything from basic application, some nonsense , right through to insider industry knowledge that cannot be found in any datasheet; straight from the 'horses mouth' like in the discrete opamp open design thread currently. I still have much to learn, but these days I know where to look/start.

in short, ibasso supplies the rolling kit with the dac/amp, good chance they are all compatible with the operating conditions of the unit. the D12 probably only has a dual opamp socket which you can use singles on a dual adapter and 2 buffer sockets if its like the D10

correction it has 
1 x dual opamp socket
2 x single opamp sockets
(these do the voltage amplification, they are the VAS)
1 x dual opamp socket for buffers

but you can only use dual opamps as buffers, due to only a dual socket) you could use a dual adapter here to use 2 singles, or with some effort modify one fopr using 2 x BUF634 current buffers.


----------



## zilch0md

Nigel,
   
  Quote: 





spudharris said:


> Strangely enough Mike, I've been considering getting a decent book to expand my understanding for quite some time. A couple of those titles are on Amazon here in the UK. I'll be watching for responses to your post......
> I agree 100% with your previous posts also. Hopefully something positive for those of us who want to learn will come of this.


 
   
  I've benefited greatly from your advice, despite your lack of education.  Please continue your malpractice with my blessings, but by all means, pursue a better understanding, as your passion for knowledge moves you.
   





   
  Mike


----------



## wakibaki

Quite honestly, zilch0md, I think your response is disappointing.
   
  I'm not surprised by it, you want to continue swapping opamps and talking about it. If you really paid attention to what jcx wrote, and the stuff in the Sound Science forum, you'd have to give that up almost in its entirety.
   
  Sometimes our illusions matter more to us than the truth, when we have a big emotional investment in them.
   
  I want to continue designing bits of electronics and talking about them, and electronic design, and sharing what I know. So I try to avoid getting into these arguments, because they rarely have a positive outcome. I'm not always successful, though, and anyway, you never know your luck. 
   
  I have external confirmation of my ideas, there's certainly no way that many of the things I build would work at all if I didn't have a good grasp of _how_ they work. That's how I get satisfaction from what I do, I build things, they work, it reinforces my world picture. What they call a vicious circle 
	

	
	
		
		

		
		
	


	




.
   
  Of course sometimes they don't work, the universe spits them back at me, and I'm forced to change my ideas. Or at least acknowledge that I made a mistake. They do happen. As they say, the man who never made a mistake never made anything.
   
  I recommend this activity to you, or some other truly constructive activity. I don't recommend carrying on the way you are going, it's pointless and unrewarding by comparison. Opamp rolling isn't even a hobby, it's just a _habit_.
   
  Again, I don't expect you to be very happy when I say this, I probably wouldn't take too kindly to being told that what I do is pointless and unrewarding, but there's no point in dissembling. Just try and accept that it's said with the best of intentions. I know you _believe_ in it, but _I_ don't _have_ to _believe_ in what I do, I have the proof in my hands.
   
  You say that you don't have any choice. I can see how you might feel that, but I know that you _do_ have a choice, uncomfortable as it might be on occasion to acknowledge it. If you live forever within your comfort zone, you look forward to a life without progress.
   
  So, all you opamp rollers, get out there, grasp the nettle, get out of the paddling pool and learn to swim. Or whichever mixture of metaphors takes your fancy. You know it makes sense.
   
  w


----------



## zilch0md

I hear you loud and clear:  I shouldn't do any rolling until I've mastered the subject matter, even though it can take years to actually do so.
   
  Thank you for caring, and Merry Christmas!
   
  Mike


----------



## Armaegis

It frustrates me sometimes when it comes to learning this stuff. I sit on the edge wondering how deep am I really going to sink myself into this. I'm capable, but time and resources are the limiting factor. Sure, I can design a rudimentary circuit, and I've built the odd one here and there as proof of concept that yeah I can actually get it to work. But then I look at the mountain of possibilities beyond that, all that stuff beyond following the sample diagram in the spec sheet, and I start to read, then read some more, then realize oh crap if I really want to get into this, and I mean *really* get into this, it's going to cut even more heavily into my time. Then I'll need more tools, more equipment, more *toys*... 
   
  So with a bit of sanity/sadness, I pull back. "This way lies madness" I tell myself. I can only support so many vices at one time. Well, unless I can make money doing so. Man, I spent all these years doing my PhD in a decidedly non-audio related fields (unless you want to discuss metallurgy and cables... but I gave up on sound science a long time ago already). If only I wanted to be an audio guy instead of a blacksmith when I was a teenager, perhaps I would have gone down a different path eh?


----------



## SpudHarris

Quote: 





armaegis said:


> It frustrates me sometimes when it comes to learning this stuff. I sit on the edge wondering how deep am I really going to sink myself into this. I'm capable, but time and resources are the limiting factor. Sure, I can design a rudimentary circuit, and I've built the odd one here and there as proof of concept that yeah I can actually get it to work. But then I look at the mountain of possibilities beyond that, all that stuff beyond following the sample diagram in the spec sheet, and I start to read, then read some more, then realize oh crap if I really want to get into this, and I mean *really* get into this, it's going to cut even more heavily into my time. Then I'll need more tools, more equipment, more *toys*...
> 
> So with a bit of sanity/sadness, I pull back. "This way lies madness" I tell myself. I can only support so many vices at one time. Well, unless I can make money doing so. Man, I spent all these years doing my PhD in a decidedly non-audio related fields (unless you want to discuss metallurgy and cables... but I gave up on sound science a long time ago already). If only I wanted to be an audio guy instead of a blacksmith when I was a teenager, perhaps I would have gone down a different path eh?


 
   
  Armaegis, I think you have summed up the thoughts of the majority on this thread, nicely put.....
   
  Me? I'm going to carry on regardless.


----------



## analogsurviver

Quote: 





armaegis said:


> It frustrates me sometimes when it comes to learning this stuff. I sit on the edge wondering how deep am I really going to sink myself into this. I'm capable, but time and resources are the limiting factor. Sure, I can design a rudimentary circuit, and I've built the odd one here and there as proof of concept that yeah I can actually get it to work. But then I look at the mountain of possibilities beyond that, all that stuff beyond following the sample diagram in the spec sheet, and I start to read, then read some more, then realize oh crap if I really want to get into this, and I mean *really* get into this, it's going to cut even more heavily into my time. Then I'll need more tools, more equipment, more *toys*...
> 
> So with a bit of sanity/sadness, I pull back. "This way lies madness" I tell myself. I can only support so many vices at one time. Well, unless I can make money doing so. Man, I spent all these years doing my PhD in a decidedly non-audio related fields (unless you want to discuss metallurgy and cables... but I gave up on sound science a long time ago already). If only I wanted to be an audio guy instead of a blacksmith when I was a teenager, perhaps I would have gone down a different path eh?


 
  I didn't read this, I didn't read this, I DID NOT read this - damn, I did !
   
  That pulling back hurts sometimes - well, not only sometimes, it keeps reoccuring - at the oddest of times.
   
  We have a saying, that goes, roughly translated, like this: Where went the bull, the rope should follow ...
   
  It was way past the age people normally decide what path to take in their lives that I realized audio , one way or another, IS my thing - or I would end up forever yearning "what if". 
   
  Better to fail than the above - therefore I soldier on. But sometimes it is hard.


----------



## zilch0md

Quote: 





spudharris said:


> Armaegis, I think you have summed up the thoughts of the majority on this thread, nicely put.....
> 
> Me? I'm going to carry on regardless.


 
   
  Yes and yes.
   
  Thus far, for me, the rewards have outperformed the undeniable but reasonably affordable risks. I've not yet destroyed anything, but my ears are very happy, having blindly rolled the dice, again and again, ignorantly blundering my way to an obviously superior audio experience.
   
  In short, I've been touching the hot stove without getting burned - and I'm rewarded for doing so.
   
  Mike


----------



## Armaegis

March on, brother, march on!
   
  Welcome to head-fi, sorry about the... fingertips?


----------



## eugenius

I recently got a Claro Halo XT for HTPC duties (movies mainly). I'm using a Harman Kardon Signature 2.1 power amplifier and Jamo C80 series speakers.

I want to roll some op-amps in it and I have some questions:

1) What is the output impedance of the headphone jack and the RCA outs? Can I influence this by changing opamps? I'd like an under 2ohm headphone out impedance and under 100ohm RCA out impedance.

2) Which position (I/V, buffer) has the most influence on the sound? I presume I/V, is that right?

3) What's the voltage this card runs it's op-amps at (including XT)?

4) I see there's an I/V and a buffer position on the HALO card and just three dual opamps on the XT daughter board. What do the op-amps on the daughter board do, I/V or Buffer? If the opamps on the XT do I/V, are those outputs buffered with another opamp/buffer on the PCB? I want to run the same opamps/buffers on all channels if possible. 

6) If there's a single opamp on the XT, has anybody you know (or yourself) tried the AD8397 high current dual opamp in there?

7) If I want to keep all channels the same, can I leave the buffer sockets empty or do I need some kind of bypass adapter?

8) I was thinking about 2xAD797BR on DIP8 adapters for I/V (seems a popular choice) and for buffers I don't have any idea ... BUF634? What other buffers do you recommend? Do you have a list of opamps that are safe in the Halo XT?

Thanks!


----------



## wakibaki

The HT Omega website says the Claro Halo XT uses a TPA6120A2 to drive the HP output. You cannot readily replace this part, as it is SMT with a central heatsink pad on the underside, removing it from the board might be possible with a hot-air desoldering station, but it will not be easy, and anyway what would you replace it with? It is a dual amplifier with independent supply in a 20-pin package with 10 pins N/C. An AD8397 will not fit the footprint, and anyway is probably an inferior part, certainly it has no short-circuit tolerance and will not drive as much current (700mA P/C).
   
  The TPA6120A2 can be configured to provide <2ohm output impedance, but the datasheet recommends at least 10 ohm series impedance to obviate oscillation by isolating the amplifier output from any load capacitance. It's possible to replace this resistor with an inductor, but if a ferrite-cored type is chosen it _may_ negatively impact the THD depending on exact type. Of course the device may already be so configured.
   
  w


----------



## eugenius

Wakibaki, thanks for answering, but was thinking of using AD8397 as a buffer not as a TP6120A2 replacement. As I understand it, the AD8397 is an opamp that doesn't need an extra buffer as it can give more than enough current, so by putting AD8397 all around (obviously with the buffer position bypassed on the main card) you can have all channels with the same config.

In the mean time I received some answers from HT Omega (which I might add, seem to threat their customers well and actually respond to questions well and fast). The answers:

- The Zout of the headphone jack is 8ohm. 
- The Zout of the rca's is 150ohm. Both acceptable I think, unless you have Grado's and you like super tight bass. Any headphone over 60ohm should be great.
- The card runs it's op-amps at 12V.
- The opamps on the XT are buffers.
- The recommend the LME49790NA and the OPA2132P. They have users reporting success with OPA627 (ha!) and users asking about AD797 but no reports with it. 

So, can I use AD797 all around and BUF634 in the buffer position on the main card? What are some safe (tested) opamps for this card?


----------



## kazaakas

Can anyone help me recollect wether the OPA627, ADA4627 and LME49860 will become warmer/darker or colder/brighter when biased into class-A with 3.3KOhm resistors?


----------



## Mad Max

Depends on the circuit.  Class-A isn't really worth it with 4627, instead add a 0.02uF ceramic capacitor and two Vishay MKP1837 capacitors across the power supply pins if you intend to use it in the M-Stage.  The two film caps should be combined like this (frontmost, center opamp module).  This will give you far more improvement with 4627 than any sort of class-A biasing.


----------



## qusp

myself I stick to low inductance ceramic or thin film SMD, perhaps SMD PPS film. completely agreed, high class opamps are already running output stages in Class A or high bias AB for most loads. besides a CCS would be preferred for bias in a case/device that responds to it. indiscriminately biasing into class A is of little benefit IMO


----------



## kazaakas

Quote: 





mad max said:


> Depends on the circuit.  Class-A isn't really worth it with 4627, instead add a 0.02uF ceramic capacitor and two Vishay MKP1837 capacitors across the power supply pins if you intend to use it in the M-Stage.  The two film caps should be combined like this (frontmost, center opamp module).  This will give you far more improvement with 4627 than any sort of class-A biasing.


 
  Was actually going to try them out with my soundcard, got a LME49860 in the M-Stage now, which I'm really digging, was wondering what class-A biasing could do


----------



## Armaegis

Anyone have any recommendations for where to get soic to dip adapters? I've seen the cimarron stuff, but surely there's cheaper than that somewhere. I'm looking for some single to single soic-to-dip8 as well as some 2xsoic to dip8 dual.


----------



## Mad Max

fleaBay, iBasso


----------



## Armaegis

Any particular vendors on ebay that are good for that?


----------



## Mad Max

diyinhk, tube_buyer, u-barn, and audjade_chn
   
  sorch-audio, hifiic, hifi-szjxic, and jk_parts look good but I haven't tried out their stuff.
   
  I like iBasso's best for being compact, very sturdy, and with relatively even-length traces, but they only sell single adapters.  The fleabay adapters are all taller and better suited for adding extra caps and what not.


----------



## tomb

Quote: 





armaegis said:


> Anyone have any recommendations for where to get soic to dip adapters? I've seen the cimarron stuff, but surely there's cheaper than that somewhere. I'm looking for some single to single soic-to-dip8 as well as some 2xsoic to dip8 dual.


 
  An SO8 to DIP adapter from Cimarron is $3.  Aren't we shaving the savings a little thin?  Use two of those with a $3 single-to-dual DIP adapter and you have your 2nd request for a grand total of $9.


----------



## Armaegis

A buck here, a buck there, one or two dozen adapters later and it starts to add up.


----------



## Mad Max

It's better to have single-to-dual DIP8 adapters only for DIP8 chips.  Two soic8 single chips should go on a 2x-soic8-to-dual-dip8 adapter instead and not soic-to-dip adapters + single dip-to-dual-dip adapters as tomb suggests. The latter is just an unnecessary mess of extra adapters/sockets.
   
  Cimarron's adapters are like Practical Devices', too flimsy in my opinion.


----------



## tomb

Quote: 





mad max said:


> It's better to have single-to-dual DIP8 adapters only for DIP8 chips.  Two soic8 single chips should go on a 2x-soic8-to-dual-dip8 adapter instead and not soic-to-dip adapters + single dip-to-dual-dip adapters as tomb suggests. The latter is just an unnecessary mess of extra adapters/sockets.
> 
> Cimarron's adapters are like Practical Devices', too flimsy in my opinion.


 
  It's better to not have adapters at all.  Cimarron Brown Dogs were sold by Tangent for years and I've had them in portable PIMETAs for about 5 years without a hitch.


----------



## Mad Max

Unavoidable with SOIC chips and equipment with socketed opamps unless you are willing to solder the opamps directly to the PCB and not roll opamps.


----------



## SpudHarris

I have just been reintroduced to an oldie but goodie... AD743JN !

What do you guys think? I have had these for a while although discontinued about 7 years ago. Ryuzoh from MST (Fi-Quest amp fame) recommended I try them in my Fi-Q and I have to say I'm a little shell shocked at how great they sound, the best OpAmp I have tried in the Fi-Q so far (and I'm a roller).....

Anyone care to give them a go again? Type this product into Farnell and it spits back ADA-4627 as a comparable replacement, I'm looking at you Mad Max 

Unfortunately they are current eaters so not brilliant for portable use as they kill run times. My Fi-Q never leaves the house now as it is one of my favourite home amps for the HE-6.


----------



## leeperry

Quote: 





mad max said:


> diyinhk, tube_buyer, u-barn, and audjade_chn
> 
> sorch-audio, hifiic, hifi-szjxic, and jk_parts look good but I haven't tried out their stuff.
> 
> I like iBasso's best for being compact, very sturdy, and with relatively even-length traces, but they only sell single adapters.  The fleabay adapters are all taller and better suited for adding extra caps and what not.


 
   
  There's also this seller who's always kept on saying that his adapters were far more technically advanced than the browndogs: http://www.ebay.com/itm/230797790202
   
  Facts are that $3 a pop for a browndog is outrageous when you can easily guess that he buys them for 10 cts or so. It should also be noted that their pins aren't even soldered onto the adapter for $3, they're only assembled together with a more than likely very poor actual contact surface. The guy has/had a niche, and he prolly was one of the first to sell this kind of adapters....that are mostly meant to be used by bored rollers ^^
   
  Quote: 





jcx said:


> the overwhelming majority of "recommendations" here ignore/don't mention the circuit application, or even the power supply Voltages - and even within a category of a specific audio circuit type the engineer can make differing decisions on circuit details that affect op amp choice


 

 I believe most everyone here is well aware that opamps aren't friggin leggos but we're children at heart and it just feels good to solder chips with cryptic model numbers read in audiophool discussion threads, install them as if these were leggo bricks and seek any SQ change 
	

	
	
		
		

		
			




   
  But yeah, rolling opamps is bound to fail........only very experienced technicians with an oscilloscope and the know-how have any actual use for swappable opamps sockets.
   
  I believe most everyone here has tried all the most expensive opamps by rolling them blindly, and found out later on that well implemented cheaper opamps would provide a far less colored and much more enjoyable experience.


----------



## Mad Max

Quote: 





spudharris said:


> I have just been reintroduced to an oldie but goodie... AD743JN !
> What do you guys think? I have had these for a while although discontinued about 7 years ago. Ryuzoh from MST (Fi-Quest amp fame) recommended I try them in my Fi-Q and I have to say I'm a little shell shocked at how great they sound, the best OpAmp I have tried in the Fi-Q so far (and I'm a roller).....
> Anyone care to give them a go again? Type this product into Farnell and it spits back ADA-4627 as a comparable replacement, I'm looking at you Mad Max
> 
> ...


 
   
  I've heard read good things about AD743 around the forums, but I only have AD744 (ceramic dip and plastic dip), which is quite nice if not for the less than excellent noise floor.


----------



## DefQon

Quote: 





leeperry said:


> I believe most everyone here is well aware that opamps aren't friggin leggos but we're children at heart and it just feels good to solder chips with cryptic model numbers read in audiophool discussion threads, install them as if these were leggo bricks and seek any SQ change
> 
> 
> 
> ...


 
  Can't believe what I'm reading and this is coming from you leeperry 
	

	
	
		
		

		
		
	


	




, correct me if I'm wrong but you used to be one of (along with that majikal guy from Poland who got banned) head-fi's most prolific opamp roller.


----------



## tomb

Quote: 





mad max said:


> Unavoidable with SOIC chips and equipment with socketed opamps unless you are willing to solder the opamps directly to the PCB and not roll opamps.


 
  Right.  I forgot for a minute that this is the DIY section.


----------



## leeperry

Quote: 





defqon said:


> Can't believe what I'm reading and this is coming from you leeperry
> 
> 
> 
> ...


 

Majkel is still very much around and yes his opamp thread was the major bait to blind rolling for me 
	

	
	
		
		

		
		
	


	



   
  The only diff is that he's an EE so he can make sure that these little cranky things are happy, I cannot.
   
  Well, blind rolling opamps is mad fun as everyone will agree on this point but I've come to realize(like many others as well) that you can't magically improve everything without caring about the surrounding circuit. I recently played smart by installing an army of AD797B's in the Asus Essence One, but very rarely I would get wooshing sounds that are rather easy to pin down to oscillation.
   
  You can prolly roll "unity gain stable" chips such as OPA2132 and so as these are notoriously very "sociable" but to me the big culprit is dual opamps that always sound extremely colored IME, and even TI acknowledged the problem: http://www.ti.com/product/opa1642
   
  Quote: 





> The dual and quad versions feature completely independent circuitry for lowest crosstalk and freedom from interactions between channels


 
   
  Which means that all the chips that don't have this feature clearly stated in their datasheet share the same circuit ^^
   
  But luckily design engineers are starting to realize that, and even Creative Labs internal soundcards now use two single opamps in their buffering output stage: http://www.guru3d.com/articles_pages/sound_blaster_x_fi_titanium_hd_review,11.html
   
  I guess people are right, with a strong motivation and a used oscilloscope anyone could learn the opamp's 101 but do I have time/care that much? I also used to make electronic music like a decade ago, but when I listen to "Boards of Canada" or "Ed Rush & Optical" I realize that I will never make such good music and that any further attempt will be a waste of my precious time.
   
  There are EE's who are specialized in making great sounding gear, that's a job in its own right you know and I'm not presumptuous enough to think that I can magically improve everything by buying the most expensive opamps(ADA4627-1B, OPA627SM or whatever) and installing them like leggo bricks as a magic bullet to audiophoolism


----------



## PChoon

Hi guys i need your experience in opamps.
   
  i have a graham slee voyager that i really love.
   
  recently i tried opening it up to take a look on the insides.
   
  and i saw that it has a AD823AN op-amp which i could roll.
   
  is there by any chance any one here has tried changing the op-amp?
   
  or is there recommendations?
   
  thank you.


----------



## Lil' Knight

So I've just found out there is a TI distributor pretty near my place. Thinking of stopping by to pick up some nice opamps and DACs from them.

Anything worth looking at, besides the OPA827, LME49710, LME49720 and LME49990? I know the 49710 and 49720 has metal can package. Any other LMExxxxx series that have this type of package?


----------



## leeperry

don't believe the metal can hype IMO/IME, and OPA1641 should be on the top of your list if you can solder.


----------



## Lil' Knight

How does the OPA1641 stand against the OPA827? I have a boatload of OPA827s, just curious if there is anything else worth considering...


----------



## SpudHarris

leeperry said:


> don't believe the metal can hype IMO/IME, and OPA1641 should be on the top of your list if you can solder.




X2

1641 is amazing!


----------



## leeperry

Quote: 





lil' knight said:


> How does the OPA1641 stand against the OPA827?


 

 I really don't like 827(when rolled blindly 
	

	
	
		
		

		
			





) and just for the record this XMOS based DAC is using OPA1642 as DAC LPF


----------



## Mad Max

Quote: 





lil' knight said:


> How does the OPA1641 stand against the OPA827? I have a boatload of OPA827s, just curious if there is anything else worth considering...


 
   
827 rules, but needs extra bypass caps to shine.
 Not as many as in that linked post, though, LOL!


----------



## Lil' Knight

leeperry said:


> I really don't like 827(when rolled blindly :rolleyes: ) and just for the record this XMOS based DAC is using OPA1642 as DAC LPF :wink_face:



That's a nice, little DAC. Love the teflon pcb.

I'll pick up some OPA1641s to see how they perform then. Mainly use these opamps in a super regulators and servos in my headamp though.


----------



## 12Bass

OPA1641 is decent if low quiescent current is a concern; I prefer the sound of OPA827. That said, I think that ADA4627-1 sounds better than both.


----------



## Lil' Knight

Yet another JFET input opamp... Thanks for the suggestion, gonna order some.

The way AD codename those xxx627xx and xxx637xx make me think they are direct replacement for the 627/637. Not really sure about this though, gonna dig deeper.


----------



## Mad Max

I'd be surprised if they were.


----------



## jcx

I think they are targeted at the same markets, intended to compete with the BB parts
   
  one of the biggest advantages of the OPA627/37 is the AC CM input impedance linearity, no good measure is shown on standard datasheets so its hard to say if they're really competitive


----------



## Huxley

Folks a little input please, i have a P4 warbler which i love and im just getting into rolling opamps?

Does anyone know of any fitting guides, or any do's and dont's?

I have ron's topkit on order, along with some OPA627BP

But im also thinking of getting OPA2111AM and OPA1641 to throw into the mix.

Im currently using AD797 with stock buffers and so far im liking the sq improvement, though i do tend to favour a darker presentation.


----------



## H22

A bit new to the thread, been lurking for a while though. I recently put 3 OPA1641's in a PPAv2 style amp, seems to work very well in this amp, but i notice a grainy-ness to the upper-mids, anyone else notice this?
   
  joe


----------



## Armaegis

Maybe it was distortion?


----------



## Apocalypsee

Just got a cople of metal cans LME49720HA. Replaced it on my Xonar HDAV1.3 on buffer stage (previously DIP LME49720NA) and replaced the utput opamp from LM4562 to LME49720NA. I can't believe the clarity and the soundstage the HA offers over the NA. It sounds like a totally new opamp! Much MUCH clearer and more defined.


----------



## zilch0md

Awesome!   Ears be happy!


----------



## WiR3D

Quote: 





apocalypsee said:


> Just got a cople of metal cans LME49720HA. Replaced it on my Xonar HDAV1.3 on buffer stage (previously DIP LME49720NA) and replaced the utput opamp from LM4562 to LME49720NA. I can't believe the clarity and the soundstage the HA offers over the NA. It sounds like a totally new opamp! Much MUCH clearer and more defined.


 
  hows the bass?
   
  crap I'm betting.


----------



## Apocalypsee

Quote: 





wir3d said:


> hows the bass?
> 
> crap I'm betting.


 
  Not really crap, it got less punch than before but I'm no basshead so its a non issue to me. I don't recommend people to get this if they wanted bass, because there isn't much of it. LME49720 just screams details and soundstage but not bass.


----------



## WiR3D

Quote: 





apocalypsee said:


> Not really crap, it got less punch than before but I'm no basshead so its a non issue to me. I don't recommend people to get this if they wanted bass, because there isn't much of it. LME49720 just screams details and soundstage but not bass.


 
  Yeah I know, its their flaw, that and some wonky upper mids sometimes. 
   
  if you like smooth go THS4032 - or if you want as much detail as detail as possible without going discrete AD797 (its gamble on whether it will oscillate) and to me its a bit harsh, I prefer a smoother sound. Both have huge soundstage, the AD797 having the most, and the THS4032 having the better imaging. I had 2x LME49710 metal cap mounted on a PCB for comparison, which is better then the LME49720 and the AD797 and THS4032 slaughtered them in everything. (Listening with AKG's on my STX)
   
  Those are probably the 2 with the most clarity, and the LME49990.
   
  and BTW 3x THS4032 (2 in I/V and one in Buffer) is too much, its too smooth.


----------



## H22

I'm noticing some unnatural sounds in the upper mids with the  OPA1641, anyone else notice this?


----------



## Armaegis

Are you sure it isn't distortion?


----------



## H22

Quote: 





> Are you sure it isn't distortion?


 
  No, i have know way of knowing if it is distorting or not.
   
  Everything else sounds fine, but some frequencies just sound garbled ( highly technical term there ).
   
  Did not know it was possible for an op-amp to only distort certain frequencies.
   
  what would one do to prove or disprove this?


----------



## doco

looking into getting some better op amps than the stock amp (4556AD JRC) and wanted to see if anyone can recommend one for my taste. i like details, balance, natural, clarity, smooth (but not too smooth), and a bit on the bright side (but not too bright). would the LME49990 suit me well for this or?...
   
  here is the layout of the board i will be placing it in and the ebay page of the specs for it
  http://www.ebay.com/itm/Professional-HiFiMAN-EF5-Headphone-Amplifier/170696111860
   
  thanks!


----------



## DingoSmuggler

Quote: 





doco said:


> looking into getting some better op amps than the stock amp (4556AD JRC) and wanted to see if anyone can recommend one for my taste. i like details, balance, natural, clarity, smooth (but not too smooth), and a bit on the bright side (but not too bright). would the LME49990 suit me well for this or?...
> 
> here is the layout of the board i will be placing it in and the ebay page of the specs for it
> http://www.ebay.com/itm/Professional-HiFiMAN-EF5-Headphone-Amplifier/170696111860
> ...


 
  Since they are directly driving the headphones, the stock NJM4556 are a good opamp due to their high current output and good performance into low impedance loads.
  A lot of the opamps that are popular choices use in a buffered gain stage, aren't great at directly driving headphones.


----------



## Synthax

Hello Fellows,
  Do you know if Burson descreet op amp fit to CMoy BB ? Will it work? I know AD8066 work, but look for some BIG upgrade


----------



## Mad Max

If the Cmoy has a huge case, then yes.  The opamp might be almost as big as the cMoy circuit, LOL!


----------



## DingoSmuggler

Quote: 





synthax said:


> Hello Fellows,
> Do you know if Burson descreet op amp fit to CMoy BB ? Will it work? I know AD8066 work, but look for some BIG upgrade


 
  For that sort of money, DIY a better amp.


----------



## Mad Max

That, too, lol!


----------



## Synthax

Well, the dimensions are not a problem as I'm thinking of putting my cmoy to new case. With bigger battery. But my question is if this Burson Op Amp work with my jds cmoy bb? And if it is worth to make it?


----------



## Mad Max

I don't want to come off as abrasive, but I have to agree with Dingosmuggler.  Build a better amp with that money, no opamp will make a big enough difference.  A better amp will sound better than any cmoy with the burson opamp installed.


----------



## ecohifi

Has anyone tried the AD844?


----------



## razzz42

Using a Prodigy HD2 DE (VIA driver 5.12.1.3656, no VIA software), I went from an old configuration of (2)AD797BR and (1) 627AU to new configuration of (2) LME49990MA and (1) 627AU. or without the 627AU LT1028ACN8 in the output (needs this adapter).  Listening with either ATH AD700 (open) or ATH A900X (closed).
   
  For a point of reference, listened to Donald Fagen - Morph The Cat - Mary Shut The Garden Door - 2006 in FLAC  Wavpack via Media Player Classic and The Very Best Of Fleetwood Mac - Everywhere - 2009 remastered from the original tape but well done for back in the day (1985-1987),  Hummin' To Myself - Linda Ronstadt - Hummin' To Myself - 2004  and a recent movie with Pitch Perfect (2012) Blu-Ray (DTS) 24bits, 48KHz sampling.
   
  To my ears: LME49990MA beautiful on the mid and esp. high end. Lacks a bit on the low end but I prefer the detailed highs as there is much going on in that range. Compared to the old configuration the AD797BR has more low (bass) range and is missing an area between the upper mids and high range. LME49990MA covers the entire mid to high range with very good separation, details and clarity, bass is in the background somewhat but maybe the new chips will break-in, both headphones are broken in already.**
   
  Because of LME49990MA clarity, I prefer listening with my AD700's staging and highs response, Most ATH always have good voice range, so no problems there.
   
  Through my Klipsch Ultra 5..1 sub, the bass is very clean. So the jury is still out if  the LME49990MA is producing a more natural clean bass sound versus the AD797BR coloring the bass or highlighting it to much. Having the open headphones on with the sub on pumping out the bass is a real plus.
   
  ** Bass only slightly highlighted. More bass showing up after 10 - 20 hours of breaking in the LME49990MA chips, can't really explain it but just starting booming better but still has the cleanness in bass sound that I am not use to. Turned my AD700 into a well balanced headphone. My A900X are turning out to be very capable phones minus some staging of course.
   
  Because the LME49990MA is my first opamp that was specifically tailored for music [Discrete? (according to the literature)] that I have used versus opamps that had other uses (ex. MRI machines or phone banks) but also worked with music and human hearing ranges_, I am finding the _LME49990MA a great sounding _opamp, very clean sounds throughout even the bass range being clean is something different to my ears.  _
   
  The following opamps are all used on their appropriate dual adapter boards. LME49990MA stayed on-board and I only exchanged in the output socket. Because of the LME49990MA the output opamps I tried below have a great signal to work with and give good benefits depending what you prefer...
  *OPA627AU in the output seems to add a little unnecessary color to the sound,
  sounds better without them/it.
  *AD797BR in the output, more highlighted bass now with the highs slightly more pronounced (owing to more hiss present in poor recordings) maybe a hair tinny in the highs.
  *AD8066AR in the output favors the bass, not in bad a way but colors/puts its tone even on a hum of a bad recording. Nice if you like your bass sounds.
  *LT1028CN8 in the output makes the bass sound a bit more believable but the very highs suffered (purchased this model by mistake).
  *LT1028ACN8 in the output gives clarity and separation throughout the ranges causing great staging, favors the highs, lows slightly hidden in the background (my favorite output chip so far).
   
  Some dual channels chips that didn't require an adapter board...
  *NE5532N in the output makes no changes to the signal other than enhancements like turning up the volume across the entire range at once, very very clean sounding.
  *LT1364CN8 in the output favors the highs and enhances the clarity along with staging with a little bass boost. Very clean as well (like its brother LT 1028CN8 above).
  *AD827JNZ in the output favors the lows to mids, brings them forward and puts the highs in the background. Very strong and realistic lows with a trade off of losing some detail in the highs. (So far best at handling lows)
   
  Listened with, AD700 and A900X headphones.


----------



## blizzu

Hello to everyone ! My first post here 
  Does the date code matter on opamps?
  Any difference between AD797BRZ 06+ and 12+ ?


----------



## whirlwind

I recently bought a BSC cmoy with a TLE 2082 op amp in it.
   
  Anybody have a small list of op-amps that would pair well with this 9 volt version cmoy and my Grado headphones?


----------



## DutchGFX

So today I built a cmoy, and it seams, at listening level and louder, it gets pretty distorted. I didn't use a socket, I soldered directly to the opamp. Is it possible that I fried the OPAmp by keeping the iron on too long?


----------



## Mad Max

That is one possibility.  Have you reflowed all solder joints not directly connecting to the opamp?  And when you reflow the joints on the chip, be sure to use copious amounts of flux to help disperse heat and avoid damaging the opamp.
  Also double check the wattage and resistance of each resistor to make sure that you didn't damage them.
  It would probably be better to start your own thread on the matter or post in a thread dealing with cmoy construction (that isn't terribly old).


----------



## DevilsRightHand

Hello boys & girls
 I was about to buy an Ibasso D12 amp (used) so I went ahead and ordered the opamp kit they sell on the official web site. The D12 deal fell through but I still got the kit. 

My question: Can I use the opamp chips that comes in the iBasso opamp rolling kit (listed below) in a Cmoy V2 by JDS Labs?

ADA4841-2
AD8532
LMH6643
AD8656

Thanks for the help


----------



## razzz42

Quote: 





devilsrighthand said:


> Hello boys & girls
> I was about to buy an Ibasso D12 amp (used) so I went ahead and ordered the opamp kit they sell on the official web site. The D12 deal fell through but I still got the kit.
> 
> My question: Can I use the opamp chips that comes in the iBasso opamp rolling kit (listed below) in a Cmoy V2 by JDS Labs?
> ...


 
  I would like to see the answer to you question also.  Don't have any of the amp/DAC you mentioned. The V2 being an amp, only has one output buffer socket which I would think it to be dual channel for stereo output. The Basso looks to be all single channel sockets because it has 4 op-amp sockets and 4 output sockets, 8 in total.
   
  I think the chips you listed are all single channel chips for a buffer out socket. If I am not mistaken, you need a dual channel chip in the output socket for the V2.
   
  There are other specific titled threads here or elsewhere that discuss the amp/DAC models you mentioned. I am sure they would know, probably fanatics about it.


----------



## Mad Max

All of those opamps that he listed are duals.


----------



## akinari-kun

Hey guys, I'm totally new to the world of opamps even though I've owned my Auzentech X-Meridian 7.1 2G for a year or two now. I thought I might as well upgrade the front channel opamps just to get the best out of my sound card.
   
  Based on what I've read, AD8066 or LME49860/49720 > LM4562?
   
*I'm having difficulty looking for places that sell opamps online, I cannot find a single site that sells any. Perhaps I'm looking in the wrong place? Could someone link me up to a place that sells opamps online?*
   
  I also can't seem to find the AD8066 anywhere except from a sketchy Chinese seller on eBay which I would like to avoid, although the seller claims it's "100% original." I'm not interested in soldering so I simply want to be able to take out and drop in a new opamp.
   
*Based on experience, AD8066, LME49860/49720, or any other newer offerings? *


----------



## razzz42

Quote: 





akinari-kun said:


> Hey guys, I'm totally new to the world of opamps even though I've owned my Auzentech X-Meridian 7.1 2G for a year or two now. I thought I might as well upgrade the front channel opamps just to get the best out of my sound card.
> 
> Based on what I've read, AD8066 or LME49860/49720 > LM4562?
> 
> ...


 
Cimarron Technology, Inc  is starting point for you, see the menu on the left.


----------



## SWIN

Quote: 





> Some dual channels chips that didn't require an adapter board.
> *NE5532N on the output makes no changes to the signal other than enhancements like turning up the volume across the entire range at once, very very clean sounding.


 
   Amazing as it is, the old NE5532 is the most well known, and used opamp for sound reproduction.
   
  There are not one human being on this planet, that have not heard music thru one of these devices....


----------



## jaddie

Quote: 





swin said:


> Amazing as it is, the old NE5532 is the most well known, and used opamp for sound reproduction.
> 
> There are not one human being on this planet, that have not heard music thru one of these devices....


 
  ...and it's single brother, the NE5534.  The noise-selected ones were darn good in a mic pre with a JE-115KE transformer just ahead of it.  Still are.


----------



## Tsuioku

What op amps would go well with Senns?  Currently have a C&C XO with an OPA627 but find it a little too warm and up front.
  I'll be using it with HD600s and need it in a DIP8 package @ 7V (Brown Dogged SOIC OK as well).
   
  Been looking around and the AD8620 seems to pop up the most.  Also considering the LT1364.


----------



## Gradius

Anyone tried the 994Enh-Ticha Dual Discrete Op Amp ?!
   
  How different they are from Bursons?   I use Bursons over a year now on my Xonar STX.
   
  Site:
  http://www.sonicimagerylabs.com/products/Model994DiscreteOpAmp-Ticha.html


----------



## Mad Max

Why don't you take the plunge and tell us?  
	

	
	
		
		

		
			




  Be sure to try it as is then try it again with a Russian K42-Y2 PIO capacitor connected across the power supply pins (pins 4 & 8 for a dual opamp, 4 & 7 for a single).


----------



## joyman

Hello all,
  I`ve been reading a lot about this but there`s something i want to confirm,
  i want to change the stock op-amp of the xonar dx,with dual LME49990 op-amps with this adapter: single to dual op-amp adapter so8 to so8 version http://cimarrontechnology.com/single-to-dualop-ampadapter-so8toso8versionpn031101a.aspx,
   
  can this be done?most of the LME49990 dual op-amps mods are for stx xonar,can dx fully support dual op-amps?
  does this mod needs any cap replacement for properly working?any overheat expected?
  i`m ready to go but need to get this clear.
  thanks a lot.


----------



## CommanerKeen

I've had my Essence STX for a while but never bothered with opamps but I've read they're a cheap way to upgrade/get better sound out of it.
  Any inputs on this?
  Thanks.


----------



## Mad Max

Quote: 





commanerkeen said:


> I've had my Essence STX for a while but never bothered with opamps but I've read they're a cheap way to upgrade/get better sound out of it.
> Any inputs on this?
> Thanks.


 
   
  There are threads on the matter in the computer forum.


----------



## Mad Max

Quote: 





joyman said:


> Hello all,
> I`ve been reading a lot about this but there`s something i want to confirm,
> i want to change the stock op-amp of the xonar dx,with dual LME49990 op-amps with this adapter: single to dual op-amp adapter so8 to so8 version http://cimarrontechnology.com/single-to-dualop-ampadapter-so8toso8versionpn031101a.aspx,
> 
> ...


 
   
  Here's a relevant thread: http://www.head-fi.org/t/339127/asus-xonar-dx-mods
  You want to replace the stock 5532?
   
  That is the right adapter.  I would recommend a lower bandwidth opamp instead of LME49990.  Try it if you want, just be careful when soldering to avoid ruining the little soic solder pads.
   
  I would instead try OPA602AU (2 on one adapter like the one that you linked), OPA2209, or OPA1642.  OPA827 could sound good in that circuit, who knows.  827 is a really terrific chip.


----------



## G.Trenchev

OPA1612 is my recommendation for @joyman.No adapters needed,since it's dual.


----------



## joyman

Quote: 





> OPA1612 is my recommendation for @joyman.No adapters needed,since it's dual.


 
   
  *i read good,reviews for opa1612,so i will go for it,is it any way/adaptor for convert DX so no always soldering is needed(SMT),like DG or STX,for future op-amp upgrade/swapping?
  *like music listening a lot and,but a lot of FPS surround-gaming too,any good cheap amplifier for modded DX?
  *actually using cheap AKG k44,and thinking upgrade too.
  thanks a lot.


----------



## Mad Max

K44 is nice.
   
  You could improvise with a socket first if you want to be able to roll.  Bend the pins slowly and carefully to line-up with the solder pads on the soundcard.  Tin the adapter pins and solder it in place.  Make sure that the notch on the socket faces the same direction as the 5532's - each 5532 has a dot next to pin 1 (pin 8 is across from pin 1), so the notch must face that direction where pins 1 & 8 are.  Then you can roll opamps as long as they are DIP opamps or are little SOIC chips soldered to SOIC-to-DIP adapters.


----------



## lawrywild

Tried the OPA827 on a dual adapter in my LDI+ and really didn't like it. Found it extremely bright.
   
  I have so many different opamps here to try but waiting for more adapters to arrive.


----------



## Mad Max

Quote: 





lawrywild said:


> Tried the OPA827 on a dual adapter in my LDI+ and really didn't like it. Found it extremely bright.
> 
> I have so many different opamps here to try but waiting for more adapters to arrive.


 
   
  Remember that they are not going to sound exactly the same in every circuit.
   

   
  Slower, lower bandwidth opamps are more likely to come close to acting like "drag-n-drop Lego bricks" than anything else.
  Generally, if the stock opamp is a slow one, then a high-speed opamp may not be the best idea, although sometimes changing/upgrading the psu bypass caps can help a lot.


----------



## lawrywild

Yup, understood. Don't really want to fiddle around with the amp too much, just going to roll all the opamps I can to find my favourite without doing any other cap replacements. They're all free samples so may as well.
   
  Most looking forward to trying the AD8597. LM4562 is my favourite atm (but OPA827 is the only other I've tried so far). Also looking forward to trying the tin can LME49710 (2x) to see if I prefer that to the LM4562.
   
  When biasing into Class A, do the resistors that are needed change depending on the opamp or the amp (would different opamps require different resistors in the same amp)?


----------



## joyman

Thanks, ordered the two adaptors and the op-amp,
  found in headfi forum ,capacitors can be added too:
http://www.head-fi.org/t/339127/asus-xonar-dx-mods
   
  *any sound quality gaining from this?
  *and maybe a crazy question can Xonar DX DAC be changed?
  *the front channel dac(DX) is a cs4398 czz and can be found at ebay http://www.ebay.com/itm/1-PIECE-IC-CIRRUS-TSSOP-CS4398-CZ-CS4398-CZZ-CS4398CZ-CS4398CZZ-/140709837665?pt=LH_DefaultDomain_0&hash=item20c2f5bb61
   
  **maybe can be replaced for a better one? maybe: http://www.ebay.com/itm/Burr-Brown-PCM1792A-192kHz-24-Bit-High-End-DAC-IC-PCM1792-/160811031513?pt=LH_DefaultDomain_0&hash=item2571159bd9
   
  *big thanks for helping and give important related info for noobs.


----------



## Mad Max

Quote: 





joyman said:


> Thanks, ordered the two adaptors and the op-amp,
> found in headfi forum ,capacitors can be added too:
> http://www.head-fi.org/t/339127/asus-xonar-dx-mods
> 
> ...


 
   
  Rolling DAC chips is highly *not* recommended.  You _will_ screw up the card.
   
  Just stick to the caps and opamps.


----------



## joyman

Thanks again,
  ok no DAC roll up.
  so what's the idea behind caps?lowering noise?


----------



## Mad Max

Bigger caps will condition the power a bit more, something like that.  Better power = better sound.
   
  Also, a power filter is another great idea.  Furman, Belkin, Monster, and more make power strips/centers/whatever with built-in filtration.  I use a Belkin one.  These have a greater impact on your entire system than opamp/cap rolling to any degree.


----------



## joyman

*can quartz/oscillator of the dx be changed,for something like this: http://www.ebay.com/itm/High-precision-TCXO-03ppm-24576000MHzGolden-AUDIO-/221208015762 ?
   
  waiting for caps and op-amp,thanks for share info.


----------



## Gradius

Quote: 





mad max said:


> Why don't you take the plunge and tell us?
> 
> 
> 
> ...


 
   
  I wish, but I'm moving in about 6 months, so can't do it now.


----------



## G.Trenchev

I just received AD8599 from Analog Devices.With my(now past) favorite OPA1612,I was really sceptical about this opamp,even lazy to place in adapter and try.
  I have to admit,I've never been so wrong.AD8599 is not the killer of details or clarity,but it sounds so lively and just right,it's awesome.Really,so alive and natural.Bass is powerful,but not overwhelming,just right,highs are just a little bit rolled off compared to other opamps I have,but very,very good.The sound stage is very realistic.It's like it's fine-tuned for live sound.I doubt now,if there's something as natural sounding out there.Highly recommended.
  My opamps : AD8599,AD8597,AD8397,OPA1612,OPA2132,LM4562,NE5532,JRC4558,JRC4556,TL082,OPA2134,OPA1642


----------



## lawrywild

Just finished rolling some opamps in my Little Dot I+ Hybrid (with Mullard M8100), here are my notes
   
*OPA827* (SOIC x2)
  - Fast and articulate
  - Severely lacking bass impact or depth
  - Bright/fatiguing
  - Excellent clarity
  - Ultra-detailed
  - Slightly artificial but relatively exciting sound
   
*LM4562* (DIP)
  - Good bass impact and quantity
  - Not as quick as OPA827
  - Good clarity but not OPA827 level
  - Realistic and natural sound
   
*AD8597* (SOIC x2)
  - Excellent sub-bass and extension
  - Good bass impact
  - Lacking top end sparkle and clarity
  - Not very fast
  - Non-fatigueing
  - Warm & musical but a bit too much so
  - Neither boring nor exciting
   
*LME49710HA* (TO-99 x2)
  - LM4562 with ever so slightly less bass
  - Basically the same as LM4562 as expected
   
*ADA4627-1BRZ* (SOIC x2)
  - Like AD8597 but brighter and more detailed with improved clarity
  - Less sub-bass and impact than AD8597 but still excellent
  - Above-average speed but not really enough to be called fast
  - Exciting, lively sound
   
*LME49990* (SOIC x2)
  - Decent bass but not close to AD8597 or ADA4627
  - Very neutral sound
  - Good sparkle
  - Neither dull nor exciting
   
*OPA1612* (SOIC)
  - Dull and flat (stopped listening here)
   
*OPA1641* (SOIC x2)
  - Good bass
  - Excellent clarity
  - Excellent separation
  - Sparkly but very sharp top end
  - Slightly sibilant
  - Detailed
   
   
   
  My favourite: *ADA4627-1BRZ* with the OPA1641 coming in second.
   
   
   
  Additional notes: OPA827 would be great if it had some more bass. AD8597 would be great if it had more clarity and speed.
   
   
  How does the AD797BRZ sound relative to the 4627-1BRZ? Seems like it could be a good candidate for me but hesitant to drop that cash on a pair of op-amps.


----------



## Mad Max

It might sound as good.  Opamps tend to vary from circuit to circuit.  You should get around to trying them all again with different psu bypassing schemes each.  It will change your opinion quite a bit on some of them.


----------



## lawrywild

Quote: 





mad max said:


> It might sound as good.  Opamps tend to vary from circuit to circuit.  You should get around to trying them all again with different psu bypassing schemes each.  It will change your opinion quite a bit on some of them.


 

 My goal was just to find the best sounding opamp in this circuit with these tubes. All the ones I've tried so far were free samples. The AD797 is very tempting though.. and I have one adapter pcb spare..


----------



## gibosi

Quote: 





lawrywild said:


> Just finished rolling some opamps in my Little Dot I+ Hybrid (with Mullard M8100), here are my notes


 
   
  I have the OPA2107 installed in my LD 1+ and quite like it. It can be obtained as a free sample from TI.


----------



## lawrywild

Quote:


gibosi said:


> I have the OPA2107 installed in my LD 1+ and quite like it. It can be obtained as a free sample from TI.


 

 That was one of the first I tried, before I received any of these. I didn't like it one bit, hence didn't bother with writing up impressions for it. From memory it was a little similar to the LME49990 sound but less sparkly. I also tried the OPA2132 at that time, and picked the LM4562 over both.


----------



## Mad Max

TL5580A sounds really nice in the Compass.  Similar to my pimped-out OPA827 so far, but a bit thinner and imaging isn't as sharp.  I like the low bass a bit better.
  Something about it reminds me of OPA602... I guess I need to roll chips again as I haven't bothered to in what feels like forever.


----------



## gibosi

Quote: 





lawrywild said:


> That was one of the first I tried, before I received any of these. I didn't like it one bit, hence didn't bother with writing up impressions for it. From memory it was a little similar to the LME49990 sound but less sparkly. I also tried the OPA2132 at that time, and picked the LM4562 over both.


 
   
  I think it is very commendable that you have gone to the trouble to audition and rank all these opamps. And even though I typically use tubes that are very different than the Mullard M8100, I think I just might try some of these opamps that you rank highly. Cheers.


----------



## leeperry

oh wow, mobos now come with a gold plated EMI shield on the Creative chip and a swappable dual opamp: http://www.legitreviews.com/article/2195/
   
  you even get a LM4562, goodness gracious


----------



## Gradius

Nice find there.  But after you get used w/ Bursons + high precision clock is just impossible to go back to OPA/LM/LME/AD/ADA/whatever toys.
   
  Perhaps only 994Enh-Ticha is on par with them.


----------



## Gradius

Cheap alternative to Bursons and 994Enh-Ticha:
  http://www.diyrecordingequipment.com/projects/sg-acoustics-soa-opamp/
   
  Need 2x of them, since is a simple version (not dual).


----------



## 00940

Quote: 





gradius said:


> Cheap alternative to Bursons and 994Enh-Ticha:
> http://www.diyrecordingequipment.com/projects/sg-acoustics-soa-opamp/
> 
> Need 2x of them, since is a simple version (not dual).


 
   
  might be worth to point out that Samuel Groner's opamp is not compatible with dip8 sockets. It follows the Jensen 990 layout used by most "pro" discrete opamps.


----------



## 00940

Quote: 





lawrywild said:


> Just finished rolling some opamps in my Little Dot I+ Hybrid (with Mullard M8100), here are my notes
> 
> *OPA827* (SOIC x2)
> - Fast and articulate
> ...


 
   
  One can safely bet that these "bright" opamps were oscillating.


----------



## razzz42

Interesting that a satisfying and acceptable signal is produced in a professional field to be sent along for processing to A/D converters and finally converted back D/A for human ear listening after all the mixing and manipulation has been accomplished. I see the chip(s) listed for mass mastering. So what headphones do these pros use? And what is inside their mixing boards? I suspect only a few even try to use this technology to its full potential. Many lack the talent to sound good and need audio technical enhancements or the clean mike signal will expose them for what they are i.e. lacking in talent or their flaws are their talent. Bob Dylan comes to mind as he could ruin any set of speaker with that scratchy voice of his, probably why a 'folk' song category was created for such performers. On the other end of the spectrum (think Alanis Morissette) there are those in-studio professionals that you never know their names except within the industry unless credited on CD inserts. The latest and greatest movie technology productions are always fun to listen to and watch because of constant improvements.
   
  Being a layman I digress to rambling on but as I posted elsewhere,  graphene is the next craze so get ready to unload your current stash of headphones and speakers.


----------



## lawrywild

Quote: 





00940 said:


> One can safely bet that these "bright" opamps were oscillating.


 

 Why is it safe to bet on that?


----------



## 00940

Quote: 





lawrywild said:


> Why is it safe to bet on that?


 
   
  Opamps of that quality don't sound sibilant or have a sharp top end. That's a clear sign of a problem in the frequency response and those opamps should be ruler flat at audio frequencies. Or it could be a sign of high order distortions. Considering the opamps are buffered by transistors, they shouldn't be so badly loaded that the thd would rise enough for it to matter. So there must be a problem in there.
   
  Especially considering how many people are reporting the opa827 to be similar in character to the opa627, which is anything but fatiguing.


----------



## leeperry

Quote: 





> Originally Posted by *00940* /img/forum/go_quote.gif
> 
> Especially considering how many people are reporting the opa827 to be similar in character to the opa627, which is anything but fatiguing.


 
   
  Have you really read many people claiming this? IME 627 sounds dark and tubey and 827 the complete opposite. There's a good reason why the latter is much cheaper than the former IMHO.


----------



## 00940

Yep, really. Make a search on diyaudio for a start.


----------



## razzz42

Off topic but nothing short of amazing.  George Massenburg Demonstrates the GML 8900 Dynamic Range Controller


----------



## Goobley

Hi all,
   
  I'm looking for some op amp advice for a new DIY project. My project will contain an opamp treated in a similar manner to an M^3 (i.e. class A biased 5mA driving an extremely high impedance load). I'm looking for +/-18V rail capability and sound-wise detailed but not bright, possibly mellow but overall detailed and neutral. It can be any type of input stage as I'm going to wrap it into a servo loop using either a precision or a chopper.
  Current favourites look to either LME49990 or OPA1611 but please recommend anything, there are so many that I just get lost, so I thought I'd ask the folks with experience.
   
  Cheers!


----------



## holland

Quote: 





> Originally Posted by *Goobley* /img/forum/go_quote.gif
> 
> I'm looking for +/-18V rail capability and sound-wise detailed but not bright, possibly mellow but overall detailed and neutral.


 
   
  OPA2604, and the LME49860.  I'm not sure about warm and neutral going together.


----------



## razzz42

Quote: 





goobley said:


> Hi all,
> 
> I'm looking for some op amp advice for a new DIY project. My project will contain an opamp treated in a similar manner to an M^3 (i.e. class A biased 5mA driving an extremely high impedance load). I'm looking for +/-18V rail capability and sound-wise detailed but not bright, possibly mellow but overall detailed and neutral. It can be any type of input stage as I'm going to wrap it into a servo loop using either a precision or a chopper.
> Current favourites look to either LME49990 or OPA1611 but please recommend anything, there are so many that I just get lost, so I thought I'd ask the folks with experience.
> ...


 
  LME 49990 seems to be a standard on some commercial sound adapters (cards and USB) and playback hardware like CD and DVD players. Good on clarity which helps separation, maybe favors the highs, voice range is excellent, lows good but are *not* going to absolutely pound. You could do a lot worse and not much better, IMHO. It's a single channel chip.


----------



## FritzS

Quote: 





holland said:


> OPA2604, and the LME49860.  I'm not sure about warm and neutral going together.


 
   
  Now I use OPA627 in my headphone amp, before I test some other OPA's 
  http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit/750
   
  OPA604 sounds a bit muddy in this design, with LME49710 - 'It's imagination from me or not - with LME49710 and K 701 I feel the trap is littleness sharper .........'
   
  This OPAs I test
   
  Railsplitter
  LM6171
   
  AMP
  LM6171
  AD843
  OPA602
  AD847
  LT1056
  LT1022 
  TLE2071
  OPA134
  OPA604
  LME49710
*OPA627*


----------



## Raito

Which op-amp would you recommend for Audio-Technica A900X headphones on Asus Xonar STX out of these:
   
  OPA2111
  OPA2132
  OPA2107
  LME49720NA
  LM6172
  LME49860NA
   
   
  I currently have two OPA2132s on I/V and one OPA2111 on buffer.
  Would it better to switch out the OPA2132s with OPA2107s?
  Any feedback will be appreciated!


----------



## Theta Alpha 1

Quote: 





razzz42 said:


> LME 49990 seems to be a standard on some commercial sound adapters (cards and USB) and playback hardware like CD and DVD players.


 
   
  Huh?  Please advise me of a single DVD player or stereo receiver (for speakers) which uses LME49990, I'd buy it in an instant!


----------



## razzz42

Quote: 





theta alpha 1 said:


> Huh?  Please advise me of a single DVD player or stereo receiver (for speakers) which uses LME49990, I'd buy it in an instant!


 
  Even though it is a relatively a new chip still finding its way into mainstream production, it can be found in hardware today. I read it listed inside a few sound adapters (USB, stand alone, etc.) but I am not going to do all your homework for you.
   
  Quote: 





> The quality of the CD 1 analog section is as important as its digital section. Designing an extremely accurate, stable, and linear digital section is a pointless exercise if the analog section does not have the very lowest possible noise to avoid degrading the purity of the decoded signal. It is for this reason that the CD 1 utilizes National Semiconductor LME49990 op amps exclusively in its analog section. The LME49990 is designed specifically for ultra-high end audio applications.


 
Parasound - Halo CD 1 - CD Player
   
  That's why a $100 sound card with swappable op-amp sockets is a big plus, you can try out the latest and greatest op-amps.


----------



## razzz42

Quote: 





raito said:


> Which op-amp would you recommend for Audio-Technica A900X headphones on Asus Xonar STX out of these:
> 
> OPA2111
> OPA2132
> ...


 
  My A900X favors the lows, not that the lows are natural but it does pound a bit, so you would want to use chips that would favor more high frequencies unless you are a complete bass freak. I'd stick LME49990MA in the I/V and then worry about fine tuning sounds to your liking with the one buffer socket.
   
  On Ebay some listings from China sell (1) LME49990MA on an adapter board for cheap but you need (2) LME49990MA on a (1) adapter board being that they are single channel. So, you need (2) adapter boards for the (2) I/V  sockets which would be utilizing (4) LME 49990MA between them.


----------



## Theta Alpha 1

Quote: 





razzz42 said:


> Quote:
> 
> 
> 
> ...


 
   
  Translation "There is no CD or DVD player using LME49990, I simply like talking."


----------



## razzz42

Quote: 





theta alpha 1 said:


> Translation "There is no CD or DVD player using LME49990, I simply like talking."


 
  You mean to say, "I can't afford a CD player that uses a LME49990 but I can dream."


----------



## DefQon

You can certainly roll in the LME's in a CD player if it tickles your fancy to do hear it.


----------



## Theta Alpha 1

Quote: 





razzz42 said:


> You mean to say, "I can't afford a CD player that uses a LME49990 but I can dream."


 
   
  The LME49990 costs $5, time-to-get-real-son.
   
  Quote: 





defqon said:


> You can certainly roll in the LME's in a CD player if it tickles your fancy to do hear it.


 
   
  I use a $1 coax cable from my CD player to my LME49990 x5 DAC.  You a trippin'.


----------



## razzz42

Quote: 





theta alpha 1 said:


> The LME49990 costs $5, time-to-get-real-son.
> 
> 
> I use a $1 coax cable from my CD player to my LME49990 x5 DAC.  You a trippin'.


 
  I didn't set the sucker's price for the example CD unit. Besides, if you ignore the price and bother to read the description of the Unit, it tells you how they went about designing and building the unit.
   
  Other than that, be my guest at slanting and spinning what I type, I could care less. I hope your cable bypasses completely your CD internals except I would think using a Blue Ray DVD player to read CDs would be a slight improvement.


----------



## zilch0md

Hey,

Has anyone tried using LME49990 as buffers, with LME49990 in I/V (in the PB2, for example)?

I'm currently using dummy buffers with the LME49990 because every opamp I try as a buffer with LME49990 in I/V only diminishes clarity, even if it does improve headroom/dynamics (as with the HA5004).

Thanks,

Mike


----------



## razzz42

Quote: 





zilch0md said:


> Hey,
> 
> Has anyone tried using LME49990 as buffers, with LME49990 in I/V (in the PB2, for example)?
> 
> ...


 
  This time around, was listening to Track Title : Lo Que Yo Más Quiero by Son By Four (2001)
   
  [size=x-small]Using[/size][size=x-small][size=x-small][size=x-small] AD-700 headphones[/size][/size] and my old[size=x-small] standard [size=x-small]P[/size][/size]rodigy HD2 (f[size=x-small][size=x-small]or testing),[/size]  with all empty socket[size=x-small]s[size=x-small], the [size=x-small]s[size=x-small]ou[size=x-small]nds [size=x-small]are distant. [size=x-small]With [size=x-small]the stock [size=x-small]OP[size=x-small]A 2604[size=x-small]AP [size=x-small]and buffer[size=x-small]/output empty, the [size=x-small]sound is t[size=x-small]inny in the highs,[size=x-small] favor[size=x-small]s some lows, not very re[size=x-small]al[size=x-small]istic (crap)[size=x-small]. Adding L49990MA in the [size=x-small]output, it enh[size=x-small]ance[size=x-small]s whatever the 2604 send[size=x-small]s it and brings [size=x-small][size=x-small]all the [/size]sounds fo[size=x-small]rwa[size=x-small]rd with a bit of d[size=x-small]et[size=x-small]ail[/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size] resulting [size=x-small]in[/size] higher qual[size=x-small]ity crap sounds.

 [size=x-small]Tr[size=x-small]ied the [size=x-small]AD797[size=x-small]BR[size=x-small] [size=x-small]with the ou[size=x-small]tput empt[size=x-small]y, favors the lows an[size=x-small]d mids[size=x-small], [size=x-small]some very h[size=x-small]igh end missing but clean detailed sounds throughout. Adding the L[size=x-small]49990M[size=x-small]A in the output, takes [size=x-small]and cl[size=x-small]arifies the entire ra[size=x-small]nge and br[size=x-small]ing all sound forw[size=x-small]ards.[size=x-small][size=x-small][size=x-small] Good clean fun.

 [size=x-small]Tried the NE5532N with the ou[size=x-small]tput emp[size=x-small]ty. Clear and clean with no [size=x-small]a[size=x-small]rti[size=x-small]fic[size=x-small]ial en[size=x-small]ha[size=x-small]ncements[size=x-small], [size=x-small]making [size=x-small]all sounds equal [size=x-small]acro[size=x-small]ss the ranges. Added the L49990[size=x-small]MA in the output[size=x-small] and resul[size=x-small]ted [size=x-small]in excellent sounds[size=x-small]. The entire range sound[size=x-small]ed true wi[size=x-small]th clear highlights[size=x-small], [/size] good separation[size=x-small] and [size=x-small]clarity. Highs were c[size=x-small]ri[size=x-small]sp[size=x-small].[size=x-small] [size=x-small]Lows and mids were t[size=x-small]rue. [size=x-small]Lows di[size=x-small]d no[size=x-small]t outright pound but sound clean[size=x-small] nonetheless.[/size][/size][/size][/size]

 [size=x-small]I could [size=x-small]eas[size=x-small]ily live with NE[size=x-small]5532N[size=x-small](s) and the L49990M[size=x-small]A i[size=x-small]n the output socket. Rival[size=x-small]s all my past configurations when considering al[size=x-small]l around [size=x-small]realistic sounds. Very [size=x-small]enjoyable.[/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size]

 The tried and true NE[size=x-small]55[size=x-small]32N are only a couple[size=x-small] bucks any[size=x-small]mo[size=x-small]re[size=x-small]. If you can only afford (1) ad[size=x-small]apter board with the [size=x-small]two L[size=x-small]49990[size=x-small]M[size=x-small]A [size=x-small]on it[size=x-small] then I would [size=x-small]us[size=x-small]e[/size] it in the outp[size=x-small]ut along with your favorite op-a[size=x-small]mps  in the [/size] [size=x-small]I/V sockets.

 [size=x-small]Your mileage[size=x-small] may vary.

 [size=x-small]Your welcome.[/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size][/size]
   
  (I will note that I couldn't get (3) adapted L49990MA to work on the card at once in all three sockets, not sure why but doesn't seem to be necessary.)


----------



## zilch0md

Thanks razzz42!
   
  I'll try them as buffers!
   
  Mike


----------



## nerdman

The 992Enh-Ticha and 994Enh-DUAL up to +/-24V, output drive100mA class-A...both dip8 footprint


----------



## Shini44

hello people, i've been asking a lot the same question around, and and i feel like many opamp users don't  know how to describe the opamp, all what does they say that this is better than that etc...



 i only went for the AD8610 with uha6s.mkii and it was nice , smooth, warm , been using UM Miracle back then, and went for the op627 + magic tube d1 + senn 650 before and the highs were cool although i heard that senn 650 don't have the best treble,  now i have Yulong D100 MKII which i didn't enjoy its amp section although i had the TH600 so  i am looking into getting M-stage and changing the opamp. 
  
  
  
 here is my final attempt ever before i lose the hope in opamp rolling, and go back to my old opamps. 

 " looking to change the opamp of after i get it M-Stage going to use it with TH600 which tend to have nice Treble, Highs and not the best mids

 for me the bass/treble comes 1st so i need to know what is the best option for me,

 OP627x2  or AD8610x2 or LME49710x2 

 i don't mind warm sig btw and i don't like the brightness,  i like the sound smooth and clean if possible but not to miss with the Treble/Bass/Highs ^^"


----------



## razzz42

How you describe the sound when an op-amp 'colors' or 'darkens' or 'veils' or cuts out the highs or cuts out the lows or sound 'flat' is very arbitrary from the listener's point of view.
  
 Best I can do is say it favors a certain range, like the highs or lows, then if it has clarity enough for good separation which leads to adequate staging.
  
 Try http://www.ebay.com/itm/1pcs-Dual-to-Mono-LME49990MA-replace-OPA2604-NE5532-TL072-LME49990MA-/181118392690?pt=LH_DefaultDomain_0&hash=item2a2b7f5972 one of the better starting points.
  
 A lot depends on the recording and phones/speakers you use, the amp then the DAC op-amps.


----------



## Foton

Hello, this is very interesting thread. Interesting and ...very long. I might miss something, but I have a question. Forgive me if someone already asked that question.Does it make any sense to judge op-amp sound quality in random circuit with op-amp rolling? As I understand correctly every circuit, that includes op-amps, needs careful implementation. Probably, there are some op-amps which will "tolerate" life in different environments. But, there are some, like AD 797, which will not work well in CMOY-style circuit. Should the proper judgment of sound quality be done by comparison of properly implemented op-amps with the circuits? 
 I just have doubts you can use any circuits with randomly selected op-amp and get great sound. And in reference to op-amps.... APEX makes great chips with great sound properties.


----------



## wakibaki

foton said:


> Does it make any sense to judge op-amp sound quality in random circuit with op-amp rolling?


 
  
 Ahhh. You're looking for an argument. You've come to the right place...
  





  
 w


----------



## Avro_Arrow

wakibaki said:


> Ahhh. You're looking for an argument. You've come to the right place...
> 
> 
> 
> ...


 
  
 I thought this was a cheese shop...


----------



## zilch0md

foton said:


> Hello, this is very interesting thread. Interesting and ...very long. I might miss something, but I have a question. Forgive me if someone already asked that question.Does it make any sense to judge op-amp sound quality in random circuit with op-amp rolling? As I understand correctly every circuit, that includes op-amps, needs careful implementation. Probably, there are some op-amps which will "tolerate" life in different environments. But, there are some, like AD 797, which will not work well in CMOY-style circuit. Should the proper judgment of sound quality be done by comparison of properly implemented op-amps with the circuits?
> I just have doubts you can use any circuits with randomly selected op-amp and get great sound. And in reference to op-amps.... APEX makes great chips with great sound properties.


 
  
 I think we would all agree with you Foton.  No component in any chain is allowed to sing solo.


----------



## Foton

Hello Wakibaki,
No argument was on my mind. There are to many threads around the net on different audio forums, about differences among capacitors, resistors, and volume pots, which turned violent. And I do not want to stear the pot. That was not my intention. My reply was more of a question and loud thinking than anything else. Like I said it is very interesting post and I will try to go through it this weekend. I am interested in test of different op-amps by myself. But, as I have noticed the criteria is to find great sounding op-amp. We can only do that within the circuit specifically designed for that part. Otherwise, we can dismiss really good chip based on incorrect implementation. I think it is very important for chips which we use for audio, but they were not designed for this purpose. example.... video chips.


----------



## Foton

sorry for double post...


----------



## SpudHarris

Anyone else tried the Muses 8820 (Bipolar) or 8920 (J-fet)? 

I was gifted a 8820 by a friend but only just got around to trying it in my P4. Very nice OpAmp, I've ordered a few of each to try in other stuff.


----------



## Sony Slave

zilch0md said:


> This time around, was listening to Track Title : Lo Que Yo Más Quiero by Son By Four (2001)
> 
> Using AD-700 headphones and my old standard Prodigy HD2 (for testing),  with all empty sockets, the sounds are distant. With the stock OPA 2604AP and buffer/output empty, the sound is tinny in the highs, favors some lows, not very realistic (crap). Adding L49990MA in the output, it enhances whatever the 2604 sends it and brings all the sounds forward with a bit of detail resulting in higher quality crap sounds.
> 
> ...


 
 Can you guys explain to me what I just read, and what razzz42 did? I ordered a little dot 1+ and I want to get the best sound out of it possible.
 When referring to OP amps, what is exactly is the buffer, output, and I/V?
  
 I will give you an examples from the quote of what I do not understand.
  
*"Tried the AD797BR with the output empty.... Adding the L49990MA in the output" *- What did he just do?
 And again, what is an *I/V socket*? 
 Photos/pictures would help a lot too.


----------



## gibosi

sony slave said:


> Can you guys explain to me what I just read, and what razzz42 did? I ordered a little dot 1+ and I want to get the best sound out of it possible.
> When referring to OP amps, what is exactly is the buffer, output, and I/V?
> 
> I will give you an examples from the quote of what I do not understand.
> ...


 
  
 To roll op amps in a Little Dot 1+, you do not have to worry about "buffers", "output", "I/V" and so forth. You simply pry out the old op amp and install the new one, assuming that you have purchased two of these single op amps pre-installed on a DIP8 adapter


----------



## Sony Slave

gibosi said:


> To roll op amps in a Little Dot 1+, you do not have to worry about "buffers", "output", "I/V" and so forth. You simply pry out the old op amp and install the new one, assuming that you have purchased two of these single op amps pre-installed on a DIP8 adapter


 
  
 I have the DIP8 adapter and OP amps, any idea on how to install them? I never opened my package of my op amps because of their sensitivity to static electricity.


----------



## gibosi

sony slave said:


> I have the DIP8 adapter and OP amps, any idea on how to install them? I never opened my package of my op amps because of their sensitivity to static electricity.


 
  
 Remove the original op amp. I just used a little screw driver, but if you are squeamish, you might want to purchase an op amp removal tool. Check the notch or mark on the op-amp adapter and make sure it lines up with the mark on the socket, and simply push it in. I am relatively inexperienced, having done this only a few times, but I have not found static electricity to be a problem. If others with more experience than I wish to add anything more, please feel free.


----------



## razzz42

I guess this is what you have, dead center is the replaceable op-amp, only one for you. Treat it like a changeable output/buffer op-amp which limits the selection of op-amps to buy and try.

 After you pry the op-amp out (and bend the legs, you can straighten them out and realign them with small pliers later) you will see the socket with a notch on one end (green arrow) as shown on my sound card with  2 empty sockets and 1 filled.

  

  

  


 Find the mark on your op-amp or adapter and plug it into the socket, aligned with the socket's mark (half moon) side. That's it. Never had a problem with static. You can buy a grounding strap that hooks to your wrist if necessary. Ebay has a cheap $5 op-amp removal tool, better than nothing. Take your time prying up and out the legs evenly but the op-amps are tough.


----------



## SpudHarris

spudharris said:


> Anyone else tried the Muses 8820 (Bipolar) or 8920 (J-fet)?
> 
> I was gifted a 8820 by a friend but only just got around to trying it in my P4. Very nice OpAmp, I've ordered a few of each to try in other stuff.




You guys have to give the 8820 an audition. I have had it in my Fi-quest for a week or so and I think it is fantastic. Balanced yet exciting, nothing is missing. I can't wait to try the 8920.....


----------



## ClieOS

If you like 8820, then you really ought to try MUSES02.


----------



## SpudHarris

Thanks ClieOS, I do indeed love the 8820. I have it in my MST Fi-Quest and am favouring it over my Icon HP8 with HD800's at the moment. Of course the Fi-Quest is a fine amp anyway but man it shines with the 8820. Ryuzoh (MST) gifted me with the 8820 when he sent my amp back after the last update. 

How does the 02 differ?


----------



## ClieOS

Think of 8820 with better texture, wider soundstage and overall higher resolution, and that will be how the 02 sounds like. 8920 on the other hand sounds more like the 01 step down. 01 will require higher voltage (+/-9V min) but it is usually better sounding than 02 in the same circuit, otherwise 02 has the advantage on lower voltage circuit. These are all seriously good sounding opamp.


----------



## gibosi

clieos said:


> Think of 8820 with better texture, wider soundstage and overall higher resolution, and that will be how the 02 sounds like. 8920 on the other hand sounds more like the 01 step down. 01 will require higher voltage (+/-9V min) but it is usually better sounding than 02 in the same circuit, otherwise 02 has the advantage on lower voltage circuit. These are all seriously good sounding opamp.


 
  
 I currently have a pair of LME49990 (DIP8 adapter) in my Little Dot 1+. Can I assume that I could also roll the 8820 and MUSES02? And if so, do you think that either or both of these would be an improvement over the LME49990?


----------



## ClieOS

gibosi said:


> I currently have a pair of LME49990 (DIP8 adapter) in my Little Dot 1+. Can I assume that I could also roll the 8820 and MUSES02? And if so, do you think that either or both of these would be an improvement over the LME49990?


 
  
 Well, LME49990 runs up to +/-18V while both 8820 and MUSES02 are only up to +/-16V. The only way to be sure is to measure the +V / -V on the LD1+'s DIP socket to make sure it is not over +/-16V. If the voltage is compatible, I'll suggest skipping the 8820 and go straight for the MUSES02. While 8820 is a good sounding opamp, I don't find it to be nearly as great as the 02.


----------



## gibosi

clieos said:


> Well, LME49990 runs up to +/-18V while both 8820 and MUSES02 are only up to +/-16V. The only way to be sure is to measure the +V / -V on the LD1+'s DIP socket to make sure it is not over +/-16V. If the voltage is compatible, I'll suggest skipping the 8820 and go straight for the MUSES02. While 8820 is a good sounding opamp, I don't find it to be nearly as great as the 02.


 
  
 Thanks for your very good advice and I will definitely check out the voltage. I really like the LME49990, but if the MUSES02 is as good or better, I am anxious to give it a try.
  
 Cheers


----------



## ClieOS

If it is +/-9 V and more, you might even want to try out MUSES01. If there is one opamp that I like a bit more than MUSES02, it will be the MUSES01.


----------



## razzz42

gibosi said:


> I currently have a pair of LME49990 (DIP8 adapter) in my Little Dot 1+. Can I assume that I could also roll the 8820 and MUSES02? And if so, do you think that either or both of these would be an improvement over the LME49990?


 
  
  


clieos said:


> Well, LME49990 runs up to +/-18V while both 8820 and MUSES02 are only up to +/-16V. The only way to be sure is to measure the +V / -V on the LD1+'s DIP socket to make sure it is not over +/-16V. If the voltage is compatible, I'll suggest skipping the 8820 and go straight for the MUSES02. While 8820 is a good sounding opamp, I don't find it to be nearly as great as the 02.


 
 Didn't answer answer the question about MUSES02 being an improvement over the 49990 or not...


----------



## ClieOS

razzz42 said:


> Didn't answer answer the question about MUSES02 being an improvement over the 49990 or not...


 
  
 That's because I never listen to a LME49990 before. I won't want to pretend I know how it'll compare.


----------



## SpudHarris

Well I'm a long time fan of the LME49990, it's a great OpAmp for sure. However, I am preferring the Muses 8820 at the moment so can only assume that the Muses02 would be even better. I'm tempted by the Muses02 but man they are expensive.


----------



## SpudHarris

I've given in to temptation and ordered a Muses 02. Last time I spent this much on an OpAmp it was OPA627SM :eek:


----------



## razzz42

clieos said:


> That's because I never listen to a LME49990 before. I won't want to pretend I know how it'll compare.


 
 Too bad you can't compare it with the MUSES...Anyone else have a real life experience with these opamps?


----------



## zilch0md

spudharris said:


> I've given in to temptation and ordered a Muses 02. Last time I spent this much on an OpAmp it was OPA627SM


 
  
 Yay!  I've been following and had thought about encouraging you to take the plunge, but decided not to tempt you.


----------



## psygeist

spudharris said:


> I've given in to temptation and ordered a Muses 02. Last time I spent this much on an OpAmp it was OPA627SM


 
 So, how was OPA627SM ?


----------



## SpudHarris

psygeist said:


> So, how was OPA627SM ?


 
  
 Hmmmm..... Not worth the extra over the AM and BP versions for sure. Fingers crossed regarding the 02 over the already brilliant 8820. Are you a fan of the OPA627? It tends to get overlooked a lot nowadays but still a good OpAmp IMO.


----------



## psygeist

spudharris said:


> Hmmmm..... Not worth the extra over the AM and BP versions for sure. Fingers crossed regarding the 02 over the already brilliant 8820. *Are you a fan of the OPA627*? It tends to get overlooked a lot nowadays but still a good OpAmp IMO.


 
 I am a newbie 

 Which other opamps are popular in this thread ?
  
 What's the difference between AU, AM, BP and SM ?


----------



## ClieOS

psygeist said:


> I am a newbie
> 
> Which other opamps are popular in this thread ?
> 
> What's the difference between AU, AM, BP and SM ?


 
  
 These kind of information can be easy found on the datasheet, usually in the spec or packaging section. Anyway, AU = SOIC, AM/BM/SM = TO-99, AP/BP = DIP. Also, B is has a tighter spec than A, and U, P and M also stands for different temperature tolerance. SM has been discontinued and replaced by BM.
  
 If you are interested in opamp in general, a good place to start is to learn to read datasheet. It can be quite useful in the long run.


----------



## psygeist

^^thanks for the heads up.
  
 Where do one buy MUSES1 or 2 ?


----------



## gibosi

psygeist said:


> ^^thanks for the heads up.
> 
> Where do one buy MUSES1 or 2 ?


 
  
 There are a number of vendors on eBay who carry these chips. As I haven't ordered one, I am not in a position to recommend any one over the other.


----------



## psygeist

gibosi said:


> There are a number of vendors on eBay who carry these chips. As I haven't ordered one, I am not in a position to recommend any one over the other.


 

 Wouldn't risk getting a fake.


----------



## zilch0md

spudharris said:


> I've given in to temptation and ordered a Muses 02. Last time I spent this much on an OpAmp it was OPA627SM


 
  
 When do you expect it to arrive, Nigel?


----------



## SpudHarris

psygeist said:


> ^^thanks for the heads up.
> 
> Where do one buy MUSES1 or 2 ?




Get them from Auditrak


----------



## psygeist

spudharris said:


> Get them from Auditrak


 

 thats the only option I see. Another one is wholesale.
  
 I noticed the price on their ebay store has additional shipping cost of $21 while on their website shipping cost is not mentioned.
  
 Will wait for your review before splurging.
  
 Which one are you gettin ?


----------



## SpudHarris

psygeist said:


> thats the only option I see. Another one is wholesale.
> 
> I noticed the price on their ebay store has additional shipping cost of $21 while on their website shipping cost is not mentioned.
> 
> ...




Price on website includes carriage. I've ordered Muses02 but I'm afraid it is going to work out expensive. Customs have got it so I will have 20% VAT + £13.50 handling fee :mad:

This had better set my ears alight for the price.


----------



## proid

Today i tried to swap the stock opamp 2068D of my O2 to the 1641 and the sound changed very slightly: a little darker, smoother sound, everything else is the same, may be bass is a little stronger, what a surprise )
 P/s: I clearly prefer the JRC 2068D to opa1641.


----------



## psygeist

OPA627 swapped with OPA2227 int output stage of the amplifier. Wow ! this sounds pretty good.


----------



## Libertad

I just purchased an HT Omega eClaro and found out that is has swappable op amps and was wondering what op amp is recommend for high current deliver on low ohm headphones. Im using some studio monitor headphones with them and love the sound but wanted alittle tamer highs and a little more of a warmer sound im happy with the bass as is ATM. Using JVC VICTOR MX10-Bs
	

	
	
		
		

		
			





 and stock JRC4580 DIP op amp. The card is feeding it 12v and i only have one socket it must be stereo and use DIP8 or DIP10 format. Im willing to consider a SOIC to DIP adapter configuration (im alright with a soldering gun)


----------



## razzz42

libertad said:


> I just purchased an HT Omega eClaro and found out that is has swappable op amps and was wondering what op amp is recommend for high current deliver on low ohm headphones. Im using some studio monitor headphones with them and love the sound but wanted alittle tamer highs and a little more of a warmer sound im happy with the bass as is ATM. Using JVC VICTOR MX10-Bs
> 
> 
> 
> ...


 
 Appears to be a headphone buffer output changeable socket. So the usual popular dual or adapted-to-dual suspects should work.
  
 Usual suspects means, LME varieties,  OPA2132P/OPA627 types, AD797 types and so on. I would just buy LME49990MA or from here on an adapter board from the far east somewhere (about $20us), slightly favors the lows but has good clarity and separation throughout all the ranges.  For a couple of dollars you could try a NE5535N but I don't think that is the sound you are looking for.
  
 [Waiting for the report back here on the MUSES02 sound quality. (MUSES01 favors highs MUSES02 favors lows or so they say)]


----------



## zilch0md

spudharris said:


> Price on website includes carriage. I've ordered Muses02 but I'm afraid it is going to work out expensive. Customs have got it so I will have 20% VAT + £13.50 handling fee
> 
> 
> 
> ...


 
  
 Good one!


----------



## SpudHarris

Still waiting.....


----------



## Libertad

razzz42 said:


> Appears to be a headphone buffer output changeable socket. So the usual popular dual or adapted-to-dual suspects should work.
> 
> Usual suspects means, LME varieties,  OPA2132P/OPA627 types, AD797 types and so on. I would just buy LME49990MA or from here on an adapter board from the far east somewhere (about $20us), slightly favors the lows but has good clarity and separation throughout all the ranges.  For a couple of dollars you could try a NE5535N but I don't think that is the sound you are looking for.
> 
> [Waiting for the report back here on the MUSES02 sound quality. (MUSES01 favors highs MUSES02 favors lows or so they say)]


 
 Thanks for the prompt reply ill definitely look into those. I am not versed into how they generally affect sound if you don't mind giving a simple break down on the OPA2132/627,AD797 and the NE5535N. It would be greatly appreciated. Im also waiting to see how the MUSE02 sounds and thanks again for your thoughts.


----------



## razzz42

libertad said:


> Thanks for the prompt reply ill definitely look into those. I am not versed into how they generally affect sound if you don't mind giving a simple break down on the OPA2132/627,AD797 and the NE5535N. It would be greatly appreciated. Im also waiting to see how the MUSE02 sounds and thanks again for your thoughts.


 
 It won't work like that. You have a different card than I do with a different chip set (Digital to Analogue Processor) plus I have (2 ) I/V swappable op amp sockets and (1) buffer output swappable. You have a CMI8788 audio processor where the specs look pretty good but I can't say I have heard it before unless it was a lesser model built into a motherboard. Stock buffer op amp for you is the 4580JRC. No idea when changing it out how responsive the results will be but it is cheaper than buying new headphones to get a different sound. Maybe your headphones will react better or worse than other models.
  
 Different model op amps can sound different even if the numbers are the same but the model lettering changes or there are sound differences between single and dual channel packages of the same chip scheme. Maybe available the same single channel chips made in a dual channel chip but guys here in the past will usually say there is a difference in sounds between them even though it's the same model type op amp. Note sometimes the sellers are not clear about their items.
  
 It's BBOPA627AU (Adds to much of its own coloring for me),  AD797BRZ or maybe the AD797BR (Was my go to chip for a few years but sounds a bit dark now compared to LME49990MA) of course the old NE5535N (which is the clearest, cleanest, most detailed and brings forward the entire sound range but in a cold way). LME49990MA works in the buffer (good clarity, separation and detailed bass). I didn't mention the LT1028CN8 which I am running in the buffer (Adds clarity and details favoring the highs and offsets the lows a bit from the LME49990MA that feed it from the I/V sockets, nice configuration). The LT1028CN8 being a single channel DIP, requires an adapter board with (2) side-by-side DIP sockets on top and DIP pins on the bottom. Make sure to have room to plug it in. It comes in a smaller/dual? package but I won't take the chance on a different sound coming from it.
  
 If you don't order the specific op amps called out then you might have a different opinion of what they sound like even if it is one letter or number off beside keeping straight the single and dual op amps with the necessary adapter boards.
  
 Me, I like open headphones and favor the highs so when I say dark, an op amp tends to have more bass. Coloring is an overall enhancement you can't remove or adjust away so you'd better like it. Some op amps bring forward the mids, highs or lows but you will discover that on your own terms. Warmth, echo, tinny, harsh, booming, flat, staging, depth, falloff, etc., you tell me.


----------



## wes1099

So where is the best place to buy op amps? I don't want to pay alot for shipping, and ebay has free shipping on most op amps, but im not sure if the ebay ones are fake.


----------



## SpudHarris

Where do you come from?
  
 In the UK I use Farnell. In the USA you have Mouser, Digikey etc.... Always buy from a trusted source, e-bay does have some genuine sellers but a lot of the expensive boutique opamps are fakes. Some of the manufactures also offer samples.


----------



## wes1099

I come from the lands of Northern Virginia in the USA


----------



## wes1099

And another question, what are the max specs a chip can have for this amp to be able to handle it safely. If you need more details on the amp, here is the instruction manual that has info about each individual part.


----------



## razzz42

wes1099 said:


> And another question, what are the max specs a chip can have for this amp to be able to handle it safely. If you need more details on the amp, here is the instruction manual that has info about each individual part.


 
 Your link to the .pdf has in it recommendation for op amps to try out....
  
 "...Once its all working you can experiment with the sound of other OPamps like
 OPA2132
 OPA2134
 OPA2227
 LM4562..."
  
 Seems the only limitation is shorter or longer battery life depending on which op amp you plugin.


----------



## chug

What is everyones verdicts on the chinese ebay opamps?
  
 http://www.ebay.com/itm/Top-Grade-Audio-OpAmp-OPA627SM-1-pcs-/270281884038
  
 http://stores.ebay.com/wkleung?_trksid=p2047675.l2563
  
 Etc.
  
  
 Also could anyone comment on whether the Audio GD opamps are a worthy upgrade to this...
  
 http://www.auzentech.com/site/products/opamp_627sm.php
  
 (I didn't pay that for it)


----------



## zilch0md

I can't speak for any others, but the U.S. ebay seller named "frugalphile" does awesome work and I've never had any problems ordering from him.
  
http://www.ebay.com/itm/2pcs-LME49990-DIP8-ADAPTERS-/190897296160?pt=US_Amplifier_Parts_Components&hash=item2c725d9320
  
 Mike


----------



## SpudHarris

x2 I'm with Mike, I've always had great experience with Frugalphile also.
  
 Sooooo Muses 02? Will be here today so will audition this evening. It had better be good, it has cost me nearly £80 with charges and VAT 
	

	
	
		
		

		
			





. That is the most I have ever paid for an opamp.


----------



## razzz42

chug said:


> What is everyones verdicts on the chinese ebay opamps?
> 
> http://www.ebay.com/itm/Top-Grade-Audio-OpAmp-OPA627SM-1-pcs-/270281884038
> 
> ...


 
  I rely on Ebay ratings and their customer comments a lot. As long as they have high ratings and high volumes sold then I don't have a problem with them. I have emailed sellers in China and HK (HK preferred) for clarification or other type opamps and adapters and they do get back to me usually within 24 hours even if it is in broken English, they understand what you want and what you are looking for i.e. matched set or same lot. Delivery times are usually no more than 2 weeks.
  
 Not sure about the metal cans even though I bought (2) BB K627 on an adapter board but it sounded 'hollow' to me. Might be good in some application like guitar pedals or whatever but not so much for playback.


----------



## razzz42

zilch0md said:


> I can't speak for any others, but the U.S. ebay seller named "frugalphile" does awesome work and I've never had any problems ordering from him.
> 
> http://www.ebay.com/itm/2pcs-LME49990-DIP8-ADAPTERS-/190897296160?pt=US_Amplifier_Parts_Components&hash=item2c725d9320
> 
> Mike


 
 I see the LME49990MA are getting cheaper as they become more popular, nice pricing from within the US. Nothing like competition. The site offers another set for even cheaper, not sure what the difference is.


----------



## psygeist

spudharris said:


> x2 I'm with Mike, I've always had great experience with Frugalphile also.
> 
> Sooooo Muses 02? Will be here today so will audition this evening. It had better be good, it has cost me nearly £80 with charges and VAT
> 
> ...


 

 waiting for the impressions. I am thinking of AD797BRZ or Muses 02.


----------



## psygeist

razzz42 said:


> I see the LME49990MA are getting cheaper as they become more popular, nice pricing from within the US. Nothing like competition. The site offers another set for even cheaper, not sure what the difference is.


 
 Cheaper one has 2 LME49990 on a single adapter.


----------



## SpudHarris

It has arrived, yay!

Man, look at the packaging, no wonder it didn't slip through customs. It even comes in its very own protective box, I think it is because it is far too superior to be mixing with the likes of my other lesser chips....

Well, initial impressions are that it is no ordinary OpAmp and certainly up there with the best (if not the best). I will have to spend more time listening to enable me to expand but it has an initial wow factor for sure. Kind of like HD, apart from the music it is pitch black. Take the customs and VAT out of the frame, I'd say its worth the money. If I can source them closer to home I will invest in a couple more but if I have to go through Audiotrak I will have to think hard as I have been stung badly this time and also previously with 8820's and 8920's I ordered.

More to come....


----------



## psygeist

How is it compared to its siblings ? 8820, 8920 
  
 I see you got buffer opamps. What are these ? To drive high impedance phones ? And where exactly is Muses 2 in your amp's circuit ?


----------



## Mad Max

chug said:


> What is everyones verdicts on the chinese ebay opamps?
> 
> http://www.ebay.com/itm/Top-Grade-Audio-OpAmp-OPA627SM-1-pcs-/270281884038
> 
> ...


 
  
 I'd recommend giving OPA602BP and TL5580 a go instead of those.
  
 Audio-gd's Sun HDAM can be really fun, but its MKT caps (little grey boxes on the sides of the device) need to be upgraded to something better, or you can get a bizarre, roller-coastery FR depending on the circuit that you blindly dump them into.  I've only tried 10uF 50V tantalums + 0.1uF 50V ceramics with great results.  Head and shoulders improvement in sound over the stock caps.  Russian K42-Y2 film capacitors are said to be awesome, too.  I think there's feedback on these in threads related to Audio-gd's Fun, Compass, and other past budget units that required an opamp in the DAC's output stage.


----------



## gibosi

spudharris said:


> It has arrived, yay!
> 
> Man, look at the packaging, no wonder it didn't slip through customs. It even comes in its very own protective box, I think it is because it is far too superior to be mixing with the likes of my other lesser chips....
> 
> ...


 
  
 My MUSES02 came today! 
  
 I ordered from an eBay vendor for $41.69 shipped to the US:
  
 http://www.ebay.com/itm/400418607953?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
  
 (With 67179 transactions, 99.7% Positive feedback, and a store with over 3000 ICs in stock, I felt fairly comfortable going with this vendor.)
  
 The packaging for my chip was much simpler, just a chip shoved into some foam inserted a sealed clear plastic pouch. My first impressions, installed into a Little Dot 1+ (replacing a pair of LME49990) with a US Amperex 6922/E88CC are similar. WoW! I really like this chip.


----------



## Libertad

anymore impressions on the MUSE02?


----------



## SoulSyde

libertad said:


> anymore impressions on the MUSE02?




Yes... Please.


----------



## zilch0md

Impress us!


----------



## gibosi

MUSES02
  
 Some context... First, I am rather old, so rather than golden ears, mine are more like rusty iron... lol My current amp is a Little Dot 1+, which is a hybrid, tubes and op amp. The 1+ came with a MC33078, and since then I have used an OPA2107, and most recently, an LME49990. I really like the LME49990, but like others, I have noticed that it can be rather cold and clinical when paired with some tubes. The MUSES02 adds a bit of mid-range presence, bringing vocals and instruments slightly more forward. As a result, the music seems to have more impact and presence and the overall presentation is more musical and toe tapping than the LME49990. And tubes that previously seemed a bit lifeless are now quite enjoyable. So for me, the MUSES02 is a keeper. Hope this is helpful. Cheers


----------



## zilch0md

That's an excellent review!  Thank you!  I'm especially pleased to read your comparison with the LME49990 (my current favorite).
  
 And now, to wait for Nigel's impression of the MUSES02...
  
 Thanks again,
  
 Mike


----------



## psygeist

I ordered both from same ebay seller. Let's see how it goes.


----------



## SoulSyde

I'm curious to know as well.  I'm thinking about trying the MUSES01 and 02 in my FiiO E12DIY I have coming soon.


----------



## SpudHarris

zilch0md said:


> That's an excellent review!  Thank you!  I'm especially pleased to read your comparison with the LME49990 (my current favorite).
> 
> And now, to wait for Nigel's impression of the MUSES02...
> 
> ...




Well I have finally closed the Fi-Quest with the Muses02 installed. The Fi-Q is an amazing amp and for evaluating OpAmps it has been invaluable but I'm calling time. I tend to favour tubes over OpAmps purely because the romantic analogue sound floats my boat. However, I am listening exclusively to the Fi-Q with the Muses02 at the moment, I have flicked back and forth between the Fi-Q and HP 8 with what are considered the best of the best 6SN7 tubes and the Fi-Q hits the sweet spot every night..... The sound is reminiscent of a high end tube amp, un fatiguing but still able to portray micro detail plus instruments and vocals with startling reality. It's a magical OpAmp and in my opinion worth the cost as I would easily spend twice or three times that amount on a set of boutique 6SN7 tubes heralding similar or quite possibly less levels of iaural enjoyment.

I would be very wary of buying from anywhere but Audiotrak though. There are a lot of cheaper decent sounding OpAmps out there crying out to be re-badged as Muses. Nice enough sounding for placebo to fill in the gaps.....


----------



## zilch0md

Great recommendation and warning, Nigel!  I was thinking the same thing as I noticed how there seems to be a lot of relatively inexpensive MUSES02 offered by sellers in China and Hong Kong, primarily.
  
 Thanks!
  
 Mike


----------



## gibosi

It would seem that folks believe I have a fake MUSES20.... Perhaps.... But if it is a fake, it is an incredibly good fake. Cheers.


----------



## zilch0md

Oh no!  I'm sorry!  I wasn't even thinking about you and others having already purchased MUSES02 from vendors other than Audiotrak.  
  
 We can't assume that any of those other vendors are actually fraudulent.  The odds are better that you're OK than not, but I just want to increase my odds by ordering from what is hopefully a "sure thing."
  
 Enjoy your purchase!  
	

	
	
		
		

		
			




  
 Mike


----------



## razzz42

Cheaper than buying  new headphones to get a different sound.


----------



## SoulSyde

gibosi said:


> It would seem that folks believe I have a fake MUSES20.... Perhaps....


 
  
 The thing that concerns me is that Audiotrak is a product of South Korea.  I do not believe that their manufacturing takes place in China, and the eBay listing you linked to is from China.


----------



## gibosi

soulsyde said:


> The thing that concerns me is that Audiotrak is a product of South Korea.  I do not believe that their manufacturing takes place in China, and the eBay listing you linked to is from China.


 
  
 It is a world market out there! For example, check out Mouser Electronics' (an authorized reseller) web page:
  
 http://www.mouser.com/ProductDetail/NJR/MUSES02/?qs=%2fha2pyFadujjt72El0q6OuEu%252bdt2pu9jgvOGE5AsfLc%3d
  
 Notice the pricing to the right:
  
        1:    $74.58    
      10:    $67.57    
      25:    $62.50    
      50:    $56.31    
      100:    $50.00    
      250:    $39.06    
      500:    Quote
  
 So you or I, or an eBay vendor in China or Korea, could buy 250, 500 or more of these, sell them for a little over $40, and make a profit. The vendor I chose specializes in ICs and carries over 3000 ICs in his eBay store. Further he has a positive feedback score of 67,691. Obviously, not a fly-by-night outfit....
  
 And the proof is in the pudding. I am pairing the MUSES02 with a USA-made Amperex 6922 / E88CC, among the best of the best, when it comes to micro detail, transparency and a startlingly realistic 3-D presentation. To my ears, the MUSES02 - Amperex pairing is significantly better than the LME49990 - Amperex pairing. So if my chip is a fake, it is an incredibly good fake.
  
 Cheers.


----------



## zilch0md

I like your arguments!   I might decide to save myself some money.


----------



## Libertad

Looks like its the MUSE02 then for me its seems like if paired with my sound card the sound would be pure euphoria.


----------



## Pluto2

There is this ultimate opamp shootout thread on dya and I couldnt tell the difference say between 741 and some other newer opamps @@"


----------



## Sony Slave

Just bookmarked the muse op amp.
 I'm gonna buy this thing in the future as well.


----------



## SpudHarris

The search is officially over, the Muses02 is the Holy Grail. When funds become available I will score another couple for the PB2. It's expensive but I honestly believe it's the end game OpAmp so worth it in my eyes....


----------



## Sony Slave

spudharris said:


> The search is officially over, the Muses02 is the Holy Grail. When funds become available I will score another couple for the PB2. It's expensive but I honestly believe it's the end game OpAmp so worth it in my eyes....


 
 Is there a difference between the Muses02 and Muses01?
 I'm thinking about buying a chip.


----------



## Sony Slave

I don't know if this was shared, but Muses actually talks about counterfeits on their website. 
  
http://semicon.njr.co.jp/eng/MUSES/precaution.html


----------



## zilch0md

@Sony Slave - Whoa!  Thanks for that!  I guess I'll spend the big bucks and get them from DigiKey (here in the States).  I need two (for my PB2).  
  
 The MUSES02's biggest advantage over the MUSES01, at least in terms of specifications, is that the ~02 offers 50mA per channel instead of 25mA from the ~01, and the ~02 can get by with a supply voltage of 3.5V vs. 9V. 
  
http://www.digikey.com/us/en/ph/njr/muses0102.html
  
@SpudHarris - Holy Grail?  What more need anyone with as many op-amps as you possess say about the MUSES02?   LOL   I'm convinced!
  
 Mike


----------



## zilch0md

Hmmm...  DigiKey won't let me order just two of them...  It says:  Minimum quantity not met; see price break.   
  
 It only quotes a price of $50, for 100 pieces!   I don't want to spend $5000.   
  
 Shopping elsewhere...
  
 Mouser is out of stock...
  
 Wow - This thing is made of unobtanium!  
  
 Mouser Electronics shows an 18-week back order and every other authorized supplier in the U.S. has a website that shows 0 results when I search for MUSES02.
  
 I guess I'm supposed to buy counterfeit because all the real ones are sold out!


----------



## psygeist

haha...funny thing is that the distribution channel of Muses opamps is terribly bad. Only a few retailers out there with exorbitant prices.


----------



## Libertad

looks like audiotrak still has them in stock


----------



## Sony Slave

zilch0md said:


> Hmmm...  DigiKey won't let me order just two of them...  It says:  Minimum quantity not met; see price break.
> 
> It only quotes a price of $50, for 100 pieces!   I don't want to spend $5000.
> 
> ...


 
 Like libertbad said. You can buy them here.
http://audiotrack.net/en/?mid=store&listStyle=list&document_srl=2196


----------



## SpudHarris

That's where I got mine from. Great to deal with but wish they'd use a different postage method so customs didn't have to get involved all the time. They are expensive enough without all the charges on top. Still worth it though


----------



## Sony Slave

How long did it take for the chip to come? 2 weeks?


----------



## SpudHarris

Would have been less than 2 weeks but customs held it for ages while invoices etc.... We're sent.

You may have better luck than me.

Either way you will love it I'm sure.....


----------



## Sony Slave

Even if it takes over 2 weeks, it'll be certainly worth it, it's gonna be the last OP amp I buy for a while, if ever again lol.


----------



## SoulSyde

sony slave said:


> Even if it takes over 2 weeks, it'll be certainly worth it, it's gonna be the last OP amp I buy for a while, if ever again lol.




I've been very pleased with the line of MUSES products. Enjoy!


----------



## zilch0md

sony slave said:


> Like libertbad said. You can buy them here.
> http://audiotrack.net/en/?mid=store&listStyle=list&document_srl=2196


 
  
 Thanks, but I'd rather buy them from a U.S. retailer - to avoid customs, etc.


----------



## gibosi

zilch0md said:


> Thanks, but I'd rather buy them from a U.S. retailer - to avoid customs, etc.


 
  
 For those of you in the US...  I understand that most consider purchasing from a Chinese eBay vendor, as I did, to be too risky, but I can say that my MUSES02 arrived in 7 to 10 days via first class mail with no hassles. And as someone who has purchased some 400 audio vacuum tubes from vendors in places such as Russia, Georgia, Ukraine, Moldova, the Czech Republic, as well as Hong Kong and China, it has been almost hassle-free. The only "hassle" is that some vendors ship via registered mail, and if I am not home when the mail carrier stops by to get my signature, I have to go to the post office the next day to pick it up. 
  
 Cheers


----------



## DefQon

Man got so many questions don't know where to start.

Ok what is the purpose of having 2-6 dual or single opamps in the output stage of some vintage high end CDP's?

What is the best opamp for the I/V converter section of CDP's?

Although discontinued what can be a single suitable drop in replacement of a MC34072 opamp?

A dac which uses 4 LME47920's and 2 LME49710's can take dual or single OPA627's?

To be edited


----------



## psygeist

My parcel reached the main post office. May be able to try out Muses 1 and 2 this morning.


----------



## SoulSyde

Could someone please suggest a quality dual channel op amp to replace the OPA2134 in my FiiO A1?  I'm looking for a slightly brighter and more lively presentation to add a little more sparkle to my Energy C-100 bookshelf speakers.
  
 Thanks!


----------



## zilch0md

soulsyde said:


> Could someone please suggest a quality dual channel op amp to replace the OPA2134 in my FiiO A1?  I'm looking for a slightly brighter and more lively presentation to add a little more sparkle to my Energy C-100 bookshelf speakers.
> 
> Thanks!


 
  
 What do you think, guys?  
  
 OPA1612?


----------



## DefQon

LME49990 or the 49720/10's.


----------



## zilch0md

I almost said LME49990, but the OPA1612 is a little brighter, if that's what he's looking for...


----------



## SoulSyde

zilch0md said:


> I almost said LME49990, but the OPA1612 is a little brighter, if that's what he's looking for...



 
I'm looking to add a subwoofer to my setup so bright is what I'm looking for.  Thanks for the recommendations guys.


----------



## DefQon

Can someone please answer my previous post if they can? Mad Max where are you?


----------



## zilch0md

defqon said:


> Man got so many questions don't know where to start.
> 
> 1) Ok what is the purpose of having 2-6 dual or single opamps in the output stage of some vintage high end CDP's?
> 
> ...




My understanding is limited, so I invite others to chime in, but here goes:

1) The Output stage can be thought of as your current gain stage, so op-amps with higher current outputs are preferable in the output stage and stacking them in parallel yields even more current. You can find current output specs in an opamp's data sheet (PDF).

2) The input voltage gain section is where you need to exercise more finesse in selecting an op-amp - going for the sound signature you prefer. Try the LME49990 or the more expensive MUSES02, but understand that you should really try to learn what the current opamp's specs say about supply voltage, for example. If the current opamp is designed for a 3 to 5V supply, there's no point in trying an op-amp that requires a 9 to 18V supply. It's actually quite risky just plugging in anything that fits the socket. Try to learn as much as you can about what you are replacing.

3) I don't know...

4) Find the data sheets for the LME47920 and LME49710 to confirm this, but I believe the -20 is a dual and the -10 is a single.

Mike


----------



## DefQon

zilch0md said:


> My understanding is limited, so I invite others to chime in, but here goes:
> 
> 1) The Output stage can be thought of as your current gain stage, so op-amps with higher current outputs are preferable in the output stage and stacking them in parallel yields even more current. You can find current output specs in an opamp's data sheet (PDF).
> 
> ...


 
  
 Thanks for that Mike, appreciate the effort in your response. 
  
 I've measured the points in my CDP where I've taken out the existing BB OPA2132 opamps and it's around 14vdc one of the points and another 5v. I think throwing in a OPA627 should be ok.
  
 So from what I understand the I/V converter stage needs a good detail, revealing or neutral opamp, where as the opamps for the analog outputs in the output stage can be rolled for whatever flavor in sound you want?
  
 I've always confused dual and single opamps, by single I'm assuming single mono like a SOIC8 627? And dual is stereo is in other words 2 mono opamps in a single DIP8 package?


----------



## psygeist

Muses 01 is huge in soundstage and a lot more neutral compared to 02. I am liking it a lot more. Whole day I am listening to same collection and rediscovering everything on a whole new level.
  
 Will try to spend more time listening to Muses 02 but Muses 01 has the WOW factor I was looking for.


----------



## zilch0md

I can tell from my experiments with the iBasso PB2 that buffers (opamps in the output stage) certainly influence the sound signature, just as the I/V opamps do, but you want to concentrate on selecting opamps that put out a lot of mA (output current spec) here in the output stage, where the output current spec doesn't matter so much in the input voltage gain stage - where you can play with a wider selection of opamps to get the sound you want (without concern for their output current specs).

This is my understanding, at least, and I remain ever-ready to be corrected if someone wants to educate me.


----------



## jcx

defqon said:


> Man got so many questions don't know where to start.
> 
> Ok what is the purpose of having 2-6 dual or single opamps in the output stage of some vintage high end CDP's?
> 
> ...


 
  
 really old CDP may have complicated, high order 20 kHz analog active filters for the "brick wall" reconstruction filter - needed because of low/no oversampling in the early DAC chips - before today's higher OS ratios, digital filtering
  
 some may even have the RedBook deemphasis shelving filter in a op amp active filter
  
  
 DAC I/V choice has many "moving parts", "best" is an engineering judgment - intelligent rolling requires taking into consideration at least  DAC chip, feedback, power supply, high frequency layout quality...
  
  
 the only MC34072 "discontinued" I see are the old Pb plated parts - helps to know ON-Semi is the continuation of Motorola's analog  business and then you can see the product status, read the datasheet
  
 as a 4.5 MHz bjt op amp it boasts jfet input level slew rate and a quasicomplementary output stage that swings a bit closer to the supply rails than some others of its class/generation, also has the somewhat unusually high 44 Vmax supply - check the ps V on the board before choosing replacements
  
 but its input V noise is horrible so any jfet input op amp beats there while matching the slew rate, more modern outputs in "isolated" semi processes with good npn/pnp speed matching are easily better today if designed for low output distortion
  
 "better" modern chips shouldn't be hard to find on all specs - just don't go crazy on GBW - I wouldn't recommend more than double the speed without an oscilloscope fast enough to see any possible oscillations in the replacement


----------



## NCSUZoSo

Can you guys check my understanding of my Op-Amps and Adapters with the orientation on the PCB socket (Creative ZXR)?
  
 This is how I think it is supposed to go:
  
 http://cdn.overclock.net/3/36/900x900px-LL-3645296d_ZXR-Op-Amps-Decoded.jpeg
  
 (*Red = Pin 1 Location
 Green = TO-99 Key Orientation)*
  
 So for a normal Op-Amp the circle or indention goes towards the half moon/cut out of the PCB socket. For the TO-99 style like the OPA627SM and the adapters above the metal tab will go on the same side as the half moon/cut out PCB socket due to the tab key being in the same direction as the pin 1 white circle indication.  The MUSES01 will obviously go with the indention towards the cut-out end of the PCB socket.
  
 Besides the MUSES01 and 2x OPA627SM I am also using a Dual DIP8 to Single DIP8 adapter for the rear channel (or maybe the center/sub depending on the MUSES01 performance) so that I can utilize the LM49710's for the rears.  So my total 5.1 setup will go like this.
  
 Fronts: OPA627SM
 Center/Sub: MUSES01
 Rears: 2x LM49710's
  
 Can I get verification I have the above right on  the orientation and any opinions?  BTW I did not pay outrageous prices from Digikey or Mouser's, I used Ebay and I am waiting the 10 or so days for this stuff to arrive.  Prices were as follows (this includes shipping):
  
 MUSES01: $32.99
 OPA627SM (pair): $28.60
 Adapters: ~$17.00 (I went with high quality 2oz copper adapters) 
 -----------------------------------------
 Total: $78.59, around the price of a single MUSES01 from DigiKey
  
 Here are the adapters I went with, Single DIP8 to Dual DIP8: http://www.ebay.com/itm/170921295768?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
 TO-99 to DIP8 (2x): http://www.ebay.com/itm/181236559628?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649


----------



## psygeist

I found OPA627 to be more thick sounding and colored compared to MUSES 01.
  
 Right now main amp section uses MUSES 01 and output stage has AD8620. OPA627 takes up the EQ stage which can be bypassed.
  
 So far, the best combination I have heard. MUSES 02 goes into the bag.
  
 Thinking of ordering 2 more MUSES 01 from same ebay seller just in case the price increases.
  
 @ gibosi, thanks for the ebay link.


----------



## FritzS

I search on MUSES homepage an found only dual OPAs
 http://semicon.njr.co.jp/eng/MUSES/
  
 MUSES01
 http://semicon.njr.co.jp/eng/MUSES/MUSES01.html
 http://semicon.njr.co.jp/eng/PDF/MUSES01_E.pdf
  
 MUSES02
 http://semicon.njr.co.jp/eng/MUSES/MUSES02.html
 http://semicon.njr.co.jp/eng/PDF/MUSES02_E.pdf
  
 Whats about this new both?
 MUSES8820
 http://semicon.njr.co.jp/eng/MUSES/MUSES8820.html
 http://semicon.njr.co.jp/eng/PDF/MUSES8820_E.pdf
  
 MUSES8920
 http://semicon.njr.co.jp/eng/MUSES/MUSES8920.html
 http://semicon.njr.co.jp/eng/PDF/MUSES8920_E.pdf
  
 For some I need only single OPAs.


----------



## NCSUZoSo

As far as I know the MUSE series of Op-Amps are only in dual offerings, I could be wrong, but I looked at a lot of them.  The easiest way is to just check the schematic on them (offered in any of the spec sheets) and then it's obvious.
  
  
 I have a question for anyone who may know (Rob?) on the Creative ZXR which slot is which channel.  They are labeled J1-J4 and I assumed J3 is Center/Sub and from what I have listened to I think I was right.  However to get some confirmation would tell me if I am getting a placebo effect or not.


----------



## gibosi

psygeist said:


> Thinking of ordering 2 more MUSES 01 from same ebay seller just in case the price increases.
> 
> @ gibosi, thanks for the ebay link.


 
  
 I have just heard back from Little Dot that the MUSES01 can be used in my 1+. so I am going to get one too. The MUSES02 sounds crazy good so I am very excited to try the MUSES01. Cheers.


----------



## NCSUZoSo

Creative Explained ZXR PCB Layout:
  
 http://www4.picturepush.com/photo/a/13880257/img/Computers/Creative-Explained-ZXR-PCB-Layout.jpg
  
 "Please note, there is not center, and about front and rear, are the big cylinder"
  
 Have to love guys answering questions for tech support that can't speak fluent English.


----------



## spydur

Hey guys can you give me some recommendations and possible links to some op-amps that will work on an Audio GD Fun rev.A. I have the Earth and Moon, currently running moon. I am using the fun with the Sennheiser HD650. I am looking for a bit more bass down low and maybe a little more punch overall?
 Thx!


----------



## spydur

anyone out there?


----------



## Mp0wer

defqon said:


> LME49990 or the 49720/10's.


 
  
 I have both and can't really tell the difference, there very close in sound
  
 Actually the LME49990 are a little bit brighter and open


----------



## UnknownAX

I'd want to try a ad823 in my amp. The amp is similar to a cha47 and has two dual opamps, buffer and output. The output is a jrc4556 and I'd like to use a ad823 as the buffer. The amp is unity-gain. Should I expect any complications?


----------



## UnknownAX

unknownax said:


> I'd want to try a ad823 in my amp. The amp is similar to a cha47 and has two dual opamps, buffer and output. The output is a jrc4556 and I'd like to use a ad823 as the buffer. The amp is unity-gain. Should I expect any complications?


 
 Can anyone tell me if it'd work? It's the AD823ar version to be exact. AD712 or OPA2604 would also be options, although the OPA2604 seems to be similar to the 2134, which is currently in use.
 (The chip that you use to adjust the gain of the amp and that feeds the other opamp is the "main" chip, right? The other unity gain chip is the buffer?)


----------



## Oversemper

Good Day, Everybody!
 I've got a just released dedicated USB DAC/AMP "DR.DAC 3". Here is a link to detailed specs: http://sdrv.ms/1guxEIo
 I mainly want to use it as a DAC with line-outs going to a headphone amp (and/or a pre-amp for a speaks amp).
 It got a PCM1794 D/A and a triple op-amp circuit with a pair of NE5532 in I/V section, MUSES8920D in sum. section and the same MUSES8920D in line-out section.
 So, what I want is to get the best of the PCM1794-to-line-outs path in terms of sound details and neutrality (pass on the sound as it is). And I don't wanna use soldering stuff like soldering mono-soic8-opams onto dual dip-8 adapter. So, I'd like to use only dual-channel-dip8 opams.
 Thanks for any suggestions!


----------



## SWIN

Those contemplating to buy one of the New Japan Radio Co, Ltd MUSES IC´s, please note that the local price in Japan is about as follows.
  
 MUSES 01    3500:- JPY
  
 MUSES 02    3400:- JPY
  
 MUSES 8920  480:- JPY
  
 MUSES 8820  400:-  JPY
  
 All in DIP8.
  
 Thu some local Japanese forums, I was lucky enough to find a supplier, that accepted my order.
  
 Postage to my country was 1500:- JPY, delivered in 5 days.
  
 Also note, that local tax and customs may be added.
  
  
  
 /SWIN


----------



## psygeist

^^Good pricing 
  
  
 Let us know which one you prefer more.


----------



## gibosi

I received the MUSES 01 a few days ago. For some time, I have been running the MUSES 02 in a hybrid headphone amp (Little Dot 1+).
  
 The 01's stage does seem a bit wider, but this is not to say that the stage on the 02 is narrow. The 01 has a bit more grain. It is not as fluid and liquid as the 02. The 01 has less bass presence than the 02, With less bass, the mids and treble are relatively brighter. And the 02, with more bass, is relatively blacker and darker.
  
 In the end, there is really nothing to criticize about either of these chips, I think it simply comes down to the synergy of all the elements in a given system and one's preferred sound signature..
  
 I have put the 02 back in to stay.


----------



## zilch0md

Thanks for your impressions, gibosi!


----------



## psygeist

Exactly why I like MUSES 01. Agree that it has to do with overall synergy too.
  
 Do you recommend any track where you noticed grain ?


----------



## gibosi

It really does come down to synergy. My default tube, a Holland-made E188CC, has a glorious wet mid range with great liquidity and flow. Putting the 01 in, there was less flow and the mid range was a bit drier. Putting the 02 back in, the flow came back and mid range was glorious again. Some example tracks:  James Blake's Overgrown album - 'Overgrown', Robert Glasper's Black Radio 2 album - 'Calls', and David Gray's White Ladder album - 'Please Forgive Me'.
  
 Again, it really does come down to synergy, and given my ears and gear, the 02 and the E188CC are a match made in heaven.


----------



## NCSUZoSo

Guys what would be the cause of static coming from one channel using my Creative ZXR w/ OPA627SMs and a MUSES01?  I noticed when I was trying to fit a Dual DIP8 to Single that I scratched the outer surface of one of the near by capacitors decently.  More than a scratch, more like a light gouge.  I checked continuity from the leads of the OPA627SMs and the other two Opamps to their solder points on the back the of the PCB and everything was good there.
  
 I first tried to install the OPA627SMs on their own adapter, but it was too tall so I put them in the more common socket adapters.  I'm wondering if I could have gotten one of the Opamps too hot between soldering -> desoldering -> soldering.  Also when you touch one of the leads (either lead 2 or 7 I believe), is it supposed to have continuity with the metal cap?  I just now noticed this static because I used headphones for the first time in a long time last night and on multiple source files I got static out of the right channel.  I guess I just didn't notice it when running 5.1 due to all the other speakers.
  
 The odd thing to me is when there is nothing being played there is no white noise or anything coming from the channel, I figured if there was a problem like that it would always be there.  If a damaged cap could do this, I can easily replace that cap.
  
 The bad part is I continued my upgrade and I have 2x ADA4627-1BRZs converted to a dual op amp-DIP8 on the way here...  I'm going to feel pretty stupid if I can't solve this and I have more component upgrades on the way.
  
  
 Even when I isolate the right speaker I can not hear any distortion or static coming from it, is it possible there is something wrong that is only picked up through headphones?


----------



## razzz42

My guess is you didn't cleanup the flux after re-soldering with either flux remover or some alcohol with a fine brush or light scraping with a dental tool. Even then sometimes a silicone spray is needed to preventing tracking crossover. Next guess you fried the chip. Next guess, would be a bad connection: adapter pins, headphone leads, any possible bare leads in use or not in use.
  
 You should be able to find the problem by checking connections or backtracking, trying different headphones, trying good known opamps. I can't speak to a gouged capacitor but if it is not leaking it should be good.


----------



## NCSUZoSo

I think the chip itself is damaged, which doesn't upset me too much because the OPA627 isn't a very expensive op-amp these days.  I was thinking about replacing them right after buying them, how does the LME4990 perform in comparison?  Is it as colored as the OPA627SM or is it more transparent?  Is it better or worse in the THD department during actual usage, basically I know someone must own both of these and can compare them since they are so common.
  
 Is there another single operational Op-Amp I should be considering besides these (OPA627 and LME49990) for my Creative ZXR?  In the rear dual DIP8 slots I have a MUSES01 and 2x ADA4627-1BRZs converted to a dual op amp-DIP8.  So anyone have any suggestions for replacing the most likely burnt OPA627SMs?
  
 My only question about the issue I am having is why is there only any issue at all when using headphones?  I have isolated my front Polk Audio 45B to the right speaker only and there is absolutely no noise, not even when playing Blu-Ray audio like the Pink Floyd Immersion material.  So I don't understand how that is possible for only the heaphones to have an issue.  When I noticed the issue I was using a cheap Creative "Tactic 3D Alpha" headset, however since then I have also experienced this with my Technics RP-DJ1205s.
  
 Maybe I should get two more ADA4627-1BRZ and put them in the front?


----------



## Audiofanboy

First time on this thread, please treat me nicely! 
	

	
	
		
		

		
			




  
 I just read about the positive returns on the MUSES opamps. I'm kind of curious as to what position most of you tried these in (I/V, buffer...) since I can think of at least 5 sockets where I could (re-)upgrade chips in all my gear...
  
 I used to roll opamps pretty often a year or two ago, until I settled for whatever worked best on each piece of equipment I own. Namely, 4 x AD797BR on my DAC outputs, and 6 x OPA627AU in my iBasso D10 (2 for I/V stage & 4 for buffer); I had also settled for 2 x OP637BP on my Auzentech sound card before I sold it, since the circuit allowed non-unity gain opamps and that one gave me the best sound (though retrospectively, 2 x AD797 would have been just as good if not better).
  
 So, I could be interested in, say, the MUSES02 in both my DAC outputs, and in either position in the D10, depending on feedback here. Any suggestions?
  
 Any direct comparisons with the AD797 too? Seeing as it's kind of my go-to opamp when the circuits allow for it to work well (not oscillate or whatnot).


----------



## razzz42

I used AD797 for a couple years then switched to the MA49990 as it can go in any position with its clarity across the range, maybe a slight lack of base. OPA627 was always to colored for me, colored the entire range. Have a MUSES01 in the mail to try in the output socket to see what I think of it. Preferred the staging and highs from opinions vs the 02 warmth and bass reviews.
  
 Running MA49990 in the I/V sockets and LT1028ACN8 for output (both chips need their own adapters) on a Prodigy *HD2* DE card.


----------



## NCSUZoSo

Ok, well I was right about the receiver not outputting any noise on the right channel like the sound card does when I plug into the little volume control module with headphone hook ups.  The difference to the sound card is the headphone amplifiers on the card are not kicking on, so that is playing some role in creating the static.  This makes no sense to me if it was related to anything I did with the Opamps, because the on-card headphone amp shouldn't be affected by changing them (in how it works).  This really is no issue since I can just plug into my Yamaha RX-V863 to use my headphones, but I would still like to know why the headphone amp is creating noise in the signal when it kicks on.


----------



## rhead

I just got some LF411ACN from TI, can't wait to test em out.


----------



## Audiofanboy

Well, I just bought both the MUSES02 and the MUSES01 to try them out. I just couldn't _miss out_ on all this opamp fun lol...
  
 Anyway, will report back when I do get them.


----------



## NCSUZoSo

I'm happy with my MUSES01, I put it in alone just to see what affect it would have and you could tell there was better clarity and bass with it installed.
  
 I'm interested to see how this final piece to my setup will play along with everything else, the 2x ADA4627-1BRZs converted to a dual op amp-DIP8.
  
 I'll be running:
  
 2x OPA627SM
 1x MUSES01
 1x ADA4627-1BRZs (duals)


----------



## NCSUZoSo

Well I fixed the problem with my right channel issue when using the on-board headphone amp on the ZXR.
  
 I pulled the OPA627s and put in AD8597s in their place and now everything works and sounds great.  It seems the 8597s have more clarity over the 627s, which is what I sort of expected due to all the info on the 627s being highly colored compared to other Op-amps. I must have gotten one of the OPA627s too hot between soldering -> desoldering -> soldering again and damaged the circuit.  The AD8597s came pre-soldered onto a Brown Dog SOIC 8 to DIP8 adapter and I just had to solder on the pin headers.  One thing great about these is they are no taller than the capacitors on the board so I will be able to reinstall the EMI shield.  I'll be sure to show yall pics once my final Op-amp arrives (1x ADA4627-1BRZs (duals)).


----------



## razzz42

ncsuzoso said:


> Well I fixed the problem with my right channel issue when using the on-board headphone amp on the ZXR.
> 
> I pulled the OPA627s and put in AD8597s in their place and now everything works and sounds great.  It seems the 8597s have more clarity over the 627s, which is what I sort of expected due to all the info on the 627s being highly colored compared to other Op-amps. I must have gotten one of the OPA627s too hot between soldering -> desoldering -> soldering again and damaged the circuit.  The AD8597s came pre-soldered onto a Brown Dog SOIC 8 to DIP8 adapter and I just had to solder on the pin headers.  One thing great about these is they are no taller than the capacitors on the board so I will be able to reinstall the EMI shield.  I'll be sure to show yall pics once my final Op-amp arrives (1x ADA4627-1BRZs (duals)).


 
 I would tell you to recheck any solder flux overflows on the adapter board's traces and clean it off but the 627 is not worth the trouble in my opinion.


----------



## highfell

audiofanboy said:


> Well, I just bought both the MUSES02 and the MUSES01 to try them out. I just couldn't _miss out_ on all this opamp fun lol...
> 
> Anyway, will report back when I do get them.




Have you received them yet? What is your review?


----------



## Audiofanboy

highfell said:


> Have you received them yet? What is your review?


 
  
 Nope.
  
 I'm not even sure whether or not China sent them yet, so reviews might have to wait a while...


----------



## razzz42

MUSES01 arrived from China but I am giving it about 40 hours of break in before saying anything about it. Sounded neutral to begin with but the lows are showing up now and waiting for some mid to high areas to fill in. Using  it in the output socket to headphones.


----------



## NCSUZoSo

"Break in" is a mechanical term that refers to things like speakers or anything using a suspension system like phono cartridges for example.  The term you _would_ use for opamps is burn in, but many people (including myself) believe it is more your brain burning in when it comes to SS electronics.  Now when you talk about about tubes or even capacitors, there is some truth to it (it can actually be proven when you measure the output of the circuit), now an Opamp "breaking/burning in" that is the same as saying the binary output of the opamp's simple circuit will change.  If you think it changes after 40 hours, it would only make sense to say it will still be changing at 400 hours and 4000 hours (which would not be good for any SS electronics).  I know this whole subject has a kind of notorious debate around it, but from an Electrical Engineering student (Jr.) this is my opinion on the subject.


----------



## Avro_Arrow

ncsuzoso said:


> "Break in" is a mechanical term that refers to things like speakers or anything using a suspension system like phono cartridges for example.  The term you _would_ use for opamps is burn in, but many people (including myself) believe it is more your brain burning in when it comes to SS electronics.  Now when you talk about about tubes or even capacitors, there is some truth to it (it can actually be proven when you measure the output of the circuit), now an Opamp "breaking/burning in" that is the same as saying the binary output of the opamp's simple circuit will change.  If you think it changes after 40 hours, it would only make sense to say it will still be changing at 400 hours and 4000 hours (which would not be good for any SS electronics).  I know this whole subject has a kind of notorious debate around it, but from an Electrical Engineering student (Jr.) this is my opinion on the subject.


 

 Can you imagine the captain of an airliner, telling his passenger after the plane lands in a corn field, that the planes navigation system will work better once it's had a chance to burn in?
 The idea that a transistor, op amp or some other solid state electronics degrades in an audible way that fast is just a joke.


----------



## Robin W.

I don't agree or disagree with burn in, I believe I've encountered it, but subjective listening isn't proof given the time frames involved, but I've never been able to measure it.  I do however believe in warm up, not all devices seem to behave the same (IE some don't seem to audibly change), but some do have a subjective difference after 15-30 minutes of idle or low volume playback.
  
 For those of you interested in Muses but don't want to invest $50-75 a piece in op-amps try the Muses8920, it's much cheaper but still sounds incredible.  In my application I much prefer the Muses8920 to the Muses02 (I can't use the Muses01 because the rail voltage is too low in this battery powered amp).


----------



## NCSUZoSo

Warm up is a completely different concept from burn in and I do believe in warm up, a tube amp is a great example of that.
  
  
 Quote:


avro_arrow said:


> Can you imagine the captain of an airliner, telling his passenger after the plane lands in a corn field, that the planes navigation system will work better once it's had a chance to burn in?
> The idea that a transistor, op amp or some other solid state electronics degrades in an audible way that fast is just a joke.


 
  
  
 I was just making a point by saying it would still be changing, I wasn't saying I believe that is the case.


----------



## razzz42

The way I understand it from CPU burn-in discussions in the past elsewhere, the path on the track or trace can widen by a few atom widths during initial usages depending on what areas of the chip are being used and leaves less resistance for a signal to travel on/in. That was a really an oversimplification, more to do with heat and expansion esp. concerning copper, but the PhDs would argue if it was even possible in theory and the fact they would even discuss it gave it some credence.
  
 Headphones and speakers or cone driven sources are a simple matter of loosening up the material(s)  (flexing) so it can travel further and push more air around. Some cone materials are made of composites and can be stiff and may take months of hard usage to break in. Or the lesser materials will fatigue quickly over time and not be as responsive. That an oversimplification too but I don't think anyone will argue about it.
  
 Heaven forbid a flame war breaks out on the burn-in subject but this MUSES01 sounded flat and lacked bass on first listen. After 8 hours of continuous operation sounded much better to me. My imagination?  Only needed a few hours of 'warm up' and no more? I don't know but I have gone from wanting to pull it out right away and go back to what I had, to now leaving it in for a while longer.


----------



## wes1099

Hey guys, I just put an opamp backwards into this 18v cmoy, and i was wondering what to do to fix it. I suspect i fried the opamp, but i wanted to know if i could have fried anything else. Can i just replace the opamp and have everything work again? You can find a diagram of the circuit here.


----------



## mcandmar

It should be fine, opamp is probably toast though but worth trying it anyway.


----------



## wes1099

Will a pdip8 opamp work in a dip8 rig?


----------



## ClieOS

wes1099 said:


> Will a pdip8 opamp work in a dip8 rig?


 
  
 PDIP8 is a type of DIP8.


----------



## razzz42

wes1099 said:


> Will a pdip8 opamp work in a dip8 rig?


 
 http://www.siliconfareast.com/pdip.htm


----------



## SWIN

Are you people sure about buying MUSES from .cn?
  
 They seem to me to be masters of copying and faking just about everything.
  
 Or, is it just me....


----------



## Robin W.

Mouser has a couple types from the muses series in stock, including the Muses01.  Definitely not the best price in low quantities however you know they are legit.  Probably more cost effective to get the real one the first time than to get a fake and replace it later.


----------



## gibosi

In the end, everyone needs to do their due diligence and go with a vendor they feel comfortable with. That said, I did my due diligence and felt very comfortable purchasing both the MUSES 01 and MUSES 02 from the same eBay HK vendor. And in my humble opinion, if what I received are fakes, then they are incredibly good fakes. The MUSES 02 I received is now installed in my Little Dot 1+ and it is giving me the best sound ever. Cheers.


----------



## SpudHarris

When I started out I got my fingers burned once or twice..... I now firmly believe that if an OpAmp is being sold for considerably less (taking into account quantity break points/discounts) the the chances are it's not going to be the real deal. Like I said before, there are some great sounding OpAmps out there that are begging to be rebranded and placebo will fill in the gaps.

The only true way to know is to buy from a registered re-seller. Another giveaway is the unique packaging....


----------



## gibosi

spudharris said:


> When I started out I got my fingers burned once or twice..... I now firmly believe that if an OpAmp is being sold for considerably less (taking into account quantity break points/discounts) the the chances are it's not going to be the real deal. Like I said before, there are some great sounding OpAmps out there that are begging to be rebranded and placebo will fill in the gaps.
> 
> The only true way to know is to buy from a registered re-seller. Another giveaway is the unique packaging....


 
  
 It appears that you are suggesting that I have likely been duped and I probably don't even know it...  To be frank, I find this to be a tad bit insulting... But to each his own. 
  
 However, as I mentioned *before*, if I buy 500 or more of these chips from Mouser, I would get a significant price break and could easily sell them for around $40 each, and still make a profit. And while I do not know for sure, I strongly doubt that when purchased in such large quantities. each individual chip is going to packaged in such a unique and expensive manner. After all, if I was purchasing them to be incorporated into an audio product, such packaging would be terribly wasteful. So I can see no reason why a legitimate eBay vendor based in the HK couldn't buy a very large quantity of these chips, with no fancy packaging, and resell them for a bit over $40.
  
 (And I should note that if eBay discovers that a vendor is selling fakes, they kick him off their system. No reputable vendor would want to take such a risk.)
  
 In the end, while I cannot be 100% certain, I seriously doubt that I have been duped, and I am very comfortable with my decision.


----------



## zilch0md

I think Spud was just expressing his own concerns from having been burned in the past, with no intent to hurt your feelings.  
  
 I haven't ordered the Muses 02 yet, because I can't find it in stock at the official re-sellers (including Mouser), but I'm not willing to take a chance, so I'm waiting - and I don't want you to feel bad about your purchase, by doing so.


----------



## SpudHarris

The eBay seller who ripped me off 4 years ago is still selling today.

Why would my OpAmp come in such packaging because I bought 1 off from Audiotrak? (They have thousands and thousands of them) Are you saying it would be different from Mouser? Farnelll? RS Components? etc.... I guess the only way to find out is to order from them? I only have the 02 and am curious of the differences between this and the 01.

This is nothing personal and I don't want to make you feel bad but these scum bags are ripping people off.


----------



## Robin W.

For what it's worth this is a picture of a legit Muses02.
 The most significant physical difference I've noticed is the leads are soft and flexible.  IE part of the Muses design is the copper frame, so the leads don't feel like most normal op-amps which are a bit stiffer.
 It's less likely that someone trying to fake A Muses would go through the trouble and expense of re-creating the copper frame and leads.  I've never had a fake so I couldn't say for sure, however it's the first thing that I would check.  Also the silkscreen is very clear and sharp though it is still a standard dot printing method.


----------



## gibosi

spudharris said:


> When I started out I got my fingers burned once or twice..... I now firmly believe that if an OpAmp is being sold for considerably less (taking into account quantity break points/discounts) the the chances are it's not going to be the real deal. Like I said before,* there are some great sounding OpAmps out there that are begging to be rebranded and placebo will fill in the gaps*.


 
  
 I was primarily reacting to the bolded words. The inference is that a buyer, such as myself, might not even know it is a fake. However, while I found this to be a somewhat insulting, I felt that no insult was meant, and in turn, I took no offence. 
  


spudharris said:


> The eBay seller who ripped me off 4 years ago is still selling today.
> 
> Why would my OpAmp come in such packaging because I bought 1 off from Audiotrak? (They have thousands and thousands of them) Are you saying it would be different from Mouser? Farnelll? RS Components? etc.... I guess the only way to find out is to order from them? I only have the 02 and am curious of the differences between this and the 01.
> 
> This is nothing personal and I don't want to make you feel bad but these scum bags are ripping people off.


 
  
 Of course, I don't know the specifics of your case, but I have seen eBay take strong action on several occasions. Several vacuum tube auctions in which I was bidding were stopped when someone reported something amiss. And in one instance, not only was the listing pulled, but the vendor's store simply disappeared. So while it seems that your vendor managed to escape unscathed, I have seen at least one banned.
  
 Bulk packaging associated with large quantity orders is often quite different than what I would call "consumer packaging". Again, if I were to order a large number of opamps for a product I was manufacturing, I would ask for bulk packaging. Otherwise, I would have to extract a 1000 chips from their cases and then all those nice plastic cases would have to be pitched - a waste and a hassle. So it is only reasonable to think that these chips can be ordered with cases, or without, per the buyer's request.
  
 However, I fully endorse the intent of your words: "Buyer Beware"
  
 Cheers


----------



## gibosi

On the chance that these may be of interest, some pics of my MUSES 01. I don't have much experience with handling opamps, so it is difficult for me to compare the stiffness of the leads.


----------



## psygeist

I got two more muses01.


@spud 
can you post the pics of your muses02's sides adjacent to the pin sides ?


----------



## psygeist

robin w. said:


> For what it's worth this is a picture of a legit Muses02.
> The most significant physical difference I've noticed is the leads are soft and flexible.  IE part of the Muses design is the copper frame, so the leads don't feel like most normal op-amps which are a bit stiffer.


 
 Can confirm this. Compared to other opamps the leads are much more nimble.
  
 Tried MUSES 01 in main circuit and at the output stage too. Sounded kind of dryish thin.'
  
 Changed back output stage to OPA627 AD8620, lean but warm signature. I guess this setting will never get beaten by any other combination.
  

 Forgot to look which opamp was in output stage. It's actually AD8620.


----------



## SpudHarris

Here are some pics of the Muses02 with other OpAmps for reference. The legs in comparison to other OpAmps seem very pliable, almost flimsy I'd say and appear a lot lighter in colour.


----------



## wes1099

What would be the best chips for my 18v cmoy with a dip-8 socket?


----------



## SWIN

In light of the problem of identifying the MUSES series OP Amps, one would wish, that NJR would set up an official e-bay store.
  
 There are so much money to be earned by faking these IC´s, any cheap DIP8 would be the base.
  
 I bought mine from .jp, hoping that the closeness to the source would get me the real things.
  
 Only listened so far to the MUSES01, and the MUSES8920, and in my setup the 8920 sounds a bit rounded of at the extremes (bass & treble), and a bit cautious.
  
 The 01 on the other hand is very neutral, and definitely sounds like very high end.
 It has a firm deep bass, and extended highs - all with a very listenable, and enjoyable tone.
  
 On the other hand, who knows what IC´s I am listening to 
  
 Are the legs of the IC´s of a different material, tried to scrape the surface of my 01´s legs, but unsure about the result.


----------



## highfell

psygeist said:


> Can confirm this. Compared to other opamps the leads are much more nimble.
> 
> Tried MUSES 01 in main circuit and at the output stage too. Sounded kind of dryish thin.'
> 
> Changed back output stage to OPA627, lean but warm signature. I guess this setting will never get beaten by any other combination.




So you prefer the OPA627s? In what amp by the way?


----------



## psygeist

highfell said:


> So you prefer the OPA627s? In what amp by the way?




I prefer MUSES 01 in main circuit and OPA627 AD8620 in output stage.

I tried MUSES 01 in output stage but it sound too dry to me. May be I need extended listening.

Amp is LEAR FSM02 V2.


Forgot to look which opamp was in output stage. It's actually AD8620.


----------



## Audiofanboy

Alright, just got 5 MUSES02 and a pair of MUSES01 in the mail--those ebay fakes you know lol.
  
 First off, not that I really care much or I like to argue, but I have _very_ little reason to assume these are fakes. Lettering, holes and pins are exactly the way the "true" MUSES have been described; and beyond that, the sound kind of confirms their genuineness as far as I'm concerned. And yes, the pins are actually pretty flimsy compared to my usual chips, so much so you could bend them beyond repair way too easily... Be warned...
  
 Anyway, onto impressions now. I tested (I'd love to be allowed to say "put to burn-in" but I'm afraid I'll get a public stoning if I do lol) three MUSES02 in my iBasso D10 (one I/V, two buffers) first. Pretty immediate difference compared to my three OPA627AU combination from before. Replacing the I/V opamp made a huge difference (both in terms of sound quality and "flavor") whereas swapping the buffer opamps made more of a "sound color" difference listening upon first listen, even though the sound quality clearly ramped up at the same time.
  
 These are obviously pretty powerful chips here, heavy hitting and loud. Not exactly neutral right out of the box, bass seems a little overwhelming (D10 is connected to my old iRiver H120, while this is a great mobile setup, with pretty good sound quality, the bass does have that "jitter party" effect where it is more thumpy than tactile, and the MUSES02 kind of emphasizes that), but soundstage and sound quality are on a total different level from the previous chips, cavernous (not large) and wet (not grainy). If the bass gets a little tamer after a few hours--wait that's impossible, I forgot, semiconductors don't evolve with time!-- this could be a pretty good opamp for a mobile setup, where "loudness" and bass with a good level of detail can be more important than the hyper-critical detail retrieval and resolution I would look for on my home rig.
  
 MUSES01 now. Tested a pair of these in my DAC output, in my main home setup, replacing two pairs of AD797BR opamps--my reference chips up to now--feeding my tube headamp. Interestingly, the first second of the first song I played, I noticed the difference in sound quality with the AD797, _but_ I also noticed _no_ change in sound "color" or "flavor". What does this mean? Well, simply that the MUSES01 is a better opamp than the AD797 in that position, but that's it's just as neutral, which is both good and what I'm looking for (last thing I need is a "colorful" opamp in my DAC like the OPA627...).
  
 The sound is nicely balanced throughout the whole frequency spectrum--if anything, I find myself expecting a tad more bass out of the box, but I'm pretty sure that will solve itself in the first few hours, you know,_ brain burn in_-- with no frequencies dominating the sound. I am hearing more details than with the AD797, better defined, both spatially and in resolution; the soundstage isn't particularly large  as I've read (it is a little larger and higher than the AD797, but not deeper), but very 3D-holographic sounding with pleasantly realistic instrument placement and separation. No particular wetness here, apart from what the tubes add in my setup; just a neutral 3D ultra-detailed sound: a better-made AD797 really... I'm surprised by how similar these chips sound--or don't sound actually, since they're so neutral...
  
 Anyway, I will "monitor" the evolution of the opamps in both setups, and report back when _my brain has burnt-in_ lol.


----------



## zilch0md

That was a nice comparison of the 01 and 02!   Thanks very much!
  
 Mike


----------



## razzz42

> "...MUSES01 now. Tested a pair of these in my DAC output, in my main home setup, replacing two pairs of AD797BR opamps--my reference chips up to now--feeding my tube headamp. Interestingly, the first second of the first song I played, I noticed the difference in sound quality with the AD797, _but_ I also noticed _no_ change in sound "color" or "flavor". What does this mean? Well, simply that the MUSES01 is a better opamp than the AD797 in that position, but that's it's just as neutral, which is both good and what I'm looking for (last thing I need is a "colorful" opamp in my DAC like the OPA627...).
> 
> The sound is nicely balanced throughout the whole frequency spectrum--if anything, I find myself expecting a tad more bass out of the box, but I'm pretty sure that will solve itself in the first few hours, you know,_ brain burn in_-- with no frequencies dominating the sound. I am hearing more details than with the AD797, better defined, both spatially and in resolution; the soundstage isn't particularly large  as I've read (it is a little larger and higher than the AD797, but not deeper), but very 3D-holographic sounding with pleasantly realistic instrument placement and separation. No particular wetness here, apart from what the tubes add in my setup; just a neutral 3D ultra-detailed sound: a better-made AD797 really... I'm surprised by how similar these chips sound--or don't sound actually, since they're so neutral...
> 
> Anyway, I will "monitor" the evolution of the opamps in both setups, and report back when _my brain has burnt-in_ lol.


 
  I'll confirm Audiofanboy's findings with the MUSES01. Same Chinese knockoff, er....I mean purchase, placed in the output on an Audiotrak Prodigy HD2 pci card. Only difference is I have LME49990MA in the I/V sockets feeding it.  I was using an adapter holding (2) LT1028-ACN8 in the output. I still prefer the LT1028 setup but if I had never tried different opamps, the MUSES01 would sound very impressive but an overall step down from LME499990.  In combination the MUSE01 adds a bit of clarity to spread or enhance the staging (airiness). Only slightly bass lite to what I am accustom to lately. Does bring everything forward to lose a bit of dimension but you would never notice unless you know what to listen for (depth). Handles the mids and high well, maybe slightly bright. A decent purchase if under $30. Certainly beats OPA627 but anything would.  Ever since the LME499990 my AD797s have been in the back of the drawer for a couple years now.
  
 Can't speak to MUSE02, don't have any.
  
 [Surreal burn-in needs to happen continuously for at least 8 hours or mental gain is lost.]


----------



## psygeist

So, been listening to the setup where MUSES 01 is in main circuit and at output stage. Feels a lot like RE272 signature. Slightly brighter to my ears but incredibly detailed. Mids are more upfront.


----------



## NCSUZoSo

Finally got my last Opamp in:


----------



## psygeist

Never have I tried eqing but with ZX1 as source and Muses 01 in main and output stage I find setting clear bass in ZX1 to +2 is the sweet spot.


----------



## NCSUZoSo

Is that Sony ZX1 really almost $1000 for a high fidelity MP3 player?
  
 I'd look at the Cowon devices for that price, like the Cowon iAUDIO 9+
  
 I'm not trying to insult the ZX1 or it's owners, I'm just curious why you would pay that much money for a MP3 player with options like Cowons out there.


----------



## ppataki

Hi Everyone,
 I got a Sound Blaster ZXR card and I am planning to replace the op-amps on it
 I was thinking about the MUSES02 as the I/V op-amp (dual) but I am not sure about the buffer op-amp (single)
 Can you please recommend some nice analog sounding DIP8 buffer op-amp to match with MUSES02? (or shall I just leave the original LME49710NA there with the MUSES02)
 Thank you in advance


----------



## NCSUZoSo

Well before recommending anything there are two questions I need to know first.
  
 1. What is below your sound card in the next slot?  In other words how much space do you have beneath it?  If you have a video card directly below it then you can't run some op-amps that use adapters.  Also in general the space is limited on the board with what will fit if you use adapters.  You can see how tight the fit is on my AD8597 to a DIP8 adapter.
  
 2. Do you want to be able to put the EMI shield back on after your upgrade?
  
 After we know the space you have to work with vertically that will narrow (or open up) the options.
  
 I can tell you right now that no full size Single DIP8 to Dual DIP8 adapter is going to fit on that board and fit with either the shield on or if you have a card in the slot directly below the card (I've tried to do it with the stock LME49710s with a GPU in the slot directly below)
  
 I am talking about an adapter like this:
  

  
  
 Also there is some debate on which Opamp is actually connected to, I intend to do a multimeter test to verify it soon.  Creative claimed that all the replaceable opamps go with the left and right channels, but people on other boards which are more PC based do not believe the ZXR has enough gain to push a 4 stage output buffer or a 2 stage push/pull.
  
 "Kevmatic" from OCN Forums opinion on what Creative sent me:
  


> That means either a 4-stage output buffer or a 2 stage push-pull. I HIGHLY doubt either would be true- its not necessary- the gain can't be high enough for 4 stages and a push-pull for opamps is redundant. It could also have them paralleled to drop the output impedance, but that's what the headphone amplifier is for....


 
  
 He and I are referring to this picture Creative Support sent me:


----------



## ppataki

Hello,
 Basically I would like to keep the EMI shield so ony DIP8 op-amps could work, no adapters
  
 (I also read on other forums that all 4 op-amps drive only the 2 front channels)
  
 Thank you in advance


----------



## NCSUZoSo

What kind of budget are you looking at?  Also do you plan on purchasing from a source like Ebay or will you only stick with verified retailers like Digikey or Mouser?
  
 Are you located in the US or where?  Also you can use adapters like the ones you see in my picture above, I have the shield installed on that card with zero clearance problems (all those are lower than the caps in height).


----------



## DingoSmuggler

ncsuzoso said:


> Also there is some debate on which Opamp is actually connected to, I intend to do a multimeter test to verify it soon.  Creative claimed that all the replaceable opamps go with the left and right channels, but people on other boards which are more PC based do not believe the ZXR has enough gain to push a 4 stage output buffer or a 2 stage push/pull.


 
 That burr brown DAC has balanced current outputs, so the analogue stage would almost certainly have to be...
  
 Balanced I/V(dual opamp) into single opamp buffer (or the h/p amp) which is also acting as a Balanced to SE converter.
  
 So in other words, remarkably similar to the ST/X, or the manufacturer's datasheet for that matter.
  


ppataki said:


> Can you please recommend some nice analog sounding DIP8 buffer op-amp to match with MUSES02? (or shall I just leave the original LME49710NA there with the MUSES02)


 
 Can't speak for any potential of _synergies_ with the MUSES02, not having heard the combo, but the LME49710 is an ideal buffer for line level audio. I would certainly try it, maybe it is not the absolute best choice for you, but it will certainly not be a bad choice.


----------



## ppataki

The budget is not a main concern, I am living in Europe and actually I have already purchased a MUSES02, I am just concerned about the buffer op-amp
 Cheers


----------



## NCSUZoSo

I too do not have a MUSES02 to compare against, but I have heard good things about the LME49990:
  
 http://www.ebay.com/itm/LME49990-single-SOIC-to-DIP8-adapter-low-noise-op-amp-/151119171631?pt=LH_DefaultDomain_0&hash=item232f67902f
  
 That will fit without issue.


----------



## psygeist

ncsuzoso said:


> Is that Sony ZX1 really almost $1000 for a high fidelity MP3 player?
> 
> I'd look at the Cowon devices for that price, like the Cowon iAUDIO 9+
> 
> I'm not trying to insult the ZX1 or it's owners, I'm just curious why you would pay that much money for a MP3 player with options like Cowons out there.


 
 It's pretty good. I don't have anything much to compare but the best setup I have heard. May be the cost is on higher side but not when you have atrociously priced bricks.


----------



## Robin W.

ppataki said:


> The budget is not a main concern, I am living in Europe and actually I have already purchased a MUSES02, I am just concerned about the buffer op-amp
> Cheers


 
 If you like the sound of the Muses02 Plus LME49710NA you could try the LME49710HA, which is the metal can version of the same op-amp.  It has a very similar sound with a bit more detail and openness.


----------



## NCSUZoSo

He won't be able to fit a metal can version with its adapter and the card's EMI shield, I was running OPA627SM, so I know.


----------



## zilch0md

ncsuzoso said:


> Is that Sony ZX1 really almost $1000 for a high fidelity MP3 player?
> 
> I'd look at the Cowon devices for that price, like the Cowon iAUDIO 9+
> 
> I'm not trying to insult the ZX1 or it's owners, I'm just curious why you would pay that much money for a MP3 player with options like Cowons out there.


 
  
 I hear you!  
  
 And with only 15mw per channel into 16 Ohms, at that!   The ZX1 is for efficient IEMs, only!  
  
 And then Sony offers the PHA-2, which has a killer, DSD-capable DAC, that can be fed digitally from the ZH-1, which is great, but the PHA-2's amp section only outputs 90mW per channel into 32 Ohms - which might be fine for efficient headphones and IEMs, but there are a _lot_ of portable headphone amps that can deliver 500mW or more per channel (RSA, CEntrance, ALO, iBasso, Triad, etc.) for use with headphones that are _not _efficient.  Audeze support recommends 1000mW into 50-Ohm, for example, but the crazy expensive PHA-2 only outputs 58mw into 50-Ohms!
  
 Ironically, the TPA6120A2 amp chip inside the PHA-2 is being powered by only a 3.7V battery, but the datasheet for the TPA6120A2 shows that it can deliver 1500mW into 32 Ohms if given a supply voltage of 12V (instead of 3.7).  And if you supply that same chip with 15V, it will deliver 2000mW into 32 Ohms!!    
  
 But Sony seems to think that keeping the PHA-2 small and light, with an output of only 90mW into 32 Ohms, is more important than unleashing the potential of that TPA6120A2 with a larger, higher-voltage battery pack!  And get this:  The PHA-2 doesn't even allow you to supply a higher voltage via an external power jack (as with the Meier Audio, iBasso, and Triad Audio amps, not to mention others).  Nope!  The only power input allowed with the PHA-2 is a 5V port for recharging the 3.7V battery from a USB source!   How convenient!   Give me a break!
  
 The only saving grace for the PHA-2 is that it comes with an analog Line Out jack - so that you can bypass it's paltry amp section and connect it to a real headphone amp!
  
 I LOVE Sony for their UIs and their build quality, but they are clueless when it comes to recognizing how important output power is for sound quality!
  
 End of Mike's Rant.


----------



## Robin W.

ncsuzoso said:


> He won't be able to fit a metal can version with its adapter and the card's EMI shield, I was running OPA627SM, so I know.


 
 You don't need an adapter to plug in a TO-99.  The pin arrangement is identical you simply need to form and trim the leads.  When I do it the can itself is slightly higher off the dip socket than a pdip so if done well you would need 2-4mm above a standard PDIP.  (depending on your skill level at forming the leads you might even get it basically the same height as a standard dip since the can is actually shorter than a dip, you just need room to form the leads and not short them to the can)
  
 I'm not endorsing this seller, just using the image as an example of formed leads that fit into the dip socket in a low profile way.  There is no need to solder anything, they plug in just like a normal dip but with a little extra care in pin alignment.  So the dip socket in the photo would be the one on the PCB, you are not adding an adapter on top of the PCB dip socket.
http://www.ebay.com/itm/LME49720HA-Adaptor-/170895883832
  
 I have a hand full of LME49720HA's that are not soldered to dip carriers, I simply plug in the TO-99 package into a dip socket on the PCB when I want to test them.
  
 ****If you don't have 2mm+ above the top of the dip or have good mechanical skills then please ignore this as it likely wouldn't fit.


----------



## NCSUZoSo

It is pretty obvious the pin arrangement is identical or you couldn't use an adapter with a round solder arrangement.  However you need to look at the data sheet to see where pin 1 is or you'll end up bending the pins in the wrong arrangement.


----------



## SpudHarris

Muses01 came today from the official e-bay seller, Gyrocom C&C Korea. Same great packaging as the Muses02. Too early to compare the two but I can say that it is very, very nice indeed. 





Will be buying from this seller from now on as I always get stung for customs and admin when ordering direct from Audiotrak.


----------



## psygeist

Its the same, audiotrack linked ebay store.

Do you prefer MUSES 01 over MUSES 02 ?


----------



## zilch0md

spudharris said:


> Muses01 came today from the official e-bay seller, Gyrocom C&C Korea. Same great packaging as the Muses02. Too early to compare the two but I can say that it is very, very nice indeed.
> 
> 
> 
> ...




Hey Nigel!

Is this the source you are referencing?

http://www.ebay.com/itm/AUDIOTRAK-MUSES-02-OPAMP-High-Quality-sound-bipolar-input-dual-oerational-amp-/111080427256

And should I order only two of these Muses 02 for the PB2 in the input gain stage?

Thanks!!

Mike


----------



## SpudHarris

zilch0md said:


> Hey Nigel!
> 
> Is this the source you are referencing?
> 
> ...


 
  
 Hi Mike,
  
 well as they are so expensive, I have ordered only one of each for evaluation before committing to more. I listened to the 01 exclusively last night and it is up there with the best of the best for sure but I have had the 02 for a while and I am definitely in love with it. 
  
 I haven't slipped back into my old rolling ways, I spend far longer evaluating now, I guess I'm maturing at last haha


----------



## zilch0md

Haha! Yeah, this isn't rolling.  Installing the Muses 02 will be the last time I open my PB2 case! 

Thanks!


----------



## SpudHarris

So you are leaning towards the 02 then? I think that's the right choice Mike. 01 is good, great even but I'm completely sold on the 02's.


----------



## zilch0md

It's hard to believe there might be something better than the LME49990 in the PB2, but I'm going to try the 02 (x2).


----------



## NCSUZoSo

I have a genuine MUSES01 I am considering selling so as to match my setup with another ADA4627-1BRZ (SOIC8 (x2) to DIP8):
  
  

  
  
 Figured I'd mention it with so many people interested in MUSE amps.


----------



## SJWorne

Hey guys,
 It's probably been mentioned somewhere before, but I can't see it, or find it, but could someone link me to the differences between the MUSES 01 and 02?  
 Or even better, could somebody detail it here? 
 These are 2 channel amps aren't they?


----------



## ClieOS

Can't remember if I have mentioned these in here or not but I reckon I will say it again: If you are only ordering one MUSES, you can order it from Mouser. It is around $75~80 but usually come with free shipping when you pay with local currency. If you are ordering more than one, you can get it from JRC Japanese distributor, akizukidenshi.com, by using the buying service from Tenso. It is only $35 each, with $15 buying service charge, $5 shipping (inside Japan), $5 Tenso usual fee, and up to $20 EMS shipping. So the total is $80, which means the single price from ordering from either Mouser or Japan is about the same. But once you order two, it is will be $150 from Mouser vs. $115 from Japan. So the more you order, the more you will save by buying them from Japan. Also you can be sure both are genuine as they are both listed by JRC as MUSES distributor.
  
  
 My personal view on MUSES 01 vs. 02 is that 01 is more musical, full and rich, really excel in vocal. 02 on the other hand is more neutral (though not total neutral), with better clarity and soundstage, particularly suited for Classical.


----------



## ppataki

zilch0md said:


> It's hard to believe there might be something better than the LME49990 in the PB2, but I'm going to try the 02 (x2).


 
  
 Here is what I finally did:
 I ordered MUSES02 and decided to go for a pair of LT1028ACN8s as buffer (it was suggested on Japanese forums)
 Well, I have to say I was not satisfied with the sound, the highs were metallic and too crispy while the mids were too harsh - on the other hand the stage was really wide and deep and the bass became more powerful (I also tried the LME47910s as buffer but it did not get any better)
  
 I decided then to go for the LME49990s as both I/V and buffer (SOIC to DIP8 adapter version)
 The difference was astonishing, now everything is in its place 
 It sounds warmer, more tonally balanced and somewhat 'cleaner', I am totally happy with it!
  
 I think after all it is all about personal taste, but it is definitely worth experimenting


----------



## zilch0md

With the LCD-2, I prefer the PB2 equipped with...

this... LME49990 in I/V + dummy buffers

rather than... LME49990 throughout.

I hear the same tonal balance, but with greater clarity, at the expense of power.

The LCD-2 are efficient enough that by using balanced cables, instead of the PB2's single-ended output, and using 16V external power, instead of the 12.6V internal battery, I still get plenty of dynamics and bass control.

http://www.head-fi.org/t/528149/ibasso-pb-2-pelican-fully-balanced-portable-db-2-dac-hiflight-recommended-op-amps-page-16/615#post_8360318

Mike


----------



## razzz42

ppataki said:


> Here is what I finally did:
> I ordered MUSES02 and decided to go for a pair of LT1028ACN8s as buffer (it was suggested on Japanese forums)
> Well, I have to say I was not satisfied with the sound, the highs were metallic and too crispy while the mids were too harsh - on the other hand the stage was really wide and deep and the bass became more powerful (I also tried the LME47910s as buffer but it did not get any better)
> 
> ...


 

  
   
  
 Quote:


zilch0md said:


> With the LCD-2, I prefer the PB2 equipped with...
> 
> this... LME49990 in I/V + dummy buffers
> 
> ...


 
  
 I was running LME49990 in the I/V sockets and LT1028ACN8s in the buffer before I tried MUSES01 in the buffer. The O1 sounded okay but lacks compared to the LT1028ACN8s. I went back to the LT1028ACN8s in the buffer with absolutely no regrets.
  
 LME49990 in I/V sockets seem to be a must at this point in time: The buffer socket you can leave empty or experiment with any quality opamp in seeking out what you prefer or need for your phones or speakers. The LT1028ACN8s works well in the buffer socket for my tastes whether it's thru headphones or speakers.
  
 Of course you need two LT1028ACN8 on an adapter board plus the room around the buffer socket to plug in the adapter board. Could be a drawback for some but I am running an AUDIOTRAK Prodigy HD2 ADVANCE DE (need a PCI slot) so no problems (see card pics at link).


----------



## zilch0md

Somebody stop me, before I start rolling op-amps again!


----------



## SpudHarris

I have been AB'ing between the Muses 01 and 02 and whilst dismissive of the 01 over the 02 initially, I am beginning to like the 01 (a lot). I had been using the 02 pretty much exclusively with HD800's so that's what I used to initially evaluate the 01. I listened to the 01 tonight with my LCD3 and have to say there is a synergy.

The 02 with the HD800 is clean, detailed (as expected with HD800's) but never fatiguing. The 01 with the LCD3 is organic and musical. I am listening to Vataff Project - Maemoa, and I can't remember a time it sounded more analogue, involving....

I will order another of each :rolleyes: oh man....


----------



## NCSUZoSo

Most people I hear review the two always lean towards the 01 when they A/B them.  I am not sure if I am going to sit on my MUSES01 or sell it, it's genuine (straight from Japan).  However if I'm not going to change it again, it would be a waste to have an opamp like this just sitting.


----------



## zilch0md

spudharris said:


> I have been AB'ing between the Muses 01 and 02 and whilst dismissive of the 01 over the 02 initially, I am beginning to like the 01 (a lot). I had been using the 02 pretty much exclusively with HD800's so that's what I used to initially evaluate the 01. I listened to the 01 tonight with my LCD3 and have to say there is a synergy.
> 
> The 02 with the HD800 is clean, detailed (as expected with HD800's) but never fatiguing. The 01 with the LCD3 is organic and musical. I am listening to Vataff Project - Maemoa, and I can't remember a time it sounded more analogue, involving....
> 
> I will order another of each :rolleyes: oh man....




Makes sense to me, considering the difference between HD800 and LCD-2 (that I have).


----------



## razzz42

Rolling opamps is cheaper than buying new headphones. Too bad the studios can't say which opamps they used for the final mix output for their master.
  
 The various sound formats on newer DVD and Bluray make sounds even more enjoyable..


----------



## Robin W.

razzz42 said:


> Rolling opamps is cheaper than buying new headphones. Too bad the studios can't say which opamps they used for the final mix output for their master.
> 
> The various sound formats on newer DVD and Bluray make sounds even more enjoyable..


 
 You really need to take into consideration the amp itself.  You could put the same op-amp into two different amps and get entirely different sounds depending on the circuit design.  Think of it like synergy between headphones and an amp, or an amp and a dac etc. In one combination they might be the best thing since sliced bread, but another combo of equality good equipment might be hardly listenable.
  
 Many pieces of studio gear that I've seen that use op-amps just use high quality jelly-bean (generic) versions like the NJM4556 which is quite a good op-amp especially considering the price, same company but none of the hype or buzz words of a MusesXX.
  
 (***Just to be fair, I do really enjoy the Muses and am using the Muses8920 in one of my designs, but my amp will only have 5 op-amps, not practical for a Muses01/02 at my target price point, however it is worthwhile to step above the NJM4556/OPA2134 given the performance difference with the circuit configuration I'm using)


----------



## NCSUZoSo

You also have to keep in mind you can change more than opamps, like changing out Primary/Secondaries/Headphone Amp capacitors (if that is possible on your specific DAC).


----------



## highfell

spudharris said:


> I have been AB'ing between the Muses 01 and 02 and whilst dismissive of the 01 over the 02 initially, I am beginning to like the 01 (a lot). I had been using the 02 pretty much exclusively with HD800's so that's what I used to initially evaluate the 01. I listened to the 01 tonight with my LCD3 and have to say there is a synergy.
> 
> The 02 with the HD800 is clean, detailed (as expected with HD800's) but never fatiguing. The 01 with the LCD3 is organic and musical. I am listening to Vataff Project - Maemoa, and I can't remember a time it sounded more analogue, involving....
> 
> I will order another of each :rolleyes: oh man....




Very interesting to read.

I am hoping to get some in few weeks time. I have been given the following information about the differences Muses01 & 02 is shown below, which I thought it would be interesting to share. 

The real difference is that MUSES01 is JFET whereas the 02 is Bi-polar. The 01, being a JFET, has a much higher slew rate and they sound very different indeed. All JFET op-amps tend to sound brighter and tighter in the top end with Bi-polar’s tending to give a warmer sound. It’s a crude way of looking at them but as a ‘rule-of-thumb’ it works. The circuit around them obviously has an effect as well. 

The majority of Europeans have gone for the warmth of the 02 against the tightness of the 01, but then we have European ears. If you go to Japan or China, they tend to prefer the 01, but then listen to a Japanese person singing and you’d notice they tend to have a higher pitched voice than an European. It is no surprise that they would go for the 01. Also, people who fall in love with reproduced music in Europe, particularly in the UK and the USA still have a fondness for vinyl and valves, it’s the warmth we seem to hear first, then the detail.


----------



## SpudHarris

highfell said:


> Very interesting to read.
> 
> I am hoping to get some in few weeks time. I have been given the following information about the differences Muses01 & 02 is shown below, which I thought it would be interesting to share.
> 
> ...




To me the 02 has synergy with the HD800 which kind of figures considering it is the more mellow of the two OpAmps. Same goes for the 01 with the darker tone of the LCD3. I've tried all my phones with each OpAmp (in the same amp) and these are the two combos that float my boat. I can only imagine what an optimised circuit for each must sound like....


----------



## NCSUZoSo

Such as the Xonar Essence One Muse Edition?


----------



## SJWorne

highfell said:


> Very interesting to read.
> 
> I am hoping to get some in few weeks time. I have been given the following information about the differences Muses01 & 02 is shown below, which I thought it would be interesting to share.
> 
> ...


 
 Funny... I would prefer the brighter one of the two I think, so I will have to grab one of each to try with my LD1+


----------



## razzz42

robin w. said:


> You really need to take into consideration the amp itself.  You could put the same op-amp into two different amps and get entirely different sounds depending on the circuit design.  Think of it like synergy between headphones and an amp, or an amp and a dac etc. In one combination they might be the best thing since sliced bread, but another combo of equality good equipment might be hardly listenable.
> 
> Many pieces of studio gear that I've seen that use op-amps just use high quality jelly-bean (generic) versions like the NJM4556 which is quite a good op-amp especially considering the price, same company but none of the hype or buzz words of a MusesXX.
> 
> (***Just to be fair, I do really enjoy the Muses and am using the Muses8920 in one of my designs, but my amp will only have 5 op-amps, not practical for a Muses01/02 at my target price point, however it is worthwhile to step above the NJM4556/OPA2134 given the performance difference with the circuit configuration I'm using)


 
 Sure these mini platforms for audio production vary. A DAC surrounded by a bunch of cheap capacitors is not going to sound all that great. But none the less swapping different opamps will still change the sound output on whatever platform you are using.. It is getting to be a software manipulation as a primary sound adjustment(s) before conversion to analog output.
  
 NJM4556 is a luxury compared to an older JRC5532D even though both sound pretty good in their own rights. OPA2134 is passe, was always kinda dark sounding. I have a 5.1 card and system but rely on stereo phones most of the time. Also have  Klipsch 4.1 and 5.1 subs (both have BASH circuitry) with upgraded larger Klipsch satellite speakers (Klipsch's 1" horns are really nice) but use the 4.1 sub in a stereo configuration...some fun when the bass kicks in. The 5.1 sub is outright scary.
  
 I see a few retail platforms built around the MUSES (I would only use them in the buffer position)  and also for the LME49990MA. (IMHO is a superior opamp).


----------



## backspace119

I built a CMoy recently and have a quality opamp on order (BB opa2132p) in the meantime, I have an opamp from ratshack sitting in it and ive done plenty of testing with it. (TL082C) I can report that its not bad for the money (like $2 i think) but you do get what you pay for. Both of the ones I got have had issues with DC offset (I will be resoldering the entire dang board today because I'm worried that it might be me to some extent) but as for quality.....they arent terrible. With a bass boost circuit added they gave some nice, clean, amplified bass (in the channel without the offset as I wouldn't dare plug my babies into a 54mv (104 after bass boost) offset)  Honestly these should only be used in situations where you want to test the circuit. They don't generally oscillate and they have a low quiescent current. But if you do end up doing any listening to these MAKE SURE to check DC offset first and also make sure you feed these a hefty 18v at least to prevent clipping (in a cmoy with no output stage. if you have an output stage then I cannot help you as I have not tested them with one)
  
 I am interested in what the community thinks the current best dual opamp is....(I'm new and I'm not sure which Opamp is generally accepted as supreme)


----------



## razzz42

I was working on a Klipsch 4.1 control pod (there are two models, the older V2.400 has a different layout). I have (3) 4.1 systems that needed certain upgrades due to overheating, some resistors, a zener and sometimes capacitors on the sub panel but this is first time a control pod has given me problems. Works but (even on cold start up)  has a faint scratchy sound with a occasional click or small pop. It fades in and out, disappears for a few seconds then comes back to haunt in the background through the sub and front speakers (I am not running rears). Volume and sub knobs only increase or lower the 'noise' volume. I tried heating the board up, spray cold air from a can, jabbing at the components, nothing affected the noise. Checked for obvious discolored solder pads, and bumt capacitors signs. Used an infrared thermometer gun to check for hot spots, nothing outstanding.  It's the controller board because a different controller works just fine. Wiring blocks and leads out are okay.
  
 On board it has (2) NJM 5532D for the front and rear speakers and (1) TL082CN for the sub/lows output so I replaced the TL082CN with a DIP socket and plugged in other op-amps. Didn't help the phantom noise.
  
 Now this socket position is for the lows so all my dark op-amps work really well. Like NJR/JRC OPA 627AU (single channel needs an adapter board) sounds really good with a nice thump. TI/BB 2134AP sounds good too on the lows. Muses01 wasn't to bad just a hair bass lite but clear. LM 4562N a bit flat but the bass was true (no exaggeration). AD 8066AR (dual channel but needs a DIP adapter board) slams, very hard hitting, overpowering. The stock TL082CN sounds good but you have to up the gain knob to a small sweet spot, if higher it begins to distort or just runs the lows all together at once. LME49990MA had a good strong clear sound across the entire range but was neutral when it came to the bass. Need those in the NJM 5532D places.
  
 Anyway, the stock NJM 5532Ds have (4) ceramic capacitors on the backside of the board. Not sure what Klipsch was trying to do. Here's a schematics link. The link says, "The capacitors across the inputs of U1 and U2 are not part of the PCB, and are tacked onto the op-amp pins. It apparently helps eliminate oscillations."
  




  
 [Edited for wrong link]


----------



## Mad Max

I'd clean up that awful flux mess.
 Flux can become conductive sometimes and cause shorts and problems.  Cleaning it up might even be the solution to your issue.


----------



## razzz42

mad max said:


> I'd clean up that awful flux mess.
> Flux can become conductive sometimes and cause shorts and problems.  Cleaning it up might even be the solution to your issue.


 
 That is non-conductive cement holding the ceramic caps in place. I am wondering if changing the stock op-amps (the caps are jumped across some of the op-amps legs) to a more recent design that newer op-amps wouldn't need the caps at all??


----------



## Mad Max

razzz42 said:


> That is non-conductive cement holding the ceramic caps in place. I am wondering if changing the stock op-amps (the caps are jumped across some of the op-amps legs) to a more recent design that newer op-amps wouldn't need the caps at all??


 
  
 Just make sure they aren't opamps with tremendous bandwidth as the circuit is designed for low-speed opamps.


----------



## UnknownAX

The opa2107 and ad823 should work fine in a unity gain circuit that's using jrc4556 and opa2134, shouldn't they? I can't find any problems comparing their datasheets. (Except that the 2107 will need a higher supply voltage but that isn't a problem.

I'm also unsure about buying the opamps from eBay/China, but I don't really have any options. What puts me off though, is that every opa2107 seems to have different markings and most of them don't have the "gap" that indicates with way the opamp is placed. I thought it isn't worth it to fake any "cheap" opamps, but....
The 2107's cost like 2.5€ which seems a little too low. I'd prefer an US seller but none of them has the opamps I want.


----------



## razzz42

unknownax said:


> The opa2107 and ad823 should work fine in a unity gain circuit that's using jrc4556 and opa2134, shouldn't they? I can't find any problems comparing their datasheets. (Except that the 2107 will need a higher supply voltage but that isn't a problem.
> 
> I'm also unsure about buying the opamps from eBay/China, but I don't really have any options. What puts me off though, is that every opa2107 seems to have different markings and most of them don't have the "gap" that indicates with way the opamp is placed. I thought it isn't worth it to fake any "cheap" opamps, but....
> The 2107's cost like 2.5€ which seems a little too low. I'd prefer an US seller but none of them has the opamps I wan


 
 Looks like current/update packaging for the OPA2107AP, no half moon indent, just an indented circle.
  
 Mouser has them, kinda expensive. Here
  
 eBay has the newer and older packaging. Here and Here For about $3.50 or $8.25 apiece, what could possibly go wrong? China is not totally backwards anymore, I never had any problems other than shipping times maxs 2 weeks tops but when I can I prefer Hong Kong based sellers.
  
 Seems in retail settings or mass manufacturing products, you can work with and get away with swapping out most any opamp for another.


----------



## tan1415

Is an op-amp an amplifier?
I always thought opamps works like a pre amp(minus dac) in stereo. Just color the sound.
But to really power the sound you will need a power amplifier.

Asking this question because of a motherboard the gigabyte g1 sniper b5.
It has interchangeble op amps and a headphone amp. But if I read the information correctly, they are not connected.
The op amp plays from rear jack.
The headphone amp from front jack.


----------



## zilch0md

Those LT1028ACN8s sound tempting for use as buffers, but I've had my sights set on the Muses 02 for a long time and now, Mouser.com has them in stock, so I've finally ordered a pair of them.  
  
 With tax and shipping it came to $166.87 for two opamps. Ouch!  I bought the Schiit Vali for less than that.
  
 But I _*must*_ find out what they sound like!


----------



## blasjw

zilch0md said:


> Those LT1028ACN8s sound tempting for use as buffers, but I've had my sights set on the Muses 02 for a long time and now, Mouser.com has them in stock, so I've finally ordered a pair of them.
> 
> With tax and shipping it came to $166.87 for two opamps. Ouch!  I bought the Schiit Vali for less than that.
> 
> But I _*must*_ find out what they sound like!


 
  
 Ouch!  Too bad NJR doesn't offer samples.


----------



## SpudHarris

zilch0md said:


> Those LT1028ACN8s sound tempting for use as buffers, but I've had my sights set on the Muses 02 for a long time and now, Mouser.com has them in stock, so I've finally ordered a pair of them.
> 
> With tax and shipping it came to $166.87 for two opamps. Ouch!  I bought the Schiit Vali for less than that.
> 
> But I _*must*_ find out what they sound like!




Mike, I've invested in another 01 and 02 so will have a pair of each to try in the PB2 soon. I really rate the PB2, I can't wait to try the Muses in it....

I was listening with balanced LCD3 last, the PB2/DB2 sounds BIG, HUGE in fact with a quad of AD743's and stacked buffers. With eyes closed you would be forgiven for thinking it was a decent desktop rig costing at least twice it's retail. It punches way above it's weight. Probably the best bang for buck ever.


----------



## zilch0md

Oh no! I need to buy more op-amps? Noooooooo....! 



LOL

When you get the 2nd Muses 02, please tell me what you think of LME49990 in I/V with Muses 02 as buffers - to the HD800. That's what I'm dying to try and would really like your opinion.



Mike


----------



## SpudHarris

Will do pal. Never really thought of using them as buffers but will give it a go. What are you expecting buddy Audio Nirvana per chance?


----------



## zilch0md

LOL Nigel!
  
 Yes, I'm hoping for exactly that!  
	

	
	
		
		

		
		
	


	



  
 Actually, it's about my last shot at finding a solid state amp that will justify keeping the HD800, without spending a lot of money.
  
 Keeping this as brief as possible...
  
 I bought the HD800 without having any particular amp in mind, but I knew that it has a reputation of being finicky.
  
 Even after burn-in, I didn't like the HD800 with anything I own, nor anything I've borrowed - all solid state - except for finding it "tolerable" with my TBI Audio MG3 > TBI resistor network that imposes 15.8 dB attenuation to kill hiss from excessive gain in the MG3.  For me, the problem has been not enough bass and too much treble, but I love the detail, imaging and sound stage of the HD800.  It's like a girl with a beautiful face and crooked teeth.  I want to take my HD800 to the orthodontist!
  
 So, several people suggested I try the Schiit Vali hybrid amp > HD800 and as of this writing, the Vali is the best HD800 solution I've heard for handling any type of recording (without spending a ton of money on a proper tube amp and going OCD with rolling tubes) - but, I've come to realize that the Vali is intrinsically noisy and puts a bit of a sheen on everything, even though I really like the FR it yields with the HD800, and even the detail it preserves.
  
 Then I got the Beresford Bushmaster MkII DAC/amp (which is known for being warm and having great bass), where I liked it not quite as much, so I tried feeding the Bushmaster MkII analog out to the TBI MG3 > resistor network > HD800, which was getting real close to being ideal, until I got some HD650 and realized just how little bass I was hearing in the HD800, even still, and...  how much dynamics and even resolution were being lost with the attenuated TBI MG3. 
  
 Going back to using the Bushmaster MkII DAC + amp directly into the HD800, I've resorted to creating an HD800-specific playlist - with recordings that don't demand much bass performance, nor have anything shrill happening in the treble.  These recordings, like solo guitar, or guitar + vocal, or pretty much anything acoustic - when played through the Bushmaster MkII - directly into the HD800 really show off both the Bushmaster and the HD800, with no ill effects.
  
 My last hope, short of buying an Eddy Current or Cavalli tube amp (and I'm not even interested in something more affordable like the Woo WA6SE, as I've heard that they color the sound to "fix" the HD800 while also degrading some of the resolution), is to make my iBasso PB2 as warm as possible - it's the only amp I can tweak in this way.  The goal is to "fix" what's wrong with the HD800, without degrading what's right.
  
 I've found that I can pretty much emulate the sound of the Bushmaster MkII's amp section by equipping the PB2 with OPA1612s in I/V and dummy buffers, so that gives me more power than the Bushmaster MkII's amp section outputs, but I want treble warmth and more bottom-end energy, with as little impact as possible to the micro-details and separation that are rendered so nicely by the Bushmaster MkII > HD800. 
  
 Just from reading, I have a hunch that I will get closer to what I'm looking for, if not Audio Nirvanna, with this chain:
  
 Resonessence Concero (as USB-to-SPDIF converter) > Bushmaster MkII analog out (bypassing its amp) > iBasso PB2 equipped with LME49990 in I/V and Muses 02 as buffers > balanced out to HD800.
  
 Of course, I'll probably be rolling some other combinations, as well, including Muses 02 in I/V with dummy buffers and OPA1612 in I/V with Muses 02 as buffers...
  
 I can't _believe_ I'm about to start rolling opamps again after keeping a lid on the PB2 for so many months...
  




  
 Which all begs the question... "What's your favorite rig for use with your HD800 (PB2 or otherwise)?"
  
 Thanks!
  
 Mike


----------



## SpudHarris

zilch0md said:


> LOL Nigel!
> 
> Which all begs the question... "What's your favorite rig for use with your HD800 (PB2 or otherwise)?"
> 
> ...




Oh man, I'm not going to help matters.... I use the Icon HP8 with the HD800's. I'm told many people find synergies but I think unless you have a boutique stash of tubes you may struggle to find the ideal sound. I started collecting 6SN7 tubes ages ago when I bought a WA6. I kept most tubes as I thought I may get back into them again one day and most of my collection were as rare as hens teeth.

I will definitely check out the combination you desire and report back but I don't have a balanced cable for the HD800 so YMMV.

You aren't rolling aimlessly now, you have got to the fine tuning stage. I hope that you find what you are looking for as the HD800 is a truly superb phone and you will regret it if you let it go. I bought mine used (here on Head-Fi) and the guy I bought it of kicked himself and bought them again within a month 

Take care - Nigel


----------



## zilch0md

Thanks Nigel!  I knew you had some tube gear, but I was hoping you had a favorite PB2 configuration for the HD800, too.  
	

	
	
		
		

		
		
	


	



  
 Your sngle-ended HD800 cables should sound pretty much the same on the PB2, except for running half the power, so don't worry about that.  I already had a balanced Toxic Cables Silver Poison for HD800, purchased used, for use with my MG3 speaker amp + resistor network.  The Silver Poison is terminated with a 4-Pin XLR, so I've ordered the CB11 adapter from iBasso to adapt the PB2's Hirose connector to 4-Pin XLR.  
  
 I hear you about not selling the HD800.  It has some very special traits, but they come with negative traits, as well (with most amps).  I bought mine new for only $890 during a 30-minute window of opportunity at Amazon this past December 19th. Since then, because of the HD800, I've bought balanced cables, the Schiit Vali, and now the Muses 02 (x2) and CB11 - all because of the HD800 - trying to keep the wallet as closed as possible while "fixing" the HD800, but something tells me I'm going to end up buying one of every solid state amp that's allegedly good for the HD800 (i.e. Matrix M-Stage, Violectric V200, etc.) before I cave in and get a >$1k tube amp.  I really don't want to go to tubes, though.  There comes a point where I'd be better off just selling the HD800, as I get plenty of enjoyment from my much less finicky LCD-2, but I would be haunted by the inability to enjoy its detail, separation, and sound stage.  
  
 If you want, just wait for me to try the LME49990 + Muses 02 as buffers.  If that, or some other combination, works well with the HD800, I'll come running for your second opinion.  
	

	
	
		
		

		
		
	


	



  
 Thanks,
  
 Mike


----------



## zilch0md

A post I made to the PB2 thread regarding how Mouser.com packaged and shipped my Muses02 (x2):
  
 http://www.head-fi.org/t/528149/ibasso-pb-2-pelican-fully-balanced-portable-db-2-dac-hiflight-recommended-op-amps-page-16/1050#post_10280548


----------



## ClieOS

zilch0md said:


> A post I made to the PB2 thread regarding how Mouser.com packaged and shipped my Muses02 (x2):
> 
> http://www.head-fi.org/t/528149/ibasso-pb-2-pelican-fully-balanced-portable-db-2-dac-hiflight-recommended-op-amps-page-16/1050#post_10280548


 
  
 I received mine in similar (plastic bag) package as well, but from akizukidenshi.com (MUSES official distributor in Japan). I don't think those pretty boxes from Audiotrak has anything to do with MUSES directly. It is probably just a nice box Audiotrak happens to have at their hand.


----------



## SpudHarris

Well that's me told!


----------



## zilch0md

spudharris said:


> Well that's me told!


 
  
 No problem Nigel. 
	

	
	
		
		

		
			




  
 I think it was perfectly reasonable to assume that since Gyrocom is an official distributor for Audiotrak, that the jewel boxes were coming from Audiotrak.
  
 If that wasn't your assumption, it was certainly mine.  
	

	
	
		
		

		
		
	


	



  
 So, I was disappointed at first, but I'm now convinced it's just a nice add-on from Gyrocom.
  
 Mike


----------



## SpudHarris

P4 with Muses 02 in G/VG dummy buffers and LME49990 in L/R.


----------



## zilch0md

Cool, Nigel!  
  
 Me like dummy buffers!
  
 As I've written before, I have yet to find an op-amp that doesn't degrade resolution, at least a little bit, when used in the PB2 as a buffer instead of using dummy buffers. For some tastes, with overly analytical headphones, the "smoothing" caused by buffers might be desirable, of course - not to mention the current gain that can be had with "real" buffers.
  
 I''m not familiar with the P4, so I'm confused, from reading your post, that there seems to be three places to mount op-amps:
  
 L/R - where you've mounted LME49990
  
 Buffers - where you're using dummies
  
 G/VG - where you're using Muses02s  <--- What is "G/VG" ?
  
 (The PB2 only has L/R and Buffers, so this has me scratching my head.)
  
 Thanks,
  
 Mike


----------



## ClieOS

Ground / Virtual Ground?


----------



## Mad Max

Yes.


----------



## SpudHarris

zilch0md said:


> Cool, Nigel!
> 
> Me like dummy buffers!
> 
> ...




The P4 is a 3 or 4 channel Amp. The sound is really customiseable as all 3 rows of sockets can change the sound in one shape or form. Knowing how you get with rolling I would suggest you don't buy one as you would never sleep  

The sound with this configuration is amazing but the turn on thud is a bit scary.


----------



## SpudHarris

spudharris said:


> The P4 is a 3 or 4 channel Amp. The sound is really customiseable as all 3 rows of sockets can change the sound in one shape or form. Knowing how you get with rolling I would suggest you don't buy one as you would never sleep
> 
> The sound with this configuration is amazing but the turn on thud is a bit scary.




Sockets are L/R > Buffers > Ground/Virtual Ground...


----------



## zilch0md

Thanks Nigel,
  
 Opamps for Virtual Grounds are explained here (I think):  http://www.electronicspoint.com/op-amp-virtual-ground-t103836.html
  

  
 Mike


----------



## BucketInABucket

What's the difference between the MUSES01 and the OP627? I see Cesar offering both options for his new Portaphile 627 Micro amp and am wondering what to do.


----------



## gibosi

bucketinabucket said:


> What's the difference between the MUSES01 and the OP627? I see Cesar offering both options for his new Portaphile 627 Micro amp and am wondering what to do.


 
  
 This posting might be of interest to you:
  
 http://www.head-fi.org/t/432749/the-opamp-thread/4590#post_10164689


----------



## BucketInABucket

gibosi said:


> This posting might be of interest to you:
> 
> http://www.head-fi.org/t/432749/the-opamp-thread/4590#post_10164689


 
 Alright, thank you very much.


----------



## NCSUZoSo

Well I decided I will be selling my genuine MUSES01, I am most likely going to put it on Ebay unless someone says something/PMs.  It's easy to tell the real ones in your hands because the legs are easy to bend unlike a lot of others that are stiff and the logo is obviously perfect.


----------



## motorwayne

spudharris said:


> Well the good news is that these OPA2111AM's are the real deal gold plated legs and all. The little adapters that come with are good when you need a quick way to use a TO99 in a DIP socket, no soldering or Brown Dog required.
> 
> Anyone interested in getting one of these? I already have two on Brown Dogs as spares but can order more. You can have them for same price as me (£6) + shipping. These retail for £39.00 + VAT each
> 
> ...


 
 I want to do this to my Titanium HD but am struggling to find the amps for a good price, and the adapters anywhere at all. What are those white and green ones there?


----------



## SpudHarris

Don't worry...
  
 I can sort you out dependant on how many you are after. I still have a few left over, both adapters and OpAmps so let me know what you need and we can work something out.
  
 Cheers
  
 Nigel


----------



## motorwayne

spudharris said:


> Don't worry...
> 
> I can sort you out dependant on how many you are after. I still have a few left over, both adapters and OpAmps so let me know what you need and we can work something out.
> 
> ...


 
 Actually sorted it out in the end. Local company bringing the bits in for me. Bit more expensive but what the heck...I'm a mad gamer that likes to immerse myself in the sound of the game.


----------



## FritzS

spudharris said:


> Well the good news is that these OPA2111AM's are the real deal gold plated legs and all. The little adapters that come with are good when you need a quick way to use a TO99 in a DIP socket, no soldering or Brown Dog required.
> 
> Anyone interested in getting one of these? I already have two on Brown Dogs as spares but can order more. You can have them for same price as me (£6) + shipping. These retail for £39.00 + VAT each
> 
> ...


 
  
 I ordered a OPA2111KP (PDIP) test sample now. I will test them in my GSP Audio Solo headphone amp.
  
Gives a single channel version of the OPA2111 too  - PDIP or TO99?
  
From where you get the white adapter socket - TO99 to PDIP?


----------



## SpudHarris

fritzs said:


> I ordered a OPA2111KP (PDIP) test sample now. I will test them in my GSP Audio Solo headphone amp.
> 
> 
> [COLOR=525252]Gives a single channel version of the
> ...




They came with the TO99's. You just push and the legs just split into a DIP footprint (with a little help)...


----------



## zilch0md

That's cool.


----------



## FritzS

I get an OPA2111 (KP - Dual LN DIFET, 8 DIP) sample and put them into my headphone amp GSP-Audio Solo DIP socket.
 Before I had tuned them with an LME49720HA OPA (original are an AD823AN)
  
 In my second headphone amp WNA MKII I use two *OPA627*  now.
 The OPA627 is an Precision High-Speed Difet® Operational Amplifier and have an slewrate from 55V/usec
 The* OPA2111* is an Dual Low-Noise Difet® Operational Amplifier and have only an slewrate from 2V/usec
  
 I wonder thats the OPA2111 sounds so good too, despite its low slew rate.
 It seemed to be the better choice that the modern high end LME49720HA
  
 Modifications are my passion 
	

	
	
		
		

		
		
	


	



  
 In all the time I had done this, mostly I preferred FET input OPAs before BJT input OPAs.
  
 TI offers other high fidelity JFET input audio dual op amps like OPA2134, OPA1642 and OPA1652, or bipolar input audio duals like OPA1602, OPA1612 and OPA1662.
  
 What are your experience between OPA2111 and OPA2134 - the others from TI are only SOIC packages. Another way is to use an adapter - two 8 DIP to one.


----------



## vixr

fritzs said:


> I get an OPA2111 (KP - Dual LN DIFET, 8 DIP) sample and put them into my headphone amp GSP-Audio Solo DIP socket.
> Before I had tuned them with an LME49720HA OPA (original are an AD823AN)
> 
> In my second headphone amp WNA MKII I use two *OPA627*  now.
> ...


----------



## motorwayne

Just checking I have these amps in the right way.
  
 The pin that sticks out is pin 8 which based on the DIP8's that were in the slots should be in the right place...
  
 Any pointers before I flick the switch and fry the board 
  
 Cheers
  
 motorwayne


----------



## zilch0md

There should be a dot or a notch in the socket to which the notch at one end of the op-amp can be aligned.


----------



## motorwayne

Yeah, didn't see that but ended up just matching up to the diagram from farnell. Booted up all good...sounds a lot better, richer.
  
 That being said, with these babies in, I can have the plastic shield piece over that area...wonder if it makes a difference to interference?
  
 Any ideas from other Tit HD owners?


----------



## DutchGFX

I'm designing a Gainclone for Headphones, just as a simple fame, since it's my first time designing. I am going to use a gain of 6, but I can't seam to select my Opamp. I'm not going to use the LM3875 since it's so high powered. I was thinking maybe LME49990 or OPA827. Any other ideas? 8 pin DIP preferred, but not necessary. I really have no idea what Opamp to use, so any help would be great, Thanks!

Here is my schematic for the simplest gainclone around 

I'm assuming this will work for SE use, I'll just share the ground between the two amp boards.


----------



## DingoSmuggler

dutchgfx said:


> I'm designing a Gainclone for Headphones, just as a simple fame, since it's my first time designing.


 
 So you're designing a cmoy(variant)? What design goals are going to make this any different than what's already available?


----------



## DutchGFX

I suppose it's a CMOY. I didn't really think about that lol. I might add a MOSFET follower on later. I'm planning on running it from +-15V supply rails. I have never designed an amp before, so I figured I would start with the simplest design possible; the standard non-inverting Opamp. I plan to share the ground between the two channels


----------



## Avro_Arrow

OPA2134 - easy to work with, better chance of success.


----------



## razzz42

So...I was working replacing the stock front channel JRC5532D opamp in a Klipsch 4.1 preamp after already finding and upgrading the stock sub output ST TL082CN opamp with an AD 8066AR and all replacing all 6 resistors on the little board with Nichicon 10uf 25 volt (aluminum audio grade, mainly due to height restriction when closing it back up).
  
 After searching for a replacement for the 5532D that would make it worth my while to bother with it, I decided on a dip 8 LME 49860NA. I don't know if it is the dual channel version of the single channel LME49990 or something close but reviews were okay with it. Remove some cement and then desoldered the 5532D and its accompanying (2) resistors soldered to the backside legs (inputs?), apparently helps eliminate oscillations. Hoping the new 49860NA  opamp would not need them. Went well, installed a DIP 8 socket. Left the other stock rear channel 5532D in place until the results are in. Defluxed everything and recoated with spray silicone. I figure I can do as good a job as any Chinese 10 year old slave laborer. Went to my mess of opamps and thought I picked out one of the two new 49860NA  but no by mistake had a LM 4562NA (didn't even know I owned one) what are the chances?
  
 Install it, turned it on and I go, "What a waste of time and money this was." Lows were missing, highs were clear to the point of being shrill, mids nowhere to be found. If it needed breaking in, I doubted it would ever recover. Having the DIP 8 socket installed, I begin digging for some old standby opamps to checkout and discover I have two 49860NA in the mix. Go check the occupied DIP socket and confirm it is a 4562NA sitting in it and grab the eBay $5 special yellow handled opamp tweezer/removers and install the 49860NA and turn the system back on.
  
 The difference is between night and day. Clarity with clean highs and lows and mids mixed right in between, nothing really stands out unless there is a flute playing or bass drum hit. Vocals are clear and true. If I am missing warmth or am hearing sibilance, hard to tell, may be the recording(s) but the great detail adds to the separation (staging).
  
 After a year or two, I am still getting use to the clarity in lows. No longer am I hearing thuds and booms but musical bass notes by using decent opamps plus at low power points (don't have to turn it up for lows). Also I find movies or audio tracks that use AAC audio are the most compact and best at reproducing sounds. I have to use Foobar for playing AAC back (added the plugin? Can't remember) but can't edit the properties i.e names, dates, tracks but there is absolutely no degradation when I rip an audio track from a movie or off You Tube now (mp4 files). I can still convert to other formats via Foobar with some warning message that the new music file won't be any better except a larger file which it always is compared to the original AAC file.
  
 Testing mostly with a CD album, Title : Morph The Cat (2006) Donald Fagen. Has good ranges and some tight bass, well recorded. Ripped:  Baby, It's Cold Outside from the ending movie soundtrack ELF (2003), kept it in its AAC format, sounds better than the CD movie sound track album.


----------



## zilch0md

That was a fun read!


----------



## P701

razzz42 said:


> Install it, turned it on and I go, "What a waste of time and money this was." Lows were missing, highs were clear to the point of being shrill, mids nowhere to be found. If it needed breaking in, I doubted it would ever recover. Having the DIP 8 socket installed, I begin digging for some old standby opamps to checkout and discover I have two 49860NA in the mix. Go check the occupied DIP socket and confirm it is a 4562NA sitting in it and grab the eBay $5 special yellow handled opamp tweezer/removers and install the 49860NA and turn the system back on.
> 
> 
> 
> ...



 

Not even sure if this is a sarcastic or a "true hifist" message...
You do realise that LM4562 is pretty much same as LM49860NA, but with higher maximum voltage range and manufacture year?
If you actually managed to find differences, either of those opamps is probably fake and thats why it might sound a little different.


----------



## razzz42

p701 said:


> Not even sure if this is a sarcastic or a "true hifist" message...
> You do realise that LM4562 is pretty much same as LM49860NA, but with higher maximum voltage range and manufacture year?
> If you actually managed to find differences, either of those opamps is probably fake and thats why it might sound a little different.


 
 Here is some older discussions at DIY about this opamp lineup which I guess includes can variations. Seems the 4562 is a bit temperamental and could suffer from oscillations in the wrong environment which I am trying to avoid like with the 5532D and confirms the 49860 might be somewhat weak or not warm in the mid range but to my ears is crystal clear with the highs, for the lows I have an AD 8066AR handling those duties.
  
 The 49860NA is labeled LME, 'E' for enhanced, whatever that means. I admit I have many opamps from Chinese/Hong Kong and anything is possible involving knockoffs. I also have a sub with BASH surround circuitry that will amp up the preamp input signal to an audiophile level where I can hear subtle differences via some decent speakers. And my starting point is a PCI sound card AUDIOTRAK Prodigy HD2 ADVANCE DE with LME 49990 on adapters buffered by LT1028ACN8 on an adapter. Checking my old notes, I have the LM 4562NA down as 'flat but true across the range' from previous sound card testing. It could be the 4562 just didn't like the position it was put in this time around.


