# New! WNA MKll Head-amp kit.



## PinkFloyd

I had one of my rare (and to date least sensible) Head-Fi moments last night where I thought I'd delete all 4,674 of my posts (don't ask) starting with this thread I managed to wipe out my posts on page 14 and page 1 before retiring to bed for the night.

 The posts are apparantly wiped from the server so I'll have to fill in the "dots" from memory... ah the silly things some people do when they're hot headed.... I'm just glad that I didn't wipe out everything.

 EDIT: ****! appears I actually reached page 2 as well.


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## Alick

I look forward to your review of the finished item Mike. I suspect I'll be building one soon. I've justified it to myself that I can relegate my original WNA to my study/PC room for use with the SR-80s and I can build a new one for use in my main rig with my new HD650s. I must get my X-Can V2 on eBay!

 Looks like the new PCB will still fit nicely into the Hammond with room for a crossfeed. Are you building a complete kit or are you doing your own thing with resistors, capacitors, case and all? If so, what are you using?

 EDIT: Looks like the board is designed for Natai output capacitors? I suppose that you can use flying leads from those component locations if you want to use beefier (and physically larger) ALCAPs?


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## PinkFloyd




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## doobooloo

How can I purchase a kit or PCB from the US? I'm quite interested.


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## PinkFloyd

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## null

Is the WNA easy to put together pinkie?


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## individual6891

Looking good 
	

	
	
		
		

		
		
	


	




 [edit=What case do the boards fit into?]

 Also - are the original PCBs still available?


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## PinkFloyd

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## Magsy

Very nice, with both the pot and jack on board some very neat amps are going to be built 
	

	
	
		
		

		
		
	


	




 Is there a parts list somewhere? (So I can work out the cost)


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## Syzygies

Looks very attractive.

 If the cards were 100 mm wide they'd fit the slots in Hammond cases, like the N16 that the PPA uses nicely. What's the idea with 90 mm wide?

 It looks like one could get 12 hours from a bank of 20 AA cells, would it be crazy to attempt this as a portable amp? I remember people lugging around Kaypro computers and called them portable...


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## 1UP

mmm, MK2....


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## doobooloo

Quote:


 Hi doobooloo contact Dr. White by clicking on the contact link at http://www.wnaudio.com/ You can purchase either the PCB1 or PCB2 or a full kit.... the full kit is £160 but I don't yet know if that includes PCB1 or PCB 2, full details to follow. All I know at the moment is the PCB1 is £30 and the PCB2 is £35 I'll get the full details asap. 
 

Thanks for the details Mike! I'll keep tuned to this thread for more info.

  Quote:


 If the cards were 100 mm wide they'd fit the slots in Hammond cases, like the N16 that the PPA uses nicely. What's the idea with 90 mm wide? 
 

Good point there. I wonder why it's not just a standard Eurocard size like the PPA, it would have been much easier that way for many DIY builders (Hammond, Lansing, etc.)...


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## PinkFloyd

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## PinkFloyd

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## aeriyn

A question: even with the design changes to the LM6171 standard for the WNA board, can it still function with the AD8610 opamps?


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## PinkFloyd

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## PinkFloyd

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## PinkFloyd

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## T-129

The sound! Tell us how it sounds!


 (Pretty nice soldering btw)


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## PinkFloyd

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## 1UP

Looking good!


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## GoRedwings19

I felt that the original WNA was excellent and will be following with interest. I had great fun using the WNA with the rs-1's and found the rs-1's really enjoyable and not bright. The WNA+RS-1's sounded way better than the GSP solo +RS-1's, IMO.


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## palchiu

Dear PinkFloyd,

 Waiting for your WNA MK II review.


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## PinkFloyd

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## Romanee

A smooth and auspicious startup. I wonder what polish premium parts will provide?!


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## PeterR

Good job, Mike. If you allow a comment on your otherwise admirably tidy soldering - it looks like you might want to try a little less solder (and make sure to melt it on what you're soldering, not the tip of the iron). With a good solder joint you can still make out the shape of what's beneath.


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## PinkFloyd

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## StevieDvd

I'll agree with the strength of Pinkfloyds joints as I tried to de-solder some without knowing of the method he used. Several swear words later I managed to remove the component. I did ask Pinkie how he did his soldering so it won't catch me out in future.

 Pinkie soldering is more like artwork


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## PeterR

Quote:


  Originally Posted by *PinkFloyd* 
_ The method I adopt is to bend the pin over flush with the pad and then snip the pin flush at the edge of the pad, this ensures the pin makes contact with the pad thus making a mechanical connection._

 

That's actually a great way to do it if you don't care about desoldering (and if building a proven design, why would you). I still think you might do with a somewhat reduced amount of solder, but maybe it's just the pics not doing your joints justice. Guess I've been raised to fear those solder blobs...


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## PinkFloyd

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## PeterR

Quote:


  Originally Posted by *PinkFloyd* 
_I'll try and get a shot of a better camera Peter so you can see they are not "blobs" but smooth dome shaped joints 
	

	
	
		
		

		
			



_

 

Yes, that would probably make me sleep a lot better 
	

	
	
		
		

		
		
	


	




 Another thing, does the 'full kit' for 160£ include a case?


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## PinkFloyd

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## PinkFloyd

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## KZEE

Quote:


  Originally Posted by *StevieDvd* 
_I'll agree with the strength of Pinkfloyds joints as I tried to de-solder some without knowing of the method he used. Several swear words later I managed to remove the component. I did ask Pinkie how he did his soldering so it won't catch me out in future.

 Pinkie soldering is more like artwork 
	

	
	
		
		

		
		
	


	


_

 

I need a recomendation for a soldering iron wattage for building PC boards and what-not. I've got a big 100 watter that I use for soldering up wires, but I know that will be too much and too big for PC boards.


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## JHouser

Quote:


  Originally Posted by *KZEE* 
_I need a recomendation for a soldering iron wattage for building PC boards and what-not. I've got a big 100 watter that I use for soldering up wires, but I know that will be too much and too big for PC boards._

 

This is the one i picked up after using my lame 25watt Weller pencil type. It's great becuase it has variable heat so if you have a thick lead you can turn it up a bit. Only $35 too! 
http://www.circuitspecialists.com/prod.itml/icOid/7307


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## KZEE

Quote:


  Originally Posted by *JHouser* 
_This is the one i picked up after using my lame 25watt Weller pencil type. It's great becuase it has variable heat so if you have a thick lead you can turn it up a bit. Only $35 too! 
http://www.circuitspecialists.com/prod.itml/icOid/7307_

 

Ah, variable heat - I didn't even know they made such an animal. Thanks for the link, J-man, and I'll be ordering one of those ASAP.


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## Romanee

Has anyone else used the $35 CSI Deluxe Soldering Station that JHouser has recommended?


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## PinkFloyd

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## scott916

Quote:


  Originally Posted by *Romanee* 
_Has anyone else used the $35 CSI Deluxe Soldering Station that JHouser has recommended?_

 

I have the CSI-Station 2 from circuitspecialists. It is basically the same iron, but instead of analog it has digital temperature control. It's a fantastic unit regardless of price. It heats up to 400c in about a minute and holds temperature extremely well. It also gives a temp indicator as it heats up and holds the temp, updated every half second. I can highly recommend it, especially because it can be had so cheaply... I believe under 50 dollars.


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## PinkFloyd

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## KZEE

Quote:


  Originally Posted by *PinkFloyd* 
_This is not a soldering station thread, we are discussing a kit amp here thanks._

 

Well shoot, you need a soldering iron to put together a kit amp don't you? 
 Tell you what, if you're so sensative that it's a problem for you to allow us to make a few short posts in recommendation of a good soldering iron with which to put kit amps together, then I'm sorry to have bothered you.


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## PeterR

Quote:


  Originally Posted by *KZEE* 
_Well shoot, you need a soldering iron to put together a kit amp don't you?_

 

Yes, but that's in no way specific to the WNA kit. There's a lot going on in this forum and it is of advantage to everybody if we try to keep it at least somewhat organized. If you're looking for info about a soldering iron, it's much better to start your own thread (if you don't find the answers you need already in the hundreds of old threads the search function will bring up). That way, people looking for info on the WNA kit won't have to wade through off topic posts like this one, your question will be seen and be able to be answered by a lot more people than just those interested in the WNA kit, and finally it can later be found much more easily by people smart enough to use the search button before posting. Everybody wins, including yourself.


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## 12796

Hi,

 My understanding from David's first attempt with the LM6181 last night is that the LM6171 is not way ahead of the LM6181 but that there is a barely discernible difference which David is rechecking today with a wider selection of music. Bare in mind the circuit has been tweaked extensively for the LM6171 and the LM6181 will take a week to break in if it's at all like the LM6171 which is very slow to reach it's full potential - if the the circuit is tweaked for the LM6181 it might also be a very different story. I will be interested to hear what others think about the LM6181 as David is trying this chip versus the LM6171 in his headamp as a precursor to substituting it into the custom built volume control and phono stage that he has put together for me. I found the only other serious competitor for the LM6171 is the AD825 which sounds more dynamic and rhythmic, a bit less grey and quicker in the mid-range but also a bit brash and not as tight at the frequency extremes. On balance the LM6171 nsounds better but ideally i would like to combine the best characteristics of both. 

 Regards,

 Nick.


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## PinkFloyd

Hi Nick,

 David has indeed been trying the LM6181 and he reckons it's a close run thing and isn't going to commit one way or the other until he's done some serious listening. I'll fire a couple into my WNA and have a good listen also.

 I've tried the OPA 627, AD825, AD811, LM6171, OPA134, AD8610 and AD8065 in the WNA and the only one apart from the LM6171 I liked was the AD8065, I've got a couple of them kicking around somewhere so may have a listen with them on board again. I'll try the LM6181 first and report back on it 
	

	
	
		
		

		
		
	


	




 Mike.


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## 12796

Thanks!

 Ad8065 isn't stable in the WNA phono without major redesign - I suspect it's better than the AD825. The AD825 gave good results in the 2nd and 3rd stages of the phono - only chip to offer advantage over LM6171 in any area, as I described. 

 Nick.


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## 12796

OPA 134 is awful 
	

	
	
		
		

		
			





 opa 627 vastly over rated also. I liked the ad811 but thought the AD825 beat the ad8610 all around


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## Alick

I'm starting to build my Mk2 later this week and I plan to try the LM6181 after I've listened to the standard configuration for a wee while. I'm using the PCB1 configuration which has the pot and headphone jack off-board. Mike built the PCB2 version which has those components PCB mounted. I don't forsee any great difference in build or sound between these two options, but I'll post my impressions here as I go.


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## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_OPA 134 is awful 
	

	
	
		
		

		
		
	


	




 opa 627 vastly over rated also. I liked the ad811 but thought the AD825 beat the ad8610 all around_

 

8065 works a treat in the head-amp 
	

	
	
		
		

		
		
	


	




 Totally agree with you on the OPA134 it sounds chocolatey, syrupy and just plain dark..... orrible. Not keen on the AD8610 but it sure is better than the OPA134. Must give the AD825 another roadtest after the LM6181.


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## 12796

Is anyone using the WNA cascode PSU? If not then what are you using in it's place? Does the headamp circuit use monolithic regs like the LM317? HAs anyone tried bypassing those if it does?

 Nick.


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## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Is anyone using the WNA cascode PSU? If not then what are you using in it's place? Does the headamp circuit use monolithic regs like the LM317? HAs anyone tried bypassing those if it does?

 Nick._

 

Hi Nick,

 Fellow head-fier "Captain" uses the cascode PSU and he reports good things about it maybe he will chip in here (I can't remember what page on the original WNA thread it was on but will have a look). I don't understand what you mean about the LM317 regs? The headphone circuit doesn't employ any regs.

 Mike.

 Edit: Captain's cascode comments start on this page


 Captain's Cascode


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## scott916

I apologize, next time I'll pm.


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## GoRedwings19

Pink>Is it worth it in your opinion to upgrade to the MK 2 version if you already have a MK1? Or would it just be better to upgrade the power supply that came with the WNA?


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## PinkFloyd

Quote:


  Originally Posted by *GoRedwings19* 
_Pink>Is it worth it in your opinion to upgrade to the MK 2 version if you already have a MK1? Or would it just be better to upgrade the power supply that came with the WNA?_

 

MKll is certainly a lot more forgiving of cheap PSU's thanks to the additional decoupling...... does it sound better than MKl? no (not as far as I can tell though my ears haven't been too good of late).......... it's business as usual apart from the added connectivity options and a tad more grunt into low impedance cans.

 You'd probably be better concentrating on the power supply rather than ditching the MKl for a MKll.... then again you could save yourself money and just enjoy the music the MKl makes........ it's up to you I can't advise one way or the other......... I've tried a few PSU's and the difference between a £7 regulated wallwart and a pricey PSU is subtle......... if you want the last ounce of perfection (as small as it is) regardless of cost then go down that route, I tend to listen to the music these days and don't waste my time looking at overpriced interconnects and humongous power supplies.

 The WNA MKl or MKll makes music for me...... I'm content (happy in fact) with what it does........ do I want to over egg my pudding and attempt to make what sounds good sound better? A year ago the answer would have been "yes" and at that time Dr. White pulled out the stops and made it better......... as it stands now the WNA is good enough to satisfy my appetite so I'm happy with the music it makes........ I'll try rolling a few more chips under the bonnet and if any of them bring the goose pimples up on the back of my neck I'll be sure to report here... as it stands (at the moment) I'm more than happy to sit back and "enjoy the music"

 Mike.


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## GoRedwings19

Hmm a toughie. The WNA is a good in my system. But I use Grado headphones which are low impedance and the extra grunt in the low end would be even better. If the WNA mk 2 wasn't released I would be more than happy with the MK1 but unfortunately I am one of those people who like to get the absolute last bit of performance.

 You mentioned extra connectivity? Do you mean more line inputs?

 There is nothing wrong with using high end interconnects with my WNA baby. I am using SPM reference with it!!!!!


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## 12796

Just curious if it used monolithic voltage regs or not - thanks for letting me know. Anyone tried battery power or super regs?


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## 12796

Try the WNA cables - they beat nordost spm reference cables etc at about 10% of the price. Also worth trying is one of his custom mains cables with inbuilt filter. i can just about hear a difference with nordost or kimber (2-3%) but only on my WNA / Tom evans phono stages, I couldnt hear any improvement on my Brinkmann deck, WNA pre or bryston power amps - but the WNA mains cable made a dramatic improvement - say 20% on the phono and 10% on the other components and again is a fraction of the price. Good quality materials and construction with a lab grade filter is about as good as it gets and cost me about £80. The cheapest option starts at £35. Might be a cheap upgrade to the headamp!


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## PinkFloyd

Quote:


  Originally Posted by *GoRedwings19* 
_Hmm a toughie. The WNA is a good in my system. But I use Grado headphones which are low impedance and the extra grunt in the low end would be even better. If the WNA mk 2 wasn't released I would be more than happy with the MK1 but unfortunately I am one of those people who like to get the absolute last bit of performance._

 

Well you've answered your own question...... MKll it is then 

  Quote:


  Originally Posted by *GoRedwings19* 
_You mentioned extra connectivity? Do you mean more line inputs?_

 

Differences:

 "The first version ( type 1 pcb ) is similar to the previous one ( and can also be used as a buffer amplifier ) except the pcb is a little larger; there are now two pairs of output devices per channel to deliver more grunt into low impedance 'phones; the rail splitter is preceded by a capacitance multiplier to make performance less dependent on the quality of the external power supply; the output caps now mount on the pcb; and each channel is now completely independent ( i.e. the amp is dual mono ) so that you can have one power supply per channel. The latest version of the cascode power supply accomodates this because it consists of two independent regulated outputs ( which you connect in series if you need a split rail power supply )." 

 "The second version ( type 2 pcb ) is as for the first except that the pcb is larger again because the volco and headphone jack now mount on the pcb." 

  Quote:


  Originally Posted by *GoRedwings19* 
_There is nothing wrong with using high end interconnects with my WNA baby. I am using SPM reference with it!!!!! 
	

	
	
		
		

		
		
	


	


_

 

Of course there's nothing wrong with it Mike, I just don't believe in paying megabucks for a metre of copper and make my own


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## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Just curious if it used monolithic voltage regs or not - thanks for letting me know. Anyone tried battery power or super regs?_

 

Haven't tried battery power but WNA do supply a battery pack kit for use with the head-amp...... may well give it a go once I'm feeling a bit better.

 I use a calex open frame PSU with the WNA, can't remember what reg it uses but will look next time I'm under the bonnet..... IIRC it's a pretty good reg:





 Uncased





 Cased up

specs


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## gsferrari

Wow!! A wood base chassis...doesnt get any nicer. But why didnt you leave it in the wood color with maybe a light coat of laquer for protection?

 Whatever - it looks stunning and "uber modern" 
	

	
	
		
		

		
		
	


	




 Pinky - how about sending a KIT my way...

 lemme know the price and i'll arrange payment.

 Best regards,

 gs


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## PinkFloyd

Sorry if my posts are not as comprehensive or "enthusiastic" as normal, I've had a couple of months of on and off illness (toothache, cluster headaches, colds, earache etc.) I'm so run down I can barely drag myself to the computer, let alone type, hopefully I'll be back to normal and enthusiastic soon..... it's taking a long time to shake whatever it is off this time 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


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## PinkFloyd

Quote:


  Originally Posted by *gsferrari* 
_Wow!! A wood base chassis...doesnt get any nicer. But why didnt you leave it in the wood color with maybe a light coat of laquer for protection?_

 

You gotta be joking GS? That was a lump of blue painted MDF that was kicking about in the garage and I screwed the psu onto it before the enclosure arrived...... it was only a temporary base 
	

	
	
		
		

		
			





  Quote:


  Originally Posted by *gsferrari* 
_Whatever - it looks stunning and "uber modern" 
	

	
	
		
		

		
		
	


	


_

 

The blue transluscent enclosure looks "surprisingly" good in reality.... the 5mm Purple LED looks cool too... a lot nicer than your bog standard black box. I was thinking of fitting some multicoloured LED's inside the enclosure to highlight the PSU but maybe that's verging on silly? 

  Quote:


  Originally Posted by *gsferrari* 
_Pinky - how about sending a KIT my way..._

 

You'd have to get in touch with WNA gs..... I don't supply their kits (wish I did!) Dr. White can be contacted here

 He'll fill you in on the price etc.

 Mike.


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## 1UP

No need to apologise, Pinkie, your previous enthusiasm has got you a big line of credit to tide you over this dip. I've felt the same way; last night, was having second thoughts about attending the UK meet, but this was probably due to some other things going on in my life in general. 
	

	
	
		
		

		
		
	


	




 Anyhows, I got my assembled and tested MK2 and Cascode PSU today, so I'll be giving a good listen tonight! Don't have much to compare it to anymore, though 
	

	
	
		
		

		
		
	


	




 (sold my MK1 and wallwart)

 Biovizier - how are you liking the Pre-amp and phono amps? How do they compare to other things you've used?


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## 12796

Pretty well - the "preamp" is custom unit comprised of a SE to balanced converter followed by a balanced stepped attenuator and three pairs of buffered balanced output modules. It has no gain. I need three pairs of balanced outputs to drive a pair of Bryston 7B-ST and a pair of Bryston 4B-St to triamp a pair of PMC MB2 monitors (2.4 kW and 92 dB/Wm senstivity way-hey!). This is essentially a volume control bookended by some buffering in the balanced configuration - i.e. combining the best parts of active and passive preamp. The phono is also pretty good. This preamp and phono easily beat Tom Evans Groove / Vibe / Pulse combination - and they are still undergoing ongoing development with David. The phono has developed from his audiophile phono kit but now surpasses it considerably. 

 Nick.


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## 1UP

Thanks for that.

 Well it's obviously early doors but the sound from my new gear is delightful - all as before - musical, warm, detailed, smooth, but I'm getting the feeling the PSU is subjectively lowering the noise floor to an inky black, perfect background. It's pretty special!


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## PinkFloyd

A couple of little surprise visitors arrived today and they've been playing away for a few hours now:





















 I think you've probably gathered from the pictures that the surprise visitors I was referring to are the LM6181 op amps 
	

	
	
		
		

		
		
	


	




 When I first listened to them my immediate impression was that the sound was faster (as if I'd increased a pitch control a notch) and the bass was lighter yet tighter compared with the LM6171. Midrange is absolutely gorgeous and packed full of detail.

 I had a word with David on the phone and was interested to learn that he had also noticed the LM6181 sounded a lot faster than the LM6171. He also says the circuit is not fully optimised for the LM6181 and a couple of resistor values need changing to optimise it to its full potential.

 When I went back for a listen after speaking with David the bass seemed to have filled out a bit so the chip obviously takes a while to stabilise from new. I'm listening now (LM6181 has been in for 4 hours) and I really like the music this chip is making, it's like listening to a high quality NFM (near field monitor) as opposed to a pair of floorstanders. I see what David meant when he said it was a VERY close run thing between the LM6171 and LM6181! It's hard to differentiate between the two and it'll take a few more days before a winner can be declared.

 Remember, the WNA circuit is not fully optimised for the LM6181 and, as it stands, it's hard to pick a clear winner......... I'll have to listen to the LM6181 further in the optimised circuit (2 resistor values need changed) before commenting further but, as it stands, the LM6181 is sounding good..... Very good indeed!! 

 My gut feeling is that the LM6181 will win the day, the more I listen the more I feel this chip is something pretty special. David is working on the circuit to get the best out of the LM6181 as we speak so I'll know the exact values of the two resistors that need changed and will report back after listening to the circuit optimised for the LM6181.......

 Something tells me this is going to be good, very good! 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


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## PinkFloyd

Quote:


  Originally Posted by *1UP* 
_Thanks for that.

 Well it's obviously early doors but the sound from my new gear is delightful - all as before - musical, warm, detailed, smooth, but I'm getting the feeling the PSU is subjectively lowering the noise floor to an inky black, perfect background. It's pretty special!_

 

Glad you like it 
	

	
	
		
		

		
		
	


	




 Enjoy the music.

 Mike.


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## 12796

Hi,

 That was my feeling too as I stated in my original post. If a "cold" LM6181 can run close to a LM6171 in an optimised circuit for the latter then at the end of the day it is probably going to win once it is worn in and the circuit is tweaked. The LM6171 is a bit grey - as comparison with the AD825 showed (which also sounds faster in the midband than the LM6171). Hopefully the LM6181 will combine the best of both worlds - which is why I suggested it to David for my volco and phono stage and got him to slot it into the headamp to check it out. I have received some LM6181 today from David too - should be interesting! 

 Nick.


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## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Hi,

 That was my feeling too as I stated in my original post. If a "cold" LM6181 can run close to a LM6171 in an optimised circuit for the latter then at the end of the day it is probably going to win once it is worn in and the circuit is tweaked. The LM6171 is a bit grey - as comparison with the AD825 showed (which also sounds faster in the midband than the LM6171). Hopefully the LM6181 will combine the best of both worlds - which is why I suggested it to David for my volco and phono stage and got him to slot it into the headamp to check it out. I have received some LM6181 today from David too - should be interesting! 

 Nick._

 

Good music doesn't always equate to good measurements but, in this instance, I feel 90% confident that the LM6181 will deliver once the values for R2 and R3 have been optimised to get the best out of it.

 As I say, my gut feeling tells me that this chip has bags of potential and I think it will add some meat to the bones (and some soul) I've rolled in hundreds of opamps into many circuits over the years but this one is something special (fingers crossed) 

 I guesstimate something like replacing R2 (1K) with 120R and R3 (3.3K) with 2K should be close to the mark but will await the nod from David for the optimum values.

 Mike.


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## Alick

I started to populate my Mk2 PCB tonight. I've got all the resistors, diodes and DIP sockets fitted. Just the transistors, capacitors and pin headers to go. Hopefully the PCB will be finished tomorrow night then I can spend some time on the case and wiring.

 Mike; have you measured the DC offset at the output of the LM6181s out of interest?


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## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I started to populate my Mk2 PCB tonight. I've got all the resistors, diodes and DIP sockets fitted. Just the transistors, capacitors and pin headers to go. Hopefully the PCB will be finished tomorrow night then I can spend some time on the case and wiring.

 Mike; have you measured the DC offset at the output of the LM6181s out of interest?_

 

Haven't measured anything as yet Alick, as I say, they took me by surprise I'll get around to measuring DC offset etc. at the weekend.

 Nice to have a second pair of ears on board re: the MKll....... have fun building and let me know how you find the sound compared with MKl (my entire body has been down for the past couple of months a second opinion of the MKll would be welcome)

 Cheers.

 Mike.


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## GoRedwings19

Damn I wish Iwas good at DIY so I could build one myself.


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## 12796

Good music always equates to good measurements - if the correct thing is being measured  There's no voodoo here just good science and engineering!

 I have slotted the LM6181 into my phono ... will let you know.


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## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Good music always equates to good measurements_

 

I disagree. Just because something measures well it doesn't mean it will automatically sound good.

 Edited for clarity.


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## 12796

Nothing can be measured in theory - your statement seems to an oxymoron . If something measures well in practice but sounds bad then something is not being measured. There has to be a physical reason for something to sound bad - and anything physical can be measured. If we are unable to determine what that is then our measurement or our understanding is at fault. This occurs because the accepted meaurement paradigm is insufficient to charaterise all the variability in performance, i.e. what you find on spec sheets isn't a complete characterisation of a physical device. In addition most engineering is fixed upon linear behaviour for simple signals. Music is a complex signal and the behaviour of the device and the assessment of that complex behaviour is also more complicated. It doesnt necessarily follow that an op-amp that produces good measurements for a simple sine wave under a standard metric will also perform well with a complex system under a more complex metric - hence the disparity between measured performance and sound quality. Standard "measured performance" as encapsulated by spec sheet style measurements is just a very small and highly signal specific subset of all the possible measurements that can be made. Nonlinear signal analysis and interpretation with broad band signals is very difficult - which is why manufaturers prefer to quote simple and easily understood metrics that are soemtimes not indicative of sound quality.

 Nick.


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## gsferrari

OK I just ordered the boards for myself...aunt in london will receive it and ship it to me.

 Yay!!

 I am going all out with the MK-II to nutty levels


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## PinkFloyd

OK,

 Back on subject, here is what's necessary to optimise the circuit if you're going to use the LM6181.

 R3: Replace with 1K resistor (was originally 3.3K)
 R2: Replace with 300R (was originally 1K)

 I've done it and the amp is sounding great, I'll let everything warm up for a few hours before saying any more.


----------



## PinkFloyd

Quote:


  Originally Posted by *gsferrari* 
_OK I just ordered the boards for myself...aunt in london will receive it and ship it to me.

 Yay!!

 I am going all out with the MK-II to nutty levels 
	

	
	
		
		

		
		
	


	


_

 

Nice one GS keep us posted! Nutty levels sounds gooooooood 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_OK,

 Back on subject, here is what's necessary to optimise the circuit if you're going to use the LM6181.

 R3: Replace with 1K resistor (was originally 3.3K)
 R2: Replace with 300R (was originally 1K)

 I've done it and the amp is sounding great, I'll let everything warm up for a few hours before saying any more._

 

same procedure for mkI, mike? i'm asking that just out of curiosity. the wna ha sounds superb already... no urgency to mod it.


----------



## evo_lution

Hi PinkFloyd,

 I've built a couple of CMoys and a Headclone and have been looking at the Chiarra/WNA kits, which do you think is best? I have Senn HD600s.
 Cheers.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_same procedure for mkI, mike? i'm asking that just out of curiosity. the wna ha sounds superb already... no urgency to mod it._

 

Yes, same procedure Udo.


----------



## PinkFloyd

Quote:


  Originally Posted by *evo_lution* 
_Hi PinkFloyd,

 I've built a couple of CMoys and a Headclone and have been looking at the Chiarra/WNA kits, which do you think is best? I have Senn HD600s.
 Cheers._

 

As a dedicated headphone amp the WNA is very good with the HD-600 IMO. The Chiarra is a superb sounding headamp and can also be used as a passive preamp Chiarra features here It's a very hard one to call as I love both amps so I'll have to be diplomatic and say both are equally good. 

 I believe Shaun Williams is now settled in Spain (at last) and business is back to normal...... Williams Hart website so you shouldn't have any problems getting hold of a kit.





*Chiarra:* Ignore the rock it doesn't come with the kit 
	

	
	
		
		

		
		
	


	








 WNA: Please note the WNA kit comes supplied with Welwyn RC55Y resistors and EVOX polypropylene caps..... I just used bog standard parts in this pic.


----------



## PinkFloyd

If any MKl owners want to try the LM6181 then the following resistor changes will be necessary:

 R2: Remove the existing 1K resistor and replace with a 300R resistor
 R3: Remove the existing 3.3K resistor and replace with a 1K resistor

 Do this for both channels:


----------



## PinkFloyd

Nice, very nice indeed. The WNA has been playing away with the LM6181 (circuit optimised for it) for a few hours now and I like it a lot. It's virtually identical to the LM6171 except for an added degree of warmth which is very welcome. The LM6171 can sometimes sound slightly anaemic, the LM6181 adds some meat to the bones IMO and brings out the "emotion" in the music.

 There's a liquidity and fluidity to the sound which was lacking with the LM6171..... one head-fier classed the LM6171 as "lacking soul" well........ say hello to the LM6181, everything the LM6171 is but with added soul! This puppy has managed to get the hairs on the back of my neck to stand up a couple of times today (listening to Roger Waters "in the flesh" shine on you crazy diamond) awesome stuff! The LM6171 never managed that so I'll have to declare the LM6181 the winner IMO.... "the chip that makes the hairs on the back of your neck stand up!"

 Thanks to biovizier for bringing this chip to the attention of Dr. White and fellow WNA'ers.. much appreciated Nick.

 The R3 resistor value is spot on but I'll be reducing the R2 (300R) value to around 260R to increase the gain a tad....... it's a bit low for me with 300R. I'm having to listen at 11 o' clock on the volume control instead of 9 o' clock to acheive the same level of volume..... no big deal and easy to rectify..... 300R is a good starting point.

 Finally the added bonus....... the LM6181 is a quid less than the LM6171! It's not often that upgrades are cheaper than their predecessor.

 Thanks biovizier.

 Mike.


----------



## StevieDvd

Your picture above shows R2 as a 330R 
	

	
	
		
		

		
		
	


	




 If these affect the gain then it's likely to be the ones I snipped and piggy-backed when I adjusted the gain (as I'm sure you'll recall that far back).

 Are the LM6181 generally available or only via WNA?

 And what about the rail splitter - another LM6181?

 Sorry to here you won't be making the Nottingham meet I was looking forward to meeting you.

 Steve


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Your picture above shows R2 as a 330R 
	

	
	
		
		

		
		
	


	


_

 

not any longer, thanks for pointing that out Steve. 

  Quote:


  Originally Posted by *StevieDvd* 
_If these affect the gain then it's likely to be the ones I snipped and piggy-backed when I adjusted the gain (as I'm sure you'll recall that far back)._

 

Sure do recall it 
	

	
	
		
		

		
		
	


	




 WNA gain settings are explained here 

  Quote:


  Originally Posted by *StevieDvd* 
_Are the LM6181 generally available or only via WNA?_

 

Haven't looked around as yet Steve but they are available from WNA at £2.50 a pop I believe.

  Quote:


  Originally Posted by *StevieDvd* 
_And what about the rail splitter - another LM6181?_

 

Haven't tried an LM6181 in the splitter as yet will get around to that next weekend.

  Quote:


  Originally Posted by *StevieDvd* 
_Sorry to here you won't be making the Nottingham meet I was looking forward to meeting you._

 

likewise Steve.


----------



## 12796

PF,

 I have been running the LM6181 in the WNA phono stage for a few hours and the results are quite remarkable. It's very fast bright and clear sounding - a big improvement on the AD811. Sounds much tighter and more dynamic. Can't wait to see what the next week brings!

 Nick.


----------



## PinkFloyd

Alick,

 Fit the LM6181 in from scratch substituting R2 and R3 with the recommended values...... I'd go for 250R for R2.

 This is one very good sounding chip indeed.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_PF,

 I have been running the LM6181 in the WNA phono stage for a few hours and the results are quite remarkable. It's very fast bright and clear sounding - a big improvement on the AD811. Sounds much tighter and more dynamic. Can't wait to see what the next week brings!

 Nick._

 


 It's a superb chip for use in the WNA circuit........ no doubt.

 Next week will probably focus on the value of R2.......... IMO 300R isn't low enough......... 220R - 250R is the range I'm looking at (My money would be on 250R "215R being optimum for me" )

 As it stands the LM6181 sounds better than the LM6171 by a whisker.

 Mike.


----------



## PinkFloyd

I've been messing about with the value of R2 with the LM6181 on board and 260R seems a pretty good value for me and is similar to the gain the LM6171 had with R2 being 1K. The recommended 300R starting point gives a good control on the volco but 260R has got a better feel to it for my tastes.

 The WNA with LM6181 has been playing for about 100 hours non stop now and I don't think I'll be retrofitting the LM6171. As mentioned before, the LM6181 does everything the LM6171 did but with a bit more warmth and emotion..... it's here to stay. I haven't heard back from Dr. White with his opinions of the LM6181 and can't wait to hear which one of the 2 opamps he prefers.

 Not a lot left to do with the WNA now apart from changing the caps and resistors..... I did say at the beginning of the thread that if the amp sounds incredible with standard parts then I'd replace them with more exotic components........ well it does so I will! 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## 12796

I am going to be swapping in the LM6181 all the way through my volco and phono - Dr White seems to be of the opinion the the LM6181 is superior also.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I am going to be swapping in the LM6181 all the way through my volco and phono - Dr White seems to be of the opinion the the LM6181 is superior also._

 

It's not "superior" per se ....... it's similar to the LM6171 but different in many ways (how's that for an oxymoron!) Some may like the clinical, fast, unforgiving and microscopic insight that is the LM6171 whilst others may like the same qualities with a touch of emotion and soul... if so the LM6181 is the order of the day...... neither of them is superior to one another they just do things in a different way.....

 One difference I have noticed between the MKl and MKll is the space and inky black silence between instruments the MKll brings about...... the sound is so clean you can pump frightening levels into your eardrums and not even realise how loud it is....... this is a sign of a quality amp.... The additional decoupling probably accounts for this........ every instrument has air around it and distortion cannot be heard (probably cause there's no distortion to be heard) even the most maniacal crescendos are easy on the ear, even at very high levels.

 I, originally, thought this was something to do with the setting of the gain but.... No. This amp gives you the music, the whole music and nothing but the music, hearing is believing and I urge you to have a listen to the WNA....... you'll never look back I can guarantee it.

 Class on a stick.

 revised:

 MKl: 9 / 10
 MKll: 11 / 10


----------



## PinkFloyd

Meant to add,

 Had a conversation with Dr. White earlier and LM6181 will now supersede the LM6171 in all Head-Amp kits.

 All the best.

 Mike.


----------



## Alick

I've ordered my LM6181 today (cheque's in the post). Build should be pretty much complete by the end of this weekend (barring domestic life intruding into build time again 
	

	
	
		
		

		
			





 ).


----------



## 12796

Steady on! The LM6181 takes about a week (at least) to bed in ... plus the wna mk II was specifically designed around the LM6171. If the next version is designed around the LM6181 - which is CFB and therefore has different characteristics - then the improvement may become unequivocable. The two chips are not being compared on a level playing field as yet.  I am using LM6171 in my volco and will swap them out for LM6181 in the next few weeks - that may actually give a fairer comparison as the balanced module is not optimised for either chip yet. Certainly there is room for improvement on the lm6171 given my comparisons with the ad825. Which headphones are you using and which source with the WNA headamp? I suggest if possible you try to vary these factors as well to see how that changes the perspective on the relative merits of each chip - given that no source / sink is perfect then it's prudent to check that it is not a limiting factor on the comparison. I only have one vinyl source unfortunately so I wil be interested to hear your results. Have you tested with cd source only or also with vinyl?


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Steady on!_

 






  Quote:


  Originally Posted by *biovizier* 
_The LM6181 takes about a week (at least) to bed in ... plus the wna mk II was specifically designed around the LM6171._

 

MKll is in effect a MKl the only difference being extra decoupling. The MKl was designed around the OPA134 / OPA627 breed of chips. The circuit only needed minor modification to get the LM6171 to operate optimally in the circuit and these modifications included biasing the opamp into class A (changed I2 from a 3.5mA to a 5.6mA constant current diode and changed R6 from 120R to 75R resistor) replaced R4 with a zero ohm link and fitted output caps...... as easy as that.

 As I say, the MKll is essentially a MKl with added decoupling..... to optimise the MKll circuit for the LM6181 simply involves scaling down the gain setting resistors so that the feedback resistor (between o/p and inverting input) is 1k. This means that if the feedback resistor was 3.3k and the resistor from inverting input to ground was 1k (for gain of 4.7), you would have to scale the 3.3k down to 1k, and the 1k down to 300R (or nearest preferred value) to keep the ratio the same...... *this has been done*.

  Quote:


  Originally Posted by *PinkFloyd* 
_Had a conversation with Dr. White earlier and LM6181 will now supersede the LM6171 in all Head-Amp kits._

 


  Quote:


  Originally Posted by *biovizier* 
_ If the next version is designed around the LM6181 - which is CFB and therefore has different characteristics - then the improvement may become unequivocable._

 

The circuit has been optimised for the LM6181 as above 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *biovizier* 
_ Which headphones are you using and which source with the WNA headamp?_

 

Headphones:
 Sennheiser HD-600
 Grado SR-60
 AKG K-501

 Sources:
 Marantz CD-17 ki signature
 Denon DCD-835


  Quote:


  Originally Posted by *biovizier* 
_I suggest if possible you try to vary these factors as well to see how that changes the perspective on the relative merits of each chip - given that no source / sink is perfect then it's prudent to check that it is not a limiting factor on the comparison. I only have one vinyl source unfortunately so I wil be interested to hear your results. Have you tested with cd source only or also with vinyl?_

 

I've only listened with CD as a source (both Marantz and Denon) and through 3 different pairs of headphones, both LM6171 and LM6181 kick ass whatever combo I use.... 

 Mike.

 Edit: Just out of interest Biovizier, do you own a WNA MKll head-amp?


----------



## 12796

All of the previous chips are vfb - perhaps a cfb chip will open up whole new research vistas for the next iteration! 
	

	
	
		
		

		
		
	


	




 Tailoring can involve fundamental design changes as well as just changing a few resistor values. Also - give it a chance to wear in! The LM6171 didnt reach its potential for well over a week of constant use and continued to improve for at least 2. Which areas do you think the LM6171 still has the edge in and how are they changing over time now? 

 Also, some other change or addition may be made that will suddenly reveal that a limitation lay elsewhere in the unit, or that two aspects were compensating for each other and this could lead to a reappraisal. Certainly the fact that the LM6181 sounds faster then the LM6171 in combination with a couple of things that are "in development" is of particular interest to me. There is likely a limit I have discovered elsewhere that when rectified might suddenly reveal that the performance advanatage of the LM6181 was much greater than previously imagined but was obscured by a bottleneck. OR maybe not. Or it may be that CD only listening biases the results (i.e. OPA627 makes a bright cd player sound palatable but is a pretty naff sounding op-amp otherwise). I have to determine all the unknowns to make the correct choice.


----------



## 12796

Edit: I have the wna phono and "preamp" but I may also be purchasing the headamp soon. In addition I may use the buffer amp in the preamp (which is the basis for the preamp and the headphone amp). So it's still relevent. Just about.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Edit: I have the wna phono and "preamp" but I may also be purchasing the headamp soon. In addition I may use the buffer amp in the preamp (which is the basis for the preamp and the headphone amp). So it's still relevent. Just about._

 

As soon as you get the WNA head-amp I'll be interested to hear what you think of it Nick. I've been listening to head-amps for many years and have been heavily involved with the WNA head-amp for the best part of a year now (have a read through the original WNA thread). 

 I really appraciate your input re: the LM6181 but, with respect, I don't need to be told how to evaluate an opamp.... the LM6181 has been burning in for about 120 hours (with music playing) and that's enough time to establish whether it's a keeper or a throwaway.... It's good, not miles better than the LM6171 but different... I like it and will continue using it.... whether others will like it, well I'll let "their" ears decide. They're only £2.50 a pop so it won't break the bank rolling a couple in for a try.

 Cheers

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_ Which areas do you think the LM6171 still has the edge in and how are they changing over time now?_

 

I didn't say it had the edge..... read a few lines up 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *PinkFloyd* 
_It's not "superior" per se ....... it's similar to the LM6171 but different in many ways (how's that for an oxymoron!) Some may like the clinical, fast, unforgiving and microscopic insight that is the LM6171 whilst others may like the same qualities with a touch of emotion and soul... if so the LM6181 is the order of the day...... neither of them is superior to one another they just do things in a different way....._

 


  Quote:


  Originally Posted by *biovizier* 
_I have to determine all the unknowns to make the correct choice. 
	

	
	
		
		

		
		
	


	


_

 

You'll only manage that by buying a WNA head-amp and using your ears


----------



## 12796

I just think the LM6171 has a few issues and your findings seem to be different - just curious why that might be. Dont take it personally 
	

	
	
		
		

		
		
	


	




 I am not casting aspersions on your op-amp assessment - just trying to determine the differences. They might be in my setup and need to be addressed. Rigourously!


----------



## 12796

I surely will but I am waiting to sort the phono and preamp first - otherwise upstream components will muddy the waters. The same types of tweaks and concepts are used. As I said the preamp and headphone amp are derived from (or even identical - not sure) the same circuit so whats good for one is good for the other. They are directly comparable so by finalising the preamp using the buffer amp I will have also then have finalised my headamp.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I just think the LM6171 has a few issues and your findings seem to be different - just curious why that might be. Dont take it personally 
	

	
	
		
		

		
		
	


	




 I am not casting aspersions on your op-amp assessment - just trying to determine the differences. They might be in my setup and need to be addressed. Rigourously!_

 

I'm not taking it personally Nick but this thread is about the WNA MKll head-amp..... The LM6171 may sound completely different in your application and I can only comment on how a chip sounds in the WNA head-amp. I suggest my findings may be different to yours as I am listening to the head-amp and you are not, you're probably listening through loudspeakers?

 I've covered the attributes of the LM6171 "extensively" in the original WNA thread  I'm not repeating myself over and over again so have a glance through that thread.... there's plenty there.

 I'll obviously go into a lot more detail re: the attributes of the LM6181 after say 500 hours but, as it stands, my initial appraisal is "it does what the LM6171 does though it's slightly faster with a bit more warmth, soul and emotion"

 I'll expand on that statement if there are any major changes after 500 hours.

 All the best.

 Mike.


----------



## 12796

I look forward to hearing your findings


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I look forward to hearing your findings 
	

	
	
		
		

		
		
	


	


_

 

I look forward to presenting them


----------



## Alick

Well. the progress on my Mk2 has been a little slower than I'd have liked. I started to populate the PCB last weekend but family and domestic obligations, coupled with a sudden desire to use LM6181s (which I didn't have) halted progress until today. The LM6181s and required resistors for the op-amp change arrived in the post this morning (thanks David!) so I intended to complete at least the PCB and hopefully the whole amp. Well, I got the PCB finished, but a knock at the door turned out to be a friend from Inverness who I hadn't seen for a year, so that kyboshed any further progress. I'll try again tomorrow.

 Anyway, the PCB is as well made and easy to populate as the original Mk1 (that's very easy), although getting a satisfactory result hooking up wires between the rail-splitter and the PSU inputs for the amplifier channels took a few attempts until I was happy. It would have been easier had I bought enough pin headers to cover this requirement, but I'm a cheapskate and didn't. To prove my progess, here are a couple of quick (read poorly taken) photo's showing the populated board and the PSU earth hook-up wires tacked to the underside of the PCB. More progress will be reported when I make any. (Please note that the PCB hasn't been cleaned yet).


----------



## PinkFloyd

Coming along nicely Alick 
	

	
	
		
		

		
			





 Agreed the hook up from the rail splitter to P3 is a bit of a fiddly pisser but I can understand why it's been implemented that way but can't understand why David didn't make it easy and make that part of the board "jumperable" with zero ohm resistors. The hook up wire is a wee bit tight for comfort (space between pads) and time consuming.... I see you hooked up 0V on the underside of the board... good idea, leaves plenty of space between +V & -V on the top of the board.... I used very thin PTFE wire and hooked up all three (0V +V -V) on the top of the board.... one things for sure, you don't want to use thick wire from the rail splitter to P3, one loose strand out of place and POW goes your PSU...... I agree with you Alick...... I found this part of the build very fiddly and, quite frankly, frustrating considering the board could have been designed to use jumpers, This is one part of the design David will hopefully address. Even with pin headers it would be a bloody fiddly job ..... Jumpers are the way to go......

 I notice you're using the BC caps? They're pretty good and reasonably priced did you get them from Rapid? From the size of the two yellow Nitai non polars I would guesstimate that they are 16V 1000uF? I can see the RC55Y's (300R and 1K) are in place for the LM6181 what resistors did you use for the rest of the board? They look like Trueohm 0.1% 15ppm from the pic 
	

	
	
		
		

		
		
	


	




 Looking good Alick I can't wait to hear what you think of the LM6181...... I've still got them in place and am VERY happy with the sound quality indeed...... Try the MKll with the LM6171 also, there's not much in it and it'll be interesting to learn your opinion.

 Look forward to it.

 All the best.

 Mike.

 EDIT:

 Thanks for the pic it will show the difference between the PCB1 and PCB2...... they are both* identical * with the exception that PCB2 has provision to board mount the volco and head-socket....... other than that they are identical. It's good that two boards are available to cater for all applications:





 PCB1
 PCB1 is similar to the previous WNA (and can also be used as a buffer amplifier) except the pcb is a little larger; there are now "two" pairs of output devices per channel to deliver a lot more grunt into low impedance 'phones; the rail splitter is now preceded by a capacitance multiplier to make performance less dependent on the quality of the external power supply so you can now get fantastic performance using a bog standard PSU; the output caps now mount on the pcb; and each channel is now completely independent ( i.e. the amp is dual mono ) so that you can have one power supply per channel. The PCB1 is ideal for people who want to use a stepped attenuator or want to build a fully balanced system using 2 boards... It can also be used as a Dual Class A Buffer Amplifer.





 PCB2
 PCB2 is the same as PCB1 except that the potentiometer and headphone jack mount on the pcb.


----------



## Alick

Quote:


 one things for sure, you don't want to use thick wire from the rail splitter to P3, one loose strand out of place and POW goes your PSU 
 

I used solid core, just in case.
  Quote:


 I notice you're using the BC caps? They're pretty good and reasonably priced did you get them from Rapid? From the size of the two yellow Nitai non polars I would guesstimate that they are 16V 1000uF? I can see the RC55Y's (300R and 1K) are in place for the LM6181 what resistors did you use for the rest of the board? They look like Trueohm 0.1% 15ppm from the pic 
 

I got all the resistors and cap's from Rapid except for the Nitais (yes, I went for the 1000uF) and the RC55Ys. All of the resistors are 0.1% except for R6, R12 and R13 for which Rapid had no stock so I just used 1%.
  Quote:


 Looking good Alick I can't wait to hear what you think of the LM6181...... I've still got them in place and am VERY happy with the sound quality indeed...... Try the MKll with the LM6171 also, there's not much in it and it'll be interesting to learn your opinion. 
 

I've got both and intend to compare. It should be easy as David reckons that the optimised R2 and R3 for the LM6181 suits the LM6171 just as well. Nearly there and itching to listen.


----------



## 12796

Dr White makes a very nice balanced stepped attenuator - highly recommended. From my own experiences I would say this would be a very worthwhile but expensive upgrade compared with standard pots - prob add £100 or so to the cost but would make a big improvement. I have requested one in my version of the headamp (when I get around to ordering it  ). I am running his preamp in balanced mode - he also makes single ended to balanced converters that can be used to convert the buffer unit to balanced at a lower cost. I would be interested if anyone compares a standard PSU with the cascode PSU with the capacitive multiplier arrangement.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I used solid core, just in case._

 

Yet another great idea Alick 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *Alick* 
_I've got both and intend to compare. It should be easy as David reckons that the optimised R2 and R3 for the LM6181 suits the LM6171 just as well. Nearly there and itching to listen. 
	

	
	
		
		

		
		
	


	


_

 

What values did you end up using for R2 & R3?


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Dr White makes a very nice balanced stepped attenuator - highly recommended. From my own experiences I would say this would be a very worthwhile but expensive upgrade compared with standard pots - prob add £100 or so to the cost but would make a big improvement. I have requested one in my version of the headamp (when I get around to ordering it  ). I am running his preamp in balanced mode - he also makes single ended to balanced converters that can be used to convert the buffer unit to balanced at a lower cost. I would be interested if anyone compares a standard PSU with the cascode PSU with the capacitive multiplier arrangement._

 

Hi Nick,

 I originally wanted to use the stepped attenuator but it was too bloomin large to fit into the enclosure I had 
	

	
	
		
		

		
		
	


	




 I may well buy one and house it in its own enclosure (offboard) how many steps will you be using? I'll probably go with 24 for starters.

 I haven't tried the Cascode PSU and would really love to give one a road test before actually buying one.. the one I use at the moment is the Calex open frame built into a translucent blue enclosure, sounds good to me and cost around £40 to build, it would be interesting to compare it with the Cascode PSU.... here are a few close up pics of the innards:


----------



## 12796

I am using 24 steps - that is more than enough. I am already using cascode PSUs and I am about to fit CM's to all my units. I am curious about how much the CM removes dependency on the psu as I may be about to upgrade the cascode 
	

	
	
		
		

		
		
	


	




. Dr White would lend you a cascode if you wanted to try one.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I am using 24 steps - that is more than enough. I am already using cascode PSUs and I am about to fit CM's to all my units. I am curious about how much the CM removes dependency on the psu as I may be about to upgrade the cascode 
	

	
	
		
		

		
		
	


	




. Dr White would lend you a cascode if you wanted to try one._

 

I'll try one out in the summer Nick, maybe by that time my enthusiasm will have returned.. as it is, at the present time, I'm happy with the WNA and am enjoying the music and don't see any immediate areas of the sound that "need" improving. One could go on forever trying to get every last ounce out of a piece of equipment but there comes a stage where the law of diminishing returns comes into play. 

 Mike.


----------



## 12796

Indeed - sometimes you just have to sit back and enjoy the fruits of your labours... lest the means become the end. 

 Sometimes the law of diminishing returns can be broken by exceptional products, but they are very rare. Certainly all of the changes that have been made to the audiophile phono unit have changed it beyond belief and there is still some way to go - some of the future mods will also find their way into the headphone amp I am sure at some point. I think the LODR sets in quickly with tweaking... evolution of the sound as it were. To get a revolution it requires something more substantial I guess. 

 As you say the most immediate concern with any system is to remove any obvious flaws that impair listening. After that everything else is a a luxury but not a neccesity.


----------



## Alick

Quote:


 What values did you end up using for R2 & R3? 
 

1k0 and 249R.


----------



## Alick

Finished! I grabbed the opportunity of being the only one in the house today to finish my Mk 2. All I had left to do was the hook-up wiring. The co-ax cable supplied by WNA (which I believe is standard with the kit?) is a joy to work with and makes for a really neat job (well, as neat as I'm capable of). Joy of joys, it worked first time and, although I haven't listened too much yet, first impressions are of a 'fuller' sound than the Mk 1. I fitted the LM6181s to start with but will do a comparison with the LM 6171s soon. The amp is burning in as we speak and should have 5 or 6 hours on the clock before my first serious listening session with it later tonight. Here are some pictures if anyone's interested. (I'll put the lid on after I've finished this post).


----------



## BrokenEnglish

wow... another one... hope you'll enjoy it, alick! what's that impressive 4-pole switch on the backside for? second input?


----------



## Alick

Quote:


 what's that impressive 4-pole switch on the backside for? 
 

I'm planning to use it for a cross-feed. There's enough room at the back of the case.


----------



## 12796

Alick,

 Looks good - is that a monarchy super dac you are using? Do you take a digital output from a transport feed it into the dac and then into the headamp? I am curious as one of the things I have discussed with Dr White is building in a dac into the headamp so my portable would just be used as a transport and knock the sound quality up another notch. I did look at a few portable dacs and dac daughterboards - have you any experience in this area? 

 I look foreward to hearing your results!

 Nick.


----------



## Alick

It's an M-Audio SuperDAC 2496. It's a failrly well respected (semi)-pro product and it works very well in a domestic environment IMHO. I looked around for ages for a DAC to use with my wireless Squeezebox and nearly settled on the Art DI/O, before I stumbled on some reviews for the M-Audio. I don't use a CD transport anymore. My system uses FLAC files streamed wirelessly to the Squeezebox. It works extremely well and sound great to my ears. I was also considering the April Music Stello DP200 DAC/Pre/Headphone Amp , but it was £800 and they didn't have UK distribution set up when I was buying.


----------



## 12796

Thanks,

 I saw the m-audio a while back too. It looked like a high performance no nonsense sort of product. I haven't really caught onto the digital age yet... I have just a 100 CDs and 2000 vinyl! So all these file streaming and wireless audio developments have passed me by a bit. Think I will stick with my deck for the time being 
	

	
	
		
		

		
		
	


	




. I plan dual use for my headamp - attach to the WNA volco for use at home or attach to my portable for in the gym. I already have a Pink Triangle dac at home so I wanted something portable and battery powered for the gym use. I have seen some dac daughterboards online, like the piccolo. Could the monarchy be used from a battery supply? i.e. is it powered via a plug in dc adapter?

 Nick.


----------



## Alick

Update: The lid's on, I'm happy. The amplifier was very easy to build with only the wire links required between the rail-splitter and the amplifier channels causing any trouble. The instructions are very clear and comprehensive and the supplied co-ax cable makes hooking up the PCB and ancillaries very straight-forward, tidy and effective.

 The differences between the Mk1 and Mk 2 I built are:
 Redesigned output stage.
 Redesigned rail splitter with capacitance multiplier.
 Co-ax rather than plain wire in signal paths.
 LM6181 instead of LM6171 in audio path.
 LM6171 instead of TL071 in rail-splitter.
 Nitai output capacitors instead of ALCAP.
 Input capacitors (4u7 polyester) instead of wire links.

 I burned the amp in for six hours prior to a 3 hour listening session on Saturday night and I've enjoyed subsequent short sessions. Initial impressions are of a significat improvement over the already excellent Mk 1. The sound seem to be better defined, more spacious and individual instruments are even easier to follow. I'm again discovering new detail on old favourites. On Carol Laula's "Naked" live album, I used to hear PA hum at the end of one track. It's now obvious that there is light hum fairly much all through several tracks. Gestures, breathing and little instrumental flourishes have appeared from nowhere. I'm really enjoying this amp. It seems to marry so well with the HD650s. I'll be trying LM6171s soon to see what difference they make and I'll post more impressions as she burns in. 

 Well done David, this is a really good redesign.


----------



## Henry Morgan

I'm sticking with LM6171 as although the top & mid detail was still as good with LM6181 I thought it made the bass a bit too heavy. (Using Grado SR60 which some say are a bit light on the bass!)
 I changed the resistors as advised but I'm otherwise very happy with my recently built Mk2 WNA.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Update: The lid's on, I'm happy. The amplifier was very easy to build with only the wire links required between the rail-splitter and the amplifier channels causing any trouble. The instructions are very clear and comprehensive and the supplied co-ax cable makes hooking up the PCB and ancillaries very straight-forward, tidy and effective.

 The differences between the Mk1 and Mk 2 I built are:
 Redesigned output stage.
 Redesigned rail splitter with capacitance multiplier.
 Co-ax rather than plain wire in signal paths.
 LM6181 instead of LM6171 in audio path.
 LM6171 instead of TL071 in rail-splitter.
 Nitai output capacitors instead of ALCAP.
 Input capacitors (4u7 polyester) instead of wire links.

 I burned the amp in for six hours prior to a 3 hour listening session on Saturday night and I've enjoyed subsequent short sessions. Initial impressions are of a significat improvement over the already excellent Mk 1. The sound seem to be better defined, more spacious and individual instruments are even easier to follow. I'm again discovering new detail on old favourites. On Carol Laula's "Naked" live album, I used to hear PA hum at the end of one track. It's now obvious that there is light hum fairly much all through several tracks. Gestures, breathing and little instrumental flourishes have appeared from nowhere. I'm really enjoying this amp. It seems to marry so well with the HD650s. I'll be trying LM6171s soon to see what difference they make and I'll post more impressions as she burns in. 

 Well done David, this is a really good redesign._

 

Nice job you've done there Alick!

 Sorry about the time taken to congratulate you on your fine build but I've been unable to access Head-Fi the past few days. My MKll is down in Nottingham at the moment and you only know just "how good" it is when it's gone! Captain has done a comparison between the WNA and ANT Amber in the amplification forum and I tend to agree with a lot of what he has to say about it, I don't know if you've read it but if not, have a read. 

 It really isn't a good amp to compare side to side to a more immediate sounding "in your face" amp....... the WNA is wonderfully neutral and it's only after a prolonged listen that its qualities begin to shine through..... that's usually the way of it.... equipment that sounds upfront and "thrilling" through a comparator in a Hi-Fi shop usually ends up turning out to be harsh and fatiguing once you've bought it and listened to it for a while. The neutral gear may not give you an immediate "in yer face" hit but over a period of time the subtle nuances make the hairs on the back of your neck stand up.

 Give the MKll a couple of weeks Alick..... It's a creeper and once it kicks in it's a definite keeper. My MKll should be back from the Nottingham meet one of these days (no hurry Kirk) I've got a couple of AD 843's to try in it, Looking at the spec sheet I don't expect great things from the AD 843 but you never know...... others here are rating the 843 so may as well give it a go. As I say I'm not expecting fireworks.


 All the best.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *Henry Morgan* 
_





 I'm sticking with LM6171 as although the top & mid detail was still as good with LM6181 I thought it made the bass a bit too heavy. (Using Grado SR60 which some say are a bit light on the bass!)
 I changed the resistors as advised but I'm otherwise very happy with my recently built Mk2 WNA._

 

First off...... Welcome to Head-Fi sorry about your wallet Henry Morgan (a traditional greeting I have never understood...... why should this place make me want to part with money?) 

 Strange,

 I actually found the LM6181 to provide an even leaner, tighter and more musical bass than the LM6171. I haven't listened through Grados but through HD-6**'s and AKG K-501 the bass certainly can't be described as "heavy"...... there is the possibility that I'm going deaf however.

 I'll roll in the LM6171's once the amp is back with me and will "really" go to town comparing the 6181 to the 6171...... as it stands though (from memory) the LM6181 has an airier, pacier and lighter bass than the LM6171 (with 300R and 120R phones)

 What value output caps are you using Henry?

 All the best.

 Mike.


----------



## Alick

Quote:


 I've been unable to access Head-Fi the past few days. 
 

I thought you'd gone AWOL. 
	

	
	
		
		

		
		
	


	




 You've got mail (PM) BTW.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I thought you'd gone AWOL. 
	

	
	
		
		

		
		
	


	




 You've got mail (PM) BTW._

 

I did go AWOL but it was compulsory absence if you catch my drift?


----------



## Henry Morgan

Thanks for the welcome Pink Floyd. In answer to your question I'm using 1000uF non-polarised electrolytics. Do you think I've overdone it a bit & should put the smaller ones back in? I used 1000uF because the Grados are low impedance (32ohms) & thought that would improve things.


----------



## Alick

I've used 1000uF in both my WNAs and they are fine with Grados and HD650s.


----------



## PinkFloyd

Quote:


  Originally Posted by *Henry Morgan* 
_Thanks for the welcome Pink Floyd. In answer to your question I'm using 1000uF non-polarised electrolytics. Do you think I've overdone it a bit & should put the smaller ones back in? I used 1000uF because the Grados are low impedance (32ohms) & thought that would improve things._

 


 Hi Henry,

 1000uF is ideal, Maybe the LM6181 "is" bassier than the LM6171 with the Grado phones but with the senns and AKG phones the bass is even tighter than it was with the LM6171. I'll have a real good listen to the 2 opamps again once the amp returns.

 Mike.


----------



## PinkFloyd

The amp arrived back safe and sound from the Nottingham meet and I couldn't wait to hear music through it so I connected her up and was very underwhelmed indeed 
	

	
	
		
		

		
		
	


	




 It was not how I remembered it at all sounding pale, thin and lifeless. I scratched my head for a bit and could only come to the conclusion I must have "got used" to the LM6181 prior to sending the amp down to Nottingham.

 Everything about the sound seemed different to what I'm used to hearing from the WNA... for starters the volume control had to be turned up to about 2 o'clock to get any decent level of sound out of it, the bass was very light and the overall sound was thin and lacked dynamics and "grunt"

 I tried listening to my AKG K-501's powered by the LM6181 WNA and it was an absolutely lifeless listen.... no bass, flat midrange and .... well, just plain "weedy" even turning her up to the 4 o' clock position on the volco couldn't provoke anything decent from the K-501.

 hmmmm....... weird stuff! I must admit (prior to the Nottingham meet) that It was necessary to crank the volco up a couple of extra notches with the LM6181 but I didn't realise, at the time, just how weedy the sound actually was compared to the WNA with LM6171 onboard.

 I confirmed this last night by removing the LM6181, I retrofitted 1K in R2 and 3.3K in R3 and rolled in the LM6171.... connected her to my source, plugged the phones in and "bingo" the balance, the body, the volume.... everything was back to normal as if by magic... 11 o' clock on the volco got the senn HD-600's pumping my eardrums loud style! More like it!!

 Tried the K-501's and, quite franky, still pretty thin sounding though nowhere near as watered down as they sounded with the LM6181 on board.... LM6181 is crap with the K-501, full stop.

 The HD-600 and LM6171 combo is pure magic of that there's no doubt. In an attempt to inject a little extra drive into the K-501 I upped the quiescent current by 25% (replaced R5 (120R) with a 160R and R6 (75R) with a 100R

 Very little effect on the K-501 but certainly a big improvement with the HD-600!! definitely more drive, more energy and more pizzaz to the sound.... not just a slight improvement but a marked one..... I may even up the quiescent current another 25%, may even improve the Senns further... what the heck it's worth a try 
	

	
	
		
		

		
		
	


	




 Once I've finished playing about with the quiescent current and am satisfied that all's well with the LM6171 / Senn HD-600 combo I'm going to give the Burr Brown OPA627's another shot in the MKll. I've ordered the military grade OPA627BP's so the DC offset should be pretty close to zero..... I think it's worth giving them a tryout in the MKll, they sounded a bit syrupy in the MKl but it may be a different story with the MKll, who knows...... it's worth a try!

