# Best sounding cheep op-amp for CMoy's? OPA2227, OPA2228, AD8066...other?



## Joshatdot

I am going to order atleast 12 op-amps for my CMoy PCB boards, and looking for best general sounding op-amp for the CMoy. I know the 8066 will need a BrownDog adapter..I wish it was offered in 8-DIP =\


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## balou

AD823 has a bit more limited soundstage, and the highs are not as prominent as in the ad8066. it also consumes less power. for a portable cmoy, I'm tending to recommend the AD823. if cars are driving past you in 2m distance, you won't hear that piano player in 3m distance. I seem also to be more distracted by pronounced highs while on the go. for a home cmoy, ad8066 will likely be the better choice

 but I haven't yet heard opa2227/2228. 2228 will likely not be an option for me, because it needs a gain of least 5 to be stable (I want gain 3 for my grados), and it's availability is limited. but an opa2227 should be on the way to me.

 the bb/ad decision seems to depend on taste and on headphones used - I'd recommend you to buy from both companys, to get to know to their 'house sound'


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## Joshatdot

Quote:


  Originally Posted by *balou* /img/forum/go_quote.gif 
_~snip~
 the bb/ad decision seems to depend on taste and on headphones used - I'd recommend you to buy from both companys, to get to know to their 'house sound'_

 

Yeah I would go half OPA2227 & half AD8066, but I would need the adapters which doubles the price =\


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## fortney

Before you order all the different op/amps you might want to do a search here and on Headwize re A/B comparisons of the sound of amps that are the same in all respects except for the op/amp chosen.

 Someone offered a circuit for a push button A/B changeover and CMoy's library has one using a toggle switch.

 F


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## majkel

OPA2227... cough, cough, puke... 
 TLE2142 is MUCH better if you like this kind of sound presentation. AD8066 is very nice, too. OPA2228 is worth making it stable. The gain might be a bit below 5 and will work well.


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## balou

joshatdot, you could diy adapters, see here: http://www.headphoneamp.co.kr/ftp/si.../Tip/SMD-4.jpg

 yup, browndogs are expensive as hell... first you think 'only 3$ per piece'.. but you have to order alot of them.

 I recently got on a opamp buying spree... I already have or will receive:
 NE5532
 LM6172
 LM4562
 OPA2107
 OPA2604
 OPA2227
 OPA2132
 NJM4556
 AD8066
 AD823
 AD843
 AD744
 AD8620
 RC4558

 now I just have to order parts for my pimeta (board has already arrived) and compare them & write a review here 
	

	
	
		
		

		
			





 fortney: considering opamps, I think a long time listening test is more suitable. I must say, short-time a/b-ing seems inferior to me. well, except if it's a very clear difference between two opamps

 majkel: you seem to have a non-standard opamp liking. would you care to explain which opamps you like and why?
 Filburt also seems to have a quite different oppinion about popular opamps, would be nice if he'd posted in here too


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## Zigis

few days ago I build 4 CMoys. I solder all parts on my boards, put OPA2134s from one order in sockets, measure DC ofsets as allways. In different amps different channels 3-8 mV as allweys. Only in one amp right channel are 0.2 mv, left -0 mV. Then I start to listen to all amps. All amps sound normal, but this with low ofsets - 2x more bass and clarity. I change opamp in socket and amp start to sound as allways. Then I marc opamp SUPER and put in my treasure box.
 All 5 opamps are from same order, same wrapping.
 Zigis.


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## majkel

My favourite is AD825, it is single, stable starting from G=1, and 50mA capable. Great soundstage, no veil, very musical, impactful, no harshness, colorful but not colored sound. There is nothing better IMHO. I suggested one guy to use them, and he discarded from his amplifier 2x OPA627 for those AD825s. Another happy guy! 
	

	
	
		
		

		
		
	


	



 I heard all chips from balou's list except JRC4558 and LM4562. So...
 NE5532 - the only good is from Signetics, all others suck
 LM6172 - very nice, impactful, clean, dark, some people find it cold
 OPA2107 - dark and laid back sound, very deep soundstage, not so broad
 OPA2604 - a bit like a tube, rolled off on both ends, a bit boring and too rounded for me
 OPA2227 - terribly laid back, bass heavy, veiled and slow. Completely not my type
 OPA2132 - almost like OPA2134, maybe a bit smoother sound. Generally - tubby bass, mediocre soundstage, recessed subbands of the midrange and not very detailed treble. Nothing special.
 NJM4556 - sounds... funny 
	

	
	
		
		

		
		
	


	




 Nice sound but I don't know why it sounds funny to me. Smooth sounds with long decay, no harshness. I haven't listened to this one for prolonged time.
 AD8066 - good soundstage, a bit narrow, big bass, veiled midrange, nice treble and overall caramel sound signature. I like it
 AD823 - a bit harsh making it perceived as detailed, but it is not very detailed. Weak impact in sound, rather analytical. One of the noisiest I know. I don't remember all details well because I found better chips later soon.
 AD843 - impactful and harsh, sometimes it's getting unpleasant. IMHO tangensoft overrated it saying it's around OPA637's class. It is not. Too unnatural.
 AD744 - very natural in color and soundstage which might give impression as present everywhere. What I dislike is its relaxed and therefore "dead" sound. However some people may like it.
 AD8620 - good impact with quick and punchy bass, very good soundstage, not spectacular though, slightly harsh and slightly veiled - kind of a nonsense tradeoff. Some people find its highs too aggressive, I don't. 
 Other tested...
 OP275 - like V-shaped equalization curve, bass up, treble up, recessed mids, overally good and just nothing special, simply good, maybe very good.
 OPA2228 - uncompensated alter ego of OPA2227 but totally different. deeper but not muddy like 2227's bass, actually very nice, lots of air in midrange and silky highs. Warm and natural. Just slightly laid back with delicate veil which pairs well with 2228's airy presentation. Electric guitars and female vocals sound nice and intimate. Very likable chip, but not for low gains. You can compensate its feedback loop with capacitors, but I don't like this method and find it degrading the sound a bit. 
 TLE2082 - many times my favourite but no longer. It's like unveiled, more metallic in treble and less harsh AD8620, better and clearer soundstage, punchy and filled up bass. This chip is more on the bright side.
 TLE2142 - sounds dark, with well detailed highs, strong and precisely articulated bass but not as filled with mass as AD8066. You may find the midrange a bit loosing color, but soundstage and its deepness is ver good.
 AD797 - is like more analytical version of AD825, less impactful and with some glaze over highs. 
 OPA637 - very natural and detailed in the whole spectrum, preserving all music singature besides life. For me this chip is uninvolving. It's good for analysing music, not listening for pleasure.
 AD8397 it is power hungry and truly powerful. 310mA peak makes sense as a true amplifier. However you need efficient ground channel to keep AD8397's pace. It is a bit bright, very close soundstage, almost like being between performers. Short decay, overally gives impression of being transparent but it's a bit on the bright and smooth side. Comparing it to be more efficient than 2x BUF634 gives it overall high rating. You can use AD8397 as a dual buffer because it is unity gain stable. 
 I think, that's all... Is my liking non-standard?