----------



## zachchen1996

Anyone interested in a _pair_ of _*OPA627SM*_ op-amps for $100?
  
http://www.head-fi.org/t/718227/interest-check-pair-of-opa627sm-op-amps


----------



## NCSUZoSo

I've tried to get rid of a single genuine MUSES01 (obo $60) in this thread and it's like nobody trusts buying from people in this thread,


----------



## DR650SE

Hello all,

I really know nothing about opamps but would like to learn. I purchased the Leckerton Audio UHA 6S.MKII amp and it came with 4 sets of opamps. I have attached pictures of them. It appears they are the following opamps.

OPA209
AD797ANZ
LME49990MA
OPA627AP

Would anyone be able to tell me what to expect from them, or what characteristics they are know to have? Im still knew to the audiophile thing. I havn't spent much time with them, and so havn't noticed much differance. Im using the OPA627AP in my amp right now with my iMod and Beyerdynamic DT 880 250ohm cans. Thanks for the education guys! Im doing a lot of learning via the search function as well.

Sorry for the quality, the pics were taken with my camera phone


----------



## jcx

there's hope if you're really interested in learning - hanging with your buds in this thread, looking for positive social feedback however...
  
 if subjective evaluation is your focus then http://www.linearaudio.net/images/LA%20Vol%202%20Yaniger(1).pdf should be required reading - and practice - you really need 2 complete "blueprinted" (trimmed to exact same gain/frequency response, at least better than 1%, ~ 0.1 dB) systems/circuits to do real listening tests - and a blinding protocol
  
 it also wouldn't hurt to learn enough electronics to recognize different op amp applications in audio circuits, have schematics of the equipment you want to mod - know the circuit conditions like source, feedback and load impedance, how these change "optimum" op amp specs
  
 learn about construction details of PCB layout, op amp bypass, gnd planes/power routing (or lack of quality of same) which can rule out many fast op amps being stable when rolled into layouts that work for order of magnitude slower chips
  
  
 hopefully my pointing this out every few thousand posts, in response to new participants, isn't going to derail the thread


----------



## nikongod

jcx said:


> hopefully my pointing this out every few thousand posts, in response to new participants, isn't going to derail the thread


 
  
 Its still rolling along same as it ever has...


----------



## zilch0md

Anybody want to trade a pair of Muses 01 for my pair of Muses 02?
  
 http://www.head-fi.org/t/724192/i-want-to-trade-my-two-muses-02-op-amps-for-your-two-muses-01-op-amps-even-trade


----------



## Nintendo Maniac

So I was looking for an op amp that would almost be an opposite to the LME49990 - not opposite as in "it'd sound crappy" ,but like where "cold and analytical" is the opposite of "warm and embracing". 
  
 For reference I plan on using said op amp on a Xonar DS; it's stock op amp was a NE5532P and I replaced with an LME49990 (2x on a DIP8 that is).  Also, I don't want anything like the NE5532P.   It just seemed particularly unnatural-sounding to me or something.
  
  
*EDIT:* Before I got the LME49990 I had read that it's like turning up the contrast on your TV to maximum.  By comparison, I've found comments that the LT1122 is very smooth, which to me sounds like an candidate for being an opposite of the LME49990.
  
  
  
 I also noticed that there's no wiki or database for op amps or anything as far as I can tell.  For there being something like this huge thread here, I'm surprised there's nothing that has a lot of the info in a nicely organized manner, such as the generally accepted characteristics of each op amp (slow/fast, wide/narrow, warm/cold, etc).


----------



## zilch0md

Wait for other opinions before spending the money, but I think you would enjoy the Muses 02. As to a database - the "data" so subjective, even short lists are hard to find.


----------



## SpudHarris

I have the LT1122 but as I haven't rolled anything for a while I can't really comment. I will have a listen this evening....


----------



## Nintendo Maniac

zilch0md said:


> I think you would enjoy the Muses 02


 
  
 There's no North American seller on Ebay, so no go.
  
 ...also it's a bit out of my price range.  Consider that my Xonar DS is the most expensive audio equipment I own, and it was _used_ ($30).


----------



## SpudHarris

Can you solder?


----------



## Nintendo Maniac

I would prefer not to.  I probably _could _if I really wanted to considering I've done crazy things like removing the IHS from a CPU with a razor blade (done it on 4 CPUs and all were a success).
  
 Also my father soldered all the time in his youth and even does some today still, so I'm not particularly unfamiliar with it.


----------



## SpudHarris

What form do they need to be? 2 x singles or 1 x dual?


----------



## Nintendo Maniac

Let's make it simple, this is the exact LME49990 module that I'm using:
 http://www.ebay.com/itm/190999739495
  
 So regarding the LT1122, I believe this would be the right form-factor:
 http://www.ebay.com/itm/150859013571
  
  
 (you know when you've been doing too much with CPUs and motherboard when you keep typing LGA49990 instead of LME49990 >_>)


----------



## SpudHarris

Right so a dual. I will see what spares I have...


----------



## Nintendo Maniac

spudharris said:


> I will see what spares I have...


 
  
 Are you implying that you're considering selling some of your spare op amps?  Your location says the UK though, and I'm in northeast Ohio.  Therefore, wouldn't shipping easily cost more than the amp itself?


----------



## leeperry

nintendo maniac said:


> So I was looking for an op amp that would almost be an opposite to the LME49990 - not opposite as in "it'd sound crappy" ,but like where "cold and analytical" is the opposite of "warm and embracing".


 
  
 OPA2107 / 627 & 2132 come to mind but all cheap 627's are fake, gotta buy them from an authorized dealer.


----------



## Nintendo Maniac

leeperry said:


> all cheap 627's are fake, gotta buy them from an authorized dealer.


 
  
 Very aware of this, I read several of your own old posts stating this very thing.
  
 Speaking of OPA6xx I read another post stating that the OPA602BP seemed kind of between the LGA49990 and the LT1122, so I was thinking of perhaps getting the LT1122 now and then getting the OPA602 afterwards.
  
 As for the OPA2107 and OPA2132, I had indeed researched both, and both seem to have several North American ebay resellers that are below $10.
  
  
*EDIT: *I will admit though, one thing I had liked about the LT1122 was that it didn't seem to be very common and several people said it was the only LT op amp they liked, so I kind of wanted to possibly get one of those while such a thing is still possible (the OPA op amps seem extremely plentiful by comparison).
  
*EDIT 2: *Hmm, it would seem that the OPA2107 isn't quite as plentiful as some of the other OPA amps, particularly DIP8 dual version.  The following seems to be the only "Buy it Now" North American listing for a single unit of a DIP8 dual OPA2107 under $15:
 www.ebay.com/itm/181446016408


----------



## SpudHarris

Hey, karma points is all I need 

Drop me a PM with your address and I will drop something in the mail...


----------



## SpudHarris

leeperry said:


> OPA2107 / 627 & 2132 come to mind but all cheap 627's are fake, gotta buy them from an authorized dealer.




Hey you!! How you doing? Are you still loving the OPA602CM?


----------



## Nintendo Maniac

spudharris said:


> Drop me a PM with your address and I will drop something in the mail...


 
  
 ...lolwut, head-fi's acting up again where I'm not getting instant email notification of replies.  And no, it's not in my email's spam folder either.
  
 Anyway, I will PM you momentarily.
  
*EDIT:* PM sent.


----------



## Nintendo Maniac

Super-duper apologies for a double post, but I was wondering what people use for storing their op amps?  I've personally discovered that a CPU clamshell for PGA processors with the foam for the pins works great for DIP8 op amps:


----------



## leeperry

nintendo maniac said:


> I read another post stating that the OPA602BP (..) it would seem that the OPA2107 isn't quite as plentiful as some of the other OPA amps


 
  
 Yeah, 602BP is quite fun too. Personally I remain quite wowed by 1641, it's a new design and it sounds really great. TI advise it for high-end BD players and it's very cheap so it's well worth the 10 mins to solder two onto an adapter.
  
 2107AP can sound very bassy and thick depending on the application, I've been quite impressed when used as I/V within PCM1792A designs.
  
 The only opamp from LT that was specifically designed for audio is LT1028 AFAIK, LT1363 is still worth a shot though IME.
  
 Of course it's all based on blind rolling so YMMV, it's just sheer fund to solder chips, pop them in and instantly hear the result of your work......it's lego for bored audiophiles, plain fun really


----------



## leeperry

And let's not forget OPA827, many ppl rave about it as one of the very best chips for DAC filtering and sometimes it really does the magic with stunning resolution and highly textured deep bass IME
	

	
	
		
		

		
		
	


	



  
 Several cheapo DAC's shipping with OPA2134 and the likes can really benefit from 827 IMO: http://www.ti.com/product/opa827


> After i replace opa2107 with this OPA827 in a dual - single adapter to my DIY amplifier . I keep listening till around 40-50 hours and i feel that my amp sound very richer and smoother when compare to the old opa2107


----------



## Mad Max

nintendo maniac said:


> Super-duper apologies for a double post, but I was wondering what people use for storing their op amps?  I've personally discovered that a CPU clamshell for PGA processors with the foam for the pins works great:


 
  
 I use the iBasso cases from opamp adapters I've ordered from them in the past.  The plastic boxes with foam that contain opamp samples from ADI are also quite good, even for DIP adapters with opamps soldered to them.


----------



## Nintendo Maniac

mad max said:


> even for DIP adapters with opamps soldered to them.


 
  
 Oh, I was specifically referring to DIP adapters actually.   I've no experience with single stand-alone non-DIP op amps, so....


----------



## Mad Max

nintendo maniac said:


> Oh, I was specifically referring to DIP adapters actually...


 
  
 Same here.  Empty adapters, DIP opamps, DIP adapters with whatever opamps, and so forth.  Excluding "discrete" opamps.


----------



## Pwn3r4Life

Is there a community chart somewhere? Like a big list of most of the op amps, as well as price, where to buy (I've heard Ebay, but I've heard don't use Ebay), and their price. That would be extremely helpful. I've heard the OPA827, OPA627, OPA-Earth, OPA-Moon, LT1355, and the MUSES 8920 are all great. But I can't find a whole lot about where to buy any of them, or information about the products themselves that isn't in the form of charts that I can't understand. Anyone care to help a noob?


----------



## Mad Max

Mouser and Digikey for opamps.
  
 Some ebay sellers tend to sell fakes, especially where OPA627 and AD797 are concerned, or they sell opamps taken from very old, heavily-used equipment and call them "new".
  
 Some more noteworthy chips: AD4898, AD8597, ADA4627-1B, OPA209, OPA1611, OPA602B, OPA1652, OPA1641, LME49860, and AD8610 (this last one is generally best in portable devices as it cannot take the voltage of full-sized equipment, generally).


----------



## Pwn3r4Life

mad max said:


> Mouser and Digikey for opamps.
> 
> Some ebay sellers tend to sell fakes, especially where OPA627 and AD797 are concerned, or they sell opamps taken from very old, heavily-used equipment and call them "new".
> 
> Some more noteworthy chips: AD4898, AD8597, ADA4627-1B, OPA209, OPA1611, OPA602B, OPA1652, OPA1641, LME49860, and AD8610 (this last one is generally best in portable devices as it cannot take the voltage of full-sized equipment, generally).



I'll do some more research and try to find one that matches my taste as far as sound signature. Natural and warm, yet slightly technical, and nothing close to bright.
That's 17 choices though, I have my work cut out for me.


----------



## leeperry

pwn3r4life said:


> I'll do some more research and try to find one that matches my taste as far as sound signature. Natural and warm, yet slightly technical, and nothing close to bright.


 
  
 Scott Wurcer(the designer of AD797) made very clear on diyaudio that opamps don't have a sound signature of their own and that blind rollers got it hard.


----------



## Pwn3r4Life

leeperry said:


> Scott Wurcer(the designer of AD797) made very clear on diyaudio that opamps don't have a sound signature of their own and that blind rollers got it hard.



So then what is the point of all these different Op amps? Can't you just measure one better than all the others?


----------



## leeperry

EE's consider blind rollers like us to be plain idiots, just so you know =)
  
 We're playing lego with highly integrated devices whose surrounding circuit is supposed to have been custom designed for them....as to why they sound different is open for debates, I'm sure MadMax will have beautiful theories to share 
	

	
	
		
		

		
			




  
 Of course some opamps aren't unity gain stable, meaning that they're not PNP by a long shot...AD797, OPA637 and LT1028 come to mind. If you roll them blindly, they will more than likely oscillate...making wooshing sounds, crackle, sound very harsh and bright and so on.


----------



## zilch0md

leeperry said:


> *We're playing lego with highly integrated devices whose surrounding circuit is supposed to have been custom designed for them....*


 
  
 LOL - That's so true and I'm all for it. 
	

	
	
		
		

		
		
	


	



  
 At least I use a thermometer to make sure nothing is overheating...  
  

  
  
 And when they do overheat, I just close the case and attach a heat sink!
  
 Tada!
  

  
 Mike


----------



## Mad Max

leeperry said:


> EE's consider blind rollers like us to be plain idiots, just so you know =)
> 
> We're playing lego with highly integrated devices whose surrounding circuit is supposed to have been custom designed for them....as to why they sound different is open for debates, I'm sure MadMax will have beautiful theories to share
> 
> ...


 
  
 Well, I do change resistors and caps as well when rollin'.  Good ol' oldschool hand-wound resistors sound best.  
	

	
	
		
		

		
		
	


	



  
  
  
  


zilch0md said:


> LOL - That's so true and I'm all for it.
> 
> 
> 
> ...


 
  
 That heatsink needs to go _directly on_ the opamp!  On the case is fine when you've got voltage regulators sinked to the case or if you want a groovy room heater.


----------



## leeperry

mad max said:


> Well, I do change resistors and caps as well when rollin'.


 
  
 How about wooden mods to those giant caps?


----------



## Pwn3r4Life

So basically, find someone who had success with an op amp in the same system you have, or just swap until it sounds great?
You guys are nuts! But I mean that in the most endearing way. I love it!
Personally, I don't want to fall into this trap. I have too much to tinker with already.
But I still don't understand why they sound different. Madmax, care to explain?


----------



## Mad Max

leeperry said:


> How about wooden mods to those giant caps?


 
  
 I would onoly use those in tube amp, ugh.  I'm not a tube man.  I like my trebles in full-HD.


----------



## Mad Max

pwn3r4life said:


> So basically, find someone who had success with an op amp in the same system you have, or just swap until it sounds great?
> You guys are nuts! But I mean that in the most endearing way. I love it!
> Personally, I don't want to fall into this trap. I have too much to tinker with already.
> But I still don't understand why they sound different. Madmax, care to explain?


 
  
 It's all leeperry's fault.
  
 Galvanic isolation of his brain allows opamps to distort to some degree, resulting in the differences that we hear.
  
 Yeah, just roll opamps until you get one that sounds best.  Taking a peek at the oapmp's datasheet helps tremendously.  You don't want to stick AD797 into an amplifier that only supplies the chip with +/-3V (797 requires a minimum of +/-5V), you probably also should not stick a 55MHz opamp into a circuit that was originally designed for an 8MHz opamp.  That faster opamp will probably oscillate to hell and back in that amplifier and will get hot enough to cook your breakfast.  Then some opamps are a little particular.  OPA1611 cannot have too much input electrical current or it will shut down according to its datasheet.
  
 This rabbit hole goes on and on and on.  =X
  
 You get the hang of it over time.


----------



## leeperry

It's essentially a hobby as it's a lot of fun to solder chips onto an adapter, pop them in and hear how things go. The only modifications non-DIY people can try is roll cables and that's it. Once you get the DIY bug, you start soldering/rolling opamps, rehouse+recable headphones drivers into wooden enclosures and so on. One step further is to roll caps but I personally haven't gotten into this (yet 
	

	
	
		
		

		
		
	


	




) and another step further is to solder a headamp from scratch.


----------



## zilch0md

mad max said:


> That heatsink needs to go _directly on_ the opamp!  On the case is fine when you've got voltage regulators sinked to the case or if you want a groovy room heater.


 
  
 That picture of a heat sink sitting on my PB2 case was a joke.  
	

	
	
		
		

		
		
	


	




  When the temps get way higher than other op-amps, I yank them, whether I can hear oscillation or not.  
  
 I do use the Raytek MT6 laser thermometer in the picture above, however, as recommended by qusp when my 4x AD797s were getting really hot used as buffers with LME49990 in my PB2 - back when I was heavily into (obsessed with) rolling op-amps in 2012.   
  


leeperry said:


> How about wooden mods to those giant caps?


 
  
 Wow, I admire his craftsmanship, but it seems like a solution looking for a problem.
  


mad max said:


> I would only use those in tube amp, ugh.  I'm not a tube man.  I like my trebles in full-HD.


 
  
 Amen!   I'm done with tube gear (because I can't afford the tube gear that has good resolution).
  
 Mike


----------



## Pwn3r4Life

Has anybody here heard of or heard the Burson Audio Supreme Sound Op-amp? The thing is pretty massive, 16x42x21 mm for dual, and fetches $70. What do you guys think? Do you guys prefer IC op-amps over stuff like the Burson Audio SS and the Audio GD op-amps? This stuff still makes almost no sense to me, but I'm giving this stock OPA a good listen before I swap in my OPA2134.


----------



## zilch0md

I've heard about them for years, but don't know anyone who has tried them. They are not ICs, but rather discrete components that, together, emulate an IC-based op-amp. (Actually, the ICs emulate the discrete components!)

Mike


----------



## Mad Max

pwn3r4life said:


> Has anybody here heard of or heard the Burson Audio Supreme Sound Op-amp? The thing is pretty massive, 16x42x21 mm for dual, and fetches $70. What do you guys think? Do you guys prefer IC op-amps over stuff like the Burson Audio SS and the Audio GD op-amps? This stuff still makes almost no sense to me, but I'm giving this stock OPA a good listen before I swap in my OPA2134.


 
  
 I have tried the three Audio-gd opamps and sold them off except for Sun for its uniquely fun sound.  But I very much prefer good ol' high-tech audio-specified opamps.
  
 A little tip on the a-gd opamps: those stock MKT polyester caps really need to be replaced.  They barely do justice to the things.  This guy puts Mundorf caps on old Bursons.  This guy sets the example for the a-gd opamps.
This guy probably beats all of us at going too far.  I would instead add regulators before reaching such a point, lol.
  
  
 On an unrelated note, anyone tried this one?  Or this one?


----------



## zilch0md

Frankenops!


----------



## richard612

Didn't see any discussion on this topic: I'm driving the Fidelio X1 "barefoot" (no amp) with a DSX.  I have the opposite problem that most people have.  Instead of lacking the voltage swing to drive 600 ohm cans, I'm lacking the current to properly drive these 32 ohm cans.  Don't tell me how "easy" it is to drive a 32 ohm load; from a design perspective the 600 ohm load is MUCH easier to deal with, especially in light of the output impedance around 10 ohms (it's hardly a factor when the load presents 600 ohms; it MATTERS when the load is 32).
  
 Some of the opamps getting kicked around on this thread are rated for >50mA continuous.  Might one of these help?  The NJM4556 is the most interesting.


----------



## DingoSmuggler

richard612 said:


> Didn't see any discussion on this topic: I'm driving the Fidelio X1 "barefoot" (no amp) with a DSX.  I have the opposite problem that most people have.  Instead of lacking the voltage swing to drive 600 ohm cans, I'm lacking the current to properly drive these 32 ohm cans.  Don't tell me how "easy" it is to drive a 32 ohm load; from a design perspective the 600 ohm load is MUCH easier to deal with, especially in light of the output impedance around 10 ohms (it's hardly a factor when the load presents 600 ohms; it MATTERS when the load is 32).
> 
> Some of the opamps getting kicked around on this thread are rated for >50mA continuous.  Might one of these help?  The NJM4556 is the most interesting.


 
 Yeah the NJM4556 would've been my first suggestion for performance into low-Z loads.


----------



## richard612

dingosmuggler said:


> Yeah the NJM4556 would've been my first suggestion for performance into low-Z loads.


 
 Order a 4556 from Digi-key.  Installed.  Pretty sure it's driving my low-Z cans more cleanly at high levels.  I still recommend an amp (or a card with more cajones at the output), but this is better.


----------



## LiekZomg

//ignore please~~


----------



## Mach3

Need some clarification on the following opamps
  
 Difference
 OPA827SM
 OPA627SM
 OPA128SM
  
 Is the OPA128 superior to the top two and anyone know where I can purchase them for a reasonable price. Need 4 to on 2 adapter to fill out the headphone buffer on my Asus E1.


----------



## Mad Max

OPA827 frickin' rules!  Very, very high fidelity.
 I don't like OPA627, but it has its hefty fan base.


----------



## DingoSmuggler

mach3 said:


> Need some clarification on the following opamps
> 
> Difference
> OPA827SM
> ...


 
 I would steer clear of the OPA128, amazing dc specs, average ac specs (of those they even bother to list on the datasheet). Its designed for instrumentation, not audio.
  
 An opamp that has me a bit curious these days for buffer type applications is the MUSES8920, good current output, jfet input, and wide open-loop bandwidth. I have an application that requires some jfet buffers with good current, so might end up getting some of these, or might just build it with discrete components.


----------



## Mach3

mad max said:


> OPA827 frickin' rules!  Very, very high fidelity.
> I don't like OPA627, but it has its hefty fan base.


 
 I heard the OPA827 have similar characteristic as the OPA627 no?
  


dingosmuggler said:


> I would steer clear of the OPA128, amazing dc specs, average ac specs (of those they even bother to list on the datasheet). Its designed for instrumentation, not audio.
> 
> An opamp that has me a bit curious these days for buffer type applications is the MUSES8920, good current output, jfet input, and wide open-loop bandwidth. I have an application that requires some jfet buffers with good current, so might end up getting some of these, or might just build it with discrete components.


 
 Very interesting MUSES8920 are very affordable. Much more than the MUSES01 and MUSES02. Will give it a try base on your suggestion. Thanks.


----------



## Mad Max

mach3 said:


> I heard the OPA827 have similar characteristic as the OPA627 no?
> ...


 
  
 No, they have nothing in common.


----------



## Mach3

mad max said:


> I have tried the three Audio-gd opamps and sold them off except for Sun for its uniquely fun sound.  But I very much prefer good ol' high-tech audio-specified opamps.
> 
> A little tip on the a-gd opamps: those stock MKT polyester caps really need to be replaced.  They barely do justice to the things.  This guy puts Mundorf caps on old Bursons.  This guy sets the example for the a-gd opamps.
> This guy probably beats all of us at going too far.  I would instead add regulators before reaching such a point, lol.
> ...


 
 Omg the last two links have awesome specs, but their prices scares me.


----------



## SpudHarris

Anyone have experience of LME49600 buffers?


----------



## P701

spudharris said:


> Anyone have experience of LME49600 buffers?



 

I'm using those in my headphone amp. What can I say.... does its job and cant hear any coloring of sound what so ever.


----------



## SpudHarris

Cheers.

Tried most others so ordered 4 on dip adapters.....


----------



## zilch0md

And I'm still trying to trade my Muses 02s for 01s.


----------



## doors666

i am trying to make a cmoy like thingie using ne5532 (thats all i have at hand in duals at present, might replace later). power right now is from 7815/7915. I am using r2=27k, r3=33k, r4=150k. Load is a 330R resistor. Ckt is here. Cap is presently 0.1uf for testing, will increase it later. ckt is on breadboard.I am giving a single channel an output from a sig gen. Similar ckt worked fine in ltspice.
  
 Output pic is attached. Blue is input and red is output. Could someone please tell me why is it coming like this and how do i fix this.


----------



## thecourier

Guys, anyone have experience with the Burson supreme opamps? (link)
  
 Still deciding if i mod my existing music hall dac or sell it and upgrade. My preference always been with discrete designs.


----------



## zilch0md

http://www.head-fi.org/newsearch/?search=burson+supreme&resultSortingPreference=recency&byuser=&output=posts&sdate=0&newer=1&type=all&containingthread%5B0%5D=432749&advanced=1


----------



## Strangelove424

I ordered some lme49990s a few days ago. I'm excited about them arriving soon, and the specifications are impressive, except for the fact that nowhere in the datasheets for the 49990 (in comparison to the 49860s) were there any crosstalk specs. I found that little odd, unless I don't have the full datasheets. Links I used are below.
  
 http://www.ti.com/lit/ds/symlink/lme49860.pdf
  
 http://www.ti.com/lit/ds/symlink/lme49990.pdf


----------



## DingoSmuggler

strangelove424 said:


> I ordered some lme49990s a few days ago. I'm excited about them arriving soon, and the specifications are impressive, except for the fact that nowhere in the datasheets for the 49990 (in comparison to the 49860s) were there any crosstalk specs. I found that little odd, unless I don't have the full datasheets. Links I used are below.
> 
> http://www.ti.com/lit/ds/symlink/lme49860.pdf
> 
> http://www.ti.com/lit/ds/symlink/lme49990.pdf


 
 One is a dual opamp, the other single...


----------



## Strangelove424

Ha, thanks, did not catch that. Does this mean an adapter is required for direct replacement of 49860 in a dual/buffer layout such as the Essence STX?


----------



## thecourier

zilch0md said:


> http://www.head-fi.org/newsearch/?search=burson+supreme&resultSortingPreference=recency&byuser=&output=posts&sdate=0&newer=1&type=all&containingthread%5B0%5D=432749&advanced=1


 
  
 Well, i'm already familiar with the search function and there's nothing useful. Thanks @zilch0md
  
 Anyone else?


----------



## zilch0md

Right - I was saying it has been recently queried and no one contributed anything.  I could have been nicer about it.  My apologies.


----------



## wigglepuff

what's the difference between muses 01 and 02? I dont really understand individual opamps, but do these 2 differ on how they sound when put into use in an amp?


----------



## P701

wigglepuff said:


> what's the difference between muses 01 and 02? I dont really understand individual opamps, but do these 2 differ on how they sound when put into use in an amp?



 

Specs. The other is J-FET and the other Bipolar.
Yes, sure they can differ in sound if you have enough imagination.


----------



## wigglepuff

p701 said:


> wigglepuff said:
> 
> 
> > what's the difference between muses 01 and 02? I dont really understand individual opamps, but do these 2 differ on how they sound when put into use in an amp?
> ...


 

 lol ok so they sound identical, just that thier hardware implementation differs.


----------



## gibosi

wigglepuff said:


> lol ok so they sound identical, just that thier hardware implementation differs.


 
  
 As I have plenty of imagination. I do not find them to sound identical. lol The J-FET MUSES01 is a bit brighter and tighter in the top end whereas the Bipolar MUSES02 is a bit warmer.
  
 Per zilch0md,  "The MUSES02's biggest advantage over the MUSES01, at least in terms of specifications, is that the ~02 offers 50mA per channel instead of 25mA from the ~01, and the ~02 can get by with a supply voltage of 3.5V vs. 9V."
  
 http://www.head-fi.org/t/432749/the-opamp-thread/4515#post_9973309


----------



## zilch0md

gibosi said:


> As I have plenty of imagination. I do not find them to sound identical.
> 
> [snip]


 
  
 Haha!  Good one!


----------



## wigglepuff

gibosi said:


> As I have plenty of imagination. I do not find them to sound identical. lol The J-FET MUSES01 is a bit brighter and tighter in the top end whereas the Bipolar MUSES02 is a bit warmer.
> 
> Per zilch0md,  "The MUSES02's biggest advantage over the MUSES01, at least in terms of specifications, is that the ~02 offers 50mA per channel instead of 25mA from the ~01, and the ~02 can get by with a supply voltage of 3.5V vs. 9V."
> 
> http://www.head-fi.org/t/432749/the-opamp-thread/4515#post_9973309


 

 lol ok is the bright 01 and the warm 02.


----------



## zilch0md

wigglepuff said:


> lol ok is the bright 01 and the warm 02.


 
  
  
 That's the consensus of most people who have heard them both - but maybe it's more like "the neutral 01 and the warm 02..."


----------



## gibosi

zilch0md said:


> That's the consensus of most people who have heard them both - but maybe it's more like "the neutral 01 and the warm 02..."


 
  
 Yeah, I think this is probably a more accurate way to describe these. In my simplistic mind the 01 is a good chip in a DAC, where neutrality and detail are paramount, and the 02 is a good chip in the output stage due to its power, impact and propulsive rhythm 
  
 Audiofanboy did a nice comparison:
  
 http://www.head-fi.org/t/432749/the-opamp-thread/4590#post_10164689


----------



## wigglepuff

ok thanks, so hopefully the fiio e12a sounds good with the 02 in it (still the warm sound sig by fiio i guess). was planning to get the asus using the 01s but it isn't available in my area.


----------



## EdibleStereos

Been out of the hobby for a while. Was a big fan of the 8610's in my PPA V2 and the 8620's on my sound card.

 Any new opamps that are comparable in the last few years? Something fast and detailed.


----------



## CJG888

I'm based in Shanghai and am looking for a source for a genuine MUSES02.

Does anyone have any recommendations?

I found this link on E-Bay:

http://www.ebay.co.uk/itm/1PCS-ORIGINAL-MUSES02-High-Quality-Audio-J-FET-Input-Dual-Operational-Amplifier-/161085566222

Does it look genuine?


----------



## DingoSmuggler

cjg888 said:


> I'm based in Shanghai and am looking for a source for a genuine MUSES02.
> 
> Does anyone have any recommendations?
> 
> ...


 
 Look like fakes to me, the logo is all messed up and the ink is too white.
  
 refer this picture of MUSE01 fake is left, genuine right...
http://www.overclockers.com.au/pix/index.php?page=image&id=4tbcb


----------



## CJG888

Thank you.

Do you have any idea where I might be able to find a genuine one?


----------



## gibosi

cjg888 said:


> Do you have any idea where I might be able to find a genuine one?


 
  
 A number of us have purchased from this vendor:
  
 http://www.ebay.com/itm/400418607953
  
 I have both the MUSES01 and the MUSES02 from this vendor and there is no doubt in my mind that they are genuine.


----------



## zilch0md

And you got a good price. I paid $75 each at Mouser.com.


----------



## ClieOS

Better just order from the Japanese official distributor via a proxy buying service that takes guesswork out.


----------



## SpudHarris

clieos said:


> Better just order from the Japanese official distributor via a proxy buying service that takes guesswork out.


 
  
 + 1


----------



## Mach3

dingosmuggler said:


> Look like fakes to me, the logo is all messed up and the ink is too white.
> 
> refer this picture of MUSE01 fake is left, genuine right...
> http://www.overclockers.com.au/pix/index.php?page=image&id=4tbcb


 
 Those photo where taken by me about a month ago when I received 12x MUSES01 I purchased from Japanese online store. Cost was $46AUD each including shipping.
 Here are some better photo and the unique package they came in.


----------



## Marrakas

Hi, just a quick question. I have a motherboard with a replacable op-amp (OPA2134 originally inserted), and I've been trying different ones just for fun. But for some reason they all end up giving me really murky sound and on one ear only. Am I doing something wrong, or have I just gotten really unlucky with a batch of bad amps off ebay? I always end up putting the original back in, and it works pretty well.


----------



## SpudHarris

Out of curiosity what have you been using as replacements?


----------



## Marrakas

I tried an AD843JN and a OPA627AP cause I heard those were supposedly very good allrounders.


----------



## SpudHarris

The 2134 is a dual and the others are single OpAmps you would need 2 of each on an adapter to replace the 2134



That's why you only hear it in one channel.

Hope that helps.


----------



## Marrakas

That makes sense. Thanks, I knew something was really wrong here, and I suspected it was me being a total noob on this kinda stuff.
  
 So if I buy one of those adapters it should work even on my motherboard?


----------



## SpudHarris

Indeed. 

You need a single to dual DIP adapter. E-bay is your best bet.

By the way the two OpAmps you chose are great. The 627 is an all time favourite within the audiophile community and the 843 is a very aggressive (fast powerful) sounding OpAmp. As long as you bought them from reputable sellers, I am sure you will enjoy both.

Regards - Nigel


----------



## CJG888

mach3 said:


> dingosmuggler said:
> 
> 
> > Look like fakes to me, the logo is all messed up and the ink is too white.
> ...


----------



## Mach3

cjg888 said:


> Those are the genuine ones, then?


 
 Yep
  
_There's only three authorized resellers I know that sells genuine MUSES opamps besides mouser and digikey (Who are both too expensive). I emailed NJR them self to confirm._
_http://akizukidenshi.com/_
_http://eleshop.jp/_
_http://www.chip1stop.com/_

_I ordered my 12 MUSES01 from __http://akizukidenshi.com/__. The site doesn't support english, fully japanese only._


----------



## dhc0329

I am currently using OPA211ID*2 converted to dual op amp [DIP-8 package, dual channel op amp] so it is actually 6 x OPA211ID total. I think it sounds warm and deep.


----------



## razzz42

pluto2 said:


> Or any better suggestion other than LT1352 for filters?
> 
> BTW, any opamp has interesting quality for mid and bass?


 
 Old TL082CN handles bass well (it's dual channel). 8066AR handles bass even better (single channel, needs an adapter, eBay has them already mounted). LT1028ACN8 for the output (filter?) socket will enhance any opamp before it (requires an adapter and a lot of room since it is side-by-side usually).


----------



## Pluto2

razzz42 said:


> Old TL082CN handles bass well (it's dual channel). 8066AR handles bass even better (single channel, needs an adapter, eBay has them already mounted). LT1028ACN8 for the output (filter?) socket will enhance any opamp before it (requires an adapter and a lot of room since it is side-by-side usually).




Thanks for replying to my old questions.
Have been using ada4627 and opa827 in the active crossover...havent done any rolling since then.....
Not sure I could hear much difference. There was a difference when I swapped the opa2124 with lm4562 though..


----------



## razzz42

A lot of times you will get clarity and not know it. Most of time you get a veil where the opamp puts its own color on the sound and if there was clarity, it is now hidden in the veil/coloring.
  
 The old 5532D is really clear, the standard for years.
  
 LME49860NA is fairly clear while it enhances the vocal range.
  
 LME 49990 is a very good all around sound opamp usually found in consumer DVD players where they bothered to design and build around the opamp.


----------



## michaelvv

spudharris said:


> Indeed.
> 
> You need a single to dual DIP adapter. E-bay is your best bet.
> 
> ...


 
  
 Hi SpudHarris...
  
 Saw your excellent collections of op Amps on a previous post...
  
 I just tried the LT1028ACN8, which I'm complete in love with 
  
 Have you tried this, and If so, do you have some suggestion for
 improvements if you just like LT1028ACN8...
  
 /Thanks Michael.


----------



## zilch0md

razzz42 said:


> [snip]
> 
> *The old 5532D is really clear, the standard for years.*
> 
> [snip]


 
  
 The 5532D must be a lot different from the NE5532AP I tried in my iBasso PB2.
  
 http://www.head-fi.org/t/528149/ibasso-pb-2-pelican-fully-balanced-portable-db-2-dac-hiflight-recommended-op-amps-page-16/1110#post_10649428
  
 Mike


----------



## Mad Max

49860 is uber hi-fi.  It is more than "fairly clear".


----------



## dwayniac

I am trying OpAmp rolling for first time. I put a 2134 in a Audinst AMP-HP and I give it slight edge over the stock OpAmp.


----------



## zilch0md

dwayniac said:


> I am trying OpAmp rolling for first time. I put a 2134 in a Audinst AMP-HP and I give it slight edge over the stock OpAmp.


 
  
 You're hooked now!


----------



## leeperry

dwayniac said:


> I am trying OpAmp rolling for first time. I put a 2134 in a Audinst AMP-HP and I give it slight edge over the stock OpAmp.


 
  

  
  You are doomed


----------



## Mad Max

dwayniac said:


> I am trying OpAmp rolling for first time. I put a 2134 in a Audinst AMP-HP and I give it slight edge over the stock OpAmp.


 
  
 It has begun!


----------



## dwayniac

zilch0md said:


> You're hooked now!







leeperry said:


> You are doomed :evil:







mad max said:


> It has begun!





Nooooooooooooooooooo........!!!!


----------



## zilch0md

^  Haha!


----------



## razzz42

zilch0md said:


> The 5532D must be a lot different from the NE5532AP I tried in my iBasso PB2.
> 
> http://www.head-fi.org/t/528149/ibasso-pb-2-pelican-fully-balanced-portable-db-2-dac-hiflight-recommended-op-amps-page-16/1110#post_10649428
> 
> Mike


 
 5532D is old school, at best for comparison only.
  
 LME 49990 or if you can't afford those single channel needing adapters then use LME49860NA which is dual channel. If you did nothing else, you would survive just fine with the LMEs. A plus is being able to buffer the LME with a couple of LT1028ACN8 and that would be a benchmark to try and beat.
  
 This french girl's voice seems to be captured by a great pickup opamp (and mike). Her previous rough videos all do a fine job picking up her voice. She is no Frank Sinatra where I swear the guy could create a note when inhaling because you never hear him breathing but none the less this girl processes a clear voice. http://youtu.be/UQUXB57BWPM


----------



## Mad Max

dwayniac said:


> Nooooooooooooooooooo........!!!!


 
  
 Wait until you start doing more:


----------



## dwayniac

Yeah I will do more,with two more on the way,but I want to keep it limited to the one amp I can roll opamps with.


----------



## dwayniac

Within my current combo of headphone, amp & dac:

LM4556>OPA2134>MUSES02


----------



## FritzS

dwayniac said:


> Within my current combo of headphone, amp & dac:
> 
> LM4556>OPA2134>MUSES02


 

 You mean better>   / or   >better


----------



## dwayniac

fritzs said:


> You mean better>   / or   >better




Like.....better>


----------



## palermo

Bump this thread.. Have you guys ever try LT1366 or LT1368 ? I will place in FiiO X1. I found my X1 sounds not right to me, I think it too thick and forward. So I did a little mod in analog section. There are two opamp after DAC, OPA2322 and ISL28291. I don't exactly know what that purpose, since the DAC PCM5142 has internal buffer I/V itself. The output DAC should be already 2V. I think it kind of buffer headamp without voltage gain. OK its too technically for me. But my main concern is the sound. 
 Just see into the specs and from this site http://tieba.baidu.com/p/3323609195?pn=1 , both opamp are RRIO, and operates 2.5V. So finally I change OPA2322 > LT1361 and ISL28291 > LME49721. LT1361 run nicely though that is not RRIO. I want to try LT1366 and LT1368, but I didn't find any comment about these opamp.


----------



## Mad Max

I might have tried 1368 in the past and thought it sucked.  I haven't liked any LT chips yet, it is best to stick to Analog and TI chips for audio, I think.  OPA2365 is a real nice chip, I'm told, and it is rail-to-rail like 2322 with the same operating voltage range.  I haven't tried it and don't have any equipment that I can use it in.


----------



## palermo

Thank you, I will try opa1612 then.


----------



## dwayniac

Any recommendations for opamps with very good,punchy bass?


----------



## gibosi

dwayniac said:


> Any recommendations for opamps with very good,punchy bass?


 
  
 In my limited experience, the MUSES02 might be a good choice. I am using one of these in the output stage of a hybrid amp (Little Dot 1+) and am very pleased with it.


----------



## razzz42

TL-082 Although general purpose, it is pretty good at producing bass.

AD8066AR needs an adapter but handles bass really well.


----------



## Apocalypsee

I bought a couple of LME49710HA for my Titanium HD, I already have LME49720HA for I/V but because of my previous impression the HA is far better than NA so I bought the HA version of 49710 and I'm not disappointed. Indeed it sounds better, no longer sterile on female vocal. Funny that the two different chips on different packaging makes things sounds different


----------



## echineko

Hi guys,
  
 I've tried the MUSES01/02 opamps for my Asus Essence STX II soundcard, thinking of getting the FiiO 12DIY to mess about with as well. Other than the MUSES, people seem to have high regard for the LME49990s, any other opamps worth trying out? There's 2 buffer slots and 1 output slot for the E12DIY that can be configured, if I recall correctly


----------



## Mad Max

apocalypsee said:


> I bought a couple of LME49710HA for my Titanium HD, I already have LME49720HA for I/V but because of my previous impression the HA is far better than NA so I bought the HA version of 49710 and I'm not disappointed. Indeed it sounds better, no longer sterile on female vocal. Funny that the two different chips on different packaging makes things sounds different


 

 You can maximize their sound quality, but possibly stop hearing a difference between the two grades, if you gave them better power decoupling capacitors like HDAM users put Mundorf or old Soviet caps on their "discrete" opamps.  You can see all sorts of relevant photos in a google search or *Recent Images In This Thread* up in the corner of any page of this thread if you are not on a mobile device.  I swear by Vishay MKP1837 film capacitors or WIMA MKP4 if there is not enough room for the bulky Vishays.  Some opamps just need a 0.1uF 50V C0G ceramic capacitor across their power pins for best sound in a given circuit.


----------



## palermo

recently mod my ALO the Island. It has slight on warm side, but already great soundstage, particularly the balanced output. the clarity i so so.
 the DAC is CS4398 following by NE5532 as LPF and gain stage, while balance driver use SSM2142. 
 I tried LT1361 as LPF and I got neat sound, but not as clean as I want. I am going to swap it to lme49720ma, AD8599 on gainstage, or something else.
 Anyone can advice me for opamp replacement. I need fatty bass and goes lower as possible without losing clarity.


----------



## fadhlysb

guys  i wanna know about LME49720NA... is it that great?


----------



## Apocalypsee

fadhlysb said:


> guys  i wanna know about LME49720NA... is it that great?


 

 The LME49720NA is quite good but the HA version is better


----------



## Mad Max

fadhlysb said:


> guys  i wanna know about LME49720NA... is it that great?


 
  
 In the right circuit yes.  And in the wrong one it will overheat enough to cook a steak.
 It gets even better with a film cap across its power pins, see this thread's gallery.


----------



## imran27

For a DIY AMP+DAC, which opamp and DAC chip would you recommend? I'm going for DIY just for fun and learning and also it'll make it very much customizable and modular as per my thought design


----------



## unknownguardian

any impression of opa627bm and opa627sm?


----------



## imran27

unknownguardian said:


> any impression of opa627bm and opa627sm?


 
 Looking at the specs and customer reviews of the OPA627, it does seem to be very very good as an audio op-amp. Although OPA637 has much lower THD+N and might be much more clearer and detailed (pure speculation based on high slew rate, 135 V/uS). The noise >15nV/rHz at 10 HZ and lower that this opamp has might not bother much.
  
 I was thinking that is it worth building a complete AMP+DAC combo as DIY or just AMP for now (using Dragonfly as DAC)!


----------



## unknownguardian

imran27 said:


> Looking at the specs and customer reviews of the OPA627, it does seem to be very very good as an audio op-amp. Although OPA637 has much lower THD+N and might be much more clearer and detailed (pure speculation based on high slew rate, 135 V/uS). The noise >15nV/rHz at 10 HZ and lower that this opamp has might not bother much.
> 
> I was thinking that is it worth building a complete AMP+DAC combo as DIY or just AMP for now (using Dragonfly as DAC)!


 
 because i read online that OPA627BM might be too harsh sounding for some. some commented that the bass might hit too hard and be boomy. so was wondering will there be anyone who had previously used/currently using it share their opinion on it.


----------



## imran27

unknownguardian said:


> because i read online that OPA627BM might be too harsh sounding for some. some commented that the bass might hit too hard and be boomy. so was wondering will there be anyone who had previously used/currently using it share their opinion on it.


 
 Hmmmm, true.
  
 That makes OPA1612 a very viable alternative


----------



## FritzS

imran27 said:


> Looking at the specs and customer reviews of the OPA627, it does seem to be very very good as an audio op-amp. Although OPA637 has much lower THD+N and might be much more clearer and detailed (pure speculation based on high slew rate, 135 V/uS). The noise >15nV/rHz at 10 HZ and lower that this opamp has might not bother much.
> 
> I was thinking that is it worth building a complete AMP+DAC combo as DIY or just AMP for now (using Dragonfly as DAC)!


 
  
  


unknownguardian said:


> because i read online that OPA627BM might be too harsh sounding for some. some commented that the bass might hit too hard and be boomy. so was wondering will there be anyone who had previously used/currently using it share their opinion on it.


 

 I like the OPA627 in my headphone amp WNA MKII 
	

	
	
		
		

		
			




  
 I had test a lot of OPA's before too!
 Original LM6171, then AD843, LME49710, AD847, LT1056, OPA602AP,  LT1022, TLE2071, OPA134 and now *OPA627*
  
 http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit/720
 ....
 http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit/750


----------



## imran27

fritzs said:


> I like the OPA627 in my headphone amp WNA MKII
> 
> 
> 
> ... 
 So what are your opinions on the sound of these opamps you tested?
  
 As of now I've shortlisted following for my DIY AMP+DAC:
 - PCM1794A (24-bit 192khZ & 132dB SNR)
 - PCM2704C
 - OPA827
  
 I'd like to evaluate OPA627, OPA637 & OPA1612 as well, but they are not very cheap hence I choose OPA827 & a pair of one of the latter three (probably I'll choose OPA637 or OPA627)


----------



## P701

Heh, that is good read.
Switching to opamp that does not function the best way in certain circuit can cause that different "sound", noise, distortion.
There might be slight audible differences between JFET and bipolar opamps tho.
Maybe some features such as stereo crosstalk might be audible.
The other features such as THD etc will most likely already be limited by your other hadware (and human hearing) for any audible differences.

I myself have a small smile in my face whenever I read expressions from people about the OP Amp swapping with "wow! I never heard this piano was here!", "this opamp has good bass and this other doesnt", "now i can hear all the small details", "this op amp sounds too harsh and this other sounds warm".


----------



## FritzS

p701 said:


> There might be slight audible differences between JFET and bipolar opamps tho.
> Maybe some features such as stereo crosstalk might be audible.


 
  
 I like JFET input OPAs more than bipolar input OPAs.


----------



## Mad Max

p701 said:


> ...
> Maybe some features such as stereo crosstalk might be audible.
> ...


 
  
 Not in modern opamps.


----------



## P701

LMAO... admins are censoring and deleting posts, which imran27 posted and I quoted to.
It contained alot of info and measurements from op amps, but seems it is not good for "hifi" forum.


----------



## SpudHarris

Is anyone gonna feed it? :rolleyes:


----------



## zilch0md

I missed out, but there must have been a link to a banned member page. They wouldn't yank posts just for technical content.


----------



## imran27

Maybe the blog is being run by a Head-Fi banned member. Although the technical content and the proof of substance was par excellence.
  
 That made me understand one thing, that using those opamps that are designed for non audio purposes such as precision measurements, instrumentation, biomedics etc. will not work as a good "drop-in" replacement of an audio opamp or a circuit designed for audio opamps. The circuit has to be optimized for the opamp we are using.
  
 Also, if we consider the DAC output of 192kHz which has a cycle timing of ~5.2uS will have 1.3uS half-pulse width which is the duration in which opamp must be able to swing it's output from low to high voltage. This helps us understand that a "very high" slew rate is not required even for current 192kHz audio signals. We can use audio opamps with slew rate > 10V/uS easily. It is their bandwidth and other circuit components that decide the whole circuit behaviour not just the opamp alone (though opamp is an important part).
  
 I think I will skip OPA827 and go for other audio focused opamps like LME49722 or the likes of it.


----------



## echineko

Guys,

I've got me an Ibasso d42 inbound, and was thinking of going for dual LME49990 for the buffer stage, and a MUSES02 for the opamp, any reason this would be a bad idea? Any better components to try? Thanks!


----------



## Mad Max

Muses02 in voltage gain?  Try LME49990 there instead and BUF634 in the buffer, then rock on.


----------



## zilch0md

Yeah, I love my LME49990 singles in the I/V stage, but didn't like them as buffers.


----------



## echineko

mad max said:


> Muses02 in voltage gain?  Try LME49990 there instead and BUF634 in the buffer, then rock on.




Hmm, thanks, will give that a try!


----------



## SpudHarris

Been loving the LME49600 as buffers in my P4 but the modules I bought would not fit my Fi-quest.



So with the advice of my guru 'HiFlight' I made up some within a DIP foot print to fit. These are by far the nicest of buffers...


----------



## Mad Max

Thanks pretty clever.


----------



## EniGmA1987

I see a lot of people mentioning putting a capacitor soldered between the two power pins on an op amp. Is this really the best/right way to do it? Or should the capacitor(s) be from V+ pin to ground and V- pin to ground? the datasheets talk about adding bypass capacitors to the power pins, so that means the capacitors should be from the power pin to ground in order to be working correctly right?


----------



## Mad Max

enigma1987 said:


> I see a lot of people mentioning putting a capacitor soldered between the two power pins on an op amp. Is this really the best/right way to do it? Or should the capacitor(s) be from V+ pin to ground and V- pin to ground? the datasheets talk about adding bypass capacitors to the power pins, so that means the capacitors should be from the power pin to ground in order to be working correctly right?


 
  
 If the device that the opamps are in in question uses virtual ground, then it is best to have the cap across the power pins.  If you have real ground, then one cap per pin and then both connecting to ground is a great idea.  If there's no nearby hardpoint(s) to solder the cap legs to ground, then you can solder the legs to each other then add a thick wire going to some ground point where you can reach.


----------



## EniGmA1987

mad max said:


> If the device that the opamps are in in question uses virtual ground, then it is best to have the cap across the power pins.  If you have real ground, then one cap per pin and then both connecting to ground is a great idea.  If there's no nearby hardpoint(s) to solder the cap legs to ground, then you can solder the legs to each other then add a thick wire going to some ground point where you can reach.


 
  
 Thanks for the info. The stock op amps that come in my DAC + headphone amp do not have an actual ground connection, but some of the official upgrade op amps do have an actual ground wire and a place to connect them to earth ground. So I assume this means I should have a real ground I can use. The ground is really close to the op amp socket, so I was planning on crimping a ring terminal onto the end of one of the legs of each capacitor to connect to the ground screw and then solder the other leg of each capacitor to the proper power pin on my op amp adapter PCBs.


----------



## Mad Max

enigma1987 said:


> Thanks for the info. The stock op amps that come in my DAC + headphone amp do not have an actual ground connection, but some of the official upgrade op amps do have an actual ground wire and a place to connect them to earth ground. So I assume this means I should have a real ground I can use. The ground is really close to the op amp socket, so I was planning on crimping a ring terminal onto the end of one of the legs of each capacitor to connect to the ground screw and then solder the other leg of each capacitor to the proper power pin on my op amp adapter PCBs.


 
  
 I do not recommend crimping terminal rings directly to cap leads, use a short length of wire instead.  I use 24awg or 22awg Mogami wire for ground leads, whichever I happen to have on hand.  These stranded wires will take more punishment than solid capacitor leads, unless you intend to swap in a different opamp only once and never again.
  
 If the upgrade opamps in question are audio-gd's HDAMs, some people like those best with ungrounded decoupling and a 1uF Soviet K42-Y2 film capacitor across the power pins in place of the original EVOX MKT capacitors.  I got to try that out earlier this year, and Sun is even more fun and higher fidelity that way, but I sold off Earth and Moon long ago and can't try those with upgrade caps.  The little grey EVOX caps they normally have don't bring out the best sound in Sun at all, I have no doubts that the same applies to Earth and Moon.
  
 As nice as audio-gd opamps are, though, they don't beat TI and ADI chips in sound like OPA827, ADA4627-1B, LME49990, or OPA1612, but they are indeed a nice way to flavor things up a bit.  I recommend Vishay MKP1837 decoupling caps if you go with any of those chips I mentioned, best film caps.  Or WIMA MKP4 if you can't source those.
 Edit: MKP1839 is fine, too, just as good as 1837.


----------



## EniGmA1987

mad max said:


> I do not recommend crimping terminal rings directly to cap leads, use a short length of wire instead.  I use 24awg or 22awg Mogami wire for ground leads, whichever I happen to have on hand.  These stranded wires will take more punishment than solid capacitor leads, unless you intend to swap in a different opamp only once and never again.
> 
> If the upgrade opamps in question are audio-gd's HDAMs, some people like those best with ungrounded decoupling and a 1uF Soviet K42-Y2 film capacitor across the power pins in place of the original EVOX MKT capacitors.  I got to try that out earlier this year, and Sun is even more fun and higher fidelity that way, but I sold off Earth and Moon long ago and can't try those with upgrade caps.  The little grey EVOX caps they normally have don't bring out the best sound in Sun at all, I have no doubts that the same applies to Earth and Moon.
> 
> ...



 


Good thought on the solid capacitor leads. I don't really plan to change out the op amps much, once I decide which one I like it will probably stay for years, but who knows how many swaps back and forth will go on over a couple weekends while I decide. lol

I have an OPA Earth and Moon, currently using the earth because I wanted a bit more bass. Before that I had used some AD797B's (much better than regular AD797A) that I really liked and they do sound better than the Earth, but don't have quite as much low end. I never even thought much about modding them too but Ill definitely be doing that now too. I had never really heard of the capacitors on the op amps before recently, but I decided to put them on my AD797B's and give them a go again, and I see after looking at the datasheet that Analog Devices actually recommends multiple bypassing using a 1-4.7uF tantalum and a parallel 0.1uf ceramic capacitor on each power leg to ground. I am going to use a 2.2uF Mundorf aluminum+oil film cap as well as a 0.1uf Mundorf silver|gold +oil film cap. Those would be each power pin to ground. Or my other thought is, upgrade both cap's to the silver|gold + oil's and only use two capacitors just between the two power pins and don't bother with the ground wire. Any thoughts on which way might be better?

I also bought some LME49990's after reading about their use from people in this thread, and I have some K42-Y2's coming as well with them. So Looks like I'll be auditioning between 3 op amps. Do you think it would be better to use the MKP1837's instead of the K42-Y2's specifically on the LME49990?


----------



## imran27

For my DIY DAC+AMP I've been reading design and some technical papers a lot (I'm Electronics Engineer by profession)
  
 What is the technical/electronic counterpart of soundstage? Is it related to "Phase Response" of the AMP circuit? Or is it related to relative phase response of L & R or crosstalk between them?
  
 One thing I truly admit and understand is that op-amps DO NOT have any particular sound! It is the circuit around them which is made for a different op-amp makes it sound "different". Just assuming that soundstage is related to phase response then replacing some op-amp with different ones will very likely change it's PR and hence soundstage.
  
 Instead of changing op-amps we could try changing the FR & PR of the circuit to see how that affects.
  
 I will likely build a test amp in order to test these things soon.
  
 If someone would like to comment or extend upon this then please do, you're most welcome
  
 EDIT: And hey @EniGmA1987 nice to see you here


----------



## Mad Max

Well, sticking an opamp in a circuit not designed for it is one way to get some thing different, already mentioned in this thread many times by now.  Distortion, feedback loops now having to work for the wrong opamp resulting in mild FR changes, and so forth.  Sticking instrumentation opamps in an audio circuit, this hobby is riot!  And a damned waste of time, but we still do it anyway.  It is fun despite being silly.  I hardly roll lately, though.
  
 Phase has something to do with it, I've read.  The rest is psychoacoustics stuff no one gets, hahaha!
 I find that soundstaging usually sounds better with higher-output current opamps, regardless of whether one is using low-impedance or high-impedance headphones.  Other than that, I've read here that output current is more important to low-impedance cans, higher voltage swing for high-impedance cans (preferably the +/-15V swing of desktop amplifiers).
  
 PR = "pulse reponse" I assume?  From what I've read, which hasn't been very much, pulse response is adjusted with inductance.  More inductor-capacitor-inductor-capacitor layout going on in the PSU to "slow down" the power, giving equipment more of a "soft-start" trait, good for the lifespan of equipment.  But adding inductors for this and that anywhere seems to start adding coloration to the sound for the most part.  Caps in the signal path tend to have a similar effect of adding coloration, though adding bandwidth-limiting capacitors to opamp feedback resistors seems to do no harm - quite the opposite in fact, they sound even better.


----------



## imran27

mad max said:


> Well, sticking an opamp in a circuit not designed for it is one way to get some thing different, already mentioned in this thread many times by now.  Distortion, feedback loops now having to work for the wrong opamp resulting in mild FR changes, and so forth.  Sticking instrumentation opamps in an audio circuit, this hobby is riot!  And a damned waste of time, but we still do it anyway.  It is fun despite being silly.  I hardly roll lately, though.
> 
> Phase has something to do with it, I've read.  The rest is psychoacoustics stuff no one gets, hahaha!
> I find that soundstaging usually sounds better with higher-output current opamps, regardless of whether one is using low-impedance or high-impedance headphones.  Other than that, I've read here that output current is more important to low-impedance cans, higher voltage swing for high-impedance cans (preferably the +/-15V swing of desktop amplifiers).
> ...


 
 PR meant Phase Response. Soundstaging definitely needs to have a trait in the circuit that changes with different op-amps. I highly suspect it's the phase response of the amp section, but not sure until I test it once and for all. Any psychoacoustic effect is a direct result of some particular change in output of the amp. Two amps having exactly similar phase and frequency response (I tend to trust Step Response more) will likely sound the same.
  
 One more way of making a good amp could be adjust it's step response to have a very low rise time and overshoot but must be stable. This will ensure that amp is perfectly stable yet it can follow the input and recreate it at the output very well.
  
 The questions regarding power supply noise and by-passing have been somewhat answered and covered in whatever @EniGmA1987 asked.


----------



## Mad Max

enigma1987 said:


> Good thought on the solid capacitor leads. I don't really plan to change out the op amps much, once I decide which one I like it will probably stay for years, but who knows how many swaps back and forth will go on over a couple weekends while I decide. lol
> 
> I have an OPA Earth and Moon, currently using the earth because I wanted a bit more bass. Before that I had used some AD797B's (much better than regular AD797A) that I really liked and they do sound better than the Earth, but don't have quite as much low end. I never even thought much about modding them too but Ill definitely be doing that now too. I had never really heard of the capacitors on the op amps before recently, but I decided to put them on my AD797B's and give them a go again, and I see after looking at the datasheet that Analog Devices actually recommends multiple bypassing using a 1-4.7uF tantalum and a parallel 0.1uf ceramic capacitor on each power leg to ground. I am going to use a 2.2uF Mundorf aluminum+oil film cap as well as a 0.1uf Mundorf silver|gold +oil film cap. Those would be each power pin to ground. Or my other thought is, upgrade both cap's to the silver|gold + oil's and only use two capacitors just between the two power pins and don't bother with the ground wire. Any thoughts on which way might be better?
> 
> I also bought some LME49990's after reading about their use from people in this thread, and I have some K42-Y2's coming as well with them. So Looks like I'll be auditioning between 3 op amps. Do you think it would be better to use the MKP1837's instead of the K42-Y2's specifically on the LME49990?


 
  
 Tantalums aren't recommended for audio, at least by more experienced audiophiles with electronics knowledge, usually.  I have spare K42s to try on chip opamps but haven't gotten around to trying them out.
  
 Try both just two-cap scheme or all four and see which you like better.  You can find pics of both types being used by different people in this thread as well as the audio-gd FUN and Compass (not the Compass 2) threads.
  
 As far as AD797, I haven't yet tried adding a 50pF film cap across pin 8 and pin 6 on each chip, that's supposed to minimize a 50pF internal output capacitor.  I suppose I would have to go with WIMA FKP2 10% 47pF caps (10% and not the 5% ones, so- they will vary individually between ~43pF to ~51pF), buy a bunch and get a pair that both measure 50pF.
 Edit: and 797's low end should improve with extra bypass caps, it's really one of the best chips around.


----------



## 00940

mad max said:


> Tantalums aren't recommended for audio, at least by more experienced audiophiles with electronics knowledge, usually.


 
  
 I'd rather say that tantalums aren't usually recommended for audio by audiophiles with too little electronics knowledge to implement them properly. They're perfectly fine if you know how to use them. Actually, as long as you don't do anything stupid such as forgetting to derate their voltage ratings and provide for current limiting.


----------



## Mad Max

00940 said:


> I'd rather say that tantalums aren't usually recommended for audio by audiophiles with too little electronics knowledge to implement them properly. They're perfectly fine if you know how to use them. Actually, as long as you don't do anything stupid such as forgetting to derate their voltage ratings and provide for current limiting.


 
  
 I suppose that would include resistors and other stuff?
 Edit: I hope that doesn't require adding a dozen more components, hoho!


----------



## 00940

mad max said:


> I suppose that would include resistors and other stuff?
> Edit: I hope that doesn't require adding a dozen more components, hoho!


 
  
 Not really. It would include considering what capacitors you put in //, their respective esr, capacitance, etc. It could include using tantalum mostly for RC filters and avoid places which could confront the caps to extremely fast charge-discharge.
  
 To back up the tantalum's audiophile credentials, Ray Samuels' products are full of them.


----------



## imran27

Does anyone know if it makes a difference in using an Instrumentation Amplifier after I/V stage instead of a simple Differential Amplifier, soundwise of course since technically IA is always better than the latter?


----------



## 00940

imran27 said:


> Does anyone know if it makes a difference in using an Instrumentation Amplifier after I/V stage instead of a simple Differential Amplifier, soundwise of course since technically IA is always better than the latter?


 
  
 disclaimer: answering from a technical point of view.
  
 There is little point in going for a instrumentation amplifier at this point. The output impedance of the I/V stages are usually well matched and quite low on one hand and, on the other hand, the extra load the differential amplifier puts on the I/V opamps isn't a big deal considering how strongly loaded the I/V opamps already are.
  
 If I was trying to improve the typical opamp based I/V stage, I'd rather put buffers inside the feedback loop of the I/V opamps. jcx (among others) has posted about it in the past (an example here).


----------



## imran27

00940 said:


> disclaimer: answering from a technical point of view.
> 
> There is little point in going for a instrumentation amplifier at this point. The output impedance of the I/V stages are usually well matched and quite low on one hand and, on the other hand, the extra load the differential amplifier puts on the I/V opamps isn't a big deal considering how strongly loaded the I/V opamps already are.
> 
> If I was trying to improve the typical opamp based I/V stage, I'd rather put buffers inside the feedback loop of the I/V opamps. jcx (among others) has posted about it in the past (an example here).


 
 I was actually looking at it in terms of CMRR. IA's typically have a very good CMRR that can decrease the crosstalk between L & R. That in turn will likely improve imaging/positioning by quite a bit since L & R are more isolated now. You might think how is CMRR related to L/R isolation? They will have much better silence (probably coupled with lower noise/higher SNR).
  
 Just trying to think other benefits it might have, or disadvantages otherwise
  
 EDIT: I'm asking and writing in context of designing a completely DIY DAC+AMP for portable use, probably the size of Fiio A17, may be just a little bulkier will also be OK.


----------



## 00940

imran27 said:


> I was actually looking at it in terms of CMRR. IA's typically have a very good CMRR that can decrease the crosstalk between L & R. That in turn will likely improve imaging/positioning by quite a bit since L & R are more isolated now. You might think how is CMRR related to L/R isolation? They will have much better silence (probably coupled with lower noise/higher SNR).
> 
> Just trying to think other benefits it might have, or disadvantages otherwise
> 
> EDIT: I'm asking and writing in context of designing a completely DIY DAC+AMP for portable use, probably the size of Fiio A17, may be just a little bulkier will also be OK.


 
  
 In the context of a I/V, the CMRR is pretty much irrelevant to crosstalk (have a look at the numbers achieved by the pcm1794 datasheet circuit). The only benefit you gain is wrt lower noise as you cancel the noise coming from the DAC analog supply (and some H2 cancellation). In the case of the pcm1794 (to take an example) however, the single-ended performances of the IC are already so good that you don't need much, a few dB are all you need to push you into the crazy low numbers.
  
 And, honnestly, for a portable context, I'd look at voltage out DAC such as AK4399 or WM8741 (if you want top performances, otherwise pcm5102 is really easy to use). You can strongly reduce your power consumption by making the output stage more simple without performance loss.


----------



## imran27

Great suggestion bro.

I'll take that, I guess DragonFly uses WM8741 too.

I was thinking of LME49722 for AMP stage or OPA1612


----------



## 00940

imran27 said:


> Great suggestion bro.
> 
> I'll take that, I guess DragonFly uses WM8741 too.
> 
> I was thinking of LME49722 for AMP stage or OPA1612


 
  
 The Dragonfly uses the ES9023 actually. The wm8740 is used by Amb in his gamma 1.5 for example. 
  
 Those opamps are good audio opamps. The opa1612 swings closer to the rails at first sight, that might be a factor for a portable design.


----------



## SpudHarris

What's the difference (apart from price) between OPA627AP and BP??


----------



## zilch0md

spudharris said:


> What's the difference (apart from price) between OPA627AP and BP??


 
  
 http://www.diyaudio.com/forums/solid-state/9155-opa627ap-bp.html


----------



## FritzS

spudharris said:


> Been loving the LME49600 as buffers in my P4 but the modules I bought would not fit my Fi-quest.
> 
> 
> 
> So with the advice of my guru 'HiFlight' I made up some within a DIP foot print to fit. These are by far the nicest of buffers...


 

 Please look for this old suggestions from Walt Jung!
 http://waltjung.org/PDFs/WTnT_Op_Amp_Audio_1.pdf
 http://waltjung.org/PDFs/WTnT_Op_Amp_Audio_2.pdf
 http://waltjung.org/PDFs/WTnT_Op_Amp_Audio_3.pdf
 http://waltjung.org/PDFs/WTnT_Op_Amp_Audio_4.pdf
 http://waltjung.org/PDFs/WTnT_Practical_Circuits_for_Quiet_Audio_Transmission.pdf
  
 and his new blog  http://waltsblog.waltjung.org/


----------



## Mad Max

Still no word on what opamps are in the Sennheiser amplifiers?


----------



## Magic77

Just replaced the AD825 in my Nighthawk Headphone Amp for the OPA1641. The results are astounding. Completely blows away the AD825 in my opinion. I didn't know I could roll opamps in this amp until I opened the cover. For SOIC chips all you need are the Browndog adapters, such as with the OPA1641. If there are any Nighthawk owners out there, have some fun rolling the opamps. I'm going to try a couple other opamps too.


----------



## Magic77

Can anyone explain the difference between a Bipolar input opamp and a Jfet input opamp? Also, can a bipolar input opamp be used in a circuit that originally used a Jfet opamp? My Nighthawk headphone amp came with an AD825 which is a Jfet input. I first replaced the AD825 with the OPA1641 which seem to work very well. But now I am curious about trying other opamps as well that may have a Bipolar input. Thanks for any help or advice.


----------



## imran27

Can someone please compare between these:

OPA1612
OPA1642
LME49722
LME49990
 I want to know their strengths and weaknesses when used for AMP section. And also which one of the above will be best for I/V and filter stage


----------



## Magic77

I use the OPA1641 in my headphone amp, which is the single version of the OPA1642, 1642 being the dual version. I love the sound of the 1641. I am familiar with the other chips you mentioned also, all being very good for audio applications. I can't give you any specifics about them off the top of my head. Best thing to do is to look at the data sheets for each one on the Texas Instruments website. You should then be able to compare them somewhat. I can only speak for the 1641/1642 as far as sound performance, haven't heard the others you mentioned, but have only seen some of the specs on them. I am probably going to try the 1611 and 49990 sometime soon.


----------



## imran27

magic77 said:


> I use the OPA1641 in my headphone amp, which is the single version of the OPA1642, 1642 being the dual version. I love the sound of the 1641. I am familiar with the other chips you mentioned also, all being very good for audio applications. I can't give you any specifics about them off the top of my head. Best thing to do is to look at the data sheets for each one on the Texas Instruments website. You should then be able to compare them somewhat. I can only speak for the 1641/1642 as far as sound performance, haven't heard the others you mentioned, but have only seen some of the specs on them. I am probably going to try the 1611 and 49990 sometime soon.



I looked at specs already and have been comparing them since last week. They confuse me a lot.

I just wanted to know their relative sonic comparison. Like which opamp is best for what stage, best for i/v or Filter or amp.

I like my sound to be detailed, very will extended in bass & treble and must must have a good soundstage. For sound-stage I guess 1641 will be best. Does it provide a good level detail and extension?


----------



## Magic77

Yes, the specs can be confusing to me too. Are you replacing just a dual chip or a single chip? I know the LME49990 is only a single channel chip. The others come in single and dual versions. What chip would you be replacing with one of these? I know the pinouts of the chip should most likely match the chip you are replacing.


----------



## imran27

I'm building a DAC/AMP. Hence everything required to properly implement these OP amps is under my control


----------



## therealbene

OpAmp gurus, I need some advice. I'm trying to improve the sound of my iBasso DX90. I'm registering the help of an experienced technician since I'm a total newbie. 
The DX90 has 4 OPA1611A inside it. I'm thinking to replace it's OPA1611A chips with ADA4627-1BRZ. Will the sound be better? Or would the OPA4637 be better suited for the task? 
I want a wider sound stage, sweeter "analogue" timbre and weighty (bass). Will the ADA4627 be a suitable chip? I'd really appreciate your suggestions.


----------



## imran27

You could give OPA1641 a try, has a great soundstage


----------



## Mad Max

ADA4627-1B is a greater current hog than 1611, so battery life will suffer.  It could end up sounding a pinch better and in the manner you would like, sure, but 1611 is plenty hi-fi as it is, plus iBasso know how to use that chip well.  I would suggest just leaving the 1611 there.
 For the sound you seek, DX90 probably wasn't a step in the right direction.  ESS DACs like the one in the DX90 are probably not the right choice for a more analogue sound, but that's just speculation on my part based on what a few guys have told me about DACs they tried with ESS chips.


----------



## Magic77

I am currently now using the OPA627PA in my headphone amp, definitely the best opamp I have ever heard. Other good ones are the OPA1641, OPA827 and OPA134. The OPA627PA are $25 each, but worth every penny in my opinion.


----------



## imran27

So you got two opinions now, OPA627 as the best and OPA1641. I haven't tested but from what I know the OPA1641 has better soundstage and is cheaper too


----------



## Magic77

imran27 said:


> So you got two opinions now, OPA627 as the best and OPA1641. I haven't tested but from what I know the OPA1641 has better soundstage and is cheaper too[/quote.
> 
> Yes, I have to say the the OPA627 is really awesome and sounds great with my amp. I don't intend to swap it out any time soon::But, I do agree that the OPA1641 is also great. I just had to try the OPA627 given the high reputation it has. I would also try the OPA827 which goes for $10 for each and supposedly rivals the OPA627.


----------



## imran27

I'd jump in with some sort of distraction....
  
 I tried the ASUS Zenfone 5 (A501CG) recently with the M40x (I personally own HTC Desire 820, it sounds really good)
  
 The sound of the ASUS Zenfone 5 was superb. Far, Far better than my HTC Desire 820 (DS). It sounds way more natural and bass and treble extensions are great.
  
 What DAC chip and opamp it might be using? It is very good and if someone owns a good DAC/AMP he/she may give a comparison of sound.
  
 Intel Atom does not have an inbuilt audio DAC (AFAIK).


----------



## P701

imran27 said:


> I'd jump in with some sort of distraction....
> 
> 
> 
> ...



 

If you tried the headphones straight from the phones audio output, maybe it is due the difference in the phones output impedance?
From my own personal listening experience the output impedance has much greater impact on sound than DAC chip or OP amp itself.
This could be found out, if you had a headphone amp and you would put it between the phone audio output and the headphones and listen if they sound much different anymore, but I dont know if you actually had already done it like this?


----------



## zhangsiyan12134

I have a question about Op-amp replacement. When I compared two schematics, I noticed that ne5534 has three extra signals(COMP, COMP/BAL and BALANCE) than normal signal OP-amp. Can I use any OPA series (like OPA111) to replace ne5534?
	

	
	
		
		

		
			




  
 Thanks everybody.


----------



## Stillhart

Hi folks,
  
 I'm going to be upgrading my Adcom GDA-600 DAC soon and I need a little help.  The thread I'm following (HERE) is like 5 years old so I'm coming here to beg for info.
  
 Basically, I'm looking for the opamp shown here:
  

  
 It's an OPA627AU on a BrownDog 020302 adapter and DIP socket.  The best I could find is two Opamps mounterd on an adapter with a slightly different model name (020302A).  Can anyone verify for me if that's the same thing?  I'd rather not drop $100 on two opamps to discover it's not what I need...
  
 Thanks!
  
 EDIT - I think I found a post later on that confirms they're "dual opamp packages".  So yeah, this can probably be disregarded.  :-D


----------



## Wishmasterx

Have someone experience with bias to class A on OPA128SM? How much is best or maximal value for this opamp?
I have good result with bias on OPA627, but OPA128 have only 10mA Current Output (OPA627 have 45mA).


----------



## palermo

Hi folks, anyone tried ADA4075-2 as LPF or I/V converter ?

 how it compare to ADA4841-2, ADA4896-2 and ADA5899.

 ADA4075 can be found on CL Theorem 720 and Yulong DAC, so it quite good for filtering on DAC. I thought it popular for audio purpose, but never to be discussed in this thread.


----------



## Mad Max

4075 is a very nice chip, though I haven't used it much.  Versus 8599?  I've only tried the single version so far, 8597, and I found 4075 to fall short of 8597 in soundstaging and bass in my old Compass DAC.


----------



## palermo

mad max said:


> 4075 is a very nice chip, though I haven't used it much.  Versus 8599?  I've only tried the single version so far, 8597, and I found 4075 to fall short of 8597 in soundstaging and bass in my old Compass DAC.


 
  
 thanks for your replay Max, 
  
 Yes I familiar with 8599. As seen on my sig, ALO Island turn to different beast after being modded. 
	

	
	
		
		

		
		
	


	




 It give a soundstage that I cant find on fiio dap I tried. 
  
 I like to mod a DAP, it uses pcm1792A dac, i/v, lpf and gain uses opa1612 and buffer buf634. all opamp get +-7v supply voltage. the complaint are slight narrow soundstage and being to forward for my taste.  
  
 I plan to use muses8920 on lpf and gain, it would give warm and articulate vocal. the critical point is choosing the I/V converter, it has to give me a sense of wide and deep soundstage.
  
 my option are something like ADA4841-2 or ADA4075-2. would you help me, which one I have to choose.


----------



## Nazo

EDIT: Moved to a more appropriate separate thread.


----------



## Libertad

Just got in the house a burson audio supreme op amp and its a huge improvement from the JRC4580D that came with my card


----------



## wiz2596

hi guys
  
 I own a sound blaster zxr and currently 2 LME49710HA and 2 LME49720HA opamps on my card, I'm looking for the best possible quality for music listening especially metal music and rock but Im not much experienced in opamps, so I really appreciate if u could guide me on this.

regards


----------



## wiz2596

Someone?


----------



## Apocalypsee

wiz2596 said:


> Someone?


 
 I'm using the same combo on my X-Fi Titanium HD. I don't think any other opamp combo would beat this


----------



## wiz2596

not even muses 02? Im planning to buy them but I wanted to know if anyone in here got them and if so, how do they perform?


----------



## wiz2596

hi guys I'm a bit confused about speaker position feature in the sound blaster zxr, could it be possible somebody more experienced in this matter could guide me on this, my speakers are not in ideal positioning due space issues in my room and I want to use this feature to maximize my sound performance, but not sure about "ideal listening position" this manual stated, how should I do this measures?


----------



## yeahx

I have been wondering if it would be worth changing the opamp in the cMoyBB I just built a few weeks ago. I have tried doing some searches and have no idea which ones would be good to try. Preferably ones that would not require a mod to fit but I guess I would consider it. Really like soundstage and prefer neutral sound I think. Some bass, but detailed and not silly.


----------



## LingLing1337

Its always worth a roll! Been a while since I built a cmoy. But lm4562 or lm47920 is always a good choice for clarity and neutrality, maybe tending a little lean. AD8620 had a fuller, warmer sound.


----------



## SpudHarris

lingling1337 said:


> Its always worth a roll! Been a while since I built a cmoy. But lm4562 or lm47920 is always a good choice for clarity and neutrality, maybe tending a little lean. AD8620 had a fuller, warmer sound.




In a cmoy the AD8620 takes some beating as it is really nicely balanced 'fairly' reasonable to buy and not too current hungry. I personally love AD744 chips but they are not readily available anymore and man they drink the juice.... I have these in my P4 and Fi-quest amps.


----------



## yeahx

Thanks guys! Does it matter if they are the ARZ or BRZ because the only difference I see is B is double the price. $15.35 is a decent price for one of these?


----------



## SpudHarris

You won't hear twice the difference but I'm a bit anal about stuff like that so always bought the BRZ's where possible. The marginal differences will be on the spec sheets...


----------



## DingoSmuggler

yeahx said:


> Thanks guys! Does it matter if they are the ARZ or BRZ because the only difference I see is B is double the price. $15.35 is a decent price for one of these?


 
 B-spec opamps are either higher binned, or specifically trimmed for _better DC specs_. AC performance is what matters for audio.
 For typical audio applications, I can't see a valid reason to pay the extra, go with A-spec.


----------



## yeahx

dingosmuggler said:


> B-spec opamps are either higher binned, or specifically trimmed for _better DC specs_. AC performance is what matters for audio.
> For typical audio applications, I can't see a valid reason to pay the extra, go with A-spec.


 
  
 That is good to know because that's what I would probably be ordering out of the 2. I might see if any others seem good but thats probably the one from the sound of it. The OPA2277P chip included in the kit sounds pretty good, just wanted an upgrade option.


----------



## leeperry

yeahx said:


> Does it matter if they are the ARZ or BRZ because the only difference I see is B is double the price.


 
  
 Higher grade chips usually behave better when rolled blindly, at least that's the opinion of a few crazy rollers and I would agree.


----------



## AudioCats

how does the muses8920 compare to AD8620 and AD8599, in a voltage gain stage?
 normal supply voltage, +/-10~12v


----------



## bung_karno

wiz2596 said:


> not even muses 02? Im planning to buy them but I wanted to know if anyone in here got them and if so, how do they perform?


 
 read page 299-310


----------



## jcx

I found a correlation in a CMOS op amp for pH sensor buffering - the lower Vos spec parts had the best CMRR/CM linearity - it was a very pretty parabolic function of Vos over several batches of parts - the CMRR boost was enough to make the low Vos  part meet our spec even though the datasheet speced CMRR didn't
  
 of course you have to talk to the manufacturer's engineers, learn whether the part is selected or trimmed in production to decide to put your confidence in the correlation
  
  
  the "lesson" for this thread - some "conventional engineers" do select parts for the application, often going beyond datasheet info for the application circuit's, product's performance demands
  
 if you want to "improve" a circuit with op amp rolling you should expect to need to know the circuit and the op amp's used and available for rolling at least as well as the product design engineer
  
 otherwise blind op amp rolling is just a variation on the million monkey theorem https://www.google.com/#q=million+monkey+theorem


----------



## Mad Max

jcx said:


> ...  the "lesson" for this thread - some "conventional engineers" do select parts for the application, often going beyond datasheet info for the application circuit's, product's performance demands ...


 
  
 Not unheard of, at least to me.
  
  


> ... otherwise blind op amp rolling is just a variation on the [infinite] monkey theorem...


 
  
 That is stated, just not in the same exact words as you have.


----------



## jcx

the "infinite" reformulation doesn't capture the idea I am after - with infinite monkeys you certainly get Shakespeare - lost folio and all - in fact if you number your monkeys some sequential run of them do it on their 1st keystroke read in sequence
  
 with "just' a million monkeys typing at a physically practical rate you have to wait long enough to see if protons really decay or not


----------



## wiz2596

What do u guys think about the muses 02 opamp for sound blaster ZXR?


----------



## Jnjy

jcx said:


> the "infinite" reformulation doesn't capture the idea I am after - with infinite monkeys you certainly get Shakespeare - lost folio and all - in fact if you number your monkeys some sequential run of them do it on their 1st keystroke read in sequence
> 
> with "just' a million monkeys typing at a physically practical rate you have to wait long enough to see if protons really decay or not



Im lovin this. Go on


----------



## Renato6

When replacing the Muses02 op amp has anyone noticed a sound quality difference between directly plugging it into the board as opposed to using a Gold-Plated Socket such as the following on a Little Dot 1+ Amp?
  
 http://www.ebay.com/itm/6pcs-New-8-Pin-Gold-Plated-Socket-For-OP-AMP-DIP8-/261179539940?ssPageName=ADME:L:OU:CA:3160


----------



## gibosi

renato6 said:


> When replacing the Muses02 op amp has anyone noticed a sound quality difference between directly plugging it into the board as opposed to using a Gold-Plated Socket such as the following on a Little Dot 1+ Amp?
> 
> http://www.ebay.com/itm/6pcs-New-8-Pin-Gold-Plated-Socket-For-OP-AMP-DIP8-/261179539940?ssPageName=ADME:L:OU:CA:3160


 
  
 I didn't notice any difference in sound. But the only reason to use the socket is it makes it a lot easier to insert and remove opamps. So if you expect to keep rolling opamps, use the socket. If you expect to leave the MUSES02 in forever, there is no reason to use it.


----------



## Meddlesome Duck

Hi Everyone,
  
 I recently purchased a little dot i+  I've been playing around with different tubes and op-amps, I've been reading about using a adapter to allow for two single op-amps instead of the singular dual channel op-amp. What would be the benefits of using this setup, without any technical understanding I can imagine how using a chip for each channel could help produce a better sound but would this be the case when using an adapter. I'm assuming there would be some constraints possibly in power by running an adapter and two chips through a singular chip configuration. 
  
 Thanks.


----------



## Renato6

gibosi said:


> I didn't notice any difference in sound. But the only reason to use the socket is it makes it a lot easier to insert and remove opamps. So if you expect to keep rolling opamps, use the socket. If you expect to leave the MUSES02 in forever, there is no reason to use it.


 
  
 Great, thanks. I guess if t doesn't hurt the performance I'll leave it in.  That is until I have a reason to open up the amp again!


----------



## wes1099

I recently aquired a set of IEMs that sound significantly better when plugged into an amp, but there is one issue. All of the op-amp chips I have distort the lower bass regions. Any suggestions for a chip that won't distort the bass? My OPA2604 is the best out of the 5 I have but the distortion is still quite noticeable, just not as much as the other chips.


----------



## jincuteguy

What are some of the best OPamps for Creative X7? What about the Muse01 and 02? Are they the best Opamp u could buy atm? And whre could I get them besides Ebay?


----------



## psygeist

Any other OPAMP better than MUSE01 ? I got like 2 MUSE01 and 1 MUSE02.


----------



## SpudHarris

psygeist said:


> Any other OPAMP better than MUSE01 ? I got like 2 MUSE01 and 1 MUSE02.




It really depends where you are using them. For me, blind rolling the 01 into most of my portable amps has given great results. That's not to say however, that an amp/circuit designed around a specific OpAmp such as the much cheaper OPA132 will not better this. There are mighty fine OpAmps out there at half (or less) the price of genuine Muses 01/02. I really like the LME49990, AD743 + 797 (if you can get them) and OPA602.


----------



## jincuteguy

psygeist said:


> Any other OPAMP better than MUSE01 ? I got like 2 MUSE01 and 1 MUSE02.


 
 Where can you buy the MUSE01 and 02?


----------



## psygeist

spudharris said:


> It really depends where you are using them. For me, blind rolling the 01 into most of my portable amps has given great results. That's not to say however, that an amp/circuit designed around a specific OpAmp such as the much cheaper OPA132 will not better this. There are mighty fine OpAmps out there at half (or less) the price of genuine Muses 01/02. I really like the LME49990, AD743 + 797 (if you can get them) and OPA602.


 
 I have others tried few others, OPA2227, OPA627AU and AD8620ARZ. AD8620ARZ was a bit too bright.
  
 LME49990 is considerably cheaper (2x$4)
 http://cimarrontechnology.com/lme49990ma.aspx
  
 I suppose BRZ version is better ? (2x$11)
 http://cimarrontechnology.com/ad797brz.aspx
  
 Can't seem to find OPA602 on cimarron. Is similar to OPA627AU ?


----------



## psygeist

jincuteguy said:


> Where can you buy the MUSE01 and 02?


 
 I got it from ebay seller janeh2100
 http://www.ebay.com/itm/1PCS-MUSES01-High-Quality-Audio-J-FET-Input-Dual-Operational-Amplifier-/400418604577?pt=LH_DefaultDomain_0&hash=item5d3acf0621
 http://www.ebay.com/itm/1PC-MUSES02-High-Quality-Audio-J-FET-Input-Dual-Operational-Amplifier-Japan-/400418607953?pt=LH_DefaultDomain_0&hash=item5d3acf1351
 http://www.ebay.com/itm/1p-MUSES01-1p-MUSES02-High-Quality-Audio-J-FET-Input-Dual-Operational-Amplifier-/360599222400?pt=LH_DefaultDomain_0&hash=item53f5637880
  
 You can get it from korean ebay seller if you just want to be safe.
 http://www.ebay.com/sch/ICs-Processors-/4663/m.html?_nkw=&_armrs=1&_ipg=&_from=&_ssn=audinst
  
 Do let us know your impressions once you try them out.


----------



## pelopidas

I've tried all popular opamps in my Xonar in the last 4 years. I kept coming back to AD797 in I/V and 49720HA in buffer.
 Thats a pretty decent sound but it wasn't right. The desire to keep messing with it, straining to listen deeper into the recording leads to trying all kinds of opamp variations. 
 "its too sibillant.. the bass is flabby... where is the bass?..the soundstage is small or muddy..."
 Well, after playing around for 4 years, the solution is stupidly simple.
 The LME 49990, 49720, 49710, AD797 and all other awesome opamps need better bypassing.
 After reading these different fora for years, you will come across adding compensating capacitors in the 50pf range from the output to the neg feedback. 
 Did that. Didn't make me happy. Something else was wrong. Try adding 0.1uf from + to -... well that didn't do it either.
 The trick for me is to put 10uf on the chip from + to -. I use Silmic II because they are generally my favorite. Before, the 49990 in buffer would get between real warm and actually hot. Obviously oscillating.  Now it is barely above ambient. The AD797 sounded good in I/V but I kept wishing it had more Bass, more fullness in sound.

 What changed after adding the caps?
 1. Most noticeable is that the music has gained two octaves of bass. It goes so low, I had no Idea how much i was missing out on. Its low, low and full and rich and controlled and has volume that moves air.
 2. The separation of instruments, their definition and texture is much more visceral. Everything is locked in its place and there is clear separation. The locations of each sound are rock solid.
 3. The background has become black. I thought I used to know what that meant when people would say that music comes out of a black background and floats in space. It removes a haze that you couldn't put your finger on.

 So, anyone wondering about the AD797 and LME49990 absolutely need to try this cheap and simple mod. 10uf Elna Silmic II across the power pins of the opamp. Its the cheapest, fastest mod out there and has spectacular results.
  


 I cannot overstate how phenomenal this simple mod is. I will be trying different caps and bypasses soon to see what else can be achieved.


----------



## psygeist

pelopidas said:


> I've tried all popular opamps in my Xonar in the last 4 years. I kept coming back to AD797 in I/V and 49720HA in buffer.
> Thats a pretty decent sound but it wasn't right. The desire to keep messing with it, straining to listen deeper into the recording leads to trying all kinds of opamp variations.
> "its too sibillant.. the bass is flabby... where is the bass?..the soundstage is small or muddy..."
> Well, after playing around for 4 years, the solution is stupidly simple.
> ...


 
  
 Which one do you have, xonar ?


----------



## pelopidas

the Xonar HDAV 1.3
 Probably the least of all Xonars right out of the box. After bypassing the output caps with wire, it opened up completely into something quite lovely. But, obviously, it wasn't good enough because I have been modding and swapping opamps from the beginning.
 Only two mods sofar have had an appreciable effect.
 1. bypassing output capacitors with wire.
 2. adding a 10uf Silmic II to the opamp + -
  
 If you have a pair of AD797B for your I/V, you must try adding 10uf Silmic to it. Perhaps other caps will also be as awesome. Ill let you know as I am now testing capacities and manufacturers to see what difference it makes.


----------



## fragger008

Hello all,
  
 First of all, thank you for these topics about tube rolling, opamp rolling, etc. on which we can find a lot of information, awesome !
  
 I'd like to ask a simple question : do you need to "burn in" an Opamp as we do for tubes ? And how to do it if necessary ?
  
 Thanks


----------



## pelopidas

Burn in for capacitors? Absolutely.
 Burn in for Opamps... Well, I know that some think you need to. I personally don't know that I have ever heard a difference. I have listened for it but a new lme49720ha sounds the same as one I have used for years.
 If you can hear the difference and want to burn it in, then open foobar or some similar player and put a track on repeat. Chose something that has deep bass and lots of treble. Let that play over night.
 On my xonar, when im burning in capacitors on the opamps like i am right now, i turn off my headphone amp and turn the volume to 100. Let it do its thing for a while, come back, don't forget to turn the volume down and test with a familiar song.


----------



## pelopidas

10uf silmic II on both I/V and the Buffer sound really good. Very tube like. Very warm. I would not mind a bit more definition in the treble though. So here are the experiments to see if this sound can be improved:
  
 here are the test tracks I used:
  

 1. Arianna Savall – Preghiera  This tests sibyllance, 3d and locality.
 2. Gazpacho – Valeries Friend   A lot of cymbals, Prominent Vocals. Lesser Caps turn it into a screechy awfulness.
 3. thePhantom – Freeze   Deep Bass, synth cymbals
 4. Yosi Horikawa – Bubbles   Test coherence. Lesser capacitors become confused and it’s a mess.
  

*Silmic II*
  
 By itself is good enough. It is so deep and rich, I cant get away from my computer. The sound is thick and rich and full and enveloping and powerful. I feel the bass in my chest. The soundstage is deep, 3 dimensional, every instrument is locked into place, rock solid and separate from each other.
  
*Silmic II bypassed with 10nf MKP 1837*
  

 So I try the MKP 1837. Usually very good at cleaning up and “etching” the top end.
 In this case it is just harsh. Just the Silmic leave natural sibilance natural sounding, just the SSSS that is produced with certain words. The MKP 1837 make it a grating CHCHCHCHCH. Arianna Savall is too sibilant and Gazpacho is intolerable. This is not a successful bypass. Also it made the sound stage feel much less 3D. So I had to take those off.

  
*Silmic II bypassed with Silver Mica*
  

 My impression? I don’t know... tough to pinpoint. Only way i can describe it is that it sounds “lighter” in the treble area. Its not crisper, there is no sibilance, nothing etched but the top end sounds lighter in a soft way. Its not harming the soundstage much.  It is deep, with all the instruments and sounds floating in their proper location but the “softness” causes a slight loss of coherence. This becomes evident with songs like  “Bubbles” from Yosi Horikawa. Its as though there is a soft halo around the treble.
 This is a very very nice sound. I could live with this.
 The only sensible next step would be Teflon. So lets try those.
  
*Silmic II bypassed with Teflon*

 The soundstage is absolutely correct. There is no sibilance. The teflons seem to have brought that very last 2% of clarity to everything. Could I reliably A-B test and pick it out though? I don’t know. It is not harming the feel of the silmics. There is warmth and body. It preserves everything that the silmics do right but add clarity to the whole picture. But this is a very subtle addition. It is just.. right. This is very very good.
 All the micro-details are there, every shimmer from the cymbals is there. Gazpacho is great. The bass is fast. The voice is not screechy, The cymbals don't become a mess. Very dynamic. This is very very good.

  
  
*Elna Cerafine*
  
 not as good as silmic. There is magic missing. The clarity is nice, the tone seems correct. It’s just not as awesome. Its more fatiguing than the Silmics. The cerafines are not producing details that the silmics are not. It just seems accentuated. This is not better and I am missing the Silmics. Don't get me wrong, these are excellent sounding caps but just missing some weight and "magic" 
 The difference can be described as a 60 lb kid on a trampoline jumping 5 feet in the air. He goes up and comes down and up and down. Now imagine a 300 lb dude jumping 5 feet in the air on the trampoline. They both move the same distance but the impact felt by the trampoline is different. That is how this feels. The notes are there but its not taking you and forcing you to rock and tap to the rhythm.... it's optional. 
  
  
*Panasonic SEPF 390uf*
  

 So I thought it would be good to find out at what voltage the sockets were running at before using a 20V capacitor. My Xonar is at 16.7v from – to + so I am ok with these caps.
 There is more information in the music than with Silmic II. It is almost sibilant but it isn’t. It is just very very fast. You can hear every shimmer of cymbals. You can hear where on the cymbal the drum stick hits. All the micro detail is there. The bass is full and taught. It does not become confused.
 But.. that fat, warm, luscious bass from the Silmic.. I miss it. Perhaps it is colored but I want it.
 A perfectly cooked steak is delicious, but adding seasoned butter is good too.
 It is so clean it is addictive. It sounds like the silmic when bypassed with the teflons.
 Impression: Very clear, very clean, wide open, neutral. This is very very good.

  
  
*How about the buffer?*
  

 Current Setup
 AD797BRZ I/V with Panasonic SEPF
 LME49990 Buffer with Silmic II
 Fantastic. Amazing. I cant turn it off to test anything else. The bass is right. The mids are right. The treble is right. It is soooo fast but not etched. You are retrieving all the information there is to be had in a recording.
  

  
 SEPF on the I/V and the Buffer.
 This presentation is missing magic. Ariana sounds correct, but im not melting into the music, im not marveling. It is more 2D. It is slightly sibilant.  This combo is not as good.
 also, the LME49990 was definitely getting warmer.
  
  

 Next up, SEPF on lme49990 buffer and Silmic on the AD797 I/V:
 Not sibilant. Warm and musical. But I feel like im missing the extra detail from the SEPF on the I/V stage:
  
 Next up: SEPF back on the AD797 and a bigger silmic on the LME49990 buffer.
 390 uf for the I/V is not hurting anything. Lets see if 470uf on the buffer is ok.
 Result: it makes no difference except that it is huge and looks stupid. No benefit over 10uf.

  
  

 Next up LT1028A in buffer. No Cap: Bass is overblown, slightly flabby. It does not sound as liquid as the LME49990.
 There are resonances that are not quite right. Good detail retrieval. Chips are warm. need to add the Silmic

  
 With Silmic: Brings it all together. Bass is tighter. Smooths it out. Does not have the same sound stage as the LME49990. Seems more fatiguing. Not better.
  
 Next up: LME49720HA with Silmic. Really good bass. Not sibilant. Treble is well defined. Actually a very good opamp but not as good as LME49990.
  

*Current setup:*
 going back to Silmic with Teflon bypass on AD797 in I/V and Silmic on the LME49990 in the buffer.
 This is very very good. The sound stage is phenomenal. The musicality is phenomenal, the prat is phenomenal.
  
*my current recommendation:*
 if you have a xonar, put AD797B in the I/V stage and bypass it with 10uf Silmic II and a little Teflon. Alternatively, use a Panasonic SEPF. I have some 22uf ordered and will let you know if the smaller capacity makes a difference. Based on my experiment with the 470uf Silmic, I am guessing not.
  
 Put a LME49990 in the buffer stage and bypass it with 10uf Silmic II.
  
 This combo is really very very good.
  
 If anyone tries this out, let us know your impressions.


----------



## fragger008

pelopidas said:


> Burn in for capacitors? Absolutely.
> Burn in for Opamps... Well, I know that some think you need to. I personally don't know that I have ever heard a difference. I have listened for it but a new lme49720ha sounds the same as one I have used for years.
> If you can hear the difference and want to burn it in, then open foobar or some similar player and put a track on repeat. Chose something that has deep bass and lots of treble. Let that play over night.
> On my xonar, when im burning in capacitors on the opamps like i am right now, i turn off my headphone amp and turn the volume to 100. Let it do its thing for a while, come back, don't forget to turn the volume down and test with a familiar song.


 
  
 Thanks for your answer


----------



## Mad Max

pelopidas said:


> Burn in for capacitors? Absolutely.
> Burn in for Opamps... Well, I know that some think you need to. I personally don't know that I have ever heard a difference. I have listened for it but a new lme49720ha sounds the same as one I have used for years.
> If you can hear the difference and want to burn it in, then open foobar or some similar player and put a track on repeat. Chose something that has deep bass and lots of treble. Let that play over night.
> On my xonar, when im burning in capacitors on the opamps like i am right now, i turn off my headphone amp and turn the volume to 100. Let it do its thing for a while, come back, don't forget to turn the volume down and test with a familiar song.


 
  
 x2
 Same thing I used to do.
  
  
  
  


pelopidas said:


> 10uf silmic II on both I/V and the Buffer sound really good. Very tube like. Very warm. I would not mind a bit more definition in the treble though. So here are the experiments to see if this sound can be improved:
> 
> here are the test tracks I used:
> 
> ...


 
  
 Teflon is that good, eh?  I never thought of trying some out.
  
 I swear by 160V 0.1uF MKP1837, unless there's not enough room for it, then WIMA MKP2 0.1uF 100V.
 As a last resort, MKS4 0.1uF 63V, damn tiny caps, but not as good as MKP4 which are not as good as MKP1837/MKP1839.  However, note that I am talking about external gear, I've only ever used WIMAs on a soundcard, and that was years ago when I used soundcards at all.
 The results aren't quite the same with external gear.  MKP1837 beats anything in every way, sonically to me, except Soviet K42-Y2 PIO film caps.
  
 Try combing a Nichicon KZ with a Silmic II along with a film cap of your choice.  I put off combining electrolytics a long time ago and never got around to experimenting with them.  KZ has the best treble, and you love the bass of Silmic, so some combination of the two should make you quite happy.  Perhaps a 50V 100uF KZ with little 35V 10uF silmic?  Or maybe a 10uF KZ with a 100uF Silmic?  Making one cap 10x smaller than the other one helps with avoiding overlapping self-resonant frequencies, something like that.  If each capacitor's self-resonant frequency overlaps with the other, you get resonance at the opamp output or it oscillates or something, I forgot now.  The result is bad and should be avoided, basically.
  
 So far, Vishay 515D caps have given me the best bass I've heard from electrolytics, but the midrange and treble is unnatural.  Maybe you may like this one yourself.
  
 On external equipment, I've only liked those Panasonic Oscon caps on digital PSU rails, not analogue PSU rails.
  
 Nichicon KW is another one worth trying, though its bass sucks.


----------



## pelopidas

Update
 the 22uf SEPF arrived and I have had a chance to play around with them on the DAC as well as the amp.
  

  
 Left is the buffer from my "2 penny" amp. On the right is the 49990 with its SEPF tophat. 
 In I/V stage the 22uf SEPF is as good as the Silmic with teflon bypass. It is totally clean, clear, detailed, spacial, harmonically correct and not sibilant. The Silmic/teflon actually sounded too smooth. Don't get me wrong, it is a phenomenally good sound but Im not sure it is better than just a 1$ 22uf SEPF, plus the size is ridiculous.
  
 Here is another interesting find. The SEPF is ideal for I/V but its not the best thing for the buffer. The buffer looses what I can only describe as microdynamics. This is true for the DAC as well as the amp. In the above picture I tried a 470uf silmic and that also is not the right capacitor for this position.
 The amp benefits from having a Cerafine on it. This lets all the bass trough while being beautifully clear on the top end. It also preserves the microdynamics.
  


> I swear by 160V 0.1uF MKP1837, unless there's not enough room for it, then WIMA MKP2 0.1uF 100V.


 
  
 I did try the MKP1837 and was surprised that it sounded so strident and ear piercing. Perhaps I was being too impatient, and perhaps they need to burn in more. I will test them again and let them burn in for 100 hrs.
  
 The final flow that I am happy with (currently) is:
 DAC I/V AD797 w/ 22uf SEPF  ---> Buffer LME49990 w/ 10uf Silmic II  -------//-----> AMP I/V LME49990 w/ 10uf Cerafine ---> Buffer LME49600 w/ 10uf Cerafine


----------



## JamesBr

pelopidas said:


> 10uf silmic II on both I/V and the Buffer sound really good. Very tube like. Very warm. I would not mind a bit more definition in the treble though. So here are the experiments to see if this sound can be improved:
> 
> 
> 
> ...


 
  
 Super details! Thanks for the detailled informationo


----------



## jincuteguy

jamesbr said:


> Super details! Thanks for the detailled informationo


 
 These are better than MUSE01 and MUSE02?


----------



## SpudHarris

What about duals like this?



I'm new(ish) to bypassing but found some of these



and thought I'd have a play around tonight.....


----------



## pelopidas

Hi Spud!
  
 I am using the dual 49990 as well. Throw one of those caps on there. Be patient. This is my biggest problem. As you can see from my previous posts, I jumped around quite a bit and its not the right approach.
 I could call it an update, but I am back to all Silmic on the Xonar. Silmic on AD797 in I/V and Silmic on the 49990 buffer. I thought it would be good to go back to my original baseline and see what my opinion of it is now, compared to all the recent changed I heard.
 What I found out is the recommended 100 hour burn in for Silmic is a real thing. I thought, perhaps because these are so small it will go faster. Nope.
 Here is what happens with Silmic II:  first 4 hours are phenomenal, and then suddenly you wonder if there is enough treble. Was it missing it all along? 5-85 hours.. its pretty good but not what you remember. Bypass mania ensues... how to fix it.. to get it to what it was.. pass the 100 hrs mark and all is well again. Sparkly, sweet top end. Deep deep and tight bass. So much air. All instruments are perfectly placed in space. Basically what I said in my first post.
 So now I cant get myself to pull out the Silmics again.
  
 Please let me know your impressions of those muse bipolars. I was actually curious about those and would love to know what you think. Also, you need to try a Silmic II.
  
 What are you using it in? Amp? DAC?


----------



## Mad Max

Those bipolars contribute to a muted sound.  Bad idea, in my opinion.


----------



## SpudHarris

Thanks for the input guys, not tried anything tonight as we had a movie night with the kids 

I have stumbled across various MK Wima polypropylene in my stash (from when I was building cmoys). Using Opamps and buffers in my Ibasso built Fi-quest....


----------



## pelopidas

Hey Spud,
  
 nice opamp collection! I see you already have the LME49600 buffers in place.
 Do you have any AD797 in your collection? If so, why don't you try putting a Silmic II on those and a Cerafine on the buffers. Let it burn in for 100 hrs. I would really love to know what your opinion is on that combo.


----------



## SpudHarris

pelopidas said:


> Hey Spud,
> 
> nice opamp collection! I see you already have the LME49600 buffers in place.
> Do you have any AD797 in your collection? If so, why don't you try putting a Silmic II on those and a Cerafine on the buffers. Let it burn in for 100 hrs. I would really love to know what your opinion is on that combo.




Thanks pelopidas... Yes I have a few AD797's. I will get on it and report back.


----------



## theory_87

Spud, what buffer are you using in the last pic?





Currently using Signetics NE5534AN OBCA with 4* HA5002 and 2* buf634 on my mad dog fi.quest. Prefer ne5534 to muse01 & muse02 atm


----------



## SpudHarris

They are LME49600's. An absolute pain to fit in the standard DIP sockets. I bought some off eBay but they didn't fit so with the help of HiFlight I managed to make adapters...


----------



## theory_87

I can imagine it a pita to for those in.


----------



## SpudHarris

Got A couple of AD797BRZ's sorted last night with great results. Imaging and soundstage seem greatly improved. The caps were from a stash that came with some pcb's I bought a few years back. Still not 100% proficient soldering those tiny ceramics...


----------



## SpudHarris

theory_87 said:


> Spud, what buffer are you using in the last pic?
> 
> 
> 
> ...




Are there more than one make of NE5534AN?


----------



## theory_87

Yup. I know Phillips bought over Signetics, and there is JRC and TI who make them too. Signetics ne5534/5532 made in the 80s are the best sounding version and may be one of the best sounding opamp ever according to most including Dr. Xin. The one I had are made in 1983


----------



## SpudHarris

Are your OBCA adapters for the 5534's the same as this? I made these years ago for AD744's.... Been on the OpAmp rolling/modding wagon for a while


----------



## theory_87

spudharris said:


> Are your OBCA adapters for the 5534's the same as this? I made these years ago for AD744's.... Been on the OpAmp rolling/modding wagon for a while


i cut the leg and solder the resistor direct to the opamp. But you can use the adapter for ad744 for ne5534 since their pinout is the same.


----------



## SpudHarris

Awaiting delivery of a pair of 1982 made Signetics NE5534AN to try out


----------



## theory_87

spudharris said:


> Awaiting delivery of a pair of 1982 made Signetics NE5534AN to try out



 will like to know how you think about it


----------



## SpudHarris

Still waiting on my 1982 5534AN's but a couple of others arrived today... One of them is Raytheon! Never had a chip marked with this, only tubes.



If the 1982 made OpAmps are better than these, I am going to be very, very happy. I am amazed how great these sound, I will be auditioning all evening. This is one of those very rare occasions where something great doesn't cost the earth.

Thanks theory_87


----------



## BucketInABucket

Any idea what kind of op-amp can replace the LME49710s in this circuit? So far, LME49990s are proven to work. Thanks!


----------



## OJNeg

Love the collection Spud. Head-Fi needs guys like you.


----------



## theory_87

spudharris said:


> Still waiting on my 1982 5534AN's but a couple of others arrived today... One of them is Raytheon! Never had a chip marked with this, only tubes.
> 
> 
> 
> ...



 glad to be of help. I never imagine i will prefer ne5534 over muse01/02 considering the price difference. Will be interesting to hear your opinions on the different make ne5534 since i never try other makes ne5534.


----------



## pelopidas

Can you describe the difference between the muses and 5534? Also, how do the 5534 compare to 49990 or other common opamps.
  
 I have not yet had the chance to listen to a 5534 and am now curious


----------



## SpudHarris

Hmmm, not a massive amount of difference to my ears. Both are amazing OpAmps but with the OBCA mod on the 5534 I am favouring them slightly more than the Muses01 (my favourite of the Muses). I am astounded that after so many years rolling and tweaking that I have only just stumbled over this.

I tried the AD744 OBCA a while ago (which was great) but for some reason never tried the 5534 with the same pinout. The Muses01 is an amazing OpAmp and I think it has a very slight advantage over the 5534 for male vocals but this is a personal preference as I prefer them slightly more forward in presentation but generally I am finding the 5534 more musical which suits my HD800's to a tee....

If you take into account the price of the 5534 it's an absolute "golden nugget" not to be missed. Remember though, the OBCA mod is the magical mod that turns this "sows ear into a silk purse"

Man, don't you hate cliches.... I try to avoid them like the plague


----------



## pelopidas

Looking at the pictures of your 5534 you both have different mods with the resistors

 The 7.7k is Class A biasing if i understand correctly.
 Spud, can you explain how your mod works? It looks like you are bypassing the output and turning the comp + (+V) into an output.
 I am trying to wrap my mind around what is going on here but I dont get it 
	

	
	
		
		

		
			





. Please explain and help me.
  
 I also ordered some NE5534AN to test out here, but I am unsure of what is happening with the OBCA. Also, it is probably just the picture, but are the ends of the resistor touching between pin 6 and 7?


----------



## SpudHarris

I think our mods are the same but you can't see the detail on theory_87's.... I made adapters so I could use with both 744 and 5534 but completely forgot about the 5534 and never actually got around to buying any until recently.

OBCA is Output Bypassed Class A so you are correct. I'm no expert, I just carry out recommended mods. The pins of 6 and 7 do not touch.


----------



## pelopidas

I was reading some others who had done this mod and were generally pleased with it
  
 http://www.head-fi.org/t/133784/opa627-v-sa5534an-obca-impressions-sm3
  
 They did note that there was some reduction in detail. Have you noticed this? How big of an effect is there?
 As you can tell, these are questions from someone who is impatiently waiting for his own 5534s to arrive.


----------



## theory_87

Nope. Infact i find everything improve slightly compare to unmodified ne5534an. Not day and night on my humble iem but nevertheless still noticeable.


----------



## Lohb

Is there anything like the ADA4637-1BRZ that will work with an altoid amp ?
 Friend found LME4562 too brittle in the long-run.


----------



## pelopidas

Hi Lohb,
  
 there are a few parts to this answer.
  
 What impedance headphone is your friend using? The LME 4562 is rated to drive 600 ohm and can do 26 mw per channel. (high voltage, low current)
 this will not be ideal for for earbuds or anything in the low ohm range ( they go down as far as 16 ohms) (high current required to drive, voltage less so)
 The quickest and simplest fix would be to put a JRC 4556 in there. It can drive 150 ohm and can do 70 mw. This is a much more robust opamp for a cmoy.
  
 However, from my experiences with cmoys, the rise in distortion, from using a lower impedance headphone than is ideal, does not really contribute to a brittle sound. That is usually a result of the wrong type of capacitor. I don't know what variation of cmoy in a tin you have, but you either have a resistor based voltage divider or an IC based one. With the resistor voltage divider, you will have 2 electrolytic capacitors of the same value on the board. With an IC based one, you might only have one capacitor. If you "cheap out" on these you will have all kinds of maladies. Put in Jamicons and it will sound like your ears are full of cotton, just absolutely dead. Put in Panasonic FC and it will have a fatiguing top end that will make your ears bleed. Brittle, sybillant but otherwise dynamic. The safest bet is Elna Silmic II. Great bass and sweet, detailed top end.
  
 If your friend wants to leave the board as is, get a 10uf Silmic II and solder it directly onto the LME 4562 + -  This will revolutionize your LME4562. You could also use the SEPF 22uf which is even smaller and sounds just about as good.  Other capacitors do not have this magic. I have tried ceramics, all types of film all the way up to huge 22uf film capacitors. So try either the Silmic or the SEPF.


----------



## Lohb

pelopidas said:


> Hi Lohb,
> 
> there are a few parts to this answer.
> 
> ...


 
 Hi there he will be using 16-32 ohm earphones and headphones.
 I think JRC 4556 in there will be easiest for him.


----------



## pelopidas

Is he using a single 9v battery or two 9v batteries? 18v sounds a lot better. 
Also, if the sound continues to be harsh with the 4556 it is most likely bad capacitors. 
The difference between opamps is much more subtle than the difference between capacitors.
Can you provide a picture of the amp so we can see the components?


----------



## Lohb

pelopidas said:


> Is he using a single 9v battery or two 9v batteries? 18v sounds a lot better.
> Also, if the sound continues to be harsh with the 4556 it is most likely bad capacitors.
> The difference between opamps is much more subtle than the difference between capacitors.
> Can you provide a picture of the amp so we can see the components?


 

 He is using BioScioenceGeek Altoid which is regarded as one of the better ones. Yes, 18 volts.
 4562 always Sounded kind of detailed/fast but icy/brittle.


----------



## pelopidas

Can you find out the make of the capacitor? It looks like a cheap one in the pics I found.


----------



## burdie

Guys, need to ask a question on LME49720ha metal can version.
 Recently I soldered lme49720ha to 2 units of to9 to dip8 socket, and 2 units solder directly to dip-8 socket.
 I am using Matrix HPA-3B headphone amp and I swap the stock lme49860 to 49720.
 The problem I encounter is when I used the direct dip-8, my amp will auto off (protection) if I am using high gain (20db), low and mid gain have no problem at all.
 The TO99 to dip-8 adaptor works on all gain setting. All opamp purchased at the same time from one single supplier.
 will it be the socket problem or I am just unlucky to receive faulty opamp, or this is common problem on metal can?
 Thanks


----------



## pelopidas

Perhaps its not making good enough contact? The metal can legs are a bit thinner than regular DIP socket legs. Perhaps sanding the legs to make sure they are super clean and make sure you have positive contact in the socket. Otherwise.... solder it to a dip socket and try it then?


----------



## pelopidas

Well, my Signetics NE5534AN arrived. I ordered 4, which was a good thing since one was a dud. It is noisy, even though music comes through.
 I can't test it in my heaphone amp without rebuilding it since it produces 120mv of offset. Running the LME49990 in the headphone gives me 0.3mv offset.
 So I am evaluating it in the buffer position of my DAC.
 My first impression: Wow, this is much better than 30 year old tech has any right to be 
 Male vocals sound really good. It is a melodic opamp. The Bass is huge!
 After some careful listening I noticed that the bass is wooly, not taught. So at this point I put a 22uf SEPF on the + - and this tightens up the bass. Now it is clean and tight but DAMN its a lot of bass.
 It sounds like someone turned on the Bass boost on a cmoy.
 So compared to the 49990 in the buffer position i would say that it is good if you want FAT BASS. It is fast enough for any musical genre but its not quite my taste. 
 I listen with an HD650 and the bass overwhelms the music. At first it sucks you in but soon you get bass fatigue. It does not seem as airy either but that can be because of the overwhelming bass. 
  
 Next up: Try it will a different capacitor. After that I will try the Output Bypass Mod.
  
 Spud! can you recommend the correct resistor value for the mod? It looks like yours is 2.2k. Is there a reason for that value, or will anything in a certain range work?


----------



## amit_talkin

Guys, need some suggestions. What would be best suitable for bass lover? I am gonna replace 3 of stock op-amps on my xonar essence stx.
 My M50x arriving in 2 days. I miss that "mega bass" feeling which sony had with their walkman series. especially with w800i.


----------



## burdie

pelopidas said:


> Perhaps its not making good enough contact? The metal can legs are a bit thinner than regular DIP socket legs. Perhaps sanding the legs to make sure they are super clean and make sure you have positive contact in the socket. Otherwise.... solder it to a dip socket and try it then?


 
 The contact is good, I solder it directly to the dip socket. However, I mix 2 dip-8 direct solder metal can with the good to-99 to dip-8 adaptor (same opamp) , and noticed that only one direct solder metal can causing the auto off. This particular one cannot run at high gain and it uses 'cheaper' dip-8 socket. It may be the dip-8 socket problem? I need to order new socket to confirm.


----------



## imran27

Has anyone done a comparison of TPA6120A2 with the conventional opamp+buffer setup?
  
 I am thinking to use it as output stage+AMP after a PCM5102A DAC chip. It looks good and some people on head-fi have reported it to be amazingly good. Though they also say that it might not be good enough for a BA IEM (I am planning to use with Planar magnetics a.w.a. BA, tricky design).
  
 Also, if not TPA6120A2 then the conventional opamp + buffer solution I have in mind is with an AD opamp, since I want it to have an airiness in sound and good instrument separation, though I am not sure which buffer should I pair with so that I get very low output impedance and a pretty high drive strength too. I often go to headphone meetups where I will drive everything including AKG's hard to drive 'phhones to the over-sensitive multi-armature BA's like ATH-IM0X or Shure and also planar magnetics.


----------



## pelopidas

Lme49600 is the buffer you want.


----------



## imran27

Great then, for the differential AMP I will consider using OPA1612 or OPA2228. I hope it provides a clean, clear and natural sound with good bass and treble extension and great details. I just want a good airy soundstage and good instrument separation.


----------



## Mad Max

imran27 said:


> Great then, for the differential AMP I will consider using OPA1612 or OPA2228. I hope it provides a clean, clear and natural sound with good bass and treble extension and great details. I just want a good airy soundstage and good instrument separation.


 
  
 2-3x 49600 per channel then? Haha.


----------



## imran27

mad max said:


> 2-3x 49600 per channel then? Haha.


 
 Haha
  
 2x in parallel at the output would increase current drive and decrease the output impedance also 
	

	
	
		
		

		
			




  
 OTOH, I think a buffer is a must if I want a direct coupled output with no capacitors. If someone has tried an amp with a direct coupled (DC coupled) output with no capacitors and buffers then please let me know how it performs compared to a buffered output.


----------



## imran27

Couple of months ago I bought a PCM5102A based USB DAC from China (aliexpress), it has a headphone OUT and a LINE OUT. Headphone OUT uses AD8397 at single ended supply ~VDD=3.5V. So in order to just roll this with another opamp I ordered OPA2365, it works at that voltage fine but has a lower PSRR, which means I might need to add another bypass cap over it's pins. It sounds good for now, actually just satisfactory, just slightly better than my HTC Desire 820 Dual SIM.
  
 I hope OPA2365 makes a difference, once I roll it I will let you know the first listening experience and also how it sounds after completing a week in that circuit. (The amp circuit actually is a Cmoy circuit)
  
 What are the general impressions on OPA2365?


----------



## interface95

Looking for a opamp i found these cheap opa2107
 http://www.ebay.com/itm/171359245722?_trksid=p2045573.m570.l5999&_trkparms=gh1g%3DI171359245722.N36.S1.R1.TR1
  
 do you think they are fake?


----------



## SpudHarris

Never heard of 2107's being counterfeit, they've sold a lot and the company has good ratings. I'd get them....


----------



## leeperry

interface95 said:


> Looking for a opamp i found these cheap opa2107
> http://www.ebay.com/itm/171359245722
> do you think they are fake?


 
  
 Funny, as I was about to order a bunch of http://www.ebay.com/itm/391247632903
  
 OTOH those writings look so fake http://www.ebay.com/itm/271519342188


----------



## Mad Max

The chips in that first link could be fake.  The second one matches TI's printing, no guarantees though, especially at that price, unless they bought a few thousand from a distributor or TI or something.


----------



## leeperry

Apparently MA & MAX come with different markings but anyway I'll just get them off digikey in order to ensure that I don't buy vintage 5534's with fake writings ^^
  
 Gotta love fake BB holders for metal canned 6xx's on ebay, priceless hah.....especially as they should be light gray and they're black hah.


----------



## pelopidas

If you're looking for airy and transparent sound, I would pass on the opa2107. 
Get the 49990. It is not expensive and is fantastic.


----------



## Mad Max

I can no longer find sellers carrying the adapter shown below, the one that has the 797 soic chips next to each other.
 Anyone know who carries it these days?  I only have one that I put OPA209s on.
  
  


madwolf said:


> ...


----------



## palermo

Finally find a nice combination on alo the island. CS4398 - AD8599 as LPF - AD8599 as gain (+BG Nx HQ 0.47uf at 4-8). sounds spacious yet maintain intimate vocal, smooth and detail.


----------



## pelopidas

So I just upgraded my computer to windows 10 and I swear it sounds differently. I checked all the settings and put it all on 24/192. I'm still using Foobar.
 You know that tension you get in your shoulders when you put a crap opamp in or somehow some settings get messed up? The sound stage feels different. I detect some harshness that was not there before.
 Are there some settings I am unaware of?
 This might be a deal-breaker with windows 10 if I can't get it sorted. Any ideas?


----------



## Mad Max

Install Gentoo instead.


----------



## psygeist

pelopidas said:


> So I just upgraded my computer to windows 10 and I swear it sounds differently. I checked all the settings and put it all on 24/192. I'm still using Foobar.
> You know that tension you get in your shoulders when you put a crap opamp in or somehow some settings get messed up? The sound stage feels different. I detect some harshness that was not there before.
> Are there some settings I am unaware of?
> This might be a deal-breaker with windows 10 if I can't get it sorted. Any ideas?


 

 Use ASIO plugin if your soundcard supports that.


----------



## psygeist

mad max said:


> Install Gentoo instead.


 
 The guys at the bleeding edge are all over Arch Linux.


----------



## JamesBr

mad max said:


> Install Gentoo instead.


 
 +1


----------



## zilch0md

Here's another discrete op-amp - this one using surface-mount components and it's more affordable than others I've seen.
  
 They offer it as a dual or as a single...
  




  
 http://www.highendcity.com/discrete-opamp-dual-type/
  
  
  
  




  
 http://www.highendcity.com/discrete-opamp-single-type/
  
 Mike


----------



## imran27

imran27 said:


> Couple of months ago I bought a PCM5102A based USB DAC from China (aliexpress), it has a headphone OUT and a LINE OUT. Headphone OUT uses AD8397 at single ended supply ~VDD=3.5V. So in order to just roll this with another opamp I ordered OPA2365, it works at that voltage fine but has a lower PSRR, which means I might need to add another bypass cap over it's pins. It sounds good for now, actually just satisfactory, just slightly better than my HTC Desire 820 Dual SIM.
> 
> I hope OPA2365 makes a difference, once I roll it I will let you know the first listening experience and also how it sounds after completing a week in that circuit. (The amp circuit actually is a Cmoy circuit)
> 
> What are the general impressions on OPA2365?


 
 The headphone OUT is actually a single low voltage supply Cmoy with a 1000uF cap coupling capacitor on the output.
  
 Any comments on the OPA2365?


----------



## palermo

@imran27 
 For headphone out, you need an opamp with extra current output. AD8397 is pretty good for that job due its 230 mA current peak. other opamp that could be used is LMH6643, which has single supply voltage design, but lower current output, @75mA.
 Sorry dont have experience to OPA2365


----------



## hoshiyomi

you are likely going to find more improvement paralleling more capacitance to the 1000uF output cap, or replace with a large bipolar cap. (this assumes you are not limited in physical space)

otherwise work on the decoupling for the output opamp, get some tiny caps as close to the power pins as possible.



imran27 said:


> imran27 said:
> 
> 
> > Couple of months ago I bought a PCM5102A based USB DAC from China (aliexpress), it has a headphone OUT and a LINE OUT. Headphone OUT uses AD8397 at single ended supply ~VDD=3.5V. So in order to just roll this with another opamp I ordered OPA2365, it works at that voltage fine but has a lower PSRR, which means I might need to add another bypass cap over it's pins. It sounds good for now, actually just satisfactory, just slightly better than my HTC Desire 820 Dual SIM.
> ...


----------



## imran27

Using larger caps on the supply pins and and a larger bipolar electrolytic cap for the output coupling, that's worth a try


----------



## Tambourine Guy

Looks like there is a new opamp in town.


----------



## Mad Max

That size.  Nope.
 Not happening.


----------



## FritzS

hoshiyomi said:


> you are likely going to find more improvement paralleling more capacitance to the 1000uF output cap, or replace with a large bipolar cap. (this assumes you are not limited in physical space)
> 
> otherwise work on the decoupling for the output opamp, get some tiny caps as close to the power pins as possible.


 

 Unfortunately the BlackGate NX 1000 uF 25V are unavailable - this was the best in this case.


----------



## Mad Max

fritzs said:


> Unfortunately the BlackGate NX 1000 uF 25V are unavailable - this was the best in this case.


 
  
 DC-blocking cap, I assume?  Wouldn't it be better to use DC-blocking WIMA film caps?  That's what portable amps often use.  Pro audio equipment use SMD film caps of some kind for that as well.


----------



## Audio Addict

tambourine guy said:


> Looks like there is a new opamp in town.




  
 I have the Lycan on order with the new v5.  They did share a link to a non published page on the v5 I thought I would make it available.
  
 http://www.ssaudio.com.au/products/supreme-sound-opamp-v5/
  
 I bought 4 of an earlier generation for my RSA Apache but never got them to fit right.  I plan to try them with the Lycan.  I also have some extra RSA AD797 to try so this should be interesting.


----------



## imran27

I just thought of doing some study on why OPA1641/2 hasl/reported to have such a great soundstage, I probably found something relevant from the datasheet. The gain and phase vs frequency plot shows that the phase is almost flat for up to 1 MHz compared to OPA1612 which is inversely proportional to frequency up to 1 kHz and then constant up to 1 MHz.

This is making OPA164x more and more favorable.


----------



## imran27

I reviewed the datasheets of AD opamps and they also have this flat phase response.
  
 I want some user opinions on LM4562 vs OPA1642 especially in terms of details and soundstage.


----------



## Mad Max

1642 can be pretty holographic-sounding as far as soundstage and quite detailed, I have found.  4562 can dig up a bit more detail, but soundstaging isn't anything special.


----------



## imran27

imran27 said:


> The headphone OUT is actually a single low voltage supply Cmoy with a 1000uF cap coupling capacitor on the output.
> 
> Any comments on the OPA2365?


 

 I accidently destroyed the Vss pin of AD8397 so I had to replace it with the OPA2365.
  
 First impressions are: Much more detailed sound, more clarity and balance. Bass is more forward, treble feels a little fatiguing at times, but these are first impressions. Soundstage as expected is more intimate compared to the AD8397. Bit I am liking the details it can extract and the clarity, it is a very good sounding opamp compared to AD8397.


----------



## pelopidas

Have you measured the offset from the output of the opamp to ground? The reason I ask is that if the offset is under 20mv, you should consider removing the output capacitors. That will have a positive effect on soundstage and detail resolution. (Even more than input capacitors which are usually film and not electrolytic) Remember, audio is AC meaning the voltage swings in both directions. Electrolytics allow in one direction and block in the other.


----------



## imran27

1.215V, too bad. Anyways, I have 2000uF for the output, I think that's a pretty high value.


----------



## pelopidas

Wow. There is something wrong with the circuit design. Can you upload some clear pictures (front and back) so we can see the resistor values etc?


----------



## Tambourine Guy

How about those discrete type opamps? How do they generally stack again the ones from TI or AD opamps?


----------



## Mad Max

The ones that audio-gd used to make are alright, they kill older opamps in sound and OPA209 after you replace their crappy MKT decoupling PSU caps with anything better, but aren't as high-fidelity as chips like ADA4627, TL5580, ADA4610, OPA1652, or OPA827 and more.
 I still have the Sun opamp, very fun-sounding little thing.
 Edit:


----------



## leeperry

and they need a lot of juice anyway, ±18V to sound their best IIRC. OPA827 needs ±4V.


----------



## imran27

mad max said:


> The ones that audio-gd used to make are alright, they kill older opamps in sound and OPA209 after you replace their crappy MKT decoupling PSU caps with anything better, but aren't as high-fidelity as chips like ADA4627, TL5580, ADA4610, OPA1652, or OPA827 and more.
> I still have the Sun opamp, very fun-sounding little thing.
> Edit:



Did you just mention OPA1652? How are they? They are fairly new btw


----------



## Tambourine Guy

mad max said:


> The ones that audio-gd used to make are alright, they kill older opamps in sound and OPA209 after you replace their crappy MKT decoupling PSU caps with anything better, but aren't as high-fidelity as chips like ADA4627, TL5580, ADA4610, OPA1652, or OPA827 and more.
> I still have the Sun opamp, very fun-sounding little thing.
> Edit:


 

 Do these discrete type opamps share any common sound characteristics? Is it like tube vs solid-state where they have a sound that is instantly identifiable as being a discrete type... if that makes sense.


----------



## Mad Max

imran27 said:


> Did you just mention OPA1652? How are they? They are fairly new btw


 
  
 It's an awesome chip to use if you don't need strong output current drive.  Very "blind-roll" friendly, every opamp roller should try it at some point.
 Or if you are looking to replace a bipolar opamp in a circuit, OPA1662 is just as good, though I still like 4898 better.
  
 The one I'm really taken with lately is ADA4610-2B.  It is not finicky, has very low output impedance, and output current drive is better than 4556 and most of the opamps discussed in this thread.  It is uber-hi-fi like OPA827, ADA4627, LME49860, and LME49990.  Comes in MSOP as well, so it rocks as a big upgrade from 4580, 5534, and 4556 in a lot of situations, even mic preamps.
  
  
  


tambourine guy said:


> Do these discrete type opamps share any common sound characteristics? Is it like tube vs solid-state where they have a sound that is instantly identifiable as being a discrete type... if that makes sense.


 
  
 Not really if I recall correctly, but once you get a couple and get used to their particular sound, then you'll learn to identify them.  The Sun and Moon opamps are instantly identifiable, however, as they each do boast a unique sound.


----------



## SpudHarris

I have ADA4610-2B's here so curious... Although I haven't been tempted by anything since using Signetics 5534's (OBCA).


----------



## Mad Max

Digikey tells me LME49990 is being discontinued.
  
 Edit: The new OPA1688 looks interesting.  So it achieves lower distortion with higher-impedance headphones + louder volume?


----------



## pelopidas

That is terrible news! You just made me go buy some more 49990s just to have some reserves 
 I hate panic buying ....
 Also, don't buy them off of ebay, the majority of pics look like fakes. The surface is rough, like it was sanded, the print looks different too. They are cheap enough on Mouser and Digikey that you should not risk it on ebay.
  
 Here you can see the dimple on pin 1. this is how every single 49990 looked that i have ever used.

  
 here is what is flooding ebay. It is ground down and there is no dimple. The type looks wrong and the "squiggle" looks wrong


----------



## Mad Max

Perhaps, perhaps not.  Maybe something even better is in the makings to replace it in TI/National's lineup?


----------



## Foxer

Hey everyone!
  
 I want to replace the (1x) NJM2114 and the (3x) NJM2068 on my _CREATIVE X-Fi Elite Pro_ sound card.
  
 -- I'm looking for a good clean accurate and precise sound (but not boringly flat) --
  
 I have in mind the *OPA1602AID* as i heard very good things about it ..but i also read that *AD8599*ARZ is a pretty good candidate!
  
  
 Around here somewhere there was a post from @majkel, having a top 5 list:
 1. LT1028ACN8 *mono*
 2. OPA211ID (issues like in the review) *mono*
 3. AD797BRZ (finally I found slight imaging issues and timbral imbalance) *mono*
 4. LME49720MA *stereo */ LME49710NA (I guess I like the former a bit more) *mono*
 5. OPA-Sun v.2 (thick, flawless, likeable sound) *stereo*
  
 but as you can see, most of these are mono.. and i need stereo. And i don't know how they fair against the opa1602aid & ad8599
  
 Can you guys please help me out with some opinions/suggestions??
 Any advice is appreciated!
 Thanks!
  
 P.S. This sound card delivers +/-12V to the opamps.
  
  
 (_later edit_)
 I would be willing to try 2 mono LT1028ACN8 with an adapter, if they're THAT good.. although it would cost me an arm & a leg. 
 But still, i don't know how they fair against the (waaaaay more cheaper) OPA1602AID.


----------



## Mad Max

1602 and 8599 are good choices.  I would take OPA1662 or ADA4898-2 over 1602.
 I recommend ADA4610-2 as well.
 TL5580 is also worth a mention, and OPA2209 is no slouch either.
 4562/49720*MA* (the -NA version is DIP8 and you need the SOIC8 version) is common among the soundcard modders if I'm not mistaken.
 OPA Sun v2 must be sourced second-hand, unless Kingwa only makes them on-demand lately.  I have one (not for sale), it has a very fun and energetic sound.
 797 is serious business, and finicky (it tends to overheat/malfunction when thrown into a circuit that's not specifically designed for it).
  
 Whatever you end up using, be sure to add a WIMA cap across the power pins (pins 4 & 8 on duals, pins 4 & 7 on mono/singles)


----------



## Foxer

@Mad Max
  
 Thanks for the imput!
  
 Yes, the LM4562 was a popular swap for the X-Fi, but after a while ppl ditched it for better alternatives. The LM4562 was said to be very dynamic/impressive, but not very accurate, and kind of metallic sounding (at least on the x-fi)... plus, very susceptible to EMI.. and LM49720(ma) would be just a better variant of it.. or so i read.
  
 Can you somewhat describe the sound or share some impressions on the OPA1662 & ADA4898-2 in relation to the OPA1602AID ? 
 I'm planing to order everything from Farnell, and the ADA4894-2*YRDZ** *is the only "ADA4898-2" variant they have (any good?), and sadly no OPA1662's  ..so it might be a bit of a hassle to try and find it.
  
 Also, is the Wima cap you linked, the exact value i should use?? (250V seems a bit excessive). Coz i was also planning to use a Film PolyPropylene CAP on the OpAmps, of 0.1uF 63V.. (wima's lowest voltage for 0.1uF caps is 100V sadly; and 250V for 0.15uF)
  
 (_later edit_)
_Both the 1602 and 8599 were tried on the X-Fi by different ppl, with reported amazing results. Thing is.. not one person tried both 
	

	
	
		
		

		
			





 .. so i have no actual comparison btwn them._
_Also, i don't know if i should venture off the "proven path", as i have read that an OpAmp could sound different depending on what you put it in, and the surrounding circuit.. don't know how much though.. _


----------



## Mad Max

The higher the voltage, the better the dielectric, or so another guy told me.  To me, it does sound a bit better for the cap to be higher in voltage rating.  I go for the 100V or 63V WIMAs when there's not enough physical space for the ones I linked.  Those smaller voltage caps tend to fit into tight spaces, if not, then 100V 0.1uF WIMA MKS4 is nearly as good and uber compact (only 2.5mm thick).
  
 I like 1602, but feel that 4898 and 1662 offer a more refined sound, especially 4898.  Who knows, perhaps 1602 will be "happier" in the Creative card than 1662 and give you better sound than 1662 might?  That 4898 version you linked is the right one.  4898 has this naturalness to its sound that just rocks, plus it is quite hi-fi.  Pretty neutral, too, so long as you give it the extra cap as I recommended.  There's no other place for you to source it from?
  
 I cannot tell 4562 and 49720 apart, and they're supposed to be the same chip anyway, like OPA1642 vs. OPA2141.  I like LME49860 and 49990 better than 4562/49720, as far as those National Semi chips.


----------



## Foxer

I live in Romania.. so it can be a bit difficult to source electronics that aren't that "mainstream", at a decent price. Farnell delivers here from their stock in the UK and take @ 6$ for shipping .. Mouser delivers from the US and takes @ 32$ for shipping 
	

	
	
		
		

		
		
	


	




 
 But i will put a ADA4894-2YRDZ on my list 
	

	
	
		
		

		
		
	


	




 I'm thinking of getting one of each & testing them out before ordering 3 more for the surround channels. 
  
 Just hope my soldering skills will be up to par.. (argh, i wish Farnell also had some adapters! ..but i'm gonna take the ghetto route & just solder on some wires for testing 
	

	
	
		
		

		
		
	


	




 ..and not gonna forget the cap 
	

	
	
		
		

		
		
	


	




 )


----------



## pelopidas

I have found that putting a 10uf Silmic II on the power pins makes a more profound improvement than a 0.1 film. The board will already be bypassed with various capacitors to keep the opamp stable but the power might be filtered with "average" capacitors in the first place. Putting a quality capacitor on the chip in essence cradles the opamp in its sonic signature vs the signature of the other capapcitors. If you want really deep and full bass put a 10 uf Silmic II on the chip. It's better than any other capacitor I have tried.


----------



## Foxer

pelopidas said:


> I have found that putting a 10uf Silmic II on the power pins makes a more profound improvement than a 0.1 film. The board will already be bypassed with various capacitors to keep the opamp stable but the power might be filtered with "average" capacitors in the first place. Putting a quality capacitor on the chip in essence cradles the opamp in its sonic signature vs the signature of the other capapcitors. If you want really deep and full bass put a 10 uf Silmic II on the chip. It's better than any other capacitor I have tried.


 
  
 I was actually thinking of changing the card's power rail decoupling caps for the OpAmps. They are 2x G-Luxon of 220uF 25V , and i was wanting to replace them with low ESR Panasonic FM's of the same values. (Farnell doesn't have any ELNA (silmic) caps 
	

	
	
		
		

		
		
	


	




 ).
 Some people replaced those caps with even bigger ones, but i don't know... maybe i should too? I know different values caps charge/discharge at different rates.. so a bigger cap would take more time to charge, and suck up more Amps.. 
  
 Also, the 10uF cap u recommend; i'm thinking 16v..? (the opamps are fed 12V)
  
 I'm really actually thinking of trying both a 10uF Panasonic FM, and a 0.1 WIMA PP Film in parallel.. would that be bad in any way?
  
 This card IS actually severely lacking mid-low bass..


----------



## Mad Max

I feel that FMs contribute to a particularly ugly and fatiguing sound.  FCs are okay, but add some midrange dryness.
 From impressions I've read around the web, Rubycon ZLS, ZLG, ZLH, and RX30 may be some good stuff, I haven't gotten around to trying them out yet.
 I hate the massive size of Silmics.


----------



## Foxer

Damn it... now i have to scrap half of my check-out list on Farnell ) .. I was about to order @ 20 FMs.
 TBH i did come across recommendations for FCs (if ELNAs couldn't be sourced) but not for FMs. I just went for the FMs coz of their lower ESR.. and thought they would be better.
  
 Looks like Farnell has Rubycon ZLG & ZLH.. I'm gonna do a little research.
  
  
 (it pisses me off how hard are ELNAs to find ...impossible actually in RO.  Things would have been so easy if i could have just popped to the store and bought some 
	

	
	
		
		

		
		
	


	




)


----------



## pelopidas

http://m.ebay.de/itm/12-pcs-10uF-25V-ELNA-RFS-SILMIC-II-AUDIO-Capacitor-85-C-br-NEU-Kondensator-/361425093253?nav=SEARCH

That should do it for the opamps. What value do you need for the board?


----------



## Foxer

pelopidas said:


> http://m.ebay.de/itm/12-pcs-10uF-25V-ELNA-RFS-SILMIC-II-AUDIO-Capacitor-85-C-br-NEU-Kondensator-/361425093253?nav=SEARCH
> 
> That should do it for the opamps. What value do you need for the board?


 
  
 Thanks @pelopidas, but i was kinda trying to stay away from eBay, and also get everything from one place (for convenience sake) but also to avoid extra shipping bills.. coz i can barely afford the order as it is. 
 My entire order on Farnell was about 40eur incl. shipping. If i order from eBay, shipping would cost at least an additional 10 euros... which tbh i'd rather spend on some extra opamps or caps -for testing 
	

	
	
		
		

		
		
	


	



  
 As soon as i get the chance, i'll do the research on the Rubycon ZLG & ZLH, cross my fingers and hope that ppl found them to be good ELNA replacements..
 (Got some furniture coming in tomorrow, so i need to take care of that 4 the moment..)


----------



## pelopidas

Farnell does carry the Panasonic SEPF line. Much much better than FM. Almost as good as Silmic. Just make sure you don't exceed the rated voltage.


----------



## Foxer

pelopidas said:


> Farnell does carry the Panasonic SEPF line. Much much better than FM. Almost as good as Silmic. Just make sure you don't exceed the rated voltage.


 
  
 Aren't Polymer caps bad for audio?
  
@trodas did some explaining here: 
http://www.techpowerup.com/forums/threads/x-fi-sound-bugs-i-think-i-have-a-solution.23582/page-3#post-887544
  
"_Polymer caps is great for high-frequency voltage filtering (just check their frequency response curves, for christ sake!) while using them for anything getting close to audio is UNFORGIVABLE mistake that completely erase any filtering in low-frequency, hence the strong bass line kill the quality effectively._
_You can't measure that on the RMAA, to show this problem you need the DAC/opamps output a loud bass line and then the polymers crumble and kill the voltage filtering = the card output get much less that satisfactory.

Just because todays there are some kind of "hype" about polymers does not mean that they are usefull for everything. They have a very strict usability around 200 - 500kHz, and that it is.

The key to understand this problem is thing called ripple rating coeficient. It basicaly says what multiplier has to be applied on the rated ripple for different frequencies. Nothing show this better that this table:

Samxon X-con URL polymers: *120Hz = 0.05*; 1kHz = 0.30; 10kHz = 0.70; 100kHz = 1.00
Samxon elyctrolyte GA caps: *120Hz = 0.50*; 1kHz = 0.80; 10kHz = 0.90; 100kHz = 1.00_

_The specs are very much the same as with all other polymers - even spoken - the better polymers, the worser they run at low audio frequency._"


----------



## trooper05

"Whatever you end up using, be sure to add a WIMA cap across the power pins (pins 4 & 8 on duals, pins 4 & 7 on mono/singles)"
  
 Will this provide any benefit on a Asus STX? 
  
 I currently run LME49990 super analytical OPAMP, I am after some OPA627's (Apprently sound more relaxed, laid back) but they are way too expensive and too many fakes around. Can anyone recommend something similar? Would OPA827 be a good choice?
  
 Any advice would be appreciated!


----------



## pelopidas

Just as there is a wild difference in electrolytic capacitor quality for audio so too do "oscon" type capacitors have variations in quality. 
From what you were talking about, I am unsure if the capacitor is being used as an output capacitor or if it is being used as a psu cap. If you are talking about an output capacitor then I might agree with you that it should be avoided at all costs, but I would also avoid electrolytics at all costs too. If in a psu position it is hard to imagine that a polymer capacitor cannot supply electrons to a circuit. 
From my empirical observations the Panasonic SEPF is a step down from Elna Silmic in any psu application. But it is much much better than a Panasonic FM for instance. It is a very correct sounding capacitor. Every little detail comes through cleanly and without harshness. All the bass comes out tightly without any muddy flabbiness. It's all there as it should be. It is incredibly fast. If you like fast electronic and want to hear every millisecond, every shiver of a cymbal, then try a SEPF. I actually use silmics bypassed with a lower value SEPF in my headphone amp. But don't take my word for it. Spend 2 dollars and try it your self.


----------



## pelopidas

To trooper
Try a wima so you know the sound, but then try a 10 uf Silmic on your 49990. I use the 49990 in my xonar bypassed with a Silmic and it might be what you are looking for. You keep the detail of the 49990 but add warmth and space.

The way capacitors are used close to the opamps is for stability. If you look at the product sheet you will generally see 10uf or 4.7uf and 0.1uf going from + to ground and from - to ground. This stabilizes the rails by removing any jitters and sending them to ground. However, the operation of the opamp is powered by the + and - and not by ground. While a 0.1 across the + and - is oftentimes used to calm an unstable opamp down (compensation would be much more effective) it is way to small to improve the sound. You will notice it if the capacitor you choose is sibilant. You will hear it in the treble, but 0.1 is not enough for the entire audible spectrum. When adding a capacitor to + and - you are in essence adding a power reserve to the opamp directly. In this position you will "hear" the capacitor. So it needs to be big enough to supply the whole dynamic range (think bass drum kicks which move the speakers in your headphones more than any treble sounds).

The immediate reaction to this might be "you don't want to hear a capacitor!" Well, there is no way around it. In your STX, your power comes from the computers PSU. Lots of "sufficient" capacitors there for powering your computer but all of them awful for audio. From there it goes to the STX which will have some filtering using more capacitors to clean up the noisy power of the computers PSU. From there it goes to your opamps that are bypassed to ground for stability using ceramic (yuk) and film and you also have some electrolytics there (nichicon fine gold?) for power reserve. All of these capacitors have an effect on your sound. This is why you need to choose the very best sounding capacitor to be the very last one in the chain. 
For me it is ELNA Silmic on my xonar. it goes to my headphone amp which is a mixture of Silmic and SEPF and then finally on the opamps in my headphone amp I have ELNA Cerafine because they have a beautiful clarity that complements the full and rich Silmics. 

So the fact is, you will be listening to capacitors so you have to choose which ones sound best to you.


----------



## trooper05

Thanks for the info @pelopidas How do you bypass on them small LME49990, you put in between pins 4 & 7 on both OPAMPS? Or is there a better way to do it?


----------



## pelopidas

I am assuming you have your 49990's on a dual adapter. In this case just go from + to - so pin 4 to 8. That will take care of both. If they are single soic then 4 to 7. 
But you have a STX don't you? So you have sockets for dual opamps. Try it like the pic I attached. That's what I use in my xonar


----------



## trooper05

@pelopidas
 Thanks for the info, I understand what you mean now, the capacitor is there to store a small amount of energy to ensure stability of the OPAMP. I am going to  try it on my LME49990 
	

	
	
		
		

		
			





, I didn't see the picture yesterday on your post seems simple to install. I guess my only concern is fitting the EMI shield back on 
	

	
	
		
		

		
		
	


	




.


----------



## pelopidas

I look forward to your impressions. Leave the emi shield of for a while so you can play around with different capacitors.
 You can read about my experience a few pages ago.
 www.head-fi.org/t/432749/the-opamp-thread/4905#post_11796572
  
 As a side note, I started this by being dissatisfied with the bass on the AD797. 10uf Silmic totally changed that opamp, put some meat on the bone so to say.
 As a side note, ( i guess the other side) is once you do this to the AD797 and LME49990 other opamps such as the 49720, 49710, 2107, 5534, 827 and even the LT1028 prove to be really inferior. My no.1 is 49990 with silmic and next is 797 with silmic. The 49990 is more spacious, noticeably better noise rejection and has an ease about it while being super detailed.
  
 Can anyone recommend anything that tops those? Are the muses really worth all that extra money?


----------



## trooper05

@pepopidas
  
 I just read your experience from a few pages ago, it seems you have experimented with various OPAMPS and capacitors 
	

	
	
		
		

		
		
	


	




. I have *10uF 25V ELNA **on the way, *I will post impressions once I have installed them (cant wait). 
  
 I have only experience with 49720, 49710 and 49990, and stock OPAMP on STX. If you do find anything better than the LME49990 let me know! The only OPAMPS I hear that are better are discrete and are super expensive.


----------



## pelopidas

I look forward to your impressions too. Don't just do the silmics, if you have any film, silver mica or anyother capacitors sitting around right now you can try it out. This way you can get a feel for what they sound like. Then of course, let us all know what you found out!


----------



## trooper05

I bypassed the LME49990 with 10uF 25V ELNA today. I am actually speechless on how much the sound has improved, there is more separation, detail and control in the lower frequency's. The background is black, the sound has become dark. Everything you stated in your earlier posts (www.head-fi.org/t/432749/the-opamp-thread/4905#post_11796572) was accurate. The sound is more relaxed exactly what I wanted.  I honestly did not expect so much improvement from this cheap mod 
	

	
	
		
		

		
		
	


	




  
  
 I even de soldered  and re soldered them to double check it was not my imagination
  
 Next thing to try is a wima cap, I think I will stick with this for a few hundred hours first let them caps burn in, not even past the four hour mark yet 
	

	
	
		
		

		
		
	


	




.
  
 The LME49990 also runs way cooler, anyone who is having trouble with hot OPAMPS should do this mod!
  
 Thank you @pelopidas for the information!


----------



## pelopidas

It really is interesting how much the 49990 benefits from this. The 797 also really is transformed but other chips not so much. I tried the 49720ha with the Silmic and a whole bunch of other capacitors but all that happened is that it removes a certain haze that only illustrates that opamps short comings. I think it is, like you said, the very black background that really exposes the true capability and sound of the opamps. The silmics, more than other capacitors, really lock the sounds solidly in the sound stage. That clarity is what I miss most when rolling non-Silmic-bypassed opamps now.


----------



## SpudHarris

Got a few caps on route for testing but have some Muse 33uF here. Which lead goes to pin 4, the long or short?

Sorry if I sound like a bimbo


----------



## trooper05

Here is the pinout for both a dual or single OPAMP:
                            *DUAL*                                                  *SINGLE*

               
  
 The longer leg is normally the positive, so the shorter leg will go to pin 4. Unless of course you have a bipolar capacitor then it wont matter.


----------



## ScottFW

Nichicon Muse caps are bipolar if memory serves. Newer ones have "BP" marked on them. For the electrolytics where polarity matters, I find it easier to rely on the stripe that identifies the negative lead.


----------



## SpudHarris

Thanks both for the replies  

These are what I am hoping to use. I've had them for ages as I used to make LODs for my imod.


----------



## Mad Max

Those are the ES bipolar electrolytics.  I found them muted-sounding when I rolled caps in my ol' Creative soundcard long ago.  Whether on outputs or power supplies, I don't like them one bit.


----------



## SpudHarris

Trying these as all my other caps are 16v only. These are 470uf Nichicon 25v...

Got 35v Simlic ll on order.


----------



## Audio Addict

spudharris said:


> Trying these as all my other caps are 16v only. These are 470uf Nichicon 25v...
> 
> Got 35v Simlic ll on order.




Nice amp for rolling. 

I am using 4 AD797 in my RSA Apache. I have no soldering skills, any recommendations to take it to another level?


----------



## SpudHarris

audio addict said:


> Nice amp for rolling.
> 
> I am using 4 AD797 in my RSA Apache. I have no soldering skills, any recommendations to take it to another level?




Yes it's a great amp period. I am using it with a Graham Slee PSU1....

I personally love the AD797 but my favourites are:

AD744 OBCA
NE5532 (Signetics) OBCA
LME49990
Muses 01

The V5 Burson is an astounding unit but limited by its size.


----------



## Audio Addict

How did adding the capacitors improve the AD797? I would to try it but no DIY skills here.


----------



## Mad Max

Generally, everything about the sound improves to some extent.


----------



## trooper05

I still cannot believe how much the sound has changed with the *10uF Silmic *bypass, that dark black sound cant get enough of it. 






 I did a bit of research looking at datasheets of various OPAMP's, it seems implementation varies depending on which OPAMP used:
  
 The AD797 within the datasheet states:
 "_A 1.0 μF to 4.7 μF tantalum in parallel with 0.1 μF
 ceramic bypass capacitors are sufficient in most applications.
 When driving heavy loads, a larger demand is placed on the
 supply bypassing. In this case, selective use of larger values of tantalum capacitors and damping of their lead inductance with
 small-value (1.1 Ω to 4.7 Ω) carbon resistors can achieve an
 improvement_" Pg 13
  
 The LME49990 states within its datasheet:
 "_SUPPLY BYPASSING
 To achieve a low noise and high-speed audio performance, power supply bypassing is extremely important.
 Applying multiple bypass capacitors is highly recommended. From experiment results, a 10μF tantalum, 2.2μF
 ceramic, and a 0.47μF ceramic work well. All bypass capacitors leads should be very short. The ground leads of
 capacitors should also be separated to reduce the inductance to ground. To obtain the best result, a large
 ground plane layout technique is recommended and it was applied in the LME49990 evaluation board_." Pg10
  
 It seems as each OPAMP has specific bypass requirements in order to function within its specified optimum values. When the circuit does not have the specific requirements detrimental performance can be expected such as oscillation with associated overheating along with a potential veiled sound which is impossible to notice without a oscilloscope. The information within the datasheets seem a little vague on what is the best bypass arrangement is. 
  
@SpudHarris
  Post us your impressions on the Simlic ll capacitors  I look forward to hearing your impressions!


----------



## zilch0md

Spoiler: A summary of the recent cap discussions






pelopidas said:


> I have found that putting a 10uf Silmic II on the power pins makes a more profound improvement than a 0.1 film. The board will already be bypassed with various capacitors to keep the opamp stable but the power might be filtered with "average" capacitors in the first place. Putting a quality capacitor on the chip in essence cradles the opamp in its sonic signature vs the signature of the other capapcitors. If you want really deep and full bass put a 10 uf Silmic II on the chip. It's better than any other capacitor I have tried.


 
  
  


pelopidas said:


> http://m.ebay.de/itm/12-pcs-10uF-25V-ELNA-RFS-SILMIC-II-AUDIO-Capacitor-85-C-br-NEU-Kondensator-/361425093253?nav=SEARCH
> 
> That should do it for the opamps. What value do you need for the board?


 
  
  


foxer said:


> Aren't Polymer caps bad for audio?
> 
> @trodas did some explaining here:
> http://www.techpowerup.com/forums/threads/x-fi-sound-bugs-i-think-i-have-a-solution.23582/page-3#post-887544
> ...


 
  
  


trooper05 said:


> "Whatever you end up using, be sure to add a WIMA cap across the power pins (pins 4 & 8 on duals, pins 4 & 7 on mono/singles)"
> 
> Will this provide any benefit on a Asus STX?
> 
> ...


 
  
  


pelopidas said:


> To trooper
> Try a wima so you know the sound, but then try a 10 uf Silmic on your 49990. I use the 49990 in my xonar bypassed with a Silmic and it might be what you are looking for. You keep the detail of the 49990 but add warmth and space.
> 
> The way capacitors are used close to the opamps is for stability. If you look at the product sheet you will generally see 10uf or 4.7uf and 0.1uf going from + to ground and from - to ground. This stabilizes the rails by removing any jitters and sending them to ground. However, the operation of the opamp is powered by the + and - and not by ground. While a 0.1 across the + and - is oftentimes used to calm an unstable opamp down (compensation would be much more effective) it is way to small to improve the sound. You will notice it if the capacitor you choose is sibilant. You will hear it in the treble, but 0.1 is not enough for the entire audible spectrum. When adding a capacitor to + and - you are in essence adding a power reserve to the opamp directly. In this position you will "hear" the capacitor. So it needs to be big enough to supply the whole dynamic range (think bass drum kicks which move the speakers in your headphones more than any treble sounds).
> ...


 
  
  


trooper05 said:


> Thanks for the info @pelopidas How do you bypass on them small LME49990, you put in between pins 4 & 7 on both OPAMPS? Or is there a better way to do it?


 
  
  


pelopidas said:


> I am assuming you have your 49990's on a dual adapter. In this case just go from + to - so pin 4 to 8. That will take care of both. If they are single soic then 4 to 7.
> But you have a STX don't you? So you have sockets for dual opamps. Try it like the pic I attached. That's what I use in my xonar


 
  
  


pelopidas said:


> I look forward to your impressions. Leave the emi shield of for a while so you can play around with different capacitors.
> You can read about my experience a few pages ago.
> www.head-fi.org/t/432749/the-opamp-thread/4905#post_11796572
> 
> ...


 
  
  


pelopidas said:


> I've tried all popular opamps in my Xonar in the last 4 years. I kept coming back to AD797 in I/V and 49720HA in buffer.
> Thats a pretty decent sound but it wasn't right. The desire to keep messing with it, straining to listen deeper into the recording leads to trying all kinds of opamp variations.
> "its too sibillant.. the bass is flabby... where is the bass?..the soundstage is small or muddy..."
> Well, after playing around for 4 years, the solution is stupidly simple.
> ...


 
  
  


pelopidas said:


> the Xonar HDAV 1.3
> Probably the least of all Xonars right out of the box. After bypassing the output caps with wire, it opened up completely into something quite lovely. But, obviously, it wasn't good enough because I have been modding and swapping opamps from the beginning.
> Only two mods sofar have had an appreciable effect.
> 1. bypassing output capacitors with wire.
> ...


 
  
  


pelopidas said:


> Burn in for capacitors? Absolutely.
> Burn in for Opamps... Well, I know that some think you need to. I personally don't know that I have ever heard a difference. I have listened for it but a new lme49720ha sounds the same as one I have used for years.
> If you can hear the difference and want to burn it in, then open foobar or some similar player and put a track on repeat. Chose something that has deep bass and lots of treble. Let that play over night.
> On my xonar, when im burning in capacitors on the opamps like i am right now, i turn off my headphone amp and turn the volume to 100. Let it do its thing for a while, come back, don't forget to turn the volume down and test with a familiar song.


 
  
  


trooper05 said:


> I bypassed the LME49990 with 10uF 25V ELNA today. I am actually speechless on how much the sound has improved, there is more separation, detail and control in the lower frequency's. The background is black, the sound has become dark. Everything you stated in your earlier posts (www.head-fi.org/t/432749/the-opamp-thread/4905#post_11796572) was accurate. The sound is more relaxed exactly what I wanted.  I honestly did not expect so much improvement from this cheap mod
> 
> 
> 
> ...


 
  
  


trooper05 said:


> @pepopidas
> 
> I just read your experience from a few pages ago, it seems you have experimented with various OPAMPS and capacitors
> 
> ...


 
  
  


trooper05 said:


> Here is the pinout for both a dual or single OPAMP:
> *DUAL*                                                  *SINGLE*
> 
> 
> ...


 
  
  


trooper05 said:


> I still cannot believe how much the sound has changed with the *10uF Silmic *bypass, that dark black sound cant get enough of it.
> 
> 
> 
> ...


 
  


  
 You guys are going to make me learn to use my soldering iron.  It's late, here, but I'll probably be back with some questions, later.


----------



## pelopidas

I ordered some small 10uf caps in the following flavours.
 Nichicon Muse BP - the bipolars. I am really quite curious to see what a bipolar sounds like.
 Panasonic FC - the "go to" when building an amp for a friend of a friend who does not know better.
 Nichicon Muse KZ - really quite decent caps from previous experiences.
 Once these arrive, I am going to retest all caps and opamps again
 These were my previous experiments but this needs to be better organized.

 http://www.head-fi.org/t/432749/the-opamp-thread/4905#post_11796572
 http://www.head-fi.org/t/432749/the-opamp-thread/4920#post_11804552
  
 since so many of us have very different equipment, it would also be interesting if you guys would try some of these and let us know how it responds to your equipment.
 Since I primarily listen through my HD650 it is very well possible that I am tuning the sound to be excellent for this scenario. What do you guys listen to and what are your impressions of any mods you make?


----------



## Stadtpirat

Hi,
 Thank u for the great MOD!
 i want use the DUAL 49990 in the O2 and ZXR.
 What i need for DUAL 49990 SILMIC Mod and what are the numbers of the pins for solder?
  
 I have the DUAL 49990 on DIP8.
  
 In germany i can buy:
 WIMA MKS4 63V 10uF 10% tol.
  
 How Many V are good?
 What is better WIMA or SILMIC?


----------



## SpudHarris

I am using the Lycan from Burson. Man, this thing is the OpAmp rollers dream... It's a test bed. Reasonablely priced but transparent as they come, powerful and easily changeable OpAmps.

Listening to an old favourite tonight from my Graham Slee Solo days, the AD823. Using the GS PSU1 with the Lycan which has to help. When my Silmic II's get here I will be trying them on AD797 / ADA4627 (current favourite with the Lycan) OPA111BM and LME49990.


----------



## pelopidas

Hey Spud
How does the Lycan compare to the Fi-quest you were using last time you were talking Amps? Have you tried the output bypassed 5532 on there? I looked it up on Bursons website and it looks like they are using silmics on the board already. Are the 4 big caps silmics?


----------



## SpudHarris

Hi pelopidas,
I haven't compared them like for like but can tell you that the Lycan is a more powerful amp, and from memory it is more transparent than the Fi-Q. That said, the Fi-Q is more flexible and of course portable. I have had the AD823 in place for a couple of days and could quite happily keep it where it is... I have never heard vocals so intimate and clean.

The output bypassed Signetic 5532 is amazing and I will take the AD823 out tonight to test.

The Lycan is an amazing amp, even more so when you consider the cost.


----------



## zilch0md

pelopidas said:


> I ordered some small 10uf caps in the following flavours.
> Nichicon Muse BP - the bipolars. I am really quite curious to see what a bipolar sounds like.
> Panasonic FC - the "go to" when building an amp for a friend of a friend who does not know better.
> Nichicon Muse KZ - really quite decent caps from previous experiences.
> ...




I would love to participate in the experimentation here, but given that my soldering skills are deplorable, I will just keep following this thread and see which caps you guys end up using on the LME49990. I realize you might never settle on a "final" solution, as I thought you were "there" with the Silica II bypassed with teflon:



Your description of that mod was mouthwatering, but it seems you're after something better still, so I will remain patiently dependent on your diligent research. 

I really appreciate your passion and energy!

Mike

PS> A quick shout to Nigel - How's it going?


----------



## SpudHarris

Hey Mike, I'm good pal thanks...

I'm still awaiting my Simlic II's :rolleyes: I'll definitely report back ones I have tried them on the 49990's. If you want me to solder one up for you with caps just shout me, I'm quite nifty with my soldering iron  I have a few dual modules lying around.

The nice thing about the Lycan is that rolling is soooooo simple and even those modules in your post above will fit...


----------



## pelopidas

Hey Mike,
 well I seem to be in the middle of messing around with this again. I do love the teflons on there but look at how ridiculously huge they are 
	

	
	
		
		

		
			





. I actually had to support them with electrical tape on my sound card so they didn't accidentally fall out. Size aside, I am going to test those out again, along with some other new additions..
  
 Hey Spud,
 I am really curious if you will hear much of a difference on the Lycan if you bypass the opamps with silmics. Silmics are what are already being used for the power supply as far as I can tell on the lycan. When your caps come, can you also test the opamps in your Fiquest to see if it behaves similarly or differently?


----------



## SpudHarris

pelopidas said:


> Hey Mike,
> well I seem to be in the middle of messing around with this again. I do love the teflons on there but look at how ridiculously huge they are :eek: . I actually had to support them with electrical tape on my sound card so they didn't accidentally fall out. Size aside, I am going to test those out again, along with some other new additions..
> 
> Hey Spud,
> I am really curious if you will hear much of a difference on the Lycan if you bypass the opamps with silmics. Silmics are what are already being used for the power supply as far as I can tell on the lycan. When your caps come, can you also test the opamps in your Fiquest to see if it behaves similarly or differently?




Understood and I definitely will test both and report back, well if the Simlics ever get here :rolleyes:


----------



## pelopidas

Did you get the Burson opamp with the Lycan?


----------



## SpudHarris

I did, yes. It is amazing in every way but will have limitations due to its form factor....

Anyway enough of that for now! Santa came today, woohoo...




Firstly my Simlic II's came today so I wasted no time soldering them up. Listening with 49990 at the moment but have a dual AD797BRZ Module and 2 X ADA4627's waiting in the wings. Too early to evaluate as I literally only just finished brushing the flux off 

I must find a way to fit the Burson V5 into my Fi-Q. Maybe make a DIP socket with extension wires and lay the V5 where the battery usually sits for home/transportable/vacation use at least.


----------



## zilch0md

spudharris said:


> Hey Mike, I'm good pal thanks...
> 
> I'm still awaiting my Simlic II's
> 
> ...


 
  
 That's very generous of you, thanks!   When I make up my mind what I want exactly, I'll order the parts and send them to you.  Until then, I'll be following the action here, to see what you guys come up with.
  
 Thanks!
  
 Mike


----------



## zilch0md

pelopidas said:


> Hey Mike,
> well I seem to be in the middle of messing around with this again. I do love the teflons on there but look at how ridiculously huge they are
> 
> 
> ...


 
  
 I suppose I'd rather have the case of my PB2 closed, than leaving it open to accommodate huge caps, but I'm willing to put SQ first.


----------



## vegards

Hello pelopidas,
  
 Awesome work!
 Do you run 3x 49990 with the silmics on your card? Or is it some other combination on the buffers and I/V?

 I just recently did my first solder and want to try this mod. I'm running 3x49990s DIP8-adapter on my essence stx now. I guess I can just copy you technique and see how it goes  This are the correct capacitators: Elna Rfs silmic II 10uf 25V 10mfd audio Capacitor?


----------



## pelopidas

Hi vegards,
  
 I switch between 2x AD797BRZ in I/V and LME49999 in buffer and then back to LME49990 in all three positions. Both combinations are really good but have a different soundstage. Detail resolution is about the same on both but the feel is different. The majority of the time goes to the LME49990 though. I do have Silmic II 10uf on both I/V and buffer.
 As a side note, I have some Nichicon Muse KZ 10uf and Panasonic FC 10uf here now. Just waiting on the green Bipolars to arrive so I can begin the testing with those other caps. I also have Cerafines and Panasonic SEPF sitting here. I will put them all head to head and see what I see.
 Don't let this put you off of just going with the Silmic though. I am not sure that these are completely neutral, but what they do is really really good.


----------



## Mad Max

I find FC relatively neutral, a bit dry, and rather thin in sound but at least bass is real nice out of it.  I love how treble comes out with KZs.


----------



## Audio Addict

http://www.head-fi.org/t/432749/the-opamp-thread/5040#post_12132253
  
 Since I have zero soldering skills, would anyone be interested in selling a quad AD797 or the LME49990?  I would love to compare give them a listen through my Apache and Lycan.


----------



## pelopidas

*Burson SS V5 Opamps*
  
 For those of us who are not electrical engineers who can build entire systems from scratch, but love music and love playing around with our gear, we are basically limited to opamp rolling.
 Here are a list of opamps I have played with. The jellybean JRC 2114D that originally populated the Xonars. The opamp that first started the drive to find something better.
 Sure, the Xonar sounded better than any onboard audio but it wasn’t perfect. Something was missing. And so now we have threads with thousands of posts where we recommend this or poo-poo that. And so I bought some OPA2107, some 134’s, some LME 49720’s, some, NJM4556's, some 49860’s and then some 49720HA and some 49710HA and some 49713HA (for my headphone amp, not the Xonar) and some 827’s and some 627’s and some LT1363’s and some LT1028 and some LME49990 and even the 5534’s and of course the AD797 and many more that just went in for a short while to come out and be forgotten again.
 The process of elimination left me with the AD797BRZ and the LME49990 as the best  all-around opamps. However, they both sound anemic unless bypassed with a 10uf Silmic II which is, for me, now a standard practice with those two opamps. They have good detail retreival, good soundstage and no weird tonal issues such as sibilance or flabby bass. I figured, this was as good as it got with the equipment I have.
  
 Well, as Ronda Rousey learned, there is always something out there that just kicks more ass.
  
 After reading about discreet this and discreet that for too long without ever trying it, the time was ripe to see what discreet is all about.
  
*The unboxing*
  
  
  
 The Bursons are well packed in a custom protective case for safe transport and storage. 

  
 Makes you feel like you are holding something special. They are tall but don’t really have a much
 larger footprint than a regular browndog adapter.
 They both fit side by side on in a Xonar.


  
  
*How do they perform?*
  
 Out of the box, they are peaky and will quickly fatigue you. These, per the manufacturer’s recommendation, need a minimum of 100 hours of burn in. I hate waiting….
  
 Fast forward two and a half work-weeks of burn-in and it’s time to start listening and comparing.
  
 What you will notice first are the details. They are clear, they are everywhere.
 I attribute this virtue of the Bursons to their speed. They resolve everything – perfectly. To hear the shimmer on the cymbals in such exacting detail is fascinating. It sucks you into the music.
 At first it seems like work to listen so closely to micro details that you haven’t heard before but before you know it, you are just staring off into eternity swaying to the music.
  
 Take Kat Edmonson  “Just like Heaven” as the best cymbal example of this. The cymbals are left and right and the clarity that the Bursons provide give it a more pure, metallic and melodic presentation.
 Another Kat Edmonson example would be “I don’t Know”. I always thought this was a type of afterthought recording because the brush on the snare was just too “shhh” and low-fi sounding.
 That’s not what is going on.
 With the Bursons, you hear one of the musicians slightly coughing. I have never heard that before. You hear the creaking of a chair that someone is sitting on. You hear each strand of the brush as it is being pulled over the snare drum.
  
 Secondly, there is a sense of space. There is a 3D aspect that starts with the instruments. The 49990 soundstage is much like an oval. The 797 is more like a pyramid or trapezoid.
 It feels closer to the ear with straight walls and this is one of the reasons why I prefer the 49990 to it. Both those opamps have a soundstage that is big enough to place all instruments where they belong, like pictures on a wall.
 I suppose Bas Relief would be a better description. You hear the instruments coming from the wall, etched into the wall.

  
 This is where the Bursons really add something I have not experienced yet.
 There is no soundstage per se. There are no walls. The instruments are in the correct location but standing in space and you can hear not just the front of the music but the back too. I don’t know how to put this experience into words. We all know that artificial soundstage of the 49720 where things feel pulled apart wider than they should be. Well, the Bursons sound wide because there is nothing behind the instruments. No perceived limit. It’s like looking up at the stars in the desert on a clear night. If someone is standing 10 feet from you in a room with their back to the wall playing the guitar or standing 10 feet from you in the desert under the stars, the distance from the music to you is the same but what’s behind it is different. This is felt more in acoustic recordings than electronic.
  
 This also can bring the music much closer. Some opamps put the music in your head, these put you in the music.
 Listening to Kat Edmondson you expect to feel her breath as she sings to you. Seeing how I love Kat this is a great experience.  Sometimes this can be .. interesting.
  
 As you guys know from my previous posts, I have started adding 10uf capacitors to the opamps to try to mitigate any shortcomings they might have. I believe one of these shortcomings are in the capacitor choices that were made by manufacturers when they put the DAC, Soundcard, Headphone amp… whatever together. The power that is fed to the opamps is like the raw ingredients that go into cooking. Either you use the best and freshest you can find or you used frozen and canned. The cook is the opamp. No matter how good the chef, if the ingredients are not great, the result is not great. 
 So with the AD797 and LME 49990 I found that Elna Silmic II 10uf is what is needed to bring out the best. This gave it a black background, better dynamics and much better bass. I love good bass.
  
*Silmic on the Bursons?*
  
 I did not want to start soldering onto these beauties, especially since I need to put on and remove the caps multiple times to verify what I am hearing. So I just took a dip8 adapter and soldered the caps to these. This way I can have it on and off in just seconds.

  
 While the Silmics were a night and day difference, and all for the better with regular opamps, this is not cut and dry with the Bursons. The SS V5 already has great bass. I mean really, really good. Tight, dynamic and basically perfect. But the effect of the Silmics is inconsistent here. On some songs it turns up the bass from 10 to 11. On others it does nothing. However, it does soften the treble a bit. It’s not removing detail, just making it softer and so these are nice quick mods to have available for recordings that are too hot or fatiguing for one reason or the other.
 It’s the chill-pill. If you have HD800's you will probably want to try this for sure.
 Another beautiful quality of the Burson SS V5 is how it handles both male and female voices. The entire range is available. Silky, squeaky, husky, smokey and natural. The details and dimensionality of the Bursons almost puts a face to the voice you are hearing.
 Sibilance has always been an irritation for me and in the beginning of my amp building and opamp and cap rolling I was trying to eliminate it. However, it is oftentimes in the recording. One cannot say “silly sandwich” without producing it. But how the opamp treat those sounds is what matters. The Burson does not create sibilance that is not on the recording, and it does not hide it either.
 I find the LME49990 with Silmics does mask the sibilance superbly but I have not yet had the desire to run the LME49990 again compared to these.
  
*Here are some interesting observations with and without the Silmic on the Bursons.*
  
 James Blake: Overgrown
  
Silmic: Very lush. You can feel the bass in your chest. Vocals are not near, they are on you, in you. This is very close and intimate and for a happily married hetero male, almost uncomfortably close 
	

	
	
		
		

		
		
	


	




, but if you want to be sung to and wrapped into the music this is the way to go. This really is a very remarkable experience.
No Cap: Beautifully articulated bass. It is tight. Instrument separation is perfect. The voice is moved back just a bit compared to the silmics. There is a touch more sparkle at the very top.
  
 James Blake: To the Last
  
No Cap: The bass is completely extended. This song has a percussive “tick” that on lesser opamps is just kinda there. On the Bursons it has a specific location and even extension into space. The rasp of James voice is so detailed.
Silmic: The percussive “tick” is less sharp and feels less extended into space. There is less air and depth. The soundstage is smaller than without caps. The rasp is still detailed but less sharp. 
 On this song silmics do not improve the music.
  
 Blue Coast Collection #1: Looking for a Home
  
Silmic: Guitar left and guitar right. The sound is full. Voices are distinct at 12'00 and 2'00
No Cap: Just a tad bit lighter, cooler. More background ambiance.
  
 Yo-Yo Ma, The Goat Rodeo Sessions: Attaboy
  
Silmic: Very warm and musical.
No Cap: Lighter. Cooler, tempo feels just a bit faster.
  
 Thievery Corporation, Saudade: Meu Nego
  
No Cap: first time I have ever heard noise from the needle on the record. At first I was thinking there is something wrong with my connections. Checked connections. Checked that opamps were properly seated. Checked that headphones were plugged in correctly etc.. until I figured out I am hearing needle noise from one of their samples in the recording.
Silmic: The needle noise is still there, but muted. With regular opamps I hadn’t really ever paid that much attention to it and am not sure I was even aware of the needle sound.
  
 The equipment I am running here is a Xonar as DAC going to a variation of The Wire as headphone amp. The wire is a very simple design that has an opamp for I/V and then is followed by LME49600 as buffer. I run mine at +- 15V. This then goes to the HD650 manufactured in 2014. There are a few interesting observations that need to be mentioned here. My headphone amp with LME49990 produces about 1mw of DC offset on the right and 2mw on the left channel. Perfectly acceptable.
 With the Burson in I/V it produces 0.01mw offset. That’s amazing and hats off to the Burson engineers.
 Another is that it is deathly silent. I thought the LME49990 was silent but comparing it to the Burson there is the faintest of background noise on the 49990. However, the Burson is just .. nothing.. no difference between on and off.
 At this point I need to give props to the HD650. These scale incredibly well. All this detail that the Bursons are digging up is there. An incredible sense of air and space unlike any lesser phones I had tried. I have looked over my shoulder more often during this evaluation, thinking I heard someone walking or saying something only to find out that its part of the recording.
  
*So what are the downsides?*
  
 Size is one. This will not fit in a small enclosure. I currently have the side pulled off of my computer and the Bursons are sticking out. This means that I can’t close this case until I get a bigger case because I have no intention of taking the Bursons out again.
 Price is another. These are not cheap. However, they are worth it. If I look at my opamp collection, I have spent at least a few hundreds of dollars on these little buggers over the years. (I really hope my wife never reads this post) One single LME49713HA on Digi-Key costs $11.78 right now. And I went through 4 because they are difficult to work with and I killed the first pair. That’s just one model.
 So what am I saying? If money is tight, then start with at least one SS V5. The most important one is in the headphone amp. After that, the most important position is the I/V of the soundcard.
 If you need to go all the way, get the buffer for the soundcard last. This is an interesting observation. The LME49990 in buffer passes on the magic of the Bursons in I/V just fine but it can’t seem to produce it on its own in the dac or headphone amp.
 What is it like to go back to regular chip opamps? The AD797 feels cramped and the LME49990 sounds grey. Don’t beat me with the “Andrea stick” but I’ll be damned if it doesn’t. When I put the 49990 in the headphone amp everything is just a little flatter, a little less exciting in comparison. Don’t get me wrong, the 49990 and others do sound really great. I was almost completely happy with those for a long time. But the Burson SS V5 is significantly better. This does not mean that my opamp rolling days are over. Now the quest is to find what is better than the Bursons, but at this point, I don’t know where to start looking.


----------



## zilch0md

That is one of the most enjoyable posts I've read on Head-Fi - and so compelling. (Oh, my aching wallet.)

And I love the idea of soldering caps to the DIP 8 sockets. I feel as if even I could manage thus feat without destroying any op-amps.

Mike


----------



## zilch0md

Wow!  I was expecting a show-stopper price for those V5 duals, but they're only $130 a pair!  That's cheap!
  
 http://www.bursonaudio.com/products/supreme-sound-opamp-v5/
  
 If it sounds like I've lost my marbles, you're right - I paid $150 a pair for genuine Muses 02, from Mouser.com and can't get rid of them even at $75 a pair, so I decided to keep them - even though I'm not using them.  Ugggh!
  
 At least the Burson V5 comes with a 30-day guarantee and a lifetime warranty.  I'm in!
  
 Here's a rough mock-up of what the PB2 might look like once I've cut holes in the case for the V5 duals to protrude:
  

  
 A crude drawing, and I think the Burson V5 might stand taller out of the case, but that's what I'm thinking of doing.  I've already got an extra case for the PB2, purchased a long time ago for only $20 (top and bottom), with the idea of drilling vent holes for cooling.
  
 I noticed that Burson sells a pair of 35V 220uf caps for $10 and their DIY page suggests a wide range of possible values.
  
 What argument can you make for selecting 10uf caps instead of 220uf?
  
 I will follow your lead, believe me - I'm just wondering why 10uf.  
  
 Thanks!
  
 Mike


----------



## pelopidas

That actually looks kinda cool having the towers poke out like that. I don't have any skill working with metal, so if you do that make sure to take pics so we can see how you do it
About the 10uf... That was just experimentation. I tried it with a big ass 1000uf a 470uf and then a 10uf. Adding more than 10uf did not improve things. The reason I think, and this is just speculation, is that the sound card already has sufficient capacitance but that the capacitors don't have good sound. Putting a cap right on the opamp "flavors" the power that is already available. Also, I have read enough data sheets where they recommend around 10uf near the opamp for stability so that seemed like a good starting point. I tried small foil caps and only noticed an effect in the upper treble so there needs to be enough current available to move the bass notes too. 10uf seems to be enough to affect the full spectrum. 

My headphone amp has 1000uf + 390uf + 10uf in the power supply portion. Then each opamp position has 470uf, so there is more than enough capacitance. This is just a flavor thing. 

I have always been hesitant to drop that kind of money on the muses. I hear they are all kinds of superlatives but that money is hard to justify to the wife. Why is it that you are not using them? How do they sound compared to the 797 or 49990?


----------



## zilch0md

Thanks pelopidas,
  
 I really like your reasoning for use of 10uf caps, so I'm comfortable with that.  
  
 If I like the sound of the V5s well enough to keep them beyond the 30-day guarantee, I won't hesitate to put that extra case to good use, but I wouldn't dare attempt to cut rectangular holes in it myself. I can very precisely mark where I want the holes, but I have no metal working skills. I would take it to a proper machine shop. 
	

	
	
		
		

		
		
	


	



  
 It's a job a good machinist can do in his sleep for something like $25 to $50, without scuffing or scratching the case beyond cutting the holes. I'm even thinking of having the edges of the holes bevel-cut or quarter-rounded. That could send the cost way up, so I'll have to see what quotes I get before getting too crazy.  
	

	
	
		
		

		
		
	


	



  
 I'm really glad I have an extra case, as they are probably unobtainable now that the PB2 has been discontinued.
  
 Regarding the Muses 02, all I can say is that I much prefer the LME49990 (used with dummy buffers). Like everything else in audio, I had to buy the Muses 02 to audition them, but I found them to have too much color for my tastes and they take the resolution down a notch, as heard with the HD800. (I've never heard the Muses 01, but after wasting $150 on the Muses 02, I'm too chicken to throw another $150 down the drain, experimenting with JRC's offerings.)
  
 I'm a detail hound and even though the OPA1612 offers even more detail than the LME49990, it's too much for the HD800 and almost too neutral, too, if that makes any sense.
  
  

*2x OPA1612 with dummy buffers in the iBasso PB2 * 
 (This is too neutral and too detailed for the HD800 - almost "crystaline" - but I like it a lot with the HD650. Using HA5002 buffers with the OPA1612 is a stunning solution for the LCD-2 rev.1. My opinions, of course.)
  
  
 For the HD800, the LME49990 has been "just right" in the I/V stage, though I wish it had a bit more bass, but everything I've tried in the buffer stage, including more LME49990s...
  

*8x LME449990 in the iBasso PB2 * 
 (I don't like this combination with any headphone.)
  
 ...gives me more power, that I really don't need with the HD800, but LME49990 as buffers also brings down the resolution. Seriously, it's subtle, but there's nothing more transparent in the buffer stage than dummy buffers.  If I need more power (more current) for the LCD-2, the HA5002 are about the best I've found for use as buffers, but I still prefer the sound of dummy buffers with headphones that have better resolution than the LCD-2 can deliver.  The one exception is perhaps when using the LME49990 with LT1028ACN8 buffers - a combination I like for the HD800, where the LT1028ACN8 softens the HD800 a lot less than the HA5002.  (I'm looking forward to trying dummy buffers vs. LME49990 buffers with the Burson V5s.)
  
 Not having decent soldering skills, I've never heard any of my op-amps with caps applied, but as I wrote earlier, I won't hesitate trying my hand at soldering them to some DIP8 sockets, as you did for the V5s. I have about 20 of those to spare, so I can make a mess and try again, many times over, with as many caps as it takes to get it right.  LOL   (About the only soldering I do with any frequency is for adding connectors to DC power cables and such.)
  
 Mike


----------



## P701

pelopidas said:


> /t/432749/the-opamp-thread/5055#post_12185207



When listening to music, does it interfere with satellite tv broadcasts?


----------



## pelopidas

When I know that a satellite will be overhead I take them out so they don't bonk into each other.

edit:
- Perhaps that answer is too dismissive. I don't detect anything weird happening on the AM band when turning on or off or playing music. The opamp is an analog circuit and the cap is on DC. The V5 does get a touch above ambient but I do not in any way suspect that it is oscillating at all. I would need an oscilloscope to really test it, but my guess is that if anything, having another cap on the DC would suppress frequencies and not amplify them. The Burson circuit is really well engineered though. Regular cellphone interference that does get transmitted through regular opamps is filtered out by the V5. -


----------



## zilch0md

I've ordered the V5 duals. 

And some SILMIC II 35V 10uf caps.

Joy!


----------



## pelopidas

I can't wait to hear your impressions. Just give it a full 100 hrs on the Silmic and the v5. They both need a full burn in. 
What equipment will you be using it in?


----------



## zilch0md

pelopidas said:


> I can't wait to hear your impressions. Just give it a full 100 hrs on the Silmic and the v5. They both need a full burn in.
> What equipment will you be using it in?


 
  
 The only gear I own in which I can roll op-amps is the iBasso PB2 Pelican (balanced portable amp), previously pictured, above:
  

  
 I will be using the two V5 duals in the input voltage stage, with either dummy buffers or the very transparent LT1028 singles as output buffers.
  
 Thanks for the advice regarding 100 hours of burn-in.  Even Burson says to do this, so I will gladly be compliant.  
  
 Mike


----------



## SpudHarris

pelopidas said:


> Hey Spud,
> I am really curious if you will hear much of a difference on the Lycan if you bypass the opamps with silmics. Silmics are what are already being used for the power supply as far as I can tell on the lycan. When your caps come, can you also test the opamps in your Fiquest to see if it behaves similarly or differently?




Hey, well since I got a decent break from work this Chistmas, I indulged in some serious rolling. The results are that the Lycan does still benefit from bypassing but nowhere near as much as the Fi-quest. My favourite bypassed OpAmp on both the Lycan and Fi-quest by a decent margin is the ADA4627-1BRZ. This OpAmp just comes alive with a Simlic II across the power pins. My Fi-quest has become my home amp for the foreseeable future with the HD800's fed from the HP out of the Oppo HA-1.

LME49990 and AD797 are my next favourite bypassed OpAmps. Not got around to modding the V5 yet but as I can realistically only use it in the Lycan I'm not sure there is much mileage in it. Just had some more Simlics II delivered so may give it a go anyhoo....


----------



## Mad Max

spudharris said:


> Hey, well since I got a decent break from work this Chistmas, I indulged in some serious rolling. The results are that the Lycan does still benefit from bypassing but nowhere near as much as the Fi-quest. My favourite bypassed OpAmp on both the Lycan and Fi-quest by a decent margin is the ADA4627-1BRZ. This OpAmp just comes alive with a Simlic II across the power pins. My Fi-quest has become my home amp for the foreseeable future with the HD800's fed from the HP out of the Oppo HA-1.
> 
> LME49990 and AD797 are my next favourite bypassed OpAmps. Not got around to modding the V5 yet but as I can realistically only use it in the Lycan I'm not sure there is much mileage in it. Just had some more Simlics II delivered so may give it a go anyhoo....


 
  
 4627 is still my all-time favorite, I'll be sure to try it out soon with the Silmic II caps I ordered a while ago.


----------



## zilch0md

Pelopidas,
  
 I like this photo so much, I cleaned it up.


----------



## Audio Addict

zilch0md said:


> Pelopidas,
> 
> I like this photo so much, I cleaned it up.




You can't do that with the v5 single, can you?


----------



## zilch0md

audio addict said:


> You can't do that with the v5 single, can you?


 
  
 Yes, you can, but for the single you would use Pin 4 and Pin 7, where for a dual you would use Pin 4 and 8.
  
 Have a look at trooper05's post:
  


trooper05 said:


> Here is the pinout for both a dual or single OPAMP:
> *DUAL*                                                  *SINGLE*
> 
> 
> ...


----------



## Audio Addict

zilch0md said:


> Yes, you can, but for the single you would use Pin 4 and Pin 7, where for a dual you would use Pin 4 and 8.
> 
> Have a look at trooper05's post:




Thanks 

That must be difficult to solder and have the capacitor be in front.


----------



## zilch0md

audio addict said:


> Thanks
> 
> That must be difficult to solder and have the capacitor be in front.




I hate soldering, as I just don't get it, but I'll soon be attempting this myself. I really like pelopidas' idea of soldering the caps to reusable DIP8 extenders instead of to lots of individual op-amps, especially since my favorites, the LME49990, have been discontinued. (I wouldn't want to damage them.)


----------



## Audio Addict

zilch0md said:


> I hate soldering, as I just don't get it, but I'll soon be attempting this myself. I really like pelopidas' idea of soldering the caps to reusable DIP8 extenders instead of to lots of individual op-amps, especially since my favorites, the LME49990, have been discontinued. (I wouldn't want to damage them.)


 
  
 I have absolutely no soldering skills and to avoid burning everything in sight have no soldering tools


----------



## pelopidas

Soldering is not so difficult. Just start by soldering some wires together for practice. Once you have the feel for it, you will find it a useful skill.
 So, I have a few caps that I am now playing with. I'm not quite ready to spill the beans yet but I thought a nice pic would be fun to share.


 In this picture you can see the Muse KZ under the V5. Behind it is a red arrow pointing to a mod that I did a while ago but did not mention till now. Those are the output capacitors. I bypassed them with some wire from one of the legs of a Silmic that I had used in an amp. (I tend to save the clipped legs from the caps since they are oxygen free copper and extremely useful for a tinkerer like me) Since most headphone amps have input caps, there is no reason to have output caps also. Bypassing these is a hugely rewarding 5 minute mod. It is also safer than trying to remove the cap and ultimately is reversible with no damage.
  
 Next up. These are what I am currently playing around with.

 From left to right:
 Panasonic Sepf 22uf 35V
 Nichicon Muse BP 10uf 25V
 Panasonic FC 10uf 25V
 Elna Silmic II 10uf 35V
 Nichicon Muse KZ 10uf 100V (all I could find on short notice)
 FT-1 Teflon 0.018uf
 K73-17 3.3uf
  
 Thanks to Spud for bringing the bipolars to my attention. I have some first impressions on these caps but until I get them all burned in I will reserve my opinion to make sure I am accurate.
 Once I knew that just adding a cap to the dip adapter works I ended up shortening the cap legs to make it look less stupid. This is ultimately a much more economical way and safer way of trying these out since you don't need to buy caps for all your opamps. You can reuse the same cap for all and you don't need to touch your opamps with a soldering iron.


----------



## SpudHarris

I love soldering and have become very proficient over time, I get great enjoyment in creating things for my favourite hobby. Cables, OpAmp mods, Cmoys, Headphone mods etc... I enjoy it immensely.

You guys should get into it honestly... However, if you guys need these DIP adapters? I have loads of gold plated sockets and a limited qty of Simlic II's so can knock a few up if you cover parts and postage....


----------



## pelopidas

spudharris said:


> Hey, well since I got a decent break from work this Chistmas, I indulged in some serious rolling. The results are that the Lycan does still benefit from bypassing but nowhere near as much as the Fi-quest. My favourite bypassed OpAmp on both the Lycan and Fi-quest by a decent margin is the ADA4627-1BRZ. This OpAmp just comes alive with a Simlic II across the power pins. My Fi-quest has become my home amp for the foreseeable future with the HD800's fed from the HP out of the Oppo HA-1.
> 
> LME49990 and AD797 are my next favourite bypassed OpAmps. Not got around to modding the V5 yet but as I can realistically only use it in the Lycan I'm not sure there is much mileage in it. Just had some more Simlics II delivered so may give it a go anyhoo....


 
  
 Man I cant believe I have to buy some 4627's now 
	

	
	
		
		

		
			




 Those things are 10 bucks each and I need 6 ... damn..
 So tell us, what is your impression of the silmics on the Fi-quest? How does the 4627 compare to the output bypassed 5534?


----------



## pelopidas

Ok, what do you do when you don't want to spend 100 hrs per cap to burn them in? You create an abomination and burn them all at once!
  
 I call it the Tower of Power 
	

	
	
		
		

		
		
	


	





  
 Its so damn ugly I wont let it anywhere near my good equipment and have it plugged into a cmoy. But it works. After measuring DC offset at 2mw I even gave it a listen. It works and sounds pretty ok but not excellent. There are some weird harmonic issues which could also be the endless connections or the fact that I am listening to a 49720 instead of the Burson. I am not going to let the V5 anywhere near this.
 I tried this with the 49990 and the 797 too and surprisingly it is stable. No oscillation or heat whatsoever.


----------



## zilch0md

I received my V5 duals today (16 days).
  
http://www.head-fi.org/t/784790/burson-supreme-sound-audio-v5-opa-d-v5-opa-s-review/75#post_12253412


----------



## zilch0md

More whining combined with sincere praise for the V5 Duals:
  
 http://www.head-fi.org/t/528149/ibasso-pb-2-pelican-fully-balanced-portable-db-2-dac-hiflight-recommended-op-amps-page-16/1305#post_12260674


----------



## justbenice

Hi all.
 Can i upgrade Ne5532 in my CDPlayer to Muses01 ?


----------



## Michael V

My burson v5 opamp is coming in soon and I want to add the capacitor to it so I bought the silmic II 10uf and spare sockets. I've never dealt with op amps or capacitors before so I'm slightly confused. I just want to have everything ready for when my burson comes in.  
  
  
 I was looking at this diagram and when I receive the burson how do I tell which side is which?


trooper05 said:


> Here is the pinout for both a dual or single OPAMP:
> *DUAL*                                                  *SINGLE*
> 
> 
> ...


 
  
  
 Also there is a half circle on one side of the socket, does it matter which direction you plug the burson into the socket? Thanks


----------



## Michael V

Nevermind I figured it out by looking at pictures posted previously. It was so easy even a noob like me could do it lol! I just have it connected to my opa2017 for now until my burson comes in.


----------



## zilch0md

Nicely done!  
  
 What did the cap do for the sound of your OPA2017?  Anything noticeable?


----------



## kahei036

michael v said:


> My burson v5 opamp is coming in soon and I want to add the capacitor to it so I bought the silmic II 10uf and spare sockets. I've never dealt with op amps or capacitors before so I'm slightly confused. I just want to have everything ready for when my burson comes in.
> 
> 
> I was looking at this diagram and when I receive the burson how do I tell which side is which?
> ...


 

 Hey Mike..
 Base on your second pic it seems you have connected the bypass cap to pin 1 and 5 instead of the vcc+ and vcc-..
 Hope you've already figured this out got it soldered correctly..
  
 The arc on IC socket usually indicates it's the "up" side of the IC; you probably will notice a "dot" on an IC, that usually indicates it's pin1 (datasheet would proobably the best to tell). And this dot usually is in same direction as the arc on an IC socket.


----------



## Michael V

zilch0md said:


> Nicely done!
> 
> What did the cap do for the sound of your OPA2017?  Anything noticeable?


 
 So far it seems to just have given songs a blacker background and instruments are slightly clearer because of that.


kahei036 said:


> Hey Mike..
> Base on your second pic it seems you have connected the bypass cap to pin 1 and 5 instead of the vcc+ and vcc-..
> Hope you've already figured this out got it soldered correctly..
> 
> The arc on IC socket usually indicates it's the "up" side of the IC; you probably will notice a "dot" on an IC, that usually indicates it's pin1 (datasheet would proobably the best to tell). And this dot usually is in same direction as the arc on an IC socket.


 
 Yea I noticed that before I soldered it and switched it around. Thanks!


----------



## zilch0md

^ you might want to pull that photo from that post before a guy like me (doh!) uses it as a guide when soldering. I had already saved the photo. 

Thanks!


----------



## Michael V

zilch0md said:


> ^ you might want to pull that photo from that post before a guy like me (doh!) uses it as a guide when soldering. I had already saved the photo.
> 
> 
> 
> ...


 
 Yea good idea lol, just removed it.


----------



## zilch0md

^ Thanks!  Hopefully, kahei036, to whom I am grateful for noticing the problem, will do the same in his having quoted your post.


----------



## RamGuy

I'm considering to change the op amps on my Xonar Essence One and I'm considering going for 4x Muses 01 or 4x LME49990 for the IV's, and 2x Muses 01 + 2x Muses 01 for Low-Pass and buffers or perhaps 2x Supreme Sound Opamp V5 + 2x Supreme Sound Opamp V5 if they would even fit inside the Xonar Essence One.
  
 But how would I know if I'm actually getting genuine and legit op-amps? The easiest way to order is through E-Bay but I'm afraid I end up with fake op-amps even when the seller is rated as "Top Seller".


----------



## zilch0md

The LME49990 has been discontinued, so I have to wonder where these sellers are getting them? 

As for the JRC Muses, I ordered mine from Mouser.com, just to be sure they were genuine, but it cost me $150 for a pair, plus shipping! 

I don't how to advise you, except to say that, at least with Burson, you'll be getting real Burson product, and even a pair of V5 duals costs less (at $130) than what I paid for a pair of genuine Muses 02.


----------



## Mad Max

I'm pretty sure it was mentioned in this thread that even if _x_ IC is discontinued, the manufacturer still has orders to fulfill with its clients, so it simply isn't going to take any new orders for that part from now on.  I imagine that opportunities for other sellers to get genuine leftover stocks and what not should continue for quite some time.
 It's a shame that that fine opamp is discontinued.