 The good weather must have returned I've got an insatiable urge to opamp roll!! 

 Rock and roll!!

 Pinkie.

 EDIT: If you up the quiescent current by 25% it's probably best to fit clip on heatsinks to the transistors as the core temperature rises from 60c to 80c


----------



## BrokenEnglish

hm, mike, personally i don't believe in the opa627. they tend to fade out those nice details, you have with your lm6171. the particular bass problem you're realizing with the akg501 reminds me of mine with the dt880 & mkI-wna (no probs with the hd650!). i'd be interested if it could be cured by replacing the output caps. in similar cases i read recommendations to add some insane capacitance (usually 2-10F), paralleled with some smaller mkp caps in descending order. maybe i'll test it some time later.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_hm, mike, personally i don't believe in the opa627. they tend to fade out those nice details, you have with your lm6171._

 

I wasn't overly impressed with the 627's in the Mkl but you never know, they may be better in the Mkll. One thing I have been experimenting with today is the value of R11 (R9 in the MKl) at the moment it's a 12V incandescent 60mA lamp... I whipped them out and they measure 21ohms so, in effect, the output resistance of the WNA is 21ohms.

 As we all know some amp manufacturers fit 120ohm output resistors in accordance with IEC 61938 international standards which recommend that headphones should expect a 120ohm source regardless of the headphone's own impedance. Other manufacturers try to get the output impedance as close to zero as possible.

 Well, I started off by removing the incandescent lamps and replaced them with zero ohm links....... sounded good through the HD-600 though, for some reason, whenever the volume control went past 11 0' clock it introduced hiss but "only" when my finger was in contact with the volume knob.... as soon as I removed my finger all was ok 
	

	
	
		
		

		
		
	


	




 I then went to the opposite end of the scale and fitted 120ohm resistors, slightly deeper bass and more accentuated treble.... one things for sure, the 120R output resistor makes a difference, whether it's good or bad I've yet to decide...... looks like the next few evenings will be spent evaluating the best value of output resistor to use with the Senn HD-600's 
	

	
	
		
		

		
		
	


	




 Are there any output impedance experts in the house? Some manufacturers swear by zero ohm output impedance whilst others insist on 120ohm as per IEC 61938 international standards. What would be the best "catchall" value to use? (cause less offence to a wide range of headphones) I notice that quite a lot of the commercial manufacturers go with 120 ohm output impedance whereas the majority of DIY'ers prefer as close to zero as is possible output impedance...... What output impedance would make the amp more "bullet proof" with all headphones....... zero ohm or 120ohm (I don't mean which OI will sound better but which output impedance is the most "stable" with all headphone impedances?) 

  Quote:


  Originally Posted by *BrokenEnglish* 
_the particular bass problem you're realizing with the akg501 reminds me of mine with the dt880 & mkI-wna (no probs with the hd650!). i'd be interested if it could be cured by replacing the output caps. in similar cases i read recommendations to add some insane capacitance (usually 2-10F), paralleled with some smaller mkp caps in descending order. maybe i'll test it some time later._

 

Let us know your findings Udo and be sure to upload pics of the 10 Farad caps


----------



## Syzygies

Thank you for raising this issue, it's very frustrating reading headphone reviews that don't explore this territory.

 I hadn't been aware of the 120 ohm "standard", so I had imagined a different explanation: Most headphones are designed with as low an impedance as possible to make them usable with a broad range of amps, e.g. most commercial portable gear couldn't drive any headphone on the market with 120 ohms in the way.

 That was just a guess, trying to explain why so many of my headphones tightened up with 75 ohms of output resistance.

 In a different thread, Tangent and I discussed an output resistance rotary switch, with multiple settings. This would make it easy to dial in different sounds for different recordings. I think this is a great idea, it's on my list of future experiments. I laid out a surface mount "volume, trim" stepped attenuator once, using two 2x6 switches. Half of this circuit could be used verbatim as an output resistance switch.

 Such a switch suffers the "how do you describe it?!" problem, so could only be for personal use. Other people either want bass, treble controls, or no controls.


----------



## 12796

I have tried opa627, 637 and 134 in various bits of WNA kit. In every case the result left me underwhelmed. The single biggest improvement in the ongoing development of these items came when I decided to remove every single trace of burr browns products from every piece of WNA kit I owned and replaced it with National or AD. I think people like opa627 because it can be used to soften harsh sounding cd players and speakers and make it easier on the ear in an unbalanced system - but thats hardly accurate reproduction, just counteracting one fault with another.

 Nick.


----------



## PinkFloyd

.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Are there any output impedance experts in the house? Some manufacturers swear by zero ohm output impedance whilst others insist on 120ohm as per IEC 61938 international standards. What would be the best "catchall" value to use? (cause less offence to a wide range of headphones) I notice that quite a lot of the commercial manufacturers go with 120 ohm output impedance whereas the majority of DIY'ers prefer as close to zero as is possible output impedance...... What output impedance would make the amp more "bullet proof" with all headphones....... zero ohm or 120ohm (I don't mean which OI will sound better but which output impedance is the most "stable" with all headphone impedances?)_

 

very interesting, mike. impedance optimisations usually are dealt as some sort of individual tuning while there's no general optimum. jan meier elaborates on it as "tricks". it seems to depend on the headphones you use. some amp manufacturers include both a 0 ohm and 120 ohm out to handle a wider range of cans. the other way could be Syzygies' suggestion to make it switchable (although i'd prefer a simple 3 pole on/on-switcher over the rotary solution). 

  Quote:


  Originally Posted by *PinkFloyd* 
_Let us know your findings Udo and be sure to upload pics of the 10 Farad caps 
	

	
	
		
		

		
			



_

 






 ... you know... separate encasing full of caps... no... wouldn't do that: i thought about the 2F-way with some bypass caps.


----------



## PinkFloyd

Whoah! what a major improvement to the sound upping the quiescent current and replacing the incandescent lamp can bring about... and I mean a "very" noticeable increase in sound quality.

 The amp sounded like a bit of a weed with the 300R / 1K and LM6181, changing back to the 1K / 3.3K and LM6171 combo and upping the quiescent current by 25% (replacing R5 with 160R and R6 with 100R) has turned the amp into a real powerhouse, it's as if someone has shoehorned a V8 engine inside the enclosure.. seriously!! Turn that volume control past 11 o' clock and your eardrums will be flexing like a wired Romanian gymnast on the balance beams..... crank her up to 12 o' clock listening to Yello "The Eye" and your brain will rattle like marbles in a tin can.. awesome 
	

	
	
		
		

		
		
	


	




 R11, the incandescent lamp, is there as a form of protection but isn't necessary with the output caps fitted so it can be whipped out for even greater refinement to the sound. I tried a zero ohm link and Mr. LM6171 didn't like it too much..... I've experimented with a few values from 0R to 120R and the value that works best with the Senn HD-600 is certainly 8.5R (10R will do) bass is deeper, mids and treble have added clarity. Just to ensure the Oscillation God wasn't angered by me removing the little incandescent lamps I fired a ferrite bead onto both legs of the resistors... works a treat 
	

	
	
		
		

		
		
	


	








 R11: 8 ohm output resistor in place of the incandescent lamp

 Run, don't walk, to your nearest electronics supplier....... arm yourself with clip on heatsinks and resistors and try the above out..... I guarantee you 100% it'll blow your mind, if you think the MKll is ok the way it is you'll have an eargasm when you hear the difference a few resistor swaps can make! Make sure to heatsink the transistors to dissipate the additional heat.

 Mike.

*MK1:* MK1 owners can achieve the same by replacing R5 with 160R..... R6 with 100R and R9 with 8R


----------



## BrokenEnglish

hehe... good old mike is alive... 
	

	
	
		
		

		
		
	


	




 as far as i can see, this isn't practicable with the mkI. any ideas, mike?

 /edit: woah... sorry... you've done it already...

 /edit2: sh... only have those huge 5,6ohm 4 watts cement-packed resistors on my hands. need to order some standard metal ones. since you've upped the quiescence current already on my wna, mike, i'd only replace the lamp with a small resistor.


----------



## Alick

Quote:


 R11, the incandescent lamp, is there as a form of protection but isn't necessary with the output caps fitted 
 

Sounds like a worthwhile mod, but I'll be the pedant and point out that my understanding of the lamp's function is to protect the amp from a short circuit in the headphone cable. At audio frequencies, the output cap is a virtual short so, although the cap blocks any DC, a shorted cable will still draw significant AC current from the output stages and would probably cause some damage. I suspect you are only looking at a couple of cheap ouput transistors if the worst happens (and I've never suffered a damaged headphone cable, let alone a shorted one) so it's probably not a significant worry.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_hehe... good old mike is alive... 
	

	
	
		
		

		
		
	


	




 as far as i can see, this isn't practicable with the mkI. any ideas, mike?

 /edit: woah... sorry... you've done it already...

 /edit2: sh... only have those huge 5,6ohm 4 watts cement-packed resistors on my hands. need to order some standard metal ones. since you've upped the quiescence current already on my wna, mike, i'd only replace the lamp with a small resistor._

 

Here you go Udo, I've even pinpointed the resistors you should replace 
	

	
	
		
		

		
		
	


	








 MK1 resistors to replace

 R5 = 160ohm
 R6 = 100ohm
 R9 = 8ohm (anything from 0 ohm to 120 ohm to taste)


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Sounds like a worthwhile mod, but I'll be the pedant and point out that my understanding of the lamp's function is to protect the amp from a short circuit in the headphone cable. At audio frequencies, the output cap is a virtual short so, although the cap blocks any DC, a shorted cable will still draw significant AC current from the output stages and would probably cause some damage. I suspect you are only looking at a couple of cheap ouput transistors if the worst happens (and I've never suffered a damaged headphone cable, let alone a shorted one) so it's probably not a significant worry._

 

According to David there's no need for the incandescent lamp.... anyways, I've never (touchwood) experienced a shorted headphone cable so I'm prepared to live life in the fast lane and remove the lamp 
	

	
	
		
		

		
		
	


	




 The more I think of it the more I don't like the thought of my music travelling through a light bulb before it reaches my ears


----------



## 12796

PF - I am a little muddled by the flurry of recent activity (and amended posts 
	

	
	
		
		

		
		
	


	




 ). In summary, what is your updated assessment of the LM6171 v LM6181 now - my understanding is that it now varies according to which set of headphones you are using is that correct?

 Nick.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Here you go Udo, I've even pinpointed the resistors you should replace 
	

	
	
		
		

		
		
	


	




 MK1 resistors to replace

 R5 = 160ohm
 R6 = 100ohm
 R9 = 8ohm (anything from 0 ohm to 120 ohm to taste)_

 

you're great, mike... thanks!
 1/4w resisitors are just right, aren't they?

 /edit: i'll socket r9 to keep it adjustable to my needs...


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_PF - I am a little muddled by the flurry of recent activity (and amended posts 
	

	
	
		
		

		
		
	


	




 ). In summary, what is your updated assessment of the LM6171 v LM6181 now - my understanding is that it now varies according to which set of headphones you are using is that correct?

 Nick._

 

I shoot from the hip Nick so apologies if you're slightly muddled... if I held back judgement till the final moment then neither this thread nor the MKl thread would be here.... I kinda say it as I see it when it happens and, whatever's gone before, is history and is part and parcel of the evolution of this fine amp...... To my ears upping the quiescent current, retrofitting the LM6171 (with 1K and 3k3) and substituting the incandescent lamp with an 8R resistor has this amp sounding the best it's ever sounded (by quite some margin) 

 Mike.

 EDIT: meant to add, I'm usually very active posting... the past couple of months I've been really under the weather and my posts were few and far between... feeling better now hence my recent flurry of activity.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_you're great, mike... thanks!
 1/4w resisitors are just right, aren't they?

 /edit: i'll socket r9 to keep it adjustable to my needs..._

 

0.6W resistors are what the manual recommends.

 Good idea to socket R9, who knows maybe one day you'll buy a pair of DT-931's and you can slip a 120R into R9 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_0.6W resistors are what the manual recommends._

 

thanks again... you know, i don't have that manual nor any schematics.


----------



## 12796

I assume that for the CFB LM6181 then it is already in class A so these are not mods that will also improve its performance?

 What were the relative contibutions to the improvement from remvoing the lamp and increasing the QC?

 Nick.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I assume that for the CFB LM6181 then it is already in class A so these are not mods that will also improve its performance?

 What were the relative contibutions to the improvement from remvoing the lamp and increasing the QC?

 Nick._

 

Post 137 bags more grunt, more control, deeper bass, extra clarity. Wired Romanian Gymnast, tin of marbles, V8 etc.


----------



## 12796

Sorry I didnt make myself clear - what I meant is:

 What proportion of the improvement came from the qc increase and what proportion came from removing the lamp?

 Nick.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Sorry I didnt make myself clear - what I meant is:

 What proportion of the improvement came from the qc increase and what proportion came from removing the lamp?

 Nick._

 

QC = bags more grunt, better control, spadeloads of power.

 Lamp removal = deeper bass, more clarity.

 Retrofitting LM6171 with 1K and 3k3 = fuller sound, more body. 

 proportionally I'd say:

 LM6171 / 1K / 3k3 = 15%
 QC = 75%
 Lamp removal = 10% 

 It's really hard to quantify in percentage terms as there are a lot of variables but I would honestly say that the above 3 changes (combined) have improved the sound quality overall by maybe 20% and the sheer grunt and drive by a good 50% There's more oomph for _sure_


----------



## PinkFloyd

And it gets even better..............






 Zobel Network

 Dr. White suggested I try a Zobel Network in order to guard against hf instability so I did and it works.

 In place of the Incandescent lamp I now have a zero ohm link so the output impedance is now 0 ohms. There is no hiss when I touch the volco and whether this is due to the zero ohm link, the Zobel Network or a combination of "both" there is now even more clarity and the amp is allowing bags of detail to flow into my headphones..... I don't say things like "bags of detail" and "more clarity" lightly and I urge any other MK2 owners to try the latest tweaks in order that they can confirm what I am saying is valid and that I'm not dreaming all this!

 In addition to upping the quiescent current, retrofitting the 1K and 3k3 and LM6171 could someone also add a zobel network and fit a zero ohm link (ferrite beaded if you like) in place of the incandescent lamp and report back to confirm the major improvements that are to be gained by these tweaks (or not as your ears may conclude)

 To fit a Zobel Network you connect a 100nF capacitor and 10R resistor in series between the amp side (input side) of the output capacitor and ground. I only had one 100nF cap kicking around so I used 220nF values (works just the same)






 All the best.

 Mike.


----------



## BrokenEnglish

*adds another pair of .1µf polypropylenes to his order*... 
	

	
	
		
		

		
		
	


	




 ... dr. white always seems to have some hidden aces in his backhands... i'll try it.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_dr. white always seems to have some hidden aces in his backhands... i'll try it._

 

Yeh..... just when you thought it was safe to weld the lid down up crops another goody


----------



## PinkFloyd




----------



## 12796

Is this "euphony" you refer to actually on the recording? A studio production doesnt sound much like live music usually. Granted the OPA627 makes the music warmer and easier to listen to but is it accurate? The LM6171 may be telling you that something else is wrong further up the chain while the OPA627 covers it up. Two wrongs dont make a right. I think burr brown are popular as a lot of (or even most) systems sound too "hifi" and not enough "music" and the opa627 restores the balance (in a bailing out the basement kind of a way). In a balanced system it's true characteristics are revealed. Granted the LM6171 sounds a bit lean but the LM6181 seems to rectify that. At the risk of being flamed I might suggest that you are hearing the fundamental limitations of CD through the LM and not through the OPA. 

 Just to make sure ... you still prefer the WNA to the x-cans right? I get so confused with your posts. 

 Microsoft sucks!


----------



## PinkFloyd




----------



## 12796

Yes I do read your posts, and I have read the WNA threads in their entirety - they seem to jump and reverse all over the place hence my queries and suggestions. One minute you are saying the LM6171 gives you goosebumps, the next it doesn't, one minute the wna kicks ass, the next it doesnt... and then it does again. 
	

	
	
		
		

		
		
	


	




 It's going to be "toobs" next week I just know it 
	

	
	
		
		

		
		
	


	




 ***************
 Do you actually read my posts?

 Over a period of ONE YEAR and after a TRUCKLOAD of MODIFICATIONS to the WNA and a ****LOAD of POSTS here I have concluded that "I" like the SOUND of the OPA627....... I've LISTENED to every Opamp that can be rolled into the WNA and have finally concluded that MY EARS prefer the OPA627.

 If you favour a different chip then go roll it in and enjoy the music.... **** or get off the pot...... if you're confused by my posts you obviously haven't read them over a one year period...... I'll repeat "AFTER MANY MONTHS OF IN DEPTH EXPERIMENTATION WITH THE WNA (MKl AND MKll) I PERSONALLY PREFER THE SOUND OF THE OPA627BP"

 My opinion counts for nothing where your ears are concerned.... ears are like fingerprints, each pair are unique..... please go and use yours and form your own opinions.

 Mike.
 ***************


----------



## BrokenEnglish

those opa627 have their magic... ok... but i'm realizing that there's no universal truth, maybe no everyday solution with amps. for the more euphonic experiences i tend to jump back to the ppa (currently with opa627/637 
	

	
	
		
		

		
		
	


	




 ) and most likely would also use a different set of cans (dt440). 

 when i received your wna, mike, it revealed its analytic signature. and that's the sound i appreciate with classical and acoustical music. all modifications i'm about to do, should serve the goal, to keep that more analytical presentation but tame the over-emphasized highs and maybe strengthen the bassline a bit. 

 i've started today (a few hours ago) with upping the quiescent current (changing r5&r6). results were mainly noticeably reduced highs, while the bass got slightly more depth. right direction, but highs were tamed too much. ok... i was smoking too much this evening.. so maybe my hearing is impaired. maybe those resistors i used (1% metal, 0.6w) are of minor quality and/or need burn-in. i'll leave the amp and source playing this night and check again tomorrow. 

 furthermore i'll add the zobel network (thanks for your kind help with that, mike!) and replace the lamps with zero-ohm bridges (no ferrite perls!) tomorrow and report back.


----------



## PinkFloyd




----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_those opa627 have their magic... ok... but i'm realizing that there's no universal truth, maybe no everyday solution with amps. for the more euphonic experiences i tend to jump back to the ppa (currently with opa627/637 
	

	
	
		
		

		
		
	


	




 ) and most likely would also use a different set of cans (dt440). 

 when i received your wna, mike, it revealed its analytic signature. and that's the sound i appreciate with classical and acoustical music. all modifications i'm about to do, should serve the goal, to keep that more analytical presentation but tame the over-emphasized highs and maybe strengthen the bassline a bit. 

 i've started today (a few hours ago) with upping the quiescent current (changing r5&r6). results were mainly noticeably reduced highs, while the bass got slightly more depth. right direction, but highs were tamed too much. ok... i was smoking too much this evening.. so maybe my hearing is impaired. maybe those resistors i used (1% metal, 0.6w) are of minor quality and/or need burn-in. i'll leave the amp and source playing this night and check again tomorrow. 

 furthermore i'll add the zobel network (thanks for your kind help with that, mike!) and replace the lamps with zero-ohm bridges (no ferrite perls!) tomorrow and report back._

 

Hiya Udo,

 Upping the QC won't affect the frequency response one bit are you sure you've replaced the correct resistors???????


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Hiya Udo,

 Upping the QC won't affect the frequency response one bit are you sure you've replaced the correct resistors???????_

 

yeah, mike, i'm sure... double-tested it: 
 r5: replaced 120 ohm with 160 ohm
 r6: replaced 75 ohm with 100 ohm

 but as i said before... i'm not so sure, that my hearing is clear enough after lots of cigarettes...


----------



## PinkFloyd




----------



## BrokenEnglish

no help needed so far, thanks mike. i'll take the two additional steps you recommended above tomorrow and give the amp and my ears some time to settle in. just wanted to post some quick impressions.


----------



## 12796

Hey now come on Mr "PF" I was perfectly civil to you - no need to get the hump 
	

	
	
		
		

		
		
	


	




 I am just interested in a scientific pursuit of excellence - you should take it as a compliment I am picking your brains so often. I am sure everyone appreciates your efforts and your website!


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_yeah, mike, i'm sure... double-tested it: 
 r5: replaced 120 ohm with 160 ohm
 r6: replaced 75 ohm with 100 ohm

 but as i said before... i'm not so sure, that my hearing is clear enough after lots of cigarettes... 
	

	
	
		
		

		
		
	


	


_

 

Mistake Udo.... my apologies...... change those resistors back to 120 and 75. I think the 4 x 10R have to be reduced on the MK1 (down to 7R or thereabouts) let me quadruple check for you.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_
 but as i said before... i'm not so sure, that my hearing is clear enough after lots of cigarettes... 
	

	
	
		
		

		
			



_

 

Do you use your ears to smoke the cigarettes??


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Do you use your ears to smoke the cigarettes?? 
	

	
	
		
		

		
		
	


	


_

 






 you know, what i mean, mike... smoking impairs the blood circulation. sensational effects can be tinnitus. in some moments i think, even my frequenency perception is somewhat restricted. 
	

	
	
		
		

		
		
	


	




 should stop it, i know... 

 i'm just about doing the additional mods. will report results in the afternoon...

  Quote:


  Originally Posted by *PinkFloyd* 
_Mistake Udo.... my apologies...... change those resistors back to 120 and 75. I think the 4 x 10R have to be reduced on the MK1 (down to 7R or thereabouts) let me quadruple check for you.
 Mike._

 

oh... just saw this... ok, mike... i'll go back to the former setup. and wait for further instructions, sir...


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_

 oh... just saw this... ok, mike... i'll go back to the former setup. and wait for further instructions_

 

hmmm, IIRC it's a case of lowering the four 10R resistors... I can't find the bloomin circuit diagram so can't say if this is 100% correct..... I'll enquire further.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_hmmm, IIRC it's a case of lowering the four 10R resistors... I can't find the bloomin circuit diagram so can't say if this is 100% correct..... I'll enquire further._

 

don't mind, mike... i have no resistors <10 ohm on my hands. i'll replace some polyester caps and the lamps in the meantime. i'm also awaiting some bigger mkp input caps next week. thanks again...


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Hey now come on Mr "PF" I was perfectly civil to you - no need to get the hump 
	

	
	
		
		

		
		
	


	




 I am just interested in a scientific pursuit of excellence - you should take it as a compliment I am picking your brains so often. I am sure everyone appreciates your efforts and your website!_

 

Hi Nick,

 Apologies for my rambunctious comments toward you last night I have a tendancy to speak first and think later after consuming a few drams... I don't have the hump with you, I was out of order and I apologise most sincerely.

 As to the 627BP I like it, I like it a lot. It's completely different to the LM6171 sounding warmer (almost valve like) more laid back and easier to listen to. I still "love" what the LM6171 does but decided to try the 627 after listening to the X-can as it's lush presentation brought back fond memories.. so it was in with the 627 for a spin under the bonnet.

 I'm not being contradictory, one day loving the LM6171 and the next day hating it is being contradictory, what I am trying to do is to evaluate the amp with quite a few opamps and find the one that suits my ears the best.... I've really enjoyed the microscopic detail retrieval of the LM6171 for almost a year now and I stand by what I have always said "It's a superb sounding opamp"

 The x-can just reminded me how much I used to enjoy a warm sounding amp so I've decided to try and get the WNA to sound warm..... who knows, next month I may well revert back to my love of analytical sounding amps and if that's the case then the LM6171 will go back under the bonnet.

 That's the beauty of DIY you can tune the amp to your mood and you don't have to buy a new amp every time you feel the need for a change of presentation. The 6171 / 6181 are superb opamps if you want to hear every last nuance and minutae of a recording ... the 627 is great if you just want to let the music wash over you in a gentle warm way.. that's what I want this month and the 627 is delivering very nicely indeed.

 There are, quite literally, many opamps queuing up to get into the WNA and I'd like to maybe spend a few weeks giving them some airtime at some future point.... As I say, I've spent almost a year with the LM6171 and feel it's time to try some others.... if I don't try I'll never know what I may be missing and the LM6171 is always at hand should I want to revert back to it:





 I jest not when I say there are many opamps queuing to get into the WNA 
	

	
	
		
		

		
		
	


	








 Maybe I should charge them an admission fee.

 Anyway Nick, I trust that's explained things for you.... I just feel like a journey into the warm side.

 All the best.

 Mike.


----------



## 12796

Thats ok - I quite understand. The pursuit of sonic excellence can be a bit frustrating at times. I have been undergoing a similiar process with the WNA pre and phono for the last 12 months. Admittedly I raised the bar quite high with the commercial equipment I conpared them to but the WNA units have risen to the challenge. 

 It's a great shame that opamps seem to have such pronounced characters - none of them seem to "accurate" - the LM6181 seems to be the closest for me so far. The LM6171 just seems a bit on the thin and wiry sound. Be interested to see what you think of the LM6181 again after you get used to the OPA627! 

 Its a shame its not practical to switch between opamps according to a particular type of music. I found the OPA627 made some types of music more listenable but made others unlistenable - usually the opposite ones to the LM6171. I guess I am just looking for that opamp that malkes everything sound good - let me know if you find it in that queue!


----------



## PinkFloyd

In case anyone else ever has the urge to go warm here's the recipe:

 remove LM6171, replace with OPA627. Remove output caps, jumper over the pads with a zero ohm resistor with ferrite bead attached to one leg of the resistor. Measure DC offset to ensure it's below +/- 15mV in my amp the DC offset measured up at a very precise +1mV for each channel... plug in headphones, turn volume up and enjoy the warmth. (note) I removed the Zobel network and that weird hum returned when I touched the volume knob at 11 o' clock setting... replaced the Zobel network and no hum.





 C4 jumpered with zero ohm resistor and ferrite bead





 C4 from a different angle.

 Sound quality:

 Not as revealing, fast, exciting, dynamic or analytical as the LM6171. More laid back, warmer lush flowing bass, relaxing listen, ever so slightly euphonic in overall presentation and musical... It presents the music through rose tinted specs... very smooth and silky.... worth a listen if you have a 627 kicking about.

 All the best.

 Mike.


----------



## BrokenEnglish

mike... i also had that hum. because you're using plastic panels, maybe it'd be enough to earth the shaft of your pot?


----------



## BrokenEnglish

ok... restored r5 and r6... the highs are back.... gosh... and i'm glad, they are... 
	

	
	
		
		

		
		
	


	




 ...listening to steve reichs electric counterpoint (played by pat metheny) sounds so sweet... all overtones present... airy, well resolved.

 also packed the zobel net under the pot, replaced the lamps (r9) with zero-ohm bridges and replaced the 0,1 mks wimas in the psu-section with each .082 and .022µf mkps in parallel. i hear no differences... maybe the resolution is a bit better now, definitely no step back. 

 next weekend i'll stack some 2,2 mkps as input buffers, bypassed with little ones.


----------



## PinkFloyd

Hi Udo,

 I asked David about the QC on the MKl and I was correct after all, the 2 resistors you changed (120R and 75R) would have increased the QC.... the other way of doing it would be to replace the 4 x 10R resistors (R7,R8) with 7 or 8R resistors. Funny that it should reduce the treble Udo?


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Udo,

 I asked David about the QC on the MKl and I was correct after all, the 2 resistors you changed (120R and 75R) would have increased the QC.... the other way of doing it would be to replace the 4 x 10R resistors (R7,R8) with 7 or 8R resistors. Funny that it should reduce the treble Udo?_

 

hm... funny indeed... but it did reduce the treble. i listened to the amp (and a small sample of reference music i've chosen before for that purpose) the next morning with fresh ears and felt the same again. can't quite explain the phenomenon. maybe i'll try it again next weekend and give the amp (and my ears) more time to bed in.


----------



## PinkFloyd

Disregard this mod it wipes out the constant current diodes! Maximum of 220uF in C7!

 Please don't get angry Biovizier but I've rolled the LM6171 back in again this afternoon... as nice and warm as the OPA627 was I just couldn't live with it's chocolaty, syrupy sound. So much for going warm. 

 So it's back in with the LM6171 (I briefly tried the 6181 again but there's something about it that doesn't do it for me in the head-amp) I think I've managed to get a bit more out of the amp in terms of bass weight, detail, airier presentation and have also (I believe) added a bit of warmth to the sound whilst still getting all the benefits from the LM6171..... LM6171 with warmth let's say 
	

	
	
		
		

		
		
	


	




 How, you may ask, was this achieved...... well, quite simply really..... capacitance. I've always thought the 100uF rail splitter caps and the rest of the 100uF caps were a tad weedy so I've upped them quite considerably and it _does_ improve the sound across the board. 

 In the rail splitter I used 2200uF for C7 and 1200uF for C11 & C12. I would have used higher capacitance in C5 & C6 but was only able to cram 1000uF into C5 and 470uF into C6 in due to the lack of space (and lack of an extra couple of 1000uF caps in my cap box) on the board.

 So, the rail splitter now has 4600uF (instead of 300uF) and C5 and C6 now have a total of 1470uF (instead of 200uF) per channel.

 I'll give the caps a few days to form up and hopefully things will improve even further after a burn in period. I'm really spurred on to get every last ounce out of the WNA now!

 Mike.











 NOTE: forgot to add that I fitted an LM6181 into the rail splitter instead of an LM6171..... LM6171's fitted in IC1..... I powered the amp up and listened to the music but I could smell something funny coming from the amp..... I looked down and there was smoke billowing out of the LM6181 and it was making a noise like a bee buzzing...... I don't know if this is unique to my particular amp but I wouldn't recommend a LM6181 in the rail splitter, anything that smokes like that isn't welcome in my amp LOL.


----------



## 12796

Thats ok - I am not angry I expected it. I am reminded of the story of goldilocks and the three bears for some reason .

 I really do think that the problem here is that while the LM6171 has many of the qualities you want it is also rather lean and wiry sounding (which you dont want) and when you get fed up of that then its tempting to swing to the opposite extreme which of course swings you straight back again. I hope that the mods you have just made have long term viability and arn't just obscuring the issue rather than curing it. I guess you will update us after extended listening. 

 This is the perenial problem with hifi. Getting something that sounds excellent all around and with all types of music is nearly impossible. If you like just a specific type of music then its easy to be happy with a hifi with a particular sound even if it isnt accurate, so long as it suits that kind of music. However, if you like all types of music then you can't have any compromises in any area and that is expensive to buy and time consuming to find. I spent 6-12 months getting speakers, amps and deck sorted in this respect and I have now spent another 12 months on the pre and phono. Hopefully the end is in sight!

 I though the LM6181 is the best balance so far in the pre and phono - is there any further tweaking that could be done in your circuit to improve matters? It seems to keep much of the qualities of the LM6171 without the wiriness. In which areas would you say it doesnt match the LM6171 currently?


----------



## PinkFloyd

Hi Nick,

 I find the LM6181 leans more toward the OPA627 than it does toward the LM6171 (to my ears) It's hard to describe but (to my ears) it has less weight and doesn't sound as immediate or dynamic as the LM6171... sure, it certainly sounds good and I can appreciate why you like it but it has a tendency to sound just a little too polite to me.. where the LM6171 will be brutally revealing of a poor recording the LM6181 doesn't reveal the flaws of a recording in the same way.... Where the LM6171 will extract every ounce of detail out of a good recording the LM6181 can't dig as deep into a good recording as the LM6171 can. I see why you like the 6181 but it's trying too hard to be a jack of all trades and a master of none.... it's acceptable with all recordings but the LM6171 is exceptional with some and poor with others (especially bad recordings) I prefer the LM6171 warts and all.

 It's really hard to describe what you are hearing in words isn't it? terms like "resolution" "airy highs" "clarity" etc. etc. are just words and mean nothing unless you hear the music with your own set of ears. I know what you mean about finding the right opamp for every type of music and I fear the only realistic solution would be to have ten amplifiers, each with a different opamp on board, and you could number the amps and put little stickers on your CD's to tell you which amp to listen to the CD through.... a bit extreme maybe but I'm sure there are enthusiasts who have gone down this road. Similarly there are many head-fiers who own over 10 pairs of headphones and use each pair to listen to different types of music... again, extreme but it's the ideal solution for some people.

 Have you considered going discrete? That would negate the use of opamps and you may find you prefer the sound without an opamp in the way. Unfortunately Nick, the only way you'll find what's right for you is by listening to a wide variety of amps, sources, opamps, speakers etc. and your ears will tell you what they prefer... I gave up reading Hi-Fi mags many years ago after coming to the conclusion that the reviewers were either deaf or taking backhanders.. I was always coming home with the "best buys" and award winners and I don't think there was once that I liked the sound of any of them... it was only after I built my first pair of Wilmslow audio speakers that I realised the beauty of DIY.. you can tune the sound to your own tastes and don't have to accept premade equipment and endure sound that doesn't suit your taste.

 Sometimes you'll strike it lucky and stumble upon a piece of equipment which blows you away but those instances are few and far between unfortunately... 9 times out of ten you have to accept a compromise and it's very rare to find a system that is all singing and all dancing and does everything right and searching for it may lead you to forget the meaning and the message of the music... there comes a time when you are listening to the system and not the music, I've been down that road and it's not a good place to be... you're never satisfied and there's always something "not quite right" about the sound... you forget how to relax and enjoy the music.

 Some of the most memorable, enjoyable moments of my life were spent at rock concerts listening to seriously distorted sound in acoustically crap venues but that didn't stop me from enjoying the event.. I wasn't commenting about the colouration or the distortion or the standing waves in the venue.... hell no I was enjoying the music! There comes a time when you've got to say enough is enough and just lay back and let the music wash over you.. grab a few beers and stick a live Floyd concert on and crank that volume knob clockwise!!!

 Enjoy the music.

 Mike.


----------



## 12796

Indeed - the reviewers are taking backhanders from L**n, N**m to name but a few - I had a friend in the trade and it's an open secret the whole industry is crooked. At one industry dinner meeting the lead speaker toasted the very reasonable rates of bribeability of the english hifi press! Fortunately I never trusted the mags and always did my own thing so I didn't ever get landed with any real clunkers thats the mags recommended. I used my own ears and told the dealer exactly what I thought - which led to a few arguments especially with L**n dealers when I told them their turntable was junk. 
	

	
	
		
		

		
		
	


	




 I found the turntable aspect to be the worst - arm, deck and cartridge have to be combined and all interact with no hope of any kind of scientific comparison from shop to shop, or even that the decks were setup properly. Even when shops were prepared to swap arms and cartidges it often exchanged one set of compromises for another. Eventually I found a combination that did everything well and had no weak points at all (Brinkmann) - but I had to listen to virtually every deck on the market and had to pay much more than I orginally budgeted for. Choosing speakers was only marginally easier. I dislike almost every speaker ever made due to their colourations and tonal neutrality but fortunately I came accross PMC and Bryston and they seemed to play any kind of music pretty well. Which just left me to sort out the preamp and phono. I orginally approached WNA to build the pre as I had special requirments (driving 6 channels balanced tri-amped) that a normal pre wldnt meet. Having been pleased with the result I then commisioned a WNA phono to replace The Groove. Though on balance the WNA beat the groove even at the start, each had its own areas of strenth and it took 9 months of development to get to the point where it beat the groove all around - and there are still a couple rounds of mods to go 
	

	
	
		
		

		
		
	


	




. Then next up is the headamp and 6 channels of WNA power amplification!

 I suspect the LM6181 will have to be the compromise for me - at least until the custom built "composite opamp" can take it's place. That unit might very well be comprised of discrete components. Part of the imediacy and impact of the LM6171 is due to its leaness. Tonally it accentuates the bass and the treble - the same trick that the sondek pulls. 

 1UP will be bringing around his headamp in the next few weeks when the latest round of mods are complete so I hope to do a more direct comparison of the two chips and the headamp at that time.

 I am a live music fan too - I agree totally with your comments. 

 Nick


----------



## PinkFloyd

Hi Nick,

 I've spent the last couple of hours listening to some of those opamps I've been threatening to try for the past year and there's one which I think you'll like a _lot_ The AD843.

 I had a quick listen to it a while back with the circuit optimised for the LM6181 and commented to David that it sounded really promising but you had to crank the amp up to the 3 o' clock position on the volco to get a half decent volume so I didn't pursue it further until now.

 The resistors which were used to optimise the LM6181 have been replaced with the ones used with the LM6171 (LM6181 sounds a lot better with the original resistor values too by the way) so I tried the AD843 to see if this made any difference to it..... just a bit!

 You know what Nick, this is a very nice sounding opamp in all departments.... the same speed, seperation and detail retrieval (more actually) as the LM6171 but without the slightly clinical presentation... the bass is superbly presented (and I mean first class) listening to the bassline on "shpongle falls" from the "are you shpongled album" it was hard to pinpoint exactly what was going down listening with the LM6171.. it sounded like a vroom vroom mooo, vroom vroom mooo..... very hard to follow the bassline and even harder trying to work out what the damned instrument was.... with the AD843 it was bye bye splurge boom and hello tight bass....... very easy to follow the bassline and it actually sounds like a bass guitar and not some weird sloshy subterranean sound effect like it does with the LM6171.

 I'll stick with this album as I know it backwards (or at least I thought I did until I rolled the AD843 in) You thought the LM6181 / 6171 were great at detail retrieval well the AD843 allows a lot more detail through compared to them..... track 2 "monster hit" was simply awash with new found goodies in the mix.. subtle, but pronounced enough to cause me to turn my head round thinking it was something in the room that was causing this newly found detail..... and again, the bass...... tight, easy to follow and extremely musical.

 Track 3 "Vapour rumours" (on the phenomenon of unidentified flying objects) Hell I always wondered what the guy was saying... there's a lot of speech in the first part of the track and it's pretty hard to make some of it out with the LM6171....... with the AD843 you can make "every" last word out... "on the phenomenon of flying objects"... ah and there's me been thinking they were saying "on the fire farm or frying objects" for the past year (seriously) the detail and clarity the AD843 delivers is astonishingly good.

 Track 4 "shpongle spores" This track has never sounded this way to me before... everything is presented in it's own little space in time with the rest of the instruments but encapsulated in little air bubbles that you can home in on and follow..... (no, I don't smoke drugs) talk about seperation and easy to follow each individual instrument... the LM6171 sounds positively congested compared to the AD843.... again, the bass is so so tight, musical and start / stops are followed by an inky black silence... not a trace of overhang.

 Track 5 "Behind closed eyelids" Again... full of hidden surprises the LM6171 never found.... the textures of the sound seem laid on a much more musically involved canvass.... the detail is there, the seperation is there but it's not laid out in parts on a canvass like the LM6171.... with the AD843 you're first presented with the music as a whole and you can then explore each element which makes up the whole at your leisure..... you're not force fed with data with the AD843..... it presents the music and the emotion first but will allow you insight into the elements that make the whole should you desire to home in on any one component of the performance.

 Track 6 "Divine moments of truth" First impressions listening to this track were "beautiful tuneful bass" The LM6171 just cannot present bass like the AD843.... no way. Sure, it goes as deep with the LM6171 but it's nowhere near as realistic, tight or tuneful as the AD843. Yet again, the detail retrieval is absolutely breathtaking and the seperation of instruments is the best I have yet experienced from any op amp...... it's analytical if you want it to be, it's tight and fast in the bass, it excites, it makes music and it captivates your senses..... parts of this track were seriously out of your head... some elements of the music are thrown a good 6 inches out of your head (LR) and the height, width and depth of the soundstage are far better than what the LM6171 can muster up.

 Track 7 "and the day turned into night" how apt a title for a track considering what I'm about to say.... The AD843 makes music sound like music and appears to be a very rare breed of opamp which does everything well.... This is probably my favourite track on the album and I have never heard it sound so textured, so right, so "fresh", so "new" I've been listening to this track over and over again over the years and am astonished to, finally, hear it presented in such a graphically revealing, musical and emotionally stirring way.... I'm gobsmacked by this opamps ability to make music sound like music... I'll be pulling out every CD from my collection to listen to them with this beauty at the helm of the engine.

 This was the last opamp I'd have rolled in if the "spec sheets" were anything to go by but it turns out it absolutely trounces the LM6171 in every respect...... the extra capacitance I added to the WNA this morning "may" have something to do with it but I doubt it.... the LM6171 based amp with added capacitance sounded better than it did with the standard 100uF caps in place but the AD843 sounds "considerably" better than the LM6171 in the same setting.... 

 I'm so glad you and the Chinese amp spurred me on to get active under the WNA bonnet Nick... I think you'll be _very_ impressed with the AD843 and I hope Dr. White will have a good listen to it along with the capacitance mod. I "will not" be reporting back tommorow that I've retrofitted the LM6171 or have "gone warm" with the OPA627....... I have these intense phases from time to time where I seemingly chop and change and alter my opinion on a daily basis....... I call it experimentation but I can fully appreciate how others may see it as inconsistency..... 

 I'll send my findings to David (my hearings should that be?) and look forward to his comments on the extra capacitance and AD843... As it stands (to my ears) these mods have been worthwhile and very productive indeed.

 I promise you Nick, I won't be changing my mind on this one..... my period of intensive activity with the WNA has reached the desired goal to my ears..... I've explored every avenue and the AD-843 is a keeper. 

 Mike.


----------



## BrokenEnglish

very interesting, mike. the ad843 became a sort of secret tip over the last few months. people like tangent and ppl seem to like them a lot and i know at least one diyer who stopped immediately looking for any alternatives and fitted them in the whole line of pimetas, ppas and m³ he built. they're on my list as ad8610-replacement for the ppa, so i'll also try them with the wna. where did you get yours, mike?


----------



## 12796

Cool! I can't wait to see where further experimentation leads. Shame it's too noisy for the MC stage of the phono. 

 Does anyone have any experience of the AD8000?


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Cool! I can't wait to see where further experimentation leads. Shame it's too noisy for the MC stage of the phono. 

 Does anyone have any experience of the AD8000?_

 

crap I keep forgetting you don't have a WNA headphone amp... sorry man.... when you say the AD-843 is too noisy for your Moving Coil stage could you elaborate? I've been "power rolling" opamps into the head-amp to find a good one for you / me / us and found an absolute gem of an opamp (AD843)

 And now you tell me it's no good for use in the Moving coil stage of your phono amp......... 
	

	
	
		
		

		
			





 ...... Have you tried one of the Graham Slee phono stages? I think you've got the wrong thread Nick........ this is "WNA MKll" headphone amp and not "What's the best opamp for use in my phono stage" thread.

 With respect, I think you need to ask your questions elsewhere (maybe in the source forum?)....... they are not relevant to this thread and I (for one) can't help you when it comes to phono stages.

 All the best.

 Mike.


----------



## 12796

Hi,

 Sorry, the phono comment was an aside - I will ask about low noise opamps elsewhere. 
	

	
	
		
		

		
		
	


	




. I previously had a Groove - grahem slee is a step back. 

 The ad843 is suitable for the rest of my WNA kit - your effort has not been wasted dont worry! I shouldn't have muddied the waters by commenting on the mc issue - thats something that doesnt concern this thread, I was just browsing the AD8000 at the same time as the ad843 on the AD website. My bad. 

 Nick.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Hi,

 Sorry, the phono comment was an aside - I will ask about low noise opamps elsewhere. 
	

	
	
		
		

		
		
	


	




. I previously had a Groove - grahem slee is a step back. 

 The ad843 is suitable for the rest of my WNA kit - your effort has not been wasted dont worry! I shouldn't have muddied the waters by commenting on the mc issue - thats something that doesnt concern this thread, I was just browsing the AD8000 at the same time as the ad843 on the AD website. My bad. 

 Nick._

 

Talk about being confused!


----------



## Madcat05

Has anyone put together a parts list for the WNA MKII? I'm interested in what it would cost me to source parts for the amp. Thanks!


----------



## 12796

Confused? Revenge is sweet


----------



## BrokenEnglish

Quote:


  Originally Posted by *Madcat05* 
_Has anyone put together a parts list for the WNA MKII? I'm interested in what it would cost me to source parts for the amp. Thanks!_

 

get the kit, madcat05 - it includes everything that you'll need (incl. wire, case, solder). the price is gbp 150, if i'm right.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Confused? Revenge is sweet 
	

	
	
		
		

		
		
	


	


_

 

Revenge expends the same amount of negative energy used in a search for the holy Grail...... pointless waste of time and energy IMO

 Enjoy the music.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_get the kit, madcat05 - it includes everything that you'll need (incl. wire, case, solder). the price is gbp 150, if i'm right._

 

Wait a bit and see if Dr. White tries the AD843 and extra capacitance... it would be good to learn his opinion on this one.

 Mike.


----------



## BrokenEnglish

btw... i'm quite curious if an increased voltage will improve particular the bass response with the lm6171. with some more complex arranged recordings i get the feeling that the bass "jumps away", as soon as other frquencies get crowded. hm... i have the psu, but was not able to install the bigger transformer because i'd need some tools for the casework, that did not arrive. note that the meier amps use +/-15v...


----------



## Madcat05

Well I'm not planning on building this amp untill maybe the summer. So I'll wait and see what the kit is like then. Thanks


----------



## raja

Hi,

 I too found that with solid state stuff, when tweaking and using componenets that are faster etc, you get to a point where everything gets way too clinical. Initially you are overwhelmed by the extra detail and nuances. But the effect although continually surprising, causes you to listen for individual sounds, and eventually you stop listening to 'music'. In my output stage/head amp I have resorted to tantalum resistors in the signal path. I never did try this with the wna though. 

 The tantalum resistors introduce second harmonic into the sound, you get thickening of the mid band, roll-off in the highs and the bass becomes more tuneful. I found this to be the best compromise. Though I must confess I have never tried carbon type resistors instead.


 Thanks
 Raja


----------



## 12796

Given the ad843 sounds so good but the specs arent amazing - what is it that is responsible for the outstanding results? What aprt of the architecture is it due to? Can either you or Dr White hazard a guess?


----------



## Alick

This is fascinating. I know as well as anyone that spec's can be of secondary importance when it comes to subjective audio considerations, but on paper (I've just had a _very_ quick look), the AD843 looks like it should be a non-runner in this company. Bandwidth aside (6171, 6181 and 843 should have more than enough bandwidth to cope with the most demanding audio application), the slew rate of the AD 843 is much (up to ten times) slower the other two and the settling time is almost three times slower too. I can imagine circumstances where this might sound better, but not in the revealing, detailed way that Mike has described. I'm not doubting that it is better as I've backed enough of Mike's mod-horses without being disappointed to trust his opinion, but I'm very curious to know why it does what it appears to do. I notice Farnell carry the AD843 at just over six quid a pop; I feel an order coming on ...


----------



## 12796

The secret must lie in the topology of its construction and operation - look at how it differs from all the other chips and you will likely find the answer  

 Solid state isnt my forte - any guesses anyone?


----------



## 12796

And if we can figure out what it is then the next question is ... what other chips operate the same way and will PF have a nervous breakdown when we suggest some others to join his silicon queue?


----------



## 12796

Alick,

 I find this area fascinating too. I posted something on this topic previously. 

http://www6.head-fi.org/forums/showp...7&postcount=74

 I look forward to someone taking advantage of this opportunity and furthering our collective knowledge considerably. 

 Nick.


----------



## raja

I think the internal feedback used by the opamp has something to do with the final presentation, high levels of feedback usually result in over tight bass and in your face detail. Somehow the way the air and emotional content is presented becomes less 'engaging'. The ad843 probably uses a lot less feedback than the other opamps mentioned.

 Thnaks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_And if we can figure out what it is then the next question is ... what other chips operate the same way and will PF have a nervous breakdown when we suggest some others to join his silicon queue? _

 

I note tangent has added the AD843 to his opamp page

 More opinions of the AD843 here


----------



## PinkFloyd

I measured the temperature of the AD-843 and it's quite warm in operation (59C) It's probably ok to run it naked given the AD843JN is rated over the commercial temperature range of 0°C to +70°C but it may run hotter in very warm climates in which case it's probably advisable to heatsink it to dissipate some of the heat.






 Warm chip

 The MKll is quite the mini heater what with the 843's punting out 59C and the eight transistors each punting out 80C totally different from the Mk1 which ran as cool as a cucumber.. there again I have upped the quiescent current which put an extra 20C onto the transistors (60C with standard QC) may be worth adding a mini fan in the summer 
	

	
	
		
		

		
		
	


	




 AD-843 is still sounding very nice after spending 24 hours cooking away inside the amp... it is, for sure, a very good alternative to the LM6171 / LM6181 / OPA 627 / AD8065 ... it's got elements of each of these opamps good points and it doesn't offend in any department.... I think that's why I like the sound, it's accurate, warm, analytical and musical all in the one package.

 Sure, it doesn't boast enormous slew rates or possess rapid settling time stats... so what, it makes good music and that's all that matters.... as I said before just because something boasts good specifications on paper doesn't mean it will necessarily sound good..... Jimi Hendrix couldn't be classed as technically perfect (in the classical sense) but, man, he could fire out a bloody good tune..... seemingly the same with opamps, there will always be one seemingly run of the mill (on paper) opamp that will break the rules of convention and kick you up the bum with its music making genius...... The AD843 is the Jimi Hendrix of the opamp world


----------



## StevieDvd

Are there any drop-in opamp replacements for the WNA mark 1 which don't need caps or resistors changing?

 Not that I am unhappy with the amp as is, but some simple opamp rolling can be fun as well. 

 Have LM6171 fitted to all three sockets.


 Steve


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_I measured the temperature of the AD-843 and it's quite warm in operation (59C) It's probably ok to run it naked given the AD843JN is rated over the commercial temperature range of 0°C to +70°C but it may run hotter in very warm climates in which case it's probably advisable to heatsink it to dissipate some of the heat._

 

mike.. if i understood you right, you're driving the ad843 with that recently increased quiescence current, thought for the lm6171? no further modifications? hope i can jump in with my own experiences next week...


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Are there any drop-in opamp replacements for the WNA mark 1 which don't need caps or resistors changing?

 Not that I am unhappy with the amp as is, but some simple opamp rolling can be fun as well. 

 Have LM6171 fitted to all three sockets.


 Steve_

 

Ok, let me think......... yes!

 stick something like an opa 134 or TLO71 or OPA627 in the rail splitter (IC2) (don't use a LM6171 in this position if you are dispensing with the output caps)

 In IC1 you can roll the following in safely without the output caps in circuit (check DC offset before plugging headphones in) You can also use these with the output caps in place and there's no need to check DC offset if your keeping the output caps..... these are direct roll in alternatives:

 OPA627

 OPA134 

 AD8605 (you'll need a browndog adapter)

 AD8610 (you'll need a browndog adapter)

 AD843

 AD825

 LM6181 (requires output caps in place like the LM6171)

 There are more but I haven't got round to trying them in the WNA yet Steve..... from the above list the top three (IMO) are AD 843, OPA627 and AD8605.... they are direct drop in replacements and can be used without output caps (check DC offset) or with output caps.

 Now that spring has sprung I'll be evaluating many other opamps and will upload a new, revised, more comprehensive opamp section to my website.... The "chiarra" opamp review I uploaded a few years ago needs serious updating and, looking at it now, I can't believe it was me who wrote all this stuff!  That needs updated and fast!!


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_mike.. if i understood you right, you're driving the ad843 with that recently increased quiescence current, thought for the lm6171? no further modifications? hope i can jump in with my own experiences next week..._

 

Roll the 843 in no problems Udo..... I've got it running "with" output caps, I haven't yet got around to removing the output caps and measuring the offset.... sounds good with output caps so can (theoretically) sound even better with them 
	

	
	
		
		

		
		
	


	




 I'll try them without output caps at the weekend.

 Mike.


----------



## StevieDvd

Thanks,

 I have output caps in place (1000uf Nitai's) I'll see what opamps my usual suppliers have.



 Steve


----------



## 12796

Raja - what is the mechanism by which too much feedback is detrimental? I did see a good rationale a while ago but I completely forgot what it was 
	

	
	
		
		

		
		
	


	




 PF - are there any particularly good opamp heatsinks?


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_PF - are there any particularly good opamp heatsinks?_

 

Yes...... your tongue springs to mind 
	

	
	
		
		

		
		
	


	




 (this is an attempt at a joke btw 
	

	
	
		
		

		
		
	


	




 )

 WNA supply good little dil8 heatsinks.


----------



## BrokenEnglish

ad843-datasheet:
 "USING A HEAT SINK
 The AD843 consumes less quiescent power than most precision
 high speed amplifiers and is specified to operate without using a
 heat sink. However, when driving low impedance loads, the current
 applied to the load can be 4 to 5 times greater than the quiescent
 current. This will produce a noticeable temperature rise,
 which will increase input bias currents. The use of a small heat
 sink, such as the Mouser Electronics #33HS008 is recommended."


----------



## 12796

"Coolermaster" anyone?


----------



## BrokenEnglish

Quote:


  Originally Posted by *biovizier* 
_"Coolermaster" anyone?_

 

not that bad at all... those ram-coolers, overclockers use for the chips on their memory modules or on their video cards would be just fine. you'd need to thermo-glue them.


----------



## odaen

Make sure to get some Arctic Silver, maybe install a water cooling block with some neon lights. Quite possibly it might be an idea to replace your entire case to help cool it down. I hear liquid nitrogen works wonders!


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_ad843-datasheet:
 "USING A HEAT SINK
 The AD843 consumes less quiescent power than most precision
 high speed amplifiers and is specified to operate without using a
 heat sink. However, when driving low impedance loads, the current
 applied to the load can be 4 to 5 times greater than the quiescent
 current. This will produce a noticeable temperature rise,
 which will increase input bias currents. The use of a small heat
 sink, such as the Mouser Electronics #33HS008 is recommended."_

 

Thanks Udo


----------



## PinkFloyd

Quote:


  Originally Posted by *odaen* 
_Make sure to get some Arctic Silver, maybe install a water cooling block with some neon lights. Quite possibly it might be an idea to replace your entire case to help cool it down. I hear liquid nitrogen works wonders!_

 


 We're talking a paltry 60C (MAX) here odaen...... they are probably best left naked but in countries with a high ambient temperature it's probably wise to to sink them to dissipate the heat.


----------



## BrokenEnglish

hm... the datasheet also recommends additional power cap bypassing of pins 4 and 7 with each one 2.2µf tant and .1µf ceramic in parallel. any ideas where to locate these? mike... your part..


----------



## PinkFloyd

Just received this from Dr. White and he said I could quote verbatim so here goes:

 "Mike,
 Thanks, I'll be interested to give it a whirl. I've been looking at the AD843 datasheet. Its open loop gain is "only" 30,000 which is low for an opamp. So it qualifies as a low feedback opamp. It also has a very high quiescent current of 12mA which means that the output stage runs in class A. Low feedback class A amps generally have low transient intermodulation distortion ( TIM ) and will sound warm. Quite a few popular power and headphone amp designs are wedded to the low TIM philosophy, which originated with Otala if I'm not mistaken. Given that the AD843 output stage already runs in class A you can reverse the class A mods to the WNA, which were intended to bias the LM6171 output stage into class A, if you intend to stick with the AD843. It doesn't do any harm but will increase the dissipation in the AD843 unnecessarily ( but only by a small amount )


 Regards, David"


 <Off to reverse the Class A mods as we speak>


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_hm... the datasheet also recommends additional power cap bypassing of pins 4 and 7 with each one 2.2µf tant and .1µf ceramic in parallel. any ideas where to locate these? mike... your part.. 
	

	
	
		
		

		
		
	


	


_

 

Give me 24 hours Udo........ I'm more than happy with 843 as a roll in........ it appears even more performance can be extracted from it.............

 Mike.


----------



## BrokenEnglish

take your time, mike... i'm indeed convinced, there's some additional potential... good luck!


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_hm... the datasheet also recommends additional power cap bypassing of pins 4 and 7 with each one 2.2µf tant and .1µf ceramic in parallel. any ideas where to locate these? mike... your part.. 
	

	
	
		
		

		
		
	


	


_

 

Tantalum Bead 10p each

Ceramic Disc 6p each


----------



## 12796

Be interesting to see where this leads if Dr White can make any more improvements!

 RAM coolers sounds like the best bet. Any recomendations for the best types? How much are they?


----------



## BrokenEnglish

Quote:


  Originally Posted by *biovizier* 
_Be interesting to see where this leads if Dr White can make any more improvements!

 RAM coolers sounds like the best bet. Any recomendations for the best types? How much are they?_

 

well... there are those xtra-large (-high) revoltec ones, for example:




 maybe a bit overkill + you'd pay some unnecessary extra-bucks for styling and and image. 

 i'd go with regular ic-coolers like the one on the right:




 cut them to the right length and you're done. don't forget some sort of thermoconductive glue or adhesive pads.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Tantalum Bead 10p each

Ceramic Disc 6p each_

 

yeah... easiest way to go is to solder them directly to the pins. though... i'm not quite sure where to get the necessary grounding - additional wire?


----------



## PinkFloyd

I've got a few lumps of 8mm aluminium kicking about and will start with fixing 2 aluminium pads attached to the top of the opamps and then attach something across the span of the 2 chips (fixed onto the aluminium pads on top of the opamps) I've got the pads in place and have notched them so that it's easy to observe correct orientation when refitting the opamps.... finished the pads off with 1200 grade sandpaper and polished up with brasso:


----------



## BrokenEnglish

sorry for ot... but could someone please provide me with the markings of the two transistors in the voltage divider section of the mkI (would have to desolder mine because at least one of them is nearly touched by the bigger mkps i placed in front)? they got really hot this morning (during break-in) and seem to be a litte deranged. would like to be prepared for servicing it, if necessary. thanks!

 ah... mike... for cooling purposes rau sufaces are superior. some of my oc-friends even started to sandblast their cpu-coolers... 
	

	
	
		
		

		
		
	


	




 . that aluminium is 8mm thick? you could simply drill some holes in (without breaking through) to increase surface and therefore lower thermal resistance. nice fit!


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_sorry for ot... but could someone please provide me with the markings of the two transistors in the voltage divider section of the mkI (would have to desolder mine because at least one of them is nearly touched by the bigger mkps i placed in front)? they got really hot this morning (during break-in) and seem to be a litte deranged. would like to be prepared for servicing it, if necessary. thanks!

 ah... mike... for cooling purposes rau sufaces are superior. some of my oc-friends even started to sandblast their cpu-coolers... 
	

	
	
		
		

		
			





 . that aluminium is 8mm thick? you could simply drill some holes in (without breaking through) to increase surface and therefore lower thermal resistance. nice fit!_

 

Hi Udo,

 TR3 is BD139
 TR4 is BD140


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Udo,

 TR3 is BD139
 TR4 is BD140_

 

thanks, mike... i'll be prepared then...


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_thanks, mike... i'll be prepared then..._

 

Why are they running hot? they should be as cool as cucumbers. I measured their core temperature and it's only 29C.


----------



## BrokenEnglish

to be honest, i don't have a clue... 
	

	
	
		
		

		
		
	


	



 i switched to an other psu this morning and felt that heat short time after. of course i instantly de-connected the psu. beside that "incidence" they were quite cool and are cool now again. will check that particular psu in detail some times later. although... a bad feeling remained... i feel the urge to touch those bd139/140 every few minutes....


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_to be honest, i don't have a clue... 
	

	
	
		
		

		
		
	


	



 i switched to an other psu this morning and felt that heat short time after. of course i instantly de-connected the psu. beside that "incidence" they were quite cool and are cool now again. will check that particular psu in detail some times later. although... a bad feeling remained... i feel the urge to touch those bd139/140 every few minutes.... 
	

	
	
		
		

		
		
	


	


_

 

Don't worry Udo I had many visits from the oscillation god and, on occasions, the transistors became red hot (a fast way to burn them in and a good way to burn the end of your finger if you use it as a probe to find where the heat's coming from 
	

	
	
		
		

		
		
	


	




) as long as they're still working all will be well.... the smoking buzzing LM6181 still works! I remember once connecting the Chiarra PSU up incorrectly... I plugged it in and BANG! one of the resistors exploded and shot off the PCB like a speeding bullet 
	

	
	
		
		

		
		
	


	




 What regulator is being used in the PSU? (the PSU that caused TR3 and TR4 to heat up)


----------



## BrokenEnglish

it was my first lm317-build, adjusted to deliver exactly 24,3v. and that's what i measure now. cabling seems to be ok, too. also i don't hear differences since that incident.

 as a sidenote: the bass of my mkI developed a bit after my weekend mods (replacing power caps bypassing, lamps, installing the zobel). but it is also slightly muddied, the way i know it as half-way burned in. i'm still a big lm6171 believer and wait every day for some parts to arrive, so that i'll be able to alter input capacitance and voltage. i'll also try another time to increase qc (per r5/r6).


----------



## rjackaman

After reading browsing this thread since the start I finally took the plunge and ordered the MkII kit from Dr White last week. Got one complete with Hammond case and pcb mounted pot and phone socket. As I haven't assembled anything like this for more years than I care to admit, it was a bit daunting to start with. 

 To cut to the chase, two evenings later assembly was complete. Did have a bit of a problem resulting in no sound from the right channel. Thinking that this was something on the board that I'd shorted I spent a good couple of hours checking joints and testing various things only to eventually notice that the signal wire had come off the input phono...duh!!

 The sense of achievement in getting it all up and running is amazing. To be finally sitting here listening to music on some equipment that I built is great. I think a big part of that is how well designed the kit is. Fairly straightforward to assemble...a testiment to the good Dr White.

 I'd also like to thank all the contributers to this thread for all the information that finally made me want to embark on this project.

 On the sound front it's nothing short of amazing, very spacious soundstaging, solid bass and it's not even run in yet. 

 For anybody else thinking of building the amp all I can say is "go do it, you won't be disappointed."

 Now I can mod it!!

 Cheers 

 Richard


----------



## raja

biovizier said:
			
		

> Raja - what is the mechanism by which too much feedback is detrimental? I did see a good rationale a while ago but I completely forgot what it was
> 
> 
> 
> ...


----------



## 12796

I would like to get the scientific and abstract to converge - that would be the best possible solution!


