# "White Noise Head amp kit"



## PinkFloyd

[size=xx-large]Latest[/size]

 To save any new people having to trawl through over 600 posts the WNA is now supplied as a complete kit for £150.. details here the kit includes everything you need to build the complete amp and even comes with a PSU... it uses top quality parts and is the best amp I have heard. For those of you who want to find out the history of how the amp has evolved and improved over the past year then start here: 


 I've today taken delivery of the White Noise Audio (WNA) headphone amp kit after threatening to try it out for the past couple of years.

 As you'll probably know, I've spent the past 2 years tinkering with the Chiarra and assisting Graham Slee with the mods to his "SOLO" amp and haven't had much time to dedicate to anything else (amp wise)

 I was first made aware of the WNAHA (white noise audio head amp) a couple of years back and always meant to give it a try but never seemed to get round to it..... It's another one of those "unchartered territory" amps, like the Chiarra was at the time, and to spend money on the kit is something of a gamble as there's not a lot of information about it on the web and, as such, I was reluctant to give it a go.

 Well, life is too short to "wonder" and I've taken the first step and purchased a kit and will be reviewing the completed amp in due course. I have spoken with the designer, David White, and am impressed with his philosophy and his electronics knowledge and his design.

 Full details of the WNAHA kit can be viewed at http://www.wnaudio.com/cat.pdf (page 17)

 The WNAHA "appears" good on paper and the PCB slots directly into a Hammond but will it be able to compete with a Chiarra or a PPA? All will be revealed shortly.

 I'll poplulate the board next week sometime and will report back, in full, with my findings once the amp has had a chance to break in.

 In the meantime............ a sneak preview of a 5% populated WNAHA in a Hammond enclosure........... imagine it fully populated with Stepped attenuator and OPA 627 etc........... looking good.












 Pinkie.


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## damitamit

Looks interesting. did you get the audiophile or standard kit?

 I look forward to your review...


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## Nigel

Nice one Pinkie!

 I don't recall seeing this amp mentioned on Head-Fi before. It will be interesting to read your impressions.


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## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_Looks interesting. did you get the audiophile or standard kit?

 I look forward to your review..._

 

I just bought the PCB, 4 constant current diodes, 2 x 12V 60mA wire ended incandescent lamps and a gold plated headphone socket from WNA.

 I'd probably have been as well ordering the complete kit from WNA as it took me like 3 hours to source the parts from Rapid electronics / maplins etc. I managed to get everything though and am just waiting for it all to arrive 
	

	
	
		
		

		
		
	


	




 Also going to order one of WNA's stepped attenuators as the conductive plastic pot I was going to get from RS components was out of stock (bloody typical!) I've never used a stepped attenuator before so it will interesting to see how it performs in relation to a carbon pot.

 Pinkie.


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## buggalugs

Been using one for some time now. It's a satisfactory piece of kit which I'm happy to live with but I won't steal PF's thunder.... I might follow up his review with a few comments at a later time.


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## PinkFloyd

Quote:


  Originally Posted by *buggalugs* 
_Been using one for some time now. It's a satisfactory piece of kit which I'm happy to live with but I won't steal PF's thunder.... I might follow up his review with a few comments at a later time._

 

Feel free to steal my thunder Buggalugs, it'll save me a lot of typing 
	

	
	
		
		

		
		
	


	





 What op amps are you using, are you using a stepped attenuator and what do you mean it's a "satisfactory piece of kit"? does that mean "it does the job" or "it does the job and then some" or "It's ok but nothing special" etc. etc. ?

 The instructions are great up to a point but omit to tell you where to connect the potentiometer on the board........ did you find this also or am I just being thick?


 All the best.



 Pinkie.


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## buggalugs

Yes I'd better clarify what I meant by the word satisfactory - firstly this amp bears a marked similarity to a circuit from the UK magazine Elektor published about a dozen or so years ago so I would't say it's at the cutting edge of current thinking. It is an ultra simple circuit buffered with a complimentary pair of transistors (the ubiquitous BD139/140) contained within the feedback loop of the opamp and biased into class A with constant current diodes. No attempt is made to bias the opamp into class A, which Dr. White considers more trouble than it's worth.
 Nonetheless those of us who have made headphone amps over the years may have found that less is often more in terms of quality and therein lies the strength of this amp. It is very direct, clear and dynamic. I have slight reservations about the overall quality of reproduction which IMHO slightly hardens up when the source material becomes complex and loud. Others may not notice this ( I am being hyper critical).
 This is why I was hesitant about going over the top with my initial response. However if I applied a personal subjective scale for amps I have currently on hand for comparison I would put (out of 10) the headphone socket of my main amp on 4, my CMOY on 5, my maxed out Meta 42 on 6.5 and the White amp on 8.5.
 Dr White himself feels marginal improvement would be gained by using a darlington pair of transistors in the output stage to improve linearity; pity he's not thinking Mosfet!
 One thing I really do like about the circuitry is the very elegant on-board rail splitter which is quite unlike anything I have seem in these forums. It really does supply an ultra clean and really "stiff" supply making all the battery amps I have on hand sound thin and wimpy.
 When I built this amp I didn't use input caps (never do in fact - if you need them then your source must be suspect in my view). I soon removed the lamp bulbs used as output protection and gained another half octave of bass extension as a result (I substituted them with 4.7r resistors and I make sure that the phones are not plugged/unplugged when the amp is switched on to avoid transient short circuits). 
 Regarding op amps I like the AD8610 better than OPA627 and this is my current choice. I find the OPA627 sounds like an old man mumbling into his beard compared with the startling definition and clarity and detail rendition of the AD8610.... a real champagne quality with this device. Of course the opamp is everything with this type of circuitry - as it will be with the Chiarra.
 Pink Floyd - you mention that there is no space on the board to mount the pot or attenuator. I'm afraid that's correct - you'll have to mount it separately and wire it up with flying leads which is a bit of a pain. In fact you may have trouble shoehorning all this lot into the enclosure you picture so good luck mate!
 Do make it up and post one of your inimitable reviews - I'm absolutely sure you'll be impressed by it.


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## PinkFloyd

Hi Buggalugs,

 You were right! a shoehorn is required to get everything into this enclosure 
	

	
	
		
		

		
		
	


	




 I've managed to work round the headphone socket and will fit C2 underneath the board (plenty of room) I fitted the LED and bezel (being replaced with a blue one. that red thing looks like a big cherry!) directly above the headphone socket to give me more room on the front panel for a biggish volume control knob.

 Unfortunately, my plan for a stepped attenuator won't be going ahead as there's definitely not enough room (see pic)






 As you can see C4 and C6 (not yet fitted) would get in the way. as would the transistor and electrolytics  I've been hunting about for a suitable alternative and have only managed to find a Spectrol 12mm conductive plastic pot at £6.08. It's a "linear" pot and I'm wondering if I'd be better hunting for a log variety? David white reckons 10K is the way to go...... to be on the safe side would 20K be ok? Are you using a stepped attenuator in yours?

 All I have to do now is to source a decent pot, fit all the caps, fit heatsinks onto the transistors and wire the amp up (that'll be fun!)

 Oh well, that's the state of play so far and I should get round to completing it by the end of the week with a bit of luck. It's a pity the stepped attenuator wouldn't fit into the enclosure but I think I'd prefer a conductive plastic pot in a compact enclosure rather than a stepped attenuator in a big ugly behemoth of an enclosure 
	

	
	
		
		

		
		
	


	




 Here are a few pics of the progress so far (about 2 hours work)

 By the way, do you have any pics of yours? It would be great to have a look at the wiring as there are no instructions in the manual on where to connect the pot to 
	

	
	
		
		

		
		
	


	




 I assumed there would have been provision made on the PCB (ie 6 pads) for the potentiometer connection but obviously not 
	

	
	
		
		

		
		
	


	




 I'm sure it's "figureoutable" but that's definitely a very weak part of the instructions and a diagram showing the pot connections would have been very welcome. Apart from that, the instructions are superb.


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## buggalugs

Hiya Pink. I used the next size up Hammond case from the one you have which made assembly a whole easier. 
 Regarding pots I'm using a 47k alps pot merely 'cos I had one available in my box of spares; I'm no expert on these things but intuitively I feel 10k or 22k one would be a slightly better choice. I quite fancy the stepped attenuator option and may go down this route at some stage. Just on this matter of pots I have a 100k pot extracted from a previous (thermionic) project which cost me over £40 from Audionote about 10 years ago; this very expensive pot (purportedly the bees knees at that time) measures OK at minimum setting but after a 10% turn measures 111k in one channel and 96k in the other! What a stitch up!
 By the way Rapid electronics in the UK were showing Alps pots available at 6 quid apiece and in stock until recently.
 I wonder - are you going to use your Andante supply for this amp? - it should do the trick well. Funnily enough I have a very early Andante power supply here myself which is gathering dust in my attic but since I have a marked preference for the AD8610 it pushes out just a bit too much voltage for that chip, so I use the excellent 24v wallwart sourced from David and duly populated the rail splitter section on the board. 
 If you use a + 15v - 15v supply David recommends that heat sinks are required for the output transistors; I'd suggest you don't get those clip on sinks from Maplin which are crap and tend to fall off but merely bolt on some small pieces of aluminium sheet which will be entirely adequate.
 One other observation - David bangs on on his web site about the benefits of gold plated input/output connecters but what does he supply with his kit to couple up the signals? - nothing less than risible little tin plated plugs and sockets. I gained a vast improvement in sound quality by hard wiring my cabling directly to the pins and omitting the plugs.
 I've just moved house and haven't got round to unpacking my digital camera; when the dust/blood pressure settles I'll try and get round to supplyling some pics.


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## buggalugs

Just re read your post Pink. Don't even think of buying a linear pot unless you want to ponce around with law faking resitors or shunt resistors... I should know since I wasted many an hour trying to optimise the values for these!


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## PinkFloyd

Quote:


  Originally Posted by *buggalugs* 
_Hiya Pink. I used the next size up Hammond case from the one you have which made assembly a whole easier. 
 Regarding pots I'm using a 47k alps pot merely 'cos I had one available in my box of spares; I'm no expert on these things but intuitively I feel 10k or 22k one would be a slightly better choice. I quite fancy the stepped attenuator option and may go down this route at some stage. Just on this matter of pots I have a 100k pot extracted from a previous (thermionic) project which cost me over £40 from Audionote about 10 years ago; this very expensive pot (purportedly the bees knees at that time) measures OK at minimum setting but after a 10% turn measures 111k in one channel and 96k in the other! What a stitch up!
 By the way Rapid electronics in the UK were showing Alps pots available at 6 quid apiece and in stock until recently.
 I wonder - are you going to use your Andante supply for this amp? - it should do the trick well. Funnily enough I have a very early Andante power supply here myself which is gathering dust in my attic but since I have a marked preference for the AD8610 it pushes out just a bit too much voltage for that chip, so I use the excellent 24v wallwart sourced from David and duly populated the rail splitter section on the board. 
 If you use a + 15v - 15v supply David recommends that heat sinks are required for the output transistors; I'd suggest you don't get those clip on sinks from Maplin which are crap and tend to fall off but merely bolt on some small pieces of aluminium sheet which will be entirely adequate.
 One other observation - David bangs on on his web site about the benefits of gold plated input/output connecters but what does he supply with his kit to couple up the signals? - nothing less than risible little tin plated plugs and sockets. I gained a vast improvement in sound quality by hard wiring my cabling directly to the pins and omitting the plugs.
 I've just moved house and haven't got round to unpacking my digital camera; when the dust/blood pressure settles I'll try and get round to supplyling some pics._

 

Hi Bug,

 I'm starting off by putting a kinda basic kit together first to see what it sounds like and will report firstly and foremost on the standard amp. I'll start with OPA134 opamps then go to OPA 627, AD8610 etc etc. It's only fair for other DIY'ers to learn about the standard kit first and, if there are improvements that can be introduced further down the line then all the better. I've got all the Burr Brown and Analogue devices chips that can possibly drop into the WNAHA at hand and will experiment over the next year or so 

 My "major" concern at the moment is with the instructions (or lack of) regarding connection of the headphone socket and the potentiometer. I expect clear instructions from start to finish and the provider of the kit should (at no stage) assume the builder knows / understands what's required... builders of kits range from the absolute beginner to the very experienced and the instructions should cater for the absolute beginner as well as the seasoned pro's.

 I've brought this to David's attention and he'll hopefully address the issue in the immediate future......... I won't connect the headphone socket and pot up until he sends a diagram in case I short circuit something 
	

	
	
		
		

		
		
	


	




 Pinkie.


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## guzzler

Pinky, Rapid Electronics sell the ALPS Blue, it's order code 66-0225 for the 50K version, at £8.50

 g


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## PinkFloyd

Quote:


  Originally Posted by *guzzler* 
_Pinky, Rapid Electronics sell the ALPS Blue, it's order code 66-0225 for the 50K version, at £8.50

 g_

 

Hi G


 I know.......... it's too big for the enclosure  Thanks for the steer toward rapid btw.......... fantastic firm 
	

	
	
		
		

		
		
	


	




 Mike. looking fo a 12mm conductive plastic pot........ dual log 50K preferably


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## Nisbeth

No conductive plastic, but anyway:

 1) Farnell has a 9mm Alps dual that should fit just fine. Quality is OK without being outstanding in any way
	

	
	
		
		

		
		
	


	




 Some claim that they track horribly but I haven't had any problems with the ones I've used (just a few, but still)

 2) Guzzler might still be hiding a few Panasonic EVJ's somewhere 
	

	
	
		
		

		
		
	


	




 The quality is a bit better than the Alps and it should fit as well. The only problem is that it is difficult to work with if you want to solder wires directly onto the legs 
	

	
	
		
		

		
		
	


	




 /U.


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## PinkFloyd

Quote:


  Originally Posted by *Nisbeth* 
_No conductive plastic, but anyway:

 1) Farnell has a 9mm Alps dual that should fit just fine. Quality is OK without being outstanding in any way
	

	
	
		
		

		
		
	


	




 Some claim that they track horribly but I haven't had any problems with the ones I've used (just a few, but still)

 2) Guzzler might still be hiding a few Panasonic EVJ's somewhere 
	

	
	
		
		

		
		
	


	




 The quality is a bit better than the Alps and it should fit as well. The only problem is that it is difficult to work with if you want to solder wires directly onto the legs 
	

	
	
		
		

		
		
	


	




 /U._

 

I've found a superb Bournes pot which Dr. White recommended (silky smooth and the business) I'll reveal All soon (as if!)

 Pinkie.............


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## bpribadi

Hi Pinky, I saw the gold plated headphone socket used on your casing. I have the same socket I ordered from Farnell, but when I received it, it doesn't fit the normal 3.5 mm headphone jack. The normal headphone jack is too short for the socket, so when pluged in, the ground and the right channel (middle contact of the jack) is shorted, and the jack's tip only reach the 2nd contact of the socket. I expect the tip should reach the last contact.

 How about yours? Does it fit a normal 3.5mm headphone jack?


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## PinkFloyd

Quote:


  Originally Posted by *bpribadi* 
_Hi Pinky, I saw the gold plated headphone socket used on your casing. I have the same socket I ordered from Farnell, but when I received it, it doesn't fit the normal 3.5 mm headphone jack. The normal headphone jack is too short for the socket, so when pluged in, the ground and the right channel (middle contact of the jack) is shorted, and the jack's tip only reach the 2nd contact of the socket. I expect the tip should reach the last contact.

 How about yours? Does it fit a normal 3.5mm headphone jack?_

 

The one I have is a 6.3mm socket and the 6.3mm jack plug fits into it perfectly. Have you got a link to the socket you bought?

 All the best.

 Mike.


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## PinkFloyd

Quote:


  Originally Posted by *buggalugs* 
_I soon removed the lamp bulbs used as output protection and gained another half octave of bass extension as a result (I substituted them with 4.7r resistors and I make sure that the phones are not plugged/unplugged when the amp is switched on to avoid transient short circuits). _

 

Yes, I'm not too keen on the lamps myself. I measured their resistance with 4 independant meters (to be sure I got an average reading) and here is what they measured:

 21.7 ohm
 21.2 ohm
 21.9 ohm
 21.3 ohm

 So, if I substitute the incandescent lamps with a 22 ohm 0.1% 15ppm/C resistor we should be rocking ?


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## PinkFloyd

Quote:


  Originally Posted by *buggalugs* 
_I wonder - are you going to use your Andante supply for this amp? - it should do the trick well._

 

No, I'll either use the superb £7.95 regulated PSU from http://www.rapidelectronics.co.uk/rk...2001&XPAGENO=1 or I'll use the Graham slee PSU1 (24V) 

  Quote:


  Originally Posted by *buggalugs* 
_One other observation - David bangs on on his web site about the benefits of gold plated input/output connecters but what does he supply with his kit to couple up the signals? - nothing less than risible little tin plated plugs and sockets. I gained a vast improvement in sound quality by hard wiring my cabling directly to the pins and omitting the plugs._

 

I prefer to hard wire to the board also.......... I found the large section of
 the manual relating to "latching pins and plugs" a tad convoluted and that section could have concentrated on how to connect the darned amp up to the headphone sockets / pot etc etc........ to heck with "latching pins" 
	

	
	
		
		

		
		
	


	







  Quote:


  Originally Posted by *buggalugs* 
_ I've just moved house and haven't got round to unpacking my digital camera; when the dust/blood pressure settles I'll try and get round to supplyling some pics._

 

Don't "try" make a point of doing it... nothing quite beats amp pRon


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## PinkFloyd

Phew! Things sure are getting tight inside the enclosure with, literally, 1 millimetre to spare in places 
	

	
	
		
		

		
		
	


	




 I've still got to fit the 3 x 100nF polyprop caps (waiting for them to arrive) and then it's a case of wiring everything up and (all being well) listen to the amp!

 I decided to go for a Bourns 91A2A-B28-D15 10K Log potentiometer and, fortunately, it's a perfect fit 
	

	
	
		
		

		
		
	


	




 I've also replaced the Red LED with a blue LED so that should dress the front panel a bit better.


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## bpribadi

Beautiful! Very neat indeed!

 I'll get one of those Hammond 4511 series for my next project.

 May I know what potensiometer you use in the box?


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## PinkFloyd

Quote:


  Originally Posted by *bpribadi* 
_Beautiful! Very neat indeed!

 I'll get one of those Hammond 4511 series for my next project.

 May I know what potensiometer you use in the box?_

 


 The potentiometer is a 10k dual log Bourns 91A2A series which is apparantly a very good pot indeed. I haven't hooked it up yet but it's certainly got a silky smooth action and feels a lot better than the ALPS blue velvet.... there's hardly any shaft resistance although there's a slight degree of side to side free play between the shaft and housing which probably accounts for the silky smooth rotation.

 Some potentiometers tolerances are so tight, between shaft and housing, that it feels as though you're torquing up a cylinder head every time you turn the volume up or down........ not so with the Bourns 91A2A series it's smooth and silky from the first rotation but not sloppy although, after a few years rotational cycles, it "may" become sloppy.

 I've noticed that pots with a tighter shaft to housing tolerance "bed in" after a while (much like pistons in a car) and tend to loosen up ...... the Bourns 91A2A feels like a pot that has already been "bed in" and this is why it feels so silky smooth in operation. In reality, the Bourns tolerances "may" not be as exacting as other manufacturers (in the shaft to housing department) so you may get a 91A2A with a tight shaft, a medium tight shaft or a loose shaft........ It could be that they are manufactured to very "precise" tolerances to ensure that each pot has that "old glove" feel (much like stonewashed jeans) and that's what I'd like to believe........ I'd hate to think that buying a Bourns pot was a case of "pot luck"

 Anyways...... so far so good! A very smooth pot and a welcome change from the stiff ALPS Blue Velvet (which becomes smoother over the years).......... Now, just a case of listening to it in action.

 Pinkie.


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## PinkFloyd

Quote:


  Originally Posted by *buggalugs* 
_ No attempt is made to bias the opamp into class A, which Dr. White considers more trouble than it's worth._

 

Hi Buggalugs,

 Dr. White has been hard at work and has come up with a really eloquent solution for biasing the opamp into class A which involves simply replacing 2 components on the board 
	

	
	
		
		

		
		
	


	




 I quote Dr. White from a recent e-mail: "If you want to bias the opamp output stage 2mA into class A then change I2 from a 3.5mA to a 5.6mA constant current diode and change R6 from 120R to 75R. In earlier versions of the headphone amp R6 was 56R, in this case reduce it to 36R. Everything else stays the same. The class A bias is simply the difference in value between the two constant current diodes, 5.6 - 3.5=2.1mA, and the change of the R6 resistor value keeps the quiescent current the same in both output transistors. The class A bias current is drawn from the negative supply rail."

 So there you go Buggalugs...... a simple 2 component mod and your opamp is biased into Class A  I'll be ordering the parts today.

 I still haven't connected the amp together as I'm waiting for the 100nF caps to arrive (should be here tomorrow) once they arrive I'll connect everything up and get down to listening to the music 
	

	
	
		
		

		
		
	


	




 I've ordered 6 browndogs from Tangent and, once I've soldered the chips onto them, I'll be auditioning the following in the White Noise amp:

 OPA 134 PA
 OPA 627 BP
 AD 825 AR
 AD 8610 BR
 AD 8065 ARZ

 I just can't wait for the caps to arrive as this looks like one "seriously" good amp and my ears are twitching in anticipation 
	

	
	
		
		

		
		
	


	




 All the best

 Pinkie.


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## PinkFloyd

At last, the parts I were waiting for arrived and I've completed the White Noise Audio amp. It worked from first switch on but all was not well with the Bourns potentiometer . It only started to kick in around the 11 o' clock position and I thought I must have wired it up incorrectly, I looked at the connections and all appeared ok so I whipped the pot out and tested it with an Ohmeter between pins 3 & 2........ The resistance stayed at 10K all the way up to the 11 o'clock position and only started to fall after 11 o'clock.

 EDIT: Farnell have inspected their entire batch of these pots and they are indeed defective so their batch will be sent back to Bourns for inspection. I've ordered a Vishay PA11 as a replacement.






 I had another Bourns pot but it suffered the exact same problem so they will both be returned to Farnell tomorrow for a refund. The only other pots I had to hand were a cheap Omeg 10K and a small Vishay 10K..... I fitted the 10K vishay and it worked great  I'll source another pot to replace the vishay but I doubt it'll be another Bourns pot...... not a good first impression with 2 of them exhibiting the same fault 






 First impressions of the amps sonic capabilities are very good indeed. I'm using a pair of opa 134 PA's at the moment (far from ideal and probably TI's most chocolaty sounding op amp) but even with the OPA 134 PA's onboard I can detect an underlying well of sheer class which is just shouting out to be fed a decent op amp to allow it to flow to the surface. I think this little amp is going to prove to be a giant, if not a giant killer.

 Dr. White favours the LM6171 and has recently been working around optimising the WNA head amp to accommodate the LM6171 which he says "enables you to pick out each individual voice in a choir instead of the entire choir sounding like one voice" now that sounds like the op amp for me!!! If there are any fellow WNA head-amp owners reading this who would like to try the LM6171 ...it's a simple case of replacing R4 (220R on both channels) with a zero ohm link which will ensure the LM6171 will not oscillate. In fact, Dr. White recommends the R4 resistors are removed (whatever op amp you are using) as he finds the op amps perform better without them in the circuit..... I told you he'd been hard at work!

 The removal of R4 (220R) along with the op amp class A mod (see post above) and LM6171 op amps apparantly transforms this amp into a totally different kettle of fish (a kettle of caviar perhaps  

 I've built the amp in it's basic guise and it sounds absolutely fantastic and I'd be happy to enjoy the music through it as it stands......... Dr. White has been hard at work the past couple of weeks trying to squeeze the last ounce of performance out of his design and I'll put his latest revisions into place before fully reviewing this amp in the Head-Fi amplification section and at http://www.rock-grotto.co.uk/xcanpropage.htm

 One thing is absolutely certain....... This is a superb kit that's easy to build, very reasonably priced and, as such, should be added to your shortlist if you're considering building a kit amp. 

 All the best.

 Pinkie.


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## PinkFloyd

It's amazing just how long a dodgy potentiometer takes to be accepted as "dodgy" by a company 

 I've tried two of the Bourns 91A2A's from Farnell and "both" have failed to drop any resistance from the 7am position up to the 11 am position (no sound at all until the volume hit the 11am position)

 After 2 weeks of alerting them to the "fact" that I was in receipt of dodgy pots they finally concede that "there may be something wrong with them" and they are sending their entire batch back to Bourns for "inspection"

 Farnells "technical" call operative stated that "logarythmic pots don't kick in until the 12pm position on the dial" hmmmmm...............

 Once I managed to bypass this neanderthal things got better and I was put onto someone called "Tim"..... "Tim" explained that I would be better with a linear pot as the measurements I were quoting were clearly ok as far as he was concerened and he suggested I "re-educate" my ears and adapt to a linear pot.

 To cut a VERY long story short, Farnell's entire batch of 91A2A's have been sent back to Bourns (6,000+ pots) as they are clearly faulty........... I asked them for a suitable replacement, considering the circumstances, and they came up with the Vishay PA11.

 I was actually asked to "pay" for the PA11 !!!!!!!!!!!!! "pay??" ............... after much "to do" they agreed to send me a free PA11.

 Big deal! I alerted them to the fact they were supplying dodgy pots and, basically, I did their QA job for them.............. I think a free pot as a gesture of goodwill for all the hassle and time wasted faffing about with these faulty pots is the least they could do. 

 Should have the Vishay pot fitted soon and will report back on it


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## Zemo

Sounding good! Any initial comparisons to our beloved PPA?

 -Z


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## PinkFloyd

Quote:


  Originally Posted by *Zemo* 
_Sounding good! Any initial comparisons to our beloved PPA?

 -Z_

 

Hi Zemo!

 I really haven't had an opportunity to compare the White Noise Head-amp to anything, as yet, as Dr. White is hard at work coming up with revisions to his design and I am putting them into place in the amp as soon as he comes up with them so, at the moment, I'm basically evaluating the improvements the mods have made over the standard kit amp (these mods will be incorporated in future kit amps so I believe)






 Dr. White has been experimenting with numerous opamps and and reckons the LM6171 brings the best out of the amp. He's been optimising the circuit to bring the best out of the LM6171 and I am awaiting a couple of LM6171's to give them a try........ 

 As soon as the amp is fully populated with all the revisions I will get down to listening to it. I can already report that in it's standard guise with OPA 134 opamps it sounded pretty ordinary (good but nothing spectacular) the class A opamp biasing improved things very slightly. Rolling in a couple of AD8610's brought about a pretty dramatic improvement to the sound and, apparantly, the LM6171's will bring about an even more pronounced improvement to the sound.

 The Vishay PA11 arrived today and works great! It's not as smooth as the Bourns and you can actually hear it squeaking when you rotate the shaft..... pretty tight but I'm sure it'll soon bed in  It may be my imagination but I believe it has made the amp sound a bit more "open" could be something to do with the gold conductive elements / legs maybe?






 It's a pity that I can't show a photo of the "entire" amp. I've had to mount some of the components on the underside of the board due to the lack of space (my fault for being arrogant and insisting that it would all fit into a Hammond 1455K1202 enclosure!) I'd have been a lot better going for a Hammond 1455N1602, that would have given me enough room to mount a stepped attenuator and more space to route the wiring etc. Oh well, I was warned but chose to shoehorn everything (carefully route 
	

	
	
		
		

		
		
	


	




 ) into a compact enclosure.

 Underside of board:


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## PinkFloyd

At last, the lid will be fitted onto the amp as it's now finally complete 
	

	
	
		
		

		
		
	


	








 Compact enclosure 

 The LM6171's were fitted into place and the input caps were removed and 2 50uF bi polar output caps were fitted. Dr. White said the LM6171's made a big difference but I didn't expect the difference to be "so" enormous!





 WNA with LM6171's on board

 When I fired the amp up my jaw dropped to the floor, Dr. White sure has managed to get every last ounce of performance out of the LM6171, instead of listening to the music as a congealed mass of instruments and voices I found myself listening to individual performers and individual instruments.... so much space around the performers and so much clarity and detail.......





 Overhead view

 The introduction of the LM6171's has transformed this amp from a "good one" to "the best I have ever heard" without a shadow of a doubt. The energy, the impact, the slam, the clarity..... it's got everything you always wish a headphone amp would give you.

 I played a favourite album (Roger Waters "in the flesh") 3 times (yes three times, that tells you a bit about what this amp is about!) and it was honestly like being back at the concert..... pretty surreal in fact.... it felt as if I was sitting in the audience and the applause and "whooping" (must have been an American audience 
	

	
	
		
		

		
		
	


	




 ) was coming from behind me, in front of me and from left to right....... there was also one instance during "shine on you crazy diamond" where a member of the audience shouted "god damn" into my right ear (track 11 - 3:02 minutes in) I have "never" heard such clarity on this recording before which is why it's now playing for a 4th time....... I can't believe the bags of information I'm hearing through this fantastic amp.






 The goosepimples have been up and down on my neck like a yo yo these past few hours and that's without the aid of alcohol and in the daylight hours...... I can't wait to hear this amp once the sun sets!

 It's just soooo musical, so real sounding and it's streets ahead of any headphone amp I have ever listened to. I was a great lover of the Williams Hart Chiarra before I listened to the WNA with LM6171's and I'm sorry to report that the WNA absolutely trounces the Chiarra (sorry because Shaun Williams is a great guy and, through our telephone conversations re: the Chiarra, we have become good friends) I'm sure Shaun will respond with a "super Chiarra" but, until that day arrives, the White Noise Audio amp is (by far) the best I have heard to date and Dr. White's work on biasing the opamp into Class A and optimising the circuit for the LM6171 has borne fruit.

 I'll review the sonic attributes of this beauty in the amplification section once 500 hours of music has passed through the circuit. My impressions so far can be marked as follows: (some amps are from memory but amps I currently have in my possession include: MF X-Can V2 Pink modded, Chiarra, GSP Solo 2004, B-Tech BT928, MINT (in a Hammond)

 Musical fidelity X-Can V2: 4 / 10 

 Musical Fidelity X-Can V2 with pink mods: 5.5 / 10

 Chiarra with OPA627 / Silmics: 8 / 10

 GSP audio SOLO: 7 .5 / 10

 B-Tech BT928 (with elna caps) 2.5 / 10

 MINT (in Hammond enclosure) 3 / 10

 White Noise Audio 9 / 10


 Before I review the White Noise Audio amp in the "amplification" section I'll send it to Nigel, another head-fi member, for an audition........ he doesn't pull his punches and calls a spade a spade......... He is the ideal person to present a "second opinion" review.

 All will be revealed


----------



## rickcr42

that last set of pictures with the headphones for comparison really allowed me personaly to get sense of the scale,the size of the amp.

 i had the impression it was larger for some reason.

 nice work mike ,very pretty amp very nice construction

 BUT 
	

	
	
		
		

		
		
	


	




 When do we get a shootout between all of your "in house" amps so we can all know who/what the winner is !


 cheers amn

 rickmeister


----------



## PinkFloyd

Quote:


  Originally Posted by *rickcr42* 
_that last set of pictures with the headphones for comparison really allowed me personaly to get sense of the scale,the size of the amp.

 i had the impression it was larger for some reason.

 nice work mike ,very pretty amp very nice construction

 BUT 
	

	
	
		
		

		
		
	


	




 When do we get a shootout between all of your "in house" amps so we can all know who/what the winner is !


 cheers amn

 rickmeister_

 

Hi Rickster,

 Yes it's pretty "compact" ,due to me shoehorning it into a Hammond 1455K1202, I was warned that things would be tight and I should have taken heed of the warnings 
	

	
	
		
		

		
		
	


	




 In true Pink fashion I went ahead with my choice of enclosure and managed to shoehorn the components into the 1455K1202 case 


 It's possible to house it in a 1455K1202 if you work to zero tolerance and have "pot luck" on your side (some would call it skill 
	

	
	
		
		

		
		
	


	




 ) but the next WNA I build will be in a larger case!

 The shootout will take place 500 hours from now (499 hours and 7 minutes to be precise 
	

	
	
		
		

		
		
	


	




 ) I think it will be a foregone conclusion, however, unless the Chiarra, solo etc shape up in the meantime. This really is the best I have heard to date.

 Dr. White sure has worked wonders with that LM6171 
	

	
	
		
		

		
		
	


	




 Pinkie.


----------



## rickcr42

glad to hear it mike.

 like most things there is no standard "plug it in and play it" design and each opamp based design really should be optimized for the individaul chip though i can't really say i blame opamp rollers for trying.

 where most run into trouble is trying to put a high bandwidth part into a low band design and then expecting the same layout ,part orientation and bypassing/ground scheme to be optimal

 The problem with some of these lightening fast chips as i see it is the attempt to mate them to slower buffer stages and that is just looking for trouble unless you limit the bandwidth of the gain stage ,and that kinda defeats the purpose of choosing the part anyway.


 I like the size and like you have tried to jimmy projects into casing at least a size to small (more like size ten feet into size six shoes) and sometimes you just get lucky man,other times you just end up with a wrecked chassis looking for something to fill it


----------



## Alick

PF - from your second photo of the 5% populated board, there are obviously three 8-pin DIL locations. Two will be for op-amps (one for each channel -LM6171's or whatever) - what's the third one for? Is it another op-amp and if so, what does it do and should it be the same type as the other two? Confusingly, it looks like two of the locations are marked IC1, but I presume that's my eyes and one of the "1"s is really a "3". Good write-up - how's the burn-in going?


----------



## The_Mac

Quote:


  Originally Posted by *Alick* 
_PF - from your second photo of the 5% populated board, there are obviously three 8-pin DIL locations. Two will be for op-amps (one for each channel -LM6171's or whatever) - what's the third one for? Is it another op-amp and if so, what does it do and should it be the same type as the other two? Confusingly, it looks like two of the locations are marked IC1, but I presume that's my eyes and one of the "1"s is really a "3". Good write-up - how's the burn-in going?_

 

The two DIPs labelled IC1 look like they're in identical amplifier sections, and the third labelled IC2 looks like it's in the power section.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_PF - from your second photo of the 5% populated board, there are obviously three 8-pin DIL locations. Two will be for op-amps (one for each channel -LM6171's or whatever) - what's the third one for? Is it another op-amp and if so, what does it do and should it be the same type as the other two? Confusingly, it looks like two of the locations are marked IC1, but I presume that's my eyes and one of the "1"s is really a "3". Good write-up - how's the burn-in going?_

 

Hi Alick,

 There are two IC1's on the board and one IC2. IC2 deals with the rail splitter and you can use an el cheapo opamp here such as an OPA134 or TLO71 or similar.

 Either side of the board can be used for left channel / right channel so components are identified as, say, R1 on the left hand side of the board and R1 on the right hand side there are two of each components (one for the left and one for the right hand side) so if R1 is a 47K resistor then you fit a 47K resistor into both R1 positions on the board.

 Hope that makes sense?

 All the best 

 Mike.

 PS: 24 hours of burn in under the belt and sounding superb...... I'm taking a few notes and will do a write up over the next couple of weeks.