----------



## ScottFW

ramguy said:


> I'm considering to change the op amps on my Xonar Essence One and I'm considering going for 4x Muses 01 or 4x LME49990 for the IV's, and 2x Muses 01 + 2x Muses 01 for Low-Pass and buffers or perhaps 2x Supreme Sound Opamp V5 + 2x Supreme Sound Opamp V5 if they would even fit inside the Xonar Essence One.
> 
> But how would I know if I'm actually getting genuine and legit op-amps? The easiest way to order is through E-Bay but I'm afraid I end up with fake op-amps even when the seller is rated as "Top Seller".


 

 If it's much less expensive than official suppliers and ships from China/Hong Kong/Taiwan, it's fake. That's my default assumption until somebody else plays the role of guinea pig, lays out their own money, and confirms otherwise. If you want to see a **** show, look at ebay listings for OPA627. For other op-amps where the fakers have actually bothered to make the printing look correct with lot numbers that could possibly have existed, there may be information out there on ID'ing the fakes by other means, such as taking resistance readings between certain pin pairs and comparing against measurements from legitimate chips purchased through official suppliers.
  
 It's not just op-amps that are being faked either. Capacitors are another highly suspicious category. How many people are really going to be able to tell if there's a common cheap electrolytic inside that faked Black Gate wrapper? I've seen fakes on ebay of large value electrolytic caps that were never actually made in a legitimate version by the knocked off brand name. Who's going to know there's a cheap Chinese POS inside that can't withstand the voltage printed on the label, until it BLOWS UP in their circuit? At least with op-amps the potential damage from fakes is mostly confined to your wallet and sense of pride.
  
 The LME499990 sounds pretty darn good to me in CD players and DACs. With its pending discontinuation I've stocked up a few for future personal use. Mouser still has them. They'll have 100 pieces one week, then zero, then they'll get a couple hundred more, etc. Keep checking back but I'd advise anyone with even potential interest to pick up a few before production ceases, while they're still $3 apiece.


----------



## zilch0md

mad max said:


> I'm pretty sure it was mentioned in this thread that even if _x_ IC is discontinued, the manufacturer still has orders to fulfill with its clients, so it simply isn't going to take any new orders for that part from now on.  I imagine that opportunities for other sellers to get genuine leftover stocks and what not should continue for quite some time.
> It's a shame that that fine opamp is discontinued.


 
  
 That makes sense, thanks.  And it's good news. Maybe I should buy spare set of LME49990 while I can.


----------



## RamGuy

I notice that some users on various known forums have good experience purchasing from "hifiic on ebay, but I'm still rather sceptical. Ordering for Mouser.com is not that tempting as I do not plan to do any soldering myself and they seem to only sell SOIC and nothing soldered to DIP8.
  
  
 When it comes to various op amps I'm tempted on going all out on the LME49990 as they are very affordable and have great reputation. The Muses are darn expensive and I hear about a lot of people that end up with not liking them too much. Everyone seems to claim that changing the IV's is the best place to start and that would mean I need to get 4x Muses and that's just ridiculously expensive. Same goes for the Burson's compared to LME49990.
  
  
 From what I can gather people seem to change IV's and buffers, but no one seems to be mentioning the Low Pass Filter. According to the op amps manual for my Asus Xonar Essence One they claim that these op amps are the ones that will affect headphones;
  
 2x Low Pass Filter
 4x IV's
 2x Buffers
  
  
 Is the reason for no one mentioning the Low Pass Filter because it's a waste to change it? Is the low pass filter something unique and special so using the same op amps for low pass is not ideal?
  
  
 I was thinking of trying out;
  
 2x LME49990 for Low Pass Filter
 4x LME49990 for IV's
 2x Dual LT1057ACN8 for Buffers


----------



## zilch0md

The Muses 01 and Muses 02 are duals, so you would only need two instead of four, but they are still crazy expensive at $150/pair from Mouser.com.  I've never heard the 01's, but don't like my 02's as much as several other less expensive op-amps. The 01's seem to be more popular.
  
 I would be tempted to just leave the Low Pass Filter alone.  An LPF determines the roll-off of the highs and I can't imagine how you'd go about finding an op-amp that would impact this, as they're pretty much all striving for no attenuation at 20kHz.  
  


> I was thinking of trying out;
> 
> 2x LME49990 for Low Pass Filter
> 4x LME49990 for IV's
> 2x Dual LT1057ACN8 for Buffers


 
  
 I like your plan except for the LPF (but for the price of two LME49990, you might as well try it).  I think that once you go to this combo, everything you try thereafter could be a let down.


----------



## RamGuy

Ended up with saying "**** it" and purchased 6x LME49990 + 2x LT1057ACN8 + 2x Dual DIP8 to DIP8 adapters from "hifiic" on Ebay.


----------



## zilch0md

^ Awesome! Have fun!


----------



## zilch0md

pelopidas said:


>




This looks as if the cap's negative lead is soldered to V- (Pin 4).



And this looks as if the cap's negative lead is soldered to V- (Pin 4)



So what's wrong with this next photo by Michael V? It looks the same, to me:



Isn't the cap's negative lead going to V- (Pin 4) and the positive lead to V+ (Pin 8)? Just like the caps soldered by pelopidas?

*[COLOR=FF00AA]UPDATE: No. In this photo, the DIP8 extender is upside down. The cap's positive lead is going to Pin 1 and the negative lead to Pin 5, which is wrong, as pointed out by kahei036, previously. [/COLOR]*

Here's another cap done by pelopidas, where the negative lead is going to V- (Pin 4):


----------



## zilch0md

kahei036 said:


> Hey Mike..
> Base on your second pic it seems you have connected the bypass cap to pin 1 and 5 instead of the vcc+ and vcc-..
> Hope you've already figured this out got it soldered correctly..
> 
> The arc on IC socket usually indicates it's the "up" side of the IC; you probably will notice a "dot" on an IC, that usually indicates it's pin1 (datasheet would proobably the best to tell). And this dot usually is in same direction as the arc on an IC socket.




Was your correction of Michael V incorrect?

*[COLOR=FF00AA]UPDATE: I've since figured out that your correction of Michael V was indeed correct. I apologize for confusing things further.[/COLOR]*


----------



## Michael V

I fixed it a while ago because I had to flip around the cap. So it looks like this now
  

  
  
 I used this picture as reference


----------



## zilch0md

michael v said:


> I fixed it a while ago because I had to flip around the cap. So it looks like this now






 Now, your negative lead is going to Pin 5 and your positive lead is going to Pin 4.

 I think your were (unintentionally) mislead by kahei036

*[COLOR=FF00AA]UPDATE: You now have it correct, as shown above. kahaei036 was right. [/COLOR]*


----------



## zilch0md

I'm sorry! That's it... The diagram I'm using is a top-down view, where your photos have beem bottom-up.

Sigh...


----------



## Michael V

zilch0md said:


> Oh wait! Is it because the diagram I'm using is a top-down view?
> 
> Confused!


 
 possibly because this person would be doing it wrong too then


----------



## zilch0md

michael v said:


> possibly because this person would be doing it wrong too then




You're photos match those of pelopidas - you're both doing it the same way. And I think we can trust his experience.



UPDATE: For my own sake, if no one else's.


----------



## zilch0md

It is done!  I've finally soldered some caps to something!  LOL
  
 Here's the stuff nobody tells you - I had to figure it out on my own...
  

  
 Within two seconds of touching the soldering iron to the pin, the pin got so hot, it melted the surrounding plastic and pushed out the far side.   Doh!
  
 I had it set to 400C, so I bumped it down to 200C, but that wasn't hot enough to desolder the lead from the damaged pin.
  
 So, I tried 300C - just right!  
  
 That's what she said!  (Goldilocks, that is!)
  
 So, here's my 3rd attempt, this time, with shorter leads:
  
  
  
  
 The soldering went surprisingly well.
  
 Scotch Tape is my friend!  
	

	
	
		
		

		
			





  (To hold stuff where I want it.)
  
 You can't tell from this angle, but the pins are clear of solder - it's only wrapped around the base of the pins.
  
 Maybe I can actually solder stuff after all!  LOL
  
 And here they are installed underneath the Burson V5 Duals, in my iBasso PB2, with 4x LME49990 as buffers:
  

  

  

  

  
 And the sound is most definitely improved!  I find this so hard to believe, given how thrilled I've already been with the Burson V5 Duals - nine days and counting.  
  
 I'd say the biggest difference the caps make is in improving dynamics. Going back to having no caps sucks some life out of my most dynamic recordings. It's not subtle, but it's not night and day, either. It is readily detectable, though - especially with tracks having momentary signals that demand a lot of power, like drum hits. And the bass is more tightly controlled - as evidenced with any textured electronic bass (Daft Punk, Hans Zimmer, etc.)  But acoustic bass is better, too. My HD800 loves the Burson V5s with caps!
  
 Here's a shot taken before I added the caps:
  




  
*Tidal HiFi  and Onkyo HD Player > iPod Touch 6 > Zeskit rt. angle Lightning -to- USB A cable > Oppo HA-2 Line Out > Cardas HPI (Litz wire) rt. angle 3.5mm interconnect > iBasso Pelican PB2 with Burson 2x V5 Duals in I/V and 4x LME49990 as buffers, on High Gain, balanced out > Toxic Cables Silver Poison > Sennheiser HD800*
  
 I've been listening to music instead of finishing this post, but now I want to gush about how great this sounds. 
	

	
	
		
		

		
		
	


	



  
 The noise-free nature of battery power has a lot to do with the success of this rig, I'm sure, but it starts with how the iPod Touch 6 is dead silent. I've been using it and, previously, an iPad 3 as my source for my desktop rig, too - pulling digital out of them has made them my favorite source - better than my laptops, for sure.  The Oppo HA-2 supports Hi-Res files from iDevices without the need for a CCK and USB receiver.  The HA-2's ES9018K2M DAC implementation is amazingly transparent and detailed.  The treble is well separated and clean, with none of the brittle edginess the HD800 so readily discerns with lesser DAC/amp combinations.  It has none of the glare I can hear with the Oppo HA-1's ESS9018 DAC - which the HD800 hates.
  
 The soundstage and imaging are crazy good - definitely a benefit of using the Burson V5 Duals - much, much better than I've heard with LME49990, OPA1612, Muses 02, or anything else I've tried in the PB2 I/V stage. 
  
 Detail is through the roof, but not at all sibilant or fatiguing.  Even before adding the caps, I would have said the bass is amazingly tight and deep - not what most people associate with the HD800, but now it can absolutely *growl*, with lots of texture and speed. It still sounds like an HD800, not something a true bass head would want, but the bass is at an energy level that I like - very natural - realistic.
  
 The dynamics are stunning, with drum hits having lots of bite. This is something I can't get from my Metrum Acoustics Octave MkII and Aurix stack - which really has me scratching my head - that a portable rig could sound so good.  Vocals are natural sounding. Drums, piano, and acoustic guitar are all so "real."  (Thank you, Burson!)  Oh, and cymbals - they are so delicately and naturally defined that I've come to really enjoy them as never before. (They sound like real cymbals instead of like rubbing two blocks of Stryofoam together.)  
  
 Despite the awesome resolution, this rig remains _versatile -_ not nearly as unforgiving of less than ideal recordings as I would expect for so highly resolving and transparent a DAC and amp combo.  The more I listen to this rig, the more I cannot believe it's happening. I've had the Burson V5 Duals for nine days now, and the honeymoon is only getting more passionate!  Everything else I have to do with my time, going to work, running errands, whatever life demands, has become a distraction to getting back to the pleasure of enjoying this rig.  (I took the day off from work to get the soldering done, because I was too busy with other domestic stuff over the weekend!  LOL)
  
 I've rolled many combinations of op-amps through the iBasso PB2 over the past few years, but nothing has hit me over the head like these Burson V5 Duals, in combination with all the other pieces of this rig - and adding the caps has just kicked it up even more.
  
 I took it to work with me last Friday (with the caps not yet applied) and spent about twenty minutes in a quiet conference room, with each of two co-workers, pulling up their favorite tracks with Tidal HiFi, in addition to playing several of my favorites.  They were both slack-jawed with awe.  And these are guys with whom I've demo'd some of my previous portable rigs, over the years. 
  
 I'm almost ready to stop asking myself that ever-present question:  Does it get any better than this?
  
 Next step: Get some holes machined into the top of a spare PB2 case I ordered from iBasso, so that the Burson V5's can stick out - like a blower through the hood of a muscle car.  
	

	
	
		
		

		
		
	


	



  

  
 OK, that's enough gushing for now.  
	

	
	
		
		

		
		
	


	



  
 Thanks for your trailblazing efforts, pelopidas.  And thanks to Michael V, too - for getting me sorted out on which pins to solder.  
	

	
	
		
		

		
		
	


	



  
 Joy!
  
 Mike


----------



## sceleratus

I'm pretty much just a solder monkey but I though ya'll might be interested in these.
 There's used in the design of the balanced preamp I built and I love the sound...
  
  
THAT1200
  
THAT1646


----------



## zilch0md

^ I'm humbled.


----------



## sceleratus

Certainly not by me.


----------



## zilch0md

zilch0md said:


> ^ I'm humbled.


 
  


sceleratus said:


> Certainly not by me.


 
  
 Yes - by your apparent soldering and DIY skills. I'm humbled_ and_ envious that you can craft things at will. I tend to be all thumbs.


----------



## sceleratus

zilch0md said:


> Yes - by your apparent soldering and DIY skills. I'm humbled_ and_ envious that you can craft things at will. I tend to be all thumbs.


 

 You have no idea.  I'm laughing.   First.  I can't understand a simple circuit with 2 resistors.  I've been doing this about 2 1/2 years.  I have learning issues.  However I'mm pretty intuitive and I can follow directions.  I learned to solder after watching Dave Jones EEVBlog 3 part tutorial.  (On his site or YouTube) Once you watch them you'll be able to solder most anything.   He uses a Hakko FX-888.  I gout one and I Love It.    I'm sure others like other brands.
  
 So.  Go watch them and tell me what you think.


----------



## zilch0md

LOL
  
 Well, I feel silly now, having made so many assumptions, but I think it's safe to say you're still out in front of me in soldering skills.  
	

	
	
		
		

		
		
	


	



  
 I found the links.  Time to figure out what I'm doing wrong.  
	

	
	
		
		

		
		
	


	



  

  
  

  
  

  
 Thanks for the recommendation!
  
 Mike


----------



## sceleratus

After Dave's tutorial I can solder SMD component smaller than a grain of rice. 

None of this has to do with Op-Amps. Sorry
Im not even qualified to be on this thread. Not sure why I'm here. 
Oh ya. THAT IC's. If you know what they do I think you'll like them
Again Sorry for the hijack


----------



## P701

Guys when you are soldering different capacitors on single op-amps for its power connectors, and judging how they change sound to your liking or disliking... Have you ever thought that there most likely will already be factory soldered capacitors on the pcb of the device youre using, for the exact same power rails as opamps + & - pins? What if those capacitors colors and saturates your sound too and makes your opamp sound worse (or better)...
Kind of.... how can you judge your brand new all-shiny single capacitors sound, soldered on your opamp pins, when there may be combinations of other capacitors adding their own "sound" to it aswell. What if those capacitors are actually taking over the majority of the sound?

I guess, some were very gifted having such a great audio memory that they can remember and hear differences prior and after having soldered a capacitor on a power pins.... yes, power pins.


----------



## zilch0md

^ I can see your point - Burson Audio has an article that recommends similar mods:   http://www.bursonaudio.com/tweaks-for-geeks/
  
 But I'm not willing to experiment with replacing the caps already used by my amp, much less try the many possible combinations to see which sound best. I just don't have the soldering skills - or the will.
  
 Burson sells 35V 220uF SILMIC II caps for the "convenient" price of $5 each, to use as power-coupling caps with their Burson V5, but I went with the advice of pelopidas, to solder 35V 10uF caps to removable DIP8 sockets, instead of to the op-amps themselves - for the Burson V5.
  
   
  
 My aural memory is sufficient to easily discern that these improve the sound - to my liking - when inserted  beneath the Burson V5 Duals in my iBasso PB2.  Taking them out after a few hours of listening makes it even more obvious.  
  
 I do agree that it would be awfully difficult to A/B when soldering directly to an op-amp's power pins. 
  
 And yes, it's possible that a different value or type of capacitor would sound better still and it's possible that replacing the default caps on the iBasso PB2's PCB could make an audible improvement, but I'm not a well-seasoned solder monkey.  It took me about five hours, start to finish, to produce what you see in the photo, above, after making several mistakes. The soldering itself had to be "mastered," but harder still was just figuring out how to cut and bend the leads, sculpting them to be as short as I dared make them, yet still have room to bend them upward to clear my other op-amps, once inserted. It was a royal pain for an "all thumbs" guy like me, also having to wear two pairs of reading glasses just to see what I was doing.  
  
 So, I'm done for now, but I'm really glad I pushed past my inabilities to get as far as I have.


----------



## Michael V

null-


----------



## zilch0md

michael v said:


> Finally received my burson and realized it made no difference compared to the opa2107. I've used it for about 20 hours now and doesn't sound any different. I've used it with and without the capacitor and the only difference is with the capacitor the background is silent. So i went ahead and compared my computer with an Asus Xonar stx soundcard and little dot 1+ hybrid amp with voskhod tubes and the burson opamp and compared it to my headphones connected straight to my iphone6s+ and literally did not hear one difference with my grado RS2e and sennheiser hd 598 headphones. This make me think that either these headphones don't benefit from a DAC and amp at all or that DACs and amps don't make a difference and it's all placebo. I'm at a loss currently and I'm thinking about selling all my audio gear except for my headphones


 
  
 I can't recall if you've done any other op-amp rolling, but I will admit that op-amps are way down on most people's lists of components ranked by their impact on sound quality - which typically goes something like this:
  
 Headphones
 Recording (quality of a track)
 Tubes
 Amps
 DACs
 Sources
 Op-amps
 Analog cables
 Digital cables
  
 And I can tell you that when I first started rolling op-amps in the iBasso PB2 about four years ago, I felt the same as you.  I mean, they all sounded pretty much the same.  But by trying different combinations and listening carefully, I slowly developed an ability to listen more critically - more analytically. I stopped listening to music with my intuition and started listening with the more logical side of my brain.
  
 I can't honestly say that the journey was altogether a positive experience, because the more discerning your ears, the less you can enjoy poorly reproduced sound.  So, in a way, I actually envy your inexperienced ears.  
  
 Note that I'm not saying I was born with better ears than anyone else. I genuinely believe that, short of any health problems with our hearing, we can all become more "discerning" with experience.
  
 So, don't be too hasty, but yeah, I can empathize with your perspective - that the money was not well spent, in your case.  And that's a perfectly valid complaint.
  
 There's no right or wrong, here. I know a guy who swears the least expensive wine he can enjoy costs him $25 a bottle when he buys it by the case, so he's not really happy with the price he's paying, but with experience, he has grown to detest the wines that he can actually afford.
  
 I want to tell him, "Suffer!"  
	

	
	
		
		

		
		
	


	



  
 He says there are some $100 wines (and higher) that he drinks on special occasions, that are "to die for."  
  
 No thanks!  I'd rather stay "inexperienced" than go through what he's suffering.  Keep me away from the good stuff!
  
 Don't hesitate to spend your hobby dollars elsewhere. As it is, I'm caught in the whirlpool, but I keep myself on a very tight spending budget when it comes to audio. It's a bottomless pit.


----------



## SpudHarris

Mike, wise, wise words my friend!

Your journey has been the same as mine to the tee... We all have to start somewhere but most of end up at the same place. A place where the slightest improvement is disproportionate in cost and unless you have a bottomless wallet, we have to say enough is enough.

Critical listening may be a PITA at some point but eventually (hopefully) you get to point when you say "you know what?, I am happy with my set up given my budget so now I'm going to revisit my music collection"

I reached this point fairly recently but then decided to re rip all my CD's in FLAC  (used to be a fruit based supporter). So now I am happy and my tweaking is purely for fun and not an active search for something better. If money becomes no object at some point in the future, I'm not convinced I would change where I am now. I listen to my tunes at least 2 hours a day and am convinced it really can't get "much" better.

OpAmp rolling, like you say is way down the list of tweaks and will never be night and day, more one of the final preferences dependant on extensive listening and genre choice.

It's a journey but it's a great journey and there is no better place than Head-Fi to help and support you along the way.


----------



## leeperry

Blind opamp rolling is plain idiotic anyway, pros on diyaudio such as Scott Wurcer consider us to be total morons when we talk about opamps such AD797 adding a sonic color of their own duh...Andrea became quite a VIP there, well..before he got banned at least lol...mostly because an opamp needs to have a custom tailor-made surrounding circuit of its own and the higher range the chip the worst it'll get due to its extreme sensitivity, blind rolling of LT1028 or AD797 will end up having 99% risks of having the chip oscillating so at the end of the day we'll be posting subjective impressions regarding its malfunction and how trebles are a little zing and bass a little zung duh, reason why a cheaper opamp can sound a lot better when not rolled by monkeys but actually properly implemented by an EE. I'm currently impressed by Muses8920, god forbid ^^


----------



## zilch0md

spudharris said:


> Mike, wise, wise words my friend!
> 
> Your journey has been the same as mine to the tee... We all have to start somewhere but most of end up at the same place. A place where the slightest improvement is disproportionate in cost and unless you have a bottomless wallet, we have to say enough is enough.
> 
> [snip]




Indeed! About the only thing I can add, for Michael V's sake, is that sometimes, an upgrade is premature relative to some other, much weaker links in the chain. Installing anti-sway bars in hopes of improving the handling of a 1960s era muscle car will be difficult to appreciate if it still has drum brakes, leaf springs and heavy steel rims. 

You just have to keep building until, suddenly, things begin to gel. You'll know it when it happens. If the journey offers more frustration than fun, it's not for you - and again, that's perfectly valid. 

It's a shame we can't walk into a giant laboratory and play mix and match with all the latest head-fi gear, until we leisurely figure out what sounds best to each his own tastes.

Mike


----------



## Mad Max

leeperry said:


> Blind opamp rolling is plain idiotic anyway, pros on diyaudio such as Scott Wurcer consider us to be total morons when we talk about opamps such AD797 adding a sonic color of their own duh...Andrea became quite a VIP there, well..before he got banned at least lol...mostly because an opamp needs to have a custom tailor-made surrounding circuit of its own and the higher range the chip the worst it'll get due to its extreme sensitivity, blind rolling of LT1028 or AD797 will end up having 99% risks of having the chip oscillating so at the end of the day we'll be posting subjective impressions regarding its malfunction and how trebles are a little zing and bass a little zung duh, reason why a cheaper opamp can sound a lot better when not rolled by monkeys but actually properly implemented by an EE. I'm currently impressed by Muses8920, god forbid ^^


 
  
 I sure love the recording (and playback) quality of my opamp-rolled Tascam US-122MkII, even though the circuitry is made for NJM4580 rather than the ADA4610s I rolled in.  Maybe there are really pleasant/musical distortions coming from those ADI opamps, who knows?  At least the chips aren't oscillating, lol.


----------



## zilch0md

leeperry said:


> Blind opamp rolling is plain idiotic anyway, pros on diyaudio such as Scott Wurcer consider us to be total morons when we talk about opamps such AD797 adding a sonic color of their own duh...Andrea became quite a VIP there, well..before he got banned at least lol...mostly because an opamp needs to have a custom tailor-made surrounding circuit of its own and the higher range the chip the worst it'll get due to its extreme sensitivity, blind rolling of LT1028 or AD797 will end up having 99% risks of having the chip oscillating so at the end of the day we'll be posting subjective impressions regarding its malfunction and how trebles are a little zing and bass a little zung duh, reason why a cheaper opamp can sound a lot better when not rolled by monkeys but actually properly implemented by an EE. I'm currently impressed by Muses8920, god forbid ^^




I hear you. If you're willing to take the risk of breaking something, just plug them in and let your ears decide. I do, however, check the op-amp datasheets for supply voktage min. and max. specs.


----------



## leeperry

zilch0md said:


> I hear you. If you're willing to take the risk of breaking something, just plug them in and let your ears decide. I do, however, check the op-amp datasheets for supply voktage min. and max. specs.


 
  
 These aren't lego bricks by a very long shot and there's a million factors beyond their min/max voltage spec, datasheets are here for a reason.
  
 Facts are that I usually prefer single opamps because nothing is shared, the OPA1612 datasheet makes clear that both channels are supposedly more separated than in regular dual opamps and some EE's prefer dual opamps because both channels would be closer specs-wise.
  
 I can certainly hear that Muses8920's SS is colored but it makes so much sense and sounds so great huh.....hardpan on the SS extremes sounds like whispers to my ears but then again I haven't played hardball and rolled 49990, 4610, 4627 and so on yet 
	

	
	
		
		

		
			




  


mad max said:


> I sure love the recording (and playback) quality of my opamp-rolled Tascam US-122MkII, even though the circuitry is made for NJM4580 rather than the ADA4610s I rolled in.  Maybe there are really pleasant/musical distortions coming from those ADI opamps, who knows?


 
  
 Well yeah: https://www.youtube.com/watch?v=ShvcF8ZgSTk
  
 Nothing beats the fun of painstakingly soldering opamps onto a DIP8 adapter and listening to your new frankenstein arising because we are obviously smarter than EE's, right.


----------



## zilch0md

leeperry said:


> [snip]
> 
> Nothing beats the fun of painstakingly soldering opamps onto a DIP8 adapter and listening to your new frankenstein arising because we are obviously smarter than EE's, right.




I can know that I lack knowledge, yet still opt to roll the dice and try something I've been advised not to do. After doing so, if I am incapable of perceiving any evidence of failure, but instead see some measure of success, I can celebrate having taken the risk in ignorance. In other words, I don't have to arrogantly imagine myself to be smarter than an EE to play Lego with op-amps. I can acknowledge their superior understanding while blindly taking risks.

And boy, am I glad I have!


----------



## leeperry

A good rule or thumb is whether chips get hot, I've had armies of AD797 turning innocent black boxes into frying pans 
	

	
	
		
		

		
		
	


	



  
 And usually higher grade opamps play nicer with blind rolling(B>A for ADI, U>UA for TI etc).


----------



## zilch0md

I just received a replacement pair of V5 Duals - they are perfect in every way - functionally and cosmetically.


----------



## Audio Addict

That's great. Did you have to send the defective ones back?


----------



## zilch0md

I'm thrilled to answer, "No."   So, I have a great-sounding, but "twisted" pair of V5, in reserve, that I could use at some later date if I ever get a desktop amp that is "rollable" and where there's enough space around each DIP8 socket to accommodate the deformity.  All it would take is a cap or a heat sink or something else in the way to prevent the worst one from being mounted.  The other is very close to being OK, but the bad one wouldn't work in an amp where the DIP8 sockets are right next to each other. 
  
 Meanwhile, my most recent Burson V5 impressions can be found here:  http://www.head-fi.org/t/735828/gustard-h10-high-current-discrete-class-a-output-stage-headphone-amplifier/4350#post_12305650


----------



## Audio Addict

zilch0md said:


> I'm thrilled to answer, "No."   So, I have a great-sounding, but "twisted" pair of V5, in reserve, that I could use at some later date if I ever get a desktop amp that is "rollable" and where there's enough space around each DIP8 socket to accommodate the deformity.  All it would take is a cap or a heat sink or something else in the way to prevent the worst one from being mounted.  The other is very close to being OK, but the bad one wouldn't work in an amp where the DIP8 sockets are right next to each other.
> 
> Meanwhile, my most recent Burson V5 impressions can be found here:  http://www.head-fi.org/t/735828/gustard-h10-high-current-discrete-class-a-output-stage-headphone-amplifier/4350#post_12305650




I thought they would treat you like they did me so I am glad they did.

On a somewhat related note, I had Burson Audio email Larry How at LHLabs and he is testing the V5. Hopefully he will get addicted to their sound signature.


----------



## Mr Goat

Hey!
  
 So i have decided i want to build my own op-amp for a pair of dt990's. I do have basic knowledge how to solder and i have basic electric knowledge, But i have a feeling this wont be enough to build a relatively good amp. So i want to learn more about the parts needed, how a basic and more advanced op-amps work, How to understand what will fit my needs. Pretty much all that jazz so i know what i will be doing before i start the build. 
  
 Also, where do you recommend i turn to get IC's, and other parts i cant find on the Swedish website where i know i can get a hold of components like resistors etc?


----------



## Cjuried

Quite the thread! I am a fan of Intersil CA3080EZ and National Semiconductor LM4562NA for high quality audio applications. Both boasting extremely low noise densities and distortion characteristics. Any other fans of the Op Amps here?


----------



## zilch0md

cjuried said:


> Quite the thread! I am a fan of Intersil CA3080EZ and National Semiconductor LM4562NA for high quality audio applications. Both boasting extremely low noise densities and distortion characteristics. Any other fans of the Op Amps here?


 
  
 I've never tried either of those.


----------



## willowbrook

This probably has been mentioned somewhere, but I can't find any definite answer. Anyone got the AD823ANZ and LME49720HA duals to compare especially in the treble region. I already have the AD823ANZ, but am using stock dual opamps (NE5532) on Gustard H10. I got V5 singles put in.  I would like some more sparkle/air/energy in the treble region. Will 49720 do or is there another affordable op amp better?


----------



## DarkZenith

willowbrook said:


> This probably has been mentioned somewhere, but I can't find any definite answer. Anyone got the AD823ANZ and LME49720HA duals to compare especially in the treble region. I already have the AD823ANZ, but am using stock dual opamps (NE5532) on Gustard H10. I got V5 singles put in.  I would like some more sparkle/air/energy in the treble region. Will 49720 do or is there another affordable op amp better?


 

 JRC4556 is a classic for whoever is looking for energy and detail in the bass and treble regions imho.
 LME49720HA is the can version of LM4562 which is rather mid-centric.
 For me AD823, like a lot of "old" Analog Devices ICs, is a tad too strident.


----------



## willowbrook

darkzenith said:


> JRC4556 is a classic for whoever is looking for energy and detail in the bass and treble regions imho.
> LME49720HA is the can version of LM4562 which is rather mid-centric.
> For me AD823, like a lot of "old" Analog Devices ICs, is a tad too strident.


 
 I've never heard the JRC4556 and I keep getting all these different op amp recommendations. Is there any guide or impressions of a lot of opamps?


----------



## ScottFW

The 4556 can supply a relatively high output current and for that reason people tend to like it for driving headphone outputs. I have some on hand to try comparing in a couple of amps I have that currently use the 4580 for that purpose, but haven't gotten around to it yet. For DAC buffers driving a line out where you don't need that much current, you might go with something else. It depends what you're using it for.
  
 I'd generally agree with the older AD op-amps sounding strident, at least the couple I've tried (AD8597 and 823) dropping into CD players and DACs that originally had the 5534/5532. Definitely more treble and a harder/edgier sound that was not to my taste. Sighted/biased listening and potentially non-optimal circuit caveats apply.
  
 Nwavguy's blog (google it) has a lot of info on op-amp considerations and measurements.


----------



## DarkZenith

willowbrook said:


> I've never heard the JRC4556 and I keep getting all these different op amp recommendations. Is there any guide or impressions of a lot of opamps?


 

 Oldies but goldies :
 --- the great majkel's show : http://www.head-fi.org/t/243642/best-sounding-cheep-op-amp-for-cmoys-opa2227-opa2228-ad8066-other#post_3032335 (and some other posts from the same here on HF) ;
 --- "Chiarra Grand Op Amp Test" on Rock Grotto : http://www.rock-grotto.co.uk/opamp.htm ;
 --- "Notes on Audio Op-Amps" on TagentSoft (regularly revised) : http://tangentsoft.net/audio/opamps.html.


----------



## Mad Max

willowbrook said:


> I've never heard the JRC4556 and I keep getting all these different op amp recommendations. Is there any guide or impressions of a lot of opamps?


 
  
 I highly recommend that you go for ADA4610 instead of 4556 if you can.  4556 is nothing special in sound, you won't miss out on anything.
  
 This thread is littered with impressions.  You may find a few in threads concerning iBasso equipment, but this thread is the main repository here on Head-fi, if I'm not mistaken.
  
  
  


scottfw said:


> The 4556 can supply a relatively high output current and for that reason people tend to like it for driving headphone outputs. I have some on hand to try comparing in a couple of amps I have that currently use the 4580 for that purpose, but haven't gotten around to it yet. For DAC buffers driving a line out where you don't need that much current, you might go with something else. It depends what you're using it for.
> ...


 
  
 Bass and soundstaging are noticeably better with more output current, in my opinion.  Synthesizers and similar equipment typically use 4580 or 4556 for whatever their (likely) non-audiophool reasons, so more output current is preferred anyway.


----------



## pelopidas

I think it is important to look at the entire audio chain. In your DAC you want to have the best (whatever your preference, ie clarity, bass, ss) opamps in the I/V stage. This is amplifying the signal from the DAC from small voltages to larger voltages (line out) and the opamp that preserves and digs out the most information is usually the best. The buffer usually is just a current follower isolating the IV from the load.
 If you are going from the DAC to a headphone amp, the buffer in the DAC does not need to have a high current rating since it is going into anywhere from 5k to 50k input impedance. Only the voltage swings are passing through and not really any appreciable current.
 So the buffer position in the DAC should be based on what is as transparent or pleasing as possible and not on current.
 If you have a headphone amp that is more than a cmoy then you need to choose the I/V section again on what provides most clarity (or whatever your standard is) and then the buffer choice becomes important.
 I have experimented quite a bit here with opamps in the buffer slot and what becomes apparent is that opamps are not great buffers.
  
 If you look at the average tech sheet for opamps they usually say that they can drive 600 ohm loads with this and that distortion rate.
 The lower the impedance is the harder the opamp has to work. It is much like putting tractor tires on a BMW. It can drive but not with the usual alacrity.
 Also, the opamp circuit is more complex than it needs to be for a buffer and that is why there are so many sonic differences between them. They amplify, they invert, they correct.. and then we want them to drive a headphone too.
 The best buffer I have found for the buffer position in my headphone amp is an actual buffer. LME49600 does not do anything except add 250mw of current to that beautifully pristine and detailed signal coming from the Burson V5.
  
 The buffer does not have a high output impedance and does not need an extra output resistor to protect it from becoming unstable either. 
  
 Regular opamps seriously flavor the headphone buffer position. One of my favorite opamps is the current feedback LME49713HA which sounds so detailed and sweet in I/V (definitely not a drop in replacement. needs its own circuit) but when used as a buffer it just strips all the magic that the Burson V5 are offering and places its own flavor on everything. The LME49600 in comparison just passes the sound along without any real flavoring of the sound.
  
 Just my theory based on experience.


----------



## zilch0md

pelopidas said:


> Spoiler: Warning: Spoiler!
> 
> 
> 
> ...


 
  
 Just some seriously valuable commentary!  Thank you!


----------



## proid

mad max said:


> I highly recommend that you go for ADA4610 instead of 4556 if you can.  4556 is nothing special in sound, you won't miss out on anything.
> 
> This thread is littered with impressions.  You may find a few in threads concerning iBasso equipment, but this thread is the main repository here on Head-fi, if I'm not mistaken.
> 
> ...


 
  
 Do you mean ADA4610 is better then 4556 as a current buffer or voltage gain stage?


----------



## RamGuy

Just installed 2x LME49990 as low filters, 4x LME49990 as IV's and 2x LT1057ACN8 as buffers on my Essence One and it all works. But trying to run 2x dual LT1057ACN8 using dual adapter is not working, any reason why that is not working?


----------



## leeperry

humm, 4627-1B sounds pretty dang amazing as 9018K2M differential amp


----------



## zilch0md

ramguy said:


> Just installed 2x LME49990 as low filters, 4x LME49990 as IV's and 2x LT1057ACN8 as buffers on my Essence One and it all works. But trying to run 2x dual LT1057ACN8 using dual adapter is not working, any reason why that is not working?


 
  
 To my understanding, "dual adapters" are designed for mounting two singles where a dual is meant to go, effectively reducing the 16 pins of two single op-amps down to 8 pins for use in a DIP8 socket meant for a dual.  
  
 You say you're using "2x dual LT1057ACN8."  
  
 The LT1057 is indeed a dual,not a single, so I would think it does't need a "dual adapter."   Try plugging the LT1057s directly into the DIP8 sockets - without the adapters.


----------



## audiojun

I am in Que for the multibit upgrade for my bifrost and upgrading from the bifrost uber. I know the multibit loses the discrete analog stage and in place schiit used an op amp. 

Could I use the burson supreme sound v5 to replace the op amp in the multibit? I am asking just to be safe since I don't have much diy knowledge or done any op-amp rolling.

Edit I just realized with the op amp I wouldn't be able to put the case back unless it goes sideways with an adapter.


----------



## Mad Max

audiojun said:


> I am in Que for the multibit upgrade for my bifrost and upgrading from the bifrost uber. I know the multibit loses the discrete analog stage and in place schiit used an op amp.
> 
> Could I use the burson supreme sound v5 to replace the op amp in the multibit? I am asking just to be safe since I don't have much diy knowledge or done any op-amp rolling.
> 
> Edit I just realized with the op amp I wouldn't be able to put the case back unless it goes sideways with an adapter.


 
  
 And there are no sockets.  Hooking up a Burson opamp is still possible, not sure I would recommend that to a beginner.  Plus, you should figure out first just what those soic8 opamps are doing exactly in the circuit or you could be wasting your time trying to "upgrade" them.  U18 looks like it might be a DC servo, you won't gain any change in sound there if you replace it with anything at all as it is "out of the audio path", in a way.


----------



## FritzS

Which experience have you between
 LT1057ACN8 vs. AD823 vs. LME49720HA
 My HA Solo are delivered with AD823, now I use LME49720HA.
 Some posted here about LT1057ACN8 (an JFET)
 LME49720HA sounds a bit to high (bright) for me now.
  
 Needs LT1057ACN8 a little little cap 10 ... 33 pF in NFB too?
  
 My experience about BJT vs. FET/JFET input stage - FET/JFET sound a bit more pleasant for my ears.
 The same I adept in my WNA MKII HA - original LM6171, now OPA627 - it was a long way zu OPA627  
	

	
	
		
		

		
		
	


	



 http://rockgrotto.proboards.com/thread/8052
 http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit
 http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit/750
  
 I had used two LT1056 (the similar single version of LT1057) with very good experience in my WNA MKII too.
  
 PS: LT1057ACN8 is on the way to me.


----------



## mrhizzo

Anyone know where can I buy the MUSES02 and the OPA627BM/SM for the DAP Venturecraft Valoq? And if is just buy and install or need something more (adapter or specific specs)?


Thanks!


----------



## kahei036

mrhizzo said:


> Anyone know where can I buy the MUSES02 and the OPA627BM/SM for the DAP Venturecraft Valoq? And if is just buy and install or need something more (adapter or specific specs)?
> 
> 
> Thanks!


 
 Mouser should have them. MUSES02 is a dual opamp while opa 627 is a mono one. You need to know what your DAP uses (either a dual or mono) before swap the opamp in.


----------



## mrhizzo

I don't know if this can help, but this is the Opamp for Valoq:

http://www.head-fi.org/t/788756/lightbox/post/12341039/id/1567568/user/390018

And here some pics from the adapter:

http://www.head-fi.org/t/788756/lightbox/position/68


Thank you.


----------



## WilliamLeonhart

Hullo fellow head-fiers. This is my first time in the thread and I would like to ask if anyone has directly compare the MUSES 8820 vs the MUSES 8920? I'm currently using the Little Dot I+, which is a hybrid and also makes it a hassle to switch opamp. Had my first try with both of them today and while they're both very different from the dirt-cheap OPA2107 that I have (sharper treble, less soupy bass), I have not been able to tell the difference between the 2 (I have very short sonic memory). If anyone has both of them, can you please compare between the 8820 and the 8920 for me?
  
 Thanks a bunch!


----------



## leeperry

been rolling all the latest usual suspects and at the end of the day nothing does mids like OPA602BP to my ears, surely it must be used as a final buffer coz it's no resolution king but Morricone truly sounds magical through this little chip(and yes I even tried OPA602CM)


----------



## FritzS

leeperry said:


> been rolling all the latest usual suspects and at the end of the day nothing does mids like OPA602BP to my ears, surely it must be used as a final buffer coz it's no resolution king but Morricone truly sounds magical through this little chip(and yes I even tried OPA602CM)


 

 I had used OPA602AP for a long time in my WNA MKII headphone amp,  now I use OPA627AP(BP) with a little bit more over all performance.
 Both OPA602AP and now OPA627AP(BP) are a bit better than all other I had used - LM6171, AD843, LME49710, AD847, LT1056, LT1022, TLE2071, OPA134 
 All OPAs are in DIP8 case.
  
 Offtopic: Did anyone know about a good follower for the non-polar BlackGate NX 1000 µF 25V electrolytic caps?
 Are Nichicon ES a good substitute? I found a non-polar 1000µF 25V at Percyaudio.
 Or other non-polar too?
 https://en.wikipedia.org/wiki/Black_Gate_%28capacitor%29
 http://www.percyaudio.com/Catalog.pdf


----------



## palermo

Tried to modif my alo island, agian  muses8820 as lpf, follow by opa627au as voltage gain. I love how it sounds, a bit mid centric, singer stand closer to me with maintain smoothness and clarity, especialy at mid-high region. Something that never done good before. I've tried AD823, LT1361, LME49720MA as lpf with the same 627 being there.
I thought muses8820 has a neutral signature with no bump any freq spectrum.


----------



## SpudHarris

leeperry said:


> been rolling all the latest usual suspects and at the end of the day nothing does mids like OPA602BP to my ears, surely it must be used as a final buffer coz it's no resolution king but Morricone truly sounds magical through this little chip(and yes I even tried OPA602CM)




I'm with you there. The 602BP is one of my top 5... As you know, I also invested in the 602CM and to my ears it was colder or brittle in comparison. Have you had chance to try the Burson V5 yet?


----------



## WilliamLeonhart

williamleonhart said:


> Hullo fellow head-fiers. This is my first time in the thread and I would like to ask if anyone has directly compare the MUSES 8820 vs the MUSES 8920? I'm currently using the Little Dot I+, which is a hybrid and also makes it a hassle to switch opamp. Had my first try with both of them today and while they're both very different from the dirt-cheap OPA2107 that I have (sharper treble, less soupy bass), I have not been able to tell the difference between the 2 (I have very short sonic memory). If anyone has both of them, can you please compare between the 8820 and the 8920 for me?
> 
> Thanks a bunch!


 
 Hi, can anyone offer me your opinion?


----------



## willowbrook

williamleonhart said:


> Hi, can anyone offer me your opinion?



Have you searched through ld 1+ forum?


----------



## Mad Max

Anyone tried this one yet?
 http://www.ebay.com/itm/251471555181
  
 Looks like a little alien spaceship that you plug into your opamp sockets.


----------



## proid

williamleonhart said:


> Hi, can anyone offer me your opinion?


 
 The 8820 soundstage is wider but the 8920 ss is deeper, the 8820 sounds a bit more clear and balance, 8920 sounds darker, and smoother, more analog like. I prefer the 8920 to the 8820.
 Btw, i'm from Vn to ))


----------



## afshin

hi  
  
 8920 is a jfet  and 8820 is a bipolar ... for after dac input impedance very important ... jfet have higher impedance  ... if you want more dynamic and killer piezo-nois (piezoelectric effect) you must use film capacitor without ceramic cap for bypass PSU on chip ... near chip . mondurf silver oil can help for more and more dynamic like as analog and live sound ... I think  0.47 or 1 uf is enough and not needed smallest cap  . Try to use only one capacitor  .... without  bypass capacitor smaller. if you don't have mondurf  you can use  wima or ero  and other film (mkp) cap. 
  
 thanks .afshin


----------



## leeperry

anyone knows where to get those Class A adapters? http://www.head-fi.org/t/592367/matrix-m-stage-over-heating-with-burr-brown-opa637ap-with-class-a-biasing-mod#post_8087518
  
 Does OPA602BP benefit from this wild trick?


----------



## Cjuried

Have you tried LM4562 and/or OPA2604 Op amps in your signal path? IMO great sounding chips.
  
 Sincerely,   
   
 Chris Juried  
 Audio Engineering Society (AES) Member  
 InfoComm-Recognized AV Technologist
http://www.JuriedEngineering.com (Juried Engineering, LLC.)
http://www.TubeEquipment.com (Tube Equipment Corporation)
http://www.HistoryOfRecording.com (History of Recording)


----------



## Cjuried

proid said:


> The 8820 soundstage is wider but the 8920 ss is deeper, the 8820 sounds a bit more clear and balance, 8920 sounds darker, and smoother, more analog like. I prefer the 8920 to the 8820.
> Btw, i'm from Vn to ))


 
 After reading through the datasheet on the Muses8920 http://www.njr.com/semicon/PDF/MUSES8920_E.pdf I thought it would be worthwhile to give a few a try. Will post my findings after a few critical listening sessions.
  
  
 Sincerely,   
   
 Chris Juried  
 Audio Engineering Society (AES) Member  
 InfoComm-Recognized AV Technologist
http://www.JuriedEngineering.com (Juried Engineering, LLC.)
http://www.TubeEquipment.com (Tube Equipment Corporation)
http://www.HistoryOfRecording.com (History of Recording)


----------



## sledgeharvy

cjuried said:


> After reading through the datasheet on the Muses8920 http://www.njr.com/semicon/PDF/MUSES8920_E.pdf I thought it would be worthwhile to give a few a try. Will post my findings after a few critical listening sessions.
> 
> 
> Sincerely,
> ...




 I want to buy the Muses 8832.. I already know that I love the Muses 02 and Muses 8920.. It would be interesting to see what the 8832 sounds like in comparison.


----------



## afshin

yes... muses 8920 & opa2604 is wonderful sound ... for after D/A great ... don't forget only use film cap and break-in 300 hurs ...


----------



## bpecsek

I am trying to come to term with this biasing.
  
 Do we need CCS for both channels or one would do?
  
 In my phono stage the V- is common for both dual op amps therefor 4 single op amps are basically fed from the same V- rail.
 Doesn't injecting biasing current into the V- rail from any of the channels of any op amps output through a jFET cascode would feed all the op amps in the circuit?
  
 Thanks,
 Bela


----------



## Avro_Arrow

bpecsek said:


> I am trying to come to term with this biasing.
> 
> 
> 
> ...


 

 No, it doesn't work like that. You have to bias each op-amp output that you want to have in class A. Your not injecting bias into the V- rail, your drawn a small current from the output to the V- rail.
 Some op-amp benefit more from this than others, your mileage may vary.


----------



## FritzS

Now I was snoopy and ordered a pair of the new Burson Supreme Sound Opamp V5 S for my headphone amp WNA MKII.
 Before I used OPA627 (after a lot of others) with best performance.
 First short hearing test, my feeling the Supreme Sound Opamp V5 S surpassing the OPA627 in details of music. 
 In Ray-Brown-Summerwinds - Li'l darling (tr. 3) I hear each hair of the brushes more than with other OPAs.

 Its hard to compare them, I don't have two ident WNA MKII, so I need to swap the OPAs for comparing.
 The headphone I use for comparing is the AKG K812 Pro.
  
 More about come later.
 Next days I will spend more time for comparing.
  
 About Burson Supreme Sound Opamp V5 S
 http://www.ssaudio.com.au/products/supreme-sound-opamp-v5/
 http://www.bursonaudio.com/products/supreme-sound-opamp-v5/
  
 About WNA MKII
 http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit
 http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit/750


----------



## Mad Max

Black Gates!?


----------



## FritzS

mad max said:


> Black Gates!?


 
  
 Yes - the red cylinders are Jelmax H.P Black Gate NX 1000 uF 25V, buy'd from  Michael Percy Audio
 http://www.percyaudio.com/

 But they are out of production and out of stock 
	

	
	
		
		

		
			





 
  
 I think, the Burson Supreme Sound Opamp V5 (single or dual) are a very good option to replace OPAs.
 The only drawback, it must be place enough.
 I must use an additional DIP socket between.
  
 ​But it gives some hints about fitting, extension kits
 http://www.ssaudio.com.au/category/diy_audio_project/
 http://www.bursonaudio.com/products/supreme-sound-opamp-v5/
  
 A Burson Supreme Sound Opamp V5 instead of an SMD OPA:
 https://www.youtube.com/watch?v=j6s88jANfCw&feature=youtu.be


----------



## cas33

Is there a reason why people don't pair muse 01 and muse 02 together in a 2 slot I / V configuration? Do Jfet and Bjt compromise each other?


----------



## leeperry

cas33 said:


> Is there a reason why people don't pair muse 01 and muse 02 together in a 2 slot I / V configuration?


 
  
 lego bricks these are not.


----------



## KopaZ

Q: are there any opamps with even more (prohibitive) price tag than muses?
 I've been using muses02 with my hd800 on e12diy, but i wanna try something new.


----------



## WilliamLeonhart

Try the Burson v5. It arrived at my house a few days ago but I'm not home yet to try it. My brother says it's more analog sounding than the muses02 I have on the LD I+, but still very "premium" indeed.


----------



## zilch0md

This thread is almost seven years old, yet it seems (from searching) this will be the first post mentioning the Sparkos discrete op-amps.
  
 Here are some first impressions:
  
 http://www.head-fi.org/t/735828/gustard-h10-high-current-discrete-class-a-output-stage-headphone-amplifier/5040
  
 Mike


----------



## FritzS

williamleonhart said:


> Try the Burson v5. It arrived at my house a few days ago but I'm not home yet to try it. My brother says it's more analog sounding than the muses02 I have on the LD I+, but still very "premium" indeed.


 

 After some weeks of testing, the Burson Supreme Sound Opamp V5 is a very good choice indeed.
  
 Burson Supreme Sound Opamp V5 is one of the best I ever heard.


----------



## Lohb

fritzs said:


> After some weeks of testing, the Burson Supreme Sound Opamp V5 is a very good choice indeed.
> 
> Burson Supreme Sound Opamp V5 is one of the best I ever heard.


 

 Nice, I just got the small 4x single V5i for an iBasso PB2.
  
 Looking forward to testing them out asap.


----------



## Renfield1217

zilch0md said:


> This thread is almost seven years old, yet it seems (from searching) this will be the first post mentioning the Sparkos discrete op-amps.
> 
> Here are some first impressions:
> 
> ...


----------



## Renfield1217

kopaz said:


> Q: are there any opamps with even more (prohibitive) price tag than muses?
> I've been using muses02 with my hd800 on e12diy, but i wanna try something new.


 
 Any discrete opamp will cost more than a monolithic opamp. look up Sparkos or Bursons.


----------



## KopaZ

renfield1217 said:


> Any discrete opamp will cost more than a monolithic opamp. look up Sparkos or Bursons.




Do you think SS3601/02 would fit into the e12 diy?
I think I'll have to do measurements..
Or, did anybody managed to fit those into e12diy?


----------



## scruffy1

i have now had a mere two days of using the burson v5i
  
 it replaced a dual opa627 in the buffer position on my asus xonar hdav1.3, that was initially occupied by the stock supplied (LM)4562NA
  
 having decided in short order that the opa627 was an improvement on the 4562na i never changed it out in half a decade because it seemed clear to me that opa627 was better at "tight" bass and general all round reproduction
  
 until wednesday afternoon...  when i discovered how the burson v5i compares
  
 in a word : better
 in more words : n(much) better
  
 the only negative thing i can say is that there is a bit of a squeeze to get it to occupy the buffer socket on the hdav, and ttbomk the stx shares almost identical architecture, so might also need a little encouragement to seat it by gently easing apart the surrounding components
  
 my initial listening was via my pair of venerable but very well maintained klipsch promedia ultra 2.0, to a very large and diverse range of flacs using foobar
  
 in the two days since i got started, the first afternoon ended after 9 hours of almost solid engagement with music, something that would previously have been too fatigue inducing to manage, and it was as if the music collection had been invigorated by some act of aural magic
  
 the sound stage spread out such that every so often a subtle cowbell or rim shot would appear way too far off to one side to believe it wasn't coming from elsewhere - i actually muted the sound on one occasion to prove to myself a percussion hit wasn't something tapping the outside wall a metre to my left
  
 every instrument was precisely placed, and exquisitely nuanced, but moreso there was absolutely no harshness to the sound even with tracks i previously used to think were too shrill; and it wasn't like the edges had been softened, as the attack and fade were much crisper in the right parts, but the sustain lingered beautifully where it belonged
  
 i struggle to pull the right word to describe the effect, but the most compelling part was that everything is just so much "cleaner" but like it had been lovingly washed by a perfect shower of gentle spring rain rather than scrubbed with a surgical prep; gorgeous is not a precise descriptor i guess, but i lack the audiophile vocabulary to sound like a professional critic
  
 suffice to say, i have had my jaw drop on several occasions, listening to old favourites in a completely surreal clarity... there's stuff there i never heard before, even on the diamond 10's in the living room, and even though i am quite aware that it's not a/b testing, playing the same source in the living room to the wharfedales via a nad d3020 sounded gratingly poor by comparison
  
  
 that was me done for... although it took me another day of listening (thursday being a day off) before i could disengage after work today to do the swap i knew was inevitable
  
 so, same hdav and v5i into the htpc, using the same flacs, but this time ported via the nad d3020 (which is a dac/ class d hybrid), but using the analogue out from the hdav in place of the usb from the htpc... if i could manage to compare them a/b i would, except swapping feed out on the htpc and source on the nad simultaneously is nigh on impossible
  
 downstream from the nad are a pair of wharfedale diamond 10.1's on bespoke stands, and a 10.gx (10" active sub)
  
 yes, i know about observer bias and yada yada, but this isn't a science experiment, it's what i noticed having recognised quite clearly that the klipsch were outperforming the diamonds using the nad's integrated dac
  
  
 long story short = wow ! !! !!!
  
 i confess that i can't state that the response isn't at least in part due to the better dac qualities of the hdav, but having swapped a xonar d2 back into my desktop for the klipsch, they have immediately become more muddy (albeit still very pleasant), but my ears rebelled after only a few quiet acoustic songs, having been perfectly blissed out for most of my waking hours in the last 2 days, and mostly on those same speakers but with the v5i in play
  
 meanwhile out in the living room, song after song revealed hitherto unknown detail, and a sound stage way wider than the placement - i don't get how that can even happen, but with eyes shut there are sounds that are not between the speakers
  
 the bass is tight and dynamic, the vocals are authentic, and percussion is beautiful; guitars / sax / violin / tuba / harmonica / etc... all achingly beautiful
  
 i quite simply can't believe the polish this tiny device has applied to my music collection... i thought the $14aud i spent on the opa627 was a great investment 5 years ago, and indeed it has been
  
 but i would encourage anyone with curiosity and intact hearing to spend $40us to experience this for themselves, because no way my ramblings after two days of being possessed by music can adequately describe the epiphany this modification has provided me
  
 you have nothing to lose...  except perhaps several days of your life once you start listening and can't stop 
	

	
	
		
		

		
		
	


	



  
  
 that happened to me


----------



## zilch0md

> Originally Posted by *scruffy1* /img/forum/go_quote.gif
> 
> [snip]
> 
> ...


 
  
 Thanks very much for your well-expressed opinion!


----------



## canthearyou

zilch0md said:


> This thread is almost seven years old, yet it seems (from searching) this will be the first post mentioning the Sparkos discrete op-amps.
> 
> Here are some first impressions:
> 
> ...




I also posted in the Matrix HPA3-B and Gustard thread over 20 days ago about the Sparkos.


----------



## FritzS

scruffy1 said:


> i have now had a mere two days of using the burson v5i
> 
> it replaced a dual opa627 in the buffer position on my asus xonar hdav1.3, that was initially occupied by the stock supplied (LM)4562NA
> 
> ...


 
  
 With AKG K812 headphone, WNA MKII headphone amp, Marantz SA7001 KI CD/SACD player.
  
 SACD Tracks - Allan Taylor, Leaving At Dawn, Stockfisch
  
 Tracks 9, 10, 11, 12
  
 Comparing OPA627 vs. V5
 OPA 627, a little bit warmer
 V5, a little bit more neutral, clearer.
  
 In the WNA MKII headphone amp running all stages in Class A. I had compared them with Violectric HPA281 and SPL Phontor 2 without significant differences (with using OPA627). I think with V5 the differences are smaller.
 http://violectric-usa.com/headphone-amplifiers/hpa-v281
 https://spl.info/de/produkte/kopfhoererverstaerker/phonitor-2/uebersicht.html


----------



## zilch0md

canthearyou said:


> I also posted in the Matrix HPA3-B and Gustard thread over 20 days ago about the Sparkos.


 
  
 It's a wonder more people here on Head-Fi haven't tried it, but the price is higher than the Burson V5, so that's a showstopper for some people.  
  
 Then again, I paid $150 + shipping for a pair of NJR Muses 02, ordered from mouser.com, to avoid getting counterfeits.
  
 When you compare the material construction of the Sparkos SS3602 to the Muses02, it's the Muses 02 that's way overpriced (and not at all competitive in terms of sound quality). 
  





  
*This IC op-amp costs $75.00 (if you want to avoid counterfeit).*
  
 Update:  I paid $75.00 each for this IC op-amp in February 2014, at Mouser.com, but *they can* *currently be had for $46.25.*
  
  

  
*This discrete op-amp only costs $79.80.   (A much better value.)*


----------



## Mad Max

So the Sparkos sounds better, you feel?


----------



## Lohb

scruffy1 said:


> in a word : better
> in more words : n(much) better
> 
> the only negative thing i can say is that there is a bit of a squeeze to get it to occupy the buffer socket on the hdav, and ttbomk the stx shares almost identical architecture, so might also need a little encouragement to seat it by gently easing apart the surrounding components


 
 I see you had fitting issues with the silver cap EMI protector on the chip.
  
 I could not fit them easily in a Project Starlight I have a short while for testing. This is due to the small lip around what I guess is the EMI cap on them.
  
 However, from this photo it looks like the cap is removable. I'm not sure if it would have any adverse effect as most mainstream opamps and even Sparkos Muse 02 do not have this kind of metal cap.
 is it purely to protect the chips and should be removed on installation ? @Burson Audio
 I'm unsure from a user perspective. I did not want to wedge it off, until mine were too tight in the hybrid tube amp. Next test is iBasso PB2.


----------



## zilch0md

mad max said:


> So the Sparkos sounds better, you feel?


 
  
 Hi!
  
 Some people I've read are saying the SS3602 has a rolled-off treble compared to the Burson V5 and I have to agree it's a little bit less airy, but I really think it's also a cleaner, better-defined treble - not as (annoyingly) crystalline with the HD800 as when using the Burson V5, but I wouldn't say there's any loss of detail. It's like a big fan was turned on to suck the smoke out of the air.  When the smoke is gone, you can see better.  The treble difference is impossible to detect with the LCD-2 rev.1, by the way.  I'm struggling to find the words, but let me put it this way:  The SS3602 treble isn't as rolled-off as it is simply more quiet around the real stuff, but if this has you thinking you're going to miss out on high-frequency micro-details that you can hear with the Burson V5, that's not the case. If anything, the SS3602, just cleans them up, and makes them easier to enjoy, but yes, while rolling off the treble energy, just a bit. In short, I LOVE the SS3602 treble - it sounds really natural. 
  
 I spent several hours last weekend, and again today (Saturday) swapping the V5 and SS3602, playing short segments of favorite tracks. The SS3602 upper mids are a tiny bit recessed relative to the V5, but the bass is a bit stronger (it's subtle, but noticeable) - again, very nice for the HD800.  Everything is very tightly controlled - the best bass I've heard with the HD800 - with authority and speed.  And don't worry about the vocals - they sound stunningly real.
  
 I also feel as if I'm sitting closer to the stage with the SS3602, where everything is a little more distant with the V5, so we could argue that the soundstage isn't as expansive, but I prefer that myself. Again... we're talking about op-amp differences here, not headphone differences, so please try to scale all of my observations appropriately. But...  I like the not so laid back sound of the SS3602 vs. the V5.  That's one thing I didn't like about the Burson Soloist - sitting several rows back from the stage seems to be a Burson "house" trait.
  
 Lastly...  The SS3602 for sure has more power AND dynamics than the V5.  I had to volume match them using an SPL meter and white noise file in order to make comparisons.  
  
 I'm so impressed by how the SS3602 sounds with the DT880 600 (via the iBasso PB2's TRS jack), I've sent them out to remove the stock 3-wire cable an get mini-XLR jacks installed on each side.  I can't wait to hear the DT880 600 using both sides of the SS3602 duals - more power, with balanced output.
  

  
 Mike


----------



## scruffy1

lohb said:


> I see you had fitting issues with the silver cap EMI protector on the chip.


 
  
 true that
  
 my pics and full "build" experience is here (link)
  
  
 but here is a comparison shot of the burson and the dual opa627, and even allowing for the distorted perspective you can tell it's more a square than an oblong
  
  

  
 but it fits  
	

	
	
		
		

		
		
	


	




, although obviously with a different placement ymmv
  

  
  
  
  


> Originally Posted by *Lohb* /img/forum/go_quote.gif
> 
> is it purely to protect the chips and should be removed on installation ?
> I'm unsure from a user perspective. I did not want to wedge it off, until mine were too tight in the hybrid tube amp. Next test is iBasso PB2.


 
  
 throw an email to burson and ask; they seem very receptive to mail from my experience with them
  
 although they are less keen to offer their thoughts on relative merit to alternative options, which is understandable
  


zilch0md said:


> (lots of good stuff, and...)
> 
> Lastly...  The SS3602 for sure has more power AND dynamics than the V5.  I had to volume match them using an SPL meter and white noise file in order to make comparisons.
> 
> ...


 
  
  
 too lazy for major cut 'n' paste but obliged to ponder whether i can stand discovering better than what i already have, so soon
  
 the htpc / music project was meant to be a quick improvement, not another obsession
  
 i am not sure i could stand any better bass, but i guess a 10" driver trumps earphones, and i have adjustment for crossover frequency and volume on the sub
  
  
  
 my biggest pondering at present is whether the two liberated dual opa627 would make an improvement on the hdav in the i/v slots, or if the earlier "freed" (LM)4562NA might be an option
  
  
 you people appear to have a clue... so, what ??  i would need to faff with the lounge room set up again, so it will need a bit of encouragement to make me adequately curious and dissatisfied to put in the effort
  
 there's a remix mini android pc here i have been meaning to play with instead....


----------



## zilch0md

Hi Scruffy1,
  
 A friend of mine once told me he had read an article or heard a book or whatever that left him convinced of its message:  "Too many choices leads to unhappiness". I say, "The more choices the better," but when it comes to op-amps, I'm glad I only own one piece of gear into which I can roll them.  It sounds as if you've got several pieces with which to ramp up the permutations and combinations, as multipliers of your inventory of op-amps. You almost need to create a truth matrix, so you can keep track of which combos you've tried and what you liked.  
  
 Mike


----------



## scruffy1

so i guess it boils down to : "suck it and see"
  
 it took me 5 years to swap out the opa627's, and i am loving the bursons, so i might be much older by the time i re-visit the sound card
  
  
  
 although it only took me 3 days to shuffle the deck here to pass the benefit to the best speakers, so maybe not...


----------



## Audio Addict

zilch0md said:


> Hi!
> 
> Some people I've read are saying the SS3602 has a rolled-off treble compared to the Burson V5 and I have to agree it's a little bit less airy, but I really think it's also a cleaner, better-defined treble - not as (annoyingly) crystalline with the HD800 as when using the Burson V5, but I wouldn't say there's any loss of detail. It's like a big fan was turned on to suck the smoke out of the air.  When the smoke is gone, you can see better.  The treble difference is impossible to detect with the LCD-2 rev.1, by the way.  I'm struggling to find the words, but let me put it this way:  The SS3602 treble isn't as rolled-off as it is simply more quiet around the real stuff, but if this has you thinking you're going to miss out on high-frequency micro-details that you can hear with the Burson V5, that's not the case. If anything, the SS3602, just cleans them up, and makes them easier to enjoy, but yes, while rolling off the treble energy, just a bit. In short, I LOVE the SS3602 treble - it sounds really natural.
> 
> ...


 
  
 Thanks.  I just order a pair of the single SS3601 and look forward to comparing them with the V5.


----------



## WilliamLeonhart

May I ask what Burson is it? Is this the v5 single? It looks hugely different from the dual one I've got


----------



## FritzS

I found on mouser.de
 http://www.mouser.de/new/njr/NJR-MUSES-Amplifiers/ 
 All prices could be vary!
  
 Mouser Part No: 513-MUSES02
 Manufacturer Part No: MUSES02
 Manufacturer: NJR
 Description: Audio Amplifiers Bipolar Input Dual Op Amp
 Pricing (EUR): € 46,53
  
 Mouser Part No: 513-MUSES01
 Manufacturer Part No: MUSES01
 Manufacturer: NJR
 Description: Audio Amplifiers J-FET Input Dual Op Amp
 Pricing (EUR): 46,53 €
  
 Mouser Part No: 513-MUSES8920E
 Manufacturer Part No: MUSES8920E
 Manufacturer: NJR
 Description: Audio Amplifiers J-FET Input Dual Op Amp
 Pricing (EUR): 11,77 €
  
 Mouser Part No: 513-MUSES8820E
 Manufacturer Part No: MUSES8820E
 Manufacturer: NJR
 Description: Audio Amplifiers High Quality Audio Dual Op Amp
 Pricing (EUR): 9,81 €
  
 Mouser Part No: 513-MUSES8832E
 Manufacturer Part No: MUSES8832E
 Manufacturer: NJR
 Description: Audio Amplifiers High Qual Audio Dual Op Amp 10MHz
 Pricing (EUR): 13,18 €
  
 Mouser Part No: 513-MUSES72320V-TE2
 Manufacturer Part No: MUSES72320V-TE2
 Manufacturer: NJR
 Description: Audio Amplifiers 18V Operation 2-CH Electronic Volume
 Pricing (EUR): 25,15 €


----------



## zilch0md

audio addict said:


> Thanks.  I just order a pair of the single SS3601 and look forward to comparing them with the V5.


 
  
 Yay!  I'm hoping you can justify my comments, but feel free to vilify me, instead!  LOL 
  
 It's so hard to be objective with this subjective hobby.


----------



## Lohb

williamleonhart said:


> May I ask what Burson is it? Is this the v5 single? It looks hugely different from the dual one I've got


 
 New V5i, not the previous tall red V5.


----------



## WilliamLeonhart

Is it dual or single?


----------



## zilch0md

fritzs said:


> I found on mouser.de
> http://www.mouser.de/new/njr/NJR-MUSES-Amplifiers/
> All prices could be vary!
> 
> ...


 
  
 Wow!  At http://www.mouser.com, I'm surprised to see that their price of a MUSES02 is currently only USD $46.25, purchasing fewer than 10 at a time.
  
 http://www.mouser.com/search/ProductDetail.aspx?R=0virtualkey0virtualkeyMUSES02
  
*The prices have come way down!*  
  
 In November of 2013, *they were on backorder* at all of the reputable dealers in the U.S. *I waited three months* until mouser.com had them back in stock - when I then paid $75 each, plus tax and shipping.
  
12 Nov 2013 - They were not available at any reputable U.S. dealers.
  
12 Jan 2014 - I was still waiting, rather than taking a chance on counterfeits from an eBay vendor.
  
14 Feb 2014 - I placed an order with Mouser, buying two Muses02 for $166.87, including tax and shipping.
  

  
 Supply and demand - I guess since writing my lackluster reviews of the Muses02, the word is out and they are now plentiful.


----------



## FritzS

williamleonhart said:


>





> May I ask what Burson is it? Is this the v5 single? It looks hugely different from the dual one I've got


 

 V5I-D?
*D* stands for Dual, *S* for Single
  
 To the current original SS V5 OPAs
 http://www.ssaudio.com.au/products/supreme-sound-opamp-v5
  

  
 But SS V5I are from Burson too
 http://www.bursonaudio.com/products/supreme-sound-opamp-v5i
  

  
 I think the V5 (without I) is the follower of V5I


----------



## FritzS

zilch0md said:


> Supply and demand - I guess since writing my lackluster reviews of the Muses02, the word is out and they are now plentiful.


 
  
 Another source:
 http://www.digikey.com/us/en/ph/njr/muses0102.html
 http://www.digikey.com/product-search/en?keywords=Muses01
 http://www.digikey.com/product-search/en?keywords=Muses02
  
 For other special parts
 http://www.percyaudio.com/
 http://www.percyaudio.com/Catalog.pdf


----------



## WilliamLeonhart

I've checked their website and the v5i is much cheaper, at $39 for a dual unit only. Perhaps it's a special version of the v5 with something cut to reduce the price?


----------



## Audio Addict

williamleonhart said:


> I've checked their website and the v5i is much cheaper, at $39 for a dual unit only. Perhaps it's a special version of the v5 with something cut to reduce the price?




The new V5i is an IC based version of the v5. It is not at the level of the v5, which is discrete. Hence the lower price. I was going to try and compare them with the v5, which I use, and was there was no reason to as the v5 is superior.


----------



## Audio Addict

zilch0md said:


> Yay!  I'm hoping you can justify my comments, but feel free to vilify me, instead!  LOL
> 
> It's so hard to be objective with this subjective hobby.




I have the Lycan, whose purpose was to roll opamps, so I have to.


----------



## FritzS

williamleonhart said:


> I've checked their website and the v5i is much cheaper, at $39 for a dual unit only. Perhaps it's a special version of the v5 with something cut to reduce the price?


 

 No! You should read the comments on Bursons web-pages
  
 http://www.bursonaudio.com/products/supreme-sound-opamp-v5i
  Quote of V5I description: 





> A Hybrid Audio Opamp with SSV5 DNA The inception of our latest product originated as a result of our partnership with a leading microchip foundry.  Together we have created an integrated version of our V5 FET circuitry. In order to overcome many of the inherent limitations associated with ICs, we have externalized parts of its circuitry and completed those sections with high quality discrete components. *The newly developed Burson V5i is a hybrid audio opamp, which is both partially IC and discrete.  It bears the sonic signature of its bigger brother, the V5 discrete opamp, considered by many as the reference in audio application.*


 
 

*V5 is a full discrete, V5I is a hybrid (using IC and discrete elements) audio amp!*


----------



## scruffy1

i have more observations to share :
  
 encouraged by this thread, and because no-one seems to have recorded the swaps per my google-fu, i rolled the liberated opa627 and then their forebears in the buffer socket, (LM)4562NA, into the i/v sockets that have a default JRC 2114D's
  
 spec sheets show that candidates both have much faster slew rates (whatever that tells me, but i wanted to hear what it meant), with the 627 per their spec pdf rated at a 55V/Âµs (typ) and GBP of 16; the (LM)4562NA is also "very quick with a slew rate of +/- 20V/Âµs (typ) and a GBP of 55Mhz", or so i am told here : 
 http://www.guru3d.com/articles-pages/asus-xonar-essence-st-deluxe-review,9.html
  
 it took two songs with the opa627 to shake my head
  
 the harshness that i wasn't missing at all after it had been banished by the xonar and v5i had snuck back - it sounded not entirely unlike the dac in the nad d3020, but not quite as grating as my now receding memory of it could recall
  
 the bass was more prominent, but like i said, after two songs, my eardrums felt "itchy" - as a medical person i know that's not possible, but having spent the last > 4 days listening to the new arrangement of components at some rather impressive volume, my ears neither rang post session, nor felt like they needed a rest
  
 two songs with the opa627's in the i/v, and the v5i in the buffer and i didn't want to listen to any more
  
 ah well...  onto the 4652na's
  
 this is a bit more difficult to judge; i am well aware that after > 50 hours of rather concentrated (and concentrating) listening i have undoubtedly become accustomed to the sound of the default i/v jrc2114d's with the burson v5i, and i really enjoy the synergy
  
 the 4652 in the i/v are still good, but different, in a way that i find less appealing
  
 the sound stage is much less distinct in placement, but overall the detail is good, albeit biased in a different way
  
 the brass is less "sharp" and somewhat more laid back in the mix, the whole ambience is perhaps warmer but not as precise
  
 i did note that the resonance on the infectious guitar break in kotoya's "vami duwe" had some harmonic edge to it that was spectacular, but whilst that's great, i can't be content trading the whole reproduction for a few notes on one instrument
  
 if you like SS3602 (zilch0mod), i suspect their signature would be closer to that albeit not the clarity - headphones seem to demand a different "sound" to a 2.1 system sporting a 10" bass driver
  
 i could only last 3 songs before i was keen to re-test the jrc2114 back in the card, and i immediately liked the result, but again, i am damned for having burnt this sound into my brain as the new "normal" in my living room
  
 the positive discovery from my little blitz is that i am not missing anything from the parts i have available to test... i've already lucked out on the best combo for my tastes on the first roll
  
 cheers !


----------



## Mad Max

4562 is nice, but needs extra PSU bypassing, usually, otherwise it can sound diffuse and rather unnatural or somehow unappealing.
  
 LME49860 is the awesome one and my favorite National chip.  One of my all-time favorite opamps, too.


----------



## Lohb

I found 4562 brittle/analytic and I only like it mixed with tubes.


----------



## Renfield1217

zilch hi,
 and you are runninSparkos right?


----------



## zilch0md

Now I'm pushing the DT880 600-Ohm with balanced output from the PB2 (with both sides of the two Sparkos Labs SS3602 Duals). It's almost an injustice to call the DT880 600 a poor man's HD800. It sounds so much better with twice the power from the PB2.  
  
 http://www.head-fi.org/t/633511/pictures-of-your-portable-rig-part-xvi/20250#post_12650499


----------



## WilliamLeonhart

Here's a big question: Can you name all the (somewhat) famous headphone amps that use opamp? So far I've know the cmoyBB, Little Dot I+, some soundcards (most famous of which is perhaps the ASUS Xonar) and the xDuoo xd05.


----------



## WilliamLeonhart

fritzs said:


> No! You should read the comments on Bursons web-pages
> 
> http://www.bursonaudio.com/products/supreme-sound-opamp-v5i
> 
> ...


 
 Thanks for the clarification. I was too lazy lol


----------



## Unclewall

I wonder what op amp  is used in *V5I*


----------



## Lohb

unclewall said:


> I wonder what op amp  is used in *V5I*


 

 it is proprietary, not off-the-shelf that they can just drop inside.


----------



## KopaZ

Aaaaaaaand my SS3602 sparko opamp is stuck on USPS blackhole at kearny NJ.

thank you ebay sellers using godforsaken garbage USPS first class/standard package service.


----------



## Unclewall

lohb said:


> it is proprietary, not off-the-shelf that they can just drop inside.



I would not think they would order enough to custom design IC chip and setup production line probably more like order some with no markings


----------



## Mad Max

kopaz said:


> Aaaaaaaand my SS3602 sparko opamp is stuck on USPS blackhole at kearny NJ.
> 
> thank you ebay sellers using godforsaken garbage USPS first class/standard package service.


 
  
 You're extremely unlucky.
  
 USPS 1st class has only given me trouble about three or four times in eight years and a few hundred parcels (buying/selling), so I feel their service is pretty good overall.


----------



## zilch0md

kopaz said:


> Aaaaaaaand my SS3602 sparko opamp is stuck on USPS blackhole at kearny NJ.
> 
> thank you ebay sellers using godforsaken garbage USPS first class/standard package service.


 
  
 That's weird.  The same thing happened to me.  Tracking info showed it went half-way across the country very quickly to reach a local USPS distribution center that's only 10 miles from my house - where it sat still, going nowhere for about three days, then it took a whole day to make it to my local post office and I got it the next day.  Sheesh!
  
 I have a theory: The USPS is so busy delivering Amazon packages that are handed off to them from the UPS, that they couldn't care less about their direct clients. They've got a big fat contract with Amazon/UPS that takes precedent over all parcels that are not shipped by Priority or Express Mail. 
  
 Zzzzzzzzzz....


----------



## Audio Addict

zilch0md said:


> That's weird.  The same thing happened to me.  Tracking info showed it went half-way across the country very quickly to reach a local USPS distribution center that's only 10 miles from my house - where it sat still, going nowhere for about three days, then it took a whole day to make it to my local post office and I got it the next day.  Sheesh!
> 
> I have a theory: The USPS is so busy delivering Amazon packages that are handed off to them from the UPS, that they couldn't care less about their direct clients. They've got a big fat contract with Amazon/UPS that takes precedent over all parcels that are not shipped by Priority or Express Mail.
> 
> Zzzzzzzzzz....


 
  
 Mine shipped yesterday and has departed Denver, we'll see how long it takes to get to Central IL.


----------



## WilliamLeonhart

williamleonhart said:


> Here's a big question: Can you name all the (somewhat) famous headphone amps that use opamp? So far I've know the cmoyBB, Little Dot I+, some soundcards (most famous of which is perhaps the ASUS Xonar) and the xDuoo xd05.


 
 Any one?


----------



## Audio Addict

williamleonhart said:


> Any one?


 
  
 I believe almost all of Ray Samuel Audio headphone amplifiers used various opamps versus discrete though Ray basically etched out any identifying information since he spent a lot of time finding the best for his design.  I am sure there are a lot of others.


----------



## Lohb

unclewall said:


> I would not think they would order enough to custom design IC chip and setup production line probably more like order some with no markings


 
A Hybrid Audio Opamp with SSV5 DNA *The inception of our latest product originated as a result of our partnership with a leading microchip foundry.*  Together we have created an integrated version of our V5 FET circuitry. In order to overcome many of the inherent limitations associated with ICs, we have externalized parts of its circuitry and completed those sections with high quality discrete components.


----------



## zilch0md

audio addict said:


> Mine shipped yesterday and has departed Denver, we'll see how long it takes to get to Central IL.


 
  
 In my case and with KopaZ, it quickly made the trip to our respective, local USPS distribution centers, then sat there for a couple of days, going nowhere, before finally making the last few miles to our respective local local post offices, then sat there overnight, before getting delivered to our homes. I 
  
 So it will probably get to Central IL, quickly. I'm curious as to how long it will sit still at your local USPS distribution center - as revealed by the tracking info. 
	

	
	
		
		

		
			





  
  
 Another thing that's weird about the USPS, is that if you request text message updates to your phone, the text messages run almost a full day behind the actual change in status. I suspect that just as there is a big bottleneck of first class parcels in their distribution centers, their servers are suffering a massive backlog for issuing text messages.  LOL
  
 If I let my suspicious nature run wild, I can easily imagine that these delays in handling First Class parcels are intentionally levied to "encourage" USPS customers to use their more expensive Priority Mail and Express Mail services, instead. In the end, that's perfectly OK. I like having the choice of saving money to ship things slowly and, ultimately, prices reflect what the market is willing to pay (unless the government interferes with free market supply and demand interactions.)


----------



## zilch0md

williamleonhart said:


> Any one?


 
  
 I don't know if they qualify as "famous" or even "(somewhat) famous" but one that you didn't mention (but probably already know about) is the Gustard H10, which tends to run hot enough when the lid is on the case to melt the Burson V5.  And this might not appeal to you, but I've read that Burson's Lycan is a great little amp - especially for rolling op-amps, as it's not balanced, and thus, you only have to buy half as many op-amps to test them.  Other than portables, I can't think of any other "desktop" amps that have socketed op-amps that can be easily removed, but there are probably several I just don't know about.


----------



## Audio Addict

zilch0md said:


> In my case and with KopaZ, it quickly made the trip to our respective, local USPS distribution centers, then sat there for a couple of days, going nowhere, before finally making the last few miles to our respective local local post offices, then sat there overnight, before getting delivered to our homes. I
> 
> So it will probably get to Central IL, quickly. I'm curious as to how long it will sit still at your local USPS distribution center - as revealed by the tracking info.
> 
> ...


 
  
 They arrived today as I bought 2 singles.  I just put them in.  Haven't listened but I can tell you I was shocked by the different efficiency that the Burson Audio SSA v5D I had in the Lycan.  Just put the Purist Audio Design Ultimate System Enhancer CD on for a few hours to break them in.


----------



## scruffy1

audio addict said:


> They arrived today as I bought 2 singles.  I just put them in.  Haven't listened but I can tell you I was shocked by the different efficiency that the Burson Audio SSA v5D I had in the Lycan.  Just put the Purist Audio Design Ultimate System Enhancer CD on for a few hours to break them in.


 
  
 more ? less ?? efficient


----------



## Audio Addict

scruffy1 said:


> more ? less ?? efficient




Much less efficient. With the Pulse Infinity, with the v5D and the THX00, I could actually hear out when the Pulse was at -51 but with Sparkos Labs, I had to turn it up to in the low -30s. There still is a lot of control but I had not thought about that type of difference.


----------



## scruffy1

more detail please
  
 can you perhaps specify which opamps you are comparing, and which is the "louder" ?  you obviously know which one you mean... that makes one of us


----------



## Overkill Red

Right... Not sure if it works this way, but can anyone recommend off the top of their head a clear, balanced and energetic OpAmp?


----------



## Mad Max

ADA4627-1B or ADA4610
 If it sounds unbalanced when you stick it in, it probably just needs an extra film cap across its PSU pins.  You'll need the chips mounted on adapters.


----------



## scruffy1

overkill red said:


> Right... Not sure if it works this way, but can anyone recommend off the top of their head a clear, balanced and energetic OpAmp?


 
  
 it doesn't quite work that way, but to help you :
  
 http://www.head-fi.org/t/432749/the-opamp-thread/5175#post_12642543
  
 however, that's just my opinion, so you should read the other 349 pages in this thread  (a mere 5238 posts) to give it appropriate context; but the burson v5i is doing it for me in a major way presently
  
 as a further comment, (dual) opa627 is a cheap(er) and really good place to start for the buffer position if you want to appreciate a step up from the default supplied on the stx - sounds less marvellous in the i/v slots though


----------



## Audio Addict

audio addict said:


> Much less efficient. With the Pulse Infinity, with the v5D and the THX00, I could actually hear out when the Pulse was at -51 but with Sparkos Labs, I had to turn it up to in the low -30s. There still is a lot of control but I had not thought about that type of difference.




After listening to sparkos labs S3601 pair, I put the v5D back in and the difference was not that great. I am not sure why the change is there now. 

I have seriously listened enough for any conclusions yet.


----------



## zilch0md

audio addict said:


> They arrived today as I bought 2 singles.  I just put them in.  Haven't listened but I can tell you I was shocked by the different efficiency that the Burson Audio SSA v5D I had in the Lycan.  Just put the Purist Audio Design Ultimate System Enhancer CD on for a few hours to break them in.


 
  
  


audio addict said:


> Much less efficient. With the Pulse Infinity, with the v5D and the THX00, I could actually hear out when the Pulse was at -51 but with Sparkos Labs, I had to turn it up to in the low -30s. There still is a lot of control but I had not thought about that type of difference.


 
  
  


audio addict said:


> After listening to sparkos labs S3601 pair, I put the v5D back in and the difference was not that great. I am not sure why the change is there now.
> 
> I have seriously listened enough for any conclusions yet.


 
  
  
 Just to be clear, please entertain this question:  
  
*If you were to swap the op-amps back and forth without touching the volume control, which would play more loudly in your headphones - the Burson V5 or the Sparkos?*
  
 If my interpretation of your earlier posts is correct, I'm thinking your will answer that the Burson V5 is louder - which really surprises me because I experience exactly the opposite with the V5 Duals vs. Sparkos SS3602 in my iBasso PB2.  It's a noticiable difference, true enough, but I measure a higher SPL reading between the headphone ear pads, when using the Sparkos op-amp.
  
 Maybe it's just a difference in supply voltage with your amp vs. mine.  The relationship between supply voltage and output power is almost never linear.  In other words, in terms of output power, maybe the Sparkos is a better suited to my amp, where the V5 is better suited to yours.


----------



## Audio Addict

zilch0md said:


> Just to be clear, please entertain this question:
> 
> *If you were to swap the op-amps back and forth without touching the volume control, which would play more loudly in your headphones - the Burson V5 or the Sparkos?*
> 
> ...


 
  
 I am using the Burson Audio Lycan so there may be bias build in for their  v5 discrete opamp.  Originally I thought there was a significant difference but after letting the Sparkos Lab S3601 singles play for roughly 36 hours, when I swapped the v5D back in last night, not changing anything, the difference was not nearly as noticeable.  I would say t he v5D was only slightly louder.  However, what I did notice is the Sparkos Labs seemed to have more treble than the v5D.  I don't know if any of the difference could be attributable to using 2 single S3601 and the 1 dual v5.


----------



## zilch0md

audio addict said:


> I am using the Burson Audio Lycan so there may be bias build in for their  v5 discrete opamp.  Originally I thought there was a significant difference but after letting the Sparkos Lab S3601 singles play for roughly 36 hours, when I swapped the v5D back in last night, not changing anything, the difference was not nearly as noticeable.  I would say t he v5D was only slightly louder.  However, what I did notice is the Sparkos Labs seemed to have more treble than the v5D.  I don't know if any of the difference could be attributable to using 2 single S3601 and the 1 dual v5.


 
  
 Thanks for your clarification!  I'm perfectly OK with your impressions, as we are not making an apples-to-apples comparison - different gear, not to mention different ears.
  
 In the end, as with almost all audio components, prospective buyers really have to make whatever comparisons they are considering - on their own.  There are very few audio products that have acquired a truly majority consensus of positive opinion - as with the Uptone Audio USB Regen, where even though different people hear different things across countless combinations of gear, only a tiny fraction of buyers end up returning it for having made no audible improvement that they can discern - it's something like 1 out of 500 people are disappointed, judging by what I've read, following multiple USB Regen forums.
  
 I am, nevertheless, pretty comfortable in saying I believe most people who have even a modest amount of experience rolling op-amps, having spent a lot of time critically analyzing the differences, would find either the Burson V5 series or Sparkos SS360x series discrete op-amps to stand well above any IC-based op-amp. Beyond that solid conviction, I can only say that I personally prefer the Sparkos SS3602 to the Burson V5 Dual, with my gear, my headphones, my tastes.  They stand on the podium together - so I would heartily advise anyone considering them to try both and decide for yourself. Big bucks, I know - but perhaps some other factors (dimensions, heat tolerance, supply voltage maximums, etc.) can guide you if you only want to buy one or the other and be done with it.  
  
 The Sparkos is fat but short - too fat for some applications. The Burson is skinny but tall - too tall for some applications. Which one is a better fit inside your component? The Sparkos can handle higher supply voltages, maxing out at +/- 22V vs. +/- 17V for the latest rendition of the V5.  (Higher supply voltages translate to higher output voltages delivered to your headphones - assuming you have an amp that can push the max. 22V Sparkos higher than the max. 17V Burson.) The Sparkos can handle higher operating temperatures - its PCBs are not trapped inside a foam-filled plastic case that can overheat and melt if insufficiently cooled.
  
 Back to a discussion of the audible differences - again with the disclaimer that my opinion may not translate across to anyone else's gear and tastes...  When using this chain:  
  

iPod Touch 6, streaming 44/16 from Tidal Hifi >
Oppo HA-2's ES9018K2M DAC Line Out >
A Cardas HPI interconnect cable >
iBasso PB2 portable amp, with dummy buffers instead of real op-amps in the output gain stage, such that I am only hearing the Burson or the Sparkos duals in the Input voltage gain stage > 
Balanced output with Toxic Cables _Silver Poison >_
Into either my 300-Ohm Senn HD800 or my recently acquired (I'm late to the party) 600-Ohm Beyer DT880 (modified by BTG-Audio to replace the single-ended cable with mini-XLR jacks for balanced operation with an Audeze-style balanced _Silver Poison_ cable).
  
 Having qualified the conditions in which I made my comparisons, let me add that I used a cheap SPL meter, made by Scosche, placed between the ear pads with the headphones sitting on a table, to volume match the Burson and Sparkos duals while playing a white noise file, putting marks on transparent tape that I had placed around the volume control of the amp- so that I could toggle the volume control correctly as I swapped the op-amps back and forth while playing some favorite test tracks. Even if the inexpensive Scosche meter is inaccurate when it reads 85dB, I adjusted the volume to achieve the same reading with both sets of op-amps, while playing white noise, so the actual SPL level was perfectly matched, even if not precisely at 85dB.
  
 All that said, I prefer the sound of the Sparkos for these reasons:  The treble has less of a "glow" that I believe is not really part of the recording. I don't think the Sparkos treble is so much rolled-off relative to the Burson treble, as it is just cleaner.  I hear even the faintest of low-energy treble details better surrounded by blackness with the Sparkos, where the V5 has an ever so slightly "splashy" sound.  Mind you, I find these distinctions impossible to make with less resolving headphones like my LCD-2 rev.1, with which I would only conclude that the V5 has more treble energy, but I am making the allegation that the V5's treble energy is not entirely genuine. Toss in an NOS DAC, like my Metrum Octave MkII and you might as well have replaced the HD800 or DT880 with the LCD-2 rev.1.  The NOS DAC has nowhere near the resolution of the diminutive Oppo HA-2's ES9018K2M implementation.  Again, this points to how the chain that surrounds these op-amps can mask certain aspects of their intrinsic traits.
  
 I liken the ever so slightly "splashy" treble of the Burson V5 (in my chain) to how uncontrolled, sloppy bass frequencies can be misinterpreted as having higher energy than a faster, more tightly controlled bass. The wooliness caused by longer decays create a perception of higher energy, summed across time, even though instantaneous measurements might prove them to have the same energy. For some systems and some tastes, this might actually produce a preferred sound, just as the Burson V5 treble might be preferred by some people, in their environments, vs.the, dare I say it, more "genuine" treble of the Sparkos duals. I mean, let this sink in:  I prefer the V5 treble when using any headphone I have other than the DT880 or HD800.  You could say I want to darken my too-bright HD800 and DT880 by using the Sparkos op-amps or you could say I want to brighten my too-dark LCD-2 rev.1 and I suspect my HD600 or HD650, when I still had them, by using the Burson V5 op-amps. And that's without changing anything else in the chain.  Underneath it all, I believe the Sparkos is the more accurate and transparent op-amp.  Whether or not that works for you will be determined by a lot of other variables.
  
 Varying with the resulting output power of the op-amps, depending on the supply voltage they receive, and the efficiency of your choice of headphones, if you are running really inefficient headphones, like the Beyer DT880 600-Ohm, and your amp when set to its highest gain, still leaves the headphone hungry for more power, I can attest that there is significant difference in dynamics enjoyed with the op-amp that can produce a higher volume.  Which for me, in my gear, as evidenced by the volume matching I did, lies with the Sparkos SS3602.  Bass drum kicks especially stand out with the Sparkos SS3602 driving my DT880 600, but less so with the HD800.  For the LCD-2 rev. 1, which can scale to more power all the way up to 13 Watts rms per channel into 50 Ohms (per Audeze support), the difference between the Sparkos and V5 is also noticeable, but for the DT880 600, where its inefficiency seems to be more perfectly suited to the peak output possibilities of my balanced output iBasso PB2 with either the Burson or the Sparkos duals, the Sparkos wins, doing a fantastic job of controlling the 600-Ohm headphone with greater authority. The bass texture is spectacular - better control than with the HD800 bass (not to mention having more bass energy than the HD800, but that's a feature of the DT880 whether or not the bass is tightly controlled.)  
  
 And again, for my gear and my ears, I find that the Sparkos puts me closer to the stage, where the Burson V5 pushes the whole soundstage farther away, more laid back, as if I'm seated in the 10th row.  Having owned the Burson Soloist, I can say that this kind of "house" trait for Burson.  I don't understand how it happens or how they could design for it, but if you want to feel closer to the voices and instruments, the Sparkos has an edge (as I've experienced it with my gear.)  
  
 Lastly, I'll throw in my conviction that the design and quality control of the Sparkos op-amps is in another league relative to the Burson V5. They've had to ship me four V5 duals to end up with two that were not defective on arrival. Sparkos doesn't have much representation in these forums or others, but I do know this:  I have not had to return the pair of SS3602 duals I purchased. - they run cool and have already logged easily 400 hours without any hiccups.    
  

  
 Mike


----------



## scruffy1

so, do these look like they will change the world ?
  
 https://www.kickstarter.com/projects/nura/nura-headphones-that-learn-and-adapt-to-your-uniqu


----------



## canthearyou

scruffy1 said:


> so, do these look like they will change the world ?
> 
> https://www.kickstarter.com/projects/nura/nura-headphones-that-learn-and-adapt-to-your-uniqu




They look interesting.


----------



## zilch0md

It seems as if the calibration only adjusts frequency response.  
  
 This paragraph is interesting:
  


> *Nura headphones connect to the lightning/usb port of your smartphone.* You press go, and they sweep through a bunch of tones for about 30 seconds. At the same time, they listen to the sounds your ear is making. By processing these signals it works out how well specific frequencies of sound got through to your brain. Once they know this, they sonically mould to match your ears perfectly and provide rich, balanced sound for you.


 
  
 Do these headphones have an internal DAC/amp?   (I suspect they do.)
  
 Can they only be used with iOS and Android devices?   (It seems so.)
  
 The only way they can calibrate the FR to a given listener is to perform the calibration using the same DAC/amp that will be used when later playing music. They're pulling the calibration tones out of an app on your mobile device - digitally - not as analog line out from a file played through your DAC and amp of choice.  So, these things appear to leave you stuck with using their built-in DAC and amp.
  
 But if it sounds good, fine.


----------



## scruffy1

zilch0md said:


> .
> But if it sounds good, fine.


 
  
_"It is probably the biggest innovation since Bose's loudspeakers."_ - *Andrija Nikolic, Apps Rooster *
  
 way to kill enthusiasm amongst the tech literate, much...


----------



## Mad Max

That's a good one.


----------



## KopaZ

*facepalm*
 Note to myself..
 DO CHECK BEFORE SWAPPING OPAMP OUT; god knows what will happen to circuitry when you put the opamp on reverse.
  
 I think I f-ed up tubes on my little bear B3.


----------



## scruffy1

kopaz said:


> *facepalm*
> Note to myself..
> DO CHECK BEFORE SWAPPING OPAMP OUT; god knows what will happen to circuitry when you put the opamp on reverse.
> 
> I think I f-ed up tubes on my little bear B3.


 
  
 burson's site has this to say :
  
Installation Steps *1. Make sure you have the right SS Op-Amp*
 – V5-OPA-D = dual Version Op-Amp = suitable to replace dual version chip opamps
 – V5-OPA-S = single Version Op-Amp – suitable to replace single version chip opamps
*2. Plug it in the right direction*
 Align the half moon marking on the PCB or IC socket to the half moon cut out on the SS Op-Amp enclosure (refer to photo below)
*3. Register the SS Op-Amp for a life-time of warranty*
 Only by completing this simple registration via this link (http://www.bursonaudio.com/warranty-diy/), will your SS Op-Amps be covered for life.
  
_*Please note that not following the first 2 steps above will certainly destroy the SS Op-amp, such cases will not be covered by our warranty.*_


----------



## KopaZ

scruffy1 said:


> burson's site has this to say :
> 
> Installation Steps *1. Make sure you have the right SS Op-Amp*
> – V5-OPA-D = dual Version Op-Amp = suitable to replace dual version chip opamps
> ...


 
 it didn't destroy the op-amp, it probably will if you let it burn for few more seconds though.


----------



## canthearyou

Small comparison coming soon. Sparkos Labs, Burson V5 and Burson V5i.

First impressions are the new V5i are excellent op-amps, especially for the price.


----------



## msknight

Hi Folks,
  
 Just purchased a Little Dot 1+ and am wondering about OpAmps. Have read a few pages here, but am none the wiser.
  
 Target phones are Senn 600 and DT 990 Pro ... to misquote a song... "Valves, I have a few..." music target is vocal and brass.
  
 Any suggestions please? I'm assuming, looking at circuits, that I need a single opamp.


----------



## Lohb

msknight said:


> Hi Folks,
> 
> Just purchased a Little Dot 1+ and am wondering about OpAmps. Have read a few pages here, but am none the wiser.
> 
> ...


 
  

  
 Looks like 1 dual.
  
 Burson Audio and Sparkos Labs have both released new discrete next gen. opamps.
 Either one would know the correct opamp to send.


----------



## Zulkr9

Does anybody know if these discreet op amps can be used instead of buffers like the LME49600 and the BUF634. Any ideas ?


----------



## msknight

lohb said:


> Looks like 1 dual.
> 
> Burson Audio and Sparkos Labs have both released new discrete next gen. opamps.
> Either one would know the correct opamp to send.


 
  
 Thanks.
  
 Someone advised me to give stock a try first and settle in to a few different valves and run with those before considering the opamp. I'll keep that in mind, though, and knock them up when I'm ready.
  
 I'm big on doing my research before jumping  ... gotten burned too many times already!


----------



## frogmeat69

The 1+ uses a dual op-amp.


----------



## zilch0md

zulkr9 said:


> Does anybody know if these discreet op amps can be used instead of buffers like the LME49600 and the BUF634. Any ideas ?


 
  
 I've never tried it, myself, but several guys in the Gustard H10 amp thread have used the Burson V5s as buffers.


----------



## Renfield1217

Hi Zilch0md,
  
 Yes, I have ran the Sparko SS3602 as a buffer in an Asus STXII with no probs and it sounded quite good.
  
 Ren


----------



## WilliamLeonhart

msknight said:


> Hi Folks,
> 
> Just purchased a Little Dot 1+ and am wondering about OpAmps. Have read a few pages here, but am none the wiser.
> 
> ...


 
 You need ONE opamp, but the DUAL version, like the V5 SS. I think on Vocals it'll serve you well. Of course the Sparko SS3602 is also great but I prefer my Burson for those genres you spoke of.
  
 But how well does the I+ drive your Senn 600 and DT990?


----------



## Lohb

williamleonhart said:


> You need ONE opamp, but the DUAL version, like the V5 SS. I think on Vocals it'll serve you well. Of course the Sparko SS3602 is also great but I prefer my Burson for those genres you spoke of.
> 
> But how well does the I+ drive your Senn 600 and DT990?


 

 Is the V5SS going to fit in the underside of that amp closed ? I doubt it.
 He would need V5i Dual. if Burson.


----------



## CJG888

Frankly, for high impedance cans, the Mk III would be better...


----------



## WilliamLeonhart

lohb said:


> Is the V5SS going to fit in the underside of that amp closed ? I doubt it.
> He would need V5i Dual. if Burson.


 
 No. That's why it's running "pantless" like this:
  

  
  
  
 I post these impression in the I+ thread but there's not a lot of people there so I'm posting it again here. Hope you guys won't mind 
  

_The V5 SS is really much bigger than other opamps._

_Which explains why I can't close the lower panel of my I+_
  
  

_The box that the V5 came in next to my LD._
  
 My most favorite headphones of all time: Grado SR325e. So favorite that I've sold and bought it again for 3 times (if you also count the 325is, that's 6 times). The SR325e is perhaps one of the most Grado-ish of all Grados with crunchy bass, highly energetic trebles and sweet refined mids, even though the mid-range here can be considered a bit more neutral and less forward than its siblings RS1i or SR60e.
 What would the I+ V5 brings to my 325e? First of all, with the right tube it retains all the thing I love the most about the 325 line: aggressive trebles and textured, forceful bass.
 Take my reference Metal track for example: _I Remain _by Paradise Lost. Each guitar notes rings out really nice into the soundstage, each cymbal crash or snare beat can be felt with the satisfying "crunchie" that I've come to love from the 325 line. Most beautiful and addictive of all is the distorted guitar sound: one again, it's as if you can count each layer inside the riff. Think of the words that are often used to name those Metal subgenres. "Groove", "Grind(core)", "Industrial", "Thrash" etc. The riffs on my V5 I+ 325e combo are going to turn all those lousy names into reality.
 The Burson V5 SS must play some role in bringing out the bass and the low-mid sections from my SR325e, as my old MUSES8820 reduced these to _...And Justice for All_ level. That was the reason why my GE JAN 5654W never got much love while the MUSES was driving my I+, but now with the V5 SS I can certainly enjoy the sparkly trebles and the slightly accented mids.
 On the other hand, it's quite obvious to me that the V5SS gives a smoother, more laid-back sound than the 8820. No wonder my Siemens 5654W turns out to be too smooth, too laid-back to pair with the V5 SS on my I+. These tubes practically muffle everything from _November Rain _(Guns n' Roses) to _Angels _(Within Temptation).
 It can be said that the level of smooth-ness and forward-ness determines which tubes pair well and which don't with my I+ V5. My Voskhods 6ZH1P-EV, while also belong to the "warmer" group, doesn't take the bites away from my SR325e. Or, my CV4010 would turn my Nightwish listening session into a bombastic cinematic experience that any Tarja Turunen fan should have the chance to enjoy. It's is with this combo that _Over the Hills and Faraway _fires its denied-for-10-years emotions into the oceanic soundstage.
 Wait, what did I say? "Soundstage"? Yep that's right, with the I+ V5 now my SR325e actually has a big one! Ask any Grado fan (like me) about these Brooklyn handmade's weakness and the first word comes to mind should be soundstage. Thankfully the I+ V5 is here to help! Actually, my tubes and the Little Dot already opens the soundstage a bit in comparison to the benchmark O2 ODAC sound, but it's with the V5 SS that a Grado fan can experience the spacious feeling that, say, AKG K612 users are used to. Now instead of me sitting onstage with the guitarist, the bassist and the drummers, I can hear them playing onstage with me taking a comfortable sip in a middle-row seat. Sure, it does take a bit of intimacy away, but that's totally acceptable for someone who's not really into Jazz like me. It's interesting to hear the wife proclaim "Oh, it sounds really wide!", which she never did on a Grado.
 That all said, the soundstage here is more wide than deep, and it's still not as 3D as what you'd have on a true crossfade amp/DAC. But don't be surprised if upgrading the stock opamp to the V5 SS feels like you just switched headphones. 
 Details have never been a strength of the SR325e in comparison to its higher-priced siblings in the RS, PS and GS lines, but at least on my I+ V5 there's no such thing as "I can hear this on the $700 RS1i but it's nowhere to be found on the SR325e". The quality of those details is another matter, but I think the Eagles diehard in me is quite pleased with what I got on _Hell Freezes Over_. And let's face a somewhat unpleasant truth: the LD I+ is a cheap tube amp, so in the stock configuration more often than not it would take away those micro details we crave rather than accent them up. The V5 opamp and more detail-oriented tubes like the GE JAN and the Voshkhods would help resolve that problem, though much cheaper opamp like the MUSES8820 and 8920 can also do that. Anyway, just take away the stock opamp and put into the I+ something of quality and you can enjoy nitpicking those details out of your favorite Indie tracks.
  

_My beautiful, beautiful SR325e._
  
 One thing I like the most about Grados is how easy it is to change the sound by changing the pads. This adds another dimension to the tune-ability of the whole sound signature. On songs where even the V5 SS cannot help the bass to be more prominent, I'd change to using the Sennheiser HD414 pads. Normally, this would result in a very unpleasant trade-off: the Grado soundstage, small as it is, would get reduced even more. Even Radiohead or Pink Floyd would become claustrophobic in that case. This is one more instance where the expansive V5 soundstage helps: it helps balance out the closeness that the Sennheiser pads bring, allowing me to enjoy the bass without any particular trade-offs.
 All in all (for the SR325e), experiment all you can, but I think how much you'd like the V5 on your LD I+ really depends on what kind of tubes and what kind of headphones you're using. For me, the tube shouldn't be too laid back.


----------



## Lohb

Looking forward to any V5 vs V5i reviews to see if such open amp solutions are necessary !


----------



## WilliamLeonhart

cjg888 said:


> Frankly, for high impedance cans, the Mk III would be better...


 
 Agreed. But he/she bought the I+ already...


----------



## pelopidas

Concerning the V5 and V5i as replacement for a buffer like lme49600 and BUF634.. absolutely not. Those are current followers. They add current to the signal only. The V5 and V5i are opamps meaning they amplify a signal, increasing the voltage. That is their purpose. Yes, you can use opamps for things like cmoys but it sounds terrible (relatively speaking). The more load on an opamp, the worse it sounds.
 I have a V5 for my I/V stage and am using LME49600 for the buffer. It is absolutely lovely.
  
 I will also be adding a V5i vs V5 review in the near future. It's not ripe yet though.


----------



## pelopidas

As a funny side note; Who here would buy these "Elna Silmic" capacitors from ebay?
 the ad says 0.99c for 4 of these beauties.

 The seller is called atop_authentic_auction  so since he says that he is authentic, it must be so....


----------



## Renfield1217

pelopidas said:


> Concerning the V5 and V5i as replacement for a buffer like lme49600 and BUF634.. absolutely not. Those are current followers. They add current to the signal only. The V5 and V5i are opamps meaning they amplify a signal, increasing the voltage. That is their purpose. Yes, you can use opamps for things like cmoys but it sounds terrible (relatively speaking). The more load on an opamp, the worse it sounds.
> I have a V5 for my I/V stage and am using LME49600 for the buffer. It is absolutely lovely.
> 
> I will also be adding a V5i vs V5 review in the near future. It's not ripe yet though.
> ...


----------



## jh4db536

Rolled in 4627's and couldn't be happier. Clear treble without any rough edge which balances out the HD650's darkness. It's what i expected the AD843 to be. Bass is a lot lighter than the OPA627's but not out of control and loose. Everything is more balanced overall.


----------



## pelopidas

Hey Ren
I am currently running V5i in the I/V and the buffer position of my Xonar HDAV. 
Same basic circuit as the stx. 
In the buffer position of the DAC, which is what the Xonar is, the V5i is great. 
The STX has its own separate buffer that drives the headphones called TPA6120a2
That is the equivalent to the lme49600 buffer that I was referring to. That is also what 
Zulkr9 was asking about. Regular opamps (even great ones like the Bursons or SS3602)
Are not equivalent to dedicated current followers like lme49600 or tpa6120. These are
Designed to drive real loads and make your head bob to fat bass. In the DAC you have the I/V
that amplifies the wee little signal to a usable line out signal. The buffer is
there to insulate the I/V stage from the little load of sending that signal through wires to an amp. 
The amp will have really high input impedance so that basically no current is needed. Just the 
A/C voltage. 
Cmoys are basically a thought experiment to teach how opamps work. But anybody
who has moved up to a real headphone amp knows the difference. The difference is 
having a dedicated buffer meant for driving headphones. (And a good psu)
I didn't mean to get long winded in my explanation  just wanted to clarify the different buffers.


----------



## abartels

pelopidas said:


> As a funny side note; Who here would buy these "Elna Silmic" capacitors from ebay?
> the ad says 0.99c for 4 of these beauties.
> 
> The seller is called atop_authentic_auction  so since he says that he is authentic, it must be so....


 
  
 Hahahahaha, seller is right, those are "REAL AUTHENTIC FAKES"


----------



## afshin

hi
  
 It's just old selmic  design ... These are nan ROHS and original japan part.But They electrolyte dried.... Of 1995
  
 thanks.afshin


----------



## Foxer

pelopidas said:


> I have found that putting a 10uf Silmic II on the power pins makes a more profound improvement than a 0.1 film. The board will already be bypassed with various capacitors to keep the opamp stable but the power might be filtered with "average" capacitors in the first place. Putting a quality capacitor on the chip in essence cradles the opamp in its sonic signature vs the signature of the other capapcitors. If you want really deep and full bass put a 10 uf Silmic II on the chip. It's better than any other capacitor I have tried.


 
 so basically, 8 months later.. 
	

	
	
		
		

		
			





 (original post here: http://www.head-fi.org/t/432749/the-opamp-thread/5010#post_12074439 )
  
 After many trials, came back to report that this wasn't such a good idea.. 
 I ended up trying both the 10uF SILMIC II paired with the 0.15uF Wima @250v. The bass ended up being all over the place (too intrusive over the mids), blurred details, boring highs, and so on..
 Removed the SILMIC, and left only the wima, and things are much much better.. 
 And compared to if there was nothing on the opamp: with only the wima, it's slightly better.
  
 Opamp used: OPA1602AID on the CREATIVE X-Fi Elite Pro.
  
 The thing is, i already had replaced the card's original OpAmp power caps with silmics.. And the ones between the DAC and Opamp.. and the details already are a bit blurred by them..  So i dunno.. (to many silmics?!)
 I was thinking to replace the ones on the power supply side of the Opamp, with Panasonic FM's.. maybe they might restore some clarity (???)


----------



## Lohb

pelopidas said:


> Concerning the V5 and V5i as replacement for a buffer like lme49600 and BUF634.. absolutely not. Those are current followers. They add current to the signal only. The V5 and V5i are opamps meaning they amplify a signal, increasing the voltage. That is their purpose. Yes, you can use opamps for things like cmoys but it sounds terrible (relatively speaking). The more load on an opamp, the worse it sounds.
> I have a V5 for my I/V stage and am using LME49600 for the buffer. It is absolutely lovely.
> 
> I will also be adding a V5i vs V5 review in the near future. It's not ripe yet though.


 
 Would 4x LME49600 be an improvement over dummy buffers after the V5i slots ?
  
 I have an iBasso PB2 and will be using current hungry planars on the balanced connection in future.
  
 http://www.ebay.com/itm/1pc-LME49600TS-LME49600-49600-Buffer-op-amp-On-8pin-DIP-suit-RSA-XP7-/221633698050?hash=item339a65d902:g:sEAAAOSwkNZUir7c
 http://www.ebay.com/itm/1PCS-LME49600TS-LME49600-ON-DIP-ADPTER-REPLACE-BUF634-/321270074527?hash=item4acd304c9f:g3AAAOxyUrZSpDYc
  

  
 Just using IEMs on the SE connection just now.....


----------



## ph0n6

Hi. I just got an iBasso P5, wonderful amp though I do wonder if upgrading opamps are worth it. Currently using the dummy ground, BUF634 (low current mode) stack with their discrete buffer (and I prefer the discrete one compare to the BUF634 wide bandwidth), Anyway there are quite a few choice of driving opamps these days and personally I'm looking at the SS3601/2 or the V5i (seems to be the best on the market at the moment). Their prices are quiet steep though so I do wonder if they improve the sounds that much. Currently using 2 627AP, have the AU version from iBasso too but I much prefer the AP (DIP8) one.


----------



## abartels

afshin said:


> hi
> 
> It's just old selmic  design ... These are nan ROHS and original japan part.But They electrolyte dried.... Of 1995
> 
> thanks.afshin


 
  
 After some investigation you could be right these were the first series Silmic with matte brown sleeve and silver text, but, then again, why would one want to buy a capacitor of this kind of age?
 Those maybe are 10 years old!!!


----------



## afshin

hi
  
 Yes...These are very old and broken.
  
 thanks afshin


----------



## Mad Max

ph0n6 said:


> Hi. I just got an iBasso P5, wonderful amp though *I do wonder if upgrading opamps are worth it.* Currently using the dummy ground, BUF634 (low current mode) stack with their discrete buffer (and I prefer the discrete one compare to the BUF634 wide bandwidth), Anyway there are quite a few choice of driving opamps these days and personally I'm looking at the SS3601/2 or the V5i (seems to be the best on the market at the moment). Their prices are quiet steep though so I do wonder if they improve the sounds that much. Currently using 2 627AP, have the AU version from iBasso too but I much prefer the AP (DIP8) one.


 
  
 The amp was precisely built for that purpose.  Roll like crazy, though take care about which you choose, not just any will work, but most of the ones discussed in this thread will.  You have to take care of what the voltage supplies are in the P5 and be checking opamp datasheets from manufacturers' websites to make sure that they can handle the voltage, and what the pinout of the opamps are and whether it is two-channel or one-channel.  There's a small number of opamps with odd pinouts, most are the same.
  
  
  
  
  
  


jh4db536 said:


> Rolled in 4627's and couldn't be happier. Clear treble without any rough edge which balances out the HD650's darkness. It's what i expected the AD843 to be. Bass is a lot lighter than the OPA627's but not out of control and loose. Everything is more balanced overall.


 
  
 4627 is absolutely fantastic!


----------



## WilliamLeonhart

Can anyone with the Sparko tell me which side of the opamp should be on the half-moon side? Looking down is it the side that has a tiny gold plate and the number 1 next to it, or is it the side that has SS3602?


----------



## ph0n6

williamleonhart said:


> Can anyone with the Sparko tell me which side of the opamp should be on the half-moon side? Looking down is it the side that has a tiny gold plate and the number 1 next to it, or is it the side that has SS3602?


 
 The Sparkos site have instruction for it:


----------



## msknight

In my limited experience, pin 1 is normally at the "North" like the picture a few images down on here - http://msknight.com/bbc/sideways.html
  
 However, a double check is very much advisable.


----------



## WilliamLeonhart

ph0n6 said:


> The Sparkos site have instruction for it:


 
 Thanks for the tips, but it's still clear to me. My SS3602 shipped with an extender that actually has a half-moon shaped on it to mark, but in haste I plugged it out and now I don't know which direction was which.


msknight said:


> In my limited experience, pin 1 is normally at the "North" like the picture a few images down on here - http://msknight.com/bbc/sideways.html
> 
> However, a double check is very much advisable.


 
 Is the "North" the side that normally has the half-moon shape?


----------



## Renfield1217

williamleonhart said:


> Thanks for the tips, but it's still clear to me. My SS3602 shipped with an extender that actually has a half-moon shaped on it to mark, but in haste I plugged it out and now I don't know which direction was which.
> Is the "North" the side that normally has the half-moon shape?


 
  
 Hi WilliamLeonhart,
  
 Yes, the Sparkos opamps ship with an extender to protect the pins during shipping. This should be removed before
 installation of the opamp. The pin #1 designation is shown by an L shaped marking on the top of the opamp. As shown on this page  sparkoslabs.com/discrete-op-amps  just scroll down to the illustrations.
  
 Hope this helps,
  
 Ren


----------



## ph0n6

This should help 






The instruction point out the location of the Number 1 pin, compare to the upper image and you can find how it should be plugged.


----------



## WilliamLeonhart

Guys thank you all for your help, I plugged in the SS3602 and currently enjoying it without any problem!


----------



## SpudHarris

Any love for the AD825?


----------



## zilch0md

williamleonhart said:


> Guys thank you all for your help, I plugged in the SS3602 and currently enjoying it without any problem!


 
  
 Good news.  What do you think of the sound?  And what did you replace with the SS3602?
  
 Thanks!


----------



## luckyeights

Any comparisons yet of the V5 vs V5i i am planning on replacing the opamps in my sound blaster zxr with these, 2x V5i duals for I/V and the singles for the buffers.  Unless you have a better suggestion.
  
 Thanks


----------



## Audio Addict

luckyeights said:


> Any comparisons yet of the V5 vs V5i i am planning on replacing the opamps in my sound blaster zxr with these, 2x V5i duals for I/V and the singles for the buffers.  Unless you have a better suggestion.
> 
> Thanks




If the v5S of v5D fit, you should use those. Use the v5i for space restricted application as it is still an IC chip at the heart, just custom tweaked.


----------



## WilliamLeonhart

zilch0md said:


> Good news.  What do you think of the sound?  And what did you replace with the SS3602?
> 
> Thanks!


 
 The Burson V5 SS. I'm having both. Both sounds great but the SS3602 seems more neutral. 
  
 Does anyone here roll opamps on the Objective2? From what I understand, it seems that the U2 opamp won't affect sound quality, the U3 and U4 opamp will be used for low-gain and the U1 will be activated in high-gain. Is it true? If not, please correct me. Cheers.


----------



## luckyeights

So you would say the v5 is a little warmer than the SS3602 ?


----------



## zilch0md

williamleonhart said:


> The Burson V5 SS. I'm having both. Both sounds great but the SS3602 seems more neutral.
> 
> [snip]


 
  
 Thanks William!
  


luckyeights said:


> So you would say the v5 is a little warmer than the SS3602 ?


 
  
 Having come from the Burson V5 duals to the SS3602 (in an iBasso PB2), driving HD 800 or DT880 600), and switching back to the V5 for a day after several weeks of using the SS3602...
  
 I think* they're both really close in terms of neutrality - they have no coloration*. I personally can't say which is warmer, if at all. Maybe it's just how they are performing in my chain.  
  
 To me,* the most readily discerned distinction is the SS3602's power-related improvements in dynamics and bass control *(a difference not likely to be noticeable with efficient headphones or IEMs). *Another difference is the V5's laid back presentation*, putting you in the 10th row vs. at the edge of the stage with the SS3602. I don't know how to better describe the difference in perspective except to say that the SS3602 is more engaging, more immersive, where the V5 reminds me of the Burson Soloist's similar trait of leaving you set way back from the action.
  
 I sold the Burson Soloist because of that and its excessively smooth (resolution-reducing) treble region, but the V5 suffers no loss of detail in the highs, nor does the SS3602. They are both spectacular at separating out the busiest of well-recorded treble signals, but I would have to vote for the SS3602 when it comes to wrapping some blackness around each and every tiny little signal, all the way down to the lowest energy signals next to the noise floor, as heard with highly resolving headphones, while using a very detail-retaining DAC. This creates an even bigger soundstage with the HD800, especially, and restores some of the naturalness of the original analog performance, but this is a distinction which can't be heard at all with the not-so-resolving LCD-2 rev.1 or the Oppo PM-1, for example, and only somewhat with the "poor man's HD800" - the DT880 600 with balanced mod (when driven with plenty of power and, thus, yielding faster transients). It can't be heard when I use a "softer" source, like my NOS Octave MkII DAC, either. In this regard - an excessively-analytical look at what's happening to the micro-details down near the noise floor with an ES9018K2M DAC (Oppo HA-2) and highly resolving headphones, the Burson V5 almost has a "glow" around the low-level signals - they aren't as well delineated - but I'm splitting hairs to say that, especially since I only hear it with the HD800.
  
 In terms of detail, overall, with every headphone other than the HD800, just as with frequency response, I'd say the V5 and the SS3602 are so close I can't pick a winner, but *if you want to hear a more dynamic, punchy presentation, especially with power-hungry headphones, with tight control and texture heard in the bass frequencies especially, and an up-close and personal soundstage, the SS3602 is the better choice.* Let me temper that by saying the differences are subtle. Don't expect huge improvements going from V5 to SS3602, unless you've got a headphone that's still begging for more power with the V5.
  
 And I have to add, the SS3602 quality of construction is in another league altogether compared to the Burson V5 (50% of which have arrived with defects, in my limited experience.)


----------



## luckyeights

I am space constricted but its not like i couldn't mod the hell out of everything to make them fit.  But what it comes down to is how much of an improvement are the v5s over the v5is and is it worth having to do other mods to accommodate them over the v5i?  That is why id love to hear a good comparison of the two from someone to see is it worth the extra cost and the moding that would need to be done.  Or are they close enough that one shouldn't fret over one or the other.  
  
 Thanks


----------



## Audio Addict

luckyeights said:


> I am space constricted but its not like i couldn't mod the hell out of everything to make them fit.  But what it comes down to is how much of an improvement are the v5s over the v5is and is it worth having to do other mods to accommodate them over the v5i?  That is why id love to hear a good comparison of the two from someone to see is it worth the extra cost and the moding that would need to be done.  Or are they close enough that one shouldn't fret over one or the other.
> 
> Thanks




If you are are space confined, I would suggest considering the Sparkos Labs discrete opamp. Otherwise I would agree it is too close to call. One thing I would mention, it seems the Sparkos Labs run warmer given they fully operate in Class A.


----------



## zilch0md

audio addict said:


> If you are are space confined, I would suggest considering the Sparkos Labs discrete opamp. Otherwise I would agree it is too close to call. One thing I would mention, it seems the Sparkos Labs run warmer given they fully operate in Class A.


 
  
 Perhaps it's because I'm running them at a lower supply voltage than you are, but my two SS3602 run very coolly.  I'm running them at +/- 12.6V, but they can handle up to +/- 22V.  
  
 One thing's for sure, the SS3601 or 2 will not overheat in a foam-filled orange plastic coffin that melts after it has cooked the components within.  (This has happened in Gustard H10 amps, where the supply voltage has been measured at 1/2 a volt to 1 volt higher than the factory spec maximum allowable voltage of 16V, but where's the heat supposed to go under normal operating conditions, when the components are embalmed in a foam-filled plastic case?)
  


Spoiler: Warning: Spoiler!


----------



## Audio Addict

zilch0md said:


> Perhaps it's because I'm running them at a lower supply voltage than you are, but my two SS3602 run very coolly.  I'm running them at +/- 12.6V, but they can handle up to +/- 22V.
> 
> One thing's for sure, the SS3601 or 2 will not overheat in a foam-filled orange plastic coffin that melts after it has cooked the components within.  (This has happened in Gustard H10 amps, where the supply voltage has been measured at 1/2 a volt to 1 volt higher than the factory spec maximum allowable voltage of 16V, but where's the heat supposed to go under normal operating conditions, when the components are embalmed in a foam-filled plastic case?)
> 
> ...


 
  
  
 On the SS3601/2, do you leave them in the adapter they come in or use them straight into the 8 pin dip?


----------



## zilch0md

audio addict said:


> On the SS3601/2, do you leave them in the adapter they come in or use them straight into the 8 pin dip?


 
  
 I had to remove the adapter to reduce their height - so that I could put the lid on the case of my iBasso PB2.
  
 One thing I've noticed about the SS3602 is that their pins are not as large in diameter as the pins of other opamps I've owned.  I haven't measured them with a micrometer, but it's easy to tell the pins are not as thick because they just aren't gripped as tightly by the sockets as are the pins of other opamps.  This hasn't been a problem at all - just an observation.  
  
 I should also mention, in case anyone decides to follow in my footsteps, that the dimensions of the SS3602 are about 1.5mm too great to allow them to be fully seated into the DIP sockets - due to interference from the gain jumpers:
  

  

  

  
 Amazingly, despite the skinnier than normal pins and their not being fully seated, I have had absolutely no problems with running them this way.  I shook the PB2 pretty violently once, to see if I could cause the SS3602 to come loose, but they did not and now that I've had the case closed for several weeks, I continue to experience no problems at all.  Still, it bugs me that they are sitting in there at an angle, but it sure beats running around with a pair of Burson V5's sticking up with no lid on the case.  
  

  
 Of every combination I can build, among all of my desktop and portable gear, including the HD800 or LCD-2 Rev. 1 or Oppo PM-1, the Metrum Acoustics Octave MkII DAC with Aurix amp or the Oppo HA-1 or my venerable DACmini CX, this chain, pictured above, is *my current favorite setup for listening.  *
  
 Tidal HiFi > Apple Touch 6 > Zeskit Lightning to USB cable > Oppo HA-2 ES9018K2M DAC > Cardas HPI interconnect > iBasso PB2 with 2x Sparkos Labs SS3602 and dummy buffers > balanced Toxic Cables _Silver Poison_ > Beyerdynamic DT880 600-Ohm (balance mod done by BTG-Audio) with Beyerdyamic EDT 770 S pleather pads (for more bass energy than had with the stock velour pads)
  
 When supplied with enough power, I consider the DT880 600 with pleather pads to be a poor man's HD800 - with better bass energy, a more enjoyable treble, but with slightly less but still astonishing resolution (slightly more forgiving), a somewhat smaller soundstage and ever so slightly recessed mids.  My HD800 is gathering dust.


----------



## northendjazz

On jumpers I replaced them short ones to allow LME49600 buffers in my P4, not as quick to change gain but if your leaving it on high then they would seat fully. I managed to fit a pair of SS3601's in my Neco Soundlab V4 with 8dip sockets to raise them over the caps,
  
 I'll post pics if needed?


----------



## Audio Addict

zilch0md said:


> Perhaps it's because I'm running them at a lower supply voltage than you are, but my two SS3602 run very coolly.  I'm running them at +/- 12.6V, but they can handle up to +/- 22V.
> 
> One thing's for sure, the SS3601 or 2 will not overheat in a foam-filled orange plastic coffin that melts after it has cooked the components within.  (This has happened in Gustard H10 amps, where the supply voltage has been measured at 1/2 a volt to 1 volt higher than the factory spec maximum allowable voltage of 16V, but where's the heat supposed to go under normal operating conditions, when the components are embalmed in a foam-filled plastic case?)
> 
> ...




I am using them in the SSA Lycan. I rearranged the Lucan to get better airflow under it. That seems to have help greatly.

It is being fed from a Pulse Infinity v2 which tonight is being fed from Tidal via the Pulse Blue via digital SPDIF.


----------



## Technics

Hello all
  
 My Marantz and most of my CD players have the LM4562 which I find is great.  I have a Technics MASH cd player with the SMDs type of opamps needed. I love details clarity, soundstage - listen to rock classical and vocals. I got free shipping with Element14 till 29th of this month ! 
  
 I was thinking of going out of my comfort safe zone - LM series to try a OPA
  
 OPA1602?
 OPA1642 ? expensive
 OPA 1612 ?
  
 any of these would be a better over say a LME49720 /LM4562
  
 Thank you
 Kind Regards
 Sam


----------



## zilch0md

northendjazz said:


> On jumpers I replaced them short ones to allow LME49600 buffers in my P4, not as quick to change gain but if your leaving it on high then they would seat fully. I managed to fit a pair of SS3601's in my Neco Soundlab V4 with 8dip sockets to raise them over the caps,
> 
> I'll post pics if needed?


 
  
 Hey, thanks for that suggestion! I hadn't considered it previously.  
  
 Looking at my photos, above, I think I could get the SS3602 to sit almost flat, but not quite, if I had jumpers that were only a tiny bit taller than the jumper pins.  I will experiment with this. Thanks again!


----------



## zilch0md

audio addict said:


> I am using them in the SSA Lycan. I rearranged the Lucan to get better airflow under it. That seems to have help greatly.
> 
> It is being fed from a Pulse Infinity v2 which tonight is being fed from Tidal via the Pulse Blue via digital SPDIF.


 
  
 Oh, thanks for this info.
  
 The Lycan specifications don't say, but I think it reasonable to assume it provides the op-amps with a supply voltage closer to the Burson V5's maximum of +/-16V, where my iBasso PB2 is running at +/-12.6V when the 3-cell LiPo battery is fully charged, less as it discharges. That could explain my SS3602 running cool while yours run warm.  
  
 I've never actually measured the operating temperature of the SS3602 in my rig, despite having a laser thermometer that I've used in the past when op-amps are obviously hot to the touch. But improving the airflow is never a bad thing, that's for sure.


----------



## luckyeights

Well i just ordered 3 dual and 2 single Burson V5is for my zxr the one extra dual for my Xudoo xd-05 i ordered from massdrop.  It came down to cost and space constraints.  If anything they should be better than any other IC opamp on the market even if they are not as good as V5 they should be the best option out in that price bracket.   The sparkos were just out of the question for me way too expensive twice the cost of the V5is.  The V5s are cheaper than the sparkos but still expensive and then the size i would have to remove the emi shield off the zxr which who knows what would happen in my case with the GPU being so close.  So this felt like the best option,
  
 Guess we will find out if they are an improvement over the stock ones when they get here.


----------



## WilliamLeonhart

Any thought on the v5i vs the v5ss yet?


----------



## Renfield1217

williamleonhart said:


> Any thought on the v5i vs the v5ss yet?


 
 Hi Will,
  
 Got some Burson SS5Vis for a review have not listened to the V5SS's yet but seems Burson is replacing  the V5SS's with  the V5i's


----------



## abartels

renfield1217 said:


> williamleonhart said:
> 
> 
> > Any thought on the v5i vs the v5ss yet?
> ...


 
  
 Burson isn't replacing V5 with V5i, they just are solving their V5 production troubles. Since there was a big percentage of V5's who did die after some hours of playing, and some even were DOA.
 They are solving those troubles out, and V5 will be available as soon as production process is 100% OK.
  
 I have V5i for reviewing purposes too, have to burn-in and will review within two weeks. Have holidays now, so I have plenty of time to review


----------



## WilliamLeonhart

abartels said:


> Burson isn't replacing V5 with V5i, they just are solving their V5 production troubles. Since there was a big percentage of V5's who did die after some hours of playing, and some even were DOA.
> They are solving those troubles out, and V5 will be available as soon as production process is 100% OK.
> 
> I have V5i for reviewing purposes too, have to burn-in and will review within two weeks. Have holidays now, so I have plenty of time to review


 
 This is very sad to hear. Hopefully they sort out whatever the V5 is going through. That all said, I've been using my V5 SS for weeks without any troubles. And it runs well in my LD I+, which isn't quite warm by itself actually.
  
 Anyway, guys, my "Bursonist ThaiTao O2" (Thai Tao is the name of the guy who made this opamp for me, also a very good friend):


----------



## SpudHarris

I said I wasn't going to get back into rolling but curiosity got the better of me regarding the Sparko Labs modules..

I now have a 3602 (dual) module and have to say that initial impressions are very positive. It's detailed but still engaging. I will be testing it in a few amps over time but so far I am impressed.


----------



## zilch0md

Hey Nigel,
  
 Welcome to Club Sparkos!  
  
 I'm listening to some Acoustic Alchemy tracks at the moment, with my Spakos-empowered PB2 > DT880 600 rig. Yet again, starting the day with my first cup of coffee and fresh ears, I am still amazed by the Sparkos SS3602.  
  
 I know you're not a fan of crystalline detail - a la OPA1612.  I, too, have grown away from that, somewhat, but as you've hinted, the Sparkos offers resolving power without brittleness.
  
 I'm looking forward to your most critical critique, after you've had them for a long while.


----------



## northendjazz

With a few millimeters to spare the sparko's fit in my Neco Soundlab V4 and gave me a reason to keep it. 
 I need to change the gain to do dt880 600's more justice but sounds delightful.  The first thing I noticed was the
 high's and how well the sparko's deal with them but that maybe because the dt880's live on my tube amp most
 of the time. I'll give them a proper listen and report back.


----------



## Audio Addict

My pair of S3601 came in and now have a quad I can try on my RSA Apache. When I took out the V5s, I found 1 of the wires on the extension legs had broke. It had not died but just touched enough to work.

With no burn in the spaciousness of the music has increased by a significant amount. The female vocals are intimate on Karrin Allyson's "footprints". 

Time to just kick back and listen.


----------



## SpudHarris

Hi Mike, it's good to be in the club 

You have me searching my stash for the LT1612's again but must have paired them with amps I've sold over time...

I have LT1678's here aren't they the dual version that Ron used to include in his TopKit??


----------



## zilch0md

spudharris said:


> Hi Mike, it's good to be in the club
> 
> You have me searching my stash for the LT1612's again but must have paired them with amps I've sold over time...
> 
> I have LT1678's here aren't they the dual version that Ron used to include in his TopKit??


 
  
 Actually, I had referenced the Texas Instruments (Burr Brown) OPA1612 duals, which are also available as OPA1611 singles - the op-amp found in the original Meier Stepdance.


----------



## Cruxiaer

Just received my SSV5OPAD this afternoon. So far they sound awesome. I believe some burning in is required, so I will amend the post when I know more.
  
 I only have the stock opamps with me, I will try my best to describe the transition from stock to SSV5. I also assume you are familiar with the stock opamps. English is not my first language so my description may suck so bear with it 
  
*Setup:*
 Asus Xonar STX II
 Audio Technica R70x - neutral sounding, relatively narrow sound stage.
  
*Audio track:*
 Mountains (Interstellar OST)
 Ghost Town (Adam Lambert)
 A Stutter (Ólafur Arnalds)
 好久不見 (楊永聰)
 Lighthouse (Patrick Watson)
 Heroes (Peter Gabriel)
 01;41 (Ólafur Arnalds and Nils Frahm)
  
*Original setup #1*:
 LPF Muses 8820
 I/V 2x Muses 8920
  
 Great low and mid. However I still find the mid and high a little lacking for tracks like Mountains and Ghost Town. The clarity is not there. There's no punch. So I decided to switch the I/V stage to 2x TI LME49720 to see how it goes.
  
*Setup #2:*
 LPF Muses 8820
 I/V 2x TI LME49720
  
 Extremely loud volume. Tight and heavy bass. Lacking when it comes to details. After prolonged use I realised the mid and high from this combination is very harsh and tiring. Definitely not suitable for usage for more than an hour. Actually I wouldn't recommend this setup for anyone, it's probably bad for the ears 
	

	
	
		
		

		
			




  
*Setup #3:*
 LPF Muses 8920
 I/V 2x Muses 8820
  
 Everything sounds great and sound as it is. Smooth mid and high, great bass. No real complaints here. This is very similar to the #1 setup but less amped high.
  
*Setup #4:*
 LPF SS V5 OPA-D
 I/V 2x SS V5 OPA-D
  
 The first thing I noticed about the change is cleanliness of the audio output and volume. Much cleaner and balanced volume. I tried a few more tracks, noticed a slightly wider sound stage on my R70x (almost non-existent before) and very detailed bass which I have never noticed before. Definitely noticed instruments I have never noticed before far in the background. Bass is less pronounce as compared to all setups above, less punchy but more detailed. Mid and high are well controlled as well, sounds a little warmer/mellower than before. Separation is a not a night and day difference than before but noticeably better. This setup is something you can listen to the whole day without feeling fatigued.
  
*Conclusion:*
 It costs $250AUD(180USD), so is it worth the money? Yes and no. My have a sorta mixed feelings with the upgrade(definitely an upgrade, no question about that). My R70x is about 350USD on Amazon and STXII is 250USD. As of now my dac/amp setup costs more than headphones and I believe that's where the problem lies. If you are a user whose aim to get a soundcard or amp is to make your high impedance cans to work as it should, there is no need to upgrade to the SSV5s. It makes a difference. yes but not worth the 180USD difference. However if you were to use some higher end headphones regardless of impedance, the SSV5s should make a huge difference to you without getting a new setup.


----------



## SpudHarris

Mike, have you ever tried LT1678 biased to class A??


----------



## luckyeights

Well I Got my Burson V5i and well to put it short and quick they are going back.  They do bring out a slight bit more detail maybe..... But i cant stand that far away feeling they give, i dont know how that works but i dont like it.  It leaves me feeling distant from the music and it seems to take the fun out of listening at least for me.  Oh well they are not really needed anyway i ordered them to to upgrade my ZXR but then the modi multibit came out and well you know what happened there.


----------



## Mad Max

northendjazz said:


> With a few millimeters to spare the sparko's fit in my Neco Soundlab V4 and gave me a reason to keep it.
> I need to change the gain to do dt880 600's more justice but sounds delightful.  The first thing I noticed was the
> high's and how well the sparko's deal with them but that maybe because the dt880's live on my tube amp most
> of the time. I'll give them a proper listen and report back.


 
  
 They actually fit in there?  Nice.


----------



## WilliamLeonhart

Have anyone tried the Earth Moon Sun something from Audio GD? They seems to be quite cheap


----------



## Mad Max

williamleonhart said:


> Have anyone tried the Earth Moon Sun something from Audio GD? They seems to be quite cheap


 
  
 And discontinued.
 I still have OPA Sun.  It is fun.  They all need upgrade decoupling capacitors, the stock Evox MKT suck majorly.  You can see more about that in audio-gd threads concerning the Compass (2009) and FUN amp/DAC combos and in this thread.


----------



## zilch0md

spudharris said:


> Mike, have you ever tried LT1678 biased to class A??





I haven't. Do you like it better than the Sparkos?


----------



## Lohb

Generally what will replacing a buffer with an opamp instead do for your main opamp upstream in the amp.... ?


----------



## pelopidas

Burson V5i
  
 First impressions without burnin in I/V in Xonar.
 Full, smooth, liquid.
 The original V5 SS was exceedingly detailed and sharp before burn in. This seems much mellower and softer.
 (Das Grosse Erwachen – Annett Louisan) instruments not clearly distinguished. Voice right between ears and is lovely.
 (Rehab – Amy Winehouse) muddled mess. Hard to distinguish instruments.
 (L’Amor – Arianna Savall) Soft and gentle, missing micro detail. Veiled.
 Makes me want to turn up the volume to catch that micro detail that I am used to. I can feel that much is missing. Muffled like when there is a haze vs a crisp cool day where you can see for miles.
 The blackness of the V5 SS is ethereal and weightless. The V5i blackness is heavier, smaller.
  
 Before burn in. Polite, no sibilance, good bass. Gets confused with many instruments of similar timbre.
 Decay is not good. Bass quantity is good but wooly, indistinct.
  
 Ok, after a little burn in:
 Treble is finally coming up. Separation is becoming better. There is something not quite right in the mids. I feel like I’m straining to hear the pristine detail from the V5 SS.
 Listening to Annett Louisan – Zu viel Information, there are sleigh bells or a tambourine but they sound like a bag of nuts right now.
 I hope this is only burn in. Will let it burn more… more!!!
  
  
 After sufficient burn in:
 These are actually really good. The treble is clear, fast and detailed. The bass is full and thick. They are obviously better than average chip opamps. More dynamic, smoother and more detailed.
 If you are wondering what to upgrade your JRC 2114 or 49720 or even the AD 797 and LME 49990 with and cost is a consideration, then go for the V5i. These are hands down better than those chips.
  
 If price does not matter or you already have the big boy V5 SS then these are not for you.
  
 Now, onto a problem that I have with the V5i.
 My favorite headphone amp is a variation of “The Wire”. Signal comes in and goes straight to the I/V stage. The output goes straight into an LME 49600 buffer and goes straight to the headphones. No resistors or capacitors in the signal path with one caveat. I have a switch to enable or bypass input capacitors, depending what source I am using. If the source has any offset I use the caps, If no offset then no caps. DC coupled perfection. To my ears this sounds better than a circuit with a servo. Perhaps I am not good enough at implementing a good servo, but I swear a servo does not sound as clean or dynamic as a circuit without it.
 So here is my first problem. The V5 SS give me 0.01 mv offset. The V5i produces a whopping 100mv for the two single V5i on an adapter and around 70 mv on a dual V5i. That is unacceptably high in my headphone amp. I have tried taming it with different resistor settings but based on the info in the data sheet, I don’t have the magic formula. (If anyone here can figure out the resistor settings, let me know and I’ll try them)
 So anyone who does not have output capacitors or a servo needs to check their offset before hooking up headphones if you have a V5i in your headphone amp.
 I understand that my particular amp is the most sensitive to this problem but I have not run into this kind of offset with any other opamp except the NE5534.
 The norm for a chip opamp in my setup is around 3 mw. The V5SS is really phenomenal in this respect.
  
 For me the V5 SS is the mike drop of all op amps. Since I put those in, there has not been one twitch towards the other opamps. I didn’t even think about them. Why would I want to pull out the V5 for any of those little chips?
 V5i has me thinking about how to fix it again. I added the Silmic II caps and of course they helped but… once you are spoiled, then what?
  
 Another small (non) issue is the lip on the metal cap. If you want to use two singles on an adapter, these will pose a problem. I ended up sanding the lip off so I could squeeze them together. However, there really is no reason to use two singles on an adapter. The dual already is two singles. No benefit to be had.
  
 Anyone considering the V5i needs to be aware that burn in on these is painful. It is the opposite of the V5 SS. The V5 SS starts off as sharp, the trebles are piercing and need time to mellow. The V5i starts off as dull and this is really frustrating. It is a muddy, bass heavy mess until it burns in. Once you are there, the instrument placement is correct and the bass is clean. Give these at least 100 hours before listening critically. Otherwise you will just pull them out.
  
 My conclusion: For their price range they are the best opamps. But if you spent any time with the V5 SS it will be very hard to live with the V5i. If you are moving up the opamp ladder, this is a significant improvement over the usual chip opamps. If space does not allow for V5 SS then (aside from Sparkos which I want to try out) the V5i will be your best bet.


----------



## afshin

Hi

I like if someone direct comparison between burson V5 opamp & opa2604 for LPF after DAC.
Thanks for any comments

afshin.


----------



## WilliamLeonhart

mad max said:


> *And discontinued.*
> I still have OPA Sun.  It is fun.  They all need upgrade decoupling capacitors, the stock Evox MKT suck majorly.  You can see more about that in audio-gd threads concerning the Compass (2009) and FUN amp/DAC combos and in this thread.


 
 Very disheartening to hear. After I've got my Bursons and my Sparkos op-amp I really want to try all the expensive op-amps in the world.


----------



## afshin

I thank any comment ...
 Now I am using this method.
 In position I/V stage opa2604 is a best .
  
 thanks .afshin


----------



## musikaladin

...*here* my XD-05 withh a V5i....


----------



## afshin

Hi
 opa1612 is a Bipolar-Input  opamp and burson v5i is a Fet-input Discrete  and opa2604 is a Fet-input ...
 Fet input opamp usually  Input impedance is much higher. It can sound so much alike.
 Thanks for any comments.
  
 afshin


----------



## pelopidas

I'm not sure input impedance has much effect on sound. When you look at the data sheet of an opamp (take the lme 49990 for example) you will see that it is rated to drive 600 ohms. That means it can drive from infinity down to 600 ohms without deteriorating the distortion values of the opamp. Once you start going lower than 600ohms the distortion rises as does the difficulty of the load. The lower the ohms (impedence) the more current it takes to drive and opamps are not really made to drive current. High ohms means the opamp is just swinging voltage and not pushing current. 
So the design of an opamp is to have, ideally, infinite input impedence and zero output impedence. This is great for driving another opamp or a dedicated current follower as a final buffer. 
This is THE weakness of the O2 design. The I/V stage amplifies the signal and sends it to a NJM4556 opamp. The designer NwAvGuy, liked that the design had low output impedence but the problem is that the 4556 is rated down to 150ohms. Many headphones are as low as 16 ohms. Even the higher rated 300 or 600 ohm headphones are dynamic and sometimes swing lower than 150 ohms. That little opamp can't ever sound great driving 32 ohm headphones. 
But it could sound just fine driving an amp. 
Pardon my rambling. I was just trying to say that I don't think it is the input impedance that makes opamps sound similar or different. It is the circuitry as a whole of the little chip that gives it its sound profile.


----------



## afshin

hi
 Thanks for your feedback ...
 Over the past 4 years my research on testing the op Amp. Without considering the effect of oscilloscope was triggered only by considering the effect of hearing sound.
 A lot of op amp was tested. With various materials such as Bi-polar and Fet and Difet.
 Di-fet input impedance is higher than the Fet. opa627 that is Difet.
 Fets with Bi-polars was very different sound altogether. The gap between the dark background and musical instruments in Fets and
 More dynamics in Bi- Polars.
 By studying the datasheet:
 Fets = better sound stage
 Fets designed for enhanced AC performance = More and deeper bass and greater sound stage.
 Fets designed for enhanced DC performance = Less bass and more detail.
 Fets designed for Hi speed = More dynamics
 Bi-polar = More dynamics and not deep stage . Dynamic vocal  is very good But theStage is missing.
  In between...
 The opa2604, opa604 in single . The input stage is two feet.It also has Distortion Rejection Circuitry .Recommended for I/V stage in datasheet . I have found the most balance opamp In every respect for I/V stage.I think using a film capacitor 1uf for bypass PSU Enough.
 In the datasheet clearly refers to the use of 1uf tantalum capacitors. But I say film cap has better audio character. Ceramic cap character failing for audio purposes.Their effects are piezoelectric effect. Even NPO and COG !But a little better.
 Of course, other issues such as capacitors and audio chain is important.
 The result of my thoughts. I thank any comments

  
  
 thanks.afshin
 .


----------



## pelopidas

Sounds like you have put some real effort into this. Very nice!
I would love to know which opamps gave you which results. This sounds like a fun experiment to follow. 
In general I would agree with no ceramics and no tantalums as a good rule of thumb (with exceptions). I really noticed this with a snubber circuit. The films were much more dynamic than ceramics. I was really amazed that a snubber circuit could have a flavor of its own. 
I used to believe that the "audio path" and the rest of the circuit were two seperate things but experience has shown that everything leaves a mark on the sound. Something else I have learned is that film caps are great in the role of input capacitors but actually not good as power supply bypasses. The effect is a squeezing of the soundstage. 
I think, if you haven't tried them already, that you will like the discreet opamps like the V5 SS. None of the opamps I have ever tested come anywhere close to the dynamics, details and the soundstage of those. 
Happy listening and keep us updated!


----------



## FritzS

I prefer FET - OPA626 and Supreme Sound Opamp V5 in my headphone amp


----------



## afshin

hi
  
 opa626 designed for ADC drivers   =    Analoge  to  Digaital  
 ---------  designed for DAC drivers   =    Digital      to  Analoge
 !!!


----------



## Lohb

fritzs said:


> I prefer FET - OPA626 and Supreme Sound Opamp V5 in my headphone amp


 

 What are the characteristics of FET vs other stuff that you like so much ?


----------



## abartels

Hi Guys,
  
 I got a SS V5i-D from Burson and tested it last week. First attempt did fail, not sure what I did wrong, but it definitely was NOT due to a faulty opamp.
 Probably I didn't fit it adequate in it's socket.....
  
 I used an I2S only, heavily modded  DIY AK4495SEQ based board, fed with seperate toroidals for digital and analog portion of dac board.
 The dac board is modified with Nichicon FG's for VREF, psu stages, and buffer for opamp. Most of them located underneath the pcb.
 Further I connected an Ian Canada's FIFO II + Isolator board + DualXO II board to the I2S input. Clocks used at DualXO II: NDK NZ2520SD
 FIFO II fed by separate toroidal and 0.8uV low noise psu, DualXO II fed by separate R-Core and 0.8uV low noise psu.
 Opamp used was an LME49720HA milspec version.
  
 Ian Canada's FIFO II is fed by a RaspBerry Pi 2 board using piCorePlayer (latest 3.0 version) which connects to LMS server.
  
 This combination worked very, very well for me. Thought this combination was at it's best, until I changed LME49720HA for the Burson SS V5i !!!
  
 Before final reviewing I did burn-in the V5i for 150 hours. I just did a short listening session when connecting the first time, cold out of the box, just for fun.
 As expected it sounded a little dull in my opinion, too much bass output and no controll, veiled soundstage and not very detailed. But, since I was aware of it's needed burn-in time I wasn't afraid at all 
  
 The Burson V5i really is a big step-up in sound quality in comparison to LME49720HA. It's much livier, big, wide and deep soundstage, very natural sounding!
 Vocal timbre, and timbre in common is very musical, bass control is huge, never heard this kind of deep powerful and tight bass control from an opamp! (it's almost like swearing when calling this V5i an opamp.....)
  
 I must say this opamp really comes VERY close to discrete amplifier stages, sounding very life like, not hiding anything, tons of details but still very musical!
 My verdict: If you can't go the discrete route, this surely is the way to go. I wouldn't be amazed if this Burson V5i is the BEST opamp available for bufferstage!!! And, I am very sure I heard discrete solutions in the past
 which performed much LESS than this SS V5i. Well done Burson!!!
  
 Next step: Comparing the V5i to Burson's flagship V5 
	

	
	
		
		

		
			




  
 Some pics:
  

  

  

  
  
 Regards,
  
 Alex


----------



## zilch0md

pelopidas said:


> Burson V5i
> 
> [snip]


 
  
 Thanks for this. I really enjoy reading your assessments. You are so "credible."  
  
 No rush, but if you ever get a chance to try the SS3602, I'd love to see how you think it compares to the V5 SS. (I, too, am a big fan of how the V5 SS sounds.)
  
 Mike


----------



## abartels

Thanks for the rep. Mike 
	

	
	
		
		

		
		
	


	



  
  
  
 Yesterday I incorporated FIFO II-Isolator-DualXO II in my "MonsterDAC". This dac will be used to test SS V5, will compare with SS V5i and a Chinese discrete opamp (OP01) 
  




  
 This is the "MonsterDAC" 
	

	
	
		
		

		
		
	


	



  

  
  





  Alex


----------



## Mad Max

What™


----------



## pelopidas

Hey Mike

I want to test the Sparkos as well. Discreet vs discreet. This is much more fun than lme49720 vs opa827. Look how far this hobby has come. 
I recently went a month without the V5 SS just testing out different chip opamps again for various reasons. Chips are so bad in comparison. I felt a non-stop urge to keep swapping and trying different combinations. So after wandering in the sonic desert for a month I have the V5 SS back in and I think what I missed the most is 
1: the 3D holographic soundstage. You can almost see where each sound is placed and it feels like it has a definable shape. 
2: the decay. I had almost forgotten how involving this aspect of the music is. 
3: the detail. Every whisper, creaking chair in the recording room and every note and harmony. 
I can't do chip opamps anymore. With the V5 SS back in I am listening to music again that I listened to over the last month just to hear it right. I'm listening to music again and not thinking about my Dac and my amp and opamps. 

So I guess that means that at this point only a Sparkos would be interesting to play with. 
For all other new readers. Consider the incremental cost of buying little chip opamps over and over looking for the " heavenly, angels singing," sound. It's not to be found in a chip. Go discreet. As with anything that is important and where quality matters "Buy once, cry once" ... You save money in the long run.


----------



## zilch0md

mad max said:


> What™


 
  
 Exactly!  LOL


----------



## zilch0md

pelopidas said:


> Hey Mike
> 
> I want to test the Sparkos as well. Discreet vs discreet. This is much more fun than lme49720 vs opa827. Look how far this hobby has come.
> I recently went a month without the V5 SS just testing out different chip opamps again for various reasons. Chips are so bad in comparison. I felt a non-stop urge to keep swapping and trying different combinations. So after wandering in the sonic desert for a month I have the V5 SS back in and I think what I missed the most is
> ...


 
  
 Great advice!  
  
 These "expensive" discrete op-amps are very affordable upgrades when you consider what they can do for "mid-fi" quality amps - as with the iBasso PB2, for example.  
  
 I would nevertheless caution people to tackle the weakest link in the chain, first - and that usually involves spending a lot more money than you would on a pair of these "expensive" op-amps - which are best appreciated when nothing else is in the way, so to speak. They would not be able to make any detectable contribution with most $200 headphones, for example.
  
 I've written this elsewhere and at the risk of losing credibility with people who don't believe great sound can be had without spending a lot of money, but for several weeks now, I've come to prefer the sound of my Sparkos SS3602-equipped PB2 with dummy buffers to any other amp I own, including my $1200 Metrum Aurix.  And, sad but true, I prefer the ES9018K2M DAC of my iBasso HA-2, fed with a Sony NWZ-A17 via a USB emulation cable (for FLAC files on microSD cards) -or- with an Apple Touch 6 (for Tidal HiFi via WiFi), to anything I can do with my Metrum Octave MkII (or with my the DAC and amp sections of the Oppo HA-1) - and that's for either the HD800 or PM-1 or my new favorite headphone by far - the DT880 600, modded with locking mini-XLR connectors for more power via balanced output from the twin SS3602's in the PB2.
  
 And, not just to support your enthusiasm for the Burson V5, I'll add that they were only barely knocked off their perch by the Sparkos - for my tastes, my gear, my ears. The V5 sound is a little smoother in the treble - and is also more laid back, less dynamic - again, that's with the HD800 and the "Poorman's HD800" (the DT880 600 - when supplied with plenty of power.)
  
 By the way, I really like the improvement made by using the SILMIC caps on DIP extenders - for the Burson V5 - as you had recommended, way back when):
  
*Elna SILMIC II 35v 10uF caps soldered for dual op-amps*
  
  
  

  

  
  
*But don't try using these caps, wired as shown, with the Sparkos SS3602 duals - at least not with the iBasso PB2*.  When I turned on the amp, I got a loud pop followed by no audio (but no harm done, apparently).  When I wrote Sparkos about it, he couldn't offer an explanation. I even repeated the "experiment" after confirming (with the caps removed) that no damage had been done to anything. I was certain that I had Pin 1 oriented correctly.  So, proceed at your own risk if you want to try adding caps across Pins 4 and 8 on the Sparkos SS3602.  They sound so awesome without adding caps - it wasn't as if I was trying to fix a problem. 
  
 Mike


----------



## pelopidas

Hey Mike!
  
 damn it.. you are talking me into spending 300 bucks to satisfy a curiosity itch. I hope my wife does not read this thread. 
	

	
	
		
		

		
			




  
 If your PB2 does not benefit from the Silmics then there is absolutely no reason to use them.
 When I first started playing around with the capacitors it was because some of my opamps (AD797 and some others) were prone to oscillating. I tried compensating to reduce bandwidth and that worked for the lme49990 but the 797 was being a bugger in my Xonar. Also I didn't really like the sound when compensated. 
 The reason I even tried putting a cap across the power pins was to help eliminate the oscillations. It worked. That is also where I learned of how profoundly it effects the sound of some opamps. 
 And the moral of that story is that you never know where the rabbit hole leads you.
  
 Here is another rabbit hole. I have played with alot of film capacitors. The first place a novice audio hobbyist goes is input capacitors. You learn the signature of whatever cap is your favorite and try to improve with bypassing etc. Well, the thing that was eye-opening is that film does not sound the same in a PSU position as in DC blocking input cap position. I have even come so far as to say that film is no good in psu position. 
 Electrolytic all the way for PSU. Low ESR is not predictive of good sound. High ESR is not predictive of bad sound. Electrolytics are more Art than Science when it comes to sound. 
 But here is what I found with film caps. They squeeze the soundstage, never make it wider. I tried teflon. OMG its terrible when you bypass your PSU with that. It smears the trebble. It makes everything that is sharp sound round. 
 But as an input cap they are fantastic. 
 So that is my can of worms.. Who wants to go fishing with that? I'm not dogmatic, these are just my experiences with my equipment. I would love to hear what others think. 
 The easiest test is to put the largest value film cap you have on a dip adapter and put your opamp in there and listen.


----------



## NymPHONOmaniac

Hi guys, i'm not an OP-AMP Savvy dude and don't know nothing about it but I want to learn and especially heard the possibilities of soundsignature it can give.
   
 

 To begin with I see this portable amp that have 2 changeable OP AMP and wonder if it's a good buy:
 http://www.ebay.com/itm/Douk-Audio-Portable-Hi-Fi-Amp-Class-AB-Stereo-High-Current-Headphone-Amplifier/282074576928?_trksid=p2046732.c100040.m2060&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140107095009%26meid%3D21140dde269f45efaebee1ebe8e98ef6%26pid%3D100040%26rk%3D3%26rkt%3D4%26sd%3D272049263172&autorefresh=true
  
 Question is:
 Do dual OP AMP will sound better and give more power and precision?
  
 What should we look for in portable amp circuitry if any know?
  
 How can we know the Op amp we can use that will work with the amp?
  
 I search for something better than my Fiio E7 that have changeable Op amp option and is portable.
  
  
 Thanks for any toughs and help and sorry for my idiotic-looking questions!


----------



## canthearyou

Here is my little review/comparison between a few opamps. I was gonna do a big write-up but, life has gotten in the way of any real free time.
  
 See my amp mods here: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/150#post_12641691
  
 Audio chain: laptop>ifipower>Gustard U12>Gustard X12>Matrix M-Stage HPA3-B>HiFiMan HE-500
  
 With the little time I've gotten to swap and listen to a few opamps I've come to a few conclusions.
  
 Burson V5:
 A mellow sound, laid back, if you would. Nothing seems to stand out, all very balanced. Vocals seem to blend into the music(not sure if this is good or bad). And the soundstage seems to be on the small side.
  
 Burson V5i: Similar to the V5 but better in a few ways. The vocals sound so lifelike and energetic. Sounds as if the artists are in the room with you. Also the bass is more pronounced and lively. The soundstage is very good. Not too big or too small.
  
 Sparkos Labs SS3602: Very clear, almost analytical. Vocals are not veiled, but stale sounding. The instrument separation is ridiculous! Every single sound has its own space and time. You can really pick apart the music. The highs are very clear and pronounced not harsh at all, though. And the soundstage is on the small side.


----------



## WilliamLeonhart

Am I right to deduce that the V5i's soundstage is better than the V5ss?





canthearyou said:


> Here is my little review/comparison between a few opamps. I was gonna do a big write-up but, life has gotten in the way of any real free time.
> 
> See my amp mods here: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/150#post_12641691
> 
> ...


----------



## pelopidas

I would guess that the sonic signature is dependent on the equipment. Others have come to different conclusions based on different setups. One relative constant finding though seems to be that the Sparkos opamps are currently top dog. 
Canthearyou - consider also removing the other 4 nichicon caps and replace with silmic. That might help open the soundstage a little more. While the nicichons have always seemed correct to me, the soundstage has a defined radius that the silmics don't seem to suffer from. 

How long did you let all the discreet opamps burn in for? I'm just wondering because your findings are surprising to me.


----------



## canthearyou

pelopidas said:


> I would guess that the sonic signature is dependent on the equipment. Others have come to different conclusions based on different setups. One relative constant finding though seems to be that the Sparkos opamps are currently top dog.
> Canthearyou - consider also removing the other 4 nichicon caps and replace with silmic. That might help open the soundstage a little more. While the nicichons have always seemed correct to me, the soundstage has a defined radius that the silmics don't seem to suffer from.
> 
> How long did you let all the discreet opamps burn in for? I'm just wondering because your findings are surprising to me.




I did let the opamps burn for for many hours. But I was not able to give them the true listening due to busy schedule. I do plan on a thorough listening coming up in the off season.


----------



## zilch0md

pelopidas said:


> Hey Mike!
> 
> damn it.. you are talking me into spending 300 bucks to satisfy a curiosity itch. I hope my wife does not read this thread.
> 
> ...


 
  
 I, too, struggled with, but finally succumbed to that same curiosity itch, but no regrets this time. 
	

	
	
		
		

		
		
	


	




  
  
 If anything, I feel as if I shouldn't have bought the Burson V5, but I have so much affection for them, even though they are gathering dust at the moment, and if I had purchased the Sparkos first, I'd still be dying to know what the V5 sounds like. There's no escape!  
  
 That's what drives this industry more than anything else - _having to buy the book before we can read it.  _




  
 The distinction I had tried to make in my last post is that the SILMIC II caps sounded great with the Burson V5 duals in my iBasso PB2, but* the same caps, soldered across pins 4 and 8, caused the Sparkos SS3602 to make a loud pop and then no audio at all in the PB2*.
  
 But, again, I love the way those caps sound with the Burson V5 duals in my PB2, even though I've had no evidence of any problem with oscillation. 
  


canthearyou said:


> Here is my little review/comparison between a few opamps. I was gonna do a big write-up but, life has gotten in the way of any real free time.
> 
> See my amp mods here: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/150#post_12641691
> 
> ...


 
  
 First, I am again humbled by yet another person with amazing DIY skills.  I am so limited to "plug and play!"  
  
 Having not yet heard the Burson V5i, I'm intrigued by your comments regarding the V5 and the Sparkos SS3602.  I actually find them completely consistent with my own experience, except for your finding the V5 soundstage to be "on the small side."  Then again, for whatever reason, I've never been comfortable reviewing the depth and width of soundstage between any two components. I'm often amazed at how comfortable other people seem to be in this regard.  Maybe my brain is just a little bit more "mono" than that of others.  
	

	
	
		
		

		
		
	


	




  Even so, or perhaps because of my own inabilities, I never found the V5 soundstage to be confined in any way.  
  
 Everything else you've written about the V5 is spot on with my experience.  I liken the V5 sound to that of the Burson Soloist, which I owned for several months before selling it - because it was too laid back for my tastes - as if I was seated far from the stage. The V5 isn't nearly as bad in this regard, going on memory of my Soloist, but swapping in the SS3602 puts me right up front with the musicians.
  
 The V5 treble isn't nearly as smooth (as in "veiled") as the Soloist, either. I never felt I could extract all available detail using the Soloist, that I _can_ extract using the V5 in my PB2, but again, matching your assessment, the SS3602 pulls out every last bit of detail, and does so with no harshness - even with the finicky HD800, which has no tolerance for the brittle edginess I can hear with the Oppo HA-1, for example.
  
 And yes, with the SS3602, it's as if a blackness is wrapped around every morsel of sound. Violins have never sounded cleaner - and I hate violin ensembles, as a rule - only because they are so hard to reproduce accurately - often sounding like big blocks of coarse Styrofoam being rubbed together.  The Sparkos SS3602 presents violin ensembles with clarity, where, in comparison, the Burson V5 seems to put a very subtle "glow" around everything - allowing instruments to bleed into each other's space.  I'm being very picky here - this distinction is subtle, not strong. The V5 is wonderful with violins. It's just that there is a detectable improvement with the SS3602.
  
 tidal.com/album/34045841
  
 I'm looking forward to your more seasoned assessments - after you've had them for awhile.
  
  
 By the way, while in that thread you linked, I came across this post:
  
 http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/105#post_12393607
  




  
 That thing is really cool and, potentially, a big problem solver.


----------



## afshin

Hi
 I have a lot of film capacitors including Mundorf  of gold, silver, oil and capacitors Adiyon and many famous capacitors have worked ... I think not ... but they never squeeze soundsatge film capacitors are enriched sound. Sound much more dynamic and more alive ... and more natural sound similar to analog. silver capacitor have more dynamic.for bypass PSU usually a combination of Elna silmic and film power is good. Sonic character capacitor film is very different depending on the brand.I've never been a good result with Teflon capacitors!
  *capacitors can change the opamp character.*
  
 This article is a good reference for learning more about film capacitors. Appeared to bypass opamp even the same character.Do not forget the need to burn-in  of film capacitors long time.
http://www.humblehomemadehifi.com/Cap.html
  
 thanks.afshin


----------



## Lohb

zilch0md said:


> http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/105#post_12393607
> 
> 
> 
> ...


 

 In the case of V5i it may short out the dummy buffers as there is an un-needed metal lip around the chip that some have had to file off in some instances. For V5i it may also need a DIP socket to elevate it above touching the dummy buffers and then will the lid close finally ? No dimensions i could find off the links...bad connection now.
_I think Burson just need to ship this new generation V5i chip with no metal cube cap over it_ to make it more form-fitting to existing hardware layouts that were built around old school opamp chip dimensions.


----------



## Mad Max

afshin said:


> Hi
> I have a lot of film capacitors including Mundorf  of gold, silver, oil and capacitors Adiyon and many famous capacitors have worked ... I think not ... but they never squeeze soundsatge film capacitors are enriched sound. Sound much more dynamic and more alive ... and more natural sound similar to analog. silver capacitor have more dynamic.for bypass PSU usually a combination of Elna silmic and film power is good. Sonic character capacitor film is very different depending on the brand.I've never been a good result with Teflon capacitors!
> *capacitors can change the opamp character.*
> 
> ...


 
  
 WIMA, Vishay, Epcos, and Evox/Kemet don't take that long to burn in, in my experience.  Not even 8 hours.


----------



## Unclewall

I find that they still change over large time periods


----------



## ph0n6

Took some (painful) modding but the sounds of the sparkos is absolutely worth it


----------



## Lohb

ph0n6 said:


> Took some (painful) modding but the sounds of the sparkos is absolutely worth it


 
 Just about to get my set of Sparkos next 10 mins - cannot wait, based on the trusted impressions so far. The last piece in my hardware chain for a while.


----------



## Lohb

A nice little combo for my needs anyway...I felt dummy buffers held back heft and musical richness....


----------



## zilch0md

lohb said:


> A nice little combo for my needs anyway...I felt dummy buffers held back heft and musical richness....


 
  
 I should give that a listen - despite my preconceptions.  Which headphones are you using with the PB2?  Balanced or TRS jack?


----------



## Lohb

zilch0md said:


> I should give that a listen - despite my preconceptions.  Which headphones are you using with the PB2?  Balanced or TRS jack?


 

 SE - IEMs.
 BUT, it's prepping for planars balanced which are current-hungry vs voltage swing hungry, and if I read things right that specific buffer allows higher current flow vs dummies(?) thus the battery life goes down faster with that buffer.Anyway, it draws me in and its spot-on for me.
 I just like a meatier low/mids presentation, rather than the top-to-bottom airy transparency balanced type deal.


----------



## zilch0md

Your taste comes first - above everything else.  Go for what you like, my friend!  
  
 I do intend to give your setup a listen - but not until the weekend.


----------



## alota

canthearyou said:


> Here is my little review/comparison between a few opamps. I was gonna do a big write-up but, life has gotten in the way of any real free time.
> 
> See my amp mods here: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/150#post_12641691
> 
> ...


 
  
 hi, thanks for your impressions.
 please, one information: the sparkolabs is larger compared to burson v5i?
 thank you


----------



## canthearyou




----------



## hifihp

canthearyou said:


>


 

 Can you show the height different between those opamps?


----------



## alota

canthearyou said:


>



Really thanks.the sparko is too large for my amp...that shame


----------



## canthearyou

hifihp said:


> Can you show the height different between those opamps?




Not a problem. I'll get it tonight.


----------



## ph0n6

There should be Dimensions information of every opamp on their site so check it out. At least for the sparkos one.


----------



## alota

ph0n6 said:


> There should be Dimensions information of every opamp on their site so check it out. At least for the sparkos one.



I.found the dimensions in the site but the pictureis better


----------



## canthearyou




----------



## 37mil

Hi guys, just noticed this thread talking about the burson v5/v5i, dexa's and sparkos. A while back I posted a review in the Teac UD-501 thread comparing the v5 and sparkos duals. This was the original version v5 with the yellow coloured foam inside. I preferred the v5 by far - having a much quieter background, massive soundstage, deeper detailed bass, and more resolution with accurate timbre. As mentioned here, it did suffer from the back seat audience syndrome, which gave it a slightly more laid back presentation but to me it was acceptable considering all the other things it did so exceptionally well. Definitely the best op amp by far.
  
 Unfortunately, this was not long lived as both v5 installed in the 501 began to fail after probably around 200 hours usage at 12V. These were quite hot but not even as hot as the dexa's, i thought. The plastic housing which doesn't help heat dissipation probably helped kill it. This happened to another guy who installed it in his 501 as well. 
 Had to wait a long while whilst Burson tried to figure out a resolution, and finally shipped me a pair of new version v5's with black foam inside. These run a lot cooler than the previous version. Unfortunately, these new ones sound nothing like the original version. It has none of the attributes I described above, and worse of all, it is totally unmusical, a really weird presentation that you can't put your finger on until you realise it has sucked all life out of the music. 
  
 A real disappointment. I am now back to using the sparkos which are very good but way behind the original v5.
  
 If anyone has the v5i to compare with the original yellow v5, i'd like to hear about it. I'm thinking of possibly replacing the 4 remaining muses 01 in my teac with the v5i if they sound any good.


----------



## WilliamLeonhart

How do you find the Teac compared to other dac/amp in the price range?


----------



## 37mil

the teac is my most expensive dac. in stock form it's probably only as good as my marantz sa-14v2 (which is good because the marantz was much more expensive) but it's more moddable and versatile.


----------



## raoultrifan

37mil said:


> Hi guys, just noticed this thread talking about the burson v5/v5i, dexa's and sparkos. A while back I posted a review in the Teac UD-501 thread comparing the v5 and sparkos duals. This was the original version v5 with the yellow coloured foam inside. [...]
> 
> Unfortunately, this was not long lived as both v5 installed in the 501 began to fail after probably around 200 hours usage at 12V. These were quite hot but not even as hot as the dexa's, i thought. The plastic housing which doesn't help heat dissipation probably helped kill it. This happened to another guy who installed it in his 501 as well.
> Had to wait a long while whilst Burson tried to figure out a resolution, and finally shipped me a pair of new version v5's with black foam inside. These run a lot cooler than the previous version. Unfortunately, these new ones sound nothing like the original version. It has none of the attributes I described above, and worse of all, it is totally unmusical, a really weird presentation that you can't put your finger on until you realise it has sucked all life out of the music.


 
  
 Hi, 
  
 I believe this is your post http://www.head-fi.org/t/632413/teac-reference-line-ud-501-usb-dac-dsd/435#post_12405534. You were using 2 x V5 in LowPass Filter, right? In LPF gain is probably 1X or lower and sometimes V5 is oscillating because of that. A scope might show you something, though removing the big caps and replacing them with 0.1uF ceramic & 1uF tantalum soldered as close as possible to DIP8 socket could help a bit. Mundorf caps should only be used in signal path and not for decoupling (please double check original schematic from TI's datasheet for your PCM DAC). I've also seen some head-fiers improving TEAC's PSU either by replacing power regulators, either by adding/replacing PSU caps (feel free to check TEAC-501 thread).
  
 From what other readers wrote here on HeadFi the new V5i sounds about the same as V5, but it has less thermal issues.
  
 SS V5 powered from +/-12V has no thermal issues unless is oscillating.
  
 Cheers, 
 Raul.


----------



## 37mil

Hi, Raul, I used the v5 on the buffer stage. It must have been unstable for it to get so hot. The mundorf's are directly in the signal path unfortunately and anything less than 100uF is reducing the bass quite a bit. 

I've also replaced all power regs with Dexa's which are great and changed caps where possible. All great mods for this machine. 

Another forum member with the teac and same burnt out v5 said the v5i seemed like a cheap op amp in comparison so I don't know what to make of it. 

Thanks for your input.


----------



## raoultrifan

Oh, these are great mods you've done! Perhaps you could give it a try with V5i; if so, then get a scope and check the output signal after every opamp or at least at final output plugs (bandwidth of at least 10 MHz scope). Also, an IR thermometer or a direct contact one should be OK to measure the temperature for each opamp.
  
 Now, I'm just being very curious if V5i will get hot or not in your setup...


----------



## dukefx

Does anyone have any experience on how much the sound changes when the V5is finally burn in?


----------



## afshin

hi
  
 Burson v5i  hot in the beginning at start , but after a few hours were balanced and well...
  
 in start 
  
  
  
 after 1 day
  

  
 Thanks


----------



## raoultrifan

Interesting! What device is that one, please?
  
 I wonder how is it possible to have 76C in the first day and 37C the net day...quite strange I'd say. I'm so hoping I'll receive my V5i opamps this month to give'em a spin.


----------



## afshin

Hi
  
 Yes, it was very strange. Represent SS-Audio Told me that  high temps with the v5i is not usual. Sometimes there is a bad
  
 connection between components and it affects performance and  I think this is quite possible...
  
 The temperature opa627 In pictures at the same location.
  
  

  thanks afshin


----------



## afshin

Hi
  
 On the third day sound much better ... still good heat and low ...Great instruments and has a three-dimensional separation stage ... but I now pronounce some words in there ُُSsss  problem. It may be better to break-in more. In general, the chip is very clear and well 
  

  
 opa627 Installed in another location

  
 The sound was very good today. I want after burn-in install to LPF  DAC  WM8716 Wolfson  24bit 192khz 64X refresh  . 
  
 Tanks.afshin


----------



## dukefx

I'm quite satisfied with mine after it finally burned in.


----------



## Lickumms

Hey!
  
 I'm planning on upgrading the Op Amp in my xDuoo XD-05.
 I have it narrowed down to 2 different Op Amps:
  
 MUES02
 Burson v5i
  
 What do you guys think is the best option between these 2? Or is there something else I should be looking at in the $50 price range?
 Any help would be appreciated.


----------



## WilliamLeonhart

Either V5i or Sparkos. I prefer the V5 the most actually, but the V5i isn't far behind


----------



## Lickumms

Is the Sparkos SS3602 worth the extra money over the V5i?
  
 Edit: I don't think the SS3602 would fit in the XD-05


----------



## alota

lickumms said:


> Is the Sparkos SS3602 worth the extra money over the V5i?
> 
> Edit: I don't think the SS3602 would fit in the XD-05



I think the same. Too much large for xd-05


----------



## WilliamLeonhart

lickumms said:


> Is the Sparkos SS3602 worth the extra money over the V5i?
> 
> Edit: I don't think the SS3602 would fit in the XD-05







alota said:


> I think the same. Too much large for xd-05


 That is if you don't use opamp extender and really need to close the chasis


----------



## alota

finally arrived the burson v5i. installed and tried.
 well......i was, in the past, a set in the "high-end"guy. today, i´m more quiet and racional(my wallet sais thank you)
 So, apart jokes, the meaning is that today i have an entry level system but i really like it.
 when i ordered the v5i, i do not expect great things; probably a slight improvement but considering the price of the v5i, why not?????
 I state that i don´t believe in technological miracles, so i say that the v5i isn´t a miracle or a giant killer but a really good product considering the Q/P realtionship.
 The sound signature of my amplifier is the same but in first place the imagine is better and more focused and now i have a tight bass.
 it´s a refinement of good performance of my amplifier. but more important for me is the gain.  i use an oppo pm-3, so the gain is the lower.
 but, so even I could not lift much the volume. now the volume is more progressive.
 really satisfied
 p.s.: thanks to Charles of SS-Audio for the kindness


----------



## dukefx

Was it brand new? Mine was a disaster. It was overly bassy and clarity was worse than a cassette player from the 80s, but after 40 to 50 hours of torture it finally burned in.


----------



## alota

yes. some hours of listening.if in 50 hours is better, good LOL


----------



## canthearyou

dukefx said:


> Was it brand new? Mine was a disaster. It was overly bassy and clarity was worse than a cassette player from the 80s, but after 40 to 50 hours of torture it finally burned in.




How is that even possible?


----------



## raoultrifan

Just received V5i opamps and gave'em a spin in Voltage Amplification, Low Pass and Buffer stages in Essence One Muses MKii. I haven't done any A/B tests yet, so I will not say much, but I find the sound being pleasant and neutral too. I don't find it bassy, instead sound is quite balanced.


----------



## dukefx

canthearyou said:


> dukefx said:
> 
> 
> > Was it brand new? Mine was a disaster. It was overly bassy and clarity was worse than a cassette player from the 80s, but after 40 to 50 hours of torture it finally burned in.
> ...


 
 I have no idea, I'm wondering how it didn't sound bad at first for others. Burson Audio recommends 100 hours burn in, but 40-50 hours were enough for mine. I'm using it in an O2 and it sounds amazing now.


----------



## alota

I don' have any experience with opamps.
My chose was between the burson and muse. The muse is more expensive.
The only negative thing is shipment a little expensive. For a small package is too much


----------



## dukefx

Not to mention there are a lot fake Muses' floating around.


----------



## alota

dukefx said:


> Not to mention there are a lot fake Muses' floating around.



Right. I saw muse on mouser store. I think that are originals.


----------



## dukefx

Yeah, Mouser is quite reliable unlike ebay.


----------



## raoultrifan

alota said:


> I don' have any experience with opamps.
> My chose was between the burson and muse. The muse is more expensive.
> The only negative thing is shipment a little expensive. For a small package is too much




Hi,

What would you like the opamp for, please?

Thanks!


----------



## alota

raoultrifan said:


> Hi,
> 
> What would you like the opamp for, please?
> 
> Thanks!



Sorry but i don't understand your question


----------



## raoultrifan

In what equipment would you like to use it? Amplifier, DAC?


----------



## alota

raoultrifan said:


> In what equipment would you like to use it? Amplifier, DAC?



LOL, now understood. It's xduoo xd-05 amplifier-dac. A really good amplifier for the price


----------



## Renfield1217

dukefx said:


> Was it brand new? Mine was a disaster. It was overly bassy and clarity was worse than a cassette player from the 80s, but after 40 to 50 hours of torture it finally burned in.


 

 ​Hi dukefx,
  
 And was exactly my take with using 3 Burson V5is in my STXII. Takes a long time to burn in and even then they are not close to the Sparkos for clarity, instrument seperation, and dynamics.. They are nice opamps for the pricepoint and should be considered over most other monolithic op amps, but they still have that Burson laid back veiled sound.
 Personally I like detail and what to know the diff between a bad recording and a great one.
 No diss on Burson, just my take.
 Ren


----------



## dukefx

I did consider the Sparkos, but it won't fit. Even the V5i barely fits.


----------



## Renfield1217

dukefx said:


> I did consider the Sparkos, but it won't fit. Even the V5i barely fits.


 

 ​Totally understandable as far as the fit. I leave my shield off the STXII with the Sparkos still sounds awesome.
 And was not dissing the Burson V5i's, they do take a long time to burn in and even then they do not come close to the sound of the Sparkos.
 But at their price point they are very good.
 Btw, Sparkos also sells off ebay and you can make an offer on the opamps for a lower price.


----------



## gr8soundz

renfield1217 said:


> ​Totally understandable as far as the fit. I leave my shield off the STXII with the Sparkos still sounds awesome.
> And was not dissing the Burson V5i's, they do take a long time to burn in and even then they do not come close to the sound of the Sparkos.
> But at their price point they are very good.
> Btw, Sparkos also sells off ebay and you can make an offer on the opamps for a lower price.


 
  
 I've been looking at the Bursons and Sparkos for my Essence ST card.
  
 Only use the line out though so would I need 2 single opamps or 2 single and 1 dual?
  
 Not sure I trust ebay for authentic chips and wonder if the improvement is worth the asking price (three Sparkos would cost more than the card itself). Is the difference over stock opamps that dramatic or is it a subtle (yet still noticeable) improvement?


----------



## Renfield1217

gr8soundz said:


> I've been looking at the Bursons and Sparkos for my Essence ST card.
> 
> Only use the line out though so would I need 2 single opamps or 2 single and 1 dual?
> 
> ...


 

 Hi gr8soundz,
  
 The STX, ST, and STXII all use the same opamp setup. They use 3-duals so with Sparkos you would need 3-SS3602's (2 for the I/V sockets and 1 for the buffer/LPF). If you are using the headphone out only the I/V opamps are used, if you are using the line out then all 3 sockets/opamps come into play.
  
 This is the ebay store to buy from http://www.ebay.com/itm/Dual-Discrete-Op-Amp-SS3602-/141461456047?hash=item20efc284af:g:EqYAAOSwCZ5Vfdzn
 That is Sparkos Labs ebay store, they come direct from Andrew and shipping is only $6.00. He also takes offers for them, so you can hit him with a price and if it's close he will counter offer or accept.
  
 Just a suggestion, if you are just using the line out, pick up one and use it in the buffer/LPF socket which is only used for the line outs. That is how I started with the Sparkos
 by using I/V: LME49720 x 2
 LPF: Sparkos SS3602 descrete
 That setup got me to move to eventually to using all Sparko's duals in the STXII and the sound to me is incredible.
  
 Hope this helps and if you have any questions let me know...
  
 Ren


----------



## gr8soundz

Thanks for the reply.
  
 I'll be transferring my card to another, newer pc soon so I may wait to try the Sparkos once I remove the card.


----------



## dukefx

Did anyone experience harsh highs with V5i's in certain songs like Scorpions - Wind of change (mid part)?


----------



## igytech

Hi.Where to buy op amps in Europe? Thanks.


----------



## raoultrifan

In case you need SS V5/V5i you should purchase from Burson directly or from their eBay store, but also Audiophonics FR have some in stock. For MUSES get them from Profusion UK or Digikey or Mouser. General opamps could be bought from TME, Arrow, Digikey, Mouser, Farnell etc.


----------



## scruffy1

+1 : deal with burson directly (melbourne, australia)
  
 dennis is very helpful


----------



## scruffy1

gr8soundz said:


> Thanks for the reply.
> 
> I'll be transferring my card to another, newer pc soon so I may wait to try the Sparkos once I remove the card.


 
  
 i can't offer personal experience on the sparkos, but i can say substituting the v5i in the primary slot on my asus hdav1.3 was an epiphany for the small expense involved
  
 my advice is lash out and try that, and if you feel something has fundamentally changed in your listening experience, then the sparkos may well be worth taking a punt on
  
 i am tempted, but have other more pressing financial responsibilities at present, and in truth, am still in a state of awe and bliss whenever i switch on the sound system at home such that i am unable to even comprehend having something even more amazing to listen to than what has happened here
  
 beware ! the genie will not go back in the bottle once you start this magic


----------



## gr8soundz

Thanks for the info.
  
 Saw your posts in the STX thread too. Good to know the emi shield/cover still fits after swapping. Tight fit for the V5i but the Sparkos are even wider so not sure they are still an option.
  
 EDIT: Actually, it appears the Sparkos fit above the surrounding caps:
 http://sparkoslabs.com/discrete-op-amp-review-asus-xonar-stx-head-amp-card/
  





  
 Anyone know if the emi shield still fits after swapping to the Sparkos?


----------



## scruffy1

the opa627 i pulled to swap in the v5i sits similarly high, and the emi shield fitted, although i took the precaution of a layer of non-conducting (masking) tape under the shield in case of  possible shorting on the metal
  
 i noted only belatedly when i looked at the shield that it actually wasn't "tight" on one side where the op amp obviously pushed against it at the circular rim indented in the shield and was held from seating truly
  
 can't say i can hear any issue, and many people seem to leave the shield off without comment of it being detrimental


----------



## adydula

Just popped these new TI OPA1688's in an O2 to replace the 4556's...


----------



## Unclewall

I was planning to order some opa1688 next order, Im using opa1612  now and like the sound, What do you think of opa1688


----------



## adydula

I have three super Cmoys with this 1688 op amp installed, and they sound great.
 Check out:
  
 http://www.diyaudio.com/forums/headphone-systems/293247-opa1688-super-cmoy-2x-9v-real-ground-headphone-relay-pcbs.html
  
 and
  
 http://www.audiocircle.com/index.php?topic=142513.0
  
 and now this 1688's in the O2.
  
 I have compared to a stock O2, and an O2 with 827's in the O2 Booster Board from AGDR.
  
 They all do well, the 1688 has wonderful specs and is designed for headpone applications.
  
 To me it sounds more open and transparent...I hate using glittering generalities when trying to be objective about an analysis.
  
 Going back and forth between these I seem to gravitate to the O2 with the 1688's, bass seems absolutely solid.
  
 Its a simple and easy update. mouser sells the adapters and ICs;.
  
 Alex
  
 Note:
  
 Last week TI released a new audio Op Amp, the OPA1688 (http://www.ti.com/product/OPA1688)

 For those that are interested, the basic specs are:
 Gain Bandwidth Product: 10 MHz
 Slew Rate: 8 V/us
 Power supply voltage range: (4.5V to 36V or +/- 2.25V to +/- 18V)
 Power supply current: 1.6mA
 Input voltage noise: 8nV/rtHz (1kHz)
 Input current noise: 1.8 fA/rtHz
 Input offset voltage: +/- 0.25mV (typical)
 Input bias current: +/- 10pA
 Input voltage range: 100mV below V- to 2V below V+ (reduced specs outside of this range)

 What's really interesting about this device is the output stage linearity, which makes it a good choice for driving headphones. For example, if you're using an OPA2134 in a CMOY-type headphone amplifier, the OPA1688 would be a big improvement in both distortion and power consumption.


----------



## Unclewall

I have building agdr's super Cmoy amp on my list for when work slows down. If the opa1688 sounds like the opa1612 it should be a good amp


----------



## adydula

Its a good little amp!!
  
 The TPS3701 chip is a challenge to solder on the small pc board as well as the cap on the same board!
  
 It will test your soldering skills...I think AGDR is selling these with the chips mounted on them...you can contact hime at DIYAUDIO.com
  
 Alex


----------



## adydula




----------



## ph0n6

Just finished my review of the V5i, overall quite a good opamp: http://www.head-fi.org/products/burson-audio-supreme-sound-opamp-v5i/reviews/17179


----------



## raoultrifan

Very nice review, thanks!
  
 I've finished my tests and review with the V5i too, so for those interested in how V5i sounds in Low Pass and Voltage Amplification stages please have a read here: http://www.head-fi.org/t/784790/burson-supreme-sound-audio-v5-opa-d-v5-opa-s-review/120#post_12959395.


----------



## igytech

Can some one who use them compare OPA2227PA, LME49860NA and muses8920


----------



## raoultrifan

MUSES8920 is a FET-input opamp and may work different than the other 2, most likely in I/V stage could be better, after all it was designed to be used in I/V stage.

For low-pass and voltage-gain I would incline to OPA2227. To be honest, I'm not OK with the background of 49860 opamp when used in voltage-gain.

For buffer/output stage you could try any of them, just be sure will not oscillate.


----------



## vapman

Just replaced my portable amp (bMac 3CH MK2) Output Buffer Op-Amp JRC4556 with Burr Brown OPA2132PA. Right away noticing better soundstage, slightly recessed mids, and slightly brighter treble extension. will have to try OPA2132PA in place of the Gain Op-Amp NE5532, too.
  
  
  
  
 Would MUSES8920 be a good replacement for the gain op amp, and OPA2132 to output buffer?


----------



## adydula

Hey Guys,
  
 I was asked this question several post back and I got a reply from one of the actual TI Audio Engineers that is involved with this and other of the new TI op amps...feel free to contact him at DIYAUDIO.COM he is a wealth of technical information. 
  
 he is: johnc124

 Occupation
 Electrical Engineer: Precision analog semiconductor applications and new product definition

Country
 United States

Signature New Product Definition - Texas Instruments Precision Analog / Audio Products

  
  

 Originally Posted by *adydula* 
_Hey guys I got this question over at another forum:

 I really like your mod, but I'm worried about how the OPA1688 will handle output power under 32 ohms or even lower impedance headphones, because despite having the same mA output I see from the datasheet that can only handle 50mW/32ohms before clipping; for 2 paralleled opamp this would be 100mW/32ohms, so about 6 times less power than original 4556 opamps (please correct me if I'm wrong).

 I will most likely purchase a couple of OPA1688 opamps soon, because I'm very interested in final results, but meanwhile do you think you could please test output power of your modded O2 with OPA1688 as output buffer for 32ohms output resistance? Also, if you could somehow measure OPA1688 die temperature while doing this test it would be perfect.

 I only have used my 250 ohm T90's so far, I will try with lower impedance headphones and a thermocouple today.

 Ideas??

 Alex_

 

 Remember that power is current squared times resistance. The OPA1688 clips into 32 ohm loads when it hits its internal current limiting circuitry. 1 channel of an OPA1688 (1/2 the chip) will deliver 50mW into a 32 ohm load without clipping, which is about 40mArms. If you put both channels on the chip in parallel, the output current available doubles to 80mArms, which is ~205mW. 2 OPA1688 chips, with all 4 amplifiers in parallel would be 40mArms x 4 = 160mArms or 819.2mW.
 __________________
 New Product Definition - Texas Instruments Precision Analog / Audio Products


----------



## raoultrifan

vapman said:


> Just replaced my portable amp (bMac 3CH MK2) Output Buffer Op-Amp JRC4556 with Burr Brown OPA2132PA. Right away noticing better soundstage, slightly recessed mids, and slightly brighter treble extension. will have to try OPA2132PA in place of the Gain Op-Amp NE5532, too.
> 
> 
> 
> ...


 
  
 Well, I'm not sure OPA2132 was designed to be used as output buffers directly connected to headphones, though I don't know bMac's internal schematic. Technically speaking JRC4556 might be safer as output buffer I'd say. I would choose the OPA2132 for the gain stage instead, it has been proved it sounds very well in several headamps. MUSES8920 and also MUSES8820 should sound very well too in gain stage and their internal noise is lower then the NE5532, so feel free to give'em a try.


----------



## vapman

raoultrifan said:


> Well, I'm not sure OPA2132 was designed to be used as output buffers directly connected to headphones, though I don't know bMac's internal schematic. Technically speaking JRC4556 might be safer as output buffer I'd say. I would choose the OPA2132 for the gain stage instead, it has been proved it sounds very well in several headamps. MUSES8920 and also MUSES8820 should sound very well too in gain stage and their internal noise is lower then the NE5532, so feel free to give'em a try.


 
 Darn I need to stop writing posts before going to bed.
 You are right and the photo I posted showed my post you quoted was mixed up. The 2132 is in the gain stage in fact.


----------



## vapman

Sorry for a double post, but I'm looking at MUSES8820 opamps on eBay, and wondering if all the ones in China for under $20 shipped are fake or not?


----------



## raoultrifan

I suggest Mouser or similar stores for MUSES 8820 and you can also find OPA1688 and adapters for them, in case you feel like upgrading the output buffers (more about this http://www.head-fi.org/t/616331/o2-amp-odac/5205#post_12947025


----------



## vapman

raoultrifan said:


> I suggest Mouser or similar stores for MUSES 8820 and you van also find OPA1688 and adapters for them, in case you feel like upgrading the output buffers (more about thjis http://www.head-fi.org/t/616331/o2-amp-odac/5205#post_12947025


 

 Thanks a ton man, was just looking for more info on different output buffers, as I've only been messing with the gain stage so far. I have been checking out Mouser and Digikey and will probably use one of them soon to get a legitimate MUSES IC. Thanks so much!
  
 I would get a burson IC opamp but there is no way I could fit one of those in my tiny portable amp... however, I have room in my Technics stereo...


----------



## raoultrifan

I'm glad I could help. Anyway, the SS V5i might fit after all, try measuring the space from inside your amp and compare with V5i dimensions.
  
 Good luck!


----------



## dukefx

Use 13x13mm as measurement (as opposed to 11x11mm listed on the datasheet). When I measured mine I should have had 1mm left between the V5i and the nearest capacitor. In reality the V5i is pushing the cap away and barely fits.


----------



## RyokoZekem

I am using the LT1364 in my Little Dot i+ amp and its getting super hot. I am worried it will burn out early but would running it cooler with say a tiny heatsink and I do have a few, cause problems in the way it processes sound? Does an OPAMP running warm/hot cause different sound characteristics?


----------



## raoultrifan

Well, you're replacing a 16MHz-7V/uS opamp with a 70MHz-1000V/uS one, so it might oscillate, despite the recommendations from http://www.littledot.net/forum/viewtopic.php?t=385 for the LT1364 I strongly suggest you to get a scope and check for oscillations. Also, MC33078 has a max. recommended voltage of 36V (+/-18V) and LT1364 has only 30V (+/-15V), so it might worth checking the actual voltage on the opamp rails, just to be sure you're in the safe zone with the LT1364.
  
 You can also try the BURSON SS V5i that can tolerate even +/-16V, it was specifically designed for music and it also has a metallic case for a better shielding and thermal transfer, but also MUSES8820 or the more expensive MUSES02 might be a good upgrade for the MC33078.
  
 Please, do understand that the sound gets created inside this opamp which is named Voltage Gain or Voltage Amplification Stage and all the micro-details and soundstage get created in here. The final tubes are the buffers that takes care of final warmth and final character of the sound and also handling the distortions very well. Using an opamp dedicated for music will give you a very high probability to get a very good sound without being worried of oscillations or heat issues (at least in most cases).
  
 Good luck!


----------



## RyokoZekem

I had a feeling that the OPAMP might be an issue but I don't have a scope or the skills to use one to test it. I think I'll get a Burson to replace it just to be safe and feel confident there are no issues. The sound of the LT1364 is quite nice but if its causing damage to my equipment possibly I'm not too keen on that.

 As for the Burson, is the tall one better and if so, is using an extender a bad thing to fit it inside the case?

 Thank you for the reply.


----------



## raoultrifan

Hi, 
  
 I would not recommend an extender, instead you could use 2xDIP8 adapters to increase the height, in case this helps somehow.
 You should consider a 13x13mm for the SS V5i to properly fit in there, maybe some pictures will help.
  
 Regards!


----------



## RyokoZekem

Alright I'll just get the V5i. Thanks a lot.


----------



## Faber65

ryokozekem said:


> Alright I'll just get the V5i. Thanks a lot.




Enjoy!


----------



## Lohb

Anyone know how MUSE 01/02 compares against AD797s ?


----------



## bnsb

Quote:Originally Posted by *scruffy1* /img/forum/go_quote.gif
   i have now had a mere two days of using the burson v5i
  
 it replaced a dual opa627 in the buffer position on my asus xonar hdav1.3, that was initially occupied by the stock supplied (LM)4562NA
  
 having decided in short order that the opa627 was an improvement on the 4562na i never changed it out in half a decade because it seemed clear to me that opa627 was better at "tight" bass and general all round reproduction
  
 until wednesday afternoon...  when i discovered how the burson v5i compares
  
 in a word : better
 in more words : n(much) better
 -----
  
  
 Any idea about size/dimension of the V5i, I mean the length breadth, and more importantly height.  Can these be used in DAP like Fiio AMP1 module. Thanks


----------



## tl13m

> Any idea about size/dimension of the V5i, I mean the length breadth, and more importantly height.  Can these be used in DAP like Fiio AMP1 module. Thanks


 
  
 From the Burson website, V5i size: W 11 D 11 H 7.3
  
 It's like 2x size normal op-amp.


----------



## dukefx

tl13m said:


> > Any idea about size/dimension of the V5i, I mean the length breadth, and more importantly height.  Can these be used in DAP like Fiio AMP1 module. Thanks
> 
> 
> 
> ...


 
 Check the previous page, d'uh.


----------



## Audio Addict

dukefx said:


> Check the previous page, d'uh.




My 4 singles arrived today. I will first try them in the Lycan and then ultimately my Apache.


----------



## shyamelge

Today I was swapping op amps in asus essence one amp. 
  