----------



## raja

Quote:


  Originally Posted by *biovizier* 
_I would like to get the scientific and abstract to converge - that would be the best possible solution!_

 


 A bit like trying to find the matter within the anti matter? Good luck!!!


----------



## 12796

All the antimatter is missing didnt you know?

 still some particles can spontaneously oscillate between matter and antimatter so maybe its possible 
	

	
	
		
		

		
		
	


	




 you just cant have both at the same time due to pauli exclusion principle and you cant be absolutely sure which is which coz of heisenberg


----------



## raja

precisley my point


----------



## 12796

I was running with it - I knew what you meant 
	

	
	
		
		

		
		
	


	




 But still I wont give up!


----------



## raja

that's akay 'brudda' we all have our part to play in the fabric of things..........

 If I were to build the wna again, I'd use tantalum resistors in the feedback loop, PIO for power and output caps, now ain't that illogical...........

 Good luck!

 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *rjackaman* 
_After reading browsing this thread since the start I finally took the plunge and ordered the MkII kit from Dr White last week. Got one complete with Hammond case and pcb mounted pot and phone socket. As I haven't assembled anything like this for more years than I care to admit, it was a bit daunting to start with. 

 To cut to the chase, two evenings later assembly was complete. Did have a bit of a problem resulting in no sound from the right channel. Thinking that this was something on the board that I'd shorted I spent a good couple of hours checking joints and testing various things only to eventually notice that the signal wire had come off the input phono...duh!!

 The sense of achievement in getting it all up and running is amazing. To be finally sitting here listening to music on some equipment that I built is great. I think a big part of that is how well designed the kit is. Fairly straightforward to assemble...a testiment to the good Dr White.

 I'd also like to thank all the contributers to this thread for all the information that finally made me want to embark on this project.

 On the sound front it's nothing short of amazing, very spacious soundstaging, solid bass and it's not even run in yet. 

 For anybody else thinking of building the amp all I can say is "go do it, you won't be disappointed."

 Now I can mod it!!

 Cheers 

 Richard_

 

Hi Richard,

 Welcome to Head-Fi! Glad you like the WNA 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


----------



## bludragon

Well, seems like rjackaman got in there before me, but I too figured I'd order one last Friday. Got the kit by Wednesday, and three evenings and a 1hr search in the loft for that elusive 6.5mm to 3.5mm headphone jack adaptor I was listening to some very nice sounding music.

 Although I was pretty nervous when I first powered it up, it all worked 1st time.

 Seems to sound pretty good too, though I've never heard any decent headphone amps to compare it too, it does pretty well v.s. my normal amp and speakers, and is very likely almost completely limited by my cd player and headphones. 

 In terms of tinkering with it, I was thinking I should get rid of those output bulbs as I was soldering them in, and also wondering if the psu wire shouldn't be a little meatier, and I could add some caps...

 With regards to op-amp selection, what do people think of one's specifically marketed as hi performace audio types, eg the AD797? I always assumed they'd be amoung the best.


----------



## BrokenEnglish

Quote:


  Originally Posted by *bludragon* 
_With regards to op-amp selection, what do people think of one's specifically marketed as hi performace audio types, eg the AD797? I always assumed they'd be amoung the best._

 

dr. white and pinkfloyd tested lots of different opamps in the wna ha mkI. it's all 
 documented at great length in its own thread. at the end, the lm6171 was a winner (with the ad843 being currently in discussion) with the mkI, while the mkII was constructed based on the experiences with the mkI.


----------



## 12796

The ad797 is pretty good - but not as good as the LM6181, I have done a comparison in my WNA kit. The latter sounds better all round.

 Nick.


----------



## PinkFloyd

Quote:


  Originally Posted by *bludragon* 
_With regards to op-amp selection, what do people think of one's specifically marketed as hi performace audio types, eg the AD797? I always assumed they'd be amoung the best._

 

Hi Bludragon,

 Nobody can tell you that one opamp sounds better than another, only your own ears can be the final judge... one person may hate the LM6181 whilst another may love it, one person may swear by Black gate capacitors others may swear _at_ them.... use your ears and try as many opamps as you can to find which one is right for you.

 Good ones to try in the WNA are:

 AD8065
 AD8610
 AD797
 AD843
 AD811
 AD825
 OPA627
 LM6181

 Welcome to Head-Fi!

 All the best.

 Mike.


----------



## 12796

Indeed - you might reach a very different conclusion! Happy hunting!


----------



## Alick

Over the past couple of weeks, I've been playing with variations of the latest set of Mod's Mike detailed earlier in this thread. I removed the lamps, replaced them with links, added the Zobel networks (they fit quite neatly under the PCB) and changed the resistors which determine the QC. I haven't change R2 or R3 (yet). I initially left the LM6181 in situ so I could compare the sound with the op-amp I'd last listened to before the changes were made. 

 I was disappointed. I couldn't quite put my finger on why, but the sound was not as detailed, lively or musical as it had been. However, when I replaced the LM6181 with the LM6171 (a week later), the life and sparkle came back to my music. I want to try the LM6181 again this weekend to make sure that my hearing wasn't impaired by a cold I thought I was over. That said, I'm inclined to believe that the mod's (maybe the QC mod in particular?) favour the LM6171 more than the LM6181 which I suspect sounds better unmodified. 

 The plan for this weekend is to try the LM6181 again, then change R2 and R3 and see how it sounds with both op-amps. I'll report back.

 Mike; how are the AD843s burning in?

 EDIT: I meant to mention above that the lower frequency response and detail after the QC mod is stunning. It's quite unlike any headphone amp I've heard before.


----------



## bludragon

Thanks for the suggestions, I'm thinking to really tweek this thing objectively I'd need a second one so I could blindly swap between configurations.

 I'll probably stick with the LM6171 for now and maybe try some of the other mods.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Over the past couple of weeks, I've been playing with variations of the latest set of Mod's Mike detailed earlier in this thread. I removed the lamps, replaced them with links, added the Zobel networks (they fit quite neatly under the PCB) and changed the resistors which determine the QC. I haven't change R2 or R3 (yet). I initially left the LM6181 in situ so I could compare the sound with the op-amp I'd last listened to before the changes were made. 

 I was disappointed. I couldn't quite put my finger on why, but the sound was not as detailed, lively or musical as it had been. However, when I replaced the LM6181 with the LM6171 (a week later), the life and sparkle came back to my music. I want to try the LM6181 again this weekend to make sure that my hearing wasn't impaired by a cold I thought I was over. That said, I'm inclined to believe that the mod's (maybe the QC mod in particular?) favour the LM6171 more than the LM6181 which I suspect sounds better unmodified. 

 The plan for this weekend is to try the LM6181 again, then change R2 and R3 and see how it sounds with both op-amps. I'll report back.

 Mike; how are the AD843s burning in?

 EDIT: I meant to mention above that the lower frequency response and detail after the QC mod is stunning. It's quite unlike any headphone amp I've heard before._

 

Alick, it's imperative that you retrofit the 1k and 3k3 feedback resistors for both the LM6171 / LM6181... it sounds pretty stale with the lower value feedback resistors in situ..... you will notice a "dramatic" improvement with the QC mod "and" 1K and 3k3 feedback resistors back in place..... if you think it's good now just wait till you refit 1K and 3k3 
	

	
	
		
		

		
			





 Mike.

 PS: there is yet "another" mod which improves things even further according to David........ "solder a 330k resistor ( assuming you're using the 1k and 3k3 feedback resistors ) between pins 2 and 6 of the opamp for each channel. Leave the rail splitter opamp alone. The mod will reduce the hf and transient intermodulation distortion a little, but enough to be audible." I'll certainly be giving this a go once I get hold of a couple of 330K resistors.


----------



## Alick

Quote:


 Alick, it's imperative that you retrofit the 1k and 3k3 feedback resistors for both the LM6171 / LM6181... 
 

I'll try that next Mike. I left the optimised LM6181 values in as I intended to listen with that op-amp fitted first and I was very impressed with the LM6181 without the Zobel networks and increased QC. Funny how things turn out ...


----------



## PinkFloyd

Well I tried David's feedback distributor mod and am totally gobsmacked by what it has done to the LM6171 (and I mean gobsmacked!) It possesses the same resolution, the same insight... all the qualities of the LM6171 remain but the feedback distributor has added a touch of much needed warmth and smoothness to the sound... I won't waste time typing a load of fancy words trying to describe the sound but will say it's an LM6171 with added warmth and musicality..... I don't know how he's pulled this one off but he's managed to tailor the LM6171 to the tastes of the "LM6171 is ok _but_" brigade... there are no "It sounds ok _but_" to this chip now..... Clarity, resolution, detail, airiness are still there as before but the feedback regulator has tamed the chips tendancy to "shout" and has injected some very welcome emotion and warmth into the sound.

 This isn't one of these "you have to have ears like a bat to hear it" mods... this mod is palpable... you can hear it, and your emotions can reach out and connect with the music..... 

 The best part of it is...... it will cost you only 2 pence to try it out for yourself! All that's needed are 2 x 330K resistors. You solder each resistor across pins 2 and 6 of the LM6171's (not the rail splitter opamp... DO NOT perform this mod on the Rail splitter opamp) that's it...... as simple as that!





 The recipe to add soul and musicality to the LM6171 
	

	
	
		
		

		
		
	


	




 I didn't have any 330K resistors in my armoury and couldn't wait to try out the latest feedback distributor mod on the LM6171 so I went into perverse (clinically obsessed?) mode and connected 10 x 33K resistor in series to make 330K ...... I fitted them in series on veroboard and attached the 2 boards (one per channel) on top of the ALPS pot and ran wires from the resistor boards to legs 2 & 6 of the LM6171. I'll replace these string and sellotape series modules with single resistors attached direct to the legs of the LM6171 in due course (I will get around to forking out the 2 pence "+" postage..... honestly!)





 Cheapskates way of avoiding paying 2 pence for two 330K resistors 
	

	
	
		
		

		
		
	


	








 Another example of "use what you've got and save yourself 2 pence" but spend ages in labour saving that 2 pence 
	

	
	
		
		

		
		
	


	






 To date this is, by far, the best mod yet (and the cheapest) and it's, yet again, shown what a determined, capable, tweakable person the LM6171 is!!! As I say, I'm totally gobsmacked and I'm certain biovizier and the rest of you who "liked" the LM6171 "_but_" will absolutely fall in love with it with the feedback distributor in place (with no "_buts_).

 I'd go as far to say "audio Nirvana" (to my ears) Nice one Dr.White, I'm glad you added some personal alchemy to the measurements..... 95% measurements, 5% magic...... It works!!





 resistor connected across legs 2 & 6 of op amp

 Mike.

 EDIT: each mod is bringing about improvements to the sound, none more so than the Feedback distributor, but I'm finding it hard to remember the all the previous mods so I've decided to write them all down and upload them to a dedicated WNA mod page........ I should have that in place in a couple of weeks.

 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_




 Another example of "use what you've got and save yourself 2 pence" but spend ages in labour saving that 2 pence 
	

	
	
		
		

		
		
	


	




 To date this is, by far, the best mod yet (and the cheapest) and it's, yet again, shown what a determined, capable, tweakable person the LM6171 is!!! As I say, I'm totally gobsmacked and I'm certain biovizier and the rest of you who "liked" the LM6171 "but" will absolutely fall in love with it with the feedback distributor in place (with no "buts)._

 

hehe.. mike... you're getting better day by day.. just trying to imagine what would have happened, if dr. white had prescribed 667k resistors... 
	

	
	
		
		

		
		
	


	




 my 330k are on their way... (together with a bag of bd139/140... 
	

	
	
		
		

		
		
	


	




 )... i'll try it... 
	

	
	
		
		

		
		
	


	




 btw... that's top notch service by dr. white. can't say i often enough... what a crack!


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_hehe.. mike... you're getting better day by day.. just trying to imagine what would have happened, if dr. white had prescribed 667k resistors... 
	

	
	
		
		

		
		
	


	



_

 

Easy Peasy! I'd solder 667 x 1K resistors in series... you won't catch me out that easily 
	

	
	
		
		

		
		
	


	




 better still I could solder 1334 x 500R in series


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Easy Peasy! I'd solder 667 x 1K resistors in series... you won't catch me out that easily 
	

	
	
		
		

		
		
	


	


_

 

i'm absolutely convinced, you'd do so... 
	

	
	
		
		

		
		
	


	




...


----------



## PinkFloyd

Udo. every little penny helps....... The sad bit is I handmatched each "module" to make a perfect 330K


----------



## BrokenEnglish

gosh.. you must have been scottified... 
	

	
	
		
		

		
		
	


	







 /edit: Quote:


  Originally Posted by *PinkFloyd* 
_The sad bit is I handmatched each "module" to make a perfect 330K 
	

	
	
		
		

		
		
	


	


_

 

ah... stop it! can't breathe anymore..


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_gosh.. you must have been scottified... 
	

	
	
		
		

		
			






_

 

No, I was very sober when I made the modules up 
	

	
	
		
		

		
		
	


	




 I was a bit Scottified when I came up with these weirdos  on Boxing day 2004 tho...

 Thing is, they'd work great with a 100K trimmer 
	

	
	
		
		

		
		
	


	








 Seemed a good idea at the time


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Thing is, they'd work great with a 100K trimmer 
	

	
	
		
		

		
		
	


	


_

 

oh... things are getting interesting here... trimmers and mohms are on their way, too. maybe we'll get rid of the dc offset once for ever... but with my recent adventures i'll surely leave some output caps in...


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_ maybe we'll get rid of the dc offset once for ever..._

 

You can bank on it........... watch this space. days rather than weeks.

 Mike.


----------



## PinkFloyd

Bump for those who may have missed this cheap "best ever " tweak:


 Well I tried David's feedback distributor mod and am totally gobsmacked by what it has done to the LM6171 (and I mean gobsmacked!) It possesses the same resolution, the same insight... all the qualities of the LM6171 remain but the feedback distributor has added a touch of much needed warmth and smoothness to the sound... I won't waste time typing a load of fancy words trying to describe the sound but will say it's an LM6171 with added warmth and musicality..... I don't know how he's pulled this one off but he's managed to tailor the LM6171 to the tastes of the "LM6171 is ok _but_" brigade... there are no "It sounds ok _but_" to this chip now..... Clarity, resolution, detail, airiness are still there as before but the feedback regulator has tamed the chips tendancy to "shout" and has injected some very welcome emotion and warmth into the sound.

 This isn't one of these "you have to have ears like a bat to hear it" mods... this mod is palpable... you can hear it, and your emotions can reach out and connect with the music..... 

 The best part of it is...... it will cost you only 2 pence to try it out for yourself! All that's needed are 2 x 330K resistors. You solder each resistor across pins 2 and 6 of the LM6171's (not the rail splitter opamp... DO NOT perform this mod on the Rail splitter opamp) that's it...... as simple as that!





 The recipe to add soul and musicality to the LM6171 
	

	
	
		
		

		
		
	


	




 I didn't have any 330K resistors in my armoury and couldn't wait to try out the latest feedback distributor mod on the LM6171 so I went into perverse (clinically obsessed?) mode and connected 10 x 33K resistor in series to make 330K ...... I fitted them in series on veroboard and attached the 2 boards (one per channel) on top of the ALPS pot and ran wires from the resistor boards to legs 2 & 6 of the LM6171. I'll replace these string and sellotape series modules with single resistors attached direct to the legs of the LM6171 in due course (I will get around to forking out the 2 pence "+" postage..... honestly!)





 Cheapskates way of avoiding paying 2 pence for two 330K resistors 
	

	
	
		
		

		
		
	


	








 Another example of "use what you've got and save yourself 2 pence" but spend ages in labour saving that 2 pence 
	

	
	
		
		

		
		
	


	






 To date this is, by far, the best mod yet (and the cheapest) and it's, yet again, shown what a determined, capable, tweakable person the LM6171 is!!! As I say, I'm totally gobsmacked and I'm certain biovizier and the rest of you who "liked" the LM6171 "_but_" will absolutely fall in love with it with the feedback distributor in place (with no "_buts_).

 I'd go as far to say "audio Nirvana" (to my ears) Nice one Dr.White, I'm glad you added some personal alchemy to the measurements..... 95% measurements, 5% magic...... It works!!





 resistor connected across legs 2 & 6 of op amp

 Mike.

 EDIT: each mod is bringing about improvements to the sound, none more so than the Feedback distributor, but I'm finding it hard to remember all the previous mods so I've decided to write them all down and upload them to a dedicated WNA mod page........ I should have that in place in a couple of weeks.

 Mike.


----------



## 12796

I look forward to a shootout between the LM6171 and AD843 - I assume the LM6171 is ahead again?


----------



## 12796

I am not sure I like being leader of the Butt Brigade


----------



## PinkFloyd

.


----------



## StevieDvd

Mike,

 I've a spare pair of LM6171s and some 330R resistors at home. Is this a safe thing to try on my WNA mk1? Basically just swap out 2 standard LM6171s with 2 modded ones.

 Only changes since you sent me the WNA are the uprated output caps and the fix to the gain resistors.



 Steve


----------



## 12796

And certainly not gary glitter


----------



## PinkFloyd

Apologies Biovizier


----------



## PinkFloyd

.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Steve "330K" resistors, not 330R Perfectly safe for the Mk1 (and recommended) best thing to do is to solder a 330[size=medium]K[/size] onto the legs of your spare LM6171's..... that way you can compare the sound of standard LM6171 to the LM6171 with feedback distributor..... give it a go see what you think.

 Mike._

 

Whoops will 330 x 1K do then 
	

	
	
		
		

		
		
	


	





 Thanks


----------



## PinkFloyd

That will be fine Steve but a solitary 330K will take up less space.


----------



## Henry Morgan

Just tried the 330K accross pins 2&6 on LM6171 & I definitely think this improves things. The detail which the LM6171 is known for is still there but the bass seems much better to me too. Its seems to have the qualities of some others i've been trying e.g. AD8610 but with the high detail as well. Early days yet but John Martyn & John Mayall sound excellent so far. 
 Henry.


----------



## PinkFloyd

.


----------



## Alick

Having already added the Zobel networks, upped the QC and removed the lamps (and been slightly disappointed), then removed the LM6181s and refitted the LM6171s (and been a bit happier), I took Mikes advice yesterday and reverted to the original R2/R3 values and fitted the 330K between pins 2 and 6 of the op-amps. Here's a photo of how I did it in case anyone needs some ideas. (This is the right photo; the first one I posted was an earlier attempt with a wrong connection. 
	

	
	
		
		

		
			





) 






 What a difference. I was impatient and made both changes together so I don't know which has contributed most to the improved sound but who cares. For the cost of 4 resistors and two capacitors, this is an impressive upgrade. The bottom end has improved radically and provides impressive detail as well as "un-headphone-like" grunt and depth. I found myself listening more to the music than the amp (always a good thing, particularly when I was trying to pick out differences and the music defeated my objective) but still being surprised by odd details and highlights which stood out more than before. I need to listen more, but for enjoyment, not analysis.


----------



## BrokenEnglish

... stop it... i need to wait for parts, while you guys drift in your audio-nirvana.. that's not fair.. 
	

	
	
		
		

		
		
	


	




 /edit: alick, you've modded a mkII there, haven't you? nice take!


----------



## PinkFloyd

I just snipped the buggers legs and fitted him directly across 2 & 6 pads. Just the right length too which helped.


----------



## PinkFloyd




----------



## Alick

Quote:


 I just snipped the buggers legs and fitted him directly across 2 & 6 pads 
 

I didn't even try that, having convinced myself that the resistor would be too long. 
	

	
	
		
		

		
		
	


	




 Your way's much neater; I'll redo mine the next time I have the board out.


----------



## 12796

PF - perhaps you can briefly summarise at a high level the changes you have now made over the standard mark II. Do you plan to return to the ad843 at any point and try the local feedback oojamaflip or any of the component tweaks on that as well? It seemed a promising candidate and squuezing it gently and lovingly might take it past the lm6171 again. Just adding my But so dont bite it!


----------



## PinkFloyd

I had one of my rare (and to date least sensible) Head-Fi moments last night where I thought I'd delete all 4,674 of my posts 
	

	
	
		
		

		
		
	


	




 (don't ask) starting with this thread I managed to wipe out my posts on page 14 and page 1 before retiring to bed for the night.

 The posts are apparantly wiped from the server so I'll have to fill in the "dots" from memory... ah the silly things some people do when they're hot headed.... I'm just glad that I didn't wipe out everything.

 EDIT: ****! appears I actually reached page 2 as well.


----------



## 12796




----------



## FritzS

Hi all,
 I did not have a wna - but I study some pics and know as the schema works 
 My question - run the OP output driver in class A mode? 
 If not - one way is to put a constant current device from pin 6 to V- or the second way is to use different constant current devices (I1, I2) in the discrete class A output driver.


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Hi all,
 I did not have a wna - but I study some pics and know as the schema works 
 My question - run the OP output driver in class A mode? 
 If not - one way is to put a constant current device from pin 6 to V- or the second way is to use different constant current devices (I1, I2) in the discrete class A output driver._

 

Hi FritzS,

 I'm not sure I understand your question but the opamp is biased into Class A already.

 Cheers.

 Mike.


----------



## PinkFloyd

Hi Folks,

 I've decided to put a MKll tweaks page  together and would welcome any tweaks or tips you may have which I will include on the tweaks page. I'm not sure if I've covered all of the tweaks to date (still have to add the extra capacitance tweak) and haven't even mentioned all the other opamps that can be rolled in to the MKll but I'll get around to that over the next few weeks.... in the meantime have any of you guys tried any of the alternative opamps and, if so, what are your findings?

 I'd like to get as many opinions as possible and, with your permission, I'll add your comments and impressions onto a seperate "tweakers comments" page (yet to be constructed) Whether they are good impressions, bad impressions or indifferent I'd like to add them all... this will give the viewer the opportunity to read others opinions on the tweaks and not be limited to reading my opinions.

 To get the ball rolling I need your input, whether it be as little as "removing the incandescent lamp improves the bass response" or a 125 page theosis doesn't matter.. I'll add everything to the tweakers comments page be it good, bad or indifferent.

 Mike.


----------



## BrokenEnglish

great idea, mike! i hope you don't mind, including some of my impressions on the mkI:
 best tweak so far: remove those input caps, if your source allows it. more resolution, more fresh air between the notes, more bass also. 
 interesting finding: different opamps as railsplitter ic have there own signature... couldn't believe it first, but i had to roll them, because the ad825, that was in there, died (heavy oscillations after incautious caps rolling). tried the tl071 there... dull and boring, sound constricted; opa627: the highs went away... slow, uninvolving; ad8610: highs are back, but i miss some detail i had with the ad825.
 nevermind... i'll build a dual-psu and skip this part of the amp... will report back on that.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_great idea, mike! i hope you don't mind, including some of my impressions on the mkI:
 best tweak so far: remove those input caps, if your source allows it. more resolution, more fresh air between the notes, more bass also. 
 interesting finding: different opamps as railsplitter ic have there own signature... couldn't believe it first, but i had to roll them, because the ad825, that was in there, died (heavy oscillations after incautious caps rolling). tried the tl071 there... dull and boring, sound constricted; opa627: the highs went away... slow, uninvolving; ad8610: highs are back, but i miss some detail i had with the ad825.
 nevermind... i'll build a dual-psu and skip this part of the amp... will report back on that._

 

Ok to upload these comments Udo? Very interesting, especially with regard to the rail splitter opamp. 

 Mike.

 EDIT: LM6171 in the splitter is the way to go Udo............. I think you'll be over the moon once you fit LM6171 in place of the AD825....... just make sure you've fitted a Zobel Network first and the Oscillation God shouldn't be awoken 
	

	
	
		
		

		
		
	


	




 Cheers.

 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Ok to upload these comments Udo? Very interesting, especially with regard to the rail splitter opamp._

 

yes... of course... but please: feel free to correct my sloppy english.



  Quote:


 EDIT: LM6171 in the splitter is the way to go Udo............. I think you'll be over the moon once you fit LM6171 in place of the AD825....... just make sure you've fitted a Zobel Network first and the Oscillation God shouldn't be awoken 
	

	
	
		
		

		
		
	


	



 

i think so, too. i am trying to get another one for that purpose (contacted dr. white on that yesterday). but today my psu-pcbs arrived, so most likely i'll skip the railsplitter and use a dual-psu instead.

 /edit: btw... of course the lamps are out and the zobel is in...


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_I'm not sure I understand your question but the opamp is biased into Class A already. - Mike._

 

the most of the OP's output driver stage work's in Class A with a little idle current, but with greater output current she goes into class AB. So some (Jan Meier, and in other projects) gives a additional current source from output to V- so the NPN buffer transistor runs in poore class A. My idea in these project there gives 2 current sources in the output path - when you use this with different currents, the difference flows to the output of the OP.
 But today I have no WNA and did not know the schema details


----------



## BrokenEnglish

hi fritz,
 take a look at mike's tweaks-page. "tweak three" deals with parts of your question.


----------



## spendorspain

Hi,

 This is my first post, but I've interested in WNA HP amp for several months. I drove my Grado HP2 from the binding posts of my Copland CTA-501 power amplifier (30 watts, 4x EL34 valves ultralinear, high class AB) via the adaptor Grado suggests (simply a pair of high quality Caddock power resistors per channel). This amp is great sounding when driving a pair of Spendor SP-1/2 but on headphones the result was too soft and the highish noise of the valve output stage, acceptable when heard via loudspeakers, was less tolerable. 

 So, I decided to buy the WNA HP amp. The beefier MkII version seemed best suited for my low impedance cans, the price was very reasonable and the sound was very promising according the flood of favourable posts here and in other sites. Now, I have to say that this combo sounds superb 
	

	
	
		
		

		
			





 . After burning-in for two weeks I've found this amp very detailed and transparent ("fast", as others said) but natural sounding. Very familiar CDs (I listen to classical, mainly symphonic) show new details previously unheard, the different musical lines in complex passages are easier to follow, the effects of several tweaks (like the Mod Squad CD damper or different cables) are fully revealed, and all of this without sounding etched, cold or fatiguing. The only very minor shortcoming (in relation with the sound with Copland plus adaptor) is that the music is presented perhaps too close for my taste, with less depth, as I've moved several rows in the virtual concert hall.

 So good was the result than I couldn't resist the upgrading fever. I've chosen three mods. The most obvious was the removal of the lamp, the others were soldering a 330k beetwen pins 2 and 6 in LM6171 IC and the last (and more expensive...) was the use of Black Gate Nx 1000uF/25v as output caps. My plan was to make these changes and listen for possible improvements one at a time, but I've found the disassembly of PCB very difficult as it is necessary to unscrew the RCAs and the headphone socket to do this, due the very limited space in the case. As a result, yesterday I decided to do all the three tweaks at the same time. It's less "scientific", but a lot easier (only one disassembly and assembly process).

 At this moment the modified amp is burning-in. It seems the Black Gates need a very long burn-in process, and I'm not going to do any critical listening in two or three weeks. I'd like to include with this post several photos of the modifying process, but the size of attachments is limited to 25kb (is this normal?) and I don't have images so small. In a future post I'll report the subjetive sonic results (to my ears and according my musical tastes, of course).

 I'd like to thank all contributors to this thread for their efforts and enthusiasm and for keenly sharing their findings with the rest of music lovers.

 PS.: Pink Floyd, what about your past headaches? I too have "cluster" headaches and I understand you very well...

 Jose


----------



## PinkFloyd

Quote:


  Originally Posted by *spendorspain* 
_ Hi,

 This is my first post_

 

Hi Jose and welcome to Head-Fi and, if I may so, what an excellent first post!


  Quote:


  Originally Posted by *spendorspain* 
_So good was the result that I couldn't resist the upgrading fever. I've chosen three mods. The most obvious was the removal of the lamp, the others were soldering a 330k between pins 2 and 6 in LM6171 IC and the last (and more expensive...) was the use of Black Gate Nx 1000uF/25v as output caps._

 

Three very good mods to make and I'm sure you'll notice better bass definition, a slightly more smoother overall presentation whilst retaining all the good aspects of the LM6171 into the bargain. I haven't tried the Black Gates in the WNA but, from all accounts, they do take quite some time to form up..... I used them in the Graham Slee Solo to great effect but they took a good few hours before they kicked into action and when they did, boy did the amp sound good!

  Quote:


  Originally Posted by *spendorspain* 
_ My plan was to make these changes and listen for possible improvements one at a time, but I've found the disassembly of PCB very difficult as it is necessary to unscrew the RCAs and the headphone socket to do this, due the very limited space in the case. As a result, yesterday I decided to do all the three tweaks at the same time. It's less "scientific", but a lot easier (only one disassembly and assembly process)._

 

Tell me about it, it was bad enough removing the MKl from the "official" WNA enclosure, David sure does have the ability to cram things into tight spaces and I'm amazed he's managed to fit a MKll into that same enclosure! I believe he is now building them into the slighty larger black Hammond enclosures and will also build them into the clear anodised aluminium Hammond enclosures on request... they not only look better but servicing the amp is a breeze as you only have to remove one screw and the board slips out easily

  Quote:


  Originally Posted by *spendorspain* 
_At this moment the modified amp is burning-in. It seems the Black Gates need a very long burn-in process, and I'm not going to do any critical listening in two or three weeks. I'd like to include with this post several photos of the modifying process, but the size of attachments is limited to 25kb (is this normal?) and I don't have images so small. In a future post I'll report the subjetive sonic results (to my ears and according my musical tastes, of course)._

 

I'd really love to see the photos Jose and if you can e-mail them to me I'll upload them to a server and and post them here for you... I've sent you my e-mail address via PM so feel free to send them and I'll get your photos up here asap.

  Quote:


  Originally Posted by *spendorspain* 
_I'd like to thank all contributors to this thread for their efforts and enthusiasm and for keenly sharing their findings with the rest of music lovers._

 

Why thanks, and thank _you_ for sharing your experiences with us Jose your first post was very interesting and I, and the rest of us, will look forward to your comments once you've given the black gates a 100 hours or so to kick in... welcome aboard. 

  Quote:


  Originally Posted by *spendorspain* 
_PS.: Pink Floyd, what about your past headaches? I too have "cluster" headaches and I understand you very well..._

 

Touch wood they haven't returned, they were the first headaches I've ever suffered in my life, sods law that the headache should last for weeks... just par for the course with me I never do things by half measures 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


----------



## Alick

Welcome to the club Jose. I'm glad you seem as happy as the rest of us with your WNA. Just a thought; I wonder if it would be practical to form Black Gates (or indeed, any capacitors) before fitting them. Say, a few days tagged to a breadboard connected to the output of a cheap transistor radio or similar?


----------



## PinkFloyd

I've added details of adding a 10M resistor and trimpot to the tweaks page.

 As Follows:

 I personally like the idea of output caps as DC offset is zero with them in place, anyone who is really opposed to using output caps might like to try the following: Connect the track of a 100k trimmer potentiometer between 0V and -12V then connect a 10M resistor between the wiper of the trimpot and pin 3 of the LM6171. Adjust the trimpot for minimum offset, run for 30mins or so then readjust offset to mimimum. The original suggestion of connecting a 10M resistor between -12V and pin3 of the LM6171 usually overcompensated for the offset which would typically go from +200mV with no 10M resistor to -30mV with the 10M resistor. Even with the new mod the offset will drift a little with temperature but will still stay low enough for low impedance headphones to be used safely. Both David White and myself prefer using output capacitors as they offer the ultimate in dc output offset protection, and being non polar caps there will be minimum insertion loss (if any)





 Hope my diagram makes sense 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_I've added details of adding a 10M resistor and trimpot to the tweaks page._

 

great service, mike - always appreciated! thanks... will test it!


----------



## PinkFloyd

I received the photos of Jose's Black Gate output cap mod but had to make them a bit smaller in order they would remain within the width of the thread... beautifully detailed photos in full size but way too big for the thread.

 Here they are:





 Showing the difference in size between the Black Gate and the Nitai Caps





 A close up of the Black Gate





 The Black Gates in situ





 Black Gate from another angle





 330K resistor in position

 Very nice work Jose, I actually thought the black gates would be a lot larger... they're a very good size and the way you have fitted them is great.

 I see that Dr. White is fitting the 0.1% 15ppm Trueohm resistors now, I believe there were supply problems with the RC55Y's (getting the right values) so he must have moved over to the equally superb Trueohms..... nice looking job!

 All the best.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_the most of the OP's output driver stage work's in Class A with a little idle current, but with greater output current she goes into class AB. So some (Jan Meier, and in other projects) gives a additional current source from output to V- so the NPN buffer transistor runs in poore class A. My idea in these project there gives 2 current sources in the output path - when you use this with different currents, the difference flows to the output of the OP.
 But today I have no WNA and did not know the schema details 
	

	
	
		
		

		
		
	


	


_

 

Hi FritzS,

 I'm reliably informed that there is no driver stage, the opamp drives a pair of paralleled class A emitter followers directly.

 I trust this is of help 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## Edwood

I was surprised that the 25V 1000uF NX's were shorter than I thought. They are definitely stubbier than their FK series counterparts. 

 I still had to "bend over" mine in my Bel Canto DAC2.

 They barely clear the inside of the case even bent over.

 -Ed


----------



## PinkFloyd

Quote:


  Originally Posted by *Edwood* 
_
 I still had to "bend over" mine in my Bel Canto DAC2.
_

 

Nice job of cap bending Ed. Hell, there's "tube rolling", "Opamp rolling" so why not add "cap bending" into the vocabulary 
	

	
	
		
		

		
		
	


	




 , I like the way you've used cable tie mounts and secured the caps onto them with cable ties.... I used sticky fixers to mount my BG's and Cerafines on the Solo as the amp isn't going to be travelling but if it was ever to fly anywhere I'd strap them down with sticky fixers and cable ties for sure.


----------



## StevieDvd

Does the addition of the 330k resistors have an effect on the gain? It seems I need to turn the volume up more than usual. 
	

	
	
		
		

		
		
	


	




 I've put 2 on the LM6171s and will give them a run in over the weekend and swap back to 2 standard LM6171s to check the difference. To do this I switched the rail splitter back to an OP627 (only had 4 LM6171s), not sure if this is related.

 I'll try with 3 LM6171s over the weekend - two 330K bridged and the splitter.

 Any thoughts?


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Does the addition of the 330k resistors have an effect on the gain? It seems I need to turn the volume up more than usual. 
	

	
	
		
		

		
		
	


	




 I've put 2 on the LM6171s and will give them a run in over the weekend and swap back to 2 standard LM6171s to check the difference. To do this I switched the rail splitter back to an OP627 (only had 4 LM6171s), not sure if this is related.

 I'll try with 3 LM6171s over the weekend - two 330K bridged and the splitter.

 Any thoughts?_

 

You haven't fitted a 330K to the OP in the rail splitter I hope??? Just fit the 330K between pins 2 & 6 of IC1 Steve... leave IC2 alone. There should be "no" effect on the gain whatsoever, double check you've connected the 330K between 2 & 6:










 Underside view 

 You've got a MKl but that shouldn't make any difference... should work with any amp.

 There's no reason why a 627 in the rail splitter should reduce the volume..... you say you've got 4 LM6171's? pop one of them in the splitter and see what happens..... either that or reverse the mod but keep the 627 in the rail splitter, if there's still a reduction in volume then you've got your answer..... 

 Mike.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_You haven't fitted a 330K to the OP in the rail splitter I hope??? Just fit the 330K between pins 2 & 6 of IC1 Steve... leave IC2 alone. There should be "no" effect on the gain whatsoever, double check you've connected the 330K between 2 & 6:_

 

2 & 6 for sure I checked several times, and not the splitter opamp.

  Quote:


  Originally Posted by *PinkFloyd* 
_There's no reason why a 627 in the rail splitter should reduce the volume..... you say you've got 4 LM6171's? pop one of them in the splitter and see what happens..... either that or reverse the mod but keep the 627 in the rail splitter, if there's still a reduction in volume then you've got your answer..... 

 Mike._

 

Will do was planning to try both those but I don't recall reading of an expected gain change so am a little puzzled. It sounds fine but I'd like to hear the difference and choose the one I prefer - I now know my taste is different to others so it's me I need to satisfy soundwise now.

 I'll double check in case the rainbow foil was disturbed


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_2 & 6 for sure I checked several times, and not the splitter opamp._

 

So far so good.


  Quote:


  Originally Posted by *StevieDvd* 
_ I don't recall reading of an expected gain change so am a little puzzled._

 

There is no gain change Steve, check for a dry joint between 2 & 6. 


  Quote:


  Originally Posted by *StevieDvd* 
_ It sounds fine but I'd like to hear the difference and choose the one I prefer - I now know my taste is different to others so it's me I need to satisfy soundwise now._

 

Of course but let's get the 330K tweak working before you choose....... if there is a reduction in volume after fitting the 330K then something's not right.

  Quote:


  Originally Posted by *StevieDvd* 
_I'll double check in case the rainbow foil was disturbed 
	

	
	
		
		

		
		
	


	


_

 

I'll never live that down will I? 
	

	
	
		
		

		
		
	


	




 Haunted forever by cheap Rainbow Foil quips........


----------



## bludragon

Well, I've just ordered enough components to cover all the tweeks - here are the rapid part numbers if anyone wants to save a little time:

 63-1744330K20.250.59 - The feedback distributor
 63-100010R20.250.59 - The Zobel Network
 62-2550100R11.802.12 - Increase the quiescent Current (pack of 100)
 62-2560160R11.802.12 - Increase the quiescent Current (pack of 100)
 08-0940100pF100.070.82 - extra psu decoupling
 08-0945220pF100.070.82 - extra psu decoupling
 11-3636470µF100.333.88 - extra psu decoupling
 10-1340100nF40.160.75 - The Zobel Network (you only need 2 - also not sure if these are the best type for this purpose)
 36-0198Type TV4 SOT32120.395.50 - Increase the quiescent Current

 Came to a total of a not so insignificant £21.24 with delivery.

 btw, don't blame me if I ordered something incorrectly (please tell me though ). Also I haven't checked to see if better/cheaper parts are available anywhere else (yes, I'm lazy).

 One last thing, any thoughts on matching the output transistors?


----------



## BrokenEnglish

Quote:


  Originally Posted by *StevieDvd* 
_Does the addition of the 330k resistors have an effect on the gain? It seems I need to turn the volume up more than usual. 
	

	
	
		
		

		
			





 I've put 2 on the LM6171s and will give them a run in over the weekend and swap back to 2 standard LM6171s to check the difference. To do this I switched the rail splitter back to an OP627 (only had 4 LM6171s), not sure if this is related._

 

can't say anything about effects of the 330k mod. but i can for sure tell you, that my wna mkI sounded really OFF with the opa627 as railsplitter ic. 

 i'll test the 330k mod after burn-in of the new caps (c3/c5). personally a simple gain-reduction wouldn't disturb me..


----------



## PinkFloyd

will add parts list here.


----------



## bludragon

lol, thanks pinkfloyd.
 The caps I labelled as 'extra psu decoupling' aren't for any of the mods you've detailed, but I wanted to have a play with sprinkling some between power and ground - the 100pF are ceramics, which are often recommended as additional psu decoupling caps for op-amps.

 The packs of 100 resistors I obviously got because they didn't do any smaller quantities.

 My mistake on the heatsinks I guess, but I hope I can massage them in anyway.

 By the way, I just spend the morning auditioning some new headphones, and had the opportunity to pit the WNA mkII (in standard guise) against a Project Headbox (£150). You'll be glad to know it did come out on top - this was through a pair of HD600's and driven by an arcam cd73t.


----------



## BrokenEnglish

Quote:


  Originally Posted by *bludragon* 
_By the way, I just spend the morning auditioning some new headphones, and had the opportunity to pit the WNA mkII (in standard guise) against a Project Headbox (£150). You'll be glad to know it did come out on top [...]_

 

he... no problem to top the pro-ject headbox... 
	

	
	
		
		

		
		
	


	




 even my go-vibe sounded superior to the headbox to my ears. i'd say, the wna plays in a different league...


----------



## PinkFloyd

Whoops, regular readers of this thread will remember I fitted a 2200uF capacitor into C7 on the railsplitter.. everything is working fine except the current has wiped out I3 and I4 (the 5.6mA current regulator diodes)

 Another head-fier has also been experimenting with cap values in the railsplitter and it seems 220uF is the absolute maximum that should be used..... if you use anything higher than 220uF in the "MKl" it may wipe out TR3 and TR4 and anything higher than 220uF in the MKll will take the current regulating diodes out (and possibly TR5 & TR6) as they can't handle the very large current passing through them at switch on.

 Thing is, the amp is still working and sounding great but I suspect it will sound even better once I replace the CRD's and refit the 220uF cap at R7.

 Anyone who has replaced the cap at C7 with anything higher than 220uF is advised to check the voltage across the CRD's if they measure close to 0V you know they're shot and will need replacing...... it's also worth checking the voltage between the collector and emitter of Tr5 and Tr6..... if they measure from 0.5-2.0V you're okay but if they measure zero then they too will have to replaced with new ones.

 Glad I measured the voltage across the CRD's or I'd be none the wiser 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## StevieDvd

Whoops from me as well 
	

	
	
		
		

		
		
	


	




 Checked the solder joints, tried a few swaps of the opamps and nothing seemed to change the difference in the gain.

 Stepping back and thinking it through I double checked the PC and I'd somehow dropped the volume on the Emu0404 patchmixer panel (where's the red faced smiley when you need it).

 Anyhow it's back with 3 LM6171s with the 330Ks fitted - wow!

 Much better, the best combination so far. Time to use it for listening to music again (like right now - Mark Knopfler Shangri-La).

 Nice one Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Whoops from me as well 
	

	
	
		
		

		
		
	


	




 Checked the solder joints, tried a few swaps of the opamps and nothing seemed to change the difference in the gain.

 Stepping back and thinking it through I double checked the PC and I'd somehow dropped the volume on the Emu0404 patchmixer panel (where's the red faced smiley when you need it).

 Anyhow it's back with 3 LM6171s with the 330Ks fitted - wow!

 Much better, the best combination so far. Time to use it for listening to music again (like right now - Mark Knopfler Shangri-La).

 Nice one Mike._

 

Heh,

 Talking about red faced smilies, I've been listening to the MKll with two blown 5.6mA constant current diodes for almost a month <insert red face smiley here!> and it still manages to sound **** hot....... I think I'll be doing a bit of "wowing" once I replace them with new ones and retrofit the 220uF cerafine in C7!

 Have a listen to the WNA (with 330K feedback distributor) with your Creek CDP Steve, you may be pleasantly surprised 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## BrokenEnglish

ehem... *cough*... and don't forget to get rid of those input caps (if your source allows to)...


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Heh,
 Have a listen to the WNA (with 330K feedback distributor) with your Creek CDP Steve, you may be pleasantly surprised 
	

	
	
		
		

		
		
	


	




 Mike._

 

You reading my mind?

 The WNA has been on the PC mainly due to me playing with the PC music setup and spending less time than I wished using the Creek. I've got a Emu0404 adapter coming from Fidaudio to see if the DAC in the current setup is worth keeping. After that some musical chairs with the amps, headphones and headphone cables.


----------



## PinkFloyd

On reflection....... not a good idea 
	

	
	
		
		

		
		
	


	




 I must have had one of my "rainbow" moments when I thought that one up 
	

	
	
		
		

		
		
	


	




 oh well, no real harm done just a couple of CRDs to replace and a retrofit of caps.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Nice one Mike._

 

"Nice one David" that should read.

 Mike.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_"Nice one David" that should read.

 Mike._

 

Or to be fair "Nice one David and Mike" after all how else would we hear of these tweaks.


----------



## FritzS

For best performance - Black Gate as a super-E-Caps capacitor









 at WNA you can use 2x 220μF .... 2x 470μF at output

 More about
http://www.blackgate.jp/ebg6.htm
http://www.stockhammer.at/hifi/hifi-...php#Capacitors
http://www.stockhammer.at/hifi/audio....php#BlackGate

http://www.blackgate.jp/image/ic_e.pdf


----------



## Alick

My Mk2 with all the mod's is improving with burn-in. I had a wonderful listening session last night; there was fantastic detail across the spectrum, I was easily able to follow and position individual instruments and voices, silence was silence but, above all, nothing detracted from the music, in which I was completely lost for two hours. 
	

	
	
		
		

		
		
	


	




 A question for everyone who's done the mod's. Since I tweaked the QC, I've been running with the lid off, keeping an eye on the temperature of the output transistors. They do run quite hot, even with heatsinks. Has anyone ventilated their lid or are you just running with the Hammond lid in situ as is?


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_A question for everyone who's done the mod's. Since I tweaked the QC, I've been running with the lid off, keeping an eye on the temperature of the output transistors. They do run quite hot, even with heatsinks. Has anyone ventilated their lid or are you just running with the Hammond lid in situ as is?_

 

Hi Alick,

 Yes, the core temp. of the transistors rises from 60C to around 80C once you increase the quiescent current so heatsinks are a must. These are the transistors Rapid supply Alick, have a look at the spec sheet and you'll see that 80C is acceptable.

 I don't ventilate the case and just let it run warm. One thing you may want to do is to change the 85C caps in C5 & C6 over to 105C caps as they are sitting right next to TR3.

 Mike.


----------



## Alick

As luck would have it, I fitted 105C cap's when I populated the board and the heatsinks are in place, so on with the lid it is. Of course, as soon as I close the lid, David will have another flash of inspiration ...


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_As luck would have it, I fitted 105C cap's when I populated the board and the heatsinks are in place, so on with the lid it is. Of course, as soon as I close the lid, David will have another flash of inspiration ..._

 

Latest Mod announcement: "fit hinges to the lid"


----------



## Paco

Hello all,
 It's my first post here, but I've been reading for a long time. Impressive contribution from you all, especially Pink Floyd, thanks!
 I've built the MKI and I'm finishing the MKII. I'm using the MKI, with a WNA Cascode Power Supply as preamplifier together with the WNA MOS125 amplifier. I use a 10K DACT stepped attenuator instead of the ALPS pot. I’m finishing the MKII and I’m going to use it as headphone amplifier with a Senheiser HD600.
 I’ve tested several opamps in the LM6171 modified MKI (without input / output caps):
 OPA134
 OPA627
 AD744
 AD845
 AD843
 AD825
 AD8610
 And of course LM6171.
 Those are some of my thoughts regarding those tests:

 The OPA627 gives a very nice tonality to guitars, violins, etc but overall is sound dark to me.
 The AD8610 gives a lot of air, but some times it looks there’s too much air… a bit fatiguing. Never goes over 40ºC.
 AD825 looks to put the correct air but lacks the nice tonality of the AD8610. It gets to 55ºC approximately… it may be dangerous in the hot Spanish summer.
 I didn’t like the AD843. Too much "artificial air" and somewhat “metallic” sound to my ears.
 The winner, to me is LM6171. The correct air, very good tonality, impressive detail (modified with the 330K resistor).
 I have the LM6181, AD844 and AD8065 waiting to be tested…

 Best regards,
 Paco


----------



## 12796

Thanks! 

 Very interesting - can't wait to hear your next lot of findings. What ancillary equipment are you using re: source, speakers etc? How are you finding the mos125? I am going to be purchasing a pair each of mos125/250/500 for tri-amping and already use a WNA volco/preamp and phono stage (soon to be supplemented by a headamp as well!). Perhaps you can contact me privately with regards to the MOS125 as it is not really relevent to this thread. 

 Regards,

 Nick.


----------



## PinkFloyd

Quote:


  Originally Posted by *Paco* 
_Hello all_

 

Hi Paco,

 Welcome to Head-Fi, great first post!

 I look forward to your comments re: the LM6181, AD844 and AD8065 have you got the 330K resistor in place? It helps a lot.

 All the best.

 Mike.


----------



## Paco

Hi Mike,

 Yes, the LM6171 is modified with the 330K.
 I’ve tried the AD844 during the weekend... horrible, the worse I've tried. I still haven’t tried the other opamps.
 I've also found out that the OPA627 works very well when you use a very transparent sounding CD. I'm using it with a modified Philips CD723. It has a completely modified PSU, most of the electrolytics has been bypassed, the opamp is AD8620 and output caps has been substituted by Mundorf MCap ZN, Mundorf Supreme Silver in Oil and Ero MKP 1837 (all paralleled). With this CD and using the MKI without input and output caps, the OPA627 sounds awesome. The violins sound is real and credible; you can feel the wood and gut taste (I don’t know if I’ve expressed it in a correct way… cut number 5 from Tacet’s “Das Mikrophon” is extremely complicated to reproduce correctly and thus a revealing test), having a very good soundstage (Prokofiev’s “Dance of Knights” from "MY DISC": The Sheffield Lab / A2TB Test Disc is a very nice test) and with a natural and relaxed sound. Anyway, the attack and definition of the LM6171 is better to me (first cut from Sheffield Lab’s “MY DISC”).
 When using the other CD that I own, a non-modified Marantz, the winner is the LM6171+330K and the OPA627 is too "dark" with most of my music. To me, the sound of the OPA627+modified CD723 is better for classical music while the LM6171+Marantz is better for jazz-rock. Just my personal point of view. 

 Best regards,
 Francisco


----------



## PinkFloyd

Hi Francisco,

 My WNA has gone to a new home today so I'll have to wait until I've built another one before I can compare notes on opamps with you.... I too really liked the OPA627 but it was a tad too warm and chocolaty when listening to rock music.... I don't listen to much classical these days but I certainly will pull out some Bruckner, Rachmaninov, Tchaikovsky and Beethoven and will have a darned good listen to them with the OPA627 as soon as I build the next WNA 
	

	
	
		
		

		
		
	


	




 I'm really terrible when it comes to DIY amps... I love building them, love tweaking them and love talking about them but once they are complete my fingers start itching and I have an insatiable urge to build another one and the entire process starts all over again! 

 Fortunately, every time I build up a new WNA kit some other tweak appears so I trust this will be the case with the next one I build 
	

	
	
		
		

		
		
	


	




 I'm thinking that this time I will take photos of _every_ stage of the build and upload a pictorial build tutorial (now that I've mastered the "Macro" feature on my camera!) which may be helpful to newbee builders.... something along the lines of "step 1: fit xyz resistor to R3" (accompanied by a picture of the resistor in position) and continue this build guide across the board..... there would be tons of pictures (hundreds) and it would take quite some time to put together.... question is, would it be helpful or would I just be wasting my time? 

 How are you getting on with the MKll Francisco? The only fiddly part of the build IMO is the wiring from the railsplitter to the amp.... that could be addressed in MK3 (if there's going to be a MK3) and the size of the PCB could be increased so it could slot into the Hammond enclosure and the pitch for the caps could also be widened for people who want to fit larger "audiophile" caps. The use of hook up wire should only be necessary between DC input to board and phono input to board IMO what do you think?

 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_The only fiddly part of the build IMO is the wiring from the railsplitter to the amp...._

 

hi mike,
 to make things a bit more complex, i thought about adding a switch to my future mkII, that allows me to jump between single voltage supplies (via railsplitter) and an external dual voltage psu (bypassing the railsplitter). maybe you want to walk at the front?


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_hi mike,
 to make things a bit more complex, i thought about adding a switch to my future mkII, that allows me to jump between single voltage supplies (via railsplitter) and an external dual voltage psu (bypassing the railsplitter). maybe you want to walk at the front? 
	

	
	
		
		

		
		
	


	


_

 

Good idea..... could also be implemented with jumpers on the board which would negate the need for a switch.

 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Good idea..... could also be implemented with jumpers on the board which would negate the need for a switch._

 

yeah... but a switch is more comfortable to compare the benefits of different psus with your ears...


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_yeah... but a switch is more comfortable to compare the benefits of different psus with your ears..._

 


 What about an output impedance switch and a switch which will give you crossfeed......... oh and what about a bass boost switch?

 Hell man I want a straight wire amp........ a dedicated DIY headphone amp with "no" options...... just a kick arse painting by numbers kit devoid of switches which sounds the best.

 Having said that an overly complex PCB with "options" would be nice but I would prefer a simple "this is the best WNA" Kit amp and tweak around the board......... I detest these designs that aren't clear and leave spaces for "every" eventuality...... they confuse me....... I want a DIY amp that a monkey can make and I want it to sound "awesome" as stock. 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## Alick

Quote:


 I want a DIY amp that a monkey can make and I want it to sound "awesome" as stock. 
 

Admit it; you'd still want to tweak it. 
	

	
	
		
		

		
		
	


	




 On Broken English's idea, I'm less against switches in the PSU lines than the audio signal path. I haven't thought it through, but you could probably do something using switching connectors to automatically detect the presence of a plug to switch between PSU options. The other option would be to have a three position power switch with a centre "OFF". Up could be "INTERNAL RAIL SPLITTER" and down "EXTERNAL DUAL SUPPLY". That would probably need a 4PDT with centre off. Maplin do them.


----------



## Paco

Hello Mike,
 I’ll be waiting for your results. It’s difficult to find a musical system that makes everything sound ok. I agree with you that pop-rock sound too warm with the OPA627. Maybe the best compromise is the LM6171, it isn’t as warm as OPA627 but you can listen to classical music without the excess brightness that my ears find on the AD8610, for example. So If I had to choose one opamp for all the time I could probably pick the LM6171+330K.

 Well Mike, I’ll be waiting for your new findings regarding the WNA headamp! Your idea regarding the pictorial tutorial sound great, an image is sometimes better than 1000 words.

 I have the MKII board populated with the components; it’s an easy job. I have to make the cabling and start listening… but I’m too busy at the moment and maybe I’ll wait to hear about your new findings before finishing mine 
	

	
	
		
		

		
		
	


	




 ! Of course, a version that need so little cabling will be even easier to build and will look better. 

 Regards,
 Francisco


----------



## PinkFloyd

Quote:


  Originally Posted by *Paco* 
_
 Well Mike, I’ll be waiting for your new findings regarding the WNA headamp! Your idea regarding the pictorial tutorial sound great, an image is sometimes better than 1000 words._

 

I'll order the board up in the next couple of weeks and will try my best to take longer than an hour populating the board and take a photo of every part of the build..... I've decided to go all out with Nichicon MUSE fine gold caps, polyprop caps, 0.1% resistors etc. in this one just to see if these (claimed) "audio grade" components make a difference..... I know that different flavours of capacitors can change the sonic signature of the amp but I'm sceptical when it comes to 0.1% 15ppm resistors V 1% 50ppm varieties. Some people claim that the 15ppm temp. coefficient resistors "sound" better than the 50ppm..... I must confess I've never been able to hear any difference between the two but I'll fit the 0.1% 15ppm variants anyway.

  Quote:


  Originally Posted by *Paco* 
_I have the MKII board populated with the components; it’s an easy job. I have to make the cabling and start listening… but I’m too busy at the moment and maybe I’ll wait to hear about your new findings before finishing mine 
	

	
	
		
		

		
		
	


	




 ! Of course, a version that need so little cabling will be even easier to build and will look better._

 

Yup, populating the board is a breeze but the hook up wire should be kept to a bare minimum, I agree. The Chiarra kit was (is) great in that respect, the only hook up wire that was required was between DC in and board and Phono in and board...... the rest of the PCB was wire free and circuit options were jumperable..... I've got nothing against "wire" per se' but it's a pain in the arse if you're constanly in and out trying different components.... it gets in the way and, yes, it looks untidy into the bargain.

 I don't know if there "will" be a MKlll but, if there ever is, I'd prefer it to be practically wireless with any PSU options jumperable on the board....... the jumperable pads could even be on the topside of the board which would negate the need to strip the amp down to access the underside of the board if you wanted to mess around with different PSU's etc. 

 Anyways "if" there ever is a MKlll in the future I'll be building one up whether it's wire free or not..... This is one superb amp and I'm sticking with it long term, I've got confidence in the designer and I love the WNA signature sound.

 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_I'll order the board up in the next couple of weeks and will try my best to take longer than an hour populating the board and take a photo of every part of the build..... I've decided to go all out with Nichicon MUSE fine gold caps, polyprop caps, 0.1% resistors etc. in this one just to see if these (claimed) "audio grade" components make a difference..... I know that different flavours of capacitors can change the sonic signature of the amp but I'm sceptical when it comes to 0.1% 15ppm resistors V 1% 50ppm varieties. Some people claim that the 15ppm temp. coefficient resistors "sound" better than the 50ppm..... I must confess I've never been able to hear any difference between the two but I'll fit the 0.1% 15ppm variants anyway._

 

i'm really looking forward to your picture guide, mike... oh and to your imressions on parts-upgrades. btw... are you the new mr. ampless around? 
	

	
	
		
		

		
		
	


	



 hm... i thought gold-caps are used as a sort of power-storage... am i wrong?

  Quote:


 I don't know if there "will" be a MKlll but, if there ever is, I'd prefer it to be practically wireless with any PSU options jumperable on the board....... the jumperable pads could even be on the topside of the board which would negate the need to strip the amp down to access the underside of the board if you wanted to mess around with different PSU's etc. 
 

that would definitely be a great ease... 

  Quote:


 This is one superb amp and I'm sticking with it long term, I've got confidence in the designer and I love the WNA signature sound. 
 

have to second that whole-heartedly...


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_ btw... are you the new mr. ampless around?_

 

Fortunately I'm not ampless I've got the quite surprising (Gmoy) as back up as well as a few other amps.

 Cheers.

 Mike.


----------



## 1UP

Ditto, Paco, how do you find the MOS125 (in comparison to other commercial power amps)? Feel free to PM me.


----------



## Paco

I think that not using cable is easier but, at lest in theory, a good cable will do a better job than a PCB track and you can try differents options. When I wire my loudspeakers crossovers I allways use point to point conections instead of PCBs.
 Hi 1Up, I'll send a mail.

 Regards.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_ i thought gold-caps are used as a sort of power-storage... am i wrong?
_

 

Hi Udo,

 You're perfectly correct but Nichicon "fine gold" are gold only by name and colour... mine arrived today and I can't wait to try them out when I build the next WNA 
	

	
	
		
		

		
			





 Here's why they call them "fine gold"


----------



## PinkFloyd

Quote:


  Originally Posted by *Paco* 
_I think that not using cable is easier but, at lest in theory, a good cable will do a better job than a PCB track and you can try differents options. When I wire my loudspeakers crossovers I allways use point to point conections instead of PCBs.
 Hi 1Up, I'll send a mail.

 Regards._

 

Hi Paco,

 Take it from me that "no cable" is best when using the LM6171 and if you do use cable it's best to keep the runs as short as possible otherwise the oscillation god will make an appearance as many WNA / LM6171 builders have found out 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_You're perfectly correct but Nichicon "fine gold" are gold only by name and colour... mine arrived today and I can't wait to try them out when I build the next WNA 
	

	
	
		
		

		
		
	


	




 Here's why they call them "fine gold"_

 

oh... ohhh... nice! what made you choose particularly these caps, mike?


----------



## individual6891

Quote:


  Originally Posted by *BrokenEnglish* 
_oh... ohhh... nice! what made you choose particularly these caps, mike?_

 

And where did you get them from?


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_[...]"no cable" is best when using the LM6171 and if you do use cable it's best to keep the runs as short as possible otherwise the oscillation god will make an appearance [...]_

 

ever encountered oscillation behind the railsplitter, mike? what symptoms did you realize?


----------



## Alick

Mike, have you got a new camera?


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Mike, have you got a new camera?_

 

Unfortunately not but I've mastered the "macro" button...... amazing what 
 a 1 mega pixel camera can do eh?

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *individual6891* 
_And where did you get them from? 
	

	
	
		
		

		
		
	


	


_

 

None of your business


----------



## individual6891

Quote:


  Originally Posted by *PinkFloyd* 
_None of your business._


----------



## skyskraper

i cant speak for the UK, but down under RS has just started carrying muse fg caps. 

 im gonna try some out soon, but theyre a lot pricier then fc's or zl's, i dunno if i have high hopes for em.


----------



## PinkFloyd

Quote:


  Originally Posted by *PinkFloyd* 
_None of your business._

 







 I could have sworn I put the winking smiley on the end of that "
	

	
	
		
		

		
		
	


	




"

 Sorry mate, I got them in the USA I don't know if you can source them in the UK 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


----------



## individual6891

Found them in the RS/AU's 2006 catalogue, which isn't released yet in UK yet.

 Hopefully, UK should have them in stock by end of may.. This is about the right time of the year for catalogue launch.

 Edit- you weren't kidding about the price huh?! 

 p.s. It's ok mike "
	

	
	
		
		

		
		
	


	




"


----------



## PinkFloyd

70 cents each from Michael Percy Audio http://www.percyaudio.com/Catalog.pdf


----------



## spendorspain

Hi,

 I have a modified WNA MkII headphone amp (330k tantalum resistor fitted in the LM6171, IC1 soldered directly to the PCB without socket, lamp removed and Black Gate Nx 1000uF/25v output capacitor). After nearly three weeks of continuous playing (so it is well burned in) the sound it produces is simply magic. I can “hear into” the recording so the music is no more a nice tapestry of sound, but the sum of various elements, each clearly different and individual. I discover so many new details in CD’s I’ve heard dozens of times that I have the impression of hearing a new disc: the subtle vibrato of massed strings, the difference between two or more instruments when playing simultaneous a tune, the inflections of a voice, the placement of any instrument in the soundstage, those extramusical noises that add realism to the recording (the musicians breathing, touching their instruments or their scores, humming along the music, the reflections in the venue walls clearly differentiated from the direct sound, the decay of notes…), etc. I can pick any specific instrumental or vocal line and easily follow it and hear it in the midst of the orchestration. The extreme bass extension and the feeling of tridimensional space (things very difficult for a headphone to reproduce) are very well presented. There is no edge or unmusical sharpness, but a delicious “golden” glow to the music… Bright discs are bright, dull discs are dull, bad recordings are bad, but the result is always musical and enjoyable and a well recorded disc is… simply glorious. I’d like to express better what I hear and feel, but my English and this space are limited. In a few words, I can imagine myself “in” the concert hall and forget I’m hearing a recording everytime I put the headphones on my head 
	

	
	
		
		

		
			














 .

 I don’t know what percentage of this is attributable to each of the modifications (I've made them all at a time), but there is a definitive improvement over the standard amplifier (that sounded indeed very good as delivered) and I can even justify the high cost of Black Gates (at the price of only 2-3 CDs I believe it IS really a cost-effective upgrade in musical pleasure terms).