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## NelsonVandal

Majkel, nice list of opamps. It would be nice to know what your impressions are based on. Like, were they used bufferd or not, at what voltage, did you try AD744 comp pin out etc.


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## balou

thanks majkel, an interesting list.
 dunno exactly if your overall liking is non-standard - but your recommendation for the ad825 sure is. the only time I've seen it mentioned was in the jung superregulated power supply. as a better alternative to the ad797, which you interestingly seem to place in the same performance category. 

 about the rc4558: I heard it in a phono preamp. terribly noisy with high gain. [I btw fixed that preamp by replacing the opamp, grounding it properly and removing that dual micro/phono preamp option (yeah, a strange amp...)]. but only costs like 30 cent. I'm gonna use them to practice mounting so8 chips to dip8 sockets with sijosaes bending method. and I'm interested how such an ancient chip will perform. maybe its even better than the opa2132


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## Joshatdot

Quote:


  Originally Posted by *balou* /img/forum/go_quote.gif 
_joshatdot, you could diy adapters, see here: http://www.headphoneamp.co.kr/ftp/si.../Tip/SMD-4.jpg
 ~snip~_

 

Ahh yeah, but I would like the op-amps changeable.


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## colonelkernel8

Josh, just scrap the cmoy, lol. Its time to move on! Hasn't upgraditis set in yet?


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## jcw122

majkel, what is used to let two single channel op amps work in a dual channel setup? Like what adapter would I buy for that?

http://cimarrontechnology.com/index....WPROD&ProdID=9 Is it this?

 Thanks.


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## Joshatdot

Quote:


  Originally Posted by *colonelkernel8* /img/forum/go_quote.gif 
_Josh, just scrap the cmoy, lol. Its time to move on! Hasn't upgraditis set in yet?_

 

They are not for me, they are for gifts & Kits for others here in Head-Fi.


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## jcx

I wouldn't reccomend AD8397 for unity buf use when you want to swing close to the rail V, the input common mode range is much less than the output swing

 either use inverting or gain of +2 or more to prevent input stage limits from causing distortion when the output stage would be quite happy swinging close to the rail


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## Filburt

I didn't find the AD8397's soundstage very narrow, personally; it seems to perform more happily when not using a 'ground channel' in my experience.

 IMO, most op-amps are not really suited for this type of application. If you're running at 6V, use an OPA2365 or AD8397. Up to 12V, you could either try the ADA4899-1 or the OPA656 I guess, though make sure to use the Ib cancellation on the 4899 if you use that. Those are single channel op-amps. If you're more sophisticated, and feeling very adventurous, you could try the AD8099 but it takes more effort to get it stable. It needs external comp (think NP0 SMD cap) to run below gain 15, but will go down to gain 2 with such comp. Would need ample bypassing and a non-standard feedback loop. Fun chip, though, and has an Ib cancellation circuit to get it down to 100nA or so. However, it's not for beginners.

 I thought that AD825 was decent; I guess you could try that *shrug*.

 Also make sure, whatever you use, that you have proper rail bypass so you can get optimal performance. Just because the thing isn't squealing and burning up doesn't mean it won't benefit from implementing proper supply design. For adaptors, I'd use either the ones made by Aries (or something similar), or maybe the ones Per-Anders makes as those would make bypassing easier.


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## Yen

Quote:


  Originally Posted by *Joshatdot* /img/forum/go_quote.gif 
_Ahh yeah, but I would like the op-amps changeable._

 

You can stack those on top of other DIP8-socket == changeable.


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## NelsonVandal

Quote:


  Originally Posted by *Filburt* /img/forum/go_quote.gif 
_I didn't find the AD8397's soundstage very narrow_

 

Dito. The soundstage is one of the best. It's both wide and deep yet accurate (i.e. it sounds narrow when it should, unlike e.g. LM6171/72 and LM4562). It's tremendous more impactful than AD8620, which I found to be lean and bass shy, even in front of a buffer. I've never heard any opamp close to 8397 when it comes to slam, punchy bass and impact. It's major flaw is it's "shouty" - very in your face and demanding.


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## majkel

Some more info... I tested the chips in a Cmoy with tweaked version of AB virtual ground, and also having their single version (lika OPA134PA against OPA2134PA) - as a "my own idea" buffered virtual ground, with AD8397 on the channels side. As I could realize the influence from both sides, I described both.

 Regarding AD8397 - its soundstage is very close, but huge and deep. You feel like you could grab the drummer's stick, being amongst the instruments. It sounds a bit bright and damped, lacking a bit of transparency, however smooth and intimate. I agree with NelsonVandal, it's impact is out of range of any regular op-amp. If you need a true amp for bigger cans, use AD8397 or buffer your op-amps with BUF634s or discrete buffers. Otherwise it does not make much sense beyond IEMs. Im exaggerrating, but follow the idea.


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## majkel

Quote:


  Originally Posted by *jcw122* /img/forum/go_quote.gif 
_majkel, what is used to let two single channel op amps work in a dual channel setup? Like what adapter would I buy for that?

http://cimarrontechnology.com/index....WPROD&ProdID=9 Is it this?

 Thanks._

 

There are some better but I dunno where. 
	