----------



## rickcr42

i am curious pinksteroo .

 a lot of brit gear seems to use a 24 volt power supply followed by a rail splitter for +/- 12 volts instead of a full blown bipolar power supply (creek,musical fidelity,this amp). Why is this man ?

 just wondering out loud


----------



## Alick

Quote:


 Hope that makes sense? 
 

Perfect sense, thanks. I'll be placing my order as soon as you get the class A/LM6171 modded parts list up. Actually, I think I've figured it out anyway, but my modded list is at work. I'll wait for yours in case I missed anything. Did you fit the 22R resistors instead of the lamps?


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Perfect sense, thanks. I'll be placing my order as soon as you get the class A/LM6171 modded parts list up. Actually, I think I've figured it out anyway, but my modded list is at work. I'll wait for yours in case I missed anything. Did you fit the 22R resistors instead of the lamps?_

 


http://www.rock-grotto.co.uk/class%2...%20biasing.htm for the class A biasing.

 To optimise the circuit for the LM6171 simply remove R4 ( 220R ) and jumper over its position on the pcb ( both channels obviously )

 You'll also need to fit 2 output caps.... anything over 2.2MFD will do and they MUST be bi polar....... fit them between signal out and headphone socket (one for each channel) Choice of cap is down to you but I went for the first thing that came to hand..... 25MFD ALCAP bi polar electrolytic. you may prefer polyprops (I hate them) or polyesters but, as long as they are bi-polar, anything over 2u2 (2.2MFD) will suffice. I chose 25uF and the bass is toe curlingly deeeeep 

 There's no need to fit the input caps (C1 2.2uF polyprops) and you can jumper over the pads but if you are going to use the LM6171's (highly recommended!!) then you "must" fit output caps (unless you can think of a better way)

 Whether or not you choose to fit the LM6171's it's best to remove R4 (220R) anyway ....... Dr. White says " I originally included R4 (220R) because I'd read that it acted as a "stopper" resistor and improved stability in opamp plus buffer type circuits. In fact, in this circuit and with very fast opamps, it does exactly the reverse and causes the amplifier to oscillate. You must try the LM6171, its one of my favourites because the the wonderful clarity of the sound that it produces."

 I'm in the process of putting all this info and tweaks together Alick and will be uploading everything to my website shortly (hopefully by this time next week) so please bear with me 
	

	
	
		
		

		
		
	


	




 I haven't yet fitted the resistors in place of the lamps and really don't think it's necessary...... they are there as a form of protection and to remove them would make the amp less bullet proof. I'll leave them in the circuit for the time being and remove them once I've finished fine tuning things 

 By the way, if you fit the LM6171's, always ensure that your headphones are connected when you power the amp up.... Dr. White explains: "The only way you can get instability using LM6171s with my headamp is if you switch on with no load, i.e. no headphones plugged in. This eventuality can be guarded against by wiring dummy load resistors on the headphone socket - they get switched out as soon as you plug in the headphones."

 Hope that's enough for you to be getting on with Alick 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *rickcr42* 
_i am curious pinksteroo .

 a lot of brit gear seems to use a 24 volt power supply followed by a rail splitter for +/- 12 volts instead of a full blown bipolar power supply (creek,musical fidelity,this amp). Why is this man ?

 just wondering out loud_

 

It's a secret British recipe passed down through the generations........ I'm afraid you'll have to remain in the dark on this one 
	

	
	
		
		

		
		
	


	




 Dr. White may be able to answer your question and I'll pass it on to him.

 All the best.

 Pinkie. (pinksteroo?)


----------



## Alick

Quote:


 Hope that's enough for you to be getting on with Alick 
 

More than enough - thanks a lot. I'll get ordering then...


----------



## PinkFloyd

I've got a varied selection of bipolar caps and can send you a couple. Be warned......... I'm not a polypropelyne lover and find non polar electrolytics to sound more "honest" to the event........... polyprops may "measure" up but IMO they impart a rubbery signature to the sound. 


 I've got a couple of 25uF ALCAPS, two Bennic 12uF's, a couple of ANSAR 12uF supersounds (huge) and a few Nitai 100uF bipolars. If you're a polyprop convert then the Evox / Rifa 250V are a good cap.

 Enjoy building the amp Alick and be sure to report back with your impressions..........

 All the best.

 Mike.


----------



## Alick

I might just take you up on the very generous offer of the Alcaps Pinkie - thanks. I'll let you know when I've got the rest of the kit and am ready to build. I've a feeling I might want to experiment with the class A mod in and out to see if the advantages of class A outweigh the need for the output capacitors. You suggested the improvement was marginal?

 Cheers again

 Alick


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I might just take you up on the very generous offer of the Alcaps Pinkie - thanks. I'll let you know when I've got the rest of the kit and am ready to build. I've a feeling I might want to experiment with the class A mod in and out to see if the advantages of class A outweigh the need for the output capacitors. You suggested the improvement was marginal?

 Cheers again

 Alick_

 

Output caps are essential with the LM6171............ no need for any caps with the AD8610 OPA627 etc. Trust me, the LM6171 is the way to go......... "astonishing" is one word to describe the improvement.

 Pinkie.


----------



## PinkFloyd

Quote:


  Originally Posted by *rickcr42* 
_i am curious pinksteroo .

 a lot of brit gear seems to use a 24 volt power supply followed by a rail splitter for +/- 12 volts instead of a full blown bipolar power supply (creek,musical fidelity,this amp). Why is this man ?

 just wondering out loud_

 

This is all I could get out of Dr.White at such short notice but I trust it answers your question Ricksterooni?


 "The points that rickr42 makes about fast opamps and buffers are quite correct - you can't just fling together any fast opamp and any old output stage and expect them to work. You have to design with high speed in mind, and do a compatable pcb layout. I think there are going to be an awful lot of disappointed people buying AD8065s on adaptors and expecting them to be general purpose drop in replacements for all opamp circuits.
 As to the 24V plugtop plus rail splitter, the rationale goes like this. Plugtop regulated supplies offer very good performance for very little money. If you have high impedance headphones you need a decent output voltage from your headamp. Plugtop power supplies don't normally come in split rail versions - they are available but expensive. The highest commonly available voltage from a regulated plugtop supply is 24V. So use a 24V supply and rail splitter to get +/-12V.
 My headamp will work with a conventional split rail psu giving anything from +/-6V to +/-18V and there is a separate connector on the pcb for this purpose. To use a split rail psu you just unplug the rail splitter opamp and connect power to the three pin power connector. The WNA headphone amplifier sounds better when powered from a really good split rail supply, like my cascode power supply or a Jung type supply, rather than a plugtop psu. Good split rail power supplies are expensive and you're into diminishing returns territory here. Headamp plus plugtop gives you most bang per buck; whilst headamp plus good split rail gives you best performance regardless of cost. Pay your money and take your choice!


 Regards, David"

 Hope that answered your question Rick?

 Mike.


----------



## rickcr42

Quote:


 Hope that answered your question Rick? 
 

absolutely ,thanks mike.

 I was mainly just curious . I guess it just comes down to economics and circuit complexity like most things in audio and choices need to be weighed as to where can you cut and still produce something good .

 and i agree 100% with that actually


----------



## rickcr42

Quote:


 I think there are going to be an awful lot of disappointed people buying AD8065s on adaptors and expecting them to be general purpose drop in replacements for all opamp circuits. 
 

another good point i agree with totally


----------



## PinkFloyd

Quote:


  Originally Posted by *rickcr42* 
_another good point i agree with totally_

 

You're very agreeable all of a sudden Rick......... are you ok or is it the medication kicking in? 
	

	
	
		
		

		
			






 All the best mate

 Mike.


----------



## rickcr42

it's the heat dammit ! that and the humidity plus this damn middle ear infection that keeps.......ooops......fell again dammit......knocking me over ! 

 So I have to take it easy so i don't boil over and the top of my head comes flying off !

 Messy .Very messy.


----------



## PinkFloyd

That's the lid on for a while (the weekend at least 
	

	
	
		
		

		
		
	


	




 ) 

 The amp is sounding absolutely fantastic 
	

	
	
		
		

		
		
	


	




 fully clothed pics:


----------



## Alick

Looks good Pinkie, nice job. From what I can judge, the next size up case should be about as deep and high as the Solo but slightly narrower? I've had a prompt and helpful response from David and I'm sending him a cheque today. I'll order the other bits from Maplin and Rapid this afternoon. How many hours burn-in now? Is the sound changing at all?


----------



## raja

HI,

 I have the WNA line buffer which seems to use an almost identical topology to the headphone amp, in fact the buffer drives headphones very well. My experience with the opa627's in place is that once you turn up the volume and push them hard you can hear the sibilance.......
 AD825's seem to work pretty well although I haven't connected up a scope and checked for motorboating, as I have heard this can happen. However I do think this can be cured by using good decoupling caps directly at the opamp pins. One thing I did chance on whilst messing around is to replace the LF351 after the rail splitter with one of the spare opa627's I had. 

 Try it out and let me know what you think..... 

 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Looks good Pinkie, nice job. From what I can judge, the next size up case should be about as deep and high as the Solo but slightly narrower? I've had a prompt and helpful response from David and I'm sending him a cheque today. I'll order the other bits from Maplin and Rapid this afternoon. How many hours burn-in now? Is the sound changing at all?_

 

Hi Alick,

 I measured the Solo enclosure and give or take 3mm it's the same size as the Hammond you're contemplating using.... a much more sensible size to use 
	

	
	
		
		

		
		
	


	




 You'll definitely get an ALPS blue velvet in there, or even one of David White's stepped attenuators, plenty of room.

 The sound sure is starting to open out giving a broader soundstage.... it's had about 70 hours or so being fed a diet of radio 2 so it won't be much longer before I start listening to it in depth with the CD player as the source 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_HI,

 I have the WNA line buffer which seems to use an almost identical topology to the headphone amp, in fact the buffer drives headphones very well. My experience with the opa627's in place is that once you turn up the volume and push them hard you can hear the sibilance.......
 AD825's seem to work pretty well although I haven't connected up a scope and checked for motorboating, as I have heard this can happen. However I do think this can be cured by using good decoupling caps directly at the opamp pins. One thing I did chance on whilst messing around is to replace the LF351 after the rail splitter with one of the spare opa627's I had. 

 Try it out and let me know what you think..... 

 Thanks
 Raja_

 

Hi Raja,

 I'm not using the OPA627's. I tried the AD8610's and the AD825 and both sounded very nice indeed (you'll have to replace R4 '220ohm' with a zero ohm jumper) to make the opamps unconditionally stable and also bias the opamp into class A as explained in another part of this thread. David found that the 220ohm "stopper" resistors actually had the opposite effect and caused the amp to oscillate.

 I'm using the LM6171's with non polar output caps and they are as stable as anything 
	

	
	
		
		

		
		
	


	




 Just be sure to power the amp up with the headphones connected (load) if you're using these opamps.

 David explains:

"The only way you can get instability using LM6171s with my headamp is if you switch on with no load, i.e. no headphones plugged in. This eventuality can be guarded against by wiring dummy load resistors on the headphone socket - they get switched out as soon as you plug in the headphones.
 The output offset of my headamp with LM6171s is 200mV. You can reduce this by lowering the 47k input resistor to 10k but the best option is to use an output capacitor - either a 4u7 polypropylene or any similar, or greater, value of non-polarised electrolytic. The design described in the attachment trades stability for offset voltage whereas I've done exactly the reverse. These considerations only apply to bipolar input opamps; the output offset is usually only a few mV with pretty much any fet input opamp ( OPA134, OPA627, AD825, AD8065, etc ) using a wide range of input and feedback resistor values."

 The improvement the LM6171's bring about is night and day compared to the AD8610 and AD825.... the law of diminishing returns doesn't apply with the LM6171 the improvement is "immense" To give an example, I listened to a Frank Sinatra capitol gold recording with the AD8610 and AD825 and the orchestra came across as one integrated mass of music. I rolled the LM6171's in and I was presented with musicians with space around them and each instrument was easy to follow and presented with so much room that you could walk around the musicians and shake their hands....... now, that's seriously good stuff!

 David reckons the incredible "3200" slew rate of the LM6171 has got a lot to do with this as it's got the speed to cope with the start / stops of "many" musicians playing at once and can cope with the demand....... it's awesome and, I don't know how or why it does what it does but I'm over the moon that David has managed to get the best out of this prima donna of an opamp...... optimised correctly it's the best you'll ever hear and David has managed to tame it....... superb.

 I'll try an OPA 627 in the rail splitter section Raja...... what difference will that make to the sound? I can't see it making any difference at all?

 All the best.

 Pinkie.


 PS: are you "Raj" from http://www.audiocircle.com/circles/v...ic.php?t=11202 ? 

 Welcome to Head-Fi Raja


----------



## raja

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Raja,

 I'm not using the OPA627's. I tried the AD8610's and the AD825 and both sounded very nice indeed (you'll have to replace R4 '220ohm' with a zero ohm jumper) to make the opamps unconditionally stable and also bias the opamp into class A as explained in another part of this thread. David found that the 220ohm "stopper" resistors actually had the opposite effect and caused the amp to oscillate.

 I'm using the LM6171's with non polar output caps and they are as stable as anything 
	

	
	
		
		

		
		
	


	




 Just be sure to power the amp up with the headphones connected (load) if you're using these opamps.

 I'll try an OPA 627 in the rail splitter section Raja...... what difference will that make to the sound? I can't see it making any difference at all?

 All the best.

 Pinkie.


 PS: are you "Raj" from http://www.audiocircle.com/circles/v...ic.php?t=11202 ? 

 Welcome to Head-Fi Raja 
	

	
	
		
		

		
		
	


	


_

 


 Hi,

 Yep that's me, try using the opa627 in the position I suggested and see if you can hear a difference, I would say you get a better midrange, but I'll reserve comment as I haven't done conclusive tests...... Just wanted to see if you could hear a difference at all, it's quick and easy asuuming you have the chip on a socket...

 I haven't personally tried the lm6171 in the amp yet, I'll have to research a bit further and see what other high speed opamps are available, there's always something new around the corner. Granted though the slew rate of the 6171 is kinda unique. I may give it a bash, but I also want to check out other high speed fet opamps, to see if I can find a middle ground, perhaps slew rate over 1000v/us, with low offset, without the need for a coupling cap (I dislike them), although in this situation it still seems the sound is improved regardless.........

 Thanks for the welcome, and well done for all the effort you've put in to the write ups, it's about time David's products got the recognition they deserve, amazing price performance ratio. David is one of the few guys around that will sell you bare pcb's so you can get your own parts if you wish, he's very flexible in his approach, and it seems the final dollar is not always his priority.............

 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi,

 Yep that's me, try using the opa627 in the position I suggested and see if you can hear a difference, I would say you get a better midrange, but I'll reserve comment as I haven't done conclusive tests...... Just wanted to see if you could hear a difference at all, it's quick and easy asuuming you have the chip on a socket...

 I haven't personally tried the lm6171 in the amp yet, I'll have to research a bit further and see what other high speed opamps are available, there's always something new around the corner. Granted though the slew rate of the 6171 is kinda unique. I may give it a bash, but I also want to check out other high speed fet opamps, to see if I can find a middle ground, perhaps slew rate over 1000v/us, with low offset, without the need for a coupling cap (I dislike them), although in this situation it still seems the sound is improved regardless.........

 Thanks for the welcome, and well done for all the effort you've put in to the write ups, it's about time David's products got the recognition they deserve, amazing price performance ratio. David is one of the few guys around that will sell you bare pcb's so you can get your own parts if you wish, he's very flexible in his approach, and it seems the final dollar is not always his priority.............

 Thanks
 Raja_

 

Hi Raj,

 I sure will try an OPA627 in IC2 and will get back to you on that. I'm just waiting for another batch of OPA627BP's, 3 of them 
	

	
	
		
		

		
		
	


	




 to be delivered.

 I'll also try the AD8605, AD8610, AD825, in IC2.

 I strongly suggest you try the LM6171 as per Dr. White's latest revision to his design Raj. He wouldn't have spent the past month working on this if he thought he could have squeezed more performance out of his amp by utilising another op amp.......... He has chosen the LM6171 for good reason, it's the best in this application. All the best.

 Mike.


----------



## Alick

Placed orders with Maplin and Rapid and sent a cheque off to WNA at the weekend - now waiting patiently...


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Placed orders with Maplin and Rapid and sent a cheque off to WNA at the weekend - now waiting patiently..._

 

Ahhhh! so you're the culprit who snapped up Maplins last N77AL 
	

	
	
		
		

		
		
	


	




 I ended up having to order one from RS components as Maplins were out of stock. £15 (with VAT and delivery) from RS...... bloomin' robbers 
	

	
	
		
		

		
		
	


	




 I've also got one of Maplins N85AL enclosures on back order and they expect it will arrive within 28 days.

 I don't quite know what I'm going to do with all these enclosures but the N77AL will be used for another WNA amp I'm building for a fellow head-fier.... I may transfer my amp into a roomier enclosure also 
	

	
	
		
		

		
		
	


	




 Did you manage to get the BD140's from Rapid? When I placed my order they were out stock and I ended up getting them from Maplins @ 27p each. Rapid, it transpires, also do the constant current diodes for 55p each..... the 5.3mA order code is 47-2610 and the 3.5mA order code is 47-2606 they also do the 12V 60mA incandescent lamps @ 20p each order code 41-0225. You'll also need some M3 nuts and bolts for the TO220 heatsinks... give me your details and I'll send some to you as I've got tons of the things.

 I'll start building once all the parts arrive so looks like we will both be building at the same time Alick 
	

	
	
		
		

		
		
	


	




 I've fitted an AD8065 into IC2 and I believe Raja is correct... a tad more midrange detail..... I haven't got the OPA627's yet but the AD8065 also makes a slight improvement when fitted into IC2.

 Listening to Mike Oldfield's "tubular bells lll" at the moment and I've never heard it quite so good before... it normally sounds congested and shrill, glassy and splashy but through the WNA amp every instrument is playing seperately and it's a darned sight easier on the ears as a result. This amp majors on presenting individual instruments / singers with "space" around them instead of belting everything into your ears en masse....... believe me Alick, you'll rediscover all of your recordings once you fire this amp up.... the information it delivers is quite astonishing.

 Keep us up to date on the progress of your building and I can't wait to hear your initial impressions of the sound (try it with the LM6171's and output caps first)

 All the best

 Mike.


----------



## raja

Hi Pinkfloyd,

 Glad you tried the chip in IC2, have you tried the headamp with no coupling caps, but with 10k input resitors instead? Of course measure the dc offset first.....

 I have a feeling that ad8065 will outperform others in ic2 position, although I have heard of people preffering the ad825 in the jung reg ciruicts when they power analog stages.....

 I will try my buffer with super regs some time soon, increasing the rails to +16v/-16v should provide an added bonus. I will also see if I can get the higher current diodes, again using the heatsinking precautions for the ouput pair......

 FWIW I also have the white noise mos250 audiophile version, running off active psu's (1 per channel) with about 580ma bias accross the mosfets, sounds very good.

 I did notice you are ruinning the head amp with standard metal films? Or are you using the rapid electronice 0.4w 0.1% types?

 My version uses the welwyn 0.1% types, these sound better than the standard metal films, increases in transparancy accross the range, and much bigger open bass.....

 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi Pinkfloyd,

 Glad you tried the chip in IC2, have you tried the headamp with no coupling caps, but with 10k input resitors instead? Of course measure the dc offset first.....

 I have a feeling that ad8065 will outperform others in ic2 position, although I have heard of people preffering the ad825 in the jung reg ciruicts when they power analog stages.....

 I will try my buffer with super regs some time soon, increasing the rails to +16v/-16v should provide an added bonus. I will also see if I can get the higher current diodes, again using the heatsinking precautions for the ouput pair......

 FWIW I also have the white noise mos250 audiophile version, running off active psu's (1 per channel) with about 580ma bias accross the mosfets, sounds very good.

 I did notice you are ruinning the head amp with standard metal films? Or are you using the rapid electronice 0.4w 0.1% types?

 My version uses the welwyn 0.1% types, these sound better than the standard metal films, increases in transparancy accross the range, and much bigger open bass.....

 Thanks
 Raja_

 

Hi Raja,

 I'll get experimenting with the output caps / 10k resistors when I'm building my second WNA amp this week and see which sounds the best. As you can appreciate, there are so many things to try out and it's not a good move rushing to try them all out at once.

 The improvement the LM6171's brought about was nothing short of incredible so I'll let them bed in a while longer and really get used to the sound before I remove the output caps and try 10K input resistors in their place. I may even try a few different output caps first and take note on which type sound the best before trying the 10K input resistors. At the moment I've got a couple of ALCAP axial 25uF output caps fitted and I'm "very" impressed with the sound indeed. I'll try some polyprops, some polyesters and some of those cheap Nitai non polars (5p each!) ...... oh, I'll also try some Bennic bi polar electrolytics (they sounded better than Solens in a loudspeaker crossover I made if memory serves) I won't go overboard in the cap selection as you can start to lose your sanity (and your money) once you go down the audio boutique route....... ANSAR supersounds are about as far as I'll go with polyprops and I prefer the sound of electrolytics...... another topic for another time 
	

	
	
		
		

		
		
	


	




 The resistors I employ in the circuit are the trueohm 0.1% 15ppm temp. coef types. I refuse to pay £1 each for the Welwyn RC55Y varieties when I can get the trueohm resistors for 25 pence each which have the exact same specs as the Welwyns at a quarter of the cost. The extra 75 pence for the Welwyns buys you a resistor with a black coating...... pretty, but I don't look at the resistors when I'm listening to the music 
	

	
	
		
		

		
		
	


	




 I'm working on a little trick myself and will announce it "if" it proves succesful... I don't want to over egg the pudding and ruin the sound just for the sake of scoring a point but if it works out I'll let you know 
	

	
	
		
		

		
		
	


	




 I "honestly" don't think anything can make such a dramatic improvement to the sound like the introduction of the LM6171's brought about and any further tweaks to the circuit can only bring about very marginal improvements....... you can't get better than "best", as much as you try, and messing about too much can result in "less" ........ been down that road and have several T-Shirts to prove it 
	

	
	
		
		

		
		
	


	




 Let's enjoy the moment and listen to the optimised WNA with LM6171's on board before we race off in search of the holy grail like headless chickens...... take a deep breath, sniff the roses and listen to what the designer of the amp thinks sounds the best (I agree with him)

 Again, before increasing the rails to +16v/-16v, try out Dr. White's LM6171 mod. A lot of people can't see the wood for the trees and they miss the point entirely and end up completely off course and find themselves in a desert...... 

 Try the LM6171's as the Doctor prescribed and report back on your findings 
	

	
	
		
		

		
		
	


	




 All the best.


 Mike.


----------



## Alick

Quote:


 Ahhhh! so you're the culprit who snapped up Maplins last N77AL 
 

Oops - guess I blew my chance of the output capacitors then? 
	

	
	
		
		

		
		
	


	



  Quote:


 have you tried the headamp with no coupling caps, but with 10k input resitors instead? Of course measure the dc offset first..... 
 

Raja - are you talking about input coupling or output coupling capacitors (or both?). I thought Mike had replaced the input couplers with zero ohm links? Forgive the questions - I haven't seen the schematics yet so I'm shooting in the dark.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Oops - guess I blew my chance of the output capacitors then? 
	

	
	
		
		

		
		
	


	




 Raja - are you talking about input coupling or output coupling capacitors (or both?). I thought Mike had replaced the input couplers with zero ohm links? Forgive the questions - I haven't seen the schematics yet so I'm shooting in the dark._

 

Zero ohm links over C1 and "anything" you desire (2u2 minimum up to a maximum of whatever you can fit into the enclosure...... the higher the capacitance the lower the bass but I'd class 5uF as optimal and anything over that as overkill........ I'm using 25uF ALCAPS) as output caps between signal out and headphone socket (left and right channels) so from sig out solder one leg of the cap to either left or right channel on the headphone socket.

 All the best.

 Mike.


----------



## omi2

Quote:


  Originally Posted by *PinkFloyd* 
_Ahhhh! so you're the culprit who snapped up Maplins last N77AL 
	

	
	
		
		

		
			





 I ended up having to order one from RS components as Maplins were out of stock. £15 (with VAT and delivery) from RS...... bloomin' robbers 
	

	
	
		
		

		
		
	


	




 I've also got one of Maplins N85AL enclosures on back order and they expect it will arrive within 28 days.

 I don't quite know what I'm going to do with all these enclosures but the N77AL will be used for another WNA amp I'm building for a fellow head-fier.... I may transfer my amp into a roomier enclosure also 
	

	
	
		
		

		
		
	


	




 Did you manage to get the BD140's from Rapid? When I placed my order they were out stock and I ended up getting them from Maplins @ 27p each._

 

hehe guilty of that as well here, decided to pop into the thread and see whats new 
	

	
	
		
		

		
		
	


	




 all bits ordered and half here already, missing the all important PCB. bah also just realised i wasted money ordering some of the stuff, we happened to have stocks of most of the stuff and the technicians were only too happy to give me loads of them. fingers crossed construction over the weekend.

 oh yeah cheers for the diagram, looks like that will come in handy


----------



## raja

Hi,

 Don't worry, I'm not in search of a holy grail with this amp now. I've had it for around 18 months or so. At the moment it's going to be used as a gain stage for my phono amp, maybe I'll drive headphones with it.....

 AS for the regulators, I was part of the super regulator group buy on diyaudioforums, so I ended up with a number of positive and negative pcbs, so it's really no problem for me to try them out.
 In any case running the rails at the opamp margins is always better, and can make quite a difference, especially when such fast opamps as the lm6171's are concerned. I've done extensive listening in situations with and without coupling caps, and to my ears you ALWAYS lose resolution thru them , just listen to cymbals etc, you'll notice the difference in texture. Hence I always try to avoid them wherever possible....

 Thanks
 Raja


----------



## Alick

Thanks for the diagram Mike. That was what I thought you meant - links over C1 and big caps in series with the output. I just wasn't sure what Raja was suggesting with the 10k resistors. However, I've re-read his mail and I notice he said 10k _input_ resistors, so I guess he means those rather than the zero ohms link.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Thanks for the diagram Mike. That was what I thought you meant - links over C1 and big caps in series with the output. I just wasn't sure what Raja was suggesting with the 10k resistors. However, I've re-read his mail and I notice he said 10k input resistors, so I guess he means those rather than the zero ohms link._

 

On the subject of the 10k input resistors I received this from David White which should clarify matters:

 "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."

 So, that kinda clears that up and if you're going to gain the huge advantages of the LM6171's it looks as though there's no way around the non polar output caps..... it's a small trade off in one department for a massive improvement in another.

 Remember Alick, you only need the output caps if you are using the LM6171's..... if you're using OPA627's AD8610's etc. you need neither input or output caps in place. I believe the LM6171's with output caps sound streets ahead of the AD8610's without input or output caps... the output caps are a necessary compromise if you want to use the LM6171's and the benefits far outweigh the disadvantages (if indeed audible?)

 All the best.

 Mike.


----------



## Alick

If it's good enough for David and you, it's good enough for me. I tend to be a "detail junkie" so I'm completely sold on the idea of the LM6171's.

 Cheers

 Alick


----------



## guzzler

just out of interest, has Dr White gone about balancing the input impedances to the opamp? You shouldn't need an output cap on a well balanced amp, using reasonably well matched components?

 g


----------



## raja

Hi,

 the amp is well balanced, no expert but I think that most of the opamps used are fet input? In this case the dc offet is very low and there is no need for any type of coupling cap in this circuit, however the lm6171 is a different story. Most of the time the amp can be completely dc coupled, the only exception is in cases like this. Sinking around 200ma of dc offset when the lm6171 is used can't be easy without caps, or other circuitry, which I'm sure have their own sonic signature.

 Unless of course you know another method?
 Thanks
 Raja


----------



## guzzler

FET input amps (AD86*0, OPA6*7 and most opamps you see mentione here) are very tolerant of unbalanced inputs, but the LM6171 as a bipolar input amp can be destabalised, and hence give the DC offset (it's voltage not current) that is being seen. If the inputs are properly balanced, the input DC level is low, and the gain is not too high there should be negligible DC offset. Is the amp compensated? If not, there could be phase problems with the complementary pair on the output (correct me if there isn't one)... It's worth looking at the Meier project of HeadWize that uses the LM6171 completely DC coupled throughout...

 g


----------



## Alick

Got home tonight - three parcels in the hallway, one each from Maplin, Rapid and WNA. Excellent service considering I only placed orders on Sunday night and didn't pay extra for quick delivery. Especially good service from WNA as (a) they're a (part time?) one-man band and (b) they haven't got my money yet as it's a pay by cheque operation. 

 I know what I'm doing this weekend (unless SO says otherwise... 
	

	
	
		
		

		
		
	


	




)


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Got home tonight - three parcels in the hallway, one each from Maplin, Rapid and WNA. Excellent service considering I only placed orders on Sunday night and didn't pay extra for quick delivery. Especially good service from WNA as (a) they're a (part time?) one-man band and (b) they haven't got my money yet as it's a pay by cheque operation. 

 I know what I'm doing this weekend (unless SO says otherwise... 
	

	
	
		
		

		
		
	


	




)_

 

Bl**dy superb service from all three....... totally agreed! I placed an order with Maplins and Rapid yesterday afternoon and the orders arrived this morning at 10 am, excellent! WNA are incredibly fast also..... usually next day delivery


----------



## PinkFloyd

As just mentioned my Rapid, Maplins and RS order arrived this morning and I've just spent the past hour fitting the ALPS pot, DC socket, headphone socket, Gold plated RCA sockets, switch and blue LED onto the "larger" Hammond enclosure and it just looks and feels soooo much better with bags more room to work with 
	

	
	
		
		

		
		
	


	




 Just waiting for the board from WNA and I'll populate it and wire everything up..... I just feel so much happier with that ALPS RK27 sitting at the centre of the front panel  the foil on top of the pot is Rainbow foil 
	

	
	
		
		

		
		
	


	




 Here's a preview of just how much more room there is inside the larger Hammond:


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi Pinkfloyd,

 Glad you tried the chip in IC2, have you tried the headamp with no coupling caps, but with 10k input resitors instead? Of course measure the dc offset first.....

 I have a feeling that ad8065 will outperform others in ic2 position, although I have heard of people preffering the ad825 in the jung reg ciruicts when they power analog stages.....

 I will try my buffer with super regs some time soon, increasing the rails to +16v/-16v should provide an added bonus. I will also see if I can get the higher current diodes, again using the heatsinking precautions for the ouput pair......

 FWIW I also have the white noise mos250 audiophile version, running off active psu's (1 per channel) with about 580ma bias accross the mosfets, sounds very good.

 I did notice you are ruinning the head amp with standard metal films? Or are you using the rapid electronice 0.4w 0.1% types?

 My version uses the welwyn 0.1% types, these sound better than the standard metal films, increases in transparancy accross the range, and much bigger open bass.....

 Thanks
 Raja_

 

Holy cornetto Batman! I've replaced the 47k input resistors with 10K input resistors, as suggested, and they'll be staying put that's for sure! Maybe it's something to do with the amp burning in or maybe it's due to the 10K resistors I dunno but one thing's for sure...... it sounds "even" better since swapping the 47K's for the 10K's...... there is so much clarity it's as though you're listening to seriously good equipment in the dead of night with no ambient noise..... just pure spine tingling, goose bump inducing crystal clear sound.

 It's hard to find anything these days that will make the hairs on the back of my neck stand up (the remaining few!) but this little amp is managing to excite them with quite worrying regularity 
	

	
	
		
		

		
		
	


	




 I honestly think it's time to weld the bonnet shut..... well, I may experiment with different types of output caps first  but, no, seriously this little amp has blown me away and I haven't listened to so much music, and enjoyed every moment of it, for a "very" long time. The way the WNA presents the music is absolutely addictive and I just can't prise myself away from it...... 

 To heck with the technicalities of output caps, resistors or any other components..... this amp presents your ears with sweet music and it's the first hi-fi component in years that has managed to draw me into the music..... it's a beauty.

 Mike.

 PS: The cymbals and hi hat on the Buddy Rich album "Tuff Dude" track 3 '2nd Avenue blue' sound anything "but" splashy or bright...... in fact, they are pretty true to the event and realistic sounding and the starts and stops of the rimshots are rapid and sound like they should "thwack!!" (followed by an inky black silence) as opposed to thwack.k.k.k.k.k.k.shhhhhh I can detect from the recording that Buddy had tuned his snare for speed....... anyways I won't ramble on about drumming but can assure you that (in this application) output caps don't necessarily equate to "spashy" cymbals 

 All the best.

 Mike.


----------



## Alick

An amplifier that is both musical and capable of delivering detail? Not often you get both together...especially at this price! I'm going to have to find the time to build this very soon...


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_An amplifier that is both musical and capable of delivering detail? Not often you get both together...especially at this price! I'm going to have to find the time to build this very soon..._

 

The "price" kinda says "this amp shouldn't be doing what it's doing" but it does so I am not complaining  

 Have fun building it Alick and report back with your findings ASAP.

 All the best.

 Mike.


----------



## philodox

this amp looks very interesting... it will be quite a while before I am at the level where I can try to build one, but I think I just might

 is there any way you could set up a mount for the caps so that you could swap them out easily for cap rolling? [kind of in the same way as people do with their opamps]


----------



## PinkFloyd

Quote:


  Originally Posted by *philodox* 
_this amp looks very interesting... it will be quite a while before I am at the level where I can try to build one, but I think I just might

 is there any way you could set up a mount for the caps so that you could swap them out easily for cap rolling? ]kind of in the same way as people do with their opamps]_

 

Not that I'm aware of but I'm sure someone will prove me wrong and provide a link to a cap rolling mounting device (I hope)


----------



## bpribadi

Quote:


  Originally Posted by *PinkFloyd* 
_... The improvement the LM6171's brought about was nothing short of incredible so I'll let them bed in a while longer and really get used to the sound before I remove the output caps and try 10K input resistors in their place. I may even try a few different output caps first and take note on which type sound the best before trying the 10K input resistors. At the moment I've got a couple of ALCAP axial 25uF output caps fitted and I'm "very" impressed with the sound indeed. I'll try some polyprops, some polyesters and some of those cheap Nitai non polars (5p each!) ...... oh, I'll also try some Bennic bi polar electrolytics (they sounded better than Solens in a loudspeaker crossover I made if memory serves) I won't go overboard in the cap selection as you can start to lose your sanity (and your money) once you go down the audio boutique route....... ANSAR supersounds are about as far as I'll go with polyprops and I prefer the sound of electrolytics...... another topic for another time 
	

	
	
		
		

		
		
	


	




 Try the LM6171's as the Doctor prescribed and report back on your findings 
	

	
	
		
		

		
		
	


	



_

 

Hi Mike, thanks for sharing! I would like to try the LM6171, eventhough using output caps is against the philosophy for good audio circuits. (What the heck 
	

	
	
		
		

		
		
	


	




 )

 Do you mind to share your circuit diagram? If it is not propietary 
	

	
	
		
		

		
		
	


	




 Thanks!
 Bram


----------



## raja

Hi,

 I think the that David White would have to be asked before someone posts the circuit online............