 At the moment, all I want is to enjoy the music through the WNA and the Grado HP-2 headphones but, as this amp is even more upgradeable, I hope to improve it soon, perhaps adding a WNA cascode PSU (I’m sure that the wallwart adaptor supplied with the amp is the weak link). So, there goes my questions:
 Do you have a WNA MkII with this PSU? 
 What are the sound improvements (power supplies does matter in amplifiers, I think)? 
 Is it easy to build it (includes the transformer, fuse, case, etc)? 
 Is it possible to use the same WNA cascode PSU for powering the hp amp and the WNA active tone controls (I’m thinking about making a “pre-plus-hp” amp tailor-made for my needs)?… 
 Any info on this subject will be appreciated.

 Kind regards,
 Jose


----------



## Paco

Hello again,

 Well, I've contiunued with listening tests and my result is... the LM6171+330K is the clear winner. I had been listening to the OPA627 for more than one week. It's easy to go to the OPA627 when you are listening to classical music, it's a very nice opamp for this kind of music. But after this time I've gone back to the LM6171 and the change is dramatic. It's better in everything except, as I said, the nice tonality that OPA627 gives to the string instruments. But you loose much more that you win, and it's clear once you go back to the LM6171 again!

 Regards.


----------



## 1UP

Hi Jose,

 Thanks for your enjoyable post - your English is excellent, btw. 

 Unfortunately, I have no DIY skills or knowledge, so I got a fully-assembled Cascode PSU for my MKII headamp. It brings a lower noise-floor, greater detail and dynamics, better instrument separation, and an on-off switch! 
	

	
	
		
		

		
		
	


	



 I love it! 

 Headfi user Captain also happens to be selling one on the for sale forums right now for a discounted price!

 P.S. The WNA mains cables are also worth investigation, bringing more of the same qualities noted above.


----------



## BrokenEnglish

hi 1up,
 is your cascode psu configured to feed the mkII with dual- (bypassing the railsplitter in the amp) or single-voltage?
 thanks!


----------



## 1UP

No idea. Is there some way I can discern this?


----------



## BrokenEnglish

dual voltage requires at least three-pole connectors (and your amp has to be modified, too), while single voltage uses a two-pole connector, usually a small (5,5mm diameter) plug with center-hole. if you used the amp with an "ordinary" wallwart (sv) before and didn't modify it, most likley your cascode uses sv, too.


----------



## PinkFloyd

Quote:


  Originally Posted by *1UP* 
_No idea. Is there some way I can discern this?_

 

email David and ask him or take a pic of the guts of your amps and post it, it's easy to tell....... you're cascode is probably single voltage connected to P4 running through the rail splitter..... if it's dual voltage it will bypass P4 (the rail splitter) and go direct to P3 (left channel) and P3 (right channel) if you open the amp up and follow the wires from the DC input to the board and they are connected to P4 on the PCB then it's single voltage.

 Basically a single 24V cascode connects to P4 and the rail splitter converts that into 12V per channel (per rail). A stereo pair of cascodes will supply 12V to both left and right channels direct to P3 and will totally bypass the rail splitter (p4)......... in effect, it's two 12V power supplies (one for each channel) with each 12V supply going direct to each channel (P3 left channel / P3 Right channel) negating the need for a rail splitter.

 Mike.


----------



## FritzS

Hi,
 what your experience about Nichicon "fine gold" vs. Elna Cerafine vs. Blackgate (Rubicon) in PSU or in signal path?
 What type's are in orginal WNA MKII kit? What are the largest caps for C5, C6, C7, C11, C12 that I can replace the orginal without any problems in space and looks nice too


----------



## PinkFloyd

Quote:


  Originally Posted by *PinkFloyd* 
_email David and ask him or take a pic of the guts of your amps and post it, it's easy to tell....... you're cascode is probably single voltage connected to P4 running through the rail splitter..... if it's dual voltage it will bypass P4 (the rail splitter) and go direct to P3 (left channel) and P3 (right channel) if you open the amp up and follow the wires from the DC input to the board and they are connected to P4 on the PCB then it's single voltage.

 Basically a single 24V cascode connects to P4 and the rail splitter converts that into 12V per channel (per rail). A stereo pair of cascodes will supply 12V to both left and right channels direct to P3 and will totally bypass the rail splitter (p4)......... in effect, it's two 12V power supplies (one for each channel) with each 12V supply going direct to each channel (P3 left channel / P3 Right channel) negating the need for a rail splitter.

 Mike._

 

<Bing Bong> Cascode announcement:

 Heh, I wasn't far off the mark... but here's how you can power the WNA using the cascode:

Words by Dr. White.

 "As regards the cascode psu, the current model is two separate floating power supply channels which would each be set to 24V for use with a WNA headamp. The simplest connection is just to take the 24V from one psu channel and use this to power the headamp as normal, with the output from the headamp rail splitter driving both headamp channels. The second psu channel then remains unused. If you wish you can get another rail splitter pcb, connect this to the unused psu channel, and power each headamp channel from a different rail splitter output. The extra rail splitter pcb pretty much corresponds to what you would get if you sawed the rail splitter section off of a headamp pcb and added an extra couple of mounting holes."

 "Alternatively the psu can be configured for 15V outputs and the two supplies connected in series to give +15V/0V/-15V. You then ignore the rail splitter on the headamp pcb and connect the +15V/0V/-15V psu output to P3 on each headamp channel. So one +15V/0V/-15V supply is driving both headamp channels."


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Hi,
 what your experience about Nichicon "fine gold" vs. Elna Cerafine vs. Blackgate (Rubicon) in PSU or in signal path?
 What type's are in orginal WNA MKII kit? What are the largest caps for C5, C6, C7, C11, C12 that I can replace the orginal without any problems in space and looks nice too 
	

	
	
		
		

		
		
	


	


_

 

Hi Fritz,

 I've only tried the cerafines in the WNA to very good effect, I'll let you know how the fine golds sound as soon as I put together my WNA. I believe the kit comes supplied with 25V rubycon ZA caps.

 I wouldn't go any higher than 220uF in C5, C6, C11 & C12.. well, I did and it caused the inrush current to wipe out TR5 & TR6 and I3 & I4 in the rail splitter. If you mean large as in "size" then you can fit some quite large caps to C7, C11 and C12 but you are limited to pretty small caps in the C5 and C6 positions.. the 100uF 25V fine gold caps will "just" fit comfortably in C5 & C6 and they are pretty small caps..... if you've got a PCB you'll see what I mean about the space around C5 & C6.

 All the best.

 Mike.


----------



## PinkFloyd

All the bits and bobs have arrived so I'm now armed with the components to put another WNA together 
	

	
	
		
		

		
		
	


	




 I should get it built up this weekend. 

 I was hunting about in my parts box and came across some spare 220pF polyprop caps and some 100nF polyester caps which I've decided to parallel with the 100uF 'lytics...... may as well use them up...... I've always meant to try this but have never got around to it so I run this idea across Dr. White to get his take on it before trying it and here's his take on it:

"Quite a few people parallel their power amp smoothing caps with 1uF polypropylene and 100pF silver mica capacitors in order to compensate for the rising impedance of electrolytics with frequency and to minimise hf and rf noise. I haven't tried it but those who have claim a noticeable improvement. The impedance of all electrolytics rises fairly sharply with frequency, cheaper elcaps faster than premium grade ones. Your 220pF caps will reduce the impedance at very high frequencies and reduce hf/rf noise so there will be a beneficial effect. You could add a 1uF film cap of some kind as well to fill in the gap between the elcap and the 220pF polypropylene."

 This is not an official tweak but I'm willing to be a guinea pig and give it a go........ I will be using 220pF polyprops and 100nF polyester film caps paralleled with the 100uF 'lytics (quite simply as I have them at my disposal) if they work then I'll buy and try 1uF polypops and 100pf Silver Mica caps and parallel them with the 'lytics.

 Watch this space 
	

	
	
		
		

		
		
	


	




 Mike.

 EDIT:

 An idea of how to fit a cap in parallel:


----------



## BrokenEnglish

good idea, mike! i've done bypassing like yours (i used 82nf + 22nf fkps) with my 1000µf adventures and got noticeable improved, tighter bass response with clearer mids before the transistors burned (again, friends: don't use 1000µf caps in the railsplitter!). i'll return to this cap-arrangement with my dual psu (hopefully the connectors will arrive tomorrow)...


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_good idea, mike! i've done bypassing like yours (i used 82nf + 22nf fkps) with my 1000µf adventures and got noticeable improved, tighter bass response with clearer mids before the transistors burned (again, friends: don't use 1000µf caps in the railsplitter!). i'll return to this cap-arrangement with my dual psu (hopefully the connectors will arrive tomorrow)..._

 

Hi Udo,

 It appears that 1uF polyprops and 100pF silver Mica is the best combo to parallel with the 100uF 'Lytics but there's no harm in me trying my 220 puff polyprop / 100nF polyester combo which I have to hand....... 

 Mike.


----------



## BrokenEnglish

yeah... go on, mike.. 220µf certainly should be no problem.. 
 i'll send you some more stuff for your trials next week...


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_yeah... go on, mike.. 220µf certainly should be no problem.. 
 i'll send you some more stuff for your trials next week... 
	

	
	
		
		

		
			



_

 

220pF (picofarad) not 220uF (Microfarad) Udo


----------



## BrokenEnglish

sh**.... ah... sorry... 
	

	
	
		
		

		
		
	


	




 ...no objections though...


----------



## PinkFloyd

I'm "really" looking forward to this build...... virgin pads and so much to play about with 
	

	
	
		
		

		
		
	


	




 Mike.


 EDIT: Udo, get yourself a MKll board man, we can exchange notes.


----------



## BrokenEnglish

stop tempting me, british devil... 
	

	
	
		
		

		
		
	


	




 ...i could get weak... 
	

	
	
		
		

		
		
	


	






 what pcb will you use, mike: pot & jack onboard?


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_stop tempting me, british devil... 
	

	
	
		
		

		
		
	


	




 ...i could get weak... 
	

	
	
		
		

		
		
	


	






 what pcb will you use, mike: pot & jack onboard?_

 

Yes, pot and jack onboard


----------



## PinkFloyd

The board arrived today and I spent a couple of hours populating it this evening, I've just got to hook up a zobel network and add a few more bypass caps and she'll be ready for casing up.... I _was_ going to take my time building it but I'm missing my WNA so much that I decided to get this one up and running ASAP.

 I've gone all polypropylene on this one but will be adding some WIMA polyester caps (220nF) to complement the 220pF EVOX polyprop bypass caps fitted on the underside of the board:






 I'm more of a polyester man myself (kinky 
	

	
	
		
		

		
		
	


	




 ) and this will be the first polyprop WNA MKll I've made..... it'll be interesting to listen to polyprops in the amp, I hated the polyprop sound in loudspeaker crossovers but they may sound better in an amp (fingers crossed) I love listening to different capacitors and, believe it or not, it was the sonic differences between capacitors that got me into this hobby.... I just love them and am fascinated by them.... great little devices.

 The "fine gold" caps _look_ nice, let's hope they sound good too! They looked so good that I decided to rename the "nitai" cap "fine silver" this involved removing the plastic wrap and polishing their butt naked bodies with Brasso and buffing them with a lint free cloth (yeh, call me sad I don't care!) I think they look good alongside the "fine golds":






 Well, the proof of the pudding is in the eating and I will report back with my findings once the amp is up and running.... onwards and upwards, fresh pads to play about with 
	

	
	
		
		

		
		
	


	














 The "pictorial guide" won't be happening on this occasion, I'm in too much of a hurry to get another WNA up an running _fast_ and feed my ears with some decent sound.....

 Mike.


----------



## BrokenEnglish

very nice, mike... also very tempting... rrrgg... must resist.... 
	

	
	
		
		

		
		
	


	



 the only thingies i don't like in there are those input caps... you know... 
	

	
	
		
		

		
		
	


	




 .... maybe your source needs them? hey... the "fine silver" look great!


----------



## PinkFloyd

How can you resist? Impossible to resist!! I fit input caps as I use the amp with three different sources one of which adopts a DC servo system..... I prefer the safety net (cap) on board but others prefer no input / output caps....... I'm sending you a couple of bourns 100K trimpots and 10M resistors (as well as a few other goodies to try Udo) let me know how your cap free WNA sounds (I doubt you'll hear a difference)

 I'll be trying the capless WNA with my CD-17 in due course but as the WNA is a kit it has to work with "every" source and "every" headphone as a matter of course........ it has to be bullet proof and I am reporting on the kit "as is" (with input and output caps in place) all the mods I have mentioned assume that input / output caps are in the circuit........ Remove the input / output caps at your own risk, the input caps are not necessary if your source has minimal offset but I would strongly recommend you keep to the kit recipe when it comes down to output caps.

 I prefer output caps to trimpots they guarantee "nil" DC offset... of course it's up to you and anything you do outwith the recommendation is at your own risk 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## BrokenEnglish

mike... i've stocked the appropriate 100k precision trimmers and also the 10M resistors some weeks ago. but i have to stick with output caps as long as i'm in the process to try different psus in order to override the railsplitter (just my personal obsession - most likely nothing, that really matters... 
	

	
	
		
		

		
		
	


	




 ). 

 but be assured... the difference in sound with vs. without _input_ caps is huge... at least given polyester caps there. drawback: chances are, you'll get some crackling noise while turning the volco... 
	

	
	
		
		

		
		
	


	




 but who knows... maybe some decent polypropylene caps (like yours) are the way to go...


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_but be assured... the difference in sound with vs. without input caps is huge... at least given polyester caps there. drawback: chances are, you'll get some crackling noise while turning the volco... 
	

	
	
		
		

		
		
	


	



_

 

DC


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_DC_

 

right...


----------



## PinkFloyd

refit the input caps but mod the output using the 100K trimpot and 10m resistor.


 Mike.


----------



## BrokenEnglish

my route:
 1. psu-tests
 2. fit 10m ohm resistors /100k trimmer: if volco-crackling stays, goto 2a
 2a. fit 4,7µf mcaps (polypropylene... on their way 
	

	
	
		
		

		
		
	


	




 )
 3. check the sound without output caps


----------



## PinkFloyd

That's her up and running and I'm so happy to have the WNA sound pampering my eardrums with detail and glorious sound once again 
	

	
	
		
		

		
		
	


	




 It's too early to tell but the polyprops seem to give a smoother overall presentation to the sound (compared to polyester) and this really does suit the Grado SR325i.... I'm not sure I like the extra smoothness with the HD-600 but, as I say, It's early days and the amp has only been up and running for about 3 hours.

 She fired up first time no problems at all so it really does look like the MKll is pretty much bullet proof and well protected from the oscillation God unlike MKl which _could_ play up from time to time and was pretty sensitive to certain caps and long cable runs.

 I decided to keep the internal wiring short and tidy in this amp so didn't fit an On / Off switch or a LED on the fascia..... I keep the amp switched on all the time anyway so an On / Off switch is unnecessary and a fascia mounted LED equally unnecessary. (more wire) I fitted a 5mm LED direct to the board (the LED pads) and will probably cut a hole out of the top cover of the amp and glue in a bit of perspex which will illuminate the amps innards on dark nights:






 The amp looks plain ugly in the Hammond enclosure (or minimalist, whatever you want to call it) and I think a 30mm round perspex peephole in the top would give it a bit of panache.

 Ugly or what?






 Thing is, it sounds _awesome_ and that's the main thing..... it's easy to tart up the looks further down the line but the sound is the most important part and boy it's sounding good now (it's been two hours since I started this post and I've been back and forth to the toilet swilling out with ice cold water to alleviate excruciating toothache) I've just popped my 'phones on again and the amp is burning in nicely with the sound opening up and filling out.... Unfortunately the toothache is getting worse and not responding to _anything_ other than 30 second "swills" of ice cold water so I'll cut this thread short and save my energy for a weekend of pain management.

 I'll report back on the bypass caps etc. once I can fully concentrate on the amp (once I get this pig of a tooth removed!) In the meantime... MKll seems pretty much bullet proof and plug and play and, as such, gets a big thumbs up from me...... the kit is a breeze to put together and a lot more tidy than the MKl:





 MKll





 MKll





 My first ever WNA MKl (a true wirefest 
	

	
	
		
		

		
		
	


	




 )

 Things have certainly evolved since the MKl.... let's hope Dr. White continues to hone this fantastic amp, it's a beauty.

 Mike.


----------



## BrokenEnglish

tight and nice build, mike... as always... i'm sure, besides dr. white there's no one out there who has built more wna has than you. i like your minimalistic approach.... and of course that red led.. 
	

	
	
		
		

		
		
	


	



 i guess, you've fitted most of the tweaks (330k, qc up)? but i couldn't find the zobel net. i'm sure, you'll spend some coolers to the transistors. 

 but first of all, mike, i hope you'll cope with that screw*** toothache.... my best wishes!


----------



## Madcat05

Looks like a very nice build Mike. 

 I've been following the MKII thread for awhile and it'll be interesting to hear your impressions of your latest build.

 Cheers.


----------



## BrokenEnglish

btw.. i'm thinking about tantalums as replacements for c5/c6. in theory they should be a better solution than the best electrolytics there. has anybody actually tried this?


----------



## bludragon

Well, before trying any of the recommended tweaks, I decided to take some measurements using RMAA and an e-mu 0404 sound card.
 Going by these it would seem that the 1st thing to change is to add a zobel, and remove the output lamp (R11).

 Without a load the performance didn't degrade much from the sound card looped back to itself without the amp in place.

 With a load however (a pair of HD650's), there was significan distortion at lower frequencies, and some small amount of IMD. As an aside a resistive load had a much lower 2nd order harmonic than the headphones.

 Adding the 330K feedback resistor didn't change things.

 Adding the zobel, and removing R11 (the incandesant bulb) helped significantly.

 The 2nd harmonic at 60Hz dropped from -60dB to -85dB, the 3rd from -74dB to -101dB.
 IMD dropped from having distortion products at -91dB and -110dB to -126dB and -120dB.

 So there you have it. Bear in mind that these measurements could be affected by a bunch of things, not least my neck around which the hd650's were hanging


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_i guess, you've fitted most of the tweaks (330k, qc up)? but i couldn't find the zobel net. i'm sure, you'll spend some coolers to the transistors. _

 

Hi Udo,

 Yep, fitted the 330K but have not upped the QC (hence no heatsinks) I'm going to live with standard QC for a while and then up the QC at a later date... this will give me a better idea of what it does to the sound.

 Zobel is fitted on the underside of the board.... it's basically just a 100nF cap and 10R resistor in series connected across the amp side of the output cap and ground....... it makes a big difference to the sound quality / measurements Udo.


















 Mike.


----------



## BrokenEnglish

hey... nice layout, mike... lots of bypassing there - i like it. just forgot to send you a pack full of small-value fkps... they'll round up the colours there nicely... 
	

	
	
		
		

		
		
	


	




. give me another 2 weeks... 
 what are those extra-cables from the pot to somewhere for? 
 /edit: or is it the headphone jack? extra wiring from out to jack? thought, that wouldn't be necessary with those onboard-pcbs... 
	

	
	
		
		

		
		
	


	




 hope you're back on stage, mike. all the best to YOU and your tooth!
 udo


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_hey... nice layout, mike... lots of bypassing there - i like it. just forgot to send you a pack full of small-value fkps... they'll round up the colours there nicely... 
	

	
	
		
		

		
		
	


	




. give me another 2 weeks... 
 what are those extra-cables from the pot to somewhere for? 
 /edit: or is it the headphone jack? extra wiring from out to jack? thought, that wouldn't be necessary with those onboard-pcbs... 
	

	
	
		
		

		
		
	


	




 hope you're back on stage, mike. all the best to YOU and your tooth!
 udo_

 




 All that wiring is necessary and is the "wiring" I've been going on about for the past year......... the sooner that wiring can be dispensed with, the easier the amp will be to build and that's good news for everybody.

 Mike.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Zobel is fitted on the underside of the board.... it's basically just a 100nF cap and 10R resistor in series connected across the amp side of the output cap and ground....... it makes a big difference to the sound quality / measurements Udo.



_

 

Hi PinkFloyd
 what type's are the other blue an red caps?
 what value they have?


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Hi PinkFloyd
 what type's are the other blue an red caps?
 what value they have?_

 

Hi Fritz,

 The little blue bypass caps are 220pF EVOX Rifa polyprops and the red ones are WIMA MKS4 (100nF for the zobel network)

 The one small red cap in the rail splitter is a WIMA 200nF K5. There's no rhyme or reason for this and I am just experimenting with bypass caps....... I'll probaly end up bypassing the 100uF electrolytics with a 220pF silver Mica and a 1uF polyprop.

 I'm slowly building up a picture (and taking notes) of the differences (not necessarily improvements) with the bypass caps in situ and will experiment with a few more combinations before posting.

 One thing I have noticed......... I can't listen to the HD-600's with polyprop caps..... they sound way too chocolaty and distant....... the Grado SR325i sounds excellent with the polyprops.. sharp, attacking, hyper detailed yet comfortably listenable. It could be that I prefer the SR325i to the HD-600 but I can't remember the HD-600 sounding so mushy and syrupy through any of my many previous WNA amps .... they just sound plain _boring_ and _lifeless_ driven by the polyprop WNA (nice sound but a jack of all trades and master of none sound)...... as I say, It could be the case that the SR325i is better suited to my ears but I suspect it's due to the polyprop caps........... polyprop has always sounded rubbery and artificial to me, I understand why people like them in audio circuits...... they have a tendancy to warm the sound down a tad and present you with a "comfortable" inoffensive listen.

 I may be barking up the wrong tree here but, at the time of writing, I don't like the sound of the WNA with the polyprops in circuit........ it's as if someone has coated my eardrums with rubber........ sounds way too quacky, honky and smeared with the HD-600 yet, strangely, the sound is inch perfect through the SR325i.

 I've got a cartload of polyester caps and will try them out and compare them to the polyprops....... at the present time it's the case that either the SR-325i sounds miles better than the HD-600 or the polyprops don't sound as good as the polyester....... it _could _ be a headphone thing but the fact the HD-600 sounds so lifeless and unexciting driven by the polyprop WNA has me pointing my finger at the polyprop caps.

 I'll report back once I've experimented with a few different caps and once my tooth has been fixed.

 Mike.


----------



## spendorspain

Hi 

 I’d like to post my opinion on 330k mod because it’s different. My modded WNA hp amp sounded great, as I said in my previous post, but as listening hours passed I began to feel a certain loss of extreme highs, like a subtle but noticeable filtering of the “air” of the recordings. It appeared only after a long (two months!) break-in period when, I guess, the sonic personality of the new components fully developed. Perhaps there was simply a mismatch between the modded amp and my very mellow-sounding audio system (Meridian 206DS CD, Van den Hul “The First” carbon cable and Grado HP-2 with flat earpads, which reportedly sound a little dark and very different to the brighter RS-1 or SR-325). Looking for an explanation, I searched the Web and read a lot of posts in this and other forums. All info pointed to the 330k resistors because several head-fiers described this mod as “smooth sounding” or giving more “soul and warmth” to 6171 IC (perhaps the Grado HP-2 have “soul” enough on their own 
	

	
	
		
		

		
		
	


	




 ). Moreover, I’d used AudioNote tantalum resistors, also said to have a sweet sound. So, I decide to open the case and unsolder them, with amazing results. The highs went back and the missing air and space are there again without any audible side-effects in the rest of frequency range. I’d like to know if somebody have similar experiences with the 330k mod, although perhaps it’s only a mismatch with my own system.

 Regarding the last post of Mike and others from Udo, and my own preference for a very open and transparent sound, I’m thinking about removing the polypropylene input caps to see (hear?) if this improves the sound, but I’d like to do that in a safe way. Could you explain how to measure DC offset at output of CD player with a voltmeter? I suppose I have to touch the inner tube ("live") of RCA socket with the red probe and the outer ring ("ground") of socket with the black probe, in both channels and with my multimeter set to measure mV DC (in my case in its "< 2V DC" setting ). Is this correct? Is the measurement made with music playing or perhaps in "pause"?.
 What would be a safe value of DC offset, if present, in order to connect the CD player to the WNA hp amp with no input capacitors? Can this value drift in certain circumstances (e.g.: be a safe value today but larger and dangerous in other moment)?

 I’d also like to comment the musical results of using a WNA Cascode PSU instead of the switching-mode “wallwart” supplied as standard. As “1up” and “Captain” have said before, it is worthwhile. It improves dynamics and detail, lowers the noise almost to inaudibility and makes big orchestral climaxes clearer and effortless. The sound is more natural, realistic and “free”. Now, without the 330k resistors and with Black Gates output caps and the Cascode PSU, the WNA amp sounds better than ever… until the next upgrade arrives (perhaps the removal of input caps or the increase of quiescent current of output transistors).

 As always, I’m afraid this post is too long, but I hope you can explain the doubts I have.

 Regards,
 Jose


----------



## PinkFloyd

Quote:


  Originally Posted by *spendorspain* 
_Hi 

 I’d like to post my opinion on 330k mod because it’s different. My modded WNA hp amp sounded great, as I said in my previous post, but as listening hours passed I began to feel a certain loss of extreme highs, like a subtle but noticeable filtering of the “air” of the recordings. It appeared only after a long (two months!) break-in period when, I guess, the sonic personality of the new components fully developed. Perhaps there was simply a mismatch between the modded amp and my very mellow-sounding audio system (Meridian 206DS CD, Van den Hul “The First” carbon cable and Grado HP-2 with flat earpads, which reportedly sound a little dark and very different to the brighter RS-1 or SR-325). Looking for an explanation, I searched the Web and read a lot of posts in this and other forums. All info pointed to the 330k resistors because several head-fiers described this mod as “smooth sounding” or giving more “soul and warmth” to 6171 IC (perhaps the Grado HP-2 have “soul” enough on their own 
	

	
	
		
		

		
		
	


	




 ). Moreover, I’d used AudioNote tantalum resistors, also said to have a sweet sound. So, I decide to open the case and unsolder them, with amazing results. The highs went back and the missing air and space are there again without any audible side-effects in the rest of frequency range. I’d like to know if somebody have similar experiences with the 330k mod, although perhaps it’s only a mismatch with my own system._

 

The 330K certainly does "warm" the sound up a tad giving the impression of a smoother overall sound with deeper bass and more musicality overall. Yes, you _do_ trade off a bit of air (everything in audio is unfortunately compromised by one thing or another, you generally can't have your cake and eat it) but you benefit as the LM6171 becomes less sterile, clinical and analytical. I liked the 330K mod when I was using polyester caps in my last amp (the 100nF ones) but, as I say in the post above, the sound with the 330K _and _ polypropylene caps in place doesn't have the same bite and grunt as the amp with polyester caps and 330K did.

 My newly acquired SR-325i may be throwing me off course a little here but I distinctly remember them as sounding pretty forward and aggressive with my last (WNA fitted with polyester caps and 330K) with the new WNA (polypropylene and 330K) they sound beautiful.... a match made in heaven.

 However my HD-600's, which sounded _perfect_ driven by the polyester / 330K WNA now sound slightly rolled off and positively syrupy driven by the polypropylene / 330K latest WNA..... so, yes, I totally agree that the 330K plays quite a big part in the sonic signature of the amp but so do the 100nF capacitors! 330K and polyester gave perfect synergy with the HD-600 whereas 330K and polypropylene makes them sound _too_ chocolaty. 330K and polyester made the 325i's sound forward, aggressive and "toppy" whereas 330K and polypropylene make them sound absolutely heavenly. 

 It's a weird old game but the beauty of DIY is that you can tune the amp to your own requirements....... I'll be trying the WNA without the 330K but with the polyprops in place this weekend..... I've got a feeling the combo of polyprop _and_ 330K may account for the "smoothness" with the HD-600 but I don't wan't the SR 325I's reverting back to sounding "in yer face" at the same time, I love the WNA / HD 6** combo and would like to get good synergy with _both_ the Grado and Sennheiser 'phones........ a good challenge for the weekend! 



  Quote:


  Originally Posted by *spendorspain* 
_Regarding the last post of Mike and others from Udo, and my own preference for a very open and transparent sound, I’m thinking about removing the polypropylene input caps to see (hear?) if this improves the sound, but I’d like to do that in a safe way. Could you explain how to measure DC offset at output of CD player with a voltmeter? I suppose I have to touch the inner tube ("live") of RCA socket with the red probe and the outer ring ("ground") of socket with the black probe, in both channels and with my multimeter set to measure mV DC (in my case in its "< 2V DC" setting ). Is this correct? Is the measurement made with music playing or perhaps in "pause"?.
 What would be a safe value of DC offset, if present, in order to connect the CD player to the WNA hp amp with no input capacitors? Can this value drift in certain circumstances (e.g.: be a safe value today but larger and dangerous in other moment)?_

 

I always check DC offset from the source at the input of the amp with a CD in the CDP on pause. Set your voltmeter to DC and onto the 200mV range. Probe the phono socket (inside your amp) thus:

 Black probe (com) to phono socket ground and red probe (V) to phono socket signal...... IMO anything under 25mV is acceptable and you're safe to dispense with input caps (jumper over C1) My CD17 measures 0.00mV on both channels though my Denon CDP measures 4.1mV L/H & - 2.1mV R/H both are ok to use the amp without input caps (as are the vast majority of CD sources) 

 The WNA kit _only_ employs input caps to make it bullet proof for use with _every_ source under the sun..... there may be 2% of sources that output DC so the caps are fitted as a "better safe than sorry" measure..... a bullet proof safety net if you like. Sure the amp will sound a lot better without them in the circuit but check your sources offset before binning them. 

 Another thing you may want to try is replacing the 47K input resistor with a 10K resistor. Dr. White commented on this on the MKl and I quote:

 * "Lowering the input impedance to 10k will give ( theoretically ) lower noise and will also reduce the output offset with the LM6171, but not enough so you can dispense with the output caps. The component values that I choose for my designs are a compromise which will work satisfactorily with the widest range of attached equipment. I generally use 47k input impedance because that'll pretty much work with anything. For my personal stuff I always use 10k. That's the beauty of DIY you can tweak your gear to suit yourself." * 

 You'll note Dr. white also says " The component values that I choose for my designs are a compromise which will work satisfactorily with the widest range of attached equipment" in 99% of cases it's probably perfectly OK to dispense with input caps and use 10K input resistors etc. He's providing a kit which has to work first time every time with _all_ equipment.......

 It's not for me to suggest you remove these safety barriers but the performance of the amp is certainly a lot better with them removed but, if you do decide to remove them, ensure your source has minimal DC (only really crap / obsolete / faulty gear will have a massive DC output.... 99% of it should be fine 
	

	
	
		
		

		
		
	


	




) 

 As to the Output caps..... I'd recommend leaving them in........ I tried the 10M resistor and trimpot and couldn't hear a lot of difference but the input caps are well worth removing 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *spendorspain* 
_I’d also like to comment the musical results of using a WNA Cascode PSU instead of the switching-mode “wallwart” supplied as standard. As “1up” and “Captain” have said before, it is worthwhile. It improves dynamics and detail, lowers the noise almost to inaudibility and makes big orchestral climaxes clearer and effortless. The sound is more natural, realistic and “free”. Now, without the 330k resistors and with Black Gates output caps and the Cascode PSU, the WNA amp sounds better than ever… until the next upgrade arrives (perhaps the removal of input caps or the increase of quiescent current of output transistors)._

 

I must get round to auditioning a cascode PSU, sounds good, I'm still using the linear open frame calex PSU and it rocks my boat 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *spendorspain* 
_As always, I’m afraid this post is too long, but I hope you can explain the doubts I have._

 

No post is too long when It's interesting Jose and your first three posts have been very interesting and informative.... please keep them coming 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


----------



## spendorspain

Hi

 As you’ve said, one of the beauties of "DIY" is the posibility of fine tuning the equipment to the rest of system and to personal tastes. More fun! 
	

	
	
		
		

		
		
	


	




 I have just received the schematic of my 206DS CD player from Meridian Audio (see image attached to this post) and I've measured the DC offset at RCA outputs. I have read in my multimeter a DC voltage between 0.000 and 0.001 volts in both channels but I can't see an output capacitor in series with the RCA socket to blocking DC. In other forum I've been told that the resistors between the 5534 op-amp and the output transistors are precisely for nulling any offset but I'm still concerned about the possibility of drifting in these values (although 1mV is very low). What do you think about this? Is there any situation that can induce an anormally increased DC offset? 

 However, as I'm going to keep the output caps (very high quality Black Gates) in the amp, I guess the headphones are always protected from DC in any circumstance (am I right?)... So, I have removed the input caps 
	

	
	
		
		

		
		
	


	




 and fitted a silver wire jumper in their place. A great advantage of evaluating the removal of components (instead of the adding) is that there is no "burn-in" time and the effects can be heard inmediately (and no week or even months later). From the minute one, the input capacitor-less WNA amp sounds vastly better. To put it shortly (and at risk of falling in a commonplace) this mod takes away a veil that previously was between the musicians and me, although I wasn't aware of it before its removal. It is, by far, the biggest improvement to date in my WNA amp (and the cheaper!)

 Drawbacks? Only a very minor and I hope not worrying: when I rotate the volume control fully counterclockwise (I always do that before turning the amp off or when changing interconnects) there is a faint crackling, but only at the very end, never in the useful range of pot. I now simply stop their rotation a little before it ends (anyway, at this point the sound level can be -60/70 dB, I guess).

 I'm afraid the WNA amp is becoming addictive... 
	

	
	
		
		

		
		
	


	




 Regards
 Jose


----------



## PinkFloyd

Quote:


  Originally Posted by *spendorspain* 
_Hi


 I have just received the schematic of my 206DS CD player from Meridian Audio (see image attached to this post) and I've measured the DC offset at RCA outputs. I have read in my multimeter a DC voltage between 0.000 and 0.001 volts in both channels but I can't see an output capacitor in series with the RCA socket to blocking DC. In other forum I've been told that the resistors between the 5534 op-amp and the output transistors are precisely for nulling any offset but I'm still concerned about the possibility of drifting in these values (although 1mV is very low). What do you think about this? Is there any situation that can induce an anormally increased DC offset?_

 

You're fine using the Meridian without input caps, I believe the 206 uses an LF353 op-amp somewhere in the circuit which provides a DC-servo action so you're ok 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *spendorspain* 
_However, as I'm going to keep the output caps (very high quality Black Gates) in the amp, I guess the headphones are always protected from DC in any circumstance (am I right?)..._

 

You are correct 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *spendorspain* 
_ So, I have removed the input caps 
	

	
	
		
		

		
		
	


	




 and fitted a silver wire jumper in their place. A great advantage of evaluating the removal of components (instead of the adding) is that there is no "burn-in" time and the effects can be heard inmediately (and no week or even months later). From the minute one, the input capacitor-less WNA amp sounds vastly better. To put it shortly (and at risk of falling in a commonplace) this mod takes away a veil that previously was between the musicians and me, although I wasn't aware of it before its removal. It is, by far, the biggest improvement to date in my WNA amp (and the cheaper!)_

 

I too removed my input caps earlier on and replaced them with axial lead ferrite bead inductors and all I can say is [size=large]*WOW!!!* [/size] I didn't have input caps in place with the MKl and don't know why I fitted them in the MKll but removing them brings about a _vast_ improvement to _everything_ across the spectrum.

 The input caps were certainly muffling the music, with them removed not only is there a lot more clarity and detail but the timing has improved as well..... not subtley but very noticeably.... this has to be _the_ best WNA I have ever heard and I can see me hauling out all of my CD's to rediscover them through the input cap free WNA this weekend.... 

 It's a revelation with the caps removed and my jaw dropped to the floor when I listened to a couple of my very well known test tracks (I know them like the back of my hand) My god "planet dada" (from YELLO "the eye" album) sounded _completely_ different I really was / am shocked! The rhythm, the timing and the entire "tune" is now presented totally differently.... where before the bass line sounded as though it was bam bam bong It's now de bap a boo bam de bap a boo bam..... "everything" is now perfectly syncopated and this particular tune now makes a lot more sense both rhythmically and musically.... with the input caps in place this same track sounded to me as if YELLO had lost the plot with this album but with them removed this track makes a _lot_ more sense musically and every element of the sound comes together perfectly...... total magic!

 As I type this I've got Mike Oldfield's Tubular Bells playing and (jesus H christ) I can't remember it sounding as exciting as this and I have been listening to it through a variety of equipment since the first day it was released back in the 1970's..... there are elements in the mix that I have never before heard and they are being delivered to my ears in copius amounts.... I don't usually over enthuse when it comes to audio but (excuse my p's and q's) this is ******* incredible stuff!!

 What Hell of a swamp has my brain been drowning in this past year that it didn't receive the oxygen to make me think "remove the input caps" ??? I never used them with the MKl (which is why I probably remember the MKl with fondness) When I first tried the MKll I built the kit "as per the manual" and, quite honestly, rested on my laurels and couldn't be arsed messing about with it... it sounded "good" and that was good enough for me.... sure I tried Dr. White's 330K mod etc. but my enthusiam for anything Hi-Fi was at a life time low as was my enthusiasm toward _life_ in general.... what with severe bouts of toothache, cluster headaches and a general accompanying feeling of doom and gloom It's no wonder I'd lost my enthusiasm and, at times, the will to live.......

 Well, enough of that.... the birds are singing and the sun is shining and the input caps are removed 
	

	
	
		
		

		
		
	


	




 I was honestly not expecting too much of a gain in quality by removing them but am pleased to report that, yes, the improvement is enormous...... It's like listening to a new amp...... The HD-600's have perked up and the SR-325i still sound glorious so It's a win win situation all around.

 If the sound should get so much better with the removal of the input caps then the same should hold true for the output caps.... I'll remove the output caps tomorrow and report back with my findings.......... I can mount the 100K trimpots where the input caps used to sit so I don't have the excuse of "there's no room on the board" anymore....... the output caps will be removed tomorrow.

 This input capless amp is exciting my ears so much that I'm off to re - explore my CD collection..... I'll be back.

 Mike.

 EDIT: I'd written 10 times more than the above 
	

	
	
		
		

		
		
	


	




 and Head-Fi had one of its moments and I lost the entire post 
	

	
	
		
		

		
		
	


	




 I must remember to do my write ups "offline" and then copy and paste them in........ It's tragic when you spend an hour typing and the entire post disappears before your eyes 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *spendorspain* 
_Drawbacks? Only a very minor and I hope not worrying: when I rotate the volume control fully counterclockwise (I always do that before turning the amp off or when changing interconnects) there is a faint crackling, but only at the very end, never in the useful range of pot. I now simply stop their rotation a little before it ends (anyway, at this point the sound level can be -60/70 dB, I guess).
_

 

I've had the same thing with a couple of WNA amps It's not a problem but annoying nonetheless.

 Try the following:

 Wear a pair of rubber gloves and rotate the Volco to zero end stop....... if the crackling disappears either fit a plastic volume knob or ground the aluminium potentiometer housing to 0V......... It "only" happens if you are using a metal volume knob _and_ touching the knob at the time?

 There are a few workarounds for this scenario but I need to know whether the crackling disappears with rubber glove first...... If not then I know what's causing it.

 Mike.


----------



## Alick

Like you Mike, I fitted input cap's to my Mk II although I had omitted them from the Mk 1. After reading your post, I'm planning to short them out tomorrow. I'll report back.


----------



## PinkFloyd

Phew! What a weekend that was, almost all of it spent trying to get the LM6171 to work without input / output caps.... to cut it short you can use the LM6171 with 10M resistor and trimpot only if you leave the input caps in place.... Dr. White explained what was going down but I'm too tired to type it all out but basically with the input "and" output caps removed the LM6171 measured a very low 4mV offset (without the 10M resistor and trimpot fitted) I thought this was excellent and thought I must have got a couple of really closely matched LM6171's with very low offset..... nope, not as simple as that... as soon as I turned the volco clockwise the DC offset started to rise and at fully clockwise position the offset was very high... as I say, something to do with the input caps being removed and once I get the explanation / reason I'll post it.

 It turned out to be a blessing in disguise, however, as the amp was input / output cap free I thought I'd roll in a few other opamps as I've never heard other opamps in a totally cap free WNA.

 OPA627..... in a word "awful"..... to give it the benefit of the doubt I removed the 330K between 2&6 of IC1...... still awful.... bland, dark, mushy and tuneless.

 So it was out with the OPA627 and in with the AD843...... Ladies and Gentlemen, allow me to present to you my new favourite opamp..... please give a hand for the AD843!






 I enthused about this chip a while ago, before the LM6171 330K mod, and it sounded pretty good then but with the input and output caps removed _and_ a 32V supply it sounds exceptional.... far better than the input cap free LM6171 IMO...... gorgeous deep bass, better definition (instruments better defined than with LM6171) in fact it does everything better and no need for input / output caps or DC trimming resistors.

 Just read my original impressions of the AD-843 and then add 40% improvement onto that and you'll get the idea of _just _ how perfect this opamp sounds to my ears.... there's no doubt that the LM6171 is a very fine sounding opamp but it's not in the same class as the 843 running without input / output caps... the detail of the 843 at the _lowest_ volume setting is amazing..... you get the impression that the headphone drivers are really shifting tons of oxygen and that's with the volco just off the 7 o' clock position...... no need to notch the volco up to mid / loud levels to hear every last detail with the 843 but when you _do_ crank the level up a few notches you're in for something pretty special. I always classed a pair of loudspeakers as "good" if they could convey the same detail at very low volume levels as they could at medium levels... why should headphones be different..... the 843 can deliver the goods at the lowest of volco settings.

 It certainly likes voltage and upping my calex PSU from 24V to 32V reaped rewards (more of everything!) so if anyone is considering trying it with the WNA then 24V is gooood but 30V is optimal (my PSU adjusted to 32V)

 At last! a cap free WNA _and_ an opamp that makes seriously good music.... there's _no way _ I'll be mucking about with the LM6171 from here on in..... no way........ It's got too many limitations for my liking and I don't like its prima donna nature...... if it sounded _fantastic_ then maybe I could live with its erratic behaviour patterns but, as it stands, it has served its time in my amp and has now been replaced with an AD843 which IMO sounds truckloads better than the LM6171 ever did..... and that's a directly rolled in 843 (circuit not optimised for it) with no input / output caps in sight...... It can only get better! 

 LM6171 is out the window but I _am_ interested by a recent entry in my website guestbook:

 *" Have you tried the composite configuration of the AD744 and the AD811 as described in Audio Amateur/Audio Electronics and designed by Walt Jung of Analog Devices? The best I've ever used as a pre amp line driver or a head phone driver. Other op amps can be used with the AD811 if you prefer and use caution to make sure the phase margin and bandwidth is compatible." *  

 I haven't tried it but sure want to try it! I contacted Dr. White regarding this question and got the following reply:

* "I designed a little adaptor pcb to implement this idea a few weeks ago. You use surface mount opamps, one on top of the pcb and one on the bottom. Then you just plug it into the WNA in place of the LM6171."  *

 I'm not sure if he has got any adaptor PCB's for sale but will ask.... would anyone be interested? 

 Right, enough typing, I'm off to have a long session with the 843WNA......... I could be gone a long time 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.





 Cap Free at last!!! 





 Free at last.


----------



## 12796

Pinkie,

 Hi - by curious conicnidence I need a 32V supply. What are the details for yours? Sounds like I should be subbing in the AD843 for my preamp and headamp ASAP. The latter is still with WNA 
	

	
	
		
		

		
			





. 

 Regards,

 Nick.


----------



## 12796

Yes I am interested in the composite's - it's one of the things I have been discussing with Dr White for some time. It would be great to have someone else checking out a few combinations too!


----------



## Alick

Sounds very interesting Mike. I'd like to try the AD 843s. I see no heatsinks in your picture. Does that mean you're running with the original QC settings? Any plan to try the AD 843 with the higher QC setting? Where did you buy the AD843s?
  Quote:


 I'm not sure if he has got any adaptor PCB's for sale but will ask.... would anyone be interested? 
 

I'd be very interested in buying a pair of adapters.


----------



## 12796

RS doesnt seem to stock the ad843 - any recommendations of where to buy it?

 Nick.


----------



## bludragon

The ad843 appears to be available at farnell. I'm tempted to try it, but I'm wondering if I should try the 6171 without output caps first (but keep the input caps)...


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Sounds very interesting Mike. I'd like to try the AD 843s. I see no heatsinks in your picture. Does that mean you're running with the original QC settings? Any plan to try the AD 843 with the higher QC setting? Where did you buy the AD843s?_

 

Hi Alick,

 I haven't upped the QC so no need for heatsinks. The 843's ran as hot as toast in the higher QC WNA but with standard QC they run pretty cool. I didn't buy mine, got them as a sample from AD...... not too sure if you can actually buy them in the UK 
	

	
	
		
		

		
		
	


	




 Mike.

 EDIT: Maybe Dr. White can source them, must ask.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Pinkie,

 Hi - by curious conicnidence I need a 32V supply. What are the details for yours? Sounds like I should be subbing in the AD843 for my preamp and headamp ASAP. The latter is still with WNA 
	

	
	
		
		

		
		
	


	




. 

 Regards,

 Nick._

 

Hi Nick,

 Mine is a 24V "calex" open frame linear PSU from rapid but you can adjust the output and, surprisingly, mine can be adjusted from 23V to 31.6V which isn't at all bad 
	

	
	
		
		

		
		
	


	




 I'll type more on the AD843 soon Nick. I'm, quite literally, sitting here swilling and spitting whisky and applying a frozen crumpet to my cheek in a futile attempt to kill the pain that's emanating from the "stump" of tooth the dentist failed to extract (half the tooth is still in my mouth with the nerve exposed) I was referred to the dental Hospital and they sent me an appointment for "September" so it looks like I'm in for months of excrutiating pain or will be appearing in the newspapers "Wild man holds gun to dentists head and demands an extraction" It's almost reached that point...... I can't take any more of this continual agony.... looks like I may be forced into going back to the dentist who made a pigs ear of the extraction in the first place and suffer further trauma from him wielding his chisel in my mouth.... he's more than happy to do it "immediately" as he's well aware that the original extraction was a total balls up and me appearing at the dental Hospital with a tooth in this state would not bode well for his reputation.

 It's a case of suffering "agony" until September or going back to him tomorrow....... I've held out for two weeks but I can't do this pain for 4 months..... principle is out of the window, I can't endure the slow torture a minute longer.......

 Whoops! this is the WNA thread and _not_ the "state of dental treatment in the UK" sorry but "pain" is the only thing on my mind at the moment and the UK dental service is an absolute DISGRACE!! A dog with a broken leg would get first class care yet these dental butchers charge for the pleasure and don't give a flying screw if you're climbing the walls in agony as a result of their bodge up workmanship...... my crumpet has defrosted, off to get another frozen one..... will be fully active in this thread again once this tooth is finally extracted / ripped / chiselled / torn / beaten / smashed or power vacuumed out of my jaw (probably a combination of all of them knowing my luck 
	

	
	
		
		

		
		
	


	




 )

 Hey Morrissey, do me a favour mate and change your lyrics to be more 2k2 friendly..........

 Pain on the streets of London
 Pain on the streets of Birmingham
 I wonder to myself
 Could life ever be sane again ?

 Hang the dentist, Hang the dentist, Hang the dentist
 Hang the dentist, Hang the dentist, Hang the dentist
 HANG THE DENTIST, HANG THE DENTIST, HANG THE DENTIST
 HANG THE DENTIST, HANG THE DENTIST
 HANG THE DENTIST, HANG THE DENTIST!


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## 12796

You have my sympathies - the worst pain of my life was due to impacted wisdom teeth. They had to be chiselled out of the sides of my jaw bone after first being splintered. I had holes on each side you could put your thumb in after they both got infected!

 My childhood dentist wouldn't give fillings (we later found out he couldn't rather than wouldn't) and made a real pig's ear of my dental treatment as I grew up (in a small town with one dentist). I suffered numerous abcesses and the like that really could have been avoided. He later got sued for multiple malpractice ad drove his car into the river to commit suicide. Fortunately when I was at college I got it all sorted out and I haven't had too many problems since then, bar some expensive replacement crowns when I first went to london. My advice is to see another dentist, get it documented and fixed and then get a good lawyer! I now use a scandavinavian dental practice in london - there come over here out of pity I think. They are cheap too!

 I wouldn't advise crumpet - at least not for that particular swelling . 

 ad843 will arrive tomorrow...


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_You have my sympathies - the worst pain of my life was due to impacted wisdom teeth. They had to be chiselled out of the sides of my jaw bone after first being splintered. I had holes on each side you could put your thumb in after they both got infected!_

 

Luxury! You were lucky to get them removed in one piece mate...... my L/H
 wisdom tooth came out in one piece at the hands of my all time favourite dentist (a London based guy).... the R/H wisdom tooth took almost "1 hour" to budge at the hands of a Scottish dentist and he smashed the adjacent molar to smithereens in the process which meant I had to get it removed also "and" into the bargain all the teeth on the lower left side of my jaw had to be root canalled..... looking back that wasn't anywhere near as painful as this partial tooth with exposed pulp that's "sitting" in my mouth as I type this....... I dream of a "chisel" into my jaw at the moment, anything for a bit of relief . 

  Quote:


  Originally Posted by *biovizier* 
_childhood dentist wouldn't give fillings (we later found out he couldn't rather than wouldn't)_

 

A typical UK dentist then? 

  Quote:


  Originally Posted by *biovizier* 
_I suffered numerous abcesses and the like that really could have been avoided. He later got sued for multiple malpractice and drove his car into the river to commit suicide._

 

Did his patients stand on the river bank throwing ballast into the river to make sure he didn't surface? Sorry.... that was in bad taste.


  Quote:


  Originally Posted by *biovizier* 
_My advice is to see another dentist, get it documented and fixed and then get a good lawyer! I now use a scandavinavian dental practice in london - there come over here out of pity I think. They are cheap too!_

 

He's the "only" dentist for miles around.......... _seeing_ another dentist these days is almost impossible......... (and I'm talking private) It's a screw** disgrace........ what has the UK come down to?

  Quote:


  Originally Posted by *biovizier* 
_ I wouldn't advise crumpet - at least not for that particular swelling ._


----------



## 12796

Nah they didnt come out in one piece. It had to be shattered while still in the jaw and then dug out. It was buried under the back molar so deep under I didn't have a clue it was there. My face was the size of a pumpkin for a fortnight and I couldn't turn my head at all. It killed the molar roots as well - root canel surgery on both sides. Plus it took about 2 years for the holes to fill in. I had to empty out the "pouch" of pus and food after every meal like squeezing a tube of toothpaste. 

 Plus, I had to eat gravel straight after the operation and washed it down with broken glass - that's the meaning of pain! (cue monty python theme song)


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Nah they didnt come out in one piece. It had to be shattered while still in the jaw and then dug out. It was buried under the back molar so deep under I didn't have a clue it was there. My face was the size of a pumpkin for a fortnight and I couldn't turn my head at all. It killed the molar roots as well - root canel surgery on both sides. Plus it took about 2 years for the holes to fill in. I had to empty out the "pouch" of pus and food after every meal like squeezing a tube of toothpaste. 

 Plus, I had to eat gravel straight after the operation and washed it down with broken glass - that's the meaning of pain! (cue monty python theme song) 
	

	
	
		
		

		
		
	


	


_

 

You lucky bugger! I always wanted to go private and experience good treatment like that 
	

	
	
		
		

		
		
	


	




 .

 Mike.


----------



## raja

Hi Mike,

 Is there any chance you can do a quick comaprison for me?

 Can you please compare the ad825 with the ad843?

 The reason I ask is that I have been using the ad825 in the Jung regulators, and have found them to outperform the lm6171. I haven't got any ad843 at hand so I can't compare.
 BTW ALW supplies jung reg boards for £5 each, they really are great, you won't belive the difference they make.

 I have also tried peranders jsr-03, a little more expensive at around £8 a board, but they are even better.......


 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi Mike,

 Is there any chance you can do a quick comaprison for me?

 Can you please compare the ad825 with the ad843?

 The reason I ask is that I have been using the ad825 in the Jung regulators, and have found them to outperform the lm6171. I haven't got any ad843 at hand so I can't compare.
 BTW ALW supplies jung reg boards for £5 each, they really are great, you won't belive the difference they make.

 I have also tried peranders jsr-03, a little more expensive at around £8 a board, but they are even better.......


 Thanks
 Raja_

 

Hi Raja,

 Sorry mate but I don't have any AD-825's to hand so can't do a comparison between it and the AD843. IIRC when I tried the AD-825 in the MKl I wasn't over keen on it and ended up using the two I had in the rail splitters to get rid of them. You'd quite possibly like the AD-843 Raja, well worth a roll in if you can source them.

 All the best.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_ I'd like to try the AD 843s._

 

Hi Alick,

 I should have a couple of extra pairs of AD-843s by the end of this month and I'll be happy to send you a pair to try if you like?

 I'm definitely _very_ impressed with them but I've been on and off and on again with quite a few things audio these past few months and It would be good to get a second pair of trusted ears to evaluate them in the MKll as I'm beginning to think my ears / head are getting in the way of the music.

 I was at the dentist this morning to get the remainder of my tooth extracted and he suggested that my sinuses _may_ be playing a big part in not only my tooth problems but also my taste, sense of smell and hearing....... along with the agonising (seemingly continual) toothache there's a pretty rank taste at the back of my mouth and when I blow my nose it smells like cow dung emitting out of my nostrils. I've never "knowingly" suffered from sinus problems but, the more I think of it, it's all starting to make sense.

 Fortunately I had a Doctors appointment this evening and he had a prod around and reckons there is pressure on my sinus and sent me away with a nasal spray, some amoxycillin antiobiotics and he will be referring me to an ENT specialist.

 All this "head" crap has only come on this past year but if It's all being caused by the sinuses _and_ can be cleared up I'll be very happy indeed......... it sure would explain a lot and kinda makes sense if the Maxillary Sinus is infected..... that would affect the whole head and would / could cause problems like gum infection, hearing problems, loss of taste, headaches etc.

 Hopefully I _don't_ have an infection in my sinus (the bad taste, rotten smell in my nostrils, throat problems, tooth problems, headaches, loss of taste and general feeling of lethargy would suggest I may have) but until I can get it confirmed one way or the other then It's not a good idea for me to be evaluating opamps / commenting on them.

 This Beclomethasone Dipropionate Aqueous Nasal spray seems to be shifting some of the blockage but I can't say "oh yeh the AD843 really blossoms once you snort some Beclomethasone Dipropionate up your nose..... the highs are higher..... the leading edge of the......." blah blah 

 And I don't want to attempt to pretend. I'm not hearing too good due to this bunged up head and am more than happy to send you over the 843 Alick in order that you can evaluate it in my abscence.

 All the best.

 Mike.


 PS: Even with bunged up head the AD-843 came across as something special.


----------



## Alick

Mike

 I'd be grateful for the loan of the spare pair of AD 843's when you get them, thanks. As always, I'll be honest.

 In some ways, it might be good news if you have a sinus infection as it should be relatively simple to sort out and it might well be the cause of many of your recent symptoms. It would be fine if they all disappear after a short course of antibiotics (although, knowing your luck you'll probably turn out to be allergic to amoxycillin 
	

	
	
		
		

		
		
	


	




. Start popping antihistamines if you come out in a red blotchy rash). And keep taking the Beclo, it should certainly help. Fingers crossed ...

 Late thought; if you think that the AD843's sound good now, imagine how they might sound with your hearing optimised (if that is the isuue). Potential audio Nirvana looming?


----------



## BrokenEnglish

Quote:


  Originally Posted by *spendorspain* 
_Drawbacks? Only a very minor and I hope not worrying: when I rotate the volume control fully counterclockwise (I always do that before turning the amp off or when changing interconnects) there is a faint crackling, but only at the very end, never in the useful range of pot. I now simply stop their rotation a little before it ends (anyway, at this point the sound level can be -60/70 dB, I guess)._

 

hi jose, 
 nice to read from another "uncapped" wna! i described the same symptoms of crackling while turning the volco after removing the input caps. it's neither related to plastic or metal knobs, nor to incomplete grounding of the pot. most likely it's caused by dc-offset returned to the input, as dr. white told me some time ago. i was hoping to get rid of it with the 10m-resistor and 100k-trimpot mod, but couldn't test it so far. stay tuned.. i'll try it soon.

  Quote:


  Originally Posted by *PinkFloyd* 
_to cut it short you can use the LM6171 with 10M resistor and trimpot only if you leave the input caps in place...._

 

mike... do you think, one could use the 10m/100k "caps-free" mod in combination with output caps while leaving the input caps out? ah... i'll try it anyway... 
	

	
	
		
		

		
			





 btw... i finished my dual-voltage psu (basically 2 tweaked TREADs with electronic ripple and noise rejection, currently 2*14v DC) to bypass the wna-railsplitter. after 2hs of usage there were no audible advances. but... BUT... now i'm able to increase the rail capacitance without the risk of further transistor death. i started with 1000µf electrolytic, bypassed with 10µf tantalum, bypassed with 0.082 + 0.022µf fkps. very intense bass, nice highs. i'll give it a week of burn in before i report back.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_mike... do you think, one could use the 10m/100k "caps-free" mod in combination with output caps while leaving the input caps out? ah... i'll try it anyway... 
	

	
	
		
		

		
		
	


	


_

 

I really don't know Udo, that question will have to be posed to Dr. White... funny things were going on when I ommitted the input _and_ output caps and fitted the 10M and trimpot.. as I turned the volco the offset changed pretty dramatically....

 Without output cap / input cap _AND_ without the 10M and trimpot (just LM6171 fitted in IC1) both LM6171's measured VERY low offset (+1mV and +4mV) so I thought "hello there, two well matched LM6171's this is good"

 BUT........ when I turned the volco clockwize the offset went CRAZY... the more I turned the volco the crazier it got ( something like +150mV and -300mV) I'm glad I didn't have my headphones plugged in and I'm glad I didn't rely on the reading with the volco at minimum position.

 I explained this to David and he says It was due to the input caps not being in place...... it sure seemed pretty weird to me and I trust David will explain why this was happening shortly... I'll post as soon as / if I hear anything. 

  Quote:


  Originally Posted by *BrokenEnglish* 
_btw... i finished my dual-voltage psu (basically 2 tweaked TREADs with electronic ripple and noise rejection, currently 2*14v DC) to bypass the wna-railsplitter. after 2hs of usage there were no audible advances. but... BUT... now i'm able to increase the rail capacitance without the risk of further transistor death. i started with 1000µf electrolytic, bypassed with 10µf tantalum, bypassed with 0.082 + 0.022µf fkps. very intense bass, nice highs. i'll give it a week of burn in before i report back._

 

Ah Nice one Udo 
	

	
	
		
		

		
		
	


	




 Now you don't have to worry about taking out the transistors and CRD's in the rail splitter 
	

	
	
		
		

		
		
	


	




 That was so funny mate, both you and I fitting crazy caps in the rail splitter and wiping out the transistors and CRD's.... my amp continued to work though and actually sounded great with the burnt out transistors..... it was only when I glanced at them one day I noticed the scorch marks on them and alarm bells started ringing 
	

	
	
		
		

		
		
	


	




 The large inrush current (using the large caps) had obviously blown the arse out of the trannies and CRD's..... what amazed me though was the fact the amp still worked _and_ sounded absolutely FAB with half the railsplitter toasted 
	

	
	
		
		

		
		
	


	




 Do you have any pics of your new PSU Udo? I'd really love to see it mate. I'm happy It's working well and even happier that your WNA sounds better with it...... now you've got the PSU sorted out you can maybe try a MKll board with it as provision is made on either PCB1 or PCB2 to bypass the rail splitter..... in fact, there are a lot of PSU options on the MKll boards if you're into playing about with PSU configurations 
	

	
	
		
		

		
		
	


	









 I think the amp could be improved by incorporating a TLE2426 into the railsplitter circuit and, for the kit builder on a budget, it would mean they would get even better performance from a cheap wallwart PSU and it would save on a few resistors.........

 First and foremost I'm searching for bang for the buck (not for me but for others new to the scene) and am a great believer in evolution rather than revolution...... My part in this is simple...... I want people to get the max at the minimum cost which is why I tend to stick to the recipe and report on a cheap ingredient that may make it taste better......... I seldom add saffron and oysters to my recipes.......

 I'm starting to go off on a tangent but, in a nutshell, the WNA kit "as is" is a superb amp but adding saffron / oysters and other exotic ingredients is an option that adventurous chefs have up their sleeve and a recipe which may taste wonderful but the baked beans and toast approach I adopt is aimed at the beginner.

 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Without output cap / input cap AND without the 10M and trimpot (just LM6171 fitted in IC1) both LM6171's measured VERY low offset (+1mV and +4mV) so I thought "hello there, two well matched LM6171's this is good"
 BUT........ when I turned the volco clockwize the offset went CRAZY... the more I turned the volco the crazier it got ( something like +150mV and -300mV) I'm glad I didn't have my headphones plugged in and I'm glad I didn't rely on the reading with the volco at minimum position.
 I explained this to David and he says It was due to the input caps not being in place...... it sure seemed pretty weird to me and I trust David will explain why this was happening shortly... I'll post as soon as / if I hear anything._

 

yeah, mike... that's the sort of behaviour one would expect from our experiences without input caps (leaving the output caps in). i'll try the 10m/100k thingy as next step. but one thing is sure: as long as i own this amp, it will be free of input caps. i'll also try the effects of decreasing the input impedance to 10k. let's wait and hear... 
	

	
	
		
		

		
		
	


	




 (oops... i think, you don't like this smilie at the moment... so... for you mike: 
	

	
	
		
		

		
		
	


	




 ...sorry... couldn't resist... 
	

	
	
		
		

		
		
	


	




 )


  Quote:


 That was so funny mate, both you and I fitting crazy caps in the rail splitter and wiping out the transistors and CRD's.... 
 

yeah.. i'm still traumaticed... i don't like pluggin in the dt440 any more, the phones i used when i "grilled" the transistors the first time... 
	

	
	
		
		

		
		
	


	




  Quote:


 Do you have any pics of your new PSU Udo? I'd really love to see it mate. 
 

here it is: http://www5.head-fi.org/forums/showp...&postcount=564

  Quote:


 I'm happy It's working well and even happier that your WNA sounds better with it...... 
 

well... i'm not quite sure, if it sounds really better. i don't have my reference phones (dt880) with me and also have to wait for further progressions of burn in. but... you know... it's so much fun to have the option of playing with rail capacitance...