	
	
		
		

		
		
	


	




 You need 2*SO8 to DIP8 op-amp adapter. I saw ready kits including 2*AD825 and 2 small electrolytic caps, with DIP8 pinout. It was an accessory for CD player tweakers.


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## balou

You could etch your own... or a group buy of an olimex-made pcb would also work


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## ericj

If you're exploring cheapie opamps, you may also want to give the jrc2068 a try. A bit more neutral than other jrc/njm parts.


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## fortney

I think it would be worthwhile if the op/amp reviewers would include the name of the headphones they used in their reviews and also the capacitance of the power supply and input capacitors in their CMoys.

 F


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## balou

Joshatdot: I have to revise my recommendation for the AD823. depending on your interpretation of cheap, the AD8066 really might be better. The AD823 is 3.2$ cheap, the ad8066 5.2$-cheap. if you intend to make complete kits, this really is a cost/performance tradeoff. the ad8066 really seems to be clearer, with better separation. but with higher current draw, and it will be more prone to oscillation because of its speed


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## Joshatdot

I think I'll go for half OPA2227 & half AD8066 w/Soldered 8-DIP Socket


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## Joshatdot

One other thing, what would be a good general Gain setting for either 2227 or 8066? Gain 11, Gain 6, other?


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## majkel

For single 9V battery it is stable and comfortable to have gain of 5~6. With two 9V batteries you can go 11 to better satisfy high impedance heaphones (lower impedances don't need much voltage). 
 AD8066 is for sure better than AD823. The latter is harsh and noisy.


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## Joshatdot

my CMoy PCB is built for dual 9v batts, but could be used for a single.


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## Filburt

I don't understand why you would use the OPA2227. Distortion is quite high above a few KHz. It's really designed to be used in DC or low frequency applications. The 8066 is...better I guess, but I still wouldn't recommend it.

 Honestly, I'd say the most cost effective solution is just to use AD8397s for these if you're planning to hand them out to people. It's inexpensive and, really, it isn't particularly difficult to use. Just do proper bypassing and it should be plenty stable. The 8066 and 2227 are far inferior in load driving capability and you're pretty much inviting much higher distortion by using them. I'm not trying to be flippant about it (I'm not upset or anything ), but the choices people make for their CMoys to go with chips like the OPA2227, I think, contributes greatly to the later impression people come to that they'll benefit tremendously from buying a commercial portable amp.


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## NelsonVandal

On the other side, who want's to compete to Mini3, XP-amp or PINT? Better do something unique.


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## majkel

Filburt is right. Some day all DIYers realize that TRUE amplification started on the day they dropped in AD8397 and all before was cheating themselves they had build an amplifier. Cmoy may act as an amplifier when compared to low power mp3players having a couple of miliwatts output, and that's all. And yes, chips working close to their current limits distort significantly. This is the case with all plain audio and non-audio op-amps. Regarding OPA2227 it is not that slow. OPA2277 is intended for precise DC devices but this chip is totally unsuitable for audio IMHO. 
 What I suggest is copy all voltage feedback from low-noise PINT version and use AD8397. As a virtual ground - op-amp + BUF634 or Sijosae AB Virtual Ground with electrolytic caps on output side, no cap divider before transistors! It is wrong and screws up idea of the circuit. Trust an electronic engineer.


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## balou

majkel, is your post about amps in general or just about unbuffered amps?

  Quote:


 As a virtual ground - op-amp + BUF634 or Sijosae AB Virtual Ground with electrolytic caps on output side, no cap divider before transistors! 
 

um, could you explain this? you mean caps between the buffers and the headphone ground?


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## majkel

Quote:


  Originally Posted by *balou* /img/forum/go_quote.gif 
_majkel, is your post about amps in general or just about unbuffered amps?_

 

It was about unbuffered amps. If you have an additional buffer (chip/discrete) you use and enjoy any op-amp, AD8397 being inadequate then. 
  Quote:


 um, could you explain this? you mean caps between the buffers and the headphone ground? 
 

I mean doing it exactly like in sijosae Virtual Ground drawing. Tangentsoft gives discrete Virtual Ground drawing with capacitors on the wrong side. Actually, they both work but sijosae sounds better.


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## balou

The AD8066 sucks... I have to rerip several albums with higher bitrate.
 Nothing but problems with all this audiophile stuff 
	

	
	
		
		

		
		
	


	



 ...



 majkel, I now see what you mean. seems like a mistake by tangent. but I think one big cap rail to rail would be the better solution anyway. maybe coupled with two small rail-to-gnd caps, like in the mini³ v2


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## Filburt

I'd recommend the LMH6321 over the BUF634, personally, if you're planning to use an IC buffer.


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## Joshatdot

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Filburt is right. Some day all DIYers realize that TRUE amplification started on the day they dropped in AD8397 and all before was cheating themselves they had build an amplifier. Cmoy may act as an amplifier when compared to low power mp3players having a couple of miliwatts output, and that's all. And yes, chips working close to their current limits distort significantly. This is the case with all plain audio and non-audio op-amps. Regarding OPA2227 it is not that slow. OPA2277 is intended for precise DC devices but this chip is totally unsuitable for audio IMHO. 
 What I suggest is copy all voltage feedback from low-noise PINT version and use AD8397. As a virtual ground - op-amp + BUF634 or Sijosae AB Virtual Ground with electrolytic caps on output side, no cap divider before transistors! It is wrong and screws up idea of the circuit. Trust an electronic engineer. 
	

	
	
		
		

		
		
	


	


_

 

I am just making the standard CMoy design with a TLE2426 instead of the resistor divider. If I were to totally redesign my PCB for the BUF634 or Sijosae AB virtual ground, there'll be a extra $5 processing charge for the new files processing of the same board we already accepted for manufacturing.


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## Earwax

Sorry for dredging up such an old thread, but I wanted to stick in my 2 cents and vote for the TLE2072 as the best cheap opamp for a 9V cmoy. I must have tried 20 different opamps, and I thought the TLE2072 is best. Try it! 

 Dual OPA627 and the OPA2107 may be better if you have more voltage and more $, but then at that point you're probably moving on to some other design anyhow.