 It's not that complex really, I sure there's other suff like it on the web somewhere, in fact DVV (who posts on audiocircle occasionally) has a website which shows opamp circuits with similar components around them..........

http://www.zero-distortion.com/start.htm

 look for boosting opamp output currents......


 Thanks
 Raja


----------



## PinkFloyd

[size=xx-large]Warning![/size] if using the LM6171's do not use the OSCON caps as they cause the LM6171's to oscillate like mad 
	

	
	
		
		

		
		
	


	




 I fitted the OSCON's earlier and fired the amp up to be presented with a high pitched squeal coming through the headphones and a very very hot transistor which burnt the end of my finger.

 I spoke to David and the LM6171 datasheet does say that low ESR (low impedance) caps can cause the LM6171's to oscillate. I removed them and fitted standard 85c caps and all's back to normal.


----------



## PinkFloyd

Quote:


  Originally Posted by *guzzler* 
_FET input amps (AD86*0, OPA6*7 and most opamps you see mentione here) are very tolerant of unbalanced inputs, but the LM6171 as a bipolar input amp can be destabalised, and hence give the DC offset (it's voltage not current) that is being seen. If the inputs are properly balanced, the input DC level is low, and the gain is not too high there should be negligible DC offset. Is the amp compensated? If not, there could be phase problems with the complementary pair on the output (correct me if there isn't one)... It's worth looking at the Meier project of HeadWize that uses the LM6171 completely DC coupled throughout...

 g_

 


 Hi Guzzler,

 On this subject Dr. White responds with the following:

 "The input offsets are not the same at the inverting and non-inverting inputs of the LM6171 in my design ( i.e. the inputs are not "balanced", a poor choice of words ) for good reason. The input impedance, feedback loop resistances, and output offset are intimately connected, but as Raja says this only really matters with bipolar opamps. If you choose a feedback resistance anywhere remotely close to the value recommended by National, and you want a small output offset, then the input impedance can only be of the order of tens, or low hundreds, of ohms. Not a problem if the LM6171 is used at radio/video frequencies, as intended, where the standard input and output impedances are either 50 or 75 ohms. For audio we like our input impedances to be around 10kohm, or higher. In order to achieve this, with a low output offset, the resistors in the feedback loop would need to be 10k and 33k rather than 1k and 3k3. This would be fine with slow/moderate speed bipolar opamps intended for audio use. However the 33k resistor, in combination with stray circuit capacitance, would almost certainly introduce enough phase shift to cause a very fast opamp like the LM6171 to oscillate; that's why you never see high values of feedback resistors in opamp circuits intended for use at radio/video frequencies. Unfortunately, unless you had access to a very fast oscilloscope or rf spectrum analyzer ( and most diyers don't ), you might never know the LM6171 is oscillating. A high quality output capacitor is a good solution to this dilemma.
 If I were designing a headphone amp specifically for use with the LM6171 I'd use a preset potentiometer and a resistor to inject a small voltage in to the inverting input to zero the output offset voltage. This way you get the best of all worlds - reasonable input impedance, low value feedback resistors, zero output offset, and no output capacitor.

 David"

 Hope that answered your question Guzzler.

 Mike.


----------



## Alick

Quote:


  Originally Posted by *PinkFloyd* 
_[size=small]Warning![/size] if using the LM6171's do not use the OSCON caps as they cause the LM6171's to oscillate like mad 
	

	
	
		
		

		
		
	


	




 I fitted the OSCON's earlier and fired the amp up to be presented with a high pitched squeal coming through the headphones and a very very hot transistor which burnt the end of my finger.

 I spoke to David and the LM6171 datasheet does say that low ESR (low impedance) caps can cause the LM6171's to oscillate. I removed them and fitted standard 85c caps and all's back to normal._

 

Mike - I presume you mean don't use OSCON's as output coupling capacitors? I've got OSCON's which I intend to use in the rail splitter circuit (C3 and C5) but that shouldn't affect the stability of the LM6171 - should it?


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Mike - I presume you mean don't use OSCON's as output coupling capacitors? I've got OSCON's which I intend to use in the rail splitter circuit (C3 and C5) but that shouldn't affect the stability of the LM6171 - should it?_

 

No, I mean don't use them in the rail splitter (C3 / C5) if you do you'll get a high pitched whine and TR4 will start to go into meltdown. The OSCON's are great caps if you're using FET opamps but their low impedance causes the LM6171's to go pretty crazy 
	

	
	
		
		

		
		
	


	




 I don't know why this should be and maybe someone can shed some light on this? I tested the OSCONS in the little B-Tech amp which uses the same value caps and they were fine so they're not faulty caps and I can just assume it's something to do with their very low impedance. You can try them but if you hear a high frequency whistle then shut down immediately.... who knows, it may just be a quirk with my amp that's causing the LM6171 to oscillate but I'll wait and see if Dr. White manages to replicate the situation at his end..... thought it best to warn about this just to be on the safe side


 I'm so glad I tried them out with the LM6171's as I'd hate to think other people would have problems with the oscillation and not know it was being caused by the low impedance OSCON's. 

 Remember also that Dr. White's amp was not designed around the LM6171's and I don't think he's tried the OSCON caps with the LM6171's yet..... I'll be interested to hear if they do the same thing in his test amp.

 All the best.

 Mike.


----------



## raja

Pinkfloyd, the oscon info is very useful, and something I didn't expect would happen, perhaps David can shed some light as to why this may be taking place. Perhaps the caps are draining the on board regulation to an extent where the lm6171's are being starved. This is also interesting to know for those of us who may use high speed regulator circuits to power the amp in future. Super regulators are also sensitive to low impedence caps when they're placed too close to the output. What opamp did you have in place in ic2, during your experiment with the Oscons? A wild guess is that, if it were say a ad8065 or even ad825, the presence of oscons on the output may have caused ic2 to oscillate, which in turn caused oscillation at the lm6171's...... It may be safer to stick with the lf351 in the ic2 position if using lm6171, or something 'moderatley fast' such as opa627's.......... The lm6171 must be far more power supply sensitive and power draining than the fast - but slow in comparison - ad8065. 
	

	
	
		
		

		
		
	


	




 bye
 Raja


----------



## Alick

Just realised my question was a tad silly as the OSCON's are polarised and output cap's aren't. Thanks for the info - saved me burning my finger. For what it's worth, I'm planning to use a TL071 for the rail splitter. 

 BTW, Rapid just lost some browny points with me. I just checked through my order in detail and the BD140's were out of stock - despite the web-site allowing me to order them. Of course, they're listed as OOS now. Damn.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Just realised my question was a tad silly as the OSCON's are polarised and output cap's aren't. Thanks for the info - saved me burning my finger. For what it's worth, I'm planning to use a TL071 for the rail splitter._

 

I'm glad it was my finger I put in to see where the heat was coming from and not my more sensitive probe 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *Alick* 
_BTW, Rapid just lost some browny points with me. I just checked through my order in detail and the BD140's were out of stock - despite the web-site allowing me to order them. Of course, they're listed as OOS now. Damn._

 

I knew that as I phoned my order through and I knew there was a reason I ordered 6 BD140's instead of 3 
	

	
	
		
		

		
		
	


	




 I got them from Maplins. I'll shove them in a Jiffy bag and you'll have them for Saturday morning.

 All the best.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Pinkfloyd, the oscon info is very useful, and something I didn't expect would happen, perhaps David can shed some light as to why this may be taking place. Perhaps the caps are draining the on board regulation to an extent where the lm6171's are being starved. This is also interesting to know for those of us who may use high speed regulator circuits to power the amp in future. Super regulators are also sensitive to low impedence caps when they're placed too close to the output. What opamp did you have in place in ic2, during your experiment with the Oscons? A wild guess is that, if it were say a ad8065 or even ad825, the presence of oscons on the output may have caused ic2 to oscillate, which in turn caused oscillation at the lm6171's...... It may be safer to stick with the lf351 in the ic2 position if using lm6171, or something 'moderatley fast' such as opa627's.......... The lm6171 must be far more power supply sensitive and power draining than the fast - but slow in comparison - ad8065. 
	

	
	
		
		

		
		
	


	




 bye
 Raja_

 

Hi Raja,

 Ok here's what happened..... I fitted the OSCON's into place and also rolled in an AD825 to try out at the same time. I powered the amp up to be greeted by a high frequency pitch (through the phones) and the smell of hot component. Switched off and assumed I must have soldered the AD825 onto the browndog less than satisfactorily so I replaced it with the AD8065 which I knew worked. Powered up again and the same thing...... this time I put my finger on the components and felt that Tr4 was roasting hot (blister to prove it!) Being totally stupid and not getting the message, I put an OPA134 into IC2.... same thing again. I finally removed the OSCON caps and replaced them with ELNA's and everything was back to normal firing on all four cylinders again.

 David is going to try to replicate this at his end so we should know the cause pretty soon...... he did mention that he had read somewhere that the LM6171's don't get on too well with low impedance caps.

 No harm done but I am really glad I came across this as I know a lot of people favour the OSCON caps and wouldn't like them to end up with oscillating LM6171's. I've got the AD8605 back in IC2 and a couple of ELNA caps in C3 and C5 and all is well  

 I'm sure the OSCON's would sound great in the amps original guise with OPA627's and no output caps but for some reason they don't get along with the LM6171.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *PinkFloyd* 
_Holy cornetto Batman! I've replaced the 47k input resistors with 10K input resistors, as suggested, and they'll be staying put that's for sure! Maybe it's something to do with the amp burning in or maybe it's due to the 10K resistors I dunno but one thing's for sure...... it sounds "even" better since swapping the 47K's for the 10K's...... there is so much clarity it's as though you're listening to seriously good equipment in the dead of night with no ambient noise..... just pure spine tingling, goose bump inducing crystal clear sound.

 It's hard to find anything these days that will make the hairs on the back of my neck stand up (the remaining few!) but this little amp is managing to excite them with quite worrying regularity 
	

	
	
		
		

		
		
	


	




 I honestly think it's time to weld the bonnet shut..... well, I may experiment with different types of output caps first  but, no, seriously this little amp has blown me away and I haven't listened to so much music, and enjoyed every moment of it, for a "very" long time. The way the WNA presents the music is absolutely addictive and I just can't prise myself away from it...... 

 To heck with the technicalities of output caps, resistors or any other components..... this amp presents your ears with sweet music and it's the first hi-fi component in years that has managed to draw me into the music..... it's a beauty.

 Mike.

 PS: The cymbals and hi hat on the Buddy Rich album "Tuff Dude" track 3 '2nd Avenue blue' sound anything "but" splashy or bright...... in fact, they are pretty true to the event and realistic sounding and the starts and stops of the rimshots are rapid and sound like they should "thwack!!" (followed by an inky black silence) as opposed to thwack.k.k.k.k.k.k.shhhhhh I can detect from the recording that Buddy had tuned his snare for speed....... anyways I won't ramble on about drumming but can assure you that (in this application) output caps don't necessarily equate to "spashy" cymbals 

 All the best.

 Mike._

 

Whoops! All is not as it first seemed with the change from 47K to 10K input resistors. After prolonged listening, in particular listening to my favourite recordings, I found the sound slightly dry and congested and the soundstage was more closed in...... reverting back to the 47K input resistors opened things up again and the Buddy Rich album sounded even better.

 The 10K input resistor "may" work for some people but, for me, there's definitely a lot more performance with the 47K input resistor in the circuit. I really should have listened to my favourite recordings before commenting on the 10K resistor but these things happen and, as it stands, the 47K works best in my setup.


----------



## Nigel

Really looking forward to hearing this amp Pinkie, can't wait.

 Dear me Mike, first the Chiarra then the GSP Solo & now this!

 These British manufacturers should be buying you a few drinks for putting their amps in the picture mate.

 You must be confident it plays music because if it doesn't outperform the Chiarra I'll say so. 

 Best wishes,

 Nigel


----------



## jnewman

Well, now I really have to make one of these. I've never put together specifically a headphone amp before, but I've done a bit of electronics work and am pretty good with a soldering iron.... so we'll see. I guess I'll start ordering parts. Just making sure... it IS the headphone amplifier PCB from page 17 of the wmaudio.com catalog for 30GBP, right? Also, there was a bit in there about batteries as a good power source - is there any information on this with specific relation to this amp, as well as information on a charging circuit for it?


----------



## PinkFloyd

Quote:


  Originally Posted by *Nigel* 
_Really looking forward to hearing this amp Pinkie, can't wait._

 

Hi Nigel,

 I will send my amp down to you within the next 10 days so you can have a bloomin' good listen to it.

  Quote:


  Originally Posted by *Nigel* 
_Dear me Mike, first the Chiarra then the GSP Solo & now this!_

 

Have you forgotten the X-Can V2, the B-Tech 928, the Creek OBH-11SE and the Mint in a Hammond? 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *Nigel* 
_These British manufacturers should be buying you a few drinks for putting their amps in the picture mate._

 

Not at all mate, it's what Head-Fi is all about and it's a great hobby... that's enough for me 
	

	
	
		
		

		
		
	


	


 

  Quote:


  Originally Posted by *Nigel* 
_You must be confident it plays music because if it doesn't outperform the Chiarra I'll say so._

 

I know.

  Quote:


  Originally Posted by *Nigel* 
_Best wishes,

 Nigel_


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Well, now I really have to make one of these. I've never put together specifically a headphone amp before, but I've done a bit of electronics work and am pretty good with a soldering iron.... so we'll see. One question: is www.wnaudio.com the same White Noise Audio who makes the board, and is that where you ordered it?_

 

Yes, that's the correct website. Go to the contact page and drop Dr. White a line from there. If you look at the catalogue PDF you'll see the current price list.

 It's actually a pretty straightforward kit to build and has got bags of potential as you can see! I'll be putting all the mods that Dr. White has performed over the past few weeks on my website but I'm sure he will have incorporated them into the construction manual by now..... if not, and in the meantime, you can find all the mods in this thread.

 All the best with building it up 

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *bpribadi* 
_Hi Mike, thanks for sharing! I would like to try the LM6171, eventhough using output caps is against the philosophy for good audio circuits. (What the heck 
	

	
	
		
		

		
			





 )

 Do you mind to share your circuit diagram? If it is not propietary 
	

	
	
		
		

		
		
	


	




 Thanks!
 Bram_

 

Hi Bram,

 It's not "my" circuit diagram, the amp was designed by Dr. David White of White Noise Audio. He supplies a schematic diagram with the PCB, which is very good of him, but I'm not too sure if he would appreciate people circulating his diagrams without his permission so I'm afraid I can't share with you. 

 You can always contact him direct from the contact link at http://www.wnaudio.com/ and ask him for yourself.

 Mike.


----------



## Alick

Quote:


 I knew that as I phoned my order through and I knew there was a reason I ordered 6 BD140's instead of 3 I got them from Maplins. I'll shove them in a Jiffy bag and you'll have them for Saturday morning. 
 

What can I say? (/Speechless)
  Quote:


 I'll be putting all the mods that Dr. White has performed over the past few weeks on my website but I'm sure he will have incorporated them into the construction manual by now... 
 

He has - the version I got has a section at the end for "tweakers" which details the changes required for the LM6171 and the increased class A biasing.

 Cheers

 Alick


----------



## damitamit

just like to say, great thread pinkfloyd!!!

 im definately going to be ordering a pcb very soon.

 if it is as you say and sounds better than the chiarra (heard WordWorths 2 box one at the UK meet) ill be really really pleased, as the chiarra sounded pretty damn great with the hd650s!

 been looking for a amp around the £100 mark to replace my ra-1 clone for my hd600s for a few weeks now. this seems like the one..


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_What can I say? (/Speechless)_

 

Nothing worse than being short of a few key components at the weekend...... I know the feeling 
	

	
	
		
		

		
		
	


	




 They're in the local pillar box so will be with you for Saturday morning. No need to say anything Alick, just have fun putting the amp together 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *Alick* 
_He has - the version I got has a section at the end for "tweakers" which details the changes required for the LM6171 and the increased class A biasing._

 

Excellent! that's superb and just goes to show that traditional service and customer satisfaction is still paramount to WNA..... top class! 

 I'm putting together a small guide at http://www.rock-grotto.co.uk/whitenoiseaudio.htm which will soon be fully operational......... I've yet to write the review and there are a few loose ends to tidy up but I should have it all completed shortly.

 Alick[/QUOTE]


----------



## guzzler

Quote:


 Hope that answered your question Guzzler. 
 

 seems reasonable enough to me... 
	

	
	
		
		

		
		
	


	




 edit, about Rapid: I've used them for about 3 years, and the website is a very new thing. I would still recommend getting their catalog and ordering by phone, call 01206 751166 to order catalogs and parts. They'll tell you directly if the parts aren't in stock

 g


----------



## raja

Hi Pinkfloyd,

 I guess the 10k resitors work when the source component has a low enough z out to drive the impedence.......... Like you said not all compnents these days do. I have a tube output stage modded cd player which has an output impedence of around 100 ohms, and that drives my passive 10k attenuator very well, the same cannot be said about some of the other sources I sometimes use, with which the sound becomes thin and bass shy. A case for modding output stages in source components perhaps?

 Thanks
 Raja


----------



## jnewman

Alright, so a couple more questions. I think I've put together a pretty complete parts list, and everything's looking good. Are the electrolytic capacitors you use the aluminum type? Who makes the LM6171 op-amp, and where can I order them (I can't find it in the Mouser catalog I'm going to be ordering from)? What guage wiring do you use for internal connections? It looks like you didn't use the plug/sockets for input output, just put the wires directly through the board, is that right? Finally, the big black fins in your pictures are heatsinks on the transistors, aren't they? Where can you get them and do you recommend them (I know Dr. White says they're optional)?

 Thanks... sorry for all the questions.


----------



## Alick

Mike's not around so I'll try to answer. National Semiconductors make the LM6171 - there's a list of TX distributors here. However, you'll need to get the PCB from WNA and they can supply all the parts, including the LM6171's. We got our parts from UK distributors, but any general electronics component distributor on your side should be able to supply everything except the PCB. The electrolytics used as output coupling capacitors are non-polar electrolytics and the PSU rail splitter ones are bog-standard 85C jobs - don't use the aluminium low-impedance ones with the LM6171's as that appeared to cause the op-amps to oscillate. Looks like Mike used general purpose hook-up/equipment wire (16/0.2mm or 24/0.2mm?) - anything should do as long as it's reasonably beefy. I'm using single core as it's all I could lay my hands on at the time. Hope this helps.

 Alick


----------



## jnewman

Hmm... I can find a number of kinds of non-polar or bi-polar capacitors, but the only ones that are called "electrolytic" are "aluminum electrolytic" and seem to come in both low-impedance and standard flavors... is there somewhere else I should be looking?

 The catalog I'm using has headings for:
 Aluminum
 Tantalum
 Silicon
 Film
 Ceramic

 What exactly IS an electrolytic capacitor?

 Thanks - I haven't had a whole lot of experience with components selected for signal quality, so I'm not sure what the difference is between all the different types. (I do understand the polar/nonpolar/bipolar bit though).


----------



## Alick

This page  gives a reasonable summary of how the various capacitor types are constructed and used. It doesn't mention non-polarised electrolytics - they are a reasonably recent innovation. Basically, electrolytics provide a higher capacitance value by volume compared to other capacitor types and the previous disadvantage (that they were polarised) has been overcome with the introduction of the non-polarised versions. Those which are advertised as solid aluminium have advantages for use in audio circuits (including high frequency performance and longer life) but were found to be unsuitable for use in this circuit with the LM6171's.

 Check the suppliers in the DIY forum big list for suppliers in your area.


----------



## PinkFloyd

That's the second WNA (in the larger enclosure) completed and, before I do the final fit and finish, I'm trying out a selection of FET opamps in it without input or output capacitors.

 At the moment I've got AD8610's on board and an OPA134 in the rail splitter and the sound is pretty damned excellent. My OPA 627's arrived today so I'll swap the OPA134 for an OPA627 later on. I'll experiment with a combination of opamps and see how these compare to the LM6171's in the other amp. These AD8610's certainly do sound very good........











 More pics HERE


----------



## Alick

Another neat job Mike - and I haven't even started yet. (Tonight, hopefully). I notice you've put load resistors on the switched side of the jack - good idea, I was planning to do the same. 
  Quote:


 I'm trying out a selection of FET opamps in it without input or output capacitors. 
 

The beauty of socketed op-amps. Let us know how the trials go.


----------



## jnewman

I'm getting geared up to make the purchases to put this little baby together, and thank you all for answering my stupid questions. One last (non-stupid) question. It won't impact whether or not I do this amp, because the price can't be beat, but I noticed someone asking earlier with no responses - anyone want to compare it to the PPA (I suppose a low/middlish one, obviously not a $500 maxed out one)? Thanks - I can't wait, haven't had my hands dirty with electronics in far too long.


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_I'm getting geared up to make the purchases to put this little baby together, and thank you all for answering my stupid questions. One last (non-stupid) question. It won't impact whether or not I do this amp, because the price can't be beat, but I noticed someone asking earlier with no responses - anyone want to compare it to the PPA (I suppose a low/middlish one, obviously not a $500 maxed out one)? Thanks - I can't wait, haven't had my hands dirty with electronics in far too long._

 

Have fun building the amp 
	

	
	
		
		

		
		
	


	




 I'm listening to a second WNA I built with AD8610's and it sounds "bl**dy" good so if you don't want the hassle of sourcing and implimenting output caps then that would be an alternative road to go down..... the AD8610's are more expensive than the LM6171's and you'll need to buy them on Browndog adaptors (or mount them yourself) I'll do a comparison between the 2 amps later on to see if there's a lot of difference between an LM6171 WNA and an AD8610 WNA.

 I can't compare it to the PPA as I don't have a PPA but I'm sure someone will get round to comparing the two 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.

 PS: if you use the AD8610 you can also use the OSCON SP caps


----------



## StevieDvd

Before you do a comparison between them make sure you put some Rainbow stickytape in the little one 
	

	
	
		
		

		
			





 Looks like they are coming on a treat. 
	

	
	
		
		

		
		
	


	




 Steve


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Before you do a comparison between them make sure you put some Rainbow stickytape in the little one 
	

	
	
		
		

		
		
	


	




 Looks like they are coming on a treat. 
	

	
	
		
		

		
		
	


	




 Steve_

 

Hi Steve,

 It sure is coming on a treat 
	

	
	
		
		

		
		
	


	




 All I'm waiting for now are a couple of the ALCAP caps from Cricklewood electronics in order that I can fit the LM6171's into the amp. I tried Nitai non polars, Bennic Bi polars and an Evox polyprop but none of them can match the 25uF ALCAP for sheer bass grunt and energy.. dunno why but the LM6171's perform incredibly with the ALCAPS.

 I thought, whilst I'm waiting for the ALCAPS, that I'd try the FET opamps but initial comparisons between the LM6171 WNA and the AD8610 WNA show the AD8610's to possess a very laid back sound.... nice and easy going.... as soon as you switch to the LM6171 WNA there's bags more punch, truckloads more detail and the bass delivery is absolutely Subterranean. At first I thought there must have been something wrong with the AD8610 WNA but, no, the LM6171 sure does sound a lot lot better and the difference isn't "subtle" it really reaches out and grabs you by the balls.

 If you prefer a more laid back easy listen then the AD8610 might be worth considering but if you like your music to take you on a roller coaster ride, warts and all, then the LM6171 is the way to go.

 I tried the AD8065 also but it sounded even more laid back than the AD8610 and was very bass shy indeed....... I whipped it out after just 1 hour in the circuit....... I really did expect it to sound a lot better 

 Raja suggested I try the OPA627 in IC2 and I'm glad he did... I've used an OPA627BP, it certainly does improve the midrange a tad and it'll remain plugged in  

 All the best.

 Mike.


----------



## raja

Kudos Pinkfloyd, for trying both types of opamp, my take is that with the increased slew rate of the lm chip, you'll have far more seperation and space between everything The ad chip will sound a little more raw in it's presentation of individual instruments if you focus on their texture, a tad more nuances on strings, because of the omission of the output caps, which in my experience remove just a fine bit of air from everything, although you do have to listen hard to individual sounds to notice. So I guess it's just a question of taste.......

 Got my LM6171's today will try them soon!





 PS I guess you may be in a bit of a shock with the opa's as I don't think they come remotley close to the ad chips mentioned, especially if you compare price performance ratios. They sound flatter and less extended in comparison, you also get less air and 'emotion' thru them. Still they are some peoples favourite opamp......

 Thanks
 Raja


 EDIT:
 PS As I typed this Mike had already tried the chips mentioned and posted his findings.............


----------



## StevieDvd

I think you should fit a lock to my case as all this talk of trying different opamps might get me tinkering (really I don't think so the chances of me screwing up are too great 
	

	
	
		
		

		
		
	


	




 ).

 Laid back versus being grabbed by the balls? We are still discussing Headphone Amps aren't we! 'Laid back' - sounds like the wimp choice (pun intended), bring on the detail.

 "I tried Nitai non polars, Bennic Bi polars and an Evox polyprop ..." you may as well be speaking Russian I just hope the final choice ones are a nice colour.

 I can't wait to try it - on the one hand I want to wait to hear how it sounds with the sources I have - on the other hand my wallet is itching for a new CD player to do it justice. I guess I should learn to be patient it's usually cheaper and wife friendly.

 Best regards

 Steve


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Kudos Pinkfloyd, for trying both types of opamp, my take is that with the increased slew rate of the lm chip, you'll have far more seperation and space between everything The ad chip will sound a little more raw in it's presentation of individual instruments if you focus on their texture, a tad more nuances on strings, because of the omission of the output caps, which in my experience remove just a fine bit of air from everything, although you do have to listen hard to individual sounds to notice. So I guess it's just a question of taste.......


 Got my LM6171's today will try them soon!





 PS I guess you may be in a bit of a shock with the opa's as I don't think they come remotley close to the ad chips mentioned, especially if you compare price performance ratios. They sound flatter and less extended in comparison, you also get less air and 'emotion' thru them. Still they are some peoples favourite opamp......

 Thanks
 Raja


 EDIT:
 PS As I typed this Mike had already tried the chips mentioned and posted his findings............._

 

Hi Raj,

 It's the LM6171 (with output caps) that sounds raw and organic and the AD8610 sounds pretty rose tinted and mushy in comparison. It's a very nice easy listen with the AD8610 and to compare the two I would have to call the AD8610 "mantovani elevator music" and the LM6171 "laser show music" silly comparison I know 
	

	
	
		
		

		
		
	


	




 There's a place for laid back and a place for up front but I feel, in general, the LM6171 presents the music more realistically. 

 I think these ALCAPS may have broken some rules here and you must have a listen to the LM6171's with 25uF 50V ALCAP bi polars. As I say, the bass extends to subterranean depths and the energy and slam is spine tingly good 

 I also tried some polyprops, some Nitai non polars etc. and none of them made such an impact as the ALCAPS.... David reckons the bass grunt may be due to the 25uF capacitance.... 

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_PS As I typed this Mike had already tried the chips mentioned and posted his findings............._

 

Only tried in the rail splitter Raja...... I'm sticking with the LM6171's in IC1 I know what the 627's sound like having lived with them in the Chiarra


----------



## raja

Hi Pinkfloyd,

 What is the value of the electrolytics you are using after the rail splitter?

 Thanks
 Raja


----------



## philodox

S_Dedalus responded to my question in a PM, thought you might be interested:

 "is there any way you could set up a mount for the caps so that you could swap them out easily for cap rolling? [kind of in the same way as people do with their opamps]"

 Try using sip sockets


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi Pinkfloyd,

 What is the value of the electrolytics you are using after the rail splitter?

 Thanks
 Raja_

 

35v 100uF


----------



## PinkFloyd

Have you started building your WNA yet Alick? If so, how's it going?


 Mike.


----------



## Alick

Mike - I think your post crossed with my PM in the ether, but if anyone else is interested, all the hardware's complete, the PCB is 90% assembled and just needs finishing and hooking up to the controls. Then I can power-up and watch for blue flashes... I'm hopefully on schedule for some weekend listening. Oh - and I'm really enjoying myself. 
	

	
	
		
		

		
		
	


	




 Alick


----------



## PinkFloyd

Dr. White has tested the OSCON caps in his lab and couldn't replicate the oscillation I experienced when he tried them in his testbed amp.

 I quote his findings: "I've just been experimenting with OSCONs in the rail splitter. I used two 68uF 16V OSCON SA/SCs IC2=TL071 and IC1=LM6171 and I couldn't provoke instability no matter what input signal or load impedance that I used. There was no trace of overshoot or ringing on 10kHz square viewed on my oscilloscope. Amp was unconditionally stable. I suspect that it might be your power supply causing the problem as LM317 voltage regulators are known to dislike very low impedance caps on their outputs.

 Mike.


----------



## jnewman

Alright, so I've just read through all the interesting looking topics on about the first forty pages of the DIY forum to get a bit more background in the audio electronics stuff before I really get started on mine (just about have the details of my order finalized with David, waiting on payment info), and I came up with another question. I would like to add a bit to this amp to make it run a wide range of headphones effectively, and I came up with a couple of options - a gain selector to lower gain for low impedence phones and buffered (current boosted) outputs. Let's see if I understand what all this would do:

 Gain selector would mostly just make it so the volume knob range was correct for both low impedence and high impedence phones.

 Buffered output would supply the extra current low-impedence phones want to draw to get their full dynamic range.

 Is that correct? If it is, would it be a good thing to do both? If so, what sort of buffers would fit well with this amp? I think I've figured out how they'd have to be wired, if I decide to do it all I'll post my updated schematic bit for anyone who wants it (after I do it and make sure it works 
	

	
	
		
		

		
		
	


	




 ).

 Thanks.

 (And I know there's that Low-Z High-Z discussion right here with this, but I want suggestions specific to the wna amp - and they didn't discuss buffers at all.)


----------



## guzzler

The WNA (along with most of the designs you see here) has a current buffer, in this case a complementary pair of transistors, so you're sorted in that respect. 

 Depending on how loud you like to listen, an amp with a gain of 4 will do you for both high and low impedance headphones. Personally, I'd set a gain of about 5 as most of the headphones you'll use for home use are (relatively) high-Z, and 5 is a nice gain level. If you're desperate for a gain switch, you'll need to check the schematic for the correct resistor: there's a junction between two resistors that leads to the inverting input on the opamp. Once you've found this, you can use a switch that will toggle between two different values of resistor to vary the gain. Make sure you keep the leads as short as possible as any noise injected here is amplified by the full gain of the amplifier

 g


----------



## jnewman

Heh, I'm so used to seeing the IC buffers that I didn't even notice/realize the transistors were there - I do know what transistors do, don't worry, so don't start taking bets about how big a boom the thing'll make when I turn it on 
	

	
	
		
		

		
		
	


	




. What I don't know, from lack of audio electronics experience, is if the transistors used can supply enough current for really low impedence phones that pull a lot of current (like Grados, which I hear can be problematic sometimes).

 Thanks again.

 Oh! And how necessary are the heatsinks Pinkie put on the transistors? I don't recall the notes David White sent me on the amp mentioning them.


----------



## Alick

I should finish building my WNA this week and I'll be driving SR-80's so I'll let you know. I don't anticipate any problems though. According to Davids notes (from memory), the heastsinks aren't essential when using the wall wart, but they are advised if you use a better rated PSU. I fitted them as they are penny-piece parts and they aren't eating any hay...


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_I think you should fit a lock to my case as all this talk of trying different opamps might get me tinkering (really I don't think so the chances of me screwing up are too great 
	

	
	
		
		

		
			





 ).

 Laid back versus being grabbed by the balls? We are still discussing Headphone Amps aren't we! 'Laid back' - sounds like the wimp choice (pun intended), bring on the detail.

 "I tried Nitai non polars, Bennic Bi polars and an Evox polyprop ..." you may as well be speaking Russian I just hope the final choice ones are a nice colour.

 I can't wait to try it - on the one hand I want to wait to hear how it sounds with the sources I have - on the other hand my wallet is itching for a new CD player to do it justice. I guess I should learn to be patient it's usually cheaper and wife friendly.

 Best regards

 Steve_

 

Hi Steve,

 The caps arrived and that's the amp completed. I'll leave it on test overnight and will probably send it you either tomorrow or the following day


----------



## Alick

Nice job - again. My 10R's arrived from Rapid today 
	

	
	
		
		

		
		
	


	




, so it's back to the soldering iron...


----------



## raja

Hi,

 I emailed David yesterday with a few questions, one of my questions was with regards to a schematic for a circuit to nullify the need of an ouput cap with opamps such as the lm6171. I aksed for a circuit to inject a small voltage into the input of the opamp, as David had pointed out in one of Pinkfloyd's posts. Should the ciruict be practical and simple enough to build, it will be well worth it. Those of us who are trying/keeping the lm6171's in place, may want to keep those chassis lids unwelded for now, unless ofcourse you are in some kind of audio nirvana already.

 Thanks
 Raja


----------



## guzzler

Quote:


  Originally Posted by *jnewman* 
_is if the transistors used can supply enough current for really low impedence phones that pull a lot of current (like Grados, which I hear can be problematic sometimes)._

 

yep, the pair used here is BD139/BD149 rated 1.5A each, and 8W. If you put all that into your headphones, your ears will explode just before the phones do 
	

	
	
		
		

		
		
	


	




 As for the heatsinks, they're probably not strictly necessary as they are both in TO220 packages, and for the small current drawn by headphones, they'll easily dissipate the power, but it's worth doing it anyway; better safe than sorry after all.

 g


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Steve,

 The caps arrived and that's the amp completed. I'll leave it on test overnight and will probably send it you either tomorrow or the following day_

 

Hi Mike, 
 Publicly, I'm typing - That's great to hear of course and no hurry sending it out until you are happy with it. 
	

	
	
		
		

		
		
	


	




 Secretly thinking - Whooooo hope he sends it tomorrow, can't wait to try it. Very impressed with the colourful wiring - is that what makes an amp bright? 
	

	
	
		
		

		
		
	


	




 Cheers

 Steve


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Nice job - again. My 10R's arrived from Rapid today 
	

	
	
		
		

		
		
	


	




, so it's back to the soldering iron..._

 

Ah that's excellent Alick  Did you manage to source some 100R's? If not I'll send you a few 75R's for the headphone socket dummy load.

 Mike.


----------



## Nisbeth

Quote:


  Originally Posted by *StevieDvd* 
_Very impressed with the colourful wiring - is that what makes an amp bright? 
	

	
	
		
		

		
		
	


	




 Cheers

 Steve_

 

No, it colours the sound 
	

	
	
		
		

		
		
	


	







 Let us know of your impressions when you receive the amp 
	

	
	
		
		

		
		
	


	





 /U.


----------



## StevieDvd

Ahhh, so if the sound is not as cloured as I expect then I put some go fast stripes on the box. I'll not be touching the hallowed inside of the case until I've got a Diploma for tweaking fom the Pinkfloyd School of Rock.