  Quote:


 now you've got the PSU sorted out you can maybe try a MKll board with it as provision is made on either PCB1 or PCB2 to bypass the rail splitter..... in fact, there are a lot of PSU options on the MKll boards if you're into playing about with PSU configurations 
	

	
	
		
		

		
		
	


	



 

hehe... you devil... 
	

	
	
		
		

		
		
	


	




 ...i'll join the club... as soon as i've done all the modding with the mkI that will guide me to my dream mkII.... 

  Quote:


 I think the amp could be improved by incorporating a TLE2426 into the railsplitter circuit and, for the kit builder on a budget, it would mean they would get even better performance from a cheap wallwart PSU and it would save on a few resistors......... 
 

well... i don't think so... the tle2426 most likely will not provide enough current for the wna. eventually dr. white could think about replacing the railsplitter ic with a buffer (buf634?) to give us a little bit more juice. but maybe this is just a silly idea... 

 wish you a nice and painless evening, mike...
 udo


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_


 here it is:_

 

It's here too looks GREAT Udo!!: 
















 Beautiful job Udo, truly FAB 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## 12796

Any update on the ad843 Pinkie? Still waiting for mine to arrive...


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Any update on the ad843 Pinkie? Still waiting for mine to arrive..._

 

Hi Nick,

 I'm still listening to it and my head is a lot clearer than it was a couple of weeks ago..... I still like the AD-843 a lot. This is one of these instances where it would be ideal to have two WNA's running side by side through a comparator, one with the LM6171 on board and the other with the AD-843 on board.... by the time you remove the AD-843 and replace them with LM6171 and output caps etc. It's hard to remember what the other opamp sounded like.

 Switching between two amps through a comparator would give me a much better, and more immediate, insight into the qualities of both opamps so I may well build another WNA solely for opamp evaluation.... I know this is bordering on being clinically obsessed with opamps but, what the hell, it keeps me off the streets and out of mischief 
	

	
	
		
		

		
		
	


	




 I had a peek at the AD843 datasheet earlier and snipped this little morsel out of it:






 I'll have a go at the bypassing over the weekend and if I do build up a second WNA amp to compare opamps I'll ditch the dip8 sockets and solder the AD843 directly to the board as suggested in the datasheet.

 One thing I can say Nick, the AD-843 and LM6171 are the only two opamps that can reproduce my reference recordings accurately.... the OPA627, AD-811, OPA134 etc. make mincemeat of the recordings and totally bastardise the pace, rhythm and timing.... they add insult to injury by seemingly placing a 500 denier veil between the headphones and my ears.... the 627 is pretty rank sounding compared to the LM6171 / AD-843.... so much so that a comparator is not necessary to differentiate between 627 and LM6171 / 843... OPA627 just sounds plain wrong in the WNA application. The LM6171 / AD-843 are a different kettle of fish and "seem" pretty close to the mark when listening to my reference tracks and you really would need to have either a prolonged listen to both or a brief switchable comparo between the two before you could make your mind up....... LM6171 V OPA627 is night and day, AD-843 V OPA627 is night and day, AD-843 V LM6171 is pistols at dawn.... hard one to call.

 Having said that, as always, It's all dependant on the synergy of your system _and_ your own ears.... I can only comment on what I hear and I'll only listen to something that I like and _never_ rely on other peoples reviews as we all have ears which are as unique as our fingerprints (no two ears are the same) and only _your_ ears can be the judge at the end of the day..... that's why audio equipment and opinions are so diverse, if we all had the same pair of ears and we all heard things the same way then it would be easy but we don't which is why It's so hard to find the sound that suits your ears...... that's why I DIY, I've got a certain amount of control and can tailor the device to suit my ears.... whether what sounds good to me will sound good to you is another matter..........

 All the best.

 Mike.


----------



## 12796

thanks! I assume if you have two amps you can also additionally leave one fully optimised for the lm6171 while you experiment with tweaking for the ad843... at the moment it is working in the environment developed for the lm6171. Teeth ok now?


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_thanks! I assume if you have two amps you can also additionally leave one fully optimised for the lm6171 while you experiment with tweaking for the ad843... at the moment it is working in the environment developed for the lm6171. Teeth ok now?_

 

Well no....... amp one will be tailored around the AD-843.... let's call it AD1..... amp 2 will be purely an LM6171 tailored amp...... if I am to try out composite opamps etc. then I'll need to build "amp 3" I'll be ordering the TANTALUM caps and ceramic caps for the AD-843 bypass tomorrow as Rapid have a promotion on at the moment "free delivery if you order online at the weekend during the month of May"...... so, first and foremost I want to try bypassing the 843 with the TANTs and ceramic caps...... if they bring about even 10% improvement I'll be happy and may not even bother building up a comparo WNA........ let's see what happens.

 My teeth are great (gums I should say) "touchwood" I ended up going back to my own dentist (pain driven decision) and he whipped it out pretty sharpish and cleanly......... he obviously didn't want bad press / vibes and made sure that I was treated "properly" He was well aware of my phone calls to the dental Hospital and dental council etc.... remainder of tooth was whipped out after 30 minutes or so of gouging and stirring a chisel around in my mouth so a good day was had by all! I dropped 40mG of valium 20 minutes prior to the extraction so I probably wouldn't have flinched if his chisel had slipped and penetrated my esophagus! 

  Quote:


  Originally Posted by *biovizier* 
_thanks! I assume if you have two amps you can also additionally leave one fully optimised for the lm6171 while you experiment with tweaking for the ad843... at the moment it is working in the environment developed for the lm6171. Teeth ok now?_

 

Well no....... amp one will be tailored around the AD-843.... let's call it AD1..... amp 2 will be purely an LM6171 tailored amp...... if I am to try out composite opamps etc. then I'll need to build "amp 3" I'll be ordering the TANTALUM caps and ceramic caps for the AD-843 bypass tomorrow as Rapid have a promotion on at the moment "free delivery if you order online at the weekend during the month of May"...... so, first and foremost I want to try bypassing the 843 with the TANTs and ceramic caps...... if they bring about even 10% improvement I'll be happy and may not even bother building up a comparo WNA........ let's see what happens.

 My teeth are great (gums I should say) "touchwood" I ended up going back to my own dentist (pain driven decision) and he whipped it out pretty sharpish and cleanly......... he obviously didn't want bad press / vibes and made sure that I was treated "properly" He was well aware of my phone calls to the dental Hospital and dental council etc.... remainder of tooth was whipped out after 30 minutes or so of gouging and stirring a chisel around in my mouth so a good day was had by all! I dropped 40mG of valium 20 minutes prior to the extraction so I probably wouldn't have flinched if his chisel had slipped and penetrated my esophagus..... I was medically prepared for the worst case scenario.

 The best part of it..... "no charge" (I should bloody well hope not given the circumstances!!!) and the socket "touchwood" is starting to heal up nicely..... a good healthy looking clot has formed and I'm rinsing with warm salt water between beer, fags and eating so I hope It'll heal up ok.

 Best part is I'm "Pain Free" after almost 4 months of continual discomfort and about 11 days of "excrutiating agony"..... I can't even begin to tell you how good it is to be able to sleep, eat, concentrate and "live" again.......... Well, I still can't _eat_ in the conventional sense but I can sleep, concentrate and I feel a lot more part of the universe than I did this time last week.

 It's a shame I had to be at the business end of the poor UK dental health care problem after 44 years of superb (and extensive) dental treatment but It's been an eye opener (an a jaw opener) for me and if that's the way you get treated privately my heart goes out to all the people that can't register under the NHS and are forced into to pulling their own teeth.

 We need Dentists in the UK and we need adequate funding from the Government to make "NHS" treatment an option the "dentist" will profit from.............. The NHS character who had a go at pulling my tooth (in the abscence of my dentist) charged £16 for "3" X-Rays _and_ the extraction.............. private treatment is £9 per X-Ray and £35 for an extraction so that's £62 for the same thing........ quite a difference........... If you are unemployed in the UK the NHS treatment is FREE.

 Bad state of affairs but thank God I'm pain free at last Nick 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## 1UP

I have an OPA627 in a Headsave Classic headamp and it sounds quite lovely there, so I guess it's all down to synergy per system, as you say.

 FYI - I have a MOS100 power amp on order from David which uses the OPA627 in its pcb - I guess it's a completely different application, though, as he said the LM6171 is much too fast for this purpose. 

 Then again, the LM6171 is used in the buffer amp, which I guess is not so dissimilar from the headamp. I just think the LM6171 sounds great, myself.

 Ah, the burden of choice / analysis-paralysis!


----------



## PinkFloyd

Quote:


  Originally Posted by *1UP* 
_I have an OPA627 in a Headsave Classic headamp and it sounds quite lovely there, so I guess it's all down to synergy per system, as you say.

 FYI - I have a MOS100 power amp on order from David which uses the OPA627 in its pcb - I guess it's a completely different application, though, as he said the LM6171 is much too fast for this purpose. 

 Then again, the LM6171 is used in the buffer amp, which I guess is not so dissimilar from the headamp. I just think the LM6171 sounds great, myself.

 Ah, the burden of choice / analysis-paralysis!_

 

Horses for courses.


 Pinkie.


----------



## PinkFloyd

It's like winter here today so I spent and enjoyable hour in front of a heater, armed with a soldering iron, fitting the 10M resistor, trimpot and input caps to have another go at the LM6171 without output caps.

 Success!





 Trimpots secured to the chassis using sticky backed velcro strips

 I adjusted both channels to 0.00mV and left the amp on for one hour. The left channel had floated to 0.09mV and the right channel to 0.08mV. I readjusted both channels back to 0.00mV and they have remained at 0.00mV ever since 
	

	
	
		
		

		
		
	


	




 Had a brief listen and holy torpedo batman it didn't half sound good! After reading Jose's findings when he removed the 330K resistor I went back outside with the amp and desoldered them and back in for another listen. 

 Yup, the life certainly has returned to the HD-600 now and there definitely is more space between the instruments, extra clarity and dare I say it.... better defined bass. This could be a result of no output caps _and_ removing the 330K resistor but I think removing the output caps has probably contributed the most... those Nitai caps definitely had their own "signature" (as did the ALCAPS) but without output caps the sound is a lot cleaner as it doesn't have to pass through electrolytics before it reaches your ears... makes sense.

 I'm leaving this amp with LM6171 in situ (without output caps) as the sound is pretty much bang on and I don't want to spoil it by messing about with other opamps so the lid's going down on it now. I'll build another one in the next couple of months which will be based around the AD-843 or even a composite AD843 / LM6171 in tandem (that would be really cool 
	

	
	
		
		

		
		
	


	




) but, for the time being, I don't want to over egg the pudding and spoil the sound of this amp so will keep my soldering iron away from it 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.

 EDIT: a good way of describing the sound without output caps is "extra sparkle" 





 At last! No output caps and 0.00mV DC offset


----------



## BrokenEnglish

that's quite encouraging, mike! thanks!
 what happens dc-wise if you switch off the amp and turn it on again after ~1h of cooling down?

 ah... and you didn't try your 10m/100k without output- _and_ input-caps accidentally? 
	

	
	
		
		

		
		
	


	




 sunny greatings to you.... it's the hottest day over here (~30°C)...
 udo


----------



## PinkFloyd

On the subject of the TLE2462 being used in the rail splitter I asked Dr. White and here's his take on it:


 [size=medium]This is very easy to arrange, you simply remove the two 10k resistors in the rail splitter (and possibly the associated 100nF cap too) and replace them with the TLE2426. The TLE2426 In terminal goes to the rail splitter positive line ( +V ), the Common terminal to the rail splitter negative line ( -V ), and the Out terminal goes to what was the junction of the two 10k resistors. The LM6171/BD139/BD140 then acts as a high current buffer to the TLE2426[/size]

 And just when I thought it was safe to bolt the lid down


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_that's quite encouraging, mike! thanks!
 what happens dc-wise if you switch off the amp and turn it on again after ~1h of cooling down?

 ah... and you didn't try your 10m/100k without output- and input-caps accidentally? 
	

	
	
		
		

		
		
	


	




 sunny greatings to you.... it's the hottest day over here (~30°C)...
 udo_

 

Hi Udo,

 It will not work without input caps.... they _must_ be in position. From cold the offset measures 0.09mV L - 0.8mV R after about 20 minutes or so both channels measure 0.00mV so there's not even "one" millivolt to worry about between hot and cold which is excellent!!

 Mike.

 EDIT: It's 12C (50F) here today and blowing a gale.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_It will not work without input caps.... they must be in position. From cold the offset measures 0.09mV L - 0.8mV R after about 20 minutes or so both channels measure 0.00mV so there's not even "one" millivolt to worry about between hot and cold which is excellent!!_

 

fine! thanks!
 have you also removed r11, mike?


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_fine! thanks!
 have you also removed r11, mike?_

 

The incandescent lamp has been removed yup.... I replaced it with a ferrite bead inductor.

 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_The incandescent lamp has been removed yup.... I replaced it with a ferrite bead inductor._

 

ah.. *cough*... sorry.. wasn't aware that...


----------



## PinkFloyd

Meant to say..... solder the wiper of the trimpot (with 10M in series) to pin 3 of the LM6171.... then solder one side of the track to ground and the other side to pin 4 of the LM6171. The wiper is usually the centre leg on the trimpot.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_ah.. *cough*... sorry.. wasn't aware that... 
	

	
	
		
		

		
		
	


	


_

 

A zero ohm link will do but I had a couple of spare ferrite bead inductors so used them instead.

 Mike.


----------



## PinkFloyd

As I say... you can connect to pin 4 of the LM6171 which is -12V (or near to the pin on the same track)

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_ah.. *cough*... sorry.. wasn't aware that... 
	

	
	
		
		

		
		
	


	


_

 

Yep, the bass will go down a couple of octaves deeper when you replace the 22R incandescent output lamp with a zero ohm link.

 Mike.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_On the subject of the TLE2462 being used in the rail splitter I asked Dr. White and here's his take on it:

 This is very easy to arrange, you simply remove the two 10k resistors in the rail splitter (and possibly the associated 100nF cap too) and replace them with the TLE2426. The TLE2426 In terminal goes to the rail splitter positive line ( +V ), the Common terminal to the rail splitter negative line ( -V ), and the Out terminal goes to what was the junction of the two 10k resistors. The LM6171/BD139/BD140 then acts as a high current buffer to the TLE2426_

 

what do you think are the advantages of switching an additional tle2426-railsplitter in front of the railsplitter-part of the mkII, mike?


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_what do you think are the advantages of switching an additional tle2426-railsplitter in front of the railsplitter-part of the mkII, mike?_

 

I doubt it will sound any better but it will measure better on paper I'd imagine... the TLE will conform to better tolerances than the 2 10K resistors... hell It's worth a go, particularly considering I've got a few of them sitting about doing nothing. Plus it will save on board space should a MKlll ever be on the cards and negate the need for resistors, capacitor etc. 

 Dr. White is going to try one over the weekend to see how it measures up so I won't fit one until I get the all clear from WNA along with the measurements.

 Mike.


----------



## spendorspain

Hi

 Mike, I'm glad to hear your dental health is good again… some of your recent posts seemed horror tales. I wish you new fun moments playing with op-amps, caps, resistors, trimmers and a soldering iron and enjoying music… 
	

	
	
		
		

		
		
	


	




 Regarding the debate on the capacitors in WNA amp, I’d like to post my opinion. I must admit that my electronic knowledge is very basic, and this post is based mostly in ideas picked from this and other forums, my listening impressions and (I think) a little common sense.

 The sound of the LM6171 op-amp is truly special and I’d like to keep it. The WNA hp amp is optimised around it and there is an unanimity about its fast and transparent sound, if properly implemented, that I’ve not found about other op-amps (not even the OP627 or AD843). However, according to several posts in this forum, it has a weird behaviour in dc offset (Mike has even measured it). With other op-amps there is no need to prevent it perhaps because they seem inherently “dc offset-proof” (which the LM6171 _is not_). Therefore, it is possible that the LM6171 generates _itself_ a dc offset at its output, that amplified by the following stages in the amplifier can be dangerous to the headphones connected to the amp, even damaging them. 
 The resistor-and-trimpot solution is good but it is complicated to implement (it needs careful and individual measuring and adjustment) and perhaps changes in temperature or any abnormal situation can drift the dc value for what it is adjusted, making it nearly useless. 
 An _output_ capacitor in series is the bullet-proof solution and a good sounding one, assuming the cap is high quality (to avoid a loss of transparency or a mushy sound) and high value (to avoid phase shifts and an impaired bass response). I hope the Black Gate bipolar Nx 1000uF/25V I use is up to this task. In any case, a small loss of quality (if it does exist) would be compensated by the peace of mind of knowing that under _no_ circumstances my beloved (and expensive) Grado HP-2 headphones can be destroyed by dc amplified by the WNA amp, simply because this would have been blocked by the output caps before reaching the outside world.

 However, I’m going to keep the _input_ caps out. Without them, the amp sounds better than ever and I assume it is safe not to use them, as the majority of sources have no problems of excessive dc offset and many have their own output caps, making the input caps in the WNA redundant (I’ve measured various CD and DVD players, with readings from 0 to 1-3 mV). And, even if _all_ goes wrong and, for whatever reason, a burst of dc coming from the source goes into the "input cap-less" WNA amp and damages any of their components, their repair would be a lot easier and cheaper than doing so with a pair of expensive headphones or (if I use the WNA as a preamp in a future) a power amplifier and a pair of loudspeakers, because these all were protected by the output caps in the WNA amp. Remember that the modest cost of Dr. White’s little amp is far below its great musical performance.

 BTW, I have a question to Udo and Mike, regarding the crackling noise when I turn the volume all the way down. Using an insulating glove or touching one of the rear screws of the pot with a wire connected to ground has no effect. Is it dangerous to my headphones or whatever is connected to the output of WNA amp or simply is it a small nuisance?. I assume that with output caps it is _impossible_ for dc offset to find its way outside the WNA amp. I’ve read in the HeadRoom webpage that in their AirHead hp amp (which I have, as my portable, battery-powered amp) they use output caps, but not caps around the volume control, in order to get the best sound quality, although the price to pay is a small noise when turning up or down the volume, similar to that I have in my “input cap-less” WNA amp. If this crackling is not dangerous, perhaps I don’t even bother to fix it 
	

	
	
		
		

		
		
	


	




 .

 Regards
 Jose

 PS.: Udo, the PSU you have built is impressive and I’m looking forward to hear your listening impressions, as I’m sure that the power supply is a very important factor if one searches truly the ultimate sound quality. I have a WNA cascode PSU connected to my WNA hp amp with great sonic results, but I’m a little confused about the different wiring options and I need a bit of help and advice… but I’ll left that for another post…


----------



## BrokenEnglish

hi jose,

 first of all, i perfectly understand everyone who enjoys the acoustical benefits of leaving those input-caps out. unfortunately in this case there seems to be no way to prevent the lm6171 from straying some - then increasing - dc-offset back to the inputs while you turn the volco - and that causes the crackling we are hearing. in fact you could read some minor spikes of mV DC with your DMM while you readjust the volume: given the input-capless mkI i read values between 2-10mV for a few tenth of seconds - nothing to worry about, but obviously audible as crackling noise. your black gates maybe do a better job in filtering the offset out at all. just test it.

 of course i also understand your feeling of protection behind your output caps. personally i thought about implementing amb's epsilon 12 circuit for the same reason, because it can detect dc-offset and mute the outputs. but i'm not sure, if i'm skilled enough right now, to build it... 
	

	
	
		
		

		
		
	


	




 hm.. and my psu... well... let's say, it is a built in progress. i'd bet you could yield better results with dr. white's cascode psu, configured as dual-voltage psu (should be no problem at all - all you'd need are some jumpers, different cables and some some sort of three-pole-connectors psu->wna ha). to keep it short: i heard nearly no audible advantages after switching from my single-voltage-supply with the wna-railsplitter behind to my my simple dual-lm317 psu. the only thing that matters there, is that i'm now able to play with higher rail-capacitance. it's quite time-consuming to test different values of faster (tantalum, foils, ceramic) and slower (electrolytic) caps inside my amp but it is also very interesting: it's like fine-tuning or "voicing" the amp. if you'd like to join that game, you'd have to take the dual-voltage route, because the wna-railsplitter - as mike and i had to realize - is not able to handle capacitances higher than 220µf. 
 but to be honest, for now i'm not too happy with my results. i have more bass, but i'm missing some presence and resolution in the upper parts of the audio spectrum. maybe that's due to progreding burn-in effects in lots of caps. and there are other parts on my optimisation-list: today for example i tested the effects of cables with higher diameter (connection transformer->regulator) and found, that most likely i didn't use the right (i.e. to small) panel-wires in my psu. that means, i have to rewire the whole panel-stuff... 
	

	
	
		
		

		
		
	


	






 well... it never ends... 
	

	
	
		
		

		
		
	


	




 cheers,
 udo

 /edit: one additional important note on single- vs. dual-voltage psu's for the wna ha. there's one BIG, potentially dangerous disadvantage of dual-voltage psus: i expect a real BLAST of dc-offset in case one of the rails of my psu collapses (due to simple cable break for example). those things should never happen with the railsplitter, that adjusts the ground in symmetry between the + and - rails.


----------



## PinkFloyd

Hi Jose,

 I'm afraid input caps are essential with the LM6171. you can safely dispense with the output caps and fit the 10M and trimpot and the DC will not drift at all..... I set mine to 0.00mV on both channels about 26 hours ago and the reading is still 0.00mV on each channel.

 If you think your amp sounds good without input caps you'll be amazed at how fantastic it sounds _with_ input caps but _without_ output caps... It really is the electrolytic output caps that are getting in the way of truly glorious sound..... since removing them and fitting the 10M and trimpot It's like listening to an entirely different amp.. just pure crystal clear sparkling sound..... superb.

 Honestly, once you fit the trimpot / 10M and adjust to 0.00mV per channel it doesn't drift at all. Just make sure you solder the 10M resistor onto the wiper of the trimpot very well _and_ shrinkwrap it to ensure a good, robust, mechanical connection. 

 If you're not happy with this you _could_ go down the long route which would involve soldering two leads onto pin 3 and 4 of the LM6171 and terminate these leads with crocodile clips....... next arm yourself with a couple of hundred +/- 5% carbon film resistors and work your way through the resistors until you find one that matches as close to 0.00mV as possible (anything under 10mV is ok) when you find one that is pretty close to 0.00mV then you just solder it between pins 3&4 of the LM6171 and you're good to go.

 The trimpot is a better way of doing it (and faster) but there should be no reason any massive DC will reach your headphones unless something like the resistor drops off (very unlikely) even if the full DC of a naked LM6171 got through It's unlikely it would blow your headphones... so, as I say, don't be frightened to remove the caps and replace with 10M and trimpot... many amps use trimpots to adjust the offset and resistors are pretty unlikely to fail in this application (touchwood!)

 All the best.

 Mike.


----------



## PinkFloyd

I haven't tried the TLE 2462 yet but drew a couple of diagrams up in photoimpact and sent them to Dr. White just to be sure I was connecting the TLE 2462 to the right places........ I'm no graphics expert so please excuse the strange diagrams...... one shows the Underside PCB connection and the other shows the top connection...... in both instances R12 and R13 are removed (10K resistors)





 Underboard connections





 Top of the board pad connections



 Dr. White tried the TLE 2462 today and says:

* "Mike,
 Both of your diagrams are correct. I tried it this morning and it works fine. I'm not sure if there's any benefit though. Using two 0.1% resistors to define the midpoint of the supply will give better accuracy than a TLE2426 which is good for around 1%. One of the 10K resistors is bypassed by a 100nF capacitor which will give you some noise reduction - the TO92 version of the TLE2426 doesn't have a noise reduction pin so you lose out there too. Incidentally the 100nF capacitor should either be left out or increased to more than 1uF for guaranteed stability ( see ti datasheet ). The one advantage that the TLE2426 has is that its cheaper than two 0.1% resistors. I didn't do any critical listening so I don't know whether the TLE2426 has any effect on the sonics.

 Regards, David."  *


 Armed with that info I will not be removing the 10K resistors from R12 & R13 and fitting a TLE 2462...... however, if I were building another WNA then I would fit the TLE 2462 in place of the 0.1% resistors as it would be more cost effective and basically do the same thing....... to hell with it, I'll fit a TLE 2462 in situ tomorrow and do some "critical" listening 
	

	
	
		
		

		
		
	


	




 In for a penny in for a pound..... It's an easy affordable tweak so may as well give it a go.

 Mike.


----------



## PinkFloyd

On the subject of DC offset that Jose posed Dr. White responds:

* "Fortunately such events rarely occur in normal use; I've never had a "normal use" dc offset fault with any amp, power or headphone, in goodness knows how many years of designing/buliding/tweaking. BUT, once in a very blue moon such things do happen, and the WNA will happily toast any attached headphones. It can deliver an amp or two for a short period of time - long enough to fry headphones. In normal use I would estimate that you'd be very unlucky to have such a failure in 30-40 years of hard use. If you want belt and braces protection you can use a headphone protection unit that disconnects the headphones in the event of a dc offset. As I mentioned to you a couple of times previously I'm in the process of upgrading my loudspeaker protection unit to cater for headphones ( this preceded ambs unit ). The pcb design is now complete and kits should be available in 3-4 weeks time. The trip level can be set to whatever you like ( typically 50mV ) and it provides led indication of fault and normal conditions. It uses a chunky 8A relay with big silver stud contacts to do the business. Power required is around 50mA at +12V and 5mA at -12V. The power can be either ac or dc - a little 3VA transformer will do fine. You can put the unit in the same box as the headamp, if you have room, or in a separate box." *

 You've got to keep this guy on his toes 
	

	
	
		
		

		
		
	


	




 Nice one.


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_On the subject of DC offset that Jose posed Dr. White responds:

* [...]Power required is around 50mA at +12V and 5mA at -12V. The power can be either ac or dc - a little 3VA transformer will do fine. You can put the unit in the same box as the headamp, if you have room, or in a separate box.*_*
*
*


so... why not use the amp's psu, in case anybody out there uses a dual-voltage psu? 
	

	
	
		
		

		
		
	


	




 /edit... of course another voltage splitter should also be able to do the job... hm... have to ask dr. white first.*


----------



## PinkFloyd

good question awaiting answer. In the meantime I'm prepared to take the risk re: the 10M/ trimpot scenario......... sounding awesome and unlikely to fail "ever" let alone in "30-40" years.

 Class on a stick!


----------



## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_[...]In the meantime I'm prepared to take the risk re: the 10M/ trimpot scenario......... sounding awesome and unlikely to fail "ever" let alone in "30-40" years._

 

i'll follow you, mate... some new mundorf 4,7µf polyprop caps (they were thought as output caps for the dddac... 
	

	
	
		
		

		
			





 ) should arrive early this week, all the other stuff is in the box...


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_i'll follow you, mate... some new mundorf 4,7µf polyprop caps (they were thought as output caps for the dddac... 
	

	
	
		
		

		
		
	


	




 ) should arrive early this week, all the other stuff is in the box... 
	

	
	
		
		

		
		
	


	


_

 

As long as your connections are mechanically sound you'll be good for life mate. <why are people frightened to remove the output caps???> arm yourself with a 10M resistor and a half decent (bournes) 100K trimpot and you'll never look back.........


 Mike.


----------



## Alick

I _think_ I'm keeping track here. Mike, is your current set-up as follows: LM6171, input cap's but no output cap's. trim pot offset adjustment, original QC settings, 330k removed?


----------



## 12796

Can you get away with removing input AND output caps if you use ad843 with a trim pot? what about the qc and 330?


----------



## BrokenEnglish

Quote:


  Originally Posted by *biovizier* 
_Can you get away with removing input AND output caps if you use ad843 with a trim pot? what about the qc and 330?_

 

there should be no need to adjust zero-offset via trimpot with the ad843, biovizier. mike tested them without in- and output caps.


----------



## 12796

Great - any idea of what the residual offset remaining and the drift were? Hopefully I can take the caps out of my phono too and replace LM6171 with ad843 and trimpots if they are low enough.


----------



## BrokenEnglish

again.. there should be no need for the 100k trimpot or the 10m resistor with ad843 as with every other "usual" opamp. dc-offset should capless stay < 15mV. if you insist, i'll test it in the mkI at the end of the week.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I think I'm keeping track here. Mike, is your current set-up as follows: LM6171, input cap's but no output cap's. trim pot offset adjustment, original QC settings, 330k removed?_

 

Hi Alick,

 Yes, It's as you describe I'll up the QC as soon as I get hold of some heatsinks..... trying it without the 330K for a bit.

 Mike.


----------



## 12796

Thanks! It's ok it wil be fine in the pre and headamp. I will stil need trimmers for the phono though if I take out the caps.


----------



## BrokenEnglish

i don't know, what you're trying to do with your phono-stage, biovizier, but the trimpot-solution dr. white suggested to limit the dc-offset of the lm6171 IMO is not applicable to limit the offset of every other opamp with much smaller bandwidth (like the ad843). but maybe we're simply speaking of different things. good luck to you!


----------



## 12796

Dont worry - I will discuss with Dr white. Tried it with the ad811 in the phono before but the drift was too high to rely on the zeroing.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Great - any idea of what the residual offset remaining and the drift were? Hopefully I can take the caps out of my phono too and replace LM6171 with ad843 and trimpots if they are low enough._

 

Hi Nick,

 No need for trimpots, output caps or input caps with the AD-843. The offset is very low (mine measured 0.08mV and 0.1mV) so you can plug them in naked and they should be fine.

 You're possibly best trying the headamp with the LM6171 for starters and then experimenting with other opamps after you get used to the LM6171 sound. After much beating about the bush with caps in, caps out, trimpot in, trimpot out, 330K in, 330K out etc. I must confess the best combo (to my ears) has to be LM6171 with input cap, no 330K (in your case you may however prefer it with 330K as it smooths the sound out a touch) no output caps and 10M and trimpot in place.

 This opamp rolling can be fun but after a while it gets pretty tedious continuously replacing resistors and caps and I always seem to find myself back where I started with the LM6171 on board which kinda suggests to me that it is the best overall opamp for the WNA...... I know I seem contradictory one day saying LM6171 the next day praising the AD-843 only to go back to the LM6171 a few days later but, as you know, It's not straightforward evaluating "sound"... one day you could be in the mood for music and even the ****tiest of opamp could sound out of this world.... the next day you may not be "tuned in" and the _best_ op amp could sound like mud to your ears.... there are so many variables to contend with but I find the weakest link in the chain to be the human mind... you really have to be in the mood for music to truly get into it and feel it washing over you and those instances are pretty few and far between and It's not possible to condition your mind to enjoy music It's something that happens naturally.

 Sometimes you have a "magical moment" when listening to music where the hairs on the back of your neck stand out and you really are at one and part of the event.... that's got nothing to do with the equipment that's all down to the state of mind you're in when you're listening..... try listening to music standing up with a toothache, it sounds *****..... find yourself in a dimly lit room, totally relaxed with you eyes closed and sometimes the music is so palpable you think you're on stage with your favourite band and can walk about on that stage and around the musicians homing in on each individual element........ when you get a moment like that you expect it to sound like that every time you listen to it but it doesn't work that way.. you have to be in the right surroundings and in the right mood...... It doesn't matter what equipment you have, if you're not conditioned to receive music no amount of opamp rolling or upgrades will make it sound good.

 I've tried placebo mood conditioners like rainbow foil, purple LED's, Interconnects, plasma balls, ambient lighting etc. and I have also tried mind altering drugs such as alcohol etc. but none of these will ever come close to a totally natural musical experience / magic moment..... placebo used to get my creative sub conscience salivating and I'd buy a piece of equipment after firstly reading a what Hi-Fi write up and then listening to it in my local Hi-Fi dealers listening room.... I'd get it home and be amazed by the sound (for about 48 hours) only to be unsatisfied with the sound after a couple of days...... those days are long gone and I learn't quite some time ago that the most important part of the chain (or the weak link) was myself..... Music will not be magical unless you're in the state of mind to totally relax and get into it and you can't condition yourself into that state of mind.

 I've had about 30 magical moments with the WNA, a few of them with the LM6171, a few with the AD-843 and a few with the AD-8605. They were all pretty intense moments but the intensity was always "more" with the LM6171 and I found myself able to explore the tapestry and structure better with the LM6171...... this is when I really am able to sort the wheat out from the chaff....... when I experience an intense magical moment I can not only explore every aspect of the sound but I can also visualize and paint a colourful tapestry to accompany the music... the music quite literally acts as a mind altering drug.

 As I say, these moments are few and far between and for everyday listening the LM6171 / AD8065 / AD843 will do the job but whenever you find yourself at one with the music you really do want to be on the business end of the LM6171..... It really stands out when you're naturally conditioned to receive.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Dont worry - I will discuss with Dr white. Tried it with the ad811 in the phono before but the drift was too high to rely on the zeroing._

 

Conditioning or not the 811 sounds damned horrible 
	

	
	
		
		

		
		
	


	




 As Udo says the 10M and trimpot is only applicable to the LM6171..... you won't be able to roll other Opamps in with the 10M and T-pot fitted.

 My trimpot has been in place about 50 hours now and the offset has remained bang on 0.00mV per channel and hasn't drifted at all...... even if it _were_ to drift to say +/- 15mV I wouldn't be worried... there is no way you will "hear" +/-15mV.

 I'm living in Scotland and the ambient temperature of the room the WNA resides in is about 20C at the moment but I will blow a hairdryer onto the LM6171 and measure the drift (if any) an increase in ambient temperature brings about...... You could get really obsessive measuring offset under _all_ ambient operating conditions but at 20C it doesn't drift at all.... 

 I leave my WNA powered up all the time without a lid on so will monitor the offset over the next couple of months...... the past 50 hours suggests that drift is not an issue with the LM6171 and I didn't expect it to stay at 0.00mV per channel........ not even .01mV of drift! awesome.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Dont worry - I will discuss with Dr white. Tried it with the ad811 in the phono before but the drift was too high to rely on the zeroing._

 

Nick,

 Have you got your head amp yet??? Seems ages mate 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## 12796

thanks - Dr white is keeping the LM6171 in the headamp for now. I am going to compare ad843 and lm6171 in the phono and then make my decision wether or not the ad843 should be subbed into the headamp and pre. 

 Did you try the ad843 without both sets of caps and still preferred the lm6171 with one set of caps is that correct?


----------



## 12796

the headamp mods are finsihed but it is being held back while i await the ad843 to slot into the phono to test against the lm6171. Once that has been finalised david will send me both units with my choice of opamp installed. ad843 takes ages from farnell...


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Did you try the ad843 without both sets of caps and still preferred the lm6171 with one set of caps is that correct?_

 

Yes, it turned out that way Nick but I shall be building another WNA around the 843 in due course... simply rolled in the 843 sounded superb so It's worth extracting its full potential in another dedicated 843 WNA and then comparing them side to side.

 I also want to have a go at building a valve amp and maybe another Chiarra or a Dynahi so I can have a few amps on tap to compare..... 

 Mike.


----------



## boodi

Quote:


  Originally Posted by *PinkFloyd* 
_Yes, it turned out that way Nick but I shall be building another WNA around the 843 in due course... simply rolled in the 843 sounded superb so It's worth extracting its full potential in another dedicated 843 WNA and then comparing them side to side.

 I also want to have a go at building a valve amp and maybe another Chiarra or a Dynahi so I can have a few amps on tap to compare..... 

 Mike._

 

I'm looking forward to read you

 please if/when you start a new wna843 thread or a comparison thread , post a link here 
 thanks


----------



## l_simon_l

I completed my WNA headamp yesterday, and I must say it sounds awsome. But then I don't have much experience with headphone amps. The only other amp I've heard was the sugden headmaster, and it failed to impress me, but I'm very satisfied with the sound coming out of my WNA. This was the first time I've soldered anything other than cables.... this was fun, and I'm already thinking about maybe modding the amp a little and perhaps adding a simple bypassable crossfeed.

 I just have one question, It seems I have some issues with grounding. When I touch the chassis and/or volume knob I get a grounding noise. When I don't touch the amp it isn't there. Is this normal? If not, what can I do to fix it?


----------



## l_simon_l

Well now the hum is gone! Shortly after I posted my message here I got an email from david where he said he had read my post here on headfi and told me how solve my problem ( I had missed a paragraph in his manual about grounding). I must say I'm very impressed with how Dr. White treats his customers. 

 And the amp is excellent!


----------



## PinkFloyd

Quote:


  Originally Posted by *l_simon_l* 
_I completed my WNA headamp yesterday, and I must say it sounds awsome. But then I don't have much experience with headphone amps. The only other amp I've heard was the sugden headmaster, and it failed to impress me, but I'm very satisfied with the sound coming out of my WNA. This was the first time I've soldered anything other than cables.... this was fun, and I'm already thinking about maybe modding the amp a little and perhaps adding a simple bypassable crossfeed._

 

Hi Simon,

 My apologies for not congratulating you on your build sooner, I only came across your post today (I really must subscribe to this thread!) I'm glad you're happy with the amp, give it a few weeks to burn in fully it gets even better!

 If you are considering "modding" the amp then I highly recommend you remove the output caps and fit the 10M resistor and 100K trimpot.... it totally transforms the amp IMO and I would never go back to a WNA with output caps.... never! My absence from this thread the past few weeks means only one thing.... I'm happy with the amp and am enjoying the music 
	

	
	
		
		

		
			





 The WNA has remained switched on for over a month now and I've measured the DC offset almost every day and it hasn't drifted from 0.00mV (even on very warm days) so I think It's safe to say that removing the output caps and fitting 10M /100K trimmer is the way to go.


  Quote:


  Originally Posted by *l_simon_l* 
_I just have one question, It seems I have some issues with grounding. When I touch the chassis and/or volume knob I get a grounding noise. When I don't touch the amp it isn't there. Is this normal? If not, what can I do to fix it?_

 

Sorry to hear that Simon, I've just read your post saying you've managed to sort it.... It's quite a common thing but once you ground the pot to 0V it usually gets rid of it.

 Keep us updated if you do decide to mod the amp.

 All the best.

 Mike.


----------



## 12796

Arrived today! Fitted into a new case with space for 4 9V batteries (now on order). Currently running off a switchie. Pinkie - I notice there is still a single opa134 inside - is this the rail splitter? Is there anything to be gained by replacing this and what have you tried? It beats my cmoy like it was a red headed step child after the pub on a friday night. Nice bit of work you did inside! very tidy. In a months time I will be swpping in BG and vishay just to test out how much difference it makes before I consider upgrading the rest of my kit.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Arrived today!_

 

Great, at last! Sure has been gone a long time Nick.

  Quote:


  Originally Posted by *biovizier* 
_ Fitted into a new case with space for 4 9V batteries (now on order). Currently running off a switchie._

 

Cool 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *biovizier* 
_Pinkie - I notice there is still a single opa134 inside - is this the rail splitter? Is there anything to be gained by replacing this and what have you tried?_

 

So David didn't replace it with an LM6171 
	

	
	
		
		

		
		
	


	




 LM6171 is probably the best opamp to use in the railsplitter (according to brokenenglish who's compared many opamps in the rail splitter) I usually bung whatever I have into the rail splitter and on this occasion it appears the OPA134 went into yours.... perfectly good opamp for the job but you can try LM6171, OPA 627 etc. in the rail splitter and see which one you prefer. It's easy to roll the opamps in so you won't have to send the amp away.

  Quote:


  Originally Posted by *biovizier* 
_ It beats my cmoy like it was a red headed step child after the pub on a friday night. Nice bit of work you did inside! very tidy. In a months time I will be swapping in BG and vishay just to test out how much difference it makes before I consider upgrading the rest of my kit._

 

Glad you like it Nick, keep us informed if you do decide to fit black gates etc.

 All the best.

 Mike.


----------



## 12796

courtesy of a 3 week delay on ad843 due to ups! I hate those guys. 

 Think I will try lm6171, ad825, ad8065...

 I have ad843 in the phono headamp and preamp now. I just couldnt get on with the lm6171. Something just seemed to be missing and the ad843 has it. 

 I have tried ad818 and ad817 now as well - good but no threat to lm6171 / ad8065 / ad843. 

 Will keep you posted about the BG / vishay upgrade.


----------



## PinkFloyd

This one is courtesy of Rickcr42 and it most definitely is worth implementing! I originally tried it with 100R resistors but that was a misprint from Rick and should have read 10R..... I replaced the 100R's with 10R and, yes, I can detect a noticeable (not humungous) improvement in the sound...... business as usual but "cleaner" overall presentation... this is well worth a go and thanks Rick!

 Rick explains the mod: 

 "Capacitor ideally should never "see" another capacitor like the way C11 and C12 "look" directly at C5 and C6. Instead the two series connected caps should be either resistor or inductor isolated to form a high pass filter / isolation network.

 Try adding a 10 ohm 1 watt resistor series connected from C11 to C5 and from C12 to C6 and see if you hear an improvement."

 Thanks Rick, a very cost effective and extremely easy and worthwhile mod to put into the circuit


----------



## 12796

Hi,

 I am having problems with stability using the ad843 - any advice?

 Regards,

 Nick.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Hi,

 I am having problems with stability using the ad843 - any advice?

 Regards,

 Nick._

 

What kind of instability are you experiencing Nick and in what piece of equipment... the headamp?


----------



## 12796

PF,

 I have experimented with various sources and with both the headphones and the speakers. Your headamp is fine with the ad843 but the volco buffer mk 3 and phono both oscilate. The phono is worse than the volco and the osciallation isnt that severe. Consequently its nothing really to do with this thread - sorry for wasting your time! The ad843 data sheet seems to state what the problem is quite explicitly and how to solve it.

 Regards,

 Nick.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_ The ad843 data sheet seems to state what the problem is quite explicitly and how to solve it.
_

 

What was the problemo Nick? BTW, on the subject of AD843, what do you think of it?

 Mike.


----------



## 12796

PF,

 On the phono I got what I thought was hum but when you play music it starts to impose a modulation on the hum at much greater amplitude - or even if you tap the tonearm. Looking at the ad843 datasheet it needs to be tweaked to drive any capacitive load above 100 pF - and the interconnects alone I guess would be more than that, let alone the switch. There are also dc coupling caps inbetween stages 2 and 3 in the phono (both of which use ad843). Perhaps these could be cut out now I have switched away from LM6171 in the phono. I am also getting oscillation in the preamp but of a much less degree as the mk 3 has a transisitor output buffer like the mk 2 so I guess its not seeing as much capacitance. Its mainly manifesting itself as high frequency twittering and high levels of hiss as well as humming oscialltion past a certain point on the volume control. The buffer drives three balanced outputs in paralell for my triamped PMC-Bryston configuration. 

 In the phono the ad843 comprehensively trashes the lm6171 - I got that far with the cmoy (which doesnt make the phono oscilallate as badly, I just get a high level hum). Replacing the LM6171 with ad843 in the pre also made a big difference - the wiriness and sterility have gone. I havent tried the lm6171 in your headamp as I decided to go straight to the ad843 on this basis. Your headamp is clean as a whistle with no problems! No hum, inaudible hiss and no hint of oscilalation. After 2 years I have finally got the sound exactly as I want it - which obviously offends the the oscillation gods!

http://www.analog.com/UploadedFiles/...65502ad843.pdf

 This link has info about the capacitance issues and also about tweaking the circuit for the ad843 - it seems the chip might have a bit more to give in the same way that the LM6171 tweaks evolved over time. There were no problems with the ad843 in the cmoy - indeed it seemed to have a little more attack if anything and some of the notes on the link seem to pertain to rise times and pulse response - which might be relevent.

 All of my electronics experience is far enough in the past that just thinking about this makes my head hurt. I dont really want to go back to the lm6171 - theres something about it that just doesnt agree with me. Perhpas you will have a better idea of how much mileage there is in the ideas in the notes? I was hoping everything would be uncomplicated when I got the kit back - I have been without music too long already!

 Thanks for your time and understanding!

 Regards,

 Nick.


----------



## 12796

PF,

 I am thinking of trying the ad8067 in the headamp but its only stable at gains >8 - what is the defualt gain in the headamp? Also when you tried the ad8065 was that in the version of the headamp with both sets of caps?

 Thanks,

 Nick.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_As I say... you can connect to pin 4 of the LM6171 which is -12V (or near to the pin on the same track)
 Mike._

 

My suggestion - use a additional opamp for lower the DC offset.
 Some amps use a integral opamp circuit DC loopback like http://www.borbelyaudio.com/eb804419.asp
 Q9 & Q18
 This eliminates the outgoing DC and a little of ingoing offset too.


----------



## FritzS

Quote:


  Originally Posted by *FritzS* 
_My suggestion - use a additional opamp for lower the DC offset._


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_PF,

 I am thinking of trying the ad8067 in the headamp but its only stable at gains >8 - what is the defualt gain in the headamp? Also when you tried the ad8065 was that in the version of the headamp with both sets of caps?

 Thanks,

 Nick._

 

Hi Nick, 

 The gain on your amp will be the standard 4.3

 To change the gain to 9 replace the 3.3K resistor in R3 with an 8K resistor. Alternately, replace the 1K in R2 with a 500R which will give you a gain of 8.6 The gain is worked out by G = (1 + R3 / R2) 

 When I tried the AD8065 I believe the amp was capless at both ends... it was certainly tried without output caps, I can remember that.

 Mike.


----------



## 12796

I tried swapping in the ad8065 as is - it doesnt seem to be completely stable. Which is annoying as it seems as if the ad8065 might beat the ad843 - which is why I asked if you tested it capless. In the cmoy the ad8065 gave the ad843 a sound thrashing as well.


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_



_

 

Cheers Fritz!

 I put your last suggestion to Dr. White and he responded:

 "Yup that works, its called a dc servo. I'd be interested to hear from anyone who tries it, because opinion is divided as to whether it's better or worse than an output capacitor. From the various analyses I've seen I would conclude that a dc servo degrades the low bass to a greater extent than an output capacitor, but I'd be happy to be proved wrong. I considered using a dc servo in my phono stage but didn't go ahead because of the reservations outlined above."


----------



## 12796

I have completed testing the ad8065 v ad843 v ad847 in the capless WNA and also in a cmoy. The results seem pretty close:

 ad843 then ad847 then ad8065 in order of increasing performance in both amps. I would be curious to get your view in this setup Pinkie - do you have a wna amp at the moment?


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I have completed testing the ad8065 v ad843 v ad847 in the capless WNA and also in a cmoy. The results seem pretty close:

 ad843 then ad847 then ad8065 in order of increasing performance in both amps. I would be curious to get your view in this setup Pinkie - do you have a wna amp at the moment?_

 

Hi Nick,

 So you prefer the AD8065? I tried that ages ago in the Mkl and it was my second favourite to the LM6171 sounding warmer and smoother. I don't have an 8065 to hand but will try and find the thread where I commented on it... will link to it when I find it.

 Mike.


----------



## PinkFloyd

Here you go nick:

AD8065 2


----------



## rickcr42

The AD843 may be getting a bit long in the tooth (old) but still manges to get more right than it does wrong.I also like the "old" AD825 chip which again usually errs on the side of musical rather than the trend of most "newer" more modern chips which always seem to trend to the bright and slashy when caught out on busy sections of music with a lot of peak content in combination with a low level music foundation.They seem to lose the low level details while attempting to hit the massed peaks but fail even there mostly.

 Just an opinion of course.YMMV.

 On to servoed designs.I do not like them personally even though many swear by them.The servo in combination with negative feedback to me is a stage alwys trying to catch up and perfect instead of just passing along what is there.Play,compare,eliminate.play,compare,eliminat e,play,compare....... 
	

	
	
		
		

		
		
	


	



 With a discrete output stage DC coupling is attainable but again no eeasy path and there is parts aging which will cause at some point a D.C. offset requiring re-adjustment.this last is not within the capabilities or desire range of most headphone users so would be out for a commercial product but even for the DIYer who would want to always be paranoid about the D.C. and instead of enjoying music worrying about his and checking for D.C. conmtent ?

 So what is left ? Capacitor coupling or transformer galvanic isolation.The first is the cheaper path and one that can provide good results depending on the capacitor selected.Being a single part it is super easy to pop out one cap and pop in another to check the sonics and once you arrive at a good result-solder that puppy in and close up the box then go enjoy some music.
 The second option is neither cheap nor is there many oiptions out there though why i do not know considering the amount of headphone amp activity lately from all the major players.Sowter has one that goes dead flat from 15hz-30khz and is 10 ohms effective as seen by the circuit so a possible solution but to my knowledge the only headphone specific transformer readily available.Oh you,it will cost about 10X the cost of even the most expensive caps so not a cheap option though potentially a better option sonically.

 Just adding to the conversation folks


----------



## rickcr42

BTW-a D.C. Servo done right is not run full banwidth but is low pass filtered so it only effects the below audible range frequencies.Probably start it around 5hz and flat to D.C. (0.1hz).This means the opamp used for the servo must have superior low frequency response itself and not just grab any and stick it in.You also do NOT want an ultra-high-speed lightening fast/high slew rate device.These frequencies where it will be used are neither fast nor are they ultrasonic so if the stage is limited to the narrow band where it is to do the work again it is D.C and low frequency performance thatdetermines suitability.

 I think the OP27 worth looking into for this area.


----------



## 12796

Pinkie,

 Well the ad8065 in the Mk II with both lots of caps removed (and series resistor on the output replaced with zobel compared with Mk I and no resistor accross pins 2 and 6) doesnt sound warm or smooth at all as far as I can tell. It doesnt get confused sounding either. It just sounds exactly right. According to Dr White it was a close call between ad843 and lm6171 in my headamp - and Mrs White prefered the ad843, so the ad8065 should be a long way ahead. Look forward to hearing your findings with your next headamp! Do you have a wna unit currently?

 Regards,

 Nick.


----------



## PinkFloyd

Hi Rick,

 The two 10M resistors and 100K work fine and the DC offset stays at 0.00mV whatever the ambient temperature so I don't see the need for a DC servo... sometimes the simple "cheap" way is the best way. Since removing the output caps and zeroing the offset by means of the 10M and 100K trimpot the amp has never sounded better and I just am happy to listen to the music... you can spend ages messing around with components and find yourself listening to the amp instead of listening to the music. I am, once again, listening to the music (and enjoying it) and for the first time in _ages_ I am frightened to go under the bonnet and change anything in case I mess up this glorious sound I'm enjoying.

 I've been listening with the Marantz CD-10 Trichord modded CDP and Grado SR-325i and am pretty bowled over by just how "analogue" like this combo sounds..... The WNA is typically "British sounding" and excels in the timing and detail departments and doesn't seem to over emphasise things like some of the "beast" amplifiers do..... It's just sounding so neutral which I love! It doesn't grab you by the balls and inject spadeloads of excitement into your ears (Spadeloads of excitement is good for a 5 minute listen but that soon turns to fatigue) no this little puppy sounds unexciting on initial listen, It's only after you've heard her for a few hours that you realise this unassuming, seemingly flat sounding amp is doing the right thing..... there are no bells and whistles attached to this amp just good old down to earth "music" is outputted with nothing added and nothing subtracted.... acoustic guitar sounds like acoustic guitar and not like a bouzouki, bass lines sound like musically individual notes and not like someone farting low level into a microphone, rim shots are like someone firing an ouzo SMG and not like someone firing peas out of a pea shooter, vocals are silky smooth and not searingly sibilant and well recorded live concerts come across as palpable and sized to scale and not puny and compressed sounding.

 This is slightly off topic but I, for one, just had to say I'm enjoying the music and have no intention of doing any more to this amp. It's a super DIY amp in stock (kit form) guise but It's a very great amp once you remove the belt and braces (bullet proof) components from it. I'll say it again.... compared with Graham Slee Solo, MF X-Can V2 (modded), Chiarra / Andante and Sugden Headmaster the WNA blows them into the dust when it comes to sound quality..... I can't wait for a MKlll (if there will ever be such a thing?)

 Keep up the good work Dr. White.

 Mike.


----------



## 12796

Its funny you should mention that ... my new version of the volco has something very interesting under the hood!


----------



## rickcr42

Quote:


 sometimes the simple "cheap" way is the best way 
 

more like all the time.so many spend far too much time trying to over think a problem that the solution is often worse than what they were trying to fix.

 "the operation was a total success but the patient died"


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Its funny you should mention that ... my new version of the volco has something very interesting under the hood!_

 

Sounds interesting


----------



## 12796

Indeed - I am test driving a new prototype. Both the headamp, the cmoy and the prototype seem to work best with the ad8065. 

 Ad847 also beats the ad843 - not quite as good as the ad8065 but fortunately its stable in the phono (stages 2 and 3) so that solved that particular problem. I am trying out half a dozen other opamps... ad810, ad829, ad8021, ad8067 etc so will keep you posted. Some of them are low noise so I can use them to replace the lm6181 in the phono front end.

 ad817 and ad818 didnt sound that good.


----------



## StevieDvd

Where do you get your opamps from?

 I've been looking at some of the AD ones to use try in my Supermacro V3 but the places I try say that they will have to come from USA with an OTT postage cost.

 Steve


----------



## 12796

I got some from farnell and some from samples. I will have about a dozen spare ad843 soon if you want some. Also some ad825 and a few other bits and pieces. Some I gave to David but they werent very good. 

 Fiver each sound ok for the ad843?


----------



## StevieDvd

Quote:


  Originally Posted by *biovizier* 
_I got some from farnell and some from samples. I will have about a dozen spare ad843 soon if you want some. Also some ad825 and a few other bits and pieces. Some I gave to David but they werent very good. 

 Fiver each sound ok for the ad843?_

 

Sounds 
	

	
	
		
		

		
		
	


	




 great. I can do Paypal, cheque or bank transfer. Drop me a PM with your preference and details plase.

 Thanks

 Steve

 PS what part of London are you in (work, home or both)?


----------



## FritzS

Another suggestion - power from Ultracapacitors.
 Loading the Ultracapacitors if not hearing and power off the main power supply when hearing.

 Maxwell Technologies Ultracapacitors
http://www.maxwell.com/ultracapacitors/
http://www.maxwell.com/ultracapacito.../BCAP0350.html


----------



## 12796

work - mayfair

 home - camden.

 I have 2 ad825 but they will need mounting and about 13 ad843 - once I get the rest of the ad8065 and ad847 in. I have 7 available right now. I did have some others but sent them to david - ad797, ad817, ad818 - but they are nowhere enar as good as the ad843. Only the ad847 and ad8065 are as good or better than the ad843. 

 How many do you need and what are you using them for?


----------



## StevieDvd

Quote:


  Originally Posted by *biovizier* 
_work - mayfair

 home - camden.

 I have 2 ad825 but they will need mounting and about 13 ad843 - once I get the rest of the ad8065 and ad847 in. I have 7 available right now. I did have some others but sent them to david - ad797, ad817, ad818 - but they are nowhere enar as good as the ad843. Only the ad847 and ad8065 are as good or better than the ad843. 

 How many do you need and what are you using them for?_

 

They are for my XIN Supermacro V3 (SM3), currently have OPA627 fitted and have tried a few others (AD797, NE5334, SA5334, OPA604) thought I'd try the AD843s as I'd read they were supposed to be OK.

 Barring bomb alerts I work in the city and it's nice to know where in the UK out head-fi guys are located. 

 I'd need a pair for the SM3 (8 pin dip to plug in to socket of SM3) so a couple of AD843 would be great to try.

 Steve


----------



## 12796

ok pm me privately with details and we will get the ball rolling


----------



## spendorspain

Hi, rickcr42. 

 In a previous post you said about dc offset nulling: "So what is left ? Capacitor coupling or transformer galvanic isolation.The first is the cheaper path and one that can provide good results depending on the capacitor selected.Being a single part it is super easy to pop out one cap and pop in another to check the sonics and once you arrive at a good result-solder that puppy in and close up the box then go enjoy some music."

 So, regarding DC offset and capacitor coupling... Could you tell me what (value, type, brand) output capacitors do you use? If I'm not wrong, you drive Grado cans with a WNA hp amp (a MkII or MkI?), a pairing very much like mine (although perhaps the sonic balance of my HP-2 is quite different from the RS-1; I don't know much about Alessandro cans, other than they are derived from Grados). Have you any experience with different types or brands of caps for dc-coupling?. I'm sure the choice of this part is critical for the best sonic quality in WNA hp amp. I use Black Gate 1000uF/25V Nx Bipolar as output caps, but any suggestion would be interesting.

 Regards
 Jose


----------



## 12796

Where did you get your transistor heatsinks in the headamp pinkie? How much were they?

 Regards,

 Nick.


----------



## 12796

does anyone know where to get a sot23-5 to dip-8 adapter - I want to try ad8067 in the headamp...


----------



## FritzS

Quote:


  Originally Posted by *bludragon* 
_63-1744330K20.250.59 - The feedback distributor
 63-100010R20.250.59 - The Zobel Network
 62-2550100R11.802.12 - Increase the quiescent Current (pack of 100)
 62-2560160R11.802.12 - Increase the quiescent Current (pack of 100)
 08-0940100pF100.070.82 - extra psu decoupling
 08-0945220pF100.070.82 - extra psu decoupling
 11-3636470µF100.333.88 - extra psu decoupling
 10-1340100nF40.160.75 - The Zobel Network (you only need 2 - also not sure if these are the best type for this purpose)
 36-0198Type TV4 SOT32120.395.50 - Increase the quiescent Current

 Came to a total of a not so insignificant £21.24 with delivery._

 

from which distributor? I life in Austria/Europe


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_I've only tried the cerafines in the WNA to very good effect, I'll let you know how the fine golds sound as soon as I put together my WNA. 
 Mike._

 

from which distributor have you got the Nichicon fine gold - and the Black Gate 1000 myF non polar too? I life in Austria/Europe


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Where did you get your transistor heatsinks in the headamp pinkie? How much were they?

 Regards,

 Nick._

 

Hi Nick,

 Sorry for the delay I've been a bit off the ball for a while. the clip on ones  are from Rapid, are these the ones that are in your amp? Even better are these  from Maplin but you may find you need to use a mixture of both dependant on space in the amp. If you look at your heatsinks you'll notice I've clipped little chunks out of the bottom of a couple of them to clear the resistors. Any of these two heatsinks are great for the WNA though.

 Best.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_from which distributor have you got the Nichicon fine gold - and the Black Gate 1000 myF non polar too? I life in Austria/Europe _

 

Hi Fritz,

 I got mine from fellow Head-Fier JMT. I'm not sure if he has any left but, if he doesn't, I'm sure he will advise you where you can source them.

 Actually percyaudio do them  for 70c a pop and they ship worldwide.

 Hope this is of help Fritz.

 All the best.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_does anyone know where to get a sot23-5 to dip-8 adapter - I want to try ad8067 in the headamp..._

 


These guys will make you one up I'm sure


----------



## FritzS

Quote:


  Originally Posted by *FritzS* 
_from which distributor have you got the Nichicon fine gold ...._

 

Nichicon KZ series are higher grade than Nichicon FG (fine gold)!?
http://www.nichicon.co.jp/english/seihin/pdfs/e-fg.pdf
http://www.nichicon.co.jp/english/seihin/pdfs/e-kz.pdf
 the data sheets says "yes"


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Nichicon KZ series are higher grade than Nichicon FG (fine gold)!?
http://www.nichicon.co.jp/english/seihin/pdfs/e-fg.pdf
http://www.nichicon.co.jp/english/seihin/pdfs/e-kz.pdf
 the data sheets says "yes" 
	

	
	
		
		

		
		
	


	


_

 


 Hi Fritz,

 The MUSE (KZ) are good caps also and are probably more popular than the Fine Gold when it comes to audio though the FG do sound very nice indeed.

 Mike.


----------



## 12796

Hows it going with your headphone amps pinkie - any further progress on the wna. you seem to be very quiet recently - hope everything is ok.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Hows it going with your headphone amps pinkie - any further progress on the wna. you seem to be very quiet recently - hope everything is ok._

 

Hi Nick,

 Thanks for asking. I have been pretty quiet on the amplifier front of late, the WNA is sounding splendid so there's no reason for me to continuously piss about with it...... I did cut a hole in the top of the enclosure and spanned it with some wire mesh to act as a ventilation hole cum peephole, I fitted an internal Green LED and It's pretty nifty at night as it throws out a lovely green glow from the top of the amp and also projects a far out pattern of green onto the ceiling. 

 It was one ugly pug of an amp in that ten a penny Hammond enclosure but the little hole, mesh, internal green LED and oversized volume knob have made it look a little more funky. DC offset still measures zero after all that time so the trimpot and 10M alternative to the output caps is 100% cool and if WNA ever make a MKlll I hope they make provision on the PCB for this.

 Here's a few pics of my "Hole"

 All the best.

 Mike.





 The Hole spanned with grey wire mesh 





 Another view of the hole





 Illuminated vent. Picture really doesn't do this justice!





 Hole from another angle





 More hole





 Belly up


----------



## 12796

looks smart - which chip are you using these days? I can send you a couple of ad843 to try if you want.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_looks smart - which chip are you using these days? I can send you a couple of ad843 to try if you want._

 

Cheers Nick,

 I've got quite a few AD843. Using the LM6171 throughout (minus 330K feedback distributor) and enjoying the music 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_I've got quite a few AD843. Using the LM6171 throughout (minus 330K feedback distributor) and enjoying the music 
	

	
	
		
		

		
		
	


	



 Mike._

 

Whats the sound difference to LM6171?
 What modifications are you made too?
 Bypass caps to electrolytic caps?
 Zobel filter - polypropylen or polyester caps?
 Coupling capacitors modified?
 Lamp replaced with resistor?
 etc.


----------



## FritzS

Quote:


  Originally Posted by *FritzS* 
_ what your experience about Nichicon "fine gold" vs. Elna Cerafine vs. Blackgate (Rubicon) in PSU or in signal path?_

 

David tells me there are Rubycon ZA's in the current kit.
 The resistors are Welwyn RC55Ys, the film capacitors are polypropylene.

 Have anyone experience about Nichicon "fine gold" vs. Rubycon ZA's


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Whats the sound difference to LM6171?_

 

Hi FritzS,

 I haven't been doing much listening of late but an earlier impression of the AD-843 is here It's a pretty close run thing between the LM6171 & AD-843 but I ended up sticking with the LM6171 (without output caps) in the end..... Give the 843 a try you might like it 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *FritzS* 
_ What modifications have you made too?_

 

Nothing too drastic over the standard MKll kit I just replaced the lamps with ferrite bead inductors (or zero ohm links), fitted a zobel network, removed the output caps and fitted a 10M resistor & 100K trimpot to trim the DC offset to zero. 