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## onesandzeros

Quote:


  Originally Posted by *Earwax* /img/forum/go_quote.gif 
_Sorry for dredging up such an old thread, but I wanted to stick in my 2 cents and vote for the TLE2072 as the best cheap opamp for a 9V cmoy. I must have tried 20 different opamps, and I thought the TLE2072 is best. Try it! 

 Dual OPA627 and the OPA2107 may be better if you have more voltage and more $, but then at that point you're probably moving on to some other design anyhow._

 

I'm glad you did dredge it up, I was looking for this sort of info a few months ago when I built a cmoy... Good discussion.


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## simssmo

Hi I'm new to the site, I bought a cmoy from ebay and wanted to upgrade the opamp

 From what I've read so far AD825 is the best opamp, however, will it work in my cmoy.

 It currently has an OPA2134PA on a DIP-8 IC socket.

 I've visited this site http://www.analog.com/en/amplifiers-and-comparators/operational-amplifiers-op-amps/AD825/products/product.html but I'm not sure which 8 pin one to get.

 Any advice is welcome, also does anyone know where to get these opamps from as I live in the U.K.


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## gurusan

They have it at farnell ANALOG DEVICES | AD825ARZ | Amplifiers & Comparators | Semiconductors - Integrated Circuits | Farnell UK

 but you will need a browndog adapter


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## simssmo

thanks gurusan


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## marksk

Quote:


  Originally Posted by *Earwax* /img/forum/go_quote.gif 
_Sorry for dredging up such an old thread, but I wanted to stick in my 2 cents and vote for the TLE2072 as the best cheap opamp for a 9V cmoy. I must have tried 20 different opamps, and I thought the TLE2072 is best. Try it!_

 

can i use tangentsoft's schematic or do i need to use a different one for the 2072?


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## cobaltmute

It is dual so you can use it in Tangents tutorial


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## joms

Hi guys, what opamp would you recommend me to put in my sub output? I will use it on the addon card of my Asus Xonar Essence.
   
  Asus Xonar Essence ST = 2x OPA2137P + 1xLME48720NA
  Asus Xonar H6 Addon card (sub out) = ???
   
  For Computer setup:
  My front speaker = audioengine 2
  My subs = Velodyne Impact 12


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## FallenAngel

Uhm... I always thought the 137 was a terrible opamp, you're using it or it came stock?
  I generally like the AD825


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## majkel

OPA2137 is great when stable. I had problems with the OPA2137 in one of my headphone amps so I left it alone. But when stable, I like it very much. It's pretty confusing that such a slow op-amp produces artifacts, i.e. on piano notes being obvious it's instability. AD8066 is interesting for bass alone. Otherwise, you can use the AD8599 for instance.


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## digger945

Quote: 





balou said:


> joshatdot, you could diy adapters, see here: http://www.headphoneamp.co.kr/ftp/si.../Tip/SMD-4.jpg
> 
> yup, browndogs are expensive as hell... first you think 'only 3$ per piece'.. but you have to order alot of them.
> 
> ...


 

 I have some RC4558s. The JRC4558 is used in my NAD 1130 preamp, which was one of my very first headphone amps. I still really like listening to it, and it's fun to play around with the bass and treble. I think nikongod uses JRC4556s in his balanced cmoy.


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## HAWK1111

I see that your post is years old, however I am having a cmoy amp built and wanted to know if the AD825 is still the best chip to use. I like punchy, hard hitting bass, very detailed mids & highs. Great soundstage. I listen to mostly hard rock. Looking at your detailed  reviews of all those chips, I am undecided on the following chips; AD8066, AD8620, TLE2082, TLE2142, AD8397, or AD825
  I am very new to this and would appreciate your advice. I am not sure if this would affect your recommendation, but I will be using Koss Portapro headphones with the following specs; 15-25,000Hz, Impedance 60 ohms, sensitivity 101 dB SPL
   
  Thank You


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## ElephantAudio

Any thoughts on the OPA 2111 Dual Low Noise Precision Difet Operational Amplifier audio chip? OPA2111
 It is suggested as better than NE5532. I'm not a technician at all and wish to know if can be use on cMoy v2.03?


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## stv014

Quote: 





elephantaudio said:


> Any thoughts on the OPA 2111 Dual Low Noise Precision Difet Operational Amplifier audio chip? OPA2111
> It is suggested as better than NE5532.


 
   
  Not really, it is noisier, has much lower GBWP, and much higher open loop output impedance. It is probably not great for driving a low impedance headphone load.
  If you can get the NJM4556, I would recommend it, using the lowest gain that is sufficient; it can output up to 100 mA current, drives low impedance loads well, is stable (no output resistor is needed), and costs less than $1.


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## Tommy Thong

i tried with LM4562Na, sounds perfect on high and details, tight-bass


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## guanglier

Hi guys !
   
  I'm really surprised to see your replies concerning the op amps !!
   
  could someone describe the setup ?
   signal source (with THD)
   headphone used
   impedance and THD of the headphone.
   
   
  why ?
  because i see that this op amp is bad, this one is marvelous... am i the only one to find this wierd ?
   
  example : it has been said that OPA2227 is aweful... but !  with 3nv/SHz this is an awesome performance ! moreover channel separation is 138dB ! but the main thing is the THD (total harmonic distortion), at 1Khz it's 0.00005 % !!!!!!!!!!!!  (3.5V rms) how could you ear that ?
   
  So why this marvelous op amp isn't able to drive correctly headphones ? maybe the problem is not the OP amp !!
   
  have a look at impedance of the headphone vs frequency, its wery non linear. considering the fact that these op cannot supply so much current, there are frequencies where sound is well amplified and many other frequencies where it is not. Example : sennheiser HD650, 300ohms at 10hz, 490 ohms at 100hz, 310 ohms at 2khz ... so the point is : non linear load, weak op amp -> uncertain results.
   