 Be assured that I will pass on my humble assessment bearing in mind the only amp I've ever used is a cheapie cmoy (no offense intended to anyone especially Mr Chu Moy 
	

	
	
		
		

		
		
	


	




 deep respect whilst going off on a Tangent 
	

	
	
		
		

		
		
	


	




 ). So expect terms like great, super, wonderful rather than ' a bit sibilant' cos I don't know what that means.

 Please be as patient for the feedback as I've been patient waiting for the amp - hurry up Mr Postman!!!

 Regards

 Steve


----------



## jnewman

Yikes, yeah, gotcha. 1.5A is PLENTY, and 8W will drive smallish speakers. Heh. I guess that answers my question. Thanks!

 Now I just have to find a way around the fact that a bank transfer to Mr. White in the amount of 37 pounds would cost me $47 PLUS the 37 pounds(grumble). I guess I'll be doing it the slow (mail) way.


  Quote:


  Originally Posted by *guzzler* 
_yep, the pair used here is BD139/BD149 rated 1.5A each, and 8W. If you put all that into your headphones, your ears will explode just before the phones do 
	

	
	
		
		

		
		
	


	




 As for the heatsinks, they're probably not strictly necessary as they are both in TO220 packages, and for the small current drawn by headphones, they'll easily dissipate the power, but it's worth doing it anyway; better safe than sorry after all.

 g_


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Yikes, yeah, gotcha. 1.5A is PLENTY, and 8W will drive smallish speakers. Heh. I guess that answers my question. Thanks!

 Now I just have to find a way around the fact that a bank transfer to Mr. White in the amount of 37 pounds would cost me $47 PLUS the 37 pounds(grumble). I guess I'll be doing it the slow (mail) way._

 

Hows about paypaling someone here and getting them to send a cheque to WNA? Problem solved.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Ahhh, so if the sound is not as cloured as I expect then I put some go fast stripes on the box. I'll not be touching the hallowed inside of the case until I've got a Diploma for tweaking fom the Pinkfloyd School of Rock._

 

There's nothing to tweak Steve unless you want to try out the AD8610's etc.?

  Quote:


  Originally Posted by *StevieDvd* 
_Be assured that I will pass on my humble assessment bearing in mind the only amp I've ever used is a cheapie cmoy (no offense intended to anyone especially Mr Chu Moy 
	

	
	
		
		

		
		
	


	




 deep respect whilst going off on a Tangent 
	

	
	
		
		

		
		
	


	




 ). So expect terms like great, super, wonderful rather than ' a bit sibilant' cos I don't know what that means._

 

Look forward to hearing your comments!


  Quote:


  Originally Posted by *StevieDvd* 
_Please be as patient for the feedback as I've been patient waiting for the amp - hurry up Mr Postman!!!_

 

Blimey it's only been a week 
	

	
	
		
		

		
		
	


	




 I'll def send it tomorrow 
	

	
	
		
		

		
		
	


	





 Regards

 Steve[/QUOTE]


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_Hows about paypaling someone here and getting them to send a cheque to WNA? Problem solved._

 

That's really a very good idea... would you be willing to do it for me? or anyone else? I can do the direct bank transfer type of paypal transaction, so it doesn't need to be someone with the fancy kind of paypal account.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_There's nothing to tweak Steve unless you want to try out the AD8610's etc.?_

 

Nooooo I'm too scared of the damage I'd do.

  Quote:


 Look forward to hearing your comments! 
 

I look forward to commenting on my hearing. 
	

	
	
		
		

		
		
	


	



  Quote:


 Blimey it's only been a week 
	

	
	
		
		

		
		
	


	




 I'll def send it tomorrow 
	

	
	
		
		

		
		
	


	



 

I was using a bit of poetic license - not serious.

 Regards

 Steve[/QUOTE][/QUOTE]


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Nooooo I'm too scared of the damage I'd do.


 I look forward to commenting on my hearing. 
	

	
	
		
		

		
		
	


	




 I was using a bit of poetic license - not serious.

 Regards

 Steve_

 

It'll be with you before midday tomorrow


----------



## StevieDvd

I'll confirm safe receipt and first plugin test soonest.

 Work permitting I'll be able to have a good listen tomorrow evening.

 Thanks

 Steve


----------



## jnewman

Here's a question in the vein of my earlier ones... I haven't really been able to find any feedback on them, how good do the BD139/140 transistors sound? Would it be an upgrade to put in one of the diamond buffer types?

 I haven't even built the thing yet and I'm already obsessed with tweaking it.


----------



## guzzler

Quote:


  Originally Posted by *jnewman* 
_Here's a question in the vein of my earlier ones... I haven't really been able to find any feedback on them, how good do the BD139/140 transistors sound? Would it be an upgrade to put in one of the diamond buffer types?_

 

 Probably not an upgrade, and you'd have to seriously rearrange the board layout to take a "diamond buffer". There might, however, be higher grade transistors available, certainly for the SDS amp, the Hitachi MOSFETs were preferred. You'd have to contact Dr. White to see if there were any other suitable transistors

 g


----------



## Nisbeth

Quote:


  Originally Posted by *guzzler* 
_...you'd have to seriously rearrange the board layout to take a "diamond buffer"...._

 

I think the question was if the transistors used in the diamond buffer could be used instead of the BD139/140 
	

	
	
		
		

		
			






 /U.


----------



## raja

Hi,

 I think the 139/140's give quite a refined sound in this circuit, it's not harsh by any means, overall you feel you are hearing quite an accurate depiction of the source. With regards to the opamps used, I do remember that with opa627's in place if you crank up the volume you can certainly hear the artifacts of feedback, though they certainly sound very refined at normal listening levels. Overall you will not be able to find a more reasonably priced setup for your headphones. Plus the support of this amp has grown incredibly since pinkfloyd posted here, so new tweaks and other info should always be readily accessible. The reason I talk of sibilance etc, is that with modern equipment, feedback has become a way of making everything linear, especially where opamps are concerned. To say that feedback only affects amplified music in a positive way is a gross mistake. Some of the artifacts of feedback are good and others are bad. One thing I did find in this amp so far is that with the lm6171's things sound far more natural and without the sharpness. Whether or not that is down to the coupling caps on the output we'll have to see, when the circuit becomes available to remove them.
 I often find that now the excitment I used to feel when listening to equipment for the first time is not so overwhelming. Before I had only read statments about SS equipment, opamps and tubes etc, the classic stereotyping of each technology etc. Eventually once you've built a few circuits tried a few tweaks, you find that everything has it's own sonic signature, some for the better and some for the worse..........

 Thanks
 Raja


----------



## jnewman

Quote:


  Originally Posted by *guzzler* 
_you'd have to seriously rearrange the board layout to take a "diamond buffer"._

 

Eh, I was thinking that if I tried it I'd use very short silver leads and mount them separately so that there wouldn't be any rearrangements necessary. I understand that the circuit would have to be changed a bit as it has different inputs from the transistor.

  Quote:


  Originally Posted by *Nisbeth* 
_I think the question was if the transistors used in the diamond buffer could be used instead of the BD139/140 
	

	
	
		
		

		
		
	


	


_

 

Nah... I did actually mean the diamond buffers. I just don't know enough about the diamond buffers to know if it's really feasible.

 Raja - thanks, good info.


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi,

 I think the 139/140's give quite a refined sound in this circuit, it's not harsh by any means, overall you feel you are hearing quite an accurate depiction of the source. With regards to the opamps used, I do remember that with opa627's in place if you crank up the volume you can certainly hear the artifacts of feedback, though they certainly sound very refined at normal listening levels. Overall you will not be able to find a more reasonably priced setup for your headphones. Plus the support of this amp has grown incredibly since pinkfloyd posted here, so new tweaks and other info should always be readily accessible. The reason I talk of sibilance etc, is that with modern equipment, feedback has become a way of making everything linear, especially where opamps are concerned. To say that feedback only affects amplified music in a positive way is a gross mistake. Some of the artifacts of feedback are good and others are bad. One thing I did find in this amp so far is that with the lm6171's things sound far more natural and without the sharpness. Whether or not that is down to the coupling caps on the output we'll have to see, when the circuit becomes available to remove them.
 I often find that now the excitment I used to feel when listening to equipment for the first time is not so overwhelming. Before I had only read statments about SS equipment, opamps and tubes etc, the classic stereotyping of each technology etc. Eventually once you've built a few circuits tried a few tweaks, you find that everything has it's own sonic signature, some for the better and some for the worse..........

 Thanks
 Raja_

 

Hi Raja,

 I take it from what you have said that the LM6171's are an improvement? May I ask what output caps you are using? I'm using non polar ALCAP electrolytics and the sound is just so organic and natural (I realise people favour polypropelynes but these ALCAPS just just so natural IMO) 

 You're certainly very laid back with your opinions and I like that  Taking the law of diminishing returns into account I would class the LM6171 as a Mammoth improvement over the stock OPA627 kit......... how would you class it?

 regards

 Mike.







 ke.


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Eh, I was thinking that if I tried it I'd use very short silver leads and mount them separately so that there wouldn't be any rearrangements necessary. I understand that the circuit would have to be changed a bit as it has different inputs from the transistor.



 Nah... I did actually mean the diamond buffers. I just don't know enough about the diamond buffers to know if it's really feasible.

 Raja - thanks, good info._

 

Hi jnewman..

 I'd be inclined to take receipt of the PCB and schematics first.... try the amp out "as is" and if you feel it needs tweaking then go on from there.


 There really is no need to try to improve it as it sounds so good. Try it as it comes you may be in for a surprise 


 mIke.


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_Hi jnewman..

 I'd be inclined to take receipt of the PCB and schematics first.... try the amp out "as is" and if you feel it needs tweaking then go on from there.


 There really is no need to try to improve it as it sounds so good. Try it as it comes you may be in for a surprise 


 mIke._

 

Oh, I won't be doing any of that stuff just yet, I'm just getting very curious about what I may be able to mess with once I get it working. I haven't done this specifically with DIY audio equipment before, but I am an obsessive tweaker and messer-with 
	

	
	
		
		

		
		
	


	




.

 Jimmy.


----------



## raja

Hi Mike,

 I would say that the lm6171's are an improvement in 2 departments given my present listening situation. The first is seperation of the sound stage, the second is the reduction in sharp edge you can hear with other opamps. I tried electrolytic bipolars, and found them to be very smooth, but there was a definate rolling off - the hf info. I didn't mind the hf being rolled off to this extent but the only problem was that with my loudspeakers the cymbals began to sound very recessed (it was as if the sound could not leave the tweeter)....

 I then tried them with polypropylene's (250v 4.7uf), these give a much brighter sound and some of the edge sharpenss came back, so I suppose it depends on personal opinion. Which is why I think the true test would come if the lm6171's were direct coupled. Although I reserve judgement until I have the buffer completley installed with my new phono stage, which is based on the classic rca tube circuit with passive riaa (no feedback). As it stands at the moment I'd say the lm6171's win in some departments but not all........ What I think is great here is the ability to use different components to tune the circuit to your personal tastes. 

 To be brutally honest my own tastes now lean towards tubes, especially in low level circuits, you get away with far less feedback and in quite a few cases with fewer passives in the signal path. However tube circuits can be very expensive in comparison to SS. Bottom line, measured distortion does not always tell you how good a circuit sounds to the ear.....

 With regards to the opa627's I guess they sound fine with headphones, as they are being used in a nearfield experience. When you have a circuit that drives an amplifier and loudspeakers however you find them to be quite flat in soundstage, meaning theat the 3d effect is minimal in comparison to opamps like the ad825. 

 I try not to harass people into believing my opinion,as I think this audio lark is so personal. My own experience has shown me that additions like CCS and other methods aren't always as apealing long term, though they do seem to grab one's attention upon first impressions......

 Thanks
 Raja


----------



## PinkFloyd

on the subject of Diamond buffers Dr. White comments:

 *"With the current headphone amp the bandwidth is ultimately limited by the emitter follower output stage, as there is no frequency compensation. This doesn't matter with medium speed opamps like the OPA134, OPA627, AD8610, etc. because they're slower than the output stage. With the LM6171 however the emitter followers do slow the amp down overall. Diamond buffers are faster than a simple emitter follower so using them would speed the amp up if you were using a LM6171 opamp. Stability might be a problem initially, but you can usually work around this. Using complementary feedback pairs rather than a simple emitter follower will also speed up the output stage too." * 

 On the subject of the BD139 / BD140 he has this to say:

* "They're pretty decent little transistors - fastish, reasonable gain, high current, high voltage, small, cheap - which is why they're popular for audio. Wouldn't think just changing the transistors will make much difference, but you never know."  *

 Regarding mosfet output devices: 

*"I just realised that a couple of people have asked about mosfet output devices. Easy enough to implement ( might even be able to use existing pcb as bjts and vfets have compatible pinouts ) and will also lead to higher overall bandwidth with LM6171 opamps. Downside is that distortion will be a tad higher and the output swing will be lower. Neither of these things may matter. You can also use complementary feedback bjt/mosfet pairs to reduce mosfet non-linearity. This all begins to sound very like my mos125 power amp design. You can actually use the mos125, with a lower than usual power supply voltage, as a headphone amplifier. A bit expensive but very good."*


----------



## Alick

Quote:


 "You can actually use the mos125, with a lower than usual power supply voltage, as a headphone amplifier. A bit expensive but very good." 
 

Don't even go there... (reaches for wallet padlock).


----------



## StevieDvd

Pinkfloyd
 --------

 Box arrived at home (before 12.00) and is calling my name, familty have instructions not to touch or open it till I get home.

 Will update you later.

 Steve


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_on the subject of Diamond buffers Dr. White comments:

 *"With the current headphone amp the bandwidth is ultimately limited by the emitter follower output stage, as there is no frequency compensation. This doesn't matter with medium speed opamps like the OPA134, OPA627, AD8610, etc. because they're slower than the output stage. With the LM6171 however the emitter followers do slow the amp down overall. Diamond buffers are faster than a simple emitter follower so using them would speed the amp up if you were using a LM6171 opamp. Stability might be a problem initially, but you can usually work around this. Using complementary feedback pairs rather than a simple emitter follower will also speed up the output stage too." * 

 On the subject of the BD139 / BD140 he has this to say:

* "They're pretty decent little transistors - fastish, reasonable gain, high current, high voltage, small, cheap - which is why they're popular for audio. Wouldn't think just changing the transistors will make much difference, but you never know."  *

 Regarding mosfet output devices: 

*"I just realised that a couple of people have asked about mosfet output devices. Easy enough to implement ( might even be able to use existing pcb as bjts and vfets have compatible pinouts ) and will also lead to higher overall bandwidth with LM6171 opamps. Downside is that distortion will be a tad higher and the output swing will be lower. Neither of these things may matter. You can also use complementary feedback bjt/mosfet pairs to reduce mosfet non-linearity. This all begins to sound very like my mos125 power amp design. You can actually use the mos125, with a lower than usual power supply voltage, as a headphone amplifier. A bit expensive but very good."*_

 


 Great info... once I get the PCB and all the stuff added in, I'll have to start messing around with things 
	

	
	
		
		

		
		
	


	




. Maybe I can work something out to make the output transistor stage socketed so I can just switch out transistors and some of the right sized fets (and maybe some fancypants buffer with short leads). Then again, once I get it built maybe I won't be able to stop listening to it long enough to change anything. Heh.

 Jimmy.


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Great info... once I get the PCB and all the stuff added in, I'll have to start messing around with things 
	

	
	
		
		

		
		
	


	




. Maybe I can work something out to make the output transistor stage socketed so I can just switch out transistors and some of the right sized fets (and maybe some fancypants buffer with short leads). Then again, once I get it built maybe I won't be able to stop listening to it long enough to change anything. Heh.

 Jimmy._

 

Sounds like you'll be having some fun experimenting Jimmy 
	

	
	
		
		

		
		
	


	




 The info that Dr. White comes up with is extremely interesting and it's great to know that he doesn't just sell the kit and that's the last you hear from him (like some kit suppliers) he's constantly trying to improve things and no question you ask him goes unanswered.... excellent stuff!

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Pinkfloyd
 --------

 Box arrived at home (before 12.00) and is calling my name, familty have instructions not to touch or open it till I get home.

 Will update you later.

 Steve_

 

Oh, that's excellent news Steve  It'll sound great straight out of the box but after a few days of use it'll sound even better once everything starts to bed in. Can't wait to hear your initial impressions.

 Mike.


----------



## jnewman

Alright. Now that my PCB is soon-to-be-on-its-way, I have a few questions about components:

 Are .1% resistors worth it over 1% resistors? It basically means $20 worth of resistors instead of $4. I'm just going to be buying enough for the project, so there is no hope of just matching 1% resistors to a closer tolerance.

 How are Xicon electrolytics? Mouser doesn't have any of the really fancy kinds and if they're pretty good I'd like to go ahead and order everything from one place. Most of Mouser's caps run +/-20% tolerances and the Xicon bipolars are 10%. Xicon also has audio-frequency and high-frequency bipolar caps up to 10microfarads, would they be better than standard ones for the output caps? Would film-types be better? Does a larger-capacitance output cap smooth the output more? Are the Wima FKP1 polyprops good?

 Sorry for all the questions - all my previous electronics work has been sort of works/doesn't work and hasn't been all that affected by small differences in the quality of components.

 Thanks,
 Jimmy.

 EDIT: I know I can assemble this stuff just fine, but I'm really curious about how exactly it works. I understand how everything works at an individual component level and how everything fits together with all the amp boards I've looked at, but I'm left with one question - what's the deal with the amplifier stage in the ground channel? Is it to drop the return signal back to line level? Is this necessary because the ground channel isn't a true ground that can completely sump any voltage/current and needs to be fairly balanced with the transmitted signal?


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Are .1% resistors worth it over 1% resistors? It basically means $20 worth of resistors instead of $4. I'm just going to be buying enough for the project, so there is no hope of just matching 1% resistors to a closer tolerance._

 

Hi Jimmy,

 What you pay for when you buy .1% resistors (over and above close tolerance) is a very low temperature coefficency. Standard 1% resistors have a temp. coefficiency of around 500ppm (parts per million) whereas .1% resistors such as the RC55Y's have a low temp. coefficiency of 15ppm. 

 You're not paying for a closer tolerance as 1% resistors can "easily" be matched using a ohmeter. what you are paying for is a lower temperature coefficient resistor which "allegedly" sound better in an audio application...... someone else may wish to elaborate on why low temperature coefficient resistors sound better but I've got to take the dog out......... 
	

	
	
		
		

		
			





 Basically....... it's not the tolerance that's the key here, it's the low temp. coefficiency. 


  Quote:


  Originally Posted by *jnewman* 
_How are Xicon electrolytics? Mouser doesn't have any of the really fancy kinds and if they're pretty good I'd like to go ahead and order everything from one place. Most of Mouser's caps run +/-20% tolerances and the Xicon bipolars are 10%. Xicon also has audio-frequency and high-frequency bipolar caps up to 10microfarads, would they be better than standard ones for the output caps? Would film-types be better? Does a larger-capacitance output cap smooth the output more? Are the Wima FKP1 polyprops good?_

 

I haven't got a clue who the best supplier in the USA is but +/- 10% sure sounds better than +/- 20%  I, personally, use 50V 25uF ALCAP electrolytics as output caps and I love the sound of them. Cricklewood electronics in the UK sell them and they ship to the US Here is the cap they are 80 pence each and I'm more than happy with the sound. If you've got any probs sourcing them then I can send you a couple over the pond no probs.

 You may also want to try polypropelyne caps.......... anything greater than 4u7 will do the job.

  Quote:


  Originally Posted by *jnewman* 
_Sorry for all the questions - all my previous electronics work has been sort of works/doesn't work and hasn't been all that affected by small differences in the quality of components._

 

Well let's make sure this one works first time 


  Quote:


  Originally Posted by *jnewman* 
_EDIT: I know I can assemble this stuff just fine, but I'm really curious about how exactly it works. I understand how everything works at an individual component level and how everything fits together with all the amp boards I've looked at, but I'm left with one question - what's the deal with the amplifier stage in the ground channel? Is it to drop the return signal back to line level? Is this necessary because the ground channel isn't a true ground that can completely sump any voltage/current and needs to be fairly balanced with the transmitted signal?_

 

Stay tuned


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_What you pay for when you buy .1% resistors (over and above close tolerance) is a very low temperature coefficency. Standard 1% resistors have a temp. coefficiency of around 500ppm (parts per million) whereas .1% resistors such as the RC55Y's have a low temp. coefficiency of 15ppm. 

 You're not paying for a closer tolerance as 1% resistors can "easily" be matched using a ohmeter. what you are paying for is a lower temperature coefficient resistor which are proven to "sound" better in an audio application...... someone else may wish to elaborate on why low temperature coefficient resistors sound better but I've got to take the dog out......... 
	

	
	
		
		

		
		
	


	




 Basically....... it's not the tolerance that's the key here, it's the low temp. coefficiency._

 

Ahh.... I never would've guessed that, but it makes sense. I see you used them in your WNA headamp, I assume you recommend them?

  Quote:


  Originally Posted by *PinkFloyd* 
_ Quote:


  Originally Posted by *jnewman* 
Sorry for all the questions - all my previous electronics work has been sort of works/doesn't work and hasn't been all that affected by small differences in the quality of components.

 

Well let's make sure this one works first time _

 

Haha... I'll do my best, but I didn't mean none of my electronics stuff has worked all that well, just that I was building things that either did what they were supposed to or didn't - no gradations of quality. Signal purity, frequency response, etc. etc. didn't really matter, so I have no experience selecting components based on trying to create the highest quality output. 
	

	
	
		
		

		
		
	


	




 Thanks for putting up with me!
 Jimmy


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Ahh.... I never would've guessed that, but it makes sense. I see you used them in your WNA headamp, I assume you recommend them?



 Haha... I'll do my best, but I didn't mean none of my electronics stuff has worked all that well, just that I was building things that either did what they were supposed to or didn't - no gradations of quality. Signal purity, frequency response, etc. etc. didn't really matter, so I have no experience selecting components based on trying to create the highest quality output. 
	

	
	
		
		

		
		
	


	




 Thanks for putting up with me!
 Jimmy_

 

The RC55Y resistors are one pound a pop and I would only recommend them to insane people. I used trueohm 0.1% resistors which cost 20p each (slightly less insane!) and are identical to the Welwyns in spec.

 In all the other DIY amps I have built I have implemented 1% metal film resistors (£1 for 100 resistors)

 I, honestly, can't say that 0.1% resistors have brought about any noticeable improvement to the sound, as far as I'm concerned, and anyone who hears an improvement must have ears like a bat.

 As always Jim, it's a matter of choice. If you're on a budget then go for standard 1% resistors........... if you want to spend money and buy low temperature coefficient resistors then go for it....... those little black RC55Y's sure do look pretty


----------



## StevieDvd

OK where to start with first impressions of the White Noise Amp as built for me by Pinkfloyd (Mike)! The bigger box in this thread.

 Got news that the large box had arrived from the North – Bonny Scotland, land of my in-laws. Of course I was still at work and had meetings to attend so only left 6.30pm London GMT and then found trouble with the trains home, of all days it had to be today. Anyway got in at 7.45pm and eagerly opened the box, Mike had certainly gone to town with the packing I think a fresh egg in there would have arrived unscathed. 
	

	
	
		
		

		
		
	


	




 Selected my current 3 favourite CD’s and a mix CD created with some special tracks I like which I used when setting up my hi-fi.

 Kit
 ---
 First source 
 Philips DVD762 (temp till I get a dedicated CD player for the bedroom)

 Second source
 I-Audio M3 with Ogg files at setting 10 (best quality??)

 Headphones 
 Sennheiser HD650’s with Oehlbach cable
 HD600s with the standard 650 cable.
 CDs
 The Gladiator Soundtrack
 Dido – Life for Rent
 Stings Greatest Hits

 Plugged in the amp using a quality home-made interconnect and fired up the source player. Wow. Knee jerk reaction is that someone has put a decent player in the DVD box, everything sounds so much clearer and wider.

 Forgive my improper terminology but to give an idea of the effect ‘before’ and ‘after’; imagine the ‘before’ has the sound in a rectangular box around your head – the sounds are all there and you sort of imagine the spacing between them. Well the 'after' is a bigger box and you can make a better distinction between the individual sounds – guess that’s what some call the soundstage, clearer and wider. Pumped up the volume and no bad effects, distortion or hiss – it’s either music or dead quiet no nasty hum from anything. Any louder would be too loud for me (the wife finds my volume levels far too high) and the volume control is barely a quarter round.

 Now my ears are expecting more I listen and hear extras that were probably there before but not distinct enough to take note of (pun intended).

 Impressions
 ----------- 
 I can hear Dido taking breaths
 That noise is clapping – you can hear the flesh contact not some percussion
 Piano more distinct
 Guitar more twang
 Even heard some sneaky base guitar in a fave track of Dido I’m sure I’ve never noticed that before.

 Yes I’m pleased. Hey, even the wife and daughter said it was ‘clearer’ which from them is high praise. Consider they can’t really detect the difference between my HD650s and the earphones on a cheap mp3 player, I was not expecting them to say anything.

 Parallel test
 -----------
 Well not a fair one but connected the I-audio M3 via line out to the White Noise amp and connected the HD650s. From the headphone socket connect the cheapie cmoy then through to the HD600s.

 The HD600s sounded OK but you switch over to the HD650s and the extra detail and wider sound is definitely there. Switched the headphones around and the WNA still wins.

 Almost had a shock when the wife said she liked the one set better, in the dim light I thought she’d chosen the 600s on the cmoy – but a quick peek at the headband confirmed she’d chosen the WNA config.

 Summary
 ---------
 After listening almost non-stop since I got home with varied music from Eva Cassidy to Techno and Rock classics I’m happy enough. Mike has told me things will burn in and sound better, if so then that’s a plus.

 OK no doubt some will say the source equipment is the problem now but any improvement I make there is pure icing as far as my ears are concerned.


 Well done Mike & WNA!

 Steve :650smile:


----------



## rickcr42

0.1 % resistors are way overkill for audio and unless you are chaining together a serious number of stages in series it makes no sense.

 theoretically you could have a situation where if you use standard off the shelf 1% resistors and do not match them up in stereo pairs you could have all the resistors that are "low" on one channel and all the "high value" resistors in the other channel which would cause a left right imbalance but this is only "theory" and in practice is a non issue.

 But there is a use for precision resistor and that is accuracy in measuring without time/temp variation.

 don't forget-you can only measure something that has low distortion if the measuring device has either LOWER distortion or the distorion value is not only accurate but ALWAYS accurate . A known quantity that the existance of can be predicted and used to null out the measurement

 Not only must this be a predictable number but must be stable for a repeatable result


 hehe ,couldn't resist man


----------



## raja

Hi,

 In my experience the 0.1% resitors do make a very noticable difference. I have compared them to 1% metal films and also tantalum types. The circuit I used was a dual differential cd output stage, each resistor was in series with the signal path. You don't need ears like a bat to hear the diffence either, you get far greater transparancy and low frequency seperation thru the tight tolerance types. The reason for this has also been confirmed by none other than DR. White. What happens is that resistors generally make a noise when passing a signal, this is due to the film vibrating as the signal passes. The cutting process leaves a slight edge on the film that vibrates. Precision resistors are cut to very tight tolerances, and cut very cleanly, this leaves less of the film to make a noise. So really it's a combination of the tolerance and the temprature coefficient that make them better. If you like you can quite easily perform a test. Mike is already in a position to do this, try 1% types in the signal path of the amp, then change back to the 0.1% types. The resistor you are testing should be in series with the signal for the test to work, I don't have the schematics for the amp on hand (can't find 'em), so I can't recommend a postion off hand. Generally you won't hear as big a difference when the resistor is from signal to ground, but in series it's very easy to tell them apart. 
 Mike is right about the pricing of the welwyn's - in comparison to the truohm's they are too expensive, I've ordered some truohm's myself, 20p is a very good price...........


 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_OK where to start with first impressions of the White Noise Amp as built for me by Pinkfloyd (Mike)! The bigger box in this thread.

 Got news that the large box had arrived from the North – Bonny Scotland, land of my in-laws. Of course I was still at work and had meetings to attend so only left 6.30pm London GMT and then found trouble with the trains home, of all days it had to be today. Anyway got in at 7.45pm and eagerly opened the box, Mike had certainly gone to town with the packing I think a fresh egg in there would have arrived unscathed. 
	

	
	
		
		

		
		
	


	




 Selected my current 3 favourite CD’s and a mix CD created with some special tracks I like which I used when setting up my hi-fi.

 Kit
 ---
 First source 
 Philips DVD762 (temp till I get a dedicated CD player for the bedroom)

 Second source
 I-Audio M3 with Ogg files at setting 10 (best quality??)

 Headphones 
 Sennheiser HD650’s with Oehlbach cable
 HD600s with the standard 650 cable.
 CDs
 The Gladiator Soundtrack
 Dido – Life for Rent
 Stings Greatest Hits

 Plugged in the amp using a quality home-made interconnect and fired up the source player. Wow. Knee jerk reaction is that someone has put a decent player in the DVD box, everything sounds so much clearer and wider.

 Forgive my improper terminology but to give an idea of the effect ‘before’ and ‘after’; imagine the ‘before’ has the sound in a rectangular box around your head – the sounds are all there and you sort of imagine the spacing between them. Well the 'after' is a bigger box and you can make a better distinction between the individual sounds – guess that’s what some call the soundstage, clearer and wider. Pumped up the volume and no bad effects, distortion or hiss – it’s either music or dead quiet no nasty hum from anything. Any louder would be too loud for me (the wife finds my volume levels far too high) and the volume control is barely a quarter round.

 Now my ears are expecting more I listen and hear extras that were probably there before but not distinct enough to take note of (pun intended).

 Impressions
 ----------- 
 I can hear Dido taking breaths
 That noise is clapping – you can hear the flesh contact not some percussion
 Piano more distinct
 Guitar more twang
 Even heard some sneaky base guitar in a fave track of Dido I’m sure I’ve never noticed that before.

 Yes I’m pleased. Hey, even the wife and daughter said it was ‘clearer’ which from them is high praise. Consider they can’t really detect the difference between my HD650s and the earphones on a cheap mp3 player, I was not expecting them to say anything.

 Parallel test
 -----------
 Well not a fair one but connected the I-audio M3 via line out to the White Noise amp and connected the HD650s. From the headphone socket connect the cheapie cmoy then through to the HD600s.

 The HD600s sounded OK but you switch over to the HD650s and the extra detail and wider sound is definitely there. Switched the headphones around and the WNA still wins.

 Almost had a shock when the wife said she liked the one set better, in the dim light I thought she’d chosen the 600s on the cmoy – but a quick peek at the headband confirmed she’d chosen the WNA config.

 Summary
 ---------
 After listening almost non-stop since I got home with varied music from Eva Cassidy to Techno and Rock classics I’m happy enough. Mike has told me things will burn in and sound better, if so then that’s a plus.

 OK no doubt some will say the source equipment is the problem now but any improvement I make there is pure icing as far as my ears are concerned.


 Well done Mike & WNA!

 Steve :650smile:_

 

Hi Steve,

 Great to hear your initial impressions even though, from my calculations, you've only listened to the amp for a few hours....... seriously, give it a couple of days to bed in and when you've got the time have a really good long listen 

 I'm not really up on Dido but if you can hear her taking breaths then that's good 
	

	
	
		
		

		
		
	


	




 It's always a good sign when non audiophile members of the family say things like "it sounds very clear" as opposed to "it sounds just the same as the other one to me" 
	

	
	
		
		

		
		
	


	




 What position on the volume knob do you listen at with 7am being minimum and 5pm being maximum? A quarter of the way around would be between the 9am and 10am position (if looking at the knob as a clock face) If it's "loud" between the 9am and 10am position then I can reduce the gain..... it should be pretty comfortable at the 9 - 10am position and should only become loud around the 12pm -1pm mark...... well that's how it was with my source...... there's no problem reducing the gain it's a simple case of replacing 2 resistors.

 If you've got a tuner then you can hook the amp and phones up to it and leave it playing for 48 hours.... it should sound a lot more open and beefier after a good old burn in.

 Anyways, if you find the amp too loud at a lowish volume setting then I can reduce the gain no problems 

 All the best.

 Mike.


----------



## rickcr42

Quote:


 In my experience the 0.1% resitors do make a very noticable difference. I have compared them to 1% metal films and also tantalum types. 
 

so you are telling me that you put 0.1% resistor into something and it will sound better than me using matched sets of 1% resistors ?

 that is not my experience at all and i have been doing audio since 1972.

 but hey ,different strokes man.You are more than welcome to use whatever.
 Diy should be labelled "UWYW" for Use What You Want

 I just hate to see misinfoirmation thrown around where there are impressionable newbies who have to have the latest and the greatest of everything thinking they can get the ultimate by listening to other people instead of their own gear.


----------



## rickcr42

hey pink ,did you really have to copy the entire post man ?

 better to cut just the highlights and respond to each as needed and make it easier on the rest of us dude.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Steve,

 Great to hear your initial impressions even though, from my calculations, you've only listened to the amp for a few hours....... seriously, give it a couple of days to bed in and when you've got the time have a really good long listen _

 

I was still listening at 2am this morning.

  Quote:


 I'm not really up on Dido but if you can hear her taking breaths then that's good 
	

	
	
		
		

		
		
	


	




 It's always a good sign when non audiophile members of the family say things like "it sounds very clear" as opposed to "it sounds just the same as the other one to me" 
	

	
	
		
		

		
		
	


	



 . 
 

Hey don't knock the non audiophiles, I used the fact that they could not detect a difference in headphones as an excuse to get the amp. 
	

	
	
		
		

		
		
	


	



  Quote:


 
 What position on the volume knob do you listen at with 7am being minimum and 5pm being maximum? A quarter of the way around would be between the 9am and 10am position (if looking at the knob as a clock face) If it's "loud" between the 9am and 10am position then I can reduce the gain..... it should be pretty comfortable at the 9 - 10am position and should only become loud around the 12pm -1pm mark...... well that's how it was with my source...... there's no problem reducing the gain it's a simple case of replacing 2 resistors. 
 

No problem I omitted to mention the mp3 lineout source was much quieter as was the micro hi-fi downstairs which also got to link up with the WNA. 

  Quote:


 If you've got a tuner then you can hook the amp and phones up to it and leave it playing for 48 hours.... it should sound a lot more open and beefier after a good old burn in.
 . 
 

There's more chance of invaders from Mars than the missus accepting something left on like that - she'd unplug the freezer if she could. Standby power is a nono in our house (I've learned to live with that for an easier life) but I can always try. Would I need to have any headphones plugged in as well? Though I expect to run it in a bit more with me included in the connection somehow at first. I'm looking for a killer track to use as a comparison - I did hear some bits I thought would be good examples but I was enjoying the music, so the analytical part took a back seat last night.