  Quote:


  Originally Posted by *FritzS* 
_ Bypass caps to electrolytic caps?_

 

Yes I bypassed the electrolytics with polypropylene and polyester film caps. Can't remember the exact values but it was something like 220pF (polyprop) and a 220nF polyester..... I was going to try higher value film caps but haven't got around to it yet. 

  Quote:


  Originally Posted by *FritzS* 
_Zobel filter - polypropylen or polyester caps?_

 

I just used 100nF polyester Fritz

  Quote:


  Originally Posted by *FritzS* 
_Lamp replaced with resistor?_

 

Yes, zero ohm resistor or a ferrite bead inductor. I used axial ferrite bead inductors.

  Quote:


  Originally Posted by *FritzS* 
_ etc._

 

I've probably missed a few things out, I haven't had my mind on audio for a while so It's hard to remember every little tweak, but I'm doing my best to get my mind back into this hobby (and a few other things) and will hopefully be firing on all 4 cylinders and messing about with capacitors and things soon


----------



## 12796

... significantly better than ad843! As is the ad8065 with caps removed...


----------



## PinkFloyd

Must give it a go at the same time as the 797


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_I haven't been doing much listening of late but an earlier impression of the AD-843 is here It's a pretty close run thing between the LM6171 & AD-843 but I ended up sticking with the LM6171 (without output caps) in the end..... Give the 843 a try you might like it 
	

	
	
		
		

		
		
	


	


_

 

With the 4,7 uF polypropylene input caps?
 But without output caps, there is no DC fault protection for the headphones?

  Quote:


  Originally Posted by *PinkFloyd* 
_Nothing too drastic over the standard MKll kit I just replaced the lamps with ferrite bead inductors (or zero ohm links), fitted a zobel network, removed the output caps and fitted a 10M resistor & 100K trimpot to trim the DC offset to zero. _

 

For use Sennheiser HD 600 I will put a little 8 to 10 Ohm 1W resistor (or two 20 Ohm in parallel + ferrite bead inductors) in series for short-circuit protection - the damping factor is high enough.

  Quote:


  Originally Posted by *PinkFloyd* 
_Yes I bypassed the electrolytics with polypropylene and polyester film caps. Can't remember the exact values but it was something like 220pF (polyprop) and a 220nF polyester..... I was going to try higher value film caps but haven't got around to it yet. 
I just used 100nF polyester Fritz_

 

I will do this too.
 Today I wrote David about order and shipping details ....

 What solder are use you - a alloy with argent, copper, tin, lead?


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_With the 4,7 uF polypropylene input caps?
 But without output caps, there is no DC fault protection for the headphones?_

 

Yes, with 4u7 polypropylene input caps. The DC is offset to "Zero" thanks to the 10M resistor / 100K trimpot so there is no DC going into the headphones. Obviously, if the 10M resistor was to drop off or something then DC would reach the headphones but the same thing would also happen if the output capacitors failed.... as long as the trimpot and 10M are very securely connected and the offset trimmed to zero then there should never be a problem with DC reaching the 'phones. 


  Quote:


  Originally Posted by *FritzS* 
_For use Sennheiser HD 600 I will put a little 8 to 10 Ohm 1W resistor (or two 20 Ohm in parallel + ferrite bead inductors) in series for short-circuit protection - the damping factor is high enough._

 

You'd be just as well leaving the incandescent lamps in place. They act as current limiters which reduce opamp and driver stage dissipation in the event of a short circuit caused by, for example, frayed headphone leads. 12V 60mA lamp is suitable in most cases. The lamp resistance measures 22 ohm and I have found the amp sounds a bit better with these protection devices removed and replaced with zero ohm links...... you can, of course, fit the industry standard 120 ohm output resistor in this position or fit a zero ohm link or just stick with the default 22 ohm 12V 60mA incandescent lamp, It's up to you 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *FritzS* 
_Today I wrote David about order and shipping details ...._

 

oops.... I thought you already had a kit Fritz...... It will become a _*lot*_ clearer when you read the construction manual..... everything in this thread is covered in the manual and it is written very well and is extremely easy to understand.

  Quote:


  Originally Posted by *FritzS* 
_What solder are use you - a alloy with argent, copper, tin, lead?_

 

I just use bog standard 60 / 40 Fritz (Tin / Lead) Soon to be illegal here so I'm stocking up on it 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Yes, with 4u7 polypropylene input caps. The DC is offset to "Zero" thanks to the 10M resistor / 100K trimpot so there is no DC going into the headphones. Obviously, if the 10M resistor was to drop off or something then DC would reach the headphones but the same thing would also happen if the output capacitors failed.... as long as the trimpot and 10M are very securely connected and the offset trimmed to zero then there should never be a problem with DC reaching the 'phones._

 

With output caps it must be two failures, a higher DC offset and a bypass in output caps. Have you test electrolytic and polypropylene (or polystrene) caps in parallel?


  Quote:


 You'd be just as well leaving the incandescent lamps in place. They act as current limiters which reduce opamp and driver stage dissipation in the event of a short circuit caused by, for example, frayed headphone leads. 12V 60mA lamp is suitable in most cases. The lamp resistance measures 22 ohm and I have found the amp sounds a bit better with these protection devices removed and replaced with zero ohm links...... you can, of course, fit the industry standard 120 ohm output resistor in this position or fit a zero ohm link or just stick with the default 22 ohm 12V 60mA incandescent lamp, It's up to you 
	

	
	
		
		

		
			




 

So I will use a (fuse)resistor, value between 8 ... 22 ohm, momentary it will limit the current. For my Sennheiser HD 600 industry standard 120 ohm output resistor is not recommended. It gives another way - to use diodes to limit the voltages between B and E+resistor of the output transistors and so limit the outgoing current. This is standard in the most amplifiers but discussed controversial.

  Quote:


 oops.... I thought you already had a kit Fritz...... It will become a _*lot*_ clearer when you read the construction manual..... everything in this thread is covered in the manual and it is written very well and is extremely easy to understand. 
 

now its a question of time 

  Quote:


 I just use bog standard 60 / 40 (Tin / Lead) Soon to be illegal here so I'm stocking up on it 
	

	
	
		
		

		
		
	


	




 Mike. 
 

Some use a peace of 3% silver for high end 
	

	
	
		
		

		
		
	


	




 But lead can use still 1 ... 2 years - I have a lot of standard 60 / 40 Tin / Lead with 1 mm or 0,7 mm diameter.


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_With output caps it must be two failures, a higher DC offset and a bypass in output caps. Have you test electrolytic and polypropylene (or polystrene) caps in parallel?_

 

Yes, I tried non polar electrolytics bypassed with polyprops (in parallel) but to be perfectly honest "no output" capacitor is best as far as sound quality is concerned....... removing them and fitting 10M and 100K trimpot is simple:






 On both *IC1* LM6171's ([size=medium]don't[/size] do this on IC2) Connect the track of a 100k trimmer potentiometer between 0V (ground) and -12V then connect a 10M resistor between the slider of the trimpot and pin 3 of the LM6171. Adjust the trimpot for minimum offset, run for 30mins or so then readjust offset to zero..... Once it is set to zero it doesn't drift at all 
	

	
	
		
		

		
		
	


	




 You _[size=large]must[/size]_ have 4u7 input caps in place if you're doing this.





 100K trimpot & 10M in place...... output caps removed.


----------



## FritzS

Dear PinkFloyd!
  Quote:


  Originally Posted by *PinkFloyd* 
_100K trimpot & 10M in place...... output caps removed._

 

 What value has the resistor instead of C4?

 4,7 uF (C1) - you use RIFA PHE 426, Dr.White gives "orange caps" in his kits, but I will test Axon caps (varying bypassed with polystyrene caps) in this place. 

 Did you replace R5 with 160 Ohm and R6 with 100 Ohm - to increase the quiescent current?

 For all other electrolytic caps I will use Nichicon FG (fine gold) and bypassed as described in this thread.

  Quote:


 Dr. White responds: ..... As I mentioned to you a couple of times previously I'm in the process of upgrading my loudspeaker protection unit to cater for headphones ( this preceded ambs unit ). The pcb design is now complete and kits should be available in 3-4 weeks time. .... 
 

 Have anyone seen this kit?

  Quote:


 Rick explains the mod: 
 "Capacitor ideally should never "see" another capacitor like the way C11 and C12 "look" directly at C5 and C6. 
 Instead the two series connected caps should be either resistor or inductor isolated to form a high pass filter / isolation network.
 Try adding a 10 ohm 1 watt resistor series connected from C11 to C5 and from C12 to C6 and see if you hear an improvement." 
 

 Have you done this? 
 What ist the greatest recommended value for C11 & C12 without damage Tr.7 & Tr. 8?

 Questions over questions 
	

	
	
		
		

		
		
	


	




 but the answers are important for me - I will order some components from Michael Percy. 
	

	
	
		
		

		
		
	


	




 PS: What the difference in sound between the rail split PSU design and a conventional +-12V(15V) stabilized PSU?

 PPS: "Off topic" - what the sound difference between the WNA MKII and the X-Can V2 (with Capacitor Upgrade)?


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Must give it a go at the same time as the 797 
	

	
	
		
		

		
		
	


	


_

 

From all the 797, 843, 847 - are you back to 6171?


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Dear PinkFloyd!
 What value has the resistor instead of C4?_

 

Zero ohm resistor Fritz (or a wire jumper)

  Quote:


  Originally Posted by *FritzS* 
_4,7 uF (C1) - you use RIFA PHE 426, Dr.White gives "orange caps" in his kits, but I will test Axon caps (varying bypassed with polystyrene caps) in this place._

 

Orange caps?? Dr. White has _always_ supplies 4u7 polypropylene RIFA PHE 426 capacitors (the blue ones) with the kits. I have used polyester (orange caps) a couple of times but the WNA kit is supplied with high quality RIFA PHE 426 caps. 

  Quote:


  Originally Posted by *FritzS* 
_Did you replace R5 with 160 Ohm and R6 with 100 Ohm - to increase the quiescent current?_

 

No, not in my latest amp. I left the quiescent current as standard.

  Quote:


  Originally Posted by *FritzS* 
_For all other electrolytic caps I will use Nichicon FG (fine gold) and bypassed as described in this thread._

 

Nichicon, ELNA cerafine / silmic etc. you won't go wrong 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *FritzS* 
_ Have anyone seen this kit?_

 

WNA do supply a headphone protection circuit kit and I think it costs around £25 (don't quote me on that) but best to check with WNA for full details.


  Quote:


  Originally Posted by *FritzS* 
_What is the greatest recommended value for C11 & C12 without damage Tr.7 & Tr. 8?_

 

I wouldn't go above 220uF.... I tried 1000uF and it melted the transistors and took out the constant current diodes. 100uF is supplied with the kit but you can go up to 220uF safely.

  Quote:


  Originally Posted by *FritzS* 
_PS: What the difference in sound between the rail split PSU design and a conventional +-12V(15V) stabilized PSU?_

 

Haven't got a clue, I always use a 24V psu into the rail splitter which gives -12V 0V +12V into the amp.

  Quote:


  Originally Posted by *FritzS* 
_PPS: "Off topic" - what the sound difference between the WNA MKII and the X-Can V2 (with Capacitor Upgrade)?_

 

The WNA MKll is better defined than the modded V2 and is, quite frankly, in a different league sound quality wise...... much better across the board.


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_From all the 797, 843, 847 - are you back to 6171? 
	

	
	
		
		

		
		
	


	


_

 

Haven't tried the 847 as yet but I prefer the LM6171 over the other opamps I have tried.


----------



## 12796

theres a new kid on the block pinkie - the ad8067. the king is dead - long live the new king!


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_theres a new kid on the block pinkie - the ad8067. the king is dead - long live the new king!_

 

Blimey Nick, at this rate of rolling you'll wear your dip8 socket out


----------



## 12796

The ad8067 uses sot23-5 dip-8 adapter. No wear on my socket mate! Its the last of the bunch to try...


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_The ad8067 uses sot23-5 dip-8 adapter. No wear on my socket mate! Its the last of the bunch to try..._

 

Have you tried it in the headamp or just in your phono stage?


----------



## 12796

I have bought enough adapters to do all three (headamp, volco, phono) - David is attempting to get it stable in the headamp currently. It already mashes the ad843 / ad847. Will keep you posted!


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I have bought enough adapters to do all three (headamp, volco, phono) - David is attempting to get it stable in the headamp currently. It already mashes the ad843 / ad847. Will keep you posted!_

 

Oh blimey, not another prima donna like the LM6171 I hope 
	

	
	
		
		

		
		
	


	




 have a try with the [size=x-large]797[/size] in your phono Nick........ you may be _*pleasantly*_ surprised 
	

	
	
		
		

		
		
	


	




_*The [size=large]AD797[/size] is a very low noise, low distortion operational amplifier [size=medium]ideal [/size] for use as a [size=medium]preamplifier[/size]. The low noise of 0.9 nV(root)Hz and low total harmonic distortion of -120 dB at audio bandwidths give the AD797 the wide dynamic range necessary for [size=medium]preamps[/size] in microphones and mixing consoles. Furthermore, the AD797's excellent slew rate of 20 V/µs and 110 MHz gain bandwidth make it highly suitable for low frequency ultrasound applications. * _


----------



## 12796

Already tried the ad797 - it was pretty good. But the lm6181, ad811, ad829 and ad8021 were better in the first stage. The ad847, ad843, lm6171 were better in the 2nd and 3rd. The ad8067 beats all of them in every position but is a bit noisy. 

 Bizarrely the ad8067 is more stable than the ad8065 in the phono which just didnt work at all - which is odd as it is just a decompensated AD8065. The ad8067 needs a gain of 8 or a few tweaks to be stable lower than that. It has a compensation pin and you can also try cap in the FB loop or a load resistor. 

 Apparently the sound is rock solid and crystal clear - cant wait to hear it take on the lm6171 in the headamp. Dont take the lm6171 name in vain - David might hear you!


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_ The ad8067 beats all of them in every position but is a bit noisy. _

 

Well, if it's noisy how the heck can it beat all the other opamps?


----------



## 12796

Ah sorry its 6 nV/root hz. This is only "noisy" as far as the phono first stage is concerned. Its still not too bad though. Its still much quieter than the lm6171. Just not as quiet as the ad797. I find the extra dynamics offset the extra noise to a certain degree. The quietest opamp I have found is the ad811. The CFB operation means the overall noise is lower for an MC cartridge than the ad797 even though the voltage noise figure is similiar.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Ah sorry its 6 nV/root hz. This is only "noisy" as far as the phono first stage is concerned. Its still not too bad though. Its still much quieter than the lm6171. Just not as quiet as the ad797. I find the extra dynamics offset the extra noise to a certain degree. The quietest opamp I have found is the ad811. The CFB operation means the overall noise is lower for an MC cartridge than the ad797 even though the voltage noise figure is similiar._

 

My apologies I thought you were referring to "audible" noise.


----------



## 12796

Sorry I should have been more precise. 

 I have a low o/p moving coil - 0.2 mV so 6-8 nZ is audible at high volume but not intrusive. Ideally I would like a low noise CFB version of the ad8067 to make things absolutely perfect! Such chips exist but the phono is +/- 12v and the XFCB ad chips with low noise only operate +/-5V. 

 Will keep you posted!


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_
 Will keep you posted!_

 

Please do


----------



## FritzS

Quote:


  Originally Posted by *FritzS* 
_So I will use a (fuse)resistor, value between 8 ... 22 ohm, momentary it will limit the current. For my Sennheiser HD 600 industry standard 120 ohm output resistor is not recommended. It gives another way - to use diodes to limit the voltages between B and E+resistor of the output transistors and so limit the outgoing current. This is standard in the most amplifiers but discussed controversial._

 

Walt Jung describe a flexible Class A buffer in 
http://www.elecdesign.com/Globals/Pl...tent/2800.html
http://www.elecdesign.com/globals/pl...mages/2801.gif
 and a protection
  Quote:


 Walt Jung .... Protection of this circuit is provided by several means. Without D3 and D4, the upper current limit for Q3-Q4 is set either by the limited-drive current (5 mA) times the gain (50 to 250), or by the R6-R8 values and the supplies. This current can easily reach several hundred mA, so active current limiting is very useful. The optional Red LEDs D3 (D4) provide this, clamping the drive to Q3 (Q4) when the emitter current reaches about 1.2/R6, or ~240 mA as shown. For lower levels, the LEDs don't conduct and signals pass normally. The LEDs are Panasonic types as noted. 
 

I mean this design


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Already tried the ad797 - it was pretty good. But the lm6181, ad811, ad829 and ad8021 were better in the first stage. The ad847, ad843, lm6171 were better in the 2nd and 3rd. The ad8067 beats all of them in every position but is a bit noisy. 

 Bizarrely the ad8067 is more stable than the ad8065 in the phono which just didnt work at all - which is odd as it is just a decompensated AD8065. The ad8067 needs a gain of 8 or a few tweaks to be stable lower than that. It has a compensation pin and you can also try cap in the FB loop or a load resistor. 

 Apparently the sound is rock solid and crystal clear - cant wait to hear it take on the lm6171 in the headamp. Dont take the lm6171 name in vain - David might hear you!_

 

Have you tried any of the single TI chips apart from the 134 and 627 Nick? I've just ordered up some 227, 228, 604 and 637 to give them a whirl under the bonnet.

 I know from past experience that the 2227 / 2228 / 2604 duals are very nice sounding chips so the same should be the case with the singles.... I'll keep you posted and may well even get serious and do a shootout and write up of all the chips I have at my disposal...... It's about time I put my extra 150mb of web space to good use and September is always the time I get excited about all things "audio" so I'll don my listening cap, arm myself with a notepad and get down to some serious listening and will then update this seriously lame page





 Obviously the page will be renamed "WNA grand op-amp test" or I may even dedicate a brand new page to the WNA opamp grand shootout 
	

	
	
		
		

		
		
	


	




 You can send me your opamp impressions and I'll add them also, always best to have a second unbiased opinion.

 Yeeeeeeeehaw! My audio juices are starting to flow again 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## 12796

Yes I tried the opa637 - better than opa627 but still didnt like it much. It seems I just like the AD sound. 

 I will get a mop ready!


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_
 I will get a mop ready!_

 

You better make it a supermop! I will have spare opa227 and opa228 if you want to try them Nick. As I say, we can both take notes on lots of opamps and I can publish our (independent) findings along with scores (out of ten) on a webpage for all to see...... It's up to you, if you'd like to take part in the WNA grand opamp shootout then let me know and we can organise some reference listening material, a selection of opamps to be compared and headphones we will listen with...... I propose to do this sometime in September.

 Mike.


 For starters I have the following at my disposal:

 OPA227
 OPA228
 OPA627
 OPA637
 OPA134
 OPA604
 AD843
 AD797
 LM6171
 LM6181
 AD811
 AD8610
 AD8065

 and a few others......


----------



## 12796

Sounds great!

 Taking the caps out makes a difference for the ad chips as well - the ad8065 sounds fab in the headamp without them.

 I have a pair of spare ad8067 if you want them. 

 I have tried quite a few opa chips now and didnt like any of them so will pass on that offer. 

 I suggest we wait until I have ad8067 fitted in the headamp along with BGs and vishays. My headamp is running on battery power now so I can compare that with psu. 

 I am using akg k340, beyer dt231 and akg k271.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Sounds great!

 Taking the caps out makes a difference for the ad chips as well - the ad8065 sounds fab in the headamp without them.

 I have a pair of spare ad8067 if you want them. 

 I have tried quite a few opa chips now and didnt like any of them so will pass on that offer. 

 I suggest we wait until I have ad8067 fitted in the headamp along with BGs and vishays. My headamp is running on battery power now so I can compare that with psu. 

 I am using akg k340, beyer dt231 and akg k271._

 

I'd love to try the 8067 Nick. From my experience the WNA is not too good at driving the K-340, I actually sold my K-340 as the WNA didn't provide them with the necessary "grunt" required to bring the best out of them.... the old X-Can V2 and Chiarra did a better job with them but that's another story. It could also be the case that my K-340's had lost their charge (AKG technician reckons they start to lose charge after about 15 years)

 Tried the 271 but found them very honky, closed and rubbery sounding so I will be testing with HD-600 and K-501 (again, the WNA doesn't do a great job of driving the K-501 but it's good enough to test opamps with) I may buy the 50 ohm HD-595 and give them a go too but for the test I'll probably use the HD-600 as the main reference 'phones s they are a good jack of all trades headphone.

 You've removed the output caps but have you fitted the 10M resistor and 100K trimpot? This is pretty essential to get the DC offset down to 0.00mV. If you read through the MKl thread you'll see that the 8065 was my second favourite to the LM6171 and that was "with" output caps so I imagine they'll sound even better without them...... must give them another shot!

 Going to try the AD843 again later today, the last time I tried them was with output caps and they sounded bloody great in the headamp so let's see how they fare without output caps and 0.00mV DC offset.

 Just out of interest Nick, what position on the volco do you listen to the K-340's at? IIRC I had to crank the WNA up to 2 o'clock to get anything decent out of them and, even then, they sounded thin compared to the X-Can V2 which would drive them beautifully (and the K-501) at any level and really make them shine (specially in the bass department) K-340 are superb 'phones Nick (the first proper pair I bought many many years ago) but they really need an amp with "grunt" to bring the best out of them IMO.... how do you find them with the WNA <be honest!>

PS: here's a few pics of my trusty old K-340's





 Mike.


----------



## 12796

I use the akg271 in the gym - they are great for that. 

 I find the akg 340 is fine - however there are numerous different versions. I whack it up to about 2pm as well. I am not using caps or trimpots with the ad8065. If you fitted the 100M resistor then I think it is still on there. Where should I look? Maybe David tweaked it for the akg when isent it to him. 

 I have a bare pair of ad8067 - they are sot23-5 so you need a custom adapter from wilmslow adaptics. About a fiver each. I dont have any spare ones. 

 I look forward to hearing about ad843 and ad8065 without the caps - the ad8067 is sure to be better even than that!


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I use the akg271 in the gym - they are great for that. 

 I find the akg 340 is fine - however there are numerous different versions. I whack it up to about 2pm as well. I am not using caps or trimpots with the ad8065. If you fitted the 100M resistor then I think it is still on there. Where should I look? Maybe David tweaked it for the akg when isent it to him. 

 I have a bare pair of ad8067 - they are sot23-5 so you need a custom adapter from wilmslow adaptics. About a fiver each. I dont have any spare ones. 

 I look forward to hearing about ad843 and ad8065 without the caps - the ad8067 is sure to be better even than that!_

 

Hi Nick,

 NO, you _don't_ have the 10M and 100K trimpots fitted but if you send your amp to me I'll fit them FOC for you.... you really "must" listen to the LM6171 / LM6181 without output caps and the only way you can do that is with the trimpots fitted so you can zero the offset..... even with the other opamps you're trying it's best to have the trimpots in place in order that you can adjust the offset to 0.00mV on both channels.

 Basically you trim the offset by turning the screws on the trimpots and check between sleeve and ring and sleeve and tip using a Multimeter set to the 200mV (DC) range...... It's easy to do and I recommend you get this done so you can trim the DC offset to 0.00mV.

 Here's what the trimpots look like..... if you have them in your amp you'll notice them:





 Trimpots are the blue things with R & L written on them (denotes each channel)

 Mike.


----------



## 12796

Thanks! I have to send the amp back to wna to get the ad8067 and Bg vishay fitted so I had planned to sort the trim pots at the same time. Where is the 10M resistor? i will take a look. Did you find any issue with the ad8065 stabilty or any tips for tweaking it?


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Thanks! I have to send the amp back to wna to get the ad8067 and Bg vishay fitted so I had planned to sort the trim pots at the same time. Where is the 10M resistor? i will take a look. Did you find any issue with the ad8065 stabilty or any tips for tweaking it?_

 


 10M is in series with the wiper of the trimpot thus:






 You won't have the 10M on your amp Nick. Only if you remove the output caps and use the Lm6171 is it really necessary to fit the 10M & 100K trimpot though it's also handy for reducing the offset with some other opamps.

 Didn't find any stability issues with the 8065 but I was using output caps..... will try the 8065 without the output caps and let you know.


----------



## FritzS

Has anyone tested other output transistors in place of BD138/139?
 Toshiba's 2SC2238 / 2SA968 have a higher ft - about 100 MHz


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Here's what the trimpots look like..... if you have them in your amp you'll notice them:




 Trimpots are the blue things with R & L written on them (denotes each channel)
 Mike._

 

What case use you? I search for a little bit greater - for place for a headphone protection circuit kit.


----------



## 12796

Did you try loading resistors or comp caps in the f/b loop at all? cap drive seems to be important for the treble and bass.


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Has anyone tested other output transistors in place of BD138/139?
 Toshiba's 2SC2238 / 2SA968 have a higher ft - about 100 MHz_

 

Hi Fritz,

 The transistors are BD139 / 140 I haven't tried the tosh varieties but maybe someone else here has? I tend to stick with the stock kit parts and only really experiment with alternative opamps and caps etc. Have you got your kit as yet Fritz?

  Quote:


  Originally Posted by *FritzS* 
_What case use you? I search for a little bit greater - for place for a headphone protection circuit kit._

 

The enclosure I use is the bog standard Hammond 1455N1602 which measures 160 x 103 x 43mm Part number N77AL available from Maplins You will certainly need a slightly larger enclosure if you're contemplating incorporating a headphone protection circuit... then again, you may have enough room in a 1455N1602 to piggyback the head protection circuit onto the amp PCB dependant on the size of the protection circuit etc.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Did you try loading resistors or comp caps in the f/b loop at all? cap drive seems to be important for the treble and bass._

 

I must confess I didn't Nick..... plug and played it and all sounded fine with OP caps in place.. will try without OP caps and report back.

 As I type this AD744 is in the circuit (brand new virgin) and sounding exceptionally good, very spacious with superb three dimensional soundstage but the mids are ever so _slightly_ recessed (laid back) with the treble and bass dominating the proceedings..... even so, this is one pretty nice sounding opamp and I am taking notes 
	

	
	
		
		

		
			





 truckloads of space around instruments though.... a very thrilling, roller coaster ride of a listen indeed..... will let it burn in for a few hours. Dunno why I haven't rolled this puppy in before now


----------



## 12796

I havent tried that one yet - I have heard good things about it though.

 Did you try ad847 yet? Try that one without caps too. 

 I will send you two ad8067 - PM me your address. 

 I am still interested in the composite pcbs - I sugggest ad8067 coupled with ad847 will be stellar. 

 I suggest we try out a few more opamps (ad843-847-8065-8067 et al). Then concentrate on tweaking the best one as we did with the lm6171. I bet some of these chips have a lot more to give to given the spec sheet notes.


----------



## PinkFloyd

To be honest Nick..... this 744 is a lot better than the 843, just did a _*very quick*_ hot swap and the 843 sounds thin and veiled compared to the 744 which is now in again.... must get David to have a listen to this one.

 PS: my new opamp "puller" is superb I can remove and refit 2 opamps in 12 seconds flat now 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## 12796

Where did you get the puller?

 I would remove the caps before reaching a final judgement


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Where did you get the puller?_

 

It's actually the trim remover for my cars alloy wheels (to gain access to the nuts) It's a perfect fit and slots under the opamp.... you then simply lift up and out she pops 
	

	
	
		
		

		
		
	


	





























  Quote:


  Originally Posted by *biovizier* 
_I would remove the caps before reaching a final judgement _

 

To be honest Nick..... removing the output caps is the same as going from an opa134 to a LM6171... they stifle the sound something horrible, I would NEVER go back to using output caps....... NEVER.... they are like putting a mattress between your ears and the signal..... awful!


----------



## 12796

I have removed the input caps too. No caps at all now! Works with the ad8065 a treat.


----------



## PinkFloyd

Nick,

 There is a chip I'm trying at the moment and I'm not going to tell you what it is until next week (I'll give it a good listen all weekend) I _can_ say that it is seriously "by far" streets ahead of all of the others I have tried and it gives new meaning to the term "spaciousness".

 Sounds are coming from all directions..... directions I didn't even know existed! No Bull, to my ears the search is well and truly over (for me) Nick..... as I say, I'll give it a damned good listen over the weekend and if things remain the same or get better I'll divulge on Monday.... I want to be absolutely certain about this before saying any more........

 Mike.


----------



## 12796

you little tease! lets see how it stacks up against the ad8067 without any caps.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_you little tease! lets see how it stacks up against the ad8067 without any caps._

 

Let's just say I find it so good that I'm off out to increase the gain a tad right now! A clue for you, It's not an AD chip and neither is it considered a "high end" chip


----------



## StevieDvd

Is it one of the NE/SA/SE5534 per chance?

 Give me more soundstage pleeeeeeeeeeeaaaaaaaaaaaasssssse 
	

	
	
		
		

		
		
	


	




 Will I need to learn how to trim my WNA to opamp swap soon


----------



## 12796

Yeah the ne5534 I bet. Or an lt1028.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Yeah the ne5534 I bet. Or an lt1028._

 

Not even warm 
	

	
	
		
		

		
		
	


	




 not NE or LT you'll probably piss yourself laughing when I tell you what it is and call me the antichrist which is why I wanna be "*absolutely*" sure that what I'm hearing isn't a freak of nature / hallucination or an otex overdose before I say what it is!

  Quote:


  Originally Posted by *StevieDvd* 
_Will I need to learn how to trim my WNA to opamp swap soon 
	

	
	
		
		

		
		
	


	


_

 

No. all you have to do is pee about with the trimpots Steve until the offset is zero on both channels (with a screwdriver) piece of cake..... in fact, with this particular opamp you don't need trimpots, input caps or output caps 
	

	
	
		
		

		
		
	


	




 Edit: your amp is output cap free with trimpots isn't it Steve?


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Not even warm 
	

	
	
		
		

		
		
	


	




 not NE or LT you'll probably piss yourself laughing when I tell you what it is and call me the antichrist which is why I wanna be "*absolutely*" sure that what I'm hearing isn't a freak of nature / hallucination or an otex overdose before I say what it is!_

 

It's not a 3amp fuse is it? 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *PinkFloyd* 
_No. all you have to do is pee about with the trimpots Steve until the offset is zero on both channels (with a screwdriver) piece of cake..... in fact, with this particular opamp you don't need trimpots, input caps or output caps 
	

	
	
		
		

		
		
	


	


_

 

Where do you measure it though?

  Quote:


  Originally Posted by *PinkFloyd* 
_Edit: your amp is output cap free with trimpots isn't it Steve?_

 

Yep, that's the one.


----------



## 12796

Maybe it sounds so good BECAUSE you have removed both sets of caps? Try the ad8065 in the same configuration


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_It's not a 3amp fuse is it? 
	

	
	
		
		

		
			



_

 

No, It's a chrome plated safety pin 
	

	
	
		
		

		
		
	


	




 <joke>


  Quote:


  Originally Posted by *StevieDvd* 
_Where do you measure it though?_

 

First you arm yourself with a multimeter set to the 200mV range (200m DC)

 Once suitably armed with said multimeter you probe between sleeve and ring (right channel) and sleeve and tip (left channel)..... just back from taking a couple of pics hope this makes it easier to follow:





 Multimeter set on 200m setting (DC)





 With amp turned on but no music playing probe between sleeve and ring (ground and right channel) as shown. The offset (if any) will be displayed on your multimeter. If there is DC then trim the right channel pot (using the screw on the pot) until it measures as close to 0.00mV as possible. It may take quite a lot of turns of the screw but you'll get it down to 0.00mV eventually. 





 Again.... With amp turned on but no music playing probe between sleeve and TIP (ground and left channel) as shown. The offset (if any) will be displayed on your multimeter. If there is DC then trim the left channel pot (using the screw on the pot) until it measures as close to 0.00mV as possible. It may take quite a lot of turns of the screw but you'll get it down to 0.00mV eventually. 

 IIRC I marked your two trimpots L & R Steve? so, you adjust the *L* trimpot to trim the left channel (whilst probing between sleeve and tip to measure the DC) and you adjust the *R* trimpot to trim the right channel (whilst probing between sleeve and ring to measure the DC)

 I hope this makes sense, I'm not long out of bed and have a blistering headache but will add more to this tutorial later on if necessary.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Maybe it sounds so good BECAUSE you have removed both sets of caps? Try the ad8065 in the same configuration _

 

Been there done that last year but will go there again once I *mount* my 8065's Nick..... tried them in the MKl and really loved them but then, after prolonged listening, I (for some reason) deleted my 8065 rave post and wrote this:

 [size=large]11-01-2004[/size]

 [size=medium]"Further to my ravings on the AD-8065 I fear I was premature in extolling their sonic virtues. Prolonged listening to a wide variety of musical genres (lasting to 5am this morning ) revealed some kinks in the 8065's armoury which has made me decide to go back down the LM6171 route.......

 With simple music such as a Jazz trio, electro, reggae etc. the AD8610 has no problems handling things and sounds pretty darned good..... it's only when you play a more complex piece of music that it falls by the wayside bigtime .......

 Tchaikovsky's 1812 overture is a prime example, the opening sounding mellifluous and melodic just as it should do... so good so far... however, near the end of the piece things go seriously out of control big time.... instead of the usual climactic assortment of bangs and crashes, canons firing and pealing of bells my ears were presented with a mismash of congested rasping and clashing sounds..... I just couldn't make out any of the individual instruments it was a right old cacophony! seriously ear bleedingly harsh, splashy and trashy sounding.

 Ad-8065 is the same across the board with any complex piece of music it just runs out of steam and instruments all run into each other and come across as one congealed, compressed mass instead of individual instruments each doing their own thing in their own space in the soundstage.

 Pity as the AD-8065 sounds so good with very simple music 

 Oh well, it's back to the LM6171 for me and I've ordered some 470uF ALCAP output caps which should cover all bases and eventualities.. the 12uF I had been using were obviously not high enough capacitance so I can't wait to hear the WNA with LM6171 and 470uF ALCAPS 

 Will report back on the large ALCAP and LM6171 combo"[/size]  

 Things have certainly "*progressed*" since then (470uF ALCAPS "Cringe") Must try them again in the MKll, they really were a nice sounding chip in the MKl.

 EDIT: The amp I tried the 8065's in was a bit of a disaster zone / Rice Krispie (snap crackle & pop) if truth be told so yeh, will definitely give them another whirl in in the "tidy" MKll 
	

	
	
		
		

		
		
	


	




 Disaster Zone:


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_No, It's a chrome plated safety pin 
	

	
	
		
		

		
		
	


	




 <joke>

 First you arm yourself with a multimeter set to the 200mV range (200m DC)

 Once suitably armed with said multimeter you probe between sleeve and ring (right channel) and sleeve and tip (left channel)..... just back from taking a couple of pics hope this makes it easier to follow:
 ...
 I hope this makes sense, I'm not long out of bed and have a blistering headache but will add more to this tutorial later on if necessary.

 Mike._

 

Thanks that makes perfect sense, now I know what to do when I find out what you are using instead of the safety pin.

 Steve


----------



## Henry Morgan

Is it time yet for Pinky to reveal the new champion device? I've not been up to speed lately with my WMA headphone amp due to other distractions, so I've got a lot of catching up to do. Long winter months ahead now etc.
 Henry.


----------



## Alick

Quote:


  Originally Posted by *Hernry Morgan* 
_I've not been up to speed lately with my WMA headphone amp due to other distractions, so I've got a lot of catching up to do. Long winter months ahead now etc._

 

Me too Henry. I can't quite believe how long I've been away from this thread. However, summer has gone and, although I've been listening a lot (I replaced my Squeezebox with a Squeezebox2 and did away with my external DAC), it's time to lift the lid and do some modding again. I never did get round to doing the trimpot mod, so that's next.

 Mike, ISTR that you reverted to the original bias current when you removed the output cap's. I'd like to do the same as introducing heatsinks has made things look like a dogs dinner as there really isn't the room for them given the spacing of the transistors on the board. Did you find that the increased bias current mod was less effective with the cap's out?

 BTW, I see David has updated the catalogue and the Mk2 is now listed (at least I assume it's the Mk2).


----------



## 12796

so what is the chip pinkie?


----------



## StevieDvd

Yes will mine need to be upgraded to the new superchip?

 Steve


----------



## raja

Hi,

 I remember there was interest in the super regulators at one point.

 Here is a link for a possible upcoming purchase of pcb's,

 The pcb's are very cheap, but parts can still cost around £20 or so, for this cost you should be able to stuff a couple of boards.

 How the super reg's will work on the updated headamp is a bit of a mystery though, as the power supply is improved over the previous versions.

http://www.pinkfishmedia.net/forum/s...ad.php?t=15588



 thanks
 Raja


----------



## 12796

Unfortunately I am banned from pink fish


----------



## Jazper

what's the bet it's a TL071?


----------



## raja

Quote:


  Originally Posted by *biovizier* 
_Unfortunately I am banned from pink fish _

 


 tut tut sonny, what've you been up to?



 The thought of the opamp being the tl071 had crossed my mind too.


 Thanks
 Raja


----------



## 12796

its a 741!

 I had the temerity to suggest naim were poor VFM, linn make awful turntables and ATC can strip the paint off walls. Then I got abused by kiddies every time I posted - including the mods. Gave them a sound thrashing and got banned eventually. Mods then deleted all requests for my return.

 Nick.


----------



## PinkFloyd

Jeez Geezers, it's not a "superchip" or some mysterious wonderchip It's the good old Burr Brown OPA228P.

 I've got it running in both my amp _and_ Steviedvd's MKl amp at the moment with no output caps, no input caps or other **** in the signal path..... It's by far "my" favourite in the WNA but that doesn't necessarily mean a lot as ears are as unique as fingerprints and we all hear things differently... some may love it, some may like it and others may despise it but It sure is worth giving it a try.

 To be perfectly honest I'm sick and tired of that prima donna LM6171 and all the associated crap that's required to get it to work without oscillating or behaving badly.... output caps, input caps, trimpots etc.

 I'm going back to bare bones where less is more and the OPA228P suits _my_ ears down to the ground. I haven't posted before now because I wanted to be absolutely sure..... at the moment It's pretty much plug and play (without input / output caps) with zero DC offset (+0.01mV R 0.00mV L) and I'm sure even more could be squeezed out of it...... It likes a gain greater than "5" so It's probably a good idea to "up" the WNA's gain to 6 though it works perfectly well with the standard WNA gain of 4.3

 Listening to Steviedvd's "Barebones" 228 MKl WNA right now (after spending the afternoon and evening faffing about with it) and Frank Sinatra sounds like he's in the same room with me (dunno if that's good or bad!) I'll leave you to comment on it Steve and if it doesn't suit your ears then I'll retrofit the LM6171, input caps, trimpots, 10M resistors et al.

 You can also try the AD8065, OPA627 and many more chips Steve without the need for the signal strangling in / out caps.... They are direct drop in (plug and play) chips, try them all!

 Mike.

 Zippin' up my boots, goin' back to my roots, yeah,
 To the place of my birth, back down to earth.

 I've been standing in the rain,
 Drenched and soaked with pain,
 Tired of short time benefits
 And being exposed to the elements.
 I'm homeward bound, got my head turned around.

 Zippin' up my boots, goin' back to my roots, yeah,
 To the place of my birth, back down to earth.
 Ain't talkin' 'bout no roots in the land,
 Talkin' 'bout no roots in the man.
 I feel my spirit gettin' old, it's time to recharge my soul.
 I'm zippin' up my boots, goin' back to my roots, yeah,
 To the place of my birth, back down to earth.

 Zippin' up my boots, goin' back to my roots.
 To the place of my birth, back down to earth.


----------



## raja

Quote:


  Originally Posted by *biovizier* 
_its a 741!

 I had the temerity to suggest naim were poor VFM, linn make awful turntables and ATC can strip the paint off walls. Then I got abused by kiddies every time I posted - including the mods. Gave them a sound thrashing and got banned eventually. Mods then deleted all requests for my return.

 Nick._

 


 Oh well, I guess you live 'n' learn bro'.

 I agree with pinkie, sometimes less is more. Sometimes when you complictae the signal path as little as possible it sounds best.


----------



## StevieDvd

PinkFloyd said:
			
		

> Jeez Geezers, it's not a "superchip" or some mysterious wonderchip It's the good old Burr Brown OPA228P.
> [/QUOTE=PinkFloyd]
> 
> Superchip, we're pulling your leg Mike we were just eager to find out the mystery chip.
> ...


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_its a 741!

 I had the temerity to suggest naim were poor VFM, linn make awful turntables and ATC can strip the paint off walls. Then I got abused by kiddies every time I posted - including the mods. Gave them a sound thrashing and got banned eventually. Mods then deleted all requests for my return.

 Nick._

 


 Sounds to me like you hit the nail right on the head (or naim on the head) with with some of your comments. *Some* of those guys at PF are so far up their own arseholes that its impossible to voice a different opinion without being classed as an antichrist. At pink fish you're nobody unless you have a NAIM, probably one of the main reasons I use Head-Fi instead of their illiberal forum, at least you can voice your opinion here (on all things audio) without being tarred and feathered, birched or banned..... 

 This is totally off the WNA topic so I'll say no more but I'm sorry they treated you that way Nick, so much so that I won't be visiting PF anymore (no great loss to them as I think NAIM is a crock when it comes down to VFM too!)

 Anways, back over to the WNA thread.....................


----------



## 12796

thanks pinkie! yes I think a few people there have "purchase insecurity". One guy spent £9k on putting ELEVEN (!!!) mana platforms underneath his atc 100a's. He claimed it made the bass cleaner - nothing to do with the fact the bass driver was now 5 feet from the floor! 

 I am curious to see what you think of the ad8065 "nude" without caps. Does the opa228 share the burr brown house sound?


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I am curious to see what you think of the ad8065 "nude" without caps._

 

I'm just off out to totally strip _my_ MKll down to bare bones (remove trimpots / inputs caps etc.) and I'll sure give the 8065 another spin under the bonnet once I mount them on Bdogs, my last pair of mounted 8065's are long gone. 8065 sounded superb "with" in / out caps so I'd imagine they'll sound a heck of a lot better without...... will keep you up to speed for sure Nick I hope they suit my ears.

  Quote:


  Originally Posted by *biovizier* 
_Does the opa228 share the burr brown house sound?_

 

Funnily enough..... yes _and_ no. I'd describe it as more of a hybrid AD / BB type of sound but you'd have to evaluate it yourself in order that _it_ can describe itself your own original set of acoustic devices (_your_ ears!)

 It's a well known fact that no two sets of ears are the same, they are literally as individual and unique as fingerprints, so we all hear sounds slightly differently..... what I hear as mellow you may hear as harsh, so on and so forth. Much the same way as different rooms / furniture affect the acoustics so do different shapes of ears... ears are an "acoustic device" and if we all had the same shape of ear we would hear things the same but we don't which is why there are so many differing opinions on audio equipment.

 There's no way I can say "XYZ sounds incredible go and listen to it you'll be amazed" I learnt that many years ago after reading rave reviews only to think "that guy must be deaf as a post" or "the company are giving him backhanders" after hearing the _rave review _ gear with my own ears.......

 By all means listen to the 228 Nick and if you like it then, great. Whatever you do, don't go with the "herd" and follow them over the edge of the cliff.... use your ears and go with what sounds best to you..... just because a chip is popular with the herd (ie: OPA627 is the best chip since sliced bread) doesn't mean a thing... FOTM, following people like sheep and conforming to the "group perception" of what's good has never been my approach.. I love the sound of the old NE5534 in certain applications and would probably branded a "nutter" or "behind the times" by certain "groups"..... who gives a damn, if it sounds good it "is" good.

 So..... UYOE (use your own ears) and form your own conclusions and to hell with what the "group" thinks.

 From here on in all I'll contribute to this thread is what chips work in the WNA and how you can optimise them.... that was basically what this thread was all about from the start "constructing the amp and tweaking it".........

 Edit: Bad week, bad mood.... so much for "abstaining" doing you the world of good


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_
 If as you mentioned before it's more spacious then it's likely to float my boat._

 

Look forward to your impressions captain.


  Quote:


  Originally Posted by *StevieDvd* 
_BTW what was the problem with my WNA was it a blown component?_

 

As discussed, *cause* unknown and nothing had failed..... pity I replaced nearly every component on the board _before_ snipping the pot to ground wire as that rectified the "problem" instantly.... probably my fault for grounding the pot to the 0V track in the rail splitter section but the fact it worked fine for weeks and then went pear shaped all of a sudden has both myself and Dr. White scratching heads.... whatever it was, a simple "snip" was all that was required in the end.

 What PSU do you use with it Steve? I was listening with one of those powerPak 24V switchers and then went over to my Calex PSU and what a difference! The MKl certainly does benefit from a beefier / quality PSU that's for sure, try and power her with something good if you can. I'm used to the calex and tried the little switcher with the MKll and "ouch"..... not nice, not nice at all 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *StevieDvd* 
_I'll send a cheque to cover postage and parts etc but we can deal with that via PM._

 

You'll do nothing of the kind Steve. I put the amp together and, as I say, my grounding the pot to 0V in the rail splitter probably had something to do with the amp going all queer so I'll take the blame..... I actually (in a sadistic kind of way) enjoyed tearing what's left of my hair out yesterday (at one point I was wielding a hammer and actually smashed the **** out of an LM6171 
	

	
	
		
		

		
		
	


	




 ) It was a good learning curve for me and also proved that I can work calmly under pressure. It also gave me the opportunity to test drive my new reading glasses (never worn glasses before) so I could actually see what I was doing 
	

	
	
		
		

		
		
	


	




 She'll be back with you shortly, so get ready to hoist your anchor!

 Mike.

 PS: Still haven't got round to removing the trimpots and input caps from my WNA but they will be out ASAP..... if your amp is anything to go by "barebones" sure is the way to go.... Just be sure to power her with something pretty decent, that little 24V / 550mA PowerPak switcher jobby is pretty dire compared even to the basic stontronics regulated wallwart which is not half bad (IIRC you have the stontronics regulated wallwart?) I used to think the PSU didn't make "that" much of a difference but in the MKl it certainly does without a doubt. These puppies  are _*[size=medium]superb[/size]*_ with the WNA, they require housing but it's well worth the effort. I use the 32024A and It's probably the best purchase I've made PSU wise........ bullet proof / stable as a rock and Made in England.





 32024A housed in a blue Hammond


----------



## StevieDvd

You recall correctly, I do have the Stontronics wallwart around which I'll use over the switcher though I did not think it made a difference with the early WNA config. Perhaps the back to basics WNA does make the difference more noticeable.

 Is it just me or are most people scared of making their first mains project. 240v over a 9v pp3 needs a little more care, though I've heard the pp3 can give you a nasty tongue burn 
	

	
	
		
		

		
		
	


	




 If the Calex is that easy to build I suppose I can give it a go, I'll just make sure the house insurance is up-to-date first.

 Did you get the Calex direct from them or via someone like Rapid?

 I'll make sure my boat is fitted with circuit breakers 
	

	
	
		
		

		
		
	


	




 Steve


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_You recall correctly, I do have the Stontronics wallwart around which I'll use over the switcher though I did not think it made a difference with the early WNA config. Perhaps the back to basics WNA does make the difference more noticeable.

 Is it just me or are most people scared of making their first mains project. 240v over a 9v pp3 needs a little more care, though I've heard the pp3 can give you a nasty tongue burn 
	

	
	
		
		

		
		
	


	




 If the Calex is that easy to build I suppose I can give it a go, I'll just make sure the house insurance is up-to-date first.

 Did you get the Calex direct from them or via someone like Rapid?

 I'll make sure my boat is fitted with circuit breakers 
	

	
	
		
		

		
		
	


	




 Steve_

 

Rapid used to stock them but no longer do, you can give calex a ring and they'll probably sell you one.... there's nothing to do apart from hardwire the 240V supply to the transformer (piece of cake) and the installation info sheet is a breeze to follow..... overload protection etc. is part and parcel of the PSU.... mine has been on 24/7 for over a year..... just have a look at the spec sheet, it's a good unit. More on it tomorrow, I'm knackered 
	

	
	
		
		

		
		
	


	




 I'll give you a loan of mine and see what you think Steve..... you'll see / hear what I mean.

 Night.

 Mike.


----------



## PinkFloyd

Get your HD-650's ready Steve, I'll probably manage to get the amp over to you via next day SD tomorrow.

 I replaced the slightly thin L/H Phono socket with another one so your interconnect will now have a bit more grip on it.

 Changed the headout socket, dimmed the LED (5K1), new transistors, removed all caps from the signal path, removed trimpots, AD744 now in rail splitter, OPA228 now in amp, 0.00mV DC on both channels, buffed up the aluminium fascia etc. etc.

 Have a listen and let me know what you think of the 228 / 744 (be brutally honest) If you've got a spare 627 kicking about then try it in the rail splitter in place of the 744 (I prefer the 744 but the 627 adds a touch of warmth which you may / may not like) you can even try your 627's, 8065's etc. in the amp section (plug and play) but I'm interested in your opinions of the MKl with the 228's in situ.... feedback in this thread or in the MKl thread, whatever suits you best 
	

	
	
		
		

		
		
	


	




 Try her out with your best PSU, if you still have the mascot it will be fine with the 228's / 744 
	

	
	
		
		

		
		
	


	




 A couple of snaps of your cap free MKl:





 Barebones 
	

	
	
		
		

		
		
	


	








 Without lid on and screws not tightened / aligned 

 Mike.


----------



## 12796

http://www.sgheadphones.net/index.ph...er&f=12&t=2628


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Get your HD-650's ready Steve, I'll probably manage to get the amp over to you via next day SD tomorrow.

 ...

 Have a listen and let me know what you think of the 228 / 744 (be brutally honest) If you've got a spare 627 kicking about then try it in the rail splitter in place of the 744 (I prefer the 744 but the 627 adds a touch of warmth which you may / may not like) you can even try your 627's, 8065's etc. in the amp section (plug and play) but I'm interested in your opinions of the MKl with the 228's in situ.... feedback in this thread or in the MKl thread, whatever suits you best 
	

	
	
		
		

		
		
	


	




 Try her out with your best PSU, if you still have the mascot it will be fine with the 228's / 744 
	

	
	
		
		

		
		
	


	



 ...

 Mike._

 

I'll keep it brief to avoid hijacking the thread.

 I've emailed Calex re the psu parts (no reply yet) so will use the large Stontronics wallwart (Monarch psu was sold with an amp). I'll build a Calex based one unless it's almost as cheap to buy a good one, (Solo psu @ £150!).

 I've got three 627s so I can change the rail splitter and tryout some opamp combinations. Now I'll be able to assess a pair of opamps in both my WNA and SM3 and try to nail down my personal preferences.

 The clean up looks good and I can't wait to put the WNA back into it's vacant slot.

 But of course the most important thing is a big Thank You for getting the WNA back in operation for me.

 Regards Steve

 PS YGPM


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_http://www.sgheadphones.net/index.ph...er&f=12&t=2628_

 







 It's all subjective (have a GOOD read of this), suck it and see and if it suits your ears it is good... there is no _one_ opamp or musical device that will be right for _everyone_ Nick..... There's an opamp / musical device to _suit_ everyone, it's finding the right one for _you_ that is the hard part of the journey.... not many people are willing to open their minds and experiment and some peoples opinions are cast in stone and they will never budge..... for them to accept new ideas means feeding their sub conscience with positive self talk etc. etc. there's a lot of psychology involved in all of this, believe me. 

 You'll NEVER get agreement across the board and no one opamp will be a panacea / cure all that will satisfy everybody there will always be debate and there's a lot more factors involved than just simply listening..... if you believe and tell yourself that XYZ opamp sounds best you have fed your sub-conscience with this belief and it makes sure you act on that belief (that's its job) anything contradictory to the information (self talk) you have fed your sub conscience creates panic / uncertainty / disbelief and argument...... ie: you lose your wallet, for example, and you say "I've lost my wallet" even though your wallet may be right in front of you you won't see it as your subconscience has been instructed that "I have lost my wallet" and it creates a scotoma so you won't find it because if you were to find it that would make you feel stupid as the last thing your sub conscience wants you to do is find it. When your wife says "there it is, right in front of you" your reaction is "who the hell put it there, it wasn't there a minute ago........ it "was" there all the time but your SC made sure you didn't notice it as you already instructed it with your self talk that you have lost it.


 I could really go in to depth but to do so would take a long long long time and I'm so tired at the moment that I am almost hallucinating..... Try and read some of Lou Tice's  articles on scotomas, self talk, flip back flip up, negative wizards etc. etc. It's superb stuff and puts everything in your life into perspective............ I've probably just waffled a load of meaningless drivel which is why I suggest you try and get hold of some of Lou's work. Whether it be audio, buying a new car, getting married, getting a new job Lou really opens your mind and he can help change your self talk, understand why we behave the way we do and you can apply it to any situation.

 With regard to opamps my self talk is "every opamp in the world is good and one of them will suit a certain individuals requirements perfectly" If I were to hold any other belief then I couldn't possibly remain impartial and open minded to all opamps.


----------



## StevieDvd

The WNA had returned from its trip to Scotland after some TLC from Mike (Pinkfloyd) and had been fitted with an AD744 rail splitter and 2 OPA228 for L/R channels.

 Having recently bought the Black-eyed Peas CD Monkey Business I tried that first as it was fresh in my mind, they certainly like the bass deep but it really got the old toes tapping.

 Next CD was Master & Commander soundtrack as there are some incredible instrumental tracks with violin and cello that just seem to be so intense.

 I tried a few other favourite tracks but I was finding the listening was getting a little fatiguing which was kind of odd as I'd not really experienced that on the WNA before. The bass was certainly present as the Black-eyed Peas illustrated and the detail on the Master & Commander tracks was also still present.

 As Mike had suggested I put an OPA627 in the rail splitter but much of the same to report with that in place. Everthing was there but something was wrong, I hoped it was not just me.

 I have some spare opamps from my Supermacro so I decided what the heck fit the same ones I have in that as a starter. The SM3 has SE5534 OBCA (opamps from On-Semi, the OBCA means they were put in class A using a resistor between 2 pins and using the bypass of pin 5 to pin 6). The best 5534 I had other than the ones fitted to the SM3 are the On-Semi SA5534, so fitted these and powered up the WNA.

 Well what can I say; these are my opamps of choice. The soundstage was very evidently improved and the spacing around the instruments seemed clearer and more distinct. I think the fatigue with the 228s was my poor brain trying to 'respace' the music to its expectations and the SA5534 supplies just what my ears/brain expects.

 I think the synergy is my brain and these 5534s. Sitting in the drawer are pairs of AD843, AD847, OP627, AD797, OPA604 & LT1115 and now the OPA228s I'm afraid.

 Sorry Mike 228s are not for me

 I think the opamp rolling is finished for a while as I've found my niche and I like it. Perhaps flavours of 5534 vary but to me the SM3 sound and now WNA sound are just about right.

 Odd I may be but also content. I've got a Ray Samuels Hornet and a pair of Grado HF1 to come but next expenditure is on CD's.

 I know some people can give better impressions of what they hear but I just listen to the music and don't over analyse it. It's basically better or worse when I opamp roll and I’ll try to stick now on the better.

 Blimey a long post from me!

 Steve


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_The WNA had returned from its trip to Scotland after some TLC from Mike (Pinkfloyd) and had been fitted with an AD744 rail splitter and 2 OPA228 for L/R channels.

 Having recently bought the Black-eyed Peas CD Monkey Business I tried that first as it was fresh in my mind, they certainly like the bass deep but it really got the old toes tapping.

 Next CD was Master & Commander soundtrack as there are some incredible instrumental tracks with violin and cello that just seem to be so intense.

 I tried a few other favourite tracks but I was finding the listening was getting a little fatiguing which was kind of odd as I'd not really experienced that on the WNA before. The bass was certainly present as the Black-eyed Peas illustrated and the detail on the Master & Commander tracks was also still present.

 As Mike had suggested I put an OPA627 in the rail splitter but much of the same to report with that in place. Everthing was there but something was wrong, I hoped it was not just me.

 I have some spare opamps from my Supermacro so I decided what the heck fit the same ones I have in that as a starter. The SM3 has SE5534 OBCA (opamps from On-Semi, the OBCA means they were put in class A using a resistor between 2 pins and using the bypass of pin 5 to pin 6). The best 5534 I had other than the ones fitted to the SM3 are the On-Semi SA5534, so fitted these and powered up the WNA.

 Well what can I say; these are my opamps of choice. The soundstage was very evidently improved and the spacing around the instruments seemed clearer and more distinct. I think the fatigue with the 228s was my poor brain trying to 'respace' the music to its expectations and the SA5534 supplies just what my ears/brain expects.

 I think the synergy is my brain and these 5534s. Sitting in the drawer are pairs of AD843, AD847, OP627, AD797, OPA604 & LT1115 and now the OPA228s I'm afraid.

 Sorry Mike 228s are not for me

 I think the opamp rolling is finished for a while as I've found my niche and I like it. Perhaps flavours of 5534 vary but to me the SM3 sound and now WNA sound are just about right.

 Odd I may be but also content. I've got a Ray Samuels Hornet and a pair of Grado HF1 to come but next expenditure is on CD's.

 I know some people can give better impressions of what they hear but I just listen to the music and don't over analyse it. It's basically better or worse when I opamp roll and I’ll try to stick now on the better.

 Blimey a long post from me!

 Steve_

 

And a very honest and well written post Steve, I'm glad you spotted the lemon...... you know what I mean 
	

	
	
		
		

		
		
	


	




 Just check the offset of the 5534 not only at zero volco level but also at all volco levels...... I listened to it today and, yes, superb sounding. Without input / output caps you'll find that the likes of the AD 847 will measure say 0.7mV at zero volco setting but more like 170mV at max setting.... this is "not" good and all will be explained tomorrow once I've had a good sleep.....

 The good old 5534 is a cracker though and many manufacturers are frightened to use it, even though it sounds excellent, for fear of being classed as behind the times even though the majority of the equipment used in the recording studios uses the 5532 / 5534....... more on this tomorrow as well.

 Mike.


----------



## 12796

Stevie - what do you think of the ad843 and ad847 in comparison?


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Stevie - what do you think of the ad843 and ad847 in comparison?_

 

Did you not read Nick? if you put the AD-847 in a capless WNA the DC offset will rise sharply when you turn the volco up.... if you want 100mV or more going into your headphones then fitting an AD-847 without in / out caps is an easy way to achieve it.


----------



## FritzS

Quote:


  Originally Posted by *StevieDvd* 
_I have some spare opamps from my Supermacro so I decided what the heck fit the same ones I have in that as a starter. The SM3 has SE5534 OBCA (opamps from On-Semi, the OBCA means they were put in class A using a resistor between 2 pins and using the bypass of pin 5 to pin 6). The best 5534 I had other than the ones fitted to the SM3 are the On-Semi SA5534, so fitted these and powered up the WNA.
 Well what can I say; these are my opamps of choice. The soundstage was very evidently improved and the spacing around the instruments seemed clearer and more distinct. I think the fatigue with the 228s was my poor brain trying to 'respace' the music to its expectations and the SA5534 supplies just what my ears/brain expects.
 I think the synergy is my brain and these 5534s. Sitting in the drawer are pairs of AD843, AD847, OP627, AD797, OPA604 & LT1115 and now the OPA228s I'm afraid.
 Steve_

 

You will say - the old SA5534 sounds better than all others? But why upgrades some its older CD players or pre amps from SA5534/5532 to "more modern" OP's? I am confused!? 
	

	
	
		
		

		
			




 PS: Which manufacturers makes/offers 5534/5532 today?

 This I found too about ....
http://www4.head-fi.org/forums/showp...52&postcount=1
http://www4.head-fi.org/forums/showp...8&postcount=17
http://www.onsemi.com/


----------



## StevieDvd

Quote:


  Originally Posted by *FritzS* 
_You will say - the old SA5534 sounds better than all others? But why upgrades some its older CD players or pre amps from SA5534/5532 to "more modern" OP's? I am confused!? 
	

	
	
		
		

		
		
	


	



 PS: Which manufacturers makes/offers 5534/5532 today?

 This I found too about ....
http://www4.head-fi.org/forums/showp...52&postcount=1
http://www4.head-fi.org/forums/showp...8&postcount=17
http://www.onsemi.com/_

 

You've quoted the manufacturer I use (onsemi) and asked the big question!

 I think because the 5534 are cheap people think a newer more expensive opamp would naturally be better. It depends whether the manufacturers of broadcast equipment and CDs etc did actually fit the 5534/4432 for economy or some because the opamp was just right for that design. If there was a better amp that every manufacturer thought better the cost price would have fallen enough due to the volumes involved to make that a more standard default.

 Since the 5534 is still produced it must be filling a market.

 I can't say much about the technical details. I don't know why people use expensive opamps as rail splitters and cheaper one for the L/R channels. I have to rely on what I think suits me. If equipment was designed to suit my taste then a lot of people would probably complain about lack of bass or that the soundstage was too wide.

 Perhaps on the manufacturers test scales of taste I'm in the middle and that's where the 5534 sits as well.

 Steve


----------



## StevieDvd

Quote:


  Originally Posted by *biovizier* 
_Stevie - what do you think of the ad843 and ad847 in comparison?_

 

As mike has stated with the current setup of the WNA I have to be careful with the DC offset.

 However, in my portable SM3 I did try the 843/847 but I still prefer the 5534. We must have different preferences, the 843/747 are detailed but took a while to bed in but I missed the 5534 soundstage the most.

 I've got a small head and a cramped soundstage does not have much room to fit in, so I need an opamp which sounds to be outside the headphones to feel comfortable. 
	

	
	
		
		

		
		
	


	




 Steve


----------



## PinkFloyd

On the subject of the NE5534 / NE5532 I know an amplifier designer / manufacturer who reckons It's the best opamp since sliced bread and, by far, sounds the best in his amplifiers. The reason he doesn't "utilise" the NE5534 opamp in his designs? Because they wouldn't sell... he would be deemed behind the times by joe public and slated for being a neanderthal who doesn't know how to build an amp even though most of the broadcast equipment and studio gear uses the NE5534.... probably every recording you own has gone through an NE5534 / 32 at some point.