  That's why the sound is so different from differents op amp : each smal technical characteristic is amplified by the difficulties for the op amp to drive. In electronic it's a way for disaster.
   
  my conclusion : the CMoy is a bad amp, the op amp is not a concern.
   
  a final power stage is needed for the headphone amp to work correctly. Think about headphones with 45 ohm impedance, what's the difference wetween your sound card and this weak amp ? this poor op amp cannot supply the 45 ohms headphones ! ! that's not a power amp !
   
  one good headphone final stage can be found here (this is NOT my schematic)
  http://electroschematics.com/wp-content/uploads/2009/06/hifi-headphone-amplifier.gif
   
  in this case, the op amp compensates for the conduction gap of the transistors, and ensure minimum THD when transistors ensure power. to improve you need condensators in  // with diodes, but that's another topic.
   
  I'm open to discuss more.


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## james tayao

Hi everyone... I'm new here and also to headphone amps... I was able to try the JRC 4565 yesterday (these came from an old Creative Viba sound card)... not yet fully tested... but is working using sine waves... will try them today using different loads and different frequency...
   
  also I came upon another opamp the M5216 (from a creative SB 5.1 live sound card)... data sheet indicates it's best for portable headphone amps they have curves for 32ohm loads... has anyone tried them?


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## guanglier

hi,
  can't find the part "m5216" or "NJM5216", is the ref correct ?
   
  Anyway the opamp like JRC 4565 is just an opamp, not a poweramp !
   
  what is the impedance of your headphones ?


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## james tayao

guanglier said:


> hi,
> can't find the part "m5216" or "NJM5216", is the ref correct ?
> 
> Anyway the opamp like JRC 4565 is just an opamp, not a poweramp !
> ...




Yes, m5216 is correct, i just googled it and found the datasheet somewhere.. its made by panasonic. 
I got it to work now using a different circuit
.. cmoy circuit does not work well for me.. 
I'm am using a 32 ohm TDK HP.


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## guanglier

the cmoy is not a good amp. That's my point of view.


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## Synthax

Which one do you can advise for CMoy bb 9V to got: very wide soundstage, analog deep bass, and not as exposed heights as with OPA2227


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## guanglier

the OPA 2227 THD is 0.00005% !!!!!
  could you ear the distortions of the bass ??


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## Magicman74

My favorite Duals
  LM4562   LT1364


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## Synthax

Well, maybe it is not a metter of bass perception, but I hope you agree that the op-amps change the sound characteristic.


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## guanglier

hi
   
  yes it changes beause it is not well used !
  these types of OP amp are not designed to directly drive these loads, that's why the sound changes between amps .
   
  you can't possibly use a led driver to drive a motor... here there is no power stage,
   
  here is a good output stage  (see Q1 and Q2)


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## guanglier

here is the amp i designed, i measured with scope and function generator, signal is perfect even at 100 Khz !


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## thedtecter

Looking for forum advice on what opamp will provide the cleanest bass. This is not for audio listening but rather to use with some field equipment. Units are coupled with Bose QC-15's set on low, believe impedance is rated at 73 ohms +/- 10% at 1khz. My needs are quite low end - top end is < 5000 hz and I need very clean, smooth sound < 1500 hz. Would consider 2x 9v as power supply in the cMoy if that offers better chip options. Thanks!


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## NuClear235

What is the best setup of out optimized for Sennheiser HD800 with 300 ohms?
I want to make DIY portable headphone amp (2x9V accu) for HD800...


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## tomb

nuclear235 said:


> What is the best setup of out optimized for Sennheiser HD800 with 300 ohms?
> I want to make DIY portable headphone amp (2x9V accu) for HD800...


 

 For a $1500 pair of headphones, maybe you should consider something more than an opamp and a couple of 9V batteries.  More than that, are you seriously considering using the HD800 as a portable?


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## NuClear235

It is true... 
But I have DIY headphone desktop amp and it sounds not bad. It is not optimized for high ipedance headphones. So I just want know how it should be made. I want make in future portable amp for my HD800. Yes, I can buy it, but is time to make some thing by my hands  I like it.


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## guanglier

I totally agree with tomb
  
 What's the point of having a $1500 headphone with a simple opamp and a 9v battery ?
  
 CMoy and so on... i respect the believe, but from an electronic standpoint, it's not what you're looking for.
 For such a headphone, you should consider, at least :
  
 bandwidth, floor noise, intermodulation distortion, dynamics, precision, distortion, phase shift
  
 I have a HP3577A (network analyzer 5Hz-200 Mhz) and it's surprising what i can see from so called "marvelous" amps...
  
 By the way, don't tell me you'll be listening music on the road  ! ! !


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## NuClear235

It was just idea DIY some device. I can buy profi gear od course, but I like do some small thing myself. 
Best will be for example Cypher Labs Duet.
Is portable, balanced, with good sound....
I want to be "portable" in complete auidio chain. I have AK 100, headphones... so last thing is amp. On some places I need hear music and move myself! It is not real traveling it is mobility. And in the night, when I listening the most, is horrible to have in bed player, headphones and then wire to desk where is amp and second wire from desk to headphones in bed. So with portable amp it will be all in bed.
I have now do-it desktop amp (it made my friend). Inside is NE5534 and it sounds not bad. Maybe is now better OPA. So I am reading this thread to learn more.


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## CADCAM

I have found the TLE2082 sounds best with my biosciencegeek CMoy. Nice detail for the price.


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## Bassman999

cadcam said:


> I have found the TLE2082 sounds best with my biosciencegeek CMoy. Nice detail for the price.


 
 I am probably getting a biosciencegeek cMoy.
 He has 4 choices of opamps
 AD712
 OPA2227
 TLE2082
 JRC4556
  
 Or is there other opamps that work with his cMoy?
 I havent decided what battery setup yet, as he offers single 9v, dual 9v either series or parallel.
 Right now since I am new to headphones for the most part I am starting off cheap.
 I am getting Ha-S500s  and HD668Bs
 Ill see where they take me.
 I have taken home audio to the extent that my wife hates speakers now lol.
  
 Anyway if there is a better drop in opamp not on his list like the 8397 (read positive about earlier in this thread) regardless of price without needed circuit reworking, but will fit within the battery options available please tell me.
 Thanx
 Bassman


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## CADCAM

bassman999 said:


> I am probably getting a biosciencegeek cMoy.
> He has 4 choices of opamps
> AD712
> OPA2227
> ...