 I noticed that LME 49990 get very hot in I/V and LPF sections but in HP and RCA buffers they run coolly.


----------



## pelopidas

Try putting a capacitor across the power pins. That may do the trick.


----------



## gr8soundz

Just posted my first review on head-fi for the Burson V5i opamps:
 http://www.head-fi.org/products/burson-audio-supreme-sound-opamp-v5i/reviews/17382


----------



## afshin

Hi all
  
 Last month I recieved Burson V5i dual opamp product for testing.
 First of all, a big thanks to bursun audio especially *Charles* that provide this chip to me for testing.
 I tested this product and then sent it to my friend to have his expriences.
  

  
  

  
  
  

 Our tests, me and my friend, are carried under different conditions, with different components and different wires, I Use *silver-plated* wire and my friend have *copper* one
 These results are obtained when *break-in time* passed and sound became stable
 These are our impressions that bothly agree with, in spite of diferrent testing condition that we have.
  
 at first I put this chip in input stage of my amplifier and encounter with tempreture rising of chip, it reached aproximately up to 75 degree celsius, really hot, and sound became distorted
 I emailed to burson and they said this situation is not normal and may be due to weak connection..
 anyway, I got rid of this problem and my friend didn't have any issue with implementing this chip.
  

  *Compare the heat 627 :*

  

  
  
  
  
  
 We think this is a *high resolution* chip. Sound is *dynamic* especially in* vocal*.
 So *soft* sounding chip that fits for long listening without fatigue.
 In terms of sound stage, we believe this chip has *soundstage*, best part of staging in this chip is percepted at mid-range but soundstage at mid bass range is crowded and messy.
 Low frequency is back-bone of staging and any flaw in this range could have defect in sound image.
 When chip is cold, it sounds more organic and soft, stage at mid bass is acceptable, mid bass is punchy, vocal is a little backward and high range is a bit polished and soft but after the chip is warmed up low frequencies become a bit messy, vocals become more clear and in position and high range become more powerfull, sterile and clinical.
 In spite of using ceramic caps, we didn't find any *piezo effect* on sound.!!! This is very  good. 
*TDK* ceramic is good, but we intrested in *film* *capacitors*, *Vintage* and *Vinyl *Style 
 This is a high class chip with clear sound, details especially in mid-rang is very dynamic and enjoyable.
  

 Best regards,
 Afshin


----------



## vapman

What is a suitable replacement for *JRC2114D?*
  
 I just bought a X-Fi Titanium HD. Was thinking about a NE5532, then saw it was dual opamps. not sure what to use!


----------



## raoultrifan

MUSES8820 > JRC2114D > NJM5532 > NE5532
  
 If you got the money you might want to try MUSES02 and BURSON V5i or even SS V5 too if have enough space for it.


----------



## vapman

raoultrifan said:


> MUSES8820 > JRC2114D > NJM5532 > NE5532
> 
> If you got the money you might want to try MUSES02 and BURSON V5i or even SS V5 too if have enough space for it.


 
 I have two Burson V5i on the way because of all the hype! But they are stereo opamps and I assume I need two mono opamps to replace the 2114D?
  
 I am certainly open to trying muses 8820 but I know I like the mid forward, neutralish sound of NE5532.
  
 edit: Nevermind. Seems the 2114D is a dual opamp too so I could use both my Burson in it.


----------



## raoultrifan

http://www.njr.com/semicon/PDF/NJM2114_E.pdf - looks are stereo.


----------



## vapman

raoultrifan said:


> http://www.njr.com/semicon/PDF/NJM2114_E.pdf - looks are stereo.


 
 Yup, you are right! 
 So i will get some new dual opamps for my X-Fi.
  
 for me soundstage, neutral sound & lots of bass is what i am after...


----------



## Lohb

Any suggestions please for something like AD797 with more bass weight and not as bright up top ?


----------



## Charminbaer

lohb said:


> Any suggestions please for something like AD797 with more bass weight and not as bright up top ?


 
  
 Use AD797 BRZ and add 50pf silvermica caps to the compensation circuit.
 Additionally decouple powerrails with 100nf ceramics and 470uf Panasonic FM electolytes.
  
 That should give you a big soundstage and very good deep bass reproduction without brightness. Provided your circuit isnt oscillating. Brightness with the AD797BRs is usually a sign of instability.
  
 I had two AD797BRZs on a DIYinHK SOICtoDIP Adapter with those measures taken in my Auzentech X-Fi Prelude without Problems and a superb sonic performance.


----------



## pelopidas

Panasonic fm is not an audio grade capacitor. It does not have a big soundstage and it produces an unpleasant treble that some mistake for detail. AD797BRZ is a nice opamp and deserves better than a Panasonic FM. Elna Silmic is the best imo and 10uf is enough. If it is unstable in your circuit try the comp capacitor but if it is stable then run it wide open. 
Lme49990 is another good opamp.


----------



## afshin

In all my test Silver Mica caps piezoelectric effect was intense!


----------



## vapman

Seconding Panasonic FM being unpleasantly bright, I restored a NAD amp with those caps and was unhappy with how bright it had become.
  
  
 Just swapped 2x NE5532 into my Creative X-Fi Titanium HD... it sounds awesome. nice and clear and neutral but with good tight bass.


----------



## Charminbaer

pelopidas said:


> Panasonic fm is not an audio grade capacitor. It does not have a big soundstage and it produces an unpleasant treble that some mistake for detail. AD797BRZ is a nice opamp and deserves better than a Panasonic FM. Elna Silmic is the best imo and 10uf is enough. If it is unstable in your circuit try the comp capacitor but if it is stable then run it wide open.
> Lme49990 is another good opamp.


 
 I have not experienced any treble harshness with Pana FMs so far. FCs on the other hand are a little on the bright side. But I am talking about them beeing for powersupply decoupling not directly in the signalpath.Unfortunately I never had the opportunity to test Elna Silmics.
  
 I have found Nichicon KZ caps to be very good as well. Better than Pana FMs but also a lot pricier.
  
 As for their size, 10uf was too little in my circuit. 200uf+ definitely improved things for me. But that is for my X-Fi in a PC, which naturally has a lot more noise than most audioequipment (including low frequency noise from fans, HDDs and other motororized parts).
  
  
 Sorry I did confuse the distortion cancellation circuit with compensation circuit. I would let the AD797BRZ run open without compensation cap too. But I found its sonic performance to increase by adding a 50pf cap (between pin 8 and output) to its distortion cancellation circuit.
  


afshin said:


> In all my test Silver Mica caps piezoelectric effect was intense!


 
  
 It doesn´t necessarily has to be a silvermica, any linear capacitor suited for beeing in the signalpath should do fine.


----------



## vapman

charminbaer said:


> As for their size, 10uf was too little in my circuit. 200uf+ definitely improved things for me. But that is for my X-Fi in a PC, which naturally has a lot more noise than most audioequipment (including low frequency noise from fans, HDDs and other motororized parts).


 
 I have been wanting to recap my X-Fi Titanium HD.  Did you recap a PCI/PCIe X-Fi or external?
  
 My computer is such a noisy mess... I am surprised the X-Fi is as quiet as it usually is.


----------



## Charminbaer

Yes I did a full recap of the powerfiltering section of a PCI X-Fi (Auzentech Prelude) with 100uf Nichicon KZs and one big 820uf Panasonic FM. All Electolytes bypassed by 100nf Polystyrene. Would have liked something better than Polystyrene but i couldn´t get my hands on anything at the time.
  
 Additionally i attached 470uf Nichicon KZs and 100nf ceramics as close as possible to each powerrail on the SOICtoDIP adapter.
  
 I too am suprised that it sounds as clean as it does. The Recap did help a lot in that regard though.


----------



## raoultrifan

pelopidas said:


> Panasonic fm is not an audio grade capacitor. It does not have a big soundstage and it produces an unpleasant treble that some mistake for detail. AD797BRZ is a nice opamp and deserves better than a Panasonic FM. Elna Silmic is the best imo and 10uf is enough. If it is unstable in your circuit try the comp capacitor but if it is stable then run it wide open.
> Lme49990 is another good opamp.


 
 Hi, 
  
 If used in signal path then a capacitor indeed needs to be dedicated for audio use, otherwise you should only care about ripple and noise suppression, so I really don't think it matters much if Elna Silmic or Panasonic FM if used for decoupling (I would care more about the no. of hours that cap was designed to be used for). Basically, a very good low-noise power source is a must in Hi-Fi world, but for opamps decoupling a small and very fast ceramic capacitor of 0.1uF (for fast transients) and a low-ESR 10uF tantalum or 100uF electrolytic should be more than enough for decoupling (http://www.analog.com/media/en/training-seminars/tutorials/MT-101.pdf, http://www.partsconnexion.com/PDF/mulcap-ps.pdf, http://www.capacitorguide.com/coupling-and-decoupling/).
  
 If sound is indeed changing when switching between different decoupling caps then using a scope might see this difference, so either the opamp is or is not oscillating anymore, either the ripple and noise on opamp V+/V- is indeed different (depending on the caps used, one specific cap might perform better than another under some circumstances).
  
 When used in signal path, then "best cap is no cap", so DC servo and a simple "wire" would be better, if possible. Otherwise, we all need to stick to the best audio cap we can purchase, that means very low: dissipation factor, dielectric absorption, low inductance, ESR etc. ()


----------



## pelopidas

Hi raoultrifan

I used to think that there is a strict separation between signal path and power supply side too. However this just is not the case. 
To put it in cooking terms, the circuit is the recipe but the power supply is the ingredients. 
If the recipe calls for carrots you can used canned or frozen or you could use garden fresh. The ingredients absolutely matter even though the dish is technically the same. 
Just put a Jamicon in your decoupling positions and tell me it is glorious. 
Every single capacitor in every single position has an effect.


----------



## 37mil

pelopidas said:


> Hi raoultrifan
> 
> I used to think that there is a strict separation between signal path and power supply side too. However this just is not the case.
> To put it in cooking terms, the circuit is the recipe but the power supply is the ingredients.
> ...


 

 Exactly right. Considering the electricity from the power supply is the main ingredient that is transformed into the signal downstream, the power supply and associated capacitors are all part of the signal path.
  
 In my Teac UD-501 I upgraded all the 'signal' caps to silmics which I'm a fan off. However, when I installed Dexa voltage regulators, the sound was astonishingly BAD. Bass heavy and muddled. It was then I consulted with the designer of the dexa's who told me to remove the regulator output caps (the silmics) either completely or replace with film. I replaced with film and this, together with sparko's op amps, transformed the dac into the most transparent and dynamic i've ever had.
  
 Incidentally, Burson have supplied me with some v5i's to try, which I have in place of the sparko's at the filter position and I find them bass heavy with the treble rolled off. There is also a pronounced peak in the mid bass region which is bad for some male vocals. Overall the effect is a much narrower soundstage.


----------



## pelopidas

I agree about the V5i being pretty terrible until thoroughly burned in. My experience was the same with them being bloated in the bass and muddled treble. Waiting for them to burn in was worse than almost any other component I have tried. But once burnt in they are better than any chip opamp. Give them a minimum of 100 hours and then listen critically again. They are not as good as V5 but better than any other chip I have tried


----------



## 37mil

i burned the v5i for over 100 hours but couldn't bear any more. It was just not working out. It definitely does sound like a chip amp. Compared to discrete, it's left in the dust. The original, yellow, v5 were magnificent followed closely by sparkos.


----------



## pelopidas

Agreed. Compared to the discreet they are just chip opamps. After going discreet it is actually impossible to go back to chips. I am stuck on the V5 and have no upgrade path left. 
My next project is to build a better headphone amp. Then what?


----------



## Lohb

Yes, I just did not like the v5i, too thin-sounding/analytic and difficult to fit.
 They can bring things back with a V6 though...the best companies pivot fast.
  
 Was there any reason the V5 needed that red cover ? Were they that susceptible to EMI or similar ?


----------



## palermo

I did some experiment to my D14 ibasso, swap the stock opamp as LPF (OPA1602) with Muses8920E. It give more separate instrument, forward but warmish sound. D14 turn to darker signature that couldn't please me. Then I look at amp stage opamp, no label on it, so I replace it to AD8599. overall it sounds good for pop and acoustics like stockfish record but lack for metal genre.


----------



## dukefx

I had the exact same experience with the V5i. It was unbearable at first and took about 40 hours to burn in. I was shocked when someone a few pages back said theirs sounded good right out of the box. Analytical/thin? No, quite the contrary, It was rather tubelike (which I'm not a fan of). I finally settled for the Sparkos which provides the most natural and realistic sound (in the O2 with my K712s).


----------



## 37mil

dukefx said:


> I had the exact same experience with the V5i. It was unbearable at first and took about 40 hours to burn in. I was shocked when someone a few pages back said theirs sounded good right out of the box. Analytical/thin? No, quite the contrary, It was rather tubelike (which I'm not a fan of). I finally settled for the Sparkos which provides the most natural and realistic sound (in the O2 with my K712s).


 

 exactly my findings as well. Definitely not thin, the bloated bass and reduced treble saw to that. I'm loving the sparkos, been in my dac a long time now.


----------



## Charminbaer

raoultrifan said:


> Hi,
> 
> If used in signal path then a capacitor indeed needs to be dedicated for audio use, otherwise you should only care about ripple and noise suppression, so I really don't think it matters much if Elna Silmic or Panasonic FM if used for decoupling (I would care more about the no. of hours that cap was designed to be used for). Basically, a very good low-noise power source is a must in Hi-Fi world, but for opamps decoupling a small and very fast ceramic capacitor of 0.1uF (for fast transients) and a low-ESR 10uF tantalum or 100uF electrolytic should be more than enough for decoupling (http://www.analog.com/media/en/training-seminars/tutorials/MT-101.pdf, http://www.partsconnexion.com/PDF/mulcap-ps.pdf, http://www.capacitorguide.com/coupling-and-decoupling/).
> 
> ...


 
  
 Exactly my thoughts as well. But in my experience good electolytics with more than 200uf provide better low frequency filtering.
  
 As for the signal path no cap indeed is the best cap but unfortunately not always possible. At least not for a manufacturer.
 I found NIOB-OXIDE caps to be quite nice in the signal path. Especially if one needs bigger values like 1-50uf, their price to performance ratio is very good compared to PPs or Teflon.


----------



## dukefx

> I found NIOB-OXIDE caps to be quite nice in the signal path.


 
 Niob caps tend to have an extremely low Voltage rating, usually <10V


----------



## Charminbaer

dukefx said:


> Niob caps tend to have an extremely low Voltage rating, usually <10V


 
 For signalpath use that is no problem. 6V should be sufficient.


----------



## raoultrifan

They really need to be able to block an entire DC-rail, so if your amplifier is operating at +/-12V then the capacitor used in signal path should be able to handle at least 12V, so most likely 16V DC would be the minimum DC voltage for the capacitor you're looking for.


----------



## Charminbaer

raoultrifan said:


> They really need to be able to block an entire DC-rail, so if your amplifier is operating at +/-12V then the capacitor used in signal path should be able to handle at least 12V, so most likely 16V DC would be the minimum DC voltage for the capacitor you're looking for.


 
 Okay i didn´t know that, thanks for the info. I thought it only needed as much as double the signal strength.
  
 Isn´t DC Bias normally in the mV range though?


----------



## raoultrifan

You need a capacitor in signal path to filter any possible DC voltage that may come from the input source. Imagine that an opamp, somewhere before the capacitor, will get defective and will get the entire DC voltage to its output pins, then the capacitor needs to handle/filter this DC voltage. http://sound.whsites.net/articles/coupling-caps.htm#p20 would be a good reading.
  
 Also, worth reading: www.partsconnexion.com/PDF/mulcap-ps.pdf and http://www.capacitorguide.com/coupling-and-decoupling/ too.
  
 Some examples:
 - ASUS Essence One DAC has coupling capacitors on it's output RCA and XLR plugs, so in case an internal opamp gets burned, then the DC-voltage will not destroy a possible connected external amplifier. Instead, for its internal headphone amplifier it has no caps in signal path, because it uses DC-servo to get rid of any possible DC-voltage on headphones output.
 - Matrix M-Stage HPA-3B amplifier has 4 x input caps, just in case some defective DAC will get connected. Even a DAC having 10mV DC-voltage on its outputs, when connected to a high gain +20dB amplifier will get a 0.1V on headphone outputs, which is quite high DC, even for low-sensitivity cans.
 - Objective2 has 2 x input caps too, to protect headphones


----------



## ph0n6

Has anyone bought the LME49600 from this ebay guy before:
 http://www.ebay.com/itm/1PCS-LME49600TS-LME49600-ON-DIP-ADPTER-REPLACE-BUF634-/321270074527
 Kinda need a pair for replacing mine BUF634 in the P5. The seller have fine ratings, but Chinese ebay are infamous for their counterfeit so......


----------



## northendjazz

@ph0n6 yep I bought some earlier this year from this seller, no problems for me. I enjoyed them in my ibasso p4.


----------



## Charminbaer

raoultrifan said:


> You need a capacitor in signal path to filter any possible DC voltage that may come from the input source. Imagine that an opamp, somewhere before the capacitor, will get defective and will get the entire DC voltage to its output pins, then the capacitor needs to handle/filter this DC voltage. http://sound.whsites.net/articles/coupling-caps.htm#p20 would be a good reading.
> 
> Also, worth reading: www.partsconnexion.com/PDF/mulcap-ps.pdf and http://www.capacitorguide.com/coupling-and-decoupling/ too.
> 
> ...


 
  
 Thank you for the informative links. 
	

	
	
		
		

		
			




 So it´s more of a safety measure than a purely functional one.
  
 I looked up the specifications from AVX which is the manufacturer of my Niob caps. It seems that Niob caps are very hard to short circuit due to dielectric breakdown. It needs greater than 4 times the rated voltage to get it to short circuit.
  
 My caps are rated 10V and my power rails +-12V. If I understood this correctly it basically needs approx. 40V of DC to kill anything behind them.
 I find that very unlikely in computers since they use no voltage greater than 12V. As for other sorts of equipment that could of course happen.
 And I assume it would have a negative impact on soundquality if the dielectric barrier broke down even if not short circuited.
  
  


> As a result the capacitor is not likely to create a short circuit after the main Nb2O5 dielectric breakdown, but keeps a high resistance around 34kOhms typically – see Fig.6 with comparison of resistance after breakdown on tantalum polymer, aluminum polymer and NbO capacitors. It can be noted externally as just a slight increase of leakage current, and otherwise the capacitor keeps working.
> 
> Thus within its rated voltage the NbO OxiCapTM capacitor is not likely to fail as a short circuit in applications. The capacitor can be thermally damaged only when used outside the specifications such as over-voltage breakdown (> ~ 4 times rated voltage), reverse voltage, excessive ripple current and high acceleration of temperature with voltage.
> 
> ...


----------



## dukefx

> I find that very unlikely in computers since they use no voltage greater than 12V.


 
 Unless you anger the almighty Zeus


----------



## adydula

The 827 is in AGDR audios O2 Booster Board, I built one this year and its a great! Alex


----------



## Charminbaer

dukefx said:


> Unless you anger the almighty Zeus


----------



## notamethlab

Anyone know of a seller that has authentic MUSES01/02 on ebay? They've gotten very expensive on mouser.


----------



## igytech

notamethlab said:


> Anyone know of a seller that has authentic MUSES01/02 on ebay? They've gotten very expensive on mouser.




You don't have cheap authentic even on ebay. And still you can't be 100% shure with that sellers.


----------



## raoultrifan

Like igytech said, stay away of eBay, because all most sellers are selling fake MUSES only. Better get 8820/8920 if you don't want to spend money on 01/02 right now. 8820 is having a good price for a wire with gain chip, same applies for 8920 if you need a decent opamp for I/V stage.
  
 BTW, I purchased 10 x MUSES (8x01 & 2x02) directly from the UK NJR supplier PROFUSION PLC; a little bit cheaper than Mouser. I also got some 8820 & 8920 from them and I was pleased with their services.


----------



## notamethlab

Thanks for the help! I'll just wait until either one of them drops in price or until the release of the MUSES03, I'm not in a hurry to get them.


----------



## gr8soundz

raoultrifan said:


> Like igytech said, stay away of eBay, because all sellers are selling fake MUSES only. Better get 8820/8920 if you don't want to spend money on 01/02 right now. 8820 is having a good price for a wire with gain chip, same applies for 8920 if you need a decent opamp for I/V stage.
> 
> BTW, I purchased 10 x MUSES (8x01 & 2x02) directly from the UK NJR supplier PROFUSION PLC; a little bit cheaper than Mouser. I also got some 8820 & 8920 from them and I was pleased with their services.


 
  
 I was also trying to decipher which ones on ebay are fake. Haven't brought an 02 yet (since the V5i is too tall for my portable amp). Will probably get one from Mouser to be on the safe side (too bad they don't sell on ebay).
  


notamethlab said:


> Thanks for the help! I'll just wait until either one of them drops in price or until the release of the MUSES03, I'm not in a hurry to get them.


 
  
 That was my thinking as well until someone pointed out the 03 will be single channel only, not a dual opamp like the 02.
 http://www.head-fi.org/t/826344/muses03#post_13024829


----------



## raoultrifan

notamethlab said:


> Thanks for the help! I'll just wait until either one of them drops in price or until the release of the MUSES03, I'm not in a hurry to get them.


 
 I believe MUSES03 would be single opamp, not dual like MUSES01. Anyway, MUSES03 was designed for I/V convertors, so it should be perfect for DAC's I/V stages.
  


gr8soundz said:


> I was also trying to decipher which ones on ebay are fake. Haven't brought an 02 yet (since the V5i is too tall for my portable amp). Will probably get one from Mouser to be on the safe side (too bad they don't sell on ebay).
> 
> 
> That was my thinking as well until someone pointed out the 03 will be single channel only, not a dual opamp like the 02.
> http://www.head-fi.org/t/826344/muses03#post_13024829


 
 I believe it was a thread here on Head-Fi, but usually you need to analyze the picture with front of the opamp. Also, see the edges, should be a bit rounded and not sharp; they usually take the cheapest opamp, polish the surface and laser/print the MUSES on front, this is why from the polish the edges become a bit sharp...like 90 degrees sharp. Also, the final test would be their legs, that are way much softer than a regular opamp, perhaps too much copper inside (perhaps silver too?). Last one: now most eBay sellers are using original MUSES pictures, so you can't even identify that they're selling fakes anymore.


----------



## notamethlab

raoultrifan said:


> I believe MUSES03 would be single opamp, not dual like MUSES01. Anyway, MUSES03 was designed for I/V convertors, so it should be perfect for DAC's I/V stages.
> 
> I believe it was a thread here on Head-Fi, but usually you need to analyze the picture with front of the opamp. Also, see the edges, should be a bit rounded and not sharp; they usually take the cheapest opamp, polish the surface and laser/print the MUSES on front, this is why from the polish the edges become a bit sharp...like 90 degrees sharp. Also, the final test would be their legs, that are way much softer than a regular opamp, perhaps too much copper inside (perhaps silver too?). Last one: now most eBay sellers are using original MUSES pictures, so you can't even identify that they're selling fakes anymore.




Thanks for that I guess I have to wait for it to drop in price at mouser, it's currently at $49. It was $30 a couple of weeks ago.


----------



## santodx5

Hi all,

I have XTA 446 sound management module. It has 15 opamps (NE5532) inside. I never replace opamp before and have been reading forum like crazy to find the best opamp for me.

Some people mention Sonic Imagery 994Enh-Ticha Dual Discrete Opamp to be the best one but why no one discuss it here?

Hope someone can give some feedback.

So far im thinking to use 6 discrete opamps in the output and use Burson V5i for the rest. Replacing all with discrete will certainly kill the power supply. Here is the xta board hope someone can give me some guides as im new to this. According to XTA, the unit supplies -15v -+15v but i have no idea the current for each opamp.

Thanks.


----------



## dukefx

I've seen that one on ebay, but I don't know anything about it.


----------



## raoultrifan

Sonic Imagery 994Enh-Ticha costs almost 100 USD/each, so its all about how much money do you really want to spend here. There are posts about this opamp on HeadFi, some use these in I/V, some in LPF with great success.
  
 V5i needs to be tested first, hope you can find a couple to borrow or purchase just 2-3 firstly, so you can test'em for compatibility, then purchase the rest. If SS V5 fits the case and the bill, then you might want to give'em a try too.
  
 MUSES8820 is also a good upgrade for NE5532 (8820 is a low noise wire with gain opamp); MUSES02 too, if money's not a problem.
  
 Usually MUSES8820 and MUSES02 are not prone to oscillations, so you can purchase all quantity you need without worries.


----------



## santodx5

Hi,
  
 Money is not a problem here as I want the best possible upgrade.
  
 I found only a few Sonic review but it is pretty vague. Can you link me more?
  
 Replacing all 15 opamp will not be possible because it will put strain in the PSU and possibly will damage it, so I need to mix some opamp.
  
 The manufacture does recommend Muse 8920 but all the review here states that V5i / V5 is better than any Muse.
  
 I will replace all the caps with Audinote Note Kaisei or Slimic II or Nichicon KZ where it fits as well.
  
 Thanks


----------



## raoultrifan

The original NE5532 is a bipolar-input opamp, like with MUSES8220, this is why I think this might be a good upgrade. Anyway, per manufacturer recommendation, MUSES8920 are low noise and very good opamps and for their price you can easily upgrade all 15 opamps. No worries about the PSU, as long as opamps are not oscillating you should be just fine.
  
 Your picture is not very clear, can you please do another picture so we can all see all the opamps (what's written on them) and how devices are arranged?
 Right now, if I see correctly, on the left side there are 3xPCM1794 DACs, each one followed by 2 x opamps used in I/V (the soldered on the PCB, SO8 opamps, perhaps singles not duals), 1 x opamp for LowPassFilter (NE5532 I believe) and 2 x opamps as buffers (aren't these NE5534?).
 On the right side there might be the ADC part, right?
  
 P.S.: You might also want to google-translate this: http://forum.audiofanatyk.pl/index.php?/topic/18-sonic-imagery-labs-994enh-ticha/.


----------



## santodx5

Helo,
  
 Here are some new photos:
  
 https://s27.postimg.org/qo4b6k7qb/20161224_001950_resized_1.jpg
 https://s27.postimg.org/ov1ei8mjn/Picture_20164928064949_resized_2.jpg
  
 There are 15 opamps and they are all NE5532.
  
 Right now I am waiting to test the PSU if I can use all class A opamp.
  
 I read the link about Sonic Imagery but only a few post, hope someone else can give more feedback. It is the only discrete opamp that gives complete specs and test in the market but very few review so far.
  
 Someone recommends LME 49720N in the line driver ( 6 near the caps), I am not knowledgeable about opamps, hope someone can give some advice.
  
 Thanks


----------



## raoultrifan

I still like the old photo better, sorry. 
 I need a photo from where I can actually see the PCB traces and also what's written on opamps (inlcuding the soldered opamps too).
  
 Meanwhile, I still think that on the left side there are 3 x PCM1794 DACs, each one followed by 2 x opamps used in I/V (the ones soldered on the PCB, SO8 type, perhaps NE5532 too), 1 x opamp for LowPassFilter (NE5532) and 2 x opamps used as buffers (NE5532). That means you can only upgrade with ease the 3 x opamps from each DAC and here's what I would suggest, in order of price: MUSES8820, MUSES02, BURSON V5i, BURSON SS V5, Sonic Imagery 994Enh-Ticha.
  
 You contact Sonic Imagery and ask for their opinion about what you intend to do, maybe they'll tell you if their opamps are good for your application or not (I'm pretty sure they'll say YES).
  
 Anyway, the most important would be the I/V part, but you need an electronics guy to help you out removing the soldered opamps and installing different opamps in there (perhaps MUSES01 via SO8 to DIP8 adapter, if possible, or just solder MUSES8920 in SO8 package already available; for faster opamps you might need additional decoupling caps and also an oscilloscope to test for unwanted oscillations). 
  
 On the right side there might be the ADC part and you can use any of the opamps from above.


----------



## santodx5

Here you go again 
  
 They are all use DIP socket, no soldered connection.
  
 https://s5.postimg.org/do7bnrulj/20170105_004644_resized.jpg
 https://s5.postimg.org/69hzve8pz/20170105_004801_resized.jpg
 https://s5.postimg.org/4rwjju3zb/20170105_004808_resized.jpg
 https://s5.postimg.org/3ocf7vjc7/20170105_004812_resized.jpg
  
 Btw why dont you mention Sparkos in your list? It is considered better than V5. V5 will not fit in my case so it is out of my list.


----------



## raoultrifan

OK, I think I got what those SO8 opamps are for: voltage comparators
  
 So, schematic is quite simple,is actually the default one from TI's datasheet: first DIP8 opamp after the PCM1794 DAC takes care of I/V and the next 2 DIP8 opamps are dealing with LowPassFilter and output buffer too.
  
 I/V: MUSES01 or MUSES8920
 LPF: BURSON SS V5, BURSON V5i, MUSES02, MUSES8920.
  
 I'm sure Sparkos are better than any of the above opamps, but never tried them and I'm not sure the default decoupling caps (2 x 1uF) are enough; also, this might apply to BURSON SS V5 too (please use a scope to check for oscillations). I do not have experience with Sparkos, so please forward the pictures to Sparko Labs and they'll analyze if the default 2 x 1uF caps are OK for their opamps and if they recommend you to use'em in both I/V and LPF.
  
 For the ADC part, fell free to use any of the above opamps, but purely based on the specs, I'd vote for the Sparkos because are having the lowest noise possible. You should also check Sparkos dimension before ordering, to see if they can properly fit in there.
  
 Good luck and keep us posted, pictures too!


----------



## dukefx

A few things to keep in mind that might help:
  
 The SI opamps are huge (wide) and probably won't fit, no idea how they sound, never had one.
 I wouldn't really recommend V5i unless you like bloated bass. Mids and highs are nice and clear. No idea about its big brother. Raul can probably compare them. Fitting can be done with right angle DIP sockets if height is an issue. Aries and Mill-Max manufacture such.
 Sparkos opamps sound realistic while the V5i reminds me of tube amps.
 If you want to use Silmics, better double check space as they tend to be bigger than most other caps.


----------



## santodx5

Hello,
  
 Slimic will fit but I want to use Nichicon ES or AN Kaisei bipolar but they are too big.
  
 My plan so far is to use 3 SI for I/V (the only place that will fit) and Sparkos for others.
  
 @ raoultrifan The decoupling caps 1uf, do you mean the blue caps near the output? They are 220uf 35v that I will replace with slimic II.
  
 I dont have a scope or know how to use it Hopefully all will work plug and play.
  
 I will post review later. The original XTA already sounds really nice. I'm exciting how 15 discrete opamps will change the SQ.
  
 Thanks


----------



## raoultrifan

I meant the non-polarised rectangular grey caps nearby the DIP8 I/V opamps (you also need to double check this yourself by following PCB traces and comparing if these caps are connected between V+/V- pins and GND). The big blue caps should be output audio caps for lowering DC output (if any). Instead ES I'd vote for the KA, but feel free to read their datasheets and compare. Anyway before upgrading the big blue output caps feel free to short-circuit them for good with some short wires ("best cap is no cap") and see if something got improved (measure the DC output prior to connect the XLR plugs to an amp and if DC output is higher than 5mV maybe you should check if the connected amp has DC-servo or DC protection caps in input/output signal path!); if nothing got improved, then don't bother upgrading these caps.
  
 For the opamp decoupling I'd vote for 10uF/35V tantalum caps + 1uF+ 0.1 MLCC, if possible for both I/V and LPF stages (at least for the I/V). If do you intend to use only MUSES then existing decoupling might suffice. Anyway, sometimes wrong caps might do more wrong than good, so please use a scope if you intend to change decoupling caps (https://www.baldengineer.com/a-1uf-decoupling-capacitor-is-too-much.html).
  
 If you don't want to bother with scope and soldering parts, just get the MUSES01 for the I/V and try a couple of BURSON V5i in LPF; check for overheating and if everything seems fine then purchase the remaining opamps. BTW, what's the voltage on V+/V- for these opamps, please?


----------



## santodx5

15+ - 15- is the voltage.


----------



## viivo

Figured it would be better to ask here than start a new thread.

Paste of the question I posted elsewhere:

"Replacing a dual op-amp with a single?

No doubt this is a simple question, but as I know nothing on the subject and found nothing from searching, I have to ask.

My motherboard (Gigabyte z170x Gaming-7) came with an OPA2134 as part of the onboard audio's headphone amplifier. For one reason or another, the one on mine has departed this mortal coil and must be replaced. The only other op-amp in my posession is the OPA134. Would there be any issues using it? There is also a gain switch for the amp on the motherboard with two settings - x1.5 and x7.5 - so I'm wondering if the single would work with the switch left at the lowest setting. Or are the pin-outs too different?

Thanks for any help."


----------



## ph0n6

You could buy a single to dual opamp adapter, don't plug in single to dual, you might ended up with a burnt opamp or even components.
 https://www.google.com/search?q=dual+to+single+adapter+opamp&client=firefox-b-ab&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiMgOmGnq_RAhWJQpQKHU7eCmEQ_AUICCgB&biw=1280&bih=649#imgrc=_


----------



## raoultrifan

santodx5 said:


> 15+ - 15- is the voltage.


 
  
 This is would be the maximum voltage for SS V5, but they should be fine if there's enough room for ventilation inside the case. MUSES should be fine too (their max. voltage is +/-18V). Sonic Imagery 994Enh-Ticha and the Sparkos SS 3602 are also fine too (in case you can fit some of these inside the case).
  
 BTW, is you can fit 994Enh-Ticha in the I/V stage you might give them a try, but it worth chatting with someone from Sonic Imagery if existing decoupling would suffice (picture should be enough so they can understand your point).
  


viivo said:


> Figured it would be better to ask here than start a new thread.
> 
> Paste of the question I posted elsewhere:
> 
> ...


 
 OPA2132P is quite low-cost, just purchase a new one. Or go for the original OPA2134, should be the same sound.


----------



## plainbriny

Got two Chinese "47" op amp kits recently.
  
 Both are using NE5532 (one comes with TI NE5532P and one comes with Signetics NE5532N).
 They are both low cost (less than USD$6) and the building process is fun.
 One is dual power (+ and - 9-15V, left), and the other is single power (3.7 - 30V, right).
  
 The dual power version (left) comes with very low end components, so I replaced all the capacitors.
 Both sound surprisingly good, considering their prices!
  

  
 Just ordered some ops, will try different ops in the next couple days.


----------



## santodx5

raoultrifan said:


> I meant the non-polarised rectangular grey caps nearby the DIP8 I/V opamps (you also need to double check this yourself by following PCB traces and comparing if these caps are connected between V+/V- pins and GND). The big blue caps should be output audio caps for lowering DC output (if any). Instead ES I'd vote for the KA, but feel free to read their datasheets and compare. Anyway before upgrading the big blue output caps feel free to short-circuit them for good with some short wires ("best cap is no cap") and see if something got improved (measure the DC output prior to connect the XLR plugs to an amp and if DC output is higher than 5mV maybe you should check if the connected amp has DC-servo or DC protection caps in input/output signal path!); if nothing got improved, then don't bother upgrading these caps.
> 
> For the opamp decoupling I'd vote for 10uF/35V tantalum caps + 1uF+ 0.1 MLCC, if possible for both I/V and LPF stages (at least for the I/V). If do you intend to use only MUSES then existing decoupling might suffice. Anyway, sometimes wrong caps might do more wrong than good, so please use a scope if you intend to change decoupling caps (https://www.baldengineer.com/a-1uf-decoupling-capacitor-is-too-much.html).
> 
> If you don't want to bother with scope and soldering parts, just get the MUSES01 for the I/V and try a couple of BURSON V5i in LPF; check for overheating and if everything seems fine then purchase the remaining opamps. BTW, what's the voltage on V+/V- for these opamps, please?




I think those rectangular caps are 1nf. Hmm should i change them into better component?amtrans amch or wima mk5. What do you think?


----------



## raoultrifan

santodx5 said:


> I think those rectangular caps are 1nf. Hmm should i change them into better component?amtrans amch or wima mk5. What do you think?


 
 Well, I was only 1.000 times wrong, no big deal I'd say. 
  
 On pins 4 and 8 there are 2 SMD caps, feel free to measure them with a multimeter and power off, though I'm not sure the value will be correct, because caps should be measured outside the circuit. I would say not to worry too much for the moment with the decoupling, unless your upgrade opamps will not oscillate. I'm sure MUSES01 & 8920 will be fine with existing decoupling when used in I/V stage; for LPF I think most of the above mentioned opamps should be OK.


----------



## viivo

Thanks for the responses. I have a followup question: would an opamp work at all if damaged or is it all or nothing? I got impatient waiting for the replacement to arrive so I soldered the two broken pins back on and reinstalled it. I ask the above because, while it does work, it sounds off in ways I can't articulate. All I can say is that a pair of 600ohm DT-990s sound better unamplified on my tablet than with this.


----------



## dukefx

If it's dead you won't hear a thing. If the sound is off it might be a soldering issue. I once had the left channel crackling and hissing. Turned out I didn't solder one of the pins properly.


----------



## palermo

Anyone, is there benefit to swap LPF from opa1642 to ada4610-2. The dac is ak4490eq.


----------



## Rroff

Can't see there being much in it - the ADA is designed with that kind of use in mind but the 1642 I believe has slightly better specs so any differences in terms of suitability to application probably balance out. Try it see if you notice any difference.


----------



## Nec3

Hey everyone, any suggestions for the HD600 pairing? Objective 02 amp with an Objective DAC here. I'm not interested in getting into tube rolling because from my experience I get introduced to bad tubes... opamps are more reliable.

 Right now I'm using NJM4556AD x2 with a Muses02. The HD600 with Muses02 sounds sparkly, has some good bass extension/texture/tightness, relaxed upper mids, sparkly treble, good soundstage and thick vocals, maybe a little too thick.

 The LME49720HA is detailed, sparkly, airy, upfront involving sweet mids, introduced mids too upfront and the HD600's 3-5khz started to shine out which became too much for me.
  
Is there an opamp that meets those two halfway? I can only assume the Muses01 would be a less thick Muses02.

 Edit: Also no, I'm not switching over to the HD650! That airy extension past 10khz is a must for me on the HD600.


----------



## raoultrifan

When used in voltage amplification stage they should all from above sound the same, also the original NJM2608, NE5532 etc. MUSES opamps are a bit more musical and soundstage seems wider a bit, but no matter what opamp you're rolling in VAS sound will be quite neutral (unless you're choosing a fast opamp that start oscillating, then you'll start to like the sound a lot).
  
 Feel free to try 2xMUSES02 in output buffer stage, but take care, because by doing this you'll limit output current capabilities from 150mA to 100mA and headphones like Hifiman or low sensitivity planars that requires lot of current to drive might destroy both of your opamps. Also, like Alex (adydula) said in Objective2 thread and on diyaudio forum, 2x1688 opamps might sound a bit better to your ears, just read those threads and see for yourself if worth the trouble or not.


----------



## Rroff

> Feel free to try 2xMUSES02 in output buffer stage, but take care, because by doing this you'll limit output current capabilities from 150mA to 100mA and headphones like Hifiman or low sensitivity planars that requires lot of current to drive might destroy both of your opamps. Also, like Alex (adydula) said in Objective2 thread and on diyaudio forum, 2x1688 opamps might sound a bit better to your ears, just read those threads and see for yourself if worth the trouble or not.


 
  
 While not relevant to Nec3 something else to keep in mind is that in situations like that is that not all op amps will play nice with the 1ohm output resistors and might require bumping that upto 4ohm or so. If I read the datasheet right MUSES02s would exceed their absolute max thermal dissipation when supplying current the ~75ma required for 150ma output at the voltages used in the O2 never mind their max voltage heh.
  
 This is all my _subjective_ impressions from building around a half dozen variants of the O2 but:
  
 HD600s are very low current demanding which opens up a lot of options for the O2 buffers - I'm not a fan of the NJM4556AD with the HD600s (though they work very well with high current demanding headphones) - I might be completely wrong as to what the problem is but their slew rate is marginal for audio and crucially stated as their typical not the more normal minimum rate - IMO the HD600s show them up for their inadequacy there - I'm a fan of the OPA1602 for buffers here as you get a very natural sound but they might not be as resolving for detail as some might like also a fan of the AD8066 here if you can get past the veiled upper mid-range as they seem great for bass, vocals and airy high frequencies. (EDIT: Looking through the thread seems more experienced people prefer the 1662 over the 1602 for better instrument separation/detail or the 1688 as above).
  
As an aside and I'm not sure what the logic is to it - I've had good results with omitting C10 (0.22uf) and putting 10uf audio grade (KZ or FC) aluminium electrolytics rail to rail directly on the op amps otherwise there seems to be some narrowing of the sound stage compared to when using my HD600s with high end commercial amps.


----------



## adydula

The 1688's work well for me....but there is also the AGDR O2 Booster Board creation (OPA827 + LME49600 looped). You can build one or buy one from AGDR I believe.
  
 The 1688 require some soldering and an adapter.
  
 I think if you go over to DIYAUDIO.COM there is more data on the 1688's, I think AGDR was concerned with oscillations with the 1688's depending on cable capictance etc...I tried to make my 1688 O2 oscillate by changing caps but it seemed solid. Sounds good!
  
 Alex


----------



## Rroff

For some reason I was concentrating mostly on the buffers above - probably because for me that has been one of the weaknesses with my HD600s.
  
 The 1688 even with low gain in the first stage shouldn't see the buffer as a high capacitive load right? so shouldn't be a problem in that respect though the lack of close 0.1uf bypass might be an issue in some circumstances.


----------



## raoultrifan

OPA 1688 might be used as output buffers and not voltage stage in Objective2.


----------



## weedophile

Hi guys, am looking to get a cheap portable amp to bring around with my Benjie S5 and chanced upon the Bluebird U3 Mini. What attracts me is its looks (much better than the Topping NX1A) and its available at almost the same price on AE.

So my question is since i can opamp roll with the amp (stock OPA264), can i say all 8 pins audio opamp will work with it? Or is there anything i have to take note of? (Sry i am a real noob on electronics and circuits)

Thanks!


----------



## vapman

santodx5 said:


> Hi all,
> 
> I have XTA 446 sound management module. It has 15 opamps (NE5532) inside. I never replace opamp before and have been reading forum like crazy to find the best opamp for me.
> 
> ...




What don't you like about it? The ne5532 sound is not everybody's cup of tea but for pure neutrality and honesty with good bass power few else come to mind. V5i in that large a quantity (15?) will be an extremely hefty investment. What do and don't you like about it? V5i sounds like ne5532 but with better soundstage imaging and treble extension but is otherwise very similar.


----------



## vapman

weedophile said:


> Hi guys, am looking to get a cheap portable amp to bring around with my Benjie S5 and chanced upon the Bluebird U3 Mini. What attracts me is its looks (much better than the Topping NX1A) and its available at almost the same price on AE.
> 
> So my question is since i can opamp roll with the amp (stock OPA264), can i say all 8 pins audio opamp will work with it? Or is there anything i have to take note of? (Sry i am a real noob on electronics and circuits)
> 
> Thanks!




There are single and dual channel opamps as well as dual to mono and mono to dual. It is probably a dual in there but as long as you get the same channel kind then you're all good


----------



## NCSUZoSo

My recent review (still in progress) on the Burson V5-OPA and V5i series. Includes DSD audio files and EL-8 open-back for playback to ensure quality. I will be posting a full video review after I receive a few replacement parts from Burson Audio.

 This is a very detailed review already, but it is still missing 1/4 of it or so.
  
 http://www.head-fi.org/products/burson-audio-supreme-sound-opamp-v5/reviews/17827

 or read it on my new website, always looking for new readers! https://zosoncsu.com/reviews/
  
 This is the video I am trying to expand on to create a video review. I would welcome any ideas on ways to use the written review + this type of analysis to make a full-length video review of an op-amp series.


----------



## weedophile

vapman said:


> There are single and dual channel opamps as well as dual to mono and mono to dual. It is probably a dual in there but as long as you get the same channel kind then you're all good




Thanks Mr Vap! Helpful as always


----------



## Emerpeje

Hey guys, I'm kinda new to this audio and electronics stuffs and I just bought a Walnut V2 player. Are there any suggestion on what kind of opamp that I should take to "upgrade"(not uograde, just change the soundsig a little bit) my Walnut V2?

 Thanks!


----------



## weedophile

emerpeje said:


> Hey guys, I'm kinda new to this audio and electronics stuffs and I just bought a Walnut V2 player. Are there any suggestion on what kind of opamp that I should take to "upgrade"(not uograde, just change the soundsig a little bit) my Walnut V2?
> 
> 
> Thanks!




U might want to check out the Walnut thread

http://www.head-fi.org/t/828315/walnut-hi-fi-v2-wav-mp3-player-by-wt-screenless-budget-killer-combo-dap-amp/1125#post_13157889

Cant remb when but they were talking abt it not too long ago


----------



## Emerpeje

weedophile said:


> U might want to check out the Walnut thread
> 
> http://www.head-fi.org/t/828315/walnut-hi-fi-v2-wav-mp3-player-by-wt-screenless-budget-killer-combo-dap-amp/1125#post_13157889
> 
> Cant remb when but they were talking abt it not too long ago


 
 Wow thanks! Didn't realize about that thread, just go straight to this opamp section. Really appreciate it


----------



## weedophile

emerpeje said:


> Wow thanks! Didn't realize about that thread, just go straight to this opamp section. Really appreciate it


 

 No worries bruh, welcome to the Walnut club!


----------



## Lohb

weedophile said:


> Hi guys, am looking to get a cheap portable amp to bring around with my Benjie S5 and chanced upon the Bluebird U3 Mini. What attracts me is its looks (much better than the Topping NX1A) and its available at almost the same price on AE.
> 
> So my question is since i can opamp roll with the amp (stock OPA264), can i say all 8 pins audio opamp will work with it? Or is there anything i have to take note of? (Sry i am a real noob on electronics and circuits)
> 
> Thanks!


 

 I heard the Bluebird U3 mini was a bit iffy for QC. I'm taking a chance on the new Bluebird U6-PLUS ( the new solid alu. billet machined one) for my IEMs as the specific OPA2604 it ships with goes great with my IEMs on my PB2 balanced amp ( 4x 604s).


----------



## weedophile

lohb said:


> I heard the Bluebird U3 mini was a bit iffy for QC. I'm taking a chance on the new Bluebird U6-PLUS ( the new solid alu. billet machined one) for my IEMs as the specific OPA2604 it ships with goes great with my IEMs on my PB2 balanced amp ( 4x 604s).


 

 Ahh icic. Not much can be looked up on the Bluebird. Shall look around more before i pull the trigger


----------



## Tuluum

So, I have a bit of an interesting request for help..
  
 I have recently finished a pair of (Open) Alpha Prime headphones and have been powering them with a simple CMOY built around a 5218A opamp  (just the best sounding opamp I had laying around).
  
 My initial plan was to just start rolling opamps, as well as design a more advanced amp myself.  However, I have started to feel that my health is simply going to get in the way of this and time is an issue.  This project has been mainly myself, but I have been working on it with my Dad, who has been given a relatively short time to.. live. It has been a truly wonderful way to spend time together, and Id like to see it to fruition.
  
 Between our health issues, I have instead been trying to find a solution that will be as cheap as possible and as good as possible right off the bat. I tend to prefer the warmer sound of tubes, but I think resources might be too short to really make that happen. So, I have been trying to do research on existing amp schematics as well as trying to find the opamps that will fit best.  This has turned into a bit of an exercise in frustration as there are _so _many resources.  Normally, Id love that, but in this situation it is simply not ideal. Frankly, I seem to be a bit too scattered overall to drill through it.
  
 Down to business, could someone help direct me towards not just a great sounding design, but the opamps that would work best for the input and output stages?  Anything over ~$10 a piece is really, really stretching it so ICs like the MUSES02, Burson, etc. are simply out.  Of course I am looking for a good, warm sound, but this project has more meaning than that too.
  
 I have most general parts on hand, but specifics will need to be purchased.  That should help keep costs down, but it certainly doesn't open it up enough to get the more expensive pieces out there. Despite all this, I think we can come up with something that is pretty darn good, but I find myself in need of a bit of help to find the right direction.


----------



## vapman

tuluum said:


> So, I have a bit of an interesting request for help..
> 
> I have recently finished a pair of (Open) Alpha Prime headphones and have been powering them with a simple CMOY built around a 5218A opamp  (just the best sounding opamp I had laying around).
> 
> ...


 
 I would recommend a non-TI branded NE5532. Really any of other brands but TI have better QC and therefore better sound quality. A nice 5532 is not far off from the tone of a nice 6N30p tube imo. Good luck on your build. I don't think the 5532 will disappoint in the slightest.


----------



## pelopidas

LME49990 is very good. A must try.


----------



## raoultrifan

tuluum said:


> My initial plan was to just start rolling opamps, as well as design a more advanced amp myself.
> [...]
> 
> Between our health issues, I have instead been trying to find a solution that will be as cheap as possible and as good as possible right off the bat. I tend to prefer the warmer sound of tubes, but I think resources might be too short to really make that happen. So, I have been trying to do research on existing amp schematics as well as trying to find the opamps that will fit best.  This has turned into a bit of an exercise in frustration as there are _so _many resources.  Normally, Id love that, but in this situation it is simply not ideal. Frankly, I seem to be a bit too scattered overall to drill through it.


 
  
 MUSES8820, but also MUSES8920 if you want to spend money to get both.


----------



## Tuluum

​The NE5532 is actually one of my current picks, but Im glad to hear that it at least mimics a tube-type sound.  I have to say I really like the price on it, and alongside the MUSES, its really in the lead for final choice.
  
 Some of the other "leaders" are the cheaper MUSES (I like the name... and yes that's silly), AD8397, LME49720, OPA1611, and OPA1688.  I looked into the LME49990, but cant seem to find it readily in stock. I haven't actually heard any of them though, and I don't like that (everyone here probably understands that one!)
  
 I missed saying it, but I'm looking to spend $25-$30 total on all stages, so I'm not INCREDIBLY limited.  It just rules out some.  Ive honestly had some trouble thinking straight recently, so please bear with me .  On my end, I'm hoping my experience and equipment can compensate for current issues when it comes to actual construction.  Auto-pilot and muscle memory has saved me quite a bit as of late, but sometimes it has _not. _
  
 In the end, I kind of feel I would be pretty happy with any of these picks, but I'm also struggling to find a design to either clone or use as a foundation. I already know I'm not up to doing anything from scratch, but circuits like the CMOY just aren't quite up to snuff.  I think some more quality can be achieved, but I also want something a bit more involved so we can work through it. I'm currently just leaning towards adapting Walt Jung design, but I'm also hopeful for some more recent alternatives.


----------



## Tuluum

@raoultrifan

 Have you had any experience with the 8832?
  
 I have definitely been looking at the MUSES intently, but at basically double the price of everything else in the running, that gives me pause.  My need to tinker is still in play, and if I take the MUSES out of my cart, I can get the AD8397, LME49720, NE5532, OPA1611, and OPA1688 for <$20. That might still require another shopping "trip" a week or two down the line, but I think that's doable.
  
 I still have to get pads for my modded Fostex, though I'm strongly debating keeping the stock ones (as much as I dislike them) in order to open up a bit more opportunity in this realm of things.
  
 ETA:  Looks like quoting is the way to go, rather than clicking reply!


----------



## Rroff

If you like tubes then stuff like the OPA2228 (note its only really stable above gains of 5, not unity stable and fussy about compensation caps, etc.) and OPA1602 are worth a consideration. The 2228 has a rich tube-a-like mid-range but the bass and treble are much more solid state sounding while the 1602 is mellow and neutral slightly rolled off towards the top and bottom.

Personally I wouldn't say the OPA1611 or 1612 and OPA1688 are really for someone who like tubes as in my experience they have a slightly bright and energetic sound.

Topology wise I'd either look at O2 variants or something like the PPA - both are possible to simplify significantly with great sound if you want i.e. miss out the power management circuit on the O2 if its entirely desktop wired in if you want to keep it simpler.

While the O2 type setup is pretty hard to beat without going super high end my current favourite is actually a 4 channel (active ground) setup that is similar to the PPA but omits the outer loop and buffer using AD8066 op amps (as its setup for "balanced" output it uses separate isolated power supplies for each left and right channel).


----------



## Lohb

tuluum said:


> So, I have a bit of an interesting request for help..
> 
> I have recently finished a pair of (Open) Alpha Prime headphones and have been powering them with a simple CMOY built around a 5218A opamp  (just the best sounding opamp I had laying around).
> 
> ...


 
 LME49990 + BUF634P


----------



## raoultrifan

tuluum said:


> @raoultrifan
> 
> Have you had any experience with the 8832?


 
  
 No...and I'm not interested to test the 8832 opamp, sorry.
 8820 is a wire with gain in voltage amp. stage and is not so expensive either.


----------



## vapman

You could consider a Burson V5i but it is hit or miss on synergy.


----------



## ph0n6

I got a pair of 8820 myself, sounds very good for the price, I prefer it to the OPA2107.
 Anyway, have anyone got their hands on the Muses03? It seems that mouser have them in stock but only in 2000 units reel?


----------



## FritzS

Take a view to MUSES8920 too
 http://www.njr.com/MUSES/series/MUSES8920.html
 http://www.njr.com/semicon/PDF/MUSES8920_E.pdf


----------



## Rroff

ph0n6 said:


> I got a pair of 8820 myself, sounds very good for the price, I prefer it to the OPA2107.
> 
> Anyway, have anyone got their hands on the Muses03? It seems that mouser have them in stock but only in 2000 units reel?



 


Showing no stock and 13 week lead time for me (UK version of mouser) - as its a new line possible the minimum order quantity will change when/if they actually have them properly in stock instead of ordered in on demand.

Personally don't really rate them mostly because of the price versus other offerings that are either really close or I can't tell the difference and much cheaper.


----------



## Lohb

fritzs said:


> Take a view to MUSES8920 too
> http://www.njr.com/MUSES/series/MUSES8920.html
> http://www.njr.com/semicon/PDF/MUSES8920_E.pdf


 

 have you compared it vs the newer Muse01/02 ?
 Interesting, and a great price.


----------



## snellemin

Bought me something interesting.  Sounds pretty good.  A bit smaller than the Burson V4.  It's uses dual opamps, and one being the buffer to the other.


----------



## raoultrifan

Looks originals, pretty hard to find.


----------



## Tuluum

First off, I wanted to thank everyone for their feedback.. It is much appreciated!
  
 Quote:


rroff said:


> If you like tubes then stuff like the OPA2228 (note its only really stable above gains of 5, not unity stable and fussy about compensation caps, etc.) and OPA1602 are worth a consideration. The 2228 has a rich tube-a-like mid-range but the bass and treble are much more solid state sounding while the 1602 is mellow and neutral slightly rolled off towards the top and bottom.
> 
> Personally I wouldn't say the OPA1611 or 1612 and OPA1688 are really for someone who like tubes as in my experience they have a slightly bright and energetic sound.
> 
> ...


 
  
 Thank you specifically for this.  I had been eyeing the PPA for a bit, but I'm hesitant to do such an involved build without actually hearing one first.  Ive gotten over that, since I think its just how its going to have to happen right now 
  
 I'm still debating between the o2 and the PPA, but I think Ill end up going for the PPA.  I need to get some parts, but have a lot on hand and I like that it has a discrete stage and can be class A biased.  I even found a thread about turning it fully discrete, but that will be down the road (if I ever get there).  I'm going with the suggested AD8610, but will also be purchasing pairs of NE5532 (ON semi), OPA2228, and OPA1602. They may not make their way into the PPA, but I think they will be fun to play around with in small cmoy/3-channel cmoy/a47 projects.
  
 However, having to etch my own PCB isn't too exciting to me at this point in my life, so that's a big tip of the hat to the o2 (PCB is readily available).  When all is said and done, Ill probably go with the PPA, test it out on a breadboard and never move it into an actual enclosure anyway though..  I like to tell myself I don't do things like that, but I do. 
  
 Do you have any more info/links on that 4-Channel PPA variant? ETA: Now I'm also looking into the CK2III...


----------



## Rroff

Closest (and its missing quite a bit of what makes the PPA the PPA) is this http://www.head-fi.org/t/553236/pseudo-balanced-amplifier-pba - I came up with my own reworking of the PPA for balanced use which I don't really have committed anywhere as a cohesive thing at this point - I'm still experimenting with what works best.

IMO the O2 type topology is very hard to beat with a relatively simple circuit you have to go very high end even to match it - that said IMO nwavguy kind of sabotaged it in an effort to prove a point - despite it being somewhat subjective some simple modifications at a little more expense largely using "boutique", etc. components does make it far more pleasurable to listen to and tolerant to a wider range of operating circumstances - the original design/component selection performs very well within controlled circumstances but in the wider world you can easily encounter some issues.


----------



## adydula

Someone has looked at the O2 on an AP analyzer....you might find this interesting..

https://www.neurochrome.com/o2-headphone-amp/

Alex


----------



## Rroff

Oh nice not seen that one before.

I've always been sceptical about the NJM4556 on the output - seems to work fine with high current demanding headphones but with my HD600s at times can notice loss of articulation and higher pitched vocals can sound almost "genderless" which I've kind of ascribed to the slew rates though that article tends to imply that the slew rates are just about ok.

You also have to be pretty careful with the power level of the source input versus the amps supply vrms, gain and volume control position as otherwise as per the article its really easy to drive the amp into distortion - within controlled circumstances or with some slight tweaking it works much better.

I made a low voltage version with OPA1612 gain, LMH6643 output op amps, changed C10 (0.22uf film cap) for a 10uf audio grade aluminium electrolytic (in this case elna silmic ii) and uprated the other film caps to polypropylene where appropriate and changed the regulators to a LM317/337TG pair and its far more pleasurable to listen to with noticeably more spacious sound - LMH6643 do kind of degrade the noise performance a bit but keep the current capability intact should I want it.


----------



## NCSUZoSo

Finally took the plunge and upgraded the first four surface mount opamps on the Creative ZXR (1st stage). I made a mess out of it right out the gate. I had pads lifting off the PCB with the op-amp itself, not realizing I needed 550-600F for the lead free solder used on the board. This lead to me having to repair about 8 pads in total (finding their nearest trace connection point and bridging to the op-amp leg/pad area). In the end, I think it came out decent. When a few people first saw the pic with the opamps removed were like d*mn, he killed his modded ZXR, lol.
  
 The stock opamps were  JRC 2114s and I upgraded them to BB 2604AUs. Haven't had enough time with the card using surround sound to give an opinion on a change.


  
 Some of my modding rig/engineering tools.


  
  
 If I notice enough improvement in the sound I did make a video of the removal and the install, but I think the best option for anyone wanting to upgrade the rear speakers and center/sub opamps is to invest in DIP8 to SOIC8 adapters

 $5 + $6 S/H is 1/2 the cost of similar adapters elsewhere and if you buy 4-6 of them, the shipping isn't so bad.


  
  
 http://www.ebay.com/itm/361490134147

 Just thought I would throw this in here in case someone ever tries to do this and here is the full ZXR thread post: http://www.head-fi.org/t/623079/creative-sound-blaster-new-series-z-zx-zxr/3360#post_13237344


----------



## Spider fan

renfield1217 said:


> Hi gr8soundz,
> 
> The STX, ST, and STXII all use the same opamp setup. They use 3-duals so with Sparkos you would need 3-SS3602's (2 for the I/V sockets and 1 for the buffer/LPF). If you are using the headphone out only the I/V opamps are used, if you are using the line out then all 3 sockets/opamps come into play.
> 
> ...


 

 Thanks your post got me researching the Sparkos SS3602 and after reading the reviews online I had to order one to replace my 8820.  Andrew the owner was super helpful answering my multiple questions too.


----------



## zilch0md

Let's hear it for Sparkos Labs!  
  
 I so love the way the SS3602 sound in the input voltage gain stage of my portable iBasso PB2, with dummy buffers (no current gain, but less noise), that this has become my absolute favorite amp. 
  
 I find my SS3602-equipped iBasso PB2 portable amp to be:
  

Better than my Meier-Audio Corda Stepdance (the SS3602 has a more analog, less "crystaline" sound, yet every bit as neutral and resolving and with the same black noise floor)
Better than my CEntrance DACmini CX amp section (the SS3602 isn't as "grainy" in the treble)
Better than my Oppo HA-1 amp section (the SS3602 isn't as bright, nor is at as harsh with HD800, which just can't be used with the HA-1)
Better than my Metrum Acoustics Aurix (the SS3602 has much better dynamics, but just as neutral and with just as low a noise floor)
Better than my iBasso PB2 with any other op-amps, including the Burson V5 Duals, with which I was very content until I heard the SS3602 (which are more resolving, with a lower noise floor, not to mention much better quality control and a smaller form factor).
  
 The SS3602-equipped iBasso PB2 sounds so much better than my other amps, I've been using it, with multiple headphones, all with balanced cables (PM-1, HD800, Beyer DT880 600-Ohm)  to beta test the new Oppo Sonica DAC that was just released. _Put a good DAC in front of an SS3602-equipped amp and you can really appreciate what Sparkos Labs has accomplished._
  
 I think it's primarily due to the low noise of the SS3602 (see the comparison chart below), combined with its power, which allows me to operate at lower gain settings for any given load, combined with the fact that my PB2 is battery powered - having no need for AC power conditioning. The resulting pitch black noise floor allows lots of micro-details to be heard, even at low listening levels. Gone is the tendency to play too loudly, just to enjoy everything the recording has to offer.  
  
 It looks silly, using a portable amp with a big desktop DAC, yet my ears say it's anything *but* silly.  
  
  

  
  
 SS3601 (single) comparison chart:

 Mike


----------



## dukefx

I also love the SS3602. It has clean bass and an overall very natural sound.


----------



## northendjazz

I've been running the single sparko's SS3601 in a Neco Soundlab V4 Dual Loving every minute but sparko's state "+/- 6V to +/- 18V supply voltage range" while the V4 is a 20V. I'm not going to roll any more opamp's in the V4 so do I ask the amps maker to reduce the supply voltage to 18V to be within the sparko's range?


----------



## zilch0md

northendjazz said:


> I've been running the single sparko's SS3601 in a Neco Soundlab V4 Dual Loving every minute but sparko's state "+/- 6V to +/- 18V supply voltage range" while the V4 is a 20V. I'm not going to roll any more opamp's in the V4 so do I ask the amps maker to reduce the supply voltage to 18V to be within the sparko's range?


 
  
 Cool, another portable amp that can use the SS3601.  Joy!
  
 Try contacting Sparkos first, to see if 20V is actually too high.  (He probably _will _tell you it's too high, but maybe his specs have a safety margin.)


----------



## vapman

Are there any dual versions of those ss360x opamps? Would be interested to try one in my walnut


----------



## dukefx

SS3601: single
 SS3602: dual
  
 Otherwise they are identical.


----------



## abartels

Hi Guys,
  
 I promised a review of the Burson V5 a long time ago, and finally here it is!
  


  

  
 My dac (I call it The MonsterDAC - thanks to @motberg ) is based on AK4495SEQ from diyinhk.
 To be honest, the name is not correct because this isn't a DAC but a networkplayer, based on Raspberry Pi3 with PicorePlayer.....
  
 My starting point was to get the best out of the diyinhk AK4495SEQ implementation.
 Of course, all starts with choosing an enclosure. I found this one very appealing, a 430x350x60mm 6kg full aluminium housing.
 Since I wanted the DAC and FIFO II (including DUAL XO II board) as much as possible isolated from transformer vibrations,
 I did choose for a wooden sub-chassis for all R-Cores, PSU's and EMI/RFI filters. All R-Cores are fully mounted in rubber onto the
 wooden subchassis to prevent transferring the (minimal) vibrations the R-cores produce. Also DAC and FIFO II kit are fully mounted in rubber,
 thus completely isolated from transformer and other vibrations.
  
 I did choose R-Core transformers with electrostatic shield and copper outer shield for best performance.
  
 Further, wooden subchassis, aluminium parts and RPI are fully covered and shielded with copper, which is connected to ground.
  
 The DAC PCB is heavily modified, for example with much bigger cap values, especially for VREF, has ALL powerlines seperately fed etc.
 All powerlines have a dedicated 0.8uV ultra low noise PSU (LT3042) with EMI/RFI filter on board, all PSU's have a dedicated R-Core,
 and all R-cores have a dedicated EMI/RFI filter.
  
 All EMI/RFI filters for DAC, FIFO II kit and RPI are connected to another, bigger EMI/RFI filter which keeps all digitall stuff seperated from analog stage.
 Analog stage has it's own EMI/RFI filter (and, of course R-Core and 0.8uV PSU's) which is connected to mains *before* the bigger EMI/RFI filter for all digital stuff.
 This way it keeps PSRR at the highest possible value.
  
 DAC is fed thru I2S from Ian's FIFO II kit.
  
  
 At first I used LME49720HA (MIL-SPEC metal can which DOES sound different from plastic version) and compared it with Burson Audio SS V5i
 http://www.head-fi.org/t/432749/the-opamp-thread/5325#post_12799851
  
 Burson Audio SS V5i clearly was the winner! Very good sounding opamp which comes close to discrete outputstage in my opinion, so I used V5i for a while.
  
 I couldn't resist to compare Burson Audio SS V5i with a low cost Chinese discrete FET output stage:
 http://www.head-fi.org/t/432749/the-opamp-thread/5325#post_12802191
  
 At first, after burn-in, it sounded better, soundstage was very wide and deep, but after a while all went worse, bass was overstressed which killed the overall tonality.
 To me it sounded kind of dull. Finally I went back to V5i and again was very pleased with it's performance 
	

	
	
		
		

		
			




  
 I kept it this way for a long time but finally replaced Burson Audio SS V5i with V5 for reviewing, as promised 
	

	
	
		
		

		
		
	


	



  
 After burn-in time, about 150 hours, it immediately sounded a lot better than the V5i. They, V5i and V5, both have same sound characteristics.
 The presentation is very musical, mellow, lots of detail and room information, no hint of harshness.
  
 V5 presents it in a way I never heard before, (that is, except with my own build discrete Class-A - build with Ferranti Mosfets - output stages).
 Vocals and instruments are very natural sounding, lifelike, many recordings gave me gooseflesh. The overall presentation is just amazing, the field of depth,
 the ability to present accurate layers, the wideness of the soundstage (it's much bigger than my listening room, in width, depth *and* height),
 blackness around voices and instruments, it's just breathtaking!
  
 Also, all funny 3D and Phase gimmicks, which are present in many recordings, such as sounds BEHIND or LEFT or RIGHT from you, now really are stunning.
 For example, I have a recording from some of the Telarc sample cd's (sorry, not sure which one it is) in which there is an arrow shot from behind the speakers
 into the left side of the room, this now REALLY sounds as if it hits just next to me, on the left side, while before it was somewhere in the middle of the left wall.....
  
 In my design Burson Audio SS V5 doesn't get too hot, to me it feels a few degrees above body temperature, maybe about 45 degree Celcius.
  
 Sadly I made a mistake and asked Burson for 2x Dual version while I meant to use 2x Single for which I wanted to use seperate PSU lines.
 Good thing is, this will keep some room for improvement and something to wish for 
	

	
	
		
		

		
		
	


	



  
  
*Verdict*:
  
 If you have a high quality DAC, networkplayer, preamp, source device, bufferstage or whatever kind of opamp based outputstage, try the Burson V5 discrete opamps,
 you will be pleasently be surprised on how these devices (can) perform (depending on your design)! To me they are a keeper 
	

	
	
		
		

		
		
	


	



  
 I never tried the bigger V4 version, maybe that is something to keep in mind too 
	

	
	
		
		

		
		
	


	



  
  
*Note:*
  
 If you plan to buy and use V5, you probably better contact Burson first in relation to unity gain and power consumption needed within the design of your device.
  
  
*Last but definitely NOT least:*
  
  
 Many, many thanks to @SS-Audio Charles from Burson who provided the V5 samples and made it possible for me to review the grand SS V5! 
	

	
	
		
		

		
		
	


	



  
  
  
 Regards,
 Alex


----------



## slex

Wow how many red V5 are there? Yes The Red V5 made my Oldies MHDT Paradisea 3 TD1545A NOS DAC into a beast but yours a monster


----------



## dukefx

I only see 1 V5 (top right on the 1st and 2nd pic, on the right on the 3rd). You are probably mistaking the caps for V5s.


----------



## slex

dukefx said:


> I only see 1 V5 (top right on the 1st and 2nd pic, on the right on the 3rd). You are probably mistaken the caps for V5s.



Haha i guess so


----------



## NCSUZoSo

So I just received my newest review samples from Burson Audio!!!

 They sent me replacement V5-OPA and V5i op amps, allowing me to run all V5-OPA's in the ZXR Front L/R op amp locations finally!
  
 They also sent me their new Cable+ (RCA-to-RCA) that actually utilizes the V5i op-amp to turn every RCA signal into line level. So far my impressions are highly impressed when compared with Canare L-4E6S (Star Quad) & Mogami 2534 (Quad) (all w/ Neutrik Rean connections), which by most, are considered the upper tier of premium cables with respect to the cables actually inside the cable and not the name on the jacket. You definitely pay for Mogami and Canare names, but nothing like the dumb "Monster Cables" you used to always see at Best Buy.

 Since the Cable+ uses a V5i it applies to this thread, kind of, lol. I thought you all would like to check it out if you haven't already.
  




 I have mostly been using the Cable+ with my Aune T1 setup listed below and my Audeze EL-8s due to the ease of which I can swap and use one ear with one type (etc.).

 I will be doing a full review of the Cable+ technology and more on the V5-series besides the review listed below my signature. This time however I have an entire lab full of tools including a lab grade 30V/5A DC PSU, Weller WESD51, SMD Hot Air Re-worker etc. The main gadget I will be using this go round on reviews will be the Digilent Analog Discovery2 and the accessories I will be using with it like TI's Analog System Lab Kit PRO rig that allows easy testing of any op-amp in a variety of ways. I will be able to give SNR, floor noise, THD, etc. readings from the Analog Discovery2 (20Mhz 2ch. scope + waveform gen + multi-meter + GPIO digital header for expansion boards).

 I am excited about what this round of reviews is going to bring, but it's going to take me a good while to do it due to the time constraints of being a Jr in Electrical Engineering.


 (Note: I am an independent reviewer and receive no financial compensation from Burson or any other company)


----------



## snellemin

abartels said:


> Also, all funny 3D and Phase gimmicks, which are present in many recordings, such as sounds BEHIND or LEFT or RIGHT from you, now really are stunning.
> For example, I have a recording from some of the Telarc sample cd's (sorry, not sure which one it is) in which there is an arrow shot from behind the speakers
> into the left side of the room, this now REALLY sounds as if it hits just next to me, on the left side, while before it was somewhere in the middle of the left wall.....
> 
> ...


 
 I have the Telerc CD and it's called "The Great Fantasy Album" from the mid 90's.  The arrows track is from track 5 "Splitting hairs".
  
 The V4 sound great in amplifiers.


----------



## abartels

slex said:


> Wow how many red V5 are there? Yes The Red V5 made my Oldies MHDT Paradisea 3 TD1545A NOS DAC into a beast but yours a monster


 
  
 Yes, my beast is a monster, hahahaha, but it only does have ONE V5d, all the other red things you see are WIMA caps


----------



## abartels

snellemin said:


> abartels said:
> 
> 
> > Also, all funny 3D and Phase gimmicks, which are present in many recordings, such as sounds BEHIND or LEFT or RIGHT from you, now really are stunning.
> ...


 
  
 Thanks for your kind response 
	

	
	
		
		

		
		
	


	




 Yeah, the mid nineties, good times then 
	

	
	
		
		

		
		
	


	




 I had one of the first cd players in that time, sounding horrible, hahahaha


----------



## Lohb

Anyone know what the number and sometimes number/letter code bottom right on MUSES chips signifies...batch number/grade of chip etc ?
 http://www.njr.com/MUSES/series/MUSES02.html
  

  
 It seems there are many different codes on the MUSES 02 chip seller photos depending on the source.
 Giving China sources a pass, just too cheap to be true.


----------



## gr8soundz

lohb said:


> It seems there are many different codes on the MUSES 02 chip seller photos depending on the source.
> Giving China sources a pass, just too cheap to be true.


 
  
 I noticed that too and also passed on quite a few cheaper listings.
  
 EDIT: No idea what the codes mean and figure its better to get them from a confirmed (by many in this thread at least) genuine source.
  
 Looks like Mouser has them back in stock (they were out last time I bothered to check). Not a huge price difference and I only need one since neither the V5i nor Sparkos fit inside my portable amp.


----------



## morfic

With Digikey and Mouser having high minimum quantity requirements on Muses02 (if they even show stock), what's a good source for them?


----------



## ph0n6

Tmall do have the muses02 listed (even muses03, but no one has bought it yet though.) If I'm not wrong only registered "store" (or in this case company?) with certification can sell stuff on Tmall (unlike taobao which is essentially Chinese ebay). Their listing is cheaper than the asked 50 bucks from mouser (at least in my case where on may cost me about 26-27$ for one. Though currently I'm using the sparkos one so I have little incentive to try other non discrete solutions, maybe I will asked around in my community to see if they have a muses02 that I can try.


----------



## gr8soundz

morfic said:


> With Digikey and Mouser having high minimum quantity requirements on Muses02 (if they even show stock), what's a good source for them?


 
  
 Just tried both sites and I'm seeing 1 as the minimum on Mouser.


----------



## ScottFW

snellemin said:


> Bought me something interesting.  Sounds pretty good.  A bit smaller than the Burson V4.  It's uses dual opamps, and one being the buffer to the other.


 
  
 I recently received one (the piece on the right) from the same seller in Taiwan.
 I've only tried it in one device so far, an Audioengine D1. That was originally equipped with a single surface mounted 5532 between the DAC chip and headphones, but I have socketed it and tried a few other opamps in there. The D1 uses a sensible implementation for the 5532 with a gain of 4, 10 uF tants decoupling the rails right near the chip, a small value cap in the feedback loop (on the order of some pF; don't remember), and about 10 ohms between each output and the headphone jack to keep things nice and stable.
 Popping in the dual/buffer adapter shown above with a pair of 5532 as shipped, there is obvious background hiss at all volumes, some distortion at low volume and it gets worse as it's cranked up. Swapping in a newer/faster opamp in either position makes things even worse.
 The suboptimal performance could be due to the second opamp being configured as an open loop buffer. I knew this from the schematic before I bought it, and thought twice because of that, but nevertheless succumbed to curiosity because it was cheap. It would probably work better if the buffer opamp was inside the feedback loop of the first. I might be able to hack up the adapter to do that, but I also might not care enough to bother. Meh.
 I did not measure voltage at the chips while I tested, and perhaps I should. A stock D1 runs a single 5532 right at +/-5V give or take a couple hundredths of a volt in either direction (the lower limit of its spec) and given that it's a puny little DAC/amp I suppose the extra 10 mA drawn by a second chip could be taxing the power supply. Then again, I've tested other opamps in the D1 that draw about the same current as two 5532s and never gotten hiss & distortion like this.


----------



## morfic

gr8soundz said:


> Just tried both sites and I'm seeing 1 as the minimum on Mouser.




Thanks! Guess that means they got stock, minimum was 100 with typical vendor lead time of 12 weeks.

Now the age old question, as someone who enjoys LME49720 in pretty much everything he can get them into, are the Muses02 really 10x as good?


----------



## abartels

Hi guys,
  
 Last Saturday I revived my low-cost Chinese AK4495SEQ I2S Dac.
 This is one of the most affordable ($28) and sublime sounding Dac's (BANG for buck) I ever owned.
  
 This is the original:
  

  
  
  
 https://world.taobao.com/item/44350730621.htm?spm=a312a.7700714.0.0.XyranW#detail
  
 I did modify this one with bigger and better caps, especially those for VREF are very important.
 Since I tried it last time with an RPI and Ian's FIFO II kit, including a Burson SS Audio V5i-D,  I wondered how it would sound connected to an RPI with Allo.com Kali reclocker and a Burson SS Audio V5-D discrete opamp.
  

  

  

  
  
 This combo really sings 
	

	
	
		
		

		
			





 Since Kali reclocker is new and has to burn-in for a week, I can't comment on how it will sound when completely burned-in,
 but for now I have to say that this is a VERY musical sounding combination. The sound character is exactly the same as his big brother, the "MonsterDAC",
 of course this is because of the use of the same dac-chip, and the use of the outstanding Burson SS Audio V5-D discrete opamp. Not sure what the influence
 of the Kali reclocker is, in comparison with the Ian's FIFO II kit in the MonsterDac, but for now it seems this little combo comes frightning close to the performance
 of the MonsterDAC, which is a HUGE result!
  
 Just for fun I tried to replace the V5 with the V5i and started listening.
  
 As good as the Hybrid V5i sounds, (I still love it as an opamp, it surely is one of the best sounding opamps availbale on this globe), the V5 takes EVERYTHING
 a step further. I have to say, it just SINGS 
	

	
	
		
		

		
		
	


	



  
 Very glad I revived this combo, and, for sure, it STAYS 
	

	
	
		
		

		
		
	


	



  
  
*Last words:*
  
 Again, many many thanks to Charles at @SS-Audio for providing me with two of those exquisite Burson Audio V5-D's for which I am VERY thankful!
 Without them this review wouldn't be possible!
  
  
 Keep up the good DIY work 
	

	
	
		
		

		
		
	


	



  
  
 Cheers 
	

	
	
		
		

		
		
	


	



  
 Alex


----------



## estranged

Any idea http://www.profusionplc.com sells legit muses01 or 02 or not?


----------



## Lohb

estranged said:


> Any idea http://www.profusionplc.com sells legit muses01 or 02 or not?


 

 I doubt a UK company with online presence/address is going to sell dicky OPAMPs...that could be the death-nail to their reputation.... expect that from China single operator/no address sellers and some ebay sellers....


----------



## raoultrifan

I purchased 8 x MUSES01, 2xMUSES02 and a lot of 8820 & 8920 from them plus many other NJR/LRC stuffs (search_posts). They are indeed JRC/NJR authorised partner and I really don't know a better & safer & cheaper place to purchases MUSES opamps from within Europe.


----------



## SpudHarris

That's a nice find... I live in the UK and generally I order from Farnell as they are legit. Nice to know there are options, limited as they are.


----------



## estranged

I have received muses01s from profusionplc.
  
 Anyone else think muses01 sounds better than burson v5s?
  
 Switching from stock STX II opamps to bursons was wonderful but compared to muses01, bursons seem to exaggerate the bass. muses01 has a more neutral, clean and more detailed sound. It is more fun listening. At least for me.


----------



## raoultrifan

I've "heard" people telling about V5s being on the bassy side, though for me V5s was fine in Voltage Amp. stage. Anyway, MUSES01 is very good in I/V stage and usually those MUSES are wire with gain + a bit of...warmness specific to tubes I'd say,


----------



## pichu

Does anyone know any Opamps that would work with the HT Omega Claro Halo? I was looking at the Burson v5s but quite honestly I need something cheaper. Obviously I still am looking for quality. Any point in the right direction would be very helpful!


----------



## gr8soundz

pichu said:


> Does anyone know any Opamps that would work with the HT Omega Claro Halo? I was looking at the Burson v5s but quite honestly I need something cheaper. Obviously I still am looking for quality. Any point in the right direction would be very helpful!


 
  
 The Burson V5i are about the least expensive, custom opamps available. About half the price of the V5 and much smaller (should be able to swap all 4 Halo opamps). I use them in my Asus Essence ST card and (afaik) don't see any reason why they won't work with the Halo.


----------



## pichu

Do you notice a justifiable difference in sound quality? Also does it increase the volume of the amp? Im a noob at this stuff.


----------



## Emerpeje

Hey guys. I want to share my experiences with my Walnut V2 and opamps. I just tried OP27, OP97, LF412 (both linear and normal), and the carried opamp(don't remember the serial lol). 

Okay, first the OP27. Nice opamp to boost the mid and low sections. A little bit warmer than the default opamp. Improved both soundstage and detail(not much, but better). 
OP97, it's good. There are some improvements on the high, but not making them brighter. The high become more natural than the usual. And it improves the soundstage and separation(not much, but better than the default opamp), but not the detail. 
Then the LF412s. I tried the linear version and the normal version. The linear has brighter sound signature than thw normal version. But the detail, separation, and soundstaging is brilliant. I really like the normal version because it gives less coloration to the sound signature.


----------



## gr8soundz

pichu said:


> Do you notice a justifiable difference in sound quality? Also does it increase the volume of the amp? Im a noob at this stuff.


 
  
 The sound was noticeably improved with the V5i and I experienced about a 1dB increase in output. You can read more in my review here:
 http://www.head-fi.org/products/burson-audio-supreme-sound-opamp-v5i/reviews/17382


----------



## vapman

Running 2x v5i in a sound blaster xfi titanium hd. Sounds great... But you can't fit the card's cover back on!


----------



## Lohb

vapman said:


> Running 2x v5i in a sound blaster xfi titanium hd. Sounds great... But you can't fit the card's cover back on!


 

 V6i really just needs to be at standard opamp sizes with or without this cap that others don't seem to need.
 The footprint is already well established, so why completely ignore that fact ?


----------



## Lohb

Can anyone recommend a high current buffer that will be better than *BUF634P WP* ?
 It was stock with my amp, but looking at incremental buffer improvements now.


----------



## ph0n6

lohb said:


> Can anyone recommend a high current buffer that will be better than *BUF634P WP* ?
> It was stock with my amp, but looking at incremental buffer improvements now.


 
  
 A pair of LME49600 would do nicely if you don't mind soldering them into dip adapter.


----------



## FritzS

ph0n6 said:


> A pair of LME49600 would do nicely if you don't mind soldering them into dip adapter.


 
  
 Hearable differences between BUF634 and LME49600?


----------



## Lohb

ph0n6 said:


> A pair of LME49600 would do nicely if you don't mind soldering them into dip adapter.


 

 What difference would you say you were getting between the 2 ?
 Also I have the buffer with a tiny cap on it 'WP' model which is higher current flow, not the standard 634 unit.


----------



## zilch0md

*Here's a nice size comparison:*


----------



## ph58

Hi to everybpdy ! i'm totally newby about OP Amp rollings , i just want to know about  OP AMP , i have a Phone Amplifier that have double Mono construction that have 2 OPAMP . i want to replace with the Burson V5 ,   if i just replace one , do you thinks that it's gonna works !  Thanks in advance  .              PS : Sorry for my English , i'm French


----------



## abartels

ph58 said:


> Hi to everybpdy ! i'm totally newby about OP Amp rollings , i just want to know about  OP AMP , i have a Phone Amplifier that have double Mono construction that have 2 OPAMP . i want to replace with the Burson V5 ,   if i just replace one , do you thinks that it's gonna works !  Thanks in advance  .              PS : Sorry for my English , i'm French


 
  
 Hi,
  
 You need to be more specific, what kind of Phono amp is it? Brandname, typenr. Are those two stock opamps one for each channel (since it is dual mono design?), and what is typenr of stock opamps?


----------



## ph58

abartels said:


> Hi,
> 
> You need to be more specific, what kind of Phono amp is it? Brandname, typenr. Are those two stock opamps one for each channel (since it is dual mono design?), and what is typenr of stock opamps?


 

 Hi , it is the Citypulse EF3.01 : https://www.soundlabsgroup.com.au/p/Citypulse-EF301/Citypulse+EF-3.01+Headphone+Amplifier     it have 2 OPA627   Thanks


----------



## abartels

ph58 said:


> abartels said:
> 
> 
> > Hi,
> ...


 
  
 That seems already a very good designed and build Headphone amp! Those AD627's are used at input stage, one for each channel. Not sure if it's a good idea to change them.
 If you want my opinion, I think it is best to ask manufacturer if it is possible, and a good idea, to exchange those AD627 with Burson V5
 It could be that those AD627's are absolutely best at that stage and that it's not wise to replace them.
  
 This device has a discrete build output stage.


----------



## ph58

abartels said:


> That seems already a very good designed and build Headphone amp! Those AD627's are used at input stage, one for each channel. Not sure if it's a good idea to change them.
> If you want my opinion, I think it is best to ask manufacturer if it is possible, and a good idea, to exchange those AD627 with Burson V5
> It could be that those AD627's are absolutely best at that stage and that it's not wise to replace them.
> 
> This device has a discrete build output stage.


 

 Thanks for your reply , i kknow that the  2 OPA627 on the Citypulse(( not AD627 !) are very good , but i want to test and change for the Burson V5 (Burson supreme sound SS OPAMP V5) My question is can i replace just one Burson Mono V5 instead of 2 ? Does it work with ONE Mono Brson V5 ?   Thanks


----------



## vapman

ph58 said:


> Thanks for your reply , i kknow that the  2 OPA627 on the Citypulse(( not AD627 !) are very good , but i want to test and change for the Burson V5 (Burson supreme sound SS OPAMP V5) My question is can i replace just one Burson Mono V5 instead of 2 ? Does it work with ONE Mono Brson V5 ?   Thanks


 
 Don't ever replace one mono opamp and leave the other original.


----------



## ph58

vapman said:


> Don't ever replace one mono opamp and leave the other original.


 

 And if i remove one and place one Mono Burson V5 on the other emplacement ? Thanks


----------



## gr8soundz

ph58 said:


> And if i remove one and place one Mono Burson V5 on the other emplacement ? Thanks


 
  
 Why would you only want to replace one?
  
 Assuming the Bursons work (should confirm with the manufacturer that the specs are compatible), changing one opamp might, at best, likely make the left and right channels sound different from each other.
  
 For best results both opamps should be the same whether you replace them or keep the originals.


----------



## ph58

gr8soundz said:


> Why would you only want to replace one?
> 
> Assuming the Bursons work (should confirm with the manufacturer that the specs are compatible), changing one opamp might, at best, likely make the left and right channels sound different from each other.
> 
> For best results both opamps should be the same whether you replace them or keep the originals.


 

 OK thanks i ask this , because the Burson's V5 prices are expensive .    Regards


----------



## gr8soundz

ph58 said:


> OK thanks i ask this , because the Burson's V5 prices are expensive .    Regards


 
  
 I have the V5i which are about half the price (and size) but others who have tried both say the V5 sounds better.
  
 Also check with the manufacturer whether your amp uses single or dual (meaning type of supply rail not quantity) opamps. So you'll either need 2 dual opamps or 2 single opamps.
  
 If your amp, being dual mono, uses single supply opamps then those are also about half price each compared to the dual supply V5. But, for obvious reasons, single supply opamps can only be purchased in pairs (compared to being able to buy just 1 dual supply opamp).


----------



## ph58

gr8soundz said:


> I have the V5i which are about half the price (and size) but others who have tried both say the V5 sounds better.
> 
> Also check with the manufacturer whether your amp uses single or dual (meaning type of supply rail not quantity) opamps. So you'll either need 2 dual opamps or 2 single opamps.
> 
> If your amp, being dual mono, uses single supply opamps then those are also about half price each compared to the dual supply V5. But, for obvious reasons, single supply opamps can only be purchased in pairs (compared to being able to buy just 1 dual supply opamp).


 

 I have the answer to my question in a French site . Using one Mno OPAmp on a double Mono amplifier makes the sound comes up in just one channel (Left or Right) ! so i need to buy 2 Mono OPAMp !   Thanks


----------



## abartels

ph58 said:


> gr8soundz said:
> 
> 
> > I have the V5i which are about half the price (and size) but others who have tried both say the V5 sounds better.
> ...


 
  
 You wouldn't change only one front tire from your car from 185/55 to 205/55 either I suppose 
	

	
	
		
		

		
			




  
 OPA627 is unity-gain stable. And, as I said before, it is at INPUT stage. Ask Burson to look into this.


----------



## ph58

abartels said:


> You wouldn't change only one front tire from your car from 185/55 to 205/55 either I suppose
> 
> 
> 
> ...


 

 OK , i undrestand now . Thank you very much !   Regards


----------



## uncola

Just posted my review of the v5i.. http://www.head-fi.org/products/burson-audio-supreme-sound-opamp-v5i/reviews/18255
  
 tldr summary:  I swapped an opa2134 in my lehmann headphone amp for v5i, it changed from clinical neutrality to exciting and dynamic with a W shaped sound signature.. kind of like going from a sony mdr7506 to audeze lcd2, if that makes any sense.  complemented my hd800 for sure, added mid and bass impact and didn't make the treble any harsher.
  
 here's a cool pic showing the size difference of v5 and v5i


----------



## Rroff

That has always been my main criticism of the OPA213X that while they sound accurate enough it is like someone playing the same tune for the 1000th time some subtlety and passion is missing.


----------



## golov17

My love


----------



## vapman

^ wow a real MUSES!
 makes sense for a true vocal lover


----------



## Nurgayan

The current days show the market's desire to miniaturize components. Remember how Burson audio propelled its discrete devices in the opposite direction, now it also came to a contradiction to the original models.


----------



## raoultrifan

Well, actually we, consumers, asked Burson to create smaller SS opamps, because SS V4 and SS V5 couldn't be used in many Hi-Fi equipment (well, unless case remains open). So this is why they did the V5i.


----------



## Nurgayan

raoultrifan said:


> Well, actually we, consumers, asked Burson to create smaller SS opamps, because SS V4 and SS V5 couldn't be used in many Hi-Fi equipment (well, unless case remains open). So this is why they did the V5i.


 
Precisely, this is how the integral microcircuits were born. 
Simply, given the marketing policy of Burson at first, it looks rather strange. The logic built by them is broken.


----------



## raoultrifan

Well, inside the case there's an integrated opamp (not discrete) + some film resistors, so...some may say it's sort of an SS opamp too. 
  
 Anyway, SS V4 and SS V5 are really good stuff indeed, but V5i might do the trick in some upgrades.


----------



## gr8soundz

I finally posted about the Sparkos SS3602 swap I did late last year:
 http://www.head-fi.org/t/842335/discrete-op-amps-discussion-thread#post_13383409


----------



## Lohb

gr8soundz said:


> I finally posted about the Sparkos SS3602 swap I did late last year:
> http://www.head-fi.org/t/842335/discrete-op-amps-discussion-thread#post_13383409


 

 Yep, the increase in 'treble presence' is why I could not keep them....agree on expanded soundstage/also transparency improved.


----------



## Faber65

I have a question about the change of the opamp in a DAC. 
According to your experience, how much the opamp swap will affect the SQ?


----------



## abartels

faber65 said:


> I have a question about the change of the opamp in a DAC.
> According to your experience, how much the opamp swap will affect the SQ?


 
  
 It depends on VERY many factors.......
  
 To begin with, the weekest chain in the link limits the SQ.
 That said it means that others, with maybe better ears, or better equipment / total chain, CAN hear differences others couldn't.
  
 It's always very difficult to investigate what the weekest component in the chain is, but, to be honest, this is very important.
  
 For example, are you listening on headphones only, or are you listing on a full set in your listening room?
  
 Headphones can be VERY revealing, but listening to a set of very good speakers can reveal more than the best headphone set can, if room accoustics is optimal.
  
  
 I am not avoiding your question, but we need more information to help you.
  
  
 If equipment is optimal, and room accoustics are either, you definitely should hear a performance upgrade from an NE5532/34 for example to a LME49710/20 for example.
 But, that would depend on your system.
  
 If all optimal, I would say the difference could be HUGE, replacing simple and cheap/low cost opamps into high-end ones like the muses, or discrete options like Burson or Dexa,
 yes, it could be HUGE, but, maybe in your set it would be a 5% difference or so, maybe 60%, who can tell.......
  
 So, to answer to your question, switching opamp in a device CAN have a huge SQ increase, but all depends on the device which has to be upgraded, AND the chain it is in,
  
  
 Sorry for this disappointing answer, but that is just the way it is,
  
 Regards,
 Alex


----------



## Faber65

abartels said:


> faber65 said:
> 
> 
> > I have a question about the change of the opamp in a DAC.
> ...




Alex,

Your reply does a lot of sense to me and it is not disappointing at all.
I agree 100% with you, and I have experienced on that by swapping opamps on the Burson Lycan, as that was the purpose of that amplifier. 
My question was more specific on replacing the opamp on a DAC. 
Does it make the same difference that it does on the amplifiers?
I would like to have more opinions or measurements/data on that. 

Cheers
F.


----------



## gug42

Hello,
  
 Did you know a mono equivalent of the muses 8920 ?  (for a gustard H10 and a sb ZxR)
  
 By the way I ve seen that njr start to tallk about a muses03 ... but well can't find any.
  
 thx in advance !


----------



## abartels

faber65 said:


> abartels said:
> 
> 
> > faber65 said:
> ...


 
  
 Theoratically it does make the same difference as in an amp. But, as always, our ears tell the truth, and measurements aren't always conclusive.....


----------



## raoultrifan

faber65 said:


> I have a question about the change of the opamp in a DAC.
> According to your experience, how much the opamp swap will affect the SQ?


 
  
  


faber65 said:


> Alex,
> 
> Your reply does a lot of sense to me and it is not disappointing at all.
> I agree 100% with you, and I have experienced on that by swapping opamps on the Burson Lycan, as that was the purpose of that amplifier.
> ...


 
  
 Hello, 
  
 Basically, sound gets "recreated" in following stages:
 - I/V converter (DAC)
 - Low Pass Filter (DAC)
 - Voltage Amplification Stage (amplifier)
 - EQ or Loudness or any sort of sound correction/processing stage (amplifier)
  
 So, any opamps swapped in one of the above stages may alter the sound, more or less. Usually, first thing to do when choosing the right opamp to upgrade with is comparing the specs; also, don't swap low-bandwidth opamps with high-bandwidth ones, because you't know if you have enough decoupling caps installed and also your PCB may not perform admirable too. 
  
 As sometimes best sounding opamp is the one that oscillates more, please check for oscillations at the end of the upgrade. Have a read above:
 - http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html
 - http://www.diyaudio.com/forums/analog-line-level/278732-example-op-amp-oscillation-pics.html
 - http://www.diyaudio.com/forums/solid-state/153368-how-measure-op-amp-oscillation.html
 - http://www.analog.com/media/en/training-seminars/tutorials/MT-101.pdf


----------



## Nurgayan

In addition to the above, it can be said that minimizing components is the most logical action to improve the quality of the output signal.


----------



## Faber65

raoultrifan said:


> faber65 said:
> 
> 
> > I have a question about the change of the opamp in a DAC.
> ...




Thank you and all the others for your replies.


----------



## Renfield1217

​Hi Faber65,
  
 Does anyone know if the Burson V5i's have decoupling caps built into the circuitry of the opamp?
  
 Thanks
  
 Ren


----------



## raoultrifan

Hi, 
  
 No caps in there and I don't think there are any opamps with decoupling caps included. Usually, schematic design engineers should take care of these caps, based on calculations and measurements done (depending on the PCB layout and implementation, PSU ripple & noise, external EMI/RFI interferences etc.). So, who designs the equipment should choose the correct cpas value and type.
  
 See you!


----------



## Renfield1217

​Thanks raoultrifan,
  
 And agreed that the card manufacture should designate, but Burson sells their own caps for decoupling.
  
 Ren


----------



## Minbeo

Hi, PLZ Help  i wanna to do obca mod on some NE5534, i look around but unable to find a specific guide for this, which one is obca? which one is buffer mod??? Can somebody shed some light on this, thanks very much!


----------



## Audio Addict

Has anyone compared the Dexa SE with the Sparkos Labs SS3601/02?


----------



## Minbeo

Hi guys, i did output bypass mod for my Ne5534 following this guide http://rockgrotto.proboards.com/thread/4716 (minus the class A resistor mod). But when when put them on I/V stage of my dac, sound got terribly distorted. Anyone got idea what happens? tkss


----------



## rellik (Jun 2, 2017)

The opamp chip is overloading the output of your DAC chip as well as overdriving itself (terribly distorted vs distorted). Please include a driver stage and or buffer chip to minimize this effect. Often OP AMps will self bypass their output stages to an extent when properly loaded.

Some wish to completely define this them selves as per the rockgrotto link yet require special design. Preferably not post DAC. I/V conversion requires the integration of varying minute charge levels ("current") to a locked voltage which can be given a proper reference without destruction.

Link to: https://www.head-fi.org/f/threads/home-made-iems.430688/page-438#post-13525927 Post #6557 Most OP-amps internal stages work closer to the I of the V side of the I/V conversion. (2-3mA) A serious high input resistance FET loaded into parallel FETS with more leeway(integration room) can handle this. 
The benefit of this is to retain the signature of a favorite op amp/DAC while adding speed. The same function can be used on Op Amp inputs as well.

Either that or make sure that the output is exactly the same, always, at the same amplitude and loading.


----------



## Audio Addict (Jun 3, 2017)

Audio Addict said:


> Has anyone compared the Dexa SE with the Sparkos Labs SS3601/02?



Well since no one indicated any comments on the Dexa SE, I took one for the group.  I picked them up today and put a pair of singles in my Lycan.  I bought a quad for my RSA Apache but wanted to roll them first in the Lycan.

They are much taller than I expected.  Each SE has 3 green LED which I presume is to show they are working.

I have music running through this pair but a really quick impression with the HE400i, was they had a great midrange on a Diana Krell song from Turn Up the Quiet.  I look forward to spending more time once they have settled in.


----------



## Audio Addict

Audio Addict said:


> Well since no one indicated any comments on the Dexa SE, I took one for the group.  I picked them up today and put a pair of singles in my Lycan.  I bought a quad for my RSA Apache but wanted to roll them first in the Lycan.
> 
> They are much taller than I expected.  Each SE has 3 green LED which I presume is to show they are working.
> 
> I have music running through this pair but a really quick impression with the HE400i, was they had a great midrange on a Diana Krell song from Turn Up the Quiet.  I look forward to spending more time once they have settled in.



Just opened my Apache and there is no way the Dexa SE will fit.  The are just way too tall.


----------



## zilch0md

Audio Addict said:


> Just opened my Apache and there is no way the Dexa SE will fit.  The are just way too tall.



I know the feeling!


----------



## Audio Addict

I have a quad of SSA v5 with the extension legs but it was too severe of a angle and one the legs broke.
Right now I have a pair of the Dexa SE Singles in my Lycan that is driving my HE6 unbelievable well.  The DAC is the LH Labs Pulse X Infinity v2.0 using the Burson Audio RCA Cable Pro to the Lycan.  Roon is feeding DAC.  The current music is from Guardians of the Galaxy Vol. 2

I honestly wish I could try them in my Apache given how well they are driving the HE6s with excellent sonics.


----------



## rellik

Diana Krall is quite impressive, I thought it was a synthesized vocal and piano...maybe not. Hard to tell when the amp has a mind of its own.

Same goes for (The Real Folk Blues)


----------



## rikk009

How does LM4562NA sound different to LME49990? I have the former in Matrix hpa-1 and was wondering if it's worth swapping for the later one?


----------



## santodx5

Hi Guys,

I am planning to try Muse 8820, does anyone know a good store in ebay? Im oversea and usually shipping from USA will be more expensive.

Thanks


----------



## Origen Ru

Anyone know if my LITTLE BEAR B2 portable amplifier that uses a OPA JRC 4556 AD  is compatible with OPA MUSES 02?


----------



## golov17 (Jun 18, 2017)

Origen Ru said:


> Anyone know if my LITTLE BEAR B2 portable amplifier that uses a OPA JRC 4556 AD  is compatible with OPA MUSES 02?


https://www.head-fi.org/f/threads/little-bear-b-2-portable-amp.654211/


----------



## Origen Ru

golov17 said:


> https://www.head-fi.org/f/threads/little-bear-b-2-portable-amp.654211/



Exactly those are, Do you know if I can put the muses02 in the little bear B2 amplifier?


----------



## golov17

Origen Ru said:


> Exactly those are, Do you know if I can put the muses02 in the little bear B2 amplifier?


Why not?


----------



## Origen Ru (Jun 18, 2017)

golov17 said:


> Why not?


I have two years with my lettle bear B2 that included the OPA JRC 4556 AD, the same OPA that uses the amplifier GRADO AR1, my headphones are the Alessandro MS2e, it is for the OPA JRC 4556 AD I buy it, I do not know the compatibilities with other OPA's That's why I ask if I can use the MUSES 02 that I buy for my future Zishan DSD player, to burn the MUSES 02 using it in my LITTLE BEEAR B2 in what I get the player.


----------



## golov17

Origen Ru said:


> I have two years with my lettle bear B2 that included the OPA JRC 4556 AD, the same OPA that uses the amplifier GRADO AR1, my headphones are the Alessandro MS2e, it is for the OPA JRC 4556 AD I buy it, I do not know the compatibilities with other OPA's That's why I ask if I can use the MUSES 02 that I buy for my future Zishan DSD player, to burn the MUSES 02 using it in my LITTLE BEEAR B2 in what I get the player.


Same OPA architecture, you can


----------



## Oscar-HiFi

Just got some Burson V5i's in for my Topping A30, limited space so the regular V5 wouldn't fit. Now to run them in, the original opamps were OPA2134. This amp has come alive, black background, wide soundstage and better bass texture.


----------



## golov17

I love v5i too


----------



## ostewart

Burson V5i review up: https://www.head-fi.org/f/showcase/burson-audio-supreme-sound-opamp-v5i.21562/reviews#review-18847


----------



## golov17

I would like to one day try pair singles Burson v5i with my amp
 from VE..


----------



## Faber65

Guys, it seems that there is a newborn baby in Burson family, or better two. 
Have a look. 

https://www.bursonaudio.com/products/supreme-sound-opamp-v6/

And it seems that there is a launch offer for the early birds.


----------



## pelopidas

rikk009 said:


> How does LM4562NA sound different to LME49990? I have the former in Matrix hpa-1 and was wondering if it's worth swapping for the later one?


The 49990 is more balanced in its presentation. More detail and more pleasant than the 4562. Makes the 4562 feel overly bright and shouty in comparison. The 49990 is a step up.


----------



## pelopidas

Faber65 said:


> Guys, it seems that there is a newborn baby in Burson family, or better two.
> Have a look.
> 
> https://www.bursonaudio.com/products/supreme-sound-opamp-v6/
> ...


You beat me to it! Two new V6 to choose from. One is supposed to more dynamic and detailed than the V5 and the other more musical? This will be interesting. Now we will have to start playing with the correct placement of each opamp. Which one for buffer vs I/V?


----------



## golov17

Faber65 said:


> Guys, it seems that there is a newborn baby in Burson family, or better two.
> Have a look.
> 
> https://www.bursonaudio.com/products/supreme-sound-opamp-v6/
> ...


Thanks, waiting v6i


----------



## leeperry

Cool story but V5 already comes with "Reverse Voltage Protection", it's pretty appalling that the opamp itself apart from the extra socket it ships with doesn't come with any way to find out where pin 1 is, bleh.

All this said OPA602BP still does the magic


----------



## golov17

leeperry said:


> doesn't come with any way to find out where pin 1 is, bleh.


Hmm..


----------



## leeperry (Jul 15, 2017)

sure thing but that's the removable extra socket that's fitted on top of the actual opamp pins, once it's off you can't tell where pin 1 is and it'll easily get stuck in your host so you'll end up with an opamp that doesn't show any indication of where pin 1 is. I guess putting a "1" on the bottom of the PCB was too much to ask.

truth is I got mine second hand from a n00b who fitted back that extra socket backwards by mistake so I found out first hand that v5's come with reverse voltage protection


----------



## Burson Audio

leeperry said:


> sure thing but that's the removable extra socket that's fitted on top of the actual opamp pins, once it's off you can't tell where pin 1 is and it'll easily get stuck in your host so you'll end up with an opamp that doesn't show any indication of where pin 1 is. I guess putting a "1" on the bottom of the PCB was too much to ask.
> 
> truth is I got mine second hand from a n00b who fitted back that extra socket backwards by mistake so I found out first hand that v5's come with reverse voltage protection



Hi Guys, Hi Leeperry, 

Thank you for your long term support for both Burson Audio and head-fi.org 

Please allow us to clarify the below.

* The Burson V5 audio opamp does NOT have the reverse plug-in protection.  Being a discrete opamp, its components may tolerate an incorrect installation longer than any IC opamps but it will fail and could even post a risk to your machine.  And such damages will not be covered by its life-time warranty.  

* The Burson V6 does have the reverse plug in protection. : ) 

* Both the V5 and V6 have clear indication of pin 1 and we don't just rely on their detachable DIP8 socket.

Please refer to the chart below for correct installation steps.  The same chart is also featured on both V5 and V6 product pages.


----------



## leeperry

Hi there, well my V5 was still alive after being reversed for a few secs giving some loud buzzing.

Fair enough but in my case the extra socket that's fitted in order to protect the actual opamp pins had been reversed by mistake and I wasn't aware that it was even there and assumed that these were the actual pins of the opamp. A clear "1" somewhere like on the bottom of the PCB would have helped a lot in my case.


----------



## trybeingarun

Hey guys. I have a matrix m-stage hpa-3u+ which has a LME49860. I find the sound coming out of the matrix to be a bit soft with low dynamics and attack compared to my Aune X1s unit. It could be that the implementation of the matrix is slightly inferior. I am also interested in rolling opamps, but I have to admit I don't know much about them. Are there any drop in replacements for LME49860 that I can use safely, without changing voltage regulators? The spec sheet says 49860 swings +-22V. I would also like a slightly brighter opamp, if there's a choice.


----------



## golov17

@Burson Audio 
Do you plan to release v6i?


----------



## rikk009

pelopidas said:


> The 49990 is more balanced in its presentation. More detail and more pleasant than the 4562. Makes the 4562 feel overly bright and shouty in comparison. The 49990 is a step up.


Just received LME49990 and maybe it's my head playing with me but highs might be just a little bit more clear, just listened to a few songs only. Just...


----------



## endia

does anybody have any info about these opamps?

https://goo.gl/CA4mDP
https://goo.gl/GX5eNB
https://goo.gl/ZDfEQW

did a google search but no english result but chinese.. they seem quiet popular and have well reputation altough some of them pretty expensive..
thanks in advance..


----------



## pelopidas

rikk009 said:


> Just received LME49990 and maybe it's my head playing with me but highs might be just a little bit more clear, just listened to a few songs only. Just...


The 49990 is more detailed and also has better bass. There is a mod that you need to try with it. You need to put a Silmic 10uf capacitor onto its power pins. The easiest way is to use another socket. The Silmic must have 100 hours burn in. It sounds fantastic for the first 2 hours, then sounds kinda terrible for 20 - 60 and finally is settled at 100 hours. This mod is worth it with the 49990.


----------



## pelopidas

endia said:


> does anybody have any info about these opamps?
> 
> https://goo.gl/CA4mDP
> https://goo.gl/GX5eNB
> ...



My guess is they are fakes. HDAM is an acronym for - hyper dynamic amplifier module - a term used by Marantz to describe their pre opamp circuits. SS3601/2 is a Sparkos designation for their opamps. And the PHILPS at the bottom does not inspire any more confidence. Most likely rebranded 49720/49710HA if you are lucky. Maybe something crappier. If they were legit and good there would be more info out there.


----------



## endia

pelopidas said:


> My guess is they are fakes. HDAM is an acronym for - hyper dynamic amplifier module - a term used by Marantz to describe their pre opamp circuits. SS3601/2 is a Sparkos designation for their opamps. And the PHILPS at the bottom does not inspire any more confidence. Most likely rebranded 49720/49710HA if you are lucky. Maybe something crappier. If they were legit and good there would be more info out there.



pelopidas, thank you.
lol, didn't notice product's name containing another brands'..


----------



## Rroff

pelopidas said:


> The 49990 is more detailed and also has better bass. There is a mod that you need to try with it. You need to put a Silmic 10uf capacitor onto its power pins. The easiest way is to use another socket. The Silmic must have 100 hours burn in. It sounds fantastic for the first 2 hours, then sounds kinda terrible for 20 - 60 and finally is settled at 100 hours. This mod is worth it with the 49990.



Seems to be the case with all those LME and the LM4562 - 10uf rail to rail definitely has some impact on the audio reproduction - when I used a silmic ii though it seemed a bit "DSP" like to me (not necessarily a bad thing depending on what you want) while a Nichicon KZ seemed to help with more transparency. Those opamps while generally high performance seem a touch susceptible to acting a bit oddly from power supply noise which I think is what this cap helps to offset.


----------



## leeperry

The AMP9920AT is very funny stuff, it's a cheapo SOIC8 chip(5532 IIRC) fitted in a T099 case at premium price, you can find pics of it being cracked open on google.


----------



## endia

leeperry said:


> The AMP9920AT is very funny stuff, it's a cheapo SOIC8 chip(5532 IIRC) fitted in a T099 case at premium price, you can find pics of it being cracked open on google.



lol, funny indeed..


----------



## leeperry

It's your lucky day, PM search finally works again so here goes: https://www.jdbbs.com/thread-5699748-1-1.html


----------



## rikk009

pelopidas said:


> The 49990 is more detailed and also has better bass. There is a mod that you need to try with it. You need to put a Silmic 10uf capacitor onto its power pins. The easiest way is to use another socket. The Silmic must have 100 hours burn in. It sounds fantastic for the first 2 hours, then sounds kinda terrible for 20 - 60 and finally is settled at 100 hours. This mod is worth it with the 49990.


Hmmm...thanks. After  AB comparing both 49990 and 4562 I can hear 49990 has more clarity and better control on bass, highs extended further and more dynamic, worth the upgrade. Also it came to me with broken DIP socket so will give the cap mod a try when I get a new DIP.

Btw, I noticed a LME49850 being used in my DAC which yield nothing when googled. Any idea? I have heard about 49860 but this says 49850.


----------



## chaiyuta (Jul 24, 2017)

After I surf internet to find information about MUSES03. It seems the cheapest price (2500 Yen or 23$USD) is at only Japan. MUSE03 is really hit in Japan. MUSES03 has run out of stock 3 times, and everytime they do re-stock. It takes approximately 1 month.
Info Link : Here (You can use google translate for reading)
MUSES03 Review Link : Here (You can use google translate for reading)
OPA627AP vs MUSES03 review Link : Here (You can use google translate for reading)

Hope you enjoy these articles I found. hehe

One question : Do you guys have any recommendation of DAC/AMP or AMP that can use 2 x single op-amp MUSE03 {and have 2.5mm BL output and BL input (preferred if possible)}?


----------



## golov17

http://akizukidenshi.com/catalog/g/gI-11843/


----------



## chaiyuta

@golov17 : Yes, 2 days ago. Its stock has 45 pcs. left. and now (at the time I posted) Its stock becomes 35 pcs. left. For those who are login (and register as member) can see. I guess at the end of this month. MUSE03 would be out of stock again.


----------



## earfonia

chaiyuta said:


> After I surf internet to find information about MUSES03. It seems the cheapest price (2500 Yen or 23$USD) is at only Japan. MUSE03 is really hit in Japan. MUSES03 has run out of stock 3 times, and everytime they do re-stock. It takes approximately 1 month.
> Info Link : Here (You can use google translate for reading)
> MUSES03 Review Link : Here (You can use google translate for reading)
> OPA627AP vs MUSES03 review Link : Here (You can use google translate for reading)
> ...





golov17 said:


> http://akizukidenshi.com/catalog/g/gI-11843/



Thanks for the links! I didn't know Muses already launched Muses03. Curious to try.

Btw, I recently reviewed the Burson V5i here:
https://www.head-fi.org/f/showcase/burson-audio-supreme-sound-opamp-v5i.21562/reviews#review-18921

Curious to compare it with the Sparkos and Muses03.


----------



## numon

hi
which opamp for zishan z2  that  has the best widest soundstage ?
i have rose mojito earbud.


----------



## leeperry

earfonia said:


> https://www.head-fi.org/f/showcase/burson-audio-supreme-sound-opamp-v5i.21562/reviews#review-18921



Funny how the owner of Violectric likes to be patronizing about the fact that rolling stock 553x's would not improve sound quality, gg 

Personally I'm still very much in love with LT1028A, Ray Samuels called it the best for a reason. Too bad stupid thing isn't unity gain stable


----------



## leeperry

...and let's not mention OPA602BP, such a great chip in the right rig


----------



## rikk009

leeperry said:


> ...and let's not mention OPA602BP, such a great chip in the right rig


Alrite...Ordered one. Let's hope I get it(prays to Custom Gods) and it be a genuine one.


----------



## leeperry

got them for free off TI a while ago but I think their sample program got tougher since then.


----------



## selvakumar

Using *Supreme Sound Opamp V5i *with* ASUS SUPREME FX HI-FI DAC *its epic


----------



## selvakumar

Burson has just released what they called the perfect "opamp rolling platform" allowing up to 5 opamps to roll.

https://www.bursonaudio.com/products/play/

Obviously, Burson is using it to promote their opamps but not sure if it can be used to roll and test other IC opamps and discrete opamps too?


----------



## Audio Addict

selvakumar said:


> Burson has just released what they called the perfect "opamp rolling platform" allowing up to 5 opamps to roll.
> 
> https://www.bursonaudio.com/products/play/
> 
> Obviously, Burson is using it to promote their opamps but not sure if it can be used to roll and test other IC opamps and discrete opamps too?



You should be able to roll opamps.  I talked with them before ordering my Play.  The DAC uses 3 dual and the amplifier uses 2 singles.  The 3 duals will make it more expensive to roll but that is really their intentions.


----------



## FritzS

selvakumar said:


> Burson has just released what they called the perfect "opamp rolling platform" allowing up to 5 opamps to roll.
> 
> https://www.bursonaudio.com/products/play/
> 
> Obviously, Burson is using it to promote their opamps but not sure if it can be used to roll and test other IC opamps and discrete opamps too?



The bad news for me, Play don't offer additional analog inputs too.
Gives any Burson HA, like Play with additional analog inputs.
And additional TOSLIK  S/PDIF inputs are a nice feature too.

All class-A are my choice.


----------



## rikk009

DOWN THE SPIRAL HOLE...


----------



## selvakumar

Audio Addict said:


> You should be able to roll opamps.  I talked with them before ordering my Play.  The DAC uses 3 dual and the amplifier uses 2 singles.  The 3 duals will make it more expensive to roll but that is really their intentions.


ok lets see i preordered play


----------



## Audio Addict

selvakumar said:


> ok lets see i preordered play



I will have 3 dual vivid's in the DAC section and plan to try several different singles  such as the V5 and V5i in the amplifier section.


----------



## rikk009

Why not take specific product discussion to the dedicated thread?


----------



## selvakumar

guys any one tested LME49720


----------



## Audio Addict

rikk009 said:


> Why not take specific product discussion to the dedicated thread?



Sorry for confusion.  The purpose of this device is to allow opamp rolling.  I look forward to hearing the new Vivid V6 in the DAC.  I have several different opamps to roll in the amplifier section.

I will keep comments focused on the opamps in the future.


----------



## imran27

Has anyone tried any of these opamps?

OPA1622
OPA1692
OPA2625
--
Thanks,
Imran


----------



## Oscar-HiFi

selvakumar said:


> guys any one tested LME49720



I've used it in cmoy type amps before, and it became one of my favourites, very detailed airy and neutral. Not laid back like some of the OPA2227 type op-amps.


----------



## leeperry

imran27 said:


> Has anyone tried any of these opamps?
> 
> OPA1622
> OPA1692
> OPA2625


I've snatched a few 1622 modules and will be trying them in my headamps shortly


----------



## imran27

Anybody tried the OPA1688? The small signal step response looks like crazy good and I love the CMOS type opamps, they have a very detailed sound.


----------



## raoultrifan

Hi, I've seen some fox trying it out and one of them would be Alex:

https://www.head-fi.org/threads/the-opamp-thread.432749/page-361#post-12947484


----------



## escknx

Anyone compared Sparkos vs Burson V6?


----------



## raoultrifan

No, not tested Sparkos yet, sorry.

However, I did tested the newest V6 Classic, in case yo're interested into: https://www.head-fi.org/threads/bur...ssion-and-reviews.854912/page-9#post-13830420.


----------



## Audio Addict

escknx said:


> Anyone compared Sparkos vs Burson V6?



I have the SS3602 and I just received Friday the Vivid V6 and the Classic V6.  I haven't compared them all together but in the Vivid versus the Classic I preferred the Classic as it was more engaging but the Vivid is very detailed and dynamic. This was listening using the Burson Lycan to roll the amps.  I do like the Sparkos but recently have been using the Dexa SE: and found I like it more than the Burson V5.  Right now, I am not sure in a comparison to the new V6.  I would say now it is mostly a pure preference.

I use a quad of the Sparkos SS3601 in my RSA Apache.  The Burson's were too tall to fit in the Apache.  Though I do like the SS3601 in my Apache driving the Utopias.  I tried the Dexa SE but they also turned out to be too tall for the Apache.


----------



## Mad Max

Any of you guys tried the Panasonic ECHU film caps to decouple opamp PSU rails?


----------



## j4100

I'm venutring out of my comfort zome in here, but hoping for some advice. I'm looking at a budget Chinese portable amp, the Jazz R7.0 and noticed it seems to be popular for modification, not least op amp rolling. The R7.0 is listed as having OPA2604AP and the R7.8 has MUSES8920. Would you reckon it's worth the extra getting the R7.8, or just go with the R7.0? 

Jazz R7.0 Link
https://www.aliexpress.com/store/pr...470.html?spm=2114.12010612.0.0.26409ed6wC5nVp
Jazz R7.8 Link
https://www.aliexpress.com/store/pr...140.html?spm=2114.12010612.0.0.4b99afbdPEhKGW


----------



## bunkbail (Nov 18, 2017)

I've read about using bypass capacitors like the Elna Silmic II alongside the opamps would be beneficial in SQ. Would it be the same for Burson V6 opamps on a Gustard H10 amp?


----------



## raoultrifan

Yes, especially if you have no good caps already installed for that.
However, BURSON is recommending this too: https://www.bursonaudio.com/burson-ss-opamp-101-part-1-mkp-cap-tweak/


----------



## bunkbail

raoultrifan said:


> Yes, especially if you have no good caps already installed for that.
> However, BURSON is recommending this too: https://www.bursonaudio.com/burson-ss-opamp-101-part-1-mkp-cap-tweak/


That is helpful. Thanks.


----------



## sup27606

Dear community members,
I am having some serious noise issues with opamp swapping. I am trying to use two Burson V5i-d opamps in the Nobsound NS-08e amp by swapping with the original NE5532s. I am hearing a lot of noise through the headphones.

There are two kinds of noises, one is a low whistle (about 1Khz I would say) and the other a hissing sound. 
The hissing sound changes when I move around the headphone cable, while the whistle remains unchanged. 
There is no difference in noise between the two channels (each channel uses a separate opamp).
The noises are unaffected by connecting/disconnecting the source DAC. 
I am also hearing some distortion at selected regions in the soundtracks. 
I tried changing the power adapter and the noise remains at similar levels for the different adapters I tried.
Tried using different pair of tubes with no difference in noise characteristics.

Using a battery pack, the amp was completely silent. So there must be power noise which the opamp chips are extremely sensitive towards. This is surprising to me since people in the Nobsound thread report no noise issues while using these opamps.

The original NE5532s are completely silent with no noise. 

Can someone give me some instructions to troubleshoot / diagnose this. I want to know, whether the chip is faulty. I have a digital multimeter.

Many thanks in advance.


----------



## raoultrifan

Hi there, 

V5i had some compatibility issues with some amplifiers when used in Voltage Amplification stage, also with my HPA-3B had some issues too: https://www.head-fi.org/threads/int...review-to-follow.770610/page-15#post-13092204. However, I strongly recommend you SS V6 or SS V5 instead of V5i; you'll get noise free perfect sound.

Good luck!


----------



## Audio Addict

raoultrifan said:


> Hi there,
> 
> V5i had some compatibility issues with some amplifiers when used in Voltage Amplification stage, also with my HPA-3B had some issues too: https://www.head-fi.org/threads/int...review-to-follow.770610/page-15#post-13092204. However, I strongly recommend you SS V6 or SS V5 instead of V5i; you'll get noise free perfect sound.
> 
> Good luck!



That explains why I could not get the v5i to work in my Lycan.  I also tried a quad in my RSA Apache and it wasn't a synergy.  The V5i was created most likely to solve the space issue compared to the regular V5.  I know that was the reason I got a quad asI tried the V5 with the leg extensions but the extreme angle ultimately caused a failure in one of the leg extensions.


----------



## selvakumar

sup27606 said:


> Dear community members,
> I am having some serious noise issues with opamp swapping. I am trying to use two Burson V5i-d opamps in the Nobsound NS-08e amp by swapping with the original NE5532s. I am hearing a lot of noise through the headphones.
> 
> There are two kinds of noises, one is a low whistle (about 1Khz I would say) and the other a hissing sound.
> ...


V5i-d may need RMA contact Burson Audio


----------



## sup27606

Thank you all for your replies. I see now, there have been other instances of noise reported as well. Unfortunately, I cannot use the full sized V5/6 due to space constraint, so V5i is the only option for me. Also, I am in talks with Burson Audio over this.


----------



## selvakumar

sup27606 said:


> Thank you all for your replies. I see now, there have been other instances of noise reported as well. Unfortunately, I cannot use the full sized V5/6 due to space constraint, so V5i is the only option for me. Also, I am in talks with Burson Audio over this.


post the replies of Buson Audio


----------



## sup27606

selvakumar said:


> post the replies of Buson Audio



I am in contact with Dennis from Burson Audio. He asked me to try several things such as using only one V5i instead of two, and measuring the voltage across pins 4 and 8. I measured the voltage to be 23.9V which was in the normal range. Also, keeping only one V5i and replacing the other with the old NE5532 significantly reduced the noise, although didn't completely removed it.

However here is the really bizarre part. With the two Bursons in place, I was hearing a lot of static in my headphones. Also when I moved around the headphone cable, the static changed in intensity. The static turned out to be radio signal, because today I was able to hear FM transmission through my headphones! I even heard a commentator say 101, so I know the station captured is near 101 MHz. My wife heard it as well. Clearly, with the Bursons in place, the headphone cable is acting as a receiver antenna and all that static was radio interference. How that signal is getting amplified to be audible through the headphones is beyond me. I don't have enough electronics knowledge to figure that out. I am writing to Burson Audio about this.


----------



## raoultrifan

Like several other opamps, V5i may not be compatible with all amps out there. Like I said before, my Matrix HPA-3B didn't quite liked the V5i much and I was reading here on Head-Fi that other head-fiers had issues with other amps model (feel free to search for yourself).

You might be able to solve it if you're willing to adjust the gain of your amp.


----------



## sup27606 (Nov 23, 2017)

raoultrifan said:


> Like several other opamps, V5i may not be compatible with all amps out there. Like I said before, my Matrix HPA-3B didn't quite liked the V5i much and I was reading here on Head-Fi that other head-fiers had issues with other amps model (feel free to search for yourself).
> 
> You might be able to solve it if you're willing to adjust the gain of your amp.



I agree with you, but the thing is, several others have successfully used the V5i in the amp model that I am using and none of them faced any noise issue (I got the V5is based on their recommendation). https://www.head-fi.org/threads/nobsound-ns-08e-also-know-as-nobsound-6j9-hybrid-tube-amp.794796/
 It doesn't seem like, my particular amp has any electrical defect either, since the old opamps work just fine. I am considering burning them in for several days to see if subtle changes in their electrical characteristics can improve the noise issue. I am curious about the V6 and may consider getting a Matrix amp in the future to try them (I hope the V6 fit inside them with the cover closed). The Sennheiser 6XX sound really sweet with these opamps.

How do you adjust the gain of the amp (there is no gain switch)?


----------



## sup27606

Seems like interference in both power chord and headphone cable. Will try adding a couple of ferrite cores to see if that solves the issue.


----------



## selvakumar

sup27606 said:


> Seems like interference in both power chord and headphone cable. Will try adding a couple of ferrite cores to see if that solves the issue.


you are right use some ferrite cores and post the update


----------



## sup27606

selvakumar said:


> you are right use some ferrite cores and post the update



Using ferrite cores on both the power chord and the headphone cable (Sennheiser factory one) eliminated the noises almostly entirely. Now, there is a very low level noise that is only detectable in absolute silence. I had to use two ferrite cores each on the cables. However, the ferrite cores didn't help at all with my Sennheiser cable from ZY cable. This cable picked up loud FM interference and was unchanged with ferrites. Anyhow, I am now a lot more satisfied with the amp and probably will keep the opamps.


----------



## ph0n6

Back when I was testing the V5i I had similar issues too, but to know that they might be radio signals is quite interesting.


----------



## bunkbail

Are the LME49720 dual op-amps in the Gustard H20 amp can be swapped to discrete op-amps like the SS3602 or the Burson V6?


----------



## imran27

Tried all the opamps quickly today on my XD-05

*OPA1602*
Tube sounding opamp. Not quite replaceable with tubes but pretty close. The typical reverb (or harmonics) is present, treble is really sweet. This one is the most pleasurable to listen. But not accurate and precise, certainly not that detailed. Bass depth is average, or maybe below average. Treble extension is unnoticeable if it is present even. Mids are forward, really nice and smooth.

*OPA1652*
Smooth, details not satisfactory. Neutral, very thick sounding. Bass depth is noticeably nice, treble extension is better than the OPA1602. It's actually a toss between this and opa1602, for different moods. They are both quite different.

*OPA1642*
This is the one that gets closest to LME49720. It's very confusing to compare these two. One thing is clear though, lme49720 is more precise and accurate in terms of imaging and placement. Also, lme49720 seems to have better and more extended highs. But I need more time to get conclusive on this opamp. It looks promising. It has the same level of clarity as lme49720. For now, I have replaced lme49720 with opa1642 to get more detailed impressions.

As of now, LME49720 & OPA1642 are the 2 best in my XD-05.


----------



## Rroff

I've never found a setup where at times you don't catch the OPA1602 struggling with articulation - its minor but just enough to be displeasing - a shame as otherwise an excellent imitation of a tube a like sound.

Out of that OPA16xx line I prefer the OPA1612 while a little synthetic sounding especially at first and a very touch light on the bass it is detailed and clear and I've never heard any problems with articulation, etc. those preferring a warmer sound and/or a bit more rich "musicality" might not like it though. I actually prefer it to the LME49720 as while it doesn't quite have the clarity due to being a touch smoother it doesn't have that slight metallicness for want of a better way to put it as the LME.

Personally I end up going back time and time again to the AD8066 with the right capacitors around it it just has everything I want.


----------



## leeperry

Rroff said:


> Out of that OPA16xx line I prefer the OPA1612


Sounds like you didn't try 1622


----------



## imran27

My XD-05 is dc coupled with BUF634, so it sounds different from capacitor coupled circuits.

In my XD-05, LME49720 and OPA1642 sound better than OPA1612. 1612 to me has boosted sub bass, makes instruments sound a bit more hefty

My stock XD-05 was all great with 1613 until I swapped it out for LME49720, it's just more linear, natural and has edge at details and clarity, at least in a perceivable way. 1612 had a very laid back boosted sub bass which hampered with detail perception and soundstage a lot.

In fact in the OPA16xx series OPA1642 is better in my setup.


----------



## rikk009

imran27 said:


> My XD-05 is dc coupled with BUF634, so it sounds different from capacitor coupled circuits.
> 
> In my XD-05, LME49720 and OPA1642 sound better than OPA1612. 1612 to me has boosted sub bass, makes instruments sound a bit more hefty
> 
> ...


Folks at MD were gaga over V5i in XD-05.


----------



## Rroff (Dec 1, 2017)

leeperry said:


> Sounds like you didn't try 1622



I've not seen the 1622 in a DIY friend format yet - though I've heard interesting things about it. Local place only has it in VSON which I'm not setup to solder though I suspect I could probably manage to jury rig it 



imran27 said:


> My XD-05 is dc coupled with BUF634, so it sounds different from capacitor coupled circuits.
> 
> In my XD-05, LME49720 and OPA1642 sound better than OPA1612. 1612 to me has boosted sub bass, makes instruments sound a bit more hefty
> 
> ...



Ah the BUF changes things a bit - surprised about the 1612 though in all my implementations it has if anything been a touch lacking on the sub-bass front but only slightly.


----------



## NymPHONOmaniac

Hi there, anybody know a really TRUSTABLE Aliexpress seller for OPamp ???

Too much confusing comment....about fake stuffs. I search the best 2-15$ OPamp for swaping in Walnut V2 and a external DAC-AMP.

Thanks in advance to help here, so I will not fall in traps....was eying LM4502 or Muse8920 or 01-02....(OP-newbie here!)


----------



## olymind1

Hi!

I am trying to find a better opamp for my Auzentech X-Fi Prelude card which uses *AKM-4396VF *DAC and *LM4562NA* opamp. I read, i read and read, and now i'm starting to see the light at the end of the tunnel:

*LME49860NA
LME49990MA*

I liked what i read about the *LME49720HA* too (or 2x *LME49710HA*), but saw complaints about the highs having troubles. What about the *LME49990MA*? While the *LME49860NA *seems to be more balanced overall.

Is there anyone here who use all 3 of them?


----------



## rikk009

olymind1 said:


> Hi!
> 
> I am trying to find a better opamp for my Auzentech X-Fi Prelude card which uses *AKM-4396VF *DAC and *LM4562NA* opamp. I read, i read and read, and now i'm starting to see the light at the end of the tunnel:
> 
> ...


*720 slow and good for mids, *990 faster and more lively


----------



## ScottFW

olymind1 said:


> I am trying to find a better opamp for my Auzentech X-Fi Prelude card which uses *AKM-4396VF *DAC and *LM4562NA* opamp. I read, i read and read, and now i'm starting to see the light at the end of the tunnel:
> 
> *LME49860NA
> LME49990MA*



I don't know anything specifically about your sound card, but my Audioengine D1 has the AK4396 DAC with just one dual-channel opamp driving either the line outs or headphone jack.

Presumably you are aware that the LM4562 and LME49860 are dual channel opamps, but the LME49990 is a single. So if you're trying to sub in for a dual, you would need to solder two of those to an adapter. I have run LME49990 both as singles and on dual adapters in a few CD players and in the Audioengine D1 and it's a great choice.

Another really good option is the OPA1688. I'm hard pressed to notice much/any difference in sound quality compared to 2x LME49990 strapped to a dual adapter, and the OPA1688 being 2-channel is more of a direct swap, plus it provides more output current which is beneficial if it's going to be driving headphones directly.


----------



## raoultrifan

I don't care about their datasheet, but to my ears *LME49860NA* is noisier than *LME49720HA*.

*LME49990MA*, besides that is single and needs very good quality PCB to adapters, it could oscillate with ease, so depending on how it's built your Auzentech could be needed additional decoupling caps (fast multilayer 0.01-0.1uF + 1uF tantalum should probably do). 

Without additional decoupling you could also try MUSES 8920 or MUSES 01, but also something from Burson that could feet your computer's case (V6 if possible).


----------



## olymind1 (Dec 14, 2017)

ScottFW said:


> I don't know anything specifically about your sound card, but my Audioengine D1 has the AK4396 DAC with just one dual-channel opamp driving either the line outs or headphone jack.
> 
> Presumably you are aware that the LM4562 and LME49860 are dual channel opamps, but the LME49990 is a single. So if you're trying to sub in for a dual, you would need to solder two of those to an adapter. I have run LME49990 both as singles and on dual adapters in a few CD players and in the Audioengine D1 and it's a great choice.
> 
> Another really good option is the OPA1688. I'm hard pressed to notice much/any difference in sound quality compared to 2x LME49990 strapped to a dual adapter, and the OPA1688 being 2-channel is more of a direct swap, plus it provides more output current which is beneficial if it's going to be driving headphones directly.



Mine also has only 1 swappable opamp.
I'm doing some more reading about the *OPA1688* then.




raoultrifan said:


> I don't care about their datasheet, but to my ears *LME49860NA* is noisier than *LME49720HA*.
> 
> *LME49990MA*, besides that is single and needs very good quality PCB to adapters, it could oscillate with ease, so depending on how it's built your Auzentech could be needed additional decoupling caps (fast multilayer 0.01-0.1uF + 1uF tantalum should probably do).
> 
> Without additional decoupling you could also try MUSES 8920 or MUSES 01, but also something from Burson that could feet your computer's case (V6 if possible).



So then the *LME49860NA *not a good upgrade choice from *LM4562NA*.

It was considered to be a well built card 10 years ago, how well i don't know.

This is the card:






This is the 2x *LME49990 *soldered into a DIP8 socket what i looked out:
https://www.ebay.com/itm/One-2x-Mon...364823?hash=item4670c059d7:g:pPkAAOSwd4tTtCZP
^^ I know, ebay, but at least the seller is 100% trustworthy, not a single negative critic.

About discret Burson opamps, yes i know, probably it would be the safest and best course of action, just not the cheapest one, sadly. With taxes and import it prices 5 time more than the linked one. Even if i buy within the EU.


----------



## raoultrifan

My recommended budget opamp will always be MUSES 8920 if used in I/V stage and MUSES 8820 if used in LowPass or Voltage Amplification or Buffer stages.
I assume (not 110% sure) that the LM4562 is used as I/V converter in your soundcard, so I would anytime try the 8920. This is designed for audio-use, needs no additional decoupling and it's DIP8 too.


----------



## rikk009

olymind1 said:


> Mine also has only 1 swappable opamp.
> I'm doing some more reading about the *OPA1688* then.
> 
> 
> ...


That's interesting piece of hardware...is that one DAC chip per channel? 

I bought this one https://www.ebay.com/itm/1pcs-Dual-...OPA2604-NE5532-TL072-LME49990MA-/181118392690. Got genuine.


----------



## olymind1

rikk009 said:


> That's interesting piece of hardware...is that one DAC chip per channel?
> 
> I bought this one https://www.ebay.com/itm/1pcs-Dual-...OPA2604-NE5532-TL072-LME49990MA-/181118392690. Got genuine.



1 DAC per 2 channels, it's a 7.1 sound card, hence the 4 DACs, front channel's op amp is swappable and 3 *OPA2134ua*s for the remaining channels. By the way i like the LM4562NA clarity over the OPA2134, but maybe it has too harsh highs, i don't know. 

I looked that vendor / item too, but that shop sometimes sells fake ones. I would rather not risk it.



raoultrifan said:


> My recommended budget opamp will always be MUSES 8920 if used in I/V stage and MUSES 8820 if used in LowPass or Voltage Amplification or Buffer stages.
> I assume (not 110% sure) that the LM4562 is used as I/V converter in your soundcard, so I would anytime try the 8920. This is designed for audio-use, needs no additional decoupling and it's DIP8 too.



That i don't know how it works. Doesn't the 8920 have somewhat limited soundstage? At east that's what i read about it.

And how would i know if the 2 lme49990s would oscillate?


----------



## raoultrifan

olymind1 said:


> And how would i know if the 2 lme49990s would oscillate?



Usually by using the scope, but also if it's really hot after 10-15 minutes of operation (or if you hear radio-waves or strange wining sounds).


----------



## Rroff (Dec 15, 2017)

LM4562 though clear and detailed is very "clinical" and in my experience a bit susceptible to power supply noise making it "metallic" sounding - as mentioned earlier in this thread you can do wonders with it sometimes bridging the rails with a 10uf aluminium electrolytic capacitor like an Elna Silmic II or Nichicon FG or KZ - though potentially that is trading accuracy for a subjectively more pleasing sound. That likely depends a bit at what stage in the pipeline it is used and how.

Personally not a fan of the OPA2132/2134 it is accurate enough but somehow it sounds like someone playing the same tune for the 1000th time with none of the passion and nuance of when they enjoyed playing it.

I'm actually quite a big fan of the OPA2228 over the 2134 but its only stable at higher gains so would need intimate knowledge of the circuit it was going into and quite fussy about the capacitors around it i.e. if there are ones used to limit bandwidth in the feedback loop, etc. and so on to sound good - a lot of people end up with a "grungy" sound because it can't just be dropped into the circuit they are using.


----------



## NymPHONOmaniac

no answer=not cool. 
SO nobody never buy any Opamp from aliexpres its what I conclude????

if I ask this its because I don't want to pay 10$ shipping for a 3$ Opamp.


----------



## rikk009

I have never received an opamp I order from Aliexpress so can't say. Btw, ebay is good alternative for cheap opamps.


----------



## ScottFW

Nymphonomaniac said:


> SO nobody never buy any Opamp from aliexpres its what I conclude????


I've never bought opamps from aliexpress or from any other source shipping from China.
If it's a low price on an ordinarily expensive "audiophile approved" opamp (OPA627... cough cough) it's a fake, whether it's coming from China or elsewhere. Not that price is the only indicator (fakes can be priced high too). 
There are plenty of really good opamps in current production and priced low enough that I just order from Mouser or Digikey or Newark or Allied and have no worries about counterfeit goods.
Ebay might be okay for current production inexpensive opamps if you just need somebody to sell you 1 or 2 without charging $7.95 for shipping. I have purchased a couple of discontinued opamps on ebay, but they were a quad channel version of a not-popular opamp, so not rampantly faked.
Usually if there's a new opamp I want to try, I add it to my running parts list on Mouser and submit the order once I have $100-200 worth of stuff I need for a larger project, so the postage doesn't bother me.


----------



## NymPHONOmaniac (Dec 15, 2017)

ScottFW said:


> I've never bought opamps from aliexpress or from any other source shipping from China.
> If it's a low price on an ordinarily expensive "audiophile approved" opamp (OPA627... cough cough) it's a fake, whether it's coming from China or elsewhere. Not that price is the only indicator (fakes can be priced high too).
> There are plenty of really good opamps in current production and priced low enough that I just order from Mouser or Digikey or Newark or Allied and have no worries about counterfeit goods.
> Ebay might be okay for current production inexpensive opamps if you just need somebody to sell you 1 or 2 without charging $7.95 for shipping. I have purchased a couple of discontinued opamps on ebay, but they were a quad channel version of a not-popular opamp, so not rampantly faked.
> Usually if there's a new opamp I want to try, I add it to my running parts list on Mouser and submit the order once I have $100-200 worth of stuff I need for a larger project, so the postage doesn't bother me.



Okay interesting....thanks for feedback, but I don't think I can buy 100-200$ of audio part. Just wanna begin some swapping. I read lot of feedbakc there...very strange. Look like even if its fake it sound good cause I was looking for Muse8920 wich is priced around 6$ from a seller that got 96positive reviews about it, but i find ONE that say its fake and have a proof:
	

	
	
		
		

		
		
	


	



https://www.aliexpress.com/item/Fre...2466e173&transAbTest=ae803_5&rmStoreLevelAB=0

Now i'm very confuse. 96 feedback say its good, some with pics and it look legit comments. My question is now: can what mean the number under Muses 8920? Because this other seller that look more serious have not G05 but G03 under.....and it cost 15$ instead of 6$.
https://www.aliexpress.com/item/2PC...2466e173&transAbTest=ae803_5&rmStoreLevelAB=0

Anyway, can you kindly suggest me low priced great OPamp, better than the NS5532P??? My obsession about ali is not really about lower priced OPamp but more about free shipping.

Thanks and sorry if I look clumsy....just a OPbeginner here.


EDIT: to make me more confuse, official site show this picture, so now its F07 under model number.


----------



## raoultrifan

O can only suggest authorised dealers (check NJM's webpage). Perhaps Profusion, Mouser, Digikey could be the chosen one for purchasing MUSES opamps.

You could probably replace 5532 with something similar from NJM/JRC or ST (https://www.njr.com/semicon/PDF/NJM2114_E.pdf or even http://www.njr.com/semicon/PDF/NJM5532C_E.pdf).


----------



## raoultrifan (Dec 15, 2017)

I believe you're having http://www.ti.com/lit/ds/symlink/ne5532.pdf.

A cheap upgrade could be http://www.njr.com/semicon/products/NJM5532C.html or https://www.njr.com/semicon/PDF/NJM2114_E.pdf, but also similar opamps from ST should do, just need to compare the specs (usually noise, but sometimes speed/MHz could help).

L.E.: Sorry for double-post, but I was unable to see my post after clicking the Post Reply button.


----------



## olymind1

Rroff said:


> LM4562 though clear and detailed is very "clinical" and in my experience a bit susceptible to power supply noise making it "metallic" sounding - as mentioned earlier in this thread you can do wonders with it sometimes bridging the rails with a 10uf aluminium electrolytic capacitor like an Elna Silmic II or Nichicon FG or KZ - though potentially that is trading accuracy for a subjectively more pleasing sound. That likely depends a bit at what stage in the pipeline it is used and how.


How many volts does it have to be? 16 or 35 ?

These sockets are usable for mounting? https://www.ebay.com/itm/7p-8-PIN-G...hash=item5ae2354103:m:m2tDkkrRS2SYwQfU4BAvyuQ ?




Rroff said:


> I'm actually quite a big fan of the OPA2228 over the 2134 but its only stable at higher gains* so would need intimate knowledge of the circuit *it was going into and quite fussy about the capacitors around it i.e. if there are ones used to limit bandwidth in the feedback loop, etc. and so on to sound good - a lot of people end up with a "grungy" sound because it can't just be dropped into the circuit they are using.


That i don't have.



raoultrifan said:


> *LME49990MA*, besides that is single and needs very good quality PCB to adapters, it could oscillate with ease, so depending on how it's built your Auzentech could be needed additional decoupling caps (fast multilayer 0.01-0.1uF + 1uF tantalum should probably do).


So if i understand correctly do high bandwidth gain op amps need more attention / more stabilizer components when placed into medium / low GBP designs, or can oscillate? Then same thing can be said to AD787BRZ too. So it is probably safer or rather it's simpler to search for a low/medium GBP opamps.

If i decide to buy the 49990s then exactly what kind of additional components do i need to buy for them so they can be stable?


----------



## Rroff

olymind1 said:


> How many volts does it have to be? 16 or 35 ?
> 
> These sockets are usable for mounting? https://www.ebay.com/itm/7p-8-PIN-G...hash=item5ae2354103:m:m2tDkkrRS2SYwQfU4BAvyuQ ?



Voltage will depend on the device - typically a PC soundcard has 12V to play with so 16V is likely fine but you never know if they are using something like a charge pump or other DC-DC conversion to like +/- 12V rails, etc. some claim 35V capacitors have the best "linearity" but I've no idea if there is any truth to that - the ones I use most are 35V, 63V and 100V.


----------



## DR650SE

Static electricity killed my 6S.MKII OP AMP 

I was listening to my AK100/UHA. 6S.MKII with Westone W40s while folding laundry. Picked up a towel, and boom, get shocked in my ear through my Westone W40!!

Then the left earbud stops producing sound. I panic as nothing in this rig is all that cheap to replace and I hate change. I try the headphones in my phone they work. Whew, one bullet dodged. Next I try them straight in the AK100. Whew another bullet dodged. Now I hook my phone to the 6S.MKII. No Dice, one ear out. I remember i got a few OP Amps and maybe, just maybe it's the OP AMP and nothing on the board.  I swap the OPA 627AP with something random. Success!

So long story short, no UHA.6S MKII near static!! No more for laundry and that rig. Going solo AK100 for laundry.

Hears what I swapped them out with. It's one OP Amp I had on hand.  Truthfully, I don't know if I can ever even tell the sound difference between OP amps, i'm not sure my ears are that good   Anyhow, any opinions on the new OP Amp vs old OPA 627AP ?


----------



## leeperry

if you got that 627 for cheap from China then it was fake to begin with ^^


----------



## DR650SE (Jan 15, 2018)

I believe it came from Leckerton Audio when the previous owner owned the amp. It's one of the sets that came with the amp when I bought it used.

However I coul be wrong since it came with the amp to me. Who knows where it came from. Doubtful I could tell any difference between real and fake either way.


----------



## imran27

So in my XD-05 I have tried following opamps:
- OPA1612
- OPA1602
- OPA1652
- LME49720
- Burson V5i-D

Of all these, LME49720 and OPA1652 are my favourites. LME49720 is just amazing, but compared to OPA1652 it has a laid back recessed mid-range, soundstage isn't as immersive and forward. Overall sound of LME49720 is somewhat lean as in lean and quick. Very detailed and transparent though and sounds very very real. But the soundstage presentation is more laid back like as if you're standing on the stage with instruments towards left, right and behind kinda like you are a performer/singer. OPA1652 gives you a more spectator kind of soundstage presentation. Everything seems to come from forward and with adequate body and thickness. It is still detailed but not at the level of LME49720.

For me, I prefer LME49720 for everything except videos and gaming. For videos, gaming or generally anything demanding a forward presentation I go to OPA1652.

In a couple of weeks I will also be receiving and testing these:
- OPA1642
- OPA1692 (In Preview, more than a month of lead time)
- OPA2140
- OPA2189 (In Preview, single version is Active)
- OPA2227
- ADA4610-2

And other suggestions you people might have


----------



## rikk009

imran27 said:


> So in my XD-05 I have tried following opamps:
> - OPA1612
> - OPA1602
> - OPA1652
> ...


What would you say about the Burson?


----------



## imran27

rikk009 said:


> What would you say about the Burson?


The V5i-D is pretty good all rounder. The highlight of that opamp is the soundstage, pretty expansive and imaging also is top notch. Detail retrieval is good enough. Bass and treble extensions are just about present ie you can't call it deep but not shallow either, same goes for treble.

The soundstage render/presentation is like as if the playback is happening in front of you in a closed well sealed studio. There is a lack of airiness though.

Everything sounds natural. But this natural is different from the realistic natural rendering of LME49720. Instruments in a studio sound slightly different than in an opera hall. V5i-D produces that studio'ish natural timbre whereas LME49720 produces the opera hall/open field kind of timbre/feel.

Basically V5i-D I feel is like a technically superior version of OPA1652 (details, clarity, soundstage characteristics).


----------



## raoultrifan

rikk009 said:


> What would you say about the Burson?



There's also an entire thread about BURSON opamps, in case you might be interested I could share some thoughts too:
https://www.head-fi.org/threads/bur...ssion-and-reviews.854912/page-9#post-13830420
https://www.head-fi.org/threads/bur...sion-and-reviews.854912/page-10#post-13970143

Personally I'm thrilled about the SS V6 Classic.


----------



## rikk009

raoultrifan said:


> There's also an entire thread about BURSON opamps, in case you might be interested I could share some thoughts too:
> https://www.head-fi.org/threads/bur...ssion-and-reviews.854912/page-9#post-13830420
> https://www.head-fi.org/threads/bur...sion-and-reviews.854912/page-10#post-13970143
> 
> Personally I'm thrilled about the SS V6 Classic.


I know, I was just asking his preference. Thanks.


----------



## Rroff

imran27 said:


> In a couple of weeks I will also be receiving and testing these:
> - OPA1642
> - OPA1692 (In Preview, more than a month of lead time)
> - OPA2140
> ...



2140 in my testing had a slightly "off" colouration to the sound for want of a better way to put it - though I did have some issues with my amp due to the number of op amps I'd swapped out had weakened a connection by the time I got to the 2140. I found it very similar to the AD8066 in that it seems to preserve directionality down to lower frequencies giving a distinctive bass generally quite a dark sound but I had some issues in the treble (occasionally heard some "mushiness") with it which I've not gone back to retest to see if it was due to the connection issue. Think I need to clear a weekend build another basic amp without any of the frills of the amps I have in use now and retest some of these op amps.

I quite like the 2227 but IMO the 2228 is better if you can make it work.


----------



## DRKreiger

I am curios of peoples experiences with the LME49720NA. I am about to replace the JRC4580's in my HT Claro Halo Sound card.

Has anyone proven the severity of the oscillation issue with out decoupling capacitors present?


----------



## imran27

DRKreiger said:


> I am curios of peoples experiences with the LME49720NA. I am about to replace the JRC4580's in my HT Claro Halo Sound card.
> 
> Has anyone proven the severity of the oscillation issue with out decoupling capacitors present?


I love it.

It is pretty transparent and neutral. Overall it's a very lean sounding opamp best suited for reference and analytical listening. It is very accurate in it's reproduction of instruments and the imaging is pretty darn precise. It lacks soundstage though, not very good at it and what it has is also quite laid back.

Whatever opamp I use is only for a short stint because I keep coming back to LME49720.


----------



## DRKreiger

That's good. Transparent and accurate is what i am after. The preamp will handle the soundstage quite well. I need a clear, and very undistorted signal. 

Running this Sound card to a 6AK5/5654W preamp, and then to a converted Conn 12ax7 and 7868 Organ amp. 

Thank's for the input.  Did you add decoupling caps to the circuit?  I am a bit concerned that I will need to improve on the power conditioning on the TH Omega card.


----------



## imran27

DRKreiger said:


> That's good. Transparent and accurate is what i am after. The preamp will handle the soundstage quite well. I need a clear, and very undistorted signal.
> 
> Running this Sound card to a 6AK5/5654W preamp, and then to a converted Conn 12ax7 and 7868 Organ amp.
> 
> Thank's for the input.  Did you add decoupling caps to the circuit?  I am a bit concerned that I will need to improve on the power conditioning on the TH Omega card.


LME49720 is very sensitive to RFI. You will need good shielding.
On my XD-05, decoupling provided no change. Neither better nor worse, no change at all. I guess it's because it is very well bypassed in the circuit itself, any more decoupling is sort of redundant in my case.

Do note though, LME isn't good at layering the sounds properly. Subtle tone variations often go unnoticed. You may want OPA1612 or Burson V5i-D for that purpose. Those 2 are also pretty good opamps.


----------



## rikk009

My experience with LME49720 and LME49990 was....Former one sounds more laidback and musical and later one more punchy bass and dynamics. So I use 990 for fast music and 720 for everything else. Mind you I am comparing 720(single) vs 990(dual on an adaptor) in Mstage HPA-1.


----------



## Rroff (Jan 24, 2018)

DRKreiger said:


> That's good. Transparent and accurate is what i am after. The preamp will handle the soundstage quite well. I need a clear, and very undistorted signal.
> 
> Running this Sound card to a 6AK5/5654W preamp, and then to a converted Conn 12ax7 and 7868 Organ amp.
> 
> Thank's for the input.  Did you add decoupling caps to the circuit?  I am a bit concerned that I will need to improve on the power conditioning on the TH Omega card.



I've no experience of the JRC4580 but I've used TI's version the RC4580 a fair bit and its pretty decent if you are looking for accurate, neutral and largely transparent sound so I suspect the JRC is the same - like many that are largely transparent it is a bit "raw" sounding and lacks the "musicality" of some other op amps but for reference use its pretty close to ideal. (Along similar lines if you are using current hungry headphones the NJM4556A is pretty good where you value accuracy and transparency but personally I don't rate it with high impedance, less current demanding headphones like the Sennheiser HD600 series where I've heard it struggle at times and again is a bit "raw" sounding).

The LME49720 comes across as a bit clearer and a bit crisper sounding but that is partly because it also seems a touch "lean" as someone else noted - I've found all of that line up seem very sensitive to power supply noise and RFI if you want distortion free as well (The LM4562 very easily starts to sound a bit metallic with power supply noise and is often greatly enhanced with extra decoupling capacitors in my experience though I've never scoped it, etc. for hard data - I've only a fairly basic oscilloscope and most of my limited training in using one is for electronics in general and not so much audio engineering).

The OPA1612 is a pretty excellent op amp that I've never noticed struggling for articulation, etc. but its a touch light in the bass a touch bright towards the upper end and seems to takes a good bit of use before it loses a bit of a "synthetic" kind of colouration to the sound - I've never really been much of a believer in "burn in" with op amps but this one definitely takes awhile before the sound becomes more natural and it isn't just me getting used to it as I've a few dozen of them and its very noticeable when picking out a new one that I've not used before - one of my most used headphone amps is a reworking of the O2 I did for USB power using the OPA1612 for gain and LMH6643 for buffers and its immediately noticeable if I change the OPA1612 out - personally I highly rate it as an op amp for audio but for reference use it close but not perfect. If you aren't 100% looking for reference but want accurate and transparent but with a good musical "signature sound" then one of the OPA16xx line like the OPA1612 would probably be ideal.


----------



## DRKreiger

OK.. thank you, great info. I am looking at the OPA1612, and it seems only a surface mount is available. Would this require an adapter to  fit into the DIP8 socket on my card? I am seeing some already mounted to adapter ones available, and pricing is not too bad.


----------



## Rroff

Yeah requires an adaptor unfortunately - at least I've never seen them available in DIP format - most of the OPA16xx series is either SOIC or stuff like VSON which is even worse for DIYing heh.


----------



## DRKreiger

So this would be the easiest option then for that solution?
https://www.ebay.com/itm/1PCS-TI-OP...770539?hash=item33dae4f6ab:g:LWMAAOSwUchaB6-h


----------



## DRKreiger (Jan 24, 2018)

Alright.. So the LME 49720's are all in the card. Running some music to get a bit of current through them before i analytically listen. But they are definitely a wider soundstage than the JRC 4580's. The mids are a bit fuller, and tighter bass. The biggest thing i can attest to is the clearer 5k and above.


----------



## Rroff

DRKreiger said:


> So this would be the easiest option then for that solution?
> https://www.ebay.com/itm/1PCS-TI-OP...770539?hash=item33dae4f6ab:g:LWMAAOSwUchaB6-h



Assuming its the genuine op amp then yeah that would make it easier - if you've got a reasonably precise soldering iron, some flux designed for soldering ICs (helps to hold the IC in place and reduces chance of accidentally bridging connections) and some moderate soldering experience its pretty easy to mount them on an adaptor yourself and the adaptors can be bought really cheap.


----------



## raoultrifan

I have a bunch of ST4580 in my Mackie MR6mk3 active speakers (about 6 x ST4580 per speaker), sound is very good actually...everything sounds neutral. I like most that despite such an opamp is being used, noise is very well kept under control: unless I'm placing my ear 10" in front of the tweeter I can't hear any noise (and this test was done at 1 AM when a single fly could sound really noisy).

Under most circumstances opamps should not sound different, unless there are "visible" differences in their datasheet. Although, we all know that opamps may sound different because:
- They have different CMRR/PSRR figures and the PSU from the circuit may be noisy or having high ripple, then the opamp having a better CMRR/PSRR will sound less grainy and with better details and transients.
- FET/JFET-input may sound different than BJT-input opamps (it may worth reading OPA604 datasheet regarding odd/even harmonics).
-  Different noise specs will make a difference, especially if used in Voltage Gain (pre-amplification), but also in Low Pass Filter of a DAC.
- The circuit around the opamps may be configured for some opamps only (usually related to opamp decoupling, but also input or output impedance match with the circuit in front or after the opamp.
- Some opamps may oscillate and sometimes the addition of many undesired harmonics may sound better to some ears.


----------



## imran27

raoultrifan said:


> I have a bunch of ST4580 in my Mackie MR6mk3 active speakers (about 6 x ST4580 per speaker), sound is very good actually...everything sounds neutral. I like most that despite such an opamp is being used, noise is very well kept under control: unless I'm placing my ear 10" in front of the tweeter I can't hear any noise (and this test was done at 1 AM when a single fly could sound really noisy).
> 
> Under most circumstances opamps should not sound different, unless there are "visible" differences in their datasheet. Although, we all know that opamps may sound different because:
> - They have different CMRR/PSRR figures and the PSU from the circuit may be noisy or having high ripple, then the opamp having a better CMRR/PSRR will sound less grainy and with better details and transients.
> ...


Add to that:
- Input capacitance
- Open loop gain effects
- Phase response
- Input current/voltage noise density
- Output impedance over spectrum
- EMI/RFI sensitivity


----------



## raoultrifan

Well, most are already included in the "datasheet differences". 

Again: a circuit is usually created across a dedicated opamp, so usually a possible upgrade should be done with an opamp having similar specs (but better CMRR/PSRR and lower noise and THD), at least in regard with "input bias current", "offset voltage", "output impedance". 

've noticed myself improvement in LPF stage when swapping LME49860 with MUSES8820, but never noticed any differences when swapping LM4562 with LME49720 or vice-versa, mostly because these opamps are internally sharing an identical schematic.

I've also noticed improvement in I/V when using MUSES8920 and MUSES01 against NE5532 or LME49720, but never noticed any difference if swapping LME49702 with LM4562.


----------



## imran27

raoultrifan said:


> Well, most are already included in the "datasheet differences".
> 
> Again: a circuit is usually created across a dedicated opamp, so usually a possible upgrade should be done with an opamp having similar specs (but better CMRR/PSRR and lower noise and THD), at least in regard with "input bias current", "offset voltage", "output impedance".
> 
> ...


LM4562, LME49720 and LME49860 are basically the same opamp.
LME49720 is LM4562 with a better manufacturing.
LME49860 is LME49720 with higher power supply range.


----------



## DRKreiger

A ton of good info to research.  

I think I may add decoupling caps to the 49720. Oscillation can h have pretty pronounced impact on a tube amp. I had a zobel (RD Network) across the primary side on my output transformer fail. That was very noticeable. We shall see how these perform,  then think of decoupling
Improvement. 

I have a few .47uf caps I can donate to the experiment.  2 in parallel should be enough.


----------



## imran27

DRKreiger said:


> A ton of good info to research.
> 
> I think I may add decoupling caps to the 49720. Oscillation can h have pretty pronounced impact on a tube amp. I had a zobel (RD Network) across the primary side on my output transformer fail. That was very noticeable. We shall see how these perform,  then think of decoupling
> Improvement.
> ...


I tried the panasonic 82uF/35V, 20% tolerance caps on my opamps, especially the LME, didn't make any difference.
\\\


----------



## raoultrifan

imran27 said:


> LM4562, LME49720 and LME49860 are basically the same opamp.
> LME49720 is LM4562 with a better manufacturing.
> LME49860 is LME49720 with higher power supply range.



Although in my tests LME49860 it's way much noisier than LME49720 & LM4562...have no idea why. Had it tested in Voltage Amplification stage, but also in LPF (test done with LME49720 for left channel and LME49860 for right channel and noise coming from the  left channel was half of the noise coming from the right).

It's like same TV brand and model, but if "Made in Japan" then it's better than "Made elsewhere".


----------



## DRKreiger

That seems a bit high on the values. .1-10uF I thought was the desired spec.

What application? What do you run these in? I am going to run some leads to my OPamp and test the voltages to see how the HT omega power supply holds up under load. 

I always use the Dubilier 15-16 series caps for coupling/decoupling, or oscillation suppression.


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## Rroff (Jan 25, 2018)

For most cases yeah you want (depending on type of cap, etc.) in the region of .1 to 10uf with these op amps - others might vary I dunno but most I've looked at recommend in the datasheet 10uf for aluminium electrolytics when using those - I swear by Nichicon KZ for clean neutral sound. Elna Silmic Ii are nice but they definitely aren't neutral not even close - quite pleasing though to listen to. The other option I use a bit is the Nichicon FG but they seem to boost somewhere in the 100s of Hz region (not enough of an expert to narrow it down) giving a bit more of a "full" or even warmer sound.

I also highly rate Cornell Dubilier caps if you are looking for a reference sound - some of them are a touch lean on the bass but otherwise excellently neutral through most of the frequency range - though I'm talking here more about film caps that are in the audio signal path, etc. but where appropriate mostly holds up for decoupling, etc. as well.

EDIT: Disclaimer this is all my subjective opinion based on 100s of hours of playing around as a hobby - I'm certainly not qualified in this field (dropped out of electronics engineering to go into computing) and what I experience might be very different for anyone else.

EDIT2: For the LME range and LM4562 that are closely related I found best results came from having some 0.01-0.1uf ceramic or similar caps from the rails to ground near the op amp itself and then a rail to rail 10uf aluminium electrolytic also close - adding extra 10uf AE caps from rail to ground alongside the high speed caps didn't seem to make any difference at all - I've not experimented with a range of values to see if something smaller like 2uf would have any effect.

Using say a 0.1-0.22uf film cap rail to rail in place of the 10uf AE seems to make some people happy but personally I found it narrowed the soundstage somehow - not sure how - other people seem happy with the results of it though.


----------



## imran27

Just a crazy question: Does a 3% silver lead free solder give better extension in highs and airier wider soundstage? Does it also make the sounds a bit dry?

I notice that the new batch of opamps that I soldered with silver contaminated solder all have these characteristics. But the older ones which used a normal lead free solder don't have this characteristic.

It could be the opamps themselves but I highly doubt.

Opamps used: OPA2209, OPA2192, OPA2197, OPA1662


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## Rroff (Jan 28, 2018)

Possible it is a non-eutectic solder and your setup/technique resulted in poorly set solder joints - in extreme cases it might cause the op amp to oscillate which can manifest as a brighter, airier sound but that isn't a good thing :s that would be a fairly unusual occurrence though.

I've used a good range of eutectic solders from rubbishy cheap general purpose noname stuff from the Amazon through to more expensive blends and as long as the joint is properly formed I've never heard a noticeable difference. Though if its really cheap and dirty stuff it probably doesn't help the noise floor.


----------



## afshin (Feb 1, 2018)

Yes ... Certainly tin and soldering are very important and influential
Tin can affect the wide frequency and dynamic .


----------



## Bluess

Hi guys, I want to share my experience 
My initial impression running with LME49600 is it has great micro details and air compare to muses02, vocal feels much lighter compare to muses02.
Nothing is harsh even with some track prone to hissing.
Running with BUF634 you get much thicker and sweeter mid but you loses the great micro details and air.
I don't like it as much as muses02 because I listen li it the most ever since I bought a Fiio E12DIY.
But after giving it a few hours, I like it much more now. Let see how it goes after a few days.
So
 , how is muses03 compare to muses02 and sparkoss ss3602? Is it worth the upgrade?


----------



## KingFiercer

Hi guys. I want to try replace OPA2134PA in my HP-A4BL with one of higher quality. Is OPA1642 a good choice for this?


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## imran27 (Feb 11, 2018)

KingFiercer said:


> Hi guys. I want to try replace OPA2134PA in my HP-A4BL with one of higher quality. Is OPA1642 a good choice for this?


I highly recommend OPA2209 or OPA2192. OPA2192 being my favorite CMOS opamp and OPA2209 my favorite bipolar alongside OPA1612.

2209 has particularly an amazing resolution and detail level with a Great deal of soundstage depth. It is very airy, the bass and treble regions extension pretty well and overall it has a very neutral lively tonality. It doesn't sound dry and lifeless like say LME49720 but very alive and resolving. It particularly has the best treble detail and clarity I've heard, the best timbre in mid range. The vocals sound just so real, they have a very realistic feeling to it. Instruments sound perfect in their tone, nothing emphasized but everything is so well presented.

Forgot to say, it has the most textured sound I've heard.

Tried in xDuoo XD-05 and Burson Play I/V stage


----------



## Rroff (Feb 13, 2018)

Hmm haven't played with the 2209 before that I can recall - don't have any in my collection right now either - gonna order a couple to try out.

EDIT: Anyone know much about these op amps - the 2209 seems to be grouped on TI's pages with the 2211 (which I do have) for some reason - the 2211 IIRC just being a laser trimmed 1612 and largely indistinguishable to listen to though maybe a touch more spacious sounding - its hard to be sure as both, but especially the 1612, seem to do a little bit of "burn in" over the first few dozen hours of use.


----------



## endia

imran27 said:


> I highly recommend OPA2209 or OPA2192. OPA2192 being my favorite CMOS opamp and OPA2209 my favorite bipolar alongside OPA1612.
> 
> 2209 has particularly an amazing resolution and detail level with a Great deal of soundstage depth. It is very airy, the bass and treble regions extension pretty well and overall it has a very neutral lively tonality. It doesn't sound dry and lifeless like say LME49720 but very alive and resolving. It particularly has the best treble detail and clarity I've heard, the best timbre in mid range. The vocals sound just so real, they have a very realistic feeling to it. Instruments sound perfect in their tone, nothing emphasized but everything is so well presented.
> 
> ...




i too want to try it in my zishan dsd player's i/v stage but i'm not sure if it is suitable in place of op275,
the stock i/v opamp is op275 but  it's architecture is butler (bipolar and jfet at the same time),

so should i choose bipolar or jfet or am i free to try whatever it is?

also, there is an improved version from AD, ADA4075-2 claimed that much lower noise and lower offset, anyone experienced it?

thanks in advance..


----------



## imran27

endia said:


> i too want to try it in my zishan dsd player's i/v stage but i'm not sure if it is suitable in place of op275,
> the stock i/v opamp is op275 but  it's architecture is butler (bipolar and jfet at the same time),
> 
> so should i choose bipolar or jfet or am i free to try whatever it is?
> ...


You'll benefit from a CMOS opamp which has a low differential input capacitance (less than 5 pF).
Bipolars with low voltage and current noise density are good options.

Open loop gain (and CMRR) makes a great deal of difference.

The lack of PSRR can be easily mitigated by adding bypass caps but Aol and CMRR can't be compensated for externally.


----------



## endia

imran27 said:


> You'll benefit from a CMOS opamp which has a low differential input capacitance (less than 5 pF).
> Bipolars with low voltage and current noise density are good options.
> 
> Open loop gain (and CMRR) makes a great deal of difference.
> ...



wow, thanks a lot for so quick reply..

i have opa1688, i can try it..
but do you suggest your favorite OPA2192 over it?


----------



## SpudHarris

I have been away from the forums for a looooong time. Mostly been happy with my set up based around the Oppo HA1 and given up on portable rolling since getting the NW-ZX2... However, I've recently been playing with the Lycan amp and have to say I've enjoyed the Opamp tweaking again.

Anyhoo, don't want to derail the thread but just wanted to say that the OPA602BP is at present my absolute favourite. I gave all my OPA1612's away when I sold my balanced PB1 so have just ordered again from Farnell. Any love for either of these or is there any newer Opamps I should be auditioning?


----------



## imran27

SpudHarris said:


> I have been away from the forums for a looooong time. Mostly been happy with my set up based around the Oppo HA1 and given up on portable rolling since getting the NW-ZX2... However, I've recently been playing with the Lycan amp and have to say I've enjoyed the Opamp tweaking again.
> 
> Anyhoo, don't want to derail the thread but just wanted to say that the OPA602BP is at present my absolute favourite. I gave all my OPA1612's away when I sold my balanced PB1 so have just ordered again from Farnell. Any love for either of these or is there any newer Opamps I should be auditioning?


OPA1612 vs OPA602BP?


----------



## raoultrifan

Thanks for sharing SpudHarris!

By looking to the specs (especially speed, unity gain stable and input bias current) I can see that OPA602 could be a good candidate to I/V stage of a DAC, though it's noise is a bit higher than OPA604, way above the noise of the OPA8597 and above the AD797. It's speed is not very high, so it will probably not oscillate in most configurations, even with a badly designed PCB.

In what stages have you been using it, please? I/V? LowPass? Voltage Gain? Output buffer?

Thank you!


----------



## SpudHarris (Feb 24, 2018)

What do you mean? Are they not both considered good?

Sorry, this was in response to reply from imran27


----------



## SpudHarris

raoultrifan said:


> Thanks for sharing SpudHarris!
> 
> By looking to the specs (especially speed, unity gain stable and input bias current) I can see that OPA602 could be a good candidate to I/V stage of a DAC, though it's noise is a bit higher than OPA604, way above the noise of the OPA8597 and above the AD797. It's speed is not very high, so it will probably not oscillate in most configurations, even with a badly designed PCB.
> 
> ...



Hi raoultrifan,  thanks for the reply, I have only been testing on the Lycan of late but ideally I will be also using in my Fi-Quest. Really I just wondered if there are any new Opamps worth trying.


----------



## imran27

SpudHarris said:


> What do you mean? Are they not both considered good?
> 
> Sorry, this was in response to reply from imran27


I don't know anything about OPA602BP. I want to know how does it compare to OPA1612?

As of now my favorite is the OPA2209


----------



## SpudHarris

Opa602BP is a great Opamp. The TO99 version is very rare (Opa602CM). I'm sure Leeperry will chip in regarding these. I think he hooked me up with a seller about 5 years ago of the TO99 version. Managed to grab a couple plus a spare.

This is my go to at present but can't compare against 1612 until they arrive. Like I said, I seem to have got rid of my1612's by including them in portable amp sales.


----------



## raoultrifan

SpudHarris said:


> [...] Really I just wondered if there are any new Opamps worth trying.



Hi! Define new. 
AFAIK the OPA1688 is kinda a new, but really new would be SS V6 from Burson and MUSES03 from NJM/JRC. The first one was already tested with success in CMoy and also in Obejctive2, the second was tested in many devices and the last one should be very good in I/V stages (not sure who tested yet, sorry).


----------



## imran27

SpudHarris said:


> Hi raoultrifan,  thanks for the reply, I have only been testing on the Lycan of late but ideally I will be also using in my Fi-Quest. Really I just wondered if there are any new Opamps worth trying.


OPA1692, OPA2189.

I've pre-ordered my OPA1692 and eagerly waiting for OPA2189 to go into production. The single version OPA189 is already at my desk, just waiting for adaptors.


----------



## SpudHarris

Farnell has OPA189 as a dual Opamp... Will buy a few anyway!


----------



## SpudHarris

Muses 8832? Anyone tried?

Have got OPA2209, OPA189 and OPA1612 on order will report back when I've tried them.


----------



## raoultrifan

Don’t have any devices to test 8832, also needs to be soldered on the PCB. It’s a low-voltage opamp (up to 14V), so it’s mostly for USB powered devices, although seems to have very good specs.


----------



## endia (Feb 27, 2018)

raoultrifan said:


> Don’t have any devices to test 8832, also needs to be soldered on the PCB. It’s a low-voltage opamp (up to 14V), so it’s mostly for USB powered devices, although seems to have very good specs.



is that "1V/µs" slew rate enough?


----------



## raoultrifan (Feb 27, 2018)

It should be fine, I tend to trust Japanese companies usually. 

http://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php

L.E.: 8832 is designed for low-power devices (probably USB-based power), that means that ouptut RMS is somewhere around 1.3V, hence peak-to-peak should be around 3V.


----------



## Rroff (Feb 27, 2018)

endia said:


> is that "1V/µs" slew rate enough?



Personally I'd say no - several well regarded sources recommend at least ~1.7V/µs for audio or that 1V/µs is "plenty" for audio but that assumes its bang on when quite a lot of op amps it is actually the "typical" rating (including most NJM/JRC devices) and can drop down significantly below.

An old school audio and electronics engineer I know IRL when I brought the subject up was pretty adamant you "should" aim for 10V/µs with audio heh though he is used to working with like 1970s or earlier electronics which might change the game a bit (he isn't a big fan of op amps over discretes either for audio).

Back on topic a bit - nwavguy makes a case for 1V/µs to justify use of the 4556 and while I've not noticed it with lower impedance, high current headphones with some high impedance headphones that don't take a lot of power I've noticed some minor issues with articulation which while I can't prove it I'm like 99% sure are down to the slew rate - when I drop in a couple of RC4580 or LMH6643 (low voltage part so don't drop it into a +/- 12V amp, etc.) I don't notice it. (One tune I use for testing is Swedish House Mafia - One which has a number of instruments used which are close to pure wave forms).

End of the day it is more my subjective impression than something backed up with science but I've always found better results using op amps that can do 5-10V/µs (there is no real benefit for shooting for the stars with slew rates and it isn't uncommon with op amps designed for things like ADSL drivers that the slew rates come from the use of "boosting" systems that don't always produce the best results for audio).

EDIT: This is what Doug Self has to say in this context (while talking about an op amp with a slew of 9V/µs):



> Assume you are running your op-amp from±18V rails, and that it can give a±17V swing on its output. For most op-amps this is distinctly optimistic, but never mind. To produce a full-amplitude 20 kHz sine wave you only need 2.1 V/µs, so even in the worst case there is a safety margin of at least four times. Such signals do not of course occur in actual use, as opposed to testing. More information on slew limiting is given in the section on op-amp distortion.


----------



## endia (Feb 27, 2018)

Rroff said:


> Personally I'd say no - several well regarded sources recommend at least ~1.7V/µs for audio or that 1V/µs is "plenty" for audio but that assumes its bang on when quite a lot of op amps it is actually the "typical" rating (including most NJM/JRC devices) and can drop down significantly below.
> 
> An old school audio and electronics engineer I know IRL when I brought the subject up was pretty adamant you "should" aim for 10V/µs with audio heh though he is used to working with like 1970s or earlier electronics which might change the game a bit (he isn't a big fan of op amps over discretes either for audio).
> 
> ...



that is why I asked..
just checked nwavguy's site, he is referring Doug Self and his claim is 3 V/µs is "fast enough" for many audio applications although @raoultrifan's "scenario" needs less than 0.5 V/µs at a frequency of 25kHz in calculation (http://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php)..


----------



## Rroff (Feb 27, 2018)

endia said:


> that is why I asked..
> just checked nwavguy's site, he is referring Doug Self and his claim is 3 V/µs is "fast enough" for many audio applications although @raoultrifan's "scenario" needs less than 0.5 V/µs at a frequency of 25kHz in calculation (http://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php)..



Fair enough if you've a ~3V peak from something more designed for USB application then in theory you barely need 1V/µs - but that won't get the best out of some headphones and even then I'm not entirely convinced. Plugging the kind of numbers from my variation of the O2 comes at around 1.5V/µs.

Dunno I'm not an engineer but 100s of hours of messing about with DIY amps doesn't leave me with the impression lower slew rates are ideal.

EDIT: One thing to bare in mind as well is that a lot of my impressions come from using the Sennheiser HD600 which seem to be a fan of all things voltage.


----------



## imran27

Considering +/-15V rails and assuming opamp can make it to 15V output it turns out 4.7V/us is the minimum.

Also, once it's above 5V/uS it doesn't change anything.

opa2209 which is 6m4V/uS is better than many other opamps with 22 or even 27V/us slew rate.


----------



## SpudHarris

Got OPA2209, 1612 and 189 today but only got to solder up OPA189's due to work commitments. Listening now and obviously too early to go into detail but have to say that they do sound very "high end". So far (1 hour in) nothing seems lacking...


----------



## imran27

SpudHarris said:


> Got OPA2209, 1612 and 189 today but only got to solder up OPA189's due to work commitments. Listening now and obviously too early to go into detail but have to say that they do sound very "high end". So far (1 hour in) nothing seems lacking...


My Burson Play is left channel dead. Couldn't try a full OPA2209/OPA209 config but even with just 1 OPA2209 in I/V difference is significant.

Btw, OPA189 are about the best specs I've read in an opamp.

And OPA2209 is the best step response I have seen.


----------



## SpudHarris

Well I don't know about the specs I just go with initial recommendations then my own personal listening experiences.  I have to say that a little longer into my listening with the OPA189's I am very impressed. 

For info I am using flac or 24 bit high res into Oppo HA1 then discreet HP output to Burson Lycan then into HD800's.

The OPA189 is a fine sounding OpAmp for sure and certainly worth the money...


----------



## imran27

SpudHarris said:


> Well I don't know about the specs I just go with initial recommendations then my own personal listening experiences.  I have to say that a little longer into my listening with the OPA189's I am very impressed.
> 
> For info I am using flac or 24 bit high res into Oppo HA1 then discreet HP output to Burson Lycan then into HD800's.
> 
> The OPA189 is a fine sounding OpAmp for sure and certainly worth the money...


I am yet to try them and the full set of OPA2209/209.

Thank you much, that gives me a lot more confidence on OPA189.

I guess you will like OPA2209/OPA209 too. Please keep us posted on your impressions.


----------



## Rroff (Feb 28, 2018)

imran27 said:


> Considering +/-15V rails and assuming opamp can make it to 15V output it turns out 4.7V/us is the minimum.
> 
> Also, once it's above 5V/uS it doesn't change anything.
> 
> opa2209 which is 6m4V/uS is better than many other opamps with 22 or even 27V/us slew rate.



Yeah for audio rarely does going for very high slew rates make any difference once you hit a certain point and can even be a detriment for audio if it makes the op amp more complex to get stable operation and/or uses some crude method of boosting slew rates - 6.4 should be more than enough for almost any useful scenario.

Still haven't got to try the 2209 - local place has it but its a bit cheaper from elsewhere who also have some other bits I want but waiting until current weather to clear before I order as otherwise parcel will just end up delayed and a higher chance of lost :s

2209 looks pretty decent for audio in the datasheet - its a bit behind the OPA16xx series in some areas but not by so much that would make any significant difference for audio while having a better balance of parameters elsewhere which should make for a nicely rounded op amp on paper performance wise - if they'd just got the output able to supply around 70ma or ideally a bit closer to 100ma and the options of DIP format as well it would wipe the floor if it sounds as good as people say.


----------



## SpudHarris

Well, had another evening with the OPA189... 

I'm sure I'll get to the others at some point but I'm not in a rush to be truthful... Just ordered a few more for my Fi-quest.


----------



## imran27

Rroff said:


> Yeah for audio rarely does going for very high slew rates make any difference once you hit a certain point and can even be a detriment for audio if it makes the op amp more complex to get stable operation and/or uses some crude method of boosting slew rates - 6.4 should be more than enough for almost any useful scenario.
> 
> Still haven't got to try the 2209 - local place has it but its a bit cheaper from elsewhere who also have some other bits I want but waiting until current weather to clear before I order as otherwise parcel will just end up delayed and a higher chance of lost :s
> 
> 2209 looks pretty decent for audio in the datasheet - its a bit behind the OPA16xx series in some areas but not by so much that would make any significant difference for audio while having a better balance of parameters elsewhere which should make for a nicely rounded op amp on paper performance wise - if they'd just got the output able to supply around 70ma or ideally a bit closer to 100ma and the options of DIP format as well it would wipe the floor if it sounds as good as people say.


This is something OPA2209 changed for me drastically. Even with a slew rate of only 6.4 V/us it replaced all the opamps, even the V5i-D. Definitely better than LME49720.

Compared to OPA1612 however it's a toss. It is actually a complementary. OPA2209 is more like a reference kind of sound, very accurate and airy, soundstage is controlled and precise. Soundstage depth is amazing.

OPA1612 otoh has the best sub bass performance I have heard. OPA2209 does reproduce sub bass as deep or deeper than OPA1612 but the latter has a pretty significant presence in the sub bass region. The sub bass regions are more well pronounced with OPA1612. I don't like the highs of OPA1612 though, they sound artificial to me. Another great thing about OPA1612 is the soundstage, huge. Just holographic and engaging. Probably my pic for enjoying the music.

Although, if you are looking out for mid range (mids) and timbre, OPA2192 should be your pick.


----------



## Rroff

imran27 said:


> This is something OPA2209 changed for me drastically. Even with a slew rate of only 6.4 V/us it replaced all the opamps, even the V5i-D. Definitely better than LME49720.
> 
> Compared to OPA1612 however it's a toss. It is actually a complementary. OPA2209 is more like a reference kind of sound, very accurate and airy, soundstage is controlled and precise. Soundstage depth is amazing.
> 
> ...



Given that TI group the 2209 in with the 2211 which I believe is just a 1612 laser trimmed and with some other minor changes for performance in areas where DC is important it wouldn't surprise me if they shared a lot "under the hood". An alternative to the 1612 with more reference like sound would be a great option to have - I've ended up using the 1612 a lot the only op amp that regularly pulls me away really is the AD8066.

I've found the highs of the OPA1612 settle down a bit after a few dozen hours of music through them - I'm generally not a big believer in "burn in" but I can distinctly tell between the 1612s I've had in use for awhile and one pulled new out the box. There is still a bit of a "tropical juice" brightness to the highs though for want of a better way to describe it.


----------



## SpudHarris

Got everything soldered up now so will be testing OPA2209 this evening... Sorry for the poor quality ipad pics.


----------



## SpudHarris

The OPA2209 is very nice indeed. I forgot how much fun rolling can be, especially with a testbench such as the Lycan. Just playing my favourites playlist of songs I know inside and out. Will leave the OPA2209 in for a few days before moving onto OPA1612...


----------



## KingFiercer (Mar 10, 2018)

Tested some opamps in Fostex HP-A4BL.
OPA1642 - Improved clarity, dynamics and soundstaging. But over time, these dynamics and speed become tiresome.
OPA637BP - Sounds full, dense and natural, with interesting "between instruments" soundstaging. Good resolution. But it's a bit bloated near 100Hz. Intimate warmth sound, like good cassette deck. On some tracks it sounds very good.
OPA604AP - Bassier and harsher overall than OPA2134PA. Mids are recessed.
Now waiting OPA2209. I'd like something between OPA637 and OPA1642. However default 2134 is already pretty good and well-balanced - well-defined bass, good forwarded mids and non-fatigue highs.


----------



## SpudHarris

Tested a few different chips yesterday in quite a long session. Pretty much everything left me yearning for the sound OPA2209, I think it is just amazing...


----------



## Rroff

OPA2209 ordered  along with some other stuff.

Might be a little while til I get to test though.


----------



## imran27

SpudHarris said:


> Tested a few different chips yesterday in quite a long session. Pretty much everything left me yearning for the sound OPA2209, I think it is just amazing...


The resolution and soundstage depth is the best part about OPA2209


----------



## Bluess

Hi guys, after a few weeks listening to V5iD, muses02 and SS3602 pairing with LM49600.

My setup: X7II + E12DIY in high gain + Norne Draugh V2C + Denon D7200.

I came to a conclusion as below:

SS3602>V5iD>Muses02

The muses02 to my ear is more mid centric and smoother compare to the other two.

Meanwhile V5iD and SS3602 are much less mid forward, with v5i and ss3602 you will get more depth and width, much better clarity than muses02. The bass get more control with these 2. However the Treble in V5iD does not impress me as much as SS3602.

Out of the 3, mid in ss3602 is the most laid back, i think that's the reason why I feel the air and space is wider?

Anyway, considering the price tag SS3602 performs as expected. Meanwhile the V5iD is a surprise for me, it's half the price tag of SS3602 but the differences in performance is not that far off. I find them sounding quite similar, I think I can say SS3602 is an upgrade version of V5iD with twice the price tag.


----------



## martist

Hello, 

I have bought a dac with the AK4497EQ from China. The DC100 dac.
In there are 2 LME49710 opamps. For the fun i want to change the opamps.
Ive found already that a TI engineer adviced on the OPA1611 some time ago.
I have ordered some of these.

Now i see also on the TI website the OPA1692 and the OPA1622. 
Is it possible to try these opamps as a replacement? Maybe not because of the two channels?
Maybe other candidates?


----------



## raoultrifan

Hi, 

LME49710 is single opamps, while OPA1622 and OPA1692 are dual-opamps.
Probably OPA1611 would be a good choice. AD797 could be tested too.
You might also try BURSON SS V6 Classic/Vivid, though the price is a bit high maybe.


----------



## Rroff (Mar 12, 2018)

martist said:


> Now i see also on the TI website the OPA1692 and the OPA1622.
> Is it possible to try these opamps as a replacement? Maybe not because of the two channels?
> Maybe other candidates?



IIRC the 1622 is only available in VSON footprint and is functionally different to an 8 pin op amp single or dual so you'd need some kind of adapter board to make use of it and not just a "browndog" style adapter - it would need some (though minimal) additional supporting circuitry.

On another note my OPA2209s have arrived but having family over not had a chance to do anything with them yet.


----------



## endia (Mar 12, 2018)

Rroff said:


> IIRC the 1622 is only available in VSON footprint and is functionally different to an 8 pin op amp single or dual so you'd need some kind of adapter board to make use of it and not just a "browndog" style adapter - it would need some (though minimal) additional supporting circuitry.
> 
> On another note my OPA2209s have arrived but having family over not had a chance to do anything with them yet.



there is one, kind of "browndog" style adapter with additional components;
https://item.taobao.com/item.htm?id=556884462752

i had bought sometimes ago but burnt it while swapping.. in a very short listening period it was very promising..

actual build quality is much better then the ad..


----------



## martist (Mar 12, 2018)

Thx for the reply`s.

AD797 is now on my list.

For the OPA1622, the seller is also on Ebay, with that different ''browndog''.

Does it matter it is two channel?

The LME49710 i want to replace is one channel...


----------



## raoultrifan

You can't use dual opamps into single opamps schematic/design. You should stick to single channel opamps.


----------



## martist

Okay, all clear.


----------



## Rroff

endia said:


> there is one, kind of "browndog" style adapter with additional components;
> https://item.taobao.com/item.htm?id=556884462752
> 
> i had bought sometimes ago but burnt it while swapping.. in a very short listening period it was very promising..
> ...



I'm assuming that doesn't have a real connection to ground so compromises the performance?


----------



## raoultrifan

There's probably bypass caps on the motherboard/PCB itself, so I don't think there's a real compromise here. However, after opamp replacement a scope and audio signal tests should show us the truth.


----------



## endia

raoultrifan said:


> There's probably bypass caps on the motherboard/PCB itself, so I don't think there's a real compromise here. However, after opamp replacement a scope and audio signal tests should show us the truth.



exactly, I can't add anything to your explanation..


----------



## SpudHarris

Just realised I had a few Opa1641 modules in my collection for ages. Testing this evening and have to say I like them a lot. May be a little too analytical over time but initially I'm enjoying the detail...


----------



## imran27

Rroff said:


> IIRC the 1622 is only available in VSON footprint and is functionally different to an 8 pin op amp single or dual so you'd need some kind of adapter board to make use of it and not just a "browndog" style adapter - it would need some (though minimal) additional supporting circuitry.
> 
> On another note my OPA2209s have arrived but having family over not had a chance to do anything with them yet.


Waiting for your OPA2209 review


----------



## SpudHarris

As I haven't been on Head-Fi for a while I am still feeling my way around the site (and struggling...)

Is there any reviews on here for Muses 3? All the Muses I've had have been duals, is the 3 a single? It's expensive but I would still be interested...


----------



## raoultrifan

Couldn't find any, sorry.  However, as being single-opamps and designed for I/V it will be complicated to find someone actually paying so much money to test'em. I was thinking to do that mysel and put'em on DIP8 sockets, but I need 8 of them to use them in with PCM1795 or at least 4 of those to use'em with ES9018K2M...kinda expensive and a bit of DIY work.


----------



## DarkZenith

You can use MUSES03 in a lot of amplifying implementations as said in data sheet : "The MUSES03 features high quality sound, low input bias current, low noise, ultra low distortion and high slew rate, and it is suitable for *I/V converters*, *preamplifiers*, *active filters*, *headphone amplifiers*, and *line amplifiers*."
I put two at the gain stage of an iBasso P5 Falcon and they're working great, with a clear and punchy sound, very accurate and "musical" at the same time, without any harshness.


----------



## SpudHarris (Mar 15, 2018)

Just pulled the trigger on 2 x muses 3 from Audinst on EBay. They have great feedback and I am familiar with some of their products so fingers crossed its all legit...

I still keep coming back to OPA2209... No matter what I listen to nothing (yet) seems to grip me like the 2209. The musicality, depth and resolution especially with electronica is just amazing. Can't help but wonder how much better the Muses03 will be considering the cost difference.

I'll report back when Muses03 arrive...


----------



## nesty

Guys, is there an op amp that has the signature sound of an SS3602 sparkos? thanks


----------



## nesty

SpudHarris said:


> Got everything soldered up now so will be testing OPA2209 this evening... Sorry for the poor quality ipad pics.



Hi @SpudHarris , may I ask what are those resistors for? thanks


----------



## SpudHarris

Hi Nesty, they are a tweak for class A biasing. That module is for dual Opamps.


----------



## endia

SpudHarris said:


> Hi Nesty, they are a tweak for class A biasing. That module is for dual Opamps.



Hi @SpudHarris, why not to use a crd (ie 1n5298 a la MINT) since current will be vary with the signal in a resistor bias which means not a real bias..


----------



## nesty

SpudHarris said:


> Hi Nesty, they are a tweak for class A biasing. That module is for dual Opamps.



Hello @SpudHarris , just asking is that required for opa2209 because I thought it is plug in straightforward. Btw, how did you compute the values and which pins of the opamp are the resistors connected. thanks


----------



## Rroff

How do people find class A biasing? one of my amps has a dual jfet cascode and aside from 1-2 older op amps I've never noticed a difference - not scoped it ever to see what impact there is on crossover distortion but a lot of modern op amps kind of take care of that anyhow.


----------



## raoultrifan

http://www.eandiltd.com/pdf/class_a_vs_class_ab.pdf and https://www.sweetwater.com/forums/showthread.php?26210 explain pretty well the differences between Classes A and AB.

However, it would be interesting to compare distortions of an Class-A biased opamp vs. the same opamp but not-biased, of course...used in exactly the same config.


----------



## nesty

raoultrifan said:


> http://www.eandiltd.com/pdf/class_a_vs_class_ab.pdf and https://www.sweetwater.com/forums/showthread.php?26210 explain pretty well the differences between Classes A and AB.
> 
> However, it would be interesting to compare distortions of an Class-A biased opamp vs. the same opamp but not-biased, of course...used in exactly the same config.


thanks very informative. Question: is it audible between biased and unbiased?


----------



## raoultrifan

Technically speaking, THD differences between class-A and class-AB are measurable indeed, but shouldn't be quite audible...well, unless someone with golden ears is around.


----------



## FritzS

raoultrifan said:


> Technically speaking, THD differences between class-A and class-AB are measurable indeed, but shouldn't be quite audible...well, unless someone with golden ears is around.



The difference are only TIM and Crossover Distortion. But they are measurable and hearable in Class AB Diamond buffers (Walt Jung) - discrete or IC (looks like BUF634, LME49600, LME49610, LMH6321, ....)?
The most buffers have a Quiescent Current more than 15mA in wide bandwith mode (BUF634). This will drive the most headphones in lower hearing levels in Class A.
Two buffers in parallel they have 30mA Quiescent Current.

https://en.wikipedia.org/wiki/Crossover_distortion
https://electronics.stackexchange.c...es-and-capacitors-reduce-crossover-distortion
http://www.aikenamps.com/index.php/what-is-crossover-distortion
http://abacus-audio.org/files/akademie-6.pdf
http://www.jockohomo.net/data/7470.pdf


----------



## raoultrifan (Mar 19, 2018)

I've seen myself the 3rd harmonic lowering just a little bit when setting the BUF634 to wide-mode, most likely IMD decreased a bit too (haven't measured it across entire spectrum), however PASSLAB explains it pretty well here: https://www.passlabs.com/press/leaving-class.
And I also agree with their answer: https://www.passlabs.com/press/class-or-class-ab-classless-society, mostly because usually choosing a good PSU and the right components is more important that biasing into class-A.

However, looking forward to see some measurements of a regular opamp vs. the same, but biased into class-A. It would be quite interesting to find a good candidate, especially if used in I/V, LPF or voltage-gain.


----------



## martist

Maybe a dumb question. Is it possible to put the NE5534 in the place of the lme49710?

The stock opa is the lme49710.

The way around is possible, i read everywhere.

Like earlier said. Just for fun , i want to know if i can hear better or worse audio.


----------



## raoultrifan

Well, some might say it's a downgrade...and if you look at their datasheets then LME49710 could be a better option.
What's your device, please?


----------



## ZappaMan (Mar 18, 2018)

I was thinking of upgrading my stx 2, with the bursen v6 op amp. Anyone looking to sell theirs? Or anyone have any other recommendations. I like all sorts of music, but really liking aphex twin at the minute, so something suited to EDM would be cool. But also can’t stop listening to DSOTM !


----------



## raoultrifan

There's an STX already upgrade on this forum upgraded with V5 SS (can't tell where, please dive deep into the search), there's also a review with SS V6 few pages back. I'm sure you can do it with ease, but you might want to measure twice the space left for the opamps to get installed.


----------



## martist (Mar 19, 2018)

''Well, some might say it's a downgrade...and if you look at their datasheets then LME49710 could be a better option.
What's your device, please?''

I want to hear the differences, if i can. Just for fun.

Dac100 with AK4497  from China. ( the version with two power trafo)


----------



## imran27

martist said:


> Maybe a dumb question. Is it possible to put the NE5534 in the place of the lme49710?
> 
> The stock opa is the lme49710.
> 
> ...


It's a downgrade

Try AD797 or OPA189.

Members here have reported good things about OPA189


----------



## martist

Some say the distortion from the ne5534 sounds nice. Ive read so many opinions on the net. 
I have them around. So that is why i ask if i can put them in that circuit? I want to know if i can hear the downgrade. If i cant hear the downgrade, why bother with other opamps.

(opa1611 is on the way)

AD797 sometimes needs a bypass , ive read?  opa189 is on the list.
What about opa827, is that even possible because it is jfet?