 It really amazes me some of this, people automatically (wrongly) assume that newer means "better" and the first thing they do when they buy a vintage CDP or amp that utilises an NE5534 / 32 is to replace it with something along the lines of an OPA627 just because Bill or Bob or Bert tells them that the 5534 is crap and is the first thing they need to change. I _had_ the same mentality myself years ago.... just read the opening paragraph of this (the Under the bonnet bit) and look how I "automatically" assumed the NE5532 to be nothing "particularly stunning" what a plonker I was.... I must have listened to Bob or was it Bert? hmmmm... maybe it was Bill who told me what I should be listening to? The darned amp never sounded as good after the 5532 was removed even though I tried to convince myself it did!!! We're all guilty of following the pack at some time or another 
	

	
	
		
		

		
		
	


	




 That reminds me, I must update that bloomin awful site 
	

	
	
		
		

		
		
	


	




 It's a sorry state when an amp manufacturer (who's been at the business end of recording studio gear and amp designs for over 30 years) should have choose _second best_ just to please the "knowalls" and to avoid public humiliation along the lines of "XYZ doesn't know what he's doing he uses an NE5534 in his amp, if I were him I'd have chosen an OPA627" etc. 

 Tragic.

More on the NE5534 / 32 here

 A brief excerpt and, as always, this is an individual opinion and not written in stone:

"In audio work, the 5532 is pre-eminent. It really is something like the ideal opamp. Distortion is almost unmeasurably low, even when driving 600 Ohm loads. Noise is extremely low; in many applications discrete devices give no significant advantage. (The exceptions being very high and very low source impedances) I have tried several times to make a discrete/opamp hybrid preamplifier, for a moving-magnet RIAA input, that would be quieter than the simple 5532 version. Each time I have failed. This may of course just mean that I am unusually incompetent at electronics, but I think the true reason is simply that the 5532 is very hard to beat. 
 The 5532 is not, however, perfect. The biggest drawback is the high bias and offset currents at the inputs. This is an inevitable result of using a bipolar input stage (for low noise) without any sort of bias-cancellation circuitry. (If this was added it would compromise common-mode noise, and probably also introduce common-mode distortion, according to my conversations with IC makers) The 5532 was designed for audio work, and makes few concessions to DC accuracy.Having said that, it's not actually that bad. The offset voltage spec is 0.5 mV typ, 4 mV max, compared with 3 mV typ, 6 mV max for the popular TL072. On many occasions I have used 5532s to replace TL072s when offset voltage was a problem. 

 If bipolar-style bias currents cannot be accommodated, then there are plenty of FET-input opamps around. However, there is no obviously superior device that is the equivalent of the 5532. The TL072 was used for many years but its HF linearity is not first-class and distortion across the band deteriorates badly as output loading increases."


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Stevie - what do you think of the ad843 and ad847 in comparison?_

 

Nick and Steve.

 Got a couple of SMD to Dip8 adaptors on the way from WNA and will be trying the 8065 again in the _naked_ amp. 

 I don't know if you tried your AD847 without output caps but, if you did, then [size=medium]be aware  [/size] that the DC offset will rise sharply as you turn the volume up and with low impedance 'phones this could be pretty nasty indeed. Same thing goes for the NE5534 (or any other non FET opamp) at minimum volco setting the offset will be low but as soon as you turn the volco up the DC will increase to unacceptable levels. Only use non FET opamps with output caps in position.

 FET opamps, such as the AD8065 and OPA 627 etc. can be used without input or output caps. As always, check the offset at "all volume levels" to ensure the offset remains the same across the range and doesn't rise.

AD 847  rose from 3mV at zero volco setting to about 140mV (totally bad!!!) at the 2 o' clock position so please be careful.

 Mike.


----------



## PinkFloyd

I came across this on Xin's site and It's "doable" with the WNA as long as you undo the opamp class A biasing mods in the WNA. Once the class A biasing mods have been undone you can plug and play the "7 legged" AD-744 and not have to worry about using in / out caps as the 744 is BiFET.... see how to do it here.

 To undo the opamp biasing in the WNA both of the constant current diodes in each amp channel should be 3.5mA and both of the associated resistors should be 120R. In other words replace the 5.6mA constant current diode in each channel with a 3.5mA type and the 75R resistor in each channel with a 120R type. Essentially what the AD744 mod does is bypass the AD744 class B output stage and feeds the output of the AD744 voltage amplifier stage directly into the WNA BD139/BD140 class A output stage. Once the WNA opamp biasing is undone (reversed) you plug and play your 7 legged 744 and "bingo!" away you go.

 Cheers to Xin for the 744 class A tweak and to Dr. White for the WNA opamp biasing reversal instructions.

 I haven't tried this yet but thought I'd share so anyone who's interested can give it a go.

 Mike.


----------



## StevieDvd

Mike,

 Xin calls this output bypassing (OB)and it can be done on a few opamps (NE/SA/SE5534, AD744 & AD829) not sure of any others. 

 His definition of class A adapting (CA) on the SM3 is a simple resistor between pin 6 & 7 of the opamp.

 It is also possible to combine the two OBCA using adapters he supplies. My SM3 is using SE5534 in both modes (OBCA).

 Whether that affects what you have stated above I can't say but it's worth noting that only a few opamps can use the bypass option.

 Steve


----------



## 12796

Quote:


  Originally Posted by *PinkFloyd* 
_Did you not read Nick? if you put the AD-847 in a capless WNA the DC offset will rise sharply when you turn the volco up.... if you want 100mV or more going into your headphones then fitting an AD-847 without in / out caps is an easy way to achieve it._

 

The akg 340s are 600 ohm remember 
	

	
	
		
		

		
		
	


	




 Look forward to your findings with the capless ad8065.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_Look forward to your findings with the capless ad8065._

 

Been up in the highlands all day and when I got back there was a "tried to deliver a package" card inside the door.....

  Quote:


  Originally Posted by *biovizier* 
_The akg 340s are 600 ohm remember 
	

	
	
		
		

		
		
	


	



_

 

What's that got to do with the DC offset?


----------



## 12796

Quote:


  Originally Posted by *PinkFloyd* 
_ the DC offset will rise sharply as you turn the volume up and with low impedance 'phones this could be pretty nasty indeed._

 

So its not as bad with high impedance phones right? I am using fet opamps currently so it should be fine.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_So its not as bad with high impedance phones right? I am using fet opamps currently so it should be fine._

 

FET's are _perfectly_ fine Nick and should measure almost zero DC. The 847 should not be used in a "nude" WNA..... just ask David and he'll explain the why and whens etc. They measure about 8mV @ minimum volco level but as soon as you increase the volume so increases the DC Offset and you honestly don't want a couple of hundred mV of DC going into your headphones.... next time you're on the phone to David get him to explain why this occurs, why you don't want it to occur and how to stop it from occuring (if you decide on the 847 that is)

 I should manage to pick up the soic to dip adaptors tomorrow from the post office so will solder the 8065's on when I've got a spare moment...... I'm running a nude WNA with 843's again (there's something about them that just "gels" and suits _my_ lug holes) but really look forward to trying the 8065's again but this time _without_ input and output caps


----------



## PinkFloyd

Managed to pick the WNA [size=medium]s8d[/size] kit up from the post office today and £4 for the kit isn't at all bad considering it comes complete with 2 x SOIC to Dip8 PCBS, a fair old length (2 feet) of wondersolder and gold plated pins.

 Even better is the fact the s8d adaptors pin outs come clearly marked so there will be no uncertainty when it comes to pin orientation. The gold plated pins have to be soldered to the PCB and don't rely on the usual "friction fit" of other adaptors I have tried so no oxidisation issues to worry about with the s8d..... good old fashioned soldered joints are the order of the day 
	

	
	
		
		

		
		
	


	




 Fit and finish is first class. I gave the pins a dry run and they slotted in beautifully, pity I didn't have time to solder the 8065's onto the s8d's today but will probably get around to it tomorrow evening.

 WNA reckon It's best to solder the SOIC opamp onto the board first and _then_ fit the gold pins.

 Now...... where did I put that magnifying glass? 
	

	
	
		
		

		
		
	


	








 WNA s8d Kit in Bag





 Contents revealed! 2 x SOIC to dip PCB's, wondersolder and gold pins





 Close up of s8d kit


----------



## PinkFloyd

Biovizier...... your ears / taste must be very similar to my own. Soldered the 8065's onto the WNA s8d adaptor earlier on and they are absolutely 100% to my ears. 

 I was (am!) _so_ impressed with their sound that I phoned David White and suggested he have a darned good listen to them.... they are "by far" streets ahead of the rest I've tried in the MKll (without caps) and the moment I hit play (Roger Waters "pros and cons of hitch hiking) I knew that the 8065 is here to stay... the detail, the texture and the clarity, the clarity, the clarity, the CLARITY! I never expected them to sound _this_ good....... the last time I tried them was in a WNA MKl with in / out caps..... in a _capless_ MKll these are unbeatable IMO and if there _is_ a better sounding chip (WNA compatible) out there It'll have to be something pretty bloody spectactular to top the AD8065. I hate buzzwords and these people who constantly say "wow" but, on this occasion, I'll break my own rule and just say "[size=medium]wow[/size]!" 

 The bad news...... WNA cannot source the 8065 at the present time so anyone wanting to try them will either have to get them from the AD sample program or source them somewhere else. A real pity as the AD8065 works _so_ well in the WNA MKll... it would be great if the kit came supplied along with the WNA s8d and AD-8065........ can't have your cake and eat it cest la vie 
	

	
	
		
		

		
		
	


	




 Oh well, there's not much more I _want_ or _need_ to do with my MKll now....... Looks like I'll be forced into enjoying the music and have to move on to some other project.

 It's been fun rolling opamps and stuff and I've really enjoyed the musical roller coaster ride! A _big_ thanks to David White of White Noise Audio and to _all of you guys _ who have made this thread so enjoyable and informative.

 I'm outta here to get down to some listening which, at the end of the day, is what it's all about 
	

	
	
		
		

		
		
	


	




 Mike.

 A few snaps of the 8065 on the WNA s8d adaptors: (scuse the pics, bad light)


----------



## l_simon_l

Wow mike, this sounds exciting. 

 What mods are done to your WNA in addition to changing the opamp to AD8065 and getting rid of output and input caps?

 Zobel Network? Removed lamps? 

 My WNA is currently all stock. Is the difference significant? If so, I just might have to make use of my soldering iron again 
	

	
	
		
		

		
		
	


	




 Edit: Oh... i can see what you did to the lamps in the picture


----------



## 12796

Pinkie,

 Let me present to you the REAL final opamp... the ad8067. 

 Its the ad8065 on steroids. 

 I may have a couple of spare pairs very soon as it wont work in the two riaa stages of the phono. Fancy a listen?

 What are you using in the rail splitter? I am using the lm6171 but it would be interesting to try the ad8065 there too. I will be interested to see if you or david can tweak more out of the ad8065 as well. 

 Regards,

 Nick.


----------



## PinkFloyd

Quote:


  Originally Posted by *l_simon_l* 
_Wow mike, this sounds exciting. 

 What mods are done to your WNA in addition to changing the opamp to AD8065 and getting rid of output and input caps?

 Zobel Network? Removed lamps? 

 My WNA is currently all stock. Is the difference significant? If so, I just might have to make use of my soldering iron again 
	

	
	
		
		

		
			



_

 

Hi Simon,

 Zobel fitted, removed lamps (replaced with ferrite inductors or zero ohm links) removed both input and output caps and yes IMO (to my ears) there is quite a vast improvement. The zobel is probably _unnecessary_ with FET opamps so if you just whip out _all_ three LM6171's and remove the output caps you're good to go. I find something like an opa 627 is good in the rail splitter.

 Mike.


----------



## l_simon_l

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Simon,

 Zobel fitted, removed lamps (replaced with ferrite inductors or zero ohm links) removed both input and output caps and yes IMO (to my ears) there is quite a vast improvement. The zobel is probably unnecessary with FET opamps so if you just whip out all three LM6171's and remove the output caps you're good to go. I find something like an opa 627 is good in the rail splitter.

 Mike._

 

Thanks! No I just have to find a source for the components... I think I live in the wrong country for DIY


----------



## Paco

Hello all,
 The AD8065 also was the best one in the MKI version to me (I was using it without input and output caps). I've finished with the “capless” MKII to use it as a preamp a couple of days ago and I have a question. I've measured TR2 and TR4 and they are at about 100ºC with case open and with an external temperature of about 25ºC. TR1 and TR3 are at about 90ºC. My question is... should I use heatsinks? I've seen that those transistors are rated at 150ºC but I think that once the case is closed and external temperature raise to 30ºC, they will be close to the maximum temperature... what do you think?

 Best regards,
 Paco


----------



## Henry Morgan

I recently tried the SOIC mounted AD8610 without caps in my WNA Mk2 & felt it was not quite as good as the 6171 with output caps. Tangent on Headwize seems to be able to supply the adapters for SOIC chips either mounted or unmounted. Shame I don't think he uses the AD8065 as I would like to give it a try!


----------



## Alick

Quote:


 Zobel fitted, removed lamps (replaced with ferrite inductors or zero ohm links) removed both input and output caps and yes IMO (to my ears) there is quite a vast improvement. The zobel is probably unnecessary with FET opamps so if you just whip out all three LM6171's and remove the output caps you're good to go. I find something like an opa 627 is good in the rail splitter. 
 

Bias current back to original level Mike? I've got the AD sample kit lying in a drawer at work and I'm hoping there's a pair of 8065's in there. I knew if I waited long enough I could ditch the output cap's ...


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Bias current back to original level Mike? I've got the AD sample kit lying in a drawer at work and I'm hoping there's a pair of 8065's in there. I knew if I waited long enough I could ditch the output cap's ..._

 

Yes Alick, bias back to normal. Things were getting pretty erm "warm" with the upped QC and AD843..... you're perfectly ok with the QC increase as long as the trannies are sinked and with winter coming up you may be glad of the extra heat 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## Alick

I seem to recall it was a hell of a struggle to get the heatsinks in, there being not much room for them. Hopefully, they'll come out easier, but I'll leave them in place until I know I'm happy with the sound (as I'm confident I will be) ... just in case. No output cap's - I can't wait.

 EDIT: I just reread your post (properly this time). I'll probably try it with the increased QC to start with as it's already set up that way.


----------



## PinkFloyd

Quote:


  Originally Posted by *Paco* 
_Hello all,
 The AD8065 also was the best one in the MKI version to me (I was using it without input and output caps). I've finished with the “capless” MKII to use it as a preamp a couple of days ago and I have a question. I've measured TR2 and TR4 and they are at about 100ºC with case open and with an external temperature of about 25ºC. TR1 and TR3 are at about 90ºC. My question is... should I use heatsinks? I've seen that those transistors are rated at 150ºC but I think that once the case is closed and external temperature raise to 30ºC, they will be close to the maximum temperature... what do you think?

 Best regards,
 Paco_

 

Hi Paco,

 I've measured mine in the past with ambient temperatures ranging from 20C to 30C and the trannies remain around the 80C - 85C mark irrespective and that's without heatsinks in place.

 I measured earlier with 2 meters and the results were pretty much the same:

 Left Channel with ambient temp. of 22C results:

 TR1 - 84C
 TR3 - 82C
 TR2 - 82C
 TR4 - 74C

 Right Channel with ambient temp. of 22C results:

 TR1 - 80C
 TR3 - 82C
 TR2 - 79C
 TR4 - 78C

 Your 90C doesn't seem "excessive" but 100C is certainly _pushing it _ a bit Paco. What values of resistor do you have in R5 & R6? They should be R5=120R R6=75R

 If you've upped the quiescent current by replacing R5 & R6 with 160R and 100R then you'll have to heatsink the transistors as the increased QC will cause TR1, TR2, TR3 and TR4 to run a lot hotter. If this is the case then heatsinks are essential. If you are running the amp at stock QC (R5=120R & R6=75R) and the temperature is in the high nineties then It's essential you heatsink them to preserve the working life of them. 

 Another thing worth trying is measuring the voltage across the 10R resistors... according to WNA it should be _around_ 500mV (measures 394mV on mine) also make sure the 10R resistors "are" 10R and not around 8R / 9R. If all the 10R resistors are lowered to say 8R this will also increase the QC.

 If you _have_ upped the QC then you either have to _heatsink_ the transistors or revert back to the original stock QC (R5=120R & R6=75R)

 Hope this is helpful.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I seem to recall it was a hell of a struggle to get the heatsinks in_

 

Not much room to manoeuvre in the MKll with components being pretty close together... heatsinking is "doable" but not with off the shelf sinks (Maplin. Raid etc.) hopefully if there is ever a MKlll David will allow a bit more breathing space and allowance for larger caps such as Cerafine or Black Gates etc.


----------



## PinkFloyd

Measuring DC offset:

 1: Multimeter set to 200mV on the DC range






 2: Turn amp on... nothing connected (no 'phones or interconnects etc.)

 3: probe between Sleeve and tip (ground & Right) on the headphone socket as shown:






 The reading should ideally be 0.00mV but seldom is.... anything below 20mV is perfectly acceptable (closer to 0.00mV ideally). Once you are happy that the offset is within limits then repeat the test but _this time _ with the source connected....... play a CD and then hit the pause button... now measure the offset with the CD player connected and disc on pause. If both measurements are pretty close to 0.00mV (say something like 3.74mV) then you're good to go! Another thing..... turn the volume control up and make sure the offset remains the same at all levels (it will if it's a FET opamp 

 Repeat the same for the left channel by probing between Sleeve and ring (ground & left) as shown:






 The reading between channels will invariably be different ie: L = 3.74mV and R= -0.05mV nothing to worry about here, perfectly acceptable.

 When probing connect the black lead to COM on your multimeter and the red lead to V. Always probe the sleeve (ground) with the black lead.

 Something along those lines and most opamps like OPA627BP generally measure around 0.07mV (or thereabouts) and some measure a perfect 0.00mV. LM6171 will measure something crazy like 800mV hence the need for DC blocking output caps or trimpots. The AD-8065 I have just inserted into the WNA measure 0.01mV (left channel) and 2.06mV (right channel) so the offset is VERY low and well within limits.... that's not to say that all 8065's will measure the same and you'd have pick through a few of them to select two that measured 0.00mV.

 That's the general idea and I'm sure there are more elaborate ways of measuring DC offset and better ways of explaining the procedure but this is all I've got in me at the moment (knackered) hope it helps.

 Mike.


----------



## Paco

Hi Mike,
 I've build the kit as it comes from WNA so I suppose that it has the standard quiescent current. I’m going to check this afternoon. In fact I've checked again and all the transistors are close to 100ºC (between 93 and 98 ºC). The only special think in my preamp is that the power supply has been fully developed to double monophonic (2 toroidals, two WNA Cascode power supplies and 2 rail splitters, one for each channel). I don’t know if this extreme power supply would cause this overheating but it shouldn’t as the Cascode power supplies are delivering +-24V. I’m going to put the heatsinks ASAP.

 Best regards,
 Paco


----------



## Alick

Paco, in the assembly instructions, David mentions that if you use a PSU providing greater than +/-15V, you will need heatsinks on Tr1 - Tr6. Sounds like you definitely need to fit them; check your instructions. I presume you're not using the rail splitter?


----------



## Paco

Hi Alick,
 Yes, it looks like it's the way to go. I've seen that some of you use clip tipe heatsinks (I think Mike do it)... do you have farnell or RS references for them? I'm using two rail splitters, one for each channel. By the way, I like the LM6171 in the rail splitter.

 Regards,
 Paco


----------



## 12796

I have tried opa627, ad825 and lm6171 in the rail splitter and preferred the latter. Has anyone tried ad843, ad847 or ad8065?


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I have tried opa627, ad825 and lm6171 in the rail splitter and preferred the latter. Has anyone tried ad843, ad847 or ad8065?_

 

Hi Nick,

 I've tried 627, 6171, 825, 8610, 8605, 843, 134, 811 etc. in the rail splitter. One of them smoked like a chimney I think it may have been the 811 (or was it the 843) I can't remember.

 ATM I've got 627 in the splitter along with your 8067 (gain of 10) and am just going to try the LM6171 with the 8067.

 8067 sounds very promising I'll leave it in the circuit for a couple of days then have a darned good listen to it once the dust has settled....... the house is on the market and I'm busy beavering away regrouting, painting, jet washing, filling black bags, hoovering, nailing, screwing, fitting lights, wallpapering and a host of other equally mind numbing tasks.... this is a pretty hectic period of activity (for me) and I can't wait till it's all finished so I can have a good session or two with the 8067.

 It "appears" stable with 10K resistors in R3 and sounded ok (listened to a couple of tracks) off out to grab an LM6171 and a bite to eat now and will report back probably early next week.

 All the best.

 Mike.

 PS: the offset of your two chips is -0.00mV and 0.07mV


----------



## 12796

Looking forward to it! Good luck with the move!


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_ Good luck with the move!_

 

Haven't got a clue where I'm going yet Nick but I'm going somewhere for sure. I've made a big change to my life so may as well change the location whilst I'm at it....... It'll probably be somewhere as far away from "civilisation" as possible. 

 Mike.


----------



## spendorspain

Hi head-fiers,

 Regarding the input and output caps, I believe that they are the limiting factor in the WNA hp amp.
 When I removed input caps the sound improved vastly, but I had to use output caps because the bad dc-offset behaviour of the LM6171. I was sure that the sound quality of Black Gate caps I used in C4 was beyond reproach, but a couple of simple experiments proved this was wrong. I began to believe that the sound was perhaps too nice and “uniform”. When I used other amp to drive my Grado HP-2, the recordings seemed more different and distinct one from another, so I suspect something was putting a little veil over them, a very charming and rounding veil, but a veil. Of course the amp did sound very well,
 but perhaps it wasn’t telling the whole truth of what there is in the recording. So I reconnect my cans to the Copland CTA501 valve power amp binding posts via an high quality attenuator. The result was a more live sound and the restored feeling that all recordings are clearly different, as if the acoustic personality of each were more clearly presented, even sounding coarser in some cases. Next, I made an experiment that I recommend to everybody that has removed the 4.7uF C1 input caps (a high quality Evox polypropylene film caps) and has them, unused, in the spare parts box. I soldered them across the C4 legs under the PCB, as a bypass cap. It seemed a too big cap for bypassing, but C4 has also a big value (1000uF in my amp), and I had at hand only the spare C1 to experiment, so I went ahead. The result was an improved sound, specially in extreme highs and in what could be called as the “aliveness” of sound. This impression is confirmed by nearly a month of listening to the “bypassed” amp. This disappointed me a little, because the Black Gates are touted as possibly the best electrolytics and they are very very expensive… It seems that they didn’t need a “band-aid” (the film bypass cap) to improve its sound, but IMHO this is not the case, and perhaps this is ever more important with the stock Nitai output caps. I’d like to know more opinions about this.
 As a result, I’m decided to build another WNA hp amp, this time “cap-less” and as simple as I can. No caps in signal path, no need for rail splitter (I’ll use a WNA Cascode psu to supply the +/0/- dc volts), no zobel network and the best parts I could find (there are only 23 per channel). I have already a pair of AD8610 chips (with extremely low dc-offset specs) mounted on Browndog adaptors and I’m going to order the rest of parts from several suppliers (WNA, Mouser, Percy…). I have no problem with resistors, capacitors and output transistors, but I have no idea of what are the exact references of the diodes D1-D2 and the constant current diodes I1 to I4. I’d be very grateful if somebody could tell me these references (type, maker, exact values). When finished, I hope to report about the differences (to my ears and with my system, of course) between the cap-less AD8610 WNA amp and the standard LM6171 plus output caps (note that even with the 100k trimpot and 10M resistor trick proposed by Pink Floyd to eliminate DC offset, it is necessary to use input caps). And I must add that the WNA hp amp I’m listening now, caps and all, is a very enjoyable and very good sounding little amp. Perhaps it’s just me and a case of “audiophilia nerviosa”… 
	

	
	
		
		

		
			





 Jose


----------



## PinkFloyd

Hi Jose the current regulating diodes are 3.5mA and 5.6mA made by Semitec. You can source them at Rapid for 55p each  






 The in / out caps certainly do throw a slight rose tinted veil over the music and it is well worth bypassing them (preferably with a zero ohm link!) try a 1uF poyprop and say a 200nF film cap if you're intent on keeping the 6171 in the circuit.

 From memory, the AD8610 wasn't anything spectacular but I tried it in a capped MKl so it'll probably sing a bit better with them removed. There is no need to have in / out caps if you're using a FET opamp so you must choose which FET opamp sounds the best to your ears. I'm currently enjoying the AD-8605 which sounds honest to the event and I like it. Nick has sent me a couple of AD8067 to try so I'll report back on them.

 Black gates are great in certain applications but I'm not sure the signal path is one of them...... caps in the signal path are always a compromise and I'm not conviced that the LM6171 (with caps) is anywhere near as good as a 8065 (without caps) for example.

 If you give me a couple of days I've got a few ideas for you to try out........ I _must_ get off to bed now else I'll be up all night hoovering and painting.

 Mike.


----------



## bludragon

Fitted the trim pots last night so I could remove the output caps and leave the LM6171 in place. Everything worked perfectly - adjusted the offset, waited till it warmed up, and then adjusted it again. After a couple of hours of it working away with no lid, decided to unplug it. 

 Now when I plug in the supplied power supply, it drops from 24V down to 3V. I tried a different 12V supply, and this works OK. I put a 1K Ohm resistor across the 24V supply, and its voltage didn't drop at all. So it seems more like something has gone wrong in the WNA which makes the power input look like a short at higher voltages??

 Will be investigating more fully tonight, but any suggestions as to what to check, or what might be wrong will be very much appreciated.

 Thanks.


----------



## StevieDvd

Have you got a ground wire on the volume pot? My WNA had a hiccup reently and after a long autopsy it was the wire that was part of the cause. This led Mike (Pinkfloyd) to have his doubts about the LM6171 as he has mentioned earlier in this thread.

 If you do have the wire there in case of 'hum' it's a quick check to do to eliminate it as a cause.

 Steve


----------



## bludragon

No ground wire. The mods I do have are:
 Zobel network
 incandescant lamp replaced with zero ohm link
 some of the caps bypassed smaller values.

 and now zero ohm link instead of output caps, and trip pots to adjust offset.

 I think its more likely something has died due to a possible short or other electrical zap when I was messing around with the top off, as it was working fine for a couple of hours.


----------



## 1UP

Jose, those bypass caps are huge! How tall is your case? 
	

	
	
		
		

		
		
	


	




 Which BGs were you using in which position, exactly?


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Have you got a ground wire on the volume pot? My WNA had a hiccup reently and after a long autopsy it was the wire that was part of the cause. This led Mike (Pinkfloyd) to have his doubts about the LM6171 as he has mentioned earlier in this thread.

 If you do have the wire there in case of 'hum' it's a quick check to do to eliminate it as a cause.

 Steve_

 

Not so much "doubts" about the LM6171 Steve just "puzzlement" when the **** hits the fan at times. David White reckons it's easier to design an amp than it is to pinpoint a fault..... seems to me there are no "obvious" places to look when a fault or weird noise develops it's just a case of process of elimination and sods law dictates that the _last_ part you replace is the bloody part that has failed or is misbehaving..... It's never the "first" part you check that's faulty.... oh no, never works out like that!

  Quote:


  Originally Posted by *bludragon* 
_Will be investigating more fully tonight, but any suggestions as to what to check, or what might be wrong will be very much appreciated.
_

 

Your finger is the best (and cheapest) tool to use to begin with. Possible that one or more of the transistors has packed in... if they are working they'll be hot to the touch (the ones in the rail splitter will be cool so that's ok) If you probe one (ampside) with your finger and it's cold then you can assume that it's not working....... if cold then replace and see what happens.

 I've e-mailed Dr. David with your symptoms...... maybe he can throw some light on things 
	

	
	
		
		

		
		
	


	




 Mike.

 EDIT: Are you using one of those "powerpak" PSU's by any chance? Just re-read your thread and you say the amp works _ok_ with a _different_ PSU?? what PSU does it work OK with and which one doesn't it work with?


----------



## bludragon

Thanks Mike, I've just spend the last couple of hours with it, and have come to the (possibly incorrect) conclusion, that the fault is in the rail splitter section. With no load on it, it seems to output the correct voltage, but as soon as I attach either one of the amp channels, it drops down to +-1 Volt. 

 I happen to have a +-12V regulated psu, and with that powering both channels (bypassing the rail splitter) everything seems ok.

 I'm about to try plugging some (cheap) headphones in to see what happens...

 EDIT: ok, seems to work when bypassing the railsplitter. As its screwed back to gether, I'm gonna leave it at that for tonight, and troubleshoot the railsplitter later.


----------



## bludragon

Just seen your edit - The problem occurs when using the 24V powerpack that comes with the kit - so far I've been having fairly decent results with it. Last night I tried with a different 12V powerpack, and things seemed to work ok. However, there doesn't seem to be anything wrong with the 24V powerpack. At the moment it would seem the railsplitter goes into short circuit mode when asked to supply more than a certain amount of current


----------



## PinkFloyd

Quote:


  Originally Posted by *bludragon* 
_Just seen your edit - The problem occurs when using the 24V powerpack that comes with the kit - so far I've been having fairly decent results with it. Last night I tried with a different 12V powerpack, and things seemed to work ok. However, there doesn't seem to be anything wrong with the 24V powerpack. At the moment it would seem the railsplitter goes into short circuit mode when asked to supply more than a certain amount of current 
	

	
	
		
		

		
		
	


	


_

 


 Hi Bludragon,

 Had a word with David re: the power supply etc. the short of it is that certain power supply units can be problematic even with slight changes such as different opamps / layouts etc. I know, first hand, that the Mascot PSU is a no no with the WNA (ok for about 30 minutes and then it trips out) The fact that the "powerpak" _was_ ok and now isn't makes this a very tricky one to pinpoint but, basically, these things happen. Remember the LM6171 is pretty cranky / insanely fast and any changes to the layout can cause it to misbehave. 

 I know this sounds a bit vague but things like this sometime happen... even the way you wire the trimpots is going to play a part..... wiring needs to be kept as short as possible when using the LM6171..... try shifting one of the ampside opamps to the rail splitter and the one in the rail splitter ampside..... you'd be amazed just how often this does the trick 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## FritzS

My questions to David:
 Have you test some other output transistors - BD138/139 vs. Toshiba's SC2238 / 2SA968 or 2SA1837 / 2SC4793?

 Toshiba's 2SC2238 / 2SA968 have a higher ft - about 100 MHz

 What costs the headphone protection too - only PCB / complete kit - must I order only one or two for stereo?

 The answer:
  Quote:


 Hi Friedrich,

 I must admit that I haven't got around to trying any output devices other than the BD139/BD140, but its possible that higher gain and/or ft devices might make a small difference. 
 The headphone protection unit costs £25 as a kit but at present I don't offer the pcb separately.
 Regards, David


----------



## spendorspain

Hi, 1Up,

 The red Black Gates (1000uF/25V Nx bipolar type) are in C4 position, the DC-blocking cap in series with the output, hence its great influence in the final sound of WNA amp. As you can see in the picture, I had to solder the IC bypass small cap C2 in PCB underside to make room for C4. My case is very tall simply because I have removed its lid 
	

	
	
		
		

		
		
	


	




. When I decided to bypass C4 (with the 4.7uF polypropylene I had at hand after remove it from C1 position), I thougth it would be only a brief test, so I secured the PCB to the open case, after soldering the bypasses, with small blobs of Blu-Tack. It didn't look pretty, but it worked. However, because of the big and unexpected improvement in sound, I have listened to the amp without lid for several weeks. With a more careful layout and bending the cap leads I think it would be possible to install these big film bypasses in a space of just 2-3 cm under the PCB, so a very big case would not be necessary, just taller stand-offs.

 I've already installed the AD8610 in IC1 position, and I've made a temporary wire arrangement to compare the sound with and without output caps, just to hear the effect of BG in C4. To hear the amp with caps, I connect the cable to headphone socket to the P2 pin header (the normal way); to hear it without caps I connect that cable to the new output pin header I've soldered to another point in PCB just before the output caps (see picture). The new IC is burning-in but, as I've got a cold and my hearing is well below par, I'm not going to evaluate the sonic changes at the moment. What I do recommend to you is to bypass C4, just for hearing the effect by yourself. In my amp and to my ears the improvement was not subtle.

 And now a question for the "WNA-meister" 
	

	
	
		
		

		
		
	


	




 , i.e. Pink Floyd. Thank you for your previous answer, but I'd like more information about these diodes (I1, I2, D1 and D2), if I order them from other supplier than Rapid. I'm unfamiliar with diode terminology (I've seen references like 1N4148, 1N5711, 1N4007, etc., black or glass bodies, constant current, zener and other types, different values, ratings...), so any explanation and specific references would be welcome.

 Best Regards,
 Jose


----------



## bludragon

Hi Mike, thanks for your help. Haven't had a chance to play with it over the weekend. Will let you know if I managed to figure out the problem. At the moment I'm just running it with the rail splitter bypassed, but it does mean I have an ugly nest of wires hanging out the back hooked into a powered prototyping board.


----------



## Paco

Hi all,
 I’m attaching some photos from my preamp. It has been running for a week now and I’ve done some test with rail splitter op-amp. The LM6171 is the winner to my ears here. I’ll start with some test in the amp section this week (right now it’s working with the OPA627).
 Comparing the MKII with the PSU that you can see on the photo with the MKI (capless modified for LM6171 version, using AD8065) with a more conventional PSU (one WNA Cascode Power Supply for both channels) the MKII is in other league. The clarity and tonality are superb and dynamic is just impressive. OPA627 sounded dark and lack dynamic in the MKI but I’d a very good surprise in the MKII as here I had a very different picture. The AD8065 was much better in the MKI… if the improvement once I mount the AD8065 in the MKII is similar this will be like a dream come true!


----------



## 12796

I am using the mk 2 with lm6171 rail splitter and ad8065 signal. You wont be dissapointed! Have you tried ad8065 in the rail splitter at all?


----------



## PinkFloyd

Quote:


  Originally Posted by *Paco* 
_Hi all,
 I’m attaching some photos from my preamp. It has been running for a week now and I’ve done some test with rail splitter op-amp. The LM6171 is the winner to my ears here. I’ll start with some test in the amp section this week (right now it’s working with the OPA627).
 Comparing the MKII with the PSU that you can see on the photo with the MKI (capless modified for LM6171 version, using AD8065) with a more conventional PSU (one WNA Cascode Power Supply for both channels) the MKII is in other league. The clarity and tonality are superb and dynamic is just impressive. OPA627 sounded dark and lack dynamic in the MKI but I’d a very good surprise in the MKII as here I had a very different picture. The AD8065 was much better in the MKI… if the improvement once I mount the AD8065 in the MKII is similar this will be like a dream come true!_

 

Nice Paco! Very nice indeed! Let us know how you find the 8065 in the MKll


----------



## PinkFloyd

Quote:


  Originally Posted by *spendorspain* 
_And now a question for the "WNA-meister" 
	

	
	
		
		

		
		
	


	




 , i.e. Pink Floyd._

 

Jeez I must use my reading glasses, I thought that read "WANK-meister" 
	

	
	
		
		

		
		
	


	




 Thanks for the compliment Jose but I'm probably closer to the latter than the former... I'm just your average punter with a soldering iron..... there's no black magic involved in soldering a WNA kit together, the _meister_ is Snowy (Dr. White) I'm just a mere twit with an obsessive compulsive soldering disorder 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *spendorspain* 
_ Thank you for your previous answer, but I'd like more information about these diodes (I1, I2, D1 and D2), if I order them from other supplier than Rapid. I'm unfamiliar with diode terminology (I've seen references like 1N4148, 1N5711, 1N4007, etc., black or glass bodies, constant current, zener and other types, different values, ratings...), so any explanation and specific references would be welcome._

 

Really..... what is there to say? D1 and D2 are 1N4148 signal diodes housed in a DO-35 package (a penny each) Bog standard 1N4148






 I1 is a 3.5mA Current regulating diode in an axial package.
 I2, I3 and I4 are 5.6mA Current regulating diodes in an axial package.






 Just make sure they are inserted with the correct orientation on the board (the black line on the diodes goes to the white line side of the PCB) this is clearly marked so you won't have any problems figuring out orientation.

 Not much else I can say on the WNA diodes Jose, it's all explained in the manual along with part types.

 All the best.

 Mike.

CRD description here
1N4148 description here


----------



## spendorspain

Hi, head-fiers.

 Thank you very much for the info, Mike. However, when I registered in Rapid to order from them, I've seen that the minimum order for outside UK mainland shippings is GBP 500 (!!) 
	

	
	
		
		

		
		
	


	




 I can't believe it. It's a huge amount that it is impossible to reach for an average DIY builder... 

 My first impressions of AD8610 aren't promising. It seems a dull and grey performer compared to LM6171 plus output caps... In your opinion (subjective, of course, but very valuable), which is the more alive/bright sounding op-amp for IC1 position? Any suggestions...? Where can I find AD8065 for cap-less use in WNA amp?

 Regards,
 Jose


----------



## 12796

I too found the ad8610 to be a bit dull and grey and with some very disconcerting colouration. Better than the opa627 but not by much.


----------



## PinkFloyd

Quote:


  Originally Posted by *spendorspain* 
_Hi, head-fiers.

 Thank you very much for the info, Mike. However, when I registered in Rapid to order from them, I've seen that the minimum order for outside UK mainland shippings is GBP 500 (!!) 
	

	
	
		
		

		
		
	


	




 I can't believe it. It's a huge amount that it is impossible to reach for an average DIY builder..._

 

How many do you need Jose? I'll get them for you from Rapid next time i'm ordering something and I'll ship them over to you no probs..... just let me know and we can get the ball rolling. Alternately WNA sells them and ships to Spain with no minimum order quantity. Catalogue here

  Quote:


  Originally Posted by *spendorspain* 
_My first impressions of AD8610 aren't promising. It seems a dull and grey performer compared to LM6171 plus output caps... In your opinion (subjective, of course, but very valuable), which is the more alive/bright sounding op-amp for IC1 position? Any suggestions...? Where can I find AD8065 for cap-less use in WNA amp?_

 

Yeh, the 8610 is pretty lame compared with the LM6171 but the 8065 is a lot better. Register with Analogue Devices  and order the AD8065AR as samples.. they'll send you some free of charge for evaluation.


----------



## 12796

How are you getting on with the ad8067 Pinkie? Had a chance to look at it? My inbox was full previously ... sorry about that.


----------



## StevieDvd

Vick,

 I think he's sold his WNA and will build another later, once he's moved.

 Just as I've got two AD8065 delivered the 8067 pops up 
	

	
	
		
		

		
		
	


	




 Should I just throw them in the bin or try soldering such small chips 
	

	
	
		
		

		
		
	


	




 When I get my self sorted out I'll get some of Dr White's adapters and have a bash at the smd soldering and see how the AD8065 sounds. 

 Are the 8067s much better or just a tad?

 Steve


----------



## Alick

I think Mike's too busy with his new toy.




  Quote:


 Should I just throw them in the bin or try soldering such small chips

 When I get my self sorted out I'll get some of Dr White's adapters and have a bash at the smd soldering and see how the AD8065 sounds. 
 

The SMD soldering isn't too bad. You just need a fine bit, a steady hand, some fine gauge solder (David supplies suitable silver solder with the adaptors) and some fine solder wick is a good idea just in case you overdo it. The WNA adaptors are very good and easy to work with. I'm still auditioning the 8065s, but thus far, I'm quite impressed.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_How are you getting on with the ad8067 Pinkie? Had a chance to look at it? My inbox was full previously ... sorry about that._

 

Hi Nick,

 I Pm'ed you but your box _was_ full. I gave up on the 8067 as it kept oscillating and playing up so it's probably great for mobile phones and stuff but not ideal for a headphone amp... from what I could hear the AD8065 is a much better sounding device. What's your address Nick I'll get your 8067's back over to you.

  Quote:


  Originally Posted by *StevieDvd* 
_I think he's sold his WNA and will build another later, once he's moved._

 

Yeh, she's on her way to Australia (probably on a Jumbo Jet as I type) I think I'll wait and see if a MKlll comes out.... no point building one that's exactly the same again.

  Quote:


  Originally Posted by *StevieDvd* 
_Just as I've got two AD8065 delivered the 8067 pops up 
	

	
	
		
		

		
		
	


	




 Should I just throw them in the bin or try soldering such small chips 
	

	
	
		
		

		
		
	


	


_

 

Stick with the 8065 man....... direct drop in, no fuss and sounds good into the bargain.

  Quote:


  Originally Posted by *Alick* 
_I think Mike's too busy with his new toy.



_

 

_Busy_? I'm having a whale of a time with this puppy Alick... your amp sure has landed on its feet and is enjoying all the attention I'm giving it!

 Eargasms, spine tingles, goose bumps.... she delivers them all and in bucketloads and is responding favourably to each and every tweak! (what a powerhouse!!) Got a pair of Amperex Bugle Boys (and a few other goodies) on the way and am just _enjoying_ every moment with the V2 Alick... no, I'm not giving it back so there!


----------



## Alick

You do realise it was just a loan?


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_You do realise it was just a loan? 
	

	
	
		
		

		
		
	


	


_

 






 ummmmm...... I can "redo" everything apart from the two 20mm holes I cut out of the top of the enclosure 
	

	
	
		
		

		
		
	


	




 Hope you like holes?


----------



## spendorspain

Hi, head-fiers

 I have some comments about the AD8065 op-amp used as IC1 in WNA mkII headphone amplifier (the IC in the rail splitter is a LM6171). I’ve modify my amp with new wiring to make it very easy to change from the standard cap-coupled output to a direct output (see pictures)and I’ve extensively compared the “capless” AD8065 with the LM6171 (plus the C4 mandatory output cap). 

 When first heard through the AD8065 all recordings seem more detailed, dynamic, direct and alive, but extended hearing reveals some shortcomings. True, the AD8065 is more detailed (perhaps simply due to the absence of a big electrolytic cap in the signal path) but also a little “dry”, with the music perhaps too “in-my-face”. Normally it is not artificial or etched, but in some recordings this closer perspective is uncomfortable. The soundstage is a little flat, without the depth I think suits better to the classical music I listen to (I know that headphone listening “soundstage” is a controversial issue, but my Grado HP-2 are very spacious-sounding). Perhaps the AD8065 really needs crossfeed (I’m going to try the Linkwitz crossfeed circuit available in the net as soon as possible). The bass is extremely precise and taut, not loose at all, but this is again a disadvantage more often than not for classical, which need IMHO a more expansive and deeper, however less controlled, bass (the bass that a symphony orchestra produces in a big concert hall is deep and a little loose, very different I think to the rock, pop or jazz bass which has more punch). 

 The LM6171 is less detailed (but not much if the C4 output cap is bypassed with a good film type), and more forgiving. It is laid-back, rounder, a little more soft-sounding (a rose-tinted view, as Mike said), and more emotionally involving for me (I’m trying to be as objective as I can, but this is the word that comes to my mind for describing the LM6171 sound). Perhaps the use with other musical styles or headphones, or playing with other elements (adding crossfeed or using different cables), could lessen the AD8065 shortcomings, but at the moment I prefer the LM6171. 

 And now I have a couple of doubts I hope you can help to clarify. A very tempting experiment is to avoid the output cap C4 when LM6171 is used. I don’t understand how the “100k trimpot + 10M resistor” trick works, but searching in the old WNA MkI posts I’ve found this opinion of Dr White himself: 
 “As a couple of people have pointed out you can increase the value of the feedback resistors ( say X10 ) to fix the dc offset problem and guarantee unconditional stability, as others have done with the LM6171. The problem with doing this is that it slugs the bandwidth of the LM6171 and it doesn't sound so good. I've tried using a couple of resistors and a potentiometer to zero out the dc offset but its not very good because the offset drifts with temperature. The only satisfactory way to zero out the offset is by using another opamp as a servo. Unfortunately the effect of dc servos is even worse, sonically, than using coupling capacitors. So, inelegant though it is, it looks like the coupling capacitor on the output is the best all round compromise." 
 Do you think the “trimpot trick” does slug the LM6171 bandwith (perhaps the feature responsible of their very special sound)? When using the trimpot, is it mandatory to use the input cap C1? If so, the problem is that with LM6171 there is always a cap in signal path, in input side (with the trimpot) or in the output side (as standard), or even in both sides (worst-sounding but bullet-proof).

 And, lastly, I have a doubt (or more precisely, a concern) about the AD8065. When I powered it for the first time, I heard a thump at turn-on (not too worrying, I thought). I left the amp on continuously for two weeks or so, burning-in, enjoying it and taking the listening notes I’ve posted above, but when I turned it off I heard a very, very loud thump that really scared me. Just for test it, I turned on and off the AD8065-WNA amp with output caps with the same result: a thump in both channels at turn-on and a much more loud thump at turn-off. 
	

	
	
		
		

		
		
	


	




 Is this normal? With LM6171 these thumps are nearly inaudible. I was so afraid that, in fact, another time I wanted to hear to the AD8065-WNA amp I switched it on with the headphones disconnected (there are dummy resistors in its output socket) and I plugged them in 10 seconds later with no music playing. Is this dangerous for the amplifier?

 Thank you for your help and best regards
 Jose


----------



## FritzS

Quote:


  Originally Posted by *spendorspain* 
_Attached Images 
 WNA_outputs.jpg (23.9 KB, 11 views) 
 WNAc_noOutCaps.jpg (19.7 KB, 8 views) _

 

Jose please can you post the images again - I cannot open it.


----------



## spendorspain

Quote:


  Originally Posted by *FritzS* 
_Jose please can you post the images again - I cannot open it._

 

Hi, Fritz

 I'm sorry, but I can't post the pictures again because the system doesn't allow to post attachments that they are already in the thread. However, I (and others) have no problem for opening them and perhaps is a problem with your browser configuration. 

 Regards
 Jose


----------



## FritzS

Quote:


  Originally Posted by *spendorspain* 
_Hi, Fritz
 I'm sorry, but I can't post the pictures again because the system doesn't allow to post attachments that they are already in the thread. However, I (and others) have no problem for opening them and perhaps is a problem with your browser configuration.
 Regards
 Jose_

 

Hi Jose
 I found the reason - my firewall - ZyWALL 5 - use an IDP / INTRUSION DETECTION AND PREVENTION 
 - I disabled this and could download the pics. But I talk about with the ZyXEL developer --> this is another story


----------



## FritzS

Quote:


  Originally Posted by *spendorspain* 
_Hi, head-fiers
 I have some comments about the AD8065 op-amp used as IC1 in WNA mkII headphone amplifier (the IC in the rail splitter is a LM6171). I’ve modify my amp with new wiring to make it very easy to change from the standard cap-coupled output to a direct output (see pictures)and I’ve extensively compared the “capless” AD8065 with the LM6171 (plus the C4 mandatory output cap). Jose_

 

Have you test AD8065 vs AD843 vs LM6171 vs SA5534/SE5534?

 With caps - you use Black Gates (1000uF/25V Nx bipolar type) are in C4 position? Bypassed? 
 The other electrolytic-caps are from/types?


----------



## spendorspain

Quote:


  Originally Posted by *FritzS* 
_Have you test AD8065 vs AD843 vs LM6171 vs SA5534/SE5534?

 With caps - you use Black Gates (1000uF/25V Nx bipolar type) are in C4 position? Bypassed? 
 The other electrolytic-caps are from/types?_

 


 Hi Fritz

 I've tested only AD8610, AD8065 and LM6171. 
 AD8610 is lifeless, lethargic and dead for my musical tastes and headphones (Grado HP-2 recabled with silver wire). Its only virtue was a good midband, with good voices, but no high-end detail or space. It seems that in other amplifiers this op-amp shines (its specs are very good), but not in my case.
 Regarding AD8065 and LM6171, see my previous post.

 The C4 cap is a BG bypassed with the EvoxRifa 4.7uF polyprop cap originally in C1 position (I had only these for trying the bypassing, but I'll order some others to experiment) and it does improve the sound in the highs and in the detail retrieval. The other caps are the original Rubycon ZA (not yet bypassed).

 BTW, Have you, or somebody else, any idea about the loud thump at AD8065 turn-on and -off? It puzzles me. I've measured offset and it is OK (1 and 8 mV).

 Regards
 Jose


----------



## PinkFloyd

Quote:


  Originally Posted by *spendorspain* 
_BTW, Have you, or somebody else, any idea about the loud thump at AD8065 turn-on and -off? It puzzles me. I've measured offset and it is OK (1 and 8 mV).
_

 

Hi Jose,

 The thump is perfectly normal and will not damage your headphones, don't worry! You'll notice the amp thumps with most opamps but is most noticeable with the 8065, I asked David about this and he said it was ok... can't remember the reason why I will ask him........ anyways don't worry about it it's just a short thump like someone whacking a drum (probably a _very_ short dose of DC at turn on / turn off) it won't damage your headphones. You can always "hot plug" your 'phones once the amp is turned on.


----------



## spendorspain

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Jose,

 The thump is perfectly normal and will not damage your headphones, don't worry! You'll notice the amp thumps with most opamps but is most noticeable with the 8065, I asked David about this and he said it was ok... can't remember the reason why I will ask him........ anyways don't worry about it it's just a short thump like someone whacking a drum (probably a very short dose of DC at turn on / turn off) it won't damage your headphones. You can always "hot plug" your 'phones once the amp is turned on._

 



 Thank you very much, Mike. The thump is much, much louder than with AD8610 or LM6171, and real loud and frightening (perhaps my 32 ohm-impedance Grados are more susceptible or I'm not an enough brave headfier 
	

	
	
		
		

		
		
	


	




). 

 Perhaps the best answer to this problem, whatever it is its cause, is the easier: to unplug the headphone before switch-off and after switch-on with no signal present (potentiometer set to max attenuation). After all, this is what a delay-relay does in many amplifiers: connect the load several seconds after turn-on and viceversa. With the dummy resistors in the socket the amp never sees no load at its output, and the brief contact that is made between "left live" and "right live" and ground (i.e.: a brief short-circuit in both channels) when pushing the plug into the socket every time I want to listen to the amp is inoffensive if there is no music playing. Am I right?

 I've just measured DC offset at output socket without output capacitor and my multimeter read as follows: 

 channel A: 0.20 mV at turn-on and 0.98 at turn-off
 channel B: 0.88 mV at turn-on and 0.488 mV at turn-off 

 It seems the AD8065 in channel B has a strange DC behaviour. Do you think it is defective? I've not measured DC offset with output caps, but I've heard the loud thump at turn-off even with them in place (but with output caps no DC is allowed to pass through them to headphones, isn't it?), and perhaps here lies another problem. If the cap-less amp is unexpectedly turned off (a power cut, for example), half a volt of DC goes to the headphones still plugged into it, which is bad, however brief is this condition. What do you think about it? (I know: I'm a chicken 
	

	
	
		
		

		
		
	


	




 )

 Best regards
 Jose


----------



## FritzS

some about caps - but in german 
	

	
	
		
		

		
		
	


	




http://www.fragjanzuerst.de/iz/audiokondensatoren.pdf
 Elektor jan. 1987

http://www.audiomap.de/forum/index.p.../mesg_id/17774
 ... der mir mit Abstand sympathischte Bypass C ist der NX 0,1er von Black Gate. Wenn eine Spannungsfestigkeit von 50 Volt reicht und dir der Preis nicht zu hoch ist ( www.audiotuning.de), dann ist das ein ernsthafter Kandidat
 ...aber der 0,1er NX ist wirklich ´ne Wucht! Für 2,60€ das Stück bringt er genau so viel, wie 8€ teure Supreme oder Auri-Cap.


----------



## FritzS

Quote:


  Originally Posted by *spendorspain* 
_Thank you very much, Mike. The thump is much, much louder than with AD8610 or LM6171, and real loud and frightening (perhaps my 32 ohm-impedance Grados are more susceptible or I'm not an enough brave headfier 
	

	
	
		
		

		
		
	


	




). 
 Best regards
 Jose_

 

The way out - build a turn-on delay muting and DC offset protection circuit like
http://www5.head-fi.org/forums/showthread.php?t=119066
http://headwize.com/ubb/showpage.php?fnum=3&tid=5866
http://www.amb.org/audio/epsilon12/

 or from Dr. White
http://www6.head-fi.org/forums/showp...&postcount=433


----------



## PinkFloyd

Answer from David re: "thump" as follows:

"You get this with direct coupled versions of the headamp because there is a very brief instant of dc offset before the amp settles to its normal operating condition. The only way to fix it is to arrange for either the power to ramp up slowly or the amp to turn on gradually. Other than to use a headphone protection unit, there isn't an easy way to accomplish this with the system as it stands. Fortunately the thumps don't do any harm to your headphones."

 Well, there you have it Jose. Far from ideal as far as you're concerned and maybe the headphone protection unit should be incorporated into the kit or a MKlll designed with power which ramps up slowly. As David says, this will not damage your headphones but I can appreciate your concern especially if you're using mega buck headphones.... the last thing you want to hear is a loud "crack" every time you turn the amp on or off.

 The cheapest / easiest solution is to keep your amp permanently powered up or to hot plug the headphones once the amp is powered up and to remove them before switching it off....... you've got the dummy load resistors on the head socket and (unless you're really ham fisted) you won't short the amp by plugging / unplugging the 'phones with it switched on...... I _never_ switch an amp on with the headphones plugged in and I _always_ turn down the volume and remove the headphones before switching it off...... it's always worked fine for me (touchwood!)

 If you think the WNA is weird you want to try the X-Can V3! switch it on and there's nothing at all for about 10 seconds..... switch it off with the 'phones plugged in and you get a funny "whoosh" sound...... well cool! Not as dramatic as a loud "crack" but fun nonetheless 
	

	
	
		
		

		
		
	


	




 All this is making me want to reach for the soldering iron and make another kit 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


----------



## nph134

Well I've just spent all morning reading this thread...couldn't stop once I'd started hehe!

 I'm very impressed with the interesting and informed posts especially by you pinkfloyd. It's also nice to see someone who is obviously quite a technical person not being blinkered to the more subjective aspects of music.

 I've just ordered some HD650s and am getting a WNA headphone amp for my xmas prezzie (perk of having David as a father). Hammond case, stepped attenuator...the works. After I have them and have "tested" them I'll hopefully have something of a little more substance to add here.


----------



## PinkFloyd

Quote:


  Originally Posted by *nph134* 
_Well I've just spent all morning reading this thread...couldn't stop once I'd started hehe!_

 

Welcome to Head-Fi nph134 
	

	
	
		
		

		
		
	


	




 All morning reading this??? man it must be dull where you live 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *nph134* 
_I've just ordered some HD650s and am getting a WNA headphone amp for my xmas prezzie (perk of having David as a father). Hammond case, stepped attenuator...the works. After I have them and have "tested" them I'll hopefully have something of a little more substance to add here._

 

Nice one! try and persuade him to shove a cascode PSU into your stocking too 
	

	
	
		
		

		
		
	


	




 I'll probably treat myself to another WNA for Christmas... boxing day is no fun unless you're soldering!

 Have fun with the amp and 'phones and let us know how you're getting on with them.

 All the best.

 Mike.


----------



## FritzS

Have anyone tested Panasonic FC instead of Rubycon or Nichicon electrolytic capacitors?


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Have anyone tested Panasonic FC instead of Rubycon or Nichicon electrolytic capacitors?_

 

Yeh man, Panasonic FC is probably my favourite capacitor and I have used it extensively in amps like the X-Can with very good results indeed! I would certainly try it in the WNA the only reason I didn't try it was the LM6171 wasn't too keen on low ESR caps in the MKl so I ruled the FC's out. 

 They should be fine in the MKll and their signature is very liquid, flowing and smooth.... lovely caps


----------



## PinkFloyd

I just noticed that all of the pictures I had posted in this thread were not showing, I've fixed the problem and they should all now be visible throughout the thread


----------



## GoRedwings19

Hi Mike (pinkfloyd) how would you describe the sound of the WNA 2 compared to the version 1.?


----------



## PinkFloyd

Quote:


  Originally Posted by *GoRedwings19* 
_Hi Mike (pinkfloyd) how would you describe the sound of the WNA 2 compared to the version 1.?_

 

Hi Mike,

 I've had the pleasure of listening to the MKl and MKll back to back and to be honest there's very little in it. That is, of course, the MKl with LM6171 and not the standard Mkl which came with OPA134 or OPA627 opamps... the MKll is streets ahead of the _original _ Mkl and features a capacitance multiplier etc. but compared to a MKl with LM6171 and associated tweaks it's not night and day but, on the whole, I think I prefer the delivery of the Mkll to the MKl.... it does everything the MKl does but with slightly more balls... that's as best as I can describe it from memory.

 All the best.

 Mike.


----------



## FritzS

BD 139/140 is runnig out - RS Austria have it not in stock,
 similar (and newer) is BD 239/240 (B,C).

 What value of HFE is recommend? -xx is the HFE type
 BD139, BD139-10, BD139-16
 BD140, BD140-10, BD140-16


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_BD 139/140 is runnig out - RS Austria have it not in stock,
 similar (and newer) is BD 239/240 (B,C).

 What value of HFE is recommend? -xx is the HFE type
 BD139, BD139-10, BD139-16
 BD140, BD140-10, BD140-16_

 

Case style T0-126

 Rapid have them BD139 BD140

White Noise Audio also supply them

Maplin also sell them

 All the best.

 Mike.


----------



## skyskraper

what about farnell? 
http://at.farnell.com/jsp/home/homepage.jsp


----------



## Loko

Hello there,

 Well I got a pair of Sennheiser HD595's bout 8 weeks ago and I have to say I'm falling in love with the whole head-fi thing again! 
	

	
	
		
		

		
		
	


	




 Recently moved house and I don't really have enough room to place my acoustic energy floorstanders in the entertainment room with pc & hi-fi. Hence I gave the Senn's a go after meaning to buy another seat of headphones after my old faithful AKG's passed away.

 Anyway! Digressing, after burn in I'm quite enjoying playback from my Sony CDP-XB930 (great little cd player on a side note) and I was keen to get a headphone amp. So, after reading away for a few weeks in the various forums/sites (including Rock Grotto, nice work there Pinkie) I thought I'd have a go at building a WNA mk II amp. Got in touch with Dr. White and made a payment into his account last week but since haven't heard anything back from him! I hope I got the right guy! 
	

	
	
		
		

		
		
	


	



 Anyone know if he's away somewhere? Seem to have trouble getting through to email him, couple messages bounced. 

 That aside, any tips on putting the kit together? After reading a lot, what op amps do you think I should use? I'm confused! 
	

	
	
		
		

		
		
	


	



 Also any recommendations on caps? I thought I may give some standard black gates a go, since I can source them cheap from work.

 Look forward to your opinions. See you around here more...

 Loko

 (I feel a horrible DIY addiction coming on...)


----------



## PinkFloyd

Quote:


  Originally Posted by *Loko* 
_





 Hello there_

 

Hi Loko! Welcome to Head-Fi 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *Loko* 
_Well I got a pair of Sennheiser HD595's bout 8 weeks ago and I have to say I'm falling in love with the whole head-fi thing again! 
	

	
	
		
		

		
		
	


	


_

 

Get out while you can..... it's addictive here! 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *Loko* 
_Anyway! Digressing, after burn in I'm quite enjoying playback from my Sony CDP-XB930 (great little cd player on a side note) and I was keen to get a headphone amp. So, after reading away for a few weeks in the various forums/sites (including Rock Grotto, nice work there Pinkie) I thought I'd have a go at building a WNA mk II amp. Got in touch with Dr. White and made a payment into his account last week but since haven't heard anything back from him! I hope I got the right guy! 
	

	
	
		
		

		
		
	


	



 Anyone know if he's away somewhere? Seem to have trouble getting through to email him, couple messages bounced._

 

I was chatting to David this afternoon Loko and his ISP has been suffering some technical problems with their e-mail..... they are working on it and things should be back to normal with his e-mail soon 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *Loko* 
_That aside, any tips on putting the kit together? After reading a lot, what op amps do you think I should use? I'm confused! 
	

	
	
		
		

		
		
	


	



 Also any recommendations on caps? I thought I may give some standard black gates a go, since I can source them cheap from work._

 

I'd start with the kit in stock form (LM6171 opamp) and build it as per the manual says.... sounds awesome. Once you've had the amp for a while you can either just enjoy the music or try rolling some opamps etc. I'd definitely build it up as the manual says to start with though just so you can get a feel of it.

 As for caps.. board space is pretty tight so "huge" exotics like Black Gates are probably a tad on the large size. There was a tendancy for the LM6171 to oscillate in the Mkl if you used low impedance caps but that doesn't apply to the MKll so really you can use any cap of your choice. I've used Cerafine, Nichicon Fine Gold and Rubycon caps and they all perform very well.... you may want to try the Panasonic FM series of capacitor, I've tried them in another amp and they are absolutely fantastic.... I fully intend to use them when I build my WNA over the Christmas period.


----------



## 12796

I am using black gates and vishays now - I will leave it a few weeks and describe my impressions.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_I am using black gates and vishays now - I will leave it a few weeks and describe my impressions._

 

Ah, so you decided to go with the Black Gates then? They take ages to form so, yes, you're probably best leaving them for a few weeks before they will reach their optimum performance level.

 All the best.

 Pinkie.


----------



## Loko

Pinkie!

 Thanks for your reply. It's too late now, the damage is done, I'm hooked again with the hi-fi virus... 
	

	
	
		
		

		
		
	


	




 Got my pcb today, little dissapointed after reading the instructions. There doesn't seem to be much detail there, maybe I'm just tiired after a long day! 
	

	
	
		
		

		
		
	


	




 Will give it a better read again tomorrow.

 Just collating the parts list in Farnell. Struggling to find 10ohm 0.1% resistors. Any suggestions where to get them from? AudioNotes tantalum's are £2 squid each! 
	

	
	
		
		

		
		
	


	



 They are in the signal path so I guess they'd rather be precision resistors and not 1p items! 
	

	
	
		
		

		
		
	


	




 Also, a question regarding the ferrite bead (R4), the instructions don't have any detail about it. Is there any particular ferrite grade required? What did you guys use?

 That's bout it for now. Will investigate the caps and let you know which I pick. Thanks again for your help PinkMeister 
	

	
	
		
		

		
		
	


	




 Cheers,

 Wako


----------



## PinkFloyd

Quote:


  Originally Posted by *Loko* 
_
 Got my pcb today, little dissapointed after reading the instructions. There doesn't seem to be much detail there, maybe I'm just tiired after a long day! 
	