 
 I tried several different op-amps with my bio-cmoy but felt the TLE2082 was the best sounding op-amp for me. It has a lively, clean, detailed sound with great highs and lows while not forgetting about the mid-range. I actually messaged the seller\designer of the amp to tell him to try the TLE2082 in his amp and once he did he added it to the list of available op-amps. I believe he uses it himself in his own amp. I never powered mine off batteries and only used a quality adaptor so I can't give any advise there.
  
 I also have the HD668b headphone and really like it, it was my first real headphone and I haven't felt like selling it yet! I did put some soft velours on them though.


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## Bassman999

cadcam said:


> I tried several different op-amps with my bio-cmoy but felt the TLE2082 was the best sounding op-amp for me. It has a lively, clean, detailed sound with great highs and lows while not forgetting about the mid-range. I actually messaged the seller\designer of the amp to tell him to try the TLE2082 in his amp and once he did he added it to the list of available op-amps. I believe he uses it himself in his own amp. I never powered mine off batteries and only used a quality adapter so I can't give any advise there.
> 
> I also have the HD668b headphone and really like it, it was my first real headphone and I haven't felt like selling it yet! I did put some soft velours on them though.


 
 Tele2802 huh ok.
 Ill buy one.
  
 Is there an opamp that costs more that would be better, or are they all just $2-$5?
  
 Have you seen the recent raise in price for the Superlux?
 They went from like$36 to $57 and up.
 As a matter of fact Amazon has raised the price by 2-3$ every day for the last week or so...


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## CADCAM

bassman999 said:


> Tele2802 huh ok.
> Ill buy one.
> 
> Is there an opamp that costs more that would be better, or are they all just $2-$5?
> ...


 
 Yea... Amazon looks to be out of them and the price is up, good thing we already have them
	

	
	
		
		

		
			




  
 The op-amp is a TLE*2082, *I purchased mine at Digi-Key and they are inexpensive. I still use my cmoy connect to a LCD TV in my bedroom running a pair of Koss Ports Pro's... sounds great to me for the TV.


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## Bassman999

cadcam said:


> Yea... Amazon looks to be out of them and the price is up, good thing we already have them
> 
> 
> 
> ...


 
 I didnt buy the Superlux yet, they were in my cart for over a week lol.
 I went to check out over the weekend and they were removed for lack of stock from that seller.
 Do you think they will go down in price again?
  
 I might just buy something else if they stay that high..
  
 I did get the HA-S500s though.


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## musubi1000

I wish I could cross breed an s500 and a 668. The lows on the S500 together with the openness and highs of the 668 would be a great combo.


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## Bassman999

musubi1000 said:


> I wish I could cross breed an s500 and a 668. The lows on the S500 together with the openness and highs of the 668 would be a great combo.


 
 Yeah the JVC S500 has no depth to it, and feels all in my head.
 I find it slightly claustrophobic really, except for rap and R&B
  
 I am shopping for phones for an open sound for jazz etc...


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## Th3l4st0ne

If you can build a circuit able to support it, the LM6172 is one of the best I ever heard. But then, for a portable amp, it's going to eat trough batteries like an Head-Fier goes through headphone.


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## Bassman999

th3l4st0ne said:


> If you can build a circuit able to support it, the LM6172 is one of the best I ever heard. But then, for a portable amp, it's going to eat trough batteries like an Head-Fier goes through headphone.


 
 does that mean its a more powerful chip, or just uses more?


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## Th3l4st0ne

bassman999 said:


> does that mean its a more powerful chip, or just uses more?


 
 It runs at a higher voltage and is picky about the circuit: you can't dump it in a cheap Cmoy and hope it sound well. It does seems to have a bit more gain, but that may be a side effect of the 30v I'm dumping in it.


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## Bassman999

th3l4st0ne said:


> It runs at a higher voltage and is picky about the circuit: you can't dump it in a cheap Cmoy and hope it sound well. It does seems to have a bit more gain, but that may be a side effect of the 30v I'm dumping in it.


 
 30 V is A LOT lol...much more headroom


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## Th3l4st0ne

bassman999 said:


> 30 V is A LOT lol...much more headroom


 
 Yea, it's a high-bandwidth chip, the main reason it's so picky. But I think it can run decently on 18-20v, check the spec sheet it should be writen there. Otherwise I had OPA2132, AD825 and one of those jellybean chips, the 2132 sounded great at 16-18v, but the LM is just stellar when the layout works.


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## Bassman999

th3l4st0ne said:


> Yea, it's a high-bandwidth chip, the main reason it's so picky. But I think it can run decently on 18-20v, check the spec sheet it should be writen there. Otherwise I had OPA2132, AD825 and one of those jellybean chips, the 2132 sounded great at 16-18v, but the LM is just stellar when the layout works.


 
 Could I take my cMoyBB 2.02 and just series an extra 9v batt in there to run the 2132?


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## bootdsc

Just drop in a jrc4556 and run off any voltage battery using a step up/down voltage converter set to what ever voltage you like(i run mine at 10v)


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## Bassman999

bootdsc said:


> Just drop in a jrc4556 and run off any voltage battery using a step up/down voltage converter set to what ever voltage you like(i run mine at 10v)


 
 Mine came with OPA2227P
 Without comparing it to others I think it sounds decent.
  
 Where do I get a step-up that fits inside this lil case?


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## bootdsc

Polulu is where i get em, i have used quite a few in loads of projects. You want one with a vary high switching frequency so you don't have any audible noise bleed through the ground channel. 
 Here is a link to the one i have used the most http://www.pololu.com/product/2120 this is limited to 12v but they have other models that are made for higher voltage output. If 12v is enough here is a version with a fixed output thats half the price http://www.pololu.com/product/2117


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## Bassman999

bootdsc said:


> Polulu is where i get em, i have used quite a few in loads of projects. You want one with a vary high switching frequency so you don't have any audible noise bleed through the ground channel.
> Here is a link to the one i have used the most http://www.pololu.com/product/2120 this is limited to 12v but they have other models that are made for higher voltage output. If 12v is enough here is a version with a fixed output thats half the price http://www.pololu.com/product/2117


 
 Ok I have a few questions.
 How does this wire into the main board?
 Can I still use external psu with this step in there?
  