----------



## raoultrifan

martist said:


> I want to hear the differences, if i can. Just for fun.
> 
> Dac100 with AK4497  from China. ( the version with two power trafo)



I know what you're saying...also, most of the recording studio gears are using NE5532 or NE5534, so "live studio sound" is already recorded and post-processed by using the NE opamps. 

However, is it this DAC: http://www.ebuy7.com/item/efdfefdjadia? I only see SO8/SOIC LT opamps. Perhaps some close-up pics might help.


----------



## martist (Mar 19, 2018)

https://www.aliexpress.com/item/201...2bf1-4289-b16f-671c3521819f&priceBeautifyAB=0


And thx for thinking with me.


----------



## nesty

Very nice. Guys, what are your devices that you use when evaluating op amp rolling. Any recommended ones? thanks


----------



## raoultrifan

martist said:


> [...]https://www.aliexpress.com/item/201...2bf1-4289-b16f-671c3521819f&priceBeautifyAB=0
> 
> 
> And thx for thinking with me.



In AKG's evaluation board they're using AD817A/AN, so you might want to test this opamp too, I guess.


----------



## martist

What do you guys think of this version of the opa1611? Is it fake? Trustable to use in my dac circuit? I have one standard version opa1611 on the way, which doesnt have the increased output , they claim in the Ebay ad.

https://www.ebay.nl/itm/New-OPA1611...244403?hash=item1c985be873:g:UeYAAOSwCJxZ6wga


----------



## dumbears (Mar 21, 2018)

Sorry, I wasn't seeing the pic correctly.


----------



## Rroff

Whether it is any good or not is one question but that is pretty ingenious none the less.


----------



## SpudHarris

martist said:


> What do you guys think of this version of the opa1611? Is it fake? Trustable to use in my dac circuit? I have one standard version opa1611 on the way, which doesnt have the increased output , they claim in the Ebay ad.
> 
> https://www.ebay.nl/itm/New-OPA1611...244403?hash=item1c985be873:g:UeYAAOSwCJxZ6wga



Well I've just ordered a couple for the hell of it...


----------



## martist

Me to.


----------



## martist

What about this item?  A soic8 to dip8 tool.

Can i use that without soldering? On YouTube it is like that.

https://www.ebay.com/itm/SOIC8-SOP8...-Converter-Module-150mil-200mil-/401245634475

Just use two of these.


----------



## Rroff

A lot of those use square pins that might not fit into the round holes on your average high quality DIP8 socket - but fit fine into the older styles ones and the cheap and nasty sockets.

They aren't a bad option for testing stuff and can be used without soldering but they have fairly long connections which isn't ideal if that means decoupling capacitors, etc. are a long way from the opamp.


----------



## Rroff (Mar 28, 2018)

Hadn't forgotten about the OPA2209 but got side tracked with this little project which I decided to use them in:






Started out with such intentions but ended up a bit messy and cramped - but seems to achieved what I set out to do none the less (another USB powered O2 variant that keeps as much of the performance of the original on prototype board while being, relatively speaking, easy to build).

"Proof of life":





As this is a newly built amp I can't directly compare against much else other than I've run 3x OPA2209 and 3x OPA1612 through it to listen to.

Would definitely agree that the OPA2209 seems like a more reference sound OPA1612 - it also has noticeably decent noise and EMI/RF resilience when used on an open prototype board like above 

Nice detail and texture as imran27 noted I find the mid-range is a little prominent but at the same time there is no lack of soundstage with certain instruments, etc. standing out well as they should be with a sense of depth. None of the at times synthetic "twang" of the 1612 very neutral but without sounding dry like the OPA1602 or LME4xxxx, etc. treble could do with a touch more life maybe but can't really fault it otherwise.

Overall pretty impressed with it - can see it being my go to its a nice blend of all the things I love about the OPA2228, AD8066 and OPA1612 with less of the downsides.


----------



## SpudHarris

Like the look of that Rroff will you roll that out or is it just a personal project?


----------



## Rroff (Mar 30, 2018)

SpudHarris said:


> Like the look of that Rroff will you roll that out or is it just a personal project?



Just a personal project it isn't particularly cost effective in implementation - happy to answer any questions about it, etc.

Not really the thread for it but quick run down on parts used:



Spoiler



-2x DCP020507 (single output) DC-DC POL for converting USB power to +/-7V rails + isolation.
-Panasonic FC 4.7uf on the input to the DCPs.
-Cornell Dubilier 470uf MLQ series used for the main cap bank
-LM2990T/LM2940T (5 volt fixed) regulator pair - not my first choice as noise performance is so-so but low voltage drop, reasonably low quiescent current but means minimal circuitry over the better LM317/337 setup which I generally prefer - goal was to keep it simplified as much as possible while retaining as much performance as possible.
-Nichicon 220uf and 10uf KZ (Muses) used for providing local power and bypassing the input stage
-Wima MKP4 (new variant) polypropylenes for the film caps
-Conductive plastic 10K pot - (Vishay P9A2R100FISX1103ML)


----------



## Rroff

This opamp is so not forgiving for tunes with a lot of mushiness from compression, etc.  one of the reasons I still use the OPA2228 at times is that it tends to flatter the average MP3 encoding while still producing high quality results when fed from better sources.


----------



## imran27

Rroff said:


> This opamp is so not forgiving for tunes with a lot of mushiness from compression, etc.  one of the reasons I still use the OPA2228 at times is that it tends to flatter the average MP3 encoding while still producing high quality results when fed from better sources.


Yeah indeed. OPA2209 is crazy fast, the attack and decay is insane.

I tried many IEM's at CanJam SG and also at Music Sanctuary, the differences in attack speed of various IEMs was so clear.

Some IEM makers praised the transient performance of XD-05 (with OPA2209 and bypass caps on BUF634)

I just revisited some of the opamps I had after adding bypass caps over BUF634 in my XD-05.

OPA2192 is like the next best thing after OPA2209: Slight mid bass emphasis, more fleshy mid range, less texture compared to OPA2209 and highs start to recess and roll off not very steep roll off though so you have the extension in highs but it feels more musical and forgiving. Same applies for the bass. And soundstage is more intimate, doesn't have the depth and placement of OPA2209. If you like OPA2209 but want something forgiving and engaging without sacrificing a lot of details, OPA2192

OPA1662: When it comes to detail resolution, this is second only to OPA2209 but OPA1662 also has a pretty dry untextured (I mean not satisfactorily textured) mid range and quite recessed. Soundstage is adequately wide and engaging.

LME49720: Lower mids and mid emphasis (slight), in terms of texture this is second to OPA2209, bass and treble extensions are not very good, soundstage is very very intimate, layering is decent. Bass sometimes masks lower mid range details.

I can't see anything replacing OPA2209 anytime soon.

Maybe OPA2189 (or dual OPA189) or OPA1692 but they are in preview still


----------



## Bluess

imran27 said:


> Yeah indeed. OPA2209 is crazy fast, the attack and decay is insane.
> 
> I tried many IEM's at CanJam SG and also at Music Sanctuary, the differences in attack speed of various IEMs was so clear.
> 
> ...


Can you be more specific with which opa2209 you are using? I see tons of them on mouser and don't know which version would be best


----------



## imran27

Bluess said:


> Can you be more specific with which opa2209 you are using? I see tons of them on mouser and don't know which version would be best


Well, SOIC 8 pin

TI doesn't have any design variations. Most of the different ones you see on distributor websites are just different packaging and gradings like automotive etc.

Just get the cheapest soic8 version


----------



## SpudHarris

Look what the Easter Bunny brought this morning...


----------



## Bluess

imran27 said:


> Well, SOIC 8 pin
> 
> TI doesn't have any design variations. Most of the different ones you see on distributor websites are just different packaging and gradings like automotive etc.
> 
> Just get the cheapest soic8 version


Thanks,


----------



## Rroff (Mar 31, 2018)

Yeah the different versions (so far) are just the package style and distribution type i.e. tape, reel, ammo pack, etc. (which only matters if you are using them professionally in machine assembly, etc.) other than some of those have an additional cost or minimum order quantity. Probably ones for grading like automotive as well but didn't really pay attention to that.



SpudHarris said:


> Look what the Easter Bunny brought this morning...



Nice.

Though I throw a fair amount of money at this hobby I'd really have to try before I bought for those heh - though the older ones were nice they didn't justify the cost for me over the alternatives.


----------



## SpudHarris

It's too early to comment really but I really do like them so far. Problem I have is I have been breaking in HD800S and all previous/recent OpAmp evaluation has been with HD800 so thought it would be sensible to stick with them. It's killing me looking at at the 800S but will drop critical OpAmp evaluation for a while tonight for a bit of fun listening...


----------



## toear

Hi All

I've been lurking here and reading through the pages trying to glean some understanding and ideas for opamp mods. I recently ordered a Vishan V2 based on reviews and user feedback, but mostly overlooked any comments based on switching the opamp... then I started reading those... then I got it in my head that there was indeed doable/achievable 'tinker-room' with this device based on my resources (this place is very bad for that!...)

Anyway, I came across all the reviews for the Burson v5i, v5, and v6 variations and thought 'cool!... i could switch a chip and play...', then I looked at the cost to Canada. Given the Vishan was under $50CAD shipped I am hesitant to spend another ~$60+USD for an opamp to experiment with (with the reality that I may actually break both in the process).

The Z2 comes with a TI LM4562NA (which I am assuming is the same when referenced as a LM4562).  I am looking for an upgrade that is good at presenting soundstage/detail/separation, but in a way where the listener is in the audience (vs 'on stage' not unlike the presentation given with Fiio X5 gen 1 LMH6643 used for headphone output (if I understand correctly) where the listener is 'in' the band).

I have read that possible affordable 'upgrades' would be opamps like:
- TI LME49720
- TI OPA1652
- TI LME4970

From what I can tell (through Mouser) these chips are more affordable/doable... I looked at options like MUSE as well but they are even more expensive than the Bursons.

(Yes... I know I don't even have the unit yet and don't actually know what it sounds like... this has more to do with the mod/tinker/just-because side of me... , either way, I would be ordering blind, though I won't )

If anyone has any other 'cost-effective' (as little as possible to ~$30 CAD delivered) suggestions this would be greatly appreciated! Or... if there is not really a good 'affordable' upgrade (anything worth doing is going to cost me) and I should just use as is, that wisdom would also be appreciated...

Thanks!


----------



## dumbears

toear said:


> Hi All
> 
> I've been lurking here and reading through the pages trying to glean some understanding and ideas for opamp mods. I recently ordered a Vishan V2 based on reviews and user feedback, but mostly overlooked any comments based on switching the opamp... then I started reading those... then I got it in my head that there was indeed doable/achievable 'tinker-room' with this device based on my resources (this place is very bad for that!...)
> 
> ...



Interesting to know the new batch of Z2 employs 4562.  The old batch used 2604.

Perhaps, you may want to take a look at the OPA1662.  It's less noisy than OPA1652 and it's more power efficient.  However, you may as well want to check the input resistance to it.  If it's > 5K, you may want to go for 1652 instead.  Pls check the datasheet for detail.  For 49720, you may want to try the metal cap version, LME49720HA or you may want look for LME49990 x 2 (you need 2 to work, pls check carefully).  Moreover, you may want to get your hands onto the MUSES 8920, which some said it's the so-called downgraded MUSES01.

Just from the top of my head.  There should be a long list.


----------



## raoultrifan

SpudHarris said:


> Look what the Easter Bunny brought this morning...



Nice, indeed! Too bad of the high price, as I need 4 or 8...or more, depends.  Plus single-to-dual adapters, so very pricey I'd say.


----------



## toear (Apr 4, 2018)

dumbears said:


> Interesting to know the new batch of Z2 employs 4562.  The old batch used 2604.
> 
> Perhaps, you may want to take a look at the OPA1662.  It's less noisy than OPA1652 and it's more power efficient.  However, you may as well want to check the input resistance to it.  If it's > 5K, you may want to go for 1652 instead.  Pls check the datasheet for detail.  For 49720, you may want to try the metal cap version, LME49720HA or you may want look for LME49990 x 2 (you need 2 to work, pls check carefully).  Moreover, you may want to get your hands onto the MUSES 8920, which some said it's the so-called downgraded MUSES01.
> 
> Just from the top of my head.  There should be a long list.



Thanks for chiming in... much appreciated!

I took a look at the OPA1662 and there was a recommendation on the page for the OPA1692 ('To achieve lower distortion at much lower power consumption (650µA/ch) for wireless microphones and USB audio applications')(http://www.ti.com/product/OPA1692)... a better/upgraded version?... besides lower power consumption I am not sure that wireless microphones and USB audio applications are relevant to this situation.

I have taken a look at a few primers for how to read opamp datasheets and have tried to make sense of what I am looking at ... (I have to admit that most of it doesn't make any sense)... but I will keep reading.

When you refer to input resistance >5K, are you referring to 'common mode' or 'differential'?
This is what I found for the OPA1662/OPA1664:
Differential 170 || 2 kΩ || pF    Common-mode 600 || 2.5 MΩ || pF

Thanks again for your help!


----------



## imran27

toear said:


> Hi All
> 
> I've been lurking here and reading through the pages trying to glean some understanding and ideas for opamp mods. I recently ordered a Vishan V2 based on reviews and user feedback, but mostly overlooked any comments based on switching the opamp... then I started reading those... then I got it in my head that there was indeed doable/achievable 'tinker-room' with this device based on my resources (this place is very bad for that!...)
> 
> ...


LM4562 itself is pretty decent.

As upgrade you can go to OPA1612: Huge sub bass, holographic soundstage, musical highs.

Or my long time favourite OPA2209 or my recent favourite OPA1692 (VSSOP-8)


----------



## imran27

OPA1692



Spoiler: IMAGES



















OPA1692 (VSSOP-8) vs LM4562 (SOIC-8), size comparison



Pre ordered this thing more than 2 months ago IIRC, came in today, from element14

Now the surprise, or rather something I forgot about this was that it is a VSSOP-8 package not a SOIC-8 package. Fortunately the adapter boards I had support both packages.

TL; DR
Yes, this one stays in my XD-05. It has dethroned OPA2209

First thing I noticed: Such a clean and speedy attack and an insanely dark and silent background.

In fact the background is so dark and silent it confused me into believing that OPA2209 is more detailed. But it turns out OPA2209 has a brighter/noisiser background compared to OPA1692.
Just imagine, the opamp I was raving about is now just a piece of trash. (Not really, still a pretty amazing opamp). Everything will be a comparison to OPA2209

Detail resolution is indeed much better, bass depth and treble extension is better.
The highs are the cleanest and most detailed I've heard.
Texture is available without any graininess.

The layering is amazing, it can present different layers to something where even OPA2209 would struggle.

Soundstage as such is more precise and engaging.

Now I'll be waiting to check out OPA2189/OPA189.

All opamp rollers, I highly recommend this opamp. Check out if someone is selling premounted on eBay. Otherwise get your hands dirty, it's well worth it.

Please, don't even mention LME49720, it's not even in the same league.

As far as specs are concerned, OPA2209, OPA2189 & OPA1692 are the 3 best followed by OPA2192

And based on my listening, yes specs do mean better sound. Especially small signal and large signal response for G = +1, CMRR & Open Loop gain, Phase response (flat phase in audio spectrum is better).


I highly recommend this opamp.

Hopefully I receive my Burson Play replacement soon so that I can try this thing in Play. The higher detail resolution and transparency of ES9018K2M would be the real test for this opamp Even in Play, OPA2209 is my favorite (Only played with I/V stage)


----------



## toear (Apr 4, 2018)

imran27 said:


> OPA1692
> 
> 
> 
> ...



Thanks for your suggestions and sharing your most recent experiences. 

I noticed that these ic chips are tiny. My understanding is that I would have to solder them onto some kind adapter so they would work in a dip 8 package?

Also, when ordering, how would I tell which one to order of a particular model. There are a combination of letters following the chip model (e.g. OPA1692AID vs OPA1692AIDR)...more specifically for the Zishan Z2, which I believe is a dual version dip8 configuration...

Also, the nice surprise with these suggestions is that I just put 3 opamps into my Mouser cart and with shipping it was under $30! Much more doable compared to the Burson and Muse options, and I can experiment... 

Again much appreciated to ask the responses!


----------



## imran27

toear said:


> Thanks for your suggestions and sharing your most recent experiences.
> 
> I noticed that these ic chips are tiny. My understanding is that I would have to solder them onto some kind adapter so they would work in a dip 8 package?
> 
> ...


What I follow is
"Cheapest DIP-8 or SOIC-8 part available for the same part", only suffix changes

So AID, AIDR, AIDGKT etc., doesn't matter. Get the cheapest one which is in DIP-8 or SOIC-8

And yes, you need SOIC-8 to DIP-8 adapter boards.


----------



## nesty

imran27 said:


> OPA1692
> 
> 
> 
> ...





imran27 said:


> OPA1692
> 
> 
> 
> ...


Hi @imran27 , which is bigger the soic or vvsop? I have an soic pcb board adapter to dip but underneath the board there is a footprint for soldering another chip but I'm not sure if it is for the vssop.


----------



## imran27

nesty said:


> Hi @imran27 , which is bigger the soic or vvsop? I have an soic pcb board adapter to dip but underneath the board there is a footprint for soldering another chip but I'm not sure if it is for the vssop.


VSSOP-8 is smaller one. I guess I am using one of those similar boards. SOIC-8 on one side and VSSOP-8 on another


----------



## dumbears (Apr 5, 2018)

nesty said:


> Hi @imran27 , which is bigger the soic or vvsop? I have an soic pcb board adapter to dip but underneath the board there is a footprint for soldering another chip but I'm not sure if it is for the vssop.





You need sth like the right one in the pic.  The left is for SOIC.

I don't sell them, but all I can tell is they can be found in AliExpress.


----------



## endia

imran27 said:


> OPA1692
> 
> 
> 
> ...



@imran27, thanks for the impressions.. it seems that TI raised the bar pretty much.. since you are responsible for my enjoyment about opa2209 in my zishan dsd, now it's a must to try OPA189 too..


----------



## rikk009

imran27 said:


> OPA1692
> 
> 
> 
> ...


Can't find OPA1692 on element14, can you link it here? And on mouser I can only find it in VSSOP.


----------



## imran27

rikk009 said:


> Can't find OPA1692 on element14, can you link it here? And on mouser I can only find it in VSSOP.


Element14 Malaysia!

Yes, it is in VSSOP-8 package only


----------



## dumbears

rikk009 said:


> Can't find OPA1692 on element14, can you link it here? And on mouser I can only find it in VSSOP.


I'm in Hong Kong.  Here is the link of OPA1692 (OPA1692IDGKT) in Element14: http://hk.element14.com/texas-instr...2&ddkey=http:en-HK/Element14_Hong_Kong/search

Sorry, it only exists in VSSOP.


----------



## toear (Apr 7, 2018)

imran27 said:


> What I follow is
> "Cheapest DIP-8 or SOIC-8 part available for the same part", only suffix changes
> 
> So AID, AIDR, AIDGKT etc., doesn't matter. Get the cheapest one which is in DIP-8 or SOIC-8
> ...



@imran27 - Thank you for the clarification!

The next challenge I seem to be facing is finding parts in or for Canada... or rather, does anyone know of a Canadian-based distributor for these parts? I have come across parts availability for Canada (e.g. no SOIC-8 to DIP-8 adapters available for shipment to Canada from Mouser... a regional thing?) I would prefer not to have to order multiple parts from multiple places as this increases shipping costs significantly...


*edit*- or does anyone have suggestive for parts abroad? Specifically soic8 to dip8 and Vssop8 to dip8 adapters?  I've come across some that look like sheets of pcbs and some with out pins (just the board) and an not sure exactly which one will have all the parts... Or better yet a good ebay (or otherwise) seller that sells these pre-soldered? I am looking to try the opa1692 and the opa2209... For starters...  

TIA!


----------



## SpudHarris

I ordered 2 of those Opa1611 modules. Very nice opamp anyway but I am captivated by these modules. For the price these are a steal... Oh and the underside has LED's. Bonus!


----------



## Rroff

Those are LEDs on the underside? wondered what they were - wonder if they are used as a voltage reference or just for show.

Might throw some OPA1692 in with my next order I'm doing soon though from the description sounds like they will have me wanting the AD8066 which does inky blackness and deep layered sound so well when setup right.


----------



## imran27

Yesterday again, tried my XD-05 with Stealth Sonics U9 and U4 IEMs

Every opamp in my collection was noisy and unjustified to drive them. Only OPA1692 did justice that it was very silent, had an amazing attack and decay.

OPA2209 is the noisiest but also the most transparent and detailed. If only the hissing could be tamed I am sure OPA2209 can smoke every other opamp.


----------



## toear

imran27 said:


> Yesterday again, tried my XD-05 with Stealth Sonics U9 and U4 IEMs
> 
> Every opamp in my collection was noisy and unjustified to drive them. Only OPA1692 did justice that it was very silent, had an amazing attack and decay.
> 
> OPA2209 is the noisiest but also the most transparent and detailed. If only the hissing could be tamed I am sure OPA2209 can smoke every other opamp.



For the OPA1692 did you solder it yourself? And if so, where/what kind of adapter did you get/use?

I managed to find a pcb that matches a Us8 package to dip8, and my understanding is that vssop8 is the same as us8?

Or could you recommend a supplier that sells the opa1692 mounted?

Thank you


----------



## imran27

toear said:


> For the OPA1692 did you solder it yourself? And if so, where/what kind of adapter did you get/use?
> 
> I managed to find a pcb that matches a Us8 package to dip8, and my understanding is that vssop8 is the same as us8?
> 
> ...


https://www.aliexpress.com/item/20p...SMD-to-DIP-0-65-1-27mm-pitch/32774064574.html

Can't guarantee quality though.

Seems to have good reviews


----------



## toear

imran27 said:


> https://www.aliexpress.com/item/20p...SMD-to-DIP-0-65-1-27mm-pitch/32774064574.html
> 
> Can't guarantee quality though.
> 
> Seems to have good reviews



bingo! Thank you!!


----------



## Rroff

imran27 said:


> Yesterday again, tried my XD-05 with Stealth Sonics U9 and U4 IEMs
> 
> Every opamp in my collection was noisy and unjustified to drive them. Only OPA1692 did justice that it was very silent, had an amazing attack and decay.
> 
> OPA2209 is the noisiest but also the most transparent and detailed. If only the hissing could be tamed I am sure OPA2209 can smoke every other opamp.



I've not noticed any background noise to speak of with the amp I posted with the OPA2209s - I've a bunch of Sennheisers including Momentums (which don't need amping but reveal noise due to sensitivity), various IEM models, HD600 and HD650 and some varied Beyerdynamics and a pair of Sony MDR. The only opamps really I notice any noise with that kind of design are the LM4562 and LME4xxxx series which seem a touch more susceptible to stray EMI/RF than most, unless you take additional steps to shield them, for some reason.


----------



## imran27

Rroff said:


> I've not noticed any background noise to speak of with the amp I posted with the OPA2209s - I've a bunch of Sennheisers including Momentums (which don't need amping but reveal noise due to sensitivity), various IEM models, HD600 and HD650 and some varied Beyerdynamics and a pair of Sony MDR. The only opamps really I notice any noise with that kind of design are the LM4562 and LME4xxxx series which seem a touch more susceptible to stray EMI/RF than most, unless you take additional steps to shield them, for some reason.


In XD-05 OPA2209 is quite noisy.

About LME, yeah they are susceptible. I hear interference as soon as I open whatsapp of facebook on my phone near my XD-05 while using LME49720 or LM4562

I suspected it could be the PSU noise (XD-05 uses boost converters to get +/-9 VDC, but then OPA2209 has a  better PSRR than OPA1692.

The only place where OPA2209 looks worse is the Open Loop Gain, CMRR and Slew Rate.


----------



## nesty

SpudHarris said:


> I ordered 2 of those Opa1611 modules. Very nice opamp anyway but I am captivated by these modules. For the price these are a steal... Oh and the underside has LED's. Bonus!



@SpudHarris , what is your test unit where you place those opamps? thanks


----------



## SpudHarris

nesty said:


> @SpudHarris , what is your test unit where you place those opamps? thanks



Nesty, it's the Burson 'Lycan' it's just an honest testbench. Not flashy nor overly expensive but a great amp for rollers...


----------



## Rroff

SpudHarris said:


> Nesty, it's the Burson 'Lycan' it's just an honest testbench. Not flashy nor overly expensive but a great amp for rollers...



Always the best kind of test bench - I mainly use a glorified (better power supply) CMOY type circuit - but I've worn out some of the connections from plugging things in and out so need to rebuild it :s


----------



## SpudHarris

I'm sure the original power supply was good but I swapped it out for a Graham Slee PSU1 which I have always rated highly.

I forgot how much fun rolling was... The Opa1611 modules I bought are really quite amazing. Will drop some standard ones in tonight to compare


----------



## nesty

SpudHarris said:


> Nesty, it's the Burson 'Lycan' it's just an honest testbench. Not flashy nor overly expensive but a great amp for rollers...


@SpudHarris , that's great but sadly Burson already stopped the mass production of Lycan. You're lucky to have one.


----------



## FritzS

SpudHarris said:


> I'm sure the original power supply was good but I swapped it out for a Graham Slee PSU1 which I have always rated highly.
> 
> I forgot how much fun rolling was... The Opa1611 modules I bought are really quite amazing. Will drop some standard ones in tonight to compare



I own an Graham Slee Solo to, its older and one of the „green series“ - with switch PSU. I want to mod this amp. 
Currently it have 33 Ohm in series to the output. This is to high for some low impedance headphones, so as AKG K812.


----------



## raoultrifan

Hi FritzS, 

If it's about this schematic found on AliExpress https://ae01.alicdn.com/kf/HTB1d9Fh...r-f-rence-Grammy-Graham-Slee-SOLO-Hifi-fi.jpg then I'd say to leave it as it is, mostly because the BC550/560 were not meant to drive low impedance sources. The amp itself is probably very low noise and of good quality to drive high impedance cans instead, so I would keep it for this purpose mainly.

If still want to dive deeper into this, then you cold try adding an output buffer like Lehman here: https://cdn.head-fi.org/a/6666954.jpg. Without having a powerful output buffer I can't recommend you to lower the existing output resistors.

P.S.: Having an output buffer in place could make the output resistors to disappear or at least to notched them down near to few ohms only, as per https://www.head-fi.org/threads/asu...-dac-cebit-2011.542563/page-235#post-14145076.


----------



## raoultrifan

On a 2nd thought, paralleling BC550/560 (like you've done it here: http://www.blue-danube.at/hifi/wna.php#Modification1) could do the job and let you lower the output resistance after all, but don' remove the output cap because the DC could be higher.
https://www.edn.com/Pdf/ViewPdf?contentItemId=4434614

Good luck and please let us know of the results! If you have access to a scope then please share initial and final results when sine and square waves are applied.


----------



## FritzS

@raoultrifan 
thank you for this hints.

You bring me an idea.
Another way would be to replace the two end-stage transistors with BUF634.
I have some of them in stock.

AKG K812 don't like the 33 Ohm in series to the output. My model use 33 Ohm resistors instead 120 Ohm here
https://ae01.alicdn.com/kf/HTB1d9Fh...r-f-rence-Grammy-Graham-Slee-SOLO-Hifi-fi.jpg


----------



## raoultrifan

The BUF634 need to be inside the loops of the opamp, otherwise will not be stable. This will completely modify the amplifier and you might want to rename it.


----------



## raoultrifan

Schematic could be identical with LME49720/LME49600 amplifier design from TI datasheet; I've used it in the past with LME49720/BUF634 with success. The BUF634 were DIP8 with heatsinks applied on top.

However, https://www.by-rutgers.nl/HeadPhoneAmp.html could be also a good one.

Good luck and keep us posted.


----------



## FritzS

@raoultrifan 
I own an older Solo and a mod WNA MKII too. Now Jan Meier have loan me a Corda -ff (1) for two weeks (and to present it on the Vienna head-fi meeting). Jan use AD797 and BUF634. I had two AD797 in my stock, so I put them into my WNA instead of OPA627. This put the WNA a bit closer to Corda -ff (but not the same performance). 
I think about some mods and to buy an headphone amp (like Corda) too.

As SOIC coming, I don't like to make some self with this. WNA MKII was my last project, only I changed OPAs in WNA or Solo.

You know about this site: 
http://www.blue-danube.at/hifi/wna-main.php

(1)
http://www.meier-audio.homepage.t-online.de/classic.htm


----------



## bsoplinger

SpudHarris said:


> I ordered 2 of those Opa1611 modules. Very nice opamp anyway but I am captivated by these modules. For the price these are a steal... Oh and the underside has LED's. Bonus!


I'd want the OPA1611AID to use in a dual channel item like the Xduoo XD-05, correct?


----------



## imran27

bsoplinger said:


> I'd want the OPA1611AID to use in a dual channel item like the Xduoo XD-05, correct?


Why do you want OPA1611? XD-05 by default comes with OPA1612 which is a dual version of OPA1611 (Or OPA1611 is the single version of OPA1612 whichever way you want to look at it)


----------



## skwoodwiva

Bilavideo said:


> I bought a Cmoy from BSG who installed an Opa 2227 and, for a few dollars more, sent me an LRM4562. After that, I got so excited about opamp rolling that I went through Ebay (bad idea), Digikey and AD for more. I've tested the 627BP, AD8599, AD8066, AD797, Opa27, AD823, AD825 and a few more. For single opamps, I went through Cimarron Technologies to order Browndog Adapters.


I this anybody's favorite also?


----------



## bsoplinger

imran27 said:


> Why do you want OPA1611? XD-05 by default comes with OPA1612 which is a dual version of OPA1611 (Or OPA1611 is the single version of OPA1612 whichever way you want to look at it)


Umm, well actually I was thinking more of using it in the little bear tube amp actually but XD-05 was shorter to write and I figured that more people would be aware of the it versus the little bear since the whole changing an opamp process is new to me. I didn't really realize exactly what the XD-05 came with by default. That actually makes getting it a better purchase because I could just move the OPA1612 from the XD-05 to the little bear and get something nicer to try in the Xduoo XD-05.


----------



## bsoplinger

skwoodwiva said:


> I this anybody's favorite also?


Out of curiosity, which opamp does the word this mean in your question?


----------



## raoultrifan

Usually op-amps could be "favorite" based on the stage it is used for. For me the list is not big:
- I/V conversion: AD797, MUSES01 and 8920, also AD8599
- LowPassFilter: BURSON SS V6 Classic, MUSES02, MUSES8820, LME49720 (also AD797 if singles are required)
- VoltageAmplificationStage: BURSON SS V6 Classic, OPA1652, LME49720, OPA2132
- Output buffer: BURSON SS V6 Classic, MUSES02, MUSES8820, LME49720

However, depending on the configuration and designed used some other opamps could be recommended. If in doubts, then LME49720/LM4562/NE5532 could be a good match.

Now speaking about Xduoo XD-05, I wouldn't change any opamps in there, as the OPA1612 is the recommended one for AK4490; also, it's specs are top of the line.


----------



## Rroff

Have to say I'm not a big fan of some of the big old favourites like the AD797, OPA627, etc. not that there is anything wrong with them as such just the sound isn't for me. AD8066 is a long time favourite but not an easy one to get the best results with (its performance can be significantly enhanced with external capacitors).

These days OPA1612 features in a lot of my usage though getting the itch to explore a few of the newer options.


----------



## raoultrifan (Apr 14, 2018)

AD797 (BJT-input) and AD8599 (BJT-input) are extremely low noise opamps: 0.9nV/√Hz at 1 kHz and 1.1nV/√Hz at 1 kHz, so for really low-noise applications worth trying.
I'm glad OPA1612 exists, as it's also a very low-noise opamp too: 1.1nV/√Hz at 1 kHz.

Fell free to try 4.5nV/√Hz at 1 kHz in I/V or LPF or VAS stages vs. 0.9nV/√Hz at 1 kHz and you'l realize yourself the background noise difference with sensitive cans or with proper measurement equipment.


----------



## skwoodwiva (Apr 13, 2018)

bsoplinger said:


> Out of curiosity, which opamp does the word this mean in your question?


You seem to lean to the LRM4562 yet opa is close?
1st line...
These will go ob my Krk boards.
https://www.head-fi.org/threads/a-krk-woody-tower-fun.876953/


----------



## FritzS (Apr 14, 2018)

raoultrifan said:


> AD797 (FET-input) and AD8599 (BJT-input) are extremely low noise opamps: 0.9nV/√Hz at 1 kHz and 1.1nV/√Hz at 1 kHz, so for really low-noise applications worth trying.



AD797 is an BJT-input, please see page 11
http://www.analog.com/media/en/technical-documentation/data-sheets/AD797.pdf

AD8599 seems an BJT too
http://www.analog.com/media/en/technical-documentation/data-sheets/AD8599-EP.pdf

AD797 does a better work as OPA627 or Supreme Sound Opamp V5 in my WNA MKII
This I had tested too LM6171, AD843, AD847, LT1056, LT1022, OPA602, TLE2071.


----------



## raoultrifan

Thank you FritzS, I had modified my previous post.


----------



## Rroff

skwoodwiva said:


> You seem to lean to the LRM4562 yet opa is close?
> 1st line...
> These will go ob my Krk boards.
> https://www.head-fi.org/threads/a-krk-woody-tower-fun.876953/



LM4562 is pretty decent - lots of detail, fairly low noise and handles audio like loads well on the down side it has a touch of cold and brittleness to the sound and is quite easily upset by PSU noise - in my experience you need to pay attention more to trace routing and shielding more than some other opamps to get good results in that respect - while stuff like the OPA1612 seem far more resilient to stray EMI/RF and PSU noise etc.


----------



## skwoodwiva

Rroff said:


> LM4562 is pretty decent - lots of detail, fairly low noise and handles audio like loads well on the down side it has a touch of cold and brittleness to the sound and is quite easily upset by PSU noise - in my experience you need to pay attention more to trace routing and shielding more than some other opamps to get good results in that respect - while stuff like the OPA1612 seem far more resilient to stray EMI/RF and PSU noise etc.


Will order today, going on 2 different boards

  

What do you think?
I did much of this kind of swap in all my Sony ES stuff. They being so good anyway... I did notice the 6171 was better than stock


----------



## Mad Max

If you end up not liking those LM4562s in place of the Rokit boards' NJM4580s, try TL5580A or ADA4610-2B instead.


----------



## skwoodwiva

Mad Max said:


> If you end up not liking those LM4562s in place of the Rokit boards' NJM4580s, try TL5580A or ADA4610-2B instead.


I PM'ed you


----------



## Mad Max

Rroff said:


> spoilered for size
> 
> 
> 
> ...


Nice.

I've only dropped 2209 into circuits not made for it have only gotten flabby bass though at least really nice midrange.  My iBasso sounds really damn great, runs two 1611s, without the coloration I've gotten from dropping 1612 and 1611 into random stuff.  This makes me wonder how you are running those opamps in your project.


----------



## skwoodwiva

You freak! Showoff!
Do you know why I really here at all?
See my introduction post.


----------



## Mad Max




----------



## skwoodwiva

Mad Max said:


>


My 2nd Op. You got me... Not the introduction...
https://www.head-fi.org/posts/14124309/


----------



## skwoodwiva (Apr 14, 2018)

Why am I staying here? You & many more...
Here is what my former favorite site thinks
Nons(ci)en(s)e sense. Just as below many like you keep my sharing.
https://forums.audioholics.com/foru...-showing-hearing-acuity-in-1-of-males.110875/


----------



## Mad Max

Yes, we're all crazy here.  

Enjoy your stay.


----------



## Rroff

Mad Max said:


> Nice.
> 
> I've only dropped 2209 into circuits not made for it have only gotten flabby bass though at least really nice midrange.  My iBasso sounds really damn great, runs two 1611s, without the coloration I've gotten from dropping 1612 and 1611 into random stuff.  This makes me wonder how you are running those opamps in your project.



That amp is a variation of the O2 style - fair few differences in terms of capacitors around the opamps though - for instance I swapped out the rail-to-rail 0.22uf film cap for a 10uf Nichicon KZ which in the past has given results I'm personally happier with - which might have implications for the bass performance. As per O2 the buffers sit outside the feedback loop and the volume control sits between the gain and buffers. I've not really noticed any flabbiness to the bass with this setup though I was comparing with LM4562s earlier and noticed some "micro" detail seems a bit recessed on the 2209 in comparison to the 4562s but soundstage is way better on the 2209.


----------



## imran27

Rroff said:


> That amp is a variation of the O2 style - fair few differences in terms of capacitors around the opamps though - for instance I swapped out the rail-to-rail 0.22uf film cap for a 10uf Nichicon KZ which in the past has given results I'm personally happier with - which might have implications for the bass performance. As per O2 the buffers sit outside the feedback loop and the volume control sits between the gain and buffers. I've not really noticed any flabbiness to the bass with this setup though I was comparing with LM4562s earlier and noticed some "micro" detail seems a bit recessed on the 2209 in comparison to the 4562s but soundstage is way better on the 2209.


Exactly.

OPA2209 is very very sensitive and resolving.

On XD-05 it had some distortion in upper highs, they weren't as clean.

Adding bypass capacitors over BUF634 made a huge improvement.


----------



## NymPHONOmaniac

Well, I must admit Im addict to the Burson V5iD Opamp....some pairing are better than other, like this one with a DIY AK4490 DAC-AMP that sound better than my Xduoo XD-05 using same dac....soundstage is just mesmerizing really. And this bass impact...the stock OPamp was NE5532 wich give a way more foward and less well layered sound, now, the V5iD is there to stay!


----------



## NymPHONOmaniac

imran27 said:


> Exactly.
> 
> OPA2209 is very very sensitive and resolving.
> 
> ...



Hi, what is your favorite Opamp with the XD-05? I search one that can give more clarity and details...


----------



## imran27

Nymphonomaniac said:


> Hi, what is your favorite Opamp with the XD-05? I search one that can give more clarity and details...


I have been told of varied reports on different XD-05 units. My friend bought one from Jaben SG and had horrible results with OPA1692.

I on the other hand had amazing results with OPA1692 and that is my favourite.

When it comes to details and clarity:
- OPA1692
- OPA2209
- LME49720 (Needs to be bypassed for satisfactory performance)

After using OPA2209 and OPA1692 all other opamps sound like they're missing a lot of details.

OPA2192 is a close second, it is smooth and has slightly laid backhighs and a subtle mid-bass~lower-mids emphasis and is comparitively forgiving.

After all this comes OPA1612 which is stock in XD-05. It is decent. Everything besides these are pretty bad in my personal opinion, it includes: OPA1652, OPA2197, OPA1602, OPA1662

I have my eyes on OPA1688, OPA2189 (Or 2x OPA189) and Sparkos SS3602 (this one has been extremely praised by a lot of my pals)


----------



## NymPHONOmaniac

imran27 said:


> I have been told of varied reports on different XD-05 units. My friend bought one from Jaben SG and had horrible results with OPA1692.
> 
> I on the other hand had amazing results with OPA1692 and that is my favourite.
> 
> ...



Okay thanks, I will take note this time....did you know a store that do not charge like 15$ for shipping little Opamp?

True, the stock Opamp of XD05 isnt bad at all, sometime I even wonder if I prefer it to the V5iD....

i would like to find a trustable seller on ebay....I use paypal and like free shipping.


----------



## imran27

Normally digikey will provide free shipping for orders over certain minimum value. I don't if that applies for Canada or not. You'll have to check it out for yourselves


----------



## NymPHONOmaniac

imran27 said:


> Normally digikey will provide free shipping for orders over certain minimum value. I don't if that applies for Canada or not. You'll have to check it out for yourselves


Nope man....I need to spend 100$ of Opamp to get free shipping....wanna try the one you suggest but it will make like...20$. Anyway, I will search more...even if ebay and aliexpress make me paranoid about fake OPamp. Thanks for the help.


----------



## skwoodwiva (Apr 16, 2018)

Nymphonomaniac said:


> Okay thanks, I will take note this time....did you know a store that do not charge like 15$ for shipping little Opamp?
> 
> True, the stock Opamp of XD05 isnt bad at all, sometime I even wonder if I prefer it to the V5iD....
> 
> i would like to find a trustable seller on ebay....I use paypal and like free shipping.


Man all this voodoo chatter, where are the science cops????
Lol. Have I been lost in space...

Hey seriously is there a buf 634-like mosfet?
Opamp? I love (mos)fets. I had a sample it blew me away.

Also my  krk vxt6 project, if I go balanced, is the balaclnced architecture maintained throughout?
 What kind of bypassing are you all talking about for the sensitive opamps?


----------



## FritzS

imran27 said:


> I have been told of varied reports on different XD-05 units. My friend bought one from Jaben SG and had horrible results with OPA1692.
> 
> I on the other hand had amazing results with OPA1692 and that is my favourite.
> 
> ...



Gives there any type which are similar to OPA1692 but single channel? 

dual ............. single channel
OPA2209 --> OPA209
OPA1692 -->  ?


----------



## imran27

skwoodwiva said:


> Man all this voodoo chatter, where are the science cops????
> Lol. Have I been lost in space...
> 
> Hey seriously is there a buf 634-like mosfet?
> ...


BUF634 is the output stage aka buffer/output buffer aka current driver

LME49600 is another of such device.

Yes, most probably balanced will be maintained from DAC output to BAL out unless you have a BAL to SE conversion stage but that will be in parallel to the BAL stage

Sensitive opamps need extra supply bypassing. Bypass V+ and V- using capacitor. A 0.1nF ceramic to be bare minimum.


----------



## FritzS

*BUF634* looks like Walt Jungs *'Diamond Buffer'*
http://www.ti.com/lit/ds/symlink/buf634.pdf  see page 10

Walt Jungs *Diamond Buffer*:
http://waltjung.org/PDFs/Op_Amp_Audio_Buffers_1_ED_090198.pdf
http://www.waltjung.org/PDFs/WTnT_Op_Amp_Audio_2.pdf


----------



## skwoodwiva (Apr 16, 2018)

My KRK project https://www.head-fi.org/search/8582304/?q=*&t=post&o=date&c[thread]=876953

I still have to digest the rane document...
 I could be on the best path? I am not sure.
I ask because an opamp may be a better / latter option...


----------



## Rroff (Apr 16, 2018)

imran27 said:


> Sensitive opamps need extra supply bypassing. Bypass V+ and V- using capacitor. A 0.1nF ceramic to be bare minimum.



Yeah - I've found 0.1uf WIMAs to work well for rail-to-ground - they seem to be high speed enough without having to go to ceramics - rail-to-rail bypassing seems to be a bit complicated one and beyond my knowledge really - I've found I can get good results simply by sticking a high quality 10uf aluminium electrolytic close to the opamps power pins but some people have different opinions on that - I know a lot prefer a film cap in that position.

It is also worth in some cases having a LPF on the source input (even just a RC filter) close to the opamp pin - I've found a few opamps people complain about "sounding" grungy or flabby I've no problem when used with that in the equation.

If the opamp is unity gain stable and/or used in some transimpedance configurations having a compensation capacitor in the feedback loop can vastly improve things - can also be done with some opamps that aren't unity gain stable but beyond the scope of my knowledge really.

For some reason I'm not a fan of discrete and/or BUF634 buffers - purely subjective - LME49600 isn't a bad option but can be a bit fussy about the output unless you have the knowledge to properly shunt it when required, etc. :s personally prefer to parallel opamps for buffers - especially as that can allow for stable low impedance output - but even there it isn't a straightforward story with a very limited selection of opamps that can really drive decent current amounts and a couple of them lacking when it comes to things like handling output shorts.


----------



## NymPHONOmaniac

So I pass like....too much hours on ebay trying to figure out wich seller is trustable cause some price for Opamp are just so low its non sens, as well, the look isn't the same so I try 2 different sellers to test their stuffs. One look more trustable than the other and don't receive comment about fake products like lot of others. H'es call xianyeji2016. I buy Muses8820 from him and the LME97720, Both sell at list price but with free shipping.

Other strange one is a dual to mono OPA627AU.

Must begin with something....we learn from error. 
Will share impressions once I got these cause I feel Opamp searcher need reliable Ebay (or aliexpress) seller....Headfi hasn't been any help for me in this aspect. And i'm certain not ALL chinese sellers are full of BS.


----------



## Mad Max

I did not know until now that OPA1688 is a rebranded OPA2172.
1688 apparently has better channel separation above 100Hz and better PSRR/CMRR.  Looks more like an upgraded version to me that way.
Sweet.


----------



## Rroff

Mad Max said:


> I did not know until now that OPA1688 is a rebranded OPA2172.
> 1688 apparently has better channel separation above 100Hz and better PSRR/CMRR.  Looks more like an upgraded version to me that way.
> Sweet.



I wish there was more information out there on opamp lines, etc. a lot of the OPA16xx family seem closely related to various OPA2xxx family opamps i.e. the OPA1612 is basically the same as the OPA2211 except the 2211 is laser trimmed or something for better DC performance while the OPA2209 seems to share a lot with the OPA1602 (and OPA2211) in terms of sound "signature" and doesn't have "SoundPlus" but sounds more refined and doesn't have the slight articulation problem the 1602 has.


----------



## Mad Max

OPA1602 is a bipolar input opamp, unlike OPA2209 as far as I know.  I do find both pretty different.  Now I've got to give 1602 a shot again with that "slight articulation problem" comment.  Haven't touched it in quite some time


----------



## imran27

Mad Max said:


> OPA1602 is a bipolar input opamp, unlike OPA2209 as far as I know.  I do find both pretty different.  Now I've got to give 1602 a shot again with that "slight articulation problem" comment.  Haven't touched it in quite some time


OPA2209 is bipolar.

The only problem I have with OPA2209 is that it is too damn sensitive. It needs a good decoupling to perform at its best.

Another problem is that it's inverting input is slower than its non inverting input (look at large signal responses of both configurations). Which means I would not want to use them in any case where both the inputs are being used like a differential amplifier or summer stage or in some DAC differential amp and I/V are combined (Burson Play for example) so there too I wouldn't use OPA2209 because different speeds of both I puts.

It is however amazing when it is used only in non inverting configuration.

Just yesterday I got my batch of OPA1692. I bypassed my output buffers with Nichicon VZ and damn, this is the kind of sound that's deceptively good. Deceptive because in the first listen you'd be damn sure that OPA2209 is more extended with better tonal balance. But give it some time and you realize that Opa1692 is so clean and has such a dark background that without that brightness and lushness in the background compared to opa2209 you feel it is less detailed. In fact Opa1692 is the most detailed I've heard.

I hope my Play arrives soon so I can 'Play' with it


----------



## Rroff (Apr 19, 2018)

Mad Max said:


> OPA1602 is a bipolar input opamp, unlike OPA2209 as far as I know.  I do find both pretty different.  Now I've got to give 1602 a shot again with that "slight articulation problem" comment.  Haven't touched it in quite some time



As imran27 says they are both bipolar - 1602 articulation problem is pretty subtle but once you notice it you can't "un-notice" it - shame in a way but the OPA2209 has completely replaced them for me as it similarly has a bit of a textured reference like sound but doesn't have the issues the 1602 has.


----------



## Mad Max (Apr 21, 2018)

I hear the articulation funkiness in 1602 in my O2 (2068's position).
Oh wow.
My OPA2209 (or rather, 2x 209 on a dual dip adapter) doesn't physically fit in there, LOL!
TL5580 doesn't like the O2.  Ends up with an awfully white background.  Oh well.
ADA4075 rules.  About as good as 1688, but more relaxed.  A little less thick, but a pinch more resolving, everything is a bit more resolving with it.
Didn't think that I'd switch out after trying 1688.

Maybe it is a good thing that I went for the regular Teac HP50 (with OPA1652 in DAC LPF) instead of the special edition (with OPA1602 in DAC LPF). hahaha

On a side note, what's the deal with 4075's output impedance curve in the low frequencies?  Funky-looking.


----------



## raoultrifan

Mad Max, were you using the OPA1688 and TL5580 in the output stage, by swapping the 2 x NJM4556? If so, did you happen to have some measurements for the output-DC, max. output-voltage before clipping (for 32-ohms and 600-ohms) or anything like it, please?

BTW, the only op-amp I've tested in O2's voltage-amplification-stage with a lower background noise than the default NJM2068 was OPA1652, so I kinda recommend it: https://www.head-fi.org/threads/obj...mpressions-thread.704804/page-5#post-14081180.


----------



## imran27 (Apr 22, 2018)

raoultrifan said:


> Mad Max, were you using the OPA1688 and TL5580 in the output stage, by swapping the 2 x NJM4556? If so, did you happen to have some measurements for the output-DC, max. output-voltage before clipping (for 32-ohms and 600-ohms) or anything like it, please?
> 
> BTW, the only op-amp I've tested in O2's voltage-amplification-stage with a lower background noise than the default NJM2068 was OPA1652, so I kinda recommend it: https://www.head-fi.org/threads/obj...mpressions-thread.704804/page-5#post-14081180.


OPA1652 is very slow.

Btw, can you describe OPA1688 I'm comparison to OPA1692/OPA2209/OPA2192?


----------



## Rroff

OPA1612 works very nicely in the O2 (input stage) - while its tough to beat the on paper figures for the stock configuration subjectively I don't like the stock opamps - the 4556 does very well with actual current hungry headphones but I wasn't happy with it with my Sennheiser HD600s - never seemed to quite get the best out of the drivers - I blame the slew rate which I think is actually in use a bit slower than the "typical" figure in the datasheet but I can't back that up at this time - even just swapping them out for the RC4580 did better though sounds quite "raw" (which probably means they are actually fairly transparent).

I should quit being lazy and break out the oscilloscope sometime but I've only fairly basic understanding on how to use it for audio testing.


----------



## raoultrifan

As long as an op-amp is able to reproduce with flat response entire audio spectrum I would not speak about speed, as a faster op-amp is not helping the O2 at all. Based on http://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php, a 1V/us op-amp is able to deliver 20-20.000 Hz bandwidth with an output of 7.3V, so the 3V/us of the NJM4556 should suffice, honestly.


----------



## Mad Max

raoultrifan said:


> Mad Max, were you using the OPA1688 and TL5580 in the output stage, by swapping the 2 x NJM4556? If so, did you happen to have some measurements for the output-DC, max. output-voltage before clipping (for 32-ohms and 600-ohms) or anything like it, please?
> 
> BTW, the only op-amp I've tested in O2's voltage-amplification-stage with a lower background noise than the default NJM2068 was OPA1652, so I kinda recommend it: https://www.head-fi.org/threads/obj...mpressions-thread.704804/page-5#post-14081180.


I'm sticking with ADA4610 in 4556's place for now.
DC is less than 1mv at the O2's ouputs no matter what I put in, then again, I have those DC-blocking caps shorted for now until I may need them. Before doing that last bit some time back, I think that I had observed that the -3mv offset in stock configuration or so was really a 2068 thing, and swapping opamps would lower the offset.
I have not checked for clipping. I'll do that.


----------



## Rroff (Apr 22, 2018)

raoultrifan said:


> As long as an op-amp is able to reproduce with flat response entire audio spectrum I would not speak about speed, as a faster op-amp is not helping the O2 at all. Based on http://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php, a 1V/us op-amp is able to deliver 20-20.000 Hz bandwidth with an output of 7.3V, so the 3V/us of the NJM4556 should suffice, honestly.



So people say, many far more experienced than myself - but I can't help but notice that playing with the buffers on the O2 with my HD600s slower slew rate opamps (somewhere around 2-3uv/s or lower) don't seem to bring them to life, while anything that is a little bit above that do for whatever the actual reasoning is.

I don't really notice it with other headphones but the HD600s its quite noticeable as the bass and treble seem to "collapse" for want of a better way to put it.


----------



## imran27

raoultrifan said:


> As long as an op-amp is able to reproduce with flat response entire audio spectrum I would not speak about speed, as a faster op-amp is not helping the O2 at all. Based on http://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php, a 1V/us op-amp is able to deliver 20-20.000 Hz bandwidth with an output of 7.3V, so the 3V/us of the NJM4556 should suffice, honestly.


Large signal step response is very important.

High cmrr/Aol with a low settling time and overshoot sound best.

But that will also highly depend on the configuration. If opamp is driving headphones directly it would be different.

In buffered amps, better large signal response should be sought after.


----------



## raoultrifan

Mad Max said:


> I'm sticking with ADA4610 in 4556's place for now.
> DC is less than 1mv at the O2's ouputs no matter what I put in, then again, I have those DC-blocking caps shorted for now until I may need them. Before doing that last bit some time back, I think that I had observed that the -3mv offset in stock configuration or so was really a 2068 thing, and swapping opamps would lower the offset.
> I have not checked for clipping. I'll do that.



Good to know there's another op-amp that works well in the output buffer, thank you! If you find a scope to see when the output waveform starts distorting or clipping it would be awesome. Also, few volts of square-wave might help in seeing how fast is the amplifier with these buffers.


----------



## raoultrifan

Rroff said:


> So people say, many far more experienced than myself - but I can't help but notice that playing with the buffers on the O2 with my HD600s slower slew rate opamps (somewhere around 2-3uv/s or lower) don't seem to bring them to life, while anything that is a little bit above that do for whatever the actual reasoning is.
> 
> I don't really notice it with other headphones but the HD600s its quite noticeable as the bass and treble seem to "collapse" for want of a better way to put it.



It would be awesome to correlate the output op-amp used with a scope and sine-waves and square-waves, so we can better understand what's changing the sound. Under no circumstances the sound gets modified without being able to measure this, although we might need expensive AP equipment to prove that, not just a simple plain scope.


----------



## deafmutelame

I have found this valuable information.

According to Skyward @ gamezone24:
http://www.gamezone24.net/forums/showthread.php?28773-Audio-The-OP-Amps-thread!-(for-advanced-users)

"As I am using an Asus Xonar Essence sound card, i'm gonna take it as example: old Asus Essence devices used crappy OP amps, so in order to improve the sound you will have to replace all of these.
Their latest product brings two *Muses 8920* and one *Muses 8820*. In the package they include 3 exchangable op amps: x2 *LME 49720* and x1 *Muses 8820*. All you have to do is to take off the *Muses 8820* from the Buffer and place a *LME 49720* instead.

*Muses 8820*: The dark beast! Commercially speaking it sounds great because there's the name Muses on it, and they're well known for their Muses 01 which are certainly the most renowned op amps actually on the market. However, they are very crappy and you must take these off and use better ones!

*Muses 8920*: The best one, why? because it's specs are very close from the Muses 01 and it costs only 17€ instead of 75! It's pratically the same as the LME 49720 but the sound rendering is more like what tube amplifiers provides (J-FET technology) so that makes it a bit better than the LME 49720.

*LME 49720:* Well as I explained above, it's more like the same as the Muses 8920, slightly less good since it uses bi-polar technology. But it remains a sure value.

*Muses 02*: Don't get fooled! Its name would make you believe it's right behind the Muses 01, but that's not the case! That thing is not worth better than the crappy Muses 8820. And it's 50€ one!

*Muses 01*: The reference, the legend. Renowned by every audiophile, those amps belongs to the best actually comercialized on the market. It's 75+€ one.

Beware! Yes, some Chinese manufacturers are selling false copies! So watch out if you see, on ebay especially, resellers selling those for 15 bucks only.

There are a lot more models but I don't know them all. Those I listed above belongs to the biggest references and are probably the most used on all "audiophile" devices and materials. There are also some that costs a lot more money, but remember that in the audiophile world, the price doesn't always justify the quality!"

"For anyone using that kind of sound card with 3 double OP amps, i'd recommand to use:


x3 Muses 8920
x2 Muses 8920 (I/V) and x1 LME49720 (Buffer)
x3 LME49720
x2 LME49720 (I/V) and x1 Muses 8920 (Buffer)
x3 Muses 01 (if you got the money)
Any other OP Amps you think would be better than those listed above"



What do you think?


----------



## Mad Max (Apr 22, 2018)

LME49860 >>> LME49720/LM4562
To my ears, at least


----------



## imran27

Rroff said:


> So people say, many far more experienced than myself - but I can't help but notice that playing with the buffers on the O2 with my HD600s slower slew rate opamps (somewhere around 2-3uv/s or lower) don't seem to bring them to life, while anything that is a little bit above that do for whatever the actual reasoning is.
> 
> I don't really notice it with other headphones but the HD600s its quite noticeable as the bass and treble seem to "collapse" for want of a better way to put it.


Slew rate is not speed.

Look at the large signal step response, that is where the attack/decay comes from.

OPA2209 has the fastest attack/decay I have ever heard but those transients are not as clean as on OPA1692. And note that OPA2209 has a slew rate of about 6.4V/uS

Large signal step response for Gain stage and output buffers.

Small signal step response for things like I/V, LP, EQ stage which use low voltage signals.

You will find a lot of consistency when you compare and rate opamps in terms of large signal step response


----------



## raoultrifan

Mad Max said:


> LME49860 >>> LME49720/LM4562
> To my ears, at least



I've tested LME49860 in voltage amplification stage of O2 and Matrix HPA-3B and the noise was quite high, higher than LME49720 (I know, specs are identical, just wider voltage range), higher than MUSES8820 and 8920 etc. Hence, I see no reason of using LME49860 unless you really need higher voltages like +/-22V.


----------



## raoultrifan

deafmutelame said:


> I have found this valuable information.
> 
> According to Skyward @ gamezone24:
> http://www.gamezone24.net/forums/showthread.php?28773-Audio-The-OP-Amps-thread!-(for-advanced-users)
> ...



I really think MUSES8820 and MUSES8920 are very good op-amps and 8920 in I/V should be a very good choice. Also, 8820 in Low-Pass and output buffer should be fine for most configurations, though in my O2 I'm using 8920 with success (lower DC-output and good enough output voltage).

However, without testing with a scope and wave test signals the device you want to roll op-amps in, I can't recommend one op-amp vs. another.


----------



## raoultrifan

imran27 said:


> Slew rate is not speed.
> 
> Look at the large signal step response, that is where the attack/decay comes from.
> 
> [...]



I know, but in a previous post we spoke about the O2 and NJM4556A I guess and per O2's creator this "slow" op-amp is able to rise a 10kHz square signal with12.65 volts in 3.51 uS, so this means a slew rate of 3.6 V/uS; basically V/uS is what defines the ability of an op-amps to rise or fall a signal.

What indeed can change the "flavor" of an op-amp used in output buffer would be the pre and post ringing and usually faster op-amps might have trouble with some capacitive longer cables of the headphones. However, this is something that can be checked with a scope with a resistive load in parallel with a small non-polarized cap. Some people do prefer the sound that has lot of pre/port ringing because this creates sort of a better soundstage under some circumstances.


----------



## imran27

raoultrifan said:


> I know, but in a previous post we spoke about the O2 and NJM4556A I guess and per O2's creator this "slow" op-amp is able to rise a 10kHz square signal with12.65 volts in 3.51 uS, so this means a slew rate of 3.6 V/uS; basically V/uS is what defines the ability of an op-amps to rise or fall a signal.
> 
> What indeed can change the "flavor" of an op-amp used in output buffer would be the pre and post ringing and usually faster op-amps might have trouble with some capacitive longer cables of the headphones. However, this is something that can be checked with a scope with a resistive load in parallel with a small non-polarized cap. Some people do prefer the sound that has lot of pre/port ringing because this creates sort of a better soundstage under some circumstances.


No no.

I am not talking about slew rate at all.

I am talking about large signal step response.

OPA1652 has a slew rate of 10V/uS and OPA2209 has a slew rate of 6.4 V/uS

But look at the large signal step response, OPA2209 is faster by a factor of more than 2. Rise time is ~0.4us for OPA2209 vs ~1us for OPA1652 even though OPA1652 has a higher slew rate.

Pick any opamp which has comparable CMRR (to any reference opamps for comparison) but a lower rise time, faster settling time and low overshoot. You will consistently see that it has higher fidelity, especially with IEMs.


----------



## raoultrifan

I understand, but OPA1652 is able to rise a 10V square signal in less than 1uS, so that means is able to reproduce a 1MHz signal properly: https://www.edn.com/electronics-blo...-The-bandwidth-of-a-signal-from-its-rise-time.

I still think the pre and post ringing makes more of a difference of the output sound, also the harmonics higher than -90dB (again scope and FFT analyzer tests need to be conducted).


----------



## Rroff

raoultrifan said:


> usually faster op-amps might have trouble with some capacitive longer cables of the headphones.



That is a good point actually - I'd not thought about cable length, though the Sennheiser ones are pretty decent - my HD600s normal stereo cable (I've a shorter one for balanced use) is the 3m one - all my other headphones are "normal" length around 1m - its possible the cable length is upsetting certain opamps (some are more susceptible to it irrespective of speed depending on the design goals) and a rough correlation with the slew rates is just coincidence maybe.


----------



## SpudHarris

Ordered a few adapters and Opamps (OPA1652, 1692, 2172 and LME49723) but thought I would rekindle my liking of the ADA4610-2 and think it could be a late night. I completely forgot how great this is... To be truthful I think I only ever tested previously in mobile applications but did rate it then. Now I have the Lycan test bench to test with full sized phone I am appreciating it more. 

I know this was/is a favourite of Mad Max, I haven't used any caps on this yet so potentially more to be had in terms of performance.


----------



## Mad Max

Still is a fave.


----------



## imran27

SpudHarris said:


> Ordered a few adapters and Opamps (OPA1652, 1692, 2172 and LME49723) but thought I would rekindle my liking of the ADA4610-2 and think it could be a late night. I completely forgot how great this is... To be truthful I think I only ever tested previously in mobile applications but did rate it then. Now I have the Lycan test bench to test with full sized phone I am appreciating it more.
> 
> I know this was/is a favourite of Mad Max, I haven't used any caps on this yet so potentially more to be had in terms of performance.


Interesting.

I have some sort of voodoo or bad omen one me whenit comes to OPA1642 and ADA4610-2

I ordered them twice, multiple pieces, soldered them and all of them didn't work. I tried different boards, different soldering temperatures, let them cool for quite some time, no luck.

Maybe I will order them again and try. ADA4610-2 at least looks quite interesting, Aol is low, CMRR is decent, step response in particular looks very promising. I believe it sounds very resolving and detailed with a good amount of air and silence between instruments?


----------



## Mad Max

It indeed does in whatever I use it in as buffer.


----------



## SpudHarris (Apr 26, 2018)

OPA1692, 1652 and 2172 plus LME49723 all arrived today.

1692 and 2172 are VSSOP, oh lordy how the hell to peeps solder them? They are tiny!  I'm ok with SOIC but now and again make mistakes. Anyone on here have any advice or tips?

I can't do anything with them yet as the adapters are on route and I will do some research but please chime in if you can...

Thanks in advance.


----------



## Rroff (Apr 26, 2018)

To solder anything that small I usually use a tiny bit of either silicone PCB glue (make sure its non-acidic/not plumbing stuff, etc. which will corrode electronics over time) or failing that superglue to hold the part in place rather than try and hold it by soldering one pin initially. The rest is just practise and steady hands really :| you can get adaptors that are slightly channelled and solder plated so you just heat the contacts but they tend to be 10-100x the price of normal adaptors.

Having some flux paste (the gel kind) makes it a lot easier to not accidentally bridge pins - I won't even attempt anything below SOIC without some.

Having the right soldering iron bit helps a lot as well - ideally a tapered point that is at most 1mm - ideally slightly smaller than that.

Could try drag soldering but I find that only really works with like SSOP-28 chips, etc.


----------



## dumbears

I received OPA1692 today, and I was eager to solder them to the adapter boards right away.  However, I failed.  I fried 3 of them, and I don't know why.  Everything looked right in appearance, but when they put into test, there's a lot of background noise.  One of them even got heated up and ended with nothing just noise.  Before I put them to test, I checked the connectivity of each pin to the SSOP to DIP adapter board.

I know there're many of you being much more experience, please advise what can possibly went wrong.  My solder is too hot?  I tried 3 temperatures: 300C, 250C and 230C, according to the thermostat.  I have soldered tens of SOIC with only 3 failures (if my memory serves me), but this is the first time I dealed with SSOP.

Pls help.  Thanks in advance.


----------



## Rroff (Apr 26, 2018)

I usually solder at 350C and try to be fairly quick and precise. Pretty low failure rate.

I've grabbed some OPA1692s but in the middle of some house renovations at the moment so probably won't get to trying to solder them before Monday at the earliest.

With SSOP especially if you don't use flux paste it is very easy to accidentally bridge pins and not necessarily be easily noticeable if its pushed up against the housing of the IC.


----------



## skwoodwiva

I am ready to order chips. 

Can you guys ID the op  amps here? 

I assume they can be bettered 

My "dealers trash" brand new batch of 6 Meizu sp 6s


----------



## SpudHarris

dumbears said:


> I received OPA1692 today, and I was eager to solder them to the adapter boards right away.  However, I failed.  I fried 3 of them, and I don't know why.  Everything looked right in appearance, but when they put into test, there's a lot of background noise.  One of them even got heated up and ended with nothing just noise.  Before I put them to test, I checked the connectivity of each pin to the SSOP to DIP adapter board.
> 
> I know there're many of you being much more experience, please advise what can possibly went wrong.  My solder is too hot?  I tried 3 temperatures: 300C, 250C and 230C, according to the thermostat.  I have soldered tens of SOIC with only 3 failures (if my memory serves me), but this is the first time I dealed with SSOP.
> 
> Pls help.  Thanks in advance.



Is it possible you blew them handling them? 

Are your Opa1692 SSOP or VSSOP?


----------



## dumbears

SpudHarris said:


> Is it possible you blew them handling them?
> 
> Are your Opa1692 SSOP or VSSOP?



Thanks foe the reply.  Oops! You're right.  It's actually VSSOP.

I don't know.  I store my soldering iron and other equipment in a tin box, so to kind of decharging myself.  I put the opamp in a tin can too after opening it out from the package.  It's too small, so need tweeters to handle it.  I don't think I over heated the chip since I used flux to solder the pins.  It just needs a quick slide of the iron to solder each side.

I still got 2 left though.  However, I might kill them as well, since I haven't had a clue what I did wrong.  Perhaps, I should let things rest for a couple of days before my next trial.


----------



## imran27

dumbears said:


> Thanks foe the reply.  Oops! You're right.  It's actually VSSOP.
> 
> I don't know.  I store my soldering iron and other equipment in a tin box, so to kind of decharging myself.  I put the opamp in a tin can too after opening it out from the package.  It's too small, so need tweeters to handle it.  I don't think I over heated the chip since I used flux to solder the pins.  It just needs a quick slide of the iron to solder each side.
> 
> I still got 2 left though.  However, I might kill them as well, since I haven't had a clue what I did wrong.  Perhaps, I should let things rest for a couple of days before my next trial.


Once you have enough flux (not a lot), and right amount of solder on your tip (if it is more than what's required, you'll have a hard time resolving the solder bridges) it is pretty quick.

You do need tweezers to handle these tiny parts.

I too destroyed one of mine due to not enough flux and solder bridges. Will try to remove bridges and see if it still works.


----------



## Mad Max

I destroyed a DAC chip that I was replacing once with similarly-sized pins.  Dammit.

But I've been successful with MSOP chips with the help of excess flux paste and a smaller tip on my Hakko 936.  Like it has been said around the web, flux is the "secret sauce" to good soldering, and especially SMD soldering.
I dare not live without it.

Working quickly is good, yes, but I prefer to take my time.  Very quickly solder a pin, blow on the chip to cool it down for several seconds, solder the next pin, cool the chip, and so on and so forth.  No risk of burning the baby that way.


----------



## davveswe

Which opamps can replace mc33078n? I know OPA2134.


----------



## endia (Apr 27, 2018)

i was pretty sure that i can't solder anything smaller than soic8 before watching this video;



beveled tip and dragging technique with some flux paste are working like a magic stick..


----------



## SpudHarris

Yep fried one of my OPA1652 which is SOIC last night so god help me when my VSSOP adapters arrive. Think I need to get some more practice in and maybe a temperature controlled iron...


----------



## raoultrifan

I got no issues with my 4 x OPA1652 op-amp and I’ve used regular DIP8 sockets, not PCB adapters.

Take care, these op-amps could make a difference when used in voltage-gain or output buffers, depends on surrounding components and schematic.


----------



## pelopidas

I've been lurking for a while and decided to try the OPA2209. Damn! These are seriously good opamps. They absolutely blow the LME49990 away. I used the song "Within" from Daft Punk to AB compare and without a doubt the 49990 sounds like it has a grey hole in the soundfield compared to the 2209. I thought I was done with the opamp rolling since moving to Burson V5 and Sparkos 3306. After those two I felt that all other opamps just left me feeling somewhat bored when listening to my music. Once you have that level of detail, attack and decay it is hard to go back to the dull, harsh, hollow, narrow (choose your defect) of regular chip opamps. 
Imran27 got me excited for the first time in over a year about opamps again, Thank you! Now I'm wondering, how many of you have AB compared the OPA1692 to the 2209? Anyone else have a review of them?


----------



## imran27 (Apr 28, 2018)

pelopidas said:


> I've been lurking for a while and decided to try the OPA2209. Damn! These are seriously good opamps. They absolutely blow the LME49990 away. I used the song "Within" from Daft Punk to AB compare and without a doubt the 49990 sounds like it has a grey hole in the soundfield compared to the 2209. I thought I was done with the opamp rolling since moving to Burson V5 and Sparkos 3306. After those two I felt that all other opamps just left me feeling somewhat bored when listening to my music. Once you have that level of detail, attack and decay it is hard to go back to the dull, harsh, hollow, narrow (choose your defect) of regular chip opamps.
> Imran27 got me excited for the first time in over a year about opamps again, Thank you! Now I'm wondering, how many of you have AB compared the OPA1692 to the 2209? Anyone else have a review of them?


OPA1692: Better level of detail, a hell lot darker background kinda deceptively dark, much cleaner attack and decay. Better rumble in the low end, a shallow/slow roll off in the highs. So comparatively more forgiving than OPA2209 but you'll hear harshness (on bad recordings) if you crank it up.

I had all V6 Vivids in my Burson Play.
Now, OPA1692 in I/V, LME49720 in LP and OPA209 in Gain, blows me away. I'm not using V6V anymlaa.

I'm sure OPA2209 in LP would perform better than LME, just that I don't have it right now.

OPA2209 is very transparent and resolving


----------



## pelopidas

Im feeling a bit intimidated by the VSSOP right now. Thats like trying to solder a sugar ant. Is there a place that sells them pre-mounted on a dip8?


----------



## Rroff

pelopidas said:


> I've been lurking for a while and decided to try the OPA2209. Damn! These are seriously good opamps. They absolutely blow the LME49990 away. I used the song "Within" from Daft Punk to AB compare and without a doubt the 49990 sounds like it has a grey hole in the soundfield compared to the 2209. I thought I was done with the opamp rolling since moving to Burson V5 and Sparkos 3306. After those two I felt that all other opamps just left me feeling somewhat bored when listening to my music. Once you have that level of detail, attack and decay it is hard to go back to the dull, harsh, hollow, narrow (choose your defect) of regular chip opamps.
> Imran27 got me excited for the first time in over a year about opamps again, Thank you! Now I'm wondering, how many of you have AB compared the OPA1692 to the 2209? Anyone else have a review of them?



When I had done a bit more playing around with the OPA2209 I did notice some areas where the LM4562 and LME49xxx had more impact and the OPA2209 sounded a little more dull in those areas - overall though the 2209 has a more natural, wider sound without the brittle hollowness of the LM/LMEs.

That said I was running them directly off an ESS Sabre DAC and I think the LM/LMEs tend to play to the DAC's strengths and offset its weaknesses more while the OPA2209 tends to show up its weaknesses - haven't had time to try them from a wider range of sources.


----------



## imran27

Rroff said:


> When I had done a bit more playing around with the OPA2209 I did notice some areas where the LM4562 and LME49xxx had more impact and the OPA2209 sounded a little more dull in those areas - overall though the 2209 has a more natural, wider sound without the brittle hollowness of the LM/LMEs.
> 
> That said I was running them directly off an ESS Sabre DAC and I think the LM/LMEs tend to play to the DAC's strengths and offset its weaknesses more while the OPA2209 tends to show up its weaknesses - haven't had time to try them from a wider range of sources.


Absolutely
In fact a full OPA2209 configuration 8n Burson Play would be unbearable.

I have to have something to control highs and provide a bit more rumble to low end.


----------



## pelopidas

I am using the 2209 only in the gain stage of my headphone amp. I am using a Xonar dac with Burson V5. This is a pretty magical mix right now. I can see how having only 2209 could be too bright, but right now I am enjoying a level of transparency I have not heard yet. The soundstage is incredibly intimate with voices while also being so deep I have wondered at times if there might be an added level of reverb. But no, its just extending out into space and all instruments are detailed and crisp. I guess now I have to try the 1692 and see what that is all about. Damn, I got sucked into opamp rolling again


----------



## SpudHarris (Apr 29, 2018)

SpudHarris said:


>



Output biased NE5534, oh my!! You need to try this...

Edit: This also works for the current hungry AD744.


----------



## Merlin-PT

dumbears said:


> I received OPA1692 today, and I was eager to solder them to the adapter boards right away.  However, I failed.  I fried 3 of them, and I don't know why.  Everything looked right in appearance, but when they put into test, there's a lot of background noise.  One of them even got heated up and ended with nothing just noise.  Before I put them to test, I checked the connectivity of each pin to the SSOP to DIP adapter board.
> 
> I know there're many of you being much more experience, please advise what can possibly went wrong.  My solder is too hot?  I tried 3 temperatures: 300C, 250C and 230C, according to the thermostat.  I have soldered tens of SOIC with only 3 failures (if my memory serves me), but this is the first time I dealed with SSOP.
> 
> Pls help.  Thanks in advance.



I'm not an expert, this is just my personal experience from this hobby.
Some other chips could be more forgiving, but if an opamp is inserted in the socket the wrong way, in my personal experience it will burn the IC, I did this once by mistake.
Some soldering irons have a lot of AC current on the TIP, it's important to use a wall socket with good earth.
I use 11 Watt ceramic resistance soldering iron with less than a 1mm tip for that kind of work and have another 25 Watt iron for other type of work.
I use ceramic resistance for less inductive current at the iron tip.
For example, I measured aprox. 8V AC in my ceramic irons tip and 50V to 80V AC in my metal resistance irons, so it's important to connect them to earth.
I always use flux and after soldering clean it with alcohol making sure its clean and dry before use.
When it's too small I use magnification lens to inspect the result, to see if there are any bridges.
I have other lens, but recently bought this inexpensive low quality macro lens:
https://www.aliexpress.com/item/60X...o-Camera-Clip-LED-Lenses-For/32705459182.html
This photo is with the lens attached to the mobile phone camera, but I use it detached from the mobile without the clip, you have to put the other side just on top of the contacts to focus:


----------



## skwoodwiva

skwoodwiva said:


> I am ready to order chips.
> 
> Can you guys ID the op  amps here?
> 
> ...


Bump, ehh? 
It is a tough (fortune)  cookie! 
Seems there  is no opamp.


----------



## Rroff (May 1, 2018)

A lot of phones/tablets using ARM Cortex, etc. will have an audio codec such as http://www.everest-semi.com/pdf/ES8316 PB.pdf hanging off the SoC and/or a dedicated micro-headphone driver IC rather than an opamp.


----------



## dumbears

endia said:


>


Wonder how you make those pins that soldered into the adapter board.  Would you mind advising me?  Thanks in advance.


----------



## bsoplinger

dumbears said:


> Wonder how you make those pins that soldered into the adapter board.  Would you mind advising me?  Thanks in advance.


I just used header pins. You want the round style versus the square ones. I wanted something I'd get quickly so I got 10 of these on eBay where 2 would have been plenty

https://www.ebay.com/ulk/itm/192428838816


----------



## endia

dumbears said:


> Wonder how you make those pins that soldered into the adapter board.  Would you mind advising me?  Thanks in advance.



with standard header pins, adapter will have too much height..

instead i'm using these pins;
https://www.aliexpress.com/item/10p...32721243961.html?spm=a2g0s.9042311.0.0.1vYUnW

they have 1.27 mm pitch and you have to pull pins one by one and place onto another 8 pin adapter.. to adjust height i'm using perforated boards but if you use them be careful, solder side should be on the bottom side..
hope this helps, any questions wellcome..


----------



## leeperry

Real men solder VSON  in the dark anyway.


----------



## imran27

Just a couple of days back I received my another order of OPA1692 and LME49720

I was enjoying the 1x OPA1692, 2x LME49720, 2x OPA209 configuration in my Burson Play rev1.1

I figured there is some lousiness in low end which needs to be rectified. The bass notes didn't decay fast enough.

Next config: 1x LME49720, 2x OPA1692, 2x OPA209
This config rectified the issues very very well but the top end became slightly unnatural. Bass impact and speed improved a lot. The decay was quite fast, details had much better separation and were lot cleaner with a darker background.

3xOPA1692, 2x OPA209
This is the config which I am using right now.
Superb in terms of low end performance. Mids are quite natural. But the top end is less natural than any of the previous configs. Best instrument separation I have heard with chip opamps.

3x LME49720, 2x OPA209:
This config gives the most natural tonality. But the technicalities of sound like attack and decay, background/noise floor, etc. are pretty bad. Separation and imaging is bad, layering is bad.
Basically, tonality is all you get with this config.

1x V6 Vivid, 2x OPA1692, 2x OPA209:
This config sounds best of all. Even compared to configs more V6V's, this is the one that has best of everything like tonality, technicalities (attack/decay, extensions, background/noise floor) and presentation (imaging, separation, layering, etc.)
One complain I had with V6V is it is extremely subtle with the low end. That is resolved with OPA1692 in LP. Also, the highs did't seem very revealing and natural. I wanted highs something between OPA1692 and OPA2209. 2x OPA209 in gain stage solved that. Gave me amazing transparency of preceding stages with a good smooth textured mid range and top end, highs especially are pretty forward with OPA209, but OPA1692 has some roll off in the highs with pretty good extension. So overall synergy is perfect.

If I had to give up discrete opamps, OPA1692 is the one I would use for I/V. Best of all I have tried. V6V is better than OPA1692 but OPA1692 isn't extremely far off from V6V and that's bragging rights for OPA1692 considering it's dirt cheap price
For I/V: OPA1692 is best, compared to - OPA1612, OPA2192, OPA2209, OPA1652, NE5532, LME9720, OPA1622, OPA1602, OPA1662
For LP: OPA1692 for now, I have good expectations from OPA2209 but they are out of stock.
For gain: OPA209 but only against NE5534 and V6V singles.

Will be trying these in gain stage: OPA1611, ADA4610-1, OPA189
Will be trying these in LP stage: OPA2209

Any suggestions are always welcome.


----------



## pelopidas

Mouser is out of the 2209 but they are availabe on Digikey last I checked.


----------



## Rroff (May 4, 2018)

imran27 said:


> Just a couple of days back I received my another order of OPA1692 and LME49720
> 
> I was enjoying the 1x OPA1692, 2x LME49720, 2x OPA209 configuration in my Burson Play rev1.1
> 
> ...



If you have one (and it works in that position - needs a gain of 5+ to be stable) I'd be curious what your impression would be of say AD8066 in the gain position into say OPA2209 and 209 - gonna try and test that myself sometime but my current amps are hardwired for 2.5x gain.


----------



## CoiL

Hey, any comments about Burson dual-V5i instead NE5532 @ HO opamp (separate amp board inside) with my Aune T1 ?
Also wondering if it will improve SQ if I use V5i instead DAC opamp OPA2134 ?
I have already upgraded power input filtering caps for Panasonic FR and coupling capacitors for SilmicII. Using Siemens E88CC goldpin tube as buffer.


----------



## dumbears

What are the best opamp you believe for LPF?  What are the requirements for selection?  Pls advise.  Thanks!


----------



## raoultrifan

I got very good results, especially in regard with low-noise, when using AD8599, MUSES8920 and SS V6 Classic.


----------



## LaughMoreDaily

raoultrifan said:


> I got very good results, especially in regard with low-noise, when using AD8599, MUSES8920 and SS V6 Classic.


What are you referring to? Good results for doing what?


----------



## raoultrifan (May 10, 2018)

The above is my answer to "What are the best op-amp you believe for LPF?"

Using these op-amps I got the best SNR (extremely low-noise), lowest THD, very low DC-output voltage and, of course, a perfectly flat bandwidth response (well, even a 5532 has a perfectly flat response) and the most important: no oscillations occurred from 0 to 10 MHz (FFT spectrum is clean).
Tests done with ASUS Essence One MKii and BURSON Play.

L.E.: LM4562 is great op-amp for use in LPF too.


----------



## spacequeen7

Hi everyone ,was wondering if I can get some advice on my newly acquired  ,cheapo SMSL Audio Sap-II Pro,I like to try few op-amps and  pair with Topping D50 (3x OPA1612A )
I have this old timers coming my way (OPA2107,OPA2111 and OPA1612 ) but not sure what's the latest and greatest ,also was wondering if this beauty will work ?
https://www.ebay.com/itm/Sonic-Imag...pAmp-HDAM-DIP8-enhanced-upgrade-/251471560791

she's ready ..


----------



## raoultrifan

TI recommends OPA2134/4134: http://www.ti.com/lit/ds/symlink/tpa6120a2.pdf, so I'm sure this should work very well. I would try AD797 or AD8599 because of the very low-noise feature, but also MUSES8820/8920.

If you do have OPA1612 coming over, then it should work perfectly too.

Not sure why spending on that discreet op-amp almost twice of the entire amplifier. All you need is a wire with gain to pump-up the music into the output stage.


----------



## Rroff

Not a fan of the OPA2134 personally - it is like someone playing (on an instrument) the same tune for the 1000th time - accurate enough but with none of the passion or nuance of the first few times. If I'm in the mood for that so called "burr-brown" slower lazier sound I prefer the OPA2228 but as with my comments about the AD8066 below you can't just drop that into any old circuit and get good results - the OPA2227 is a more drop in replacement but doesn't sound quite the same as the 2228.

OPA1612 is decent the only reason I'd use anything else really is that the 1612 tends to be a tiny bit cold/bright and sometimes a touch synthetic otherwise it produces very high quality and quite pleasing results. I use the AD8066 as an alternative if/when I get bored of the 1612 quite a lot as it has a darker background and decent low end but it isn't a straight drop in for a lot of circuits unless you know the circuit setup.

LM4562 is always worth a try as it produces very high quality results but can be a touch susceptible to being upset by noise, etc. if you like it then it might be worth considering some of the LME4xxxx series.

Personally I don't tend to stray far from what I've mentioned above these day - got some OPA1692 to try but been too busy to spend the time (and considering *****ing out and buying a hot air rework station to solder them as I've too much on my mind to have much patience trying to solder VSSOP with a regular iron right now).


----------



## imran27

Rroff said:


> Not a fan of the OPA2134 personally - it is like someone playing (on an instrument) the same tune for the 1000th time - accurate enough but with none of the passion or nuance of the first few times. If I'm in the mood for that so called "burr-brown" slower lazier sound I prefer the OPA2228 but as with my comments about the AD8066 below you can't just drop that into any old circuit and get good results - the OPA2227 is a more drop in replacement but doesn't sound quite the same as the 2228.
> 
> OPA1612 is decent the only reason I'd use anything else really is that the 1612 tends to be a tiny bit cold/bright and sometimes a touch synthetic otherwise it produces very high quality and quite pleasing results. I use the AD8066 as an alternative if/when I get bored of the 1612 quite a lot as it has a darker background and decent low end but it isn't a straight drop in for a lot of circuits unless you know the circuit setup.
> 
> ...


I agree.
OPA1692 and LME49860 are great.

LME49860 bypassed with a good low esr cap performs amazingly well. If it is not an LPS based circuit you'll get good results using a low esr cap which is designed for switching supplies. Higher value in that particular case would reap noticeable benefits.


----------



## skwoodwiva

Hey, please tell which one is the descrete version? 
How costly is it?


----------



## spacequeen7 (May 11, 2018)

Thanks ,will ad Muses 02 to the list before making some drastic changes to aluminum casing
http://guneytuncer.blogspot.com/2017/07/hangi-op-amp.html
EDIT; BTW amp came in with  Nichicon caps so I don't think I need to swap this


----------



## skwoodwiva

raoultrifan said:


> TI recommends OPA2134/4134: http://www.ti.com/lit/ds/symlink/tpa6120a2.pdf, so I'm sure this should work very well. I would try AD797 or AD8599 because of the very low-noise feature, but also MUSES8820/8920.
> 
> If you do have OPA1612 coming over, then it should work perfectly too.
> 
> Not sure why spending on that discreet op-amp almost twice of the entire amplifier. All you need is a wire with gain to pump-up the music into the output stage.


I, should have  quoted you, is there an op amp that is discrete, I can buy to go in the dip pads?


----------



## raoultrifan

You could probably try the SS V6 Classic from BURSON. I found very pleasant results with this discrete op-amp, especially in regard with soundstage and detailing.


----------



## SpudHarris

Listening to Opa1692 this evening and am liking it a lot. Need to spend some time to fully appreciate but my initial impressions are that it is a contender.

I am proud to say that after investing in the proper tools (variable heat solder iron, flux 'paste', and an illuminated and magnified helping hand) I can now solder VSSOP Opamps. Opa1692 and 2172 both soldered 1st time with no issues... They both live!!

Last week I killed 3 x SOIC Opamps in one night with the kit I had. Cost me about £40 in total to buy the proper stuff which no doubt I will recover in no time in chips I don't fry


----------



## Rroff

Yeah temperature controlled iron makes such a difference - if you are doing much soldering of electronics like this at all it is worth the investment.


----------



## FritzS (May 13, 2018)

off topic

Which cap should be better for AD797 compensation or 'Distortion Cancellation and Bandwidth Enhancement'?
styroflex or glimmer?
I mean the cap for 'Distortion Cancellation and Bandwidth Enhancement' (page 15 of AD797 data sheet).
http://www.analog.com/media/en/technical-documentation/data-sheets/AD797.pdf
https://www.reichelt.at/Styroflexko...wQATcAAILGcqA1413e0824323c480b7ed7dbab74dee6a

PS: A new thread about on diyaudio
http://www.diyaudio.com/forums/chip...ompensation-distortion-cancellation-caps.html


----------



## SpudHarris (May 13, 2018)

ADA4084 anyone? SOT23 unfortunately, from Farnell at least. Will have to look elsewhere.


----------



## imran27

SpudHarris said:


> Listening to Opa1692 this evening and am liking it a lot. Need to spend some time to fully appreciate but my initial impressions are that it is a contender.
> 
> I am proud to say that after investing in the proper tools (variable heat solder iron, flux 'paste', and an illuminated and magnified helping hand) I can now solder VSSOP Opamps. Opa1692 and 2172 both soldered 1st time with no issues... They both live!!
> 
> Last week I killed 3 x SOIC Opamps in one night with the kit I had. Cost me about £40 in total to buy the proper stuff which no doubt I will recover in no time in chips I don't fry


For soldering VSSOP with good consistency I use knife edge tips. Just slide them gracefully starting from pins towards the side which holds solder going all the way towards pins on the other side. Soldering them in this order is safer for avoiding solder bridges. I soldered in reverse order which means after first pin my soldering iron would always be between 2 pins which already have solder resulting in nasty solder bridges.

And yeah, OPA1692 is a superb sounding opamp. I am using it in the LP stage of my Burson Play rev1.1

Bypass it with some good electrolytic caps and you'll see how well they reflect the character of the capacitor.

For example, I tried it with Nichicon PW (I already knew this cap is extremely analytical, provides sound which is extremely extended on both ends and highs get fatiguing at times). And with PW the OPA1692 did sound quite unbearably fatiguing. They have a great synergy with UCC KZE. Haven't tried Nichicon VZ (these are tube'ish sounding).

I love the low end control of OPA1692


----------



## Rroff

imran27 said:


> Bypass it with some good electrolytic caps and you'll see how well they reflect the character of the capacitor.



If I'm reading what you are saying right that would make them a bit interesting with the Nichicon FG which I believe supposedly has a bit of a bump around 500Hz.


----------



## imran27

Rroff said:


> If I'm reading what you are saying right that would make them a bit interesting with the Nichicon FG which I believe supposedly has a bit of a bump around 500Hz.


Haven't tried FG. Only PW and VZ.


----------



## spacequeen7 (May 16, 2018)

Received my first op amp today for sAp II, OPA2107AP ..I'm little speechless and this is only 1 hour of burn in,I actually got 2 more coming from various sources after reading this thread https://www.head-fi.org/threads/opa2107-wow.187020/ ,this one is from Mouser
I was wondering how good this little amp can get ...... getting closer to pulling  the trigger on Sonic Imagery 994Enh or Sparkos Labs SS3601,anyone familiar with both ?
P.S. this amp have peach-black background and it seams like 0 distortion ,little dumbfounded
Cheers


----------



## Rroff (May 16, 2018)

Had a bit of time to solder one of the OPA1692s today - never want to do that with a regular iron again :s as I've only done one so far I've been listening to it using a variety of different other opamps (NJM4556, LM4562, LMH6643, RC4580, OPA2209) as buffers so not a perfect test of it on its own but immediately notice there is a "crunch" to the bass not there with the OPA2209 it is also more "upfront" than the OPA2209 which I've mixed feelings about.

I'll get back with more impressions on it when I've had the time and patience to solder two more for buffers and/or rebuilt my CMOY style test amp.

EDIT: Using the 1692 as the gain stage and 2209 as buffers I actually quite like as it seems to take away a lot of the negatives and reinforce the positives of the two.


----------



## spacequeen7

Found the man behind the Sparkos Labs (lightning fast shipping )


----------



## nesty

I dont know if it is only me but I have Sparkos  SS3602, OPA2209 and OPA1692... and I have AD4084 but have not yet engage it in.

OPA1692, clarity and details which translates to better highs., bass it can go deep but not basshead, width and depth is there, mids are a bit laid back but just right.
OPA2209, better instrument separation than 1692 as I compare this with SS3602,  bass same with 1692, I can say it's identical when it comes to width, depth and soundstage with 1692. The mids are forward but just on point. highs are there not sibilant but 1692 has better clarity.


----------



## davveswe

I have problems with my burson V5i. DC offset is 0.2-0.4V. What causes the high offset? 
My amp uses OPA2134 as standard. 
Tested other opamps and they are okey


----------



## raoultrifan

This DC is pefectly normal for this op-amp, just check it’s datasheet (voltage off-set, then multiply with the gain used).

In what device are you using it and in what stage?


----------



## spacequeen7

made slightly better access ,to bad Sparkos won't cooperate


----------



## DSebastiao

I don't know if this is the appropriate thread, but i stunbled across the CMoy, i like the project and i'm thinking of doing it, i've made some little electrical projects in the past so i'm ok with the schematics, i'll give a better look at the website, but want to ask if there's any other article that i should read? What type of tweaks can be done or what tweaks does the community unanimously recommend?

Also, this is suppose to cost around 20$ right? But how does it compare to other amp's? In what price region would you put it? 

Anyone from europe? Where's the best place to get all the components?


----------



## Rroff (May 21, 2018)

I used Tangentsoft's guides when I first built a CMoy type amp - it is an excellent resource for those with basic electronics experience wanting to get a handle on the audio side of it.

The tweaks are almost endless from different types and configurations of capacitors, expanding on the basic gain stage with various current buffers and so on. I completely changed the power supply section using a DC-DC convertor to generate a negative rail instead of a virtual ground and then added regulators to clean it all up. You can also implement things like low pass filters on the signal input to give the amp better resilience against EMI/RF, etc. as well.

To be frank while you can build it for "$20" I wouldn't approach it as a way to save money on an amp and to get the best results you are going to be looking at more like double that. With a few simple tweaks you can get very good results from a CMoy type circuit if the layout is reasonably good.

I use Farnell and Mouser a fair bit but also have a fairly well equipped local indy which can be useful.


----------



## spacequeen7

Received Burson dual V5i today ...next level in comparison to :
Second best synergy -OPA2111KP 
OPA2134PA 
OPA2107 
MUSES8820 
OPA1612AID
LME49860NA 
OPA2604 

Sparcos SS3602 (incompatibility-two tested )


----------



## SpudHarris

49880 anyone??


----------



## imran27

SpudHarris said:


> 49880 anyone??


Damn, I was just wondering about it a week ago. I saw these on Element14. Technically they measure worse.

Anyways, my next investment would be in OPA1652 and probably ADA4610-1/-2 (this I am really hopeful for)


----------



## pelopidas

My SSOP boards finally came yesterday and I soldered up some 1692. I used an aligator clip to hold the chip in place and that made soldering pretty simple. I got a q-tip and put a drop of water on the chip to keep it from overheating and used plenty of flux. I was a bit worried but none of them died.   
Sonically the 1692 is very similar to the 2209. Very resolving and detailed with good imaging. However, it also sounds like it has a certain sheen or gloss on it. Not at all unpleasant. It reminds me of bypassing my power caps with teflon. The problem I do have is that it has a relatively high offset. I have not been able to tame that in my headphone amp. The best I could do is around 50mv which makes me really uneasy when plugging in expensive headphones. Some of the chips were in the 100+ mv offset. They are not damaged and sound great in my DAC where that does not matter. Anyone wanting to use these in a CMOY though should be very careful to measure the offset before just running with them. The same goes for the Burson V5i. Those have crazy offset. 
On a different note, I decided to relisten to some old favorites to see how they compare to the 2209 and the 1692.  LME49990 used to be a safe go to. Now it sounds dull and undynamic and with a white glow, much like a silver mica capacitor produces. The 797BRZ is a muddy mess. I was actually very surprised at how poorly it competes with the 2209. the 797 is still populating my HTPC Xonar, however, I just ordered a bunch of 2209 and 1692 to replace those. The LME49860 did put up a good showing. It does not have the incredible clarity and detail of the 2209 but it also was not muddy, confused or plagued with some other disqualifying characteristic. 

So Spud, what about the 49880? Don't keep us in suspense


----------



## FritzS

Which real buffer ICs (gain 1) are now available?

I know about:
BUF634, LH0002 (old, the first on market?), LMH6321, LME49600, LME49610, LT1010, ......

PS: Under real buffer I mean ICs similar to the  „Diamond Buffer“ design from Walt Jung
http://waltjung.org/PDFs/Op_Amp_Audio_Buffers_1_ED_090198.pdf
http://www.waltjung.org/PDFs/WTnT_Op_Amp_Audio_2.pdf


----------



## raoultrifan

Both BUF634 and LME49600/LM49610 can be used with success. They're extremely low-noise and low-distortion and have a high output power.

Some useful examples would be:
- BUF634 used by Dr. Meier Cords in his amplifiers
- LME49600 used in Benchmark DAC3

I've personally did the TI recommended design with LME49720 and LME49600 and amplifier was measuring very well, also the sound was neutral and powerful enough to drive all of my cans. Also, swapping LME49600 with BUF634 changed nothing in my measurements and hearing, so...maybe internally there's not much of a difference between the too...don't know.


----------



## LaughMoreDaily

toear said:


> Thanks for your suggestions and sharing your most recent experiences.
> 
> I noticed that these ic chips are tiny. My understanding is that I would have to solder them onto some kind adapter so they would work in a dip 8 package?
> 
> ...


Thanks for letting me know these are on Mouser. I couldn't find them.


----------



## toear

LaughMoreDaily said:


> Thanks for letting me know these are on Mouser. I couldn't find them.


----------



## FritzS

raoultrifan said:


> Both BUF634 and LME49600/LM49610 can be used with success. They're extremely low-noise and low-distortion and have a high output power.
> 
> Some useful examples would be:
> - BUF634 used by Dr. Meier Cords in his amplifiers
> - LME49600 used in Benchmark DAC3



Jan Meier use two BUF634 parallel
http://meier-audio.homepage.t-online.de/classic.htm

Thomas Funk use probably LME49600/LME49610 but he don't give hints about.
http://funk-tonstudiotechnik.de/LPA-2S-englisch-300.pdf



> I've personally did the TI recommended design with LME49720 and LME49600 and amplifier was measuring very well, also the sound was neutral and powerful enough to drive all of my cans. Also, swapping LME49600 with BUF634 changed nothing in my measurements and hearing, so...maybe internally there's not much of a difference between the too...don't know.



BUF634 offers in BW mode more quiescent current (about 15 ... 20mA) and running at low volume level in class A.
LME49600/LME49610 offers nearly the same.


----------



## raoultrifan

Thanks for the Funk links, FritzS. Never seen so many measurements for the LME49610, quite an impressive output buffer indeed.

Another proof that higher impedance headphones might do a better pairing with a headphone amplifier than lower impedance ones (A-weighted: 115dB @200-600 Ohms vs. 110dB @32 Ohms, across 20-20.000Hz). Also, Tyll's PDF measurements show a more linear phase for high impedance cans too.


----------



## LaughMoreDaily

What are your favorite opamps for an I/V / DIP-8 configuration (Walnut/Zishan, etc)?

Mine so far are: AD8066AR, BB2107AP, LME49720NA, LT1028CS, OPA627AU


----------



## pelopidas

I think this really depends on what equipment you are using. I have an Asus Xonar and nothing comes close to what Burson V5 can do there. However, in my headphone amp the OPA2209 is the current king. 
What equipment are you running?


----------



## LaughMoreDaily

pelopidas said:


> I think this really depends on what equipment you are using. I have an Asus Xonar and nothing comes close to what Burson V5 can do there. However, in my headphone amp the OPA2209 is the current king.
> What equipment are you running?


I have a Walnut V2S, Zishan Z1 and Z3 and various earbuds, IEM's and headphones including a Superflux 668B. Nothing too expensive, all budget gear.

Which headphone amp are you speaking of?


----------



## SpudHarris

I have one or two Opamps to try but think I have found "The One" in Muses01. I know it's expensive but nothing else gets so much right. My listening sessions are getting longer and longer.

Has anyone tried OPA1622? I've ordered a couple but just wondering if anyone has any experience with them...


----------



## Rroff

SpudHarris said:


> I have one or two Opamps to try but think I have found "The One" in Muses01. I know it's expensive but nothing else gets so much right. My listening sessions are getting longer and longer.
> 
> Has anyone tried OPA1622? I've ordered a couple but just wondering if anyone has any experience with them...



I assume you are aware the 1622 isn't just a drop in like regular opamps? and requires a couple of external components, etc. and being VSON isn't DIYer friendly.

Think we talked about it recently in this thread but I can't recall if you were part of that conversation or not off the top of my head.


----------



## SpudHarris

Yeah, I guessed it was a little different but there is some positive stuff on other forums. This is what I have ordered...


----------



## Rroff

Ah yeah that was what we talked about before - interested in how they perform.


----------



## LaughMoreDaily (May 30, 2018)

Rroff said:


> I assume you are aware the 1622 isn't just a drop in like regular opamps? and requires a couple of external components, etc. and being VSON isn't DIYer friendly.
> 
> Think we talked about it recently in this thread but I can't recall if you were part of that conversation or not off the top of my head.


I bought the same 1622 like SpudHarris I want to put mine in a Zishan/Walnut portable music player. Are you saying I can't use it in those because I need some other parts?

What would I need?


----------



## LaughMoreDaily (May 30, 2018)

SpudHarris said:


> I have one or two Opamps to try but think I have found "The One" in Muses01. I know it's expensive but nothing else gets so much right. My listening sessions are getting longer and longer.


Have you compared the 01 to the 8920? Some people prefer that one and it's only $20 US


----------



## SpudHarris (May 30, 2018)

I did but not for a long time. I will have a listen tonight...


----------



## Rroff

LaughMoreDaily said:


> I bought the same 1622 like SpudHarris I want to put mine in a Zishan/Walnut portable music player. Are you saying I can't use it in those because I need some other parts?
> 
> What would I need?



If you bought the same thing as he has bought then it is already assembled on a breakout board with the additional components - I'm curious how well it works though as I believe the IC requires a ground connection and it seems they've simply used a resistor divider on the board.

The 1622 is more designed to be used as an application specific implementation kind of like the TPA6120 rather than dropped into a circuit designed for an opamp - but it can be made to work in place of a regular dual opamp.


----------



## toear

Hi All

I just swapped a opa2209 into my zishan z2 and the volume has dropped significantly... can anyone tell me what I may have done wrong. I soldered the chip onto a dip8 adapter myself... do I do something wrong?

Everything seems to sound ok ... just waaay lower in volume...

Thanks and much appreciated!


----------



## Rroff

Only thing I can think of is that you've bridged the output and feedback pins resulting in the amp working without gain but a bit weird if you'd managed to do that on both channels.


----------



## toear

Rroff said:


> Only thing I can think of is that you've bridged the output and feedback pins resulting in the amp working without gain but a bit weird if you'd managed to do that on both channels.



To clarify, you mean the solder is running across two pins?

I'm pretty sure its clean, but will double check. I am getting sound from both channels as well...  could it be that I soldered the chip in backward/reversed?

Thanks!


----------



## toear

hmmm... i just reseated the chip again and seem to getting 'full' volume.... perhaps a bad connection.... 

Thanks!


----------



## raoultrifan

SpudHarris said:


> [...]
> 
> Yeah, I guessed it was a little different but there is some positive stuff on other forums. This is what I have ordered...



Nice, could you please indicate the source? eBay perhaps, right?

BTW, from the datasheet I can only see tests/graphs when +/-5V PSU is used, so output voltage is quite low. I was wondering if you could please use this op-amp as output buffer to drive directly the headphones but powere through a PSU of at least +/-12V, if possible. Perhaps into an Objective2 if you have one laying around?

Thank you!


----------



## endia

SpudHarris said:


> Yeah, I guessed it was a little different but there is some positive stuff on other forums. This is what I have ordered...



i have a similar one with additional caps.. installed as lpf on my zishan dsd player but didn't find enough time for critical listening..


----------



## toear (Jun 1, 2018)

Hi all

Hi All

I seem to have a problem. I ordered an opa1692idgkt from Digikey with what I thought was the matching adapter. I thought the opa1692 was a vssop8  but it doesn't fit on the adapter (which is labeled as a vssop8 to dip8 adapter). Is there something else I should be looking at in the ID to match these up?

And... Could anyone tell me which board I need?

Thanks so much!



edited for clarity


----------



## Rroff (Jun 1, 2018)

Looks like VSSOP 0.5mm and I believe the opamp is VSSOP 0.65mm just to be confusing.

I just use the cheapy SOIC/SSOP (dual sided) to DIP8 adaptors you can find on ebay and Amazon, etc. the ones I've got so far have been the right size.


----------



## nesty (Jun 4, 2018)

my opa1692 and opa2209 on lbb4.


----------



## LaughMoreDaily

toear said:


> Thanks for your suggestions and sharing your most recent experiences.
> 
> I noticed that these ic chips are tiny. My understanding is that I would have to solder them onto some kind adapter so they would work in a dip 8 package?
> 
> ...


Do you have the links for those opamps? I will buy them too. Burson is too expensive ($70) for me.


----------



## toear

I got mine here...

https://www.digikey.ca/product-detail/en/texas-instruments/OPA1692IDGKT/296-47619-1-ND/8111116

you need a 0.65mm spacing on the adapter.. not 0.5mm... I learned the hard way... still waiting...


----------



## toear

these adapters...

https://www.ebay.ca/itm/273154946269


----------



## toear

Rroff said:


> Looks like VSSOP 0.5mm and I believe the opamp is VSSOP 0.65mm just to be confusing.
> 
> I just use the cheapy SOIC/SSOP (dual sided) to DIP8 adaptors you can find on ebay and Amazon, etc. the ones I've got so far have been the right size.



Thank you!... (I thought I had posted this earlier but hadn't)... much appreciated!


----------



## LaughMoreDaily (Jun 4, 2018)

toear said:


> I got mine here...
> 
> https://www.digikey.ca/product-detail/en/texas-instruments/OPA1692IDGKT/296-47619-1-ND/8111116
> 
> you need a 0.65mm spacing on the adapter.. not 0.5mm... I learned the hard way... still waiting...


I'm not sure what you mean about the 0.65 mm spacing. I'm just a newb trying to order it for a Z1.

I don't want to solder anything. I have these adapters: https://www.aliexpress.com/item/10P...s-Adaptor-Solder-Type-Socket/32651679826.html

Will they work?


----------



## toear

LaughMoreDaily said:


> I'm not sure what you mean about the 0.65 mm spacing. I'm just a newb trying to order it for a Z1.
> 
> I don't want to solder anything. I have these adapters: https://www.aliexpress.com/item/10P...s-Adaptor-Solder-Type-Socket/32651679826.html
> 
> Will they work?



Those will only work with dip8 configured opamps. Not necessary as the Z1 already has a socket. The opa1692 is a completely different size and footprint. I'm just a newb at this as well... So if I'm wrong someone else please chime in...


----------



## SpudHarris (Jun 6, 2018)

Does anyone know what the "SQ" suffix is about on Analogue Devices?

I was searching for the TO99 version of AD712 and Farnell have this SQ version on their site for circa £33 + VAT. I don't know anything about the SQ but assume it means something like 'Superior Quality'?? Anyone have experience or knowledge of this? I love the 712 but not for that sort of cash unless there is a reason... There are several other AD chips with this suffix on Farnell. Colour me curious...


----------



## LaughMoreDaily

toear said:


> Those will only work with dip8 configured opamps. Not necessary as the Z1 already has a socket.


Do you know what to look for to make sure the opamps are DIP8 when they don't look it? (no long legs) I accidentally bought some SOP-8 opamps am wondering if those would work in the right adapter. It looks like we are both new around here.


----------



## toear

I just look for some kind of description that says they are dip 8 or on dip8 adapters . That and I looked at a lot of op amps. You can usually tell if it's in dip 8 configuration. Sorry to be not more helpful...


----------



## LaughMoreDaily

toear said:


> I just look for some kind of description that says they are dip 8 or on dip8 adapters . That and I looked at a lot of op amps. You can usually tell if it's in dip 8 configuration. Sorry to be not more helpful...


Your right you can tell, it was just a mistake. 

I did buy an opamp today that was only 1 chip, while another seller had a two chip version. Would mine be a dual naturally vs the other sellers 2 chips on one browndog be monos making a dual?


----------



## atmosfearz (Jun 11, 2018)

Hello. Sorry If I missed the correct thread. I've recently ordered my first DAC (AliExpress link). Can you make me an advise: should I change the default 3x NE5532P and which opamps can fit this board?  have nothing to compare with and as I get from old threads something like OPA2604AP, AD825 would be better. This one is fake but seems to be good: Muses8920 link. Thank you.


----------



## raoultrifan

I would provide a good example here for TI DACs: http://nihtila.com/2017/01/08/pcm1794a-output-stage-opamp-measurements-lm4562-ne5532-and-opa2134/
- NE5532 is TI’s recommend opamp for IV
- LM4562 seems to have a bit better SNR than NE5532 when used in LPF

If you really-really want to use other opamps (though I wouldn’t really call it an upgrade) you could use in IV MUSES 01 or 8920 and in LPF BURSON V6 or V5, MUSES 02 or 8820 (in order of prefference).

Also, a very good opamp for use in IV is AD8599; it was used with great success inside many M2Tech DACs.

AD8672 and OPA1612 are also very good opamps for use in LPF.


----------



## nesty

raoultrifan said:


> I would provide a good example here for TI DACs: http://nihtila.com/2017/01/08/pcm1794a-output-stage-opamp-measurements-lm4562-ne5532-and-opa2134/
> - NE5532 is TI’s recommend opamp for IV
> - LM4562 seems to have a bit better SNR than NE5532 when used in LPF
> 
> ...



Which test parameter/s do you look into in choosing AD8672/OPA1612 as good LPF? thanks


----------



## raoultrifan

AD8672 is used in many of the M2Tech DACs (including the high-end Vaughan that has 8xPCM1795 DAC chips inside), also its specs are very good as well for output buffer and LPF as well. However, AD8599 has better specs and in M2Tech Vaughan seems to be used in both I/V and LPF stages: https://durobblog.files.wordpress.com/2013/02/6n.jpg (if I remember well, AD8672 is used in output buffer in this DAC).

OPA1612 is relatively new opamp and is widely used in several medium-priced but also high-priced DACs. This is also AKM's recommended opamp in many AKM DAC's in both IV and LPF stages.

If possible, you could try all of the three op-amps from above without getting worried to get oscillations. Of course, MUSES 8920 in I/V and perhaps LPF, MUSES 8820 in LPF and output buffer could be a safe bet too; these will not oscillate and will work just fine.


----------



## atmosfearz (Jun 12, 2018)

raoultrifan said:


> I would provide a good example here for TI DACs: http://nihtila.com/2017/01/08/pcm1794a-output-stage-opamp-measurements-lm4562-ne5532-and-opa2134/
> - NE5532 is TI’s recommend opamp for IV
> - LM4562 seems to have a bit better SNR than NE5532 when used in LPF
> 
> ...



I've decided to order Muses 8920 from aliexpress because It's really cheap (3x for 12$). I will post a differences with default 5532 when I get it.


----------



## raoultrifan

Most likely not original MUSES on eBay at this price. Here's the correct price: http://www.profusionplc.com/parts/muses8920d - 7 USD each.


----------



## atmosfearz

raoultrifan said:


> Most likely not original MUSES on eBay at this price. Here's the correct price: http://www.profusionplc.com/parts/muses8920d - 7 USD each.


I know (wrote it in upper post), but reviews seems to be ok (>100 orders). I'll try and tell you how it sounds.


----------



## LaughMoreDaily

raoultrifan said:


> Most likely not original MUSES on eBay at this price. Here's the correct price: http://www.profusionplc.com/parts/muses8920d - 7 USD each.


That's pretty awesome. A legit source too (same cost as potential fakes). Very cool. A great price. But it's sold out...


----------



## raoultrifan (Jun 13, 2018)

In the main page there are the 3 authorised vendors: https://www.njr.com/MUSES/index.html.



DIP8 8920D is indeed difficult to find for the moment, but SO8/SOIC could be an alternative too for DIY-ers.

L.E.: https://www.audiophonics.fr/en/comp...p-9612.html?search_query=8920d&fast_search=fs would be a trustable source as well, if you're happy with the pricing.


----------



## LaughMoreDaily

raoultrifan said:


> DIP8 8920D is indeed difficult to find for the moment, but SO8/SOIC could be an alternative too for DIY-ers.


Why do you think it's hard to find? The popularity of the 8920 or is it being discontinued (probably not?)


----------



## atmosfearz

LaughMoreDaily said:


> That's pretty awesome. A legit source too (same cost as potential fakes). Very cool. A great price. But it's sold out...


As for me better to buy cheapest 8920 (fakes are not always bad) than expensive 8920 without any idea If It's real. I would have ordered it for 7$ from this source, but real price is near 12$ on ebay.


----------



## LaughMoreDaily

atmosfearz said:


> As for me better to buy cheapest 8920 (fakes are not always bad) than expensive 8920 without any idea If It's real. I would have ordered it for 7$ from this source, but real price is near 12$ on ebay.


I've already been burned on a fake Muses 02. When I buy a Muses 8920 (the only one I want now) I'm buying it straight from a distributor in Japan.


----------



## Rroff (Jun 13, 2018)

Wonder what the fakes are - seen claims elsewhere they are probably NJM4556 and someone got what was almost certainly LM358 or something like that heh.

Given the price just not worth buying aside from straight from distributor.


----------



## atmosfearz (Jun 13, 2018)

Rroff said:


> Wonder what the fakes are - seen claims elsewhere they are probably NJM4556 and someone got what was almost certainly LM358 or something like that heh.
> 
> Given the price just not worth buying aside from straight from distributor.



Probably you are right but in my case I replace 5532 and there's more than 100 orders and reviews are saying of good sound whatever it is (link). There's still better question how to check and prove if it's fake.


----------



## SpudHarris

Are'nt the legs of Muses made from a softer but annealed material? That's how I thought you could check. Oh and of course buy from an authorised dealer...


----------



## atmosfearz (Jun 13, 2018)

SpudHarris said:


> Are'nt the legs of Muses made from a softer but annealed material? That's how I thought you could check. Oh and of course buy from an authorised dealer...


Actually I've heart that real muses are so weak and can be broken easily.


----------



## ScottFW

They're not unbelievably weak, but they break probably a bit easier than most. I broke one leg off a MUSES 8920 when removing to install sockets in my TEAC UD-301 (the 8920 were the stock chips). It was kind of a pain due to the chips being fit pretty tightly to the board... PCB hole spacing seemed a bit on the wide side relative to standard DIP8 chip leg spacing, so it was not possible to simply wick out all the solder and leave all 8 legs floating free in the middle of the holes. The corner legs were still physically touching their hole edges, so after wicking away as much as possible I'd have to heat again (the wave soldered lead-free joints also contributed to the fun) while gently pulling on the chip, and I broke one of the corner legs off the first 8920 I removed. First time I ever had that happen in years of doing this stuff. I exercised some paranoia while removing the remaining chips and managed to avoid any further breakage.


----------



## LaughMoreDaily

atmosfearz said:


> There's still better question how to check and prove if it's fake.


Muses should put a picture on their 8920 to make it easier to spot if someone fakes it. Right now just with text, it's really hard to tell.


----------



## SpudHarris

Listening with TO99 OPA637BM's that I bought from Farnell when I had a more disposable income. I paid about £40 each + VAT so the Muses01 in comparison isn't such bad value. SQ wise there really isn't much in it. Always had a liking of these since getting into this hobby and reading Tangents Pages. It was the first real class opamp I ever listened to and I believe it still rocks in the right application...

I will just don my fireproof jacket and say the genuine Muses01 is actually a bargain haha


----------



## LaughMoreDaily

SpudHarris said:


> I will just don my fireproof jacket and say the genuine Muses01 is actually a bargain haha


I'm not sure why you had to say Genuine? Genuine products always sound better because they sound like they're supposed to.


----------



## SpudHarris

Not sure I understand you??

A fake Muses01 would hardly be a bargain would itt? The context was a comparison against "genuine" OPA637BP so not sure what you are saying?

Personally given my time in this hobby and listening to others experiences I would never buy from  anywhere but a reputable source. If it looks too good to be true? It most certainly is!

Wow what a strange post...


----------



## Onik

canthearyou said:


> Here is my little review/comparison between a few opamps. I was gonna do a big write-up but, life has gotten in the way of any real free time.
> 
> See my amp mods here: http://www.head-fi.org/t/770610/int...and-hpa-3b-review-to-follow/150#post_12641691
> 
> ...



did you write this review after Burnin?


----------



## canthearyou

Onik said:


> did you write this review after Burnin?



They each had a little bit of burn in. Some more than others.


----------



## Onik

canthearyou said:


> They each had a little bit of burn in. Some more than others.



imo I find the Bursons vivid series are more livelier than Sparkos opas and also found vivids bass is more extended than Sparkos. in the case of soundstage I am not sure which one is the best, maybe I will need to burn my ss3602 few more days to find out.


----------



## canthearyou

Onik said:


> imo I find the Bursons vivid series are more livelier than Sparkos opas and also found vivids bass is more extended than Sparkos. in the case of soundstage I am not sure which one is the best, maybe I will need to burn my ss3602 few more days to find out.


I never tried the vivid series. The reviews are promising, though.


----------



## dhruvmeena96

SS2590 by sparkos 

Anybody tried their flagship op amp


----------



## Onik

dhruvmeena96 said:


> SS2590 by sparkos
> 
> Anybody tried their flagship op amp



I don't know what that thing is but all I can say is its not compatible with my Equipments.


----------



## dhruvmeena96

Onik said:


> I don't know what that thing is but all I can say is its not compatible with my Equipments.


Well true...

And yah..I forgot

OPA 1622 and OPA1688 are some extreme level cheap opamps.

Perfectly designed AGDR cmoy with Texas instruments TX2575 resistor on audio line and more upgraded components, costing somewhat 150$ is better than most of the burson opamps rolled in random hardware.


And yah, I forgot, if you have decent soldering skill with SMD, try changing the Burson V6 vivid resistor to tx2575 resistor..

@The Chief did this..  To V4

Texas instrument started tx2575 smd format

Or you can go rhopoint gg wirewound


----------



## The Chief (Jun 23, 2018)

dhruvmeena96 said:


> Well true...
> 
> And yah..I forgot
> 
> ...




Thank you so much. This is the first time that anyone takes a notice of what I´ve done.
To be honest, the photograph ist in prototype mode. Later versions look a little better (see new photograph. If you try to copy that work or do better, please folks, be aware , that I´ve listened to any single resistor. And there was a difference in sound every time. So I determined any resistor´s direction by listening. This is the case, no matter if you take TX2575 or Rhopoint GG102.  Burson has my sheme, so they could build it!!! And what nobody knows: Rhopoint 50 Ohm resistors sound better soldered the other direction.

My favourite Op amp is till now the rhopointed V4. But this one wins only in naturalness and natural sounding impulses. The cirquit of the V6 vivid seems to be better. V6 wins in punch and bass.
What I guess is: normal surface smd resistors don´t sound best. Unfortunately I don´t dare to rhopoint a Vivid. If somebody did, please let me know... 
ahh, last but not least: no sound differences in the small cap. But the trim sounds as well. I prefer the green Texas Components trims, they are the ones that sound brightest. (type 1240) If it´s too bright the 1260 sound a little mellower, but fine. But the pins are inline. maybe the 1242 is a good idea...


----------



## dhruvmeena96 (Jun 25, 2018)

The Chief said:


> Thank you so much. This is the first time that anyone takes a notice of what I´ve done.
> To be honest, the photograph ist in prototype mode. Later versions look a little better (see new photograph. If you try to copy that work or do better, please folks, be aware , that I´ve listened to any single resistor. And there was a difference in sound every time. So I determined any resistor´s direction by listening. This is the case, no matter if you take TX2575 or Rhopoint GG102.  Burson has my sheme, so they could build it!!! And what nobody knows: Rhopoint 50 Ohm resistors sound better soldered the other direction.
> 
> My favourite Op amp is till now the rhopointed V4. But this one wins only in naturalness and natural sounding impulses. The cirquit of the V6 vivid seems to be better. V6 wins in punch and bass.
> ...


we talked once about rhopoint and capacitor and cyro treatment....
I appreciated your work, actually that is something what you call modding and not the op amp swapping..

I still appreciate your work and because of you, I was able to improve my AGDR cmoy or Pocket O2 with opa1688..

I replaced all audio line resistors with tx2575, because I was not able to find rhopoint gg...

Noticed the blackness in the background.

Diyaudio guys told me that rhopoint gets even more dark..

Actually your mod did two things...got the hypersonic high frequency data back and should have dropped the harmonic distortion at 1kHz significantly....


Which lead to fundamental tone cleaning and soundstage expansion..

I did with my pocket O2(special cmoy with no ability to swap as it was designed just for opa1688)

It just sounds terrific..

I have to find rhopoint GG on cheap prices soon


----------



## The Chief

Ah , yes I remember you. That was always interesting, what you found out!!! I tried to get your resistors, but I couldn´t find them. Rhopoint can easily be bought at sales@rhopointcomponents.com
maybe you ask for Mrs Eleonore Hofmann . It´s not cheap, it´s from england and they have minimum quantity orders (crap), If you have an Idea where to buy your frozen resistors or you find out where to buy GG102 cheaper, just let me know...


----------



## Onik

dhruvmeena96 said:


> Well true...
> 
> And yah..I forgot
> 
> ...



is that V4? I do have soldering skills, but don't think I will ever touch the registors inside my V6 opas.


----------



## dhruvmeena96

Onik said:


> is that V4? I do have soldering skills, but don't think I will ever touch the registors inside my V6 opas.


Yes it is


----------



## The Chief

yes, my mod is V4. I opened a V6 vivid and had a look on the surface mount resistors. I think I can change one side, but I don´t dare to open it up completely and do the other side as well. I know somebody who could do that. They are sitting in Australia. I wonder how I can make them trying to rhopoint a V6 Vivid...


----------



## dhruvmeena96

The Chief said:


> yes, my mod is V4. I opened a V6 vivid and had a look on the surface mount resistors. I think I can change one side, but I don´t dare to open it up completely and do the other side as well. I know somebody who could do that. They are sitting in Australia. I wonder how I can make them trying to rhopoint a V6 Vivid...


Try tx2575...

I have tested both...

Rhopoint gives 2nd harmonic distortion a lift(very negligible) to make it sound better...

Tx2575 is void of all noises..

Actually try charcroft SCAR(better tx2575) resistor...

Those will sound immense.

Rhopoint is considered better due to its distorted(natural bass presentation)..

Try changing all parts to reference grade components(even in your amp or source). Don't use snake oil, just check the specs of components you are going to use.(I am talking about audio line as power line doesn't effect that much)

See, tube amps and other distorted things are better when used in production line(guitar amps, piano amps etc) as artist colours his music according to him... Tube amps and coloured amps are not a good thing because everyone don't have perfect pair of listening equipment (not everyone have a focal utopia), they are boosted somewhere and are coloured somewhere...

Then we use a coloured amp, so we loose all the nuances the artist intended just to listen that pleasurable distortion doesn't make sense...

@The Chief 

Try to make your amplifier/source as superior as it can in technical term is the way to go..

Its like pokemon, it gets stronger and stronger but not by a certain margin, but suddenly it evolves and become a heck lot stronger.

Try to remove noises and distortion as much as possible so that it becomes pitch black in background, then clean up the power line so that components in audio line gets stable and linear power.

Rhopoint is the best wirewound and may sound better than tx2575 but a overhaul of tx2575 everywhere can make a heck lot difference....

Agdr cmoy of mine is having a black hole type of noise...it actually cleans up so much noise that sometimes I feel my low quality music is cleaned up(well it still doesn't sound good, but then, it was better than stock BOM issued with agdr cmoy).

Don't care about holographic presentation and other subjective factors first because opamps and solid-state best part is technical superiority..the better the precision of the components, the better they get.

Rhopoint is wirewound and is best in terms of sound but it has that slight inductance of wirewound(rhopoint took inductance to minimum, but wirewound worst drawback is inductance). Inductance rolls off high frequency data(its 1000x times better than stock resistor) and distort the bass a little to make it more pleasing. TX2575 may sound sterile and clinical but if all parts of your source or Amps are replaced by tx2575, it will open a new world of details.

Its way way fast subbass that you an hear details out of lowest subbass and treble tightness. It somewhat makes sound critically damped and you can hear the control of it over the signal. So much tightness, signal comes and then goes completly in darkness.

Its like somebody plays an instrument and when is time is over, he doesn't linger around. Thus makes imaging to précis and accurate, that it makes soundstage more respectable and huge...

Hope this helps


----------



## dhruvmeena96

And by the way, tx2575 comes in smd format


----------



## numon

hi
 i bought philips x2 head phone i like its thick and fuller sound 
 and i wnat to  try  expensive opamps so 
 which one has has thicker( richer ,fuller)   sound :     muses 01 vs burson v5i vs  burson v6 classic    
 thanks in advance


----------



## Onik

numon said:


> hi
> i bought philips x2 head phone i like its thick and fuller sound
> and i wnat to  try  expensive opamps so
> which one has has thicker( richer ,fuller)   sound :     muses 01 vs burson v5i vs  burson v6 classic
> thanks in advance


 
burson v6 vivids/classic or sparkos opas.


----------



## dhruvmeena96

numon said:


> hi
> i bought philips x2 head phone i like its thick and fuller sound
> and i wnat to  try  expensive opamps so
> which one has has thicker( richer ,fuller)   sound :     muses 01 vs burson v5i vs  burson v6 classic
> thanks in advance


Always get an opamp opposite to your signature of your headphone


----------



## numon

Onik said:


> burson v6 vivids/classic or sparkos opas.


 thanks  
i had  v6 vivid  and i had a chance to  compare v6 vivid on o2 amp  and zishan  z2 stock opamp,z2 stock was better on  thicker fuller sound than vivid except ss and details


----------



## LaughMoreDaily

dhruvmeena96 said:


> Always get an opamp opposite to your signature of your headphone


Unless someone makes a list of which opamp has what signature it's hard to tell what they actually have.


----------



## numon

dhruvmeena96 said:


> Always get an opamp opposite to your signature of your headphone


 why opposite opamp if liked the signature of x2 ?


----------



## Onik (Jul 17, 2018)

numon said:


> thanks
> i had  v6 vivid  and i had a chance to  compare v6 vivid on o2 amp  and zishan  z2 stock opamp,z2 stock was better on  thicker fuller sound than vivid except ss and details



*I doubt you did Burn the vivids well, after the 100% Burn-in they will outperform any other ic op-amps you have, I am telling from my own listening experience.*


----------



## numon

Onik said:


> *I doubt you did Burn *
> 
> 
> Onik said:
> ...


----------



## dhruvmeena96

Numon, opposite nature opamp is used to get a warm headphone to get some nicer detail. Warm + warm turns out to messy.

Muse01 are crap crap opamp. Tube like distortion but a little skewed on 2nd and 6th harmonic.

Get a opa1688 agdr cmoy(neutral) or xrkaudio amp(warm).

And don't expect warm opamp to sound warm as opamp were never made for that purpose. Go buy some tubes.

Opamp master race never believes in warmth. Even muse is also cold with some track. It is just the distortion sounds warmer and lemme remind you, warm + warm is mesh in mids. Experience


----------



## dhruvmeena96

Its easy

Get the distortion charts on a dummy cmoy. Higher distortion are warm, lower distortion are detailed.

Even harmonic distortion is tube like and neutral line distortion is cold and analytical.


LaughMoreDaily said:


> Unless someone makes a list of which opamp has what signature it's hard to tell what they actually have.


----------



## raoultrifan (Jul 17, 2018)

dhruvmeena96 said:


> [...]
> Muse01 are crap **** opamp. Tube like distortion but a little skewed on 2nd and 6th harmonic.
> 
> Get a opa1688 agdr cmoy(neutral) or xrkaudio amp(warm).
> [...]



Actually, I found MUSES01 (the original ones) being the best I've tried in I/V stage of my Essence One DAC, well...at least better than MUSES8920, NE5532, AD8599, OPA1602, OPA1604, OPA2134,  OPA1652 etc.). THD is quite low based on Stereophile, Archimago's blog and similar websites (also in-house RMAA conducted tests).



dhruvmeena96 said:


> Its easy
> 
> Get the distortion charts on a dummy cmoy. Higher distortion are warm, lower distortion are detailed.
> 
> Even harmonic distortion is tube like and neutral line distortion is cold and analytical.



May I add here the phase-shift of the analog stage of the headamp/LPF/buffer that is definitely adding lot of warmth in the output sound?


----------



## raoultrifan

numon said:


> thanks
> i had  v6 vivid  and i had a chance to  compare v6 vivid on o2 amp  and zishan  z2 stock opamp,z2 stock was better on  thicker fuller sound than vivid except ss and details



In my Objective2 amplifier I got better results with BURSON SS V5 than SS V6 Classic/Vivid; it's not only about the output sound, but also about the "thump" sound that appears when powering ON and OFF the amplifiers and the output DC-voltage (lower "thump" with SS V5, actually lower than the original 2608 op-amp).


----------



## Onik

anyone tried this?: https://www.ebay.co.uk/itm/1pc-HI-E...rentrq:ad01d5041640a9e46b4f8b4cfff9ef70|iid:1


----------



## raoultrifan

With such a high offset voltage I wouldn’t recommend it for output buffer, nor for voltage gain, unless there’s a DC-offset opamp installed after output buffer.


----------



## LaughMoreDaily

Onik said:


> anyone tried this?: https://www.ebay.co.uk/itm/1pc-HI-End-Discrete-Mini-Dual-Operational-Amplifier-op-amp-module-NT1906B/312024982732?_trkparms=aid=777001&algo=DISCO.FEED&ao=1&asc=52955&meid=b851b032d1ea4d189f6df98625d1eb11&pid=100651&rk=1&rkt=1&&itm=312024982732&_trksid=p2481888.c100651.m4497&_trkparms=pageci:2b1e3af8-8a78-11e8-a150-74dbd180278a|parentrq:ad01d5041640a9e46b4f8b4cfff9ef70|iid:1


Good find but the price kills the deal for me. I'm not a millionaire.


----------



## spacequeen7

$189.00  ?..LOL get the..


----------



## SpudHarris

Can't justify that amount of dosh! I'm entranced by Muses01 at the moment and I consider them expensive.

For anyone out there who thinks the Muses01 are not top notch, you bought fakes. When starting out I made the same mistakes, I bought fake OPA637BP's for cheaper than Mouser/Farnell etc... And they were worse than some 'Jellybean' chips.

Genuine Muses01 are the benchmark at this time for me...


----------



## carlmart

Getting here now, and finding this Muses discussion.

Not very practical reading 408+ pages to find the start of this, so can someone tell me where to get more info?

The chip seems to be made by NJR and sold by Mouser and DK. Specs are average. But most of all: price is ridiculous! $46 for one chip?

Comments above look conflicting too.

For that kind of money I think I could assemble a sophisticated two-chip line amp like some Walt Jung published.

Am I wrong on my comments, as I never listened to it?


----------



## dhruvmeena96

I had the original muse01 and I find them okay to better, the fake one were just mehh

@The Chief take on burson opamp was an Eye-opener for me and I did it to my v6vivid.

No turning back from this point.

Offer me the ultimate class A biasing opamp or go home

When I joined head fi....I guess muse01 was one of the top leader

But OPA1622 and 1688, if build properly with and knowledge(talking about amps) are miles better than any opamps I have listened so far.(defeats the burson v6 modded in few aspect, but not on soundstage)

This is my observation, yours may vary


----------



## raoultrifan (Aug 28, 2018)

Please, don’t remember me about MUSES01 price, I have 4 of them installed in my Essence One combo.  For some reason these expensive chips are the best I’ve tried in I/V for E1 DAC.

However, 8920 is also a wire-with-gain in most circumstances and it’s way cheaper if you want to try it out.

Both of the above could be a good match for I/V and a very good choice for gain-stage and output buffer, given their high current output and very low DC-output.


----------



## The Chief

Thanks for the flowers, 



 
*dhruvmeena96                                    did you change the trim in your V6 as well? I´ve tried Texas Components 1240W in my V4 with good result compared to bourns trim. You may also think about 1260W, which sounds probably a little softer than 1240. But A far as I know , in the Vivid, the trim is very tiny, so the pins of Texas Components won´t fit into the holes of the V6 PCB. Tricky... maybe Texas C have smaller ones? Anyway, bourns trims steal more sound...  and congratulations to be the first man on the planet, who has a V6 with better resistors. Can I grow enough to be the second ? I m u s t have one...*


----------



## leeperry

me still love LT1028A, made Ray Samuels a rich man and got 10/10 for soundstage in an old opamp comparison, a b*tch to stabilize but SQ is too good 

of course you'll have to polish the rest of the rig coz it's not an utterly bright HiRes chip, yet not tuby to the least

I wish I could snag some LT1028ACH but they all appear to be fake, I got a really nice pair off ebay but seller refunded me after I asked whether they were genuine as they didn't match the NOS looking listing pic and they look too shiny to be true


----------



## dhruvmeena96

The Chief said:


> Thanks for the flowers,
> 
> 
> 
> ...


I got it done by a robot....actually a PCB manufacturing company is bear my home so I got it done there..we are dealing smd here 

And I didn't use potentio resistor...

Normal smd,I used these

https://www.rhopointcomponents.com/...igh-precision-resistor-0-05ppm-deg-c-typ.html


They are better than rhopoint wirewound


----------



## carlmart

Hasn't anyone tried the THS 4031 or 4032?

http://www.ti.com/product/THS4031

This chip has the potential to sound very good.


----------



## carlmart

dhruvmeena96 said:


> I had the original muse01 and I find them okay to better, the fake one were just mehh
> 
> @The Chief take on burson opamp was an Eye-opener for me and I did it to my v6vivid.



Which Burston?



> But OPA1622 and 1688, if build properly with and knowledge(talking about amps) are miles better than any opamps I have listened so far.(defeats the burson v6 modded in few aspect, but not on soundstage)



Very "anti-DIY" these chips. Difficult to handle and solder. 

On which DAC or boards are you using these chips? Are they on adaptors?


----------



## dhruvmeena96

carlmart said:


> Which Burston?
> 
> 
> 
> ...


Burson V6 vivid

And I am using 1688 on agdr CMOY and 1622 in fiio q1mk2


----------



## raoultrifan (Aug 28, 2018)

carlmart said:


> Hasn't anyone tried the THS 4031 or 4032?
> 
> http://www.ti.com/product/THS4031
> 
> This chip has the potential to sound very good.



I do like their high current and low impedance drive capabilities, hence these opamps could be a great output buffer. Do note the lower THD for THS4931 vs. THS4032: -96dB vs. -90dB.


----------



## carlmart

Both THDs are also higher than the OPA1622.


----------



## raoultrifan (Aug 28, 2018)

And OPA1622 has a strange package type and a bit higher noise, but this why this thread is so long and fun to read, right?


----------



## carlmart

Yes, I do not like the OPA1622 package, except if someone delivers it soldered to an adapter. 

The other thing is that I mainly interested in line level opamps, not headphone amps. 

I wonder if you got to some agreement on these pages about line level chips.


----------



## carlmart

Well, risking getting a fake OPA1622, I have just bought one from eBay. It's already on a DIP8 adapter, power pins bypassed.

It was just $6.66, so if it's false it won't be much.

But please do suggest an IC that shines at line level.


----------



## leeperry (Aug 28, 2018)

carlmart said:


> Very "anti-DIY" these chips. Difficult to handle and solder.


1688 is available as SOIC8, diyinhk gives them away presoldered on DIP8 for that matter


----------



## carlmart

leeperry said:


> 1688 is available as SOIC8, diyinhk gives them away presoldered on DIP8 for that matter



Gives them away? Where?


----------



## zilch0md

I paid $75 each for two Muses02, from Mouser, at a time when they were difficult to find (Feb. 2014).  

About four months later, I tried to trade them here on Head-fi suggesting an even swap for Muses01.   I kept that classified up for another four months and then killed it.

I still haven't heard the Muses01.   It must be nice, if nobody wants to swap a pair for Muses02.   I refuse to put any more money into Muses opamps after getting "talked into" the Muses02 and hating them.   LOL


----------



## dhruvmeena96

zilch0md said:


> I paid $75 each for two Muses02, from Mouser, at a time when they were difficult to find (Feb. 2014).
> 
> About four months later, I tried to trade them here on Head-fi suggesting an even swap for Muses01.   I kept that classified up for another four months and then killed it.
> 
> I still haven't heard the Muses01.   It must be nice, if nobody wants to swap a pair for Muses02.   I refuse to put any more money into Muses opamps after getting "talked into" the Muses02 and hating them.   LOL


MUSES01 is something collectible and not a normal opamp. It sounds damm clean
MUSES02 is a warm opamp and if not paired well, can turn muddy.

Hope this clear your doubts on MUSES02


----------



## raoultrifan

carlmart said:


> [...]
> The other thing is that I mainly interested in line level opamps, not headphone amps.
> I wonder if you got to some agreement on these pages about line level chips.



Not sure I fully understand the question, sorry. Line level means >1V RMS for at the source input of the amplifier, so most headamps are line input. Also, headamps THD and SNR is expresses at around 2V RMS input signal. Could you please be more specific?



carlmart said:


> [...]
> It was just $6.66, so if it's false it won't be much.



The price is just not right, feel free to remove the "." and you'll realise that too. 

BTW, the NE5532 has the max. input voltage of Vcc+, where Vcc+ would be the positive voltage rail. I believe all audio opamps can get 1-2V RMS at their V+ or V- inputs without any issues, if that's what you're asking about.


----------



## raoultrifan

zilch0md said:


> [...]I refuse to put any more money into Muses opamps after getting "talked into" the Muses02 and hating them.   LOL


In what device and what exact "stage" has you tested the 2 x MUSES02, please?
I tested this with great results in LowPass filters, output stages and also in gain stages. At this moment my Matrix HPA-3B is using 2 x MUSES02 and I find them very low noise (despite their datasheet), with very good soundstage and very musical opamps.


----------



## dhruvmeena96

raoultrifan said:


> In what device and what exact "stage" has you tested the 2 x MUSES02, please?
> I tested this with great results in LowPass filters, output stages and also in gain stages. At this moment my Matrix HPA-3B is using 2 x MUSES02 and I find them very low noise (despite their datasheet), with very good soundstage and very musical opamps.


MUSES02 is very application specific like output stages (not sure about gain stages, because it didn't fair well for me)
MUSES01 outclasses all the OPAMPs when used in I/V stage of a DAC or an AMP(especially DAC)


----------



## Rroff

raoultrifan said:


> The price is just not right, feel free to remove the "." and you'll realise that too.



Heh yeah - last time I looked at some cheap MUSES someone got I'm 99% sure they were actually NJM4556.


----------



## dhruvmeena96

i have seen  many people re badging njm4556 and muses8920 as muses01 and 02.


----------



## carlmart (Aug 29, 2018)

raoultrifan said:


> Not sure I fully understand the question, sorry. Line level means >1V RMS for at the source input of the amplifier, so most headamps are line input. Also, headamps THD and SNR is expresses at around 2V RMS input signal. Could you please be more specific?



I am referring to output voltage level. Of course you can use many opamps as headphone amps, but not all opamps can drive a headphone well.

Distortion demands are more critical on opamp that will feed a power amp, than on one that will drive a headphone. S/R and noise are not too important on a headphone amp, and they are on a line amp.

Some, including me, do not find absolutely necessary to use a line preamp between source and power amp, and modern sources are juicy enough to drive most power amps perfectly.

But I think that an output DAC chip does sound better if it's fast and low noise, besides having as low distortion as possible.




> The price is just not right, feel free to remove the "." and you'll realize that too.



Why it's not right? Mouser is selling the 1622 for $6.



> BTW, the NE5532 has the max. input voltage of Vcc+, where Vcc+ would be the positive voltage rail. I believe all audio opamps can get 1-2V RMS at their V+ or V- inputs without any issues, if that's what you're asking about.



Output level is what I mean, not input level.


----------



## raoultrifan

If looking for unity gain output buffers able to drive cans, then NJM4556 will do (see O2). However, perhaps something like http://www.ti.com/lit/ds/symlink/opa551.pdf would be better...or the OPA552, depends on your needs.

If looking for preamps, then any audio opamp unity gain stable could be used.

If you’re looking for some other design, then please provide a schematic, for a better understanding. 

I was not reffering to the price, instead to the number itself. Yes, I’m an orthodox.


----------



## dhruvmeena96

carlmart said:


> I am referring to output voltage level. Of course you can use many opamps as headphone amps, but not all opamps can drive a headphone well.
> 
> Distortion demands are more critical on opamp that will feed a power amp, than on one that will drive a headphone. S/R and noise are not too important on a headphone amp, and they are on a line amp.
> 
> ...


Nowadays preamp is not a separate thing but a part of modern amp schematics(not all, but most of them), so there is no need to buy one until or unless it is damm necessary(and if somebody is rich, get a burson cable, the one with opamp one....)

And I agree with DAC statement.... DAC are just too sensitive with the parts they are connected with... Even the change of quality resistor change the perceived sound profile, so they will get a lot of advantages with opamps...that I am sure of


----------



## carlmart

In this specific case I'm referring to opamps to be used as DAC output, driving a preamp or power amp. Never headphones.


----------



## zilch0md

Responding to some questions asked above...

I've only tried the 2x Mouser Muses02 in the input stage of an iBasso PB2 amp.  I have no doubts about how they sound to my ears with my gear.  They suck!  

They are anything but accurate in terms of frequency response and poorly resolving of fine detail.  And I've tried using them with numerous opamps in the buffer stage, including dummy buffers, which always provide the clearest impression of what's happening in the input stage. 

I personally prefer my DACs and Amps to be neutral and clean.  If I want to add color, I do it by switching headphones.  The Muses02 just has too much personality for my tastes.

Surely, there are people who would love what I'm hearing with the Muses02, so there's no right or wrong here.


----------



## raoultrifan

carlmart said:


> In this specific case I'm referring to opamps to be used as DAC output, driving a preamp or power amp. Never headphones.



Got it now, you need a good opamp as output buffer, so most audio opamps should work fine here.

If there is DC-servo or capacitors to block the DC from outputs, then I would recommend anything from: LME49720/LME4562, MUSES8820, MUSES02 to BURSON SS V6 etc.

If output DC needs to be very low, then FET-input opamps might help here: MUSES8920, MUSES01, OPA1652 etc.

Usually I got perfect results with LME49720, MUSES8820 or with MUSES8920, so unless you want to spend lot of money here you should be fone with the above opamps. Also, 8920 is able to drive less than 1KOhm impedance and has lot of mA to spare.


----------



## raoultrifan (Aug 29, 2018)

zilch0md said:


> [...]
> I've only tried the 2x Mouser Muses02 in the input stage of an iBasso PB2 amp.  I have no doubts about how they sound to my ears with my gear.  They suck!


That’s odd, first time I hear that. These opamps need carefully designed PCB and very good decoupling, perhaps this would be the case...not sure.



zilch0md said:


> They are anything but accurate in terms of frequency response and poorly resolving of fine detail.


I tried MUSES02 in too many devices and everytime I measured the outputs are perfect (low DC, perfectly flat, good separation), so unless there’s a clear incompatibility there should be no issues with freq response or fine resolution. Also, because channel separation is usually better with MUSES02, soundstage is a bit bigger.

Perhaps iBasso PB2 is not the best equipment to pair MUSES02 with.


----------



## dhruvmeena96

zilch0md said:


> Responding to some questions asked above...
> 
> I've only tried the 2x Mouser Muses02 in the input stage of an iBasso PB2 amp.  I have no doubts about how they sound to my ears with my gear.  They suck!
> 
> ...


Not a DAP thing...

Never performed good on DAPs


----------



## carlmart (Aug 29, 2018)

raoultrifan said:


> Got it now, you need a good opamp as output buffer, so most audio opamps should work fine here.
> 
> If there is DC-servo or capacitors to block the DC from outputs, then I would recommend anything from: LME49720/LME4562, MUSES8820, MUSES02 to BURSON SS V6 etc.
> 
> ...



All these chips are not that good in slew rate, which I remember was important on DAC outputs.

This is from the time first CD players were released and modified, particularly in The Audio Amateur. My subjective findings were similar.

Current capability was another one.

That doesn't mean I won't be willing to try some of these options and which sounds best to my ears.


----------



## selvakumar

raoultrifan said:


> Please, don’t remember me about MUSES01 price, I have 4 of them installed in my Essence One combo.  For some reason these expensive chips are the best I’ve tried in I/V for E1 DAC.
> 
> However, 8920 is also a wire-with-gain in most circumstances and it’s way cheaper if you want to try it out.
> 
> Both of the above could be a good match for I/V and a very good choice for gain-stage and output buffer, given their high current output and very low DC-output.


hi will it be good for Burson Play Muses opamps


----------



## raoultrifan

carlmart said:


> All these chips are not that good in slew rate, which I remember was important on DAC outputs.[...]



Forget about the slew rate, this is snake oil: https://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php. I don’t know what do you understand by “line level”, but for quitar that’s 0.8-0.9V RMS and for a regular DAC that would be 2-2.2V RMS. That means any audio opamp can handle line-level voltages when used in output buffer.


----------



## raoultrifan

selvakumar said:


> hi will it be good for Burson Play Muses opamps



Actually MUSES8920 are quite a good match in IV and LPF on my PLAY, though I like more 3xAD8599 (IV&LPF) + 2xAD797 (gain).


----------



## dhruvmeena96 (Aug 29, 2018)

raoultrifan said:


> Forget about the slew rate, this is snake oil: https://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php. I don’t know what do you understand by “line level”, but for quitar that’s 0.8-0.9V RMS and for a regular DAC that would be 2-2.2V RMS. That means any audio opamp can handle line-level voltages when used in output buffer.


i was not clear by the snake oil. are you saying that slew rate is snake oil?????

by the way, i was working on a project where i am using a Khadas Vim2 max development board as slave to Khadas Tone(ESS 9038) and then using the balanced L and R line out to a portable headphone amp which can operate on both balanced and unbalanced mode. this is all in one portable package

i need help with
1. size of amp should be small and should be as powerful as CMOY(Good driving till 300ohms)
2. what are the best opamps which consume very tiny power yet perform very good(OPA1622 is hard to deal so i am still on OPA1688, but better opamps are welcome)
3. battery is 10,000mAH 7.4V which has to be shared with all components, so if i can get a battery management circuitary info from somebody on personal chat.


----------



## carlmart

raoultrifan said:


> Forget about the slew rate, this is snake oil: https://www.radio-electronics.com/info/circuits/opamp_basics/operational-amplifier-slew-rate.php. I don’t know what do you understand by “line level”, but for quitar that’s 0.8-0.9V RMS and for a regular DAC that would be 2-2.2V RMS. That means any audio opamp can handle line-level voltages when used in output buffer.



A very serious and respected audio engineer, Walt Jung, considers slew rate a very important thing on an opamp, so I don't need to read anything that might claim that is snake oil. 

It's related to the capacity for the DAC filtering being done as fast as possible, and the analog opamp being able to be fast. On his first mods in TAA (you should find them and read them) on Philips CD players he used a fast IC and a video buffer to modify the original DAC. 

And yes, line level is about that voltage you mention, and yes, most opamps have the capacity to output that. Other things, like distortion, slew-rate, current capacity, etc. contribute to the chip sounding in a particular way, that some consider "better".

Those opinions, based on listening experience, is that I would like to have. Contrary to many audio engineers, certainly not Walt Jung, I believe in subjective opinions to evaluate audio, along with measurements.


----------



## raoultrifan

What I was trying to say is that for an opamp used as output buffer slew rate is definitely not important, feel free to read the above calculator. Mackie, JBL a.s.o. are building audio monitor speakers around NJM/JRC opamps with a slew rate of 3V/uS to 5V/uS and musicians and audiophiles appreciate these speakers as having a very good audio quality. So, in this case more slew rate is indeed snake oil and not even AP equipment will "see" any differences between a 2V/uS and a 20V/uS opamp if used within the audio bandwidth only.

A fast opamp could help when used in I/V stage, sometimes in gain stage (RIAA or mic or is higher gains are used), but not as unity gain buffer.

1. OPA1688
2. OPA2608 (good for gain stage, not so good for output buffer)

For all your 3 questions I suggest you to use the diyaudio forum instead. You'll definitely get more luck in there.

P.S.: A good output buffer might also be http://www.ti.com/product/LME49724. It has great specs and huge output current for such a small-case opamp (SOIC8 with power pad).


----------



## dhruvmeena96

raoultrifan said:


> What I was trying to say is that for an opamp used as output buffer slew rate is definitely not important, feel free to read the above calculator. Mackie, JBL a.s.o. are building audio monitor speakers around NJM/JRC opamps with a slew rate of 3V/uS to 5V/uS and musicians and audiophiles appreciate these speakers as having a very good audio quality. So, in this case more slew rate is indeed snake oil and not even AP equipment will "see" any differences between a 2V/uS and a 20V/uS opamp if used within the audio bandwidth only.
> 
> A fast opamp could help when used in I/V stage, sometimes in gain stage (RIAA or mic or is higher gains are used), but not as unity gain buffer.
> 
> ...


Ohh lol...

And I interpreted it in different way...lol


----------



## raoultrifan (Aug 29, 2018)

carlmart said:


> A very serious and respected audio engineer, Walt Jung, considers slew rate a very important thing on an opamp, so I don't need to read anything that might claim that is snake oil.



I'm sure most of us know about Walt Jung and about his work, he was like father of audio engineering. I remember I've read about some mods he did on a Philips CD player, but it was related to the DAC chip from inside, something related to the digital FIR filters, then he also biased an opamp to class-A, then he bypassed some opamps with additional capacitors as well, but don't think he used video opamps as output buffers...really don't see why to do that for.



carlmart said:


> Contrary to many audio engineers, certainly not Walt Jung, I believe in subjective opinions to evaluate audio, along with measurements.



Me too, but measurements first and if these fail then I care not about how it sounds. I've heard fast opamps sounding so great...with an interesting soundstage and vocals were so rounded and pleasant to my ears, but when I connected my scope I've only seen ringing and oscillations.

Feel free to read about the slew rate here: https://www.eetimes.com/document.asp?doc_id=1278805&page_number=2, actually all the pages from this article explain very well many well-know opamp specs.


----------



## carlmart

For that project he used the LH0002 as output buffer, and a very fast IC for the I/V. Jung also suggested a fast discrete buffer instead of the LH0002.

Later on he also modified a Philips DAC, but I do not remember the chips he used. 

OTOS I don't think you need high slew rate on a power amp, so Mackie's or JBL's audio monitors serve very much as an example. 

And Jung did suggest that video buffers were recommended for DACs. Other projects on that mag used them. 

Also fast opamps are prone to oscillation if you don't implement it alright, particularly if they are current feedback types. So I'm not sure your ringing or oscillation observations should rule out fast buffers for an output DAC, which Jung did recommend.


----------



## Rroff (Aug 29, 2018)

While generally you don't need massive slew rates to hit the threshold for reproducing audio one thing to watch out for is that many opamps either state a "typical" rate rather than a minimum and/or use slightly different scenarios for where/how the slew rate was measured. I'm pretty certain some opamps that on paper have a "typical" slew rate that is "good enough" for audio aren't consistently managing it especially in DIY installations and aiming for some reasonable overhead is a good idea if you don't have the experience and/or equipment to test for it.

From an earlier conversation I think some of the subjective experience that tends to show slew rates as mattering often boiled down to a mixture of signal step response and/or cable length causing enough capacitive load to reduce the opamp's performance causing the actual issue people were seeing rather than straight up being the slew rate itself.


----------



## raoultrifan (Aug 29, 2018)

I thought we're speaking about output buffers of an audio equipment (line level), not DAC voltage-out or current-out buffers.
However, for DAC buffers I totally trust manufacturer's specs. For example, LM4562/LME49720 is quite OK for use in both I/V and LPF. I'm not saying it's the best, but it's a very good opamp.

L.E.: LH0002 was replaced by BUF634 and LME49600/49610 250mA output buffers. These are output buffers for driving 16-600 Ohms headphones, not for line level outputs (>10 KOhms impedance).


----------



## selvakumar

raoultrifan said:


> Actually MUSES8920 are quite a good match in IV and LPF on my PLAY, though I like more 3xAD8599 (IV&LPF) + 2xAD797 (gain).


im gona order it and how to put 
Analog Devices Inc. AD8599 only SOIC-8 package available


----------



## raoultrifan

SOIC-8 are mines as well, but I was able to DIY adapters for them. You can probably find already soldered on SOIC-DIP8 adapters.
You can also find AD797 in DIP8 package; these are extremely low-noise opamps and very recommended in gain stages.


----------



## CoiL

Any ideas how I can feed Burson V5i-D opamp properly in my Aune T1 ? Build separate power feed circuit from power brick entrance? Or modify existing amp section board? I really wish to get it working but it won`t power up properly instead NE5532A chip.


----------



## raoultrifan

After taking a look to http://www.pt80.net/thread-451874-1-1.html and used Google translate I see that OPA2134 is used for DAC output, hence it could get replaced by LME49720 or MUSES8920, and NE5532 could get replaced by LME49720 or similar SO8/SOIC8 opamps.

If you do have enough space between the PCB and the outer case, then you should be able to solder the V5i directly on PCB to replace existing NE5532, but lot of care is needed and perhaps some 5mm long wires.

Given the complexity of this task I would honestly not recommend you to install V5i in Aune T1, I would vote instead with LME49720, AD8599 or MUSES8820/8920 with confidence.


----------



## BoomBap08

Has anybody already had the chance to compare ad8397 against muses8920? And which one's better? Thanks!


----------



## dhruvmeena96

Tell me the application

Output buffer with ad8397 is very detailed and clean. Muses is more musical with some good low end texture.


----------



## yurt28

raoultrifan said:


> I do like their high current and low impedance drive capabilities, hence these opamps could be a great output buffer. Do note the lower THD for THS4931 vs. THS4032: -96dB vs. -90dB.


That is True by 6DB, but the big difference is 1 channel Vs 2


----------



## yurt28

BoomBap08 said:


> Has anybody already had the chance to compare ad8397 against muses8920? And which one's better? Thanks!


Ad8397 is fun power wise with flat details, but against Muses8920 loudness can increase up to 139DB and is balanced. I haven't heard any hissing when listening at full blast.


----------



## yurt28

dhruvmeena96 said:


> Numon, opposite nature opamp is used to get a warm headphone to get some nicer detail. Warm + warm turns out to messy.
> 
> Muse01 are crap **** opamp. Tube like distortion but a little skewed on 2nd and 6th harmonic.
> 
> ...


"You said muses 01 is crap", Try running it through a Dac on your computer, the details are the best i have ever heard for being able to change sound that quick in and out


dhruvmeena96 said:


> Numon, opposite nature opamp is used to get a warm headphone to get some nicer detail. Warm + warm turns out to messy.
> 
> Muse01 are crap **** opamp. Tube like distortion but a little skewed on 2nd and 6th harmonic.
> 
> ...


"You said Muses01 are crap", have you tried running it through a dac on a computer? For games and movies it's the best i've ever heard detailed wise (almost realistic)


----------



## dhruvmeena96

yurt28 said:


> "You said muses 01 is crap", Try running it through a Dac on your computer, the details are the best i have ever heard for being able to change sound that quick in and out
> 
> "You said Muses01 are crap", have you tried running it through a dac on a computer? For games and movies it's the best i've ever heard detailed wise (almost realistic)


It is crap for IV conversion for me.

If set up in output stage, it is really good.

All muses do good on output, but I think its expensive price is not justifiable in comparison to Burson or sparkos labs. Even the KISS(keep it simple, stupid) series of TI(opa 1622 and 1688) defeats muses, if you have a application specific design.

Muses needs a circuit designed for itself to really shine the best(benchmark DAC1 mod)....which is hard and pretty cost consuming(with time)...

So muses is overall crap for value its offering..

But muses 01 is way better than 02 and other series


----------



## raoultrifan

dhruvmeena96 said:


> It is crap for IV conversion for me.
> [...]



That's odd, I wonder if you had a fake or an original. Most headfiers found the sound with MUSES01 used in I/V as being bigger, more detailed and better than NE5532, LME49720 and MUSES8920.

In what DAC have you used it, please?

Thanks!


----------



## dhruvmeena96

raoultrifan said:


> That's odd, I wonder if you had a fake or an original. Most headfiers found the sound with MUSES01 used in I/V as being bigger, more detailed and better than NE5532, LME49720 and MUSES8920.
> 
> In what DAC have you used it, please?
> 
> Thanks!


Sorry....that was a buffer all the time...I checked it....and swapped it..

It is sort of unnaturally large stage with way smoother treble(I need detailing like burson). It does good definition on bass side

Muses8920 is smaller brother,so I can expect that, but I find LME49990, opa1622 and burson v6 way better than muses01


----------



## dhruvmeena96

I have benchmark media DAC1 self modified(mistake corrected today....thanks @raoultrifan ) and benchmark media DAC3HGC


----------



## raoultrifan

Oh, so MUSES01 was basically installed as output buffer? I got it then...kinda expensive opamp for an output buffer for line-level I'd say. It makes more sense to install it in the place where manufacturer designed it for: I/V or optionally in active LowPass Filter.

DAC3HGC is able to raise a new bar in audiophile measurements with cheap and regular SO8/SOIC opamps like LME49860, so I assume you might have no needs to roll any opamps inside, right?  At least given it's extremely low 2nd and 3rd order harmonics (<-100dB) and very low jitter too, I would consider any type off modding to this DAC as being...sort of a bad joke or nonsense (unless someone provides a valid proof that I'm wrong). 

BTW, any thread or pics on what you've done to DAC1, please?


----------



## dhruvmeena96 (Sep 4, 2018)

raoultrifan said:


> Oh, so MUSES01 was basically installed as output buffer? I got it then...kinda expensive opamp for an output buffer for line-level I'd say. It makes more sense to install it in the place where manufacturer designed it for: I/V or optionally in active LowPass Filter.
> 
> DAC3HGC is able to raise a new bar in audiophile measurements with cheap and regular SO8/SOIC opamps like LME49860, so I assume you might have no needs to roll any opamps inside, right?  At least given it's extremely low 2nd and 3rd order harmonics (<-100dB) and very low jitter too, I would consider any type off modding to this DAC as being...sort of a bad joke or nonsense (unless someone provides a valid proof that I'm wrong).
> 
> BTW, any thread or pics on what you've done to DAC1, please?


I just swapped opamps...that was on diyaudio and was a preproduction series DAC1...(it had adapters instead of soldering)

I can't remember exactly...I have to find pic on my computer for that


I haven't touched DAC3 and dont want to even try In my dreams bro

That was DAC1 I modified

Muses and burson only went into dac1

Other opamp were cmoy projects and O2 swaps

I am a headphone guy, I dont really have speaker ampsto try with


----------



## CoiL

raoultrifan said:


> After taking a look to http://www.pt80.net/thread-451874-1-1.html and used Google translate I see that OPA2134 is used for DAC output, hence it could get replaced by LME49720 or MUSES8920, and NE5532 could get replaced by LME49720 or similar SO8/SOIC8 opamps.
> 
> If you do have enough space between the PCB and the outer case, then you should be able to solder the V5i directly on PCB to replace existing NE5532, but lot of care is needed and perhaps some 5mm long wires.
> 
> Given the complexity of this task I would honestly not recommend you to install V5i in Aune T1, I would vote instead with LME49720, AD8599 or MUSES8820/8920 with confidence.



The thing is - V5i-D was sent for me for reviewing and was told it is just directly swappable (not about the socket) with NE5532A. 
I already soldered V5i instead NE5322A chip an double checked intallation pins. Unit powers up but sound out of HP OUT is only in one channel and when I turn vol button it changes side to other side, both sides sound very weak and distorted/distinct. I was told it is probably because of not enough power for chip.
I already ordered new NE5532A chip and was wondering if I could do something to power up V5i-D properly? 
I don`t know if I bother to try it instead OPA2134, as it might not power up properly also.


----------



## raoultrifan

Not sure if it's related to power...hard to say. Most likely V5i is not compatible here, perhaps you might want to review V5i in a different equipment.


----------



## dhruvmeena96

Its related to power

18v swing needed in most cases as told by burson customer support(but I have seen some people running on single battery)

I dont know which device @CoiL is using....so I am not clear what the prob is


----------



## raoultrifan

dhruvmeena96 said:


> Its related to power
> 
> 18v swing needed in most cases as told by burson customer support(but I have seen some people running on single battery)
> 
> I dont know which device @CoiL is using....so I am not clear what the prob is



+/-5V power rails, per https://drive.google.com/file/d/0Bxn23njCr8VCWGh4bHBZYTVLYWs/view.

Either a soldering issue, either an incompatibility between opamp and Aune T1 device.


----------



## dhruvmeena96

raoultrifan said:


> +/-5V power rails, per https://drive.google.com/file/d/0Bxn23njCr8VCWGh4bHBZYTVLYWs/view.
> 
> Either a soldering issue, either an incompatibility between opamp and Aune T1 device.


Thanks bro


----------



## CoiL

raoultrifan said:


> Not sure if it's related to power...hard to say. Most likely V5i is not compatible here, perhaps you might want to review V5i in a different equipment.


Well, I asked before they sent it to me to be sure if it will be easy swap and they told me it should be directly replaceable with NE5532A & OPA 2134 with no additional hassle.


dhruvmeena96 said:


> Its related to power
> 18v swing needed in most cases as told by burson customer support(but I have seen some people running on single battery)
> I dont know which device @CoiL is using....so I am not clear what the prob is


Aune T1 power brick is +-15V voltage swing but not sure how much is the output by HP amplifier board to HP opamp chip. I will measure it if I have chance soon (busy).
Burson support also wanted me to measure V5i-D pins to be sure it is getting enough power. 
Well, I think I will install swappable socket first and then it will be easier to test different opamps anyway. 
But wish to give V5i-D another chance as it is much appreciated chip here and HP amp is "weakest" thing about Aune T1 (though, I have already changed capacitors to silmicII which made very noticeable change to better SQ).


----------



## SpudHarris (Sep 11, 2018)

raoultrifan said:


> That's odd, I wonder if you had a fake or an original.
> 
> Thanks



100% Fake! Anyone querying the quality of Muses01 in a "decent" application has been duped.

Nobody likes to admit they have been ripped off.


----------



## SpudHarris (Sep 11, 2018)

Deleted...


----------



## LaughMoreDaily

I can't believe you guys are still talking to each other... you were not for weeks!


----------



## carlmart (Sep 13, 2018)

Has anyone tried these LKS discrete opamps?

Single:
https://www.ebay.com/itm/LKS-Class-...100905?hash=item3f9162a5a9:g:yuYAAOSws0JaWLIQ

Dual:
https://www.ebay.com/itm/1-pcs-LKS-...889293?hash=item1ec1874f8d:g:GfgAAOSwfVpYomhv


----------



## carlmart

What about these ones?

https://www.ebay.com/itm/Dual-Discr...905026&hash=item3fa35df1ce:g:ChoAAOSwmtBbMzNC


----------



## raoultrifan

Nice 3D randering.  Too bad there're no specs...or at least I cant' find any.

I would honestly stick to regular audio op-amps, unless some real tests will appear with these eBay op-amps.


----------



## carlmart

In my case it's three that I would need to replace on my DAC. 

If it was just one I would take the risk.


----------



## tomb

carlmart said:


> What about these ones?
> 
> https://www.ebay.com/itm/Dual-Discr...905026&hash=item3fa35df1ce:g:ChoAAOSwmtBbMzNC



Ha ha - "Dual Discrete" when there's at least 7 SMD IC chips on each board.


----------



## carlmart

Maybe you should look again at the IC chips, and reconsider. 

Do you know that dual transistors and fets come in 6 pins SMDs? So they can be discrete indeed. 

That doesn't mean that I wouldn't like to know what's their schematics.


----------



## tomb

carlmart said:


> Maybe you should look again at the IC chips, and reconsider.
> 
> Do you know that dual transistors and fets come in 6 pins SMDs? So they can be discrete indeed.
> 
> That doesn't mean that I wouldn't like to know what's their schematics.



Yes, I know that.  Have you actually soldered them into place and used them in a circuit?  I have.  The "THAT Corporation" transistor arrays seem particularly good.

However, even if those are transistor arrays in monolithic packages, that doesn't meet the definition of "discrete."


----------



## carlmart

Maybe we have different definitions of what is discrete. 

Transistor arrays, starting with duals, certainly discrete parts for me. With great advantages, like temp sharing and transistor matching, which are difficult and expensive to accomplish with separate parts.

Quite different from an opamp, which is a complete circuit inside.

In any case, the question would be to get a schematic showing what's inside, and try one, of course.


----------



## FritzS

carlmart said:


> Maybe we have different definitions of what is discrete.
> 
> Transistor arrays, starting with duals, certainly discrete parts for me. With great advantages, like temp sharing and transistor matching, which are difficult and expensive to accomplish with separate parts.
> 
> ...



Look here, you found some dual JFETs and dual BJTs
http://www.linearsystems.com/product.html


----------



## tomb

carlmart said:


> Maybe we have different definitions of what is discrete.
> 
> Transistor arrays, starting with duals, certainly discrete parts for me. With great advantages, like temp sharing and transistor matching, which are difficult and expensive to accomplish with separate parts.
> 
> ...



Some transistor arrays come pre-biased with resistors inside.  Or, they have diodes, too.  You are correct that we really don't know unless we see a schematic.  However, I think the combination of 6-pin monolithic chips, Douk Audio, ebay, and non-English sourcing/description leads to a strong suspicion that their description of "discrete" might be a stretch.


----------



## Rick_B

carlmart said:


> What about these ones?
> 
> https://www.ebay.com/itm/Dual-Discr...905026&hash=item3fa35df1ce:g:ChoAAOSwmtBbMzNC



I just received one this week but haven't had a chance to put it in anything yet....going to try it in place of a Burson V5i in a Little Dot 1+ with Western Electric tubes in it and see what the differences are....

Construction looks nice on first examination...more later...


----------



## carlmart

Looking forward to read your findings.


----------



## Rick_B

carlmart said:


> Looking forward to read your findings.



OK, I inserted this little opamp today and have let it play now for 8 hours or so....

It is not a downgrade from the Burson V5i it may be a slight bit "mellower", but that's more of a fleeting impression...

More later if I get time to do critical tests.


----------



## LaughMoreDaily

Rick_B said:


> OK, I inserted this little opamp today and have let it play now for 8 hours or so....
> 
> It is not a downgrade from the Burson V5i it may be a slight bit "mellower", but that's more of a fleeting impression...
> 
> More later if I get time to do critical tests.


We look forward to your tests. I heard this space-like opamp is bright sounding. I guess you'll find out if it's true or not.


----------



## carlmart

Sounding different, and not worst, from the Burson is promising.

Looking forward to what the differences turn out.


----------



## Rick_B

LaughMoreDaily said:


> We look forward to your tests. I heard this space-like opamp is bright sounding. I guess you'll find out if it's true or not.



It almost seems, especially on Head-Fi, that one person's "bright" is another's "transparent"...same with bass response.

I did not notice this opamp sounding too bright, too brittle, too distorted in the treble region whether using my SR225e's, He-400i's, or really any other set I tried with it.

I also like to reserve my judgement until a piece of electronics has been run in for at least a week, I've been playing this hi-fi game for over fifty years and it never ceases to amaze me how much some electronic gear can change just by being run in...


----------



## leeperry

Rick_B said:


> I did not notice this opamp sounding too bright, too brittle, too distorted in the treble region


According to Scott Wurcer(the designer of the holy AD797), opamps have no sonic character and it's all highly dependent on how they are used and especially if they are not oscillating. To EE's we're clueless idiots rolling opamps blindly.


----------



## Ivan TT

Similar tune from Douglas Self:


> With horrible inevitability, the very popularity and excellent technical performance of the 5532 has led to it being criticized by subjectivists who have contrived to convince themselves that they can tell op-amps apart by listening to music played through them. This always makes me laugh, because there is probably no music on the planet that has not passed through a hundred or more 5532s on its way to the consumer.


----------



## carlmart

The objective vs subjective discussion is never ending when talking with most electronics engineers. 

It seems they do not want really to hear or maybe are afraid that something comes up that they can't explain. 

No surprise they still say amps have no sound of their own, so opamps should all sound the same too, as long as their specs are the same. The specs tell the truth, not any golden ear.

Fortunately not all EEs think like that, like Nelson Pass or Walt Jung.


----------



## imran27

carlmart said:


> The objective vs subjective discussion is never ending when talking with most electronics engineers.
> 
> It seems they do not want really to hear or maybe are afraid that something comes up that they can't explain.
> 
> ...


I am an EE

But I have myself heard different opamps sounding different.

Heck even the bypass capacitor across the opamp power rails affects it's sound, the magnitude of change depends on the stage it is being used in (I/V, LPF, Gain)


----------



## carlmart

Of course you did! I didn't say all, just most.


----------



## imran27

Btw,

I would like other opinions as well on bypassing opamp power rails and how it affects sound with respect to different capacitors like Nichicon PW/VZ, Panasonic FM, UCC KZE, etc.

To my ears, Nichicon VZ sound like tubes, Nichicon PW sound like extremely reference and extended, point blank precision, UCC KZE sound like a middle ground of the two: like a tube+SS hybrid.

Haven't tried Panasonic FM yet.


----------



## raoultrifan

carlmart said:


> The objective vs subjective discussion is never ending when talking with most electronics engineers.
> 
> It seems they do not want really to hear or maybe are afraid that something comes up that they can't explain. [...]



Everything will be seen with an audio analyzer or a scope and a good ADC + ARTA & RMAA software. You need to compare:
- impulse response with both tested opamps
- freq. response
- freq. roll-off with square signal
- phase shift/timing with square signal
- SNR, THD, IMD, FFT harmonics as well

With some opamps 2nd or 3rd harmonic will be higher and this might have little influence on output sound. Same happens with IMD when multiple signals are applied, with some opamps there will be a "skirt" or more harmonics or higher THD and this will also influence the sound.

Some very important aspects would be: channel separation (inject audio signal only onto one channel and do some tests) and CMRR & PSRR, because a poorly designed PCB and/or schematic, combined with an opamp having less than 90dB CMRR/PSRR could create some oscillations or high frequency signals on output (lower harmonics of these signal might get into the audible range).



imran27 said:


> I am an EE
> 
> But I have myself heard different opamps sounding different.
> 
> Heck even the bypass capacitor across the opamp power rails affects it's sound, the magnitude of change depends on the stage it is being used in (I/V, LPF, Gain)



I do really like this one: http://www.analog.com/media/en/training-seminars/tutorials/MT-101.pdf. From my own experience I realized that as long as the opamp is not delivering high current output, a 0.1-1uF ceramic or MKP combined with an 10-100uF electrolytic or polymer should do well on most designs, but when speaking about output buffers, then a 10-20uF tantalum might also help, along with a 0.1-1uF ceramic or MKP (for high-power speakers buffers a combination of 0.1uF MKP with 4.7uF ceramic and 1000uF electrolytic should do well). However, it's very important to check with a scope for ringing and oscillations on V+/V- & GND, measured directly on opamp's rails; choosing higher values when bypassing an opamp might do more harm than good.


----------



## leeperry

IME Pana FR really acts as a magnifier showing the ugliness in the circuit, be very afraid coz it will hurt ^^

Some forums claim that trebles are bright, shrill yada yada but don't shoot the messenger. Wherever I put it it sounds PHAT but of course any crappy link will blow up to your ears.


----------



## FritzS

raoultrifan said:


> Everything will be seen with an audio analyzer or a scope and a good ADC + ARTA & RMAA software. You need to compare:
> - impulse response with both tested opamps
> - freq. response
> - freq. roll-off with square signal
> ...



Have you or anyone tested an audio analyzer or a scope and a good ADC + ARTA & RMAA software:  LM6171, LME49710, AD843, AD847, LT1056, LT1022, OPA602AP, TLE2071, OPA627, Supreme Sound Opamp V5 S, AD797?

In my headphone amp WNA MKII now I use AD797 with best experience. All other I listet above I tested in this amp too.


----------



## raoultrifan

I did, but in differente devices same opamps may perform very different. Most differences were noticed in SNR improvement, but sometimes when doing FFT I saw different values for 2nd and 3rd harmonics (I was usually tested for 1KHz sine).


----------



## carlmart

Unfortunately such differences will probably not show in simulations, except for THD perhaps.


----------



## raoultrifan

Signal to Noise Ratio was the most noticeable.


----------



## Rroff (Sep 27, 2018)

imran27 said:


> Btw,
> 
> I would like other opinions as well on bypassing opamp power rails and how it affects sound with respect to different capacitors like Nichicon PW/VZ, Panasonic FM, UCC KZE, etc.
> 
> ...



I've tried a lot of different capacitors both film types and aluminium electrolytics and combinations bypassing both at the op amp and obviously for filter earlier in the power supply.

Generally I don't notice much difference unless specific opamps benefit (probably due to being more stable or otherwise resulting in conditions they are happier with) but I do find that general purposes capacitors tend to result in what I call a "80s/90s" sound for want of a better way to describe it while some of the more expensive/specific purpose stuff seems to be a touch more refined and then you get some outliers that are definitely causing some degree of distortion (or the opamp just isn't 100% happy with them there).

Certain types and combinations do seem to make the sound a little narrower and some seem to widen the soundstage somehow and then there are some slight oddities like the Panasonic FM while otherwise an excellent capacitor (I use them a lot for power supply filtering) seems to result in a bit of congestion somewhere at a certain frequency or frequency and the Nichicon FG seems to have a bit of a bump somewhere around 500Hz that results in a little bit fuller sound which isn't always desirable but not necessarily a bad thing. For bypassing close to the opamp the Panasonic FC is a better bet than the FM as it seems largely transparent in impact.

Same with the old Elna Silmics that get raved about - to my ears they seem to have some kind of DSP like impact on the sound resulting in a wider and more "3D" sound but it certainly is distortion rather than truer to the original (probably somehow attenuating ~4.5KHz slightly though I'm not sure how that works via the use of a bypass capacitor) - but again not necessarily a bad thing as it can be quite pleasing for general listening.

For a "reference" like sound - very neutral if a touch "flat" but as transparent as possible I've ended up using Cornell Dubilier MLQ series in the power supply filtering stage 2x 470uf per rail and Nichicon KZ close to the opamp with 2x 220uf rail to ground and 10uf rail to rail and then some of the new WIMA 0.1uf polypropylene rail to ground at the opamp pins. For a more fun sound I swap out the 10uf for either a 0.1-0.22uf film cap or a 10uf Elna Silmic II - though it isn't earth shatteringly different.

The Nichicon PW also seem pretty good close to the opamps as you mentioned but I've not used them extensively - they've got good ESR, etc. properties in the ideal range for using in audio application like this - especially if they are sitting between a regulator and the opamp.


----------



## Mad Max (Oct 3, 2018)

SpudHarris said:


> Does anyone know what the "SQ" suffix is about on Analogue Devices?
> 
> I was searching for the TO99 version of AD712 and Farnell have this SQ version on their site for circa £33 + VAT. I don't know anything about the SQ but assume it means something like 'Superior Quality'?? Anyone have experience or knowledge of this? I love the 712 but not for that sort of cash unless there is a reason... There are several other AD chips with this suffix on Farnell. Colour me curious...


SQ should be industrial grade. Or could be commercial grade.
Different grades within "inudustrial" and "commercial" for different purposes, too. Could also be "automotive", but I think "SQ" is industrial. They've got "space grade", too.




imran27 said:


> Btw,
> 
> 
> I would like other opinions as well on bypassing opamp power rails and how it affects sound with respect to different capacitors like Nichicon PW/VZ, Panasonic FM, UCC KZE, etc.
> ...


I've tried KZE on PSU rails. I also felt that it has tube-like sound, plus great bass.

The one time I tried PW, it added hideous coloration to the midrange. Same for FM, but my Purity Audio KICAS discrete amp has big ol' FM caps in the PSU rails with none of the ugliness, so it definitely depends on how you implement the caps in the design.

There's a list of Rubycon caps that I want to play with to see if I find a worthy "successor" to my favorite, now-discontinued Rubycon capacitor.

Vishay MKP1839 160V film caps are still my favorite caps for PSU rails right on or next to opamp legs, followed by 630V and 400V WIMAs if I need to spend a little less.

I have sworn by Panasonic Oscons for PSU rails in digital circuitry for years and still do, they are the best for that.


----------



## Ivan TT

Q is for ceramic package, also SQ grade is specified for widest temperature range of all grades.
Strangely enough K grade actually has better specifications of all grades/packages:
http://www.analog.com/media/en/technical-documentation/data-sheets/AD712.pdf


----------



## max1236

Hey my xd-05 xduuo with burson v5i-d just blew out for some reason. wasnt on high gain or anything, my headphones are fine. Anyways can anyone recommend something to replace this? Don't know whats good these days.


----------



## raoultrifan

Max, I see somebody else was able to fit & play the V5-i D in there: https://www.head-fi.org/threads/xdu...tion-impressions.789886/page-53#post-13162623. However, perhaps your V5-i D was oscillating...who knows... Why don't you put back the original opamp? If it's just the output buffer, than perhaps LM4562 should do just well.


----------



## yurt28

max1236 said:


> Hey my xd-05 xduuo with burson v5i-d just blew out for some reason. wasnt on high gain or anything, my headphones are fine. Anyways can anyone recommend something to replace this? Don't know whats good these days.


If you use your portable amps for gaming and movies I'd go with usb dacs since they are now implementing hardware decoding or simply a cell phone with a really good music app. I find it funny how a circuit less than 5oz can out-perform these 5 pound power hungry amps these days.


----------



## Rick_B

I've got three V5is that are blown up in different ways....I'm not so sure about them any more...meanwhile the $17 eBay offering still plugs along.



max1236 said:


> Hey my xd-05 xduuo with burson v5i-d just blew out for some reason. wasnt on high gain or anything, my headphones are fine. Anyways can anyone recommend something to replace this? Don't know whats good these days.


----------



## carlmart

Today I was looking for a discrete option to use on CD/DVD players or DACs, and searching for the Marantz HDam discrete I found this:

http://lampizator.eu/LAMPIZATOR/FETISHIZATOR/fetishizator.html

I am not sure if it would work as well on a DAC as apparently it did on the TDA1541.


----------



## leeperry

OK guys, what the hell are those exactly? 

https://www.ebay.com/itm/Double-DIP...aptor-Converter-for-NE5532-OP275/322597406353

https://www.ebay.com/itm/Dual-Singl...-Converter-F-NE5534-AD797-OPA627/112481448568

Do they even do the same thing? I had coupons to kill so I've ordered a bunch of dual ones but can I use different chips huh?


----------



## carlmart

They are used to plug single ICs into a dual socket.


----------



## carlmart

Just found some more discrete opamps, apparently based on Marantz HDam.

https://www.ebay.com/itm/HDAM-Full-...585812?hash=item1ee48ed914:g:~RcAAOSwZrdbNvhP

Also found this, but I don't know what has that encapsulation:

https://www.ebay.com/itm/V4i-D-Dual...552618?hash=item4b4dd80faa:g:~Z8AAOSwWDRbPJBD


----------



## leeperry

That last link is most likely the same scam as https://www.jdbbs.com/thread-5699748-1-1.html


----------



## carlmart

There's nothing inside???


----------



## CoiL

Mad Max said:


> SQ should be industrial grade. Or could be commercial grade.
> Different grades within "inudustrial" and "commercial" for different purposes, too. Could also be "automotive", but I think "SQ" is industrial. They've got "space grade", too.
> 
> 
> ...


Panasonic FR are also very good in PSU filtering.
For HO/LO output caps I personally really like Panasonic FC`s... tested them against many other panasonic`s, nichicon`s (FG, FW, KW, KA, PW etc.) and also some poscaps. 
To me they give immense open soundstage and layering experience with plenty of detail and stay natural sounding, neutral sided but with hint of warmth. 
Love how FR + FC sound together. Never tried hi-end "snake oil" caps though.
Sorry for OT and maybe I was out of context, just wanted to share my experience.


----------



## LaughMoreDaily

leeperry said:


> OK guys, what the hell are those exactly?
> 
> https://www.ebay.com/itm/Double-DIP8-Dual-to-Single-Dual-OP-Amp-Opamp-Adaptor-Converter-for-NE5532-OP275/322597406353


Cool post! I didn't know double duals to dual existed. Thanks.


----------



## dB Cooper

Hey guys, relative newby here. I asked I've forwarded the below details to Burson (no response from them yet) but wanted to see if there's any feedback I can get from the folks here. Reading about some of the reliability comments of these V5i I'm hoping this is not bad news.  The PC card is an Asus Essence STX II.



> I’ve purchased from you a total of 3 of the V5i Dual Opamp chips.  I smiled when I first listened to them on the Asus card, they were well worth the money! Problem is that after having them installed for about 10 days or so, I’ve developed random pops on both the left and right channels. It’s a pop similar to what you’d hear if you put a 9v battery to a speaker a thud/pop type sound. It’s completely random and It can go hours without doing it and then will do it sporadically at a rate of once or twice a minute again on the left and right channels.
> 
> It does this on different amps so I’ve ruled that out and on different RCA cables so I’ve ruled that out. I can put the original Opamps back in the card to see if the problem goes away but at this point I thought I’d reach out to you guys to see if you’d had any type of experience with this issue on these Asus cards.



In addition to this, I can add a couple more details. The pops happen sometimes when there is no audio.  I can go hours before they happen or not happen at all. Obviously if the amp is off the pops don't happen so it's clearly an input signal issue since I've confirmed it happens  (via the card's RCA outs) on different amps.  It's never done this before I installed the Burson opamps and I've gone back and confirmedALL connections are clean and solid as well as re-seating the card.


----------



## carlmart

LaughMoreDaily said:


> Cool post! I didn't know double duals to dual existed. Thanks.


AFAIK those are two singles into one dual, like two NE5534 to work as if it was an NE5532. Is that what you mean?


----------



## LaughMoreDaily

carlmart said:


> AFAIK those are two singles into one dual, like two NE5534 to work as if it was an NE5532. Is that what you mean?


I think the link posted was 2 dual chips to turn into more power and become a better 1 dual chip? Am I confused?

Where do I find a product like that where the 2 single opamps to 1 dual are going up like a high rise instead of laying down like a road?


----------



## carlmart

Well, only the seller can answer those questions, but pairing two chips to increase the output current would be a much more specific thing than using two single chips to replace a dual one. 

But I may be wrong, of course.


----------



## yurt28

Which opa amp sounds better TI5534AP/N or Signetics 5534N and what's the difference?


----------



## carlmart

As long as they are legit 5534s. I wouldn't expect any difference in sound between them. But again. I never tried that test.


----------



## BMW Alpina

dhruvmeena96 said:


> MUSES02 is very application specific like output stages (not sure about gain stages, because it didn't fair well for me)
> MUSES01 outclasses all the OPAMPs when used in I/V stage of a DAC or an AMP(especially DAC)





dhruvmeena96 said:


> MUSES01 is something collectible and not a normal opamp. It sounds damm clean
> MUSES02 is a warm opamp and if not paired well, can turn muddy.
> 
> Hope this clear your doubts on MUSES02



Is it also safe to assume,
MUSES01 have larger soundstage, more detail, better top end sound, but less bass ?
MUSES02 have smaller soundstage, less detail, more warm in the mid and low, more bass ?

Plus you can use MUSES01 everywhere I/V, Gain, Buffer while MUSES02 is more limited in where you can ideally use them?


----------



## yurt28

From what is sounds like Muses 01 has a bump in the midrange levels to then extend to upper flat detailed highs and with that you can even add resistance to make it sound clearer, but if you can run a cpu through it that is when it really shines. Your right though muses 01 does get interesting when it's pare'd with ditto's. Muses 02 sounds cold and also extended onto the highs(best amp for bridging ne5532p).


----------



## raoultrifan

It's all in the datasheet, more than in our objective listening tests. 
Output sound is more related to surrounding components, PCB quality and design and PSU's ripple and noise, then to the op-amp itself.
MUSES01 is designed with I/V converter, MUSES02 more for use as voltage-gain, LPF or buffer, but MUSES01 works fine in other stages too.
The most important thing when rolling op-amps is to test for oscillations an how square and sine signals look like; this is the only way to check for op-amp compatibility with the circuit (unless the op-amp is recommended by device manufacturer).


----------



## BMW Alpina

raoultrifan said:


> It's all in the datasheet, more than in our objective listening tests.
> Output sound is more related to surrounding components, PCB quality and design and PSU's ripple and noise, then to the op-amp itself.
> MUSES01 is designed with I/V converter, MUSES02 more for use as voltage-gain, LPF or buffer, but MUSES01 works fine in other stages too.
> The most important thing when rolling op-amps is to test for oscillations an how square and sine signals look like; this is the only way to check for op-amp compatibility with the circuit (unless the op-amp is recommended by device manufacturer).




Hello,
I reading this thread for modifying my car audio equipment.
I already changed 14 pieces of OPA-275 op-amp inside my Zapco ASP-X4 electronic Xover with MUSES01 and the different is night and day, in term of detail, imaging, and soundstage. It's a 4 way active x-over but I only use 2 way, that is why
I only replaced 14 pieces (7 op-amp for Tweeter and 7 op-amp for Midbass channel).  I do feel that the bass freq is lower with MUSES01, that I need to have lower gain setting for the tweeter channel to match the midbass channel.
I always wonder whether using the MUSES02 for the midbass channel would make the midbass sounds better... but after reading so many review, I see that only very very few people have disappointment with MUSES01, while almost half of MUSES02 user is not too happy with the MUSES02...

My next project is to replace 11 pieces of MUSES8920 inside my Sony RSX-GS9 head unit which have _ESS Sabre_32 _ES9018S DAC._
My plan is to just replace all MUSES8920 with MUSES01 since they are both JFET... but there is always this feeling... what if the MUSES02 make the bass sounds better... what is I use the MUSES02 for the rear channel and also for the subwoofer channel. (I use the rear channel to feed the midbass channel on the Zapco ASP-X4 electronic xover)... The tweeter(front channel) will always be MUSES01...


----------



## raoultrifan

MUSES01 indeed increased soundstage and details in my Xonar Essence One DAC when used in I/V, over the default NE5532. MUSES02 did improved the sound inside the Matrix M-Stage HPA-3B, so it's all about good match and compatibility.


----------



## Nintendo Maniac (Oct 14, 2018)

I'm a relative newbie at rolling opamps, and I have just a few quick questions:


Anybody have any experience buying amps from the ebay seller "plccenter"?  I was specifically looking at this listing


A couple years back I bought a pair of LME49990MA on a single DIP8 from frugalphile for use with my Xonar DS sound card (only has a single opamp socket).  Unfortunately I've only just discovered yesterday that the opamp used for the left audio channel has distortion that sounds like clipping or a blown speaker when Windows 7's volume slider is set to 50% or greater (50% is quiet with speakers but is absolutely _defensing_ with my go-to Monoprice 9963 IEMs).  And yes, this left-channel distortion issue does not occur with the stock NE5532 opamp nor with the LME49990MA used for the right audio channel.

Considering that the LME49990 is discontinued, is there really anything I can do?  Or am I going to be stuck with needing to keep the volume below 50% (only really an issue with speakers) if I don't want to use a completely different model of opamp altogether?

If I'm left with no choice but to use a different model of opamp, then are there any suggestions for someone that _really_ enjoyed the LME49990? (as long as such an opamp is a drop-in compatible replacement that is ).


----------



## Ivan TT

AD797 seems authentic, either NOS or second hand.
Be mindful that it’s single, so you will need x2 on a single to dual adapter (Chinese Seller’s often have it backwards, dual to single).
I had similar issue with one of higher grade LM opamps, but it works fine in another circuit, go figure.
There’s a bunch of good yet timbrally different opamps out there, but it also depends on the function socketed opamp performs in your soundcard. As far as duals go AD8066 is awesome, AD826 has articulated bass, AD8620 is a bit softer and warmer, unlike AD8599, which is  sharp and modern sounding.
I don’t think it’s even possible to pick up the right one from descriptions, too many variables. I have favourite opamp-earphones combos, so use different opamps for different headphones to squeeze that elusive 5% extra synergy.
Hope it helps.


----------



## leeperry

I've missed the VSSOP train altogether, what other opamps apart from 1692 would be worth a shot please?

2*OPA1688 is da bomb on the output of O2 for that matter, 0.000 DC offset and super strong BA$$


----------



## leeperry




----------



## joeydgraffix

max1236 said:


> Hey my xd-05 xduuo with burson v5i-d just blew out for some reason. wasnt on high gain or anything, my headphones are fine. Anyways can anyone recommend something to replace this? Don't know whats good these days.



Did you use any other opamps yet? I just got my Burson V5i-d but it just goes into protect mode on my XD-05.. trying to see if theres any amps similar or better than the Burson..if you get anything you like let me know.


----------



## dB Cooper

How are you guys getting support from Burson? I've diagnosed an issue to a faulty V5i-D on my Asus STX II card. It's the one I was using in the buffer. I'd posted the symptoms a page or so ago. It's not giving me any warm fuzzy though trying to get support.  I've received one email from then (someone by the name of Alex) way back on the 10th of the month. No response to three follow up emails now.


----------



## golov17

dB Cooper said:


> How are you guys getting support from Burson? I've diagnosed an issue to a faulty V5i-D on my Asus STX II card. It's the one I was using in the buffer. I'd posted the symptoms a page or so ago. It's not giving me any warm fuzzy though trying to get support.  I've received one email from then (someone by the name of Alex) way back on the 10th of the month. No response to three follow up emails now.


@SS-Audio  Charles?


----------



## raoultrifan

dB Cooper, what’s the issue, please? I’ve tested 4 x V5i duals till now and besides compatibility issues I found no real downsides.


----------



## dB Cooper

Hey guys, hoping to get some guidance and next steps/options here.  I’ve purchased from you a total of 3 of the V5i Dual Opamp chips.  I smiled when I first listened to them on the Asus card, they were well worth the money! Problem is that after having them installed for about 10 days or so, I’ve developed random pops on both the left and right channels. It’s a pop similar to what you’d hear if you put a 9v battery to a speaker a thud/pop type sound. It’s completely random and It can go hours without doing it and then will do it sporadically at a race of once or twice a minute again on the left and right channels.




It does this on different amps so I’ve ruled that out and on different RCA cables so I’ve ruled that out. I can put the original Opamps back in the card to see if the problem goes away but at this point I thought I’d reach out to you guys to see if you’d had any type of experience with this issue on these Asus cards.
_
Hi 

Apologies for this situation but please be assured that your opamps are covered by a life-time warranty. 



It sounds like one or more of the V5i-D.



Firstly, please replace the one indicated in the photo below with your original opamp.  Does the noise now go away? Does it resolve the noise issue on one of the channels?


(the photo outlines the buffer opamp location)



Best regards,
Alex_

Okay, removed the offending opamp and it’s been working trouble free since. Does that mean that the one you had me remove is defective? I know that one is the buffer, seem like you’ve seen this type of problem before.   How do I get this one swapped?


This is the basic exchange so far, and a couple of followup emails asking for a clarification on what's the next step. I didn't see an official way to engage support on the Burson site.


----------



## raoultrifan

It probably got defective...who knows...good thing Burson will change it. Speaking about compatibility, my V5i were not compatible with my Matrix HPA-3B headamp when using low-gain, but with higher gains everything was OK.


----------



## leeperry

whenever I get tired of all this, I just roll back OPA602BP and happy happy joy joy all over again


----------



## yurt28

No, I thought I'd be using this with muses01 dipped...


----------



## SpudHarris

leeperry said:


> whenever I get tired of all this, I just roll back OPA602BP and happy happy joy joy all over again



I have to admit I do still come back to this also. Something Natural/Organic/Full in the right application. Must be an omen, check your qty of likes haha...


----------



## carlmart

Quite expensive this OPA602BP.


----------



## leeperry

Many highly knowledgeable audio ppl keep saying that any record went through armies of 5532's so what higher res opamp will allow you to hear is what nobody ever heard or cared for in the audio chain, from recording to mastering: static, distortion, hiss, you name it....and it's hard to deny tbh when going ADA4627-1B for instance, it's all about finding the right balance and 602BP does just that


----------



## FritzS

OPA602AP is in my stock too and I had tested them in my WNA MKII headphone amp. My current favorite AD797.

All tested OPAs in WNA MKII:
LM6171 (designed for), LME49710, AD843, AD847, LT1056, LT1022, OPA602(AP), TLE2071, OPA627, Supreme Sound Opamp V5, AD797


----------



## leeperry

797 cannot be rolled blindly, it's not even unity gain stable IIRC hence its SS will be very colored, trebles quite shrill and it'll get super hot too.

when rolling blindly it's better to go for highest grade as that improve stability somewhat due to higher tolerances, easy to hear with LT1028/1028A & OPA627A/B. Hard to believe they're even the same chips and they were all sourced from authorized dealers.


----------



## carlmart

What do you mean by "rolled blindly"?


----------



## Rroff

carlmart said:


> What do you mean by "rolled blindly"?



Some opamps have very specific circuitry requirements otherwise they become unstable so you can't just blindly use them if you don't understand how the circuit they are in works.

For instance some circuits use capacitors in the feedback loop to reduce or remove any gain on certain frequency ranges but if the opamp isn't stable i.e. isn't unity gain stable with that setup all kinds of undesirable things can happen even potentially the opamp killing itself.

797 IIRC is pretty demanding on the placement and values of capacitors close to its power supply pins otherwise you tend to get a lot of problems with it especially if you are using it in a DIY fashion on prototype/breadboard, socket adapters or non-soldered.


----------



## FritzS (Oct 24, 2018)

I use some caps near the OPA power-pins. The schema and the board is designed for LM6171 - this OPA is a high-speed “diva“!


----------



## carlmart (Oct 24, 2018)

Rroff said:


> Some opamps have very specific circuitry requirements otherwise they become unstable so you can't just blindly use them if you don't understand how the circuit they are in works..



OK, I agree with that. Very fast opamps can be tricky, for isntance

.





> For instance some circuits use capacitors in the feedback loop to reduce or remove any gain on certain frequency ranges but if the opamp isn't stable i.e. isn't unity gain stable with that setup all kinds of undesirable things can happen even potentially the opamp killing itself..