 Steve


----------



## raja

Quote:


  Originally Posted by *rickcr42* 
_so you are telling me that you put 0.1% resistor into something and it will sound better than me using matched sets of 1% resistors ?

 that is not my experience at all and i have been doing audio since 1972.

 but hey ,different strokes man.You are more than welcome to use whatever.
 Diy should be labelled "UWYW" for Use What You Want

 I just hate to see misinfoirmation thrown around where there are impressionable newbies who have to have the latest and the greatest of everything thinking they can get the ultimate by listening to other people instead of their own gear._

 




 I'm using the statement you posted above with the info I posted below it to justify my findings, if you find different fair enough. But I have no need to lie, I'm sure you don't either. I have always tried to take a neutral view whilst posting on this thread, and have never tried to push anything onto anyone. I invite people to make thier own tests, and if they confirm my findings and find pleasure in it , very well. I don't make money on anything, least of all resistors. Like I said it's easy for them, to pick one resistor out of the signal path and find out for themselves. My explanation, which is actually David White's explanation did not offer blind info of just tolerance, bottom line is that tolerance lazer cutting reduces noise from the film of the resistor. Your findings may well be different, where as I have no paper qualifications, David White is a qualified EE, and certainly uses logic to determine fact from myth.
 If I have come accross as some kind of know it all or audio Guru then I apologise. 


 Thanks
 Raja


----------



## rickcr42

nononon man !

 you misunderstand my point or it came across other than intended !

 I just have to put a counter out to such a definitive statement as :

  Quote:


 In my experience the 0.1% resitors do make a very noticable difference. 
 

would be taken as gospel by some here with very little experience .They trust those who have actually assembled gear to guide them and if that staement were just left as is without any counter the asssumption would be that it was something everyone agrees on.

 i just happen to not agree .

 No way anyone convinces me that the tolerance of a part has more bearing on the sound than does the material or means of constructiom.Passive parts and power supplies have way more bearing on the final sound than does the active device being used.

 We can both use identical active stages and build from the identical schematic and in the end have two entirely different sounding amps according to our parts selection.

 tolerance means nothing ,nada,except in relation to interchannel balance or if a frequency dependant circuit the time/freq/balance relationships.and even here 1% is sufficient in 99.9% of the cases and with caps 5-10% unless it is a RIAA eq or other precision network

 And again even here it is better to have frequency differences with a good sounding part than to be precise but use a part with questionable sonics


----------



## jnewman

See, I have two schools of thought:

 1. This is my first piece of audio equipment (done other electronics) so I should just buy decent components and put it together.

 2. This is my first piece of audio equipment (done other electronics) so I should buy top-quality parts so I'll have a top-quality amp that I'm less inclined to continually buy new bits to upgrade with (and maybe even hold off on moving on to a newer amp for a bit more time 
	

	
	
		
		

		
		
	


	




 ).

 We'll see what ends up happening, but I suspect that my growing chronic upgradeitis will take effect before I have anything to upgrade. Oh, and rickcr43 - I won't have enough resistors to be able to match them to a higher tolerance, I'm ordering exact quantities specifically for this project. I'm NOT necessarily saying this justifies .1% resistors, just that I won't have the option of matching 1% resistors to .1%.

 Jimmy.


----------



## PinkFloyd

Quote:


  Originally Posted by *rickcr42* 
_did you really have to copy the entire post man ?
_

 

My apologies Rick.

 I still haven't quite grasped the fine art of the quote but I'm working on it 

 Best.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_
 Hey don't knock the non audiophiles, I used the fact that they could not detect a difference in headphones as an excuse to get the amp. 
	

	
	
		
		

		
			





_

 

Hi Steve,

 What I meant by that was that people who are not really into Hi-Fi in a big way generally say "it all sounds the same to me" when confronted by an audio enthusiast demonstrating their latest and greatest to them. When they say "that sounds a lot clearer" you know you're onto a winner as they can actually hear a difference 

 I still don't know if that makes sense 
	

	
	
		
		

		
		
	


	




 enjoy the music Steve 
	

	
	
		
		

		
		
	


	




 Regards.

 Mike.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_What I meant by that was that people who are not really into Hi-Fi in a big way generally say "it all sounds the same to me" when confronted by an audio enthusiast demonstrating their latest and greatest to them. When they say "that sounds a lot clearer" you know you're onto a winner as they can actually hear a difference _

 

I agree. Was being cheeky in implying I needed an excuse (as if)!

  Quote:


 I still don't know if that makes sense 
	

	
	
		
		

		
		
	


	



 

Makes the sense as it was what I was trying to say as well. 
	

	
	
		
		

		
		
	


	




 Am I now Team WNA?

 Steve


----------



## raja

Quote:


  Originally Posted by *rickcr42* 
_nononon man !

 you misunderstand my point or it came across other than intended !

 I just have to put a counter out to such a definitive statement as :



 would be taken as gospel by some here with very little experience .They trust those who have actually assembled gear to guide them and if that staement were just left as is without any counter the asssumption would be that it was something everyone agrees on.

 i just happen to not agree .

 No way anyone convinces me that the tolerance of a part has more bearing on the sound than does the material or means of constructiom.Passive parts and power supplies have way more bearing on the final sound than does the active device being used.

 We can both use identical active stages and build from the identical schematic and in the end have two entirely different sounding amps according to our parts selection.

 tolerance means nothing ,nada,except in relation to interchannel balance or if a frequency dependant circuit the time/freq/balance relationships.and even here 1% is sufficient in 99.9% of the cases and with caps 5-10% unless it is a RIAA eq or other precision network

 And again even here it is better to have frequency differences with a good sounding part than to be precise but use a part with questionable sonics_

 




 Dude,

 Fact is we are both talking of the same point, I had to refer to the tolerance as that was the initial topic, although i used it to explain my own findings incorrectly

 in the case of the resistors mentioned it's the level of noise they make that makes the difference. In this context moderator I agree with you, my initial statement was misleading. Tolerance does not determine the ability of a resistor to influence sound, however, the noise a resistor makes whilst passing a signal does have an influence on the sound.

 So yes dude you were correct, and I should have worded my initial response in line with the technical performance of the resistors rather than the tolerance..........
 My apologies

 Thanks
 Raja


----------



## raja

In any case back to circuit talk. I was wondering if one could use this amp with a power follower circuit such as some of the single ended followers I have seen on the web (Ciuffolli has one on his site). I'm guessing if one were to increase the gain of the amp, and connect the follower after it, this would make quite a mean bedroom amp?

 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_
 Mike is already in a position to do this, try 1% types in the signal path of the amp, then change back to the 0.1% types. The resistor you are testing should be in series with the signal for the test to work, I don't have the schematics for the amp on hand (can't find 'em), so I can't recommend a postion off hand. Generally you won't hear as big a difference when the resistor is from signal to ground, but in series it's very easy to tell them apart. 
_

 

Hi Raja,

 I very much doubt if I could remember exactly what the amp sounded like with 1% resistors in the signal path by the time I'd swapped them over to .1% variants (desoldering / soldering refitting the board etc.) 

 To be absolutely certain, and prove beyond doubt, that the .1% resistors improved the sound quality I would have to build 2 identical amps, one with 1% resistors and the other with .1% resistors. Obviously all of the other components in both of the amps would have to be matched to within zero tolerance to make the comparitive test somewhat foolproof.... this would also include ensuring each solder joint was filled with the same amount of solder in both amps, lengths of hook up wire were the same and so on and so forth.

 It would take a lot of time and some seriously expensive equipment to build 2 amps (minus the resistors) that were "100%" identical in every respect.

 Then it would be a case of devising a foolproof way of (I can't mention the D*test word as this is a D*test free forum) comparing the two amps and ascertaining which one sounded better ..... amp A with the .1% resistors or amp B with the 1% resistors.......

 I had the good fortune to have 2 WNA amps side by side when I was evaluating the AD8610 / LM6171 op amps and to my ears the LM6171 sounded best. At head-fi, though, that's not considered as a foolproof test as a lot of variables can enter the equation.

 Anyways, I don't want to go down that road and there are lots of discussions regarding .1% V 1% resistors that can be found in the head-fi archives. It's not a big issue, IMO, and the placebo effect can play a huge part in your perception of the role resistors play in a circuit. Everybody likes to think they've fitted the best part for the job and if little black RC55's costing a quid each go toward improving the sound, in the eye of the constructors subconscience, then it's served its purpose and is well worth the money as far as that individuals musical enjoyment is concerned.

 I'm with Rick on this one and the only reason I've adopted the true ohm .1% resistors into my WNA is the fact they are 20p each and you can buy them in multiples of "one" so they work out cheaper than buying 100 x 1% resistors at 70p for 100...... ie: 2 x 300 ohm .1% resistors would cost me 40 pence. 100 x 300 ohm 1% resistors would cost 70 pence........ sure I get 98 more resistors for 30 pence more but will I ever use them? 

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_In any case back to circuit talk. I was wondering if one could use this amp with a power follower circuit such as some of the single ended followers I have seen on the web (Ciuffolli has one on his site). I'm guessing if one were to increase the gain of the amp, and connect the follower after it, this would make quite a mean bedroom amp?

 Thanks
 Raja_

 

Hi Raja,

 before even attemping an answer I gotta know what a "bedroom amp" is? 
	

	
	
		
		

		
		
	


	




 Am I missing something here? Please don't tell me a bedroom amp incorporates an independent supply for an adult toy


----------



## rickcr42

well guys ,all i can say is tolerance be damned but the only time i here a difference is between carbon/carbon film/thin film metal film/thick film metal /tantalum/inductive/non inductive and any can be matched to any decimal poit if the accuracy of the measuring device is up to it.

 precision parts only give you predictable results but more often than not designing something and then building it you round up or down to the nearest standard part for the build and this already blows the 0.1 % deal to hell !

 you want REAL accuracy ?

 Measure the suckers with a null bridge and then use a file the one with the higher value until the resistors "null out"

 this is the closest to "exact" you can get


----------



## PinkFloyd

Quote:


  Originally Posted by *rickcr42* 
_well guys ,all i can say is tolerance be damned but the only time i here a difference is between carbon/carbon film/thin film metal film/thick film metal /tantalum/inductive/non inductive and any can be matched to any decimal poit if the accuracy of the measuring device is up to it.

 precision parts only give you predictable results but more often than not designing something and then building it you round up or down to the nearest standard part for the build and this already blows the 0.1 % deal to hell !

 you want REAL accuracy ?

 Measure the suckers with a null bridge and then use a file the one with the higher value until the resistors "null out"

 this is the closest to "exact" you can get_

 

That's the best you can hope to acheive....... agreed


----------



## The_Mac

Quote:


  Originally Posted by *rickcr42* 
_well guys ,all i can say is tolerance be damned but the only time i here a difference is between carbon/carbon film/thin film metal film/thick film metal /tantalum/inductive/non inductive and any can be matched to any decimal poit if the accuracy of the measuring device is up to it.

 precision parts only give you predictable results but more often than not designing something and then building it you round up or down to the nearest standard part for the build and this already blows the 0.1 % deal to hell !

 you want REAL accuracy ?

 Measure the suckers with a null bridge and then use a file the one with the higher value until the resistors "null out"

 this is the closest to "exact" you can get_

 


 I think the point RAJA was making is that the accuracy of the matching isn't what gives the sonic benefit of using 0.1% over 1%, it's the manufacturing process and the physical aspects of the part, not the tolerances. His contention is that because of the more precise way that the part is machined, there's less of a burr, or less of a shear distortion on the machined edge and that is what gives the advantage. He is saying that the larger edge burrs or edge imperfections in the standard parts negatively influences the sound.

 This seems to fit with your own philosophy that there will be little sonic difference between poorly matched and precisely matched parts of the same type, but that there will be larger sonic differences between different physical types of parts. This is a different manufacturing process which yields a physically different part, as opposed to identical parts that have been matched more precisely.


----------



## rickcr42

Quote:


 He is saying that the larger edge burrs or edge imperfections in the standard parts negatively influences the sound. 
 

in a low gain circuit such differences would be inaudible , at least to me , and even if not ,unless your entire signal path from front end to final transducer also maintianed the same fanatical levels of parts selection any perceived benefit would be imaginary at best.
 One inline cap would impart more of a sonic signature than a resistor or even a group of resistors and noise is also a .

 non issue if the values of the resistor are kept low

 you can not get rid of the noise inherent in the circuit but you could add to that noise if you use large value resitors,no matter what the method of construction.


 but again ,whatever floats your boat guys


----------



## jnewman

Well, whether it actually helps or just imparts a psychosomatic effect, I'll probably get suckered into using them. On a related note, I'm also going to see about obtaining a bit of rainbow foil to stick in the box 
	

	
	
		
		

		
		
	


	




.

 Edit: Just so noone gets the wrong idea, the only one convincing me to buy expensive components is me.


----------



## rickcr42

I only jumped in because far too many are busy pouring through catalogs and then when they spend long green on a "super part" they ethen post here and tout this part as the be all end all to audio bliss.

 Then the "leemmings" all fall into lock step and follow down the same path without ever listening to a single part in a circuit they are familiar with the sound of , then they tell anyone willing to listen how it is the best thing since sliced bread !

 My point of view through many years of mucking aroiund and blowing up more than my share of "stuff' is that you can take two parts that look good as individual pieces and then put them together and end up with horiffic sound !

 these same parts may play well together with others but in the same room they are poison and must be separated.

 If you consider all parts of a design like you would when you match a speaker system to a power amp you will realise that a GREAT amp and a WRLD CLASS speaker system sometimes just do not match up sonically.

 either peice may be great elswhere but together -no.

 You take a bunch of parts ,throw them into something and just because someone told you they are the best do not expect results better than some joker throwing together off the shelf parts and getting lucky.

 Comes down to matching the sonics of each part for the intended position in the device being assembled and one brand of capacitor or one style and brand of resistor is not always a good idea at best and a bad idea at worst.

 A bias resistor does not perform the same function as a coupling resitor or a filter network element so why would you just assume the same part will perform equally well in any situation ?

 would you use a dump truck to drive to the mail box ?

 A Drag Racer to go get a quart of milk ?

 Bring a compact car to home depot and then try to load 25 sheets of sheetrock on top ? (OK ,maybe the last one)

 All the examples above are things out of place but each has a place where it rules , i.e a drag strip for the drag racer, compact car banging around town and the truck at the depot 

 soit kinda tightens my undies up a bit when the easily persuaded jump on the bandwagon when they have no clue where that wagon is going.

 I ove it when someone buys a DVD player , modifies it right out of the box and then has the nerve to go online and tell everyone how much better it sounds.

 How the hell would that person know ?

 compared to what ?

 Obviously not the stock machine.

 without a benchmark to compare against no one has a clue if something sounds "better" or not and anyone that does more than one upgrade at a time can not honestly say which one made the most difference-they do not know !

 Not trying to jump anyone or burst any bubbles but misinformation and "opinions" need someone to be the foil,to come at some things with a counter and I guess that is my place.
 I am a skeptic by nature and until i hear- see- touch a thing it does not exist and no way in my experience does a 0.1% precision resistor have any bearing on the superiority of an op-amp based headphone amp sound quality

 just my opinion,don't mean nothing


 rick the spoiler


----------



## jnewman

Quote:


  Originally Posted by *rickcr42* 
_rick the spoiler 
	

	
	
		
		

		
		
	


	


_

 

You're not spoiling anything 
	

	
	
		
		

		
		
	


	




.

  Quote:


  Originally Posted by *rickcr42* 
_I only jumped in because far too many are busy pouring through catalogs and then when they spend long green on a "super part" they ethen post here and tout this part as the be all end all to audio bliss.
 ...
 If you consider all parts of a design like you would when you match a speaker system to a power amp you will realise that a GREAT amp and a WRLD CLASS speaker system sometimes just do not match up sonically.

 either peice may be great elswhere but together -no._

 

I do know EXACTLY what you're talking about. I have essentially no experience with DIY headphone amplification, and not what I would call a lot with headphone amps themselves, but I've spent a pretty good amount of time with power amps and speakers and preamps and turntables and so on and so forth and so on some more, and what you're saying is something I'm very familiar with.

  Quote:


  Originally Posted by *rickcr42* 
_Comes down to matching the sonics of each part for the intended position in the device being assembled and one brand of capacitor or one style and brand of resistor is not always a good idea at best and a bad idea at worst.

 A bias resistor does not perform the same function as a coupling resitor or a filter network element so why would you just assume the same part will perform equally well in any situation ?_

 

You've got me, I admit to not having a clue as to what kind of resistors sound the best in the given sections of a power amplifier - but I'm told generally to use all metal films, and I assume that better tolerances and less change due to temperature and less noise and so on can't hurt.

  Quote:


  Originally Posted by *rickcr42* 
_Bring a compact car to home depot and then try to load 25 sheets of sheetrock on top ? (OK ,maybe the last one)_

 

Everyone's done that at least once, whether it's sheetrock or some matresses or a big table or something else 
	

	
	
		
		

		
		
	


	




.

  Quote:


  Originally Posted by *rickcr42* 
_soit kinda tightens my undies up a bit when the easily persuaded jump on the bandwagon when they have no clue where that wagon is going.

 I ove it when someone buys a DVD player , modifies it right out of the box and then has the nerve to go online and tell everyone how much better it sounds.

 How the hell would that person know ?

 compared to what ?

 Obviously not the stock machine.

 without a benchmark to compare against no one has a clue if something sounds "better" or not and anyone that does more than one upgrade at a time can not honestly say which one made the most difference-they do not know !_

 

Not knowing enough to guess specifically what will work the best in each position in this amp, I admit that I'll be jumping on a few bandwagons without knowing where I'm going - but I'm sure I'll change things out at some point and learn a bit about how things change, and I can afford to buy a few expensive parts, at least for my first project.

 And believe me, I won't go saying "OH man this amp sounds good, those .1% resistors sound SO much better than 1%s" (assuming, of course, that I actually end up using .1%s, that the amp works, and that it actually DOES sound good 
	

	
	
		
		

		
		
	


	




 ) - I'll just talk about how it sounds, period, in itself, to me, and maybe (if it really does sound good) that I'm proud of it and that I'm glad I went ahead and bought the expensive parts because all together it just plain sounds good and I know it's a quality amp. Or maybe I'll say "my $70 mint amp that I bought sounds better than this piece of crap, why on earth did I spend twenty bucks on resistors?" I'll either get a good amp or I'll learn something about how all the parts I bought fit together, and not put them all together in another project in the future.

  Quote:


  Originally Posted by *rickcr42* 
_Not trying to jump anyone or burst any bubbles but misinformation and "opinions" need someone to be the foil,to come at some things with a counter and I guess that is my place.
 I am a skeptic by nature and until i hear- see- touch a thing it does not exist and no way in my experience does a 0.1% precision resistor have any bearing on the superiority of an op-amp based headphone amp sound quality

 just my opinion,don't mean nothing_

 

You're not jumping anyone or bursting any bubbles, and I wasn't looking at .1's as some magical gate into perfect sound, I just don't know a lot about this and am looking to get as much advice as I can about this whole business, which is exactly why your opinions DO mean something - you know a lot more about this than I do.

 That being said, I'm probably going to spend more on this than I should because it's my first amp and I really want to do it right and make sure I build the best amp I can, one I'll really be happy with and will feel I've built well. (I'm really picky and don't want to feel like I haven't done the very best job I can, particularly on this project).

 After all that writing, I also want to thank everyone who's been posting here recently to me (or about me 
	

	
	
		
		

		
		
	


	




 ) for giving me so much of their time and trying to steer me in the right direction without getting grumpy or condescending (i.e. everyone).

 Thank you,
 Jimmy.


----------



## raja

Hi,

 at least one person understood what I was trying very hard to write. The manufacturing process does influence the sound. 

 A very simple test without the need for desoldering the entire pcb etc would be to solder a resistor inline with the rca input to the amp, if you have a switch then you could easily solder the normal metal films to one of the other inputs and quickly switch back, to see if there is a difference.

 Dan Banquer made an amp for a customer using bulk foil types over metal films, and because of their lower noise, the whole signal to noise ratio was reduced by 10db, go figure for yourself........

 How does this relate to this? Well the process used whilst making the types of resistor mentioned are superior to the normal metal films period. You can read the data sheets for yourself, and where normally specs don't ensure good sound, the noise level of a component does influence it.

 Hey if you can find a metal film that has the same noise level as the welwyn's or truohms then let me know, I'll use them instead if it's cheaper!


 All I was trying to point out was that when the resistor is INLINE with the signal path you can hear the difference very clearly. I tested the welwyns against the maplin generic metal films, and found the differnce to be quite substantial. No subconscience stuff.


 I tried to point out before that it's not the overall tolerance thats the influence, but the techniques used in the process of manufacture, so please let go of the tolerance issue. I appologised for my error of description before and I do it again.

 With regards to bedroom amp, I meant a low power amp capable of delivering good sonics. No inuendo intended........

 It's all very good being sceptical, but if you won't believe anyone, then at least test their theory for yourself, before making a final judgement based on your logic alone. I have nothing to gain and was only trying to share my experience. 
 I do think the sceptic nature of each person is healthy in audio, but how can someone put any info forward, if we are not prepared to test what they say, and instead tell them they are imagining a difference?

 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *rickcr42* 
_would you use a dump truck to drive to the mail box ?

 A Drag Racer to go get a quart of milk ?

 Bring a compact car to home depot and then try to load 25 sheets of sheetrock on top ?_

 

You crack me up man


----------



## Alick

Well, it's finished and it worked first time. It's a while since I've built anything - I must say I really enjoyed the experience. I've just had a quick listen and it sounds really promising - loads of detail and very musical with it. I swear I heard Butch Hancocks finger-nail strike the sound-board of his guitar on one track, which I've never noticed before. Anyway, I've just taken a quick break from building a fence to have a coffee, a quick listen and to post some hastily taken snaps. As you can see, I'm neither a photographer nor a wire-man (unlike Mike) and the wiring is a bit of a lash-up as I was keen to get listening this weekend. I'll probably re-wire and use some heat-shrink sleeving of the terminations at some later point but for now I just want to enjoy the music.

 As we speak, I'm racking up 10 hours burn-in before a serious listening session tonight. BTW Mike, the 20k Alps pot gives me a really satisfactory range of control with the standard design gain so I'll leave it where it is. Thanks for all the bits and pieces and for the encouragement. I'll post more views after more listening.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_





 Well, it's finished and it worked first time. It's a while since I've built anything - I must say I really enjoyed the experience. I've just had a quick listen and it sounds really promising - loads of detail and very musical with it. I swear I heard Butch Hancocks finger-nail strike the sound-board of his guitar on one track, which I've never noticed before. Anyway, I've just taken a quick break from building a fence to have a coffee, a quick listen and to post some hastily taken snaps. As you can see, I'm neither a photographer nor a wire-man (unlike Mike) and the wiring is a bit of a lash-up as I was keen to get listening this weekend. I'll probably re-wire and use some heat-shrink sleeving of the terminations at some later point but for now I just want to enjoy the music.

 As we speak, I'm racking up 10 hours burn-in before a serious listening session tonight. BTW Mike, the 20k Alps pot gives me a really satisfactory range of control with the standard design gain so I'll leave it where it is. Thanks for all the bits and pieces and for the encouragement. I'll post more views after more listening._

 

That's a great job you've made of the amp Alick.... very tidy indeed. If you send me a few full size pics I'll upload them to the web so we can see the pRon in greater detail 
	

	
	
		
		

		
		
	


	




 Glad you like the sound and it's comforting to know I'm not imagining hearing subtle details I haven't heard with other amps. Hearing Butch Hancock's finger-nail striking the sound-board of his guitar sure sounds good to me 

 BTW what value of resistor did you use for the LED?

 All the best.

 Mike.





 Alick's amp





 Alick's amp 2


----------



## Alick

Mike

 I've sent pictures - thanks. I used a 2k with the LED - works out at 12mA. I presume you're getting these showers down in the East Neuk? It's giving me too many excuses to abandon fence-building and dive indoors for a sneaky listen.
	

	
	
		
		

		
		
	


	




.


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## PinkFloyd

Well that's me finally bolted the lid down as I'm absolutely over the moon with the sound quality and I'm frightened I may over egg the pudding if I start messing about with things. That's the lid bolted down for good on this one now it's time to listen to the music


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Mike

 I've sent pictures - thanks. I used a 2k with the LED - works out at 12mA. I presume you're getting these showers down in the East Neuk? It's giving me too many excuses to abandon fence-building and dive indoors for a sneaky listen.
	

	
	
		
		

		
		
	


	




._

 

No rain here Alick, quite pleasant in fact. I'm on 56kps dial up and your 6mb of pics are taking a while to download but I'll optimise them for the web as soon as they download  my word one of the pics is 3mb!!!!! wow


----------



## Alick

Here are the images of my WNA, courtesy of PinkFloyd.
















 Thanks Mike!


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Here are the images of my WNA, courtesy of PinkFloyd.
















 Thanks Mike!_

 


 Nice, very nice indeed Alick! I think I may go back to the red LED it looks pretty cool in the recessed chrome bezel. 

 Great job 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## Alick

Thanks. I've just noticed that it looks like the amp is powered in the picture - it isn't. That's just the sun (between the showers) reflecting on the LED.

 EDIT: Mmmmm - looks like there's room for a crossfeed in the back of the case there...


----------



## PinkFloyd

For all you guys debating the pro's and con's of .1% V 1% resistors Dr. White's stance is as follows:

 [size=medium]  "Can I give you my take on the precision resistors. When you pass a varying current through a resistor it will heat up and cool down in time lagged sympathy with the signal. This will cause the resistance value to be modulated which in turn will introduce distortion if the resistor is in the signal path. This effect is very small unless the current is substantial, as is the case with low value feedback resistors in power amps, or the resistor has a very high temperature coefficient of resistance. With 0.1% resistors the precision doesn't matter a damn in most ( audio ) circumstances, but what does matter is that the temperature coefficient of the commonly available types is 15ppm compared with 50ppm for a bog standard metal film resistor. So the ( very small ) distortion effects produced by modulation of the resistance is much smaller with these 0.1% resistors than with 1% metal films. Bulk foils typically have temperature coefficients of around 2ppm. Another factor which can also have an effect is the metal used to construct the end caps and connecting wires of the resistor. Ferrous metals introduce non-linearities and unfortunately all of the commonly available metal film resistors, whether they be 1% or 0.1%, have steel end caps, although the leadout wires are copper in most instances. The reason why the old "dog and bone" style Holcos were so prized is that they had copper end caps. The construction of resistors, in the broadest sense, ( and their value, of course ) does affect their noise contribution, but with headphone amplifiers the signal levels are sufficiently high that this is not really a consideration. But if you were designing a moving coil phono amp the noise situation would be entirely different. All of the foregoing effects are measurable, but as to whether they're audible.............? "   [/size]

 The part where Dr. White says "with headphone amplifiers the signal levels are sufficiently high that this is not really a consideration" suggests to me that .1% resistors will make no improvement to the sound, whatsoever, in this "specific" headphone amp application and 1% resistors will give the same audible results. Similarly, .1% resistors will do no harm and I can understand why people implement them in headphone amps believing they will make the sound "better". Now the explanation has been given it'll save head-fiers a lot of money on resistors  

 On a side note, I'd like to thank Dr. White for his honest and very professional / extremely informative responses to my queries throughout this topic and I, for one, have learnt a lot from his superb explanations and opinions. This topic started out as another "look at what I've made" posting but has turned into one of the most interesting and informative topics of discussion I have ever come across on head-fi thanks to Dr. White's input.

 Mike.


----------



## jnewman

Or MAYBE what he's saying is that since it doesn't make much of a difference you need to spend really a lot of money and buy bulk foil resistors because they're even better... 
	

	
	
		
		

		
		
	


	




 Just kiddin' - at six to ten bucks a pop, that'd get real expensive real fast, and I do understand that he's saying there's no real sonic difference at all in this type of application.


----------



## guzzler

I can't see the justification for the mega expensive film caps, but for the TruOhms for example, it's not so much that you're paying for a nice resistor, it's the fact you don't need to buy 100 of them to get *1* nice resistor. The things you get from Maplin in singles have leads about the width of a hair and they often give you the wrong ones as well. The TruOhm .1% resistor is a quality piece, that looks and feels better constucted and I'm happy to pay that little extra for such a demanding application

 g


----------



## jnewman

Quote:


  Originally Posted by *guzzler* 
_I can't see the justification for the mega expensive film caps, but for the TruOhms for example, it's not so much that you're paying for a nice resistor, it's the fact you don't need to buy 100 of them to get *1* nice resistor. The things you get from Maplin in singles have leads about the width of a hair and they often give you the wrong ones as well. The TruOhm .1% resistor is a quality piece, that looks and feels better constucted and I'm happy to pay that little extra for such a demanding application

 g_

 

I was teasing about the foil caps... I AM probably going to get the .1%'s though. I've been searching around and I can't find anywhere that sells (or even references) TruOhm resistors, though - where can I find them?

 Jimmy.


----------



## PinkFloyd

Quote:


  Originally Posted by *guzzler* 
_I can't see the justification for the mega expensive film caps, but for the TruOhms for example, it's not so much that you're paying for a nice resistor, it's the fact you don't need to buy 100 of them to get *1* nice resistor. The things you get from Maplin in singles have leads about the width of a hair and they often give you the wrong ones as well. The TruOhm .1% resistor is a quality piece, that looks and feels better constucted and I'm happy to pay that little extra for such a demanding application

 g_

 

exactly. As I pointed out earlier in the thread 2x 100R 0.1% truohms cost 40 pence. 100 (one hundred) x 100R 1% costs 70 pence. I only require 2 of each in the amp so it would cost me more to buy 100 x 1% resistors in this application. There's no sonic gain to be had with the 0.1% resistors but they are sold in multiples of 1 so work out cheaper than buying a batch of 100 resistors at .7p each (70p) 

 I'm not buying .1% resistors because they're better........... I'm buying because they are affordable and can be bought in multiples of one as opposed to one hundred.


----------



## rickcr42

Quote:


 It's all very good being sceptical, but if you won't believe anyone, then at least test their theory for yourself, before making a final judgement based on your logic alone. I have nothing to gain and was only trying to share my experience. 
 



 i am not talking about any "theory" but actual bench time building well over a thousand headphone amplifiers !

 I have been designing and assembling my own audio equipment for thirty some odd years and i think that qualifies as "experience".

 The insinuation that i am talking just to do it is way off base man.

 i do not have to "revisit" old news to verify what i already know to be true

 rickmonster


----------



## PinkFloyd

Quote:


  Originally Posted by *rickcr42* 
_i am not talking about any "theory" but actual bench time building well over a thousand headphone amplifiers !

 I have been designing and assembling my own audio equipment for thirty some odd years and i think that qualifies as "experience".

 The insinuation that i am talking just to do it is way off base man.

 i do not have to "revisit" old news to verify what i already know to be true

 rickmonster_

 

Rick, 

 I respect you as both a moderator and a friend. This thread is about the WNA kit amplifier........... can we keep to the point?

 Thanks.

 Mike.


----------



## rickcr42

have at it but i will not have people question my credentials.

 They can disagree ,that is what audio is all about,but the the comments tossed in are entirely uncalled for and i do not need to be told to "compare".

 My DIY history is there for anyone interested enough to look.
 Very well documented and extensive


----------



## PinkFloyd

come on Rick don't be daft, I doubt anyone knowingly doubted / questioned your credentials............ you're well respected here, Im your biggest fan, cut Raja some slack Rick.... he's a new member and he's not aware of how sharp your teeth are 
	

	
	
		
		

		
			






 Mike.


----------



## rickcr42

talk about the amp at will but when I am questioned i will still respond.to do anything else would be "daft"


----------



## jnewman

I thought I'd posted this an hour ago and just realized I didn't, so here it is:

 Rick - I do appreciate both your experience and your advice regarding the amp and general DIY audio - please see my post about ten posts back (why do the positive ones always get missed?). Everyone's a bit touchy in here, but you've said some really helpful things.

 Jimmy.


----------



## PinkFloyd

Quote:


  Originally Posted by *rickcr42* 
_talk about the amp at will but when I am questioned i will still respond.to do anything else would be "daft"_

 


 Sure but I wouldn't (personally) let a .1% resistor get me that heated up mate and you, being a moderator, should have a wider tolerance level than 0.1% 
	

	
	
		
		

		
		
	


	




 Mike.


 Anyways........... what's all this got to do with a kit amplifier?


----------



## rickcr42

pinkie you need to either take this off line or let it go.i am responding to YOU who seems to insist on telling ME what to do and how i should act.

 don't go there.Talk me in pm or email but let it go


----------



## PinkFloyd

Quote:


  Originally Posted by *rickcr42* 
_pinkie you need to either take this off line or let it go.i am responding to YOU who seems to insist on telling ME what to do and how i should act.

 don't go there.Talk me in pm or email but let it go_

 

I'll let it go (hopefully back to discussing the WNA amp)


 Cheers.

 Edit: Sorry Rick, my intention wasn't to tell you what to do or how you should act and if it came across that way.... apologies.


----------



## raja

Hi Mike and Rick,

 hey look, I had to stand by what I myself had found to be true, it wasn't a lie so I had to defend my stance. Just like Rick felt he had to. Anyway it's behind us now and I feel that people, if they are interested in the topic can go back read the responses and figure it out for themselves. I try very hard not to insult people in my posts as I think that is too low. I don't think this is a thread to see who can write the most intelligent posts, but rather a place to share info. I think we can agree to disagree, without having to hate people. 

 I'm quite interested to see how this amp would sound with a single ended mosfet follower, and I may give this a bash in the future as I have adequate heatsinks lying around......

 Thanks
 Raja


----------



## Alick

After a damn fine meal out, I returned home last night and settled down with a glass of whisky to have a proper listening session with my new WNA which by then had ten hours burn-in on the clock. My set-up is a Slim Devices Squeezebox (playing FLAC files), M-Audio 2496 SuperDAC, the WNA and Grado SR-80's. Gradual upgrades have each provided appreciable improvements (X-Can V2, upgrade to Mullards, purchase of DAC) and I was hopeful but apprehensive about the WNA. I trust Mikes judgement (he was right about the Mullards), but I did have reservations about the introduction of the output capacitors and the use of the bog-standard wall-wart PSU. What the hell, it was fun to build, relatively cheap and if I didn't like it, I could always get most of my money back on e-Bay.

 My concerns evaporated as soon as I started to listen, If this thing continues to improve with use/burn-in, I'll be well pleased. The sound after just ten hours is superb. I started off with an album I always use for new gear as (a) I know it backwards, (b) it has a great mix of electric and acoustic instrumentation and lovely vocal harmonising and (c) it's a favourite - Hazeldine's "How Bees Fly". What can I say - the amp sounds "fast" (which I suppose has a lot to do with the slew rate of the op-amp) plucking sounds "pluckier" and strumming "strummier" if that makes sense. 
	

	
	
		
		

		
		
	


	




 I could position players more specifically than before in my minds eye and, even on an album I know intimately, there were details I hadn't noticed before. The "grainy" sound some people mention with the X-Can was gone (if I'm identifying the right effect) and the bass performance is way beyond anything the MF could produce - not only bass "grunt", but detail as well. Above all , I got lost in the music - and that's what counts.