 Thanks for the links!


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## Bassman999

bassman999 said:


> Ok I have a few questions.
> How does this wire into the main board?
> Can I still use external psu with this step in there?
> 
> Thanks for the links!


 
 I just got an answer to the 2nd question by reading the specs , that input V cannot exceed output V for fixed value, but can be for the variable ones.


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## Bassman999

Last question is how much voltage can the rest of the cMoy circuitry handle if I switch the opamp and use a step-up?


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## Bassman999

th3l4st0ne said:


> Yea, it's a high-bandwidth chip, the main reason it's so picky. But I think it can run decently on 18-20v, check the spec sheet it should be writen there. Otherwise I had OPA2132, AD825 and one of those jellybean chips, the 2132 sounded great at 16-18v, but the LM is just stellar when the layout works.


 
 Does the higher V circuitry and opamp benefit the higher impedance cans?
 I have a pair of 600 ohm 990s


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## bootdsc

Well i only use batteries with cmoy's because the power supply will add a lot of noise unless its filtered but then you are getting way to complicated for a simple cheap cmoy type amp. Maybe i left out a key detail, i use a 3.7v lipo with the step up converter and a li po charger with all of the portable amps i have built. Depending how much space i have and if the battery can be easily removed ill ether use a usb lipo charger or external charger. I could never understand why people are willing to pay for disposable batteries especially 9v's having such a low ma rating.


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## bootdsc

bassman999 said:


> Does the higher V circuitry and opamp benefit the higher impedance cans?
> I have a pair of 600 ohm 990s


 
 Sure does, use this calculator. Put in the ohm rating and play with the voltage to get an idea of the max amperage physically possible at any given voltage, oh and remember each rail can only sink half the voltage so cut your V source in half(best case scenario if using rail to rail op amp) . Now that you know the max amp's you can pull check the sensitivity of your headphones to figure out how much amperage you need in order to driver them loud enough for your liking. Please forgive any errors in my statements as i'm not a expert but just a hobby enthusiast.


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## bootdsc

bassman999 said:


> Last question is how much voltage can the rest of the cMoy circuitry handle if I switch the opamp and use a step-up?


 
 Missed this one, to be safe you should use capacitors rated double that of the power supply voltage but for a cmoy you can get right up to the cap voltage long as you don't go over. For instance i use 10v caps because of the much smaller physical size and run my cmoy's at 9.05v. But don't listen to me, its not the proper use of caps.


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## Bassman999

I have never heard of LIPO chargers, but I am looking that up as soon as I type this.


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## Bassman999

bootdsc said:


> Missed this one, to be safe you should use capacitors rated double that of the power supply voltage but for a cmoy you can get right up to the cap voltage long as you don't go over. For instance i use 10v caps because of the much smaller physical size and run my cmoy's at 9.05v. But don't listen to me, its not the proper use of caps.


 
 Ok so the weak link in my cMoy and its ability to have a higher rail voltage will be the caps...
 Ill look in there and see what its comprised of, and if I can mod this thing.
 I cant do a from scratch one I dont think based on my poor vision.


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## Bassman999

bootdsc said:


> Well i only use batteries with cmoy's because the power supply will add a lot of noise unless its filtered but then you are getting way to complicated for a simple cheap cmoy type amp. Maybe i left out a key detail, i use a 3.7v lipo with the step up converter and a li po charger with all of the portable amps i have built. Depending how much space i have and if the battery can be easily removed ill ether use a usb lipo charger or external charger. I could never understand why people are willing to pay for disposable batteries especially 9v's having such a low ma rating.


 
 do you use a high capacity 3.7v LIPO batter like 1200 or 4400 mAH or small like 500mAH
  
 I saw this charger..
	

	
	
		
		

		
			




 Simple and cheap


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## bootdsc

I have them in a bunch of capacity's, it really just depends how much space i have but this probably gets the most usage 
http://www.amazon.com/Trust-TrustFire-Protected-Rechargeable-Batteriesed/dp/B005X4SG7W/ref=pd_sim_e_5?ie=UTF8&refRID=1CR3B248EEDDF53NX25A
  
 For longer battery life ill use the 2400ma version but it's kind of bulky and doesn't fit most cases
http://www.amazon.com/TrustFire-Protected-2400mAh-Rechargeable-Batteries/dp/B00ABE7WB0/ref=pd_sim_e_5?ie=UTF8&refRID=1AZG23FCFBZCGWZ4ZC0J
  
 Amazon is not the cheapest place to buy them but its the quickest place to find. Make sure what ever you get has protection circuit built in. 
  
 There is one problem with using lipo's like this, the dc dc converter will keep running and drain the battery well past its safe limits and i have killed one or two batteries this way. You can tell when the battery is getting low because the step up converter starts acting weird and you will hear the distortion. My advise is to just remember to recharge long before the battery fully drains. with 900ma and the 80% efficient dc converter and depending if you run the cmoybb v2 in class A i get about 15 to 30 hours of play time so other then leaving it on over night it feels like i never have to recharge them. BTW the 900ma battery (with protection circuit that adds a few mm length) will fit in a AA battery holder.
  
 Oh and the power switch needs to go between the batt+ and anything else. Depending on the charger board they sometimes slowly drain the battery if its left plugged in so its a good place for the switch.


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## Bassman999

I grabbed the 900mAH with protection and a charger.
 I am going to go with the adjustable step up that goes to 25v, since the caps are all 40v and 50v rated


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## bootdsc

That might not work, there is a limit to how high a voltage you can get based on the input voltage and the type of IC used on the board. it might not go all the way to 24v with only 3.7v input but you'll get at least a high enough voltage to be useful.
  
 The max voltage you can use is based on the max input of the tle 2426 rail spliter. OP-AMP you choose, Capacitors and you will need to change the resistor thats in line with the led or the led will burn out. I could give you all the numbers but wheres the fun in that. You really only need to run at 18v, i don't think there is any benefit going higher.