Voltage feedback opamps can't have caps in feedback loop. Poorly designed pcbs can be tricky.

.





> 797 IIRC is pretty demanding on the placement and values of capacitors close to its power supply pins otherwise you tend to get a lot of problems with it especially if you are using it in a DIY fashion on prototype/breadboard, socket adapters or non-soldered.


 Soldering bypass caps, at least 1uF if possible, directly on the chip supply pins and also bypassing between supply pins with another caps, should tame most (if not all) tricky opamps. Temp rise on the chip may be caused by oscillation. Walt Jung's superregulator was marginally stable when using the AD797, and there were experienced people working with it.


----------



## Rroff

Technically I guess the caps aren't in the feedback loop as their purpose is to act as a filter bypassing to ground rather than providing feedback. But yeah some opamps can be extremely picky about compensation capacitors and the like.


----------



## leeperry (Oct 24, 2018)

Long story short you need some serious technical background to hear what 797 can truly offer, rolling it like a piece of lego is idiotic at best.


----------



## Ivan TT (Oct 24, 2018)

I had misbehaving 797 in my DSD (although it worked just fine in Z3), both A and B grades, SOIC on adaptor, gain of 1: sweeping noises, RFI, overheating.

After trying everything suggested in datasheet, eventually solved the problem by adding RC filter tuned to about 150kHz on the opamps output (and buffer's input).

I disagree that 797's rolling is "idiotic" (or maybe just disagree with strong language used), in most cases it will work just fine, but sometimes needs minor tweaks to the circuit.

Strangely enough is 797 effectively biased in class A due to oscillation and I kind of liked the sound signature, it was a bit more vivid and involving.


----------



## leeperry

Scott Wurcer, inventor of AD797 made very clear that blind rolling it was not a smart idea, like not at all. We had a long thread about rolling opamps on diyaudio and the man is not kidding.


----------



## carlmart

leeperry said:


> Scott Wurcer, inventor of AD797 made very clear that blind rolling it was not a smart idea, like not at all. We had a long thread about rolling opamps on diyaudio and the man is not kidding.



Any final recommendation list on how to implement it? That would be useful.


----------



## raoultrifan

Perhaps the bypassing recommendations from https://www.analog.com/media/en/technical-documentation/data-sheets/AD797.pdf might help.

@*Ivan TT*, the low-pass filter was created at AD797 output? However, given the highly oscillations, I would probably remove it if I were you and replace it with something else; it just sounds safer to swap it for something else. BTW, I wonder how the ground was done there...or if there's any ground plane on the PCB.


----------



## Ivan TT (Oct 25, 2018)

raoultrifan said:


> the low-pass filter was created at AD797 output?


Yes.


raoultrifan said:


> However, given the highly oscillations, I would probably remove it if I were you and replace it with something else; it just sounds safer to swap it for something else. BTW, I wonder how the ground was done there...or if there's any ground plane on the PCB.


Well, since I don't have oscillations anymore I don't need to remove it, it works and sounds just fine (although I have other opamps in my DSD atm, namely AD8065 and AD825 purely for synergy with my DIY IEMs).

As I mentioned before, I used every trick from AD797 datasheet, at some stage I had 4 bypass 100nf caps soldered directly onto AD797 power pins + 2 on DIP8 power terminals AND 50pf from pin 8 to output, made no difference whatsoever, sweeping noise and RFI  and heat were _exactly_ the same. 

But Zishan DSD has it's processor literally touching opamp, so I'm not to surprised that AD797 was misbehaving as I don't think it's really RFI hardened and is sensitive to UHF noise.

RC filter on the output solved all of it and filter's cutoff is way outside of the audible range to be of concern and I used MELF resistors and PPS caps, so I'm quite happy, even if this approach is not in the datasheet.


----------



## bogginhead

Would I have to have two Muses03 if I wanted to use it in a Fiio E12 DIY since it's a single?  Or could I just use one with some kind of adapter?


----------



## Rroff

carlmart said:


> Any final recommendation list on how to implement it? That would be useful.



Problem is it isn't always something that can be sorted by just adding or removing a few components - some of these opamps ideally require soldering with very short lead lengths to the components around them and attention paid to the implementation of the traces around them to avoid parasitics, etc.

The 797 has a fair amount of detail somewhere towards the end of the datasheet IIRC on best practises and so on but it isn't exhaustive. Bypassing the power supply directly on the pins with some small capacitors helps a lot.


----------



## raoultrifan

I'm successfully using 2 x AD797 in one of my Burson PLAY combo DAC/headmp units, in the pre-amplification stage (gain or voltage amplification), just before the output stage. I have no oscillation, no overheating or anything suspicious; had this tested with oscilloscope.
I have a "feeling" that PCB board layout, design and quality is with it counts more, of course...with enough decoupling around the op-amps, combined with a low-noise and very well regulated power supply.


----------



## FritzS

Ivan TT said:


> Yes.
> 
> Well, since I don't have oscillations anymore I don't need to remove it, it works and sounds just fine (although I have other opamps in my DSD atm, namely AD8065 and AD825 purely for synergy with my DIY IEMs).
> 
> ...



I use Evox Rifa PHE 450 100nF near the socket and bypassed them with WIMA FKP2 10nF/63V
I don't use the recommend 50pf cap between pin 6 (out) and pin 8; I don't use the 20pf in NFB too.

I have no measure equipment at this time - but the sound result is very well! I hear with AKG K812 - this headphones don't forgive even the smallest of shortcomings.


----------



## Nintendo Maniac (Oct 25, 2018)

I'm going to be ordering one of those fancy dual-mono to single-stereo DIP8 adapter things that were linked previously in this thread, but currently I actually don't have any mono op amps (I plan on getting a couple AD979 sometime in the future, but they're costly enough to not be an impulse-buy).

Are there any suggestions on an inexpensive (maybe just a couple bucks?  The adapter is only $3.47) decently-good NE5532-compatable mono opamp just so I can make sure that this adapter is functioning alright?  Outside of the stock NE5532, All I have right now is an LME49990 and an AD825 (both of which are dual-mono soldered onto a single stereo DIP8).


*EDIT:* And it should preferably be a solderless DIP8 form-factor opamp.


----------



## Ivan TT

Nintendo Maniac said:


> I'm going to be ordering one of those fancy dual-mono to single-stereo DIP8 adapter things that were linked previously in this thread, but currently I actually don't have any mono op amps (I plan on getting a couple AD979 sometime in the future, but they're costly enough to not be an impulse-buy).
> 
> Are there any suggestions on an inexpensive (maybe just a couple bucks?) decently-good NE5532-compatable mono opamp just so I can make sure that this adapter is functioning alright?  Outside of the stock NE5532, All I have right now is an LME49990 and an AD825 (both of which are dual-mono soldered onto a single stereo DIP8).


AD8065, if it works you get yourself a very decent sounding dual!


----------



## Nintendo Maniac (Oct 25, 2018)

Ivan TT said:


> AD8065, if it works you get yourself a very decent sounding dual!


The adapter is only $3.47, and two of such opamps in a DIP8 form factor costs over 10 bucks even from Chinese ebay sellers...heck those same Chinese ebay sellers have the dual mono on a single DIP8 variant for only like a single dollar more!


----------



## Ivan TT

Nintendo Maniac said:


> The adapter is only $3.47, and two of such opamps in a DIP8 form factor costs over 10 bucks even from Chinese ebay sellers...heck those same Chinese ebay sellers have the dual mono on a single DIP8 variant for only like a single dollar more!


You need SOIC8 variant, does arrow deliver to your country?
https://www.arrow.com/en/products/ad8065arz/analog-devices
Having said that if it’s for practice only, get 2 opa627 from eBay, they are like $3 posted and even if they are fakes (most likely) no big loss.


----------



## Nintendo Maniac (Oct 25, 2018)

Ivan TT said:


> You need SOIC8 variant


Doesn't that still require soldering though?

For example, isn't this SOIC8?: http://www.keterex.com/img/soic-8.jpg

Don't I need something like this instead (presumably DIP8)?: https://www.diy-shop.ch/179-thickbox_default/20stk-timer-ic-ne555-dip8.jpg


----------



## leeperry (Oct 26, 2018)

English, do you speak it? This adapter is not 2 singles to 1 dual, it's 2 dual to 1 dual......unsure of details but one is used as extra buffer apparently.

I got a bunch of those here with me but still afraid to try them, much like my fake LT1028ACH.


----------



## Nintendo Maniac (Oct 26, 2018)

Oh I'm a derp.  Good catch nevertheless as I haven't actually bought it just yet (looking at my previous posts, it seems I misspoke and said I did).

Well, I _did_ say that I'm a relative newbie at rolling opamps.


----------



## Nintendo Maniac

Apologies for the double-post, but it doesn't look like Head-fi lets you delete posts...

I believe something like the following is what I'm actually looking for?

https://www.ebay.com/itm/172990056225

https://www.ebay.com/itm/172677868865

And since they're just passive boards without any sort of funky electrical conversion stuff, I can't imagine them hurting anything outside of it actually being assembled incorrectly.


----------



## LaughMoreDaily (Oct 26, 2018)

Ivan TT said:


> AD8065, if it works you get yourself a very decent sounding dual!


What does the AD8065 have a problem working with? Zishans? Walnuts? Or...?


----------



## LaughMoreDaily

Nintendo Maniac said:


> heck those same Chinese ebay sellers have the dual mono on a single DIP8 variant for only like a single dollar more!


Do you have a link to the DIP Dual Mono (2) to Single Dual (1) VERTICAL?


----------



## Nintendo Maniac

LaughMoreDaily said:


> Do you have a link to the DIP Dual Mono (2) to Single Dual (1) VERTICAL?



AFAIK tell vertical ones don't exist.


----------



## LaughMoreDaily

Nintendo Maniac said:


> AFAIK tell vertical ones don't exist.


Sad... those are the only ones that work in a Walnut/Zishan. I wonder if the Horizontal ones will work in a Jazz Headphone Amp?


----------



## Ivan TT

LaughMoreDaily said:


> What does the AD8065 have a problem working with? Zishans? Walnuts? Or...?


Nah, I was talking about soldering it onto adaptor, if soldering works.
As to the op amp itself (and it’s dual version, AD8066) 8065 is one of the best, clean, clear and transparent.


----------



## The Chief

Hi 



 
*dhruvmeena96*
*I have 2 more questions about resistors: Did you twell your robot to take care about the direction the resistors were soldered in? I cannot stress enough the meaning of this detail . I could hear differences at any resistor I ´ve changed, no matter if that was in an op amp or in a guitar amp.*
*second, you kindly gave the rhopoint weblink of your zfoil precision smd resistors. Unfortunately that link seem to be killed  at rhopoint.com. So could you please make a new link?   When I compared TX2575 wirh rhopoint wirewounds, I din´t like the little more steril sound of the TX, to my ears, I like a little dirt, and the technical best solution is very often not what I like to hear. For me, it´s about subjective sound impression. But I´d like to listen to what you use... Nothing can replace an own listening !!! *


----------



## CoiL

Any good upgrade recommendations for dual-opamp (any socket version is ok) instead NE5532AD ? 
I couldn`t get Burson V5i-D working instead of it as seems power feed is too low to keep V5i-D running.


----------



## raoultrifan

For what stage? In what device?


----------



## Nintendo Maniac (Nov 6, 2018)

LaughMoreDaily said:


> Do you have a link to the DIP Dual Mono (2) to Single Dual (1) VERTICAL?



On my own Xonar DS, the horizontal version of the adapter I linked to would be too wide as well and run into some nearby capacitors.  However, one of my recent op amps came with a sort of riser that looks like it would make this horizontal dual adapter actually fit and rest _above_ the aformentioned capacitors.

Similarly, it looks like the adapter in question actually comes with two (pictured below), but while normally they're meant to be actually used to raise the op amps above the adapter board, I wonder if you couldn't instead put the op amps directly onto the board and then put one or more of the risers on the single bottom side of the entire adapter.




Now I've no idea if is such a thing would fit into your device, but it may nevertheless be an option.


----------



## LaughMoreDaily

Nintendo Maniac said:


> However, one of my recent op amps came with a sort of riser that looks like it would make this horizontal dual adapter actually fit and rest _above_ the aformentioned capacitors.
> 
> Similarly, it looks like the adapter in question actually comes with two (pictured below), but while normally they're meant to be actually used to raise the op amps above the adapter board, I wonder if you couldn't instead put the op amps directly onto the board and then put one or more of the risers on the single bottom side of the entire adapter.
> 
> ...


I'm going to try that, thanks for the advice. I think I may have thought about that before but always wondering if it would cause some kind of noise or disruption because you would think that would happen the more opamp risers you use? At least I think like that. It's best to have the opamp on the board ideally... I wonder what it would be like to use 2 or 3 or 4 risers to be able to use opamps in a Walnut/Zishan music player? I will try that but I'll have to order some first. 

Maybe someone here has already tried and can let us know how it went?


----------



## CoiL

raoultrifan said:


> For what stage? In what device?


Darn... totaaly forgot to add this...

Device is Aune T1 with capacitors mod and opamp I would like to try change is headphone amp board NE5532AD dual-channel opamp with swichable gain (+10db (~500mA) & +16db (~1000mA) ).





Though, in current setup with Siemens/Halske E88CC goldpin tube it sounds totally great. Just wondering if I could get more SQ out of HO.


----------



## raoultrifan

I assume the NE5532AD is used in gain-stage/voltage-amplification, so any audio opamp & unity-gain stable should do just well here: OPA1612, LME49720/LM4562, MUSES8820/8920/01/02, BURSON SS V6 etc. It would be interesting to find out the voltage rails, though given the output voltage I guess would be +/-12V.


----------



## CoiL (Nov 8, 2018)

raoultrifan said:


> I assume the NE5532AD is used in gain-stage/voltage-amplification, so any audio opamp & unity-gain stable should do just well here: OPA1612, LME49720/LM4562, MUSES8820/8920/01/02, BURSON SS V6 etc.* It would be interesting to find out the voltage rails, though given the output voltage I guess would be +/-12V.*


Will measure it and report back. Anyway, powering the V5i-D was problem.

EDIT:

Measured between pin 4(V-) and pin8 (V+) with NE5532 and got *30.2V* ! No load, 0 gain. Under load with music, same.
Should be real as power brick is with voltage swing 15V-0-15V.

I`m confused. Why didn`t V5i-D work? I installed it right way for sure.


----------



## raoultrifan

You're not the only one that found incompatible equipment for V5i-D. I got a similar issue when tried to roll it in my Matrix HPA-3B headamp. V5i is a great opamp, but it's just not compatible with everything out there, so we just need to live with this and swap it for a different opamp.


----------



## CoiL (Nov 8, 2018)

Will try to re-solder V5i-D again... just to be sure I didn`t mess anything up and soldering points are great. Pity if it doesn`t work.

EDIT:

Btw, wanted to ask if installing 2x NE5534 with 2xSingle-to-1xdual adapter will provide SQ improvement over NE5532AP dual-channel chip ?

EDIT2:

Maybe NE5532 being bi-polar in Aune T1 is problem for V5i-D ?

Also, what do You guys say about changing Aune T1 DAC differential opamp which is OPA2134 if I remember correctly? Would it have any useful SQ improvement?


----------



## yurt28

Does anybody know how Max293CPA dippers work? I can't get these 8 pin dips to pass through anything without over heating.


----------



## CoiL (Nov 9, 2018)

CoiL said:


> Device is Aune T1 with capacitors mod and opamp I would like to try change is headphone amp board NE5532AD dual-channel opamp with swichable gain (+10db (~500mA) & +16db (~1000mA) ).
> 
> 
> 
> ...



Ok, added those DIP8 dual-channel cheapo opamps in my shopping basket:

LM358N
NJM4560D
LM4562NA
LME49720NA

any of them that sounds total crap and should scrap off the list?

One more question - can I use ADA4084-2 in that location?
____________________________________________________________________________

EDIT:

Ok, since I`m not so experienced opamp-roller like most users in this thread seem to be, I`ll better ask some important questions than shoot off blindly into those cheap opamps:

What are THE MUST specifications (for example does it have to be bipolar? GBP must be 10MHz?  RRIO is OK?) for an opamp in my case with Aune T1 headamp board implementation ?

Headamp board transistors are B649 / D669
Stock headamp board opamp is NE5532
headamp board has 3 different gain modes - +0dB / +10dB / +16dB
NE5532 measures between pin 4(V-) and pin8 (V+) 30.2V

I just thought that instead experimenting with cheapo opamps which probably give no SQ improvement, I rather buy something good with money I would spend on these.
So far I`m interested about these:

1) ADA4084-2ARZ-R7
https://eu.mouser.com/ProductDetail/Analog-Devices/ADA4084-2ARZ-R7?qs=BpaRKvA4VqECXiuuCyMa3A==

2) AD8599ARZ
https://eu.mouser.com/ProductDetail/Analog-Devices/AD8599ARZ?qs=sGAEpiMZZMvtNjJQt4UgLalm6EXZly/yucPtlNMTDKM=

3) ADA4004-2ARZ
https://eu.mouser.com/ProductDetail/Analog-Devices/ADA4004-2ARZ?qs=sGAEpiMZZMvtNjJQt4UgLalm6EXZly/yp89fjq9heu8=

4) AD8676ARZ
https://eu.mouser.com/ProductDetail/Analog-Devices/AD8676ARZ?qs=sGAEpiMZZMvtNjJQt4UgLalm6EXZly/yBkniS4BODf0=

5) AD8672ARZ
https://eu.mouser.com/ProductDetail/Analog-Devices/AD8672ARZ?qs=sGAEpiMZZMvtNjJQt4UgLalm6EXZly/y8vNj%2bbcMPN0=


...don`t slap me please


----------



## raoultrifan

CoiL said:


> [...]
> Btw, wanted to ask if installing 2x NE5534 with 2xSingle-to-1xdual adapter will provide SQ improvement over NE5532AP dual-channel chip ?



Crosstalk might be better, so soundstage could increase, but only theoretically, because today's opamps already have an extremely good channel separation by default (our ears are very comfortable with a channel sepparation of 70dB for freqs. lower than 10KHz and >50dB for freqs. higher than 10KHz).



CoiL said:


> [...]
> Maybe NE5532 being bi-polar in Aune T1 is problem for V5i-D ?



Don't think it matters. You should leave with the fact that V5i-D is incompatible with Aune T1. 



CoiL said:


> [...]
> Also, what do You guys say about changing Aune T1 DAC differential opamp which is OPA2134 if I remember correctly? Would it have any useful SQ improvement?



You should post a layout of something here...sort of a schematic. Where is this OPA2134 located? Is it in I/V stage?
Try a MUSES8920 instead or an OPA1612.


----------



## CoiL (Nov 10, 2018)

Thanks for advice. I think Iwill leave dac differential opamp as it is for now and try to improve headamp board.
Atm I need advice if those opamps are compatible instead NE5532 in that application:


CoiL said:


> Headamp board transistors are B649 / D669
> Stock headamp board opamp is NE5532
> headamp board has 3 different gain modes - +0dB / +10dB / +16dB
> NE5532 measures between pin 4(V-) and pin8 (V+) 30.2V
> ...


----------



## FritzS

NE/SA/SE5534 - in old schemas there gives an trick to give them more BIAS in output driver. As far as I know a resistor to pin_5 (8, 1), but I don't found any hints in Internet.
I saw this in a DIY schematic a long time ago, but can't find this DIY magazine anymore.

http://www.onsemi.com/PowerSolutions/product.do?id=NE5534


----------



## CoiL (Nov 10, 2018)

I made a little specs comparison table:





Which ones to choose?
AD8672ARZ & AD8676ARZ both seem promising by specs and should work... or not?
Previously recommended OPA1612 looks nice too but higher slew rate & 80MHz make it questionable for me...


----------



## raoultrifan

Please review the datasheet, in some places voltage rails are having +/- in font. Also, AD8599 can be powered from +/-15V with an absolut max. of +/-18V.

AD8599 surclasses the AD8672; it can also be used in I/V stage with great results, I did it in PLAY and it was perfect match (also, see Vaughan DAC).

OPA1612 is great too, it doesn’t oscillate if PCB design is right and decoupled according datasheet.


----------



## CoiL (Nov 10, 2018)

So, You`re saying I should just go for AD8599 instead of buying&trying AD8672 / AD8676 / ADA4084 ?
Any idea about AD8599 output current per channel? Couldn`t find it...


----------



## raoultrifan

They’re not expensive, give’em all a try, later you’ll decide which one’s the winner.

You could also try 2xAD797 with single-dual adapters, they’re the less noisiest from this group.


----------



## CoiL

Ok, decided & bought AD8599ARZ first to try... will report back soon. Hope I don`t run into any issues like with V5i-D.


----------



## raoultrifan

You won't come into issues, well...unless there's something wrong inside the Aune design or PCB has faulty ground plane (I'm sure it's not the case).

Looking further for your test.


----------



## yurt28

What's this one?


----------



## CoiL

4x N5534 (text on chips looks like this)? no idea.


----------



## yurt28

The bump in the frequency is just amazing pretty soon caps with jfet resistors will be changed out and man Power Power Power. Yes muses01 bridged to Ne5534p and Ne5532p for output. No Wima filters except what's raw on its circuit board I think miniK72's or p54's?


----------



## CoiL

Is this thingy available anywhere?


----------



## yurt28

Does anybody know of any Maxim amps that can be used for 8 pin dipping? I've tried 1 and cannot get any sound to pass through it i think this one I've used may be for Pre-Dac filtering?


----------



## yurt28

CoiL said:


> Is this thingy available anywhere?



Enjoy the beauty of searching the web China claims to have 9999 in stock lol


----------



## raoultrifan

yurt28 said:


> What's this one?


99% FAKE MUSES01, sorry mate. 
For the additional 1% you might need to take a decent close-up only with "MUSES01".


----------



## SpudHarris

ADA4627-1... 

This in the right application is just awesome. Using this in the headphone section of Beresford TC7520 and OMG!! Just so realistic.


----------



## CoiL (Nov 20, 2018)

CoiL said:


> Darn... totaaly forgot to add this...
> 
> Device is Aune T1 with capacitors mod and opamp I would like to try change is headphone amp board NE5532AD dual-channel opamp with swichable gain (+10db (~500mA) & +16db (~1000mA) ).
> 
> ...





CoiL said:


> Will measure it and report back. Anyway, powering the V5i-D was problem.
> 
> EDIT:
> 
> ...





CoiL said:


> Ok, added those DIP8 dual-channel cheapo opamps in my shopping basket:
> 
> LM358N
> NJM4560D
> ...





CoiL said:


> I made a little specs comparison table:
> 
> 
> 
> ...





CoiL said:


> Ok, decided & bought AD8599ARZ first to try... will report back soon. Hope I don`t run into any issues like with V5i-D.





raoultrifan said:


> You won't come into issues, well...unless there's something wrong inside the Aune design or PCB has faulty ground plane (I'm sure it's not the case).
> 
> Looking further for your test.



Just finished installing AD8599ARZ into Aune T1 headamp board...





Initial impressions:
1) INSANE DETAILS! Never thought I could get more detail (micro) and separation/layering/transparency out of modified T1 + Siemens E88CC tube.
2) At first little "bright" sided but really very clean sound. I wonder if this chip will "calm down" littlebti after some playtime?
3) My Fidelio X1 hasn`t sounded so balanced with this setup. Just wonderful!

But another note - stock NE5532 is not bad at all. Improvement with AD8599ARZ is not like night-and-day. If not hardcore modder/audiophile, then stock chip is totally OK too (Aune has done NE5532 implementation very well in T1 imo).

Will soon try out 2 more opamps instead NE5532/AD8599 and make socket roll-able.
Any recommendations beside/instead OPA1612AID?


SpudHarris said:


> ADA4627-1...
> This in the right application is just awesome. Using this in the headphone section of Beresford TC7520 and OMG!! Just so realistic.


Will add this into list and look more about specs too.
Naah... won`t bother messing with 2x1channel, I decided.

Also... still thinking about changing DAC differential opamp but have to do more research about what will work there as potential upgrade over OPA2134 (btw, haven`t tested V5i-D in that spot yet, so no idea if it will fail to work there too).


----------



## Zephead

Just been playing with swapping opamps on my SMSL sap ll Pro. Standard is OPA2604. 

OPA2107, too bright, lacking bass. 
LM4562, doesn't work with this amp, low, dodgy sounding output.
LT1364, no output at all
OPA2227, no better than the OPA2604
OPA2228 - this is the one! Bass as good as the 2604 but tighter and better top end. Mid's about the same. Better instrument separation. 

I'm not an audiophile and my ears are 53 years old so these are just my subjective impressions using the opamps I had lying around. (I have a Little Dot I+ as well (LT1364 with Voshkod valves)

I'm going to be buying a Magni 3 next month but I'm not convinced it will beat this SMSL with the OPA2228. If it doesn't it's going back but I'm hoping it does.


----------



## raoultrifan

https://www.reddit.com/r/ZReviews/comments/4vtsae/going_from_smsl_sap_ii_pro_to_schiit_magni_2_uber/

The above link is explanatory, indeed Magni should be better than SMSL sap ii Pro.

P.S.: I don't agree with latest comment from the above link: SPL of 90dB is pretty high *average *listening level, not absolute maximum listening level. avg. of 90dB SPL means between 100-110dB max. SPL, depending of the dynamics of the music. Basically, if a headamp is not able to drive our cans to 110-115dB SPL, then it's a "no go", even if we don't really use these very high levels.


----------



## Zephead

Sounds like the Magni will be great with my HE400i then (picked a pair up for £180 when the Sundara came out). Also gives me headroom for a future purchase of T50RPs. I like tinkering so a pair is almost definitely a future purchase.


----------



## CoiL

Zephead said:


> OPA2228 - this is the one! Bass as good as the 2604 but tighter and better top end. Mid's about the same. Better instrument separation.


https://eu.mouser.com/ProductDetail...GAEpiMZZMvtNjJQt4UgLd0UjFS%2bBnCWmziT7Q5S7G4=

Looking at specs, wondering if this can be used also in Aune T1 instead NE5532 ?
I`ve heard good things about OPA2228 in Cmoy.


----------



## Rroff

OPA2228 is great - not a detail monster but you never feel like detail is missing and hence flattering on so-so bitrate MP3s, etc. very nice easy listening opamp with smooth midrange and somewhat tube like bass and top end. I mean it is probably far from transparent but a pleasure for enjoying the music.


----------



## Ivan TT

CoiL said:


> 2) At first little "bright" sided but really very clean sound. I wonder if this chip will "calm down" littlebti after some playtime?


Nope, that would be its "signature" sound.
Try AD8066 (NB maximum supply voltage is +/-12V) for same level of details less brightness.


----------



## CoiL

Ivan TT said:


> Nope, that would be its "signature" sound.
> Try AD8066 (NB maximum supply voltage is +/-12V) for same level of details less brightness.


So, to get it working, I must use potentiometers on both channels or something? I have +-15V power to feed it.
Btw, I left it playing for few days without listening and it seems to be somewhat "tamed".


----------



## Rroff

I wouldn't use potentiometers to drop the voltage - AFAIK you'd have all the problems of a resistor divide with the potential for it to become unbalanced, etc. ideally you'd need linear regulators to drop the voltage but you'd also need some capacitors, etc. if you did that even with the use of something like a LM2940/2990-12 pair.


----------



## spacequeen7

Enjoying this two so far Sonic Imagery Labs 994Enh-Ticha and SS3602


----------



## carlmart

Ivan TT said:


> Try AD8066 (NB maximum supply voltage is +/-12V) for same level of details less brightness.



How does it compare, in audio qualities, with the OPA1612?


----------



## Ivan TT

carlmart said:


> How does it compare, in audio qualities, with the OPA1612?


Better soundstage, better detail and less veil, but bear in mind that I am an AD fanboy 
OPA1612 also just a tad harsh to my liking, while 8066 is spot on.
Supply current is x2 higher than OPA, so expect reduction of battery life in portable applications, but most likely 8066 has class AB output stage, nice!


----------



## carlmart

This application will not be for battery powering. Just normal regulated +/-15v or more power supply.

And it will not be to drive a headphone either, but for a DAC's line output. I would prefer to have a class A output too, perhaps with the usual trick of a resistor or ccs, from output to to V+


----------



## Ivan TT

carlmart said:


> This application will not be for battery powering. Just normal regulated +/-15v or more power supply.
> 
> And it will not be to drive a headphone either, but for a DAC's line output. I would prefer to have a class A output too, perhaps with the usual trick of a resistor or ccs, from output to to V+


OK, AD8066 maximum supply is +/-12V
I my case opamps don’t drive headphones directly either (opamps are followed by a buffer), so pretty much the same setup as in line out driving hi-z input.


----------



## CoiL (Dec 3, 2018)

Rroff said:


> I wouldn't use potentiometers to drop the voltage - AFAIK you'd have all the problems of a resistor divide with the potential for it to become unbalanced, etc. ideally you'd need linear regulators to drop the voltage but you'd also need some capacitors, etc. if you did that even with the use of something like a LM2940/2990-12 pair.


Yeah, I thought it will not be so easy. Will still go for OPA1612 first and hear the difference between AD8599ARZ and NE5532.


----------



## carlmart

Ivan TT said:


> OK, AD8066 maximum supply is +/-12V
> I my case opamps don’t drive headphones directly either (opamps are followed by a buffer), so pretty much the same setup as in line out driving hi-z input.



AFAIK, a buffer shouldn't be necessary to drive short cables, from source to preamp or preamp to power amp. 

That's why I would like having a chip biased to class A at least, being that all opamps are class AB by internal design. Is there anyone that is not?


----------



## Rroff

While I never looked at crossover distortion, etc. on a scope in this context aside from 1-2 older opamps I've never been able to discern any difference between class AB and biasing to class A (with an advanced cascode) by ear with any reasonably modern opamp.

The AD8066 can be quite veiled in some applications - more so than the OPA1612 IMO but in other applications you can pretty much eliminate 90+% of that especially in circuits that use some form of active ground setup for some reason where the AD8066 seems to benefit - if you _really_ want to hear what the AD8066 is capable of build a pseudo-balanced (or fully balanced) amplifier with an AD8066 per channel in "push-pull" type configuration and drive something like the HD600s via a balanced cable.

While "burn-in" is a contentious one and I don't generally notice it with opamps I do find the OPA1612 appears to benefit a lot from a period of "burn-in" out the box there is a slight harshness and colouration that goes away with use.

For want of a better understanding of it the AD8066 seems to better preserve "directionality" somehow at lower frequencies if such exists in the original music - I don't really understand it but that seems to be somewhere along the lines of what is going on and why it seems to have a subjectively better soundstage than the OPA1612 and gives it a somewhat different bass experience to the average opamp.


----------



## carlmart

I have nothing against headphones, after all they were my most important tool in my recording years, besides the Nagra and the Sennheiser microphones!

But I think a good amplifier + speaker system, on a good listening space, is hard to beat by any headhone in audio qualities. 

Rarely do I listen to headphones nowadays, maybe during flying or travelling by bus, so my concern is mostly for line amplification. Demands are less than headphone amps, you don't really need output transistors, besides those inside the IC. 

What do you mean by "active ground"? The one you have to make when using single supplies, like batteries?


----------



## Ivan TT

carlmart said:


> AFAIK, a buffer shouldn't be necessary to drive short cables, from source to preamp or preamp to power amp.
> 
> That's why I would like having a chip biased to class A at least, being that all opamps are class AB by internal design. Is there anyone that is not?


I mean in my set up AD8066 drives buffer input, while buffer drives headphones, so AD8066 sees high impedance (similar to line input of a HP amp), not low-z headphones.

These are cool for class-A biasing:
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/252135197507


----------



## Rroff (Dec 4, 2018)

carlmart said:


> What do you mean by "active ground"? The one you have to make when using single supplies, like batteries?



I'm talking more in the "3 channel active ground" kind of implementation (like the Pimeta https://tangentsoft.net/audio/pimeta2 ) rather than just using an opamp or similar just to set a virtual ground reference though there are a lot of drawbacks especially in terms of noise to that approach but the AD8066 seems to work really well in terms of producing something that is pleasing to listen to even if from an engineering perspective there are a few negatives to the amp design itself.

I built an amp (somewhat along the lines of the PBA https://www.head-fi.org/threads/pseudo-balanced-amplifier-pba.553236 ) that uses one AD8066 per audio channel, with a fully isolated ground per channel, with the headphone drivers sitting across the outputs of the two amps in the package and it takes the AD8066 to another level again.


----------



## raoultrifan

For a very good representation of what active ground means and why would this be better than regular 2-channels headamps, Dr. Meier Corda has a dedicated webpage here: http://www.meier-audio.homepage.t-online.de/grounds.htm.


----------



## carlmart

Rroff said:


> I'm talking more in the "3 channel active ground" kind of implementation (like the Pimeta https://tangentsoft.net/audio/pimeta2 ) rather than just using an opamp or similar just to set a virtual ground reference though there are a lot of drawbacks especially in terms of noise to that approach but the AD8066 seems to work really well in terms of producing something that is pleasing to listen to even if from an engineering perspective there are a few negatives to the amp design itself.



The Pimeta does implement a virtual ground with an opamp, the TLE2426, only more compactly packed. For headphone drivers it's a simpler powering system, certainly better than using two batteries in portables, using the mid junction as ground. Those batteries may discharge differently and cause power unbalances. The other way is to use a DC-DC supply to generate the +/- voltages. Using the TLE is a simpler way to do that that may work on such circumstances. 




> I built an amp (somewhat along the lines of the PBA https://www.head-fi.org/threads/pseudo-balanced-amplifier-pba.553236 ) that uses one AD8066 per audio channel, with a fully isolated ground per channel, with the headphone drivers sitting across the outputs of the two amps in the package and it takes the AD8066 to another level again.



The additional circuit for the ground amplifiers allows more current to be used, which is the limitation of the TLE and essential for hungry headphones. 



raoultrifan said:


> For a very good representation of what active ground means and why would this be better than regular 2-channels headamps, Dr. Meier Corda has a dedicated webpage here: http://www.meier-audio.homepage.t-online.de/grounds.htm.



Balancing a signal can be interesting, particularly if the grounding can't be kept absolutely zero. You could use a balancing chip to feed the separate drivers with more isolation, or a transformer. But of course, you would need to recable the headphones. But most quality headphones that I know of already have two-wires for each driver, that only get together on the connector. There wouldn't be any-rewiring.


----------



## raoultrifan (Dec 4, 2018)

I've measured the ground-wire for most of my cans and I found a higher resistance that the hot-wires, which kinda sucks to me. I immediately understood that re-wiring is not snake-oil for some cans (AKG K701, Beyerdynamic DT880 a.s.o.).

On the 3-channel amplifiers there's no need to do any rewiring, as long as a good cable is used.


----------



## carlmart

I think it's a worth a try and listening, which in the end seems to me as the best possible test. Many electronics engineers will probably disagree.


----------



## raoultrifan

I'm sure all EE's will agree that active ground might be better on most circumstances, I'm confident on PIMETA's implementation and also on what Dr. Merier Corda has to say. In my above post I said that ground-wire on some of my cans are actually having a higher resistance (about 1 Ohm) than the hot-wires (right/left channels); this might translate into possible crosstalk issue on >10KHz frequencies or even EMI/RFI/radio-waves getting injected into the headphones, especially when speaking about high impedance cans and more than 3 meters long cables. I really think that going balanced or active-ground driving might help under this scenario, in compare with the single-ended.


----------



## Rroff (Dec 4, 2018)

carlmart said:


> The Pimeta does implement a virtual ground with an opamp, the TLE2426, only more compactly packed. For headphone drivers it's a simpler powering system, certainly better than using two batteries in portables, using the mid junction as ground. Those batteries may discharge differently and cause power unbalances. The other way is to use a DC-DC supply to generate the +/- voltages. Using the TLE is a simpler way to do that that may work on such circumstances.
> 
> 
> 
> ...



What I'm talking about isn't so much the virtual ground part of the equation itself though - but the full 3-4 channel active topologies - you can also drive these setups using a charge pump or other DC-DC POL with dual outputs or even from an AC transformer to get dual supplies it isn't the relevant part of what I'm talking about the circumstances where the AD8066 really seems to take off - for some reason where you have that setup with an AD8066 output one positive one negative on either side of the driver it really opens up another dimension of that opamp in audio use - especially any hint of veiling is almost if not completely lifted.


----------



## raoultrifan

I was referring to exactly the same scenario of 3-4 amplifiers and not to the rails splitting/virtual ground. I do hope all of us were referring to the same thing. If not, than Objective2's designer has a good article about rails split/virtual ground (eg.: making 2 rails out of 1 x 9V battery).


----------



## Ivan TT

Rroff said:


> full 3-4 channel active topologies


I recently implemented 4 channel active ground design in my Zishan DSD, tapping in 2.5mm 4 pole output and using OPA1622 configured as buffers providing separate buffered grounds to L and R channel outputs.
I notice better hanging of bass: higher resolution and each note's envelope clearly obvious; and improvement in soundstage due to fuller mids (as opposed to improvement in soundstage due to better/more resolved highs).
As OPA1622 has 5Ohm output impedance SOME BA IEMs don't play well though, when compared to SE output.
Overall buffered ground in 4 channel configuration was definitely an improvement, recommended.


----------



## raoultrifan

I'm sure 32 Ohms cans should play comfortable with the 5 Ohms output impedance.

Not sure this is the right DIY thread for this, but some pics with your design and work might be interesting, if you have the time for...of course.


----------



## carlmart

What options should I consider to swap the D50 output opamps? 

The factory ones are OPA1612, which many report as metallic sounding, some people here too. 

Any remedies you could find to tame the 1612s or only changing them?


----------



## raoultrifan

I wouldn't touch the OPA1612 opamps, these opamps are very good (proved by measurements).
Are we speaking about Topping D50, right? Have you seen D50's measurements on the Internet? This DAC is simply perfect, you just can't find a better one at this price level.


----------



## carlmart

There have been some complaints that the Topping D50 sound is a bit metallic, which gets a little better with a better power supply. 

The idea is to make the DAC sound better than its price level. For that you have to go DIY, and work basically on two areas: the analog output stage and the power supply.

There's no space inside to do anything, so the first thing to provide is a new top cover. Then you can place the regulators for the different power supplies outside the D50, as well as the new alternative analog output stages. 

Another option is to place the whole D50 box into another, larger, metallic box. Remove the top, leave it open, and run wires outside, where regulators and analog stages will be. 

Many people will find my proposal crazy or stupid, or follow the motto if it ain't broke, don't fix it. Well, I'm a diyer, and I have seen how things can be improved with not too much money and some effort. 

One important thing to consider with the D50 is that everything is small and fragile, particularly pcb tracks. That's why you must, IMHO, do everything outside and restrict soldering on the D50 to a minimum. 

About the D50 measurements, I don't think they tell the whole story, particularly about the sound qualities. I do think both measurements and listenings should be weighted for evaluation.


----------



## LaughMoreDaily

raoultrifan said:


> You could also try 2xAD797 with single-dual adapters, they’re the less noisiest from this group.


The 797 is a dual opamp, yes? What happens when you put two dual opamps on single dual adapter? A single meaning, one connection to the PCB right?


----------



## LaughMoreDaily

raoultrifan said:


> I wouldn't touch the OPA1612 opamps, these opamps are very good (proved by measurements).


That sounds a bit weird. You say you wouldn't touch a 1612 and then you say it's a very good opamp.


----------



## bunkbail (Dec 13, 2018)

carlmart said:


> There have been some complaints that the Topping D50 sound is a bit metallic, which gets a little better with a better power supply.
> 
> The idea is to make the DAC sound better than its price level. For that you have to go DIY, and work basically on two areas: the analog output stage and the power supply.
> 
> ...


I don't have the D50, but I have a $100 Khadas tone board and it sounds perfect to me, not metallic sounding at all. And it doesn't use a known off-the-shelf opamps, they are custom-made. Measurement wise, it is at least on par or better than the D50 and it speaks volume about the level of engineering put into it as it uses a single ES9038Q2M in stereo mode (D50 has them in dual mono config).


----------



## wolkegeist

I have a question,
Can I bridge 2 cmoy to create a balance setup, with each cmoy for L and R signal? and how can I bridge them if I could?


----------



## carlmart

LaughMoreDaily said:


> The 797 is a dual opamp, yes?



No, the AD797 is single. 



> What happens when you put two dual opamps on single dual adapter? A single meaning, one connection to the PCB right?



What happens is that you get a mess. Why would you connect four opamps to a dual adapter?

You are confusing the terms. A single adapter is for a single opamp. Usually a single SOIC chip to a single DIP adapter. 

What's common to is two single SOIC to a dual DIP adapter. And of course, dual SOIC to dual DIP adapter.


----------



## raoultrifan

carlmart said:


> [...]
> About the D50 measurements, I don't think they tell the whole story, particularly about the sound qualities. I do think both measurements and listenings should be weighted for evaluation.



goo.gl/y3KHYh, worth a read. As long as harmonics stay lower than -90dB, no hum gets audible, jitter is perfect, crosstalk very good...I don't see what needs to get improved. However, if you really intend to mod your D50, please find a way to measure it prior and after the modding, thank you!


----------



## raoultrifan

LaughMoreDaily said:


> That sounds a bit weird. You say you wouldn't touch a 1612 and then you say it's a very good opamp.


Perhaps I don't get the point here...sorry. If OPA1612 is already installed inside D50, then don't touch it, just leave it there.


----------



## raoultrifan

LaughMoreDaily said:


> The 797 is a dual opamp, yes? What happens when you put two dual opamps on single dual adapter? A single meaning, one connection to the PCB right?



I did that inside PLAY once, but you won't find any adapters for this operation, sorry...you need to do it yourself, though not quite recommended: https://www.head-fi.org/threads/new...mp-rollers-dream.860882/page-17#post-14034674.


----------



## carlmart (Dec 14, 2018)

raoultrifan said:


> goo.gl/y3KHYh, worth a read.



Did read that review. Good for a technical evaluation, sometimes wrongly called "objective". Very very poor for a product evaluation: not a single comment on how it sounds. Subjective tests seem not to be important for the tester.

If you like that kind of thing, OK. Not me, I need to have both. People need to know how a distortion, harmonic or whatever relates to what they are listening.

I know that same person evaluated a Schitt DAC some time ago, which had what he considered poor results, and raised a long discussion with Schitt users that thought otherwise.



> As long as harmonics stay lower than -90dB, no hum gets audible, jitter is perfect, crosstalk very good...I don't see what needs to get improved. However, if you really intend to mod your D50, please find a way to measure it prior and after the modding, thank you!



It seems you prefer "objective" results, which do not tell the whole thing. Listening quality is what needs to be improved, subjective results.

There won't be any measurements, and the mods will be external if possible, not internal.


----------



## Rroff

wolkegeist said:


> I have a question,
> Can I bridge 2 cmoy to create a balance setup, with each cmoy for L and R signal? and how can I bridge them if I could?



Yes - have a look at the PPA approach here https://www.head-fi.org/threads/pseudo-balanced-amplifier-pba.553236/ with a little modification it can also work fully balanced - I go with a little different approach myself - but this isn't really the thread to go into it in detail.


----------



## raoultrifan (Dec 14, 2018)

carlmart said:


> Did read that review. Good for a technical evaluation, sometimes wrongly called "objective". Very very poor for a product evaluation: not a single comment on how it sounds. Subjective tests seem not to be important for the tester.
> 
> If you like that kind of thing, OK. Not me, I need to have both. People need to know how a distortion, harmonic or whatever relates to what they are listening.



Take an original FLAC, purchased from a recording studio or online shop, import the song into an sound editing software (Adobe Audtion or some free applications will do). Then PLAY the same song on your equipment and record what you hear  or at least record DAC outputs with a good ADC and recording software. Later, you can compare the two audio representations in the editing software. You could also invert one of them, then mix them and only listen to the difference. Using a bad measuring DAC or headamp might cause some of such differences, most likely caused by unwanted harmonics and frequencies roll-off. By unwanted harmonics I mean sound distortions that recording studio didn't meant to be in our audio chain. 



carlmart said:


> There won't be any measurements, and the mods will be external if possible, not internal.


Too bad you don't want to do any measurements. This would be the only way to see any differences between the original and the final version, unless you have 2 identical units and you can actually A/B test them in real-time.

Good luck anyway, please take some pics with your mods.


----------



## carlmart

raoultrifan said:


> Too bad you don't want to do any measurements. This would be the only way to see any differences between the original and the final version, unless you have 2 identical unit and you can actually A/B test them in real-time.



Wrong, if by to see you also include hearing any differences. Maybe not many can do it, but I have been an audio professional for film & video for many years, so my memory audition was trained.

But as I won't be modifying anything on board, I may put a switch to select the output. 

To do measurements you need equipment, which I do not have.


----------



## raoultrifan

carlmart said:


> [...] To do measurements you need equipment, which I do not have.



Any decent soundcard will do for harmonics, but also for THD, IMD and SNR; also ARTA and RMAA are free.


----------



## raoultrifan

BURSON V5i on sale on Massdrop: https://www.massdrop.com/buy/burson-audio-v5i-opamps. Price is quite reasonable, for those interested and sound could improve your experience: https://www.head-fi.org/showcase/bu...d-opamp-v5i.21562/reviews?page=4#review-17405. V5i is probably on the bass-head side, but for some cans it could be a real improvement.


----------



## LaughMoreDaily

Is there anywhere online to buy the OPA2209 on a browndog adapter? Or maybe I have to buy the parts separately online and go to a local cell phone repair shop to solder them together?


----------



## LaughMoreDaily

raoultrifan said:


> BURSON V5i on sale on Massdrop: https://www.massdrop.com/buy/burson-audio-v5i-opamps. Price is quite reasonable, for those interested and sound could improve your experience: https://www.head-fi.org/showcase/bu...d-opamp-v5i.21562/reviews?page=4#review-17405. V5i is probably on the bass-head side, but for some cans it could be a real improvement.


Which opamps that are cheaper can beat this? I mean, I'm sure some of you like myself didn't buy this Massdrop because they're happy with another 'amp.


----------



## raoultrifan

Hard to say when cheaper and better are both in the same sentence.  V5i was completely designed from scratch only for audio purposes; from what I've tested (also confirmed by other headfiers) lowest octaves are a little bit overemphasized, so could be a good match with light cans, at least when used in Voltage-Gain.

Cheap and good opamps would be NE5532 or it's upgrade LM4652/LME49720. Of course, OPA1612 could be better, same applies to AD8599 etc.
Also, worth mentioning MUSES8820 and 8920, depending on what stage you need it.

of course, posting here the exact device you'd like to swap opamps for might help a bit more.


----------



## Zephead

After some time with the OPA2228 in my SMSL SAP ii Pro I've now switched to an AD823 and finding that about as good as I've found (tried OPA2604 (stock) OPA2107, OPA2227, LM4562, NE5532 and a couple of others that just didn't suit the application). I was still listening to the amp more than the music though so ended up buying an Arcam rhead and will be selling the SMSL, a Little Dot I+ and all my op amps.


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## CoiL (Dec 30, 2018)

Having burned-in AD8599ARZ for some time with my Aune T1, I`ve come to conclusion that it is tad "harsh" and loses in dynamic/naturality paired with Siemens E88CC goldpin + Fidelio X1 , compared to NE5532, which seems to be very well implemented in Aune T1.
I don`t want to say that AD8599ARZ is bad, no it isn`t - it is hyper detailed and clear, just tad "bright" sounding in that application. Maybe with some other tube combination it would be perfect but will leave that option for later testing as siemens e88cc goldpin tubes are best I have.
Next will try OPA1612 which is waiting after 8-DIP socket install in Aune T1.


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## bogginhead

I finally received my Muses01 and 02 for my E12 DIY and tried installing the 01 last night.  Once installed, the amp had no charge and I got the blinking blue light "status".  After taking the 01 out and putting the AD797 back in, the amp is back running normally.  I went back and tried again, this time making sure the 01 was seated well; I got the same outcome, lol.  Any idea on what might be causing this and how to fix it?


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## CoiL

You got ripped off? Where did You bought it from?


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## bagwell359

I've been trying out different op-amps in tuners made back in the 90's, and am convinced that there is value in optimizing them in equipment under consideration.  In this case the Cambridge CXC.  Wonder if anyone knows what it is? I've looked.  I'd rather just open it once to get the orig out, and get a socket in there to test 2-3 options.  Of course not so fast as I'd probably want to upgrade the caps too.

Thanks


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## bogginhead

CoiL said:


> You got ripped off? Where did You bought it from?



If you were meaning me, I'm pretty sure these Muses are legit.  I spent quite a bit of time researching sellers, and the op-amps themselves.  I also paid what seams to be the current going rate of a genuine Muses ($35 a piece).  These very much have the extremely soft legs on them, too


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## CoiL (Jan 8, 2019)

CoiL said:


> Just finished installing AD8599ARZ into Aune T1 headamp board...
> 
> 
> 
> ...


Got my OPA1612 installed instead AD8599ARZ and OOTB I seem to prefer OPA1612 straight away. It is back to point as NE5532 where I can hear Siemens E88CC goldpin tube signature - open,airy, holographic without being "thrown in face with detail" like AD8599ARZ.
Will leave it playing for a week and then compare to NE5532.
Also, installed roll-able socket.


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## SpudHarris

Is the LME49724MR not a plug and play single OpAmp?

I have soldered them up as such and smoked (literally) 4 off them.

http://www.ti.com/lit/ds/symlink/lme49724.pdf

Any advice appreciated...


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## ScottFW

SpudHarris said:


> Is the LME49724MR not a plug and play single OpAmp?



LME49724 is not a single opamp as typically used in audio devices. Never used one myself but it's definitely not going to be plug-and-play according to the linked datasheet.
A standard single opamp like a NE5534 has the +V supply on pin 7 and the -V supply on pin 4.
The LME49724MR is a differential opamp with a different pinout. Datasheet shows +V supply on pin 3 and the -V supply on pin 6.
I'm guessing the smoke is let out because you are connecting the 49724 pin 4 (Vout+) straight to the circuit's negative supply, basically creating a dead short.
That opamp is also incompatible with the dual opamp pinout that you're mostly likely to run into, e.g. NE5532.


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## SpudHarris

Thanks ScottFW, much appreciated. Do you think there would be a work around or adapter that would enable its use in a normal application?


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## CoiL (Jan 12, 2019)

I have a question about Aune T1 DAC differential opamp (stock is OPA2134) - how do I know if I need 2-channel FET-input opamp or can use AD8599ARZ in that place for example?
Wish to try out changing OPA2134 to V5i-D or AD8599ARZ but have no idea what requirements that circuit needs to test out different opamps in that place.

Also, any other recommendations for headphone amp board opamps? 
I`ve tried so far OPA1612, AD8599ARZ and NE5532AP.


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## Ivan TT

CoiL said:


> how do I know if I need 2-channel FET-input opamp


Usually FET input opamps used a term volume control potentiometer as they play well with varying input impedance.
Based on pcb photos it’s a bit hard to tell if that would be the case, I assume you are talking about dip8 opamp next to the gain switch?


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## CoiL (Jan 12, 2019)

Nope, that tiny SOIC-8 left from headphone amp board edge on main PCB:


Spoiler: OPA2134UA SOIC-8














https://eu.mouser.com/ProductDetail/Texas-Instruments/OPA2134UA?qs=7nS3%2bbEUL6vYkwg0jcwJMw==

Also, decided to try out ADA4084-ARZ and OPA2228PA for headphone board.
If those are not good, will probably stay with OPA1612 which is still "burning-in" but when I briefly listened to it after few days playtime, sounded good. Though, NE5532AD seemed to have tinybit more "air" between sounds that instruments/sounds decays/reverbs could "fill in".
Will do more proper listening end of next week.

I`m thinking that if AD8599ARZ would suit spec-wise into DAC differential opamp location to replace OPA2134, then it should give nice result combined with OPA1612 as HP amplifier.
No idea though.


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## raoultrifan

CoiL said:


> I have a question about Aune T1 DAC differential opamp (stock is OPA2134) - how do I know if I need 2-channel FET-input opamp or can use AD8599ARZ in that place for example?
> Wish to try out changing OPA2134 to V5i-D or AD8599ARZ but have no idea what requirements that circuit needs to test out different opamps in that place.
> 
> Also, any other recommendations for headphone amp board opamps?
> I`ve tried so far OPA1612, AD8599ARZ and NE5532AP.



You should be fine with AD8599 or OPA1612 or even MUSES8920 in I/V stage. LME49720 should do as well, but also 2xAD797 if you can DIY a bit. Settle down to those opamps that are delivering the least background noise and least temperature on their shell.

For headphones amp keep the opamps that are delivering lowest background noise, lowest temp on their shell and lowest noise/hiss when moving the volume control/switching gain/powering ON-OFF (thumb noise).

P.S.: It's more important to ensure stability and compatibility between opamps and PCB and surrounding components, this is why I care less for the output sound than background noise. temperature of opamps and no noise-sound when switching power ON/OFF, gain adjust or while volume knob rotation.


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## CoiL (Jan 13, 2019)

raoultrifan said:


> You should be fine with AD8599 or OPA1612 or even MUSES8920 in I/V stage. LME49720 should do as well.


By I/V stage You meant that I`m ok to swap OPA2134 with AD8599ARZ ? I`m thinking it will be best by specs for DAC differential opamp and provide OPA1612 with cleaner, more detailed signal and pair up nicely with OPA1612 sound signature.
Just to be sure, are ADA4084-2ARZ and OPA2228PA also compatible to try out in that spot? Don`t wish to buy any more opamps since upgrade isn`t very noticeable so far. I guess upgraded caps are doing their work very well.



raoultrifan said:


> For headphones amp keep the opamps that are delivering lowest background noise, lowest temp on their shell and lowest noise/hiss when moving the volume control/switching gain/powering ON-OFF (thumb noise).


So far havent noticed any problems with OPA1612 and AD8599ARZ in that place. No click with gain switch, no noise/hiss with vol control, no power-on pops (audio chain won`t switch on before tube has warmed up, so it isn`t audible anyway).


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## Rroff (Jan 13, 2019)

OPA2228 isn't a drop in replacement if you don't know the circuit - it is optimised for gains of 5 and above and fussy about capacitors around it and load capacitance - pay attention to the section in the datasheet "Using the OPAx228 in Low Gains" as it is also helpful for using it in wider application. Very good opamp when supported properly but I've seen some fairly experienced people dismissive of it with their subjective evaluation of how it "sounds" showing it plainly wasn't stable in their use.

One of my favourites for "easy listening" as it is quite forgiving on the quality i.e. if you are feeding it with a so-so quality MP3 without ever sounding like it is lacking in detail with a nice smooth low fatiguing presentation.


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## CoiL

Thanks for info. Won`t try OPA2228PA as DAC differential opamp then. AD8599ARZ first and then ADA4084-2ARZ, maybe OPA1612 too if I find other chip better in HP section.


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## carlmart

Have you guys played around with RIAA preamps? What chips worked best and on what specific circuits?


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## raoultrifan

Not personally, but any audio opamp should do; I would start with the opamps presented here: http://sound.whsites.net/project06.htm.

RIAA curve is tested by preamp’s manufacturer and swapping opamps might change that (we don’t want that); as there are not test vinyls to do RMAA tests, you might want to share here your preamp’s design/schematic and find together a better replacement (if any).

However, the only improvement you might get would be an opamp with similar specs but lower internal noise. Also, given the high gain used in RIAA preamps a scope to test for possible oscillations mighf be needed (or at least check for opamp overheating).


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## CoiL (Jan 22, 2019)

CoiL said:


> By I/V stage You meant that I`m ok to swap OPA2134 with AD8599ARZ ? I`m thinking it will be best by specs for DAC differential opamp and provide OPA1612 with cleaner, more detailed signal and pair up nicely with OPA1612 sound signature.
> Just to be sure, are ADA4084-2ARZ and OPA2228PA also compatible to try out in that spot? Don`t wish to buy any more opamps since upgrade isn`t very noticeable so far. I guess upgraded caps are doing their work very well.
> 
> 
> So far havent noticed any problems with OPA1612 and AD8599ARZ in that place. No click with gain switch, no noise/hiss with vol control, no power-on pops (audio chain won`t switch on before tube has warmed up, so it isn`t audible anyway).





Rroff said:


> OPA2228 isn't a drop in replacement if you don't know the circuit - it is optimised for gains of 5 and above and fussy about capacitors around it and load capacitance - pay attention to the section in the datasheet "Using the OPAx228 in Low Gains" as it is also helpful for using it in wider application. Very good opamp when supported properly but I've seen some fairly experienced people dismissive of it with their subjective evaluation of how it "sounds" showing it plainly wasn't stable in their use.
> 
> One of my favourites for "easy listening" as it is quite forgiving on the quality i.e. if you are feeding it with a so-so quality MP3 without ever sounding like it is lacking in detail with a nice smooth low fatiguing presentation.



Woah! Didn`t expect this out of OPA2228 used as HO opamp with Aune T1!
Very organic, natural and open sounding! And seems to deliver quite good amount of details. 
Soundstage seems VERY open and airy but not sounding distant/laid-back with Siemens E88CC tube.
Bass & percussion hits hard, tight and clean. Vocals/mids seem very natural. Guitars full and weighty.
Seems 45mA per channel output does its work better than stock 38mA.
I`m suspecting this will be best for my ears out of NE5532P, AD8599ARZ, OPA1612AID but will let it "burn-in" for week and do more proper comparing along with ADA4084-2ARZ which I will receive in few days.
Initial impressions - OPA2228PA put a BIG smile on my face and head bangin! ;P


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## FritzS (Jan 24, 2019)

CoiL said:


> Woah! Didn`t expect this out of OPA2228 used as HO opamp with Aune T1!
> Very organic, natural and open sounding! And seems to deliver quite good amount of details.
> Soundstage seems VERY open and airy but not sounding distant/laid-back with Siemens E88CC tube.
> Bass & percussion hits hard, tight and clean. Vocals/mids seem very natural. Guitars full and weighty.
> ...



If OPA2227 are better for low gain amps? Needs OPA2228 a compensation in low gain amps?
What are the difference between OPA2227/OPA2228 and the FET OPA LT1057 (and ‘family‘)?
I want to upgrade an Solo headphone amp. Solo use original AD823.


----------



## CoiL

FritzS said:


> If OPA2227 are better for low gain amps? Needs OPA2228 a compensation in low gain amps?
> What are the difference between OPA2227/OPA2228 and the FET OPA LT1057 (and ‘family‘)?
> I want to upgrade an Solo headphone amp. Solo use original AD823.


For those questions, someone with more knowledge here should answer You. 
I`m just doing simple opamp swap in pretty simple headphone amp board (basically c-moy type with gain switches). 
In different applications results may vary. But with Aune T1 - OPA2228 sounds crazy good and seems to bring Siemens E88CC goldpin tube to its maximum potential.


----------



## Rroff

FritzS said:


> If OPA2227 are better for low gain amps? Needs OPA2228 a compensation in low gain amps?
> What are the difference between OPA2227/OPA2228 and the FET OPA LT1057 (and ‘family‘)?
> I want to upgrade an Solo headphone amp. Solo use original AD823.



You'd have to check really, with an oscilloscope, on a case by case basis whether the OPA2228 was stable in a low gain amp - there is a section in the datasheet about it. My subjective impression is that the OPA2227 is a bit different to the OPA2228 though they both have that so called "burr-brown" sound the 2228 is just a bit more organic - the OPA2227 IMO is a great replacement for the OPA2132/2134 which personally I find somehow sound uninvolved in the music even though they are generally pretty close to transparent. If you want an alternative to the OPA2228 that is stable in low gain amps then there is the OPA2209 but AFAIK it isn't available in DIP8 format so you'd have to mount it to an adaptor - though it doesn't have quite the bass of the 2228.

I'm not personally very familiar with the LT1xxx family.


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## FritzS (Jan 30, 2019)

Now I searched in my old archive and found an old Austrian Praktiker DIY project from 1983 (!) which use some 5534 OPAs. 5534 is one of the longest standing OPAs too.
The output stage from 5534 could be easy drive to decrease Crossover Distortion with an 68 Ohm resistor between pin 6 and pin 5, in my opinion this knowledge may have been lost. Which I don't know if this will increase the idle current in the output transistors. It would be more effective to simply measure that. At the moment I lack the tools to do it.






> .... der Widerstand R4 hat einbe besondere Aufgabe: bei kleinen Signalpegeln wird die Übernahmeregion des Ausgangsverstärkers in U1 (5534) überbrückt - die Verzerrungen bei kleinen Signalpegeln werden dadurch reduziert.





> ..... the resistor R4 has a special task: at low signal levels the crossover region of the output amplifier in U1 (5534) is bridged - this reduces the distortions at low signal levels.


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## carlmart

The big problem with 5534s is that you always have an output DC offset, so you need to put a blocking capacitor. 

Only by using a DC servo do you get to eliminate the cap.


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## FritzS (Jan 30, 2019)

carlmart said:


> The big problem with 5534s is that you always have an output DC offset, so you need to put a blocking capacitor.
> 
> Only by using a DC servo do you get to eliminate the cap.



Does this offset change strongly or can it be permanently minimized with offset correction?

In this old DIY project, there are some caps in signal path for blocking DC.






Some manufacturers still use 5534/5532 in the analog filter stage of CD/SACD players today,
detto 5534/5532 is still used in professional audio equipment.


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## carlmart

Almost all manufacturers put capacitors inter stages or at the output, so you don't have to consider their uses as the best for quality audio. 

They will say that nobody can listen differences with cap or no cap. It's imagination when somebody say they do. They belong to the "objective" school, where if it can't be measured it doesn't exist. So they are not to be trusted.  

High quality single chips, like the 5534 or LT1028, have null pins, where you can zero the offset. But on chips like the 5534 it drifts from zero all the time, so you can't trust the null: cap or DC Servo. 

The LT1028 or AD797 are more drift-free, and you can trust them to remain close to zero offset. You just need to check the datasheet of the IC you are planning to use and see what's their offset without any null. Most modern chips can be used without any caps..

The 5534 is still a very good sounding chip, much better than the 5532. It does always deserve a listen, with cap or servo. The other problem is that the cap has to be large, usually an electrolytic type.

In any case, I always follow Ben Duncan's advice: do not use any interstage caps, and put just one high quality film cap at the last stage, before the power amp or headphone amo.


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## FritzS (Jan 30, 2019)

carlmart said:


> In any case, I always follow Ben Duncan's advice: do not use any interstage caps, and put just one high quality film cap at the last stage, before the power amp or headphone amo.



Pity that the best electrolytic capacitors in my opinion, the nonpolarized Black Gate electrolytic capacitors, are no longer produced!

I use BlackGate NX 1000 uF 25V at the output of my headphone amplifier too. Till today I don't found similar nonpolarized electrolytic capacitors!


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## carlmart

There was a research article, some years ago, that the best choice, both measured and on listening tests, was two bipolars in series, no bias in between. 

You can find the article in Linear Audio's site.


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## raoultrifan

carlmart said:


> [...]
> They will say that nobody can listen differences with cap or no cap. It's imagination when somebody say they do. They belong to the "objective" school, where if it can't be measured it doesn't exist. So they are not to be trusted.[...]



I this a contradiction or am I misunderstanding?
I think subjective people assumes that a cap might be better than another cap, of course...without providing any evidence or measurement. Usually, if on scope measurements across audio-bandwidth there is no phase-shift nor phase-delay then that cap should be good for use inside audio equipment. It actually quite simple to measure this...just need to use a scope and see the phase; of course, RMAA or ARTA will help too. 

Also, the plain-old "best cap is no cap" or "wire with gain opamp" etc. are usually to be on the safe side, so yes...it's more technically advanced to use DC-servo or DC protection instead of a cap to block the DC, but it's always cheaper and good enough for audio equipments to use a decent MKP cap.


----------



## raoultrifan

FritzS said:


> [...]
> 
> I use BlackGate NX 1000 uF 25V at the output of my headphone amplifier too. Till today I don't found similar nonpolarized electrolytic capacitors!



It's all about proper calculation of the output low-pass filter, nothing else: http://sim.okawa-denshi.jp/en/CRlowkeisan.htm. And if you have a scope around (preferable a frequency generator too, if not already built into the scope), you can actually check for any phase shift or phase delay for any audible frequency you might want (usually 20Hz, 50Hz, 100Hz, 1KHz, 5KHz, 10KHz, 15KHz, 20KHz).

For the input caps here's an example of what a cap in signal path can do:

*Original HPA-3B with 2.2uF input caps*
https://cdn.head-fi.org/a/10082789.png

vs.

*Audio signal applied after the input caps (or short-circuit input caps)*
https://cdn.head-fi.org/a/10082797.png

With square waves it might look nasty, but in real life it's a roll-off at 20Hz of about 0.3dB, so nothing to worry about. I was unable to actually feel any difference on my headphones when doing a short-circuit on the audio caps. Maybe if the difference would be 0.5dB or higher, then it would cause an audible concern, but for less than 0.3dB that I was able to measure, I really care not.

TL;DR: From https://www.v-cap.com/coupling-capacitor-calculator.php we can calculate the output capacitor values for our audio equipment, we should simply choose 2Hz for the frequency and 10...50 KOhms for the input impedance of the connected equipment, to be on the safe side (for DAC's or preamps only, not for speaker amps!).
For power amps instead, we should understand why some of them are not perfectly flat, especially on the low-end (-1dB at 20Hz), because if we calculate the output filter capacitor for a 3-dB roll-off @ 2Hz and need to connect 4 Ohms speakers that are actually 3 Ohms in real measurements, then we might need a 26525uF capacitor on outputs (quite expensive and bulky design)!
So again, based on the design, sometimes indeed best cap is no cap, unless we're happy with a -3dB roll-off @8Hz instead of 2Hz and we'll never connect 4 Ohms speakers, only 8 Ohms, that actually measures around 6 Ohms on the bass department (I'm speaking about impedance @ 20-30Hz), so a 4700 uF will do very well here. Of course, sometimes a cheap cap will simply work very well, it's all within the design and calculations.


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## FritzS

It's only for headphone amps - AKG K812/872 have 36 Ohm, Denon AH-D7000 have 25 Ohm.


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## raoultrifan

If it's for a cap connected at the output stage, just before the headphones, then for 25 Ohms cans a cap's value of 3182,10 uF is required (-3dB roll off @2Hz).
Of course, thinking to 8 Ohms IEMs, then a 4700 uF will be good enough (16...25V should do, depending on how powerful is the amplifier). Of course, a Nichicon/Elna/Panasonic/etc. for Audio-use would be just fine, even the cheapest as long as it's an original brand.

P.S.: Are you referring to a specific amp or schematic?


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## carlmart

Don't you think it's insane to connect your phone through a large electrolytic cap?


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## raoultrifan (Jan 30, 2019)

https://en.wikipedia.org/wiki/Capacitive_coupling#Use_in_analog_circuits
https://electronics.stackexchange.com/questions/18301/how-does-a-capacitor-block-dc
https://www.quora.com/Which-components-block-DC-signals-and-allow-AC-signals-to-pass - first answer should do.
etc.






The *Cout *from the OPA1177 datasheet is connected on output to protect headphones for any possible DC voltage. There's also the formula on the right to calculate it's value. Please notice the recommend value for the input cap *C2* as well: 10uF for a 100KOhms input impedance, quite a generous value and somehow expensive given the MKP caps price (usually 4.7uF does the job well).

Basically, we need to ensure headphones/speakers protection from damage in case of a DC voltage appears on outputs, usually when something breaks inside, but also sometimes from unwanted transients from power supply when ON and OFF. If the second part could get resolved with relays and appropriate delay after powering ON the device, when the output stage breaks (or some opamp from the internal schematic gets broken) the DC voltage from the power rails is usually injected directly into the speakers/headphones and these breaks almost instantly, because they simply don't like DC...they only work well on AC (sinewaves).

A DC higher than 50mV might be considered pretty high for most consumer headphones, this why Objective2 designer accepted a max. of 3mV per channel (just got this example in mind because is a very well documented design). For 600 Ohms cans a 25-30 mV could be OKish.

The best way to combat output DC is by implementing DC-servo on outputs, like here: http://www.ti.com/lit/ug/snaa052a/snaa052a.pdf. Yes, the basic schematic from the Texas Insturments LME49600/LME49720 Stereo Headphone Amplifier datasheet. Half of the gain-stage opamps are used to combat any possible DC-voltage.

L.E.: Not all the amplifiers need DC blocking components, a simple protection that disconnects headphones-out should do, like the *uPC1237 *chip does, which is already integrated into headamps from Burson, Matrix a.s.o.


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## FritzS

I know all about, but this is a given amp. 
I know about a better protection for headphone amps like this:
https://www.amb.org/audio/epsilon12/
or the uploaded file:


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## FritzS (Jan 31, 2019)

My given amp, but I don't want to modify them anymore. This was a DIY project in RockGrotto Forum and here in head-fi.
https://www.head-fi.org/threads/new-wna-mkll-head-amp-kit.99596/
C1 - only a wire bridge
R11 - 15 Ohm
C4 - 1000µF 25V BlackGate unipolar
OPA LM6171, but now AD797



Railsplitter:
OPA LM6171


----------



## FritzS

Some given headphone amps don't use DC protection too, but have very low offset voltage on output.
For example from Jan Meier or the Funk Modules.


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## raoultrifan (Jan 31, 2019)

AFAIK all Meier Corda amps are DC-coupled, but don't have access to full schematic to see if they got DC-servo inside or not. Sometimes, taking very good care to components installed might not need other than including DC-voltage measurements in the Q&A process and that's it. As long as there are no opamps to swap (all are soldered) and you're 100% sure none of the two rails will never fail, then everything's fine. This is why I said in one of my previous post that designer will choose what's best schematic and best components for the amplifier. 

The Funk Modules are DC-coupled and are using DC-Servo, exactly like the schematic shown above with LME49600: http://funk-tonstudiotechnik.de/SYMM-VERST.htm#Headmaster, so no need for any headphones protection.

Given the mods you've done inside the RockGrotto DYI headamp, my personal thoughts:
- by increasing C4 from 220uF to 1000uF you are ensuring a better compatibility with low-impedance cans, in regard with bass roll-off, so a totally recommend mod for this project
- I'm not sure why you increased the R11 from 10 to 15 Ohms? I would personally try to install better heatsinks on the output transistors, perhaps replace R7, R8, R9, R10 with 5 Ohms resistors and simple short circuit the R11 to get a better dumping factor when using low-impedance cans, otherwise I see no reason for upgrading the C4 caps, right? Right now you have 25 Ohms connected at the output of the amplifier, from what I see in the schematic. Of course, double check for overheating is required; if so, then replace output stage with BD239/BD240 transistors and increase heatsinks a bit more.
- This amp is not AC-coupled, because it has a cap in front of the opamp, so in case you connect a DAC that has 5mV of DC-output your amplifier will not get the DC over-amplified again. Also, the outer cap protects the headphones of any DC-voltage coming from the output stage.


----------



## raoultrifan

FritzS said:


> Some given headphone amps don't use DC protection too, but have very low offset voltage on output.
> For example from Jan Meier or the Funk Modules.



Well, usually protections are only to prevent headphones destruction in case of an "internal accident", like when one of the power rails fails, or when you swap opamps and insert it vice-versa into the DIP8 socket, or if a power transistor on the one in front of it (driver) will fail from overheating. Protection only ensures that output jack will get disconnected from the amplifier's board. Under normal conditions we might not need protection at all.


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## FritzS (Jan 31, 2019)

Last year Jan Meier lent me the CORDA CLASSIC-ff for a test and presentation at the Head-Fi Meeting in Vienna. Its offset voltage was between 0 and +- 2mV, I measured this several times
Jan Meier use AD797 and paralleled BUF634. From this experience I also used AD797 in the WNA MKII, although Jan Meier's CORDA CLASSIC-ff offered a bit better, finer resolution - comparing with my WNA MKII.
BUF634 (and LME49600 and similar too) is the integrated version of Walt Jung's design. BUF634 is the integrated version of Walt Jung's design. Unfortunately the pages of waltjung.com and waltjung.org are now closed. Fortunately I saved the document '_WTnT_Op_Amp_Audio_2.pdf_' (and some others from Walt Jung) on my PC.

As for Funk, I mean his module LPA-2S or LPA-2S+. He uses two OPAs but you can't see whether it's single or dual. Does he now use DC servo as suggested by National?
There are coupling capacitors in his SIA-5 symmetry modules.

http://funk-tonstudiotechnik.de/LPA-2S-englisch-300.pdf
http://funk-tonstudiotechnik.de/SIA-5.V3.pdf
http://www.ti.com/lit/ug/snaa052a/snaa052a.pdf


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## carlmart

Which is the Walt Jung design you talk about? The one with a regular opamp on first stage and a BUF634 as second?

There's a RIAA design in the LT1115 datasheet, that can be used as headphone amp, eliminating the RIAA filter. 

There's a design by Pavel Macura, with OPA627 in first stage and BUF634 in second, that can be used for headphones.

http://pmacura.cz/buffer_en.html

You have to adjust the gain and put an output series resistor, value the same as the headphone impedance. .

It should work quite well. I'm not sure why you would need two BUFs in parallel.


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## raoultrifan

@carlmart, please follow the LME49600/LME49720 schematic. You need at most 10 Ohms output resistor or check Ventus amp schematic from Twistedpearaudio and how they improved the dumping factor with a simple inductor and resistor: http://www.twistedpearaudio.com/docs/linestages/ventus_ez_schematic.pdf.

Damping factor and DC-servo from above should be taken into consideration if performance and specs are important for us.

I think Meier Corda paralleled BUF634 to increase the output current and at the same time to decrease THD by "oversizing".


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## FritzS

carlmart said:


> Which is the Walt Jung design you talk about? The one with a regular opamp on first stage and a BUF634 as second?
> 
> There's a RIAA design in the LT1115 datasheet, that can be used as headphone amp, eliminating the RIAA filter.
> 
> ...



I talk about the schema of BUF634 (and other buffers too).


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## FritzS (Feb 1, 2019)

@carlmart @raoultrifan
All this looks like the diyaudio “The Wire SE-SE“ project too.
https://www.diyaudio.com/forums/ven...s-projects-available-bal-bal-se-se-lpuhp.html
https://www.diyaudio.com/forums/hea...tra-performance-headphone-amplifier-pcbs.html
https://www.diyaudio.com/wiki/The_Wire_-_All_Boards_and_Kits_Explained_Here
https://drive.google.com/file/d/0B3MLwB9mdXl2bjdXempqRG1lMFE/view


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## FritzS

raoultrifan said:


> I think Meier Corda paralleled BUF634 to increase the output current and at the same time to decrease THD by "oversizing".



Jan Meier runs the BUF634 in BW mode with increase idle current, so they runs (over long stretches) in Class A for the most headphones. Jan tells me, he let run AD797 output-stage in Class A too.


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## FritzS

Praktiker (an Austrian DIY magazine) used this buffer design in a DIY project as early as 1983.
 

Literature reference from this project, interested 'who is who in audio design'


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## raoultrifan

FritzS said:


> I talk about the schema of BUF634 (and other buffers too).


 The LEDs are most likely used to bias the output transistor into Class A/B, the idle current actually. Perfect match of LEDs and transistors will decrease the crossover distortions.


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## FritzS

The core of the buffer schema are only Q1 ... Q4, all other components are current sources, current limitation, temperature operating point stabilization, crossover distortion prevention, etc.
PS: Have you contact to MEZE Audio? They are from Romania too.


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## raoultrifan

Hi @FritzS, I never contacted Meze before...no, not sure why to do that, they got so many reviews here on Head-Fi and so many new headphones coming up, that I feel like I might bug them with my emails.


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## carlmart

FritzS said:


> I talk about the schema of BUF634 (and other buffers too).



That buffer was suggested by WJ for a CD mod he did on a Philips player, so the output current capability is limited. It may work will less current hungry heads. You should change the output transistors to mi-power types.

It is not offset free either, so you still need an output cap.


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## FritzS (Feb 1, 2019)

I own an old Philips CD 650 too, in both output lines (cinch and headphone) are electrolytic caps. For cinch I changed them to Nichicon KZ.
Philips TDA 1541 DAC produce an DC offset.

The Marantz CD/SACD Player SA7001 KI use electrolytic caps in the output lines (cinch) too. Two 220µF 16V (ROS-*16V221MH5* ELNA) in series (polarized backwards).

On other side (as far as I know) RME use in it's studio ADI-2 .... a DC protection. The DACs and analog amplifiers are DC coupled, but if the digital section has an error and produce only 1111... or 0000... bits, full DC are on output. This can happen with their complex digital signal processing. And software is not always error-free.
http://www.rme-audio.de/en/products/adi_2-dac.php


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## FritzS

Sorry that we now deviate from the pure OPA topic, I hope that nevertheless also others are interested in it.
Sorry about my not so good English, I use this helpers:
https://www.deepl.com/
https://www.dict.cc/


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## carlmart

FritzS said:


> I own an old Philips CD 650 too, in both output lines (cinch and headphone) are electrolytic caps. For cinch I changed them to Nichicon KZ.
> Philips TDA 1541 DAC produce an DC offset.



By using different output ICs you could eliminate the capacitors. There were several projects in The Audio Amateur doing that. But a simple change t two series bipolar caps could improve things easier. 



> The Marantz CD/SACD Player SA7001 KI use electrolytic caps in the output lines (cinch) too. Two 220µF 16V (ROS-*16V221MH5* ELNA) in series (polarized backwards).



You could put a multimeter before the Marantz cap to see if there's a DC offset. It could be eliminated with a DC servo, but you would need to know some electronics. Once again, replacing the capacitors for series bipolars is the easy way out.


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## raoultrifan

The caps from input and output of an amplifier are not to remove the few mV of DC-voltage from outputs (that does't means a lot anyway) it's more to protect the headphones (or speakers) in case of an internal defect. Imagine what happens if you connect a DAC with 50mV of DC-voltage to an amplifier with a gain of 10X; that would be at least 500 mV of output DC, right?

Input cap if to remove any possible DC from the inputs, output cap is to protect the output source for any possible DC from the amplifier itself (usually if something goes wrong, like a power regulator gets defective).
Most of the new amplifier designs are not using caps anymore, just output protection circuits (these simply disconnects the output source) or DC-servo.


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## FritzS (Feb 1, 2019)

In my opinion capacitors are necessary after a DAC, less because of the low offset, but they prevent massive DC voltage at the output of the analog filter from being connected to the DAC in case of an error in the calculation. Today DAC are computers with DSP and firmware (which can be faulty).
RME does this by using DC detection and a relay.
In the studio area you can also find transformers whose side effect is the protection against DC fault voltage.
The manufacturer of a DAC cannot rely on the manufacturer of the following device.

(Translated with www.DeepL.com/Translator)


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## carlmart

Yes, having a relay protection from DC or spikes on a headphone amplifier is a good thing indeed. 

I'm not sure if speaker's protection can be used on such amps. probably yes. 

Such a protection is easily available in eBay nowadays, cheap and very compact. It isolates the load in milliseconds, before any damage occurs. 

The price you pay is the relay contact, which has to be a good quality one and isolated. 

This is much better than a capacitor in series.


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## Con Par (Feb 9, 2019)

Guys i just got the Topping nx3s. And im looking forward to change the stock internal op amp which is the* LME49720*. is there any good replacement for it? i have read in another thread that the *LT1364 *change the sound by a lot.
Whats your opinion?
Thank you and sorry for my english.


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## raoultrifan

Given the higher slew rate and speed I don't think this is a recommended swap. However, feel free to watch https://www.head-fi.org/threads/topping-nx3s.891339/page-2#post-14688999, although the LME49720 should have no flaws inside the NX3s and might no need to get swapped at all.


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## carlmart

Even if the gain bandwidth and slew-rate are considerably better on the LT1364, I think I agree with raoultrifan. 

If the NX3 opamp type is PDIP 8 you can install a socket and swap different opamps to find one to your liking. But if it's an SMD type think twice. 

It might be a better option to assemble an external output, with its own power supply, and make your tests there. 

I own a D50 and it's what I plan to do, particularly because of the lower voltage (+8/-8v) of the output's power supply.


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## raoultrifan

But D50 is already measuring about perfect? Why fell like changing anything inside this DAC?
Why increasing the voltage on the opamps will change anything in D50?


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## wolkegeist

I’ve just got a modified DIY O2 amp, the stock op amps are dual OPA132 for input stage and dual OPA2111KP for the output stage. It sounds a little bit tube-ish. What op amp should I change for a clear and balanced sound?


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## Rroff

The input - should be a single dual opamp - is the gain stage and generally has the most impact on sound - the output stage should be 2x dual opamps. If you literally just want clear and balanced sound then LM4562 for the input and 2x RC4580 for the output would give that but musically probably a bit cold.

The OPA132 probably has the most impact in the configuration above though the combination probably comes from both as the OPA2111KP IIRC is often described as a bit tubey.


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## raoultrifan

These are not originals at all, these have been added after the modification for sure. O2 has, in the original design, the very low-noise NJM2068 (also used now in the extremely low-noise JDS Atom) was used in the input/gain stage and the buffers were NJM4556 paralleled.

I strongly suggest you to revert to the original opamps, at least on the output buffers that are probably oscillating and overheating, not mentioning that OPA211KP are able to deliver +/-10mA vs. the max. 150mA delivered by the NJM4556.

However, if you'll never use planars or hard to drive cans with your O2, you might install MUSES8920 if you really don't like the original NJM4556 opamps, although...besides a lower output DC of 1mV vs. 3mV I wasn't able to find other highlights.


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## Rroff (Feb 10, 2019)

Yeah was wondering about that with the OPA2111 only able to supply 10ma - was hoping it was actually in the gain stage as terrible choice for O2 buffers.

The NJM4556 are pretty decent if you have headphones that need a lot of current and work well in that configuration but I'm not as convinced by them for overall use especially with high impedance, low current headphones - hence I prefer the RC4580 as a straight replacement if sticking with the spirit of the original amp.

Personally my O2 variant at the moment is running an OPA1692 gain stage and OPA2209 buffers but that isn't very DIY friendly.

OP275 is also quite good with this setup.


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## raoultrifan

Rroff said:


> The input - should be a single dual opamp - is the gain stage and generally has the most impact on sound - the output stage should be 2x dual opamps. If you literally just want clear and balanced sound then LM4562 for the input and 2x RC4580 for the output would give that but musically probably a bit cold.
> [...]



Interesting opamp: http://www.ti.com/lit/ds/symlink/rc4580.pdf, thanks for sharing @Rroff. I don't remember of anyone testing this, and I think I had the entire diyaudio forum on the O2 thread, but definitely I missed one page for sure.  Happen to know if someone tested this under a scope? 

I'll purchase a couple of these to test them, thanks again.


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## wolkegeist (Feb 10, 2019)

The amp is highly modified by the guy I know, same schematic but different pcb design. Here’s the picture


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## Rroff

raoultrifan said:


> Interesting opamp: http://www.ti.com/lit/ds/symlink/rc4580.pdf, thanks for sharing @Rroff. I don't remember of anyone testing this, and I think I had the entire diyaudio forum on the O2 thread, but definitely I missed one page for sure.  Happen to know if someone tested this under a scope?
> 
> I'll purchase a couple of these to test them, thanks again.



As per the datasheet it is a drop in replacement for the NJM4580 and very similar to the NJM4556 but slightly less current capability but with a few tweaks by TI that in my opinion are an improvement on the original and it is designed around audio use - it is largely transparent possibly a touch raw sounding - it is no detail monster though sufficient but I've heard more revealing opamps.


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## raoultrifan

It has a lower output current, but I'll give it a try sometimes for sure.


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## Rroff

That is very modified from the original and the part numbers aren't clear enough on the opamps to know what the setup is so I'm not 100% sure on the best recommendations. The original design had a bank of 480uf caps in the power stage and 220uf feeding the opamps for a reason.


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## wolkegeist (Feb 10, 2019)

Rroff said:


> That is very modified from the original and the part numbers aren't clear enough on the opamps to know what the setup is so I'm not 100% sure on the best recommendations. The original design had a bank of 480uf caps in the power stage and 220uf feeding the opamps for a reason.


It’s for desk use only, so it’s wall wart powered, but I also have a different battery designed for it, by the guy I bought it from. I need two single op amps to replace the stock OPA132s tho. I think they are the reason for it to sound tubey. The stock buffer chips are JRC4556s but I replace them with OPA2111KP because I only have low impedance headphones like Grado SR80 and Etymotic ER4S. It’s very tubey with the 2111s and a little. V-shaped with the 4556 and the OPA132s. Coupling caps are Sprague 680uF 25V. The two op amps near the stereo jacks are dual OPA132, the op amps beside the big orange caps are two OPA2111KP


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## carlmart

raoultrifan said:


> But D50 is already measuring about perfect? Why fell like changing anything inside this DAC?



Who said "measuring perfect" equals or is the same as "sounding very good"? There's no perfect in subjective listening.

Only inexperienced or stubborn electronics engineers would say that. Pick someone like Walt Jung, Bob Cordell or Nelson Pass, who are electronics engineers that actually LISTEN to audio equipment, and you may get a much better opinion on what an opamp or a power supply can do to audio quality, 

You may want to change something when you think it may be improved, in this case anything on the audio quality. Or do you think an opamp doesn't have an audio signature?



> Why increasing the voltage on the opamps will change anything in D50?



Because specs will improve when you get closer to the maximum voltage an opamp was designed for.


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## raoultrifan (Feb 10, 2019)

An audio gear that is measuring very well in regard with several audio aspects is all it counts for me, because subjective listenings are mostly based on audio memory, which I don't trust, or incorrect A/B tests most of the times (it should be less than 1ms latency between swapping inputs sources which many times is not happening). However, I really appreciate a correct A/B test when I see it and I do trust these reviewers, especially if there are measurements to backup their assertions involved! Meanwhile, if I'll ever want to change the sound coming from my cans I'll just easily grab a DSP plugin, because I find a DSP plugin being cheaper than a new amp or DAC and with lot more flexibility in choosing the output sound.

The above engineers are picking up opamps inside their circuits based on the datasheet and audio measurements, not based on their ears, although odd harmonics do sound more fuller and better to our ears and some manufacturers are indeed "dialling-in" more odd harmonics by adjusting the bias-level or negative feedback, just to make the device to sound nicer, despite the increased THD. But indeed, listening is the most important part, so this is why less THD, less noise, less IMD, low mains hum, perfect freq. response and no phase delay means better audio performance...in all cases, no matter our subjective listening tests. After all, amplifiers are designed by engineers and not by musicians, even that both parties are involved in the final listening.

I'm not EE, nor a musician, I'm just an objective audiophile that realises that measurements are the first we need to read when picking up audio gear, and later the listening part, because different listening conditions will result in different opinions. A good reading about choosing audio gear could be found here: https://benchmarkmedia.com/blogs/application_notes/124929287-how-should-i-buy-an-audio-system. Worth mentioning that my "audiogram" shows that I can hear -85dBFS in a silent room with closed-back cans, I can distinguish a volume difference of less than 0.5dB and I do hear harmonics if worse than -70dB (THD of 0.03%) on speakers and only if worse than -60dB (a THD of only 0.1%) on headphones.

What I'm looking myself when listening for the first time to a new device would be a black background, lack of mains hum noise, no scratchy potentiometer, no audible distortions. Later, I look for a good match between the amp and my cans, because sometimes this is not happening due to different specs and needs (different designs, technical limitations etc.).

BTW, specs should be related to the measurements after all, and increasing the voltage inside D50 will not lower its harmonics below the existing -115dB (https://www.audiosciencereview.com/...ments/topping-d50-dac-measurements-png.19810/), and if it will, I'm not sure how will you be measuring this. Also, harmonics below -90dB are kinda impossible to hear.


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## carlmart (Feb 11, 2019)

I don't discard measurements, either from the datasheets or made for the tests. But I do think they are far from enough.

If eventually I had to choose between a review mostly based on measurements, like those from amirm from www.audiosciencereview.com, and another done by a serious reviewer, respected because of previous tests, like some people from Stereophile, I'd definitely go with the latter. You would apparently do the opposite, and that's a personal choice.

Those engineers I mentioned take datasheets as starting pointers, but they do extensive listening. The question is that there are many things that the human ear preceives that aren't or can't be quantified, for now at least.

Serious engineers that do reviews many times devise ways to measure what the ear perceives and the instrument do not show. Walt Jung is one of them.

You should read old reviews made in old Audio Electronics issues or in Linear Audio, and you will find many comments about how things sound, not just measure.

My thing is speakers, not headphones. But I did use Beyer DT48s in my film & TV audio engineer, going from locations to studios, recording all kind of things. You do develop that audio memory you don't seem to trust.

Let me tell you that you are completely wrong in not trusting audio memory, as you can educate your ear and your brain to serve you as the best tool there is, much superior to any instrument.

Recreating the original audio sound, as listened by your naked ear, was my job as location engineer. At the studios you had the best speakers and amplifiers money could buy, so the task was to reproduce that original sound as close as possible to what it was. A good reviewer does exactly that.

There's not such a thing as an "objective audiophile". By definition, and audiophile will always be subjective, never objective. If you do any measurements and know how to do them, that part would be the objective one. But correlating that to good or bad quality sound would be false. There was a time when electronics engineers said that if two amplifiers measured the same, they would sound the same. Some probably still do, but many are not that sure of that now.

Perhaps you should do the test of increasing power supply voltage to a good quality opamp, and listen to how it sounds different as you go higher in voltage. And if the measurements do not show any differences, then the measurements are faulty, not the listening. And for a trained ear, that anyone can achieve, there's not such a thing as "imagined" results. BTW, blind tests have proven nothing.


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## raoultrifan (Feb 11, 2019)

@carlmart I totally appreciate your comment and constructive critique, so thank you for your detailed answer!

I would love to see headfiers like this guy here  that is actually proving that he is right, but using his own recording studio. I'm pretty sure different harmonics and phase-shifts are changing the way we hear the sound, but as en engineer I think there is a good way to find what measurements we need to do to measure the sound.

BTW, for a better espresso we use a TDP-meter, which is far away from reality to tell you about the differences from a good and a perfect espresso, but will definitely tell you if you're done a bad espresso.  So doing measurements prior to listening it's like a phone-screen when dealing with a job-interview: you just need to ensure the guy really knows what's written on its CV, nothing else, the actual jobs interviews are done onsite anyway.


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## Spektykles (Mar 9, 2019)

Hi, I found an offer online for a pair of used AD797SQ (ceramic DIP version) for a very cheap if not suspicious price. Is there any fake ceramic chip out there? And quick dipping test with acetone still valid for today's fake chip or Chinese fakers learned something new?


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## LaughMoreDaily

Spektykles said:


> Hi, somebody offered me a pair of used AD797SQ (ceramic DIP version) for a very cheap if not suspicious price. Is there any fake ceramic chip out there? And quick dipping test with acetone still valid for today's fake chip or Chinese fakers learned something new?


Everything can be faked even ex-girlfriends. I know about that last one all too well.


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## FritzS

Spektykles said:


> Hi, somebody offered me a pair of used AD797SQ (ceramic DIP version) for a very cheap if not suspicious price. Is there any fake ceramic chip out there? And quick dipping test with acetone still valid for today's fake chip or Chinese fakers learned something new?



Is there any difference hear or measure able?
Or by other OPAs between DIP and metal can version?


----------



## raoultrifan

Given that a standard AD797 costs about 10 USD at Mouser and a ceramic AD797SQ costs 4 USD on eBay, I kinda think there are fakes out there.

I will if there's a resistance between some 2 pins at my AD797 (non-SQ) at home, although...an active circuit that tests and measures the noise might be better.


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## Spektykles

Anyway i just bit the bullet and took it anyway, gonna try it at home versus my normal AD797ANZ one. If its real, then the fact its packaged in ceramic and non-RoHS made it superior than plastic RoHS one (lead n heavy metal maybe bad for your brain but good for your ear  )


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## raoultrifan

Being ceramic doesn't means it will sound better, instead it is military grade and will have a better temperature operation range.
However, given the higher price of the SQ, I'm sure the Q&A is more strict than on regular plastic DIP8 opamps, so in real tests & measurements, an SQ might actually measure a bit better than ANZ.


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## LaughMoreDaily

Spektykles said:


> Anyway i just bit the bullet and took it anyway, gonna try it at home versus my normal AD797ANZ one. If its real, then the fact its packaged in ceramic and non-RoHS made it superior than plastic RoHS one (lead n heavy metal maybe bad for your brain but good for your ear  )


I once tried a Ceramic from China and it was crap. Try and buy it from any other country.


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## LaughMoreDaily

My favourite opamps right now: OPA1692 and ADA4075-2ARZ* and you?*


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## LaughMoreDaily

raoultrifan said:


> Given that a standard AD797 costs about 10 USD at Mouser and a ceramic AD797SQ costs 4 USD on eBay, I kinda think there are fakes out there.
> 
> I will if there's a resistance between some 2 pins at my AD797 (non-SQ) at home, although...an active circuit that tests and measures the noise might be better.


Too many fakes, unfortunately. If they can't fake it perfectly they might as well stop. Lol. Wait, then it's not a fake right?


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## raoultrifan

I will try to measure some resistance between AD797 pins and see if I can get something.


----------



## Mad Max

LaughMoreDaily said:


> My favourite opamps right now: OPA1692 and ADA4075-2ARZ* and you?*


ADA4075 rocks, I wish it came in MSOP form.
I want to do a comparison between 4075 and AD8512, see if 8512 is worthy for some mods I have planned.  8512 does get an MSOP variant.


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## FritzS

LaughMoreDaily said:


> I once tried a Ceramic from China and it was crap. Try and buy it from any other country.


The AD797 Ceramic DIP is officially out of production and out of stock, the danger for fakes is very great!
https://www.analog.com/en/products/ad797.html#product-discussions
https://www.digikey.com/en/product-...97-low-noise-distortion-operational-amplifier
https://eu.mouser.com/Search/Refine?Keyword=ad797


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## CoiL (Feb 24, 2019)

LaughMoreDaily said:


> My favourite opamps right now: OPA1692 and ADA4075-2ARZ* and you?*


On my DAP - 2x ADA4897-1ARZ (80mA per channel)
On my desk setup - OPA2228PA

Maybe going to try Your favourites in future when I get bored...


----------



## scruffy1

back to the party, i apologise that this is a cut'n'paste from my review at massdrop, but they are a completely different cohort :

i'm currently rocking a burson v5 courtesy of massdrop's irresistible offer, although i didn't try hard to resist really

this was put into my asus xonar hdav, replacing the burson v5i which had replaced a dual mounted opa627 which was my first opamp to "roll" the supplied one in the card... and thus do addictions begin

i spent probably little more than a few hours thus far with it, running flac files from the home theatre to a nad d3020 which drives a pair of wharfedale 10.1's and a 10.gx 10" active sub, essentially a room appropriate 2.1 system which purists would define as "entry level hifi" 

compared to the v5i, i initially thought it sounded a bit "thin" in comparison, but eventually realised that what i thought was less sound was actually more distinct separate sounds without any indistinct filling padding the gaps 
the soundstage is as wide as the v5i, but the mix seems to be much flatter across the frequencies in comparison indeed, the bass seemed less pronounced, but with noticeably more attack, and even clearer than the already impressive v5i punches; midrange had the same abilities, but on further listening it became more obvious that not all tracks have the same effect - and it slowly dawned on me that i was hearing variations that were likely entirely what the different engineers had intended, that weren't previously rendered that noticeable 

reproduction is different, and with a bit of readjustment for that, better for the most part- there are things in the music that i have never noticed before (or hadn't been able to notice might be a better interpretation), and all the components of the mix are just "there" clearly and in a balanced way that is not like i had previously been hearing them, although the v5i was a very happy option for listening too

my only complaint would be that some of my well listened tracks were revealed to have deficiencies - the flac rip of miles davis' "flamenco sketches" quite obviously showed the background noise of the original vinyl, which was a new discovery, and bowie's "life on mars" seemed to breathe like there was some weird compression happening - but i confess the volume was ramped beyond my usual listening levels for that one, and maybe the hardware needs a period of burn in to fully do its stuff (and that was about the third track i played after fitting the opamp)

i am quite happy to admit that i'm not sure that burn in is actually a thing, but time will tell if those tracks improve, or possibly i get better at ignoring any deficiencies and instead just hear the music 

overall, the v5 is a distinct step up from the v5i, which i was sorta expecting, but it took me by surprise anyway 
the v5i is no slouch, but i'm a contented buyer of its big sibling so far 

my only problem will be that i know the v6 is out there, and even more problematic, i know there's 2 variations of it... and we all know how that ends once you've got the itch


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## Spektykles

Here is my AD797SQ received a few days ago. Can anybody lookup and find a pic of the real one and compare?
I put them into pure acetone for about 5hrs. No dynasolve or x acto knife for some deep scratch test, although i will get one.


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## Themilkman46290

Spektykles said:


> Here is my AD797SQ received a few days ago. Can anybody lookup and find a pic of the real one and compare?
> I put them into pure acetone for about 5hrs. No dynasolve or x acto knife for some deep scratch test, although i will get one.


Did the acetone do anything? If they are ceramic then actetone shouldnt do anything. Did you test them?


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## Spektykles

Themilkman46290 said:


> Did the acetone do anything? If they are ceramic then actetone shouldnt do anything. Did you test them?


At first it looked darker but after acetone its gray-ish, i shot the pic after acetone test.


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## Themilkman46290

Any changes in performance? What are you trying to figure out by doing the acetone soak? I thought acetone was for stripping some plastic away so ceramic would need something alot stronger


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## Spektykles

Themilkman46290 said:


> Any changes in performance? What are you trying to figure out by doing the acetone soak? I thought acetone was for stripping some plastic away so ceramic would need something alot stronger


Obviously stripping away "fake" marking if there is any. It sounds a bit different to my ANZ and one of them has a thump when powered on.


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## Themilkman46290 (Mar 6, 2019)

Spektykles said:


> Obviously stripping away "fake" marking if there is any. It sounds a bit different to my ANZ and one of them has a thump when powered on.


Well i work with ceramics, its tough stuff, most acids wont do much, but Hydrogen Flouride might do the trick, but i think that would eat the metal too, it will be pretty difficult to open up. the circuitry is microscopic so not sure how you could without completely damaging it then you wouldnt be able to see whats in it, maybe using a ceramic diamond file in theory you could file the edges until you get to the division and chip/crack it off


----------



## Spektykles

Well, i talked to some friend who know a bit of AD stuff. He said AD never marked the military qualified version of AD797 as AD797SQ but instead long boring model number as 5962-9313301MPA. So AD797SQ just a fake name. So the one i have is definitely fake.


----------



## yurt28

If you go to ad.com and read their documentation you'll notice that "SQ" is conisdered their flagship  line number on all amps they sell, by the way Single will always sound better than dual because of direct passage +% output is bypassed which brings higher latency. About the military grade AD did make a ton of those types of all models for extremely cold areas where transformers would sit out in 0 degree tempatures,  but I dont know about 797 if they did not?


----------



## Spektykles (Mar 7, 2019)

Yup, AD never made an "SQ" version for AD797, instead they put a bunch of number as model #.
Then What is the thing I received? NE5534 remarked?


----------



## Ivan TT

These are military spec AD797, but if you are still not a believer I’m happy to offer them a new home


----------



## docentore (Mar 8, 2019)

Folks, I'm looking for single channel op-amp to replace OPA551 in Pmillet's NuHybrid amp.
Operating V: 24V
Unity gain stable
Powerful enough for planars

I have tested few myself but in terms of SQ OPA827 wins with the OPA551 but the latter outputs more cuurent.
If there only was single channel version of AD8397


----------



## raoultrifan

docentore said:


> [...] I'm looking for single channel op-amp to replace OPA551 in Pmillet's NuHybrid amp.
> [...]



Why?!?


----------



## docentore (Mar 8, 2019)

raoultrifan said:


> Why?!?


Because I can, and bacause I believe that there might be a better option to power my planar headphones.

You dont believe uin upgrades? I find this question very unusual as coming from one of the most active members in this thread recently


----------



## raoultrifan

Of course I can, but only if it really improves something like THD, noise...anything. But in this case you will get no improvement at all, you might just cause issues.

I assume you were reading Pete's comment from his website: _"You can substitute your favorite opamp or buffer for the OPA551.  It needs to support a 24V power supply, and be unity gain stable.  Other than that it's up to you"_. Given the fact that you need to drive planars, you really need those fully 200mA from this very good output buffer OPA551. However, if someone here can provide a replacement suggestion in this scenario, just take care to any possible oscillations, so an oscilloscope might be helpful. Of course, the output RC filter could be adjusted to stop the oscillations, if really needed.

Here's the schematic: http://www.pmillett.com/nuhybrid.html
Here's OPA551 datasheet: http://www.ti.com/lit/ds/symlink/opa551.pdf.

Like Pete said, you could probably try some workarounds with the BUF634, but he already stated that lowerst harmonics, in given schematic, are achieved with OPA551 and not with BUF634. Please, have in mind that you're trying to swap a 200mA opamp!

In NuHybrid, if you really want to increase its performance or change sound flavor in any way, you might try to swap the tube, but not the output stage opamp. This my personal opinion, after swapping several opamps in many amplifiers and DACs. At this moment I have about 100 opamps in my self, from 5532 to MUSES01/02 and Burson SS V5/V6.


----------



## docentore

raoultrifan said:


> Of course I can, but only if it really improves something like THD, noise...anything. But in this case you will get no improvement at all, you might just cause issues.
> 
> I assume you were reading Pete's comment from his website: _"You can substitute your favorite opamp or buffer for the OPA551.  It needs to support a 24V power supply, and be unity gain stable.  Other than that it's up to you"_. Given the fact that you need to drive planars, you really need those fully 200mA from this very good output buffer OPA551. However, if someone here can provide a replacement suggestion in this scenario, just take care to any possible oscillations, so an oscilloscope might be helpful. Of course, the output RC filter could be adjusted to stop the oscillations, if really needed.
> 
> ...



Thanks for your reply. 

I cannot swap the tube as this is unique and one of its kind. Simply there is nothing to replace it with 
I believe Pete Millett when puting this amplifier together had cost and part avaibility as 2 most important factors. Hence my believe that there has to be something better, altough I find it good sounding as it is. Just the way I am, if the IC is is the socket it means it could be upgraded


----------



## raoultrifan

There is something, a solid-state opamp (DIY), but it's big in size. It would be something solid-sate, but not sure it will oscillate or not, so a scope is still needed: https://www.soundskulptor.com/en/proddetail.php?prod=SK99. Given the powerful BD139/BD140 you will have no issues with driving planars.

If you really want to be frugal on this, maybe you'd like to email Pete and nicely ask him if really worth spending the money on those SS opamps. I mean, specs are great, I would probably no hesitate to try them out, but still...36 EUR + shipping for 2 opamps, so it could get over 50 EUR in the end.


----------



## docentore

raoultrifan said:


> There is something, a solid-state opamp (DIY), but it's big in size. It would be something solid-sate, but not sure it will oscillate or not, so a scope is still needed: https://www.soundskulptor.com/en/proddetail.php?prod=SK99. Given the powerful BD139/BD140 you will have no issues with driving planars.
> 
> If you really want to be frugal on this, maybe you'd like to email Pete and nicely ask him if really worth spending the money on those SS opamps. I mean, specs are great, I would probably no hesitate to try them out, but still...36 EUR + shipping for 2 opamps, so it could get over 50 EUR in the end.



I tried to engage with Pete and others on the build thread but without much success and feedback. Don't really want to email himself as he reads the thread.

Thanks for suggesion with the SS opamp, I'll try that. Also I'm considering converting the AD8397 dual channel to single channel.


----------



## raoultrifan (Mar 8, 2019)

AD8397 might worth a try, why not...just take care of the DYI dual-to-single adapter. I did such DIY adapter myself last year: https://www.head-fi.org/threads/new...mp-rollers-dream.860882/page-17#post-14034674, but only half of the opamp is working, of course.


----------



## docentore

raoultrifan said:


> AD8397 might worth a try, why not...just take care of the DYI dual-to-single adapter. I did such DIY adapter myself last year: https://www.head-fi.org/threads/new...mp-rollers-dream.860882/page-17#post-14034674, but only half of the opamp is working, of course.


Thanks. I was thinking of either doing it on 3 different ways:
1. same as you - 2xAD8397 used
2. with "unused" amp terminated - http://www.ti.com/lit/an/sboa204a/sboa204a.pdf - 2xAD8397 used
3. creating DIY adapter dual2single - 1xAD8397 used


----------



## Spektykles (Mar 8, 2019)

Interesting to know that my "fake" AD797SQ is now behaving like genuine one, atleast in thermal perspective. It heats up very fast like a true AD797 (i guess oscillating), my genuine ANZ also heat up the same, but the SQ has more gain and sounds very similar to 5532. Took a blind test with my AD797ANZ and LME49990 (similar to 797) and i can pick it SQ out with just one ear. Anyone know what ceramic opamp is unstable and oscillating like hell like AD797? I think the Chinese tried to mimic it.


----------



## carlmart

But why don't you try to stabilize it? 

Wouldn't a bypass cap between the power pins and two more bypass caps to ground, very close to V+ and V- pins improve that?

There must be recipes to google for with people who solved the AD797 instability issues.


----------



## Ivan TT

I had massive issues with AD797 (B grade, genuine), overheating, sweeping noises, random RFI. Tried every suggestion from the datasheet and all the forums to no avail, solved it eventually by adding RC filter at about 450kHz (or higher sorry don’t remember exact values) to the output. Dead silent, cool and sounds awesome as it should!


----------



## Spektykles (Mar 8, 2019)

carlmart said:


> But why don't you try to stabilize it?
> 
> Wouldn't a bypass cap between the power pins and two more bypass caps to ground, very close to V+ and V- pins improve that?
> 
> There must be recipes to google for with people who solved the AD797 instability issues.


My amp using single dual opamp design and the ground point provided on PCB way too far from the opamp itself so its hard to me for some proper bypass. Anyway i will try to improvise.


----------



## scruffy1 (Mar 8, 2019)

docentore said:


> Thanks for suggesion with the SS opamp, I'll try that. Also I'm considering converting the AD8397 dual channel to single channel.



fwiw i have tried the burson v5i and then the v5 in my xonar hdav in the primary slot, and the bursons are both an upgrade on the dual opa627 i had substituted fom the default opamp

and the v5 is transparently better than the v5i - there's also 2 flavours of v6 (classic and vivid); the good news being that due to the new releases the v5 versions have dropped in price, and can be had cheaper than before at burson's site, or on occasion via massdrop, where i picked up the v5 very recently


obviously you have to test them in your own hardware, but both the burson offerings i have bought have been a very worthwhile upgrade

ooee !  not again !
https://www.massdrop.com/buy/burson-audio-v6-classic-op-amps


----------



## FritzS

Ivan TT said:


> I had massive issues with AD797 (B grade, genuine), overheating, sweeping noises, random RFI. Tried every suggestion from the datasheet and all the forums to no avail, solved it eventually by adding RC filter at about 450kHz (or higher sorry don’t remember exact values) to the output. Dead silent, cool and sounds awesome as it should!


Have you implement the recommend caps?
CL (in NFB path); Fig. 45, 46; Table 8; the bypass caps V+ (pin 7) V- (pin 4).
https://www.analog.com/media/en/technical-documentation/data-sheets/AD797.pdf


----------



## Ivan TT (Mar 9, 2019)

FritzS said:


> Have you implement the recommend caps?
> CL (in NFB path); Fig. 45, 46; Table 8; the bypass caps V+ (pin 7) V- (pin 4).
> https://www.analog.com/media/en/technical-documentation/data-sheets/AD797.pdf


Tried *every* suggestion from the datasheet.
Well, only could source 49pF COG caps (not 50pF) and to be honest the circuit had a digital board right above AD797B, and it's not RFI/EMI hardened.
Also it was configured G=1, which did not help with stability.
But the solution above works perfect, listening to music as I type, AD797B is the best opamp ever.
PS: I actually believe Fig. 45, 46; Table 8 suggestions INCREASE susceptibility to oscillation as they effectively decompensate AD797


----------



## raoultrifan

@Ivan TT what was the solution that worked out for you, please? The NFB caps or the bypass caps or increasing the gain?


----------



## Ivan TT

raoultrifan said:


> @Ivan TT what was the solution that worked out for you, please? The NFB caps or the bypass caps or increasing the gain?


None of the above.
RC LPF filter on the output, cutoff frequency around 500kHz, ideally using film caps.


----------



## docentore

raoultrifan said:


> AD8397 might worth a try, why not...just take care of the DYI dual-to-single adapter. I did such DIY adapter myself last year: https://www.head-fi.org/threads/new...mp-rollers-dream.860882/page-17#post-14034674, but only half of the opamp is working, of course.


Unfortunately the opamp is oscilating (I think), heats up very quickly and stays hot. I've tried adding 0.1uF or 10uF cap (different sources different recs)  to power pins but still heats up.


----------



## FritzS

Something else must have gone wrong. In my DIY headphone amplifier the developers had originally used the LM6171. The LM6171 behaves like a "diva" when it comes to oscillation inclination.
Between the output of the OPA and the driver stage there is a ferrite bead. This prevents the LM6171 from oscillating. This is also true for many other OPAs.
I've tried a lot of OPAs, no oscillation has occurred. AD797 was the best till today!

Translated with www.DeepL.com/Translator


----------



## FritzS

Ivan TT said:


> Tried *every* suggestion from the datasheet.
> Well, only could source 49pF COG caps (not 50pF) and to be honest the circuit had a digital board right above AD797B, and it's not RFI/EMI hardened.
> Also it was configured G=1, which did not help with stability.
> But the solution above works perfect, listening to music as I type, AD797B is the best opamp ever.
> PS: I actually believe Fig. 45, 46; Table 8 suggestions INCREASE susceptibility to oscillation as they effectively decompensate AD797



If gain 1 or -1 please look at page 13, 14, 15 too.


----------



## nesty

Spektykles said:


> Here is my AD797SQ received a few days ago. Can anybody lookup and find a pic of the real one and compare?
> I put them into pure acetone for about 5hrs. No dynasolve or x acto knife for some deep scratch test, although i will get one.



@Spektykles , you have a genuine AD797SQ you see they have a plant in the Philippines. For that reason it's laser printed underneath. That ceramic package is for high temp environment.


----------



## Spektykles

nesty said:


> @Spektykles , you have a genuine AD797SQ you see they have a plant in the Philippines. For that reason it's laser printed underneath. That ceramic package is for high temp environment.


But why they are so different for me on SQ? Totally different from the ANZ. Also the fact AD made those AD797 "military-graded" with different name and marking, not "AD797SQ".


----------



## Ivan TT (Mar 16, 2019)

Spektykles said:


> Also the fact AD made those AD797 "military-graded" with different name and marking, not "AD797SQ".


AD797 has been in production for a few decades now, but it's possible to find old datasheet that clearly mentions cerdip package (and does not have a mention of more modern SOIC variant):
http://www.om3bc.com/datasheets/ad797.pdf
AD had a range of military grade opamps that they coded completely differently, those I believe had even better specs (at least as far the temperature goes), but were just re-marked, no difference in actual design.


----------



## NNewman

Hello. Sorry for the silly question, but why everybody solderring an electrolytic capacitors to the OpAmp pins? Why not taking a good "paper in oil" or smthg like that, that are much more sound friendly?


----------



## Rroff

NNewman said:


> Hello. Sorry for the silly question, but why everybody solderring an electrolytic capacitors to the OpAmp pins? Why not taking a good "paper in oil" or smthg like that, that are much more sound friendly?



Physical space is one consideration also they are often there for high frequency bypassing, etc. which IIRC isn't a strength of paper in oil types also there is generally a sweet spot for stability ESR wise - going too low actually isn't necessarily a good thing especially depending on proximity to some regulators.


----------



## raoultrifan

NNewman said:


> Hello. Sorry for the silly question, but why everybody solderring an electrolytic capacitors to the OpAmp pins? Why not taking a good "paper in oil" or smthg like that, that are much more sound friendly?


Paper-oil caps are for audio-use, for power-use MLCC, tantalum or high ripple & low ESR caps are more appropriate. For opamp power pins bypassing you need to respect manufacturer's recommendation (usually MLCC and low ESR electrolytic).


----------



## LaughMoreDaily

Ivan TT said:


> AD797 has been in production for a few decades now, but it's possible to find old datasheet that clearly mentions cerdip package (and does not have a mention of more modern SOIC variant):
> http://www.om3bc.com/datasheets/ad797.pdf
> AD had a range of military grade opamps that they coded completely differently, those I believe had even better specs (at least as far the temperature goes), but were just re-marked, no difference in actual design.


I just bought an Audio Jade AD797BR. Is that the best one (BR)? I heard it is?


----------



## Ivan TT

LaughMoreDaily said:


> I just bought an Audio Jade AD797BR. Is that the best one (BR)? I heard it is?


I never bought their's so cannot comment, sorry.
I sourced mine directly from AD and arrow.com, 100% genuine but refreshingly expensive.


----------



## LaughMoreDaily (Mar 26, 2019)

Ivan TT said:


> I never bought their's so cannot comment, sorry.
> I sourced mine directly from AD and arrow.com, 100% genuine but refreshingly expensive.


My AJ opamp was also expensive. Almost $30. I should have bought it from a better source but Ebay works better for me. But too many fakes...

The one I ordered previously from someone else on Ebay was defective and they were like, "We will just send you another." I knew right then and there it had to be fake since Audio Jade's is $30 and I paid $15.


----------



## Ivan TT

LaughMoreDaily said:


> The one I ordered from someone else was defective and they were like, "we will just send you another." I knew right then and there it had to be fake since Audio Jade's is $30.


Fair enough, unless you buy directly from AD or official distributor it's a bit of a lottery.
I have some horror stories to tell about 797s and 627s I've got from taobao, at least they were dirt cheap.
I also bought some genuine 797s from tao and ebay, dirt cheap too (being AD797 funboi I can tell genuine from fake just from sonic signature).
I do eye those ceramic cased AD797SQ ones on tao, the only issue I will struggle to fit them in my DAP as they are slightly taller compared to plastic DIP.
Having said that I don't mind playing this lottery at all, actually just bought black/white 797s from ebay AND ali, from my research AD used this colour scheme in early 2000s, so may be NOS, may be fake.


----------



## endia

LaughMoreDaily said:


> My AJ opamp was also expensive. Almost $30. I should have bought it from a better source but Ebay works better for me. But too many fakes...
> 
> The one I ordered previously from someone else on Ebay was defective and they were like, "We will just send you another." I knew right then and there it had to be fake since Audio Jade's is $30 and I paid $15.



did you pay $15 for one or two?

100% genuine one is $12 on arrow.com;
https://www.arrow.com/en/products/ad797brz-reel7/analog-devices


----------



## NNewman

LaughMoreDaily said:


> My AJ opamp was also expensive. Almost $30. I should have bought it from a better source but Ebay works better for me. But too many fakes...
> 
> The one I ordered previously from someone else on Ebay was defective and they were like, "We will just send you another." I knew right then and there it had to be fake since Audio Jade's is $30 and I paid $15.


Hello. Audio Jade is a good and trusted source. I personally made several orders there and the quality was always on top.


----------



## LaughMoreDaily (Mar 27, 2019)

endia said:


> did you pay $15 for one or two?
> 
> 100% genuine one is $12 on arrow.com;
> https://www.arrow.com/en/products/ad797brz-reel7/analog-devices


I paid $15 for one Non-BR AD797 (defective) with shipping. That link you posted is a great one! It has free shipping today. My AD797BR AJ was close to $30 with shipping. It is a different type of opamp than your link.


----------



## NNewman

LaughMoreDaily said:


> I paid $15 for one Non-BR AD797 (defective) with shipping. That link you posted is a great one! It has free shipping today. My AD797BR AJ was close to $30 with shipping. It is a different type of opamp than your link.


Can you give a link to ad797br on AJ ebay page?


----------



## LaughMoreDaily

NNewman said:


> Can you give a link to ad797br on AJ ebay page?


I would search for it. It's quite easy. They put all AD797s on the same page.


----------



## Themilkman46290

I have tried a few opamps, and noticed I like the lme49720ha and lme49710ha opamps more then the rest, the only amp I have that seems better is my v5i-d. I bought the lme49720 non metal can version and didn't like it as much and I was curious to try something else in to99 case, could you guys tell me what are the best opamps in to99 case?


----------



## LaughMoreDaily

Themilkman46290 said:


> I have tried a few opamps, and noticed I like the lme49720ha and lme49710ha opamps more then the rest, the only amp I have that seems better is my v5i-d. I bought the lme49720 non metal can version and didn't like it as much.


I'm one of those dummies who has bought every other opamp except the v5id. I've spent more money than its cost times two or three or four times yet I still havent bought it. Weird.


----------



## NNewman

Themilkman46290 said:


> I have tried a few opamps, and noticed I like the lme49720ha and lme49710ha opamps more then the rest, the only amp I have that seems better is my v5i-d. I bought the lme49720 non metal can version and didn't like it as much and I was curious to try something else in to99 case, could you guys tell me what are the best opamps in to99 case?



Opa627SM...
Opa627BM

But they costs...
You can try opa111AM or opa111bm ... They are quite cheap and 100% original from AudioJade. More cheaper are opa445BM...  Chinees ORIGINAL amp9920AM is also an extraordinary piece of gear...
There are lots of others, but all the above I have or tried for a continuous period of time.


----------



## scruffy1

it's beautiful (the v5i)

massdrop do it cheap  - twice now

i reckon it's better in the xonar hdav than the "big" v5 is, and will swap it back in shortly... unless the comparison is unfair because i have since the same time as i've started trying out the v5 have been listening to a valve headphone amp, and my expectations have lifted substantially


----------



## Themilkman46290 (Apr 5, 2019)

Was hoping you guys could help me out a bit, I was recently desoldering my favorite opamps (2×lme49710ha) so I can fix it to the proper adapter and 2 legs fell off (don't really understand how)  I have tried the replacements but they really are not the same, I was thinking to give the muses02 a try but I would need to pay about $95 each and I don't feel it's really worth it, is there anything in the cheaper range that might have a similar sound to the dual lme49710ha? 

And yea I checked the 627bm but that's allot more expensive


----------



## scruffy1

see above

a pair of v5i's from massdrop (when available) are worth a listen


----------



## Themilkman46290

scruffy1 said:


> see above
> 
> a pair of v5i's from massdrop (when available) are worth a listen


   the shipping alone would be the price of a nice opamp, I live in eastern Europe, and they are too big, cost too much, I do like the v5i but I all ready have one

Any other suggestions?


----------



## scruffy1

i like opa627's too, but am uncertain if that's an option for you


----------



## raoultrifan

Themilkman46290 said:


> [...]I was thinking to give the muses02 a try but I would need to pay about $95 each and I don't feel it's really worth it[...]


ProFusion PLC UK, you pay online and they ship via DHL within Europe. i purcahsed 8 x MUSES01 from them and 2 x MUSES02 plus several other electronic components.

Optionally, if you're interested into V6 Classic, ping me and I might help.


----------



## HeyManslowdown97 (Apr 6, 2019)

Ivan TT said:


> I never bought their's so cannot comment, sorry.
> I sourced mine directly from AD and arrow.com, 100% genuine but refreshingly expensive.



“Refreshingly Expensive” isn’t that  oxymoronic??

 Why not just source it from AE or player.ru I hear they have great gear for cheap (homemade) and engineering on there for trading purposes is top notch! (I got a Zishan Ak4497 for ground experiments on there) It’s great.

Also why  “Military Grade” AD 797 with even “better specs”?? Wouldn’t you need proper  documentation to purchase those genuine parts as a US military contractor??



Spoiler



https://dfw.cbslocal.com/2018/01/25/texas-man-smuggling-circuits-china-russia/amp/


----------



## Ivan TT (Apr 6, 2019)

HeyManslowdown97 said:


> “Refreshingly Expensive” isn’t that oxymoronic??


"Refreshingly stale" would be, but even if it is??
A pair of AD797B from arrow.com is just under $20, about 10 times above the going rate for other opamps, but on the second thought I have bought Bursons and Muses opamps which were _ridiculously_ expensive in comparison.


HeyManslowdown97 said:


> Why not just source it from AE or player.ru I hear they have great gear for cheap (homemade) and engineering on there for trading purposes is top notch! (I got a Zishan Ak4497 for ground experiments on there) It’s great.


I suppose "homemade" AD797 would be an euphemism for "fake" 
I wanted to insure that I'm buying 100% genuine brand new opamps from the same batch as for me it was mission critical.
I do buy opamps from ebay and AE (player.ru does not sell opamps AFAIK), including AD797 but it's a lottery as stated above.
Fresh example from yesterday: ordered AD797B from AE where lot clearly advertised as AD797*B* (including photos), they sent me AD797*A *- already opened a dispute.


HeyManslowdown97 said:


> Wouldn’t you need proper documentation to purchase those genuine parts as a US military contractor??


I would have NO idea, but I trust that authorised distributors are law-abiding and have appropriate control systems in place.
Having said that neither of AD797 grades are specced as military as its military grade has completely different code, 5962-9313301MPA (which comes in CERDIP package and is no longer in production AFAIK anyway).


HeyManslowdown97 said:


> Also why “Military Grade” AD 797 with even “better specs”??


As to why, AD797A produces 1.1-.1.2 mV DC offset, AD797B - 0.5mV, while it appears insignificant I don't mind 6dB reduction (or lack of clicks/pops when plugging headphones in). But CERDIP package would require separate PCB to mount opamps on and I doubt there would be much gain especially since bypass caps would end up miles away.


----------



## HeyManslowdown97 (Apr 6, 2019)

Ivan TT said:


> "Refreshingly stale" would be, but even if it is??
> A pair of AD797B from arrow.com is just under $20, about 10 times above the going rate for other opamps, but on the second thought I have bought Bursons and Muses opamps which were _ridiculously_ expensive in comparison.
> 
> I suppose "homemade" AD797 would be an euphemism for "fake"
> ...




Haha, I saw a guy mod a Zishan with two CMOY pioneering with a Opa1622 packaged in VSSON from China to power a Zishan juxtaposed already established series PCB to run it parallel and waste valuable real estate that made no sense since you still need the series.

I dropped two Opa2189 SOIC in lpf which is MUX-friendly and also CMOS. Personally I find CMOS on their own exhausting to listen but powering a great sounding amp is amazing.

And here’s the kicker. The Opa2189 makes the digital fitlers pop and helps adjust electronical power issues that you may have with counterfeit circuits but of course folks go for the eye candy pics instead of listening to their ears. 

I agree with you on the MUSES and Burson on being ridiculously expensive. I will say though the “Muse” caps are great sounds and you don’t have to break the bank for them. As far as “expensive” that’s all  based upon demand, “hype” and marketing. It can also be relative when not comparing them to other op amps. It is however a huge difference if you are scaling it up as a major manufacturer putting out a device. 

Burson is just wayyyy overpriced. I’m sure they are nice but is it night and day (I doubt it)


----------



## raoultrifan (Apr 7, 2019)

HeyManslowdown97 said:


> [...]
> 
> I agree with you on the MUSES and Burson on being ridiculously expensive. I will say though the “Muse” caps are great sounds and you don’t have to break the bank for them. As far as “expensive” that’s all  based upon demand, “hype” and marketing. It can also be relative when not comparing them to other op amps. It is however a huge difference if you are scaling it up as a major manufacturer putting out a device.
> 
> Burson is just wayyyy overpriced. I’m sure they are nice but is it night and day (I doubt it)



I've used 4x MUSES01 &  2x MUSES02 inside my ASUS Essence One MKii combo; I got a more pleasant sound with a bigger soundstage, also microdetails seemed better. I have removed when I did some tests and realised than MUSES01 used in I/V stage of this DAC introduced unwanted harmonics (not much, but still there). I had replaced the 6 opamps with NE5532 and LME49720.

I've used MUSES02 and SS V6 Classic inside my Matrix HPA-3B headamp and I got both better measurements and lower background noise over the originals LME49860. For HPA-3B both MUSES02 and SS V6 are totally recommended (it's voltage amplification stage in there). Also, MUSES8920 are OK as well.

Can you imagine a better opamp for the gain-stage of Objective2 than the original NJM2068? Well, with SS V5 I got an even lower background noise (tested with ears and scope @6.5X of gain).

If it worth the price paid for solid-states opamps is not my call, but all I know is that if you want no opamps in audio signal path, then you can replace them all with solid-state devices from BURSON or similar manufacturers. Although, I'm aware than >90% of existing audio records on Terra are done through at least a pari of 5532 opamps. 

L.E.: Given the fact that these solid-state opamps are built in a very small quantity, and given the high quality transistors and "1% precision" resistors inside, I don't think anyone should call such "opamps" as being overpriced. Let's agree to call them expensive and just that. Feel free to read my review and inside pics of the SS V6 and you'll see how internal PCB and components look like.


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## HeyManslowdown97 (Apr 7, 2019)

raoultrifan said:


> I've used 4x MUSES01 &  2x MUSES02 inside my ASUS Essence One MKii combo; I got a more pleasant sound with a bigger soundstage, also microdetails seemed better. I have removed when I did some tests and realised than MUSES01 used in I/V stage of this DAC introduced unwanted harmonics (not much, but still there). I had replaced the 6 opamps with NE5532 and LME49720.
> 
> I've used MUSES02 and SS V6 Classic inside my Matrix HPA-3B headamp and I got both better measurements and lower background noise over the originals LME49860. For HPA-3B both MUSES02 and SS V6 are totally recommended (it's voltage amplification stage in there). Also, MUSES8920 are OK as well.
> 
> ...



It’s funny you mentioned the high quality transistors as I always bring up Moore’s Law with many audiophiles and they don’t get the principle behind microprocessing and WHY it’s hard to replicate original chips without a huge budget and why patent laws to protect them from foreign jurisdictions that don’t follow international IP Laws like China is important for quality control and things like National Security.

(It’s because of this that I can really appreciate how in-depth your review is in regards to Bursons SS with magnified pics to illustrate their quality ) 

It’s just my opinion. Bursons justifies their price by saying that it’s “R&D” cost over a span of years of research per op amp and I'm sure because they aren't a huge company so it cost a lot to scale up on production.

I agree with you about records and gear. I've noticed that the better the op amps shows flaws in some recordings. It actually makes me sad because even the crappiest new records are made better because of digital and DAW advancements.

The solid state argument. I really can't say if it's better than tube amps as I don't have ANY experience in them.

Op amps are also used in effects pedal in guitars and yet there is also software that can achieve almost exact sound fx so even in that argument I have no experience but algorithms in software are getting pretty close if not better than physical pedals no matter what “stock” op amp is in a soundcard. The stock tend to be cheaper since soundcard makers don’t want to pay a premium price on a op amp since it would effect on price on the customer so they will often go on the cheap end that would explain noticing a considerable different when op amp rolling.

There is so many divisions of “sound” these days like games prefer certain sound cards for multi-channel purposes so it becomes very complained and it isn't fair to say that one all purpose amp solves everyone’s needs or on every application you intended to use a particular one!

My schtick with Bursons Is that I refuse to pay for them. I can't justify paying an extra 100+ on say two avids v6 when the difference isn't as noticeable with their competitors who have been at it longer and more experienced with a larger line and with more options to choose from. So I can get 30+ for the price of two Burson V6 Avid or classic. I’d rather spend that money differently. Just my opinion though.


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## LaughMoreDaily (Apr 7, 2019)

Has anyone tried the M3 Customs (Phillipines)  opamps that are spin offs of the AD8066/Dibil? I want to buy the best ones as they have four now.

If I bought all four (which may be a waste of money to do) it would be about $75 plus shipping.


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## raoultrifan

One pair of SS V6 duals costs about 130 USD, a pair of dual Sparkos costs 160 USD and a pair of Sonic Imagery 994Enh-Ticha Dual 188 USD! So, quite expensive, although the Burson still provides the "cheapest" high-end solid-state opamps, after all.

BTW, I asked once NJR/JRC why the MUSES01/02 are so expensive? They nicely told me that it's not just a simple marketing gimmick, but more related to the production costs, because MUSES01/02 (and newer 03) are manufactured on their own dedicated production line, apart from regular opamps, and using a different Q&A process. All of the above are delaying a lot the time to manufacture each of these products, hence the much increased price.

A well-designed DAC or amplifier, with a very good ground plane and a low-noise power supply should perform admirable with most audio , starting from NE5532/5534 (also, I recommend JRC5532DD/JRC5534DD, which outperforms the NE5532/NE5534 in all aspects) to OPA1622, OPA627, AD797 or similar.


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## LaughMoreDaily

Themilkman46290 said:


> I have tried a few opamps, and noticed I like the lme49720ha and lme49710ha opamps more then the rest, the only amp I have that seems better is my v5i-d. I bought the lme49720 non metal can version and didn't like it as much?



What other opamps did you compare those with?


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## Themilkman46290

LaughMoreDaily said:


> What other opamps did you compare those with?


Ad8066,ad825,opa2134,opa2132,ad823,muses8920,lt1364,opa827,lme6172, the ad825 and 823 would be my favorites aftar the v5i and lme49710ha


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## HeyManslowdown97

raoultrifan said:


> One pair of SS V6 duals costs about 130 USD, a pair of dual Sparkos costs 160 USD and a pair of Sonic Imagery 994Enh-Ticha Dual 188 USD! So, quite expensive, although the Burson still provides the "cheapest" high-end solid-state opamps, after all.
> 
> BTW, I asked once NJR/JRC why the MUSES01/02 are so expensive? They nicely told me that it's not just a simple marketing gimmick, but more related to the production costs, because MUSES01/02 (and newer 03) are manufactured on their own dedicated production line, apart from regular opamps, and using a different Q&A process. All of the above are delaying a lot the time to manufacture each of these products, hence the much increased price.
> 
> A well-designed DAC or amplifier, with a very good ground plane and a low-noise power supply should perform admirable with most audio , starting from NE5532/5534 (also, I recommend JRC5532DD/JRC5534DD, which outperforms the NE5532/NE5534 in all aspects) to OPA1622, OPA627, AD797 or similar.



Great stuff and good to know about a well designed DAC and how op amps performances and with very good ground plane and power supply. I know the importance of this!!! Great Basic electrical principles go a long way! 

Will try the JRC5532DD/JRC5534DD but like I said I’m cheap. Haha


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## raoultrifan

HeyManslowdown97 said:


> like I said I’m cheap


Let's call this...frugality, OK? 

AD8599, AD797 should fit the bill. Also, might worth testing MUSES8920 if you don;t find it very expensive; it should work fine in I/V and LPF and VoltAmpStage.


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## scruffy1 (Apr 7, 2019)

raoul, may i jump in and pick your brains ?

i run a xonar hdav1.3 in the htpc, to a nad d3020 driving a 2.1 wharfedale setup (diamond 10.1 + 10dx)

the xonar had a dual opa627 in the primary, and then a dual v5i, which was even better (replacing the supplied LM4562NA)



the burson v5 sounds "wrong" as a component, whereas the v5i is the pinnacle of my available combinations - hard to describe, but the stage is great, but the music sounds like it has compression artefacts ("breathing" levels) - running mostly flac files

why is it so ?

and it has (2x) JRC 2114D in the secondary slots (IV); i tried a pair of ad823anz (of questionable parentage) which i thought had "better" specs than the 2114d in the situation, but the distorion was horrible - is this a reflection of my ignorant choice, or rather a confirmation that they are fake ?

is there an iv choice for the hdav that might enhance the rca out quality, or have a better synergy with the v5


as it stands i reckon the burson play is beckoning, but i am happy for the frugal alternative if such a beast is available

cheers


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## HeyManslowdown97 (Apr 8, 2019)

“the burson v5 sounds "wrong" as a component, whereas the v5i is the pinnacle of my available combinations - hard to describe, but the stage is great, but the music sounds like it has compression artefacts ("breathing" levels) - running mostly flac files.”

I actually think this makes a lot of sense and am curious as to why this is as well. I’ve experienced this “phenomena” when you mix up combinations of op amps and always wanted to know why that is??! 

@raoltrifan

Slightly off topic but I couldn’t help notice your Grados in your aviator. They make them in Brooklyn, New York (where I am from) I’ve heard nothing but great things from guys who make them.

Not really that “frugal” just new at this so I like to discover as many op amps as I can to get an overall arch of sound. My sound isn’t “fixed” per se. I’ve heard nothing but great things about Bursons. I’ve seen them on their eBay store that they offer pretty nice DACs from Gustard, etc with their op amps for a reasonable price as well!


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## raoultrifan

Hi @scruffy1, just found your post: https://www.head-fi.org/threads/the-opamp-thread.432749/page-346#post-12642543.
I can't find pics with your card; instead, I found the slim version, but this has no I/V stage and is using https://www.cirrus.com/products/wm8776/.
You need to do RMAA or ARTA tests to see what opamps are getting the lowest THD+N. After that, do listening tests.


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## scruffy1

hi raoul

thanks for your reply

the thread you are seeking is this :
https://www.head-fi.org/threads/the...ressions-thread.421890/page-354#post-12644745

to my limited comprehension, the hdav is essentially the stx - full specs and review here :
https://www.pcper.com/reviews/Gener...V-13-Deluxe-Review-Penultimate-HTPC-Soundcard

- but with provision for a 7.1 output daughter card for home theatre (which also features swappable dip sockets for all the channels), and no discrete headphone connection, which is where i thought the iv slots may have actually come into play 

from my experimentation it is clear they influence the rear rca outs (to the nad)

apologies for my ignorance,  rmaa and arta are acronyms with no prior meaning to me, but google is my friend and i will have a look
are they essentially equivalent ?

my problem is not being educated enough in electronics to interpret the spec sheets for opamps; the best i can do is see the voltage ranges at which they are rated, and then rely on reports from other users as to their virtues - that's why i am keen for practical recommendations for which choices


add to that the recent acquisition of a pam an headphone amp (with vostok and rtc "new old stock" tubes to try out), and i am overwhelmed with lovely acoustic toys to figure out; i must say tubes are another great experience but not sure better, just different and really good


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## raoultrifan

@scruffy1, based on http://nihtila.com/2017/01/08/pcm1794a-output-stage-opamp-measurements-lm4562-ne5532-and-opa2134/ I would use 5532 chips in I/V or the original JRC2114D; as per LPF, LM4562 is just fine.

Without measurements, just based on listening tests, I can't recommend you any upgrades, sorry. Reasons would be:
- lack to identify if oscillations or post-ringing occurs
- THD could increase if incompatible opmaps are used

It's all in the PCB layout and power supply rails quality, so sometimes very good and expensive opamps might work worse in some situations.


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## HeyManslowdown97

“It's all in the PCB layout and power supply rails quality, so sometimes very good and expensive opamps might work worse in some situations.” 

Man this is sooo true. I’ve come up with the same conclusion!


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## HeyManslowdown97 (Apr 9, 2019)

@raoultrifan

Hey- I really like your approach to fundamentals especially when it comes to testing for op amp performance! I had a hunch that better op amps with crappy electrical input and output actually sounds worse and I’m glad that you have confirmed it for me with your knowledge. (Save me time- hypothesizing).

When it comes to “well built” Dacs and op amps some even really great manufacturers cut corners on the smallest things like LDOs, Supply Relays, diodes, etc because adding them with licensing can add up. So a part that’s slightly cheaper like < cents adds up when mass market. Ultimately if you can gain the skill to make your own evaluation boards that’s best course of action.

(Some of the DIY Audio post and threads have amazing ideas and concept by DIYers which pretty rad in the age of the internet of things. However, some information should be taken with the a grain of salt).

I bought a multimeter but don’t know how to use it. Is there one you can recommend that checks everything (that’s preferably “frugal”  ).

I think it’s fun to learn more about this stuff but there are definitely a lot of fits and triumphs along the way. 

Honestly, in this thread I really can’t make an accurate evaluation of op amps since to-date I really don’t have top-notch gear to make an accurate assessing to what op amps to recommend to anyone only my ears to go by but I DO enjoy learning from others’. In my very limited Modding experience I’ve learned that it really humbles you (more so than what people say in threads!)


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## raoultrifan (Apr 9, 2019)

HeyManslowdown97 said:


> I bought a multimeter but don’t know how to use it. Is there one you can recommend that checks everything (that’s preferably “frugal”  ).
> 
> I think it’s fun to learn more about this stuff but there are definitely a lot of fits and triumphs along the way.



If it's a RMS-multimeter, then you could measure the AC output voltage when feeding the DAC or amp with 0dB (or -1dB) 1KHz sinewave. Usually around 2V RMS for DACs and more voltage for headamps, of course.

Also, DC-output voltage could get measured as well, no music connected, no cables connected to RCA/XLR/jack inputs. Usually if lower than 3mV of DC voltage should be fine for most 16-32 cans; for 300-600 Ohms cans it could be higher, but not more than 10-20mV.

You could get a cheap ADC like the one built-into ASUS U7, but also a cheap Behringer UMC204 or Focusrite have a good ADC inside too. Then you can start doing some RMAA and ARTA test too.

Basically, with the above simple tools you could identify some flaws in the audio equipment and, why not, some differences between opamps (when swapping them). For more in-depth analysis you need something else, at least QA401 from Quantasylum.


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## HeyManslowdown97 (Apr 9, 2019)

raoultrifan said:


> If it's a RMS-multimeter, then you could measure the AC output voltage when feeding the DAC or amp with 0dB (or -1dB) 1KHz sinewave. Usually around 2V RMS for DACs and more voltage for headamps, of course.
> 
> Also, DC-output voltage could get measured as well, no music connected, no cables connected to RCA/XLR/jack inputs. Usually if lower than 3mV of DC voltage should be fine for most 16-32 cans; for 300-600 Ohms cans it could be higher, but not more than 10-20mV.
> 
> ...




Thanks and also for recommendations as well! Just cut and paste your info to thoughts in review it later in my NOTES.

How about measure resistors, diodes. Is it the same. Im gonna have to watch some videos on how to read the multimeter. It’s such an  essential tell to keep in the tool box rather than “winging it” every desoldering and soldering of components!

What your thoughts about on the AD8620??? Is it a good idea to put it in lpf??? or can you recommend a sop8 Dual channel op amp for limited spacing?! 

Don’t laugh but got a “electronics for dummies” book to read later as well. Lol.


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## raoultrifan

HeyManslowdown97 said:


> What your thoughts about on the AD8620??? Is it a good idea to put it in lpf???


Yes, why not? As long as it's not oscillating I don't see any issue.

Worth mentioning that AD797 (single) and the newer OPA1612 (dual) are extremely low-noise opamps and for high-gain stages (like voltage amplification) might really worth a try. Also, the I/V stage could be tested as well.


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## HeyManslowdown97 (Apr 9, 2019)

raoultrifan said:


> Yes, why not? As long as it's not oscillating I don't see any issue.
> 
> Worth mentioning that AD797 (single) and the newer OPA1612 (dual) are extremely low-noise opamps and for high-gain stages (like voltage amplification) might really worth a try. Also, the I/V stage could be tested as well.



I have heard nothing but good things about Opa1612 and I didn’t know they upgraded it.

Really like the Opa2192. It’s just a nice overall op amp for the price (IMO).

So what you are saying is oscillating as that’s what the clock is for?? So it isn’t a good idea for the lpf to have any CMOS op amp in the the early stages? 

I’d love to put the AD797 in the lpf if I could figure out a way!!!


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## raoultrifan

By newer I meant...newer, because OPA1612 is a newer design then let's say NE5532 or even LM4562. OPA1612 is one the most low-noise opamps ever built, so totally recommended for unity-gain stages (LPF or output stage of a DAC, but also I/V stage too).

You should be able to find single-to-dual DIP8 adapters for mounting 2xAD797 on a DIP8 socket.


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## HeyManslowdown97 (Apr 10, 2019)

raoultrifan said:


> By newer I meant...newer, because OPA1612 is a newer design then let's say NE5532 or even LM4562. OPA1612 is one the most low-noise opamps ever built, so totally recommended for unity-gain stages (LPF or output stage of a DAC, but also I/V stage too).
> 
> You should be able to find single-to-dual DIP8 adapters for mounting 2xAD797 on a DIP8 socket.



In your experience with the Opa1612 how stable is it with high frequency application in a DAC that tends to run sharp in the tremble? I.e. DSD DAC

I also need to use Low impedence caps with high current ripple as what the DAC calls for. You have any recommendations in the 500mA range Low Impedance Cap to power the opa1612 at 3.6mA per channel (chip) and beyond?!

Will try to fit adapters if I can use the AD797 as well! thanks for rec’s!

It does sound like the Opa1612 is ideal for what I need it for! I can always add the AD797 in the output stage


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## Rroff (Apr 10, 2019)

I've never had any problems with the OPA1612 and stability personally in a variety of uses the only exception to that I had a loose connection once in an amp from plugging in and out dozens of opamps for testing (not the last time it has happened either :| ) and had an OPA1612 get very very hot and start misbehaving - though it survived.


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## HeyManslowdown97 (Apr 10, 2019)

Rroff said:


> I've never had any problems with the OPA1612 and stability personally in a variety of uses the only exception to that I had a loose connection once in an amp from plugging in and out dozens of opamps for testing (not the last time it has happened either :| ) and had an OPA1612 get very very hot and start misbehaving - though it survived.




I have interested in low ESR Electrolytic Capacitors to power the Opa1612. My main attraction to them is a higher ripple current in the AC to “ power” the board onward as the opa1612 only requires low quiescent current of 3.6 mA but I know I’m in the Op amp thread so I don’t want to take the thread off topic. I just wanna know how much caps play a role on the op amp and what’s a recommendation for low impedance headphones combo with op amp and caps in a lpf in a DSD DAC. Or can someone guide to a head fi thread devoted to caps discussions if it exists to broaden my knowledge of them and how they used in applications!

My main objective is get more volume from the DAC not more gain since more gain creates more noise (if that makes sense).

Simply looking at the specs the opa1612 is pretty nice but I’ve yet to commit to a dedicated listening test.


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## carlmart

If you want to get more volume, but do no want to increase the gain, then you will to increase the power supply voltage. Or add another stage.


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## raoultrifan

https://www.analog.com/media/en/training-seminars/tutorials/MT-101.pdf worth a read. Usually, a fast multilayer 0.01-0.1uF + 1uF tantalum should do, but one 10...100nF in parallel with 10...100uF for each rail should do as well. This should ensure a good and oscillation-free operation for most opamps; of course, a crappy PSU and badly designed PCB will need additional care (I mean more caps across the rails, in between the opamp and the PSU itself). 

Not sure how to achieve a higher volume to an amplifier without increasing the gain. Also, I'm not sure why do you refer to a DAC instead of an amplifier? For a DAC, just find one able to output 4V RMS (ES9018 and I guess ES9038 chips can be programmed this way); at leas Burson Play can output > 4V RMS single-ended directly from the ES9018K2M chip, so the amplifier's gain is a bit over 2X (it outputs 10V RMS in the end).


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## HeyManslowdown97 (Apr 11, 2019)

carlmart said:


> If you want to get more volume, but do no want to increase the gain, then you will to increase the power supply voltage. Or add another stage.



Thanks for the suggestion. How do you add another stage??! I am interested in knowing how! I am thinking of using a step up converter but am afraid of frying the line that goes to the semiconductor (Ak4497eq) that’s datasheet voltage is set at up to 3.6v and I want to go up to 5v. The step ups LDOs are only good at low leaps in power supply.

The signal relay is 3VDC which I changed from the stock for better quality (coil, construction, etc), I thought about going up to 5, 6 or 9VDC but I’m afraid of frying the board because I don’t know how to overhaul the entire DAC’s power supply. Haha

What is interesting is that the new Ak4499 chip runs on current rather than voltage so that’s where I got the idea of increasing the current ripple but that might create more noise??!

All this stuff is interesting but just when you think you have a “figured it all out” and aha moment when you do more research you realize everything you first thought was brilliant becomes a huge miscalculation!

@raoultrifan your post never disappoint! Will study your info, thanks!!! I just meant overall volume without distorting and it would be nice to “power” your music via the amps in terms of sound would be great so I get what you meant about amp not the DAC; I was just thinking holistically 

Tantalum Polymer caps are interesting and it funny you mention them because I was reading up on them and was considering using them. They are really resistant to shock and vibration and a low ESR which sounds fascinating! I’m also considering Ceramic Caps for longer life  expectancy and I’ve heard they are really great with noise reduction along the the op amp.

The trick I believe is allowing the Op Amp to do it’s thing without the DAC getting in it way. The Burson as you described it sounds pretty bada**!


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## carlmart

Any direct changes on the Topping, except if you really know what your are doing and have DIY experience with SMD parts, is not recommended. 

The most you could or should do is soldering two three thin wires to L and R DAC output, and add another power supply and amplifier circuit OUTSIDE the Topping, on an external box. 

As the DAC output is balanced, just twisting each wire group will preserve the signal from noise and RFI. 

But a much simpler way would be to add an external headphone amp.


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## HeyManslowdown97 (Apr 11, 2019)

carlmart said:


> Any direct changes on the Topping, except if you really know what your are doing and have DIY experience with SMD parts, is not recommended.
> 
> The most you could or should do is soldering two three thin wires to L and R DAC output, and add another power supply and amplifier circuit OUTSIDE the Topping, on an external box.
> 
> ...



External headphone amp are really excellent choice provided that it’s a better sounding than you preamp and has a great battery life.

You solder three wire for per channel with a ground, positive and negative. 

(I know any mod has high risk and high reward)

Was thinking of rocking one of this but don’t know to connect it to the DAC.

US $1.23  11％ Off | Dual OP Amp Board Preamp DC Amplification PCB DC Pre-Amp Amplifier Empty Board Module for NE5532 OPA2134 OPA2604 AD826
https://s.click.aliexpress.com/e/iuDJYIk


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## carlmart (Apr 11, 2019)

Did I say battery powered headphone amp? I didn't, and certainly wouldn't recommend it.

A single DIP IC won't be able to provide high amplification for headphones.

You should look for designs where the chips can output high current or that use push pull output transistors, preferably mid power types.

And supply should be splitted and well regulated, more than +/-12v. Linear if possible.


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## Rroff (Apr 12, 2019)

raoultrifan said:


> Not sure how to achieve a higher volume to an amplifier without increasing the gain. Also, I'm not sure why do you refer to a DAC instead of an amplifier? For a DAC, just find one able to output 4V RMS (ES9018 and I guess ES9038 chips can be programmed this way); at leas Burson Play can output > 4V RMS single-ended directly from the ES9018K2M chip, so the amplifier's gain is a bit over 2X (it outputs 10V RMS in the end).



Yeah as far as my knowledge goes if you want more volume minimising gain you HAVE to have higher output voltage from the source (DAC) but that does mean having higher voltage on the amp side so you can avoid clipping, etc. at a given gain.

+/-12V rails (and whatever VRMS that is) is where most headphones stop gaining from higher voltage really and in many cases anything from +/-9V upwards is fine potentially a lot of headphones can be damaged if you go much over around 7-8 VRMS anyhow (usually a power rating but it often works out around that).

As a general point as well while having low impedance is important - going all out for ultra low impedance can actually be detrimental - there is usually a window of impedance that will get the best performance and stability from an amplifier especially some regulators can be very sensitive to ESR - hence why many amps have a pair of 220uf reservoir caps that you can't just randomly increase the size of and necessarily get good results despite a popular thing being replacing them with ~680uf caps.


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## HeyManslowdown97 (Apr 12, 2019)

> Yeah as far as my knowledge goes if you want more volume minimising gain you HAVE to have higher output voltage from the source (DAC) but that does mean having higher voltage on the amp side so you can avoid clipping, etc. at a given gain.



Yep, so many people don’t “hear” digital clipping. Voltage is the way to go 99% of the time! Although some DACs are now using replace higher voltages for higher current which is something that was considered taboo years ago but I think technology has gotten so good that you don’t even notice “drops” in AC.

AC also has major advantages mainly being safer in the board but I would imagine it being more sensitive.

The great boards have a balanced combo of both AC and DC especially in Op amps. (IMO).



> As a general point as well while having low impedance is important - going all out for ultra low impedance can actually be detrimental - there is usually a window of impedance that will get the best performance and stability from an amplifier especially some regulators can be very sensitive to ESR - hence why many amps have a pair of 220uf reservoir caps that you can't just randomly increase the size of and necessarily get good results despite a popular thing being replacing them with ~680uf caps.



Yea, there’s no way to know unless you A/B test and experiment. But based on what you wrote I have read very similar stuff. So it’s a balance. I can speak for experience increasing the uf’s in the caps doesn’t make it sound better but when you start off it just seems “logical” to do. It’s “sounds” great in theory until you listen and realize how wrong you actually were!


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## Spektykles

After some hunting time I found a supplier still have some AD797 Mil'spec NOS, they still have about 200 units in stock. I already ordered 2 pair just for fun. If anyone is interested then PM me, i could arrange some for you.


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## HeyManslowdown97 (Apr 16, 2019)

Spektykles said:


> After some hunting time I found a supplier still have some AD797 Mil'spec NOS, they still have about 200 units in stock. I already ordered 2 pair just for fun. If anyone is interested then PM me, i could arrange some for you.



There’s are actually quite a lot of resellers in the States that do this! Hong Kong is interesting since it’s only 30 minute boat ride to shenzhen yet it’s still unofficially run by the UK so they benefit from these ”specials”

Hong Kong is also home of the free internet to mainland china. It's how they allow protection for free speech.

AD797 spec ”bump” isn't that high for the military grade since the innovation is about 30 years old.

The AD797 was a response to the popular Opa627. So putting a military grade with slightly bump in specs at the time used for military purposes and now discontinued and decreases its supply while Increasing it’s demand value.

There’s is also Moore’s Law that makes Op amps transistor much better than they were 30 years ago.

Scarcity is used as commodity when demand is up and supply is down especially when parts of the world is closed to particular markets because of things like sanctions, etc*

All things equal you would still need a superior DAC with exact  equilibrium to perhaps notice any audible difference from the prosumer grade made today. Then there’s the quality of the recording and also what type of genre of music that will  emphasize certain features of the AD797 (military grade?!) that weren’t designed for music.

“Military grade” may be a detriment as an “Audio grade” as the application isn’t in lock-step with its functionality. Then there’s subjectivity in the form of the placebo effect of justifiability to one’s purchase.

There is more than just datasheet specs in the nuance of making and reproducing sound unless you talking about a  specific usage in music reproduction such a well temper piano, etc with exact specifications in the form of tonality and pitch. 

There’s just so many variables. It’s not about what is says in the requirement usages. Although such guidelines must be respected for they may cause damaged to any DAC or parts on the DAC.

But I am sure it’s worth a try for fun. Wouldn’t hurt to do so!

*


Spoiler



*“Scarcity


*


Spoiler



Principle. In *economics*, market equilibrium is achieved when supply equals demand. ... Disequilibrium also occurs when demand for a commodity is higher than the supply of that commodity, leading to *scarcity* and, thus, higher prices for that product.”[\Spoiler]


----------



## Ivan TT

Hi all!

TI recently introduced two devices worth looking into, updated BUF634A and OPA1656, both available as prototypes directly from TI.

New BUF634A has higher slew rate, wider BW and decreased quiescent current in wide-BW mode, and is cheaper than original 634 

OPA1656 is positioned for audio applications: low noise and really good THD (-131dB) and high output current (100mA), but still needs a series resistor to drive capacitive loads unfortunately.

Together will make a really good composite amplifier, I will try this application at some stage.


----------



## Themilkman46290

Ivan TT said:


> Hi all!
> 
> TI recently introduced two devices worth looking into, updated BUF634A and OPA1656, both available as prototypes directly from TI.
> 
> ...


So if my device had buf634 before, I could use these in its place?


----------



## Ivan TT (Apr 16, 2019)

Themilkman46290 said:


> So if my device had buf634 before, I could use these in its place?


Yes, although upgraded version may put extra demands on bypass caps and feedback loop components/values if used in composite device (such as your's AK4490 DSD).



Themilkman46290 said:


> So if my device had buf634 before, I could use these in its place?



At this stage it's not really known if higher specs are going to introduce any issues when used as a drop in replacement for old BUF634 in existing designs (most likely not) and I definitely did not try using it yet, so cannot guarantee it of course.

Maybe check if your circuit is similar to Figure 8 in datasheet (notice optional C1 cap, from what I remember it's about 50pF, this may improve stability with faster opamps if plan to try those. But something like OPA1642 would work fine and seems to be highly recommended for composite amp).

http://www.ti.com/lit/ds/symlink/buf634a.pdf


----------



## Ivan TT (Apr 16, 2019)

del


----------



## HeyManslowdown97 (Apr 17, 2019)

Themilkman46290 said:


> So if my device had buf634 before, I could use these in its place?



Yes it was designed to be a buffer so if TI ships to your country it’s worth a look especially if the BUF634 you are using is a fake.



Spoiler: The Why



It’s also worth noting that many who are misinformed don’t understand that the TI website is constantly being hacked (North Korea, Russia and Iran) so it’s not secure because the supply chain is located in the South China Seas which also is controlled internet-wise by China. The cable lines are underwater. The Chinese Government steals intellectual property and attempts to copy the technology to save on R & D and compete on the global markets flooding the markets with counterfeits causing lots of misinformation. (China’s ultimate goal is to control the Global Trading Routes)

The AK4490 is designed in both the United States as well in Japan. So if your DAC is made in China and not licensed then chances are you using fake components other than the Ak4490 chip itself. This is why US distributor like Arrow ask for documentation to sell in bulk or even to a civilian. The sanction is meant to put pressure on corrupt governments who hack elections! Ukraine is a buffer zone (pun unintended) where Russian operatives move freely back and forth and also hack their infrastructure constantly in Eastern Europe  (especially in Estonia where its a Digital Society (fascinating really!) and is literally were NATO Forces are looking at Russian Tanks). So if you live in this region it’s not that anyone is calling/accusing you of being a “terrorist” so it shouldn’t be taken personally! It’s too bad that there are nefarious actors poisoning expats in places like the UK but unfortunately this is the real threat not to mention that (52% of Russian wealth isn’t in Russia. It’s being used for money laundering, opening up shell companies and in Western Real Estate and manipulating liberal Democracy with Troll Armies.)



Moreover, you are not using BUF634 it for what’s is not designed for. A CMoy for instance which is designed to be used in a Headphone Amp isn’t designed to be used as a universal buffer but people do it.

However, a bump in specs with original parts can also make it sound far worse unless you have an authentic parts or you build it yourself with authentic parts.

Stability is a challenge. I once saw someone who followed all the resistor from a evaluation Board recommendation say it wasn’t stable in her DAC. it’s wise to KNOW beforehand rather than change something that may not work so you can save money.

This I also learned the hard way but I enjoy the the learning process as the materials were cheap and shipped overnight for free! 

(I have always wanted to try and change the +PPM on a DAC but don’t know if that would help the sound coming from the Op Amps, Crytek Oscillator, resistors, etc but that’s a complete overhaul and then you’d probably have to change the firmware!)

Maybe try asking someone that’s tried what you are doing and had success.

Also keep in mind that slew rate can also be harmful to sound used in audio. So specs alone sans anyway to measure the entire DAC holistically will drive you crazy when you start adding too many mods at a time. A few mods is better but still you don’t the relationship they have with other mods or what’s stock on the board.

“New BUF634A has higher slew rate, wider BW and decreased quiescent current in wide-BW mode, and is cheaper than original 634 “

It’s because it a prototype so it’s not in its final stage for mass production. It can also be give for free as a sample(s) on their website. 

Like Natural Selection, It’s a LOT of Trial and Error and tinkering and even when you get something to “work” as a “Proof of Concept” it still may not be the best configuration. This when trusting you ears becomes a valuable commodity (when used objectively.)And to be to fair some unorthodox mods just work when done even when 2+2=5. It’s perplexing and definitely a head scratcher to a logical thinker to say the least!

Extremely humbling modding especially when you think you figured it alllll out beforehand.


----------



## HeyManslowdown97 (Apr 17, 2019)

Yes it was designed to be a buffer so if TI ships to your country it’s worth a look!

Yes it was designed to be a buffer so if TI ships to your country it’s worth a look especially if the BUF634 you are using is a fake.



Spoiler: The Why



It’s also worth noting that many who are misinformed don’t understand that the TI website is constantly being hacked (North Korea, Russia and Iran) so it’s not secure because the supply chain is located in the South China Seas which also is controlled internet-wise by China. The cable lines are underwater. The Chinese Government steals intellectual property and attempts to copy the technology to save on R & D and compete on the global markets flooding the markets with counterfeits causing lots of misinformation. (China’s ultimate goal is to control the Global Trading Routes)

The AK4490 is designed in both the United States as well as in Japan. So if your DAC is made in China and not licensed then chances are you using fake components other than the Ak4490 chip itself. This is why US distributors like Arrow ask for documentation to sell in bulk or even to a civilian. The sanctions is meant to put pressure on corrupt governments who hack elections! Ukraine is a buffer zone (pun unintended) where Russian operatives move freely back and forth and also hack their infrastructure constantly in Eastern Europe  (especially in Estonia where its a Digital Society (fascinating really!) and is literally were NATO Forces are looking at Russian Tanks). So if you live in this region it’s not that anyone is calling/accusing you of being a “terrorist” so it shouldn’t be taken personally! It’s too bad that there are nefarious actors poisoning expats in places like the UK but unfortunately this is the real threat not to mention that (52% of Russian wealth isn’t in Russia. It’s being used for money laundering, opening up shell companies and in Western Real Estate and manipulating liberal Democracy with Troll Armies.)



Moreover, you are not using BUF634 it for what’s is not designed for. A CMoy for instance which is designed to be used in a Headphone Amp eval Board isn’t designed to be used as a universal buffer but people do it.

However, a bump in specs with original parts can also make it sound far worse unless you have an authentic parts or you build it yourself with authentic parts.

Stability is a challenge. And the though the new BUF634A has better specs it’s still a protocol and may not be in its final stage of production but TI does give it for free as a sample normally so it’s worth a look. However, 5 bucks plus 8-11 shipping bumps the cost per chip so it’s not practical maybe.

(I once saw someone who followed all the resistors based from a evaluation Board recommendations say it wasn’t stable in her DAC. it’s wise to KNOW beforehand rather than change something that may not work so you can save money.)

This I also learned the hard way but I enjoy the the learning process as the materials were cheap and shipped overnight for free! 

(I have always wanted to try and change the +PPM on a DAC but don’t know if that would help the sound coming from the Op Amps, Crytek Oscillator, resistors, etc but that’s a complete overhaul and then you’d probably have to change the firmware!)

Maybe try asking someone that’s tried what you are doing and had success.

Also keep in mind that slew rate can also be harmful to sound used in audio. So specs alone sans anyway to measure the entire DAC holistically will drive you crazy when you start adding too many mods at a time. A few mods is better but still you don’t the relationship they have with other mods or what’s stock on the board.

Like Natural Selection, It’s a LOT of Trial and Error and tinkering and even when you get something to “work” as a “Proof of Concept” it still may not be the best configuration. This when trusting you ears becomes a valuable commodity (when used objectively.)And to be to fair some unorthodox mods just work when done even when 2+2=5. It’s perplexing and definitely a head scratcher to a logical thinker to say the least!

Extremely humbling modding especially when you think you figured it alllll out beforehand.


----------



## Themilkman46290 (Apr 17, 2019)

Well guess I should wait on that, haven't messed with the ak4490 dsd yet, I would like to upgrade it but I am afraid I just don't know enough.

But the ak4490 drives my low impedance gear so much better then then ak4497 version, the latter being much better with me high impedance buds

For now I will just keep rolling amps in the lpf, until I get the balls to change out the opa275 and maybe the buf634
It would be nice to get a similar sound as my ak4497


----------



## HeyManslowdown97 (Apr 17, 2019)

“For now I will just keep rolling amps in the lpf, until I get the balls to change out the opa275 and maybe the buf634
It would be nice to get a similar sound as my ak4497”

Different circuitry per dac as well as firmware. For starters I don’t think Zishan Z3 does have a NOR Flash Drive Chip nor a Altera Max 2 and Stem motherboard which I believe are counterfeit as well.

However if you can clean up the PPM around the clock oscillator it would mostly like make it sound better! Also if you can get a crystek oscillator that fits inside the Zishan Z3 as well as correct specs to correspond with the firmware it will improve the clock so the op amps won’t oscillate as much?? Not sure. I think they call that “low jitter.” Not sure though. I haven't done any mods on mine yet. Some clocks are expensive and for good reason. In my view they are equally as important as op amps.



Spoiler



The biggest difference sound wise between the ak4497 and the ak4493 dacs is that the latter is less detailed but has more of bass-er sound with the sound being in the foreground.

Getting a Dual Ak4490 mono portable player DAC will bump the specs per channel dbs but they are around 300+ and probably sounds better than many Ak4497eq single chip dac when done correctly.

Dual Ak4497eq portable dacs cost about 1000+ and it’s only made by Ashton Kern as far as I know!

The Zishan is a bargain for a 100 bucks but not without major issues. Changing the  Diodes and Supply Relay (better coil conducting electricity) will do wonders to your DAC! These are very cheap mods. I also changed the Ss14 for the original Vishay ss14 in the analog board makes the firmware cook.

The BUF634 is a headphone driver and a current booster which is great provided you have no electrical problem to and from it. 

Now when I start up my Zishan it has a “voom” sound which is pleasant. However, it’s more conductive and sensitive to Electricity and any metal when it’s out in the open attracts  noise. It’s now very sensitive but sounds better! So any short or loose connection will create noise. It’s seems obvious but it’s much harder when it’s subtle and in the background and could be any loose connection that you made while modding. Sensitivity is awesome (if you can control it like gain!)

I am considering using a battery with more mahal like 3.7v 6000 or above! There really isn’t a considerable difference in size but would play a considerable roll with a battery powered DAC like the Zishan. (I’m thinking)



The problem with op amp rolling especially in the lpf is that you must KNOW how to reconfigure the resistors and caps and their relations to the rest of the series. As they are stock it runs a bit too sharp in the tremble and DSD is unforgiving in the high frequencies in terms of harshness. (Digital filters fro sigma delta software does wonders for this!) I would imagine putting an amp that’s bass-y would damp the high frequencies as well tinkering with the caps but it’s something you’d really need to know  how to calculate correctly. I’d like to lower the Ufs caps and used ceramic or tantalum in the entire board! But don’t know how to measure their value.

It’s frustrating because I know I’m not maximizing the sound of the op amps and don’t know how to reconfigure the resistors and caps on the board.

Tantalum caps are super reliable and long lasting however any bump in current or voltage and they are prone to damage.

(Top brands like Murata ceramic caps I’ve read reduce noise)

Or just put in a CMOY op amp in series board and make a parallel board and call it a day. Personally would rather make an external on made from an Altoid tin case.  Lol.



Spoiler: DIY Super CMoy 2x 9v Real Ground Headphone Amp



https://www.diyaudio.com/forums/hea...2x-9v-real-ground-headphone-relay-pcbs-4.html



There’s a dude from Germany who’s got his own website I found researching who made his own dual ak4497 DAC and I’ve been tempted to contact him for how he did it.

It’s a challenge and would take a lot of patients since you would have a lot of learning on the spot. However the benefits would be to an open source firmware and have the ability to program your own analog board is pretty rad and in laymen’s terms you know the entire process from top to bottom and would make the process easier moving forward to making your own s***!

Not to mention you learn valuable knowledge doing mods and messing up. The failure rate is extremely high but the mod bug is sooo damn addictive. It’s hard to  resist it’s Temptations for perfection. That probably doesn’t even exist but at least it  occupies the mind with problems within your control (unlike dealing with people). Lol.

DIYINHK has some nice diy dacs. Worth checking out their website. I have never used them but they seem pretty legit. Many HK Audio retailer are pretty legit with reliable parts or where they source them but you need to do your research.


----------



## carlmart (Apr 17, 2019)

Ivan TT said:


> Hi all!
> 
> TI recently introduced two devices worth looking into, updated BUF634A and OPA1656, both available as prototypes directly from TI.
> 
> ...



This is great news! Have a look at the OPA1656 application notes, as it shows an MM RIAA preamp and also a headphone amplifier, using exactly the BUF634 as driver. I don't see the series resistor you mention there. 

http://www.ti.com/lit/ds/symlink/opa1656.pdf

Unfortunately neither are available at Mouser yet, and nowadays it's not too easy to get samples from TI anymore or even possible.

For the bold DIYers, it would very easy to assemble the headphone preamp, using Pavel Macura's audio buffer, replacing the parts types according to TI's implementation.

http://pmacura.cz/buffer_en.html

http://pmacura.cz/pcb_buf.jpg

I think he still sells the pcb.

If you already have a similar preamp or headphone amp, you can simply replace the active parts. You would probably need an IC adapter for the OPA1656 though.

Let's hope we get LTSpice models for both chips soon, so I can simulate them.


----------



## carlmart

A very good news for someone who is looking for top notch headphone amp, probably enormously better than what you find around nowadays. 

Texas is selling what they call a BUF634ADEVMis an evaluation module. It costs very reasonable $99.

http://www.ti.com/tool/buf634adevm?jktype=tools_software

The only things you have to add is a box and a power supply, all available through eBay. 

You would need to drill the box to put the connectors through. You can also eliminate some of those connector which you don't need, that are meant for measurements. 

The module uses an OPA2810 as first stage, which is also a FET chip, also low noise and much faster than the OPA1656. 

The resulting head amp would be the equivalent to a several hundreds commercial product, with a top notch amplifier.


----------



## HeyManslowdown97

carlmart said:


> Texas is selling what they call a BUF634ADEVMis an evaluation module. It costs very reasonable $99.
> 
> http://www.ti.com/tool/buf634adevm?jktype=tools_software
> 
> ...



I saw the same evaluation board and mentioned it can be built as an external headphone amp as TI also puts up the schemes. (I mentioned this once and was ridiculed with  belligerent ad hominem attacks on a different thread by the same member) And you are right about the samples they are extremely frugal. 

Mouser will offer it soon but they sell it for to small manufacturers in bulk. The idea is that get in a commercial/semi commercial DAC/Headphone so they sell more of them. I believe this is set by TI not the redistributor. 

He wants to put it in an internal existing DAC (Zishan) He already did one with CMoy and got rid of the lpf in the DAC.  

Headphone amps don’t do anything to sound quality sound it will only amplify your music. So you would first have to like your DACs sound first. 

The buf634 is designed to be built as an external headphone amp


----------



## carlmart

I didn't read those critics anyone made to your suggestion to use that evaluation board. I wonder what they could criticize. 

Of course manufacturer or seller will or should give priority to manufacturers, In fact those parts are usually more reliable than the ones they sell to diyers. But that's the way it is. 

At least the parts you buy from Mouser or Digi-Key are legit, and usually good. 

Buying the evaluation board is a very good option. You should use a good quality power supply too. 

The screw-in connectors could all be eliminated, as well as the power supply jacks. So that would simplify the drilling and assembly on any metal case you could find. 

Of course a headphone shouldn't do anything to the sound quality, just amplify it to the levels the headphone needs. 

The quality is set by the DAC and the music source.


----------



## HeyManslowdown97

carlmart said:


> At least the parts you buy from Mouser or Digi-Key are legit, and usually good.
> 
> Buying the evaluation board is a very good option. You should use a good quality power supply too.
> 
> ...



The DAC In the thread was about the Zishan a Chinese-made DAC. The reason I purchased it and was/interesting in modding it because it has major electrical problems  with counterfeit parts. 

I am very frustrated with the fact that there are limits in choice in Dacs that don’t cost and arm and a leg for. 

The Zishan has the AK44*** series of semiconductor chips that sound amazing and also it’s DIY so you can mod it. 

The chip itself is what makes the sound on the DAC and everything else is crap on the player. 

Unfortunately, in the West patent laws and a  move away from audiophile portable players has cost them to become a niche market. 

Even the circuit boards are copyrighted and glued any change you make are against the law. 

That’s why I turned to the Chinese DAC. 

It’s funny you mentioned a great “Power Supply” because I wanted to change the Signal Relay for an authentic one and I got  scolded for that to as well I explained my +30 years in music production and that music production has improved and many recordings aren’t as great as you once remembered them with 2019 spec sheets. 

I have to honestly say this for me is still hard to get over. Better quality op amps for example the music sounds less “analog” but what I “like” about analog sounding is most likely distortion from the mediant that’s harness. 

We even got into the 30 year old+ argument about silver being “too bright” verses Copper as a conductor mythology. (All major and genuine parts uses some silver or silver alloy in their parts) 

Also many recording that used reel-to-reel in my opinion now uses way too much “airy” sound as they often recorded at a lower dbs  because of fear of clipping not to mention if there’s was ANY microphone that picked up semblance; it’s now picked up on the recording and amplified. Even the crappiest Artist has can make their music sound great with a great sound engineer.

Everyone has opinions (including myself) but I’m actually shocked by how people don’t change the beliefs even when new evidence contradicts their personal belief. 

Of course I make mistakes with my post and some post looking back I posted are cringeworthy based on what I thought with no experience. 

I just got started DIY-ing and unfortunately I ran into some people turbulence. It is refreshing to know that what I know to be true is echoed by more members on this thread! 

It’s fun to mod and learn about this stuff as a hobbyist. Generally, people are awesome in free sharing their experience. Often I have found the most kick butt DIYer is also the most patient, honest and modest. 

As s personal experience I find it gratifying to make something sound better and built up your self esteem with a sense of  accomplishment. 

My next project is to an evaluation board but first I’d like to fix this annoying “buzz” coming from my home speakers and perhaps put in a kick butt op amp I learned from this thread


----------



## Spektykles

Speaking of OPA1656, I just received sample of it and ready to replace my 3x OPA1652 in my portable amp. But honestly I wouldn't expect it to sounds outright better than 1652, it's already sound good.


----------



## carlmart

HeyManslowdown97 said:


> The DAC In the thread was about the Zishan a Chinese-made DAC. The reason I purchased it and was/interesting in modding it because it has major electrical problems  with counterfeit parts.
> 
> I am very frustrated with the fact that there are limits in choice in Dacs that don’t cost and arm and a leg for.
> 
> ...



What Zishan DAC is that you were or are involved with?

What change you make is against the law? You can change anything on something you own. 

Perhaps something you should consider is writing shorter texts and be more clear and what is you are attempting to do or plan to do.

I would like to help or comment on some things you said, as you already saw, but sometimes it's a bit difficult.


----------



## HeyManslowdown97 (Apr 17, 2019)

carlmart said:


> What Zishan DAC is that you were or are involved with?
> 
> What change you make is against the law? You can change anything on something you own.
> 
> ...



Don’t worry about it. I’m not asking you to get involved. It’s just refreshing was my main point.

You can’t change anything you want but risk losing warranties and you can’t just open an iPhone or a Sony Playstation and mod them.

The parts makers open source their chips because they encourage you to make stuff with them. However, even they license parts to major manufacturers and they take precedent over the civilian. So Sony May just make the part in house and avoid the licensing fee for instance. And of course lots of electronics companies have Government contracts with the Military.

They don’t care about the niche diy market as it’s not a major competition or huge money maker (until it is).

In America especially everything is litigation and the more representation the better chances to influence laws and lawmaking.

But this is very off topic and with respect to others’ it’s best to not discuss this on the op amp thread. Just brought it up because of why I chose to buy a particular dac. And because I’m “frugal”... well cheap. 

https://medium.com/u-s-pirg/how-big-tech-stopped-right-to-repair-in-new-york-9109a7565596


----------



## HeyManslowdown97

Hey has anyone tried the ADA4625? 

https://www.analog.com/en/products/ada4625-1.html


----------



## carlmart

What Zishan DAC did you try? 

I have seen the Z3, but it's not really a DAC, but a DSD and other formats card player. 

It also seems prepared for headphone use, not to feed a preamp or amplifier. 

Are there any other models?


----------



## HeyManslowdown97 (Apr 18, 2019)

carlmart said:


> What Zishan DAC did you try?
> 
> I have seen the Z3, but it's not really a DAC, but a DSD and other formats card player.
> 
> ...



I got the Zishan Z3 but I also got the dsd ak4497 which is a series dac is more complicated with a lpf.

Yes the Z3 is more or less a headphone amp and in many ways: less is more. The Ak4497 sounds more detailed but it’s bit trembly. The Z3 modded Up sounds great for bassy stuff with more oomph! I prefer the ak4497 but not by much! The pcb board is also better quality on the z3 (by a long shot!)

Funny you addressed me. Just did some really cool mods to my Z3.

Very cheap mod opens up the sound up a lot on the Z3.

These go where it’s labelled “SS14” (1)

https://www.arrow.com/en/products/ss14-e35at/vishay

These are labeled “K14” (4)

https://www.arrow.com/en/products/b140hwq-7/diodes-incorporated

And finally replace the LDO for 3.3 (1)

LP5907 3.3v (make sure it’s 3.3v, not sure if the 5v works?!)

Arrow, IMO is better overnight shipping (US) and free shipping. LDO is back-stocked so you can get it at Mouser or Digi-Key

https://www.mouser.com/ProductDetail/Texas-Instruments/LP5907MFX-33-NOPB?qs=biyDIajrTn6NhrJCoL/dSQ==

I ordered an oscillator today will let you know if it improves the sound even more and OPA1652AIDR that I've heard good things about on this thread.

If want to try one. I start with the Z3 but make sure its with the ak4493 not ak4493. Slightly better specs. 

It's dirt cheap (44-53 bucks US)


----------



## carlmart

Have you compared the Z3 with any of the Toppings?

Have you got a schematic or pcb photos?

Is the internal supply linear or switching? 

Which are the output chips?


----------



## HeyManslowdown97 (Apr 19, 2019)

carlmart said:


> Have you compared the Z3 with any of the Toppings?
> 
> Have you got a schematic or pcb photos?
> 
> ...



I’d be glad to show you some pics and you can see for yourself (I’d rather show and not confuse me with my description) but I’ll PM to you when I get a chance. (It’s 4:30 in the morning in NYC & I’m an insomniac)

I also picked up Zishan dsd ak4495SEQ last night which looks like it has the best schematics especially with more options for op amp rolling for $110 (Reg 114 but had a coupon for a 4 bucks off  ). And to me it looks like a DAC with op amps + a headphone amp baked into the scheme 2x BUF634 (but they are fakes that will be replaced with the newly BUF634A)

 I can show you pics of it but I don’t physically have one. However there are plenty of them online I can find (same with Z3 which I do have!)

Speaking of Opa amp which I really like the Opa828! It’s just consistent and boring for most but I love it!

It’s like lightweight champ like Mayweather and not a Muhammad Ali or (keeping it musical) a Hank Mobley and not a John Coltrane.

@raoultrifan Dude I gonna pick up the Opa1612 next purchase but the OPA1652AIDR was 2 bucks cheaper and well let’s not be pc...I’m cheap  haha


----------



## carlmart

Do go to sleep. Here in Brazil is now 6.00 AM, we are two hours ahead of NY. 

But I was looking at this photo of I don't know which Zishan:

https://www.head-fi.org/threads/the-zishan-dsds-corner.826185/page-17

With this Zishan ak4495SEQ prices are getting too close to Topping's, and I don't think they can improve on them. 

Tomorrow we go on.


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## yurt28 (Apr 19, 2019)

HeyManslowdown97 said:


> It’s funny you mentioned the high quality transistors as I always bring up Moore’s Law with many audiophiles and they don’t get the principle behind microprocessing and WHY it’s hard to replicate original chips without a huge budget and why patent laws to protect them from foreign jurisdictions that don’t follow international IP Laws like China is important for quality control and things like National Security.
> 
> (It’s because of this that I can really appreciate how in-depth your review is in regards to Bursons SS with magnified pics to illustrate their quality )
> 
> ...


Well explained you are defentely right about these transistors in this stuff. Its funny how some dacs sound different than the other ones even though the model could be the same???  Im using EsK2m right now and man they reisisted out the internels so we'll i am just amazed for how large it sounds for being such a tiny dac. Really amazing.


----------



## HeyManslowdown97 (Apr 19, 2019)

carlmart said:


> Do go to sleep. Here in Brazil is now 6.00 AM, we are two hours ahead of NY.
> 
> But I was looking at this photo of I don't know which Zishan:
> 
> ...



It’s depends... Topping have some nice Headphone amps and computer dacs.

I have the D10 and love it! With a PC/Mac there’s certainly more options. I really LOVE Synalyst HQplayer and as far I’m concerned it’s THE best software I’ve ever used for audio. It converts upsampling, has amazing digital filters. https://www.signalyst.com/

I have a Dual Ak4497eq balanced dac that I run through it and it’s amazing when I’m at home!  

The Zishan is more on-the-go.

I can confirm that Opa1652 is pretty good to drive headphones through. I would imagine the OPA1656 being slightly better depending with what it is matched with!


----------



## carlmart

I do not listen to headphones anymore. I had my share when I was a film & video professional sound recordist, and it was enough. 

Nothing compares to listening to good loudspeakers on a good acoustics room. So I really do not care for headphone amps. Only line amp level DACs. 

Try the Topping D50, which does use the OPA1612 at the output. The OPA1652 and OPA1656 seem quite similar. 

I wonder if there is a single OPA1656, and which name it is.


----------



## endia (Apr 19, 2019)

carlmart said:


> The OPA1652 and OPA1656 seem quite similar.



major differences are much lower noise (cmrr: 136 vs 110) and more importantly much higher output current (100mA vs 50mA) on opa1656.. it also has higher slew rate and gain bandwidth make sense depends on the application.


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## HeyManslowdown97 (Apr 19, 2019)

carlmart said:


> I do not listen to headphones anymore. I had my share when I was a film & video professional sound recordist, and it was enough.
> 
> Nothing compares to listening to good loudspeakers on a good acoustics room. So I really do not care for headphone amps. Only line amp level DACs.
> 
> ...



I totally agree with you. It’s nice for headphone which is very “Amplified”. I am not much of a specs guy (though they are important) and favor overall “sweet spot” listening for hours!

It’s good but hard to tame (in my opinion) and I don’t know how to calculate resistors/caps on a DAC to dampen them a bit. You hear more but it’s more fatiguing  which is counterproductive. The specs are a bit of an overload (in my opinion, my ears were ringing after one hour of listening) For me, listening to music that’s fatiguing starts to sound like white noise and isn’t really musical. But it’s great to turn up every now and then! Haha 

That said it’s innovative as op amps go and would work awesome for underpowered dacs and even external ones (I thinking). You hear the bump in current in volume. Crap it’s loud. Can’t even imagine how loud the opa1656 is!


----------



## NNewman

Hello. Does anybody have an experience with the discrete class D opamps?
Thinking if buying one...


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## HeyManslowdown97 (Apr 19, 2019)

NNewman said:


> Hello. Does anybody have an experience with the discrete class D opamps?
> Thinking if buying one...



It actually depends on what you are using them for?

I watched this last night out-of-the-Blue.

Traditionally Class D’s are great for lpfs in DCA since they are hybrid between Digital to analog. (If I remember correctly).

So I believe you’d have to give the thread what application you want to use the Class D for what purpose unless you figured that out already?!

Just putting this up here for educational purposes I don’t know what op amps this company makes nor endorse them but it makes it clear what Class(s) fall traditionally used for and what their characteristics are. It’s not a “rule” of them just a nice rule of thumb.


----------



## adeadcrab

carlmart said:


> Try the Topping D50, which does use the OPA1612 at the output. The OPA1652 and OPA1656 seem quite similar.
> 
> I wonder if there is a single OPA1656, and which name it is.



The Topping D50 is really quite good, there are 3 OPA1612 in the output stage, bass is slightly forward and detailed. Overall sound is great. Turned my electrostats into bass cannons!


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## HeyManslowdown97 (Apr 19, 2019)

Took screenshots from DIYaudio of posts of the description of what one of the engineers who worked on the team who designed the Opa1656 intentions were in creating it if anyone is interest in reading them.

Sadly TI cracked down on samples on personal email accounts because it didn’t result in more business.


----------



## carlmart

There's a thread on DIYaudio about the OPA1656, with a guy from TI telling very useful things. 

One thing is that TI is not sending samples when request comes from private mail services like gmail and similar. Only companies. 

He suggested to buy the parts direct from TI.


----------



## HeyManslowdown97 (Apr 19, 2019)

carlmart said:


> There's a thread on DIYaudio about the OPA1656, with a guy from TI telling very useful things.
> 
> One thing is that TI is not sending samples when request comes from private mail services like gmail and similar. Only companies.
> 
> He suggested to buy the parts direct from TI.



Marketing 101 by having one of the engineers  on the diy threads because it creates interest (especially from spec crazy diy-ers who “need” the lastest and best specs and use “word of mouth” via the audiophile threads to push cost up by popular demand) They do outsource them to official distributors ie Mouser, Digi-Key but you have to buy them in bulk (we’re talking 100s to 1000s) and you have to ”quote” this usually is dealt with by material managers.

Like I said previously the little guy isn't who they want unless he/she buys in bulk!

The shipping alone cost more than the opa amp!

You'll have to wait when its readily available or pay the shipping cost from TI which is double what the op amp cost is.This why they are profitable and stay in business 

However, Trump tariffs  from China cost companies million for cents on the dollar extra is past along the customer likely these chips will NEVER be made there because the Chinese steal the IP already unless its from Foxconn which is a Taiwanese company not Chinese.

Hong Kong is strategic in the region and despite pressure from BEIJING remains independent (somewhat). It’s trying to maintain its British rule but it’s getting harder and harder for them since it was given back to China back in 1999.

The big tech companies want it both ways. Google has its servers located in Hong Kong and claim they do serve mainland China that isn’t censored by the Chinese government (which is true) but they also have commercial interest in data mining as well. 

Lots of people don’t see the forest from the trees. There lots of gray areas my friend.


----------



## carlmart

Some info you said seems to be wrong. The price is $2.56 and you have to buy a minimum of 5. 

I doubt they will charge an expensive shipping, or even if they will charge one within the USA. They are interested that companies try their product, only they want to be sure who does. 

I can simulate ordering through my cousin's small company in California and see what happens. It's a small company that fulfills TI requirements, as it deals with electronics prototypes. 

As I we were thinking of prototyping a RIAA preamp, I'm interested. 

The only thing I learned yesterday is that the OPA1656 has a CMOS input, not JFET, as I would prefer it to have. It's fine for a headphone amp. but I'm not sure for a RIAA


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## HeyManslowdown97 (Apr 20, 2019)

carlmart said:


> Some info you said seems to be wrong. The price is $2.56 and you have to buy a minimum of 5.
> 
> I doubt they will charge an expensive shipping, or even if they will charge one within the USA. They are interested that companies try their product, only they want to be sure who does.
> 
> ...



I have ordered from them before. You don’t have to buy 5 of them nor be a company (although they ask for what purposes you using their products; it’s just a default setting. You can adjust the quantity (it’s just a bit tricky).

They may give you a discount since your cousin is a company NOT an individual (like aforementioned). Although, they wouldn’t ship something that’s national defense sensitive so in this case yes they want to know what you are using it for and registering it but for an op amp it’s not that sensitive. They do however  have it to comply with federal and state laws. Sadly though there are loopholes like establishing shell companies but the feds are cracking down on that especially after recent events in the states with foreign adversaries (and rightfully so).

They charge nearly 3 dollars per package because it’s package well. (Which is most likely well below what they ship for and what the shipping materials cost).

So when you do the math it cost them say 60 cents to produce one chip (that’s a modest figure) and you pay $2.56 that’s nearly 300% of what profit and is resulting in fixed price set by the board and if profits and units goes up as well as sales that is reflected in the stock prices but of course other factors go into stock price like product launches and supply chain issues, etc.

I’m ok with it. I’m just telling how to do the evaluation in terms of what the company is worth and how makes money. The choices is of course up to demand as it determines the supply.

For instance, Rio is the murder capital of the world someone is making money on the infiltrating guns into the black money because of demand. That’s why your president thinks its smart to give citizens the right to bear arms which is also a profitable market black or otherwise. (Take it from an American who deals with Mass Shooting every 6 months or so and Gun violence is one among the highest in the  industrialize nations: mo’ gun, mo’ problems and less safe because you are dealing with availability)

I prefer JFETs myself but the markets seems to pander to the portable market which is headphones and like I said I don’t like CMOS because of high gain and regardless how low the noise is you can still sense it in the frequencies but many headphone enthusiasts love that kind of power, volume and to power their low impedience headphones. The demand dictates the market not the other way around. Unless it’s a company like Apple which can be  didactical since isheep will buy their products regardless...


----------



## carlmart

According to the TI person collaborating in DIYAudio, not matter what it may bave been in the past, now TI ONLY sell to companies, quite likely based in the US. No exceptions for individuals. 

I remember, from the time manufacturers did send samples, that you had to declare several things. Then they stopped sending samples. 

In the case of Brazil it was because they sent it through couriers. Samples were then required to pay import taxes, but if they went through customs only. With courier companies they always take things through customs, so you are always required to pay taxes,

For a short time the manufacturers paid for the import taxes, and then they stopped. So no samples anymore. 

I'm not sure which is the sample policy within the USA with TI. Other companies, like THAT, do send free samples through their customer engineers. I don't imagine TI having that. They did in the past, but not now. 

The product price is what it is. You pay it or not. I think the AD745, recommended for RIAA preamps, is too expensive ($15) and I will not buy it. 

Our present president is a mad man. The guns laws he intents to pass will not get through, and he has already backed up about down. 

He doesn't know how to deal with Congress, and wishes the military dictatorship (which he claims it didn't exist) was still going and he was president, with no Congress. He forgets that being a captain, as he was before he was expelled, it would be likely to be elected president.   

Well, this is no place to speaks politics and we might get a warning. Let's stick to electronics.


----------



## HeyManslowdown97 (Apr 20, 2019)

carlmart said:


> According to the TI person collaborating in DIYAudio, not matter what it may bave been in the past, now TI ONLY sell to companies, quite likely based in the US. No exceptions for individuals.
> 
> I remember, from the time manufacturers did send samples, that you had to declare several things. Then they stopped sending samples.
> 
> ...



I feel you because I am cheap (haha) but out of Principles most times. Yea I always wonder why some amps cost so much and some not much.

15 is not bad if you only need say one but it can get pretty cost (especially if you don’t know if you’ll like it or a building on a budget).

(I just invested in a ultra low phase oscillator because it will clock better and sound better (which maybe wishful thinking on my part) they can be equally expensive as op amps)

They will sell it to individuals but you have to register. Just no more samples since it didn’t garner more business for TI (which is fair). They’d rather sell to companies since  if it’s “hit” in a commercial device it’s the first thing they will advertise as a “feature.”

I believe the Opa1656 are great and it’s not the much at 2.56 + shipping is STILL not a bad deal but I know it’s hard outside the US other than Europe, Australia and New Zealand

CMOS are innovative and as there is more detail with hardly any distortion but you have to Listen to them at a reasonable level because they are Extemely strong with powerful headphones and should have disclaimer but that’s not a problem you.

I don’t thinking using it in a RIAA will be bad it’s just that may not get the nuances it was designed for as a headphone amp.

The Opa1652 is pretty nice I’ve been listening to it for a day and half so I believe the Opa1656 may be worth it with minimal economic risk! With Powerful CMOS headphone op amps they are great, you just have to be careful not to crank it up for health reason and fatigue. 

Dude, it’s crazy town here (I’ll just leave it at that) Haha


----------



## raoultrifan

HeyManslowdown97 said:


> [...]
> @raoultrifan Dude I gonna pick up the Opa1612 next purchase but the OPA1652AIDR was 2 bucks cheaper and well let’s not be pc...I’m cheap  haha



I'm using OPA1652 in Matrix HPA-3B with great success, it's in Voltage-Amplification-Stage. The background noise is lower than MUSES01/02/8820/8920, LME49860 a.s.o. No overheating, no oscillations, voltage rails are +/-15V.

Sometimes I'm switching them both with BURSON SS V6 Classic duals, depending on my mood, although....without proper A/B testing I can't actually tell about the differences.

I do recommend OPA1652 in voltage gain stages!


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## HeyManslowdown97 (Apr 26, 2019)

raoultrifan said:


> I'm using OPA1652 in Matrix HPA-3B with great success, it's in Voltage-Amplification-Stage. The background noise is lower than MUSES01/02/8820/8920, LME49860 a.s.o. No overheating, no oscillations, voltage rails are +/-15V.
> 
> Sometimes I'm switching them both with BURSON SS V6 Classic duals, depending on my mood, although....without proper A/B testing I can't actually tell about the differences.
> 
> I do recommend OPA1652 in voltage gain stages!



I like it too! The funny thing about the Opa1652 is that it took a half day to really sound good, I'm not that much of a believer in the ”burn in” sounding better but I have found it takes time for newer components to be ”accepted” by a DAC to become an IC. (pun intended)  IMO anyway.

I've been told that switches aren't good for audio so the Opa1652 really makes up with voltage gain if there are flaws in the DAC. It's pretty impressive how some opa amps and other chips are made to ”make up” for poorly designed or ”shortcuts” by engineer to save space.

Ordered the opa1656 and the new BUF634A. They are both in ”Protocol” stage so I don't know how much along they are in final stage of release they will be when I get them but I'm fairy confident they are pretty close.

Updated: Just looked up the Matrix HPA-3B and it looks pretty rad. It's something I'd entertain getting in the future. Really love XLR balanced but never used them in headphones! Didn't even know they had a cable for them. Lol.

Updated Friday April 26, 2019:

Received both BUF634A & Opa1656 respectably Thurs and Fri. (Today) afternoon.

Both are great and aren’t the most aesthetically appealing for sound (which isn’t their main objectives and what makes them exceptional). 

The BUF634 is EXTREMELY Powerful and should only be used in buffering situations for headphone drivers or boosting current I would say in my opinions. It’s gotta be  great in the right situation, for me, just haven’t found it yet! 

The Opa1656 I received today is exceptional not something you wanna use as a “solo” act op amp but differently a must (imo) in a lpf or to drive headphones or even speakers (haven’t tried speakers yet to confirm though). Not the most characteristic op amp with “great” sound but it’s soundstage is dynamic and far reaching that WILL drive a more pleasant sounding “diva” star op amp like the usual suspects AD797 or the Opa627 or your favorite op amp to ecstasy in your ears reaching pure nirvana! 

It just brings out THE best in all your favorite sound op amps that you love while give them something extra while making up for their shortcomings.

It’s still early but I can safely say the opa1656 is a special one as far as THE ultimate utility “operational” amp that makes ANY great sounding op amp sound nearly blissfully perfect! 

It’s a bit trembly but not annoying just not as bassy sounding (which most of my music  pallet favors). I find most of TIs op amp especially Burr-Browns (which this is) are sound wise are balanced and neutral but great in my opinion.

Again not the “star” op amp that everyone goes crazy for but what makes the star op amp shine!


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## LaughMoreDaily (Apr 29, 2019)

My current favorite opamp: OPA1642. I took out the Audio Jade AD797BR from my Zishan Z1 because it's too dark. Would the AR sound brighter?

I thought I would love it... but nope. $30 gone.


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## HeyManslowdown97 (May 4, 2019)

LaughMoreDaily said:


> My current favorite opamp: OPA1642. I took out the Audio Jade AD797BR from my Zishan Z1 because it's too dark. Would the AR sound brighter?
> 
> I thought I would love it... but nope. $30 gone.



Yea- the Zishans Z1 & Z3 run a bit “dark” and bassy to begin with in my opinion.

The problem I believe is the clock frequency is set too low. 11.052 (always forget the exact number). You can toy with the resistors values to open up the sound but it may cause it to instability.

(I read that you can get the correct  resistance value by dividing the current and the voltage but you'll first need to measure it with an accurate multimeter to get the variables)

I haven't really played with the firmware but if it's not encrypted and with little bit of research you can recode the frequency to a higher frequency (its actually something ill experiment with at some point). It's gonna be a challenge but if you take calculated risk you'll no doubt learn valuable knowledge going through  process (this is how I've learned the most hardened and rewarding lessons)

Keep in mind your ”success rate” is not in your favor as a beginner but worth the journey!

The Opa1652 and Opa1656 sound fantastic in those zishans I had both as buffers and they really brought out the best in driving my favorite op amps. Currently rocking the BUF634AU in it.

I’d rec them to anyone rocking the z1!