 I'm taking every opportunity to add more hours and the Squeezebox is playing stuff with the headphones in a cupboard as we speak. I can't wait till next weekend when there will be substantially more hours burn-in completed.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_After a damn fine meal out, I returned home last night and settled down with a glass of whisky to have a proper listening session with my new WNA which by then had ten hours burn-in on the clock. My set-up is a Slim Devices Squeezebox (playing FLAC files), M-Audio 2496 SuperDAC, the WNA and Grado SR-80's. Gradual upgrades have each provided appreciable improvements (X-Can V2, upgrade to Mullards, purchase of DAC) and I was hopeful but apprehensive about the WNA. I trust Mikes judgement (he was right about the Mullards), but I did have reservations about the introduction of the output capacitors and the use of the bog-standard wall-wart PSU. What the hell, it was fun to build, relatively cheap and if I didn't like it, I could always get most of my money back on e-Bay.

 My concerns evaporated as soon as I started to listen, If this thing continues to improve with use/burn-in, I'll be well pleased. The sound after just ten hours is superb. I started off with an album I always use for new gear as (a) I know it backwards, (b) it has a great mix of electric and acoustic instrumentation and lovely vocal harmonising and (c) it's a favourite - Hazeldine's "How Bees Fly". What can I say - the amp sounds "fast" (which I suppose has a lot to do with the slew rate of the op-amp) plucking sounds "pluckier" and strumming "strummier" if that makes sense. 
	

	
	
		
		

		
		
	


	




 I could position players more specifically than before in my minds eye and, even on an album I know intimately, there were details I hadn't noticed before. The "grainy" sound some people mention with the X-Can was gone (if I'm identifying the right effect) and the bass performance is way beyond anything the MF could produce - not only bass "grunt", but detail as well. Above all , I got lost in the music - and that's what counts.

 I'm taking every opportunity to add more hours and the Squeezebox is playing stuff with the headphones in a cupboard as we speak. I can't wait till next weekend when there will be substantially more hours burn-in completed. 
	

	
	
		
		

		
		
	


	


_

 

Nice one Alick..... I was very wary of the output caps myself but went down the route recommended by the designer of the circuit and I'm glad I did. I concur with your initial impressions but would go as far as to say the WNA beats the likes of the MF X-Can, Creek OBH 11SE etc. hands down . The WNA, quite simply, amplifies the source and doesn't present the sound through a rose tinted lense like the majority of amps I've heard.

 As far as I'm concerened the lid will remain bolted down on my amp and I won't be trying out any other tweaks...... I'm over the moon with the sound.

 My part in this thread is done and dusted......... the next time I post anything regarding this amp will be in the "amplification" section after I have fully evaluated it and listened to it. I'll also upload my findings to Rock Grotto

 Regards

 Mike.

 Note: Before I do my write up both Duncan and Nigel will have a week with my WNA and they will report on their findings.


----------



## PinkFloyd

regarding the resistors I read into Dr. White's stance on them the wrong way he has pointed out that:

 *"The construction of resistors, in the broadest sense, ( and their value, of course ) does affect their noise contribution, but with headphone amplifiers the signal levels are sufficiently high that this is not really a consideration". 

 "This was only meant to apply to resistor generated noise, as I believe there are some circumstances where low tempco resistors can benefit sound quality in headphone amplifiers."*


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I did have reservations about the introduction of the output capacitors and the use of the bog-standard wall-wart PSU._

 

Hey Alick,

 I've just been reading up on Dr. White's PSUCAS cascode power supply kits and one of those would certainly be better than the standard wall-wart. A heftier price over and above the standard wallwart (£60for the standard PSU and £80 for the audiophile kit) but it may be an avenue you could go down at a later date. I'll probably order a PSUCAS PSU kit one of these days 
	

	
	
		
		

		
		
	


	





 The description, taken from WNA's catalogue is:

*Cascode Power Supply ( New Version )*
The PSUCAS low current ( <1A ), regulated power supply uses innovative circuitry to provide even better performance than its predecessor, without any of the drawbacks inherent in conventional regulated power supplies. The PSUCAS is normally configured to give jumper selectable outputs of either ±15V or ±24V, but the output can be set to any figure from ±3V to ±35V by altering the value of two resistors. The new version is completely "dual mono", with bridge rectification for each supply rail and polypropylene snubber capacitors across each ultra-fast, soft recovery rectifier diode. The printed circuit board also has connections for power on light emitting diodes.
 The vast majority of regulated power supplies use a simple feedback loop to continually correct the output voltage, which would otherwise tend to rise to the input value. The triangular correction waveform appears at the output of the regulator superimposed on the "pure" DC output. The correction waveform will be attenuated, but not eradicated, by the filter capacitors usually present at the output of the regulator, and can be easily observed by hooking an oscilloscope up to the output of the vast majority of regulated power supplies. The correction waveform varies from high audio to radio frequency depending on the speed of the feedback loop. Low speed feedback loops can introduce intermodulation distortion into any proximate audio circuitry. High speed feedback loops keep the output impedance of the regulator low at high frequencies but produce higher levels of insidious rf pollution ( because the filter capacitors are less effective at rf ) which will adversely affect any nearby audio circuitry. Conventional regulated power supplies should therefore be enclosed in shielded enclosures and kept well away from any low level audio circuitry.
 If it were possible to keep the difference between the input and output voltages of the regulator constant then the amplitude of the correction waveform would be zero. In this case the power supply output would contain no corruption and closely approximate a battery power supply. This is exactly how the cascode power supply operates; innovative circuitry keeps the input to output differential voltage of the voltage regulator constant, in the same way that the upper transistor of a cascode pair shields the lower transistor from collector voltage variations. All nasties , such as noise and ripple, on the output of the PSUCAS regulated power supply are at least 90dB down.
 The standard cascode power supply uses a custom-made toroidal transformer and fast, soft recovery rectifier diodes to output around 100mA on each rail at ±15V or around 200mA on each rail at ±24V. It can be used for the op-amps on MOS125/250 power amplifiers, for the stereo phono stage, for up to four ( or eight, if larger heatsinks are fitted ) active crossover boards, and as a general purpose audio power supply. Higher rated transformers capable of providing up to 1A on each rail are available on request. The power supply pcb is typically 28mm high with the smoothing capacitors installed. The transformer can be sited underneath or to the side of the pcb.

 Sounds pretty good


----------



## PinkFloyd

Quote:


  Originally Posted by *PinkFloyd* 
_
 My part in this thread is done and dusted......... the next time I post anything regarding this amp will be in the "amplification" section after I have fully evaluated it and listened to it._

 

Heh..... that lasted about 10 minutes


----------



## jnewman

And hopefully you'll STAY involved in the thread... I just got a note from David White, and my PCB is on the way! Hopefully I won't have TOO many questions for you, but I'm sure I'll have SOMETHING to ask you 
	

	
	
		
		

		
		
	


	




.

 Jimmy.


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_And hopefully you'll STAY involved in the thread... I just got a note from David White, and my PCB is on the way! Hopefully I won't have TOO many questions for you, but I'm sure I'll have SOMETHING to ask you 
	

	
	
		
		

		
			





.

 Jimmy._

 

On its way already Jimmy?? Whooooooa! that was very fast service indeed.

 Nice one


----------



## omi2

finally received the pcb from wna, poor postal service, posted on the 16th and I only just received it!?! 10 days for 1st class recorded 
	

	
	
		
		

		
		
	


	




 had a quick look and skim through, looks pretty straight forward, give it a good go over the weekend and hopefully all goes well 
	

	
	
		
		

		
		
	


	




 for some strange reason it seems an awfully lot smaller than i thought it would be based on the pics posted (silly enough i ignored the scale/rule you placed pink floyg)


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_On its way already Jimmy?? Whooooooa! that was very fast service indeed.

 Nice one 
	

	
	
		
		

		
		
	


	


_

 

Sure is - he shipped it on Saturday and said I ought to be getting it around Wednesday or Thursday. Thanks again for your help making this happen!

 Jimmy.


----------



## PinkFloyd

Quote:


  Originally Posted by *omi2* 
_finally received the pcb from wna, poor postal service, posted on the 16th and I only just received it!?! 10 days for 1st class recorded 
	

	
	
		
		

		
		
	


	




 had a quick look and skim through, looks pretty straight forward, give it a good go over the weekend and hopefully all goes well 
	

	
	
		
		

		
		
	


	




 for some strange reason it seems an awfully lot smaller than i thought it would be based on the pics posted (silly enough i ignored the scale/rule you placed pink floyg)_

 

That's terrible service from the post office... 10 days?? wow. Recorded packages usually arrive the next day...... where do you live, in the outer Hebrides? 
	

	
	
		
		

		
		
	


	




 The board is pretty compact and you probably imagined it to be bigger due to the size of the photos I took. I like the size of it as it means you can house it into a sleek enclosure instead of those brick Sh+thouses you have to use for the Chiarra 
	

	
	
		
		

		
		
	


	




 I think a headphone amp should be as small as possible, those things that are the size of a microwave oven just don't look right 
	

	
	
		
		

		
		
	


	




 One thing I did notice about the boards is the top quality build quality, they are made of fibre glass, roller tinned, solder masked on both sides, and have component outlines and identifiers silk screened onto the top surface of the board..... believe me, you'll have a hard job lifting the pads on those beauties.

 The instructions are very straight forward omi2 and it's just like painting by numbers. pay particular attention to the orientation of the diodes and transistors (clearly marked on the board) and check each resistor with an ohmeter before fitting them (don't just assume that if the bag is marked 330R that it will contain a 330R always check for yourself) 

 You shouldn't run into any difficulties (famous last words!) but if you do they'll generally be simple things such as wiring the headphone socket up the wrong way........ I did that last week and ended up with a very strange sound indeed 
	

	
	
		
		

		
		
	


	




 Dr. White e-mailed me earlier on just to point out the following...... it may be obvious to some but to others it may not be so here goes:

* "A trap for the unwary worth mentioning if you build the headphone amplifier into a metal box, AND bolt the phono input sockets directly to the case ( i.e. no insulation ), AND power the amp via the rail splitter, AND you use a power connector bolted to the case. In this instance the power connector must be one where both terminals are insulated from the mounting sleeve, otherwise one of the power supply rails will be shorted to ground thereby blowing either Tr3 or Tr4. Any non split rail power supply , such as a plug top, used with the headphone amplifier must be truly floating and neither side of it should be connected to a metal case."  *

 If you're using a case with ABS plastic panels then the above doesn't apply but if you're using an all metal enclosure then be sure to use the insulating washers that come with the RCA sockets and use an insulated DC socket.

 The OSCON caps are still a no no with the LM6171 and should not be used.

 All the best with your building and have fun!

 Regards.

 Mike. 

 PS: I've uploaded some of Dr. White's suggestions and comments to http://www.rock-grotto.co.uk/whitenoiseaudio.htm in the "tweaks & Tips" section. I'll add more info to that page when I have the time to get around to it, if anybody else has got anything they'd like to add then PM me and I'll include your tweaks / tips to that page. I've got 50MB of space to fill on that site so the more articles the merrier!


----------



## PinkFloyd

I know I said that the lid would be welded down on my WNA and that, as far as I was concerned, was that......... a truly great headphone amp kit at a truly reasonable price blah blah...... Well......... something has been suggested and I'm wondering whether to give it a go 
	

	
	
		
		

		
		
	


	




"Use a pair of headphone amplifier boards in a balanced configuration. This doubles the speed of the amplifier, halves what little distortion there is, and will probably sound even better than the standard, unbalanced configuration."  

 I'm more than happy with the amp as it stands (and then some) but that suggestion, however plausible, means buying 2 boards from WNA which, in effect doubles the price of the amp kit.

 Has anybody tried using 2 boards in a balanced configuration and, if so, doew it make "that" much of an improvement (if any) ?

 Best.

 Mike.

 NOTE: the "balanced configuration" suggestion was not from Dr. White.


----------



## omi2

Hello all, 

 had sometime today so read through the thread and went through where things go before actually soldering anything on. and making sure I have all the bits, as i need to order a few things and want to lump em together. 

 I came up with some simplistic questions, might be of use to other people who do not have much experience with amps or electronics in general (which i dont 
	

	
	
		
		

		
		
	


	




 )

 Q1:- What/Where do you get the power switch from? Just to check, this is where P3 will be connected to as well as the recessed LED which will act as a power indicator. So any standard switch will do? 

 Q2:- Is there any difference using a wire link compared to a 0 ohm resistor? for the jumpers.

 Q3:- The browndog adaptors are only available from US (Cimarron tech)? Are there an UK resellers, for convenience? (this should be fun soldering some op-amps on...bring out the needle)

 Q4:- Does it matter what gauge the wire is? As I plan to recycle some misc wires from bits and bobs I have, just checking whether this would be a good idea.

 Q5:- With regards to the pot how hard is it to swap them out to test a different ones? As I got a bag of misc ones from my technician. So would prefer to make a choice first before soldering them on (as I really hate desoldering)

 Thats about it, as everything looks nice and set. Gonna start work when the last bits i'm missing arrive. plus my hand injury to heal, kinda hard to solder with 1 hand 
	

	
	
		
		

		
		
	


	




 Thanks in advance, oh yeah was fascinating reading through the posts in this thread, I cannot claim to understand close to everything but did learnt a heck of alot.


----------



## PinkFloyd

Quote:


  Originally Posted by *omi2* 
_Q1:- What/Where do you get the power switch from? Just to check, this is where P3 will be connected to as well as the recessed LED which will act as a power indicator. So any standard switch will do?_

 

I used a DPDT switch from rapid here it is there's no need to connect the LED to the switch, you can connect the LED to P4 (P4 gives you a 12 volt 100mA feed)

  Quote:


  Originally Posted by *omi2* 
_Q2:- Is there any difference using a wire link compared to a 0 ohm resistor? for the jumpers._

 

None whatsover..... some say zero ohm resistors look prettier that's all

  Quote:


  Originally Posted by *omi2* 
_Q3:- The browndog adaptors are only available from US (Cimarron tech)? Are there an UK resellers, for convenience? (this should be fun soldering some op-amps on...bring out the needle)_

 

I've got some AD8610, AD825 and Ad8065 on Bdogs for sale at the moment so if you're interested PM me.

  Quote:


  Originally Posted by *omi2* 
_Q4:- Does it matter what gauge the wire is? As I plan to recycle some misc wires from bits and bobs I have, just checking whether this would be a good idea._

 

Sounds like a very eco friendly way of wiring the amp up 
	

	
	
		
		

		
		
	


	




 As long as the wire fits into the holes on the board it'll be fine. I think I used something like 16/0.2mm

  Quote:


  Originally Posted by *omi2* 
_Q5:- With regards to the pot how hard is it to swap them out to test a different ones? As I got a bag of misc ones from my technician. So would prefer to make a choice first before soldering them on (as I really hate desoldering)_

 

pretty damned impossible to try them out without soldering them but I suppose you "could" attach small crocodile clips or something onto the end of the signal wires and clamp them onto the legs of the pot


----------



## Alick

Quote:


 you can connect the LED to P4 (P4 gives you a 12 volt 100mA feed) 
 

Why didn't I think of that? 
	

	
	
		
		

		
		
	


	



  Quote:


 pretty damned impossible to try them out without soldering them but I suppose you "could" attach small crocodile clips or something onto the end of the signal wires and clamp them onto the legs of the pot 
 

I know you hate soldering, but I'd try the following (with the pot's left loose, not attached to the front panel). Solder the other ends of the leads which will connect to the Potentiometer to the PCB (input) and the input phono's (signal and ground) but leave the cables longer than you need. Then just "tack" solder the pot ends to the pot for testing. After making your selection, you can tidy up the leads and make permanent solder-joints.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Why didn't I think of that? 
	

	
	
		
		

		
		
	


	



_

 

It just seemed a waste to leave that 12V tap unused...... I'm sure it could be put to better uses but it just screamed "LED power source" to me 
	

	
	
		
		

		
		
	


	




 Could be very perverse and use it to power a neon lamp and replace the aluminium lid with a glass / perspex lid.... would look pretty nifty 
	

	
	
		
		

		
		
	


	




 Not exactly in keeping with the less is more philosophy but who gives a hoot, life's too short to spend surrounded by black boxes...... we'll all be living in one soon enough


----------



## raja

Hi,

 With regards to the cascode power supply of white noise, one could go the pcb only route as with the head-amp. Personally I haven't tried the cascode power supply, I'm not sure where it's performance stands in relation to the super regulator that I have (I have a hunch that the refined super reg's beat most other reg's in terms of outright specs). I suppose those of us wanting the best performance are bound to experimentation though. Trouble is neither of the options are cheap when you add up parts etc......

 Thanks
 Raja


----------



## bpribadi

Quote:


  Originally Posted by *PinkFloyd* 
_...The vast majority of regulated power supplies use a simple feedback loop to continually correct the output voltage, which would otherwise tend to rise to the input value. The triangular correction waveform appears at the output of the regulator superimposed on the "pure" DC output. The correction waveform will be attenuated, but not eradicated, by the filter capacitors usually present at the output of the regulator, and can be easily observed by hooking an oscilloscope up to the output of the vast majority of regulated power supplies. The correction waveform varies from high audio to radio frequency depending on the speed of the feedback loop. Low speed feedback loops can introduce intermodulation distortion into any proximate audio circuitry. High speed feedback loops keep the output impedance of the regulator low at high frequencies but produce higher levels of insidious rf pollution..._

 

The 'vast regulated power supplies' mentioned above must be the switching type right? Like the 'light weight' power supply for notebook, mobiles, etc.

 Will the conventional power supply circuit (not the switching type) with heavy transformer and voltage regulator IC such as LM317, LM78XX, etc also introduce the 'correction waveform' mentioned above?

 Thanks!


----------



## jnewman

Well, I got the PCB today and it looks good, so I guess I'll go ahead and order all the little pieces. Unforunately, I'll probably be out of town when the parts arrive and for about a week thereafter, so it'll be a while before I get this working. The PCB is of excellent quality and looks like it'll be pretty easy to work with, and the constuction manual is very clear. Hopefully everything'll get here quickly and I'll be able to start as soon as I get back.

 Jimmy.


----------



## raja

Quote:


  Originally Posted by *bpribadi* 
_The 'vast regulated power supplies' mentioned above must be the switching type right? Like the 'light weight' power supply for notebook, mobiles, etc.

 Will the conventional power supply circuit (not the switching type) with heavy transformer and voltage regulator IC such as LM317, LM78XX, etc also introduce the 'correction waveform' mentioned above?

 Thanks!_

 


 Nope the power supplies mentioned above are the lm317 types, that is how they work, David has tried to produce a regulator which has less of the problems of standard regulators............
 Although the 317's are ok for some......

 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Well, I got the PCB today and it looks good, so I guess I'll go ahead and order all the little pieces. Unforunately, I'll probably be out of town when the parts arrive and for about a week thereafter, so it'll be a while before I get this working. The PCB is of excellent quality and looks like it'll be pretty easy to work with, and the constuction manual is very clear. Hopefully everything'll get here quickly and I'll be able to start as soon as I get back.

 Jimmy._

 

That sure arrived quickly Jimmy, have fun building it man


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_That sure arrived quickly Jimmy, have fun building it man _

 

Will do... the most important part of the amp, of course, is already on its way - my free sample of rainbow foil 
	

	
	
		
		

		
		
	


	




.

 Jimmy.


----------



## bpribadi

Quote:


  Originally Posted by *raja* 
_Nope the power supplies mentioned above are the lm317 types, that is how they work, David has tried to produce a regulator which has less of the problems of standard regulators............
 Although the 317's are ok for some......_

 

Do you have any recommendation for good regulators IC? At least the one that has correction waveform frequency much higher from the audio frequency?

 Thanks!
 Bram


----------



## raja

Hi Bram,

 Try posting at diyaudio.com, or even a different thread at this forum, I don't have enough experience/knowledge to help you. I'm sure I've seen info of smt reg's that may be of superior performance to 317's, but they may have other limitations that need to be highlighted by someone competent at these issues.

 Thanks
 Raja


----------



## PinkFloyd

How are you getting on with yours Alick ?


----------



## StevieDvd

Bad weekend for me with regards amps.

 First of all I was having a go at Opamp rolling and think I may have killed one chip. It only does one channel and sounds full of static. Luckily I have several others to choose from and they all work so it must be the one chip that's gone or it's not a suitable on my cmoy.

 Next I was trying 2 PSU's on my WNA - the supplied one works fine but is a plugtop. I also bought a desktop one which is regulated/linear/more expensive. I fitted the 2.1mm tip which the WNA uses and made sure the polarity was correct on a meter and was the same as the existing connector polarity.

 First scare was seeing the led fade out - till I noticed I had not switched the plug socket on. To compare the 2 PSUs I had to swap them a few times and the second scare was with the new PSU - the WNA failed to power on, but the meter said the PSU was putting out 24v as before. Reconnected with the plugtop amp and all was well.

 Tried the desktop PSU again and it worked fine! A bit puzzling but it was late so I thought I must have left the plug switched off and it was me in error.

 Saturday put the WNA in it's home using the desktop amp and running the lead behind a cabinet to the socket. All worked well and I listened to some CD's before getting dragged out to shop for food.

 Sunday morning I was going to play a new CD to one of the family and the WNA failed to power up again. Tested the PSU and again it was outputting 24v as expected, tried the plugtop and the WNA worked fine.

 Basically the tip that come with the desktop model is a tiny bit shorter than the plugtop one, so the WNA is using the supplied PSU from now on.

 A small thing (the tip that is) causing so much hassle, on the testing side I could not detect a difference between the 2 PSUs soundwise - perhaps I was too stressed out.

 Status
 ======
 WNA still running in. 
 Headsave Classic - running in started. AD8620 fitted by Norm as standard.
 Cmoy Opamp rolling - giving the OP297 a weeks trial (replacing an OP2132PA) - larger case to allow 2 x 9v batteries to hopefully improve sound ordered.

 Team WNA
 Team Headsave Classic
 Team Cmoy
 Team Toomanypsus


----------



## Alick

Quote:


 How are you getting on with yours Alick ? 
 

It's wonderful!

 A good bit more unaccompanied burn-in last week and a decent listening session on Saturday night convinced me that this is the best amp I have ever heard - by a good margin. It continues to improve too - I'm wondering how good it's going to get?

 I'm rediscovering my music collection and hearing detail that I've just never noticed before. I'm not always talking about subtle detail either - there's a lot of "how in the name of hell did I never notice that before" going on. The sound stage is much more "precise" than with the MF - the placing of individual band members is effortless and where some instruments "merged" before, I can position and clearly follow either of two fiddles, guitars or whatever in pieces. All this without losing the entertaining and engaging qualities of the music. 
	

	
	
		
		

		
			





 My lid is firmly fixed on now. Unfortunately, I've got to tear myself away for a week in the sun (life's a bitch). It's there to look forward to when I get back though...


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_First of all I was having a go at Opamp rolling and think I may have killed one chip. It only does one channel and sounds full of static. Luckily I have several others to choose from and they all work so it must be the one chip that's gone or it's not a suitable on my cmoy._

 

What chip was it Steve?

  Quote:


  Originally Posted by *StevieDvd* 
_Next I was trying 2 PSU's on my WNA - the supplied one works fine but is a plugtop. I also bought a desktop one which is regulated/linear/more expensive. I fitted the 2.1mm tip which the WNA uses and made sure the polarity was correct on a meter and was the same as the existing connector polarity. 

 First scare was seeing the led fade out - till I noticed I had not switched the plug socket on. To compare the 2 PSUs I had to swap them a few times and the second scare was with the new PSU - the WNA failed to power on, but the meter said the PSU was putting out 24v as before. Reconnected with the plugtop amp and all was well.

 Tried the desktop PSU again and it worked fine! A bit puzzling but it was late so I thought I must have left the plug switched off and it was me in error.

 Saturday put the WNA in it's home using the desktop amp and running the lead behind a cabinet to the socket. All worked well and I listened to some CD's before getting dragged out to shop for food.

 Sunday morning I was going to play a new CD to one of the family and the WNA failed to power up again. Tested the PSU and again it was outputting 24v as expected, tried the plugtop and the WNA worked fine.

 Basically the tip that come with the desktop model is a tiny bit shorter than the plugtop one, so the WNA is using the supplied PSU from now on.

 A small thing (the tip that is) causing so much hassle, on the testing side I could not detect a difference between the 2 PSUs soundwise - perhaps I was too stressed out._

 

I've got plenty of 2.1mm DC plugs Steve, I'll send you one and you can solder it onto the desktop PSU.... it'll be a perfect fit.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_What chip was it Steve?._

 

From memory it was the AD826AN, I've placed the chips in a preliminary order in the anti-static case.

 The OP297 & AD823 are near the top - the AD826 is in the failed section on its own.

  Quote:


  Originally Posted by *PinkFloyd* 
_I've got plenty of 2.1mm DC plugs Steve, I'll send you one and you can solder it onto the desktop PSU.... it'll be a perfect fit._

 

Great thanks that way I don't need to heatshrink the tips on - much appreciated.


----------



## raja

Hi Steve,

 Forgive me for saying this but isn't ad826an a dual opamp?
 You should be using the single types like ad825.......


 Thanks
 Raja


----------



## JHouser

Does anyone know if the WNA lives well with lower ohm Cans? ie Grados? Is this a good match for a pair of HP-1000s? Thanks!

 Jonathan-


----------



## StevieDvd

Quote:


  Originally Posted by *raja* 
_Hi Steve,

 Forgive me for saying this but isn't ad826an a dual opamp?
 You should be using the single types like ad825.......


 Thanks
 Raja_

 

I need to check the actual chip as I'm going from memory - will do that when I get home later this evening. Probably me quoting the wrong number, 825/826 just a digit out!!


----------



## Alick

Quote:


 Does anyone know if the WNA lives well with lower ohm Cans? ie Grados? 
 

 Works superbly with my SR-80's - see my last couple of posts in this thread.


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi Steve,

 Forgive me for saying this but isn't ad826an a dual opamp?
 You should be using the single types like ad825.......


 Thanks
 Raja_

 

It's a dual opamp he needs in a cmoy Raja, drop in replacements for an OPA2132.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_It's a dual opamp he needs in a cmoy Raja, drop in replacements for an OPA2132._

 

Sorry for confusion - the opamp rolling was on a cmoy like Pinkfloyd has stated above. I would not even think of opamping the WNA .....

 ..... yet 
	

	
	
		
		

		
		
	


	




 Most opamp numbers are just numbers to me at the moment.

 Steve

 Edit s I said useless with the numbers. I'm testing the OP297 in the cmoy and the one that does not work properly is the AD826AN


----------



## JHouser

Quote:


  Originally Posted by *Alick* 
_Works superbly with my SR-80's - see my last couple of posts in this thread._

 

That's great to hear. Thanks to both you and Mike for the detailed discription of your experience with the WNA. My Wallet is climbing up on my desk as we speak. Cheers and good luck with the rest of the burn. BTW, Alick, have you made the same tweaks as Mike on yours? 

 Thanks again!

 Jonathan-


----------



## Alick

Quote:


 BTW, Alick, have you made the same tweaks as Mike on yours? 
 

Yes - I think all of them. I used LM6171's with the associated component changes including non-polar 25uF electrolytic output capacitors and the Class "A" biasing. Mike's amp probably has a slight edge as he used rainbow tape and a blue LED 
	

	
	
		
		

		
		
	


	




 .

 Seriously, Mikes advice and more importantly, trail-blazing with the mod's was invaluable - almost as helpful as him sending me odd components by post every other day 
	

	
	
		
		

		
		
	


	




 .


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_
 Seriously, Mikes advice and more importantly, trail-blazing with the mod's was invaluable_

 

I'd just like to point out that all the modifications were the hard work of Dr. White and my "trail blazing" consisted of nothing more than communicating with him on a daily basis and reporting on his latest mods in this thread.

 Dr. White is the trail blazer........ I was only the bearer of the latest developments (a messenger) 


 All the best.

 Mike.

 PS: I'll never be allowed to forget Rainbow foil will I?


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_PS: I'll never be allowed to forget Rainbow foil will I? 
	

	
	
		
		

		
		
	


	


_

 

Heh, nope... And I got MY rainbow foil yesterday, so your WNA might have some competition 
	

	
	
		
		

		
		
	


	




 .


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Heh, nope... And I got MY rainbow foil yesterday, so your WNA might have some competition 
	

	
	
		
		

		
		
	


	




 ._

 

Be sure to listen to the WNA without the Rainbow foil attached first and then listen to it with foil attached......... you may be seriously surprised Jim.


----------



## JHouser

ok guys. I'm having a hard time getting a hold of David White. Sounds like from everyone else's post's he is very responsive. Is e-mail the best way to contact him? Trying to get my hands on a PCB... 
	

	
	
		
		

		
		
	


	





 Jonathan


----------



## jnewman

Quote:


  Originally Posted by *JHouser* 
_ok guys. I'm having a hard time getting a hold of David White. Sounds like from everyone else's post's he is very responsive. Is e-mail the best way to contact him? Trying to get my hands on a PCB... 
	

	
	
		
		

		
		
	


	





 Jonathan_

 

Well, he is very responsive in that he ALWAYS responds and ALWAYS with helpful comments - but my average turnaround time was something like 2 days. He's a busy guy 
	

	
	
		
		

		
		
	


	




.

 Jimmy.


----------



## raja

Hi,

 Well I managed to get my amp with lm6171's running properly today, and I can confirm that Mike is right, they are a very substantial improvement over all the other opamps, even with the output caps in place. Only problem now is that I can't use this as a buffer for my power amp anymore, the dc offset is a little to high and triggers the protection circuit. I think the protection circuit does not allow sources with above 10mv offset to be connected. I have tried increasing the values of r2 and r3 to 3k3 and 10k, but the problem persists. Cap size is 4.7uf although I have tried larger 25uf caps too. The amp works fine with my headphones, I think the dc offset is around 24mv or so. Out of interest can anyone who has the amp in a similar config, report the offset before and after the caps?

 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi,

 Well I managed to get my amp with lm6171's running properly today, and I can confirm that Mike is right, they are a very substantial improvement over all the other opamps, even with the output caps in place. Only problem now is that I can't use this as a buffer for my power amp anymore, the dc offset is a little to high and triggers the protection circuit. I think the protection circuit does not allow sources with above 10mv offset to be connected. I have tried increasing the values of r2 and r3 to 3k3 and 10k, but the problem persists. Cap size is 4.7uf although I have tried larger 25uf caps too. The amp works fine with my headphones, I think the dc offset is around 24mv or so. Out of interest can anyone who has the amp in a similar config, report the offset before and after the caps?

 Thanks
 Raja_

 


 Hi Raja,

 The LM6171's are a mega improvement over the AD / TI variants aren't they? Now, if the output caps can be dispensed with I can't begin to imagine just how good this amp could get! I'm satisfied with the output caps in place but will certainly remove them if, and when, a workaround has been designed by Dr. White.

 I'm afraid I can't measure the DC offset at the moment as the GSP PSU1 power supply I was using has been reterminated with a bayonet locking DC connector and the WNA is awaiting a new custom made linear PSU.

 Mike.


----------



## JHouser

To add a DAC from aos to the WNA. Would it be possible?

http://www.aoselectronics.com/ppa_db.html

 Jonathan-


----------



## raja

Quote:


  Originally Posted by *JHouser* 
_To add a DAC from aos to the WNA. Would it be possible?

http://www.aoselectronics.com/ppa_db.html

 Jonathan-_

 


 Hi,

 I don't see why not.....

 Thanks
 Raja


----------



## raja

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Raja,

 The LM6171's are a mega improvement over the AD / TI variants aren't they? Mike._

 

Yes the difference is amazing, considering there are output caps.

 all the best,

 Raja


----------



## ppl

out of 10 pages in this thred lots of nice photos and no schematic, gee


----------



## peranders

Quote:


  Originally Posted by *ppl* 
_... and no schematic, gee_

 

This is a choice of David White but I think he doesn't have so much to loose if he publish the schematics but only he decides that. I'm also curious of his designs but only as a reference.


----------



## PinkFloyd

Quote:


  Originally Posted by *ppl* 
_out of 10 pages in this thred lots of nice photos and no schematic, gee_

 

Hi ppl,

 If you buy a PCB then the schematic diagrams are sent along with it.

 Mike.


----------



## raja

Hi,

 We have to respect David's wishes either way, I have never asked him if I can post his designs, but I remain confidential unless he tells Mike or myself otherwise. Some of the circuitry is unique, and it wouldn't be good business sense to spill it everywhere. The pcb prices are fair considering the work that's gone into them. 
	

	
	
		
		

		
		
	


	





 Thanks
 Raja


----------



## ppl

Ok... Ok... I get the point.
 I used to give freely to this and other Fourms then after some people would copy my work and claim its there own and then argue that its not unique anyway because part or parts can be found in the public domain and this gives them the right to copy and claim as there’s even if its copied down to the exact component values and brands. It is a shame we have people that do this and thus have made more and more designer’s protective of there work. This age of Intellectual property was not as valued in my Day as it is now in my day we copied our friends music and no one was concerned and no the RIAA did not have 12 year olds pay thousands of dollars for doing so. I understand times are a changing and intellectual property is extremely valuable. I am a learning the new ways now mums the word.

 Well first off with over 60 years of Electronics to look back on; I assure you everything has been tried at least once. Just like in cooking each ingredient is in the public domain yet a talented chef can use these publicly known ingredients and make the same dish that another chef’s yet it will come out unique due to quantities used and sometime exact brand names in order to get a specific taste. The same applies to any other intellectual work. 

 On the Amp in question since its a DIY project and like myself DIY folks are interested in Designs I would assume that the designer would like to show off his circuit and show any unique elements to its design.

 This Amp appears to be just your basic op amp with a pair of Diode Biased BJT's as an output stage. This is not bad it is a good solid design that has been used for over 25 years as a standard default headphone driver. This type of circuit is nothing to be ashamed about (One reason someone keeps the design confidential) so it just struck me odd that a DIY design would publish such little technical information is my point. I do however respect anyone that wishes to keep a design private however this is really hard in a DIY unit. All the old Dynaco’s and Heath Kits had published manuals and you cold obtain a copy prior to Purchase so as to decide if the Kit is too complex for your skill level.


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi,

 We have to respect David's wishes either way, I have never asked him if I can post his designs, but I remain confidential unless he tells Mike or myself otherwise. Some of the circuitry is unique, and it wouldn't be good business sense to spill it everywhere. The pcb prices are fair considering the work that's gone into them. 
	

	
	
		
		

		
			






 Thanks
 Raja_

 

Indeed, Dr. White supplies the Schematics with the PCB / Kit and that's good enough for me. His business is to provide cost effective, innovative and sonically superior audio products in kit form..... to publish his designs in the public domain would be like shooting himself in the foot. 

 I'm sure his designs will eventually be leaked in #head-fi but there is no reason why a designer should feel obliged to publish his efforts on the WWW.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *ppl* 
_Ok... Ok... I get the point.
 I used to give freely to this and other Fourms then after some people would copy my work and claim its there own and then argue that its not unique anyway because part or parts can be found in the public domain and this gives them the right to copy and claim as there’s even if its copied down to the exact component values and brands. It is a shame we have people that do this and thus have made more and more designer’s protective of there work. This age of Intellectual property was not as valued in my Day as it is now in my day we copied our friends music and no one was concerned and no the RIAA did not have 12 year olds pay thousands of dollars for doing so. I understand times are a changing and intellectual property is extremely valuable. I am a learning the new ways now mums the word.