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## Bassman999

bootdsc said:


> That might not work, there is a limit to how high a voltage you can get based on the input voltage and the type of IC used on the board. it might not go all the way to 24v with only 3.7v input but you'll get at least a high enough voltage to be useful.
> 
> The max voltage you can use is based on the max input of the tle 2426 rail spliter. OP-AMP you choose, Capacitors and you will need to change the resistor thats in line with the led or the led will burn out. I could give you all the numbers but wheres the fun in that. You really only need to run at 18v, i don't think there is any benefit going higher.


 
 I dint think I would go that high anyway, but the choice was up to 12V or up to 25V for the step ups.
 Although even at 12-18V I could use a few 3.7V in series for higher Voltage.


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## bootdsc

bassman999 said:


> I dint think I would go that high anyway, but the choice was up to 12V or up to 25V for the step ups.
> Although even at 12-18V I could use a few 3.7V in series for higher Voltage.


 
 Don't put them in series, you have to use a special battery protection circuit made for using multiple cells. In fact you cant safely use that type of battery in series or parallel. Has to do with the built in protection circuit not being able to handle the higher voltage or something.


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## NuClear235

I will use LiIon accus.
 http://www.amazon.de/Lithium-Ionen-14500-Protection-accu-seidel/dp/B005VFP9RI
 They have thermal, short circuit and undervoltage deep discharge protection.
  
 2x3 cells = 6 x 4,2V = +- 12,6 V. Charging will thru RC model charger.
  
 Here is project with external charger adapter:
 http://www.head-fi.org/t/586042/what-i-did-next-with-texas-headamp-chip-a-digital-control-desktop-portable


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## bootdsc

nuclear235 said:


> I will use LiIon accus.
> http://www.amazon.de/Lithium-Ionen-14500-Protection-accu-seidel/dp/B005VFP9RI
> They have thermal, short circuit and undervoltage deep discharge protection.
> 
> ...


 
 That projects circuit has no way of monitoring the voltage of each cell when charging and relying on the batteries built in under voltage protection board is also a really bad idea because if you manage to drain the battery to far the protection board will keep you from recharging.


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## kaiss3r

Hi! I am planning to design my own "Cmoybb v2.03r". But I am a little bit confused which "opamp" should i use. Confuse in a way that in their schematic diagram, the opamp used is "OPA2134P". But when what is written in their Bill of Materials, they used "OPA2227". So which is which?


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## Andymaxwell

Hi All, I hope this isn't too off topic. I've just bought a CMOYbb to partner my X3 and am looking to experiment with differing sound signatures - with the hope of matching the LO of the X3 (I really like it's sound sig). 
  
@walfredokindly suggested a couple of op amps to try in the CMOYbb, namely JRC4556 and AD712 and some other fine forum member suggested the Lm4562. 
  
 However, the AD712 comes in a number of different guises and I can't figure out which one to get. Would someone be able to advise?...
  
 http://uk.rs-online.com/web/p/operational-amplifiers/7096152/
 http://uk.rs-online.com/web/p/operational-amplifiers/0553589/
 http://uk.rs-online.com/web/p/operational-amplifiers/6060121/
  
 P.S. To al lus UK buyers, RS components has both the AD712 and LM4562 the JRC4556 seems to only be available on ebay.
 And another site to try for op amps is  http://uk.farnell.com.
  
 Thank you


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## TheAlpha

andymaxwell said:


> Hi All, I hope this isn't too off topic. I've just bought a CMOYbb to partner my X3 and am looking to experiment with differing sound signatures - with the hope of matching the LO of the X3 (I really like it's sound sig).
> 
> @walfredokindly suggested a couple of op amps to try in the CMOYbb, namely JRC4556 and AD712 and some other fine forum member suggested the Lm4562.
> 
> ...


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## Andymaxwell

thealpha said:


>


 
@TheAlpha  Haha, wicked, love the coincidence!   I've only just received the JRC4556 from Australia and haven't got round to buying the others yet. Really looking forward to listening to it and will let you know my thoughts when I have.
  
 Really appreciate your thoughts on them buddy -so we've just got to get the right one for our own headphones. And the upside is when you change your headphone, you change your amp signiture. Excellent!


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## nofacemonster

Which OP chip has the dark mellow laid back sound with heavy bass....? I love the sound signature of KZ ZS1. I am looking for something similar, something that sounds warm and tube like.


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## bootdsc

nofacemonster said:


> Which OP chip has the dark mellow laid back sound with heavy bass....? I love the sound signature of KZ ZS1. I am looking for something similar, something that sounds warm and tube like.




When you build the cmoy if you increase the capacity of the input and or output capacitors you will change the roll-off and it will give you a warmer sound. If I was home I could tell you exactly the size I use but it's been a while since I built my last one. I have well over a dozen similar amps I have built. Did you buy a kit or scratch built?


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## nofacemonster

bootdsc said:


> When you build the cmoy if you increase the capacity of the input and or output capacitors you will change the roll-off and it will give you a warmer sound. If I was home I could tell you exactly the size I use but it's been a while since I built my last one. I have well over a dozen similar amps I have built. Did you buy a kit or scratch built?



Thank you for replying me. I am sorry for barging in and sounding like a pro but i am not. I just asked because i ordered a cheap XU-09 headphone amp from eBay and it is said the OP amp can be changed to any desired chip. So since i like warmer mellow sound and i thought i'd change the stock chip with a more mellower warmer sound.


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## madnanny2

majkel said:


> Filburt is right. Some day all DIYers realize that TRUE amplification started on the day they dropped in AD8397 and all before was cheating themselves they had build an amplifier. Cmoy may act as an amplifier when compared to low power mp3players having a couple of miliwatts output, and that's all. And yes, chips working close to their current limits distort significantly. This is the case with all plain audio and non-audio op-amps. Regarding OPA2227 it is not that slow. OPA2277 is intended for precise DC devices but this chip is totally unsuitable for audio IMHO.
> What I suggest is copy all voltage feedback from low-noise PINT version and use AD8397. As a virtual ground - op-amp + BUF634 or Sijosae AB Virtual Ground with electrolytic caps on output side, no cap divider before transistors! It is wrong and screws up idea of the circuit. Trust an electronic engineer.


i am using opa2227,it came in my jds labs bb,i like a smooth treble,is there an op amp i could replace this which wasnt bright


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