Just got the Zishan ak4495 today and just in stock its THE best sound one, I’ve tried in the series!

I cant wait to get my hands in and mod!

The AD797BR by Analog Device is awesome it may have been wiser to have gone with the original not the Audio Jack??. you just have to find a killer DAC for it especially if you need more darkness (or cowbell).


----------



## LaughMoreDaily

HeyManslowdown97 said:


> The Opa1652 and Opa1656 sound fantastic in those zishans I had both as buffers and they really brought out the best in driving my favorite op amps. Currently rocking the BUF634AU in it. I’d rec them to anyone rocking the z1!


What do you mean by, used them as buffers? Is that the technical term for using them as sound chips in the device?


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## LaughMoreDaily

HeyManslowdown97 said:


> Just got the Zishan ak4495 today and just in stock its THE best sound one, I’ve tried in the series!


Youve heard every version of the Zishan DSD?


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## HeyManslowdown97 (May 6, 2019)

LaughMoreDaily said:


> Youve heard every version of the Zishan DSD?


 
Yes I now have both versions of Zishan “DSD” the Ak4497 and the ak4495. The latter is the older version of the two. Price wise they are relatively priced evenly the ak4495 is slightly more and in my opinion has a better circuit layout despite having the “inferior” chip.

The Ak4497 was the most up-to-date chip until this month when the Ak4499 dropped. (I’ll wait until they come out with a Zishan one).

The YUGE advantage of the Ak4499 vs the others’ is a. It’s runs on current not voltage which is interesting and not traditional b. It’s 4 channels not 2 channels which is pretty cool!

I’ll wait until more advanced modders sort out it’s kinks and it’s been on the market for awhile!

These chi-dacs have major electrical problems mainly because they have inferior counterfeit components relative to the Western genuine parts and markets but cost way less and aren’t “copyrighted”.

Really fun to learn on circuitry wise as an Intro to Basic dac making.

*To be honest I don’t know what it’s called I only referred to it as the “buffer” since the stock Z3 comes with a fake “Buf634”.

Essentially the Z1, Z3 are both Dacs and headphone amps all-in-one.

The buffer dual amps powers your opa1642 in the final stage.

(*Honestly I’m not the most über knowledgeable about the terminology (although it does help to use correct terms on threads so people know what you are talking about) but Ima relative beginner so I just give myself a lot of leeway (even when some snooty “expert” with more “experience” tries to give me crap about not knowing anything.)

The dual amp that drives your headphones is what you want to pair your opa1642 with the two op amps I aforementioned. However it’s gonna require soldering if you are comfortable with that there are other mods that can greatly improve your Zishan sound but require some experience with a hot air soldering rework station.

I just ordered the opa1612 to put in the lpf of my Zishan ak4497eq. Super stoked to put those bad boys in as I’ve heard nothing but great things about those op amps.

I’ll also add that all the op amps that I mentioned are wayyyy cheaper than the AD797 30 bucks so you can op amp roll and experiment with more variety to see if one fits your sound.

Most can be sourced at Arrow.com that’s located in the states so if you order before 5 PC coast time you’ll get it at your doorstep the very next morning in Canada fed ex ed. Not sure if that’s true for exports to Canada these days sadly with this useful idiot running the his show!


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## Spektykles (May 6, 2019)

Just finished some basic portable stuff with 3x P(rototype)-OPA1656 and 2x OPA1688 in parallel, wow 1656 heat up like hell compare to 1652 in this same system. still in burn in phase (yes a believer here  )


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## LaughMoreDaily (May 7, 2019)

HeyManslowdown97 said:


> I’ll also add that all the op amps that I mentioned are wayyyy cheaper than the AD797 30 bucks so you can op amp roll and experiment with more variety to see if one fits your sound.


I'm not a fan of the Audio Jade AD797BR it's not as clear as my 1622 but the mids are more forward and it's more musical than the 1622 but the blurry music is a downer.


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## HeyManslowdown97 (May 7, 2019)

LaughMoreDaily said:


> I'm not a fan of the Audio Jade AD797BR it's not as clear as my 1622 but the middle are more forward and it's more musical than the 1622 but the blurry music is a downer.



I hear you. Follow your sound and trust your ears there's no ”perfect” op amp just the perfect one(s) for you!

The 1622 is a nice all encompassing op amp. It gets a lot of nuance in your music. I like it as a headphone amp (as it was intended to be used). I have to be in the mood to crank it up but it gets distorted! For me, it’s not “distortion” like it sounds “bad” it’s just hits certain frequencies that makes my ears hurt from the sound pressure with fatigue that turns into “white noise” for me. (My ears are very sensitive to pressure and “blow” similar to crappy speakers, lol). The opa1622 is very powerful and some are generally attracted to it because of its outstanding benchmark spec sheet scores. The 1688 is very similar sounding I've heard but it's got the added advantage of being in soic package!

The opa1656 has what the 1622 has and then some (it’s VERY clear)! In my experience It's a little unstable because it’s still in protocol and I doubt nobody knows yet how to harness it proper yet but when it’s on, it’s amazing!

These days we are spoiled with so many choices and your sound should be personal so there’s no right answer.

You would love the Opa828 or the Opa827.

Both are really nice and exactly what you describe you’d like. You'll need two of them along with a adapter but they are pretty rad!


----------



## Mad Max

OPA827 is so damn nice.
Sounds more like an ADI chip than your typical BB, in ma 'pinion.


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## LaughMoreDaily (May 22, 2019)

I just got the ad8920 in the mail and it sounds nice. Some prefer it as a balanced output in the Zishan DSD but it sounds nice in a Walnut V2S too.


----------



## LaughMoreDaily

Has anyone compared the 1652 and 1662? Too many opamps... I heard the latter sounds cleaner?


----------



## Mad Max

1662 is a little different, has more of that "bipolar sound" a la ADA4898 or OPA1602. I suppose that it can sound cleaner depending on the circuit you put it into. It has a nice warm sound similar to 1652. In my tests so far, I tend to like it a bit more than 1652.


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## HeyManslowdown97 (May 28, 2019)

I've purchased the AD8620BR a couple of weeks back but haven't used it yet! If I do like it, I’d definitely like to get more of them for different DACs but the cost of the higher end AD8620BR is double that of its lower end ”AR” version.

I was curious if anyone has experienced the difference(s) sonically between the AD8620AR and the AD8620BR. The latter ”BR” is double the cost and I know it's baked in the datasheet the difference but am only concerned with the sound difference (if any?!)

Thanks


----------



## carlmart

Where are you going to use those AD8620?

Will it replace an SMD part that you will have to unsolder? Or will it need a DIP adapter?

My advice on replacing SMD opamps, particularly the smallest ones, is: don't do it. At least you are very experienced and have the right tools for doing so. 

The problem are not the chips you take out, but the very thin pcb tracks which can be damaged very easily, either with soldering out as when soldering in. 

Soldering out is the most risky part, I think, as you have to probably use unsoldering tape.


----------



## carlmart

My proposal for dealing with such mods is to design a small external pcb, perhaps using one that might exist (which I do not know about), fixed close to the circuit and preferably using some input resistors.

Space should be available for power supply bypassing, and there should be pads to connect the power supply directly to this small board.

In the past they called such boards "piggyback", but I do not know why.

Even if it's not usually recommended to use sockets, I would put sockets on such boards to be able to experiment with different opamps. For that you would also need existing DIP to SMD adapters.


----------



## carlmart

Perhaps this I'm talking about has already been proposed or used on some of the 440 pages this thread already has, If it has please write the post number of such proposals and mods. 

If the previous stage to the part we are going to swap is balanced, like on the Topping D-50 or most other DACs, then I would recommend to move that output out of the original box. 

Being balanced you would preserve noise and isolation, and you might use that external output on other units you might have now or in the future. 

You would also have space for a better power supply regulator. 

The main idea behind this is always to preserve the original pcb.


----------



## Mad Max

I just cut the legs off with my Xacto blade and then desoldering the legs is a breeze with no risk to the PCB.

Anyway, I've generally found that the ADI B grade chips sound better than the A grade equivalents.  Maybe they are better made somehow?  Who knows?


----------



## HeyManslowdown97 (Jun 1, 2019)

carlmart said:


> My proposal for dealing with such mods is to design a small external pcb, perhaps using one that might exist (which I do not know about), fixed close to the circuit and preferably using some input resistors.
> 
> Space should be available for power supply bypassing, and there should be pads to connect the power supply directly to this small board.
> 
> ...



I plan on soldering it to the dac not an adapter. It really a space problem. I really don’t wanna ticker with PCB boards with resistors since I don’t know how to fine tune the op amp yet. All I know as a rule of thumb all measurement must be equal.

One day if I get that far I’d like to develop my own daps and evaluation boards along with learn how to code them. There are two reasons for this: 1. A lack of them on the market that are designed for diyers due to a niche demand. 2. I would love to be able to program components to correspond  symbiotically with firmware I designed and have to sound awesome.

But that’s a lot of time and effort in the man cave with fits and starts.

Progression for me isn’t a linear line. I had a lot of beginners’ luck and learn the hard way that there’s more it than I thought! It’s very humbling with a lot of alone time to say the lest.

The forums help with brainstorming but even so you have to see what knowledge is useful to your design and priorities.

Also, a lot of the Diyers have different music Taste so what they vibe on my not necessarily be your thing.

There’s are a lot of bassheads out there. I’ve found especially in the headphone realm of audio. I like bass but it isn’t a main feature (unless it’s necessary in genre and track) to my music listening. I like balance with clarity sans nauseating tremble or overpowering bass with great dynamic range (like  crescendos, decrescendo, crossfades, nuance in quiet parts) with great music production value recordings.


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## CoiL (Jun 4, 2019)

CoiL said:


> Woah! Didn`t expect this out of OPA2228 used as HO opamp with Aune T1!
> Very organic, natural and open sounding! And seems to deliver quite good amount of details.
> Soundstage seems VERY open and airy but not sounding distant/laid-back with Siemens E88CC tube.
> Bass & percussion hits hard, tight and clean. Vocals/mids seem very natural. Guitars full and weighty.
> ...


Finally had time to solder ADA4084-2ARZ in DIP-8 to SOIC-8 converter PCB and installed it into my modded Aune T1.
Initial impressions after 10min listening - detailed, open and airy sounding (at times "holographic" but at same time with smidge of fowardness in vocals & instruments), well balanced sound, extended but not harsh/sibilant highs (cymbals and crashes sound very detailed and clear).
This is very good opamp and it might top even OPA1612A in this setup/gear but I`m suspecting OPA2228PA still sounds more organic and natural with great details all over spectrum, very open soundstage and tight textured bass.

Will report back after some "burn-in".

Current subjective preference in order (might change):

1) OPA2228PA
2) ADA4084-2ARZ / OPA1612AID (need to compare more)
3) NE5532A / NE5532PA
4) AD8599 (too bright/sibilant in this gear, otherwise detail-monster)

Edit: Did swap as fast as I could and OPA2228PA is just another level compared to ADA4084-2ARZ (at least in this hardware setup).
What I noticed was also slight upper-mid-bass/lower-mids "boom" with 4084 but know that I`m sensitive to any kind of mid-bass boost and prefer "dead-flat" mid-bass with rather slightly raised sub-bass and low extension (not bass-head). I mainly listen prog-rock-metal-jazz.
OPA2228 bass also hits harder and tighter and soundstage is "holographic" and very open/airy with more natural decays/reverbs.

Anyway, 4084 back to "oven" and lets hear if it changes better...

Edit: Hmmm... seems 4084-2 is humming very slightly when no music playing. Idk if it is occillating or I damaged it during soldering or just mismatch with this hardware but I better take it out for now and stay with OPA2228PA.

Edit2: LOL, I totally forgot about EMI/electronics nearby! Since my Aune T1 had open shell and my PC (sound source) was currently laying nearby "naked" without shell too, I was holding T1 too close to it and that`s where from that slight "hum" came. So, 4084-2 back to "burn-in".


----------



## Headmate

Hey all!

I need your suggestions. I'm modding my XD-05 which sounds too 'warm' or 'thick' for my preference.

Im trying to make it sound more spacious, detailed and transparent. Swapping out the stock OPA1612 SMD.

What are your suggestions for an *op-amp with spacious large soundstage, with good transparency & details*? must be available in SOIC8, dual channel.


----------



## Ivan TT (Jun 5, 2019)

Headmate said:


> Hey all!
> 
> I need your suggestions. I'm modding my XD-05 which sounds too 'warm' or 'thick' for my preference.
> 
> ...


AD8066 (wider soundstage)
AD8599 (more forward highs)
AD8620 (best transparency and details, most balanced of all)


----------



## CoiL

Ivan TT said:


> AD8066 (wider soundstage)
> AD8599 (more forward highs)
> AD8620 (best transparency and details, most balanced of all)


Pity I can try only AD8599 in my gear, would like to try those other two, especially AD8620 but it supports only max-dual power supply of 13V. Wonder if +-15V would kill it?


----------



## Ivan TT

CoiL said:


> Pity I can try only AD8599 in my gear, would like to try those other two, especially AD8620 but it supports only max-dual power supply of 13V. Wonder if +-15V would kill it?


It would.
Can you not bring rails down though?
Most DAPs use DC-to-DC boost converters that allow to set output voltage, so it’s pretty much 1 resistor replacement affair.


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## CoiL (Jun 5, 2019)

Ivan TT said:


> It would.
> Can you not bring rails down though?
> Most *DAP*s use DC-to-DC boost converters that allow to set output voltage, so it’s pretty much 1 resistor replacement affair.


I`m currently talking about my desk gear - Aune T1  It has separate +-15V power brick and uses no USB-power.
I haven`t messed with resistor or other opamp tweaking tricks as I haven`t put my time in it to learn about it.
You make it sound so easy  and if You say it is just one resistor-trick, I`m willing to give a try but need some guidance. I`m pretty skilled with soldering tiny stuff, so this is not problem.


----------



## Ivan TT

CoiL said:


> I`m currently talking about my desk gear - Aune T1  It has separate +-15V power brick and uses no USB-power.
> I haven`t messed with resistor or other opamp tweaking tricks as I haven`t put my time in it to learn about it.
> You make it sound so easy  and if You say it is just one resistor-trick, I`m willing to give a try but need some guidance. I`m pretty skilled with soldering tiny stuff, so this is not problem.


Ah, sorry, I believe power is arranged quite differently on this one compared to those DAPs and amps I had practical experience with.
Feel free to PM me photos of the main PCB under the amp PCB daughter board, we can try brainstorming it (to not to take this thread off-topic).
Or ask in the dedicated thread, I believe there’s one here and the may be some people with specific practical knowledge there too.


----------



## CoiL (Jun 5, 2019)

Ivan TT said:


> Ah, sorry, I believe power is arranged quite differently on this one compared to those DAPs and amps I had practical experience with.
> Feel free to PM me photos of the main PCB under the amp PCB daughter board, we can try brainstorming it (to not to take this thread off-topic).
> Or ask in the dedicated thread, I believe there’s one here and the may be some people with specific practical knowledge there too.


Will think about it as much as I know about Aune T1 thread - I think I`m actually first one to change its HO opamp and try out different ones (quinea pig)!



CoiL said:


> Finally had time to solder ADA4084-2ARZ in DIP-8 to SOIC-8 converter PCB and installed it into my modded Aune T1.
> Initial impressions after 10min listening - detailed, open and airy sounding (at times "holographic" but at same time with smidge of fowardness in vocals & instruments), well balanced sound, extended but not harsh/sibilant highs (cymbals and crashes sound very detailed and clear).
> This is very good opamp and it might top even OPA1612A in this setup/gear but I`m suspecting OPA2228PA still sounds more organic and natural with great details all over spectrum, very open soundstage and tight textured bass.
> 
> ...


Btw, did more listening and opamp lineup has changed for Aune T1:

*1) OPA2228PA *- most natural, organic, open, airy, balanced (think of Harman target), large soundstage & "holographic", layered, best imaging, sounding out of those.
It is just so coherent and revealing without being "hollow" or "details in Your face" (like AD8599).

*2) OPA1612AID* - well balanced but doesn`t sound so organic/natural and "misses something" that OPA2228PA has. Nothing bad, nothing really great - which makes it kind of "boring sounding". It just doesn`t grasp You into music like OPA2228PA.

*3) NE5532A / NE5532PA* - open/airy soundstage and pretty great imaging/layering but misses some mids timbre and bass/percussion tightness/thump (which sound laid-back sometimes). Very good opamp actually but some details/instruments may sound slightly "out of balanced/subdued".

*4) AD8599* - this is detail-monster like I said previously. Soundstage is very open/airy and bass/percussion is tight/punchy (beating 5322 & 1612) but highs can sound somewhat sibilant/harsh & "strident" depending on record/genre. I imagine if I had HPs with less highs/details and warm source - this opamp could do wonders.

*5) ADA4084-2ARZ* - first thing I notice with this opamp is slightly boosted mid-bass / low-mids "glare", which ruins overall "picture". I imagine this opamp would suit source gear with recessed mid-bass/low-mids as otherwise it sounds pretty good in other areas. In my rig - no go.

*X) Burson V5i-D* - did not work


----------



## Headmate

Ivan TT said:


> AD8066 (wider soundstage)
> AD8599 (more forward highs)
> AD8620 (best transparency and details, most balanced of all)




Thanks, Ivan! Have shortlisted the 8066.

Since OPA1612 has input upto 36V, AD8620 (13V) might be risky. Xduoo XD05 runs from 3.7V 4000mah battery.

How about LME49860MA or 49720MA? they are discontinued though. Any other opamps to consider? 

I really dislike colored/warm/bassy sound.


----------



## Ivan TT (Jun 5, 2019)

Headmate said:


> Xduoo XD05 runs from 3.7V 4000mah battery.


It has +/-9V rails (i believe), so most opamps should be fine.


Headmate said:


> How about LME49860MA or 49720MA?


It's pretty much the same opamp (different grades though), I never liked it as I find its highs a bit plasticy/artificial and soundstage lacking precision (even if appears to be wide), but obviously it's my subjective opinion/impressions.


Headmate said:


> Have shortlisted the 8066.


I'd say AD8620 is the most balanced/natural sounding (or less coloured one). It may come across as a bit boring initially, especially compared to somewhat more "vivid" opamps (I don't mean Bursons here, but there's few out there that act almost like exciters you can find in studios/DAWs).
By the way, if you can find values for C75 and C57 in feedback loop or C60-80 in LPF you can replace them with Panasonic PPS SMD caps, this should clean up highs a bit. But it has AK4490 and its highs are somewhat laid back and lacking resolution (compared to more recent or higher grade AKM DACs), unfortunately.


----------



## CoiL

Ivan TT said:


> Panasonic PPS SMD caps, this should clean up highs a bit.


Panasonic POSCAP`s are also very good for cleaning up power filtering and output/coupling/decoupling stages. At least I have very good results with those.


Headmate said:


> I really dislike colored/warm/bassy sound.


Maybe You should still also try out AD8599? Its pretty cheap to try out anyway. I`m suspecting it would be good option for You but since I haven`t tried other to, can`t give comparisons.


----------



## raoultrifan

Headmate said:


> [...]
> Since OPA1612 has input upto 36V, AD8620 (13V) might be risky.



AD8620 has actually 26V recommended voltage (+/-13V).

I find AD8599 very good in I/V, of course...OPA1612 too, but AD8620 very good in output buffer.


----------



## raoultrifan

CoiL said:


> Pity I can try only AD8599 in my gear, would like to try those other two, especially AD8620 but it supports only max-dual power supply of 13V. Wonder if +-15V would kill it?



I tried AD8620 at +/-15V for several minutes, but for a long term solution either you add in your circuit a pair of LM7812/7912, either you add 3 diodes per each rail (not quite the best design, of course).


----------



## HeyManslowdown97 (Jun 5, 2019)

I’ll ask this again since the discussion has turned into implementing AD8620 with resistor, etc

What is the difference between the AD8620AR vs AD8620BR besides the price tag sonically. Or is the difference felt in how it’s implementing into the DAC?  

There is a census forming in regards to it being the best output buffer op amp in that stage. That’s great to know since I have one just sitting here. Haha


----------



## Rroff (Jun 5, 2019)

raoultrifan said:


> I tried AD8620 at +/-15V for several minutes, but for a long term solution either you add in your circuit a pair of LM7812/7912, either you add 3 diodes per each rail (not quite the best design, of course).



I haven't tried it with the AD8620 but in my experience the AD8xxx series will get warm and die quite quickly much above their rated voltage - usually best results come at +/- 12V with them anyhow. Any attempt to drop voltage near the opamp is going to be extreme sub-optimal without some reasonable sized reservoir caps even with regulators that are stable without an output capacitor and a real risk of upsetting the rest of the circuit depending on how resilient the design used for generating a negative rail is against becoming unbalanced, etc.



CoiL said:


> *2) OPA1612AID* - well balanced but doesn`t sound so organic/natural and "misses something" that OPA2228PA has. Nothing bad, nothing really great - which makes it kind of "boring sounding". It just doesn`t grasp You into music like OPA2228PA.



The only opamp I've found that bridges the gap between the 2228 and the 1612 is the OPA2209 (think I got that right) which someone recommended here, sorry forgot who. But I still found I was missing something that the 2228 has.

I find myself coming back time and time again these days to a combination of OPA1692 (sadly not DIY friendly due to form factor) for buffers and either OPA2228 or AD8066 for the gain stage.


----------



## HeyManslowdown97 (Jun 5, 2019)

Rroff said:


> I haven't tried it with the AD8620 but in my experience the AD8xxx series will get warm and die quite quickly much above their rated voltage - usually best results come at +/- 12V with them anyhow. Any attempt to drop voltage near the opamp is going to be extreme sub-optimal without some reasonable sized reservoir caps even with regulators that are stable without an output capacitor and a real risk of upsetting the rest of the circuit depending on how resilient the design used for generating a negative rail is against becoming unbalanced, etc.



Educated guess but this would explain why the AD8620BR package cost 2x because of burnout. It must have an voltage regulator or resistance baked into the transistors or silicon chip!

Would also remark that I’m sure large manufacturers implementing the cheaper AD8620 chip know how prevent burnout via circuitry and moderating software to control its functionality which is again not privy to the Majority of Diyers.

This said, I’m am only speculating which is no different than one who quotes datasheets that are essentially guidelines and how they relate to a certain dap. My experience sometimes it works and other times like a heart transplant it rejects the implementation or works some of the time like I want it to.

The only true way to get optimum results is to create your own evaluation/development  boards and as bonus learn how to write code to get it to operate the way you want.

In many respects that’s why many manufacturers get away using cheaper costing op amps to lower overhead cost and get them to sound great even better when they are using top notch hardware implementations.

The biggest challenge even for them is to prevent background noise from the signal when using highly sensitive IEMs or truly balanced isolated mono channels. Based on my reading film caps work best to offset DC noise allowing the sound frequencies pass through the signal path to the output.

This is very challenging for DIYERS since we don’t have large budget to break crap in experiments like in a controlled laboratories. Unless of course you don’t mind pissing money away with experiment and parasitical living  vicariously through others mistakes on forums. But who among us would be brave enough to share such misdeeds to prevent property lost.


----------



## Rroff

One aspect that I've not cracked is the input side of a truly isolated dual mono output - bit beyond my expertise how to split the source ground without adding additional noise to the signal - isolated output is possible using transformers and/or DC-DC POL devices.

Unfortunately I don't have much input on the AD8620 as it is one of the opamps I've not spent a lot of time with.


----------



## CoiL (Jun 5, 2019)

Rroff said:


> The only opamp I've found that *bridges the gap between the 2228 and the 1612* is the OPA2209 (think I got that right) which someone recommended here, sorry forgot who. But I still found I was missing something that the 2228 has.
> I find myself coming back time and time again these days to a combination of OPA1692 (sadly not DIY friendly due to form factor) for buffers and either OPA2228 or AD8066 for the gain stage.


The thing is, I don`t need to "fill that gap" and seems I`m settled with OPA2228 @ gain stage 

Now I need to try out something instead OPA2134 as DAC differential opamp. Any recommendations what to pair with OPA2228 and is compatible at that stage? Not sure if OPA1692 fits there?


----------



## HeyManslowdown97

CoiL said:


> The thing is, I don`t need to "fill that gap" and seems I`m settled with OPA2228 @ gain stage
> 
> Now I need to try out something instead OPA2134 as DAC differential opamp. Any recommendations what to pair with OPA2228 and is compatible at that stage? Not sure if OPA1692 fits there?



What if you created more stages op amps  and increased the voltage or current so not lose power via creating custom circuitry. Wouldn’t it bridge gaps with the differentiations provided you prioritize the series in which the op amps in the sequence you like best?

Could be fun experiment!


----------



## Rroff

CoiL said:


> Now I need to try out something instead OPA2134 as DAC differential opamp. Any recommendations what to pair with OPA2228 and is compatible at that stage? Not sure if OPA1692 fits there?



Annoyingly in terms of performance it is hard to beat the LM4562 (or higher end LME variants) in that application especially as they aren't crazy expensive. The actually better options generally cost 20x more.


----------



## HeyManslowdown97 (Jun 5, 2019)

[/QUOTE]


CoiL said:


> Will think about
> 
> *1) OPA2228PA *- most natural, organic, open, airy, balanced (think of Harman target), large soundstage & "holographic", layered, best imaging, sounding out of those.
> It is just so coherent and revealing without being "hollow" or "details in Your face" (like AD8599).



Um based on this description of the Opa2228PA I’m salivating at the chance to my hands on this one!

In Estonia We Trust: A digital country with Arvo Pärt I’m sold on CoiL’s post!



Rroff said:


> Annoyingly in terms of performance it is hard to beat the LM4562 (or higher end LME variants) in that application especially as they aren't crazy expensive. The actually better options generally cost 20x more.



Wouldn’t exactly used the word “Annoyingly” when it’s a. Cheap and b. Hard to beat.


----------



## HeyManslowdown97

Edited: Merged Post.


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## CoiL (Jun 5, 2019)

HeyManslowdown97 said:


> Um based on this description of the Opa2228PA I’m salivating at the chance to my hands on this one!
> In Estonia We Trust: A digital country with Arvo Pärt I’m sold on CoiL’s post!


LOL, it depends on application and design/concept of PCB too! If it sounds great in my hardware, doesn`t mean it certainly sounds so in different gear. And let me remind You that Aune T1 DAC uses SS DAC + tube buffer (Siemens E88CC goldpin "holy grail of tubes") + SS amping. Also I have already done some mods to it. If You have only SS DAC/amp, Your result might be different.
Though, seems that what I was describing about those opamps I tried, matches general opinion about their sound.

Will do some spec research about LM4562 and see if I can order it from local electronics shop (I get all my opamps from there with trusted legit sourcing). So, You guys recommend to try it first instead OPA2134 DAC differential opamp?

Edit: Checked  and I can only get LM4562NA/NOPB in DIP-8 package. Is there SQ difference between LM4562*MA*?
Also, I have V5i-D free for using cuz it didn`t work @ HO - should I try it or is it only good for final output stage?
And unfortunately, OPA1692 is not available from that shop. Geesh, I need to order from Mouser? Don`t want to know how much is shipping cost.


----------



## HeyManslowdown97 (Jun 5, 2019)

CoiL said:


> LOL, it depends on application and design/concept of PCB too! If it sounds great in my hardware, doesn`t mean it certainly sounds so in different gear. And let me remind You that Aune T1 DAC uses SS DAC + tube buffer (Siemens E88CC goldpin "holy grail of tubes") + SS amping. Also I have already done some mods to it. If You have only SS DAC/amp, Your result might be different.
> Though, seems that what I was describing about those opamps I tried, matches general opinion about their sound.
> 
> Will do some spec research about LM4562 and see if I can order it from local electronics shop (I get all my opamps from there with trusted legit sourcing). So, You guys recommend to try it first instead OPA2134 DAC differential opamp?
> ...



Yep, I 100% agree about how the op amp is applied and in what DAC (the quality of circuitry and PCB board)

I highly recommend the opa1656 it’s really incredible despite being a prototype so you would have to order from TI itself. (In the states the shipping is 6.99 if you needed to compare pricing with mouser.)

One caveat though it’s just not natural sounding on its own. If you master it differentially with say the AD8620 or the Op2228PA the world is yours friend! 

****

Just got this new F.Audio FA2. It’s a portable music player with an AK4497 Chip.

First impression is that it plays pretty good in stock mode. Unlike Topping many Chi-Fi Shenzhen DIYERS using fake counterfeit inferior parts but it’s claims to have opa1642 and opa1612.

It’s got some major firmware issue playing .dff files (my favorite) that I’m hoping will be solved in updates so I cannot say that I can recommend it to anyone right now!

It would appear the firmware to be plagiarized by Fiios so I’m gonna try to put their firmware on SD and see if I can change it be more stable and fully functional (fingers crossed)

Here’s what the dac looks like inside I’d anyone here wants to make any suggestion as to what op amps they can recommend based on circuitry. (It’s the pic above- as you can see I’m not the savvy with Head-Fi posting Java)

I’ll also copy and paste what the claims are that is in this dac in the Spoiler (which again are most likely counterfeit).

Ugh, I wish Topping would come out with a portable music player their make nice desktop dacs diy that are friendly too! Love them.

Apologies in advance for posting something slightly off topic. I’ll be mindful of this in this thread to other users’ with open questions like mine. 

Side note: it’s hard remembering all these damn numbers used in op amps for me as  recommendations. lol. 



Spoiler: F.Audio Claim



What Problems FA2 Solve

*We know that the current output stage of a general amplifier consists of two amplification lines: one line handles the negative (negative half cycle) output signal, and the other tube processes the positive polarity (positive half cycle) output signal. This can minimize the quiescent current, but to drive 8~600 ohm headphones, it must have a large amplitude of voltage and current; there are 4 or 8 tube portable players on the market, but not working in Class A,There may be some distortion, called cross distortion. It appears at or near the zero crossing of the output signal. If the two branches of the circuit do not match exactly, crossover distortion often occurs;*



*FA2 completely solved the above two problems and shared the circuit architecture: the digital receiver of FA2 adopts AK4497EQ DAC Chip, IV - Ti(BB) OPA1632-Fully Differential I/O Audio Amplifierr; OP adopts OPA1612 (bipolar-input operational amplifiers-completely independent circuitry for lowest crosstalk and freedom from interactions between channels, even when overdriven or overloaded.), Toshiba 8-pair tube current amplification; among them, OP level (voltage, current amplification stage) adopts differential balanced output and works in Class A state; From DAC output to Toshiba 8-tube full direct coupling mode, ensuring high fidelity, High signal-to-noise ratio (FA1 signal-to-noise ratio (121db)), good dynamics without distortion; with good headphones, experience music playback in depth;

*


[\Spoiler]


----------



## Rroff (Jun 5, 2019)

CoiL said:


> LOL, it depends on application and design/concept of PCB too! If it sounds great in my hardware, doesn`t mean it certainly sounds so in different gear. And let me remind You that Aune T1 DAC uses SS DAC + tube buffer (Siemens E88CC goldpin "holy grail of tubes") + SS amping. Also I have already done some mods to it. If You have only SS DAC/amp, Your result might be different.
> Though, seems that what I was describing about those opamps I tried, matches general opinion about their sound.
> 
> Will do some spec research about LM4562 and see if I can order it from local electronics shop (I get all my opamps from there with trusted legit sourcing). So, You guys recommend to try it first instead OPA2134 DAC differential opamp?
> ...



For that application the LM4562 has a moderate advantage in terms of performance on paper - the reason I said annoyingly is that I tend to find the LM4562 introduces a bit of a clinical nature to the sound while the OPA2134 is warmer (which may or may not manifest depending on your design) but it is hard to beat it for performance.

I'm not aware of any differences sonically between the NA and MA.

The 1692 is only available in SSOP IIRC or atleast a similar very small form factor which makes it a pain to use for DIY - meaning it needs soldering to an adaptor and not just a regular SOIC->DIP one.


----------



## HeyManslowdown97

Rroff said:


> For that application the LM4562 has a moderate advantage in terms of performance on paper - the reason I said annoyingly is that I tend to find the LM4562 introduces a bit of a clinical nature to the sound while the OPA2134 is warmer (which may or may not manifest depending on your design) but it is hard to beat it for performance.
> 
> I'm not aware of any differences sonically between the NA and MA.
> 
> The 1692 is only available in SSOP IIRC or atleast a similar very small form factor which makes it a pain to use for DIY - meaning it needs soldering to an adaptor and not just a regular SOIC->DIP one.



Makes total sense about the “clinical nature” vs being “warmer” almost analogue in description sonically than what’s on paper. It’s for these reasons I could never get into the opa1622 despite its gloried spec sheet. I respect performance as an achievement just not my kind of sound so I get that frustration of wanting to ”beat” LM4562 in this competitive nature of spec sheets. The question should be asking for what it means as a placebo effect what if you just trusted your ears and then go to spec sheets later as a second impression (as a matter fact). 

If the 1692 package has been out for a while shouldn't be hard to find an adapter if you have space to put it into your rig?!


----------



## Rroff

HeyManslowdown97 said:


> If the 1692 package has been out for a while shouldn't be hard to find an adapter if you have space to put it into your rig?!



It isn't hard to find - but VSSOP is not DIY friendly unless you have a hot air station or a very steady hand. Looks like since I bought they've released an SOIC version however - showing up as a new product on mouser.


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## HeyManslowdown97 (Jun 5, 2019)

Rroff said:


> It isn't hard to find - but VSSOP is not DIY friendly unless you have a hot air station or a very steady hand. Looks like since I bought they've released an SOIC version however - showing up as a new product on mouser.



Arrow.com has it as well its free shipping  depending on where you live if they will ship it to you!

Any where near Russia is almost always a huge no, no even for Mouser from US distributors; it’s against the law! 

It's ”New” because it's in a SOIC package.

https://www.arrow.com/en/products/opa1692idgkr/texas-instruments


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## CoiL (Jun 6, 2019)

Rroff said:


> For that application the LM4562 has a moderate advantage in terms of performance on paper - the reason I said annoyingly is that I tend to find the LM4562 introduces a bit of a *clinical nature to the sound while the OPA2134 is warmer* (which may or may not manifest depending on your design) but it is hard to beat it for performance.


Clinical is what I do not want! But maybe paired with OPA2228 it is more "forgiving"?
Actually, when thinking about it, I do not wish to change current setup (OPA2134 + OPA2228) sound signature but want to test if SQ can be improved.



HeyManslowdown97 said:


> Arrow.com has it as well its free shipping  depending on where you live if they will ship it to you!
> *Anywhere near Russia is almost always a huge no*, no even for Mouser from US distributors; *it’s against the law!*


I live in Estonia which has border with Russia. Idk what the heck You are talking about as we don`t live in past anymore. Never had issue with Mouser (but shipping cost can be absurd sometimes).
Just paid & placed order for LM4562MAXNOPB and OPA1692IDR from Arrow for 3.93$ with free shipping!


----------



## Headmate

Guys,

TI has stopped production of LME49860 and LME49720?

and what's the difference between -MA & -MAX/NOPB?


----------



## Ivan TT

CoiL said:


> OPA1692


Try arrow.com they have free shipping, but only allow purchases from some countries.
It’s a bit tricky to solder due to form-factor and you need appropriate pcb adaptor (Apparently there’s SOIC8 out there too, nice! I had to solder MSOP, that was fun!). It has “in-house” BB sound, maybe a bit cleaner/less coloured version of 16x2 family.
Compared to 2228 it does not have “shimmer” if you know what I mean? but kind of moves it in midrange, not in as coloured way as older soundplus designs do, but still noticeable.


----------



## CoiL

Ivan TT said:


> Try arrow.com they have free shipping, but only allow purchases from some countries.
> It’s a bit tricky to solder due to form-factor and you need appropriate pcb adaptor (Apparently there’s SOIC8 out there too, nice! I had to solder MSOP, that was fun!). It has “in-house” BB sound, maybe a bit cleaner/less coloured version of 16x2 family.
> Compared to 2228 it does not have “shimmer” if you know what I mean? but kind of moves it in midrange, not in as coloured way as older soundplus designs do, but still noticeable.


Thanks for info. Will see if they ship to Estonia. Hope so. Otherwise have to wait for TME/Farnell stock.


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## HeyManslowdown97 (Jun 6, 2019)

I’ve noticed that you are fond of Siemens 88cc golf pin tube amps what’s the difference between solid state vs Tube? Not a lot of people use them anymore so I’m alway fascinating by those that still do!

Saw this PAG 2310 implemented in a design and was intrigued. It’s 16 pin volume control for op ams that can have software written for it. The dap had like 4 amps on it. This idea of being about to control volume on individual amps in a DAPs and software seems like a pipe dream. Wish I took a pic of it.



http://www.ti.com/lit/ds/symlink/pga2310.pdf


----------



## CoiL

HeyManslowdown97 said:


> I’ve noticed that you are fond of Siemens 88cc golf pin tube amps what’s the difference between solid state vs Tube? Not a lot of people use them anymore



It`s just the best tube I have and it is even called "holy grail" among 6922/E88CC/CCa tubes: https://www.tubemuseum.org/ProductDetails.asp?ProductCode=SH_E88CC-1965
I have 5 of them: https://cdn.head-fi.org/g/5690299_l.jpg You don`t want to know how much they actually cost now 
About difference between solid-state and tube, don`t know how to comment as my gear is tube buffered SS. I don`t have pure tube amp or dac utilizing their potential 100%.
Btw, lot of ppl in audiophile community use tubes.


----------



## Rroff

CoiL said:


> Clinical is what I do not want! But maybe paired with OPA2228 it is more "forgiving"?
> Actually, when thinking about it, I do not wish to change current setup (OPA2134 + OPA2228) sound signature but want to test if SQ can be improved.



Might be worth trying the 2227 in place of the 2134 - IMO it is basically an OPA213x with better sound quality, better bass and just generally more involved in the music than the 213x opamps - it is at best like a cousin to the 2228 though sonically IMO but probably not an issue in a differential stage.

Unfortunately it is probably a case of trying a few different opamps and see what works for you with the circuit you are using. You might be happy with the OPA1692 in that position as I found it a good combination with the OPA2209 (not tried with the 2228 yet).


----------



## raoultrifan

Headmate said:


> Guys,
> 
> TI has stopped production of LME49860 and LME49720?



No way, but what makes you think that?



Headmate said:


> and what's the difference between -MA & -MAX/NOPB?



Packaging only, SOIC vs. PDIP; have a look to the bottom of http://www.ti.com/lit/ds/symlink/lme49720.pdf.


----------



## CoiL (Jun 7, 2019)

Rroff said:


> Might be worth trying the 2227 in place of the 2134 - IMO it is basically an OPA213x with better sound quality, better bass and just generally more involved in the music than the 213x opamps - it is at best like a cousin to the 2228 though sonically IMO but probably not an issue in a differential stage.
> 
> Unfortunately it is probably a case of trying a few different opamps and see what works for you with the circuit you are using. You might be happy with the *OPA1692 in that position* as I found it a *good combination* with the OPA2209 (*not tried with the 2228 yet*).


Will take a look at OPA2227 specs and comments.

I already got recommendation to try out OPA1692 + OPA2228 by You in that place and it is already ordered&paid for.
I thought You already tried OPA1692 + OPA2228 ?


> I find myself coming back time and time again these days to a *combination of OPA1692* (sadly not DIY friendly due to form factor) for buffers and either *OPA2228* or AD8066 for the gain stage.





CoiL said:


> Just paid & placed order for LM4562MAXNOPB and OPA1692IDR from Arrow for 3.93$ with free shipping!


Order is confirmed and shipped out via DHL


----------



## Rroff (Jun 7, 2019)

CoiL said:


> I already got recommendation to try out OPA1692 + OPA2228 by You in that place and it is already ordered&paid for.
> I thought You already tried OPA1692 + OPA2228 ?



Not in the combination you are using it for - I've used the OPA1692 (paralleled) for buffers (final stage in a stand alone headphone amplifier) as it can do 50ma output without breaking a sweat but not as a differential stage off a DAC.

EDIT: I was assuming you were doing something like page 20 here http://www.ti.com/lit/ds/symlink/pcm1794.pdf with the OPA2228 in U1/2 and OPA2134 in U3 - I've mainly used the LM4562 in U3 position.


----------



## CoiL

CoiL said:


> rder is confirmed and shipped out via DHL


This is insane-fast shipping! O_o
3-4 days from Arrow US to Estonia (east EU border-country) and my LM4562MAXNOPB and OPA1692IDR are HERE! O_o 
Unfortunately I ran out of SOIC-8 to DIP-8 PCB converter boards, so it takes time for me to get those, solder chips and compare against eachother and with OPA2228.


----------



## HeyManslowdown97 (Jun 12, 2019)

CoiL said:


> This is insane-fast shipping! O_o
> 3-4 days from Arrow US to Estonia (east EU border-country) and my LM4562MAXNOPB and OPA1692IDR are HERE! O_o
> Unfortunately I ran out of SOIC-8 to DIP-8 PCB converter boards, so it takes time for me to get those, solder chips and compare against eachother and with OPA2228.



Sad News! Arrow.com no longer has free shipping under 50 dollars.  

Most likely has to do with “Tariffs”. Very simple solution a VAT at least that goes to the micro-economies! 

They are offering free overnight shipping for domestic over 50 bucks but will most likely pivoting to the very similar Digi-Key and Mouser type shipping and handling cost. 

“Free express shipping does not apply to purchases made on www.arrow.com/MyArrow nor purchases made on components.arrow.com. Orders under $50 USD will automatically have a handling fee of $12.99 USD applied to the order total. The $50 threshold is determined before taxes/fees and after any discounts are applied to the order.  Arrow reserves the right to end this promotion at any time without notice.”


----------



## CoiL

Well, that`s luck on my behalf and sorry for those who missed opportunity...


----------



## Headmate

*OPA827* vs *AD8065*

Which one might have a wider/bigger soundstage? and if anyone can point out the sonic differences between them?

Thanks!


----------



## Rroff

Headmate said:


> *OPA827* vs *AD8065*
> 
> Which one might have a wider/bigger soundstage? and if anyone can point out the sonic differences between them?
> 
> Thanks!



Don't have the experience with the 827 to comment on soundstage but the AD8065 doesn't have a particularly wide soundstage but it does articulate the soundstage well if that makes sense - for want of a better technical explanation it seems to preserve directional cues down to lower frequencies than other opamps do which gives it some decent bass and a good sense of positioning/separation. One of my favourites as it has decent mid-range detail as well somewhat unremarkable for treble I'd say at best it is inoffensive when it comes to higher frequencies. In some applications you might find upper mid-range sounds veiled but that can usually be improved by bridging it's power supply pins with a small capacitor* and for some reason almost entirely goes away in circuits that use some kind of active ground setup.

* Personally I use a 10uf Nichicon KZ electrolytic for this purpose but others swear by the use of a 0.1-0.22uf film cap there instead - I have no idea which is better from an engineering/accuracy standpoint but I know it sounds good to me.


----------



## Headmate

Rroff said:


> Don't have the experience with the 827 to comment on soundstage but the AD8065 doesn't have a particularly wide soundstage but it does articulate the soundstage well if that makes sense - for want of a better technical explanation it seems to preserve directional cues down to lower frequencies than other opamps do which gives it some decent bass and a good sense of positioning/separation. One of my favourites as it has decent mid-range detail as well somewhat unremarkable for treble I'd say at best it is inoffensive when it comes to higher frequencies. In some applications you might find upper mid-range sounds veiled but that can usually be improved by bridging it's power supply pins with a small capacitor* and for some reason almost entirely goes away in circuits that use some kind of active ground setup.
> 
> * Personally I use a 10uf Nichicon KZ electrolytic for this purpose but others swear by the use of a 0.1-0.22uf film cap there instead - I have no idea which is better from an engineering/accuracy standpoint but I know it sounds good to me.




Thanks mate, which dual channel opamp, SOIC8 might have a wide airy soundstage to offer?

I was unable to find LME series in SMD here. Have ordered AD8066 SOIC8.


----------



## HeyManslowdown97

Hey All- Gonna drop this Article I read from 2011 about Op Amps/Op Amps Rolling. I found it to be a highly practical guide on op amps.

http://nwavguy.blogspot.com/2011/08/op-amp-measurements.html?m=1

I have found often on audio threads many users using technical terms and highlighting specs and while hyping up an op amp because of this. It was extremely useful to know that not all op amp “benchmarks”  apply to audio quality in order to make an informed decision on what sounds great or what works in a circuit board! 

The main thing I have learned about op amps in audio is to prevent them from oscillating and of course performance in areas that are important to audio only applications! Moreover, lots of circuit boards are specially designed as an evaluation board for a specific op amp therefore it isn’t as simple as dropping in an op amp you may like or has a great reputation. 

When only discussing equipment for me it’s important that:

a. the source material is using genuine parts and knowing in some countries that they aren’t available as a point of reference. Nothing against op amps sourced in China it’s just when discussing a particular op amp one that comes from China vs it’s genuine counterpart in a DAP is like comparing Apples to Oranges. 

b. Getting to the Point. Many threads have technical jargon that may appear to be intelligent and knowledgeable but upon there conclusions often lack reference to how it relates to sound quality. (These tend to be most wasteful time consuming “noise” reads). 

My objectives are simple. Arm yourself with informed facts to make an informed decision and to have a constructive criticism made up in your mind of the useless jargon on the internet ‘hyped’ by marketing and regurgitated by threads as a form of “garbage in, garbage out.”


----------



## Rroff (Jun 14, 2019)

HeyManslowdown97 said:


> a. the source material is using genuine parts and knowing in some countries that they aren’t available as a point of reference. Nothing against op amps sourced in China it’s just when discussing a particular op amp one that comes from China vs it’s genuine counterpart in a DAP is like comparing Apples to Oranges.
> 
> b. Getting to the Point. Many threads have technical jargon that may appear to be intelligent and knowledgeable but upon there conclusions often lack reference to how it relates to sound quality. (These tend to be most wasteful time consuming “noise” reads).
> 
> My objectives are simple. Arm yourself with informed facts to make an informed decision and to have a constructive criticism made up in your mind of the useless jargon on the internet ‘hyped’ by marketing and regurgitated by threads as a form of “garbage in, garbage out.”



It is an age old contention when it comes to this subject. From many 100s of hours of messing about with this stuff (I have no professional background/training) there are subjective sides to this that defy any amount of on paper engineer testing.

Nwavguy's work is well known around these parts - some history involved.

I know the O2 amp design so well I can build it on prototype board practically in my sleep without referencing a schematic.


----------



## HeyManslowdown97 (Jun 14, 2019)

Rroff said:


> It is an age old contention when it comes to this subject. From many 100s of hours of messing about with this stuff (I have no professional background/training) there are subjective sides to this that defy any amount of on paper engineer testing.
> 
> Nwavguy's work is well known around these parts - some history involved.
> 
> I know the O2 amp design so well I can build it on prototype board practically in my sleep without referencing a schematic.



Yea not to mention $20,000 worth of testing materials to test the op amps. 

Majority of DIYERS are very practical and are primarily hobbyists with the occasional snob or two. I find myself humbled by trial and error  tweaking around but it can get expensive so it’s worth reading as much about something you want to accomplish beforehand. 

Relatively new to modding but would love to actually hear The OPA627 perform in it highest form for audio in a DAP specifically designed for it with a “high octane” DAP that’s got an Formula 1 esque control center to Monitor it’s  performance in real time that I cannot design! I feel that way Audio chips as well made by AKM and ESS. 

How are the O2 designs? Are they cool sounding??


----------



## CoiL (Jun 14, 2019)

CoiL said:


> This is insane-fast shipping! O_o
> 3-4 days from Arrow US to Estonia (east EU border-country) and my LM4562MAXNOPB and OPA1692IDR are HERE! O_o
> Unfortunately I ran out of SOIC-8 to DIP-8 PCB converter boards, so it takes time for me to get those, solder chips and compare against eachother and with OPA2228.


Got roll-able socket and chips soldered. Put things together and tried LM4562 first, I was shocked that left channel was making weird noises like EMI from PSU or something...
so I thought I fu''ed up something with soldering... but LOL, I forgot to attach headamp board and main PCB ground screws!
Huh... everything seems OK now and first impressions say that LM4562+OPA2228 is more detailed and tight compared to OPA2134. Will have to buy new OPA2134 chip to compared cuz I destroyed it because it was easier to remove by snapping off pins from chip.
Now will go and test OPA1692IDR+OPA2228 too.

Edit: One thing though, LM4562 seems to get pretty hot. Is it ok for such opamp or does it need to be cooled down? Or better not to use it?
OPA1692 seems to work @ about room temp. Latter seems to sound tad more "airy & open" by initial impressions.
Will let them "burn" and report sometime soon about sound.


----------



## HeyManslowdown97 (Jun 14, 2019)

CoiL said:


> I was shocked that left channel was making weird noises like EMI from PSU or something...
> so I thought I fu''ed up something with soldering... but LOL, I forgot to attach headamp board and main PCB ground screws!
> Huh... everything seems OK now and



I’ve done crap like that especially when your über focused in one area. Yea let us know how the combo works out for you with the Opa1692 + Opa2228! 

Heard nothing but great things about the LM4562 in the output stage! I’m gonna pick up the NJR version cuz it’s cheaper in bulk. Nifty little Op Amp that one!


----------



## Rroff

HeyManslowdown97 said:


> How are the O2 designs? Are they cool sounding??



The O2 is an engineering masterclass and measures very well but the "musicality" is a mixed story - personally I find it performs very well with actual current thirsty headphones (which are kind of rare these days) but find it lacking a certain something with headphones that like voltage i.e. Sennheiser HD600. Throwing about the price of the amp again (which goes against everything the amp stands for) on uprating certain parts to "boutique" components IMO makes a much more satisfying listening experience even though it is only of an order of "5%" differences. I also think nwavguy sabotaged himself in some ways it was designed to very strict tolerances and performs very well within those tolerances but can be improved on if you are operating outside of those tolerances - in some cases just spending a tiny little bit more on certain components gives it a much wider range of performance or compatibility capibility.



CoiL said:


> everything seems OK now and first impressions say that LM4562+OPA2228 is more detailed and tight compared to OPA2134.



This is why I say annoyingly as the LM4562 produces very detailed, tight output but IMO often comes at the expense of sounding a bit clinical which can be fatiguing.


----------



## CoiL

CoiL said:


> Edit: One thing though, *LM4562 seems to get pretty hot*. Is it ok for such opamp or does it need to be cooled down? Or better not to use it?
> OPA1692 seems to work @ about room temp. Latter seems to sound tad more "airy & open" by initial impressions.
> Will let them "burn" and report sometime soon about sound.


Any comments on that issue?


----------



## HeyManslowdown97 (Jun 14, 2019)

Rroff said:


> This is why I say annoyingly as the LM4562 produces very detailed, tight output but IMO often comes at the expense of sounding a bit clinical which can be fatiguing.



Oh, I get now what you meant about “clinical.” Plan on get it some LM4562 but it’s funny, you know, I’m not sure... we especially older people who remember the ‘sound’of the analogue world prefer its imperfections and ‘musicality’ and reject the ‘modern’ sound of digital etc. 

When something is too ‘clinical’ I’ll just burn a digital recording from vinyl or play a vinyl through the preamp. I found it ‘offsets’ the clinical sound with a more natural sound. It’s my version of a ‘cheat sheet’ and makes the analogue sound cleaner with more detail and also smooths out the harshness of the vinyl’s issues with tremble and muddled bass. Digital recording repair software also comes in handy on eliminating pops, hiss and cracks. Vinyl at its apex sounds best but it’s a diva and requires lots of tlc, no doubt 

We love our op amps to have low distortion. However, I have found like Jimi Hendrix a little feedback and distortion to sound pretty musical. Vinyl is the most distorted medium. Some prefer it since it sounds more warm and natural makes sense based on my biased opinion. 

I always question is, is a chicken before the egg when it comes to natural sounding vs clinical. Luckily we live in an age where you blend what’s old with something new! 

Happy medium is always the best way (if you can find that balance).


----------



## CoiL (Jun 14, 2019)

HeyManslowdown97 said:


> Yea let us know how the combo works out for you with the Opa1692 + Opa2228!


OPA1692+OPA2228 vs. LM4562+OPA2228 - I think both combinations sound very good by initial impressions but 1st combination sounds more "flowing" and natural with same amount of details. It sounds slightly more open&airy.
Second setup seems to have maybe slightly tighter and more "focused" imaging with instruments more focused and separated from background effects. Idk, it`s hard to explain.


Rroff said:


> This is why I say annoyingly as the LM4562 produces very detailed, tight output but IMO often comes at the expense of sounding a bit clinical which can be fatiguing.


Actually, I think OPA2228 might be "taming" LM4562 "annoyance" and sounds very good.
But I`m having problem LM4562 getting very hot


----------



## HeyManslowdown97 (Jun 14, 2019)

CoiL said:


> OPA1692+OPA2228 vs. LM4562+OPA2228 - I think both combinations sound very good by initial impressions but 1st combination sounds more "flowing" and natural with same amount of details. It sounds slightly more open&airy.
> Second setup seems to have maybe slightly tighter and more "focused" imaging with instruments more focused and separated from background effects. Idk, it`s hard to explain.



Sounds like you got the right rig for yourself and hit it out of the park! 

Ugh, I just LOVE when the airy sound is just right! Such nice and pleasant sound reminds of me of those blissful subtones you great in a tenor saxophone with natural air and tone!

You might wanna try opa1652 in lieu of the LM4562, it’s great too but I’ve heard it sounds better in the voltage stage. It’s got a nice soundstage with a beautiful airy sound!


----------



## CoiL (Jun 14, 2019)

Btw, I totally forgot about V5i-D as I can also swap it against OPA2134. In output stage it didn`t work but maybe as dac differential it will?
Will report back soon.

Edit: 
Anyway, by this short time I`ve compared LM4562 vs. OPA1692 paired with OPA2228 - I think I prefer SQ of latter combo. 
And dat LM4562 get so hot very fast in my setup anyway (sounds "intense" and good though).
Now need to get Stock opamp back and compare how much really difference is. I don`t like "new toy" syndrome and try to avoid it.


----------



## HeyManslowdown97

CoiL said:


> Btw, I totally forgot about V5i-D as I can also swap it against OPA2134. In output stage it didn`t work but maybe as dac differential it will?
> Will report back soon.
> 
> Edit:
> ...



Technically speaking the ‘airy’ sound is created by noise from gain. It’s the same in pictures the more you raise the gain you get noise in the frame. 

It’s really not natural but we love it aesthetically in sound and (even in selfies) lol.


----------



## CoiL

HeyManslowdown97 said:


> Technically speaking the ‘airy’ sound is created by noise from gain. It’s the same in pictures the more you raise the gain you get noise in the frame.
> *It’s really not natural* but we love it aesthetically in sound and (even in selfies) lol.


Whatever You say and makes You happy but I don`t think so 
I hear no "noise" whatsoever and hear improvements in details(micro) all over FR and rather talking about "air" which comes from more detailed and resolving highs (12kHz and up, which create that "air").  I hear "black background" and more detailed/clear instruments with rather less "distorted sound" and revealing more out of greatly mastered recordings (which is anyway basis of all replayable recordings). 

About OPA1692 + OPA2228 - I now definitely prefer this combo. It is more "balanced", has more natural timbre and more natural "soundscape/room" of recording.
LM4562 combo gets too "intense" and it`s like trying to decide whether to be surround speaker system or very good open-back headphone... but gets "stuck" in the middle, sometimes having congested small separated stage within large opera hall. I`m overemphasizing and trying to "paint a picture", hopefully someone understands.


----------



## HeyManslowdown97 (Jun 14, 2019)

CoiL said:


> Whatever You say and makes You happy but I don`t think so
> I hear no "noise" whatsoever and hear improvements in details(micro) all over FR and rather talking about "air" which comes from more detailed and resolving highs (12kHz and up, which create that "air").  I hear "black background" and more detailed/clear instruments with rather less "distorted sound" and revealing more out of greatly mastered recordings (which is anyway basis of all replayable recordings).
> 
> About OPA1692 + OPA2228 - I now definitely prefer this combo. It is more "balanced", has more natural timbre and more natural "soundscape/room" of recording.
> LM4562 combo gets too "intense" and it`s like trying to decide whether to be surround speaker system or very good open-back headphone... but gets "stuck" in the middle, sometimes having congested small separated stage within large opera hall. I`m overemphasizing and trying to "paint a picture", hopefully someone understands.



Noise is generated by pressure on your ears. 

You are raising the gain to get to those frequency. It’s alteration. Noise can be tempered (measured) or not. All reproduction of a recording is artificial.

The “airy” sound is an effect like reverb is to “room correction” or a byproduct of raising the frequency if you like to a certain level. 

Everything is video capture in “RAW” then compressed. The analogy is valid since we are talking about the same process of compression. 

You don’t want see lint on your shirt, just like you don’t want or hear feedback in a room. That’s “natural.” Therefore some is altered in post production. Hope this helps.


----------



## CoiL

HeyManslowdown97 said:


> ...you don’t want or hear feedback in a room. That’s “natural.”


This is where our mind&earsets differ and split - I want to hear reverbs&delays&echoes of room, guitar cabinet, drum shells etc. And there`s the fault in my eyes(ears) - ppl tend to "think on paper" and by "making it clean", making it actually worse by taking out too much and then we get artificial/digital/dry/ultra-clean sound that we actually do not hear in real life, in real band room/concert, with real instruments. But I honestly don`t want to discuss about this subject as it gets too offtopic.
Lets just say that sound is very subjective 

Back to opamps...


----------



## Ivan TT

CoiL said:


> Edit: One thing though, LM4562 seems to get pretty hot. Is it ok for such opamp or does it need to be cooled down? Or better not to use it?


Most likely it is oscillating (and most likely in MHz range, so will not be audible).
Interesting side-effect of oscillating opamp is that it effectively  biases it in class-A operation, giving intensity of sound (and power consumption/heat).
Sorry, I forgot where you are using it and in what stage, if it's output stage adding series resistors may help, also adding capacitors in feedback loop or small bypass caps on power supplies may help too (as some general directions towards fixing the issue).


----------



## HeyManslowdown97 (Jun 14, 2019)

CoiL said:


> This is where our mind&earsets differ and split - I want to hear reverbs&delays&echoes of room, guitar cabinet, drum shells etc. And there`s the fault in my eyes(ears) - ppl tend to "think on paper" and by "making it clean", making it actually worse by taking out too much and then we get artificial/digital/dry/ultra-clean sound that we actually do not hear in real life, in real band room/concert, with real instruments. But I honestly don`t want to discuss about this subject as it gets too offtopic.
> Lets just say that sound is very subjective
> 
> Back to opamps...



No such thing as a no distortion op amp. This is a fact. There’s always noise. Get super sensitive high impedance headphones and you will find it in the signal even in balanced. 

Moreover, we are NOT talking about our natural sense, we are talking about how they can be manipulated by audio equipment. There’s also nothing ‘natural’ in the production of music. Equipment must be clinical for it to sound good. We use  condenser microphone with clinical op amps  to capture the sound we want and not the noise we don’t want like air. So again it comes down to application of what sound the op amp you want create. 

My point is that the “airy” sound you hear is an effect otherwise it would be true on all op amps but if you tuned it even the LM4562 on a dedicated Circuit board to those frequencies or higher on the DAC using boost converters that operate on high frequencies, I’m sure you’ll get the airy sound. I know I have done it on other op amps haphazardly. I’m sure it can be done this way by playing around with resistance, capacitors, etc. as well?! The performance part measured in data sheets should be used as guidelines of how to optimize the desired sound but also how to get it work properly without oscillating.  

And we haven’t even talked about how digital filter alter the sound of the op amp with firmware apres it’s processed through the binary digital to analogue artificial conversion- more than one way to skim a cat.


----------



## CoiL

Ivan TT said:


> Most likely it is oscillating (and most likely in MHz range, so will not be audible).
> Interesting side-effect of oscillating opamp is that it effectively  biases it in class-A operation, giving intensity of sound (and power consumption/heat).
> Sorry, I forgot where you are using it and in what stage, if it's output stage adding series resistors may help, also adding capacitors in feedback loop or small bypass caps on power supplies may help too (as some general directions towards fixing the issue).


I`m using it as DAC differential opamp in Aune T1. Can I do something about it oscillating and overheating there? 
OPA1692 have been running some hours now and it isn`t even warm in that location.


----------



## Ivan TT

CoiL said:


> Can I do something about it oscillating and overheating there?


Is it the one on the main PCB or on the daughter card with DIP gain switches?
If the latter, increase gain, decrease volume.
If the former, adding 1nF film caps in parallel to feedback resistors and those between the inverted input and to the ground may fix it.
But I would not bother, TBH.
ЗЫ: Ah, double check solder joints/connections on all opamp pins, just fixed a DAC/AMP earlier this week that had dodgy soldering (done by your's truly lol) and was oscillating like crazy (as it should have)


----------



## CoiL (Jun 14, 2019)

Ivan TT said:


> Is it the one on the main PCB or on the daughter card with DIP gain switches?
> If the latter, increase gain, decrease volume.
> If the former, adding 1nF film caps in parallel to feedback resistors and those between the inverted input and to the ground may fix it.
> But I would not bother, TBH.
> ЗЫ: Ah, double check solder joints/connections on all opamp pins, just fixed a DAC/AMP earlier this week that had dodgy soldering (done by your's truly lol) and was oscillating like crazy (as it should have)


It`s on the main PCB but I think I will not bother to "stabilize" it. Pretty happy with OPA1692IDR + OPA2228PA, resolution & layering is very good with this combo and what`s interesting - mids are just amazing and not a bit laid-back nor too intimate "in You face". Also channel separation and soundstage width is expansive and I`m catching some micro-details I haven`t noticed so clearly before.
Tomorrow will try V5i-D too as DAC differential opamp.

Soldering is done nicely and this shouldn`t be cause of LM4562 heating problem.


----------



## HeyManslowdown97 (Jun 14, 2019)

CoiL said:


> I`m using it as DAC differential opamp in Aune T1. Can I do something about it oscillating and overheating there?
> OPA1692 have been running some hours now and it isn`t even warm in that location.



You can try switching the order. It could be overheating because it’s being overpowered by wrong circuitry on a dap or by the other op amp which is leading the oscillation. The slew time (speed) differential between the two amps may be what’s doing it. Although, I doubt it’s the latter and more likely the dap circuitry itself is not up to the task! 

Resistance and capacitor would work to slow it down but you’ll certainly need to know how to do with the right calculations. It isn’t wise to brainstorm this with online pics and making educated guesses unless you know what you actually doing and experienced in this area! 

I’d take it out before it burns out regardless since it’s being used in a stressful situation. I’ve have experienced burning out op amps trying to be a hero and make it work that in turn were deemed DOA afterwards and made them worthless.

These op amps will work forever if not put in stressful environments, it overheating is a sign it’s on it’s way to becoming worthless I wouldn’t risk it! You’re taking a chance with resistors, caps and trying to match it with data sheets brainstorming hypotheticals with hobbyists.

Update: Generally speaking the manufacturers will have the correct circuitry on the PCB to accompany the EXACT stock Op so the only reasonable way to get it 100% correct is to use a cross reference op amp tool (Ti and Ad have them so do reliable third party sites) for that exact stock op amp replacement which should be a PERFECT match for compatibility.

I’m glad you opted NOT to follow the hobbyist modding with no experience with your exact situation and your exact dap!


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## Rroff (Jun 14, 2019)

LM4562 should not be running hot - it is a touch more susceptible to power supply noise than many other opamps but usually that manifests itself as a distinct grainy or robotic effect on the sound. Do you know if the power supply rails are bypassed to ground with 0.1uf or similar high speed capacitors near the opamp(s)? a common cause of opamps running hot is a poor connection somewhere - something I've encountered more than once when rolling opamps are weakened a socket or soldering.




HeyManslowdown97 said:


> Oh, I get now what you meant about “clinical.” Plan on get it some LM4562 but it’s funny, you know, I’m not sure... we especially older people who remember the ‘sound’of the analogue world prefer its imperfections and ‘musicality’ and reject the ‘modern’ sound of digital etc.



That is why I like the OPA2228 it bridges the gap between the two worlds.



Ivan TT said:


> adding 1nF film caps in parallel to feedback resistors and those between the inverted input and to the ground may fix it.



Bandwidth limiting capacitors can definitely be a help but ideally they should be calculated with the resistors, etc. to make sure they are actually doing something useful and far enough away from the audio frequencies to minimise any distortion.


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## HeyManslowdown97 (Jun 14, 2019)

Rroff said:


> That is why I like the OPA2228 it bridges the gap between the two worlds.



Make Perfect sense and VERY practical as a “stock” dap. I love the idea of contrasting the digital and analogue world competing in the hardware. 

My guess is that the op amp in the circuitry in Aune A1 isn’t compatible to LM4562NA in this application or in the stage it’s being used  (which is rare since it’s very universal and not fussy based on what I’ve read. Anytime you add something in electronics some other part is losing “love” so power supply could be the problem but thats a byproduct if it wasn’t a previous problem. You really have to know exactly what the cause and effect of op amp is doing to itself and what it needs. Its also important to remember that adding resistance lowers the voltage. 

“Voltage varies directly with current. "R" is the constant of proportionality telling how much it varies. If I add in a resistor to a circuit, the voltage decreases. If you have a resistor in a circuit, with a current flowing through it, there will be a voltage dropped across the resistor (as given by Ohm's law)”

Depends on how forgiving daps are but generally I have found you can’t just op amp drop in some daps like nobodies business when it’s not designed to be developmental board but a fixed dap with very little leeway unless you know EXACTLY what you are doing and know how to hack the PCB with custom modding. In the end you gotta ask yourself is this worth it?


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## raoultrifan

@HeyManslowdown97, @Rroff I'm glad you are referring to the "unspoken" name of the O2 builder (BTW, your links and few words will probably get removed soon by an admin and you'll get warned).

There are basically YES and NO on both worlds: engineers that tell that two opamps having similar specs should sound the same, audiophooles that says that 100 USD opamps are sounding much better. Sometimes they are both right! 

On the first crowd, the engineering world (objective people), they are probably right on most scenarios, but there could be so many scenarios when some opamps are simply sounding a bit differently, mostly because it all depends on the surrounding passive electronic parts and the PCB layout, so some opamps might oscillate a bit or simply pick-up some EMI/RFI noises and act differently in the audio chain. E.g.: pre or post ringing, but also a 0.5dB gain or loss of amplification will definitely change how the soundstage will be perceived.

On the 2nd crown, the audiophools perhaps (subjective people), that are swapping dozens of opamps and are getting a different soundprint after every change. Hmmm...I've heard people swapping LM4562 with LME49720 and telling the world that is a complete "game change", like a getting from Moon to the March. Given the fact that the above two opamps are completely identical in terms of specs and manufacturer design, I would definitely say that it's most likely due to psycho-acoustics, but it might be also related to the fact that volume match was not done by a scope or REW + microphone, or listener position has been changed (or headphones were moved around the ears with 0.5-1 inch).

What it matters in the end is how everyone of us is liking the output sound and, of course, the opamps we used to not oscillate.  Ideally would be to have the setup measured somehow (RMAA, ARTA, REW etc.), just to be sure amplifier specs become better after swapping the opamps:
- THD (not higher than 0.001% if we really want the best out of our audio equipment)
- background noise (or THD+N for both items, which should be not higher than 0.01%, which represents only -80% of distortions + noise)
- DC output (less than 1mV for DACs and no more than 5mV to headamps, also 10mV should be fine for planars or power hungry cans)
- volume match (ideally less than 0.1dB between the channels, but usually less than 0.5dB is acceptable)

Some specs explanations could be found here: https://www.cambridgeaudio.com/en/blog/cd-specs.
A correlation between % and dB could be found here: http://www.sengpielaudio.com/calculator-thd.htm

What I'm trying to say is *if the designer of the DAC chip, for example PCM1717, states a THD+N of 90db which translates in a THD+N of 0.003%, after choosing the correct decoupling caps and opamps I should not deviate much from DAC chip's specs*. If an opamp will audio-orgasm my ears, but THD+N is getting worse with 10dB or even 20dB, then I should simply swap back the opamp till I'll get the best figure possible.




 
*The effects of LowPassFilter to the output THD+N *(source: http://www.ti.com/lit/an/sbaa055/sbaa055.pdf)
*
*​


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## CoiL

Rroff said:


> LM4562 should not be running hot - it is a touch more susceptible to power supply noise than many other opamps but usually that manifests itself as a distinct grainy or robotic effect on the sound. Do you know if the power supply rails are bypassed to ground with 0.1uf or similar high speed capacitors near the opamp(s)? a common cause of opamps running hot is a poor connection somewhere - something I've encountered more than once when rolling opamps are weakened a socket or soldering.


First of all, I don`t hear any "grainy or robotic" sound and secondly, can it be what @Ivan TT said?


Ivan TT said:


> Most likely it is oscillating (and most likely in MHz range, so will not be audible).
> Interesting side-effect of oscillating opamp is that it effectively  biases it in class-A operation, giving intensity of sound (and power consumption/heat).


...because other opamps work ok and I think there are no issues with soldering, otherwise OPA2228 wouldn`t also work as it should I belive?


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## HeyManslowdown97 (Jun 15, 2019)

raoultrifan said:


> On the first crowd, the engineering world (objective people), they are probably right on most scenarios, but there could be so many scenarios when some opamps are simply sounding a bit differently, mostly because it all depends on the surrounding passive electronic parts and the PCB layout, so some opamps might oscillate a bit or simply pick-up some EMI/RFI noises and act differently in the audio chain. E.g.: pre or post ringing, but also a 0.5dB gain or loss of amplification will definitely change how the soundstage will be perceived.



I agree but again it comes down to knowledge of knowing both theoretical knowledge and applying it to application and you can’t know all variables. Being a hobbyist like the majority of DIYERS I cannot say with absolute certainty lacking a electronic engineering I know everything on these threads (nor can most who  regurgitate falsity). 

As for removing chosen “words” it’s annoying but that’s the type of censorship you get from digital tribalism. FYI: they don’t like the usage of “audiofools” in these parts either. 

Lastly, when it comes to sound reproduction its an artifact so it’s a representation of an event NOT the event itself so it’s bothersome when people say things like it’s sounds “artificial” or “natural” (an opinion, not a fact) in objective terms. One mustn’t take these myths seriously.

There’s been a lot written about the “airy” myth being natural. Heck there are digital filters they do it (like the photo analogy I used) 

I once had a guy tell me that he doesn’t use silver because it’s too “bright” and I pointed out that most (if not all) parts on a dedicated dac uses some silver alloy or its also used in soldering paste or soldering. He became indigent and stuck to his dogma. 

As for the enthusiasm of op amp rolling I’ve been there, where I thought I have these Eureka moments which I’ve looked back on with cringe-worthy regrets. 

A simple solution to adding gain to do so in post production with a limiter or with an app in real time on an actual track, no need to ticker with the hardware resulting in hurting  yourself or your equipment as we don’t live in a 1996 world and like you said there are a variety of ways and solutions such as  firmware, digital filters, software, apps, etc that will get you a desired sound or “soundstage to be perceived” other than op amps which have a finite in what they can do to a perceived soundstage. 

In short even audio engineer today uses software, algorithms and don’t require actual physical space of say a mixing board only a Quality sound card with a op amp with good performance that functions. It’s when you start tinkering that you play with variates. If Op Amp Rolling requires fine tuning then it’s best to know what you are do or what the variables are. 

The “unknown” author wasn’t deliberate I didn’t frequent in these threads until recently. I’m not an “insider” and not sure if I want to be part of a bubble... you are honest and it’s always a pleasure to hear your feedback


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## CoiL

But what happen when You put "objective engineering ppl" in blind test and ask which setup sounds "better" and more "natural" without telling him anything about specs of opamps.
I`m guessing we would have different results but if that person already has heard "electrically pure" system, then his psychoacoustic perception of sound has already "coded" to it "being better & truer". But what if that "engineer" somehow hasn`t heard such system he "believes in due to specs" and presented with different (or exactly same) setups? I bet we would get different results in that case too. To me, we all are "coded" and "coding" ourself in some way and when it comes to "natural sound reproduction" I put ppl into 2 sides - ppl who belive only facts, calculations, specs etc. and ppl who just grasp music with their senses and stay true to what they personally hear to be right for their own ears. I place myself somewhere inbetween.
To me is just illogical to think that gear with "purest technical specs and build" sounds same way "natural" to everybody! That is thought insane in itself! We are humans (biological and intellectual) not specs on paper.


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## raoultrifan (Jun 15, 2019)

CoiL said:


> But what happen when You put "objective engineering ppl" in blind test and ask which setup sounds "better" and more "natural" without telling him anything about specs of opamps.[...]



Did that myself for few times; I remember very well when I had two identical ASUS Essence One MKii side-by-side and one had 4xMUSES01 in I/V and the other one had 4xNE5532 in I/V. So two people were 10 out of 10 inclined that the Essence One having the MUSES01 in I/V was having a bigger soundstage and somehow the sound was also more detailed (it was a blind test, we had no clue which one has the MUSES and which one the 5532). We were both right, but on the scope and RMAA and ARTA I realised the MUSES01 is causing a bit of post-ringing and also 2nd and 3rd harmonics are higher (about 20dB difference). In this particular case an worse THD and a bit of pre-ringing is causing the audio equipment to sound more...euphonic.

More details here: https://www.head-fi.org/threads/bur...sion-and-reviews.854912/page-18#post-14799047, but basically with MUSES01 I had a THD+N of 0.067% (-83.5dB) and with NE5532P I had a THD+N of 0.0024% (-92.4dB). So, in my case, NE5532P was able to provide a more accurate sound (very close to CD-Audio specs), but less euphonic than MUSES01 was able to offer.


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## HeyManslowdown97 (Jun 15, 2019)

CoiL said:


> But what happen when You put "objective engineering ppl" in blind test and ask which setup sounds "better" and more "natural" without telling him anything about specs of opamps.
> I`m guessing we would have different results but if that person already has heard "electrically pure" system, then his psychoacoustic perception of sound has already "coded" to it "being better & truer". But what if that "engineer" somehow hasn`t heard such system he "believes in due to specs" and presented with different (or exactly same) setups? I bet we would get different results in that case too. To me, we all are "coded" and "coding" ourself in some way and when it comes to "natural sound reproduction" I put ppl into 2 sides - ppl who belive only facts, calculations, specs etc. and ppl who just grasp music with their senses and stay true to what they personally hear to be right for their own ears. I place myself somewhere inbetween.
> To me is just illogical to think that gear with "purest technical specs and build" sounds same way "natural" to everybody! That is thought insane in itself! We are humans (biological and intellectual) not specs on paper.



Then you are asking their personal preferences as in subjectivity. That’s why datasheet only give performance results NOT what is a perceived sound quality. Rustling leaves in a movie aren’t “natural” they are added as effect during post. Cameras and microphones are placed in strategic locations to get the more intimate portrait to the viewership who subscribed to their favorite football clubs channel. Even stereo recordings are different then if you saw the performance live in their arrangements in what position you in, in the club or room, etc. 

The airy sound is an effect so is the “warmer” sound etc. and is how the op amp is tuned; it’s a personal preference, nothing more, nothing less.

Op amp rolling is also used by guitar in FX Pedels that give you certain sounds preferences but again they are also being replaced by software that can get the same effects without changing ANY hardware!


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## CoiL

CoiL said:


> Btw, I totally forgot about V5i-D as I can also swap it against OPA2134. In output stage it didn`t work but maybe as dac differential it will?
> Will report back soon.


Today tried out Burson V5i-D instead OPA2134 @ DAC differential opamp stage (+ OPA2228 @ output stage) - and it works! 
Initial impressions from first moment was - very clean sound, like pitch-black clean. A smidge "borderline" highs but not sibilant or harsh. 
Left it playing overnight and will do comparison against OPA1692IDR.


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## nesty

CoiL said:


> Today tried out Burson V5i-D instead OPA2134 @ DAC differential opamp stage (+ OPA2228 @ output stage) - and it works!
> Initial impressions from first moment was - very clean sound, like pitch-black clean. A smidge "borderline" highs but not sibilant or harsh.
> Left it playing overnight and will do comparison against OPA1692IDR.


@CoiL what dap are you using to experiment with those opamps? Thanks


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## CoiL

nesty said:


> @CoiL what dap are you using to experiment with those opamps? Thanks


Just read littlebit backwards... no DAP being used, it`s my desktop gear - Aune T1. Stock DAC differential opamp is OPA2134 and stock headphone amp board opamp is NE5532.


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## HeyManslowdown97 (Jun 17, 2019)

raoultrifan said:


> More details here: https://www.head-fi.org/threads/bur...sion-and-reviews.854912/page-18#post-14799047, but basically with MUSES01 I had a THD+N of 0.067% (-83.5dB) and with NE5532P I had a THD+N of 0.0024% (-92.4dB). So, in my case, NE5532P was able to provide a more accurate sound (very close to CD-Audio specs), but less euphonic than MUSES01 was able to offer.



This! (My guess) was Most likely a byproduct of MUSES01’s better transistors and overall construction than how it performed in benchmarks which in turn allowed the sound card overall “health” to sound better.

This is why Op Amp Rolling isn’t an exact science and why many manufacturers have already gone through the painstaking task of task what sounds the best for their products. Moreover, why would they pay 46 dollars for a MUSES01 vs NE5532 to get increasing overhead cost when the results aren’t that night and day! 

Those that do will often Jack up prices for the prosumer to make up the cost differential. In this case the sound card manufacturer assumes NO liability if the prosumer decides op amp roll and folk over the 46 dollars for the MUSE01. 

This is why Evaluation boards are the way to go if you really want to see how a op amp would truly sound to full  potential (in theory at least). 

In reading the unknown maker of O2 he had some interesting things to say about the OPA627 being a “Supercar” like a Ferrari that be can ONLY be used really on a racetrack. 

I’d STILL would want to test drive “Supercar” in its true element if given the chance but I have yet seen a DAP that’s specifically designed for the OPA627 or modded for it to hit all of its benchmarks and prevent it from oscillating!


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## CoiL

CoiL said:


> Left it playing overnight and will do comparison against OPA1692IDR.


In pairing with OPA2228PA (HO stage) - OPA1692IDR > V5i-D. 
In this configuration (as DAC differential opamp) V5i-D has very slight mid-bass/lower-mids "gloom", which I`m very sensitive to and it ruined some HQ live recordings for me. 
And I think the "pitch-black" clarity I mentioned before about V5i-D came actually from slight imaging "congestion" and slight lack or "air/space" as there are some ambient details subdued/lost in HQ live recordings. 
Currently sticking with OPA1692IDR + OPA2228PA until my new OPA2134UA chip arrives for comparison.


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## Ivan TT

CoiL said:


> Currently sticking with OPA1692IDR + OPA2228PA until my new OPA2134UA chip arrives for comparison.


You really have to try more of opamps from AD stables.
TI are always and inevitably coloured (except for maybe 827 that I don't have but someone mentioned here as AD-sounding).
AD8620 is pretty much end game, class of its own (unless opamp is compensating for something else in the chain, of course).


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## CoiL (Jun 18, 2019)

Ivan TT said:


> You really have to try more of opamps from AD stables.
> TI are always and inevitably coloured (except for maybe 827 that I don't have but someone mentioned here as AD-sounding).
> AD8620 is pretty much end game, class of its own (unless opamp is compensating for something else in the chain, of course).


Yeah, I have awsome result with ADA4841-2YRZ (DAC differential) + ADA4897-1ARZ (HO stage) in my modified DX50.

You meant AD8620 in DAC differential opamp stage or in HO stage?
Anyway, not sure if it is compatible since it requires almost double operating supply current and is rated max +-13V compared to OPA2134 +-18V ...if You meant dac stage.
Also it is 20€, which is quite a price for thing that I`m not sure about "improvement". I mean V5i-D isn`t also cheapest and 1) didn`t work in HO stage 2) ain`t providing me better SQ in dac stage also.

I really like how OPA2228PA sounds in HO stage and probably will stick with it. Now just need to figure out if OPA1692 provides me any improvement over stock OPA2134 in dac stage or not, latter I ordered new one because I cut off pins when removing from PCB. Maybe stock chip in dac stage turns out to be still slightly better and then my little curiosity wasn`t justified but anyway got some experience.

Currently I think most sound improvement came from HO stage opamp upgrade, which is weakest part of Aune T1. Maybe next step would be upgrading some resistors and SMD capacitors but not sure it provides my ears with noticeable improvement. I already have done primary and secondary stage power supply filtering capacitors upgrades, which gave clearly noticeable upgrade in SQ.


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## Ivan TT

CoiL said:


> You meant AD8620 in DAC differential opamp stage or in HO stage?


Differential.


CoiL said:


> HO stage


Does A1 not even have a buffered out?
If its HO out is driven by opamp as an output stage, and you are not listening to 600Ohm impedance earphones, there's few good opamps to consider:
OPA1688, OPA1612, AD826, LM7332


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## CoiL (Jun 18, 2019)

Ivan TT said:


> Does A (T)1 not even have a buffered out?


Honestly, I do not know. There is tube buffering stage but it is being applied only when using T1 as USB-sourced. If line-in is being used, then tube buffer is by-passed (You can even take tube out and LO(RCA) and HO are still working, if I remember correctly)... so, I assume HO is being driven only by opamp (NE5532 in stock)... LO then by OPA2134? Don`t know.


Ivan TT said:


> If its HO out is driven by opamp as an output stage, and you are not listening to 600Ohm impedance earphones, there's few good opamps to consider:
> OPA1688, OPA1612, AD826, LM7332


I`ve already tried OPA1612 and it was quite good: https://www.head-fi.org/threads/the-opamp-thread.432749/page-441#post-14991863

Here are some pics or Aune T1 PCB and parts: http://rockgrotto.proboards.com/post/119072


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## Rroff (Jun 18, 2019)

It is always going to be subjective but I don't like the OPA2132/2134 personally - they perform well enough but I always feel like somehow they make the music boring like someone playing the same tune for the 1000th time, accurate but with none of the passion of the first few times.

Can't remember if I've tried the LM7332 or not but I have various LM6xxx (such as the 6172) and 7xxx opamps and find them generally not optimal for audio use - a lot of them are design focussed for things like ADSL drivers and seem to use some kind of crude mechanisms for boosting slew rates or output current that work very well for their intended application but have negatives for audio and can also be quite picky about the circuit they are in becoming unstable very easily with many of them having specific notes about avoiding oscillation in the datasheet.

I'd definitely second checking out more of the AD series if you have the funds/time - the AD8066 as I've mentioned is one of my all time favourites and the 8620 is good.


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## CoiL (Jun 18, 2019)

AD8066 has even higher operating supply current demand and max dual-power supply is +-12V ...again, not sure if it is compatible in dac differential stage.
Any help with specs needed/not needed for opamp to work there without issues?
AD8066 though is noticeably cheaper than AD8620. That wouldn`t hurt my wallet if it is not compatible or doesn`t improve sound quality to my ears.

When I started to try out opamps in Aune T1, first thing I looked for was AD/ADA series opamps but most of them doesn`t seem to fulfill specs of OPA2134 drop-in replacement...


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## Rroff

Oh I'd forgotten about the voltage limitations - no real easy way around that.


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## HeyManslowdown97 (Jun 19, 2019)

According to NwAvGuy,

“…there’s little reason for a manufacturer to not to use an ideal op-amp. For another they likely have $50,000+ worth of test instrumentation and can precisely measure differences between op amps. They also designed the circuit the op-amp is in, so they better know what requirements matter most. But it seems a lot of audiophiles only see an inexpensive op-amp on a circuit board that needs replacing. They may not understand the rest of the circuit, have any way to know if they’re creating new problems, etc.”

In my experience this has been the case. Sometimes I will “get lucky” and op amp rolling with op amp that fits the specific board other times like a heart transplant it will reject it. 

The best method I’ve actually find to be the most beneficial is using a cross reference tool that gives you an accurate swap or list of op amps that are compatible from highest to lowest. 

In my experience it isn’t as simple as “plug and play” and often requires some adjustments. 

When DIYERs make arbitrary modifications based on what they have read or datasheets it is still doesn’t warrant their success! 

Circuitry is part art and part theory. Unless you really know what you are doing or have $50,000 worth of testing equipment it’s hard to what you doing or claiming to be true is actually true. 

The advantage of being a diy is that you can make a sound all your own. When you compare a dap that cost say $60 to say one that cost a couple of hundreds of dollars is that very little. But It’s the things that make the biggest difference. My only compliment about them is that I can’t mod them they way I want them to sound!

Even with high impedience headphones, I’ve gotten daps to play 5x their cost but when it comes to complete silence with zero crossfeed even the so-called “expert” Diyers haves issues with ground noise. It’s for this reason that a silenced low noise dap cost what they cost; you pay for the expertise, the hardware and software!

I yearn for the day Topping makes a portable Music Player as rarely use my desktop to listen to music all of the time. 

I have one of their daps and they nicely made!


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## Rroff (Jun 19, 2019)

Getting low noise is an interesting one - as well as good understanding from a design/engineering perspective such as understanding the nature of current paths, etc. there are all kind of little bits of esoteric knowledge, that an experienced engineer might know, that can make the difference that aren't necessarily intuitive or obvious from a design perspective at all.

You could follow every guide on good circuit design to the letter of the book but just moving where a screw goes through the board a couple of mm even could have an impact.


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## HeyManslowdown97 (Jun 19, 2019)

Rroff said:


> Getting low noise is an interesting one - as well as good understanding from a design/engineering perspective such as understanding the nature of current paths, etc. there are all kind of little bits of esoteric knowledge, that an experienced engineer might know, that can make the difference that aren't necessarily intuitive or obvious from a design perspective at all.
> 
> You could follow every guide on good circuit design to the letter of the book but just moving where a screw goes through the board a couple of mm even could have an impact.



Not to mention and endless amount of money to experiment if they work for the huge companies! In the audiophile world lots of business go out of business since the demand isn’t high for a niche market. That’s why prices are so high and there’s a much larger diy community. Large semiconductor companies who make op amp like TI and AD often pander to bulk rates since it gives them free advertising when a dap becomes successful in a manufactures design or it develops a cult following in the diy community from subjective op amp rolling. 

The current thing is interesting. I would imagine using the correct amount of film caps would work since if offsets current/voltage filters and allows sound to pass through. I’m sure this can also done with firmware engineering. There are designs that offer a combo of film caps coupled with aluminum ones to cut down on cost with the similar results. 

I’d also remark it’s not “intuition.” Daniel Kahnman wrote a book about this in his book Think Slow and Fast! It’s rather deliberate practice which is the ability to accurately find problems, work them out  and know how to fix them. So it’s not just the 10,000 hour rule as a accurate benchmark. Check the research out yourself.  

Trained engineers can build designs from Scratch so they know the ins and outs of their designs. When you are adding parts to an  existing design you don’t have such an intuition so-to-speak. That’s why is great idea to practice off boarding a learn how each circuitry works  in-conjunction how it  corresponds with the entire dap  holistically. That’s the only way to gain intuition heuristics in any process you are willing to learn. 

It also doesn’t hurt when you have access to $50,000 worth of testing equipment to  identify accurate performance problems and the know how to fix them.


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## Mad Max (Jun 19, 2019)

Well, goodbye ADA4075 in my O2's voltage gain, hello OPA1692. Just wow.
dat AD8022 bass, though, gotta love dat bipolar midrange, too


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## HeyManslowdown97 (Jun 19, 2019)

Mad Max said:


> Well, goodbye ADA4075 in my O2's voltage gain, hello OPA1692. Just wow.
> dat AD8022 bass, though, gotta love dat bipolar midrange, too



Have not tried nor used the O2 design by this is what the designer said is THE best for voltage Stage is to use the NJM 4556. I love to try this op amp. 

Apparently all the NJM Audio engineers made some pretty great op amps designed for audio with high current and low distortion that the unknown creator of the O2 is high on. The best part is they are dirt cheap!  

It’s also important to note that a lot of the MUSES are fancied up NJM designs so I’ve read. 

"NJM4556 OP AMPS: The NJM4556 op amps, by far, work the best in this design. No other dual DIP8 op amp can deliver even close to as much current at as low of distortion. Few op amps are made for driving headphones but the NJM4556 is. It also works well paralleled and not all op amps do. The TLC2062 is an acceptable substitute for headphones 32 ohms or higher and also provides about 3 times longer battery life. See: Low Power Option. The RC4580 is a very distant third if have no other choice.”

I’ve often seen this from some Diyers on this thread about gain settings and in turn become enraged by their blind arrogance to the said info. I don’t believe in pure gain as a panacea. 

O2 designer also says this which I happen to agree with as a rule of thumb in regards to gain. You can ALWAYS use a DAW limiter to your mod you files which essentially doesn’t the same thing and is safer. One word of causation anytime you use a limiter you are essentially compressing your files. But you can alway lower the dbs and double the tracks to make them fuller. This is also true when you want to add more fullness to crappy mp3. Some programs and apps can to this in real time with meta-data. 

Here’s what O2 designer says: 

“THE GAIN RESISTORS: Before you solder in the four gain resistors by the gain switch, you might want to consider different gains than the approximately 2.5X and 6.5X default values. You want just enough gain so typical music plays loudly enough with your headphones and source and not much more. Extra gain means using less of the volume control’s range, more noise, more distortion, and makes accidental headphone damage more likely. Here’s what you need to know about calculating gain:

Lower Is Safer - Lower gain settings make the amp less likely to damage headphones by limiting the maximum output voltage to only approximately what’s needed.
Lower is Cleaner – As shown in the first article, there’s a slight increase in distortion, especially at high frequencies at higher gain settings. Lower gains also result in lower noise.“


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## CoiL (Jun 20, 2019)

Mad Max said:


> Well, goodbye ADA4075 in my O2's voltage gain, hello OPA1692. Just wow.


Yeah, it`s really great opamp I think(hear)


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## Rroff (Jun 20, 2019)

HeyManslowdown97 said:


> Have not tried nor used the O2 design by this is what the designer said is THE best for voltage Stage is to use the NJM 4556. I love to try this op amp.
> 
> Apparently all the NJM Audio engineers made some pretty great op amps designed for audio with high current and low distortion that the unknown creator of the O2 is high on. The best part is they are dirt cheap!
> 
> ...



4556 is good (very good) for driving actual current demanding headphones but personally, despite having seen all the measurements, I don't rate them for stuff like the Sennheiser HD600 which like a reasonable amount of voltage and voltage "response" - while it does happen rarely I definitely catch some mid-range congestion at times and upper range vocals tend to be slightly coloured and harder to tell gender (I haven't noticed these things with lower impedance, higher current demanding headphones). The RC4580 is actually pretty decent - not exceptionally so - but a workhorse in most parameters with nothing terribly wrong, quite transparent even if a little lacking in "musicality" and well suited to audio use plus usually cheap as cheap - I wouldn't use one really for enthusiast application but it is an excellent choice for mass market consumer audio i.e. hanging off a 16bit/48KHz DAC dongle or embedded solution, etc.

A lot of fake "MUSES" opamps BTW seem to be re-badged 4556 or 4580s.


----------



## HeyManslowdown97 (Jun 20, 2019)

Rroff said:


> A lot of fake "MUSES" opamps BTW seem to be re-badged 4556 or 4580s.



True but it’s also true that MUSES are made by the same manufacturer: New Japan Radio. 

I’m sure that they share a lot in common. Would be interesting to know what the differences are and if you could make alterations to a dap to get a similar “MUSE sound” with caps and resistors tuned proper. 

(MUSES/Nichicon Also make capacitors that are like 1.50 each which can be coupled by film caps to reduce noise and strengthen the signal)

Ive tried the caps and they sound very nice giving the op amps warmer, musical sound. More warmer bass sound but lack a bit of  clarity. They could be a nice counterbalance to the NJM 4556 harshness and with a better signal you’ll get that spacious details. 

It’s hard to believe that the NJM 4556 makes vocal gender ambiguous though...


----------



## Mad Max

CoiL said:


> Yeah, it`s really great opamp I think(hear)


I tried ADA4841 in a Minibox-E+ years ago, quite the incredible sound, very analogue-like with warmth that's "just right".
I think I have 4897 somewhere put away, I haven't tried it yet, I should give it a go in my P3+.


----------



## CoiL

Mad Max said:


> I tried ADA4841 in a Minibox-E+ years ago, quite the incredible sound, very analogue-like with warmth that's "just right".
> I think I have 4897 somewhere put away, I haven't tried it yet, I should give it a go in my P3+.


I use ADA4841 in DAC differential + 2x ADA4897 in HO with my DX50 - wonderful result! So detailed and powerful/tight sounding combination (ADA4897 outputs 80mA). 
You should really give ADA4897 a chance


----------



## raoultrifan

HeyManslowdown97 said:


> Have not tried nor used the O2 design by this is what the designer said is THE best for voltage Stage is to use the NJM 4556. I love to try this op amp.[...]



Actually, the best Voltage-Amplification Stage is the default NJM2068 or, for a gain higher than 5X, LM4562/LME49720. The NJM/JRC 4556 is a very good output buffer able to drive headphones; it shouldn't be used in VAS, well...at least not inside the O2.



Rroff said:


> [...] A lot of fake "MUSES" opamps BTW seem to be re-badged 4556 or 4580s.


I always got those MUSES from authorized partners only; they're all listed on their website.


----------



## raoultrifan

HeyManslowdown97 said:


> True but it’s also true that MUSES are made by the same manufacturer: New Japan Radio.
> 
> I’m sure that they share a lot in common. [,...]



Well, yes and no. It's yes because it's indeed the same manufacturer, but it's no because MUSES opamps are manufactured by using a different process (in regard with Q&A, laser trim and time to complete the device) and on a different "bench". Also, legs are made of more copper and they can bend very easy.


----------



## HeyManslowdown97 (Jun 21, 2019)

raoultrifan said:


> Actually, the best Voltage-Amplification Stage is the default NJM2068 or, for a gain higher than 5X, LM4562/LME49720. The NJM/JRC 4556 is a very good output buffer able to drive headphones; it shouldn't be used in VAS, well...at least not inside the O2.



Yep that's correct. Thanks for the clarification. The NJM/JRC 4556 is best used as a output buffer able to drive headphones. 

I’d be curious to see how it fairs matched up with the TI’s improved BUF634 in testing! 

Impressive! 

“The NJM4556 is the optimal speed for audio use and no faster. This makes it very stable without any fussy special requirements, output inductors, or series resistance required.”

(Updated: Found this by the O2 maker) 



Spoiler: JRC NJM4555 vs BUF634



JRC NJM4556 – JRC is an interesting company with its roots in audio and analog. Unlike the big US companies like National, TI, etc. they tend to either offer lower cost versions of existing designs, or they design application-specific analog parts. I suspect the NJM4556 is one of the latter as it’s unique and almost made to order as a headphone op amp. It’s rated at 70 mA of current specified into 150 ohm loads. It was designed for audio use. In the eBay Cmoy it managed around 100 mA peak and overall rather impressive performance. In the same prototype setup as the OPA551 the NJM4556 performed significantly better in several tests and was much more stable. The NJM4556 is the optimal speed for audio use and no faster. This makes it very stable without any fussy special requirements, output inductors, or series resistance required. That’s worth a lot in this application. The one remaining problem is the output current. The 4556’s 70 – 100 mA obviously falls short of the 166 mA requirement. But, the 4556 is a dual op amp with two well matched amps on a single silicon substrate (die). What will it do with both amps in parallel to double the current capability? The answer is, with appropriate measures, it does good things! It produces over 200 mA which approaches the 250 mA of even the LME49066 and BUF634 above. It turns out using one 4556 with paralleled sections for each channel meets all the requirements. I’ve also tried to blow one up with brief short circuits playing music at clipping and so far so good. And you can buy 7 of them for the price of one OPA551. To my knowledge, this is the first time the 4556 has been paralleled for headphone duty and it’s a big reason the O2 can deliver great performance at such a low price.
2-15 OUTPUT STAGE DESIGN – With the 4556 specified, the rest of the output stage needs to be optimized. First, you usually can’t simply connect two op amp outputs in parallel. They may not share the current equally and any difference in offset voltage will significantly increase the quiescent current. Measurements with the dScope demonstrated just 1 ohm of series resistance works nicely with half a dozen different 4556 samples (some from different production lots). These are effectively in parallel so the output impedance is approximately 0.5 ohms which is well under the 2 ohm goal.”



Interesting tidbit about the lasers trims and copper manufacturing differences. I wonder if the process is improved makes the fundamental improvement to better circuitry in overall performance or it’s just the claims of making up R&D cost. If so it doesn't justify the jacking up the price hikes from .73 cents to 46 dollars! That’s a shrewd business model which is driven by subjective forum-based audiophile self branding marketing of the MUSES line. 

The funny thing about the counterfeit markets is that is feeds off this model with the popularity of certain models desired by audiophiles. I for one won’t mind and prefer if the say the Chinese market development their own designs in regards to OP Amp as originals. But then again China isn’t known for their originality and like to copy existing designs or take an existing op amps and repackage them into the more desired op amp sought by audiophiles.

There are some sellers on AliExpress that do sell original op amps and it would be interesting if they were tested with the same vigor as the genuine popular ones found on threads like this. The more the merry (provided they don’t flood the markets with counterfeits that are inferior in quality). Fat chance that will happen! 

It just seems that unless it comes from the major Chinese manufacturers like Huawei and Xiaomi (that don’t make op amps) it appears that the Chinese can’t make nor design their original designs[/Spoiler]


----------



## Rroff

raoultrifan said:


> Actually, the best Voltage-Amplification Stage is the default NJM2068 or, for a gain higher than 5X, LM4562/LME49720. The NJM/JRC 4556 is a very good output buffer able to drive headphones; it shouldn't be used in VAS, well...at least not inside the O2.



Good catch on that one! yes the 4556's advantage is its ability to deliver current with low distortion when you actually need a decent buffer.



HeyManslowdown97 said:


> “The NJM4556 is the optimal speed for audio use and no faster. This makes it very stable without any fussy special requirements, output inductors, or series resistance required.”



One of my concerns here - though he is right in what he says - the 4556's slew rate and other relevant specifications are quoted as _typical_ rather than _minimum_ as you see on some other opamps - which potentially means there are situations where they are performing below an adequate level maybe I think he does provide some graphs but how comprehensive over a wider usage scenario range they are valid for I don't have the experience to know - though there is a bit of headroom there isn't a huge amount depending on the actual operating range and what the actual minimums and how critical they are is. While theoretically it shouldn't matter I definitely see (hear) the best results with things like slew rates approaching double figures rather than in the 2-5 range or so - IMO it is one of the reasons the OPA2228 is generally preferred over the OPA2227 despite on paper being very closely related opamps.


----------



## HeyManslowdown97

Rroff said:


> While theoretically it shouldn't matter I definitely see (hear) the best results with things like slew rates approaching double figures rather than in the 2-5 range or so - IMO it is one of the reasons the OPA2228 is generally preferred over the OPA2227 despite on paper being very closely related opamps.



Honestly it’s not such an issue to select a high performance op amp that’s sound preferences you prefer provided you know to how to monitor its performance and give it what it needs fussy requirements, output inductors, series resistors, etc. 

Unless, op amp rolling is a perfect swap. I (personally) don’t have the skill to fine tune a op amp that I like the sound of. 

I don’t think it’s matter of saying yourself  ‘any’ Dual op amp will do to swap for another dual op (per se) as the only requirement nor if this or that op amp is performs well in a particular stage. I think it’s more than just plug and play. 

I have no idea how to Proof if whether an op amp is perform up to task unless they’re are noticeable signs like overheating, noise, volume issues, etc. 

I’d love to have the know-how to fine tune an op amp and get to perform like it should and hit all of its benchmarks that are pertinent to audio signals. 

As an open question I love if someone could provide the know-how or the procedure of how to give the op amp with the sound you love som’ much needed love to make it perform healthy on a dap.


----------



## Rroff

At a basic level you can feed various test frequencies and patterns through an opamp while monitoring the output with an oscilloscope to check the behaviour is as expected. That very quickly identifies things like clipping and ringing even with test equipment in the $/£/€100 kind of price range.


----------



## raoultrifan

HeyManslowdown97 said:


> Yep that's correct. Thanks for the clarification. The NJM/JRC 4556 is best used as a output buffer able to drive headphones.
> I’d be curious to see how it fairs matched up with the TI’s improved BUF634 in testing![...]



Well, BUF634 and LME49600 are dedicated for use as output buffer, these will strive NJM4556 when using planars or hard to drive cans. It's like comparing gold with silver, so not quite OK to compare an opamp for general use (even paralleled) with another one especially designed to be used as output buffer.



HeyManslowdown97 said:


> [...] That’s a shrewd business model which is driven by subjective forum-based audiophile self branding marketing of the MUSES line[...]



MUSES01 measures and sounds very well in my PLAYMATE, although not the same happens inside PLAY, nor Essence One, so it's all about the surrounding circuitry, power supply ripple & noise, PCB traces, ground plane and...probably some luck too. 

MUSES02 sounds and measures better than LME49860 when used inside HPA-3B, same applies to V5 and V6 opamps from Burson, although same expensive opamps may not measure so well inside PLAY. etc.


----------



## HeyManslowdown97

raoultrifan said:


> Well, BUF634 and LME49600 are dedicated for use as output buffer, these will strive NJM4556 when using planars or hard to drive cans. It's like comparing gold with silver, so not quite OK to compare an opamp for general use (even paralleled) with another one especially designed to be used as output buffer.
> 
> 
> 
> ...



Ugh, why must it be so complicated! Is there a way you can help them play nice in a specific dap I.e. resistor series, output inductors, etc!


----------



## raoultrifan

More or less, they'll all sensitive to voltage noise and also external noises too (EMI/RFI), so it's normal to perform differently from one player to another (more or less, most likely inaudible to most of us).


----------



## HeyManslowdown97

Th





raoultrifan said:


> More or less, they'll all sensitive to voltage noise and also external noises too (EMI/RFI), so it's normal to perform differently from one player to another (more or less, most likely inaudible to most of us).



The thing I’m confused about is the non inverting vs inverting op amps with the resistor series location and how it operates on the dap. 

Does the negative feedback loop operate inside the op amp or does the schematics have to be calculated on the dap itself. It’s stuff like that I don’t know think about. 

I’ve had instance where it isn’t a “clean” swap between op amps and It’s always a head scratcher since I KNOW there's a reason and yet I don't what it is. 

I also find that some op amps in particular package like Vsson??? are use there own pcb to be a plug and play op amp. (The 1622 comes to mind.)


----------



## raoultrifan

All I can tell is that today amplifiers are measuring so well that I don't think you could pick-up the inverting vs. non-inverting amplifier in a properly conducted A/B test.

For me, the most important advantage of an inverting amplifier is its ability to operate with gains lower than 1X, which means lower background noise and less power, so best headamp for very sensitive headphones.


----------



## Rroff (Jun 23, 2019)

HeyManslowdown97 said:


> I also find that some op amps in particular package like Vsson??? are use there own pcb to be a plug and play op amp. (The 1622 comes to mind.)



The 1622 is a 10 pin propitiatory IC that isn't drop in pin compatible with the generic 8 pin opamp - I don't really recommend using it on a breakout board as a drop in replacement for an 8 pin opamp as that will degrade its performance and potentially run into some of the same kind of issues like with the virtual ground on a basic CMOY amplifier design while not fully utilising the chip for some of its audio specific features like enable (which can be driven by GPIO, etc.).



HeyManslowdown97 said:


> The thing I’m confused about is the non inverting vs inverting op amps with the resistor series location and how it operates on the dap.
> 
> Does the negative feedback loop operate inside the op amp or does the schematics have to be calculated on the dap itself. It’s stuff like that I don’t know think about.



I think you are over-thinking this aspect - most audio applications use non-inverted with a negative feedback loop and you do have to take into account external components that are part of the feedback loop - whether an opamp is unity gain stable or not and whether internally compensated on opamps optimised for higher gains. I'd recommend spending some time reading up on https://tangentsoft.net/ (such as the opamps in detail section under audiologica) as it gives a good grounding in the basics.



HeyManslowdown97 said:


> I’ve had instance where it isn’t a “clean” swap between op amps and It’s always a head scratcher since I KNOW there's a reason and yet I don't what it is.



Often it will come down to things like bandwidth limiting capacitors that are part of the feedback loop which might be required to stabilise some opamps but might destabilise others and what kind of circuitry is on the output to deal with things like capacitance which some opamps might be sensitive to - some opamps for instance without a couple of resistors on the output can be upset by trying to drive headphones with long leads like the Sennheiser HD600 while others might be perfectly happy.


----------



## HeyManslowdown97 (Jun 23, 2019)

Rroff said:


> The 1622 is a 10 pin propitiatory IC that isn't drop in pin compatible with the generic 8 pin opamp - I don't really recommend using it on a breakout board as a drop in replacement for an 8 pin opamp as that will degrade its performance and potentially run into some of the same kind of issues like with the virtual ground on a basic CMOY amplifier design while not fully utilising the chip for some of its audio specific features like enable (which can be driven by GPIO, etc.).



Oh I’m well aware of the op amp 1622 and alerted an “experted” modder about CMOY reference and on Head fi thread and reported me and had me banned from a thread belligerently called me all kinds of labels and  hid behind  esoteric knowledge with embellished empirical jargon but I KNOW even as a  newbie the he was full of crap! 

Unfortunately, on the thread he had developed a cult-ish following and sadly they “sided” with him. My intention wasn’t to question his ability nor knowledge to make him look bad but that I was skeptical of what he was saying because it didn’t sound right (based on what I read)!

Funny part was he did say he had virtual ground issues with his mod and wanted to trade with members the said portable dap to conduct “ground experiments” to eradicate the problem. Lol.


----------



## Rroff

HeyManslowdown97 said:


> Oh I’m well aware of the op amp 1622 and alerted an “experted” modder about CMOY reference and on Head fi thread and reported me and had me banned from a thread belligerently called me all kinds of labels and  hid behind  esoteric knowledge with embellished empirical jargon but I KNOW even as a  newbie the he was full of crap!
> 
> Unfortunately, on the thread he had developed a cult-ish following and sadly they “sided” with him. My intention wasn’t to question his ability nor knowledge to make him look bad but that I was skeptical of what he was saying because it didn’t sound right (based on what I read)!
> 
> Funny part was he did say he had virtual ground issues with his mod and wanted to trade with members the said portable dap to conduct “ground experiments” to eradicate the problem. Lol.



There is a whole load of information about the IC from johnc124 around the web about it - he actually works for the company that developed and manufactures the chip I assume you aren't getting him mixed up with a modder? there are all kinds of potential problems with DC offset, etc. if you just slap one into a circuit on a breakout board.


----------



## HeyManslowdown97 (Jun 24, 2019)

Rroff said:


> There is a whole load of information about the IC from johnc124 around the web about it - he actually works for the company that developed and manufactures the chip I assume you aren't getting him mixed up with a modder? there are all kinds of potential problems with DC offset, etc. if you just slap one into a circuit on a breakout board.



Nope, I cited johnc124 as well and am well aware that he’s the lead marketing guy for that particular project at TI who said it wasn’t a diy friendly package. My citation taken from “DIYAUDIO” thread when it was launched was the exact thing I used as to why I thought it wasn’t just matter of slapping on a circuit board and the dude (aka: modder) went ballistic. 

My main point was that it wasn’t designed In the way he was using it & he became enrage with every post I posted of potential problems with what he was doing but since he sounded like knew what he was doing provided “changelogs”, pics of his modifications and sounded  convincing and influential people just took his word for it.


----------



## Ivan TT (Jun 25, 2019)

Rroff said:


> there are all kinds of potential problems with DC offset, etc. if you just slap one into a circuit on a breakout board.


In defence of OPA1622 on a circuit board (cheap ebay version), it works just fine in practice, even if in theory there are some valid concerns about using it on DIP8 PCB.

Ground is derived from splitting rails using resistors indeed, but it does not manifest in increased DC offset (I observe sub-1mV DC offsets in my fully DC-coupled setups), and John mentioned something like 3-6dB noise increase in noise above 10kHz if using this arrangement, which is negligible (and probably would still be below many opamp's noise anyway).

Ebay board houses 2 power bypass caps (not sure if John's had those), which helps.
I ususally replace resistors with extra set of caps (actually, I replace resistors and stock caps using 0805 0.1 and 22uF caps) and then provide connection to ground via extra wire, if using OPA1622 as a permanent solution. I also customary configure them as voltage followers, as they work as buffers just fine (and it requires only 2 bridges on DIP8 PCB board).

But also OPA1622 is perfect for driving HP directly, as it has high capacitive load ability, high current output, short protection and lowish output impedance, so even on a PCB board it is perfect replacement for any DIP8 socketed opamp driving headphones well worth consideration.

Downsides of OPA1622 that I noticed: low-level pop when powering up (even when using delayed power on using enable pin), it is also quite susceptible to EMI.


----------



## Headmate

Planning to swap out the buffers on Xduoo XD05, 

BUF634U vs HA-5002 vs LMH6321

Anyone can help are these inter changeable and sonic differences?


----------



## HeyManslowdown97 (Jun 25, 2019)

Headmate said:


> Planning to swap out the buffers on Xduoo XD05,
> 
> BUF634U vs HA-5002 vs LMH6321
> 
> Anyone can help are these inter changeable and sonic differences?



Can’t really comment on the comparisons head-to-head. However I got the upgraded BUF634AU which is in prototypical and can only be purchased directly from TI. 

http://www.ti.com/product/BUF634A

All I can say is, it’s VERY powerful and my guess it requires a dap that can handle it. 

The “sound” I found was overpowering and overkill for when paired with differential operational amp of personal choice unless your dap is severally under power (I’m guessing) it would work well?!..Then again if you already know what pairs well with the BUF634 you are ahead of the game! 

Curious with what the feedback the tread will say in response to your question as it’s an interesting one!

The HA-5002 looks sweet on paper as a hybrid CMOS that operates as both a buffer amp and regular amp but I have no clue what it sounds like sonically! Curious what others’ thoughts are experiencing this one!


----------



## HeyManslowdown97 (Jun 25, 2019)

Ivan TT said:


> Ebay board houses 2 power bypass caps (not sure if John's had those), which helps.
> I ususally replace resistors with extra set of caps (actually, I replace resistors and stock caps using 0805 0.1 and 22uF caps) and then provide connection to ground via extra wire, if using OPA1622 as a permanent solution. I also customary configure them as voltage followers, as they work as buffers just fine (and it requires only 2 bridges on DIP8 PCB board).



”Ebay board houses 2 power bypass caps (not sure if John's had those), which helps.
I ususally replace resistors with extra set of caps (actually, I replace resistors and stock caps using 0805 0.1 and 22uF caps) and then provide connection to ground via extra wire, if using OPA1622 as a permanent solution. I also customary configure them as voltage followers, as they work as buffers just fine (and it requires only 2 bridges on DIP8 PCB board).”

I take this info as a grain of salt as one’s personal opinion and bias as it was stated that it was purchased on eBay and isn't certified AB Tested nor tested by the widespread DIYER community as a general consensus. Moreover these are arbitrary modification with subjective hear testing results. I would remind everyone this is a DIYER not an TI engineer stating these findings as facts. Unless, John himself gave direct feedback to this mod as being trustworthy, I wouldn't trust it.

You could probably get similar sonic results by using opa1688 soic 8 that is more diy friendly sans questionable modifications.


----------



## Headmate

HeyManslowdown97 said:


> Can’t really comment on the comparisons head-to-head. However I got the upgraded BUF634AU which is in prototypical and can only be purchased directly from TI.
> 
> http://www.ti.com/product/BUF634A
> 
> ...



Hey! after quick research I gathered: All 3 are available in SOIC8

HA-5002 sounds more spacious, clearer than BUF634U (which is a tad warm sounding & veiled) but the problem is that HA-5002 does not have output current short protection - headphone jack removal during usage can potentially burn out the buffers?

LMH6321 not enough user feedback. read it has a heatsink underside.


----------



## HeyManslowdown97

Headmate said:


> HA-5002 does not have output current short protection - headphone jack removal during usage can potentially burn out the buffers?



You definitely want to err on the side of caution so it would be best to get feedback of users who have experienced with the HA-5002. 

DAPS made today have so many protection and safeguards that make them virtually idiot proof but again this is just a guess! 

That said if the description is accurate I love to try the HA-5002 as spacious and bandwidth is more of an importance for me than warmer as you can always get that from a op amp is your personal liking. 

I have found its harder to find op amps that are spacious and not in a faux way. It's like that with firmware as well!


----------



## Headmate

HeyManslowdown97 said:


> You definitely want to err on the side of caution so it would be best to get feedback of users who have experienced with the HA-5002.
> 
> DAPS made today have so many protection and safeguards that make them virtually idiot proof but again this is just a guess!
> 
> ...



Looking at specs, LMH6321 appears safer to solder in, considering it's made by Texas Instruments as well, and it's specs mostly match with BUF634U (similar input current 20ma),  HA5002 has 8.5ma input current. 


For spacious sounding opamp, try AD8065, OPA627, LME49710


----------



## Rroff (Jun 25, 2019)

Headmate said:


> LMH6321 not enough user feedback. read it has a heatsink underside.



I've used the LMH6643 quite a bit as it can deliver reasonable current reasonably linearly but it is a lower voltage range part more suited to USB applications, etc. and it is slightly coloured but nothing terrible - however I don't recommend the 6000 and 7000 series for audio use - they are mostly designed for things like DSL line drivers and professional buffer applications like video or other optical processing and the implementation used to get high slew rates or large current capabilities doesn't tend to be optimal for audio - the 6643 does atleast have some audio consideration in its design albeit not a main focus.


----------



## HeyManslowdown97

Headmate said:


> Looking at specs, LMH6321 appears safer to solder in, considering it's made by Texas Instruments as well, and it's specs mostly match with BUF634U (similar input current 20ma),  HA5002 has 8.5ma input current.
> 
> 
> For spacious sounding opamp, try AD8065, OPA627, LME49710



Oh yeah thanks I'm well aware of the OPA627 being spacious. 

I was referring to the Buffer Application with those qualities: clear and spacious. 

When it comes to specs unless someone more experienced who tests this stuff with a clear ”winner” I’ll normally commit the faux pas of trusting my ears (aka subjectivity). 

There is certainly different schools of thought about functionality vs aesthetics in personal sound. So it's kind of an Art. Having made many mistakes and cringe-worthy newbie posts on Head-Fi. I “try” to stay on the science side of things and keep my subjectivity at bay. 

I read this in head fi guidelines and try to make post with this in mind at all times. 

“I think that every review, impression, or de facto "this product sounds better than that" statement would be made immeasurably better if it was required to have these three disclaimers:

1. This is only my opinion.
2. I am biased, like everyone else.
3. I have not heard everything in the world.”


----------



## Rroff (Jun 25, 2019)

Ivan TT said:


> In defence of OPA1622 on a circuit board (cheap ebay version), it works just fine in practice, even if in theory there are some valid concerns about using it on DIP8 PCB.
> 
> Ground is derived from splitting rails using resistors indeed, but it does not manifest in increased DC offset (I observe sub-1mV DC offsets in my fully DC-coupled setups), and John mentioned something like 3-6dB noise increase in noise above 10kHz if using this arrangement, which is negligible (and probably would still be below many opamp's noise anyway).
> 
> ...



My intention isn't to be negative of the 1622 - it is very good at what it is intended to do and if you have the knowledge to get the best out of it in a DIP-8 context as you obviously do then another story but I don't recommend people just buy them pre-mounted on a breakout board and stick them into any old amp/DAC though obviously that also goes for a lot of regular opamps as well.



HeyManslowdown97 said:


> I was referring to the Buffer Application with those qualities: clear and spacious.



Good buffer opamps are a bit limited in terms of what is available  if you actually need reasonable amounts of current but not too high the NJM/JRC4556 is perfectly acceptable but it isn't my first choice in situations where some kind of buffer helps with performance but you don't need lots of current.

Another option if you need current is the OPA551 but without reasonable knowledge of how to use it and ideally a good idea of the kind of support circuitry that would be best practise with it you can easily make something that kills the opamp or what you have connected to it :s (also similar story for the AD8397).

My personal preference at the moment is the 1692 and parallel them if I need more current than one can provide (don't just solder them to each other directly LOL).


----------



## HeyManslowdown97 (Jun 25, 2019)

Rroff said:


> My intention isn't to be negative of the 1622 - it is very good at what it is intended to do



Exactly, it wasn’t intended for this usage if it was they would have made a soic for it! 

The biggest seductive quality of op amp 1622 is that it’s intended to be use to power low impedance headphones which ALSO requires headphone amps or daps that are specifically designed for. 

Not that it is “wrong” to attempt to turn a dap and op amp NOT designed for IEMs to be a constructive critic but it is very unorthodox. Just because it can be done doesn’t mean you get the optimal results or that it’s for everyone and may also damage your equipment in the long run.  

It’s seems to a be seductive quality to attempt this modification to lower resistance to zero and implement op amp 1622. Even so the majority of portable commercial headphone jack only have an output of 12 volts and by the time a battery powered series circuitry hits your ears it’s more like 3VDC. I would imagine you do hit a ceiling. Not sure if current based headphones are better for IEMs (resistance often lowers current) but even so if the dap chip isn’t performing at its optimal specs because of space restraints it’s a moot point to attempt this in my view to get lower dbs if you cannot preamp those frequencies anyway. And is it really worth all that trouble to get less than 2% of better audio. I don’t think so.

Updated: 

DIYER

“Downsides of OPA1622 that I noticed: low-level pop when powering up (even when using delayed power on using enable pin), it is also quite susceptible to EMI.“

TI does make an evaluation board that includes a headphone jack output for only 25 dollars. I would sincerely doubt that John would endorse a circuitry found on EBAY. Lol. 

TI Engineers: 

Features

Eases design by providing a quick and simple way to evaluate the OPA1622

Audio jack provided on the EVM allows for quick listening tests of the OPA1622

Input connectors on the EVM provide an easy way to evaluate the OPA1622 using an audio analyzer or an audio DAC that will be used in an end product

The EVM design allows access to the Enable pin of the OPA1622 to test for a "pop" and "click" noise while the OPA1622 is being enable and disabled

http://www.ti.com/tool/OPA1622EVM

DIYER 

“But also OPA1622 is perfect for driving HP directly, as it has high capacitive load ability...lowish output impedance, so even on a PCB board it is perfect replacement for any DIP8 socketed opamp driving headphones well worth consideration.“

TI Engineers: 

“With high linear output current of 80mArms, the OPA1622EVM can drive headphone loads of 8Ω, 16Ω, 32Ω, 300Ω, 600Ω and higher”

For your consideration: Typically the lower the Ohms, the easier the headphones (& IEMs) are to drive. Provided that dap/headphone can push out 8 Ohms or above. In layman’s terms a dap/headphone designed for it. 

Most headphones on the market are less than 8 Ohms and most desktop dac or headphones would require their own power supply to carry the high load of 300-600 Ohms. Therefore it’s not a “perfect replacement” as plug and play for anyone driving any old headphones.


----------



## Rroff (Jun 25, 2019)

Another one I had a play with was the LM6172 - I think I was having problems getting it stable maybe - didn't get around to scoping it - but for audio it was quite grainy and coloured.

I might be getting a bit mixed up between which of the LM and LMH ones are in the same series and/or I've tried - tried a few in the 6000 and 7000 numbering but might be getting mixed up which were the LM and which were LMH. (Definitely LMH6643 and LM6172 though as I have them in my opamp box).


----------



## FritzS

Headmate said:


> Hey! after quick research I gathered: All 3 are available in SOIC8
> 
> HA-5002 sounds more spacious, clearer than BUF634U (which is a tad warm sounding & veiled) but the problem is that HA-5002 does not have output current short protection - headphone jack removal during usage can potentially burn out the buffers?
> 
> LMH6321 not enough user feedback. read it has a heatsink underside.



HA-5002  have an output current short protection by two resistors - please see page 5
https://www.renesas.com/eu/en/www/doc/datasheet/ha-5002.pdf

The BUF634 could be driven into a small Class-A region 15 .. 20mA by the ESD bridge, BUF634a only 8.5 mA
https://www.ti.com/lit/ds/symlink/buf634.pdf
https://www.ti.com/lit/ds/symlink/buf634a.pdf


----------



## Headmate

FritzS said:


> HA-5002  have an output current short protection by two resistors - please see page 5
> https://www.renesas.com/eu/en/www/doc/datasheet/ha-5002.pdf
> 
> The BUF634 could be driven into a small Class-A region 15 .. 20mA by the ESD bridge, BUF634a only 8.5 mA
> ...




Thanks!

are the pinouts of HA5002 and BUF634 same? could they be safely swapped in?


----------



## FritzS

Headmate said:


> Thanks!
> 
> are the pinouts of HA5002 and BUF634 same? could they be safely swapped in?



Please read the data sheets!

https://www.renesas.com/eu/en/www/doc/datasheet/ha-5002.pdf

https://www.ti.com/lit/ds/symlink/buf634.pdf
https://www.ti.com/lit/ds/symlink/buf634a.pdf


----------



## Headmate

As per the data sheets,* HA5002 is NOT a direct replacement for BUF634*, owing their different pin layouts. Good thing I read them 

BUF634A is now available as a direct replacement/upgrade for BUF634U with exact same pin layout, with better slew rate and bandwidth.


----------



## HeyManslowdown97 (Jun 26, 2019)

Headmate said:


> BUF634A is now available as a direct replacement/upgrade for BUF634U with exact same pin layout, with better slew rate and bandwidth.



What, the ha5002 isn’t a direct swap with the BUF634! 

I have the BUF634A it’s great if you need extra oomph but sound wise I found it overpowering. Maybe it’s great for high impedance headphone (80 Ohms or more??) 

Was really looking forward to swapping the Buf634A with the ha5002! 

There might be a adapter that re-circuits  the pins of the Ha5002 to be a direct replacement for the BUF634?! 

Will do some digging! 

Sidenote: Taking a “break” to learn more about testing both hardware and software analytics for audio so to eliminate my “guess work”. Found this nifty little audio software from a German company called “Musicscope” that checks the overall health of your entire music collection so that it makes it easier to spot if there are hardware issue with op amps, etc. or not! 

The best part is it’s dirt cheap 11 euros German Vat included) 

I am convinced that many audiophiles don’t really pay enough attention to issues they may be having with their music collection and are op amp rolling and make alterations that they may not be necessary! 

https://www.xivero.com/musicscope/

In regards to Opa1622 I did some digging and there are some pretty rad designs out there for stand alone headphone Amps where the Opa1622 is properly baked into the IC that have been developed by the DIYERS (who know what they are doing ie sound engineers who know the ins and outs of all audio production turned hardware engineers) and Pros that are definitely worth look into if you want to invest in some high impedience headphones for home usage and as portable amps (Caveat: the really good portable headphone amps with Opa1622 can be über expensive)


----------



## FritzS

Jan Meier use two BUF634 in BW mod in parallel for an extended Class A range.


----------



## HeyManslowdown97 (Jun 26, 2019)

In order to properly assess high impedience with large capacity loads for the Opa1622. Three things must be true high voltage proportional to the resistance. (I suspect algebra is involved to make this true). 

The high current 145mah in the Opa1622 is to offset a lost in current due to resistance. 

I’m guessing that the output Vrms on a dap must be lower than 0 and anything lower will be better to reap the benefits. 

However, this requires HIGH VOLTAGE output with resistance that allows current to pass through. I would also imagine that low ripple current is better for audio??? I have seen Film Caps used around op amps so there is certainly more than one way to get a cleaner signal. 

If you have low voltage portable dap with no dedicated headphone amplification and believe by simply lowering resistance in for being surprise when it becomes unstable. Moreover it is doubtful if you can get the full effects sans testing your results by making arbitrary guesswork choices. 

The opa1622 requires 0603 resistor (it’s in the datasheet) however, John the engineer who worked on the project stated that the larger the resistor the less power it draws. (Nothing to do with “Johnson’s” recommendation that some DIYERs like to regurgitate on threads) I’d also imagine that using the correct +ppms and % of accuracy plays a huge role in selected the best resistor for the job. 

Principles involved for high impedience

Ohm’s law states that the electrical current (I) flowing in an circuit is proportional to the voltage (V) and inversely proportional to the resistance (R). Therefore, if the voltage is increased, the current will increase provided the resistance of the circuit does not change

Which means that if resistance is high current is low and if resistance is low current is high. Then we can see that current flow around a circuit is directly proportional ( ∝ ) to voltage, ( V↑ causes I↑ ) but inversely proportional ( 1/∝ ) to resistance as, ( R↑ causes I↓ ).

Updated: DIYER: 

“Zishan DSD AK4497 version has a discrete transistor output buffer (voltage follower), so there's no point to put OPA1622 into DSD UNLESS you bridge opamp's output all the way past output resistors to the output relay inputs (or bypass discrete buffer and put OPA1622 between DIP8 opamp output and HP out, I did it on one of my DSDs).“

OY! This entire paragraph is an oxymoron. The first clause contradicts the second statement as it isn’t as simple as creating a bridge and also admitting state it’s unless-ness. You will have DC off issues if the OPA1622 isn’t properly tested for performance error when you do this. Hence, the “pop” and “crack” described in the adapted soic could be a clear sign of DC offset. It may be “ok” on floating 24-32 bit PCM files & firmware supports floating but in Dc offsets you will have issues with DSD files since it’s ONLY on one bit which already makes it unstable to begin with especially when it’s played natively with the modification. DoP may be able to meta the floating on 24-32 floating but must be baked in a sophisticated algorithm software playback! (Oh, Geez)

Digital DC Offset

In digital-land, there are two main ways DC offset can get into a signal.

More commonly, inaccuracies in the A/D converter or conversion subsystem that produce a slight output offset voltage. 

As with analog circuits, a processor that provides lots of gain (like a distortion plug-in) can turn a small amount of offset into something major.

Do not attempt this if you like to play DSD files especially on a dedicated DSD player! The 1622 isn’t intended to be used as universal buffer as well nor to be put on an adapter. If it was, TI would have made on and until then mod at your own risk! 

You MUST throughly read through this jargon (one of many). There is very little regard for making absolute statements nor zero accountability in testing this modifications for accuracy nor this claim “you bridge opamp's output all the way past output resistors to the output relay inputs (or bypass discrete buffer and put OPA1622 between DIP8 opamp output and HP out, I did it on one of my DSDs)”

DIYER: 

“John mentioned something like 3-6dB noise increase in noise above 10kHz if using this arrangement, which is negligible (and probably would still be below many opamp's noise anyway).“

Except John is talking about the Opa1622 in its true element- that is on IC circuit in a VSSON package. 

Moreover, sitting below “many” opamp noise is not ignore that fact of what it’s intended to be used for ie Headphone Amps and to drive high impedience headphones. Therefore, you can’t just lump in all or many into the topic of Op amp since Buffer Amps are designed for Buffer amps and MUX amps are designed for multichannel, etc. I would agree that some are capable of general audio usage (provided that you know what you are doing otherwise you are turn an op amp into an oscillator, lol)


----------



## Ivan TT (Jun 26, 2019)

Now, speaking about OPA1622 on a DIP8 adaptor in HP output stage again...

There's few _potential _issues indeed:
1. Ground connection
2. Power on/off click
3. Bypass caps some distance away from the supply pins

I still believe these issues are not really significant enough to discard using OPA1622 on a DIP8 adapter PCB in output stage.

Specifically, re: #1:
in response to this comment:


> Some people made an attempt in this regard but since OPA1622 requires GND pin connection for best performance it is impossible to use standard DIP-8 layout unless a compromise is made by connecting the GND pin of the OPA1622 to negative supply.


Johnc said:


> Please understand that by "compromise" we're talking about a 3-6dB increase in distortion at 10kHz, it's still quite good performance and I use DIP adapters in the lab at TI for quick results if I'm not testing for absolute best performance.
> 
> The only place I'm aware of that is selling dip adapters for OPA1622 right now is akizuki denshi in Japan ‚n‚o‚`‚P‚U‚Q‚Q‚c‚h‚o‰»ƒ‚ƒWƒ…[ƒ‹: ‘g—§ƒLƒbƒg HŒŽ“dŽq’Ê¤ “dŽq•”•i ƒlƒbƒg’Ê”Ì but I am not aware if they ship internationally.
> 
> Maybe I need to start a side business


I note that cheap ebay version creates a virtual ground by splitting rails, and that ground pin is used for enable and a compensation capacitor, so as long as the rails are not totally out of whack I doubt performance will take even a small hit that it does when the ground pin is connected to negative supply.
I also note that Johnc has no issues with PCB DIP adapter 
	

	
	
		
		

		
		
	


	




 and while it does not provide "absolute best performance", I agree that it is very, very good (and actually better compared to many general use or otherwise repurposed for HP output stage opamps).

#2 is tricky as it is possible to easily create a voltage divider for enable pin so that it is on only after rails ramped up completely (I tried that), but even using it properly (say using delayed GPIO signal and I tried that too) still produces low-level pop (this has been noted on diyaudio as well), which is still well below what some other opamps produce anyway so no real issue here IMO.

#3 bypass caps are mounted on the PCB and while the ground is virtual, it is not uncommon to bypass power supply by hooking up a x2 value cap between rails, but having them on PCB is still far better than not having them at all or some distance away.

Finally, opamps have never been designed to work as HP drivers (so ANY opamp driving headphones directly is not used for intended purpose, unless it has been specifically designed for this purpose, but only few were e.g. OPA1622, TPA1620 I actually struggle to come up with any other examples here), and the way their pins are arranged is not very good for low noise/distortion performance (one of the reasons for OPA1622 form-factor by the way). So from my point of view (I'd like to believe that it is a well informed one too) retrofitting ANY device that offers DIP8 socket for opamp as the output stage (aka CMOY) with DIP8 socketed OPA1622 is a no-brainer, and I am not aware of any characteristic that matters where OPA1622 is not superior to any other opamp (or at least on par), even when using DIP8 adaptor (well, except maybe output impedance as there are some opamps that offer lower Z and are still capable of driving capacitive loads e.g. AD826 if memory serves me right here but it does not sound as good unfortunately).


Spoiler: Disclaimer



I don't get a cut from OPA1622 on DIP8 PCB ebay sellers


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## Rroff (Jun 26, 2019)

Ivan TT said:


> Finally, opamps have never been designed to work as HP drivers (so ANY opamp driving headphones directly is not used for intended purpose, unless it has been specifically designed for this purpose, but only few were e.g. OPA1622, TPA1620 I actually struggle to come up with any other examples here)



Some of the JRC/NJM opamps are designed with audio use including driving headphones in mind, same for the TI variant of the RC4580. AD8397 and a couple more like that are designed for the kind of loads that you'd get from headphones as part of their audio considerations. There are 2-3 more that I can't name off the top of my head that are designed with driving 16-600ohm headphone model loads.

It is true of a lot of opamps though - especially some can as I've mentioned have implementations designed for things like the demands of DSL drivers that are sub-optimal for headphone use.


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## Ivan TT (Jun 26, 2019)

Rroff said:


> Some of the JRC/NJM opamps are designed with audio use including driving headphones in mind, same for the TI variant of the RC4580. AD8397 and a couple more like that are designed for the kind of loads that you'd get from headphones as part of their audio considerations. There are 2-3 more that I can't name off the top of my head that are designed with driving 16-600ohm headphone model loads.
> 
> It is true of a lot of opamps though - especially some can as I've mentioned have implementations designed for things like the demands of DSL drivers that are sub-optimal for headphone use.


Precisely.

Generally it’s either repurposing ADSL drivers or opamps designed for LCD monitors (e.g. LM7332 which is actually quite good and easy to implement, especially compared to AD8397) and these are a bit better at driving capacitive loads too.

But among opamps dedicated specifically to driving HPs OPA1622 is the newest and addresses issues older designs had (e.g. stability issues of TPA1620 requiring use of output resistors).

Well, there’s also INA1620 which is even better than 1622 (EMI/RFI hardened input stage, integrated high precision resistors), but it’s unlikely to appear on DIP8 adapter (I have it on a bigger DIP PCB but did not have time to test it yet).


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## HeyManslowdown97 (Jun 26, 2019)

Rroff said:


> Some of the JRC/NJM opamps are designed with audio use including driving headphones in mind, same for the TI variant of the RC4580. AD8397 and a couple more like that are designed for the kind of loads that you'd get from headphones as part of their audio considerations. There are 2-3 more that I can't name off the top of my head that are designed with driving 16-600ohm headphone model loads.



The JRC/NJM engineers were some bada** Audio op amp engineers with all encompassing op amps that hold merit to present day!

Funny thing all this talk and research made me really wanna get a killer portable headphone amp designed to drive low impedience headphones. 

Anyone have an recommendation Holla at ya boy!

Oh, is there a headphone with an amp build inside of it that’s powered by rechargeable battery! It would be pretttty rad if a company would make it with a op amp like the 1622. 

I don’t know...Grados is family owned a located in BK May have to take a trip and present my idea to say what they say haha


----------



## Rroff

Ivan TT said:


> Precisely.
> 
> Generally it’s either repurposing ADSL drivers or opamps designed for LCD monitors (e.g. LM7332 which is actually quite good and easy to implement, especially compared to AD8397) and these are a bit better at driving capacitive loads too.
> 
> ...



Analog Devices have recently pushed out some new opamps in the LTC range I think that are designed with driving headphones in mind but I've not kept upto date on developments like that.


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## HeyManslowdown97 (Jun 26, 2019)

Rroff said:


> Analog Devices have recently pushed out some new opamps in the LTC range I think that are designed with driving headphones in mind but I've not kept upto date on developments like that.



Well over my head but there is also circuitry that can push large capacity loads. 

https://www.allaboutcircuits.com/te...-drive-large-capacitive-loads-op-amp-circuit/

I’m think with a combo of high current op amps and higher voltage along with volume control op amp you get there too. The biggest challenge is how to keep it stable!  

“The PGA2311 device is a high-performance, stereo audio volume control designed for professional and high-end consumer audio systems. The PGA2311 uses an internal high-performance operational amplifier to yield low noise and distortion. The PGA2311 also provides the capability to drive 660-Ω loads directly without buffering. The 3-wire serial control interface allows for connection to a wide variety of host controllers, in addition to support for daisy-chaining of multiple PGA2311 devices.”

The PGA2311 is a smash hit on arrow.com and operates only a 5 volts. It’s in their top searched. It’s a 16pin soic op amp that can function on a dap volume control and gain. 

That said Opa1622 is a pretty rad innovation for its package and intended using in a IC for headphone amplifiers


----------



## HeyManslowdown97

Rroff said:


> Analog Devices have recently pushed out some new opamps in the LTC range I think that are designed with driving headphones in mind but I've not kept upto date on developments like that.



Sorry for the rapid Double Post but doesn’t 600 Ohms even sound like? Do I get lost in an abyss of sound?


----------



## LaughMoreDaily

The OPA2210 has come out. It's an upgrade to the 2209. I found it on ebay.


----------



## motorwayne

LaughMoreDaily said:


> The OPA2210 has come out. It's an upgrade to the 2209. I found it on ebay.



How different are they to the OPA2111? I have the HA steel version version in my Titanium HD soundcard.


----------



## LaughMoreDaily

motorwayne said:


> How different are they to the OPA2111? I have the HA steel version version in my Titanium HD soundcard.


Wrong person to ask.  I haven't heard all three of those.


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## Rroff (Jul 8, 2019)

motorwayne said:


> How different are they to the OPA2111? I have the HA steel version version in my Titanium HD soundcard.



On paper, whether it is noticeable to the ear or not is another matter, the 2210 is much improved for things like noise, though the 2111 still has some tricks up its sleeve in that context. There are a fair few differences in "architecture" approach as well. I've never sat down and tested them side by side but from what I recall the 2111 is quite bright compared to the 2209 which tends to sit in a half-way point between the 1612 and 2228 having a more 2228 like organic sound than the 1612 but not the touch of warmth that gives a richer sound to the 2228.

Shame they didn't put a bit more design focus into the 2210 in driving headphones with a bit of attention to those kind of loads and slightly extend the current output a bit as otherwise it looks excellent for that use - they do look like a solid choice on paper for the IV stage though.


----------



## Mad Max

LaughMoreDaily said:


> The OPA2210 has come out. It's an upgrade to the 2209. I found it on ebay.


I got the chip a few weeks ago, not yet tested.


----------



## LaughMoreDaily

Has anyone made a top 10, 15, 20, etc. Opamp list yet?


----------



## CoiL

LaughMoreDaily said:


> Has anyone made a top 10, 15, 20, etc. Opamp list yet?


That could be made only in/with one certain gear as opamps act little differently in different implementations/PCB designs etc.


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## Rroff (Jul 13, 2019)

Also depends what you use to rank the opamps - impressions by ear are always going to be subjective and the impression highly varied by the design they are used in as CoiL says. There have been various attempts to rank them by on paper parameters like voltage noise (such as https://www.cycfi.com/projects/six-pack/op-amp-shootout/ ), etc. but again that is going to depend a lot on application and doesn't necessarily translate into how subjectively people rate them for audio "appeal" sonically.

Most of the attempts I've seen so far are quite out of date and missing many of the newer or more recently "discovered" as being usable for audio opamps.

One of the problems is on paper and even measured performance in a given standard test scenario doesn't necessarily match upto to performance in a specific design or use case - similar problem with voltage regulators which in many cases actually are in a simplified manner similar to opamps (people have even misused the error amplifier in a voltage regulator as a crude audio amplifier) - you might find in a specific design despite one having better noise performance on paper in the datasheet in your actual use case another has better actual performance in the conditions specific to your application despite being worse in the datasheet, etc.


----------



## LaughMoreDaily

Rroff said:


> Also depends what you use to rank the opamps - impressions by ear are always going to be subjective and the impression highly varied by the design they are used in as CoiL says.


I think you are thinking too much. I was just wondering what peoples favourites are.


----------



## CoiL

LaughMoreDaily said:


> I was just wondering what peoples favourites are.


This is different question! 

My current favourites are OPA2228 and OPA1692.


----------



## Rroff

LaughMoreDaily said:


> I think you are thinking too much. I was just wondering what peoples favourites are.



Which is always going to depend on a degree of subjective and objective assessment factors.

In no particular order - though the AD8066 tends to take top place for me the ones I use the most which would be favoured over others:

AD8066
OPA2228
OPA2209
OPA1612/2211
OPA1692

I also use OPA2227, RC4580, NJM4556, LM4562 and LMH6643 quite a bit.


----------



## omegaorgun

CoiL said:


> This is different question!
> 
> My current favourites are OPA2228 and OPA1692.



Just picked up 2 1692's with adapters already on. Gonna be interesting when popped into my new Chinese super amp.

Anyone been able to get the new 1656?


----------



## FritzS

What did you think about *OPA209*? What ist your experience?
And comparing OPA209 with AD797?
https://www.ti.com/product/OPA209


----------



## Mad Max

209 and 797 are very different beasts, though I have not yet tried 209 as a buffer.
797 hasn't been all that great in my gear, it seems to not be a "blind-roll" friendly chip, so you'll be very dependent on luck for best results. Or become an engineer.


----------



## Baten

FireLion said:


> Just picked up 2 1692's with adapters already on. Gonna be interesting when popped into my new Chinese super amp.
> 
> Anyone been able to get the new 1656?




I want to try the 1656 it looks insane on paper. Does it also need adapter like the 1692 as drop in replacement in the weiliang amp(that's your chinese amp right?)
If so, what kind of adapter? 

cheers


----------



## omegaorgun

Baten said:


> I want to try the 1656 it looks insane on paper. Does it also need adapter like the 1692 as drop in replacement in the weiliang amp(that's your chinese amp right?)
> If so, what kind of adapter?
> 
> cheers



It look like it needs an adapter.. might be able to but I might hand it over to my amp making friend.


----------



## Baten

FireLion said:


> It look like it needs an adapter.. might be able to but I might hand it over to my amp making friend.


Let us know, I would love to put the new 1656 in a cheap amp lol


----------



## omegaorgun

Baten said:


> Let us know, I would love to put the new 1656 in a cheap amp lol



My cheap amp has been smoking $400-500 amps with nicer opamps.

US $18.24  8%OFF | Pure class A Audio Discrete Component Operational Amplifier HiFi AUDIENCE Preamplifier Op Amp Chip Upgrade ADC LRC DAC
https://s.click.aliexpress.com/e/hoZ1PcU


----------



## Baten

FireLion said:


> My cheap amp has been smoking $400-500 amps with nicer opamps.


I think you linked an op-amp instead  can you edit post?


----------



## FritzS

Mad Max said:


> 209 and 797 are very different beasts, though I have not yet tried 209 as a buffer.
> 797 hasn't been all that great in my gear, it seems to not be a "blind-roll" friendly chip, so you'll be very dependent on luck for best results. Or become an engineer.


I don't think to use them as buffer, but only as pre-stage and a buffer after - for using as headphone amp.

PS: I know 797 is a “diva“. But works good in my WNA MKII HA (without recommend small bypass caps) - that was designed for another “diva“ LM6171. Another HA use 209 and BUF634.


----------



## omegaorgun

Baten said:


> I think you linked an op-amp instead  can you edit post?



US $93.99 | WEILIANG AUDIO E600 fully balanced dual core low distortion headphone amplifier
https://s.click.aliexpress.com/e/bQtSVJyy

And my friends custom 2520's. I hope he an make me a DIP version as it has THX levels of clarity. In fact I had a Khadas and with a few amps if you maxed the volume with no music you could here distorted crackling but on this amp there was silence.


----------



## Baten

FireLion said:


> US $93.99 | WEILIANG AUDIO E600 fully balanced dual core low distortion headphone amplifier
> https://s.click.aliexpress.com/e/bQtSVJyy
> 
> And my friends custom 2520's. I hope he an make me a DIP version as it has THX levels of clarity. In fact I had a Khadas and with a few amps if you maxed the volume with no music you could here distorted crackling but on this amp there was silence.



Nice! How does it compare to the chinese amp


----------



## omegaorgun

Baten said:


> Nice! How does it compare to the chinese amp



More clarity with less power, it's a unique amp that I can only compare to the THX 788 I had for dynamics. This Chinese amp to my ears is louder than a Jotunheim balanced even on SE and is not far behind, I think with the right opamp it could be as good.


----------



## Rroff (Jul 18, 2019)

EDIT: Ignore.


----------



## LaughMoreDaily

Baten said:


> I think you linked an op-amp instead  can you edit post?


His link wouldn't work for me on my mobile.


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## omegaorgun (Jul 19, 2019)

OPA2604's are actually very nice, I might prefer them to the 4562 in my current setup, Have 2132's here. OAP1692's on the way. 

Edit: OPA2132's sound very good too.


----------



## Rroff

FireLion said:


> OPA2132's sound very good too.



I have a hard time liking the OPA2132 or 2134 - they are decently transparent and easy to work with but somehow there is for want of a better way to put it a lack of passion when they are prominent in the audio chain - what I've said before it is like someone playing the same tune after the 1000th time - accurate but lacking the sparkle of the first few times.

OPA2604s I've not spent much time with - I've a soundcard somewhere that uses them but not tried them in my amps.


----------



## omegaorgun (Jul 19, 2019)

Rroff said:


> I have a hard time liking the OPA2132 or 2134 - they are decently transparent and easy to work with but somehow there is for want of a better way to put it a lack of passion when they are prominent in the audio chain - what I've said before it is like someone playing the same tune after the 1000th time - accurate but lacking the sparkle of the first few times.
> 
> OPA2604s I've not spent much time with - I've a soundcard somewhere that uses them but not tried them in my amps.



The 2604 is a bit sharper and more technical than  the 2132 which I think maybe had a little bloated bass or something going on with it. Initially it sounded good.

4562 is joint first or strong second and is a little less sharp but pretty enjoyable.

I am looking forward to the 1692's but these have me interested.

SH03 Component Operational Amplifier Preamplifier Single Double Op Amp
https://s.click.aliexpress.com/e/b6h0oxEu


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## Rroff

FireLion said:


> I think maybe had a little bloated bass or something going on with it.



That is the supposed Burr-Brown sound - a touch warm and fairly relaxed but tends to make the bass a little bloated. Some like it some don't. Personally I consider the OPA2227 a better 2132 and the OPA2228 better again as it has a certain "something" the 213x/2227 lacks.


----------



## Mad Max

Never going to like the mids on 2134 and 2132.  Yuck.
Bass bloat with TI chips?
I doubt it is inherent to most of TI's chips.


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## Rroff

Mad Max said:


> Never going to like the mids on 2134 and 2132.  Yuck.
> Bass bloat with TI chips?
> I doubt it is inherent to most of TI's chips.



On a lot of more recent ICs "Burr-Brown" seems to be used more as a marketing term for having a certain minimum audio standard - TI seems to want to keep the name alive in respect for its pioneering work. On older chips (including the 213x and 222x, etc.) it was usually synonymous with a certain type of sound.


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## omegaorgun

I'm gonna get the 1656 samples next week and have my surface mounting friend get them on dip adapters.

Has anyone tried a 1692?


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## Rroff (Jul 21, 2019)

Yeah I've used the 1692 in a couple of amps. I like - it just sounds "right" - no problem areas/concerns I've noticed, neutral with good articulation, good separation but not "open and airy" - it won't blow you away with its "musicality" or tonality or anything as some ascribe to some opamps but it is basically just a well balanced opamp suited to a wide range of applications.

I think there might be a little bit of LM4562 like harshness in the mid-range but only a little bit.


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## Baten

FireLion said:


> I'm gonna get the 1656 samples next week and have my surface mounting friend get them on dip adapters.



You can simply mount these on dip-8 adapters? Interesting


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## HeyManslowdown97 (Jul 23, 2019)

FireLion said:


> I'm gonna get the 1656 samples next week and have my surface mounting friend get them on dip adapters.



I have the Opa1656 and it’s fantastic! I’m dying to try the Opa1692 as I’ve heard it’s nice sounding and more importantly great in the voltage stage of your rig. 

Just learned how to fix my digital files to play at optimal peaks sans binary errors so now looking forward to testing out different op amps and fixing hardware issues properly. 

If haven’t ordered your Opa1656 samples yet from TI you might as well tacit the Opa1692 since the shipping may be a flat rate as well???


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## omegaorgun

HeyManslowdown97 said:


> I have the Opa1656 and it’s fantastic! I’m dying to try the Opa1692 as I’ve heard it’s nice sounding and more importantly great in the voltage stage of your rig.
> 
> Just learned how to fix my digital files to play at optimal peaks sans binary errors so now looking forward to testing out different op amps and fixing hardware issues properly.
> 
> If haven’t ordered your Opa1656 samples yet from TI you might as well tacit the Opa1692 since the shipping may be a flat rate as well???



I got two already together on a dip from Hungary, solder work looks solid. So what IC are burson using on the v5i? my friend said it looked like they are forcing it into class-A.

Seller eBay page.


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## Mad Max

OPA1692's unusually low quiescent(?) current means it is "battery-friendlier" than most other opamps, right?


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## Baten

@FireLion be sure to compare Opa1656 and Opa1656 when you have both


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## Rroff

Mad Max said:


> OPA1692's unusually low quiescent(?) current means it is "battery-friendlier" than most other opamps, right?



Yes compared to other opamps of a similar quality - there are other opamps that have lower current but not necessarily a good choice for audio - the OPA1692 is designed for portable audio (and USB).


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## Mad Max

I tend to steer clear of opamps not specified for audio most of the time.


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## Headmate (Jul 24, 2019)

Here is my take on XD05 and V5i pairing: What others found before my post is true indeed. XD05 shines with the V5i, went a great deal in removing the veil and 'darkness'.




V5i brought about a drastic change by controlling the bass better, making the hit/slam quicker, less bloomy, opening up the mids and extending the highs which the XD05 badly needs. Staging and imaging are phenomenal. Level of transparency and detail retrieval are better compared to stock OPA1612 and few others I tried from LME/AD/OPA series. Good op-amps try not to add their own character to the sound, and the V5i sticks to that. Slight flavor is heard depending upon the circuit used, but I feel that’s expected and can’t be prevented.



Pulled off the top metal cover to make space for capacitors. V5i is perhaps one of very few opamps today that focuses on soundstage, and the staging is such that it feels well layered and details emanating from each layer can be heard with an analytical headphone. Nice advantage of V5i over all other discrete op-amps: It fits in about any DIP8 socket, regardless the case size. I would recommend the V5i if you like your amplifier/DAC but want to make it sound cleaner, clearer: and the change V5i brings out is incredible.



Don’t mind me if I sound enthusiastic, Burson is kind of my favorite audio brand given their sound engineering and design philosophy focusing on soundstage & transparency. Kudos Team Burson!


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## HeyManslowdown97 (Jul 25, 2019)

Crazy Concept/Experiment. 

Has anyone ever tried/attempted putting two different op amps in a lpf (or in another particular stage??) to be used in two isolated different (stereo) channels? 

Would be pretty rad to get an “aggregated” sound between two contracting op amps that’s characteristics that compliment themselves as a pair. 

The only problem I can spectacle happening is: oscillating and temple/pitch issues??

*note I’m not talking about putting single or double amps on an adapter. I’m talking another two separate amps that would operate independently on two different channels.


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## Rroff (Jul 25, 2019)

Do you mean something like having one opamp handle bass and another mid-range and treble on the same channel or having completely separate opamps on opposite left and right channels?

The first would probably have some pretty funky issues around the frequency cut-off of the filter but might produce interesting results if accuracy isn't a goal. You can stop them fighting each other by sticking a 1-2ohm (occasionally might need slightly higher for some opamps) resistor on the output of each where they combine.

The other there are various takes on like the pseudo-balanced amplifier someone on here built - I also separately built my own variant of it using dual isolated power supplies, etc.


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## omegaorgun (Jul 27, 2019)

I accidentally had two different op amps in and I think each one was set up for left and right. Didn't notice until I went looking for an opamp to swap.
I had 2x 2314's in and they were warm, not bad at all. I found OPA2604 to have more clarity.

I am still waiting on the 1692, I am thinking of getting 4 of the old 49710's and putting them on a dual adapter. Heard them in a whammy that takes 2520, it had 4 and it was super holographic.

There is a whammy on the right the other one I mentioned is not pictured that has the 49710's. The smaller amp on the left is amazing. I am trying to get my friend to get it on to a dip. It's a very picky op amp but it might be worth a shot.

For those not familiar with the 2520 types, the entire green daughter board is actually the op amp. The 990C+  one that is made by a company and my audio freind who makes these amps knows him I believe.


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## CoiL

FireLion said:


> Has anyone tried a 1692?


I`m using OPA1692IDR (DAC differential opamp) + OPA2228PA (HO amp) and it sounds quite marvelous in my Aune T1.
Stopped trying other opamps after this pairing (using with Siemens E88CC goldpin as tube buffer)


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## ashleydoormat

So I'm completely new to op amp rolling. I just got two Muses op amps from Amazon two days ago and I'm thinking they might be fake? I only listened to the Muses01 op amp since yesterday and it isn't that great comparing to what I currently have (OPA2604AP) in my chi-fi 6j1 tube headphone amp (the amp came with NE5532P which is probably fake as there were distortions all over the place so I replaced that with a OPA2604AP I got from a trusted dealer). The Muses01 sounds a bit incoherent in my setup but not as bad as the original op amp. I'm wondering if it the problem is my setup or the op amp?


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## raoultrifan

Hard to say from the pics, but look legit. However, try to bend the legs easily...they should bend 3 times more easy than a regular opamp, due to the added copper inside. Of course, legs will also break 3 times faster, so pls take care.


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## HeyManslowdown97 (Jul 27, 2019)

Rroff said:


> Do you mean something like having one opamp handle bass and another mid-range and treble on the same channel or having completely separate opamps on opposite left and right channels?
> 
> The first would probably have some pretty funky issues around the frequency cut-off of the filter but might produce interesting results if accuracy isn't a goal. You can stop them fighting each other by sticking a 1-2ohm (occasionally might need slightly higher for some opamps) resistor on the output of each where they combine.
> 
> The other there are various takes on like the pseudo-balanced amplifier someone on here built - I also separately built my own variant of it using dual isolated power supplies, etc.



Wow! That’s impressive that someone here built two isolated powered channels. 

Pseudo-balanced idea seems interesting and maybe perfected with the right software algorithms that are custom made per channel. That would require some hardcore software engineering skills. 

The pseudo surround sounds I’ve encountered on the software side all sound artificial but there are some that get it right like Cowon. 

... basically wanted to put a opa2228 on one channel and AD8620 on the another. (Left + Right) 

Off the top of my head the only thing I can see as a logical problem would be that if the op amps aren’t close in specs there could be a time issue with latency. However, as a byproduct it could be a nice experiment to A/B Test in each ear which op amp would sound better?? 

As long as nothing hardware-wise is being compromised, it seems like a harmless way to experiment but I’m certainly not sure to say so with absolute certainty to all.  

I would imagine that you’d have put two op amps that are of = Class A, B, etc. on separate stereo channels in the same stage. (Would imagine it sounded funky otherwise unless it’s so minimal that your ears don’t detect any difference) 

Many modern discrete op amps don’t draw a lot of current so if the range of both different op amps are of = value energy consumption it should be a problem. 

As far the “warm” or “bright”, etc it is my belief that this is determined by how the op amp feature or highlight certain frequencies and how they tuned. This is how sound engineers mix audio tracks. 

All things equal a great firmware that  integrate with a high performance op amp with a wide bandwidth will sound ANYWAY you want. Lots of Diyers find this difficult to accept since they only tend to focus to the “Analog” part of the Digital-to-Analog converters. 

Lots of sound issues are really a factor of how well your clocks are, how the upsampling and if there errors in the binary info of the files.


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## Rroff

If you have an amp that is designed with a different opamp for left and right (it is normally the case for 2x single channel opamps amps) not a problem to do that at all - people have done it in the past to do testing.


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## HeyManslowdown97 (Jul 28, 2019)

Rroff said:


> If you have an amp that is designed with a different opamp for left and right (it is normally the case for 2x single channel opamps amps) not a problem to do that at all - people have done it in the past to do testing.



(It had to be said) Yea you definitely don’t wanna do it with single amps combined on an double adapter to make them dual amps per channel unless you wanna an unsafe pyrotechnic show. Haha.


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## Rroff

HeyManslowdown97 said:


> (It had to be said) Yea you definitely don’t wanna do it with single amps combined on an double adapter to make them dual amps per channel unless you wanna an unsafe pyrotechnic show. Haha.



Aslong as you don't connect their outputs directly together and instead each has a low value resistor on the output they shouldn't fight each other - though you'd be best off scoping to be sure.


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## HeyManslowdown97 (Jul 28, 2019)

Rroff said:


> Aslong as you don't connect their outputs directly together and instead each has a low value resistor on the output they shouldn't fight each other - though you'd be best off scoping to be sure.



Haha, it’s like I always say If you didn’t burn the house down than anything is possible! 

Honestly one of the ONLY things I’d like to fully learn is how to evaluate resistors on DAC but it’s frickin’ algebra and sh** and get the most “controlled” sound signal sans compressing the sound signal. I feel the same way about film caps. The op amps are pretty solid that even a idiot like me can solder that crap on with no problem (Most of the time). Haha


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## ashleydoormat (Aug 3, 2019)

Nevermind I returned both the Muses01 and Muses03. The packaging doesn't instill any confidence that they're genuine JRC products. Besides I also got a Sparkos SS3602 op amp and it's been working beautifully in my cheapo chi fi amp!


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## FritzS

ashleydoormat said:


> Nevermind I returned both the Muses01 and Muses03. The packaging doesn't instill any confidence that they're genuine JRC products. Besides I also got a Sparkos SS3602 op amp and it's been working beautifully in my cheapo chi fi amp!



Please tell me more about your cheapo chi fi amp.


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## ashleydoormat

FritzS said:


> Please tell me more about your cheapo chi fi amp.


It's a pretty basic 6j1 tube amp available on Amazon and Aliexpress for about $40. It originally came with NE5532 and tiny caps which sounded congested and incoherent. Then I changed to OPA2604 and also changed out some of the caps to improve the bass and soundstage (put them under the board as there is no room on top). The new SS3602 opens up the amp some more. I'm new to diy and op amp so it's a cheap way to practice and an excuse to make use of my Mullard tubes


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## omegaorgun (Aug 6, 2019)

Had my amp making friend who is now working on a balanced version of his KAD amp, had him throw these OPA1656's on some adapters for me. Very clean sound, can't find any faults with it, bass extends very deep and balanced throughout the rest of the FR. Might be the cleanest I have heard.

Have two Chinese opamps on there way for a big review I am going to put together.
Pictured with V5I-D's, OPA2134 and a HDAM Full Discrete which is two singles on an adapter.


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## Baten

FireLion said:


> Had my amp making friend who is now working on a balanced version of his KAD amp, can't wait throw these OPA1656's on some adapters for me. Very clean sound, can't find any faults with it, bass extends very deep and balanced throughout the rest of the FR. Might be the cleanest I have heard.



Damn! Jealous


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## omegaorgun

Baten said:


> Damn! Jealous



edited, I meant he did throw the 1656's on for me in the lower right.


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## omegaorgun (Aug 9, 2019)

The 1656's are pretty nice but the v5i-d's make a compelling case as to why they should remain in the amplifier. Burson are spacious with nice imaging. Not sibilant but good detail, It has a smooth edge so to speak overall a very enjoyable opamp and it looks pimpin.

1656 is equally as good being the latest and greatest and look at them on there little matching black boards made for me courtesy of KAD designs. It's a bit sharper, Burson might sound slightly more weighty but both are worth having.

Whilst I am on it the HPA-3B is well above it's HPA-2C counterpart for quality, I feel the cirrus DAC is not the best and if they had and ESS or AKM in there it would help.


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## HeyManslowdown97 (Aug 12, 2019)

Finally had a chance to roll some Opa1612 and gotta say it's one of the best op amps ever made imo. I get the criticism of it sound ”artificial” but that darn thing so fast with detail; it’s captures EVERYTHING and is best all around op amp I’ve tried! 

The Opa1692 is amazing for low voltage application and nice sounding too. 

I’m rocking 2x Opa2209 in the input stage and been rolling with LT1358, AD8620, Opa1612 and Opa1692! 

I have the AD8022 but I need an adapter for the sop (the smaller package soic) and haven’t soldered the AD8066 to try it out with the Opa2209. 

The Opa2209 so sweet it’s got a limitation but so nice with acoustic music and vocals (wow!) so natural! Pairing it with AD8620 (also excellent) brings out the both  signature AD sound (the bass is punchy, right and doesn’t influence the tremble in with  murkiness; there’s clarity) with the Burr-Brown Laid back sound with warmth and just tremble bliss. 

The AD8620 is a bit sharp in the tremble which causes it have some harshness that many have rightfully criticized it for but I’m sure can be “fixed” with the right adjustments on the DAC (resistance, caps, etc). It does have more detail that the opa2209 is lacking. The two combined make for intimate soundstage reserve for some warm jazz or acoustic music. When paired they do however lack a wider soundstage and depth compared to other pairings I’ve tried with this experimentation. 

The Opa2209 + Opa1692 is just nice. The op amps compliment themselves so perfectly. But so far the best combo with the Opa2209 is with Opa1612. They work really well together. Of course the burr brown laid back sound lacks the AD “just right” bass punchiness and I’m hoping to fine AD equivalent to Opa1612. I research and what I got is the ADA4004-2 so I’m hoping that’s one AD “response” to the Opa1612 to get both sound aesthetics playing in my ears with perfect equilibrium! 

In my experience with Op Amp Rolling it’s all about finding the right op for the right situation and application. Then it’s a question of the perfect differential between different op amps in the right stages! I have found that often the op amps with contracting sound qualities are the perfect pairing if they are balance that compliment each other rather than trying to compete for dominance! There’s also no such thing as the perfect combo or holy grail of op amp(s) for every music style but ones that work better than others.


----------



## carlmart

At the end of what are you using all this? A DAC? Which one?


----------



## Mad Max

ADA4004 is a rather "polite" opamp, If I recall correctly. I didn't really like it much.


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## HeyManslowdown97 (Aug 14, 2019)

carlmart said:


> At the end of what are you using all this? A DAC? Which one?



DAC really doesn’t matter; it’s one I like so it’s a moot point to reference it. All I can say as an importable fact is that it’s a portable one so low volts/current op amps work best in this application to save on battery life especially if theres a semiconductor cpu(s) involved!

Assuming... Everyone’s overall goal on this thread is to reference op amps and their characters, stages, etc, I was talking about combos of Op amps that play nice together. 

Would like to try and experiment with some Opa1612 in combination with AD8397 as I believe based on what I’ve read their contrasting traits would be an interesting experience sonically!


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## omegaorgun

HeyManslowdown97 said:


> DAC really doesn’t matter; it’s one I like so it’s a moot point to reference it. All I can say as an importable fact is that it’s a portable one so low volts/current op amps work best in this application to save on battery life especially if theres a semiconductor cpu(s) involved!
> 
> Assuming... Everyone’s overall goal on this thread is to reference op amps and their characters, stages, etc, I was talking about combos of Op amps that play nice together.
> 
> Would like to try and experiment with some Opa1612 in combination with AD8397 as I believe based on what I’ve read their contrasting traits would be an interesting experience sonically!



When you say a DAC doesn't matter what do you mean? I think every CS4398 DAC I have tried sounds like poop including the mecca of ASR the D30, in fact the cheaper D10 is a better and cleaner sounding unit. I find the ESS very clear and transparent the AKM's a little bit more silky in it's presentation. (disclaimer: to my ears)


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## Mad Max (Aug 15, 2019)

I haven't had any bad experience with Cirrus Logic DACs myself.  The only DACs that I've really disliked are just those ESS DACs.  Disgusting sound.
I still prefer BB, AKM, and ADI, which are still common.  AKM sure is popular these days.
I had not tried PCM1795 until the Teac P90 and FiiO E18.  Wow, what beautiful sound.

Also, forgot to recommend ADA4001 over ADA4004.  4001 is uber transparent, more than most opamps.  Specified for mic preamps, and I can hear why it would rock hard in such, especially in recording gear.


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## HeyManslowdown97 (Aug 15, 2019)

FireLion said:


> When you say a DAC doesn't matter what do you mean? I think every CS4398 DAC I have tried sounds like poop including the mecca of ASR the D30, in fact the cheaper D10 is a better and cleaner sounding unit. I find the ESS very clear and transparent the AKM's a little bit more silky in it's presentation. (disclaimer: to my ears)



I’m not saying a DAC is irrelevant what I am saying is we all have different taste and priorities/personal preferences for sound so I just put my opinions and thoughts on the thread in regards to op amp rolling  & didn’t feel the need to talk about my particular portable music player because it wasn’t relevant for the discussion and only creates a  diversion. 

Obviously, the way a DAC is tuned and what chip it has impacts the sound. What I like about the ESS chips is that they are EXTREMELY power punchy sounding and the bass is amazing but I prefer the AKM sound and the Sony neutral sound but I won’t dismiss ESS “sound” since the “magic” really comes from the circuitry. (IMO) 

 I just got the new Nw-55 Walkman and it’s a great daily driver for on-the-go. You can’t op amp roll with it but it’s a great performer even in “stock mode.” 

D10 is great. I love Topping such quality DACs. I wanted to get one portable headphone amp but it didn’t have balanced out for 2.5m. Topping are also DIY friendly with Op Amp Rolling. The great thing about op amp rolling is that when you sick of certain sound you can mix it up. I like to mix it up every once and while.


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## UrsaUrsulas

Hi guys! I have being using the Burson V6 Vivid 2years with my beloved Sound Blaster X7!!! And if i put the default opas back they suck in all areas!  and the highs feel uncontrolled like the bass region only middle section is allmust same level in my opinion in games i have noticed with HD800 that pinpoint and distant accuracy is supah versus stocks! And now i just recently buyed new Sound BlasterX AE-9 but i tryed to force to fit those big V6 and the one pin broked and was Dual "Darn!!" this is the reason to post this because maybe sombody read this with intention to bye new AE-9 and quality of V6 Vivid is honestly superb! Damn have to get some money and buy one new V6 V dual to old X7 and 2x V5i single and 2x V5i dual to new Sound BlasterX AE-9! I hope this really help even one person! Peace and enjoy the music! <3


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## raoultrifan

Did you broke V6's pin? Is the DIP8 still attached to the V6

You may want to upload a picture with with the broken pin.


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## UrsaUrsulas (Aug 21, 2019)

raoultrifan said:


> Did you broke V6's pin? Is the DIP8 still attached to the V6
> 
> You may want to upload a picture with with the broken pin.


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## CoiL (Aug 21, 2019)

That`s no problem imho. Just needs some soldering and gentle push into DIP-8 socket (make sure you have HQ socket that is with accurate pin placement).
I also broke one pin with my V5i-D and for convinience, just used tiny piece of hq wire with soldering - works like charm 
Harder choice is to remove old pins-socket completely and install new one.
Anyway, no need for getting new opamp IMHO as it is working perfectly.

BTW, I think Burson is using crappy male pins adapter, material on those pins is so fragile.
Proper pins with good plated copper shouldn`t brake so easily, imho.


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## UrsaUrsulas

CoiL said:


> That`s no problem imho. Just needs some soldering and gentle push into DIP-8 socket (make sure you have HQ socket that is with accurate pin placement).
> I also broke one pin with my V5i-D and for convinience, just used tiny piece of hq wire with soldering - works like charm
> Harder choice is to remove old pins-socket completely and install new one.
> Anyway, no need for getting new opamp IMHO as it is working perfectly.
> ...




Thanks Coil from the very good advice to help me!!!!! Thanks again and i hope you have a great day!!!! <3  
ps. yes it srsly broked instantly for the first try with the new card!


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## raoultrifan

I guess with 5-10EUR any GSM service should help you out.

The legs are made from a highly conductive copper compound for better conductivity and zero tolerance to corrosion and oxidation. You guys need to see how easy the pins of MUSES01/02 brake...


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## UrsaUrsulas

raoultrifan said:


> I guess with 5-10EUR any GSM service should help you out.
> 
> The legs are made from a highly conductive copper compound for better conductivity and zero tolerance to corrosion and oxidation. You guys need to see how easy the pins of MUSES01/02 brake...



Yes indeed that was too nice idea and the shop is so close than im going there! Il be back! "report then"


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## HeyManslowdown97 (Aug 28, 2019)

Hey All! 

I would like to do some more dual op amp rolling with a few priorities in mind: 1. Low power 2. Ultra low noise 3. Ultra low distortion 4. Wide voltage range 

I am looking for something in the same class as the the Opa1692, lm4562, NE5532, NE5534, etc however I want to experiment with different companies/sounds like NJR, AD and Maxim, etc since I mostly experienced in TI ones (which are great!!!)

I would like the best low power high performance ratio with a nice soundstage and dynamic range. Thanks!


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## CoiL

OPA2228


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## omegaorgun (Aug 30, 2019)

Here are some old skool 2520 op-amps in class-A mode with 49710HA's in the mix. These are a holographic op-amps to begin with but this wizardry has brought it to the next level. It is a design by my friend Carl and I think it's called a KAD Headphone Line amp.

This @50% gets a T60RP to comfortable loud levels so penty of juice, the balanced will have more so can't wait and he has PCB's on order too! Some of these might get a limited run!

God Damn! I could listen to this liquid holograph all day!


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## HeyManslowdown97 (Aug 30, 2019)

CoiL said:


> OPA2228



One of my all time favorites but you gotta get the “opa2228au” its the “br” of its counterpart the  Ad8620 but wayyy less $$. The ad8620 applications goes beyond audio like ultrasound because of it’s insane performance. Why is this important in Audio because the damn thing can be eq’ed (it runs sharp on the tremble aggressive around the 1.5 to 12k??) and can be tamed and “fine tuned” with some digital filters! 

The opa828/827 have this quality but comes in single (don’t run sharp either) and are slightly more $ than the the opa2228 (sound-wise). It’s a rad chip bro, it’s got this graininess that’s pleasant like a 35mm picture from 60s French or Italian  Cinema remastered in digital!

The AD chips have THE best bass response I’ve ever heard but as counterpoint laid-back “Balance” of the burr-brown is what I am after! The opa1612 is freakin’ amazing but ‘needs’ something like the Ad “Ooomph.” 

Shout out to the National Audio engineers  (now owned by TI) the NwGuy was right about them. The NJM4562 is one of best headphone amps but I prefer better sound quality of other amps (soundwise). Which none of which would be possible sans the contribution tho the National Semiconductor Audio engineers!


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## Rroff

Mad Max said:


> I haven't had any bad experience with Cirrus Logic DACs myself. The only DACs that I've really disliked are just those ESS DACs. Disgusting sound.
> I still prefer BB, AKM, and ADI, which are still common. AKM sure is popular these days.
> I had not tried PCM1795 until the Teac P90 and FiiO E18. Wow, what beautiful sound.
> 
> Also, forgot to recommend ADA4001 over ADA4004. 4001 is uber transparent, more than most opamps. Specified for mic preamps, and I can hear why it would rock hard in such, especially in recording gear.



I'm generally not a fan of Cirrus Logic DACs myself - most of their mainstream lines sound a bit dulling and muddy to my ears and while the higher tier parts are a little better I still find it hard to get excited by them.

ESS DACs do tend to have quite a "power punchy" sound as someone said above which is going to be a bit Marmite - my Creative AE-5 has one coupled with LM4562 opamps and that has quite a big punchy "high-res" sound, which is actually quite decent for video gaming, but a touch brittle and cold for music listening - but you can also do interesting things with ESS DACs depending on the supporting circuitry.

The TI PCM series tend to be pretty solid.


----------



## ReAlien (Sep 20, 2019)

Hi, All! I'm currently trying V6 Vivids in my DAC and I like the sound over my OPA627 very much BUT I experience rather extra level of HF than I need. I'm considering buying Sparkos SS3602 instead, anyone can tell if Sparkos are less prone to brightness or not?


----------



## ztwindwalker

ReAlien said:


> Hi, All! I'm currently trying V6 Vivids in my DAC and I like the sound over my OPA627 very much BUT I experience rather extra level of HF than I need. I'm considering buying Sparkos SS3602 instead, anyone can tell if Sparkos are less prone to brightness or not?



You can try opa828，the modern version of opa627.


----------



## ReAlien

ztwindwalker said:


> You can try opa828，the modern version of opa627.


Do you have any info on how opa828 stands against discrete solutions?


----------



## ztwindwalker

In speed sensitive applications,such as I/V convert or active LPF in audio,I always prefer ICs.

Discrete solutions often have more output current,because they have batter output stage.

My phonitor 2 is based on discrete OPAMPs, but I will not consider SPL phonitor x since they use this solution on a DAC.


----------



## ashleydoormat

So I just bought some SOIC op amps and dip adapters but the adapter's legs/pins are two big to fit in the dip socket! How do people roll SOIC op amps here?


----------



## ztwindwalker

ashleydoormat said:


> So I just bought some SOIC op amps and dip adapters but the adapter's legs/pins are two big to fit in the dip socket! How do people roll SOIC op amps here?



You just brought the wrong pins. the pins of an adapter should looks like that in an IC socket.


----------



## ashleydoormat

ztwindwalker said:


> You just brought the wrong pins. the pins of an adapter should looks like that in an IC socket.


Can you give me part number or link for the adapter I should be looking at? TIA!


----------



## ztwindwalker

ashleydoormat said:


> Can you give me part number or link for the adapter I should be looking at? TIA!


https://www.ebay.com/itm/PCB-Conver...hash=item2877318917:m:mG3UN4KnJaC-9e2YUSSROfg

Something like this,the left one in this link.


----------



## Ivan TT (Sep 28, 2019)

ashleydoormat said:


> Can you give me part number or link for the adapter I should be looking at? TIA!


Hi!
I use these pins:
https://www.aliexpress.com/item/32721243961.html
And pcbs like these:
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/191736126491
Edit: updated link


----------



## ashleydoormat

ztwindwalker said:


> https://www.ebay.com/itm/PCB-Conver...hash=item2877318917:m:mG3UN4KnJaC-9e2YUSSROfg
> 
> Something like this,the left one in this link.





Ivan TT said:


> Hi!
> I use these pins:
> https://s.click.aliexpress.com/e/KXWW86Pq
> And pcbs like these:
> https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/191736126491



I'm thinking of just changing the pins of my existing adapter. The link for the pins doesn't work here? Anyone knows where I can find the correct pins?


----------



## HeyManslowdown97 (Oct 9, 2019)

Opa1692!

AD8066: THE best sounding bass op amp ever!


----------



## Jimmy24

OPA2107 anyone?


----------



## HeyManslowdown97

Jimmy24 said:


> OPA2107 anyone?



I love it! Probably my favorite op amp. It’s dark and deep but I know it’s not for everyone and maybe too dark for many! Also, what I have learned is that if rig is already dark, it may be best to go with an op amp that’s bright/neutral. 

I have Opa2111kp coming in the mail and I would love to compare the two for permanence or in combo. 

Since I can’t use two opa627 on an adapter because of space restrictions. I’m happy with the Opa2107 with a relatively close audio signature! Also, I’ve heard that Opa627 can oscillate because of its high speed. 

I’d also love to try AD825 but it’s single op amp.


----------



## Jimmy24

HeyManslowdown97 said:


> I love it! Probably my favorite op amp. It’s dark and deep but I know it’s not for everyone and maybe too dark for many! Also, what I have learned is that if rig is already dark, it may be best to go with an op amp that’s bright/neutral.
> 
> I have Opa2111kp coming in the mail and I would love to compare the two for permanence or in combo.
> 
> ...



Would love to hear your impressions on those compared to the OPA2107. The next op-amp on my list is the OPA2210 but since it's MSOP I still need to solder it on the 8DIP adapter.

Been using the OPA2107 with my Whammy which I think has a neutral bright sound so it really pairs well. Been looking for the right combo of soundstage, warmth and punch and the 2701 delivers on those areas. I can't stress enough how good the HD650's sound.


----------



## HeyManslowdown97 (Oct 15, 2019)

Jimmy24 said:


> Been looking for the right combo of soundstage, warmth and punch...



The Opa2107 for me has a sweet spot for the tremble sans the harshness with a deep soundstage w/o being wide and distant and it’s laid back which doesn’t make it fatiguing for long listening seshs! 

I love the AD8066 it’s really alive and has the best sounding bass I’ve heard in op amp but it’s fatiguing for me. I also like the AD8620, it’s got a really nice dynamic sound but lacks the depth in detail soundstage of the Opa2107 and it’s bit too aggressive in the tremble. 

Finding the ”right” combo/op amps is a challenge with a lot of trial and error. 



Jimmy24 said:


> Would love to hear your impressions on those compared to the OPA2107. The next op-amp on my list is the OPA2210 but since it's MSOP I still need to solder it on the 8DIP adapter.



I haven’t tried the Opa2210 but lately I’ve been into obsolete chips that may not have the best specs but sound great (at least that’s the objective)! 

I’d like to try lt1028 but again it’s a single op amp!

I’d also like to try the Opa128 and Opa121 but there’s very little info on them sound wise!


----------



## LaughMoreDaily (Oct 15, 2019)

I wish people would mention both the devices and opamps they are trying in them, when they give their opinion.

I just ordered the Ziku HD-X10 DAP and I will let you know which opamps I think sound good in it when it arrives.


----------



## goodsguys

Just purchased sparkos opamps for an asus stxII soundcard and have replaced the 3 muses, 

What do think about increasing the size of the 220uf capacitor across the opamp power lines to help provide more power and stability. 

The sparkos are class A and have a higher current draw, do you think a larger cap, or a few more 220uf caps in parallel, would help.

Did read earlier about a 10uf silimic being good in this position, so decreasing the size of the capacitor seems another option.

Or am i entirely wrong, is it the atx power supply within the pc that is more important then local bypass capacitors.

Thanks!


----------



## HeyManslowdown97

LaughMoreDaily said:


> I wish people would mention both the devices and opamps they are trying in them, when they give their opinion



There are several reasons why I don’t like to say what device I’m putting my op amps in. One is that op amp itself has its own particular audio signature and how it compares to circuitry can really be affected  in either a positive or negative way as to how it’s implemented into a particular DAC. 

I don’t believe that there is a “better or worse” audio modern op amp. However, Many manufacturers today aren’t making op amps exclusively for audio unless it’s a company like Bursons or companies like TI or JRC making an exclusive audio line like “MUSE” or the 16xx series of audio amps made by TI. Moreover, the majority of those lines are built on previous archetypes of famous and glorious makeups of op amps made 20-30 years ago! 

The main difference is better nano technology computations with 3D printers/laser trimmings and better transistors, etc. For audio application _ any _ modern op amp will be able to perform at a high level (provided it’s a genuine part that’s gone through a quality controlled testing in the supply chain). 

So then it becomes a question of taste and musical preferences. Some people prefer narrow or a wide soundstage due to what will enhance the music genre they prefer, etc and some will prefer what can described as “warm” “bright” “neutral” and any other adjective used to describe sound quality/signature. 

I actually don’t have problem mentioning what devices I’m using my op amps on if it’s a formed in question of a device I own like ”what would sound good in x device...” to give suggestion. But to state it in general I feel muddy’s the waters.


----------



## bogginhead

Has anyone here used or heard any gear using the AD LT1169?  I received a couple of samples of it in DIP-8 and I can't find out much about it online.  Supposedly it's supposed to have very low distortion, but I can't seem to find anything else on it.


----------



## HeyManslowdown97

bogginhead said:


> Has anyone here used or heard any gear using the AD LT1169?



Funny you mentioned the LT1169 because I did a cross reference of AD part for the Opa2111 (which I get in the mail today & has very little said about IT on the internet). 

Your best bet (if you don’t get response) is to try it and if you feel comfortable sharing your thoughts and opinions on the thread. 

If it helps Lt1113 also popped up so they may sound similar or relate since they both dual fet with low noise?? Not sure as I haven’t used either??


----------



## goodsguys

How much of a difference is there between sparkos dual and muse 02, i know the answer is somewhere in this thread but to help me from having to read through hundreds of pages, can you please help.
Is there a minor improvement, or is it more night-and-day.
Thank you


----------



## spbkaizo

HeyManslowdown97 said:


> Hey has anyone tried the ADA4625?
> 
> https://www.analog.com/en/products/ada4625-1.html



I've just placed one into a headphone amp.  I really really like it.  Worth getting to experiment with, great clean sound and seems to help low end a lot.


----------



## HeyManslowdown97

spbkaizo said:


> I've just placed one into a headphone amp.  I really really like it.  Worth getting to experiment with, great clean sound and seems to help low end a lot.



Thanks for the feedback. How is the soundstage? That’s my biggest concern after the cleanest


----------



## Rroff (Oct 21, 2019)

LaughMoreDaily said:


> I wish people would mention both the devices and opamps they are trying in them, when they give their opinion.



Mostly my impressions have been from various DIY amps so mentioning the device itself is somewhat meaningless to most people :s (generally loosely of similar principles to the O2 and PBA amps but also fairly different from the stock version of those designs). DAC wise fairly varied - including a SB X-Fi, Creative AE-5 and a couple of standalone DACs that use variants of the ESS Sabre and I've built some DIY DACs based on TI's PCM series.

Broadly the impression of an opamp is similar but different circuits can change things - the biggest difference I find, other than what actual stage the opamp is used in, is what if any capacitor is close to and bridging the + and - power pins of an opamp especially perception of bass and soundstage.



HeyManslowdown97 said:


> I love the AD8066 it’s really alive and has the best sounding bass I’ve heard in op amp but it’s fatiguing for me.



AD8066 is something else if you use it in a "dual mono" type pseudo balanced amp with an active ground with a 10uf Nichicon FG or KZ series bridging the power pins - does need headphones with separate grounds to each driver though and you do get slightly increased noise floor compared to some other approaches but the overall result is really pleasing for music listening - the upper mid-range veil is almost entirely gone and the result is far more effortless sound.


----------



## HeyManslowdown97

Rroff said:


> AD8066 is something else if you use it in a "dual mono" type pseudo balanced amp with an active ground with a 10uf Nichicon FG or KZ series bridging the power pins - does need headphones with separate grounds to each driver though and you do get slightly increased noise floor compared to some other approaches but the overall result is really pleasing for music listening - the upper mid-range veil is almost entirely gone and the result is far more effortless sound.



Awesome stuff. Great explanation about the relationships between ICs and Op Amps too! 

In my experience with op amps it has been the exact same. I’ve tweet with the caps and improved power supplies and lot of the “problems” went away immediately with my favorite op amps ! The “trick” is finding the right tweak!!!! 

Right now, I’m rocking a Opa2111kp. It’s really, really nice. I love how it’s balanced with nice bass and tremble. Love the Opa2107 for its laid back and dark sounding but that (I know is an acquired taste). 

If I can somehow get the Opa627 2x to fit in a limited space dap and prevent it from oscillating that would be my first choice! 

I love the dynamic sound of the AD8620 but it’s a little to harsh in the high frequency. If someone can “solve” that problem with tweaks on a dac IC it would make it something really, really special. 

As far as quality, all the modern op amps are of high performance (IMO) the only thing to concern oneself is with finding the best Audio signature and then optimize it. It’s also a good ideas to know what you want in a sound and what genre you listen to most for best audio signature. If you are lucky to have multiple DACs with DIY op amp rolling  Capabilities even better!  

Thanks the to tip with the AD8066. Will experiment with that rig you presented here! The bass is just soo sweet on that op amp!


----------



## mwildebeast

Spektykles said:


> Just finished some basic portable stuff with 3x P(rototype)-OPA1656 and 2x OPA1688 in parallel, wow 1656 heat up like hell compare to 1652 in this same system. still in burn in phase (yes a believer here  )



I know this thread and post are a bit old, but after your op-amps burned in, did you notice any sort of meaningful difference in sound quality? I actually recognize the PCB as coming from a Topping NX4 DSD, since I have one, and I began looking into the 1656 because like you, I wanted to upgrade the op-amps that Topping used (mostly just because I can lol). I already have some 1656's on the way, and they should be here by the weekend. It would be great to know if it will be worth the effort!

I was going to replace the 1688's with the 1656's as well, but it sounds like the 1656's aren't really designed for driving headphones (due to the capacitive loads). I mostly wanted to replace the 1688's with the hope of getting more output current. Plus, the 1656 seems to have generally better specs.


----------



## Rroff

goodsguys said:


> What do think about increasing the size of the 220uf capacitor across the opamp power lines to help provide more power and stability.
> 
> The sparkos are class A and have a higher current draw, do you think a larger cap, or a few more 220uf caps in parallel, would help.
> 
> ...



I wouldn't go changing 220uf capacitors that are close to the opamp at random - they are often specced at 220uf for ESR reasons both in terms of power delivery to the opamp(s) themselves and if applicable the regulators feeding them will sometimes have an ESR range needed for stability - without knowing the requirements of the broader circuit the results could be unknown.

Bulk capacitor banks in the power supply phase (you'll often find 4x 470uf - 2 per rail) and generally you can add or upgrade the capacitors there to improve the power filtering without issue but that won't necessarily help if the opamps need a local supply to deal with current spikes (though this is less usual to find on a PC soundcard).

There are various combinations of 10uf (usually paired with a 0.1-0.22uf ceramic or film) either rail to ground or rail to rail that can have an impact on performance but generally specific to certain opamps like the LM4562 that might be having stability issues in certain circuits.


----------



## Jimmy24 (Oct 25, 2019)

mwildebeast said:


> I know this thread and post are a bit old, but after your op-amps burned in, did you notice any sort of meaningful difference in sound quality? I actually recognize the PCB as coming from a Topping NX4 DSD, since I have one, and I began looking into the 1656 because like you, I wanted to upgrade the op-amps that Topping used (mostly just because I can lol). I already have some 1656's on the way, and they should be here by the weekend. It would be great to know if it will be worth the effort!
> 
> I was going to replace the 1688's with the 1656's as well, but it sounds like the 1656's aren't really designed for driving headphones (due to the capacitive loads). I mostly wanted to replace the 1688's with the hope of getting more output current. Plus, the 1656 seems to have generally better specs.



No noticeable difference as far as I can tell for the LM833N, OPA2107, and OPA2210. The Burson V6 Vivid's have about 20 hours but they told me I needed at least 100 hours before getting its full sound. I will let you know when I go past that and see if I notice a difference.


----------



## Jimmy24 (Oct 25, 2019)

goodsguys said:


> How much of a difference is there between sparkos dual and muse 02, i know the answer is somewhere in this thread but to help me from having to read through hundreds of pages, can you please help.
> Is there a minor improvement, or is it more night-and-day.
> Thank you



I would like to know how the MUSE02 compares with OPA2107, but would like to know people's thoughts on the Sparkos Dual, is it worth it?


----------



## HeyManslowdown97

Maybe stupid question but is it possible to replace BUF634 with a single op amp like Opa627?? 

Also can the BUF634 be used a headphone driving output amp if you put two onto a SOP-to-Dip adapter. If so what sound signature would “buffer” op amp have like the BUF634??!


----------



## endia

HeyManslowdown97 said:


> Maybe stupid question but is it possible to replace BUF634 with a single op amp like Opa627??



you can but you need an adapter since they are not pin compatible. also while doing that, you're losing buffers high output current (250 mA buf634 vs 55 mA opa627) and almost zero output impedance advantages of buffer..



HeyManslowdown97 said:


> Also can the BUF634 be used a headphone driving output amp if you put two onto a SOP-to-Dip adapter. If so what sound signature would “buffer” op amp have like the BUF634??!


buffers do not amplify signal voltage, it's output is same as the input voltage.. using it in the gain stage is pointless..


----------



## HeyManslowdown97 (Nov 1, 2019)

endia said:


> buffers do not amplify signal voltage, it's output is same as the input voltage.. using it in the gain stage is pointless..



This would explain why it’s * awesome * when you have circuitry that has one or two independent Buffer slots for specific buffer op amps to feed current to output stage (if I have this correct) and to “power” the audio op amps as the input and output remain the same! 

Thanks for simple explanation. I’m afraid the internet doesn’t really do a great explanation in what the buffer does to the audio frequency in simple terms! 

Side note: I have a portable player with adequate power supply and some legendary op amps I’ve rolled sound exactly how people on this thread and others say they sound like! 

I’m curious about coupling film caps because this particular circuitry has them surrounded around the Dip8 and they sound better to my ears but it could be a placebo effect (I’d like to know what the advantage of coupling film caps around an op amp (if any??)

Btw: this player https://www.cssbuy.com/item-584795097581.html circuitry is almost exactly like the Zishan DSD 699 but it’s got the ak4497eq Chip and drive any low impedence headphones. The screws aren’t your typical Philips so I ordered the wowstick electric screwdriver set on AliExpress but it sounds really good when I change only one op amp with a genuine AD8620. 

It’s worth the upgrade to the Zishan DSD 699 if you wanted the extra stages like the latter!


----------



## raoultrifan

HeyManslowdown97 said:


> Maybe stupid question but is it possible to replace BUF634 with a single op amp like Opa627??


Makes no sense, because OPA627 can be successfully used in voltage-amplification-gain (gains <=5) or in low-pass-filter stage, I see not one single reason to use it in unity gain as an output buffer that can sustain a max. current of 45mA, while BUF634 can handle a max. output current of 250mA.



HeyManslowdown97 said:


> Also can the BUF634 be used a headphone driving output amp if you put two onto a SOP-to-Dip adapter. If so what sound signature would “buffer” op amp have like the BUF634??!


BUF634 or LME49600 are designed to operate as output buffers, so these operational amplifier chips will always work perfectly as output current boosters.
In case you want to replace an existing dual-opamp from one of your amplifier, might be more helpful to know what is that headamp and maybe some internal pictures or even the schematic. Usually, a SOP-DIP8 adapter should work fine, although BUF634 can be found in both SO8 and DIP8 packages.


A basic schematic for a headamp with BUF634 used as output buffer would be the below one, taken from TI's datasheet:


----------



## FritzS

Please take an eye to the new *BUF634A*
https://www.ti.com/product/BUF634A
https://www.ti.com/lit/ds/symlink/buf634a.pdf
https://e2e.ti.com/support/amplifie...placement-of-the-BUF634-with-the-new-BUF634A-


----------



## Jimmy24 (Nov 8, 2019)

Just tried the MUSES02 and compared it with the OPA2107. I gave it a good listen on my Whammy Amp with HD 650's (Mimby DAC). The MUSES02 does not have the same instrument separation and soundstage as the OPA2107. Because of this, the MUSES02 does not have the same life-like holographic quality as the OPA2107. Very disappointed as the MUSES02 is twice the cost. OPA2107 is just too good.


----------



## FritzS

OPA1632, SOIC, single OP, +-85 mA, Differential Output
https://www.ti.com/lit/ds/symlink/opa1632.pdf

LME49713 +-100 mA - but discontinued
https://media.digikey.com/pdf/Data Sheets/Texas Instruments PDFs/LME49713.pdf
https://www.diyaudio.com/forums/headphone-systems/297658-alternative-lme49713.html

LM6171 +-90 mA
https://www.ti.com/lit/ds/symlink/lm6171.pdf
https://www.diyaudio.com/forums/headphone-systems/297658-alternative-lme49713.html


----------



## HeyManslowdown97

raoultrifan said:


> Makes no sense, because OPA627 can be successfully used in voltage-amplification-gain (gains <=5) or in low-pass-filter stage, I see not one single reason to use it in unity gain as an output buffer that can sustain a max. current of 45mA, while BUF634 can handle a max. output current of 250mA.
> 
> 
> BUF634 or LME49600 are designed to operate as output buffers, so these operational amplifier chips will always work perfectly as output current boosters.
> ...



Yea I totally get it. The thing that threw me off was that a buffer is considered an “op amp” so I wasn’t clear about it’s functionality as being a one-trick-pony so-to-speak! 

How I understand it now is that when you do have a specific buffer amp you have a ton of options to drive your favorite op amp audio signature. This is a pretty near functionality if I have it correctly!


----------



## HeyManslowdown97

FritzS said:


> Please take an eye to the new *BUF634A*
> https://www.ti.com/product/BUF634A
> https://www.ti.com/lit/ds/symlink/buf634a.pdf
> https://e2e.ti.com/support/amplifie...placement-of-the-BUF634-with-the-new-BUF634A-



I have it. It is VERY powerful but I believe it needs the right circuitry and op amp to handle it in order to get its full effect and tame it because in my experience it does create noise with high gain. But again, this could be just me not understanding how to make it work properly! 

The datasheets and evaluation boards help so much in this area I’m learning to keep parts stable and effective!


----------



## HeyManslowdown97

FritzS said:


> Please read the data sheets!
> 
> https://www.renesas.com/eu/en/www/doc/datasheet/ha-5002.pdf
> 
> ...



Remembered this post and found a Dip8 adapter that’s pin-to-pin compatible but it only works when replacing the BUF634 for Ha-5002 on a Dip8. Hope this helps... 

https://www.cimarrontechnology.com/product/browndog-110101-ha5002-to-buf634-adapter


----------



## endia

HeyManslowdown97 said:


> Remembered this post and found a Dip8 adapter that’s pin-to-pin compatible but it only works when replacing the BUF634 for Ha-5002 on a Dip8. Hope this helps...
> 
> https://www.cimarrontechnology.com/product/browndog-110101-ha5002-to-buf634-adapter


just a warning for those who want to replace buf634 (or any other buffer) with ha5002 as output buffer; ha5002 has not short circuit protection so plugging or removing the plug from the circuit is potentially risky to damage ha5002s..


----------



## HeyManslowdown97 (Nov 12, 2019)

endia said:


> just a warning for those who want to replace buf634 (or any other buffer) with ha5002 as output buffer; ha5002 has not short circuit protection so plugging or removing the plug from the circuit is potentially risky to damage ha5002s..



Yep, so critical of a warning especially when modding because mistakes can/do commonly happen when DIYing and experimenting. 

The more you know the better! 


I just install the new BUF634A and it sounds great and I don’t feel the need for the supposed transparency I read about in the HA-5002!


----------



## gaz2613

Hey guys I have done a review of the SparkoS Labs discrete op amps on my site. Please feel free to take a peek:

https://www.audiosy.net/2019/11/21/sparkos-labs-ss3601-and-ss3602-discrete-op-amp-review/


----------



## redrol

Hey fellas, Im just now getting into Opamps.  So far the Muse02 really appeals to my ears.  I am surprised that the differences are so clearly audible.