 Well first off with over 60 years of Electronics to look back on; I assure you everything has been tried at least once. Just like in cooking each ingredient is in the public domain yet a talented chef can use these publicly known ingredients and make the same dish that another chef’s yet it will come out unique due to quantities used and sometime exact brand names in order to get a specific taste. The same applies to any other intellectual work. 

 On the Amp in question since its a DIY project and like myself DIY folks are interested in Designs I would assume that the designer would like to show off his circuit and show any unique elements to its design.

 This Amp appears to be just your basic op amp with a pair of Diode Biased BJT's as an output stage. This is not bad it is a good solid design that has been used for over 25 years as a standard default headphone driver. This type of circuit is nothing to be ashamed about (One reason someone keeps the design confidential) so it just struck me odd that a DIY design would publish such little technical information is my point. I do however respect anyone that wishes to keep a design private however this is really hard in a DIY unit. All the old Dynaco’s and Heath Kits had published manuals and you cold obtain a copy prior to Purchase so as to decide if the Kit is too complex for your skill level._

 

EDIT: I should really read what people are saying before responding...... apologies PPL.


----------



## xtreme4099

Quote:


  Originally Posted by *PinkFloyd* 
_I'm sure Dr. White will respond to your quite, extraordinary, post in due course ppl. You've basically forced a public showing of the WNA schematic and I think that's extremely bad form on your part. 

 Mike_

 


 how is this bad form?


----------



## ppl

No my intent was not to force anyone to do anything i did explain why i fully understand his wanting to keep it out of the Plublic domain it just struck me odd that this is the only Kit i know of that dose that. If the designer wises to contact me privitely i might evean offer sugestions for inproving his circuit for no charge. my sugestion to the designer is along the lines of what audio kits dose http://www.audiokits.com/downloads.asp

 Now pinkie you know i am not one to dance around others sensibilities i say what i feel at the moment. This has on more than one ocasion resulted in someone taking offence however offencive was never my intent at any time to come off offensive however this appears to happen alot, Oh well


----------



## PinkFloyd

Edit: Too much whisky


----------



## xtreme4099

give the feller a break pinkie ... you very well know what he's sayin'


----------



## ppl

No im not Drunk and my understanding of http://www.kli.org/ is ok whats with the hostility all I asked is why no schematic and now this turned into a Drama


----------



## PinkFloyd

Quote:


  Originally Posted by *ppl* 
_No im not Drunk and my understanding of http://www.kli.org/ is ok whats with the hostility all I asked is why no schematic and now this turned into a Drama_

 


 You've seen the design can you please lay your thoughts down?

 EDIT: Apostrophe missing.


----------



## ppl

The Circuit is as I suspected and it’s nothing to be ashamed of. I know of at least two current production headphone amps that use almost the same circuit this being an op amp driving a a complementary pair of output transistors. This could be improved by replacing the two diodes with transistors connected in a Diamond buffer configuration. This will result in more current drive to the load and allow the Bias current to better control crossover Distortion. The Transistors can be small signal types like 2N2222A and 2N2904 or equiv. like BC550 and BC560. The important spec is Ft and DC Beta, you want as much of each as possible.


----------



## PinkFloyd

Quote:


  Originally Posted by *ppl* 
_No im not Drunk and my understanding of http://www.kli.org/ is ok whats with the hostility all I asked is why no schematic and now this turned into a Drama_

 

Phillip,

 My sincerest apologies, I completely misconstrued your comments and was under the influence of a certain Scottish beverage at the time.

 Your comments probably did look like they were written in Klingon at the time but, in the light of day, I can see that it was me who made a total arse of myself.

 Mike.


----------



## Kenny12

lol i thought this was some kinda amp to amplify white noise lol..

 anyway how does this compare to pimeta? might explore my diy side again after exams 
	

	
	
		
		

		
		
	


	




 btw the crossfeed is working a treat pink


----------



## ppl

I understand and its all good Mike


----------



## Alick

Quote:


 Too much whisky 
 

I'm having trouble with this concept.


----------



## jnewman

Mike asked for an update on my progress on the WNA in another thread, so here we go:

 I've been pretty delayed because of a lot of complications lately. I had to leave town for all of last week, and didn't want to order parts and have all kinds of electronics components sitting in a box on my doorstep for three or four days getting rained on, so I've waited to order until I got back. But now I'm moving back up to school in five days, so I have to order the parts and have them shipped up there, and I'm probably not going to get everything settled in there for as much as a week or week and a half, so it looks like I'll be getting started in a week or two. I hope to have the amp done in early/mid September - I wish I could get started sooner, but there's just no way that I can. We'll see how it goes, and I'll post back here as soon as parts start arriving.

 Jimmy.


----------



## Alick

It's irritating when life interferes with Head-Fi pursuits. Mine took a little longer to build than I'd hoped, but I suspect you'll find it's well worth the wait. Mine just keeps on surprising me with how good it is. Sometimes when listening, I get a kind of double whammy - a "wow, this is unbelievably good" quickly followed by a "wow - and I built it!"


----------



## Earwax

Jimmy, I'll ask you since you're in the U.S., how much do you expect all the parts to run? And how much was the board with postage to the U.S.?


----------



## jnewman

Quote:


  Originally Posted by *Earwax* 
_Jimmy, I'll ask you since you're in the U.S., how much do you expect all the parts to run? And how much was the board with postage to the U.S.?_

 

I'm going a bit overboard on the parts for this thing. First of course is the board, which is actually very expensive... it's 30 pounds or something like that, ends up being about $50.

 Apart from that, I'm going to be using .1% metal films and more expensive polypropylene film caps and black gate electrolytics and teflon-insulated silver-plated stranded-copper internal wire and a bit-more-expensive-than-hammond case (from lansing-enclosures.com) and possibly a fancy illuminated pushbutton switch. Oh, and some rainbow foil, but that was free 
	

	
	
		
		

		
			





. All the parts (not including the board), mostly from mouser with the caps and op-amps coming from other places, the total looks to be around $125-150. Including the board and miscellaneous expenses I'll probably end up a touch under $200 for the whole thing - a bit more than a maxed out pimeta, about equal to a pretty bare-bones PPA, and less than half the cost of putting similar parts into a PPA. I'm probably overspending on this amp, but I want to make it the best I possibly can so I'm going to go ahead and do it.

 Oh. I have a stepped attenuator that is on its way that may or may not end up in with it - if it does, that'd push the total spent up about $100.

 Jimmy.


----------



## raja

Hi,

 if using lm6171's then be careful with the black gate's, they can cause it to motorboat.

 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi,

 if using lm6171's then be careful with the black gate's, they can cause it to motorboat.

 Thanks
 Raja_

 

That's interesting Raja, are they low ESR or what? I'm going to try some ELNA Silmics in mine, hopefully they won't motorboat!


----------



## jnewman

Quote:


  Originally Posted by *raja* 
_Hi,

 if using lm6171's then be careful with the black gate's, they can cause it to motorboat.

 Thanks
 Raja_

 

In the C3/C5 positions or in the bipolar output position? I was going to use N series 10microfarad 50v or 47microfarad 50v bipolars in the output cap spots and FK series 100microfarad 25v caps in the C3/C5 positions. Which (if any) of these will cause problems, and what might be a good alternative? Thank you for your help.

 Jimmy.


----------



## raja

Hi,

 I remeber I tried 35v 100uf rubycon za's after the rail splitter ( I have read somewhere that these are similar to the standard bg's), and I had the same trouble Mike reported with the squealing sounds. David then reported back on this thread that he was using 47uf types (I think oscons), so I tried za's of this value, you can get away with 16v 47uf, better to use as low value voltage rating as possible, this keeps esr down. I have found that adding a 0.1uf film cap between pins 4 and 7 of the lm6171 increase it's stability somewhat. I can run the amp fine with my headphones. Ultimatley I think David should be asked as to what type of caps should be used after the rail splitter, and whether or not low esr types can or should be used at all. I don't think the standard bg's have an ultra low impedence, but once you step over FK type territory and beyond, you're over the border. You can however use bg's as ouput coupling caps. You can certainly try them I suppose, and see what happens......

 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_I'm going a bit overboard on the parts for this thing. First of course is the board, which is actually very expensive... it's 30 pounds or something like that, ends up being about $50._

 

Unfortunately, everything in the UK is pretty expensive thanks to our "democracy" which somehow voted for 17.5% VAT, high fuel duties, massive duties on tobacco, road tax, obscene petrol prices etc. etc. I must have been out of the country when we voted for all that 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *jnewman* 
_I'm going to be using .1% metal films and more expensive polypropylene film caps and black gate electrolytics and teflon-insulated silver-plated stranded-copper internal wire and a bit-more-expensive-than-hammond case (from lansing-enclosures.com) and possibly a fancy illuminated pushbutton switch. Oh, and some rainbow foil, but that was free 
	

	
	
		
		

		
		
	


	




. All the parts (not including the board), mostly from mouser with the caps and op-amps coming from other places, the total looks to be around $125-150. Including the board and miscellaneous expenses I'll probably end up a touch under $200 for the whole thing - a bit more than a maxed out pimeta, about equal to a pretty bare-bones PPA, and less than half the cost of putting similar parts into a PPA. I'm probably overspending on this amp, but I want to make it the best I possibly can so I'm going to go ahead and do it._

 

Even if the price reaches $200 that's only £109 (UK) which is an unreal price for an amp of this quality..... does your $200 factor in a 24V power supply? The constant current diodes (CCD'S) are just plain old current regulating diodes (CRD'S) I don't know why David calls them CCD's? You'll be looking to order the axial varieties example 

 I've got no experience of the black Gate caps in this circuit and have noticed raja's motorboating warning......... Maybe best to go with ELNA cerafines / Silmics?

  Quote:


  Originally Posted by *jnewman* 
_Oh. I have a stepped attenuator that is on its way that may or may not end up in with it - if it does, that'd push the total spent up about $100._

 

That "would" be nice 
	

	
	
		
		

		
		
	


	




 Jimmy.


----------



## raja

Hi,

 the stepped attenuator is nice, last week I managed to pick up a working tvc preamp for £100 from a friend of mine. What a bargain, works better than anything else I have as a volume control for my headphones too, with my cdp no headamp required, sound is a 20% improvement.

 Thanks
 Raja


----------



## PinkFloyd

Quote:


  Originally Posted by *raja* 
_Hi,

 I remeber I tried 35v 100uf rubycon za's after the rail splitter ( I have read somewhere tat these are similar to the standard bg's), and I had the same trouble Mike reported with the squealing sounds. David then reported back on this threadthat he was using 47uf types (I think oscons), so I tried za's of this value, you can get away with 16v 47uf, better to use as low value voltage rating as possible, this keeps esr down. I have found that adding a 0.1uf film cap between pins 4 and 7 of the lm6171 increase it's stability somewhat. I can run the amp fine with my headphones. Ultimatley I think David should be asked as to what type of caps should be used after the rail splitter, and whether or not low esr types can or should be used at all. I don't think the standard bg's have an ultra low impedence, but once you step over FK type territory and beyond, you're over the border. You can however use bg's as ouput coupling caps. You can certainly try them I suppose, and see what happens......

 Thanks
 Raja_

 

The WNA sure is a bit of a prima donna with the LM6171 isn't it? 
	

	
	
		
		

		
		
	


	




 I dropped an LM6172 (dual channel LM6171) into the Graham Slee Solo and it worked first time! The output was not centred properly between the power rails but swapping a 47K resistor for a 43K sorted that in a jiffy.... I just can't understand why the LM6171 in the WNA should be so sensitive of capacitors, I agree that David should recommend a cap for use with the LM6171.

 The last I heard from David regarding my initial warning about using Low ESR caps was this:

 "Built a buffer amp (same as headamp apart from 12V bulb ) for a customer, tested it thoroughly before shipping, but when he powered it up the BD139 in the rail splitter blew taking a bit of track with it. Told him to send it back and lo and behold I'd put my last pair of OSCON SA/SC 100uF 16V caps in the rail splitter! So I replaced the BD139 and tried to replicate the problem. I tried three different power supplies, different input impedances, sine waves, square waves, 33ohm loads, 100ohm loads, no loads, long cable on output, and probably quite a few other things - but no luck. Still an enigma, but your warning about 100uF 16V OSCONs still stands."

 The LM6171 is so good in this amp that it's worth using it but it would be nice to know of a suitable "audiophile" cap which partners well with the LM6171..... a kit amp should never be a hit and miss experience.

 Mike.

 Edit: I'm just using el cheapo 85C dubilier caps in mine and it sounds wonderful....... I expect the ELNA Silmic, from past experience, will make the amp sound even better.


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_Even if the price reaches $200 that's only £109 (UK) which is an unreal price for an amp of this quality..... does your $200 factor in a 24V power supply? The constant current diodes (CCD'S) are just plain old current regulating diodes (CRD'S) I don't know why David calls them CCD's? You'll be looking to order the axial varieties example 

 I've got no experience of the black Gate caps in this circuit and have noticed raja's motorboating warning......... Maybe best to go with ELNA cerafines / Silmics?



 That "would" be nice 
	

	
	
		
		

		
		
	


	


_

 

Thanks for the link to Rapid - everywhere I looked over here only had Central Semiconductors current regulating diodes, and they only went up to 4. mA so I was going to have to parallel a couple of them to get the 5.6mA required. Wouldn't cause any problems, I don't think, just make that bit a little more responsive, but it'd sure look ugly 
	

	
	
		
		

		
		
	


	




. And yeah, I know it's a great deal... I'm sort of going after some of the most expensive parts I can get and it's not going to be too bad.

 Jimmy


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Thanks for the link to Rapid - everywhere I looked over here only had Central Semiconductors current regulating diodes, and they only went up to 4. mA so I was going to have to parallel a couple of them to get the 5.6mA required. Wouldn't cause any problems, I don't think, just make that bit a little more responsive, but it'd sure look ugly 
	

	
	
		
		

		
		
	


	




. And yeah, I know it's a great deal... I'm sort of going after some of the most expensive parts I can get and it's not going to be too bad.

 Jimmy_

 

I think Rapid ship to the US Jimmy, if not I can order them next time I shop at rapid and get them over to you..... no probs.

 Mike.


----------



## raja

Hi,

 You also have to be careful using the head/buffer amp as a line stage, my wna mos 250 doesn't like the amp running with lm6171's, either the dc protection trips, or the amp (mos 250) seems to oscillate. I can only put this down to oscillation of the buffer amp outside the 'hearable' audio range, and because the mos 250 is a wide bandwidth amplifier. This could be due to the caps which are presently oscons 25v 47uf. I suppose someone really needs to do some work and find out just what caps the chips will tolerate. I really did find that the addition of the 0.1uf film caps directly between pins 4 and 7 did make a difference, it may be a good precaution to do this even if everything seems ok. Again I'd prefer if David was able to recommend what value of film cap to use. I remember a post by Thorsten, who said that he usses stcked film caps accross these pins to help keep the lm6171 stable, although I'm not sure of the value he used. I suppose the reason for the unpredictable nature of the amp is because it wasn't really designed for the lm6171. Trouble is it sounds so good with it in place, it's hard to go back once you've tried them. 

 Thanks
 Raja


----------



## raja

Hi,

 You also have to be careful using the head/buffer amp as a line stage, my wna mos 250 doesn't like the amp running with lm6171's, the dc protection trips, or the amp (mos 250) seems to oscillate. I can only put this down to oscillation of the buffer amp outside the 'hearable' audio range, and because the mos 250 is a wide bandwidth amplifier. This could be due to the caps which are presently oscons 25v 47uf. I suppose someone really needs to do some work and find out just what caps the chips will tolerate. I really did find that the addition of the 0.1uf film caps directly between pins 4 and 7 did make a difference, it may be a good precaution to do this even if everything seems ok. Again I'd prefer if David was able to recommend what value of film cap to use. I remember a post by Thorsten, who said that he uses stacked film caps accross these pins to help keep the lm6171 stable, although I'm not sure of the value he used. I suppose the reason for the unpredictable nature of the amp is because it wasn't really designed for the lm6171. Trouble is it sounds so good with it in place, it's hard to go back once you've tried them. 

 Thanks
 Raja


----------



## PinkFloyd

Hi Raja,

 I received an e-mail from David regarding a few of the issues here and here is what he says:

* [size=medium]"Mike,
 Try as I might I've never been able to incite instability in a LM6171 based buffer or headphone amp. The one where my customer blew off some tracking turned out to be because he'd earthed one side of his single ended power supply. If you do this the rail splitter shorts out the power supply! I've tried 100uF 25V bog standard electrolytics, 47uF 16V OSCON SG ( obsolete now ) and SP, 100uF 25V Elna ZA, and 120uF 25V Elna RJH with no problem. The idea of using a film capacitor across the opamp +ve and -ve power pins is a good one - I do this on my tone control stage and use 1uF stacked film caps, the ones with the exposed end metallization. You can also add 100nF ceramic decoupling capacitors between each power supply pin and ground, as recommended by NatSemi, if you wish. With high speed circuitry earthing is important too. I always connect metal cases to the mains protective ground for safety reasons, but I join signal ground to the case in one item of equipment only, usually the source ( CD player, record deck etc ).

 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." [/size] *


----------



## Sewer Guy

I totally agree with David White on the LM 6171. We use them in the video cameras we design, manufacture & sell to the sewer inspection industry. you have to work at making the 6171 unstable. As long as you have the power rails decoupled with .1 or .01 mfd. ceramics, located close to the device you should not have any trouble. I use a 6172, dual version in my chiara. I even removed the 100 pf. caps from the amp. The amp sounds marvelous & will be even better when I get the FET bias ckt. installed.


----------



## PinkFloyd

Hi Bill,

 Do you mean you have to work at making the LM6171 "stable" or you have to work at making it "unstable"


----------



## Sewer Guy

Hi Pinkie: As long as your P.C. layout is good & the +-power rails are bypassed with .1 or .01 mfd. ceramic caps; the 6171 is hard to destabilize.
 The amp not only has great slew rate & freq. response; it is also unity gain stable. This coupled with its transparent sound quality make it an outstanding
 audio op amp; in my humble opinion.

 The funny thing is that National Semi designed it as a high quality video amplifier, originally.


----------



## PinkFloyd

Just thought you guys would be interested, I rolled an LM6171 into the Rail splitter in place of the OPA627BP and the sound is even more controlled, detailed and energetic with the LM6171 in place.

 I don't quite know why this should be the case but it may be something to do with the phenomenal speed of the LM6171 or it could just be a case of chip synergy? Whatever the reason, that's three LM6171's under the bonnet now and the amps sounds superb


----------



## jpmoon

.......to all of the contributors to this thread, especially PinkFloyd, who's rock-grotto was my 'in' point. Building the WNA headphone amp and reading the posts has given me a great deal of entertainment over the last few weeks. I haven't built much in the last few years and it was reassuring to know that others were on the same journey, and that I can still solder.

 The plug top PSU and rail splitter were a definite plus point for me, making the project affordable and self-contained. I've carried out the LM6171 related tweaks and I've just swapped the rail splitter capacitors for Oscons, okay so far. I've upped the gain to 5 (puts 'nice' volume to straight up) and I'm using 10 pence non-polar electrolytics paralleled with 4u7 polypropylene types as output capacitors for the moment. Neither my modest source equipment nor my hearing can fault the amp. I've been using the 'tape out' circuit, volume pot and selector switches of my main amp as primitive test gear. The WNA headphone amp is staying in circuit until I can turn it into a full pre-amplifier. Playing about with various recordings, trying to match levels with two volume pots, brought home to me just how much slight changes in absolute level mask all manner of subtleties. I already new this but I'll never say, "This sounds better than that", without a SPL meter, a PPM and some VT type line-up tones.

 You can probably tell that I'm more technician than audiophile, "kiss" so you can afford to use the best quality components is definitely my approach and this little project delivers. Cheers John.


----------



## PinkFloyd

Quote:


  Originally Posted by *jpmoon* 
_.......to all of the contributors to this thread, especially PinkFloyd, who's rock-grotto was my 'in' point. Building the WNA headphone amp and reading the posts has given me a great deal of entertainment over the last few weeks. I haven't built much in the last few years and it was reassuring to know that others were on the same journey, and that I can still solder.

 The plug top PSU and rail splitter were a definite plus point for me, making the project affordable and self-contained. I've carried out the LM6171 related tweaks and I've just swapped the rail splitter capacitors for Oscons, okay so far. I've upped the gain to 5 (puts 'nice' volume to straight up) and I'm using 10 pence non-polar electrolytics paralleled with 4u7 polypropylene types as output capacitors for the moment. Neither my modest source equipment nor my hearing can fault the amp. I've been using the 'tape out' circuit, volume pot and selector switches of my main amp as primitive test gear. The WNA headphone amp is staying in circuit until I can turn it into a full pre-amplifier. Playing about with various recordings, trying to match levels with two volume pots, brought home to me just how much slight changes in absolute level mask all manner of subtleties. I already new this but I'll never say, "This sounds better than that", without a SPL meter, a PPM and some VT type line-up tones.

 You can probably tell that I'm more technician than audiophile, "kiss" so you can afford to use the best quality components is definitely my approach and this little project delivers. Cheers John._

 

Hi jpmoon!

 Firstly, welcome to Head-Fi! I would have responded to your first post a lot faster if I had known about it.

 Sounds like you know the hot end of a soldering iron from the cool end and I'm really glad you are happy with the WNA 
	

	
	
		
		

		
		
	


	




 Glad to hear the OSCON's are ok "so far"! I don't know why they played up in my WNA but it sure doesn't like them 
	

	
	
		
		

		
		
	


	




 I'm about to build my 4th WNA and may well build the Cascode PSU to see if it improves the sound quality.......... I'm happy with the £7.50 Stontronics regulated PSU but must find out just "how" much of an improvement (if any) can be gained by powering the amp with a WNA cascode PSU..... 

 All the best.

 Mike.


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_Just thought you guys would be interested, I rolled an LM6171 into the Rail splitter in place of the OPA627BP and the sound is even more controlled, detailed and energetic with the LM6171 in place.

 I don't quite know why this should be the case but it may be something to do with the phenomenal speed of the LM6171 or it could just be a case of chip synergy? Whatever the reason, that's three LM6171's under the bonnet now and the amps sounds superb 
	

	
	
		
		

		
		
	


	


_

 

Are there any changes necessary to drop a LM6171 into the TL071/OPA627 rail splitter position?

 I'm going to try to buy parts in the next few days and that was the last thing I need to iron out. Looks like I'm going to be using .1% resistors, black gates in c3/c5 and output, polypropylene orange drops in film cap spots, lm6171's all around, panasonic evj pot, all stuck in a lansing enclosures case. If all goes well, I'll have it built and running in about two weeks.

 Thanks again for all the help, and I'll report back (with pictures) as I get parts and start putting them in.

 Jimmy.


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Are there any changes necessary to drop a LM6171 into the TL071/OPA627 rail splitter position?

 I'm going to try to buy parts in the next few days and that was the last thing I need to iron out. Looks like I'm going to be using .1% resistors, black gates in c3/c5 and output, polypropylene orange drops in film cap spots, lm6171's all around, panasonic evj pot, all stuck in a lansing enclosures case. If all goes well, I'll have it built and running in about two weeks.

 Thanks again for all the help, and I'll report back (with pictures) as I get parts and start putting them in.

 Jimmy._

 

No changes necessary Jimmy,


 Direct drop in replacement territory.......... LM6171 in the rail splitter section rocks.

 Great to hear from you.......... I was wondering where you were? Keep us posted, I'm building another WNA codename (the Italian Job) and will be uploading detailed pics of the job in progress 

 All the best.

 Mike.


----------



## jnewman

Ok. I just put together a complete parts list from all the different places I'm going to have to order from. Including some quadeutectic solder and some 20ga teflon-insulated silver-plated hookup wire, everything but the board comes to $159.28. This includes:

 IRC .1% 1/4W metal film resistors.
 Central Semiconductors CCD's.
 Phihong 1% line 5% load regulating 1% noise peak-to-peak 24v PSU. (Seems to be equivalent to the $30 Elpac at a little cheaper with slightly more current supply)
 Kobiconn DC power jack.
 3.5mm stereo phone jack (input - going to be using mostly with a PC)
 6.5mm Switchcraft switched phone jack (output)
 Cherry Electronics DPST on-off round rocker switch.
 Super bright green T1 3/4 LED and holder.
 LM6171BIN (8-pin DIP) opamps for all IC's
 .1mF Panasonic ECHS precision PPS film caps
 50K Panasonic EVJ pot
 Standard BD139 and BD140 transistors.
 Standard 1N4148 diodes
 Polished chrome knob.
 100mF 16V H Blackgate caps (C3,C5)
 10mF 50V N Bipolar Blackgate caps (output)
 CE2B63-B1B4 Lansing Enclosure
 20AWG teflon-insulated silver-plated copper hookup wire
 Cardas Quadeutectic Solder

 If anyone wants this all tallied up with prices, parts numbers, and origin in an Excel spreadsheet, let me know and I'll have it shortly for you. Also, am I missing anything? That's everything I can think of. Parts are coming from mouser.com, digikey.com, partsconnexion.com (only good source I could find of blackgates), and lansing-enclosures.com. I'm paying a bit more on shipping spreading things out like this, but I couldn't find any single source that had everything I needed. I'll order the parts in the next few days, get them early next week, and hopefully either do it over that week or that weekend.

 I'll post as soon as I start recieving things.

 Jimmy.


----------



## PinkFloyd

I'm just about to build up an LM6171 based WNA for "X" who is a long standing head-fi member.

 I'll upload ongoing progress reports / pictures to this thread as I work my way through the kit.

 In the meantime, is there anyone who has built a standard WNA who would be willing to assure "X" that he'll get a lot more performance from a WNA than a commercially built amp costing 4 times the price?

 I'm about to build the amp for "X" but it would be great if someone else could outline what's involved in a DIY amp from the parts ordering to the build........... I don't think people appreciate just how much time is needed........

 How long did it take you to build your WNA / PSU in hours (including all the time taken to source and order the components)


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_I'm just about to build up an LM6171 based WNA for "X" who is a long standing head-fi member.

 I'll upload ongoing progress reports / pictures to this thread as I work my way through the kit.

 In the meantime, is there anyone who has built a standard WNA who would be willing to assure "X" that he'll get a lot more performance from a WNA than a commercially built amp costing 4 times the price?

 I'm about to build the amp for "X" but it would be great if someone else could outline what's involved in a DIY amp from the parts ordering to the build........... I don't think people appreciate just how much time is needed........

 How long did it take you to build your WNA / PSU in hours (including all the time taken to source and order the components)_

 


 Not actually HAVING any of the parts yet, and having done a little bit of electronics work but no DIY audio, I'll be happy to outline the parts ORDERING part specifically for the WNA from scratch. You have to at least order the board from David White, and can get everything up to a full kit including basically everything you need. The board and kits come with a pretty good construction manual, a complete parts list, and a schematic. Being from the US, it comes out MUCH cheaper for me to order parts on my own, even for higher quality parts. This necessitated much reading around and looking at numbers and schematics and figuring out what parts to fill what positions with, as well as finding a relatively small number of suppliers to order parts from. Also, I decided to do the full LM6171 mod, which requires a number of changes from the basic parts list, so I had to go through and figure out what all needed to be changed there. After that, it was mostly just a matter of going through and looking up all the parts, getting the correct number of all the different values of resistors, finding the correct value (and size) film and electrolytic capacitors, and little stuff like looking up an enclosure, LED, switch, and knob that I like as well as a good 1/4" headphone jack with the right kind of switching (to bridge signal->ground through a 100ohm resistor when cans aren't plugged in). One problem I ran into was the unavailability of 5.6mA constant current diodes, so I'll be using two smaller ones in parallel to acheive the same current. I'll put up a nice excel spreadsheet with every single item I've ordered from each source with prices and parts numbers this weekend. I'd say this part took me about two or three hours - it probably wouldn't take that long for someone with any DIY audio experience - without it, probably something like that much. I'll be happy to answer any questions anyone has about the parts ordering/selection process, just drop a post or PM.

 Jimmy.


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_One problem I ran into was the unavailability of 5.6mA constant current diodes._

 

Jimmy,

 My Rapid order was short of two RCA sockets (out of stock) so I'll be reordering them in a couple of days....... I can get you a couple of CRD's when I'm at it if you like?

CCD

 Mike.


----------



## Alick

Quote:


 In the meantime, is there anyone who has built a standard WNA who would be willing to assure "X" that he'll get a lot more performance from a WNA than a commercially built amp costing 4 times the price? 
 

Glad to see this thread still going and glad to contribute some reassurance for "X". My WNA is a pretty standard implementation of the class 'A' biased LM6171 version in the larger enclosure that Mike used with his second build.

 The sound quality vs. my Mullard rolled X-Can V2 is incomparable. The WNA trounces it. The sound's fast and detailed and the sound-stage is very convincing. I listen to a lot of acoustic stuff and find that instruments sound more realistic, individual instruments are more identifiable and there is stuff I've never heard before on discs I thought I knew well. Above all (perhaps despite all this) the amp is very musical and extremely enjoyable to listen to. It sounds good from the off, but improves with age and burn-in long.

 As for the DIY process, it's relatively easy for us Brits. You can order an (almost) complete kit form David White or just by the PCB from David and use Mikes parts list to order the rest from Maplin and Rapid. I followed the latter route and received deliveries from all three a day later. There are a couple of minor quantity errors on Mikes list (10R resistors and one of the diodes ISTR; can you remember Mike?) The enclosure recommended by Mike is easy to drill (the front and back panels are plastic) and there's plenty of room to work inside. Be careful when soldering after the panels are populated as they look easy to melt.

 Populating the PCB took a couple of hours (over a few days as I needed 'emergency supplies' from Mike on two or three occasions) but it was the first PCB I'd populated for a few years so I took my time. Hooking up the PCB to the enclosure and controls took around half an hour and up to another half an hour to check and recheck the polarity of the power connector before plucking up the courage to power up. This will vary depending on your levels of confidence and paranoia.

 Overall it was a fun project, the service from Rapid, Maplin and (especially) David White superb and the support from Mike invaluable. Above all, the result is an amplifier which performs at a level miles above its cost.


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_Jimmy,

 My Rapid order was short of two RCA sockets (out of stock) so I'll be reordering them in a couple of days....... I can get you a couple of CRD's when I'm at it if you like?

CCD

 Mike._

 

Nah, it's alright. I found a pair to put in parallel that'll be fine and I'll just clip the leads on one short and solder them to the leads of the other just outside the case, so that the one with clipped leads sits right on top of the other and doesn't increase the footprint. They may have to sit slightly off of the board, but not enough to cause problems. Thanks for the offer, though, Mike.

 Jimmy.


----------



## PinkFloyd

The PCB hasn't arrived yet but all the other bits and bobs are here so I've fitted the case out.... certainly does look very good in the all aluminium enclosure.

 I managed to source an absolutely superb little PSU which I have tried with the gspaudio Solo amp and it's almost as good as the gspaudio PSU1... I'm very surprised by this little PSU 
	

	
	
		
		

		
		
	


	








 enclosure for WNA, obviously pot shaft is still waiting to be trimmed. 





 Front panel with on / off switch, headphone socket, volume control and chrome LED bezel.





 Rear of enclosure with BNC power socket and gold plated RCA sockets





 Compact and bijout PSU..... sounds great


----------



## Alick

I really like the gold-plated BNC power connector. The aluminium panels aren't too shabby either. OK, where's the PSU from?


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I really like the gold-plated BNC power connector. The aluminium panels aren't too shabby either. OK, where's the PSU from?_

 


 Hi Alick,

 It doesn't come with the gold plated BNC connector as standard, I fitted that myself. It's a Rapid PSU and very very good considering the size.... I've got it on test powering the gspaudio Solo and there is no shame to this little beauty it's a little cracker.

 Compared to the electrical deathtrap I have been powering my amps with for a while it's great using this with no fear of getting electrocuted 
	

	
	
		
		

		
			





 I really must get round to casing that PSU up lol.





 Rapid PSU pictured alonside potential deathtrap 
	

	
	
		
		

		
		
	


	








 Rapid PSU powering a very strange looking gspaudio Solo


----------



## Alick

Cheers Mike. I like the idea of using the BNC, but it's worth reminding others that you really have to make sure that the outer isn't connected to ground in any way as the amp needs a floating supply. 

 Do you think the new Rapid PSU is a significant improvement over the originally recommended one?


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Cheers Mike. I like the idea of using the BNC, but it's worth reminding others that you really have to make sure that the outer isn't connected to ground in any way as the amp needs a floating supply. 

 Do you think the new Rapid PSU is a significant improvement over the originally recommended one?_

 

It's sounds much about the same to be honest and about the same as my fancy uncased death trap PSU... there's not a lot in it and if I were to say that there was a tremedous improvement in sound between them I'd be lying. Put it this way, If I could get a refund on death trap PSU I'd happily live with the Rapid PSU.

 By the time I case the death trap up the exercise will have cost me quite a lot of money for a PSU and I'd probably get the same sound from an off the shelf Rapid job..... oh well.


----------



## PinkFloyd

Got up nice and early this morning thanks to the postman ringing the doorbell with the WNA PCB, I normally don't get up early on a Saturday morning but when there's a PCB at the door I don't mind 
	

	
	
		
		

		
		
	


	




 I've spent a very enjoyable day armed with a soldering iron and I'm pleased to report that she lives and is sounding out of this world 
	

	
	
		
		

		
		
	


	









 Pretty much the same parts list as the last one (ALPS RK27, 0.1% 15ppm metal fim resistors etc. etc) apart from the addition of two 220uF ELNA cerafine coupling caps and non polar output caps.... oh, and a BNC socket for the power in. I've fitted LM6171's throughout.

 It's on test at the moment and sounding wonderfully fast, detailed and three dimensional.... the little stontronics PSU is performing great though I will connect up the Calex open frame PSU for a good listen later on to see if there is any improvement or not.


----------



## Alick

That aluminium panel looks really good with the aluminium knob. Is this your third or fourth build Mike? I must get round to trying a LM6171 in the power splitter location; it's a drop in replacement, isn't it?

  Quote:


 I normally don't get up early on a Saturday morning but when there's a PCB at the door I don't mind 
 

I'm finding the WNA is robbing me of sleep at the other end of Saturday. I generally have a listening session with a (few) glass(es) of whisky on a Saturday night after SO goes to bed. Since I replaced the X-Can V2 with the WNA, I find I'm listening to more, later...