	
	
		
		

		
		
	


	




 Will give it a better read again tomorrow._

 

There's really not a lot to read and unless you're using latching pins you can totally ignore the long screed that instructs you how to crimp a latching pin. The amp build is pretty much painting by numbers ie "solder C1 to position C1 on the board" and the only real part where you have to use your brain is when you connect the peripherals..... get those components onto the board and all will become clear the more you populate the board.

  Quote:


  Originally Posted by *Loko* 
_Just collating the parts list in Farnell. Struggling to find 10ohm 0.1% resistors. Any suggestions where to get them from? AudioNotes tantalum's are £2 squid each! 
	

	
	
		
		

		
		
	


	



 They are in the signal path so I guess they'd rather be precision resistors and not 1p items! 
	

	
	
		
		

		
		
	


	


_

 

10ohm is 10ohm period IMO unless you are one of these people who believes that low temp coefficient resistors make an audible difference in a headphone amp then it's ok for you to use bog standard 1% metal film resistors and match them up as close to 10ohm as you can. I certainly wouldn't pay 2 quid for one resistor (£2 for 500 yes) especially when the audible benefits of such a resistor equal "zilch".... unless you've got the ears of a bat 10ohm 1% metal film is perfectly acceptable. 

  Quote:


  Originally Posted by *Loko* 
_Also, a question regarding the ferrite bead (R4), the instructions don't have any detail about it. Is there any particular ferrite grade required? What did you guys use?_

 

It's an axial ferrite bead and I was the first to try one in this position (R4) the one I use is from Rapid  If you can't source them don't worry as a zero ohm link works fine in R4 (zero ohm resistor or a wire jumper) If you _can_ get hold of the ferrite inductors then you can use them in place of all the zero ohm links (jumper positions) across the board....... helps guard against RFI 

 [/QUOTE]

 You'll get 99% of what you need at Rapid components with the CRD's (CCD's) being probably the hardest parts to find........ here they are. you'll want the 3.5mA and 5.6mA "Axial" types.

 All the best.

 Mike.

 PS: if you find any parts of the instructions a bit hard to follow then just ask, there are plenty of people here who will help you out....... best thing to do for starters is to populate the board with the components and then take it from there.


----------



## FritzS

Hi,
 I order my kit now - but one question - have you any experience about other input caps - David use RIFA PHE 426 4,7uF 250V - but it gives some others (non expensive) such as RIFA PHE 450, WIMA MKP 4, WIMA MKP 10, Axon, Solen (from Percyaudio).

 As output cap I will use a Black Gate Nx 1000uF 25V non-polar - possibly bypassed with a Black Gate 10 uF 20 V N or a polypropylene

 For other electrolytics I want to use Nichicon FG / KZ bypassed

 My headphone is a Senn HD 600 
	

	
	
		
		

		
		
	


	




 PS: It is so silent here - Advent and Christmas season?


----------



## PinkFloyd

Quote:


  Originally Posted by *nph134* 
_I've just ordered some HD650s and am getting a WNA headphone amp for my xmas prezzie (perk of having David as a father)._

 

A little birdie tells me you got a lovely balanced WNA from Santa 
	

	
	
		
		

		
		
	


	




 Right...... where's the under the hood pics?


----------



## nph134

Quote:


  Originally Posted by *PinkFloyd* 
_A little birdie tells me you got a lovely balanced WNA from Santa 
	

	
	
		
		

		
		
	


	




 Right...... where's the under the hood pics? 
	

	
	
		
		

		
		
	


	


_

 

hehe I sure did, I'll do a little review and post some pics later today. 
	

	
	
		
		

		
		
	


	




 I'll maybe do it in a new thread though as santa also brought me a custom cable for my recently purchased HD650s, I also bought a Sony d-ne20 PCDP and a CMOY in a zippo. This was me lookin for a way to enjoy music still given that I'm travelling abroad lots just now with work and can't bring my beloved Tannoy Mercury M2 speakers and hi-fi seperates around with me


----------



## PinkFloyd

Quote:


  Originally Posted by *nph134* 
_hehe I sure did, I'll do a little review and post some pics later today. 
	

	
	
		
		

		
		
	


	




 I'll maybe do it in a new thread though as santa also brought me a custom cable for my recently purchased HD650s, I also bought a Sony d-ne20 PCDP and a CMOY in a zippo. This was me lookin for a way to enjoy music still given that I'm travelling abroad lots just now with work and can't bring my beloved Tannoy Mercury M2 speakers and hi-fi seperates around with me 
	

	
	
		
		

		
		
	


	


_

 

Great! get the pics up man, I can't wait to see the balanced WNA


----------



## nph134

Quote:


  Originally Posted by *PinkFloyd* 
_Great! get the pics up man, I can't wait to see the balanced WNA 
	

	
	
		
		

		
		
	


	


_

 

put a few quick photos in another thread...more to come later


----------



## FritzS

The kit arrived today - my first photos
http://www.stockhammer.at/hifi/wna.php

 I had a little problem - I can't get 100 nF polypropylene caps with RM 10 mm (RM = "Raster Mass"/"Raster measure"/"LEAD SPACING 10 MM") all distributors in Austria have only 5 mm RM (from WIMA, EVOX RIFA) - from others countries dispatch expensively for only 10 caps 
	

	
	
		
		

		
			




 I have only WIMA MKS 4 0,1 uF / 250 V with RM 10mm.
 Gives there any measurably or audibly difference between Metallized Polyester (PET) Capacitors and Polypropylene film (such as WIMA MKP 10) as you use?

 In the last moment I found this from Distrelec - PHE 450 
	

	
	
		
		

		
		
	


	



 #821525 PHE 450 100 nF 250 VDC 

http://www.wima.com/navig/pr.htm
http://www.wima.com/mks4.htm
http://www.wima.com/mkp10.htm
http://www.evoxrifa.com/cap_catalog/pulsecap/phe426.pdf
http://www.evoxrifa.com/cap_catalog/pulsecap/phe450.pdf

 What think you about compensation caps instead of the 330 kOHM as Jan Meier use them in 
http://www.meier-audio.homepage.t-on...eadamp1mk2.gif
 10 pF (first LM6171) and 47 pF (second LM6171)


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_The kit arrived today - my first photos
http://www.stockhammer.at/hifi/wna.php_

 

Nice one Fritz! looking good! that'll keep you busy soldering for a while 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *FritzS* 
_I had a little problem - I can't get 100 nF polypropylene caps with RM 10 mm (RM = "Raster Mass"/"Raster measure"/"LEAD SPACING 10 MM") all distributors in Austria have only 5 mm RM (from WIMA, EVOX RIFA) - from others countries dispatch expensively for only 10 caps 
	

	
	
		
		

		
		
	


	



 I have only WIMA MKS 4 0,1 uF / 250 V with RM 10mm.
 Gives there any measurably or audibly difference between Metallized Polyester (PET) Capacitors and Polypropylene film (such as WIMA MKP 10) as you use?_

 

I used all metallized polyester in one of my WNA amps and they sounded fine I honestly couldn't detect an audible difference between them and the polypropylenes. You can get the 100nF ones at rswww.com part number 414-7614 (18 pence each) or you can also get the same caps from White Noise.


 Have fun!


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_I used all metallized polyester in one of my WNA amps and they sounded fine I honestly couldn't detect an audible difference between them and the polypropylenes. You can get the 100nF ones at rswww.com part number 414-7614 (18 pence each) or you can also get the same caps from White Noise.
 Have fun!_

 

In the last moment I found some from Distrelec Austria http://www.distrelec.com/
 #821525 PHE 450 100 nF 250 VDC

 Before heating my soldering iron I wait for the Nichicon's and Black Gate's from Percyaudio


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_In the last moment I found some from Distrelec Austria http://www.distrelec.com/
 #821525 PHE 450 100 nF 250 VDC_

 

Ah, yes, they'll do the job nicely Fritz. So I take it you didn't buy the "full" kit from WNA? what did you get from them just the PCB?

 Mike.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Ah, yes, they'll do the job nicely Fritz. So I take it you didn't buy the "full" kit from WNA? what did you get from them just the PCB?
 Mike._

 

I ordered not a full WNA kit - without case, cap's and ALPS pot.


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_I ordered not a full WNA kit - without case, cap's and ALPS pot._

 


 Cool. Did you manage to source the current regulating diodes ok?

 Mike.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Cool. Did you manage to source the current regulating diodes ok?
 Mike._

 

As you mean that? David has marked the current regulating diodes and I have anothers from a wholesale importer as free samples.


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_As you mean that? David has marked the current regulating diodes and I have anothers from a wholesale importer as free samples._

 

Cool. They are really the only parts which may be tricky to find, the rest of the parts are pretty much available off the shelf. So......... when are you going to start putting her together Fritz?

 Mike.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Cool. They are really the only parts which may be tricky to find, the rest of the parts are pretty much available off the shelf. So......... when are you going to start putting her together Fritz?
 Mike._

 

I will make some fotos and publish it.

 OffTopic - your homepage are informative - I will buy the Roger Waters "In The Flesh" CD


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_I will make some fotos and publish it._

 

That would be great Fritz.

  Quote:


  Originally Posted by *FritzS* 
_OffTopic - your homepage are informative - I will buy the Roger Waters "In The Flesh" CD_

 

It's not a bad CD if you like Roger. I went to see him live in Manchester and, wow, what a great show!! another album you may like is Roger Waters "amused to death" not a bad recording and some good sound effects etc.

 Mike.


----------



## FritzS

Quote:


  Originally Posted by *FritzS* 
_I will make some fotos and publish it._

 

some questions 

 is this the right headphone jack for PCB





 in which nut shold the PCB bee - the first or the secound? Or in other word the distance between PCB and case - at the PCB side the distance between connector +V 0V -V (rail splitter) is very small





 inculded cables - I miss more lengh of the silver plated ptfe "green cable" - wherever should I connect the case with the ground of the amp?


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_some questions 

 is this the right headphone jack for PCB_

 

Yes and no. You have to snip the legs as shown to get it to fit on the board. I don't understand why David supplies this head socket with the PCB that has provision for a board mounted head socket...... unfortunately, this one is supplied and needs snipped so it can fit:







  Quote:


  Originally Posted by *FritzS* 
_in which nut shold the PCB bee - the first or the secound? Or in other word the distance between PCB and case - at the PCB side the distance between connector +V 0V -V (rail splitter) is very small_

 

Second or third slot. You can even hold the pcb in position with the volume control and headsocket nuts... there is no weight to the board so it's adequate to support it by the volco and headsocket.


  Quote:


  Originally Posted by *FritzS* 
_inculded cables - I miss more lengh of the silver plated ptfe "green cable" - wherever should I connect the case with the ground of the amp?_

 

Run a piece of wire from anywhere on the 0V track (ground) to the chassis. you can attach it to the chassis with a nut and bolt.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Yes and no. You have to snip the legs as shown to get it to fit on the board. I don't understand why David supplies this head socket with the PCB that has provision for a board mounted head socket......_

 

I favor your suggestion - David tells to the same question:
_The headphone jack is correct but its a bit of a story. Schurter do a pcb mounting version of the jack socket that I use but it's of lower quality than the solder tag version. So you cut the solder tags off flush with the body of the socket, then solder silver plated wires to the stubs of the solder tags, and fit these into the pcb - its all explained in the manual._

  Quote:


  Originally Posted by *PinkFloyd* 
_Second or third slot. You can even hold the pcb in position with the volume control and headsocket nuts... there is no weight to the board so it's adequate to support it by the volco and headsocket._

 

I have some other ideas - that I have a case without holes, I can modify the 
 position of the board.

  Quote:


  Originally Posted by *PinkFloyd* 
_Run a piece of wire from anywhere on the 0V track (ground) to the chassis. you can attach it to the chassis with a nut and bolt._

 

I will connect the 0V track (ground) to the chassis with a resistor, like 10 ... 100 Ohm and the case of the ALPS pot too.

 The Nichicon's and BlackGate's and some Holco resistors arrived 
	

	
	
		
		

		
		
	


	



http://www.stockhammer.at/hifi/wna.php

 The both input caps (4,7uF) I will replace with a 1 kOHM Holco resistor (possibly with a Murata Ferrite bead in serial). I will start with no 330 k so I can change easy between LM6171 and AD843.

 On output I will use the BlackGates in series with a 15 OHM Holco (for short circuit protection) but without Zobel at start.

 In future I will use second input jacks, one direct, one with the 4,7 uF caps.

 On the power input jack I will use a reverse 3 A diode in parallel - and a 35V zener diode in parallel to C7 for protection.

 One is hard to get here in Austria - silver coated isolated copper wire in less assemblage - import is expensive, so I pay'd 27 USD for shipping AND 21 EUR for customs duty and tax too - and this for 57 USD value of the product.

 "Prosit Neujahr!"


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_The headphone jack is correct but its a bit of a story. Schurter do a pcb mounting version of the jack socket that I use but it's of lower quality than the solder tag version. So you cut the solder tags off flush with the body of the socket, then solder silver plated wires to the stubs of the solder tags, and fit these into the pcb - its all explained in the manual.
_

 

It's easier to snip the tags as shown in the picture. This ensures a "perfect" fit with the head socket being flush with the PCB and saves farting about soldering six silver wires into position, hell what's the point of making provision for a potentiometer and head socket on the board and then supplying a head socket that doesn't fit.... sure you can solder wires onto the tags or cut the tags down but I'd prefer a head socket that was a perfect flush fit on the PCB... either that or make the darned holes on the PCB large enough to accommodate the gold plated head socket...... sorry but little things like this really annoy me, the whole idea of making provision for board mounted components is that the component will fit straight onto the board without having to customise it to fit. Rant over.


----------



## PinkFloyd

Looking good Fritz!


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_
 The both input caps (4,7uF) I will replace with a 1 kOHM Holco resistor (possibly with a Murata Ferrite bead in serial). I will start with no 330 k so I can change easy between LM6171 and AD843.
_

 

Just make sure if you remove the input caps that the DC offset remains at 0mV at "all" volume levels when running the LM6171... obviously you will have output caps in position?


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Just make sure if you remove the input caps that the DC offset remains at 0mV at "all" volume levels when running the LM6171... obviously you will have output caps in position?_

 

My Philips CD 650 have caps in in the output - I want to change them to Nichicon KZ soon.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_It's easier to snip the tags as shown in the picture. This ensures a "perfect" fit with the head socket being flush with the PCB and saves farting about soldering six silver wires into position, hell what's the point of making provision for a potentiometer and head socket on the board and then supplying a head socket that doesn't fit.... sure you can solder wires onto the tags or cut the tags down but I'd prefer a head socket that was a perfect flush fit on the PCB... either that or make the darned holes on the PCB large enough to accommodate the gold plated head socket...... sorry but little things like this really annoy me, the whole idea of making provision for board mounted components is that the component will fit straight onto the board without having to customise it to fit. Rant over._

 

I have done as you wrote but one of the tag I must cut off - it's not in line as the others - I put the silver wire extra, the hole are lare enough, and solder it above the PCB too
 My WNA works now - the first burn in test with my Senn HD 600 headphones - "WOW" its much more better than the headphone output of my Philips CD 650 or of the Yamaha CR 2040 receiver - both are "old HiFi classics". A complete test of hearing follows - with Eva Cassidy "Live At Blues Alley" and some other music all my hairs stand up, I have never heared this so before 
	

	
	
		
		

		
			




 First pics are here http://www.stockhammer.at/hifi/wna.php but my wna is not completely done


----------



## spendorspain

Hi all Head-Fiers and happy new year. 

 It's nice to see this forum re-energized by FritzS and Mike... Perhaps these quiet weeks we all have been listening to our WNA, simply enjoying our favorite music, but always it's possible to upgrade... or not: I've listening to the Linkwitz modified crossfeed and I dont't like it. It was very effective in giving more depth to the music but at the expense of reduced width and a general thickening of the sound, even in the low crossfeed setting. In some music with extreme L-R effects or an exaggerated treble perhaps the advantages outweigth these problems, but in classical music the vast majority of recordings have natural acoustic ambience enough. Or perhaps I'm used to listening to the headphone "cinemascope" perspective (however, I'll try the Meier natural crossfeed soon).

 I would recommend to FritzS to bypass the output capacitors C4. I'm currently using a 4.7 uF Evox and a 0.1 uF Wima FKP3 polypropylene film caps (the ones I had at hand), and the sound have improved over the BG Nx 1000uF alone. I'm going to order better bypass caps (a 5 or 10uF AmpOhm and a 0.1uF Mundorf Supreme or Silver in oil, installed in a new bigger case), but the cheap and easy bypassing I have now is well worth it. 

 I have a question about class-A operation in WNA headphone amp. According to several posts in this forum, I have to use a 100 ohm resistor in R6 position and a 160 ohm resistor in R5 (instead of the standard 75 and 121 ohm resistors) and add a little heatsink in each Tr1-4 transistors. However, I can't find an exact 160 ohm resistor, but only 158 or 162 ohm resistors. Which value is preferred, 162 or 158 ohm? Perhaps this is a critical value and the R5 and R6 values must have an exact relationship between them (I don't know). In any case, I don't like to order the wrong one and some help would be very appreciated.

 Best regards,
 Jose


----------



## PinkFloyd

Quote:


  Originally Posted by *spendorspain* 
_Hi all Head-Fiers and happy new year._

 

Happy New Year to you too 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *spendorspain* 
_I have a question about class-A operation in WNA headphone amp. According to several posts in this forum, I have to use a 100 ohm resistor in R6 position and a 160 ohm resistor in R5 (instead of the standard 75 and 121 ohm resistors) and add a little heatsink in each Tr1-4 transistors. However, I can't find an exact 160 ohm resistor, but only 158 or 162 ohm resistors. Which value is preferred, 162 or 158 ohm? Perhaps this is a critical value and the R5 and R6 values must have an exact relationship between them (I don't know). In any case, I don't like to order the wrong one and some help would be very appreciated._

 

Fitting a 100R and 160R will only increase the quiescent current by about 20%. The opamp is _*already*_ biased into class A and fitting 160R / 100R into R5 and R6 will only increase the quiescent current. If you do want to increase the quiescent current by 20% then you must fit adequate heatsinks to the transistors to dissipate the heat.... the values are not critical so you can have 160R / 100R +/- 10% As long as the values are the same per channel you don't have to strictly adhere to 160 / 100 you could go 145 / 90 140 / 85 etc. etc. to tailor the percentage of quiescent current increase. 160 / 100 gives a 20% (or thereabouts) increase in QC and I certainly wouldn't go much higher than 160 / 100... if you want 10% increase in QC then something like 140 / 90 should be about right (David will know the exact figures)


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_My WNA works now_

 

Nice one Fritz! It's a great feeling when they fire up first time isn't it? How did you find the build and the construction manual in general?

  Quote:


  Originally Posted by *FritzS* 
_the first burn in test with my Senn HD 600 headphones - "WOW" its much more better than the headphone output of my Philips CD 650 or of the Yamaha CR 2040 receiver - both are "old HiFi classics". A complete test of hearing follows - with Eva Cassidy "Live At Blues Alley" and some other music all my hairs stand up, I have never heared this so before 
	

	
	
		
		

		
		
	


	


_

 

Give it a couple of weeks for the caps etc. to form.... it gets better 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *FritzS* 
_First pics are here _

 

Looking great Fritz, nice website you've got there too.

 Mike.


----------



## FritzS

Happy new year to all Head-Fiers 
	

	
	
		
		

		
		
	


	



  Quote:


  Originally Posted by *spendorspain* 
_Hi all Head-Fiers and happy new year. 
 I would recommend to FritzS to bypass the output capacitors C4. I'm currently using a 4.7 uF Evox and a 0.1 uF Wima FKP3 polypropylene film caps (the ones I had at hand), and the sound have improved over the BG Nx 1000uF alone. I'm going to order better bypass caps (a 5 or 10uF AmpOhm and a 0.1uF Mundorf Supreme or Silver in oil, installed in a new bigger case), but the cheap and easy bypassing I have now is well worth it. _

 

This thought I have too, I have the both 4.7 uF Evox left over - I installed 1 kOHM instead of to eliminate the noise if you turn the potentiometer in CCW position, as reported in this thread - I use LM 6171 - for bypassing caps the ratio should be 1:10 ... 1:100
 please see here (all in german):
http://www.fl-electronic.de/modifika...ndensator.html
http://www.fl-electronic.de/modifika...ndensator2.jpg
 and http://www.audiomap.de/forum/ "Folien Bypass zu Elkos" Thema #17774

  Quote:


 I have a question about class-A operation in WNA headphone amp. According to several posts in this forum, I have to use a 100 ohm resistor in R6 position and a 160 ohm resistor in R5 (instead of the standard 75 and 121 ohm resistors) and add a little heatsink in each Tr1-4 transistors. However, I can't find an exact 160 ohm resistor, but only 158 or 162 ohm resistors. Which value is preferred, 162 or 158 ohm? Perhaps this is a critical value and the R5 and R6 values must have an exact relationship between them (I don't know). In any case, I don't like to order the wrong one and some help would be very appreciated.
 Best regards,
 Jose 
 

The use of little heatsink on each Tr1-4 are recommanded, they are hot in original kit - but which heatsink is small enough? I search for a clip-on (TO-126 / SOT32) typ - please tell me the manufacturer & typ.
 The 10 Ohm resistors are warm - the current on each are ~ 42 mA.
 The power on each Tr1-4 transistor I~42mA U~10V P~420mW


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Nice one Fritz! It's a great feeling when they fire up first time isn't it? How did you find the build and the construction manual in general?_

 

The manual should be a bit more detailed!
 For WNA MKIII - the place for caps should be larger, so I use RIFA PHE 450 0,1 uF / 250V the are "fatter" than the PHE 428 - here gives 5mm and 10mm RM types too!
 David use a thin twisted 3 pol. wire for power connect between rail splitter and each amp - I use the twisted (red/black) wire for +V -V and the green wire for ground (on bottom side of PCB) - and use the twisted (red/black) wire for output (P2 to Jack) on forefront of PCB.

 This parts I use:
 C5, C6 Nichicon FG 100 uF, 25V 
 C11, C12 Nichicon KZ 220 uF, 25V 
 C7 Nichicon KZ 220 uF, 50V
 C4 BlackGate NX 1000 uF 25V
 C2, C3, C8, C9, C10 Evox Rifa PHE 450 0,1 uF / 250V (follower of PHE 428)
 R11 instead of lamp - 15 OHM Holco H2
 instead of C1 - 1,02 kOHM Holco H4
 IC1, IC2 LM6171
 J2 ferrite

 Currently there is no ZOBEL net, no bypassing the electrolytics with small caps, no additional 330 kOHM feedback

 New pics are here: http://www.stockhammer.at/hifi/wna.php


----------



## FritzS

Quote:


  Originally Posted by *spendorspain* 
_Hi all Head-Fiers and happy new year. 
 I would recommend to FritzS to bypass the output capacitors C4. I'm currently using a 4.7 uF Evox and a 0.1 uF Wima FKP3 polypropylene film caps (the ones I had at hand), and the sound have improved over the BG Nx 1000uF alone. I'm going to order better bypass caps (a 5 or 10uF AmpOhm and a 0.1uF Mundorf Supreme or Silver in oil, installed in a new bigger case), but the cheap and easy bypassing I have now is well worth it. 
 Best regards, Jose_

 

Hi Jose - let know us the results!
 If the caps not go well together some resonances can occur - so the parasitic L (inductance) from the 1000 uF have a resonance with the bypass cap, if you use more different bypass caps, so on ... - please show:
http://www6.head-fi.org/forums/showp...&postcount=697
 The best way - to measure them!


----------



## 12796

All my emails to Dr White are getting bounced. Anyone else having this problem?


----------



## spacejay

Hello all

 New entrant here.

 I have just finished building the WNA mk II head amp with no previous experience at all in this sort of thing, so if anyone reading this is thinking of buying one, do it cause if I can do it you can do it.

 I did find soldering some of the smaller wires very fiddly and in fact, following my impatience to get the thing up and running wired a positive to a negative and blew some capacitors and op amps. Oops. Still, I learnt a lot.

 I have a stupid question as befits a total novice. I replaced the blown Rubycon with a 7 pence Jamicon from Maplin. David said I'd be advised to replace it with the Rubys but any advice on the best caps and what exactly do they do?

 Also any tweaks. I've only had it running a couple of hours so I gather the sound won't be "fully formed " for a while (I think I read somewhere 400 hours which seems a long time ).

 My only "criticism" is the LED which is the luminous equivalent of an H bomb going off.


----------



## StevieDvd

Welocome to the forums and Team WNA.

 Well done on your build - it's a better learning scenario when you fix things that can and do go wrong.

 I'm sure either Pinkfloyd or one of the more experienced WNA builders will jump in with loads of practical advice as they monitor WNA threads like hawks
	

	
	
		
		

		
		
	


	




 Steve


----------



## FritzS

Quote:


  Originally Posted by *spacejay* 
_I have a stupid question as befits a total novice. I replaced the blown Rubycon with a 7 pence Jamicon from Maplin. David said I'd be advised to replace it with the Rubys but any advice on the best caps and what exactly do they do?_

 

I use Nichicon from http://www.percyaudio.com/ - fore more please see here about http://www.stockhammer.at/hifi/wna.php
 Other good caps - Panasonic FM or FC

 Before power up - check up and check up and ......, then measuring and then carefully power up - I use a resistor 100 OHM, then 10 OHM in serial to the power line (from PSU to Anp) - and measuring - than power up and "fire" the headphone with music 
	

	
	
		
		

		
		
	


	




 - I use an old headphone before I use my Senn HD 600.


----------



## PinkFloyd

Quote:


  Originally Posted by *biovizier* 
_All my emails to Dr White are getting bounced. Anyone else having this problem?_

 

On and off, yes.


----------



## FritzS

Hi,
 has anyone tested - instead of the non-polar electrolytic caps- two polar 2000uF 25V electrolytics "face to face" (connecting with - pole) and put a resistor 81k to 10 kOHM) from this connection-point to V-
 So on each cap are ~ 10 V DC


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Hi,
 has anyone tested - instead of the non-polar electrolytic caps- two polar 2000uF 25V electrolytics "face to face" (connecting with - pole) and put a resistor 81k to 10 kOHM) from this connection-point to V-
 So on each cap are ~ 10 V DC_

 


 I tested this quite some time ago with 2 x electrolytics connected back to back but the sheer physical size is not practical and there really is no point doing this when non polar capacitors are available to buy.. sure, if you've got truckloads of room in the enclosure and you can't source non polar caps then there's no reason why you can't connect two electrolytics back to back to make a non polar cap. I haven't tried the resistor to V- this sounds like a good idea worth trying.


----------



## FritzS

Hi,
 I publish my hearing tests and tuning experience about the WNA and the CD 650 too on my homepage:
http://www.stockhammer.at/hifi/

 WNA http://www.stockhammer.at/hifi/wna.php
 CD 650 http://www.stockhammer.at/hifi/cd650.php
 About hearing please see both 
	

	
	
		
		

		
			





 PS: What cinch cables are use you? I use Nichicon KZ on output of the CD 650 - it is a very good cap in signal-line (if a lot of DC voltage stand on it), but it make problems with bad cinch cables! This combination sounds only good with good cables. The CD 650 use NE5532, but I will use AD OP275 (commended in an other forum).


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Hi,
 I publish my hearing tests and tuning experience about the WNA and the CD 650 too on my homepage:
http://www.stockhammer.at/hifi/

 WNA http://www.stockhammer.at/hifi/wna.php
 CD 650 http://www.stockhammer.at/hifi/cd650.php
 About hearing please see both 
	

	
	
		
		

		
		
	


	


_

 

Great site Fritz, keep up the good work, very informative indeed a real reference point for WNA owners 
	

	
	
		
		

		
		
	


	




 I'll be building up a balanced WNA very soon so there will be yet another reference point for this wondeful amp.

 [


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_ I'll be building up a balanced WNA very soon so there will be yet another reference point for this wondeful amp.
 [_

 

Next time I will write a list with all my ideas, improvements, suggestions, wishes about WNA MK III - and I have a lot of them


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Next time I will write a list with all my ideas, improvements, suggestions, wishes about WNA MK III - and I have a lot of them 
	

	
	
		
		

		
		
	


	


_

 

Go for it Fritz! The more suggestions and ideas the better, you can never have too much of a good thing... go for it man, the floor is yours......


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Go for it Fritz! The more suggestions and ideas the better, you can never have too much of a good thing... go for it man, the floor is yours......_

 

My first suggestions 
	

	
	
		
		

		
		
	


	




 Other output transistors:
 BD138/139 -> Toshiba 2SC2238 / 2SA968 or 2SA1837 / 2SC4793
 BD138/139 -> BD238/239

 C2/C3, C8/C9/C10 -> additional holes in PCB – it gives some caps with other lead distance … use 5 mm, 10 mm, 15 mm too

 C1 -> additional holes in PCB – it gives some caps with other lead distance … use 27,50 mm, 37,50 mm – for WIMA MKP 10 + additional holes for bypass caps – MKP, FKP use 5 mm, 10 mm, 15 mm

 C6 -> more place for Black Gates + additional holes for bypass caps!

 R11 -> place for a 1W resistor – additional holes ……

 Place around the electrolytic caps (fore “bigger” ones) + additional holes for bypass caps (extra PSU decoupling)!

 Use copper lines (with wire bridges) on PCB in place of the additional wiring – between output caps and headphone jack
 between rail-splitter and amplifiers
 between C1 and cinch connector – on PCB ….

 Headphone DC protection as supplement on PCB!?

 Additional input switch for more than one source + outgoing jack – to use WNA MKIII as preamp too!

 Zobel Filter – place on PCB (holes, solder -eye)

 Offset trim-potentiometer – place on PCB – likely for other OP’s too

 Schema for rail-splitter looks like as the amp ….. Class A too + option dual rail splitter

 330 kOHM tantalum place on PCB (holes, solder-eye) too

 Other mounting for headphone jack or other type ….

 Bigger case ....

 more about - in some days


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_My first suggestions 
	

	
	
		
		

		
		
	


	




 Other output transistors:
 BD138/139 -> Toshiba 2SC2238 / 2SA968 or 2SA1837 / 2SC4793
 BD138/139 -> BD238/239

 C2/C3, C8/C9/C10 -> additional holes in PCB – it gives some caps with other lead distance … use 5 mm, 10 mm, 15 mm too

 C1 -> additional holes in PCB – it gives some caps with other lead distance … use 27,50 mm, 37,50 mm – for WIMA MKP 10 + additional holes for bypass caps – MKP, FKP use 5 mm, 10 mm, 15 mm

 C6 -> more place for Black Gates + additional holes for bypass caps!

 R11 -> place for a 1W resistor – additional holes ……

 Place around the electrolytic caps (fore “bigger” ones) + additional holes for bypass caps (extra PSU decoupling)!

 Use copper lines (with wire bridges) on PCB in place of the additional wiring – between output caps and headphone jack
 between rail-splitter and amplifiers
 between C1 and cinch connector – on PCB ….

 Headphone DC protection as supplement on PCB!?

 Additional input switch for more than one source + outgoing jack – to use WNA MKIII as preamp too!

 Zobel Filter – place on PCB (holes, solder -eye)

 Offset trim-potentiometer – place on PCB – likely for other OP’s too

 Schema for rail-splitter looks like as the amp ….. Class A too + option dual rail splitter

 330 kOHM tantalum place on PCB (holes, solder-eye) too

 Other mounting for headphone jack or other type ….

 Bigger case ....

 more about - in some days 
	

	
	
		
		

		
		
	


	


_

 

So, in effect, a different amp!! I totally agree with you regarding the tracks for the rail splitter to amp, more room for bigger caps, bigger holes all round (especially to accomodate quality signal cables) a bit more space on the board, bigger board that will slot into a Hammond and a head socket that actually fits on the board or bigger holes for the headsocket.

 Mike.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_So, in effect, a different amp!! I totally agree with you regarding the tracks for the rail splitter to amp, more room for bigger caps, bigger holes all round (especially to accomodate quality signal cables) a bit more space on the board, bigger board that will slot into a Hammond and a head socket that actually fits on the board or bigger holes for the headsocket.

 Mike._

 

What think you about a modified buffer - looks like as 
http://www6.head-fi.org/forums/showp...9&postcount=18
 ..... transistors on place of the diodes?

 or the complete "diamond buffer"
http://www.elecdesign.com/Globals/Pl...tent/2800.html
http://www.elecdesign.com/globals/pl...mages/2801.gif

 one detail ist the current protection / current limiter - D3, D4, D5, D6

 For better ground - a dual layer PCB

 For the BD... Fischer Elektronik heat sink FK243 / FK 245

 if you have a evaluation board of a MK III I will test them


----------



## Algar

I've lost the psu that came with the kit. What should I get to replace it. Something not too expensive.


----------



## PinkFloyd

Quote:


  Originally Posted by *Algar* 
_I've lost the psu that came with the kit. What should I get to replace it. Something not too expensive._

 

One of these is compatible with the stock wallwart (12V type)


----------



## Algar

Quote:


  Originally Posted by *PinkFloyd* 
_One of these is compatible with the stock wallwart (12V type)_

 

You need to have a £500 order to get that outside England. But would just any 12v power adapter be good?


----------



## Alick

Quote:


  Originally Posted by *Algar* 
_You need to have a £500 order to get that outside England._

 

I suspect you meant outside the UK? They happily ship to Scotland, Wales and N. Ireland with no minimum order quantity, all of which are outside England.
  Quote:


 But would just any 12v power adapter be good? 
 

But yes, most 12VDC power supplies will work.


----------



## FritzS

What think about LT1364CN8, LT1365CN, LT082, LT084?


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_What think about LT1364CN8, LT1365CN, LT082, LT084?_

 

In what context Fritz?


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_In what context Fritz?_

 

It's a prinzipiell question - I read about LT082, LT084 in audioXpress (I have a subscription) and about LT1364CN8, LT1365CN in an german DIY forum.

 The LT1364CN8, LT1365CN family looks like those OP amps as we use in WNA.

 Today I use LM6171, but I have AD8065 and AD843 - but use you asymmetric current source diodes at all - so a little current runs to the output of the OP amp?

 PS: I read about "Suntan CD71 105c Non Polar output caps (sounded better than Nitai / Jamicon / Rubycon)" on your homepage - where I can get Suntan Non Polar caps?


----------



## Algar

I'll probably be getting this for a psu http://www.artesyn.com/media/pdfs/ssl20c.pdf


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_





 Mike._

 

Mike,
 whats the value from the PHE466 - bypass of the output electrolytic cap?

 What recommand you for bypassing a 1000 uF BG?


----------



## PinkFloyd

Quote:


  Originally Posted by *FritzS* 
_Mike,
 whats the value from the PHE466 - bypass of the output electrolytic cap?_

 

I think it was something like 100nF (polypropylene) and also a 1uF polyester in parallel with the output cap if I can remember correctly. 

  Quote:


  Originally Posted by *FritzS* 
_What recommand you for bypassing a 1000 uF BG?_

 

I really don't know Fritz, it's up to you, does it need "bypassing"? I don't use the blackgate caps as they're too big (physically) and way too pricey for what they are, you could try the 1UF / 100nF / 100pF combo made up of 1uF polyester, 100nF polyprop and 100pF silvered mica in parallel with it... your ears will know if it's right for you, just experiment until you hit that "sweet spot" In fact, why are you using output caps? Better if you fit a trimpot and lose those caps altogether. Of course you won't need them at all if you are using the AD8065 as the offset is minimal.

 Mike.


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_I really don't know Fritz, it's up to you, does it need "bypassing"? I don't use the blackgate caps as they're too big (physically) and way too pricey for what they are, you could try the 1UF / 100nF / 100pF combo made up of 1uF polyester, 100nF polyprop and 100pF silvered mica in parallel with it... your ears will know if it's right for you, just experiment until you hit that "sweet spot" In fact, why are you using output caps? _

 

1uF polyester ..... you are a polyester fan 
	

	
	
		
		

		
		
	


	



 I did not use input caps - so I use a output caps - it's only to protect my headphones from demand 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *PinkFloyd* 
_Better if you fit a trimpot and lose those caps altogether. Of course you won't need them at all if you are using the AD8065 as the offset is minimal._

 

I search for a small DC protection for the headphones - Davids kit is to big fore my case. If I have a DC protection I will cancle the output cap too


----------



## PinkFloyd

Wait a few days Fritz, there may be some news for you


----------



## FritzS

Hi,
 are good too!? I will get samples ..... 
	

	
	
		
		

		
		
	


	




http://www.linear.com/
 LT1363 - 70MHz, 1000V/µs Op Amp
 * 70MHz Gain-Bandwidth
 * 1000V/µs Slew Rate
 * 7.5mA Maximum Supply Current
 * 9nV/ rt Hz Input Noise Voltage
 * Unity Gain Stable
 * C-LoadTM Op Amp Drives All Capacitive Loads
 * 1.5mV Maximum Input Offset Voltage
 * 2µA Maximum Input Bias Current
 * 350nA Maximum Input Offset Current
 * 50mA Minimum Output Current
 * ±7.5V Minimum Output Swing into 150 ohms
 * 4.5V/mV Minimum DC Gain, RL=1k
 * 50ns Settling Time to 0.1%, 10V Step
 * 0.06% Differential Gain, AV=2, RL=150 ohms
 * 0.04° Differential Phase, AV=2, RL=150 ohms
 * Specified at ±2.5V, ±5V, and ±15V


----------



## 69CamaroSS396

Forgive me if this has been answered previously, but I haven't yet read all 37 pages of this thread. I can't access the White Noise website, either directly or through a link. I get what seems to be the home page, but I can go no further. Anyone else experience the same trouble?

 Thanks, Greg


----------



## FritzS

Quote:


  Originally Posted by *69CamaroSS396* 
_Forgive me if this has been answered previously, but I haven't yet read all 37 pages of this thread. I can't access the White Noise website, either directly or through a link. I get what seems to be the home page, but I can go no further. Anyone else experience the same trouble?_

 

here it works http://www.wnaudio.com/


----------



## PinkFloyd

Have you see the latest thread Fritz??


----------



## FritzS

Quote:


  Originally Posted by *PinkFloyd* 
_Have you see the latest thread Fritz??_

 

Yes I do


----------



## 69CamaroSS396

Quote:


  Originally Posted by *FritzS* 
_here it works http://www.wnaudio.com/_

 

Fritz, Thanks, but I have the same issue with that link. I see the page with the amps and the menu, and nothing happens beyond that. I've never had a problem like this.

 Greg


----------



## FritzS

Hi,
 The following modifications I will make ...... as seen on Walt Jung's Website ......
 WTnT_Op_Amp_Audio_2 - Realizing High Performance: Buffers (Part II) http://waltjung.org/PDFs/WTnT_Op_Amp_Audio_2.pdf
 Replace the two diodes with transistors - MPSA42 / MPSA92
 connect the collectors with a pice of wire to +V or to -V (as shown in picture)
 both resistors in path must be equal - 120 Ohm (Welwyn RC55C 0,25W 0,5%)
 both current sources must be equal - 3.5 mA
 ZOBEL network - 10 Ohm in series with a 100 nF cap (WIMA MKS4 0,1 uF 250VDC / Welwyn MFR4 0,25W 1%)
 a 15 Ohm resisitor in series to the headphone
 local and over all feedback resistors as described in some threads
 solder a 3 A reverse diode parallel to the PSU input posts und the PCB - to protect the amp from erroneous reverse polarity
 solder a Panasonic FC 2200uF 50V cap parallel to the PSU input jack

 If I have this done I will publish some photos here 
	

	
	
		
		

		
		
	


	








 The last ideas please see here:
http://www.stockhammer.at/hifi/wna.php

 PS: I see the PPA v2 with discrete buffers is similar to my suggestion (of WNA) but use more parts
http://elvencraft.com/ppav2/
http://laroccoaudio.net/discretebuffer.htm


----------



## FritzS

Dear All,
 really I miss the WNA discussions here 
	

	
	
		
		

		
		
	


	




 I hope a follower comes back as "phoenix out of ash" - as "Phoenix-HA1"!

 But no-one reply to my suggestion for modification.
 I think with an J-FET input OP and small modifications it can comes back as a great headphone amp!
 Another idea I have for the output DC protection - it's a symbiosis from some DIY projects. I will post this ASAP.

 My experience is a J-FET input OP sounds better than a bipolar input OP - AnalogDevice OP's sounds better than BurrBrown - the AD OP275 sounds better than NE5532N or OPA2134

 I hope for feedback


----------



## nph134

Sorry about that, the website had to be moved to a new server and there were some problems so for a few days only the homepage was there. The whole site is up now though.

 As it says on the front the website will stay up and show info on the up and coming WNA book.


  Quote:


  Originally Posted by *69CamaroSS396* 
_Fritz, Thanks, but I have the same issue with that link. I see the page with the amps and the menu, and nothing happens beyond that. I've never had a problem like this.

 Greg_


----------



## spendorspain

Hi

 Yesterday I've installed in my WNA MkII the modified AD744 op-amp, with the output stage bypassed (output taken from pin 5, not 6). The mod is very easy: solder in a 8-pin DIL socket a bridge between pins 5 and 6 and bend slightly the pin 6 of op-amp to avoid any contact with the socket (I've also isolated it with fine heatshrink). Thus, the output from op-amp pin 5 goes through the bridge to the socket pin 6, and the modified assembly can be used like any normal op-amp (see attached photos).

 Now the AD744 is in "IC1" position instead of LM6171 and the sound is very good, even with the output caps needed with LM6171 in place and with only 24 hour burning-in time. There is clearly more detail to my ears (my musical tastes are mostly classical symphonic) and without doubt it will improve as AD744 doesn't need any input/output cap in signal path. There is more space or air between instruments, so it is easier to hear the different musical lines or when two instruments are doubling. With AD744 it is like you sit a little further back in the concert hall (a perspective which I prefer with headphones) and the bass is much more tuneful and detailed.

 Using output caps, I've not yet measured the possible DC offset, but there is absolutely no thumps when powering on and off (with AD8065 there was a loud and frightening thump at turn-on and even more at turn-off).

 As listening goes on, I´ll post more impressions, but it looks very promising.

 Regards
 Jose


----------



## StevieDvd

The bypass option has been done on the Xin Supermacro and there's probable a list of opamps on Xin's forum which have the bypass (not all do).


 the next trick was to use both the bypass and to class A the opamp which needed a simple resistor bridge between 2 pins. Again only certain opamps were fit for this.


----------



## FritzS

Quote:


  Originally Posted by *StevieDvd* 
_the next trick was to use both the bypass and to class A the opamp which needed a simple resistor bridge between 2 pins. Again only certain opamps were fit for this._

 

You mean OP's as NE5534, SA5534, SE5534?

 Another way use a current source diode (1mA ... 2mA) between output and -V if this feature isn't integrated in the power stage (as in WNA MKII).


----------



## StevieDvd

Quote:


  Originally Posted by *FritzS* 
_You mean OP's as NE5534, SA5534, SE5534?

 Another way use a current source diode (1mA ... 2mA) between output and -V if this feature isn't integrated in the power stage (as in WNA MKII)._

 

yep as well as AD829, AD8021 & LT1115 when I eventually found the thread over at Xin's forum here

 Not sure about the diode option that's getting to techie for me and I have a mk1 WNA.

 I wonder just how many WNA amps are actually out there!

 Steve


----------



## AntiGeek

Hello 

 This is my first post so please forgive me for going off topic. I have just constructed a Super Cascode power supply for my WNA MK2 headphone amp and was just wondering how to best connect it up for maximum sound quality.

 I have tried to follow the printed construction manual however this left more questions unanswered that answered.

 As can be seen from the pics, i have tried to set up the PSU so both power output channels are connected in series.

 Basically my problem is that no matter what toroidal transformer secondaries I use (at the moment blue & yellow), quite abit of heat is emmitted from the output heatsinks and the AD843 chips. 

 Is this normal or is it something to do with the sensor lines (pretty much left a mystery in the manual) not being connected to the headphone amp??

 Sound quality through the headphone amp is vastly improved howvever I am really worried by this heat issue especially to the AD843 chips.

 I have scanned the Cascode Instruction manual & Headphone amps MK2 & MK3 onto word documents if anybody wants these.

 This is a great forum.

 Many thanks in advance for any help.


----------



## PinkFloyd

AD-843 runs warm / hot, Normal. BD139 / 140 run hot, Normal.

 You can dispense with those blackgate output caps, your amp will sound a lot better without them in the signal path. DC offset from the 843 should be <8mV so you're safe to remove them. Of course check the offset first.

 Mike.

  Quote:


 Sound quality through the headphone amp is vastly improved howvever I am really worried by this heat issue especially to the AD843 chips. 
 

This post may help you. Note I was running the amp with increased quiescent current so the temps were even higher.


----------



## AntiGeek

Hi Mike

 Many thanks for the swift response. Sorry for the confusion but I was actually referring to the AD843 and heatsinks in the Super Cascode PSU. I have not yet played around with the headphone amps OP amps (still stock LM6171s).

 I reckon both the AD843 chips and heatsinks in cascode are about 60c (they heat up in less than a couple of minutes from switch on).

 All the soldering appears OK and the thing does make the headphone amp sound a hell of a lot better.

 I know you have a built mk3 (I have yet to build mine though have got the pcb.)

 Unfortunely I don't have a test meter (the one I brought off Ebay was totalled!!). 

 Would you like to borrow the Super Cascode to test with your MK3 and check out how it sounds??

 I did ask doctor White about how to set up the Super Cascode and he sent me the below:

 "You use the 24V tappings on the transformer and configure the super csacode for independent 24V outputs. You only need to use one channel, leaving one spare. You still need to leave out one of the IC2 lm6171s on the MkIII headphone amp. Connect the P4s of each channel in parallel and then connect P4 +v to +v/+s on the cascode and P4 -v to -v/-s on the same cascode channel. You can't use one psu channel to power one headphone amp channel and the other psu channel to power the other headphone amp channel unless you have a system which is isolated dual mono throughout - usually difficult/impossible to arrange. The only other psu option is to use two super cascodes, one for each headphone amp channel, but bypassing the rail splitter/capacitance multipliers on the headphone amp pcb.
 I can still supply spares/components in cases of dire necessity.

 Regards, David"

 "Hi John,
 I misled you about using a super cascode with the MkIII headphone amplifier. I'd got so hung up on making sure that customers with the standard switch mode psu didn't blow up their headphone amps that I shut my mind to the other possibilities. If you use a cascode or super cascode psu configured to give two independent 24Vdc outputs then you can use each output to power one headphone amp channel separately via its P4 connector. In this case you need to insert LM6171s in both IC2 positions. I hooked up a system to check this out this afternoon. It works fine and makes a really worthwhile improvement - I heard small details on my test CD ( a Byrds compilation ) that I'd never heard before.

 Regards, David"

 Once again many thanks for your help and swift reply.

 John


----------



## PinkFloyd

Quote:


  Originally Posted by *AntiGeek* 
_Would you like to borrow the Super Cascode to test with your MK3 and check out how it sounds??_

 

Hi John,

 I really don't want anything to do with the super cascode or MKlll as they were rushed designs and I think David White is making up most of his answers to "build problems" as he goes along. The best person to contact would be David White _himself_

 First question is "why" are you using the 843 in the super cascode? is that the stock opamp for it? 60C sounds about right to me (for both the transistors and 843) and you'd be OK leaving them naked. You could, if you want, fit heatsinks and that would assist in dissipating any heat........ perfectly _normal_ for these components to get hot to the touch so don't worry about that John.

 All the best.

 Mike.


----------



## AntiGeek

Hello again Mike

 Yes the PSU comes stock with AD843s. Apparently they balance low noise with dynamics.

 Below is the explanation given:

 "The regulator error amplifier is an op-amp and the device chosen, the AD843, gives best all round performance. The AD825, on a surface mount to dil8 adaptor, performs equally well but is marginally less convenient to use. Lower noise can be achieved by using op-amps such as the AD797 or LT1028, whilst better dynamic performance can be had with the LM6171 or AD817. All nasties, such as noise and ripple, on the output of the Super Cascode power supply are at least l00dB down."

 Neither the Amp nor PSU has gone up in smoke so I assume they might be working ok. As far as heatsinks go, its abit of a tight fit as they will short if they come into contact. For the AD843s I May try getting and dremeling some of the chip heatsinks that computer overclockers use on their memory chips. When thermal pasted on they may improve heat dissipation a little.Maybe!!

 I agree with you about the MK3 being a rushed design though the Super Cascode seems like a fairly sound bit of design.

 Everything played through the headphone amp especially sax and female vocals really does sound far cleaner and like several veils have been removed from the performance. As the cascode has two totally separate channels, I may try feeding each channel direct into each of the P3s of the headphone amp.

 I may still build the MK3 when I can track down a supplier of all the welwyn resister values required.

 Is your new heed amp any better than the WNA mk1 & MK3??

 Many thanks for for your help.

 John.


----------



## FritzS

Quote:


  Originally Posted by *AntiGeek* 
_I may still build the MK3 when I can track down a supplier of all the welwyn resister values required._

 

Try http://www.farnellinone.com/ and 
http://www.rs-components.at/
http://www.rs-components.com/
 both have welwyn resistors

  Quote:


  Originally Posted by *AntiGeek* 
_Is your new heed amp any better than the WNA mk1 & MK3??_

 

I have MKII with AD843 now
http://www.stockhammer.eu/hifi/wna.php
http://www.blue-danube.at/

 My experience about AD843 please read here
http://rockgrotto.proboards39.com/in...ead=1146567048


----------



## FritzS

Hi,
 gives a new Super Cascode and WNA MKlll PCB source?
 David has closed his shop and did not answer 
	

	
	
		
		

		
		
	


	




 But some have schemas and photos about ......


----------



## PinkFloyd

Quote:


  Originally Posted by *AntiGeek* 
_Yes the PSU comes stock with AD843s. Apparently they balance low noise with dynamics._

 

Oh, he finally agrees with me that the 843 kicks the LM6171's arse then


----------



## AntiGeek

Hi Fritzs/Mike

Try http://www.farnellinone.com/ and 
http://www.rs-components.at/
http://www.rs-components.com/
 both have welwyn resistors

 Yes Fritzs, I have tried most of these +Maplins and Rapid.

 Can't seen to find 100ohm or 120ohm anywhere. Is there another make of resistor available which would do as good/better job?

Hi,
 gives a new Super Cascode and WNA MKlll PCB source?
 David has closed his shop and did not answer 

 But some have schemas and photos about 

 Unfortunetly/fortunetly not. I got my MK3 & Super Cascode shortly before Dr White closed up shop.

 If you need them, I can email you the construction manuals in word doc for both & realsize scans of both sides of the MK3 board.

Oh, he finally agrees with me that the 843 kicks the LM6171's arse then 

 Would it be worth trying these AD843s in place of the LM6171s in my mk2. Would the sound be noticebly improved especially with the removal of the blackGates??

 Many thanks for all your help

 John.


----------



## PinkFloyd

The resistors you want are 25 pence each. They are exactly the same as the Welwyn RC55Y.

 Most definitely worth trying the AD-843 and, yes, you can dispense with the output caps completely. You could swap the 843 that's in your PSU into the amp and the LM6171 that's in the amp into the PSU and give them a listen.

 I prefer the 843, I think Fritz likes it too?

 Over to you Fritz...................


----------



## FritzS

Quote:


  Originally Posted by *AntiGeek* 
_Hi Fritzs/Mike
Try http://www.farnellinone.com/ and 
http://www.rs-components.at/
http://www.rs-components.com/
 both have welwyn resistors
 Yes Fritzs, I have tried most of these +Maplins and Rapid.
 Can't seen to find 100ohm or 120ohm anywhere. Is there another make of resistor available which would do as good/better job?_

 

http://www.farnellinone.com/ 
 welwyn RC55C 0,25W 0.5% 
 9497978 100R RESISTOR, 0.25W 0.5% 
 9498079 121R RESISTOR, 0.25W 0.5%

 or Dale - but they are hard to get in Europe, till now I did not found - but some DIY's tells one of the Dale resistors familie are "superp audiophile high end"


----------



## AntiGeek

Mike/Fritzs

 Many thanks for the details on suitable resistor suppliers. Shall now be able to get on with my mk3 build.

 Shall leave testing AD843s until mk3 is built as I have rather stupidly soldered the lm6171s direct to the mk2 pcb. 

 Anyhow it leaves me with a nice build project to get stuck into.!!

 Regards

 John


----------



## PinkFloyd

You'll notice the rapid ones are 0.1% and not 0.5%


----------



## 12796

I preferred both the ad847 and the ad8065 to the ad843 - though all were better than the lm6171 - in the head amp at least. I only have the WNA headamp left now.


----------



## ciuffoly

Look this new project on:

http://www.audiodesignguide.com/DAC_final/DacFinal.html

 see end of web page


----------



## FritzS

Quote:


  Originally Posted by *biovizier* /img/forum/go_quote.gif 
_I preferred both the ad847 and the ad8065 to the ad843 - though all were better than the lm6171 - in the head amp at least. I only have the WNA headamp left now._

 

Now I found the LME49710 (single version from LM4562)

http://www.national.com/pf/LM/LME49710.html
http://cache.national.com/ds/LM/LME49710.pdf

 and ordered some LME49710 to test them in WNA MKII 
	

	
	
		
		

		
		
	


	




 It's a exciting game LME49710 and LM4562 vs. AD843, OP275, AD823, ect


----------



## FritzS

Quote:


  Originally Posted by *FritzS* /img/forum/go_quote.gif 
_Now I found the LME49710 (single version from LM4562)
http://www.national.com/pf/LM/LME49710.html
http://cache.national.com/ds/LM/LME49710.pdf
 and ordered some LME49710 to test them in WNA MKII 
	

	
	
		
		

		
		
	


	



 It's a exciting game LME49710 and LM4562 vs. AD843, OP275, AD823, ect 
	

	
	
		
		

		
		
	


	


_

 

Hi,
 now I use three LME49710 in WNA MKII in my modified WNA MKII, instead of AD843 (amp) / LM6171 (railsplitter).
 First I cannot hear any difference between. First I heared with senn HD 600.

 I think for exact compare I must use two WNA's so I can change very quick between to hear very small differences 
	

	
	
		
		

		
		
	


	




 Some of CD/SACD's I used:
 KODO (Japan SONY), Concord Jazz SACD sampler, PF Final Cut, ....


----------



## FritzS

Quote:


  Originally Posted by *FritzS* /img/forum/go_quote.gif 
_Hi,
 now I use three LME49710 in WNA MKII in my modified WNA MKII, instead of AD843 (amp) / LM6171 (railsplitter).
 First I cannot hear any difference between. First I heared with senn HD 600.

 I think for exact compare I must use two WNA's so I can change very quick between to hear very small differences 
	

	
	
		
		

		
		
	


	




 Some of CD/SACD's I used:
 KODO (Japan SONY), Concord Jazz SACD sampler, PF Final Cut, ...._

 

Hi,
 now I am going back to AD843 (amp) / LM6171 (railsplitter)

 It's imagination from me or not - with LME49710 and K 701 I feel the trap is littleness sharper .........
 music SACD Ray Brown - Summer Wind - Live At The Loa 
	

	
	
		
		

		
		
	


	




 I test the AD843 in railsplitter - it oscillates


----------



## FritzS

Quote:


  Originally Posted by *FritzS* /img/forum/go_quote.gif 
_Hi,
 now I am going back to AD843 (amp) / LM6171 (railsplitter)

 It's imagination from me or not - with LME49710 and K 701 I feel the trap is littleness sharper .........
 music SACD Ray Brown - Summer Wind - Live At The Loa 
	

	
	
		
		

		
		
	


	




 I test the AD843 in railsplitter - it oscillates 
	

	
	
		
		

		
		
	


	


_

 

Hi,,
 now I run two AD847 in my modified WNA MKII (with AKG K701 and Marantz SA 7001 KI)

 My first experience:
 More punch
 More "metal" than "soft" in "brass"
 Music come to the fore
 Not for quiet sound level - here is the AD843 "king"

 My opinion - this statements are subjektiv - objective are only ABX tests with two similar amps but different OPA's and a ABX switcher.
 But this statement is be true for the most of the DIY test's ..... or? 
	

	
	
		
		

		
		
	


	




 Has anyone test the AD847 (singel) or AD827 (dual) too?


----------



## FritzS

We ignore Linear Technology Linear Technology - Linear Home Page 

 Now I use two LT1056 in place of the both AD847
 There are very little differences ....

 First test - from the first tick I hear - I am snoopy why after a burning in time 
 Treble (cymbals) are a little bit softer, silkier, darker, more natural
 Micro Dynamics - more than AD847 - more in background too.

 2nd & 3rd test - as far as I can see the LT1056 is a "big player" like AD843 too 
	

	
	
		
		

		
		
	


	




 Natural, detailled sound with good micro dynamics, open wide and deep stage.

 I think one must be changed: The WNA design use a ferrite bead between the output of the OPA and the powerstage. This is not calculated for other OPA's. The datasheet suggestions of LT1056 use a little cap 10 ... 33 pF in NFB:

 "When the feedback around the op amp is resistive (RF), a
 pole will be created with RF, the source resistance and
 capacitance (RS, CS), and the amplifier input capacitance
 (CIN ≈ 4pF). In low closed-loop gain configurations and
 with RS and RF in the kilohm range, this pole can create
 excess phase shift and even oscillation. A small capacitor
 (CF) in parallel with RF eliminates this problem. With RS
 (CS + CIN) = RFCF, the effect of the feedback pole is
 completely removed."

 But I dont hear oscillation in audible range or distortion. Only very good sound 
	

	
	
		
		

		
		
	


	
















 And all this with an "old design" 5.5 MHz, 14V/us OP - silmilar to the OPA602 
	

	
	
		
		

		
		
	


	




 Next I will test LT1022 if I get some samples 
	

	
	
		
		

		
		
	


	




 Speed are not essential 
	

	
	
		
		

		
		
	


	



 Gain Bandwidth / Slew Rate
 LT1056 5.5MHz 14V/us
 LT1022 8.5MHz 23V/us
 OPA602 6.5MHz 35V/us
 AD847 50 MHz 300V/us
 AD845 16 MHz 100V/us
 AD843 34 MHz 250V/us
 LM6171 100MHz 3600V/us
 AD817AN 50 MHz 350V/us


----------



## FritzS

I want to use my WNA MKII on a second place in my house - with the old Philips CD650 too.
 Headphone is the 25 Ohm impedance Denon AH D7000

 Last testing OPA was the LME49710NA - it plays very good - but I am not totally happy with it. 

 So I searched further, after the LME49710NA I put in ...

 OPA134 similar, but a bit more musically than the LME49710NA
 OPA604 similar to the OPA134, but a bit more muted
 LM6171 that's is - very detailed, more punch, the D7000 likes the LM6171 in the WNA MKII

 My special mods in the WNA you found here
blue-danube DIY audio - WNA MKII Modifications

 I hear music if I write this text - the longer, the better the music are played, the WNA and CD640 burning in - they had a longer time out before 

 Music:
 Audio - Digital Masters I / Sara K. + some Chesky & Telarc (Classic) samplers
Audio, das Magazin fÃ¼r Hifi, High End, Surround und Musik - AUDIO 01/10

 The Klezmatics - Live in Berlin
The Klezmatics - Grammy Award Winning Music

 Neil Diamond - Jonathan Livingston Seagull
 Paul Simon - Graceland

 PS: My opinion - this statements are subjektiv - objective are only ABX tests with two similar amps but different OPA's and a ABX switcher.
 But this statement is be true for the most of the DIY test's ..... or?


----------



## FritzS

[size=x-small]Hi,
 before I put my WNA MKII into my depot, I changed the OPA's
 before AD847, and now OPA134 ..... and wow it tops my "green" Solo with OPA LME49720HA instead of the AD823.

 It's only an imagination? [/size]
	

	
	
		
		

		
		
	


	




 [size=x-small]The WNA MKII sounds a bit more naturally, warmer
 Solo inclines sometimes to a little bit sharp tails ...

 The WNA MKII source impedance: 15 OHM (series resistor in the output)
 Solo use 33 OHM

 Tested with my AKG Q701 (I know some prefer 120 OHM as source impedance with this headphone)[/size]
   
  [size=x-small]The next step are[/size]
  [size=x-small]now with OPA627 .. and the violins shines ....[/size]
  [size=x-small]and my Denon AH D 7000 like it too [/size]
	

	
	
		
		

		
		
	


	




 [size=x-small]Max Bruch, Violinkonzerte Nr. 1 & 2, Salavatore Accardo, Gewandhausorchster Leipzig, Kurt Masur, CD
 Max Bruch, Violinkonzerte Nr. 1 & 3, Tortsen Janicke, Gürzenich Orchester, Markus Stenz, SACD

 and the both BlackGates NX 1000 uF 25V are re-burned in now (the sigle caps in signal path) [/size]
   
  more about
http://rockgrotto.proboards.com/index.cgi?board=m&action=display&thread=8052

 [size=x-small]PS: For two month I had an AKG K1000 as guest - now I must then give back - the K1000 is an very gread headphone! [/size]


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## 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.
 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/


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## FritzS

Now I test *AD797* opamps (biased into class-A as all others in this place). They are different to *OPA627* and offers a bit more fine details and less sharpness with *AKG K812 Pro* (in some music tracks hearable).
I had thought about oscillation before without compensation of *AD797*. But it works well without additional caps. *AD797* have a bit of a diva.

*AD797* now the best OPA in *WNA MKII*.


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## FritzS (Oct 1, 2021)

After *AD797* I returned to *OPA134* with good result.
BUT  - now I use a pair of *Burson V6 Vivid *single.
The best sound I had ever heard with (now old) WNA MKII!
My first impression, very detailed, yet musical, no noticeable sibilants, airy, space between musicians, very detailed, good micro dynamic, relaxed listening with the AKG K812.
Music: PinkFloyd - The Final Cut; Loreena McKennitt - Live at the Royal Albert Hall.
The playback chain is now fully discrete, Marantz also uses discrete amplifiers in the analog section of the SA 7001 KI CD/SACD player.


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## n7rak

Any idea where I can purchase a WNA Mk2 board or kit? Thanks in advance.

Rick


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