----------



## escknx

redrol said:


> Hey fellas, Im just now getting into Opamps.  So far the Muse02 really appeals to my ears.  I am surprised that the differences are so clearly audible.


Yes OpAmps can make the big difference.
If you have a change, try Sparkos Labs discrete ones.


----------



## pelopidas

Burson V5 is another great one to try. Between Sparkos and Burson you are jumping straight into the pinnacle of what opamps can do. The cheaper chip opamps are still fun to roll though and teach you what to listen for in opamps. AD797 and LME49720 and LME49860 are some staples that you should try. Playing with those, including the Muses 02, will show you what Burson and Sparkos deliver.


----------



## LaughMoreDaily (Jan 14, 2020)

I gave up on rolling opamps. Have fun guys.

FYI, I was rolling in my Zishan's and Walnut's. I did so only on the daps, those are crap. 

I prefer real daps now like the Ziku HD-X10 and even though I can roll on it, I don't...


----------



## CoiL

redrol said:


> Hey fellas, Im just now getting into Opamps.  So far the Muse02 really appeals to my ears.  I am surprised that the differences are so clearly audible.


It all (result) depends on lot of things - implementation, design of PCB, DAC chip pairing, HW components etc. 

But if You want different tastes to try and if suitable with your source HW, then I recommend to try out OPA2228 and OPA1692. 
I`m freaking happy with my Aune T1 end result with those 2 chips pairing result.

Personally never got into MUSES chips as to me (on friends PC soundcard) did not impress enough to justify cost.



LaughMoreDaily said:


> I gave up on rolling opamps. Have fun guys.


Aaaannd why?


----------



## docentore

pelopidas said:


> Burson V5 is another great one to try. Between Sparkos and Burson you are jumping straight into the pinnacle of what opamps can do. The cheaper chip opamps are still fun to roll though and teach you what to listen for in opamps. AD797 and LME49720 and LME49860 are some staples that you should try. Playing with those, including the Muses 02, will show you what Burson and Sparkos deliver.



Good rec on the LME but @redrol  already has LM4562 which is same to 49720


----------



## pelopidas

docentore said:


> Good rec on the LME but @redrol  already has LM4562 which is same to 49720


I suppose I should have not been so lazy in my typing and clarified that he should try LME49720HA, the one in the metal can. It tends to have a better presentation as far as I recall. I know that LM4562 LME49720 and LME49860 are supposed to be technically the same but as far as I am concerned LM4562 < LME49720HA < LME49860 with the 49860 noticeably better. Another step up would be dual 49710's. Those actually are nice and with great detail IIRC.


----------



## carlmart (Jan 13, 2020)

Pity the LM48710 shows as obsolete at Mouser.


----------



## Baten

pelopidas said:


> I suppose I should have not been so lazy in my typing and clarified that he should try LME49720HA, the one in the metal can. It tends to have a better presentation as far as I recall. I know that LM4562 LME49720 and LME49860 are supposed to be technically the same but as far as I am concerned LM4562 < LME49720HA < LME49860 with the 49860 noticeably better. Another step up would be dual 49710's. Those actually are nice and with great detail IIRC.


The metal cans are generally fake though. Almost all pre-soldered on dip HA ones on ebay are.

This guy sells the real thing:
https://ebay.com/sch/m.html?_odkw=&...0&_trksid=m570.l1313&_nkw=LME49720HA&_sacat=0
but you'd have to solder the gold ones onto a dip switch yourself.


----------



## raoultrifan (Jan 14, 2020)

pelopidas said:


> LM4562 LME49720 and LME49860 are supposed to be technically the same but as far as I am concerned LM4562 < LME49720HA < LME49860 with the 49860 noticeably better.


Inside my Matrix HPA-3B with LME49860 the background noise was the highest, while with LME49720 or LM4562 was much lower. Tested while only swapping one opamp from one channel, so very easy to test the hiss with the headphones on the head, max. gain and max. volume with no input connected.
Like usually, YMMV, but for me background noise should be the lowest possible.

BTW, the best measuring opamps (THD, noise, IMD etc.) are the newest OPA1612 and OPA1654, so really worth trying.

L.E.: OPA1656 is what I actually meant to write.


----------



## Baten

raoultrifan said:


> BTW, the best measuring opamps (THD, noise, IMD etc.) are the newest OPA1612 and OPA1654, so really worth trying.



OPA1656 even better than OPA1654?


----------



## carlmart

Baten said:


> This guy sells the real thing:
> https://ebay.com/sch/m.html?_odkw=&...0&_trksid=m570.l1313&_nkw=LME49720HA&_sacat=0
> but you'd have to solder the gold ones onto a dip switch yourself.



Something is wrong on the URL, as it opens eBay, but not the seller.


----------



## Baten

carlmart said:


> Something is wrong on the URL, as it opens eBay, but not the seller.


All results are from the same seller for me, it's a search on the seller store. Should be correct 

you see the gold-plated metal cans?


----------



## raoultrifan

Baten said:


> OPA1656 even better than OPA1654?


OPA1656 is what I actually meant to say, thank you for noticing this! It's used in Geshelli Archel 2.5 PRO and it's incredible low noise and low THD.


----------



## Baten (Jan 14, 2020)

raoultrifan said:


> OPA1656 is what I actually meant to say, thank you for noticing this! It's used in Geshelli Archel 2.5 PRO and it's incredible low noise and low THD.


They're great to put in Burson amps too. Currently rocking those 1656 in IV/LPF  there's 1656 available on ebay pre-soldered and I verified it to be not fake. It's cheaper to solder yourself of course.


----------



## carlmart

Baten said:


> All results are from the same seller for me, it's a search on the seller store. Should be correct
> 
> you see the gold-plated metal cans?



No, I do not see any metal cans. 

Can you tell me the name of the seller? Then I may find him.


----------



## Baten

carlmart said:


> No, I do not see any metal cans.
> 
> Can you tell me the name of the seller? Then I may find him.


Weird! It's 
tevatronix


----------



## pelopidas

Baten said:


> The metal cans are generally fake though. Almost all pre-soldered on dip HA ones on ebay are.
> 
> This guy sells the real thing:
> https://ebay.com/sch/m.html?_odkw=&...0&_trksid=m570.l1313&_nkw=LME49720HA&_sacat=0
> but you'd have to solder the gold ones onto a dip switch yourself.


True but they are not that expensive from Mauser or Digi and soldering them yourself is easier than regular chips. I loved the 49713HA which were current feedback but when properly implemented were very very good. The LME49990 were also very nice chips, significantly better than the 49720 family. Of course they are discontinued as well...


----------



## Audio Addict

Has anyone tried this.  Shipping is expensive plus it is not inexpensive either.

https://staccatoaudio.com/portfolio_page/osh-dhb-open-sound-hybrid-dual-horizontal-discrete-opamp/


----------



## redrol

OK i've been testing the OPA2227, OPA2228, OPA2134, OPA1612, and the Muses 02.   The clear winners for me are the 2227/8 but I think the 8 has a slight edge in high end possibly? Yeah.  The Muses 02 is just gorgeous, warm and sexy.  I can't put it much differently.  Maybe slightly less extended but so so sweet.  I love it.  I clearly do not like the 1612 and 2134.  They sound too cluttered and i dunno, linear vs musical.


----------



## CoiL

redrol said:


> OK i've been testing the OPA2227, OPA2228, OPA2134, OPA1612, and the Muses 02.   The clear winners for me are the 2227/8 but I think the 8 has a slight edge in high end possibly? Yeah.  The Muses 02 is just gorgeous, warm and sexy.  I can't put it much differently.  Maybe slightly less extended but so so sweet.  I love it.  I clearly do not like the 1612 and 2134.  They sound too cluttered and i dunno, linear vs musical.


Same assessment by me. I just love how OPA2228 sounds in amp section paired with OPA1692 in DAC stage.
But lot of it depends also about implementation and pairing. But overall I think you are describing those opamps spot-on


----------



## FritzS

OPA2227/OPA2228 versus LME49860 in pre driver of an headphone amp stage?


----------



## Jimmy24

Have you guys tried the OPA627? This is a good one


----------



## FritzS

Jimmy24 said:


> Have you guys tried the OPA627? This is a good one


I had them in an other headphone amp, but AD797 seems me a bit better.


----------



## noplsestar (Mar 1, 2020)

pelopidas said:


> Burson V5 is another great one to try. Between Sparkos and Burson you are jumping straight into the pinnacle of what opamps can do. The cheaper chip opamps are still fun to roll though and teach you what to listen for in opamps. AD797 and LME49720 and LME49860 are some staples that you should try. Playing with those, including the Muses 02, will show you what Burson and Sparkos deliver.



When reading this review

http://passionforsound.lachlanfennen.com/burson-audio-v5i-opamp/

it seems that the burson is more of a side grade from eg OPA627. 
Pinnacle is always also bias, no? One likes more the center staged/ mid focused sound, the other the separation or soundstage etc. 


FritzS said:


> I had them in an other headphone amp, but AD797 seems me a bit better.


„Seems“ means you can’t say for sure, right? 
And what does „better“ mean to you? What’s better for some guy (more basssss) isn’t better for the other guy. 
Also I quote someone concerning the AD797:
„ the AD797 is not a good chip for headphone amplifiers, it's designed for a very high open gain with low noise in curcuits like microphone amp and phono stage amps.“

Would you differ from his statement? If so, how?

Also I‘d like to ask you guys who know what they are speaking about (I am not, I just pretend ahahahaha because I am completely new to the opamp thing and have not bought a new opamp and probably won’t do it except I am 100% sure it’s worth) if you think that it is good to change the OPA627 from this portable headphone amp that is also made for opamp switching:
https://penonaudio.com/dethonray-hpamp-ha-2.html?tag=DETHONRAY HPAMP HA-2
Thing is: I am pritty happy with it in getting a balanced sound with lots of details and good width (in comparison to the Vorzamp Duo II that I also have and that amp gives me the midcentric (plus bass) sound I am not so fond of) ... that’s why I guess the Burson V5i isn’t something for me (when believing the guy who wrote the review I posted above.

So is there an „upgrade“ possible without sacrificing anything I really like about that sound? What about the Sparkos? Are they „spark(os)ley“?

Thanks for any input. I am completely new to this, as said above. And to be honest, I better don’t want to dig too deep into that opamp thing as I dig once very deep into the IEM „tip rolling“ thing and never got out of it again until I sold every IEM and got me the Stellia


----------



## wein07

Hi everyone. Can anyone kindly advice if the 48710HA op amp in the picture if real or fake? Thank you!


----------



## FritzS

wein07 said:


> Hi everyone. Can anyone kindly advice if the 48710HA op amp in the picture if real or fake? Thank you!



*49710HA! *
https://www.head-fi.org/threads/the-opamp-thread.432749/page-94


----------



## Baten

FritzS said:


> *49710HA! *
> https://www.head-fi.org/threads/the-opamp-thread.432749/page-94


these are out of production though, no?

isn't it likely the ones out now are fake?


----------



## wein07

I bought mine like yearsss ago though. Just curious about their authenticity..


----------



## FritzS

Baten said:


> these are out of production though, no?
> 
> isn't it likely the ones out now are fake?


I think no, I have LME49710HA (single) and LME49720HA (dual) in my stock, both coming from the manufacturer direct. They looks like the same case.


----------



## wein07

FritzS said:


> I think no, I have LME49710HA (single) and LME49720HA (dual) in my stock, both coming from the manufacturer direct. They looks like the same case.



U referring to my pictures?


----------



## pelopidas

noplsestar said:


> When reading this review
> 
> http://passionforsound.lachlanfennen.com/burson-audio-v5i-opamp/
> 
> ...



Pinnacle is less bias and more hirearchy. Stating that some like center staged and mid focused sound while others like separation and sound-stage is bias because it is a preferential choice between the two. The reason why I gave the discreet opamps (Burson V5 SS and Sparkos) the Pinnacle moinker is because they both represent less compromise. They both exceed with separation and sound-stage with intimately staged and focused details while being warm and also fast. 

Better for me is that the sound is as closely reproduced to what was recorded.

As for "Seems" ... that is because the implementation matters.  
In my headphone amp, these are my impressions which are similar for some opamps and different for others from what they sounded like in the Xonar where you had I/V and a buffer or in something as simple as a CMOY. In my headphone amp I have the opamp performing gain and servo and then out to the buffer. This is a very different implementation to previous amps I had and benefits from being DC coupled with zero capacitors in the signal path. So this is how things "Seem" to me.
The AD797BRZ is really quite good and I have lived with it for a long time but have found better. The short-comings, for me, are a narrower sound stage (feels triangular) and less distinct separation of sounds compared to my current favorites. The trebble is a bit forward for my liking on cymbals.
The LME49720HA is another quite good one, but it has a shallower more 2D sound-stage and feels less dynamic and involving. The trebble can sometimes feel plastic. Sounds solid state.
The LME49860, no matter what anyone says, it not the LME49720. It has a warmer mid, better bass, better separation and better, more distinct details. It is a better opamp than then 49720. (I just A-B'd them a few times right now again and it's obvious.)
The LME49990 (discontinued! Why??) is another step up. Smoother, more coherent, good detail retrieval, more involving than the 49720. Was my longtime favorite until the Bursons.
OPA1692 is really good. Very detailed and fast. Hard to find a fault with it. In the Xonar it was too bright if in I/V and Buffer. If in I/V then it benefits from something warmer in buffer. Dark background and involving with really tight bass. Great for electronic.
Just to cause trouble  The Xonar came with the JRC2114D which everyone can agree was dull and flat in the Xonar. In my headphone amp it is not dull or veiled. It is actually really nice, almost tube like in its presentation. The bass is maybe slightly wooly, but not offensively so. It's really nice and relaxing to listen to. (Different circuit, different results. This one surprised me)
So why mention all these opamps, just to come to the Burson or Sparkos? Well, they do everything right that the other chip opamps do, but a little better. Everything is just that touch clearer, silkier, faster, better decay, cleaner separation.

That is why I called it a pinnacle because as for opamp technology right now they are at the top. But the other opamps are also good. If I had to give up my Bursons and only use a chip opamp, what would it be? The OPA2209. This one might even have better decay than the Bursons with reverb trails that are captivating. Fantastic bass that is tight and great dynamics. So, if you want the best get a Bursons V5 SS  or a Sparkos. If you want a really, really good 2nd best get the OPA2209. Either way, the circuit you stick them in matters.


----------



## noplsestar

pelopidas said:


> Pinnacle is less bias and more hirearchy. Stating that some like center staged and mid focused sound while others like separation and sound-stage is bias because it is a preferential choice between the two. The reason why I gave the discreet opamps (Burson V5 SS and Sparkos) the Pinnacle moinker is because they both represent less compromise. They both exceed with separation and sound-stage with intimately staged and focused details while being warm and also fast.
> 
> Better for me is that the sound is as closely reproduced to what was recorded.
> 
> ...


Thank you very much for your detailed and informative answer! Have you also heard the OPA627 that comes with my amp?


----------



## Jimmy24

FritzS said:


> I had them in an other headphone amp, but AD797 seems me a bit better.


 I'll have to try that one


----------



## Baten

pelopidas said:


> Pinnacle is less bias and more hirearchy. Stating that some like center staged and mid focused sound while others like separation and sound-stage is bias because it is a preferential choice between the two. The reason why I gave the discreet opamps (Burson V5 SS and Sparkos) the Pinnacle moinker is because they both represent less compromise. They both exceed with separation and sound-stage with intimately staged and focused details while being warm and also fast.
> 
> Better for me is that the sound is as closely reproduced to what was recorded.
> 
> ...


Tnx for the detailed info =)


----------



## pelopidas

noplsestar said:


> Thank you very much for your detailed and informative answer! Have you also heard the OPA627 that comes with my amp?


I have not had the chance to hear the famous OPA627. I would have to spend $100 to give it a listen. How about you try the OPA2209 and give us a comparison from your point of view.


----------



## leeperry

pelopidas said:


> I have not had the chance to hear the famous OPA627. I would have to spend $100 to give it a listen. How about you try the OPA2209 and give us a comparison from your point of view.


Not missing much as genuine 627BP is is way overpriced and not too happy when rolled blindly, all you get is a thick dark sound.

ADA4627-1B is another story, meant to trump it.


----------



## noplsestar

leeperry said:


> Not missing much as genuine 627BP is is way overpriced and not too happy when rolled blindly, all you get is a thick dark sound.
> 
> ADA4627-1B is another story, meant to trump it.


well, I don’t hear anything dark or thick. So I guess it’s also about how it is implemented? I possess the Dethonray HA-2. It has two of the TI OPA627 (for left and right channel). Don’t know if that says anything. As said, I am a noob and probably want to stay a noob, haha, because no time and money (or nerves) for opamp rolling. Hmmm. But I have learned a bit, if that’s for any good


----------



## FritzS

Are the four amps of OPA4209 in parallel enough for a headphone amp driver stage?


----------



## bogginhead

Has anyone here used any OPA627AUs with an SOIC to DIP adapter?  I have 4 AUs, and two of them came pre-soldered to the adapter already.  Did a lot of research on the real / fake versions of these guys, so I made sure the chips I purchased were definitely legit.  But so far, neither pair of the AUs will work with my FIIO E12 DIY portable amplifier; I don't understand it, honestly.  I've also seen pictures of what looks like some extra / different soldering on other people's adapters using these than what I've tried / have, but being the novice that I am with electronic components and soldering I really wouldn't know or understand what the difference is between the two.  The DIY works fine with any other op-amps, too; it's just these that have the issue.


----------



## docentore

bogginhead said:


> Has anyone here used any OPA627AUs with an SOIC to DIP adapter?  I have 4 AUs, and two of them came pre-soldered to the adapter already.  Did a lot of research on the real / fake versions of these guys, so I made sure the chips I purchased were definitely legit.  But so far, neither pair of the AUs will work with my FIIO E12 DIY portable amplifier; I don't understand it, honestly.  I've also seen pictures of what looks like some extra / different soldering on other people's adapters using these than what I've tried / have, but being the novice that I am with electronic components and soldering I really wouldn't know or understand what the difference is between the two.  The DIY works fine with any other op-amps, too; it's just these that have the issue.


OPA627 is single opamp while E12 DIY takes dual channel opamp. Unless you have the 2 OPA627's installed on the apadter.


----------



## bogginhead

docentore said:


> OPA627 is single opamp while E12 DIY takes dual channel opamp. Unless you have the 2 OPA627's installed on the apadter.


Yeah, I've got two a piece installed on the adapters.


----------



## redrol

I just got a Burson V6 Vivid and stuck it in my Xduoo 05+.  Initial impressions are VERY good.  I've got 6 TIs and the Muse 02 at the moment for testing.  V6 is FAR better than any of the TI's and it's not subtle.  It's bold and rippling with detail and power.  Instant love.  Will post a more in depth review.


----------



## morpheus620 (Apr 11, 2020)

I bought 2 Opa2228 for my Topping A50. The sound is now warm and very clean. I'm happy ^^

LME49720 are installed as standard. Is the difference to these big?

E: In addition I bought LME49860 but with this I have strong distortions. It may be because of the circuit of the A50.


----------



## redrol

IF you enjoy the OPA2228 the Burson V6 is next level.  Not that the 2228 is bad, it isn't.  V6 is a step up in extension, control, texture, etc.


----------



## morpheus620

Only original DIP8 fit in the A50 topping. Everything else is too high.


----------



## redrol

Ah yeah, the V5i can fit that nicely, or the Muse 02.


----------



## Baten

morpheus620 said:


> Only original DIP8 fit in the A50 topping. Everything else is too high.


there are extenders like this, though
https://www.audiophonics.fr/en/comp...-opa-dip8-copper-occ-silver-30mm-p-13046.html


----------



## morpheus620

redrol said:


> Ah yeah, the V5i can fit that nicely, or the Muse 02.


The V5i doesn't fit. I have another one of my Fostex HP-A4. Only the standard op amps fit.


----------



## CoiL

morpheus620 said:


> I bought 2 Opa2228 for my Topping A50. The sound is now warm and very clean. I'm happy ^^





redrol said:


> IF you enjoy the OPA2228 the Burson V6 is next level.  Not that the 2228 is bad, it isn't.  V6 is a step up in extension, control, texture, etc.


It all depends on implementation but overall OPA2228 is VERY good and cheap opamp IMHO. Especially when paired with very clean&detailed ultra-low-distortion chips in DAC-differential output like OPA1612AID / OPA1692IDR / AD8599. 
I`m settled with OPA1692IDR + OPA2228 - so open, airy, natural "smooth" timbre but with awesome transparency, layering, clarity and micro-details at same time.


----------



## morpheus620

I still have a topping D10 as a DAC an a  topping E30. I like the topping D10 a lot, although it is cheaper.
With the D10 you can change the op-amp. I am considering buying the OPA1692 because you are satisfied with it or with this combination.
sorry for my english.


----------



## CoiL

morpheus620 said:


> I still have a topping D10 as a DAC an a  topping E30. I like the topping D10 a lot, although it is cheaper.
> With the D10 you can change the op-amp. I am considering buying the OPA1692 because you are satisfied with it or with this combination.
> sorry for my english.


Note that OPA1692IDR is SOIC-8 and needs adapter to use with D10.


----------



## redrol

Messing with my Xduoo today.  Got the capacitor right near my sockets out of the way... whew. 






Now with V6 Vivid:


----------



## mhhd

imran27 said:


> Damn, I was just wondering about it a week ago. I saw these on Element14. Technically they measure worse.
> 
> Anyways, my next investment would be in OPA1652 and probably ADA4610-1/-2 (this I am really hopeful for)



Hi Imran,
were you ever able to compare ADA4610 to others?
Thank you very much!


----------



## imran27

mhhd said:


> Hi Imran,
> were you ever able to compare ADA4610 to others?
> Thank you very much!


I have never had ADA4610 actually. I want to try that one soon


----------



## mhhd

imran27 said:


> I have never had ADA4610 actually. I want to try that one soon


Hello Imran,

Thank you for your response! I have some ADA4610 lying around and I wonder if they were suitable for cases where both the inputs are being used like a differential amplifier or summer stage. Unfortunately Analog does not provide large signal responses for inverting input (negative gain) in the data sheet. And I am just an amateur, able to solder and happy to be able to interpret some data with the help of people like you.

OPA1692 seems very good suited for a a differential amplifier or summer stage as you already explained.

Thanks again,

Martin


----------



## Rob43

Has anyone tried the OPA1656 Op Amp yet?

They will use a bit more power when compared to something like the OPA1692, but they are getting very high praise as being exceptionally musical.   


Rob43


----------



## HiFan

Rob43 said:


> Has anyone tried the OPA1656 Op Amp yet?
> 
> They will use a bit more power when compared to something like the OPA1692, but they are getting very high praise as being exceptionally musical.
> 
> ...



I run opa1656 in my modded HA21. It partially depends on your circuit and some doesn't make opamps sound drastically different.

I think 1656 is better than 1692 in my gear. OPA2210 is also a good chip if it works.


----------



## HeyManslowdown97

HiFan said:


> I think 1656 is better than 1692 in my gear.



Actually this is related to my question. I have both the Opa1692 and the Opa1656. The Opa1692 is bi polar op amp and Opa1656 is CMOS.

What are the difference between CMOS, Bi Polar, and jfets Op Amp amps sonically? When and where to choose one or the other ? What “combos” work best in certain modular/stage chains?

Lastly, not often mentioned about the Opa1692 is that not only does it have a wide voltage range, it ONLY consumes 650 µA per Channel! These bad boys give you impressive battery life in portable music players/headphones without compromising high audio performance- they are simply amazing for this application!

The Opa1692 is one of the best audio op amps ever made for what it achieves! (IMHO).

I also agree with someone who talked about the best combinations for the Opa2228 and the Opa1692 being a good choice. If you get that sucker (opa2228) stable, Combined with Opa1692 or Opa1612/2211- Holy Crap it’s sounds amazing. (Haven’t tried it with AD8599 yet). It just comes alive and the soundstage is deep, transparent and the timbre is warm (with NO harsh tremble) and tender. Oh my and lush!

Getting back to the Opa1692 my only “complaint” is I wish the Opa1692 had a higher GBW; it’s only about 5.5. But with the and higher slew rate some compromises had to be met so it could make its benchmarks for low power consumption w/o sacrificing performance. That said, make no mistake about it, it’s bad*** af!


----------



## HiFan (Jun 12, 2020)

HeyManslowdown97 said:


> Actually this is related to my question. I have both the Opa1692 and the Opa1656. The Opa1692 is bi polar op amp and Opa1656 is CMOS.
> 
> What are the difference between CMOS, Bi Polar, and jfets Op Amp amps sonically? When and where to choose one or the other ? What “combos” work best in certain modular/stage chains?
> 
> ...



It really depends on your circuit. I have several amps that takes dip-8 opamps, and I have found not all make a difference. In my particular amp, opa1692 has narrower sound stage than opa1656, as 1692 is designed for portbable use with trade-off (low power draw).

Bipolar or FET or CMOS depends on application due to noise type. Bipolar rejects current noise better, while the other two voltage noise generally speaking. But opa1656 is just lower noise & lower distortion than opa1692 according to datasheet. So in your particular case, I don't think that input stage matters a lot to you.

BTW, my to go choice for BJT opamp is opa1612, which is excellent in specs and stable in most of my amps.


----------



## HeyManslowdown97 (Jun 12, 2020)

HiFan said:


> BTW, my to go choice for BJT opamp is opa1612, which is excellent in specs and stable in most of my amps.



Have you tried Opa2156? It too is CMOS audio amp. I plan on getting some soon!

I agree with you on opa1692 being too narrow compared to the Opa1656. The Opa1656 has a much wider and better soundstage.

Ha ha it's funny because I'm a wide and far reached detailed and accurate fanboy and some people find too many details to be annoying.

I prefer the opa2211 over the opa1612 (same chip but with less better specs). The Opa1612 is the audio version so they made the specs slightly worse. Just feel the better spec’d amp is better for the circuit (performance/health wise).

I really love LT1028! It's power-hungry, thou. The LT1028 is by far better than the Opa1692. I would describe the LT1028 as a digitally clean sound. Some may prefer more noise with less resolution. I listen mostly to DSD files with 1-bit rate so it's already at low resolution so it ”sounds” more musicial and natural (whatever that means?). However, at higher resolution 24 bit or above in PCM it will sound clinical if the noise levels and op amp/circuit performs at the high res levels.

The reason is that like a HD resolution in tvs, the imaging and clarity changes and improves. That's why in lower resolution like 16 bit they add noise aka Dithering to smooth out some distortion and actually makes it sound pleasant and fluid in files and from track-to-track. I like a little bit of noise myself when its pleasant.

I would imagine CMOS opamp hit their spec sheets performance in CMOS audio application. Meaning the audio circuit designed for them.

I've actually used CMOS LDOs designed for audio and they improve the noise levels immensely! There is a paper out there that I read online comparing the Opa1656 to Opa1612. If I remember correctly in some areas the Opa1656 outperforms the Opa1612 however, CMOS still don’t outperform across the frequency spectrum because CMOS aren’t at ultra low noise levels that bi polar can easily perform from in-put current and output noise??? Something like that.

CMOS look promising for the future when/if they start outperforming even BJTs. CMOS may also be more accurate since most of the best clocks for low powered devices and low frequencies are made from CMOS. It's actually fascinating to read the CMOS and its potential today! At first, like in the 1960s it was hard to stabilize and control them but now...

I like Fets not as clear and less “airy” as bipolar but they are more musical with really pleasant and less fatiguing soundstages in my opinion. They can sound grainy but that depends on the circuit  what application it’s in. Some believe Jfets/Fets sound tuber, unnatural and less open. I don’t though. 

Just about to order some lt6018 which is supposed to be the upgrade to the lt1028. Also wanna pick up some opa2277 similar specs to Opa1692. Has anybody heard them before??


----------



## morpheus620

I have an AMP that uses 2 dual op amps (left and right). can I also use single op amps?


----------



## endia (Jun 12, 2020)

morpheus620 said:


> I have an AMP that uses 2 dual op amps (left and right). can I also use single op amps?


if it designed to work with dual opamps, no, you can't just swap them. but you can use 4 single opamps with 2 'single to dual' adapters.. especially in case if you want to try spesific single opamps, say, opa627 or ad797 etc..


----------



## HeyManslowdown97

mhhd said:


> Hi Imran,
> were you ever able to compare ADA4610 to others?
> Thank you very much!



I have ADA4610-2, ADA4637-1and ADA4625-2 in the ADA46** series 

A lot of DIY audio community compares them to the famous Burr-Brown JFETS Opa627 and Opa637.

Spec-wise they are almost on par but the soundstages sound totally different in my opinion. 

To me, the Burr-Brown laid back sound is almost exclusively heard on those chips and ADI also have quick bass response and the soundstage is just more pronounced in a good way!

The ADI chips in my opinion do not have the deep soundstage as the Burr-Browns with exception of a few but they have excellent bass response and are fast af!

If I had to recommend that I have in the ADA46** family would be ADA4625. It’s the fastest and cleanest JFET and newest. They also have ADI Fast settling which definitely works! These chips are fast!

ADA46** family are also less aggressive unlike other ADI chips.

These chips sound fantastic In Bass intensive music (like dance music, electronic and an intimate soundstage of acoustic music like Jazz in my opinion.

ADI and LME (National chips) have similar traits of power, fast and excellent low frequency response. But again sound totally different.

For personal use, I like most of TI Burr-Browns and some LT chips but If I’m having party or am listening to a particular music Genre I know it would sound better- hands down ADI and the LT are the way to go for me. There’s also the portable vs home entertainment difference which is yet another rabbit hole. Haha

I don’t have any NJC op amps but the MUSE series specs don’t knock me out of seat when I read them for the price but I don’t own them to say how they sound!

In Layman’s terms each high quality audio op amp sound great but present a different ambience and for each setup portable vs home there’s different recommendations so-to-speak.


----------



## Rob43 (Jun 12, 2020)

HiFan said:


> ..... In my particular amp, opa1692 has narrower sound stage than opa1656, as 1692 is designed for portbable use with trade-off (low power draw).



I'm saying this to everyone:

For me personally, I'd rather listen to Full/Great sounding music for a shorter amount of time, vs music with a narrower sound stage for a longer amount of time.


Rob43


----------



## HeyManslowdown97

Rob43 said:


> I'm saying this to everyone:
> 
> For me personally, I'd rather listen to Full/Great sounding music for a shorter amount of time, vs music with a narrower sound stage for a longer amount of time.
> 
> ...



In response and because I started this assault on the Opa1692. It’s not that much of a night and day difference in terms of wider soundstage and actually you only notice it on longer listening seshes. It’s just that the details aren’t as pronounced but you don’t “miss” any details. Opa1692 actually has a lower CMRR anywhere from 120-140 dB (according to Mouser) vs Opa1656. It’s also a lot quieter and has a faster slew rate (I believe). I believe that range is determined by the DAC chips specs so that’s a factor! 

Also it’s goes beyond just listening for more hours, if you have a battery powered music player the less current you use the more output current you have for an output stage op amp for current hungry iems. It also gives a lot of portable option especially if it’s not you main op amp as MOST balanced, Line out or SE go through stages.
When you get more of understanding  of How circuits affect op amps and what the correlation they have with add components like op amps “act” in certain circumstances you start to realize there’s no all encompassing holy grail op amp.

This does take some experience and hands on work and reading others’ theories and takes helps with your own blindspots and sometimes disagreements (totally normal).

For instance, many in the diy don’t like adding caps to circuits because it changes the op amps sound which to me is a benign argument.

In my view you add caps with ESR or ESL to a op amps in either the in put or out put to improve biasing and filtering. Sure, if you take too much off aliasing it will sound worse but if experiment with caps and coupling you can get op amps to maximize or even Exceed their own benchmarks improving the sound of a said op amp you like. If so, congrats you made something special sounding to your ears!

Also, some mediums like Vinyl requires a pre Phono set up and some solid state op amps outputs are already cleaner have lower noise levels than the distorted median so there’s no need for extra caps.

the point I’m trying to make is to always keep an open mind. The more you experience in this hobby the more your perceptions will shift...


----------



## Rob43

HeyManslowdown97 said:


> In response and because I started this assault on the Opa1692. It’s not that much of a night and day difference in terms of wider soundstage and actually you only notice it on longer listening seshes. It’s just that the details aren’t as pronounced but you don’t “miss” any details. Opa1692 actually has a lower CMRR anywhere from 120-140 dB (according to Mouser) vs Opa1656. It’s also a lot quieter and has a faster slew rate (I believe). I believe that range is determined by the DAC chips specs so that’s a factor!
> 
> Also it’s goes beyond just listening for more hours, if you have a battery powered music player the less current you use the more output current you have for an output stage op amp for current hungry iems. It also gives a lot of portable option especially if it’s not you main op amp as MOST balanced, Line out or SE go through stages.
> When you get more of understanding  of How circuits affect op amps and what the correlation they have with add components like op amps “act” in certain circumstances you start to realize there’s no all encompassing holy grail op amp.
> ...



I'll give you this, you like to write a lot...

I would tell you to also keep an open mind. 

So when talking about inexpensive parts like the Op Amps we're discussing, the best sounding part gets the job every time . Even if this means the length of play is reduced. 



Rob43


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## HeyManslowdown97 (Jun 12, 2020)

Rob43 said:


> I'll give you this, you like to write a lot...
> 
> I would tell you to also keep an open mind.
> 
> ...



There’s short hand when discussing this stuff with platitudes, anecdotal evidence and being passive aggressive guised as keeping an open minded because of your chosen style of brevity for thread contributions is unwelcoming and can seen as bullying.


----------



## Rob43

HeyManslowdown97 said:


> There’s short hand when discussing this stuff and being passive aggressive guised as keeping an open minded because of your chosen style of brevity for thread contributions.



Sure, if you believe that I say you should run with that.


Rob43


----------



## HeyManslowdown97

Rob43 said:


> Sure, if you believe that I say you should run with that.
> 
> 
> Rob43



Fair enough, do yourself a favor and please select the “ignore” and censor yourself from long hand thread contributions like mine. Clearly you are well above them.


----------



## Rob43

HeyManslowdown97 said:


> Fair enough, do yourself a favor and please select the “ignore” and censor yourself from long hand thread contributions like mine. Clearly you are well above them.



Thanks, I'll take that into consideration...


Rob43


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## HeyManslowdown97 (Jun 12, 2020)

Here’s a great article comparing opa2156 CMO vs opa1612. My understand if noise isn’t a problem the opa1656 is great alternative to the opa1612. Both (I believe have Fet-inputs)

There’s also 2189 CMOS audio op amp has impressive specs of an impressive was designed for MUX friendly DACs and multichannel dacs!

https://quantasylum.com/blogs/news/opa2156-hifi-in-cmos

datasheet fro opa2156 CMOS op amp. Slightly better specs/= to Opa1656 for audio purposes.

https://www.ti.com/lit/ds/symlink/o...42125&ref_url=https%3A%2F%2Fwww.google.com%2F


----------



## morpheus620

what do you say about OPA1632 or OPA1637?


----------



## HiFan

HeyManslowdown97 said:


> Have you tried Opa2156? It too is CMOS audio amp. I plan on getting some soon!
> 
> ... I've actually used CMOS LDOs designed for audio ...



I have opa2156 sitting aside to be installed onto adapters. I have been a bit lazy but will try it out this weekend. 

In my collections, actually opa2228 isn't bad. I put it into one of my little DACs and use it for output. The warm presentation (due to higher 2nd harmonics distortion) pairs with my current Alessandro Ms Pro very well. I noticed no difference in details when comparing with opa2111. In the same position, opa1656 sounds flat with slightlty wider soundstage, but I feel sound is a bit weird (cannot properly discribe it).    

A side note on LDO. I recently have been probing and tweaking circuits using LM340/LM78xx. Their noise performance is medicore compared with many newer ones, but with oscilliscope I see it barely affects output noise level as opamps actually have ripple rejection. BUT, I found out that many devices were designed to use low ESR or high capacity output capacitors behind them, which is actually bad application. So I have been modding them to use 10uf tantalum output capacitors, and received positive results. According to application notes from TI, LDO output caps are only used to improve transient response of the LDO, and won't do any good to lower output ripple. Large caps actually will confuse the LDO's interal voltage differential error amp, and make LDO less responsive to voltage drop across the load.


----------



## HeyManslowdown97 (Jun 13, 2020)

HiFan said:


> l. I noticed no difference in details when comparing with opa2111. In the same position, opa1656 sounds flat with slightlty wider soundstage, but I feel sound is a bit weird (cannot properly discribe it).



Actually it makes a lot of sense. The opa2111 is one of 3 op amps that has Burr Brown “Bifet” design. The two others are opa2107 and opa627. However, it doesn’t sound like those two chips at all! It’s very musical imo.

You are not “wrong“ in describing the Opa1656, it is recommended to be used in portable devices I/V stage because it has a input fet like the opa1612 and the opa1642. It has to do with the load capacity limitation be under a certain load capacity of 50 ohms. (I believe).

Because Audio is mostly an AC application LDOs are used to allow current to travel via the circuit. I totally agree with you on the higher valued caps around them. They do stop the flow when the values are too high. Lots of people believe that the higher values in caps (everywhere in the DAC) increases VREF but that’s only true when the values are highest at the DAC chips in sigma delta modulator which are made mostly today in CMOS requirements are met. (R2R designs are be far more sophisticated and requires a lot of attention to details. They are simply an “art” to do with precision counterpointing resistance values and caps).

Personally, I am still “lost” when it comes to coupling caps with resistance series. That requires experiment “off board” but a lot of Sigma Delta modulators are pretty basic to implement, are cheap to make & also have their limits.


LDOs will ALWAYS produce noise (no question) but attempting to the lessen the noise, muzzle them or attempt to push the noise outside of the noise signal usually requires a cap of anywhere from 1-2uf ceramic caps based on data sheet recommendations so you can’t go “rogue” with the values.

Caps are all constructed differently and use different materials that often affect the sound. The same is true for resistors, Op Amps. The best are film caps because they do a great job filtering out DC noise which allows the audio signal to be stronger which are of lower values and are pretty large. Personally, I’m still trying to fully understanding coupling especially with caps and resistance.

The main objective always in 99% of all modding is the lower noise levels.

Since many DAC chips are CMOS like the AKM449X series it may make sense to use CMOS based parts like LDOs and Op Amps??? Because they sound better “natively” in short length circuits and power limits per sections of the DAC?? (not sure).

A lot of times you just have to wing it and take calculated risk or use threads to see if anyone has attempted what you are doing. As DIYERS we are not privy to endless R & D funding so a reliance on a community of hobbiest is parliament! A lot times, diyers in Audio proven methods for a problem aren’t totally scientifically proven but work. Haha


----------



## HeyManslowdown97

Rob43 said:


> Thanks, I'll take that into consideration...
> 
> 
> Rob43



Rob43,

Wanted to apologize, I want back a re-read you initial comment. At first, I mistook it as malice (which it wasn’t).

I do go on some tangent sometimes and can’t help it. Haha  

Sorry everyone for the double post, just wanted to get that in there.


----------



## HiFan (Jun 13, 2020)

HeyManslowdown97 said:


> Actually it makes a lot of sense. The opa2111 is one of 3 op amps that has Burr Brown “Bifet” design. The two others are opa2107 and opa627. However, it doesn’t sound like those two chips at all! It’s very musical imo.
> 
> You are not “wrong“ in describing the Opa1656, it is recommended to be used in portable devices I/V stage because it has a input fet like the opa1612 and the opa1642. It has to do with the load capacity limitation be under a certain load capacity of 50 ohms. (I believe).
> 
> ...



TBH, i do appreciate your input, but IME it is all decided by peripheral circuit rather than the opamp. To date I only roll in opamps that has similar reference design to avoid issues.

I have built several amp myself and got the chance to test out things extensively, including using recordings to check upon spectrum. It turns out my head is influencing my preception a lot more than the actual chip.

LDOs doesn't like ultra low esr ceramics in the output. You can use it in adj pin to stablize reading of the error amp, which actually is what determines the noise. It is going to resonate if you use that as output. TI has many writings on that. Here is an easy report.


----------



## HeyManslowdown97

HiFan said:


> LDOs doesn't like ultra low esr ceramics in the output. You can use it in adj pin to stablize reading of the error amp, which actually is what determines the noise. It is going to resonate if you use that as output. TI has many writings on that. Here is an easy



except I’m using ADI/LT LDOs Not TI


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## HiFan (Jun 13, 2020)

HeyManslowdown97 said:


> except I’m using ADI/LT LDOs Not TI



You still have to check datasheets. LT makes some chips based on similar designs of TI and onsemi. For example, LT1085/LM317/LM340 (these have on-semi counterparts) are actually "the same" chip. Most LDOs don't like ultra low esr in the output and they typically will specify what to use. I found 10uf Tantalum (non-smd type) to work very well.


----------



## HeyManslowdown97 (Jun 13, 2020)

HiFan said:


> You still have to check datasheets. LT makes some chips based on similar designs of TI and onsemi. For example, LT1085/LM317/LM340 (these have on-semi counterparts) are actually "the same" chip. Most LDOs don't like ultra low esr in the output and they typically will specify what to use.


Bro, they are CMOS. None of the ones you mentioned are!

Speaking from experience, I put 2.2 uf ceramic low ESR (It’s all I had) in the output and have NO issues! I do get what you’re saying though about DC issue. It depends how low they are.

https://www.analog.com/en/products/adp7142.html


----------



## HiFan (Jun 13, 2020)

HeyManslowdown97 said:


> Bro, they are CMOS. None of the ones you mentioned are!
> 
> https://www.analog.com/en/products/adp7142.html



According to datasheet, it doesn't help with noise but transient response, as I previosly mentioned. It seems the chip uses it only to save space, not because of its cmos input stage. On the other hand, DO NOT USE X5R as LT recommended, as they are subject to piezoelectric effects. Use NP0/C0G instead or organic polymers.

BTW, voltage of this is too low for me, I was looking for things that can output 16-32V. Dual rail supplu with +-15V sounds better to my ears than low voltage monorail 5V supply. 

Output Capacitor
The ADP7142 is designed for operation with small, space-saving
ceramic capacitors, but functions with general-purpose capacitors
as long as care is taken with regard to the effective series resistance
(ESR) value. The ESR of the output capacitor affects the stability
of the LDO control loop. A minimum of 2.2 μF capacitance with
an ESR of 0.3 Ω or less is recommended to ensure the stability of
the ADP7142.* Transient response to changes in load current is
also affected by output capacitance*. Using a larger value of output
capacitance improves the transient response of the ADP7142 to
large changes in load current. Figure 44 shows the transient
responses for an output capacitance value of 2.2 μF.


----------



## HiFan

HeyManslowdown97 said:


> Bro, they are CMOS. None of the ones you mentioned are!
> 
> Speaking from experience, I put 2.2 uf ceramic low ESR (It’s all I had) in the output and have NO issues! I do get what you’re saying though about DC issue. It depends how low they are.
> 
> https://www.analog.com/en/products/adp7142.html



Side note, even with LDOs that don't like low ESR caps, you can still use them after a small resistor (e.g. .0.33R) in series with LDO output pin. The only draw back is that this causes voltage to drop with current throughput, i.e 1A casues 0.33V drop. This is not good application for high current devices.


----------



## HeyManslowdown97 (Jun 13, 2020)

I wish I had space for organic polymers.

I could also tell that you were talking about larger voltage (just by the way you were talking). Then, you really, really have to pay attention!
It’s a portable music player and not my design and when your modding another persons design it’s hard to everything exactly like the Datasheets says.

You are correct in correcting me with ultra low esr in the output but what about the next caps it’s faces. That’s a joke.

The cap was already at 2.2 uf on the existing design (I measured it) so it was already stable. Was just messing with you.

My main point was that CMOS is being used more often and It’s interesting to me. I do believe the materials affect the sound


----------



## HiFan (Jun 13, 2020)

HeyManslowdown97 said:


> I wish I had space for organic polymers.
> 
> I could also tell that you were talking about larger voltage (just by the way you were talking). Then, you really, really have to pay attention!
> It’s a portable music player and not my design and when your modding another persons design it’s hard to everything exactly like the Datasheets says.
> ...



Modding exsiting design is difficult. True, hard on me to get my UD503 right.

When you have multiple caps in parallel, it is best to avoid paralleling low ESR caps. PCB has inductance, thus you are looking at possibility of C-L-C oscillation if you parallel low-esr caps. This is why film caps are typically avoided in power supply, as film has even lower ESR. In my amps, I typically use a 10uf tantalum as output cap, then will use a 47uf alu-cap for each power input of opamp.

Take Whammy amp for a better example, you can see it uses a resistor between all its input flter caps (3 on each rail)  to create a voltage differential, damping the caps and avoiding ripple "bouncing" back-and-forth between them.This is good practice when low esr caps are in parallel.


----------



## HeyManslowdown97

HiFan said:


> When you have multiple caps in parallel, it is best to avoid paralleling low ESR caps. PCB has inductance, thus you are looking at possibility of C-L-C oscillation if you parallel low-esr caps. This is why film caps are typically avoided in power supply, as film has even lower ESR. In my amps, I typically use a 10uf tantalum as output cap, then will use a 47uf alu-cap for each power input of opamp.


Yes, I learn this the hard way. When I first discovered the “power” of ultra low esr and went crazy putting everywhere until my player wouldn’t turn on. It took a month to  figure that one out once I took some out it worked again!

Used wisely, Ultra low ESR caps do wonders! Film caps are better but when space isnt issue.

I have an unrelated question but is about op amp outputs.

I have this Zishan DSDs and the output transitors are bjt can they swapped for jfets??

The reason is because I have some jfet op amps and since jfet is better with current noise, I figure (if it’s possible) to swipe them if it improves the output sound? 
The red circled area is what I’d like to swap the sod-123.


----------



## HiFan

HeyManslowdown97 said:


> I have this Zishan DSDs and the output transitors are bjt can they swapped for jfets??
> 
> The reason is because I have some jfet op amps and since jfet is better with current noise, I figure (if it’s possible) to swipe them if it improves the output sound?
> The red circled area is what I’d like to swap the sod-123.



I won't touch that. Transistors need to be manually matched for current. And, if you swapped to jfet, there is a high chance you also need to add gate stopper resistor to ensure stability. It's hard to do so with smd parts.


----------



## HeyManslowdown97

HiFan said:


> I won't touch that. Transistors need to be manually matched for current. And, if you swapped to jfet, there is a high chance you also need to add gate stopper resistor to ensure stability. It's hard to do so with smd parts.


Agreed on two parts one it is soooo frickin’ hard to match transistors and Jfets need a gate. This is what I read too but you know... wishful thinking is a helluva drug! 

I am beginning to believe that larger Audio systems it’s all about Voltage and portable is all about current!

When I first started op amp Rolling I never looked at datasheets and you know you listen and read about boutique amps than you get them and you don’t know why your battery life is half what was before.

Because portable is more about current than voltage op amp’s like the opa1692 are at times your best option in saving some. Of course when you have a larger power supply the world is your Oyster.

Often what’s around an op amp is more important than the op amp itself, it’s true but op amp Rolling is much fun.


----------



## HiFan (Jun 13, 2020)

HeyManslowdown97 said:


> Agreed on two parts one it is soooo frickin’ hard to match transistors and Jfets need a gate. This is what I read too but you know... wishful thinking is a helluva drug!
> 
> I am beginning to believe that larger Audio systems it’s all about Voltage and portable is all about current!
> 
> ...



I think it all depends on the designer. ESS chips output can be set to current mode and voltage mode, while AKM are voltage mode only (newer chips removed internal I/V converter for greater flexibility). So if the designer choose to build around a voltage signal circuit, he will be using fet a lot. Another thing about BJT devices is that they are expensive.

Portables are limited by their batteries so constant high current drain is unfavored, so you don't want to use current signal (since you need a certain amplitutde to raise SNR). I probably would just use a fet opamp and build a current source after it, and it is the same with your device's original design.

BTW, you have a fun device. I just don't like muses02 that much (hype IMO and it is very expensive). And, oh, opa1656 has a FET-input stage but uses a cmos process.


----------



## HeyManslowdown97 (Jun 13, 2020)

HiFan said:


> BTW, you have a fun device. I just don't like muses02 that much (hype IMO and it is very expensive). And, oh, opa1656 has a FET-input stage but uses a cmos process.



Haha. I am well aware of this and so do some bipolar like opa1612. That’s why it’s a good choice for this application. I’m aware of the opa1656 fet input. It’s sounds pretty good in the Zishan. Muse02 is in the stock of the ak4499 version, it’s not really a choice. I’ll be getting that toy this week in the mail after a long delivery delays b/c of Covid-19. (Something else to play with...already have some ideas to implement on it) 

I would never buy MUSE02 willy nelly because of the exact same reasons: hyped up and expensive.

To be fair never heard it but I doubt ill be blown away when I do...

The AKM newest Chip is current output and voltage input I believe.

“I probably would just use a fet opamp and build a current source after it, and it is the same with your device's original design.”

Yep, hands down the best approach I have found!


----------



## HiFan (Jun 13, 2020)

HeyManslowdown97 said:


> The AKM newest Chip is current output and voltage input I believe.
> 
> “I probably would just use a fet opamp and build a current source after it, and it is the same with your device's original design.”
> 
> Yep, hands down the best approach I have found!



I am aware that many think that way, especially that's on akm4499's datasheet (the only one from akm that has a current output). But it depends on output impedance, real current output stage will use higher output impedance to raise SNR, which 4499 doesn't have (akm does 64ohm as oppsoed to 774 ohm on ess9038q2m, and pcm1794 even has 2k ohms. ). AKM only puts that I/V conversion on the outside so you can choose what to use. 

However, it is exciting to see new designs that push the limit.


----------



## HeyManslowdown97

HiFan said:


> But it depends on output impedance, real current output stage will use higher output impedance to raise SNR, which 4499 doesn't have (akm does 64ohm as oppsoed to 774 ohm on ess9038q2m, and pcm1794 even has 2k ohms. ). But it is not difficult to convert that signal back to voltage with a resistor in series.
> 
> However, it is exciting to see new designs that push the limit.



Thanks for the feedback. I'm definitely gonna look into it. The output impedance is 10 ohms that can be easily changed. You can put a jumper to output stage however, if you take it to the floor or ”floor it” you MUST lower the RMS on your digital music files and make sure there aren't any quantization errors.

Delta Sigma Modulators aren’t really efficient it’s important to oversample correctly. These chips can do multi bit but it’s not the same as R2R bit perfect DACs. Also in the Zishan you don’t have the mediator chips AK4118 that’s in the datasheets. A well thought out modular chain when you have space and have mapped out all the kinks is the way to do it. The pre amps have that kind of space!  

Actually these Delta Sigma Modulators are quite pedestrian circuitry designed compared to the art form of R2R DACs. In those DAC resistance isn’t futile!





HiFan said:


> But it is not difficult to convert that signal back to voltage with a resistor in series.



How?? What’s the procedure to do this???


----------



## HiFan

HeyManslowdown97 said:


> Thanks for the feedback. I'm definitely gonna look into it. The output impedance is 10 ohms that can be easily changed. You can put a jumper to output stage however, if you take it to the floor or ”floor it” you MUST lower the RMS on your digital music files and make sure there aren't any quantization errors.
> 
> Delta Sigma Modulators aren’t really efficient it’s important to oversample correctly. These chips can do multi bit but it’s not the same as R2R bit perfect DACs. Also in the Zishan you don’t have the mediator chips AK4118 that’s in the datasheets. A well thought out modular chain when you have space and have mapped out all the kinks is the way to do it. The pre amps have that kind of space!
> 
> ...




The easy way will be using a resistor, as current flows through, voltage drops accordingly. But it’s possible to use chips like opa1612 to do it. The new 4499 is very flexible. 

Remember i mentioned a gate stopper ifyou want to change BJT transistor to FET one?


----------



## HeyManslowdown97 (Jun 13, 2020)

HiFan said:


> Remember i mentioned a gate stopper ifyou want to change BJT transistor to FET one?



One minute...(mind blowing) Eureka Moment

Next minute....(mind still blowing) and that explains the choice for MUSE02 since it’s a input fet dual bipolar like the opa1612.

oh, look at the way things come out full circle! Ha!

This opens up my entire universe! That’s some Zen stuff right there!


----------



## HiFan

HeyManslowdown97 said:


> One minute...(mind blowing) Eureka Moment
> 
> Next minute....(mind still blowing) and that explains the choice for MUSE02 since it’s a input fet dual bipolar like the opa1612.
> 
> ...


I hope this makes your life easier.
https://www.electrical4u.com/source-of-electrical-energy/


----------



## HeyManslowdown97 (Jun 13, 2020)

HiFan said:


> I hope this makes your life easier.
> https://www.electrical4u.com/source-of-electrical-energy/



Moral of the story: it’s so basic just let the circuit show you, what it wants and it needs!   Make the necessary changes and listen for feedback whether it’s better or worse!

Will read your article when I have a chance! I knew I was heading in the right path, I just didn’t know why certain things worked better on Zishan but I did use clues left on the board’s design and what thought about what was the mindset. Not much of a scientific approach though.


----------



## HeyManslowdown97

@HiFan 
but why did they add bjt transitors on the ak4497 and not a buffer stage?? It just seems like they were like “oh crap, we ran out of power, let’s add this?”

It still baffles me!


----------



## HiFan (Jun 13, 2020)

HeyManslowdown97 said:


> @HiFan
> but why did they add bjt transitors on the ak4497 and not a buffer stage?? It just seems like they were like “oh crap, we ran out of power, let’s add this?”
> 
> It still baffles me!



That’s the current source. The main opamp doesn’t output enough current as HP driver. Opa1656 and muses02 can only output about +-50ma, which is rather low. Normally chips Like tpa6120, 49600 can do 200-700ma. This is crucial for low impedance phones or planar that suck current. BJTs are better in these positions than FET. FETs are better as voltage followers.

The choice of using transistor to do this, however, is a flavor thing. Many people like the sound from output stage built with discreet components. These circuits typically have slight higher 2nd order harmonic distortion (compared with chip based drivers) thus they sound "warmer". I actually like it.


----------



## HeyManslowdown97 (Jun 13, 2020)

HiFan said:


> Many people like the sound from output stage built with discreet components. These circuits typically have slight higher 2nd order harmonic distortion (compared with chip based drivers) thus they sound "warmer". I actually like it.



me too! it’s really hard to match the transitors though and they can easily distort and sound colored! I’ve tried to replacing these bjts transitors & it’s really, really hard to get them stable! I supposed that these Chinese components have odd figures since they aren’t quality controlled. They are crafty but it’s not like buying a board from TI and their components. Chinese electronics are fun though. Haha

I always wonder why some op amp makers like Sparkos?? Op amps have those discrete “opened” components and I always figured that’s what made their sound signature. It also has to be painstakingly hard to get them stable during development.


----------



## HiFan

HeyManslowdown97 said:


> me too! it’s really hard to match the transitors though and they can easily distort and sound colored! I’ve tried to match these bjts transitors is really, really hard to get them stable!
> 
> I always wonder why some op amp makers like Sparkos?? Op amps have those discrete “opened” components and I always figured that’s what made their sound signature.



It’s mainly distortion profile. Sparkos are good to my ears. I have a pair of singles. However i think money should first go to better headphones. Difference from sparkos aren’t as big as changing headphones.


----------



## HeyManslowdown97 (Jun 13, 2020)

HiFan said:


> It’s mainly distortion profile. Sparkos are good to my ears. I have a pair of singles. However i think money should first go to better headphones. Difference from sparkos aren’t as big as changing headphones.



I agree. Some Chinese hifi makers are proving that you can killer headphones for cheap!

I got the planar T1s off ebay barely used and they are amazing for 100!

sadly,in the west Beats and airpods on crappy smartphone DAC is where the mainstream is at.

Also, Bass in everything is dominates the sound spectrum with by bloated bass in those crappy headphones.


----------



## DynamicDave

Hi,

What are the pros and cons of driving the opamp to class A.
Do different opamps require different value resistors for constant output current?
What can I expect from doing this?


----------



## HiFan (Jun 26, 2020)

DynamicDave said:


> Hi,
> 
> What are the pros and cons of driving the opamp to class A.
> Do different opamps require different value resistors for constant output current?
> What can I expect from doing this?



Check this out: https://tangentsoft.net/audio/opamp-bias.html

and this: https://www.audioasylum.com/audio/tweaks/messages/31186.html


----------



## DynamicDave

Thanks,  I'll check them out.


----------



## Shtruckk

Hello,

I have a topping dx7 pro and i want to replace the stock op-amps (LME 47920 - headphone amp socket).
I was thinking at some discrete op-amps (https://www.aliexpress.com/item/32936027509.html) or something from SPARKOS LABS. 
I'm open to any sugestions. 

Thank you in advance for your help.


----------



## HiFan

Shtruckk said:


> Hello,
> 
> I have a topping dx7 pro and i want to replace the stock op-amps (LME 47920 - headphone amp socket).
> I was thinking at some discrete op-amps (https://www.aliexpress.com/item/32936027509.html) or something from SPARKOS LABS.
> ...



Get an opa1612 and be done.


----------



## morpheus620

OPA 1656 or 1692 are also good.


----------



## Rob43

morpheus620 said:


> OPA 1656 or 1692 are also good.



Another vote for the OPA 1656, they sound really good !

After they burned-in they really opened up.


Rob43


----------



## NCSUZoSo (Jul 27, 2020)

dhruvmeena96 said:


> SS2590 by sparkos
> 
> Anybody tried their flagship op amp



2x SS2590 on an AudioJade Dual-DIP adapter, along with 2x Mill-Max ED58408-ND. This is shot inside of my heavily modded SMSL sAp-10. This balanced headphone amp originally used a SOIC-8 op-amp!

Personally, I recommend using the Mill-Max ED90603 or  ED11083-ND  for converting SMD to DIP-8. Sparkos Labs and Burson Audio, both sell their own takes on this adapter, if you'd like to consider theirs.




I have 

I am in the process of writing a review between the Sparkos Labs: SS2590, SS3601| Burson Audio's V4-SS, V5-OPA, V6-OPA "Classic" & "Vivid"| Orange Amplifications Dual-DIP Discrete and a handful of IC op-amps, like the AD797, AD8597, LME4971 plus a few others.

You can find more info in the links below.

I was trying to get this done in July, but due to various reasons I had to push it back (Aug or Sep). I will be delivering a wide range of technical measurements in this review. I will try to keep it as objective, as I possibly can. Due to the large number of units to test, it is going to take a while, this is a one man show!

https://hallmanlabs.com/2020/07/20/discrete-review-update-isoregen-over-troubled-dip8-waters/

https://hallmanlabs.com/2020/06/03/sparkos-labs-pro-series-ss2590-discrete-op-amps/


----------



## sorrowdragon (Aug 11, 2020)

lol @ 20m30s


It's always interesting to see an opamp that comes up on these forums time to time, discussed from the perspective of a professional electrical engineer in regards to its design and breaking down it's performance on an electrical engineering/circuit design level rather than on the level of amateur audiofoolery who have no real idea or clue how opamps really work or know what any of those numbers they see on the spec sheets that they parrot out of their mouths but have no real understanding or comprehension of what those numbers really mean.


----------



## Audio Addict

Anyone with experience using the NewClassD Ultimate Edition opamps compared to the Sparkos Labs?


----------



## seamon

Is V5i still the best op amp if you need low profile?


----------



## seamon

So I'm going to maybe put Buron V5i in the I/V and LPF stage of my DAC, and amp stage of my amp. What's the best opamp for the Output Buffer Stage of the amp. It has BUF634A stock, is there anything better?


----------



## seamon

Alright for my DAC, I am thinking 2xMUSES01 for I/V and 2xMUSES03 for LPF


----------



## HiFan (Aug 11, 2020)

sorrowdragon said:


> lol @ 20m30s
> 
> 
> It's always interesting to see a discussion of an opamp that comes up on these forums time to time, however rather than from the perspective from an audiofool, from the perspective of a professional electrical engineer in regards to its design and breaking down it's performance on an electrical engineering/circuit design level rather than an amateur audiofoolery level who have no real idea or clue how opamps really work.




He is right technically but that's not all that's going on. You have to pay attention to technical backgrounds that his ideas were built upon. Not every chip works the same in a specfic circuit, ie circuit built for BJT will probably have more voltage noise than that built for FET. So if you swap opamps the other way, it might not be as good. Sometimes people use high speed opamps in circuits that doesn't have enough feedback. Sometimes it is just one chip worse than anothe, or has less current output under specific load.

And ultimately, people don't always appreciate the sound of higher spec ss circuits. I am currently using a garage1217 with opa1612 and enjoy it a lot better than o2. I built mine (actually got two) and got to play with all sorts of parameters including ESR of capacitors.

Just keep in mind that when it comes to technical info, properly using these chips is very complicated. If you try to summarize it in a few lines, you must have overlooked a lot of things.


----------



## mhhd

Alternative for OPA2210 - Suggestion needed

Dears,
Unfortunately I had to replace the 4 OPA2210 that I swapped into the gain section of my Keces S3 Dac/preamp (bypass caps in place). They "produced" some hum. The opamps themselves were ok, as verified by an Keces electronics workshop. 
So now they are substituted by what was on hand, OPA2604, and the unit works properly again. But of course sound-wise it is quiet a step back.
Did some of you make similar experience? Any recommendation for a less sensitive opamp as OPA2210 but with similar exceptional performance?

Thank you very much for all comments and recommendations 

Rgds,
Martin


----------



## mhhd

HeyManslowdown97 said:


> I have ADA4610-2, ADA4637-1and ADA4625-2 in the ADA46** series
> 
> A lot of DIY audio community compares them to the famous Burr-Brown JFETS Opa627 and Opa637.
> 
> ...



Thanks for your detailed describtion! Regarding ADI, I experienced great support from them, even for an amateur like me. They simulated some transient response charts that were missing on the data sheet for ADA4610. I attached them for whom it may be helpful.
Rgds,
Martin


----------



## redrol

seamon said:


> Is V5i still the best op amp if you need low profile?


I like the Muses02 slightly more due to its sort of richer sound.  The V5i is my next pick.  Leaps and bounds above all the OPAs imo.  The Muses02 though... <3


----------



## seamon (Sep 23, 2020)

redrol said:


> I like the Muses02 slightly more due to its sort of richer sound.  The V5i is my next pick.  Leaps and bounds above all the OPAs imo.  The Muses02 though... <3


Since nobody replied, I decided to just try all high end integrated opamps(MUSES01, MUSES02, MUSES03, AD827SQ, Burson V5i and AD797) myself and see what sounds best to me.

I found that AD797 is the holy grail of opamps and sounds better than pretty much anything else by a large margin. However, it is a very finicky opamp and might not work for all circuits.

I am now selling all my MUSES and Burson opamps here.


----------



## Jimmy24

Seamon, you may need to try the OPA627. I've tried MUSES 01/02 and wasn't impressed with them as I was with the 627


----------



## seamon

Jimmy24 said:


> Seamon, you may need to try the OPA627. I've tried MUSES 01/02 and wasn't impressed with them as I was with the 627


https://www.head-fi.org/threads/aud...viewed-opa-earth-opa-moon-opa-sun-v-2.397691/

I was referring to this post and it says AD797B is better than 627. Seems to be a lot of good info here. I have AD797ANZ rn and I just ordered custom AD797BRZ.


----------



## leeperry

seamon said:


> https://www.head-fi.org/threads/aud...viewed-opa-earth-opa-moon-opa-sun-v-2.397691/
> 
> I was referring to this post and it says AD797B is better than 627. Seems to be a lot of good info here. I have AD797ANZ rn and I just ordered custom AD797BRZ.


A lot has happened in 11 years ^^

try OPA1622 & OPA828


----------



## seamon

leeperry said:


> A lot has happened in 11 years ^^
> 
> try OPA1622 & OPA828


The DAC and AMP came default with OPA1612 and OPA1611. I think they sound very clinical and analytical. I don't like their sound signature. Is the OPA1622 better?


----------



## leeperry

OPA1611 is just OPA211 with a new number FWIR and I don't like either at all.


----------



## seamon

leeperry said:


> OPA1611 is just OPA211 with a new number FWIR and I don't like either at all.


I might try out the OPA1622. Currently I have the AD797ANZ and it sounds amazing, waiting on AD797BRZ on Browndogs.

Also as per your post from a decade ago, I tried LT1028ACN8 in the LPF section of the DAC, I thought it was not as good as the AD797ANZ.


----------



## leeperry

AD797 and OPA627 cannot be rolled blindly, they need a specific circuit built for them. They'll oscillate and/or sound way colored.

OPA828 is the newest 627, cheap too coz 627's on marketplaces are 99.999999% fake and genuine 627BP's cost a bundle.


----------



## seamon

leeperry said:


> AD797 and OPA627 cannot be rolled blindly, they need a specific circuit built for them. They'll oscillate and/or sound way colored.
> 
> OPA828 is the newest 627, cheap too coz 627's on marketplaces are 99.999999% fake and genuine 627BP's cost a bundle.


Yes I knew that and rolling in the AD797ANZ was a gamble. However, the AD797ANZ sounds very good in my setup. So I suppose I won the gamble?


----------



## leeperry

Nah it most likely oscillates in the Mhz range and will sound way colored to some extent.


----------



## seamon

leeperry said:


> Nah it most likely oscillates in the Mhz range and will sound way colored to some extent.


To me the AD797ANZ sounds more transparent than MUSES, Burson, OP1611 and AD827SQ


----------



## seamon

leeperry said:


> Nah it most likely oscillates in the Mhz range and will sound way colored to some extent.


Hello again!
So just for some reference, I am trying to change the opamps in 3 different stages - I/V stage for 9038 Pro(accepts 2xDual) + LPF stage(Accepts 1xDual or 2xSingle) + Amp stage(Accepts 4xSingle or 2xDual).

On the Amp stage, AD797 sounds extremely transparent. On the LPF stage, I think there might be some oscillations but it sounds better than anything else. On the I/V stage, it's unusable because of heavy oscillations.

I am thinking of trying out the OPA1622 now. 
1) Do you think it's good for all stages(I/V, LPF and Amp)?
2) What's a good source to buy OPA1622 in Dip8 sockets?


----------



## mhhd

Mad Max said:


> I haven't had any bad experience with Cirrus Logic DACs myself.  The only DACs that I've really disliked are just those ESS DACs.  Disgusting sound.
> I still prefer BB, AKM, and ADI, which are still common.  AKM sure is popular these days.
> I had not tried PCM1795 until the Teac P90 and FiiO E18.  Wow, what beautiful sound.
> 
> Also, forgot to recommend ADA4001 over ADA4004.  4001 is uber transparent, more than most opamps.  Specified for mic preamps, and I can hear why it would rock hard in such, especially in recording gear.


Hello Max,
Coming back to this older post  Were you ever able to compare ADA4001 to ADA4610? Or to one of the better OPAs? Could you describe the differences you experienced?
Thank you very much,
Martin


----------



## seamon

Tried the OPA1622. It's disappointing. AD797 is better in the amp gain stage. OPA1612 is better in the I/V and LPF stage.


----------



## mhhd

HiFan said:


> I run opa1656 in my modded HA21. It partially depends on your circuit and some doesn't make opamps sound drastically different.
> 
> I think 1656 is better than 1692 in my gear. OPA2210 is also a good chip if it works.


Hello,
Did OPA2210 not work porperly? I ask as OPA2210 was very noisy in my application. So maybe the opamp is sensitive...?
Thanks a lot


----------



## Audio Addict

Has anyone tried the Sonic Imagery Labs 990 Enh

https://www.sonicimagerylabs.com/products/Model990Enh-Ticha.html


----------



## madnanny1

Ashkii21 said:


> I've built a couple of Cmoys, so my knowledge of opamps is limited.
> 
> 
> 
> ...


Hello out there i have an acmee mf01 and wonder if anyone has tried replacing opamp with a burson v5i,cant find any info on this on internet. Can anyone help me thanks


----------



## redrol

madnanny1 said:


> Hello out there i have an acmee mf01 and wonder if anyone has tried replacing opamp with a burson v5i,cant find any info on this on internet. Can anyone help me thanks



Hey bro, I did this and its awesome!!! I love it.  Nice difference from the Muses02 that it has.  Highly recommended!!  Bit more microdetails imo, slightly less warm but VERY nice.


----------



## redrol (Oct 7, 2020)

Peak opamp?  Not sure
Sparkos  SS2590 x2 w/ Xduoo 05+



First impressions are of course amazing.  No really, damn, damn damn.  I doubt I'll be able to like anything after this thing.  It's got ALL the attributes I love. Just everything.. out of words


----------



## madnanny1

redrol said:


> Hey bro, I did this and its awesome!!! I love it.  Nice difference from the Muses02 that it has.  Highly recommended!!  Bit more microdetails imo, slightly less warm but VERY nice.


Hello thanks for your reply,have a burson on order.what.headphones do you use ? I have. Sennheiser px100 mk 1 and 2,he150 pro .tried sennheiser hd599,very disappointed with sound my px100 sounded better,sent them back.also have monk and soundmagic e10 plus auglamour rx1


----------



## redrol

I don't use headphones much but I do use the Shuoer EJ07, Tanchjim Oxygen, and a few others daily.


----------



## Merlin-PT (Jan 15, 2021)

Today I decided to open the lid of some AliExpress opamps with a pair of pliers.
In 10xOPA627 SOP8 (bought used at 0.97eur each), I opened the 3 burned ones and was lucky. They are genuine.
There's no more stock so I couldn't buy more.



Spoiler: Mobile phone photo of DIE with 3,66eur 100x plastic microscope.


----------



## redrol

well holy crap dude!  RIGHT ON!


----------



## Merlin-PT (Jan 15, 2021)

.


----------



## Audio Addict (Oct 17, 2020)

Has anyone bought any opamps pre-installed on adapters from

https://www.cimarrontechnology.com/product-category/single-channel-op-amps

https://www.cimarrontechnology.com/product/browndog-970601-so8-to-dip8-adapter

They have both single and dual available.


----------



## Magic77

Audio Addict said:


> Has anyone bought any opamps pre-installed on adapters from
> 
> https://www.cimarrontechnology.com/product-category/single-channel-op-amps
> 
> ...


Yes, I have ordered from them before. They are very good. The chips are perfectly soldered to the adapters. I never had a problem with their services.


----------



## seamon

leeperry said:


> AD797 and OPA627 cannot be rolled blindly, they need a specific circuit built for them. They'll oscillate and/or sound way colored.
> 
> OPA828 is the newest 627, cheap too coz 627's on marketplaces are 99.999999% fake and genuine 627BP's cost a bundle.


OPA828 was a great call. They sound amazing. They have quickly become my new favorite opamp. Thanks!!!



Audio Addict said:


> Has anyone bought any opamps pre-installed on adapters from
> 
> https://www.cimarrontechnology.com/product-category/single-channel-op-amps
> 
> ...


I have ordered $350+ worth of opamps from them. Great service.


----------



## loller (Oct 31, 2020)

Hello everybody, just one question.. I don't know how easy it will be to answer but I hope to be helped by somebody.. Prepare yourself for a jump in the past because I haven't updated my gear in a long time:
I am currently using a pair of sennheiser hd598 connected to a xfi elite pro (that I think has a JRC NJM4556) and drived by a cmoy bb (altoids amp) that inside has an OPA2227.
Now I'm questioning if it is better to disconnect the cmoy and connect directly the headphones to the external bay of my audiocard..
I've tryied for a short time and honestly I haven't fond a lot of difference (directly from the xfi bay I hear more bass) but don't know what is the best. could you help me?
and maybe suggest me some way to test the audio quality (maybe some music that will be helpful)

thank you


----------



## redrol

(smallest bestest opamp swapping mobile package)


----------



## Setmagic

Hello I just bought my first opa from AliExpress with good reviews. But I'm not 100% sure if it's original. OPA1612


----------



## domiji

Shtruckk said:


> Hello,
> 
> I have a topping dx7 pro and i want to replace the stock op-amps (LME 47920 - headphone amp socket).
> I was thinking at some discrete op-amps (https://www.aliexpress.com/item/32936027509.html) or something from SPARKOS LABS.
> ...



Did you change your op amps in your DX7 pro?

I saw this Video:


And he is rec the Sparkos SS3602.
I think to try these or the Burson V6.


----------



## domiji

Hello op amp specialists 

I would like to change the op amps in my Topping DX7 pro and i picked the Burson V5i just because they fit out of the box (the V6 wouldn't).
Originally the DX7 pro is equipped with LME47920 and in the LPF section LME49720.

Are these the right ones to go with?
https://www.audiophonics.fr/en/comp...mp-v5i-dual-opa-hybrid-dip8-pair-p-13152.html

Shoul i also change the op amps in the LPF section doesn't this really matter at all?

Thanks for you help


----------



## Shtruckk

I didn't change the op amps, my first option will be the sparkos, but the for the moment they are too expensive for me, I hope next year..


----------



## domiji

I've heard that the SparkOS are very bright sounding i thought that the Burson V5is could deliver a more smooth and warmth sound signature.


----------



## docentore

Seriously, you might be disappointed. LME49720 is one of the best (mass manufactured) op-amps of all times. Old is gold


----------



## domiji

So you wouldn't change the OP Amps in the DX7 pro?


----------



## seamon (Dec 10, 2020)

domiji said:


> So you wouldn't change the OP Amps in the DX7 pro?


In their D90 DAC, they have soldered the LME49720 for LPF, I guess a testament to how well this particular opamp suits their deigns. Topping seems to be doing OPA1612 for I/V and LME49720 for LPF for all their DACs. I was considering doing some rolling in my D50s but I think I will leave the LME49720 in.

Edit: Also SS3602 does not fit the D50s. SS3602 is the only opamp I feel comfortable with swapping blindly in.


----------



## domiji

I've already ordered the Bursons V5i and will try them on monday   

Maybe i order some SS3602 anyway just for fun. I only use the DX7 pro as my headphone amp so i only have to buy 2 of them and it's not too pricy


----------



## tmb821

I was able to try the v6 vivid dual opamp out in my topping nx3s. All I can say is wow! It really opens up the soundstage. Everything got wider and I felt as if I could hear where each of the instruments were coming from. And it moved the singers voice just in front of me. The crispness it added to the treble and bass was incredible. The detail and clarity were amazing as well. This is all in comparison to the venerable ne5532 opamp which has been my favorite to this point. Unfortunately, this opamp is not practical for me. As you can see from the pictures you absolutely cannot have the amps case on and use this opamp. I really wish I could have fit it in my xDuoo XD05 plus, but it wouldn’t fit at all, even with the included spacer.  If I had a desktop amp that I could use this one in I would in a heartbeat.


----------



## Sam Spade

tmb821 said:


> I was able to try the v6 vivid dual opamp out in my topping nx3s. All I can say is wow! It really opens up the soundstage. Everything got wider and I felt as if I could hear where each of the instruments were coming from. And it moved the singers voice just in front of me. The crispness it added to the treble and bass was incredible. The detail and clarity were amazing as well. This is all in comparison to the venerable ne5532 opamp which has been my favorite to this point. Unfortunately, this opamp is not practical for me. As you can see from the pictures you absolutely cannot have the amps case on and use this opamp. I really wish I could have fit it in my xDuoo XD05 plus, but it wouldn’t fit at all, even with the included spacer.  If I had a desktop amp that I could use this one in I would in a heartbeat.


Have a look at the sparko op amps. They are flatter and might fit.


----------



## docentore (Dec 11, 2020)

domiji said:


> So you wouldn't change the OP Amps in the DX7 pro?


I've learned that sometimes the op-amp originally used in dac/amp is good enough and blindly swapping them doesn't bring any gain.
There are exceptions, of course. But what I mean is that the LME49720 is VERY good op-amp. I know the design is few years old but look at the Muses line - it is about same age (designed in 90's or ealry 2000's afaik) but still one of the best choices.




Sam Spade said:


> Have a look at the sparko op amps. They are flatter and might fit.



You wont be able to close the case with Sparkos anyway.


----------



## seamon

docentore said:


> I've learned that sometimes the op-amp originally used in dac/amp is good enough and blindly swapping them doesn't bring any gain.
> There are exceptions, of course. But what I mean is that the LME49720 is VERY good op-amp. I know the design is few years old but look at the Muses line - it is about same age (designed in 90's or ealry 2000's afaik) but still one of the best choices.
> 
> 
> ...


The M in Muses stands for Marketing. The Muses lineup is one of the worst sounding opamps of them all. Muses are all colored opamps, they change the sound in a significant way. If you are after transparency, avoid the Muses opamps imo. Muses opamps also have abysmal noise ratings.


----------



## docentore

seamon said:


> The M in Muses stands for Marketing. The Muses lineup is one of the worst sounding opamps of them all. Muses are all colored opamps, they change the sound in a significant way. If you are after transparency, avoid the Muses opamps imo. Muses opamps also have abysmal noise ratings.


Agree on the coloured part. I find Muses02 to be coloured but musical. Using 2x8920 in my modified ibasso amp1 module, and either these are more on the neutral side or the implementation in amp module doesn't show their character, coloured or not 
Haven't heard the rest.

But I know LME49720 and if there was hall of opamp fame one has to agree that it would be there (or 4562 or 49860). That was the point in my post 

Thanks for the advice, I'll give rest of M series a miss.


----------



## seamon

docentore said:


> Agree on the coloured part. I find Muses02 to be coloured but musical. Using 2x8920 in my modified ibasso amp1 module, and either these are more on the neutral side or the implementation in amp module doesn't show their character, coloured or not
> Haven't heard the rest.
> 
> But I know LME49720 and if there was hall of opamp fame one has to agree that it would be there (or 4562 or 49860). That was the point in my post
> ...


Muses01 is the most uncolored and has the lowest noise. Muses02 is warm and is the noisiest. Muses03 has a focus on the midrange with an abysmally bad treble.


----------



## docentore

seamon said:


> Muses01 is the most uncolored and has the lowest noise. Muses02 is warm and is the noisiest. Muses03 has a focus on the midrange with an abysmally bad treble.



Any thought of 8820 Vs 8920? 
Any thoughts on finding upgrade to OPA1642?


----------



## seamon

docentore said:


> Any thought of 8820 Vs 8920?
> Any thoughts on finding upgrade to OPA1642?


Haven't heard any one of those. Try AD797B or OPA828


----------



## docentore

seamon said:


> Haven't heard any one of those. Try AD797B or OPA828



Thanks. Both are single opamps.

I'm looking replacement for opa1642, jfet dual opamp in soic8 case.


----------



## seamon

docentore said:


> Thanks. Both are single opamps.
> 
> I'm looking replacement for opa1642, jfet dual opamp in soic8 case.


You can get them made for Dual channel here:
https://www.cimarrontechnology.com/product/browndog-020302-single-to-dual-op-amp-adapter

Also try OPA1656 and OPA1622


----------



## docentore

seamon said:


> You can get them made for Dual channel here:
> https://www.cimarrontechnology.com/product/browndog-020302-single-to-dual-op-amp-adapter
> 
> Also try OPA1656 and OPA1622


Yes but you can't solder browndog onto PCB directly in place of soic ic 

I'll try 1656, heard good things about it.


----------



## seamon

docentore said:


> Yes but you can't solder browndog onto PCB directly in place of soic ic
> 
> I'll try 1656, heard good things about it.


*Ahem*
https://www.cimarrontechnology.com/product/browndog-031101b-dip8-to-so8-adapter

Seriously though, I missed the SOIC part


----------



## domiji

Burson V5i arrived a few minutes ago and they sound fantastic so far. Sound is much more smoother and pleasing with the DX7 Pro 

Am i correct that the LPF Section in the DX7 Pro is just for Line Out?


----------



## seamon

domiji said:


> Burson V5i arrived a few minutes ago and they sound fantastic so far. Sound is much more smoother and pleasing with the DX7 Pro
> 
> Am i correct that the LPF Section in the DX7 Pro is just for Line Out?


My problem with V5i is the boomy and loose bass, just ruins bass for me


----------



## domiji

seamon said:


> My problem with V5i is the boomy and loose bass, just ruins bass for me



I will compare them tomorrow with the V6 Classics


----------



## domiji

seamon said:


> My problem with V5i is the boomy and loose bass, just ruins bass for me



After a few hours of listening i guess i know what you mean. I will try the V6 Classic tomorrow. They should sound completely different from the V5i. 

But i think i also have to order the SparkOS 3602


----------



## Merlin-PT (Dec 14, 2020)

Setmagic said:


> Hello I just bought my first opa from AliExpress with good reviews. But I'm not 100% sure if it's original. OPA1612



I bought 2 from 2 different Aliexpress sellers and also would like to know what they are.
Outside they look like yours, with exception of having different numbers bellow 1612A.
I removed the die from both of them and they had the same die.

I only have a 3eur toy microscope, so I can't zoom more and couldn't find any identification:


Spoiler


----------



## Audio Addict (Dec 14, 2020)

I recently bought the 1612s from

https://www.cimarrontechnology.com/

https://www.cimarrontechnology.com/product/texas-instruments-opa1612aid-dual-channel-op-amp

Which are the SOIC version mounted on DIP adapters and they don't look like that.  Which versions are those?


----------



## Merlin-PT (Dec 14, 2020)

Those on @Setmagic photo and the ones I bought on AliE are soic.
They look like these random googled photos:
http://eng.soomal.com/epic/10100000241.htm
https://www.head-fi.org/threads/the-opamp-thread.432749/page-387#post-14076785
Could you elaborate on the differences or post a photo?


----------



## Audio Addict (Dec 14, 2020)

Here are what I received.











Maybe they are the same.  I could not read anything on them until I took the picture.


----------



## Merlin-PT (Jan 15, 2021)

The markings look identical, this is good, but imo not conclusive.
I prefer to always buy from official distributors. I got these from AliEx to open them.
The die photos look pretty and my idea was to look inside to see what was there, but I have nothing to compare this one. 
It was easy to open the IC and remove the die, I tried this recently.
If anyone wondering, I followed this process with hot air station (do use safety glasses):


Spoiler


----------



## saeid72 (Dec 24, 2020)

Hi
I have an Objective 2 ( O2). Op amp Stock is 1X NJM2068 input and 2X NJM4556 output . Sound is full Natural and Transparent
I am Replaced NJM2068 to OPA2134 . The sound is a very little warmer and very little more bass but Soundstage is narrow than stock NJM2068 and And the mids looks in the face Compared to NJM2068 . I do not like the sound. Sound stage is important to me. NJM2068 not any colored and very balance but less Fun and No signature

I want to buy a OPA2107 and a LM4562 for output op amp. Can two different models be used for op amp output? Or do I just have to replace the same model (x2) for output stage? If not. Is there a logical reason?
Does buying 2x new Op amp (output stage) have a good audible effect? My expectations of the stock sound: Warmer sound (More bass. fuller Mids . Warm treble) and bigger sound stage than stock. ( Complete positive changes Without any sound worse than stock Objective 2 AMP)

Which has the most impact on the sound ( Output stage or Input stage?? )
I live in Iran. OPA2134. OPA2107. LM4562. AD8620. Available. At a very high price: $30 to $40. Also available NE5532 very cheap $1
Op amp Models with higher numbers but less known and popular. Very cheap to buy.( For example LM4562 and AD8620 $30 to $40 and LM4890 and AD8692 only $2). Are they worth buying? Higher model numbers and drastically lower prices. Good sound or not for Audiofile HIFI?
I will be grateful. If you know the answers to these questions, please help


----------



## saeid72 (Dec 24, 2020)

saeid72 said:


> Hi
> I have an Objective 2 ( O2). Op amp Stock is 1X NJM2068 input and 2X NJM4556 output . Sound is full Natural and Transparent
> I am Replaced NJM2068 to OPA2134 . The sound is a very little warmer and very little more bass but Soundstage is narrow than stock NJM2068 and And the mids looks in the face Compared to NJM2068 . I do not like the sound. Sound stage is important to me. NJM2068 not any colored and very balance but less Fun and No signature
> 
> ...


I'm back to NJM2068 stock objective 2 . WOW. Wide Soundstage very bigger than OPA2134. Less bass. Mids Transparent and very deep. no like OPA2134 Sticking to the ear hole. Treble Transparent without warm like OPA2134. Sound Overall not cold but Absolutely superior OPA2134
OPA2134 Like garbage. With these conditions, I probably do not like OPA2107? OPA2107 Is it close to 2134? Maybe I should be completely carefree. How about LM4562? Any suggestions?
Someone answer faster. Thanks


----------



## saeid72 (Dec 26, 2020)

saeid72 said:


> I'm back to NJM2068 stock objective 2 . WOW. Wide Soundstage very bigger than OPA2134. Less bass. Mids Transparent and very deep. no like OPA2134 Sticking to the ear hole. Treble Transparent without warm like OPA2134. Sound Overall not cold but Absolutely superior OPA2134
> OPA2134 Like garbage. With these conditions, I probably do not like OPA2107? OPA2107 Is it close to 2134? Maybe I should be completely carefree. How about LM4562? Any suggestions?
> Someone answer faster. Thanks


I bought a LM4562. I will get it tomorrow. Now I'm in stock (1x NJM2068 input and 2x NJM4556 output)
But today I replaced 1 of NjM4556 output with OPA2134 . Yes! 2 different amps at the output stage. No one has ever done this before. it works. It is possible. it's interesting
Now I have a better sound. The OPA2134 has completely left its mark.
Strong bass. Warm Treble. Forward midrange (but not as bad when OPA2134 on input stage) Less soundstage (but not as narrow as when OPA2134 in input stage)
The sound is completely mixed. Two different op amp affect the output stage 50/50 each. Maybe this OPA2134 will replace one of NJM4556 forever. But it still has a really negative impact on the sound stage. soundstage OPA2134 It is a complete disaster. When OPA2134 in the input stage. Tragedy. Absolutely no sound stage


----------



## Sam Spade

saeid72 said:


> I bought a LM4562. I will get it tomorrow
> But today I replaced 1 of NjM4556 output with OPA2134 . Yes! 2 different amps at the output stage. No one has ever done this before. it works. It is possible. it's interesting
> Now I have a better sound. The OPA2134 has completely left its mark.
> Strong bass. Warm Treble. Forward midrange (but not as bad when OPA2134 on input stage) Less soundstage (but not as narrow as when OPA2134 in input stage)
> The sound is completely mixed. Two different op amp affect the output stage 50/50 each. Maybe this OPA2134 will replace one of NJM4556 forever. But it still has a really negative impact on the sound stage. soundstage OPA2134 It is a complete disaster. When OPA2134 in the input stage. Tragedy. Absolutely no sound stage


Those 2 op amps arent on different channels are they?


----------



## saeid72

Sam Spade said:


> Those 2 op amps arent on different channels are they?


No, I do not think they are separate. Both amps of the output stage phase work in parallel. They are not separate. My amp is objective 2. As far as I know. x2 op amp on output stage phase work together. Not separated
According to the manufacturer :
http://nwavguy.blogspot.com/2011/08/o2-details.html


----------



## Sam Spade

saeid72 said:


> No, I do not think they are separate. Both amps of the output stage phase work in parallel. They are not separate. My amp is objective 2. As far as I know. x2 op amp on output stage phase work together. Not separated
> According to the manufacturer :
> http://nwavguy.blogspot.com/2011/08/o2-details.html


Okay just asking a dumb question. In my burson C3X ref  i have 4 op amps. Two pairs, one pair in the IV stage and one pair in the LP stage. In each pair there is one per channel. Burson say it's fine to have different op amps in each stage but the pairs of R+L should be the same. If they were different it would still work i think but you wouldn't want to have different sounding channels. 

What device are you modding?


----------



## Sam Spade

Oh i looked at your link. Thats really  cool 😄


----------



## saeid72 (Dec 26, 2020)

Sam Spade said:


> Okay just asking a dumb question. In my burson C3X ref  i have 4 op amps. Two pairs, one pair in the IV stage and one pair in the LP stage. In each pair there is one per channel. Burson say it's fine to have different op amps in each stage but the pairs of R+L should be the same. If they were different it would still work i think but you wouldn't want to have different sounding channels.
> 
> What device are you modding?


Exactly right. This makes perfect sense. An amp with 1 output channel. Logically, the same amp should be used. But I used two different models. I wanted to test and I was fascinated. I wondered why no one tried it. But the results were great for me. There really is no disharmony or distortion or delay or distance. Problems may appear with accurate measurements and on paper. But there is nothing wrong with listening to my precise ears. Only the color and mood of the OPA2134 added. I'm thinking of doing a triple combination(LM4562 OPA2134 AD8620) Three kinds of sound and three companies. It seems like a dream
my device: Objective 2 amp (Amp discussed) + Schiit modi dac + Akg Q701 Headphone




Sam Spade said:


> Oh i looked at your link. Thats really  cool 😄


Grand Master nwavguy. Only on paper and measure . No belief in Listen


----------



## saeid72 (Jan 14, 2021)

saeid72 said:


> I bought a LM4562. I will get it tomorrow. Now I'm in stock (1x NJM2068 input and 2x NJM4556 output)
> But today I replaced 1 of NjM4556 output with OPA2134 . Yes! 2 different amps at the output stage. No one has ever done this before. it works. It is possible. it's interesting
> Now I have a better sound. The OPA2134 has completely left its mark.
> Strong bass. Warm Treble. Forward midrange (but not as bad when OPA2134 on input stage) Less soundstage (but not as narrow as when OPA2134 in input stage)
> The sound is completely mixed. Two different op amp affect the output stage 50/50 each. Maybe this OPA2134 will replace one of NJM4556 forever. But it still has a really negative impact on the sound stage. soundstage OPA2134 It is a complete disaster. When OPA2134 in the input stage. Tragedy. Absolutely no sound stage


I got the LM4562
Comparison LM4562 vs OPA2134 vs NJM2068 vs NJM4556
LM4562: Strong bass . Warm Mids (Deep and Full) . Treble with a bit Warm . Wide soundstage
OPA2134: Strong bass . Very forward Mids . Treble  Fully warm and back. Narrow Soundstage
NJM2068: Weak bass . Natural Mids (Thin and unchanged) . cold Treble (Natural) . Good Soundstage
NJM4556: Natural bass . Good Mids (Warmer and deeper than NJM2068) . Treble with a bit Warm. Good soundstage
LM4562 > NJM4556 > OPA2134 > NJM2068
LM45562 Winner. Now the reason for the great popularity of the LM4562 has become clear
====================================================================
I also like to try the AD8620 (for the famous sound sound stage) but I think maybe it has a cold sound? Also make the OPA2107. But I guess it should not be much different from the OPA2134? (Probably just a little better sound stage)


----------



## Distorted Vision (Dec 30, 2020)

I'm looking to upgrade the opamps in my Xduoo XD-5 and Aune X8 which both still have the stock ones.
I am looking at the Burson V5i-D and Muses02. How do these opamps compare? Which others should I consider for my devices? I am only interested in opamps which fit the respective cases. I have a XP3 PSU for the X8. 

I listen to mostly electronic music.

Many thanks!


----------



## saeid72

Distorted Vision said:


> I'm looking to upgrade the opamps in my Xduoo XD-5 and Aune X8 which both still have the stock ones.
> I am looking at the Burson V5i-D and Muses02. How do these opamps compare? Which others should I consider for my devices? I am only interested in opamps which fit the respective cases. I have a XP3 PSU for the X8.
> 
> I listen to mostly electronic music.
> ...


Analog devices more bass than other op amp (AD8066 , AD8620). Burson V5i-D and Muses02 are very good But balanced sound not heavy bass. Burson V5i-D better than OPA1612 stock Xduoo XD-5


----------



## fabio19

raoultrifan said:


> Hi,
> 
> LME49710 is single opamps, while OPA1622 and OPA1692 are dual-opamps.
> Probably OPA1611 would be a good choice. AD797 could be tested too.
> You might also try BURSON SS V6 Classic/Vivid, though the price is a bit high maybe.



Better OPA 1611 or OPA 1622?


----------



## raoultrifan

fabio19 said:


> Better OPA 1611 or OPA 1622?


You should probably use something to match the original opamp, regarding the no. of inputs & outputs.

I guess that a dual opamp might measure and sound pretty much more identical on both channels (both channels are on the same silicon die), while two different opamps (especially if they're from different lots) might measure a little bit different (of course, the worst case scenario would be still below 0.01dB difference, so inaudible).

Maybe using two single opamps instead of a dual opamp might increase channel separation, but on today opamps the difference would be too small to measure it and definitely inaudible.

Again, stick with OPA1622 if the original opamp was dual and choose OPA1611 if the original opamp was single opamp.


----------



## Onik (Jan 15, 2021)

Complete 🍊 Mod done!

After installing the Orange Discrete opa in I/V Stage and leaving the 2 V6 classic I found everything got more accurate with details while using ATH-R70X, AKG K702 65TH, before I had 4 V6 classic and sound was warm but not in an exciting way.
Now I can feel the bass response with K702 65th and get the rumbling( which didn't happen before) when listening to rock/metal and even Jazz, I think need to burn the Orange opas few more days to truly enjoy the sound.

I think I'm gonna leave the V6 classic on LP/HPO stage for now because I think only I/V stage plays a big role to change the sg on playmate but I might be wrong, if I get bored ill then put vivids in LP stage.

*EDIT: I was wrong I rolled 2 Vivids in LP/HPO Stage on Playmate I feel like the soundstage now is even bigger than before Classical and Jazz music sounds really great with this setup and the bass is now more controlled while not losing any details, I think this will be my new playmate setup for now (I might try later all 4 orange opas).*

I don't know why I couldn't find a real review for these op amps, I think orange amp is not serious about marketing like burson they are too busy with their guitar amps, but I was curious to try their opa with or without reviews.


----------



## duranxv (Jan 14, 2021)

Since there's been much debate and feedback so far, what do you guys think of the Sparkos opamps?  Seems like they consistently outperform Burson and Sonic Imaging Labs based on what people are saying, but I could be wrong.  I currently use Fostex TH900's, so I'm looking for something that keeps the bass power, bump up the midrange a bit and tame the treble.


----------



## Sam Spade (Jan 14, 2021)

duranxv said:


> Since there's been much debate and feedback so far, what do you guys think of the Sparkos opamps?  Seems like they consistently outperform Burson and Sonic Imaging Labs based on what people are saying, but I could be wrong.  I currently use Fostex TH900's, so I'm looking for something that keeps the bass power, bump up the midrange a bit and tame the treble.


I have a pair of Dual Sparko Pro's I've tried in my conductor 3X ref. Fitting is the main issue, they are quite large. They also draw a lot more current. Burson is confident that won't be a problem. I asked if the conductor will cope with two dual op amps that draw 120mA in total and 4 that draw 240 mA in total. Burson said "_120ma is very high, it will not work in many applications but our Conductor is designed for opamp rolling so there is enough headroom for such current draw."_

On initial listen they sounded really great but only had them running with the lid off so far. Unfortunately my C3X has a problem (not related to the sparkos) so my listening comparisons were cut short and it might have to go back to Melbourne for repairs, but I'm only 800km away in Adelaide.

I'm confident I can fit 2 pros. It will require straight and bendy dip8 extensions. And possibly a tech with really good soldering skills but I have one of those. Once I've got the two pros sorted for the LP stage I'll consider the IV stage. That could stay as either bursons V6 options, Sparko DUAL DISCRETE OP AMP SS3602 or ideally if I can fit them 2 more Sparko PRO DISCRETE OP AMP SS2590.

The C3X ref is in my main system. I have a Sparko Aries in my home office driven by a Chord Qutest from a Marantz CD80 as transport and I need to hook up my PC and A&K SP1000M. The Aries uses the sparko pros exclusively and it is sublime with the Marantz transport, Chord Qutest and my Audeze LCD4s, like beyond good. It may be the best home audio solution I have ever heard and I used to sell top end hifi and have heard some amazing systems in store, at shows and in private homes. Even Sony MDR r10s. But that was about 1990.  

I wouldn't write off the Bursons though. They are awesome and the difference between the V6 options and the sparko SS3602 duals may be a matter of taste. But I haven't even finished comparing the V6 vivids and V6 classics yet. And I don't have any sparko SS3602 duals and haven't listened to them. I might get some shipped and see. Certainly it will be less buggering around trying to fit them in the IV stage compared to the Pros.

I think it is possible that the Sparko pro SS2590 is better than anything on the market. But that is in delivering a completely uncoloured reproduction, and that might not suit all tastes. The reason I went for them is why not try the best.

I absolutely love my C3X it is a great preamp, headamp and DAC. It may be that the Sparko Aries sounds even better as a headamp/preamp. But it has no remote. So while that is a non-issue on my home office desk it is a deal breaker for my main system which is stereo for music and AV. Dalisuite 3.5 towers driven by a Rotel RB1080, and the Conductor 3Xref and a Cambridge Audio 840c CD player and also a Cambridge Bluray player and a bunch of AV sources.


----------



## duranxv

Sam Spade said:


> I have a pair of Dual Sparko Pro's I've tried in my conductor 3X ref. Fitting is the main issue, they are quite large. They also draw a lot more current. Burson is confident that won't be a problem. I asked if the conductor will cope with two dual op amps that draw 120mA in total and 4 that draw 240 mA in total. Burson said "_120ma is very high, it will not work in many applications but our Conductor is designed for opamp rolling so there is enough headroom for such current draw."_
> 
> On initial listen they sounded really great but only had them running with the lid off so far. Unfortunately my C3X has a problem (not related to the sparkos) so my listening comparisons were cut short and it might have to go back to Melbourne for repairs, but I'm only 800km away in Adelaide.
> 
> ...



That's really helpful! Thanks! I'm more of a basshead myself, but I do appreciate clarity and detail too - would love to get your impressions on the Burson V6 vivids and the Sparkos 3602's when you get them!


----------



## Sam Spade

duranxv said:


> That's really helpful! Thanks! I'm more of a basshead myself, but I do appreciate clarity and detail too - would love to get your impressions on the Burson V6 vivids and the Sparkos 3602's when you get them!


The headphones i have, LCD4s LCD3s and even LCDxc have plenty of bass. I've done a fair bit of listening with the V6 vivids in the Conductor 3x ref as a headamp and preamp and the bass is great. But haven't done any proper comparisons yet. But i would have thought headphone choice was more important than opamps to get the right bass for you.


----------



## Themilkman46290

Sam Spade said:


> The headphones i have, LCD4s LCD3s and even LCDxc have plenty of bass. I've done a fair bit of listening with the V6 vivids in the Conductor 3x ref as a headamp and preamp and the bass is great. But haven't done any proper comparisons yet. But i would have thought headphone choice was more important than opamps to get the right bass for you.


Long time lurker, I would say you're right, opamps only barely help for that, headphones are definitely a better upgrade then op amps for bass, then source, then maybe opamps


----------



## saeid72 (Jan 25, 2021)

I got OPA2107
Bass: OPA2107 (Most impact Bass) > LM4562 (not the Strongest) > OPA2134 (More sub bass)  > NJM4556 (Natural) > NJM2068 (Lack of Bass)
Mid: OPA2107 (Texture and the most Low Mid) > LM4562 (Deep and Warm) > NJM4556 (Natural not Special) > NJM2068 (Thin and Flat) > OPA2134 (Very Forward and Lack of Deep)
Treble: OPA2107 (Warmest) = LM4562 (Balanced Warm and Texture) > OPA2134 ( Warm but Lack of air ) > NJM4556 (Natural) > NJM2068 (Bright)
Soundstage: OPA2107 (Wide and more Deeper) = LM4562 (Deep and more Wider) > NJM4556 (good Soundstage) = NJM2068 (good Soundstage) > OPA2134 (Narrow and Forward, Lack of air )
Winner = OPA2107. more Fantastic sound. LM4562 more Hi-Fi Natural
I think mixing X1 AD8620 or 8066 input and X2 OPA2107 buffer is the best sound in the world for (Objective 2 amp). AD8620 add 3D soundstage and OPA2107 add fuller and warm. without bright Analog devices. I feel the lack of a Wide 3D holographic sound stage


----------



## duranxv

saeid72 said:


> I got OPA2107
> Bass: OPA2107 (Most impact Bass) > LM4562 (not the Strongest) > OPA2134 (More sub bass)  > NJM4556 (Natural) > NJM2068 (Lack of Bass)
> Mid: OPA2107 (Texture and the most Low Mid) > LM4562 (Deep and Warm) > NJM4556 (Natural not Special) > NJM2068 (Thin and Flat) > OPA2134 (Very Forward and Lack of Deep)
> Treble: OPA2107 (Warmest) = LM4562 (Balanced Warm and Texture) > OPA2134 ( Warm but Lack of air ) > NJM4556 (Natural) > NJM2068 (Bright)
> ...



Interesting - I noticed though that the OPA2107's are a pretty old model.  I think they're like 10 years old at this point?  I gotta imagine there's been at least some improvements over that time, no?


----------



## saeid72 (Jan 15, 2021)

duranxv said:


> Interesting - I noticed though that the OPA2107's are a pretty old model.  I think they're like 10 years old at this point?  I gotta imagine there's been at least some improvements over that time, no?


it's true. Sound quality improvement is slow. opa2107(2003) and lm4562(2006) also old headphones sen hd650(2003) beyer dt990(1985). newer opa1642 (2009) and sennheiser hd660s(2017) not better or improvement, Just different


----------



## duranxv

Sam Spade said:


> The headphones i have, LCD4s LCD3s and even LCDxc have plenty of bass. I've done a fair bit of listening with the V6 vivids in the Conductor 3x ref as a headamp and preamp and the bass is great. But haven't done any proper comparisons yet. But i would have thought headphone choice was more important than opamps to get the right bass for you.



I have a pair of TH900's so bass isn't a problem, haha


----------



## Themilkman46290

duranxv said:


> I have a pair of TH900's so bass isn't a problem, haha


Maybe try the source, for a while I tried op amps for bass, realized it's not nearly as big of an improvement as headphone or a different source. 
Opamps don't really give big changes in bass, in other words, you won't get more dB of bass, what you might get is cleaner bass or better pronounced bass, I guess at the end of the day, for true bass heads, nothing beats a good eq

The nuances between amps are not night and day, except if you compare originals to fakes, then yeah, there is a bigger difference 

I have tried burson, muses, and a lot of others, but ended up with ad8620 in som things, ad823 in others, lm4562 is great in the bass region, lme49720ha was awesome in sub bass, opa2132 is great if you eq a lot, so is the Burson v5i 

But none of the pricier made a huge difference, some I couldn't tell apart, at one point I thought I was listening to the v5i and it turned out I had the ad823 in place
That's when I realized, if you want a good opamp, figure out what is good in your circuit


----------



## duranxv

Themilkman46290 said:


> Maybe try the source, for a while I tried op amps for bass, realized it's not nearly as big of an improvement as headphone or a different source.
> Opamps don't really give big changes in bass, in other words, you won't get more dB of bass, what you might get is cleaner bass or better pronounced bass, I guess at the end of the day, for true bass heads, nothing beats a good eq
> 
> The nuances between amps are not night and day, except if you compare originals to fakes, then yeah, there is a bigger difference
> ...



I ordered the Sparkos Op-Amps, so once I get those and get to test them out, I'll detail my impressions here!


----------



## Audio Addict

I just received my Sparkos Labs SS2590 order for my Apache.  They just barely fit with the side of the two outter SS2590s' PCB resting against the side of the case.  Out of the box these are so far above any other chips I have tried in the Apache which includes the SS3601s.  They are very musical with excellent quality and clarity in the bass.  The one thing I did not consider was the increase volume from them.  I had to turn the volume down 2 clicks.

We will see how they settle over the next couple of weeks.


----------



## ChevyMonsenhor (Jan 21, 2021)

Any chance i can get one of those DIP 8 extensions from China?
I tried searching for them on Aliexpress but i couldn't find any, for some reason.
I'm gonna try to fit a Burson V6 inside my xDuoo XD05.


----------



## Sam Spade

ChevyMonsenhor said:


> Any chance i can get one of those DIP 8 extensions from China?
> I tried searching for them on Aliexpress but i couldn't find any, for some reason.
> I'm gonna try to fit a Burson V6 inside my xDuoo XD05.


Burson has them on their website. Ive got some other links too.


----------



## Themilkman46290

ChevyMonsenhor said:


> Any chance i can get one of those DIP 8 extensions from China?
> I tried searching for them on Aliexpress but i couldn't find any, for some reason.
> I'm gonna try to fit a Burson V6 inside my xDuoo XD05.




Huo Guang store
Look for dip 8 extensions


----------



## ChevyMonsenhor

Themilkman46290 said:


> Huo Guang store
> Look for dip 8 extensions





Sam Spade said:


> Burson has them on their website. Ive got some other links too.



Thanks guys! I ordered one, hopefully i can shoehorn the V6 inside the XD05 case lol


----------



## duranxv

My Sparkos op-amps just arrived, so I'm going to plug them into my SoundBlaster AE-9 and will hopefully detail my impressions when I have time to test them in different applications.


----------



## Onik

Can anyone recommend me any good sounding IC/CAN Dual Op Amps with max +-18V operating voltage and with more than 100ma output current.


----------



## Sam Spade (Jan 23, 2021)

ChevyMonsenhor said:


> Thanks guys! I ordered one, hopefully i can shoehorn the V6 inside the XD05 case lol



For products that help replace OEM opamps I've found some options. 

Burson have 35 mm extension leads. If you are careful and bend them slowly you can bend them without breaking the wire. They have other stuff too. https://www.bursonaudio.com/product/35mm-extension-lead-x-2/ 

These are longer,  40mm? and look more flexible https://www.pornfreen.top/index.php?main_page=product_info&products_id=218375

This site is good and the short ones than come pre bent:
https://www.aliexpress.com/item/1005001345216954.html?spm=a2g0o.detail.1000014.1.1ecb48b85X3XFs&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.14976.197020.0&scm_id=1007.14976.197020.0&scm-url=1007.14976.197020.0&pvid=067666d7-6398-4268-8c27-ea20cc9e9309&_t=gps-idcDetailBottomMoreOtherSeller,scm-url:1007.14976.197020.0,pvid:067666d7-6398-4268-8c27-ea20cc9e9309,tpp_buckets:668#0#131923#0_668#888#3325#2_4976#0#197020#11_4976#2711#7538#278_4976#3104#9653#10_4976#4052#21623#67_4976#3141#9887#2_668#2846#8113#1998_668#2717#7564#650_668#1000022185#1000066059#0_668#3422#15392#933_4452#0#189847#0_4452#3474#15675#128_4452#4862#22449#76_4452#3098#9599#90_4452#3564#16062#402

Also this one comes recommended by Andrew Sparko. He said: "_Digikey is a place like mouser. They just sell electronic parts and they sell pretty much everything."_

Here's my work in progress:











Cheers
Sam


----------



## tmb821

ChevyMonsenhor said:


> Thanks guys! I ordered one, hopefully i can shoehorn the V6 inside the XD05 case lol


Please let us know if you figure out how! I have a V6 vivid dual that I would love to run in the xDuoo. Currently running the V5i in the xDuoo.


----------



## cqtek (Jan 25, 2021)

Hello everybody.
Do you know any reliable shop to buy LM4562, LME49860NA, OPA2107 or LME49720NA? If possible on AliExpress or another site that can ship to Spain.

Thank you very much.


----------



## Onik

cqtek said:


> AliExpress


LOL


----------



## ChevyMonsenhor

Onik said:


> LOL


Some of us have to rely on that, myself included


----------



## Onik (Jan 25, 2021)

Sam Spade said:


> For products that help replace OEM opamps I've found some options.
> 
> Burson have 35 mm extension leads. If you are careful and bend them slowly you can bend them without breaking the wire. They have other stuff too. https://www.bursonaudio.com/product/35mm-extension-lead-x-2/
> 
> ...


you could buy SS3601 for buffer and use more extra dip-8 extension for the pro op amps to make it taller , then you might not need the wire extension sockets which looks funny.


----------



## Onik

ChevyMonsenhor said:


> Some of us have to rely on that, myself included



I know but most op amps they sell are dodgy.


----------



## Audio Addict (Jan 25, 2021)

Onik said:


> you could buy SS3601 for buffer and use more extra dip-8 extension for the pro op amps to make it taller , then you might not need the wire extension sockets which looks funny.



I would be careful replacing a buffer chip like the 634 with an ordinary opamp like the the Sparkos Labs SS3601.  I have talked to Ray Samuels for my Apache as well as Andrew at Sparkos Labs and buffer chips like the OPA634 are different.  Neither recommended a replacement for the 634.  As such, I have not swapped those out.


----------



## cqtek (Jan 25, 2021)

Onik said:


> I know but most op amps they sell are dodgy.



That is why I am asking. In my country, a few years ago I was able to buy the LME49720NA and the LME49720HA from local online shops. Now I can only find the LME49720NA but for SMD mounting.
I wanted to open the ACMEE MF-01 to change the "Muses02" for the Burson V5i, but it doesn't fit. I've tried it with several sockets to see how it works. I also tried the LME49720NA and LM4562.
This DAP comes standard with the Muses02, I don't know if it's original. But I felt that its sound was a bit dark and soft. After switching to the LME49720NA its sound became more analytical and clear, as I like it. But I found the LM4562 a bit softer, even though many people here say they are the same... I found the V5i somewhat brilliant, but I didn't stay with it for long, so as not to get infatuated, because it doesn't fit.

I've been tempted to buy here, but I wanted to ask you guys for your experience.

https://hifivvaudio.es.aliexpress.com/store/group/Doble-OP-AMP/1799190_501911048.html?


----------



## Merlin-PT (Jan 26, 2021)

If anyone needs SOIC to DIP8 adapters with PCB cooling, for opamps with EP (Exposed Pad), like the  AD8397 (EP package) , I found/ordered this, but they didn't arrived yet, so I didn't tried them: https://www.aliexpress.com/item/32940175076.html


----------



## CoiL

cqtek said:


> Hello everybody.
> Do you know any reliable shop to buy LM4562, LME49860NA, OPA2107 or LME49720NA? If possible on AliExpress or another site that can ship to Spain.
> 
> Thank you very much.


Why not from mouser ESP? https://eu.mouser.com/ 
Why not farnell? https://es.farnell.com/
Why not TME? https://www.tme.eu/es/en/


----------



## Mad Max

Not his fault if he did not know, though now he will.


----------



## AudioCats

I haven't been keeping up with opamp reviews for a while.... what are the current best options for buffer and voltage-gain purpose? (in a stanard DIP8 or SOIC-8 package)

Is the opa627/637 still considered as the "top of the line"?


----------



## Sam Spade

duranxv said:


> That's really helpful! Thanks! I'm more of a basshead myself, but I do appreciate clarity and detail too - would love to get your impressions on the Burson V6 vivids and the Sparkos 3602's when you get them!



Actually some more thoughts. I sold Hi end hifi while I was at uni circa 1990. I'm a music lover not an audiophile but the gear and all that surrounds it intrigues me. 

What I chase is gear that 1) gives me the same emotional response as a live performance, and 2) is as accurate and detailed as possible. 

I think that speakers/headphone choice and amplification are the two most important aspects of bass performance. Then source. In my experience an amp with plenty of power and a high damping factor will grab a pair of speakers and give you the best bass extension and impact. I have a pair of Dalisuite 3.5 tower speakers rated about -3db at 30Hz. I have an excellent Marantz PM80 amp, 20 wpc class A switchable to 100 wpc class AB. It is a beautiful amp, and currently is running my dynaudio 2 way bookshelf speakers on my home office desk. Plus the headphone stage on it beats so many headphone amps out there. It was great with the Dali towers. But when I switched in a Musical Fidelity nuvista pre and a 200wpc Rotel RB1080 it transformed the speakers. I suddenly thought that I really was getting -3db at 30hz. The dynamic response changed, the transients, the dynamics were so much more like a live performance. 

But I would say that the source is probably most important for detail and musicality. But then you need the rest of the chain to carry that to your ears.


----------



## flibottf (Feb 2, 2022)

Little shot of the Burson v5i inside the XDuoo XD05 plus!

Burson v5i-s


----------



## leeperry

AudioCats said:


> I haven't been keeping up with opamp reviews for a while.... what are the current best options for buffer and voltage-gain purpose? (in a stanard DIP8 or SOIC-8 package)
> 
> Is the opa627/637 still considered as the "top of the line"?



OPA828 is their newest upgrade


----------



## duranxv

I've been using the Sparkos op-amps with my Sound Blaster AE-9, and they really rock.  My only concern is that the size of these op-amps make a very cramped fit.  I tried using some risers to put them on different levels, but even then it's a very delicate set up.  Even a small bump will knock any of those op-amps out of their sockets.

Anyone have recommendations of long flexible wires that can create more space between them by having them hang off rather than sit next to each other?


----------



## Sam Spade

duranxv said:


> I've been using the Sparkos op-amps with my Sound Blaster AE-9, and they really rock.  My only concern is that the size of these op-amps make a very cramped fit.  I tried using some risers to put them on different levels, but even then it's a very delicate set up.  Even a small bump will knock any of those op-amps out of their sockets.
> 
> Anyone have recommendations of long flexible wires that can create more space between them by having them hang off rather than sit next to each other?


Yes remind me with a pm if i dont get back to you in 24 hrs. Its all open on my home pc and im out. Trying to fit 2 ideally 4 spqrko pro op amps into a burson conductor 3X ref..


----------



## duranxv

Sam Spade said:


> Yes remind me with a pm if i dont get back to you in 24 hrs. Its all open on my home pc and im out. Trying to fit 2 ideally 4 spqrko pro op amps into a burson conductor 3X ref..



Any luck?


----------



## Setmagic

Hello, I want to create a opamp dip8 riser on 5cm wire. 
I have some 1,5mm high qiality 20awg ofc shielded cable for that and specially for audio tin-silver for soldering.
I want to create something like Burson dip8 riser but with longer protected wires.
It will work in proper way?


----------



## lafeuill (Mar 20, 2021)

Sparkos SS3602 on a Violectric V200

Very noticeable gain on clarity, and pretty much every other aspects of sound

Been waiting to try them for a very long while

Not disappointed  






D8000 Pro headphones, and LPG as source


----------



## Sam Spade

Setmagic said:


> Hello, I want to create a opamp dip8 riser on 5cm wire.
> I have some 1,5mm high qiality 20awg ofc shielded cable for that and specially for audio tin-silver for soldering.
> I want to create something like Burson dip8 riser but with longer protected wires.
> It will work in proper way?


These are 43mm and are flexible, you might be able to get something off the shelf : https://www.aliexpress.com/item/4001179833921.html?spm=a2g0o.cart.0.0.21933c000rBujb&mp=1


----------



## Sam Spade

duranxv said:


> Any luck?


Yep  opamp connectors galore:

45mm :https://www.aliexpress.com/item/4001179833921.html?spm=a2g0o.cart.0.0.21933c000rBujb&mp=1

30mm https://www.bursonaudio.com/product/35mm-extension-lead-x-2/

short and straight or bent  https://shoppingcart.aliexpress.com/shopcart/shopcartDetail.htm?spm=a2g0o.detail.0.0.1ecb48b85X3XFs

That was just a quick search


----------



## DJ LP

redrol said:


> I just got a Burson V6 Vivid and stuck it in my Xduoo 05+.  Initial impressions are VERY good.  I've got 6 TIs and the Muse 02 at the moment for testing.  V6 is FAR better than any of the TI's and it's not subtle.  It's bold and rippling with detail and power.  Instant love.  Will post a more in depth review.


Please do post your impressions. I have the XD-05 Plus as well. Just got it. I was looking at changing the op amp. The Muse 02 is one of my finalist based on what I read. The other 3 are the Burson V5i and the OPA 2227 and 2228. I only added them in case you have any experiences with them as well. I'm after a wide soundstage, very detailed, warm sounding, not analytical and edgy, with good dynamics and bass output. I'm new to this op amp thing, so any info you have would be a big help.


----------



## Setmagic

@DJ LP

I have a burson V5i and V6 Classic, and tested with 2228, 1612, 8820, 1361, 1364, 8620, 275 and 49720.
For price/performance 2228 is best opamp and you can buy. You can use a little better 228 as 2x single configuration for xd05+
V5i will be notable superior. Quite similar in sound signature to 2228 but definitely higher level. You can go for V5i dual for better fit.
V6 Classic (don't heard vivid) is only a little better than V5i. 40% more power consumption and can't fit without heavy modifications, no protection from RFI as V5i.
V6 is made for hi-grade desktop audio equipment as upgrade stock IC and there can really do the job.


----------



## DJ LP

Setmagic said:


> @DJ LP
> 
> I have a burson V5i and V6 Classic, and tested with 2228, 1612, 8820, 1361, 1364, 8620, 275 and 49720.
> For price/performance 2228 is best opamp and you can buy. You can use a little better 228 as 2x single configuration for xd05+
> ...


Thank you so much for your help with this. Ok, so the Burson V5i Dual will give me the sound signature I'm looking for. Should I look out for fakes? Are there certain websites I should go to?


----------



## Sam Spade

DJ LP said:


> Thank you so much for your help with this. Ok, so the Burson V5i Dual will give me the sound signature I'm looking for. Should I look out for fakes? Are there certain websites I should go to?


Go direct to burson. They are great.


----------



## Themilkman46290

DJ LP said:


> Thank you so much for your help with this. Ok, so the Burson V5i Dual will give me the sound signature I'm looking for. Should I look out for fakes? Are there certain websites I should go to?


I agree with Sam spade, Burson has great service and reliable shipping, I was surprised because normally shipping is not easy to my country but it got here in about 10 days. 
Fastest non express shipping I ever had


----------



## Sam Spade

Themilkman46290 said:


> I agree with Sam spade, Burson has great service and reliable shipping, I was surprised because normally shipping is not easy to my country but it got here in about 10 days.
> Fastest non express shipping I ever had


Ive bought op amps and low jitter digital clock from them about 10 years ago to mod my marantz CD80 plus new caps and a Philips TDA1541A S2 double crown d/a converter. I've bought a conductor 3x ref and audeze LCD3 package from them. And a pair of V6 classic dual op amps. Alex and dennis are excellent, great service honest advice and opinions. And their equipment is sensational quality and value. And i love the way they structure their range it's strong at every price point. Someting for everyone great quality, performance AND value. When i wanted to try the Sparko Pro op amps in my conductor i asked their opinion because a pair of sparko pros draw i reckon it's at least 5 times the current than the burson V6s. They were great and happy to advise. Burson are like these bunch of maniacs obsessed with pushing the envelope making better products at a great price. They seem to be in it for love not profit. Mind you i have 4 pairs of Audeze at the moment and Chris at Audeze is a dead set legend too another great company with great products. I have a Sparko Aries fed by a Chord Qutest in my home office and Andrew Sparko is just great too and his partner Alisa i think her name is. 

There are some really good audio companies out there. I love my Chord and Astell & Kern gear too, as well as marantz, musical fidelity, Rotel and Dali but I've never dealt with those companies directly.


----------



## DJ LP

Sam Spade said:


> Go direct to burson. They are great.


It is the dual and not the single, correct? I'm ordering once you tell me which one.


----------



## DJ LP

DJ LP said:


> It is the dual and not the single, correct? I'm ordering once you tell me which one.


Never mind. Your already posted dual.


----------



## Sam Spade

DJ LP said:


> It is the dual and not the single, correct? I'm ordering once you tell me which one.


I can't advise on dual or single it depends on the unit id ask the manufacturer and ask burson as well.


----------



## Widea

Did anyone ever try a NJM4580? It is old but compared to several opamps I find it very nice to listen to. Especially set to class-A.


----------



## beanxinh

My sparkos with xd05 plus. The Sparkos make the sound a little bit snappier than stock op amp. 
I also tried OPA627AU which make the sound too soft for my tastes.


----------



## DJ LP

beanxinh said:


> My sparkos with xd05 plus. The Sparkos make the sound a little bit snappier than stock op amp.
> I also tried OPA627AU which make the sound too soft for my tastes.


How did you get the screws off? I can't get mine off. I went and purchased 2 screwdriver kits, 1 being a 60 piece. I thought it was a T6 torx but that didn't work.


----------



## beanxinh

DJ LP said:


> How did you get the screws off? I can't get mine off. I went and purchased 2 screwdriver kits, 1 being a 60 piece. I thought it was a T6 torx but that didn't work.


It used a normal hex screw. You can buy an Allen key set in metrics system and it good to go. I'm not sure if it is 2mm or 1.5mm.


----------



## LaughMoreDaily

Anyone know the perfect opamp(s) for the JAZZ R7.0/R7.8 Amps?


----------



## Setmagic

@LaughMoreDaily Burson V5i if will fit


----------



## LaughMoreDaily

Setmagic said:


> @LaughMoreDaily Burson V5i if will fit


I think it might... I have a large opamp in there right now and it touches the top of the case when closed.

Is Burson the only one you like in this amp?


----------



## Setmagic (Apr 5, 2021)

@LaughMoreDaily all OpAmp have some flavores and quality.
Rich sound: OP2228
Warm: Muses series especially 02/8820 (best is 03 but it's expensive and mono so need 2 of them with some mods with JAZZ)
Well balanced LM49720
Bass heavy: LT1364
Best overall: Burson V5i
Best possible: Burson V6 Classic
Last one need some heavy mods for implementation


----------



## povidlo

Please check out my review of Walnut F2.

Includes notes on stock OPA2604, NE5532, V5i, and V6 Classic opamps.

https://www.head-fi.org/showcase/walnut-f2.24964/reviews


----------



## bust3r

Hey all, maybe I can get some opinions?  I have a EVGA Nu Audio PC sound card if anyone is familiar with it.  Presently it has the stock ADI OP275 (headphone) and ADI AD8056 (Line out) OP AMPS and I'm going to be switching them out for two OPA1612 OP AMPS, for headphone and line out.

Good idea or no?  

I'm under the impression I replace the headphone and line out with the same model OP AMP.  I really can't find much about the AD8056, but a ton about the OPA1612's.  I've heard it's a very good amp and bought them based on the mainly positive reviews.  Thanks!


----------



## FritzS (May 24, 2021)

Setmagic said:


> @DJ LP
> 
> I have a burson V5i and V6 Classic, and tested with 2228, 1612, 8820, 1361, 1364, 8620, 275 and 49720.
> For price/performance 2228 is best opamp and you can buy. You can use a little better 228 as 2x single configuration for xd05+
> ...



In older HA project (made early 2009) I used some OPAs such as LM6171, AD843, OPA602, AD847, LT1056, LT1022, TLE2071, OPA604, LME49710, OPA627, Supreme Sound Opamp V5S, AD797, OPA134.
Last time I tested AD797 and OPA134, surprisingly, these sound very good, a touch more appealing than all the others before.
Some German manufacturers of headphone amplifiers use OPA134/OPA2134, Jan Meier sometimes AD797, Funk probably LME49710 series or its dual types.

Supreme Sound Opamp V5S I also like very much but not optimal.

As attachment the unmodified schematics of amplifier and rail splitter. I have improved some things there.

The project thread: https://www.head-fi.org/threads/new-wna-mkll-head-amp-kit.99596/


----------



## Magic77

Just a quick question for the opamp rollers. Could a Bipolar chip be used in a circuit that originally uses a JFET chip? Thanks


----------



## FritzS

@Magic77
There is no clear 'yes' and no 'no' to this.
It depends entirely on the circuit design all around and on the respective OPA.
In my circuit, the NFB resistors have low impedance, so I can easily switch between BJT and FET types.
In my circuit, you should only use OPA types that run without problems from a gain factor of 1.


----------



## Magic77

FritzS said:


> @Magic77
> There is no clear 'yes' and no 'no' to this.
> It depends entirely on the circuit design all around and on the respective OPA.
> In my circuit, the NFB resistors have low impedance, so I can easily switch between BJT and FET types.
> In my circuit, you should only use OPA types that run without problems from a gain factor of 1.


Thank You for your response. I figured also that it’s important to know the type of circuit first. I know plenty of people just do swap outs and are not really sure if they are truly correct. Just curious if you have tried any of the discrete opamps that are available such as the ones from Burson Audio. 


FritzS said:


> @Magic77
> There is no clear 'yes' and no 'no' to this.
> It depends entirely on the circuit design all around and on the respective OPA.
> In my circuit, the NFB resistors have low impedance, so I can easily switch between BJT and FET types.
> In my circuit, you should only use OPA types that run without problems from a gain factor of 1.


----------



## povidlo

Made a simple, non-technical review of Little Bear portable tube amp using Burson Audio Supreme Sound V6 Vivid opamps. 

Chech it out: https://www.head-fi.org/showcase/little-bear-b4-x.25234/reviews


----------



## Setmagic

I have question about OPA1622 implementation.
In official Texas Instruments evaluation board they suggest 10uF in rail capacitors

I have spare 47, 100 and 220uF good electrolytic capacitors.
In many DIY applications I see 100 or 220uF capacitors in such headphone output.
I figured out my device have originally 10uF MLCC as well probably due to space and price performance.
Do You think putting additional 100 or 220 uF can improve sound quality?


----------



## raoultrifan

It's all about lowering the ripple without inducing pre/post ringing on the V+/V- rails. Use a scope and record power ON and power OFF then see if there's any ringing. Also, check if the ripple & noise across V+/V- is below 1 mV RMS. If so, then forget about adding more (or bigger) caps.

Worrh mentioning that sound quality is measurable, so give it a try. Although given today opamps' PSRR, PSU's ripple will not affect opamp's outter THD+N, unless PSU is defective or not properly choose for this application.


----------



## Setmagic

Thank You @raoultrifan, it's time to go for scope.


----------



## redrol

cqtek said:


> That is why I am asking. In my country, a few years ago I was able to buy the LME49720NA and the LME49720HA from local online shops. Now I can only find the LME49720NA but for SMD mounting.
> I wanted to open the ACMEE MF-01 to change the "Muses02" for the Burson V5i, but it doesn't fit. I've tried it with several sockets to see how it works. I also tried the LME49720NA and LM4562.
> This DAP comes standard with the Muses02, I don't know if it's original. But I felt that its sound was a bit dark and soft. After switching to the LME49720NA its sound became more analytical and clear, as I like it. But I found the LM4562 a bit softer, even though many people here say they are the same... I found the V5i somewhat brilliant, but I didn't stay with it for long, so as not to get infatuated, because it doesn't fit.
> 
> ...


What you talking about?


----------



## cqtek

redrol said:


> What you talking about?


There are different versions of this DAP, I have the first one whose power connector is not USB Type-C. I'm sure it's different inside too, because it doesn't really fit in my MF-01.


----------



## redrol

OH wow, ok.  Yeah mine is USB C


----------



## LaughMoreDaily

Are opamps dead now because of phone dongles?


----------



## motorwayne

LaughMoreDaily said:


> Are opamps dead now because of phone dongles?


----------



## Barusu Lamperouge

LaughMoreDaily said:


> Are opamps dead now because of phone dongles?


Probably. Also, the shift in habbits of folks streaming music as opposed to purchasing CDs and vinyls making on the go music listening preferable over leisurely desktop listening


----------



## Setmagic

Barusu Lamperouge said:


> Probably. Also, the shift in habbits of folks streaming music as opposed to purchasing CDs and vinyls making on the go music listening preferable over leisurely desktop listening


And audiophiles goes for discrete solutions in desktop equipment.
R2R DACs, fully transistor or tube amplifiers.


----------



## Barusu Lamperouge

Setmagic said:


> And audiophiles goes for discrete solutions in desktop equipment.
> R2R DACs, fully transistor or tube amplifiers.


But a significant segment of new "audiophiles" are gravitating towards this minimal setup. I'm not saying that the market is dead but it is not as buzzing as it used to be.


----------



## Plancu

Hi everyone!

I'm the proud owner of an aging but still amazing Auzentech X-Fi Forte that's further connected to a NAD C315BEE and a pair of Paradigm Atoms.

I did some recent research into Zishan Z1 and Z3. Their dedicated threads are full of people "complaining" that an OPAMP update causes a drastic improvement in sound.
X-Fi Forte has a DIP-8 socket and the stock LME 49720NA.

Is there any cheap priced (~10E) opamp that could noticeably improve the sound of X-Fi Forte?
I like a sound that's dynamic, fast, detailed and forgiving with poor recordings. I'm not very keen on soundstage.

I'd like to try to get the best of my sound card but the main goal here would be to not burn it. Is there the risk that an incompatible opamp can do that ? What should I pay attention to ?

I'm looking at OPA 2132 or Muses 8920 as replacements. Would the sound improvements be worth the effort & risk ?

Thank you in advance


----------



## Setmagic

Plancu said:


> Hi everyone!
> 
> I'm the proud owner of an aging but still amazing Auzentech X-Fi Forte that's further connected to a NAD C315BEE and a pair of Paradigm Atoms.
> 
> ...


This is greate sound card and yes sound will change.
You can try OPA1622, AD8620 or Burson V5i or just go for something really expensive like Burson V6 classic


----------



## Plancu

Setmagic said:


> This is greate sound card and yes sound will change.
> You can try OPA1622, AD8620 or Burson V5i or just go for something really expensive like Burson V6 classic



Thank you for the suggestions. Any links where I can get the hopefully non-fake versions ? Or at least photos on how they should look like ?


----------



## Setmagic (Aug 20, 2021)

Plancu said:


> Thank you for the suggestions. Any links where I can get the hopefully non-fake versions ? Or at least photos on how they should look like ?


100% original will be in official distributors of Burson for this OpAmps. Other in www.mouser.com www.digikey.com for example.

Difference in sound between fake and original is so huge that is dosent worth to risk.
Sometimes fake is as good looking as ori and sounds just ok because it's a "rebranded" cheapest generic opamp for few cents.

I have original lme49720 and fake one from AliExpress. And they sound like night and day.


----------



## Plancu

Setmagic said:


> 100% original will be in official distributors of Burson for this OpAmps. Other in www.mouser.com www.digikey.com for example.
> 
> Difference in sound between fake and original is so huge that is dosent worth to risk.
> Sometimes fake is as good looking as ori and sounds just ok because it's a "rebranded" cheapest generic opamp for few cents.
> ...



Thank you


----------



## Setmagic

Plancu said:


> Thank you


You welcome. And remember always check if it's official distributor.

In these week I ordered OPA2134 from local "eBay" true legal store and was fake and sounds horrible.
I was reported seller and they refund money. They probably know it because have supplier from China.

I was lucky with AliExpress too and buy original opa1622 and opa1612.


----------



## Plancu

Setmagic said:


> I was lucky with AliExpress too and buy original opa1622 and opa1612.



What's the seller name ? I can only find some partial matches on www.mouser.com / www.digikey.com and everything is surface mount. That's way beyond my soldering skills.


----------



## Setmagic

Plancu said:


> What's the seller name ? I can only find some partial matches on www.mouser.com / www.digikey.com and everything is surface mount. That's way beyond my soldering skills.


Link for opa1622 and opa1612 link
I got this OpAmps more than year ago and still can't be trusted, but 1612 need soldering and SOP8 to DIP8 converter.
Don't go for 1612 it's a more chance to get fake.
Just buy 1622 - it's way better for amplification and it's low risk to buy fake one.
You can go for something fancy on a budget as well discrete opamp
Choose dual option.


----------



## Plancu

Setmagic said:


> Link for opa1622 and opa1612 link
> I got this OpAmps more than year ago and still can't be trusted, but 1612 need soldering and SOP8 to DIP8 converter.
> Don't go for 1612 it's a more chance to get fake.
> Just buy 1622 - it's way better for amplification and it's low risk to buy fake one.
> ...



Many thanks. I'll give them a try


----------



## sp33ls

I'm considering the OPA828 for my Whammy build (+/-15V discrete reg).

I'm curious if anyone thinks there's a risk for oscillation in the Whammy? Also looks like TI recommends a decoupling cap on the supply pins. I wonder if a 0.1uF cap across V+/V- would be sufficient..? Or does it have to be V+/GND & V-/GND?


----------



## collin1103

Hey guys, I have a couple questions to ask about opamps of course. I currently have a topping d10s, and I’m looking into changing out the opamp for something a little higher quality. I was really looking at the opa1656 but it seems like it’s going to take a month and a half to get here, all the soldered adapter ones on eBay, which i don’t know if I want to wait. Is there a better drop in solution or something around 15$ that is available in the USA? The one other thing is I’m going to be pairing it with a muse02 which is going to be in my little dot1+ when that gets here. Does this matter? Thanks


----------



## Setmagic

collin1103 said:


> Hey guys, I have a couple questions to ask about opamps of course. I currently have a topping d10s, and I’m looking into changing out the opamp for something a little higher quality. I was really looking at the opa1656 but it seems like it’s going to take a month and a half to get here, all the soldered adapter ones on eBay, which i don’t know if I want to wait. Is there a better drop in solution or something around 15$ that is available in the USA? The one other thing is I’m going to be pairing it with a muse02 which is going to be in my little dot1+ when that gets here. Does this matter? Thanks


Opa1656 is easy to got fake from china or just random seller.
You can start going for original Muse 8820 of You are tight on a budget. They are 90% of 02 ones.


----------



## collin1103 (Aug 26, 2021)

Setmagic said:


> Opa1656 is easy to got fake from china or just random seller.
> You can start going for original Muse 8820 of You are tight on a budget. They are 90% of 02 ones.


Thanks a lot. But yeah I’m not looking to spend a ton on this. I was thinking of even buying the opamp and the dip8 adapter off of digikey but I don’t think I’ll be able to solder something that small tbh. But  my amp is going to get the better stuff and I just want to upgrade a little bit for the dac so the 8820 should be perfect than for that. Thanks!


----------



## Setmagic

collin1103 said:


> Thanks a lot. But yeah I’m not looking to spend a ton on this. I was thinking of even buying the opamp and the dip8 adapter off of digikey but I don’t think I’ll be able to solder something that small tbh. But  my amp is going to get the better stuff and I just want to upgrade a little bit for the dac so the 8820 should be perfect than for that. Thanks!


I just watched specification of D10S there is 2134 so Muses 8920D will be better


----------



## Plancu

hi

Could anyone recommand ebay/AE shops selling original Muses opamps ? I checked www.mouser.com and www.digikey.com but they have expensive shipping (20 to 30$)

Thank you


----------



## Setmagic (Sep 5, 2021)

Plancu said:


> hi
> 
> Could anyone recommand ebay/AE shops selling original Muses opamps ? I checked www.mouser.com and www.digikey.com but they have expensive shipping (20 to 30$)
> 
> Thank you


Search of local bigger electronic commercial network shop. They have originals as well.


----------



## Plancu

Setmagic said:


> Search of local bigger electronic commercial network shop. They have originals as well.



Thank you for your suggestion.
Unfortunately the only larger online local retailer that I'm aware of does not stock it. 
The closest Brick and mortar is small and 2h away and I'd better take my chances ordering from china (this appeases the tiny gambling man inside me).


----------



## thale (Oct 3, 2021)

Plancu said:


> Thank you for your suggestion.
> Unfortunately the only larger online local retailer that I'm aware of does not stock it.
> The closest Brick and mortar is small and 2h away and I'd better take my chances ordering from china (this appeases the tiny gambling man inside me).


Shipping to EU is free from $50 at Mouser.
You have NO chance to get a real Muses opamp from China on ebay/ali.

On my D10s I've replaced the I/V opamps by 2 OPA1612 and the buffer by a Muses02.
And the result is beyond my expectations, it clearly worth the price of those 3 opamps.


----------



## Audio Addict

Has anyone tried this yet?  I can't find the height so they may be too tall for my use.

https://staccatoaudio.com/


----------



## sebek

Where can I confidently buy an original AD827SQ? I live in Europe.


----------



## thale

Mouser, Digikey, Farnell, or TME, they are located in Poland and the shipping cost is cheaper to EU.
Avoid e ebay / ali


----------



## PetFju

Hi guys. I am sort of a noob in this community (head-fi), been more of a traditional hifi nerd for many years. However, with young kids and a shared livingroom, hifi had to go for the time being. 
Anyways, i have gotten a Lillte Dot 1+ in which i changed the stock op amp with a Burson V6 vivid. This has been a revelation as far as op-amps go. I also purhased a V6 classic, which i like as well. 
Now i upgraded to a Xduoo TA-20 amp, on which i want to look at op-amp options. Has anyone had any experience with this amp and op-amp rolling? Or does anyone know anything about this amp and its op-amps? 
I did search this thread and online in general, but couldn't find anything. Any information would be greatly appreciated 

-Pete


----------



## hmscott (Dec 20, 2021)

PetFju said:


> Hi guys. I am sort of a noob in this community (head-fi), been more of a traditional hifi nerd for many years. However, with young kids and a shared livingroom, hifi had to go for the time being.
> Anyways, i have gotten a Lillte Dot 1+ in which i changed the stock op amp with a Burson V6 vivid. This has been a revelation as far as op-amps go. I also purhased a V6 classic, which i like as well.
> Now i upgraded to a Xduoo TA-20 amp, on which i want to look at op-amp options. Has anyone had any experience with this amp and op-amp rolling? Or does anyone know anything about this amp and its op-amps?
> I did search this thread and online in general, but couldn't find anything. Any information would be greatly appreciated
> ...


Hi, congratulations on the new TA-20, I have really enjoyed mine, here is where we discuss Xduoo amps on head-fi if you haven't found it yet:
https://www.head-fi.org/threads/xduoo-amplifiers.682282/page-53

Xduoo told me that no opamp is used for the XLR Balanced input.  The XLR input has a direct connection to the 12AU7's, directly driving the Discrete Transistor amplifier XLR output to the headphones. There is no need to consider swapping opamps for the TA-20 if you are only using the XLR Balanced input.

For this use Xduoo said "OPA's used on the RCA circuit is OPA2604, it is better than OPA2134."

The opamps are only used to convert the RCA Single-Ended inputs into a Balanced signal output to the Discrete Transistor amplifier.


Spoiler: Xduoo's responses to my questions about swapping opamps in the Xduoo TA-20:



Hi, Scott
1. U1, U2 is the OPA which convert the single-ended signal from RCA into a balanced signal. If it is a balanced input, the signal does not pass through U1 and U2.




The circuit architecture diagram is as follows



2. this is the DC TO DC power chip：



3. these are power chips:



*Best Regards, XXXXXX

2nd reply:*
Hi, Scott
...
OPA's used on the RCA circuit is OPA2604, it is better than OPA2134.
...
*Best Regards, XXXXXX*


I use all of the Xduoo TA-20 inputs, the XLR input is the Topping D90 MQA, RCA1(AUX1) input is my Nintendo Switch, and RCA2(AUX2) is a 6' 3.5mm to RCA cable I use to connect other devices audio/line outputs.

Maybe you could try an RCA to XLR cable to connect your RCA source(s) to the TA-20, rather than going through the trouble of trying to find a better OPAMP to swap on the TA-20?

The most improvement I've seen is with Tube Rolling - right now I'm favoring Mullard/Brimar ECC81/12AT7/6060 tubes - a big improvement from the stock tubes, and others I've also tried.

For noise reduction in my EMI/RFI environment getting the Mogami 2534 / 2893 wire-built cables from WBC also made a nice improvement by lowering the noise floor.

If you do go the opamp swapping route, I'd suggest running your ideas by support@xduoo.net to give Xduoo a chance to comment on your changes, before or after you try them 

@PetFju - Here are the cables I've used with the TA-20, and some of the current tubes - still available online:


Spoiler: Click to see links to the cables used...



Buy two, they sell as per cable, not pair - 1 Foot – Quad Balanced Microphone Cable Custom Made by WORLDS BEST CABLES – Using Mogami 2534 4-Wire Twisted and Neutrik NC3MXX-B Male & NC3FXX-B Female XLR Plugs.
https://www.amazon.com/gp/product/B00WU1BP10

(Pair) 1 Foot – Directional Quad High-Definition Audio Interconnect Cable Pair Custom Made by WORLDS BEST CABLES – Using Mogami 2534 4-Wire Twisted and Amphenol ACPR Die-Cast, Gold Plated RCA Connectors
https://www.amazon.com/gp/product/B01ALHTVMO

Less expensive BOM and build cost are WBC cables made with Mogami 2459 which is a 2 wire version, which is said to sound better if you don't need the EMI/RFI noise reduction of the 2534 / 2893 QuadStar 4 wire designs:

Buy two, they sell as per cable, not pair - 1 Foot - Balanced Microphone Cable Custom Made by WORLDS BEST CABLES - Using Mogami 2549 (Black) 2-Wire and Neutrik NC3MXX-B & NC3FXX-B Gold XLR Plugs
https://www.amazon.com/Foot-Balanced-Microphone-NC3MXX-B-NC3FXX-B/dp/B08Z7GGWYG

(Pair) 1 Foot – Directional High-Definition Audio Interconnect Cable Pair Custom Made by WORLDS BEST CABLES – Using Mogami 2549 2-Wire and Amphenol ACPR Die-Cast, Gold Plated RCA Connectors
https://www.amazon.com/gp/product/B01ALFR02Y

Check out this post for recent tube recommendations - and I have other posts in that thread with other tubes I have tried:
https://www.head-fi.org/threads/xduoo-amplifiers.682282/post-16699553


----------



## sp33ls

You likely won't see as much improvement with swapping out an OPA2604 for SE to Balanced duties.

Looks like you'd also need to re-solder in this case. I'd personally leave it alone in this particular amp/position.


----------



## PetFju (Dec 7, 2021)

Thank you so much for the info. I did try to find info about this in the Xduoo thread as well, but i guess i didn't look well enough 
Anyways, i do use the balanced inputs from my ADI-2 dac. So i guess there's no need to change anything. And i do have a pair of mullards on the way here, as well as some other tubes, can't even remember which ones atm. Sorry for hijacking this thread, i'll continue about this in the xduoo thread 

-Pete


----------



## hmscott (Dec 7, 2021)

Continuing here:
https://www.head-fi.org/threads/xduoo-amplifiers.682282/post-16699624


----------



## CopperFox

Hey all, I'm looking for an opamp that can be used in place of OPA2156 but has higher slew rate than it (which is 40V/us). Any suggestions?


----------



## Beefy (Dec 23, 2021)

CopperFox said:


> Hey all, I'm looking for an opamp that can be used in place of OPA2156 but has higher slew rate than it (which is 40V/us). Any suggestions?



Dare I ask why you need such a high slew rate?

The reason I ask, frequency capabilities relate to slew rate through the formula: Slew rate needed = 2 x Pi x frequency x voltage swing

Max safe voltage swing for an OPA2156 is probably 35V. At a slew rate of 40V/µs, you can reproduce music at full output up to 181 kHz.


----------



## sp33ls

And here I am using dual OPA828 for I/V duty lol


----------



## AJCxZ0

My <US$40 Fosi Audio P1 tube preamp/buffer with bass, treble and volume dials has two TI NE5532Ps. While my tube research has indicated some good choices for tube rolling, my opamp research has led me here seeking advice, even after having read many posts in this thread.
Having eliminated the discrete opamp options and ICs such as the MUSE01 on cost, but prepared to pay ~US$20 for e.g. a pair of MUSES8920Ds from Digi-Key, I'm looking to try to eliminate any limitations of the signal through the device resulting from the NE5532P such that all (or as close as possible) the "flavour" comes from the tubes. I'm not interested in replacing any soldered components (yet).

Examples of the form of advice I'd find most useful are: "NE5532P is the best suited at that budget", "MUSES8920D will eliminate the severe dynamic range compression of the NE5532P", or "the OPA2134PA is as good as the MUSES8920D at 2/3 the cost and doesn't have the 1.6 kHz peak and 10 dB roll-off at 80 Hz of the NE5532P which makes all music sound like a car horn". If that's not too much to ask, then I'd also like precise and correct names, ideally with links to manufacturer or vendor product pages, because while you know how the "OPA" compares to the "34" and that one is better in the post-raphaelite stage, I don't (yet), and I need to be able to buy a thing, plug it into one or both of the 8-DIP sockets and have it work.

Other advice about or observations of the Fosi Audio P1 are welcome.

The device is between a Topping E30 and L30, so I have plenty of clean, low noise, linear, etc. signal.






More photos in the album.

PS. I know I'm not asking the right question, so if what I've asked is insufficient for a useful answer, then please let me know how I can improve it. I also know that results can vary.


----------



## Voxata

Hey all! I've a question for the more technical folks. LME49724, am I able to swap this for OPA1656 without any issue?


----------



## AJCxZ0

AJZ0 said:


> My <US$40 Fosi Audio P1 tube preamp/buffer with bass, treble and volume dials has two TI NE5532Ps.
> The device is between a Topping E30 and L30, so I have plenty of clean, low noise, linear, etc. signal.
> More photos in the album.


Two dual Burson V6 Vivid fully discrete opamps arrived from Hong Kong courtesy of a generous offer from @John Burson at Burson Audio who asked only for "honest feedback and pictures of the upgrade posted in your frequent forums".

Since I am just starting my planned testing, I plan to split my review across multiple posts here, but first a photo of the V6 Vivids showing their neat packaging and how they might be a challenge to fit in the P1.





Caveats​To properly review an opamp swap usually involves making the swap in an amplifier where the difference can be directly experienced, whereas I am swapping opamps in not only a pre-amp, but a tube pre-amp with stock tubes in which the two opamps operate across tone controls and volume in a way which I don't understand. Testing will involve twiddling bass, treble and volume dials on the pre-amp in order to try to discern the difference between the TI NE5532Ps and the Burson V6 Vivid. To make this harder, I am unable to effectively A/B test, so will rely on memory of impressions, approximate volume matching and comparable twiddling.

The Plan​My test plan has three stages:

The Truth
Create a demo playlist
Choose review components excluding the pre-amp
Listen to the playlist

The Tubeth
Connect the Fosi Audio P1 between the DAC and amp
Listen to the playlist

The Vivid
Replace the two TI NE5532Ps with the Burson V6 Vivids
Listen to the playlist

The Playlist​A mix of aw-dee-oh-file demorific and familiar tunes to enable a suitable test of the highs, lows, wides, deeps and details with a mix of natural and synthetic sounds. Most files are 96 or 48 kHz 24 bit or 44.1 kHz 16 bit FLAC with a couple of 48 kHz Opus/Ogg. The fist uncontroversial choice.


Yosi Horikawa - Spaces - Timbres
Hans Zimmer - Dune Original Motion Picture Soundtrack - Dream of Arrakis
Pink Floyd - The Dark Side of the Moon - Time
How to Destroy Angels - Welcome Oblivion - Ice Age
NIN - Hesitation Marks "Audiophile Mastered Version" - Came Back Haunted
Daft Punk - TRON Legacy (The Complete Edition) - Solar Sailer
GUNSHIP - Dark All Day - Black Blood Red Kiss (feat. Kat Von D)
Public Service Broadcasting - The War Room - Spitfire
Steven Wilson - THE FUTURE BITES - KING GHOST
King Crimson - Radical Action to Unseat the Hold of Monkey Mind - Starless
Dire Straits - Brothers in Arms - Brothers in Arms
The Gear​Files on the PC played with Audacious go to EasyEffects where a full parametric EQ for Crinacle's Harman over-ear 2018 is applied with no further modification resulting in a 96 kHz PCM signal from PipeWire going to the Topping E30, which sends line level output to the L30 which powers my unmodified Sivga SV021. The intention here is accurate reproduction with a familiar sound signature in which the most components are neutral, i.e. do not significantly limit or colour the sound, leaving the colouring for the pre-amp stage. The second uncontroversial choice.
While an objective description of my hearing is impractical, mine has no noticeable damage and tops out somewhere around 14.5 kHz.

Impressions​The Truth​Neutral is far from boring. With the naturally bassy-V SV021 EQ'ed to the gently warm curve, all the available details of the tracks appear in their intended places. Low, high, loud and quiet and everything in between appear without great emphasis or evidence of distortion or limitation.
Since this is the reference listen, volume on the L30 stayed at a comfortably loud one o'clock for two playthroughs.


----------



## AJCxZ0

AJZ0 said:


> The Tubeth
> 
> Connect the Fosi Audio P1 between the DAC and amp


Before connecting the TUBE-P1 I thought I would practice removing the IC opamps and installing the V6s. I'm glad to I did, as unfortunately while one of them could be squeezed into one socket, the second is blocked by a capacitor.

Before removing the IC opamps it was clear that the V6 would be too tall to fit inside the case. This was not a surprise, however I hoped that wire pin connectors might allow them to be installed horizontally, but in any case [pun intended] I was going to test them with the case open.



Removing the IC opamps with large tweezers was easy.



The first V6 was a very tight squeeze between the capacitors, but alas the second was firmly blocked by a capacitor.






and the riser included in the case was insufficient to clear it (and the two risers don't stack).
While pin wires (which I don't have) could enable the V6 to be connected and lie vertically, there is insufficient clearance in the front of the case.






There are a few more photos from this effort in the album.

PS. Re-inserting the IC op-amps was not so easy as the pins did not align. I had to insert one side, then use the tweezers to gently push each  pin on the other side into the holes before pressing down to fully insert it.


----------



## John Massaria

I whole heartedly can recommend the sparkos  ss2590 which I use 4 in my ray samuels Apache - I’ve tried a ton of op amps - I wrote a review on it


----------



## sebek

If anyone in Europe is interested I am selling a Burson V5i-D and AD827SQ, both 100% original, used for no more than 5-6 hours honestly.


----------



## wein07

Does anyone know if the JRC MUSE01 is basically 2 pieces of MUSE03?


----------



## zachgraz

Hi folks, 
maybe you can help me with an upgarde to my OPA627 in an Ayon Skylla 2 DAC. The DAC is now 10 years old and it still sounds amazing. 
Burson V6 Vivid and V6 Classic did not do the trick for me, the OPA627 sounded superior. A friend of mine suggested they were probably under-powered in my DAC.
Is there a modern upgrade to the OPA627 that is known to sound superior? It needs to be an op amp that fits straight into the socket without any modifications.
I love warm, natural and dynamic sound but I would not mind a change if there is an op amp available with higher resolution maybe?
Most threads concerning the OPA627 are rather old...any ideas?
Cheers


----------



## sp33ls (Mar 7, 2022)

OPA828 is the modern successor to the OPA627. Well, technically the 827 was the original successor, but the 828 has since replaced it, and it seems the 828 is preferable to the 827 from those who have tried both. I've not tried the 627, so I can't speak to that comparison.

I'm currently using dual OPA828 on this adapter within my upgraded WHAMMY, sounds awesome.


----------



## zachgraz (Mar 7, 2022)

OK there are 4 single channel OPA627 in my DAC. Would I even be able to use the OPA828 in my setup - I would have to solder it to an adapter too I guess? I have found plenty of dual channel 828s on Ebay but no single channel adapters.


----------



## sp33ls

You'd need to order four of these then:

https://www.cimarrontechnology.com/product/browndog-970601-so8-to-dip8-adapter

You can select the OPA828 (or another) from the drop-down list, and you'd want to select "pins are installed." This would result in four opamps being installed and ready to go, no soldering required.

I've ordered several of their pre-installed adapters and have had 0 issues.


----------



## wein07

zachgraz said:


> Hi folks,
> maybe you can help me with an upgarde to my OPA627 in an Ayon Skylla 2 DAC. The DAC is now 10 years old and it still sounds amazing.
> Burson V6 Vivid and V6 Classic did not do the trick for me, the OPA627 sounded superior. A friend of mine suggested they were probably under-powered in my DAC.
> Is there a modern upgrade to the OPA627 that is known to sound superior? It needs to be an op amp that fits straight into the socket without any modifications.
> ...


I would suggest u try the Burson V5i instead. It worked very well across many platforms in my experience, from DACs, soundcards and speaker/headphone amplifiers.


----------



## John Massaria (Mar 30, 2022)

the 627 is a fine chip worthy of going down in history as one most pleasing all rounder - many others I have tried wound up being nice and detailed but lacked the warmth of the 627bp - the successor for me was the 1611a (seen below on SOIC-8 to 8-pin DIP) which was used for super sensitive sonar equipment in the early 2010's
the opa1611A left me wanting more so I bought a ton more opas, and the fully discrete SS3601 by Sparkos was way too detailed and sometimes fatiguing on some poor recordings - a true reference chip set BUT in my Ray Samules Apache just too much- I wound up getting and loving the Sparkos ss2590s x 4 - but dollar for dollar the 627bp was so warm and enjoyable... but for the most balance of all the SS2590 wound up winning









This is what I wrote from this article https://www.head-fi.org/showcase/ray-samuels-apache-limited-revision-4-updated-1-10-21.24732/

* "SPARKOS* *SS3601 Single Discrete Op Amp - and I can say it sounds great on top end (if a wee bit too much sparkle on high spectrum frequencies- a bit too much - think hyper Analytical on top end. It's not exactly sibilant but close-  The 6kHz to 16kHz range controls the brilliance and clarity of sounds and seems very highlighted here on Sparkos ss3601 )  - this is the truth of what I hear for me but lower end is not close to OPA1611 - the 1611 for me sounds best so far- with  Attack  much more refined. I do plan on buying a few more OPA's and updating. For now the SS3601 x 4 is not as musical as the OPA1611 x 4. I do plan on trying the SPARKOS pro SS2590 discrete op amp. *

*I am now using the OPA627bp and it is an amazing warm loving amp now- more impact than Sparkos BUT I need to continue tests. For now- there is no doubt the Apache is a complete chameleon and truly a state of the art design - so quiet and so powerful with no matter the chips installed- but its like getting a new amp sound- very appealing to me. I love the OPA627bp for all it's musical presence and bass impact. It's a lovely sound and it deserves high praise and should be regarded as one of the best OPA's ever made in the last 30 years and probably will stay that statement for the next 30. But I need to continue testing-
just installed 4 SS2590 - and my impressions are complete bliss- warm impact definition and authoritative- a very very great match inside the Apache. The OPA627bp was one of my favorite OPAs for it's shear musicality and ability to loose yourself in the music- never hyper analytical or soft from one end to the other- BUT the SS2590 brings the Apache to a new level of pleasure- past the OPA1611 I originally tested throughout this article. I am listening to Damien Rice and astonished at the pure synergy of matching- this fully discrete high powered Class A Opa is the bees knees-

I am loving each and every second with this combination (SPARKOS PRO SS2590x4 + RSA Apache).  Sparkos writes this when comparing IC OPAs to discrete OPAs, "Discrete op amps do not have these limitations, and are a vastly superior  upgrade over their IC counterparts.  They can run much higher power, have much deeper class A bias, and deliver a much more realistic and detailed sound.  Discrete op amps also permit the use of high quality compensation capacitors, and allow for two pole compensation schemes which are impossible to implement in IC designs. All of this translates into a more detailed and engaging listening experience with better imaging and sound-staging than IC op amps can deliver." I 100% agree- this combination is VERY much my ideal set up bringing the Apache to the brink of perfection and I think it's very limits of performance - truly amazing sound. Again, track after track this SS2590 combo is so good I can not stop listening. It's a pure addiction where there are are zero calories, zero chance of anyone getting pregnant, literality zero side effects and no repercussions for inducing a drug like stupper endorphin rush and  injection of pure bliss - all my senses tell me this is the ultimate combo I will like the most. And it's only been a few hours since I installed this OPA. I will be doing more comparisons in this review to the other OPAs- namely going back to the 627bp and the 1611 but it may just be futile as my first impressions usually are my best- but we will continue to test..."


*


----------



## zachgraz (Mar 8, 2022)

sp33ls said:


> You'd need to order four of these then:
> 
> https://www.cimarrontechnology.com/product/browndog-970601-so8-to-dip8-adapter
> 
> You can select the OPA828 (or another) from the drop-down list, and you'd want to select "pins are installed." This would result in four opamps being installed and ready to go, no soldering required.


Thank you for your great suggestion! I could not find any single OPA828 on DIP8 on Ebay. So I just ordered 4 of them through your link.



wein07 said:


> I would suggest u try the Burson V5i instead. It worked very well across many platforms in my experience, from DACs, soundcards and speaker/headphone amplifiers.


Thank you too. I will order them too once I have found a supplier in the EU (EDIT: I have ordered vom Audeos Poland).

OPA828 and Burson V5i seem to be worthy contenders for the OPA627. I will keep you updated once I am through with comparing.

Thank you all for great suggestions!


----------



## SoundDouble

Hello head-fiers. Burson reached out to me and giving me the opportunity to try out some of their opamps.
I know plenty of people have reviewed them already but once I'm done I will post up the link.


----------



## wanted110 (Mar 24, 2022)

Hi everyone. Is there a page in this topic or somewhere else on headfi where we could fine a side-by-side review of many opamp ?
I am thinking OPA6X7, MUSES0X, LME49XXX, AD797 and maybe some V5/5i/6 and other discrete product, all in one go ?


----------



## Themilkman46290

wanted110 said:


> Hi everyone. Is there a page in this topic or somewhere else on headfi where we could fine a side-by-side review of many opamp ?
> I am thinking OPA6X7, MUSES0X, LME49XXX, AD797 and maybe some V5/5i/6 and other discrete product, all in one go ?


Op amps are very dependant on the circuit around it, they change drastically depending on what you put them into, the chart would need to be re done for every amp, player or receiver you put it into, it would probably take years to figure this out. Not to mention people's individual taste and hearing abilities.


----------



## wanted110

Themilkman46290 said:


> Op amps are very dependant on the circuit around it, they change drastically depending on what you put them into, the chart would need to be re done for every amp, player or receiver you put it into, it would probably take years to figure this out. Not to mention people's individual taste and hearing abilities.


I understand that. I am just curious to get some reading.
Well then, something more realistic : What would you upgrade a Muses02 with ?


----------



## Themilkman46290

I really enjoyed the v5i but my favorite was the dual lm49710 ha but there really difficult to get these days


----------



## sp33ls

Really does depend on the surrounding circuit.

I will say, tho, the WHAMMY HPA is probably the component which illustrates any differences between opamps tho most. I've had situations where I couldn't honestly tell a difference between opamps. Not only is the WHAMMY a superb amp, it makes for a great test bed for opamp rolling as I can consistently detect subtle differences with this circuit (using the opamp for I/V duties)


----------



## Sam Spade

John Massaria said:


> the 627 is a fine chip worthy of going down in history as one most pleasing all rounder - many others I have tried wound up being nice and detailed but lacked the warmth of the 627bp - the successor for me was the 1611a (seen below on SOIC-8 to 8-pin DIP) which was used for super sensitive sonar equipment in in the early 2010
> the opa1611A left me wanting more so I bought a ton more opas, and the fully discrete SS3601 by Sparkos was way too detailed and sometimes fatiguing on some poor recordings - a true reference chip set BUT in my Ray Samules Apache just too much- I wound up getting and loving the Sparkos ss2590s x 4 - but dollar for dollar the 627bp was so warm and enjoyable... but for the most balance of all the SS2590 wound up winning
> 
> 
> ...




"*It's a pure addiction where there are are zero calories, zero chance of anyone getting pregnant"*

Unless you have two sets of headphones going......   listening to something romantic


----------



## zachgraz

sp33ls said:


> You'd need to order four of these then:
> 
> https://www.cimarrontechnology.com/product/browndog-970601-so8-to-dip8-adapter
> 
> ...





wein07 said:


> I would suggest u try the Burson V5i instead. It worked very well across many platforms in my experience, from DACs, soundcards and speaker/headphone amplifiers.


Hi folks, I promised to give feedback so here it is. I received the V5i and ended up using it together with the OPA627 (I have 2 single OP amps per channel in my Ayon Skylla 2 DAC). It was a great combination with good dynamics but also a kind of "thicker" sound because of the V5i. They complemented each other very well, 2xV5i or 2xOPA627 did not sound as great.
Then I received the OPA828. It has more resolution than the OPA627 and in my case better instrument separation and soundstage. There are simply more details and it sounds more dynamic but also a bit brighter. The downside I found was that OPA828 had less lower mids, which made the OPA627 sound a bit fuller and warmer. I use EQ in my system anyhow and I increase the levels in the lower mids which gives me the same "full" sound as the OPA627 has. With that little EQ trick the OPA828 is simply a better OP amp in my opinion. The OPA627 sounds less defined and more blurry in comparision.
Now I am using pairs of V5i and OPA828 with great results. So both suggestions from you guys have been helpful. Thanks a lot for that.


----------



## sp33ls

You may actually find additional improvements with the addition of a couple 0.1uF bypass film caps near the opamp socket (across V+/GND and V-/GND).

The  OPA828 datasheet calls for bypass caps. And I know Burson advises the use of a film cap across V+/V- for the V6. Just figured I'd call that out


----------



## DAPpower

I'm new to op amps but I have had very good results with 2x Dual SPARKOS PRO SS2590 and 2x Sonic Imagery Labs 994Enh-Ticha on my Burson GT amp. The combination of the Sparkos and SILs really made the amp more resolving and the amp I feel, became more tonally correct. The music became more engaging compared to stock op amp chain.


----------



## justsomesonyfan

new to op amps, if my portable amp has a section for a dual opamp and a section for 2 single op amps, can i mix them? meaning 1x dual and 2x single?


----------



## SoundDouble

justsomesonyfan said:


> new to op amps, if my portable amp has a section for a dual opamp and a section for 2 single op amps, can i mix them? meaning 1x dual and 2x single?


If you mean that it takes 3 opamps in total, then you probably want to keep the 2 singles equal to each other

and the dual you can be something different from the singles.


----------



## justsomesonyfan

SoundDouble said:


> If you mean that it takes 3 opamps in total, then you probably want to keep the 2 singles equal to each other
> 
> and the dual you can be something different from the singles.


yeah, 1 dual and 2 singles, read the manual and the amp maker advised not to combine, so i guess i'm going for either 2 singles or 1 dual  is there any consensus op amp models that are known for being better than others? sorry for the amateur talk, but i'm super new to this, my amp opamp section can accept 8 pins (4 on both sides) and does not have much room for a tall op amp (apparently those exist!), for example something like this:


----------



## SoundDouble

justsomesonyfan said:


> yeah, 1 dual and 2 singles, read the manual and the amp maker advised not to combine, so i guess i'm going for either 2 singles or 1 dual  is there any consensus op amp models that are known for being better than others? sorry for the amateur talk, but i'm super new to this, my amp opamp section can accept 8 pins (4 on both sides) and does not have much room for a tall op amp (apparently those exist!), for example something like this:


I would start by posting what opamps are installed originally. That might help direct which way to go. And search, if you haven't already, for those opamps to see comparisons people posted. Will give you some ideas. That's what I did.


----------



## justsomesonyfan

SoundDouble said:


> I would start by posting what opamps are installed originally. That might help direct which way to go. And search, if you haven't already, for those opamps to see comparisons people posted. Will give you some ideas. That's what I did.


it uses MUSES01 op amp, i'll be honest the amp actually gives really, REALLY good results, just wondering if i could take it even higher  i've heard good things about the burson v5id


----------



## SoundDouble

justsomesonyfan said:


> it uses MUSES01 op amp, i'll be honest the amp actually gives really, REALLY good results, just wondering if i could take it even higher  i've heard good things about the burson v5id


I dont have experience with the muse but have seen online that they are pretty good. If you have the money to buy the burson v5i dual and see if you like the change. Remember its not just the opamp, but how does it match with the rest of the amp and the headphones you're using. 

Good luck


----------



## justsomesonyfan

SoundDouble said:


> I dont have experience with the muse but have seen online that they are pretty good. If you have the money to buy the burson v5i dual and see if you like the change. Remember its not just the opamp, but how does it match with the rest of the amp and the headphones you're using.
> 
> Good luck


yes thank you, i might mod the casing and get the big v6 in there


----------



## carlmart

By portable amp you mean headphone amp?


----------



## justsomesonyfan

carlmart said:


> By portable amp you mean headphone amp?


yes, a portable hat amp add-on


----------



## SlothRock

Just did my first op amp roll into my Burson 3X GT. I got 2 x dual SS2590’s in the volume control buffer stage, 2 x SIL 994 Enh’s in the input buffer stage and kept the V6 Vivids in the voltage stage. 

Made quite a big improvement IMO. The two most obvious differences I’m seeing are detail retrieval, way more of a neutral sound and better impact. I haven’t tried any other combos so far but glad I took the leap and decided to do this. Really liking the change in sound


----------



## sparko311

Nice... Looks good!


----------



## justsomesonyfan

question, what op amp has the biggest soundstage?

and wondering, are class A op amps good?


----------



## sp33ls

justsomesonyfan said:


> question, what op amp has the biggest soundstage?
> 
> and wondering, are class A op amps good?


Class A is an amplifier topology, so there's no such thing as a "class A device," rather it's whether the device is operating in Class A mode.

I think this is what you meant, and my opinion is yes, the couple of examples I've heard with opamps in Class A amps are superb.

Tho, I still prefer opamps for voltage gain purposes as opposed to using them as an output stage coupled to transducers.


----------



## justsomesonyfan

sp33ls said:


> Class A is an amplifier topology, so there's no such thing as a "class A device," rather it's whether the device is operating in Class A mode.
> 
> I think this is what you meant, and my opinion is yes, the couple of examples I've heard with opamps in Class A amps are superb.
> 
> Tho, I still prefer opamps for voltage gain purposes as opposed to using them as an output stage coupled to transducers.


thanks!


----------



## Setmagic

justsomesonyfan said:


> question, what op amp has the biggest soundstage?
> 
> and wondering, are class A op amps good?


Soon we will see more Class D Hi-End solutions than ever before.
This topology of amp if very power efficient and small according to A and AB class devices but also it's more difficult to run it sound as good as A but it's possible, especially using modern parts.


----------



## dharmasteve (May 18, 2022)

I didn't know there was a dedicated opamp thread. Better late than never. I'm one of the older guys on Head-Fi, grew up with vinyl. Never did have the money for the exotic brands but I remember I really got into the early Dual 505 turntable, Goldring cartridges, and a bit later Musical Fidelity amps in the 80's. I got big time OCD over little T-Amps back in their day. I'm definitely an old analogue-man, lover of World Music and almost everything else musically. In July of 2019 I bought the _*Little Bear 4-X hybrid tube amp*_ and have used it on and off ever since. Lately I found the Little Bear a good match with the Shuoer S12 Planar IEM and got back into using it.
A few weeks ago I got a message from Burson Audio asking me if I would like to compare the Burson V5i-D-2 opamp with the stock opamps. I've never been a compulsive Modder, but when necessary I'm up for it. The Little Bear looked simple enough so I found the idea interesting. I had no idea of any difference a new opamp would make to the sound, I'd never changed one before on the Little Bear. So armed with some small Allen Keys, some tweezers and a shaky hand, I got going. It turned out so simple to take the board out, take out the stock opamps and put the more substantial Burson's on.
The opamps had arrived a while ago, so I started to deliberately use the Little Bear 4-X most of the time to get back familiarity with the sound. That meant constant charging because the built in battery does not have the longest play time (about 5 hours). I chose a few songs to really mainly concentrate on... 'Stimela', live, _Hugh Masekela_ and 'Shovelheads', _Shriekback_ (Yep a bit left-of, but has a lot going on), and the great 'Grandpa's Interview',_ Neil Young_. From _Patti Smith_, 'We Three', and also _New Model Army's _'You weren't there'.
When comparing and A/B-ing *IEMs* there is a simplicity to hear the differences. Generally just take one off and put the other on. It takes just a few seconds. Even then there has to be the memory of the previous moments. The moments are close enough to get a fair idea of the differences. When changing *opamps* through there is more time involved in the change so the gap in listening is longer, so possibly more deceptive. It's useful to write keywords down to keep impressions fresh. So what I write here can be taken with a pinch of subjective salt.
Before listening I left the 4-X to warm up for 15mins. First thing I noticed with the Burson, seemingly more RF interference. More sensitive obviously, but that can be good in the long run. Not a problem for me, maybe for some. For me once the music starts this old guy cannot hear the RF so no problem.
Compared to stock the Burson's are less generally fuzzy, and have a much cleaner sound. Leading edges of guitars and drums are more defined and precise, sub-bass is cleaner without losing rumble. A subjective feeling of musicality arises whilst listening with the Burson V5i-D-2's.
_Patti Smith's_ wonderful voice becomes richer, thicker and smoother, yet cleaner in 'We Three'. Same with _Hugh Masekela's_ voice in 'Stimela' and the instruments too. On 'Grandpa's Interview' from the 'Greendale' project, _Neil Young_ has more resonance on the lower register guitar strings, and a kind of mini vibrato all the way through plus great cymbal crashes later in the track.
There is little doubt the Burson opamps are noticeably different in sound to the OG's. It surprised me that a little opamp can make such a difference. The Burson's are here to stay in my Little Bear and easily give me a large dose of extra enjoyment.

IEM used, *IMR Splash of Gold *open back, *Spiral Dot L* tips. _*Sony Xperia 5ii*_ phone.


Attachments​



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## Stingray5funk

Here’s a new one… I have a bass guitar with an onboard preamp..

Used a TL062CP
Can I upgrade to anything better?
TLE 2082CP

Runs off 18v battery for power for the pickup and power to the preamp


----------



## carlmart

Stingray5funk said:


> Here’s a new one… I have a bass guitar with an onboard preamp..
> 
> Used a TL062CP
> Can I upgrade to anything better?
> ...


I'm afraid there might not be much of a difference. You can do this: unsolder the chip and put a dip-8 socket. The main problem is that better ICs usually lower th noise, and a bass guitar preamp is noisy by nature. But you can try other dual IC DIP-8 types and listen if there's any difference to your ears.


----------



## sdubrae (Sep 3, 2022)

Hi I'm looking for some advice on rolling opamps on my headphone dac. It's a KECES DA-152 an older model from around 2009. I've included a picture of the board. It has 5 opamps in total they are all LME49710NA 8 pin PDIP.

I've marked them A, B, C By looking at the board can someone break down what they do and which I might swap? I'm most interested in changing the sound signature/flavor of the RCA pre out if that's possible.

Also any opamp recommendations would be welcome.


----------



## dhruvmeena96

Hi guys, after a long time on this thread..

@Burson B  sent me these opamp to test 
V6 vivid

Sorry, i was not able to make my own custom project because having very high fever

But was able to get a swap done on my friend DX7 pro

Sounds amazeballs good. I mean its actually noticeable to the point that if someone has audio precision, i really want to measure what is causing it.
It just makes things more clearer.

But in my diy infected head, i think these opamp deserves its own design 
Once i get well, i will try to conceptualize and build an amp from scratch

Kinda based on Cmoy with some tweaks here and there


----------



## zachgraz

Hi folks,
I have a Burson Conductor 3X Performance headphone DAC AMP which is equipped with 4 Burson V6 Vivids.
I love the sound alltogether but there is one downside - the bass is not precise enough for my taste.
The V6 Vivids give an amazingly clean but also smooth sound that is addictive. The soundstage is amazing.
The bass sounds a bit loose and does not have enough punch with my Meze Elites. When I change the opamps behind the XLR sockets to JRCs that also came with the Conductor 3XP bass becomes clean and punchy but this opamp is not as musical as the Bursons.
What can I do? Is there an opamp out there with musicality similar to the V6 Vivids but with better bass punch?
Maybe the V6 Classic? Anthing else like OPA1656 or OPA828 in a dual adapter?

Interestingly in my Ayon DAC OPA828 blew the Burson V6 Vivid and Classic away soundwise and is the one I ended up using. Those were single channel opamps - I need dual channel opamps in the Burson amp.


----------



## FritzS

dhruvmeena96 said:


> Hi guys, after a long time on this thread..
> 
> @Burson B  sent me these opamp to test
> V6 vivid
> ...



Only a suggestion for you, this headphone amp works well since 2006.
http://www.blue-danube.at/hifi/wna-main.php


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## dhruvmeena96

FritzS said:


> Only a suggestion for you, this headphone amp works well since 2006.
> http://www.blue-danube.at/hifi/wna-main.php


Thenks bruh


----------



## justsomesonyfan

question, my r2r2000 dap is using a pair of opa1642 which I want to replace with a different burrbrown chip, I've been wondering, which opa is the best / most advanced that could fit? I've been looking at the opa2107, but there are so many models I'm seriously confused.


----------



## Ghoostknight

sad to see this thread die over the last 2 years, where are all the op amp rollers? 
i had a lot fun rolling opamps in my old topping d10 where the OPA1656 followed by the OPA1612 sounded best in my opinion, i also had this capacitor mod from here a few years ago, Nichicon KZ 10uf sounds the best, nice flat and deep fast bass! 

Did anyone try a 10uF Cap + a 0,1nF MKP cap?

i also bought the Aune X8 XVIII last week just because it seems one of the best "budget" dacs that have a op-amp socket! x)
the default JRC 5532DD sounds very analytic a little fatiquing tho but i was really impressed with the performance compared to my FIIO E10k TC, Instruments sounds very nice with it but rock/metal is very fatiquing with it
i also tried the OPA1656 here and it sounds "sweeter/smoother" with more deep bass and alot less fatiquing but not as natural i would say

DId anyone try opamps in an Aune X8 ?


----------



## John Massaria

I’m still loving my sparkos ss2590s


----------



## bust3r

Not a whole lot of units are coming out with swappable opamps anymore.  I have quite a few that I can’t use now that I’m not sure what to do with.


----------



## carlmart

justsomesonyfan said:


> question, my r2r2000 dap is using a pair of opa1642 which I want to replace with a different burrbrown chip, I've been wondering, which opa is the best / most advanced that could fit? I've been looking at the opa2107, but there are so many models I'm seriously confused.


You might try looking at the specs of several chips, not just OPA, and see how they compare. Particularly distortion, noise and slew rate. And looking for people using the new ones. Put sockets if you can, and then compare them. Turn it off the equipment before plugging in or out. Be careful with the max voltage in the new chips. Sorry if this sounds too basic, but I don't know how experienced you are.


----------



## carlmart

bust3r said:


> Not a whole lot of units are coming out with swappable opamps anymore.  I have quite a few that I can’t use now that I’m not sure what to do with.


Yes, SMD soldered chips ruined the fun. But you may try using the now common balanced outputs found on some DACs and use an outboard pcb with its own separate supply. And put DIP-8 sockets on it.


----------



## sparko311

Aiyima has a series of amps (A07 and A08 for example) that allows for op amp rolling.  Those are pretty hot right now.


----------



## JAnonymous5150

Today I should be receiving my 4 x V5i order from Burson so I can install them in the ES9038Pro based DIY DAC/amp combo I built. For now it has MUSES8920s or OPA1622s on DIP8 adapters in it depending on on what I'm plugging into it as they both provide a pretty distinct listening experience and match better with different headphones, IEMs, and earbuds.

I'm planning to order a set of Sparkos op amps to try as well, but I haven't done my research yet to figure out what I'm going with.


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## redrol (Nov 16, 2022)

Sparkos Pro SS2590.  End game.  Laters anything else.  This is a modified Gishelli JNOG2.


----------



## ekjellgren

redrol said:


> Sparkos Pro SS2590.  End game.  Laters anything else.  This is a modified Gishelli JNOG2.


What's that strange cable to the left? SPDIF?


----------



## redrol

Yeah just a clear spdif optical cable.


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## ekjellgren

Just placed an order for dual SS2590 for my Soloist 3XP, good times ahead testing that!


----------



## AJCxZ0

For reasons which may involve me being unable to count to two or understand how to use AliExpress, I placed a second order which should result in me receiving four DIP-8 extenders of which I only need two. These appear to be the same as the ones which Burson has on sale for slightly more money.




If you are reading this some weeks hence and need a couple of these to try to jam your V6s into anything smaller than a shoe box and don't want to wait for them to arrive from China, then I may have two tested spares, though it may cost more for me to mail them to you than the vendor because... economics.


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## ekjellgren

Cool. I thought I'd order those from Burson. Initially I hope to get by with a couple of these though, https://sparkoslabs.com/product/dip-socket-riser/
Seen in a video by Michael Bruce, , I hope it will do in my Soloist 3XP as well.


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## redrol

Nice!!  Thats me Michael Bruce   Do it!! They are all that and a bag of chips


----------



## Onik (Nov 29, 2022)

Anyone tried Sparkos Pro SS2590 in Burson Playmate 1?

I assume fit is the real problem, but maybe I can fit them in I/V stage with adapters...🤔


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## Ghoostknight

im also interested in any opinions about the Sparkos SS2590 with dual dip8 adapter, especially vs the Sparkos SS3062


----------



## Onik

SlothRock said:


> Just did my first op amp roll into my Burson 3X GT. I got 2 x dual SS2590’s in the volume control buffer stage, 2 x SIL 994 Enh’s in the input buffer stage and kept the V6 Vivids in the voltage stage.
> 
> Made quite a big improvement IMO. The two most obvious differences I’m seeing are detail retrieval, way more of a neutral sound and better impact. I haven’t tried any other combos so far but glad I took the leap and decided to do this. Really liking the change in sound


Why you kept V6 in I/V stage?


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## sawindra

hello..there is no i/v stage in soloist 3x GT.


----------



## Onik

the what stage is that?


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## sawindra

voltage


----------



## John8546

Hello everyone, I have a question about Sparkos SS2590, is it possible to replace OPAmp MUSES03 with two Sparkos2590 in a DAC??? There is now an option to plug them in DIP8, has anyone tried it??? I ask this question because the minimum supply voltage is +9V compared to the minimum voltage for the MUSES03 which is +3.5V. I am waiting for your answers before ordering 2 X SS2590, it is to be sure that it will go in my DAC (Dual AK4499). Today I replaced the MUSES03 with BURR BROWN OPA627AP and I prefer the sound with the OPA627AP. Will it be better with SS2590??? It is worth considering.....


----------



## Ghoostknight

Hello, 

i just compared my current favourite opamp opa1656 vs the much older opa627 (its a dual module from audiophonics, the IC`s are "used" if this matter but as long they function correctly i only see the benefit of them being already burned in ) i tested these with the Aune X8 XVIII

on first sight i would say the opa627 has these attributes compared to the opa1656 
- sounds somewhat thinner, voices sound more lean but at the same time a bit more sibilant
- you could say its a bit more analog sounding
- not so bass heavy as the opa1656 (the 1656 really shines in bass regions, specially infrasonics are much more "audible")
- im not a huge soundstange "comparer" but maybe its a bit more 2d but wider sounding
- highs (over 10-12khz or so) not as "sparkling" as with opa1656 (but at the same time more sibilant, not overly sibilant but with the opa1656 sibilant nearly "vanishes" while the opa627 brings them a bit up again, it doesnt "shoot" sibilance in your face, its just a bit more audible)

im just listening right now for 1h so take these descriptions with a grain of salt but it sounds interesting, i wouldnt say it sounds "worse" to the opa1656 but just a bit different, the first thing i thought was "ah this is how old stereos may sounded compared to modern equipment"

(both opamps were tested with a Nichicon KZ 10uF bypass capacitor between V+ and V-, i heared with all opamps i tested improvements with the bypass cap, tho i didnt tested it specially with the op627, imagine the change a bit what the opamp itself does but just a touch better with bypass capacitor )

would these discription line up with what you guys heared?

im looking forward to compare to the sparkos discrete opamps somewhat soon


----------



## AJCxZ0

AJCxZ0 said:


> I placed a second order which should result in me receiving four DIP-8 extenders of which I only need two.


The first extender arrived, so I was able to assess the options for fitting the pair of Burson V6 Vivid opamps in my Fosi Audio P1 tube pre-amp. Alas, there is only space for one with the case closed.





See the album for the answer to all the question of fitting in the other apparent spaces.
The mixed blessing is that I will finally be able to test the V6 Vivids in the P1 like




which I tested with the original TI NE5532Ps, but not keep them.

With a DIP 8 riser, I think I may be able to fit a pair of SS3602 Dual Discrete opamps between the tops of the caps and volume pots and the case.


----------



## ekjellgren

How many have actually fried a headphone amp switching opamps?
I've just recieved a pair of Sparkos SS2590, and Burson is warning me of customers that have had their units burnt.


----------



## JAnonymous5150 (Dec 15, 2022)

ekjellgren said:


> How many have actually fried a headphone amp switching opamps?
> I've just recieved a pair of Sparkos SS2590, and Burson is warning me of customers that have had their units burnt.



I never have. Basically, as long as you've gotten op amps that are designed to function within the parameters of a given amp's circuitry, there would have to be something faulty with the op amp itself for any kind of meltdown to happen. Now, if you're not sure how to determine which op amps are capable of operating in your particular amp and you don't have anybody qualified to ask then shoving random op amps in expensive equipment can have consequences.

I don't want to speak for Burson, but my guess is that as a manufacturer they will always tell you not to use third party op amps or to do so at your own risk because they have no control over the QC of those amps or the accuracy of the info you're giving them so tacitly approving your use of third party op amps could potentially open them up to being liable for any damage caused by their use. Any reasonable company isn't going to do that if for no other reason than to cover their backsides. That said, Burson may have other specific concerns with Sparkos in particular (discrete op amp designs can come with other issues/complications), third party amps in general, or whatever that is also a part of them answering the way they did. In general, I have always found the few folks I have dealt with at Burson to be pretty open and honest so if they're telling you that they have reports that these situations have happened, then I'd believe them as I have no reason not to.

If you're not confident about doing it I wouldn't unless there are other folks out there using the same op amps on the same Burson model successfully AND you're willing and able to deal with any potential consequences from some sort of meltdown/epic fail situation.


----------



## Ghoostknight

i think you really just have to be careful with discrete opamps, they seem to draw quite alot of current compared to chip opamps, probably specially the Sparkos SS2590


----------



## ekjellgren (Dec 16, 2022)




----------



## ekjellgren

I guess it's a matter of lining the half round notch in the opamp and the socket?


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## Ghoostknight (Dec 16, 2022)

ekjellgren said:


> I guess it's a matter of lining the half round notch in the opamp and the socket?


yes, tho there should be a marking on top of the SS2590 too (to make sure, take a look at the manual which can be downloaded to see where the marking is exactly)

Edit: here you go https://sparkoslabs.com/wp-content/uploads/2020/09/ProToDIP_Dimensions.jpg


----------



## ekjellgren

I got them to work!
Only for a short while though.
After about a minute I heard som noice and the left channel went silent.
I reconnected the V6’s and everything was fine. So nothing broken in the amp/headphones anyway.

My impression is that the opamps sit quite loose in the sockets, and I guess it’s the one I connected without the raisers that went silent.
How could I get them to sit more tightly? Should I bend the pins or something?

I’ll try tomorrow and use them both with raisers just to verify they are ok, but my heart can’t take more drama for today =)


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## Ghoostknight

ekjellgren said:


> I got them to work!
> Only for a short while though.
> After about a minute I heard som noice and the left channel went silent.
> I reconnected the V6’s and everything was fine. So nothing broken in the amp/headphones anyway.
> ...


the dip sockets are quite fragile and not really made for many inserts, best would be to replace them if they went too lose 
but i guess you can also bend the pins a little to get a tighter contact as a kind of workaround


----------



## AJCxZ0

AJCxZ0 said:


> The mixed blessing is that I will finally be able to test the V6 Vivids in the P1...


The other three extenders arrived, so in order to test them and the Burson V6 Vivid opamps in my Fosi Audio P1 tube pre-amp, I started with the extenders and the included TI NE5532P opamps.








With 96 kHz PCM from the PC to the Topping E30 and output from the L30 (of which there are now a version two of each), I casually listened to a variety of tracks of varying quality and type, occasionally twiddling the bass and treble knobs, listening with my Sivga SV021 "Robin" using my ears and being reminded again that this cheap little tube pre-amp is excellent value and does not go wrong.

With the devices powered off, I carefully swapped the IC opamps for the V6 Vivids and listened again to the track to which I was last listening: a 24 bit 96 kHz Wave file of Movement IV from Beethoven's Symphony No. 9 in D minor, Op. 125, performed by _Anima Eterna Brugge & The Australian Brandenburg Choir_ courtesy of RØDE followed by the newly released Tenebre Rosso Sangue from KEYGEN CHURCH.





With all the other components in the signal path and the lack of even an attempt to A/B test, not to mention all my biases, I am hesitant to give any impression of the difference between these two opamps, however the significant initial impression I got was that the sound became more intense, revealing and dynamically expanded.

With the Vivids installed, I plan to listen to more tracks of varying quality and type, occasionally twiddling the bass and treble knobs, listening with the Robin and my other headphones before switching back to the NE5532Ps to get another impression.


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## TheManko (Dec 20, 2022)

In case anyone is in Japan, MUSES05 is now available on sale. https://www.nisshinbo-microdevices.co.jp/ja/MUSES/series/MUSES05.html Unlike previous MUSES op amps, it's a SMD style op amp. But for DIY purposes there is a version pre-mounted on a DIP8 adapter. So far, this is the only store where you can buy it: https://akizukidenshi.com/catalog/g/gM-17651/

I'm pretty excited about the MUSES05, because I have a lot of experience with the previous MUSES models. I'm currently using MUSES03 in the input stage of my Purifi 1ET400A speaker amplifier. Before I broke my Essence III dac, I did extensive op amp swap testing, doing careful listening for hours and hours for years. The number of comparisons and tests I conducted is easily over two hundred, as I owned the dac for nearly ten years. I have tried every version of the OPA627, including the metal can version, the AD797, AD827SQ, AD847SQ, OPA828, Sparkos SS3602, Burson V6 Vivid, OPA1611, OPA2156, and many many others. In my experience the OPA828, SS3602 and MUSES03 are easily the best I've heard, regardless of whether they're used in the Essence III dac, or in the Purifi amplifier. Note that I haven't tried the larger SS2590, or other similar larger discrete op amps. After what I've heard with V6 Vivid and SS3602 I expect the SS2590 is superb. SS3602 gets a lot of things right, but it's a bit crude in the finer details, with diffuse bass and a grainy character to the sound. In isolation these flaws might not be obvious, but compared with say OPA828 these imperfections become clear.

Of these top three my favorite is MUSES03. It has a style of sound that seems to evoke more emotion and make the music more enjoyable than the others. OPA828 feels like the most technically correct presentation of the sound, done at a far higher level of quality than say LM4562. But it's a bit emotionally distant compared to MUSES03. For me it's important that the sound evokes an unexpected and involuntary emotional response. MUSES01 was also good at this trick, but it's far inferior in quality to MUSES03. MUSES01 is not in the same top tier level of performance. In my experience, older op amps sound like old outdated technology compared to newer ones. The entire OPA627 line sounds obsolete compared against OPA828. Newer op amps provide a far more detailed and precise sound, which in turn also results in a broader tonal range. But of course, how they're implemented and how they interact with the sound system as a whole makes all the difference. MUSES03 is/was a huge improvement over MUSES01 and MUSES02, like how OPA828 is on another level compared with OPA627. This is what makes me curious to try the MUSES05. Will they have made meaningful forward progress in the quality of sound, while still retaining the charm of the MUSES line? I'd buy them, but the only store that sells them doesn't accept international orders.

Hope this was interesting to someone.


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## sawindra

Muses suprised me a lot


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## Ghoostknight (Dec 31, 2022)

Ghoostknight said:


> im looking forward to compare to the sparkos discrete opamps somewhat soon


well it ended up as a Burson V6 Vivid 

these are my first impressions compared to the dual OPA627 im using until now and reviewed earlier in post #7216 where i compared the dual opa627 against the opa1656
(the V6 isnt burned in yet)

- it sounds more quite, you have to give it a little more volume
- bass is stronger and i would say sounds more accurate and has more "punch", i think this is also the strongest difference to the OPA627
- voices sound -very- smooth and natural
- overall it has a nice presentation, i would say it sounds more 3D with a bit more narrow soundstage, specially in comparision to the OPA627 which sounds more 2D with a very wide soundstage
- it has very nice natural sibilance, -you hear the sibilance- but it sounds somewhat natural (imo sibilance always sounds artificial because its mostly because of mics)
- older recordings sound very nice, i tested a 1960s track, the V6 brings up some of the "retro sound" in these recording
- instruments also have a nice natural character
- highs sound more sparkling again, which i missed with the OPA627
- i expected a bit more, maybe i was a bit hyped because its my first discrete opamp but on the other side it still sounds very nice, and probably the best opamp i heared
- way less listener fatique even at higher volumes, actually it sounds very pleasing to listen to

overall i would say, it sounds very natural and "coherent" across the board, im specially surprised over the punchy bass
i already heared burn in after a few minutes, but i will give it of course more time 

i also tried my default Nichicon KZ 10uF bypass capacitor, it nearly sounds like it lifts of a veil above the music, more dynamics, clearer and even more natural overall sound describes it the best i think, i can only suggest all people that are opamp rolling also to try bypass capacitors, i tried a few electrolytics so far and the Nichicon KZ sounds best/most flat to me

there will be a complete review somewhat soon after i bruned in the V6 a bit if someone is interested 

Edit: 
after around 40h of burn in, the most obvious things:
- a little more cohorent/natural
- i specially really like the sound of "retro mics", the V6 does some kind of magic with "older" recordings (for example Nancy Sinatra - These Boots Are Made for Walkin`)
- treble/highs got VERY nice, way more pronounced than with the OPA627 without being annoying, it sounds very detailed in the upper regions (probably >5k hz)
- i think the punchy bass i heared before is a little more laid back now, overall it sounds more neutral now imo

looking forward what 100-200h burn-in will do!


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## mrjayviper

thoughts of replacing JRC 5532 in a DAC output with something else that's easily available? if yes, what would you recommend. nothing too exotic. Thanks


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## Ghoostknight

mrjayviper said:


> thoughts of replacing JRC 5532 in a DAC output with something else that's easily available? if yes, what would you recommend. nothing too exotic. Thanks


probably the best/most individual way of doing this is reading the described sound signatures and pick one you may like from the description

OPA1656/OPA627/OPA1612/OPA1692 (OPA828 would be a upgraded OPA627 which i still need to try out) would be my picks in this order if we are speaking chip-opamps

tho i was surprised how good the 5532 sounded that came as the default opamp in my aune x8 (but it also has some weaknesses, i was specially surprised about the topend (but it can be annoying) if i remember right)


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## mrjayviper

I think I may have enough OPA627BP to make 6 pairs. I just need to look for them.


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## Lobarkaine (Tuesday at 12:22 PM)

mrjayviper said:


> thoughts of replacing JRC 5532 in a DAC output with something else that's easily available? if yes, what would you recommend. nothing too exotic. Thanks


If you are looking for something not exotic you may try the TI NE5532P or the Philips NE5532N or take a look at the  LM4562NA/LME49720NA/LME49860NA as a straight 5532 replacement.
If it may help you I have done a comparative test you may found at this link:

https://www.head-fi.org/threads/dual-op-amps-audio-test-on-dap-and-usb-dac.966422/


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## zachgraz (Yesterday at 2:09 PM)

An update from me.
I have settled on 4x OPA1656 in my Burson headphone amp and 4x OPA1655 in my Ayon DAC. The OPA1655 is the single channel version of the OPA1656.
Amazing value and no more urge to upgrade. In my case the OPA828 has been a clear upgrade to the OPA627 but the OPA1656 is an upgrade to the OPA828.
I used 4 Burson V6 Vivid in my Burson headphone amp but I have replaced them all with OPA1656. Same resolution but simply more drive.
The Burson V6 Classic and V6 Vivid single neither did the trick in my Ayon DAC. The OPA1655s are amazing!
I am selling off my OPA828s 4x single and 2x in dual configuration if anyone is interested (EU).


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## Ghoostknight

zachgraz said:


> An update from me.
> I have settled on 4x OPA1656 in my Burson headphone amp and 4x OPA1655 in my Ayon DAC. The OPA1655 is the single channel version of the OPA1656.
> Amazing value and no more urge to upgrade. In my case the OPA828 has been a clear upgrade to the OPA627 but the OPA1656 is an upgrade to the OPA828.
> I used 4 Burson V6 Vivid in my Burson headphone amp but I have replaced them all with OPA1656. Same resolution but simply more drive.
> ...


oh kinda surprises me you exchanged V6 Vivids with the OPA1656, while i also think the OPA1656 is a very good chip opamp (actually the best chip opamp i heared), i think the V6 Vivid is a somewhat clear upgrade, atleast for the most part

the one/two things i noticed with the OPA1656 is it has really good (but maybe overemphasized) bass and probably the least sibilance at all but the V6 Vivid shines at other things (mostly "overall" i would easly describe it) i really like old records with the V6 for example  and with the OPA1656 i was mostly listening to new stuff

How much you want for a 828 dual (shipped to germany)? while i dont have the urge to try it i still miss it in my collection


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