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_That aluminium panel looks really good with the aluminium knob. Is this your third or fourth build Mike? I must get round to trying a LM6171 in the power splitter location; it's a drop in replacement, isn't it?
_

 

Hi Alick,

 First off I think this power supply stuff is a crock of crap.... they all sound the same to me....... I was expecting an eargasm from the Calex but the amp sounded identical whatever the PSU so PSU's go into room 101 
	

	
	
		
		

		
		
	


	




 This is my fourth build, yes, so I should be getting good at it by now 
	

	
	
		
		

		
		
	


	




 LM6171 is a direct drop in in the rail splitter section....... yes. Sounds a lot better "even faster" with it in the circuit and I believe synergy has a lot to with it....... LM's across the board instead of 2 LM's and a BB 
	

	
	
		
		

		
		
	


	




 I mean you wouldn't mix and match tyres on your car so why mix different brands in the amp 

 All the best.

 Mike.


----------



## jpmoon

After convincing myself that I had constructed my wna amp correctly, I stopped fiddling with it and actually listened to some music. Initially, I was a bit concerned that all I would be hearing would be the limitations of my sources, bags of tape hiss and loads of vinyl surface noise, etc. (Aside from any limitations in taste). All of these are reproduced, but they don't seem to detract from the sheer listening pleasure.

 As a newcomer to quality headphone listening, I can't make any meaningful quality comparisons with other amps, but I'm glad I plucked up the courage to buy some cans and do some soldering. I think I've used up my quota of listening time in the last fortnight.

 On the PSU debate, for small time intervals the decoupling capacitors ARE the PSU - isn't that the theory? Anything competent to charge the decoupling capacitors should work. I'm probably being smug - I'm sticking with the plug top PSU for bangs per buck reasons. This little project has already spawned several sub-projects, so I'm saving my pennys.

 Best wishes, John.


----------



## PinkFloyd

Quote:


  Originally Posted by *jpmoon* 
_ Initially, I was a bit concerned that all I would be hearing would be the limitations of my sources, bags of tape hiss and loads of vinyl surface noise, etc. (Aside from any limitations in taste). All of these are reproduced, but they don't seem to detract from the sheer listening pleasure.
_

 

I should hope the hiss and crackles "are" amplified John...... if they weren't you'd have one extremely weird amp ..... the amp will only amplify what it's fed, it won't smooth over the cracks and pops and it won't make a silk purse out of a pigs ear...... it will amplify the signal (music) , warts and all


----------



## PinkFloyd

Quote:


  Originally Posted by *PinkFloyd* 
_
 First off I think this power supply stuff is a crock of crap.... they all sound the same to me......._

 

I couldn't believe I came out and said that and felt I had to prove myself wrong.... maybe the "deathtrap" didn't sound good because it didn't look good? 

 Well, I housed the deathtrap (open frame, risk of instant death if you make contact with certain parts) in a nice transluscent enclosure earlier on and fitted a fancy purple LED and it looks a million dollars in real life (the pics don't do it any justice)

 It's a Calex 24V DC linear regualted PSU with LM723 regulator and ST Microelectronics 2N3055 transistor so this is technically one mother of a PSU and should (if what we are led to believe holds true) make the music sound sooooo much better. 

 Well........... it doesn't. I can't differentiate between a £7 stontronics regulated wart , a £11.50 Stontronics desktop switcher or a £50 Calex open frame linear regulated PSU....... I know I haven't gone deaf so can only assume that this amp sounds awesome with any PSU which outputs 24V DC.

 I'm contemplating illuminating the innards of the Calex with either LED's or a neon tube....... it may not be "hi-fi" but it sure will look good 
	

	
	
		
		

		
		
	


	



















 It looks so much better in real life and it's a lot safer...... bye bye deathtrap and hello blue plastic thingy with purple LED


----------



## StevieDvd

Glad to hear the desktop I ordered will be OK then!

 PS is that style your new look or is it to fit in with the kitchen tiles 
	

	
	
		
		

		
		
	


	




 Sorry I'm in a playful mood tonight.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_PS is that style your new look or is it to fit in with the kitchen tiles 
	

	
	
		
		

		
		
	


	



_

 

Neither Steve, I thought of you when I chose to build into a translucent blue enclosure


----------



## jnewman

All my parts are in the mail and on the way now (minus the enclosure, which I forgot to order from lansing-enclosures.com today and will order tomorrow), so hopefully I'll be able to get started in about a week. We'll see when they get here. I've also got one of the Hakko 936 clones on the way, and I've just found out I have access to a complete (including CNC) machine shop, so I should have all the tools I need. Maybe. 
	

	
	
		
		

		
		
	


	




. More update as things start arriving.

 Jimmy


----------



## flecom

have you looked at the LM7171, according to national it has "improved bandwidth, slew rate, input bias current and output current."


----------



## jnewman

Quote:


  Originally Posted by *flecom* 
_have you looked at the LM7171, according to national it has "improved bandwidth, slew rate, input bias current and output current."_

 

Doesn't the LM6171 already have a higher slew rate and more bandwidth than most of the opamps used in audio applications?


----------



## PinkFloyd

Quote:


  Originally Posted by *flecom* 
_have you looked at the LM7171, according to national it has "improved bandwidth, slew rate, input bias current and output current."_

 

LM7171 looks great with a slew rate of 4100 !!

 Temperature Min (deg C) -40, -55 
 Temperature Max (deg C) 85, 125 
 Channels (Channels) 1 
 Input OutputType Not Rail to Rail 
 Gain Bandwidth (MHz) 200 
 Slew Rate (Volts/usec) 4100 
 SupplyCurrent Per Channel (mA) 6.50 
 Supply Min (Volt) 5.50 
 Supply Max (Volt) 36 
 Offset Voltage (mV) 1, 3 
 Max Input Bias Current (nA) 12000 
 Output Current (mA) 100 
 Voltage Noise (nV/Hz) 14 
 Shut down No


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Alick,

 First off I think this power supply stuff is a crock of crap.... they all sound the same to me....... I was expecting an eargasm from the Calex but the amp sounded identical whatever the PSU so PSU's go into room 101 
	

	
	
		
		

		
			





 Mike._

 

The Rapid desktop PSU came yesterday and works fine. I cannot discern difference between the plugtop and desktop apart from the weight and sizes.

 Good spot, thanks.


----------



## jnewman

Well, it looks like most of my stuff won't be getting here until early/mid next week, which is a shame because I'm going to be very, very busy. I'd at least be able to get started with the stuff that's getting here this week except that I decided very specifically to use ONLY Cardas Quadeutectic solder in all my DIY projects, and that's in what will probably the the last package to get here. I love how that works out. Oh well, can't have everything, I guess.

 Jimmy


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_The Rapid desktop PSU came yesterday and works fine. I cannot discern difference between the plugtop and desktop apart from the weight and sizes.

 Good spot, thanks._

 

It sure is a nifty little thing isn't it? Excellent for the money and not at all bad sounding....... the Calex is actually not too bad now it's cased up there seems to be a degree more "oomph" to the sound but certainly not an _enormous_ difference over the wallwart.


----------



## StevieDvd

If SWMBO gives me a chance I'll be trying to review a new setup this weekend.

 CD is a NAD 521BEE feeding to a Non-Sampling DAC in turn fed through the WNA to my HD650s.

 Second check will be PC via USB soundcard DigitalOut via DAC and again the WNA>HD650.

 Got to make up some fresh interconnects instead of the overly long ones used for tests.

 See DAC details http://cgi.ebay.co.uk/ws/eBayISAPI.d...e=STRK:MEWN:IT


----------



## Bassivus

Hi everybody,

 Since this is my first post I feel like I should say a few things about me, just to introduce myself. I’m a professional musician and I have NO, or very little knowledge in electronics. I have some experience in DIY making my speakers and tweaking CD, a lot of will to learn more, but otherwise I’m a NEWBIE and a DUMMY. 
 Now back to topics. After couple of months of searching for headamp project, I decided to go for WNA, thanks to this thread. I have just placed an order with WNA for audiophile headphone amp pcb without the plug top power supply, without resistors, and with the opa627s replaced with LM6171s. I was wondering would it be a bad idea to put PSU in same case with amp? And what do you think about this:

 High quality power supplies with stabilised output designed for easy installation onto standard symmetrical 35mm DIN-rail (DIN EN 50 022).
 Additional screw fixings are provided to secure the GLS 24-5. Suitable for a wide range of industrial control applications. 


 230Va.c input 24V d.c stablised output

 Safety isolating transformer to VDE 0551, EN 60742

 4 kV input/output flash tested

 Finger safe easy accessible screw terminals

 Double screw terminals on the output

 Input and output fuse protection

 LED output voltage indicator


 technical specification 

 type Iout (A) Pout (W) 
 GLS 230/24-0.5 0.5 12 



 Output voltage 24V d.c nom. stablised 
 Input voltage 230Va.c + 6% -10% 
 Input frequency 50 to 60Hz 
 Load regulation ±1% 
 Ripple factor £30mV pk-pk 
 Operating temperature range 0 to 60°C 
 (derate above +40°C )


----------



## jnewman

Bassivus:

 There are three things you need to know if you're using an internal power supply:

 1. An internal power supply brings 230V AC into the amp case, which generates electromagnetic fields and may caus hum.
 2. An internal power supply makes the inside of the case warmer (shouldn't be much of an issue).
 3. This is the MOST IMPORTANT - it means you have wall current going into your amp - if you're not very careful and you don't ground/isolate everything correctly, it's not very hard to electrocute yourself.

 Also, most internal power supplies will take up more space in an enclosure than the amp itself, so you'd need to get a much larger enclosure than usual.


----------



## jnewman

PinkFloyd or anyone else who wants to answer:

 What do you think of modding the PS section a la PPA by increasing the C3/C5 capacitance (maybe by a pretty fair amount) and possibly switching to two bypass caps with different values (PPA standard is 1uF and .01uF, WNA standard is .1uF)?


----------



## bart

Hi Pink

  Quote:


 Originally posted by *PinkFloyd* 

_bye bye deathtrap and hello blue plastic thingy with purple LED_ 
 

Your new blue PSU plastic thingy looks GREAT. As in: I want one! I want one!

 What's the specs on it? 

 Also how's the heat? Does keep cool enough or did you cut some ventilation holes ?

 /Bart


----------



## jnewman

And also, looking around more, I have 10uF bipolar output caps, which Dr. White's notes say should be fine - but I see people suggesting 100uF or more for output caps - would something larger be better?


----------



## PinkFloyd

Quote:


  Originally Posted by *bart* 
_
 Your new blue PSU plastic thingy looks GREAT. As in: I want one! I want one!

 What's the specs on it? 

 Also how's the heat? Does keep cool enough or did you cut some ventilation holes ?

 /Bart_

 

Hi Bart,

 It runs as cool as a cucumber and the aluminium frame it is mounted on is more than enough to dissipate heat.

 The specs are:

 GENERAL SPECIFICATIONS
*A.C. Input * 100/120/220/240VAC +10%, -12%,
 47 to 440Hz
*D.C. Output * See Voltage/Current Rating Chart. Adjustment range
 ±5% minimum.
*Line Regulation * ±0.05% for a 10% line change.
*Load Regulation * ±0.05% for a 50% load change.
*Output Ripple * 2V to 15V units: 5.0mV PK-PK maximum
 20V to 28V units: 0.02% PK-PK maximum
*Transient Response * 50µseconds for a 50% load change
*Short Circuit and
 Overload Protection * Automatic current limit/foldback
*Overvoltage Protection * Built-in on all 5V outputs. Set at 6.2V ±0.4V Other models
 use optional overvoltage protection.
 See Option 4 overleaf
 Remote Sensing Provided on most models,
 open sense load protection built in.
*Stability* ±0.3% for 24 hour period after 1 hour warm-up
*Temperature Rating * Standard Range: 0°C to +50°C full-rated,
*derated linearly * to 40% at 70°C
*Extended Range:* -40°C to +50°C full-rated,
*derated linearly * to 40% at 70°C
 TEMPERATURE DERATING CURVE
*Temperature Coefficient * ±0.03%/°C maximum
*Efficienc*y (typical) 5V unit: 45%; 12V and 15V units: 55%; 24V units: 60%
*Vibration* Per MIL-STD-810C, Method 514, Procedure X
*Shock* Per MIL-STD-810C, Method 516, Procedure V
*Isolation Input to ground*: 3750VAC min.



 The psu is British designed and manufactured in the UK..... it has an ST Microelectronics 2N3055 transistor and LM723 regulator

 Part number 32024A 24V - 28V output 1.2 amps

http://www.calex.co.uk/OpenFrameRegLinearPSUs.pdf


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_What do you think of modding the PS section a la PPA by increasing the C3/C5 capacitance (maybe by a pretty fair amount) and possibly switching to two bypass caps with different values (PPA standard is 1uF and .01uF, WNA standard is .1uF)?_

 

Should be fine Jimmy but probably best to e-mail David with this question he'll be able to give you a definitive answer as his knowledge of the circuit is second to none considering he designed it 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *jnewman* 
_And also, looking around more, I have 10uF bipolar output caps, which Dr. White's notes say should be fine - but I see people suggesting 100uF or more for output caps - would something larger be better?_

 

Anything over 4u7 will do the job....... I tried 4u7, 12uF and 25uF... the bass seemed to go down lower with cap values above 4u7..... 10uF should be fine but if you can fit 100uF's into the enclosure then go for it


----------



## jnewman

Quote from Dr. White:

 It certainly won't do any harm to increase the power rail decouplers from 100uF up to 1000uF. As to sonic benefits I can't say because I haven't tried increasing the values and doing a listening test. My guess is that any improvement will be small, but maybe worthwhile. You could try asking Pink Floyd because I'm pretty sure that he used 220uF instead of 100uF on the last WNA headphone amp he built. I normally use 22uF 50V non polars by themselves on the output. A working voltage of 25V and up will be ok - I used 50V because you often can't get low working voltages with small non polars. The impedance of these will increase at high frequencies so you might get some sonic benefit if you bypass them with a film cap of around 1uF. If you have really low impedance ( 8-64R ) headphones it might be an idea to increase the output caps to around 100 - 220uF.

 Having read that, I'm going to grab some 1000uF blackgates to put in parallel with the 100's in the power supply (or possibly replace them - I'll try both configurations). I'm also going to get some 100uF (maybe 220uF's if they're available - they're not in the catalog at partsconnexion) bipolar bg's and some Solen Polyprop film/foil 1uF's to put in series with the big caps and 10uF's. I don't have a lot of experience with this, so it'll give me an easy way to try a number of different configurations in an amp I know and see how they sound.

 Jimmy


----------



## Bassivus

Jnewman:

 I guess you are right… to many issues 
	

	
	
		
		

		
		
	


	




 , 
  Quote:


  Originally Posted by *jnewman* 
_
 There are three things you need to know if you're using an internal power supply:

 1. An internal power supply brings 230V AC into the amp case, which generates electromagnetic fields and may caus hum.
 2. An internal power supply makes the inside of the case warmer (shouldn't be much of an issue).
 3. This is the MOST IMPORTANT - it means you have wall current going into your amp - if you're not very careful and you don't ground/isolate everything correctly, it's not very hard to electrocute yourself.

 Also, most internal power supplies will take up more space in an enclosure than the amp itself, so you'd need to get a much larger enclosure than usual._

 

So I’ll stick with separate amp - PSU design. 
	

	
	
		
		

		
		
	


	



 I found this as *Power-One* a cheaper alternative to PinkFloyds *Calex*, so I would like to hear the comments from you guys. It is a 0.5A which Is as I understand sufficient, and if not next up is 1.2A like Calex

*Power-One HA24-0.5-A*, 

 Farnel number: 5059630 

 Specs are:
 [size=xx-small]
 Worldwide AC Input Capabilities:
 100/120/220/230/240 VAC
 • ±0.05% Output Regulation
 • Low Output Ripple
 • Mean Time Before Failure (MTBF) in Excess of
 300,000 Hours
 • 100% Burn-In

 Input Specifications
 PARAMETER CONDITIONS/DESCRIPTION MIN NOM MAX UNITS
 Input Voltage - AC Jumper selectable, shipped factory configured for 100 VAC Tap 87 100 110
 (Note 1, 2) 120VAC operation. All models must be externally 120 VAC Tap 104 120 132
 VAC fused for proper operation. Fuse ratings are marked 220 VAC Tap 191 220 242
 on each unit. Consult factory for each unit’s fuse 240 VAC Tap 209 240 264
 requirements.
 Input Frequency AC input. 47 63 Hz
 Line Regulation Output voltage charge for a 10% line change: F case models. -0.01 +0.01
 HAD12, HAD15. -1.0 +1.0% Outputs with adjustable three terminal regulators. -0.5 +0.5
 All other models. -0.05 +0.05
 NOTES: 1) Derate output current 10% for 50Hz operation.
 2) Input voltage tolerance for 230VAC operation is +15%, -10%.

 Output Specifications
 PARAMETER CONDITIONS/DESCRIPTION MIN NOM MAX UNITS
 Output Adjustment Minimum output adjustment range (Note 1). -5 +5 %
 Efficiency 5 volt outputs. 45
 12 volt and 15 volt outputs. 55 %
 24 volt and higher outputs. 60
 24 volt through 250 volt models. 3.0mVPK-PK plus 0.02% of output voltage, max
 Load Regulation Output change for a 50% load change: F case models. -0.02 +0.02
 HAD12, HAD15. -1 +1% Outputs with adjustable three terminal regulators. -0.5 +0.5
 All other models. -0.05 +0.05
 Transient Response Recovery time, to within 1% of initial set point due to a 50% load change. 50 µs[/size]


----------



## jnewman

If those specs are anywhere near correct, that PSU'd be fine. The (more or less) default low-to-mid range psu for the PPA is an Elpac wallwart that only has 1% output regulation. The one you've posted is well into true linear open frame large transformer PSU territory.

  Quote:


  Originally Posted by *Bassivus* 
_Jnewman:

 I guess you are right… to many issues 
	

	
	
		
		

		
		
	


	




 , 

 So I’ll stick with separate amp - PSU design. 
	

	
	
		
		

		
		
	


	



 I found this as *Power-One* a cheaper alternative to PinkFloyds *Calex*, so I would like to hear the comments from you guys. It is a 0.5A which Is as I understand sufficient, and if not next up is 1.2A like Calex

*Power-One HA24-0.5-A*, 

 Farnel number: 5059630 

 Specs are:
 [size=xx-small]
 Worldwide AC Input Capabilities:
 100/120/220/230/240 VAC
 • ±0.05% Output Regulation
 • Low Output Ripple
 • Mean Time Before Failure (MTBF) in Excess of
 300,000 Hours
 • 100% Burn-In

 Input Specifications
 PARAMETER CONDITIONS/DESCRIPTION MIN NOM MAX UNITS
 Input Voltage - AC Jumper selectable, shipped factory configured for 100 VAC Tap 87 100 110
 (Note 1, 2) 120VAC operation. All models must be externally 120 VAC Tap 104 120 132
 VAC fused for proper operation. Fuse ratings are marked 220 VAC Tap 191 220 242
 on each unit. Consult factory for each unit’s fuse 240 VAC Tap 209 240 264
 requirements.
 Input Frequency AC input. 47 63 Hz
 Line Regulation Output voltage charge for a 10% line change: F case models. -0.01 +0.01
 HAD12, HAD15. -1.0 +1.0% Outputs with adjustable three terminal regulators. -0.5 +0.5
 All other models. -0.05 +0.05
 NOTES: 1) Derate output current 10% for 50Hz operation.
 2) Input voltage tolerance for 230VAC operation is +15%, -10%.

 Output Specifications
 PARAMETER CONDITIONS/DESCRIPTION MIN NOM MAX UNITS
 Output Adjustment Minimum output adjustment range (Note 1). -5 +5 %
 Efficiency 5 volt outputs. 45
 12 volt and 15 volt outputs. 55 %
 24 volt and higher outputs. 60
 24 volt through 250 volt models. 3.0mVPK-PK plus 0.02% of output voltage, max
 Load Regulation Output change for a 50% load change: F case models. -0.02 +0.02
 HAD12, HAD15. -1 +1% Outputs with adjustable three terminal regulators. -0.5 +0.5
 All other models. -0.05 +0.05
 Transient Response Recovery time, to within 1% of initial set point due to a 50% load change. 50 µs[/size]_


----------



## bart

Quote:


  Originally Posted by *PinkFloyd* 
_
 It runs as cool as a cucumber and the aluminium frame it is mounted on is more than enough to dissipate heat.

 The specs are:_

 

Mucho thnx for the info. I'm in Canada but definitely looks worth the shipping cost!


----------



## jnewman

Well, I've got my WNA working (and MOSTLY put together). I don't have the panel work done yet because I'm doing it in a machine shop later this week or early next week, but I've got it running and it sounds really great. I did manage to waste about four hours though - I had it put together and running fine and sounding great. Then I added the volume pot and some extra wires to make it easier to hook things up. Between messed up cables and a non-working pot (yes, I had both a defunct panasonic EVJ and a test cable that's broken), it took me FOREVER to get things working again - but now it is and it sounds excellent. It _really_ does sound good. 

 Anyway. I think I'm going to try to find a blue velvet somewhere to pop in - there aren't many places that have them in stock though. 

 I'll put some pictures up once I've got the case together and get a pot for it - if anyone has a recommendation for something other than a blue velvet or an EVJ, something new's always nice to try. I'll also put up more impressions once I have some more listening time with it.


----------



## PinkFloyd

Hi Jimmy,

 Great to hear you've finally got her up and running  A pot I would highly recommend is the Vishay PA-11 a very good pot and a very good size too..... they are pretty expensive over here in the UK but may be a bit cheaper over in the US.

 What output caps did you decide to go with?

 All the best.

 Mike.


----------



## StevieDvd

Mike,

 Quickie question re the WNA.

 I had connected a new DCA in between the WNA and my Nad CD player and noticed that when I was touching the volume control on the WNA I got a little hum. I checked and when I touch the volume control I do a slight buzz. Is it possible I'm grounding something or do I need to ground something to resolve this?

 My simple idea was to insulate the volume control stem at first but thought you may know a better way.

 Steve


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Jimmy,

 Great to hear you've finally got her up and running  A pot I would highly recommend is the Vishay PA-11 a very good pot and a very good size too..... they are pretty expensive over here in the UK but may be a bit cheaper over in the US.

 What output caps did you decide to go with?

 All the best.

 Mike._

 

I've just put in the 10uF blackgate N's that I had originally - I'm going to let it play for a while and get used to the sound, and eventually I'll try out something bigger 
	

	
	
		
		

		
			





.

 It sounds about a thousand times better than my MINT, so I'm pretty happy - heh.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Mike,

 Quickie question re the WNA.

 I had connected a new DCA in between the WNA and my Nad CD player and noticed that when I was touching the volume control on the WNA I got a little hum. I checked and when I touch the volume control I do a slight buzz. Is it possible I'm grounding something or do I need to ground something to resolve this?

 My simple idea was to insulate the volume control stem at first but thought you may know a better way.

 Steve_

 


 Run a wire from the chassis (or ground on the board) to the casing of the pot (isn't that in the instructions?) EDIT: I built the amp so I shouldn't be asking you.......... run a wire from the chassis to the housing of the pot, I'll PM you with directions.......... SECOND EDIT: by "buzz" do you mean a slight electric shock?


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Run a wire from the chassis (or ground on the board) to the casing of the pot (isn't that in the instructions?) EDIT: I built the amp so I shouldn't be asking you.......... run a wire from the chassis to the housing of the pot, I'll PM you with directions.......... SECOND EDIT: by "buzz" do you mean a slight electric shock?_

 

Sorry was a bit pushed for time yesterday due to my daughter having her mobile phone stolen.

 The buzz or should I say hum is an audible one. I was adjusting the volume in between tracks and as I turned up the volume I noticed the hum, it goes as soon as you stop touching the pot. Also get a hum when touching the case though not as loud.

 I will try the same again without the DAC in series to see if that is introducing it. It's not a big deal but if the solution was simple I'd obviously remedy it.

 Will also try to knock up a switch so I can compare the sound from CD > WNA versus CD > DAC > WNA, my main trouble is that everything sounds so good it's hard to compare. By the time the wires have all been switched over how does one remember what the earlier sound was like!

 PS how's your teeth?


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_ PS how's your teeth?_

 

Still playing up, I've got a 60 minute appointment with the dentist next Monday.... he's definitely removing one tooth and will assess the situation once he "goes in" to see if the one next to it needs removing also. If it _does_ require removing then bang goes the 8 tooth bridge 
	

	
	
		
		

		
		
	


	




 It'll mean that it will have to be removed along with a further 2 good teeth so it's possible that 4 teeth will be extracted and I will return home with only 5 teeth remaining in the top of my mouth.... 3 at the back on the LH side and 2 at the back on the RH side... so at least I will still be able to crunch pork scratchings


----------



## PinkFloyd

Hi Steve,

 David has been reading this thread and this may help you with your hum:

 "I read that post last night. I think he means that he hears a buzz in the headphones when he touches the volco - you can't get a shock from 24V and its extremely unlikely that a power supply would "go live" at all, far less doing so and still be working. Nah this is the classic symptom of an unearthed case.Is the case metal or plastic? If its plastic then line it with metal foil ( stick the foil to the plastic ) and connect the foil to the headamp Gnd. If metal, then the Gnd line of the amp should be connected to the case somehow - easiest way to do this is to make sure that one ( and only one ) of the phono inputs is bolted directly to the chassis without insulation. I recognise the symptoms because this happened to me with the first ( metal ) cased headamp I built for a customer."



 All the best

 Mike.


----------



## PinkFloyd

David is now offering a full kit with PSU for £150 which is a _very_ decent price 
	

	
	
		
		

		
		
	


	




 It includes everything you need and comes with a 135 x 105x 40mm hard black anodised aluminium case with Alps volume control, 6.35mm gold plated headphone jack, 3 x LM6171, and all the class A mods for £150 + shipping. The power supply is normally a 24V regulated linear plugtop for Europe and a 24V switcher for the US. European customers can have the switcher if they ask for it.


----------



## goodychrischild

Pink Floyd,

 Do you know what capacitors he is including (After the splitter and output) with the full LM6171 kit as this seems a bit of a grey area to me at the moment.

 I'm currently putting together the orders for all the bits and this is the area causing the most deliberation 
	

	
	
		
		

		
		
	


	




 Chris


----------



## Alick

Quote:


 David is now offering a full kit with PSU for £150 which is a very decent price 
 

That _is_ a good price. Is the case pre-drilled? I'd have probably bought that kit had it been available. C'est la vie...


----------



## Bassivus

Quote:


  Originally Posted by *PinkFloyd* 
_David is now offering a full kit with PSU for £150 which is a very decent price 
	

	
	
		
		

		
		
	


	




 It includes everything you need and comes with a 135 x 105x 40mm hard black anodised aluminium case with Alps volume control, 6.35mm gold plated headphone jack, 3 x LM6171, and all the class A mods for £150 + shipping. The power supply is normally a 24V regulated linear plugtop for Europe and a 24V switcher for the US. European customers can have the switcher if they ask for it._

 

I too did not know for the complete LM6171 kit with case and all, since I would also go for it…
	

	
	
		
		

		
		
	


	



 Instead, some 10 days ago I have ordered audiophile kit from WNA asking David to leave out the 1.Resistors 2.Plugtop PSU 3. LM6171 x 3 instead of OP627 not asking for anything else changed. I just got the package and I guess that David (correctly) assumed that I’m going for A class mod and sent me the kit including both CCDs required for mod, jumpers for leaving out R4; NITAI non polar 22uF/63V as output caps, and OS CONS but 47uF/20V!!! I believe that he did not just forgot to change those for my kit!?!?!


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Steve,

 David has been reading this thread and this may help you with your hum:

 "I read that post last night. I think he means that he hears a buzz in the headphones when he touches the volco - you can't get a shock from 24V and its extremely unlikely that a power supply would "go live" at all, far less doing so and still be working. Nah this is the classic symptom of an unearthed case.Is the case metal or plastic? If its plastic then line it with metal foil ( stick the foil to the plastic ) and connect the foil to the headamp Gnd. If metal, then the Gnd line of the amp should be connected to the case somehow - easiest way to do this is to make sure that one ( and only one ) of the phono inputs is bolted directly to the chassis without insulation. I recognise the symptoms because this happened to me with the first ( metal ) cased headamp I built for a customer."


 All the best

 Mike._

 


 Wunderbar,

 If I get home before midnight tonight I'll give that a try. Thanks Mike and David keep up the good work and long live WNA!

 Steve


----------



## PinkFloyd

I can confirm that the *£150 * kit David supplies comes with a predrilled enclosure and everything required to build the complete amp.

 It really is an absolutely _superb_ price for a kit that offers such a _very_ high quality sound.... You will be hard pushed to source the components yourself for that money. You'd also be very hard pushed to find a commercial amp that sounds anywhere near as good as the WNA for 4 - 5 times the price of the kit.

 I've asked David to outline the key parts of the kit and here they are:

 the *£150 * + shipping kit comes with a predrilled/punched hard black anodized aluminium case 135x105x40mm, the opamps are all LM6171s, the resistors are Welwyn RC55Ys, the volume control is an Alps, the 100nF caps are polypropylenes, the 100uF decouplers are Rubycon ZAs, the ouput caps are Nitai non polarised, all parts included for class A biasing mods, there is a single pair of gold plated phono inputs, a gold plated 6.35mm headphone jack output, blue led power indicator, black anodised 38mm volco knob, standard 2.1mm power input jack, 24V plugtop psu either linear or switcher.


----------



## PinkFloyd

Quote:


  Originally Posted by *Bassivus* 
_ and OS CONS but 47uF/20V!!! I believe that he did not just forgot to change those for my kit!?!?!_

 

The 47uF / 20V OSCONS are not a mistake Bassivus....... Sanyo reckon that you can use an OSCON one fifth the value of an ordinary electrolytic in the same position. So 100uF( usual value)/5 = 22uF( nearest value ). Factor of two safety margin, 22x2=47uF( nearest value )...... no problems there.


----------



## Bassivus

Quote:


  Originally Posted by *PinkFloyd* 
_The 47uF / 20V OSCONS are not a mistake Bassivus....... Sanyo reckon that you can use an OSCON one fifth the value of an ordinary electrolytic in the same position. So 100uF( usual value)/5 = 22uF( nearest value ). Factor of two safety margin, 22x2=47uF( nearest value )...... no problems there._

 

Ok I think I get it, thanx for the explanation Pink, but what about your warning about LM6171+OSCON=oscilation ?


----------



## StevieDvd

Quote:


  Originally Posted by *StevieDvd* 
_Wunderbar,

 If I get home before midnight tonight I'll give that a try. Thanks Mike and David keep up the good work and long live WNA!

 Steve_

 


 Pinkie,

 The buzz is not cured by a connecting he case to the ground of an RCA, but I did notice it was cured when I touched the volume control and the metal ring of the power jack socket. Does that give a clue as to the cause?


----------



## jnewman

I continue to be EXTREMELY impressed with this amplifier.
 I'm using it with my K501's (why do you say you don't think they go well together, Mike?), and it's amazing - velvety, clear, and more soundstage than I've ever heard before (arguably, I don't have a lot of experience with high-end amps, just CMOY's and a top-quality MINT). Running nonstop for the past two days has made things smooth out and clear up a lot - I hope it keeps going like this for another two or three days 
	

	
	
		
		

		
		
	


	




.

 Oh, and there's a blue velvet on the way - couldn't find a US supplier of the PA11.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Pinkie,

 The buzz is not cured by a connecting he case to the ground of an RCA, but I did notice it was cured when I touched the volume control and the metal ring of the power jack socket. Does that give a clue as to the cause?_

 

Steve,

 You wouldn't happen to have replaced the ABS faceplates with aluminium ones by any chance? if so then make sure the phono sockets and DC socket are insulated from the chassis.

 This has only manifested itself after the addition of a new component in the signal path and all was ok before?

 Online diagnosis is HARD... I threw this problem over to David and:

 "Mike,
 Hmm. Its still an earthing problem but more obscure. If the case is metal and the volco is an Alps with a metal spindle I would have thought this would be at case potential. In that instance even touching the case should cause hum. I take it that the power jack is of the insulated variety, ie the sleeve connection is isolated from the mounting of the chassis power plug?


 Regards, David"


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Pinkie,

 The buzz is not cured by a connecting he case to the ground of an RCA, but I did notice it was cured when I touched the volume control and the metal ring of the power jack socket. Does that give a clue as to the cause?_

 

If you look further up 
	

	
	
		
		

		
		
	


	




 you'll see that I originally suggested "Run a wire from the chassis (or ground on the board) to the casing of the pot (isn't that in the instructions?) EDIT: I built the amp so I shouldn't be asking you.......... run a wire from the chassis to the housing of the pot"

 Did you try that???


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_If you look further up 
	

	
	
		
		

		
		
	


	




 you'll see that I originally suggested "Run a wire from the chassis (or ground on the board) to the casing of the pot (isn't that in the instructions?) EDIT: I built the amp so I shouldn't be asking you.......... run a wire from the chassis to the housing of the pot"

 Did you try that???_

 

I tried the suggestion from David White first as I'm sure you'd agree he knows his product. Will open her up and check/fit a ground from the pot and try again. As I said it's no big deal you have to listen for the hum with no music playing. Given the option of risking the amp wih my diy skills or leaving it as is I'd leave it - the WNA is too good to risk.

 Will report back.

 Steve


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_I tried the suggestion from David White first as I'm sure you'd agree he knows his product. Will open her up and check/fit a ground from the pot and try again. As I said it's no big deal you have to listen for the hum with no music playing. Given the option of risking the amp wih my diy skills or leaving it as is I'd leave it - the WNA is too good to risk.

 Will report back.

 Steve_

 

I'll bet you a can of beer that grounding the pot will be the solution 
	

	
	
		
		

		
		
	


	




 just remove the knob, loosen the pot fixing nut off.... attach a wire between the washer and pot housing and tighten the pot fixing nut up again (in effect you are clamping the wire in between the washer and aluminium pot housing)....... run the wire to ground and your problem will be solved I guarantee it 
	

	
	
		
		

		
		
	


	




 Some people solder a wire onto one of the screws at the back of the pot and you could go down that route but you risk melting some of the plastic pot housing if you make a pigs ear of it so clamping between washer and housing is your best bet...... if you want to try a dry run then simply open the top up, attach a wire to ground and touch the other end of the wire on the pot housing to see if it rectifies the situation...... if it does then you can make a permanent connection... will take you 5 minutes Steve 

 All the best

 Mike.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_I'll bet you a can of beer that grounding the pot will be the solution 
	

	
	
		
		

		
		
	


	




 just remove the knob, loosen the pot fixing nut off.... attach a wire between the washer and pot housing and tighten the pot fixing nut up again (in effect you are clamping the wire in between the washer and aluminium pot housing)....... run the wire to ground and your problem will be solved I guarantee it 
	

	
	
		
		

		
		
	


	




 All the best

 Mike._

 

Will do. The wife is hovering over me now as she wants to go shopping. How do I put up with her interfering (ouch she has just hit me!) 
	

	
	
		
		

		
		
	


	




 will get back from shopping and give it a go.

 Cheers

 Steve


----------



## PinkFloyd

I've got a window to paint will be back later to see if grounding the pot has worked for you....... have a good shopping trip!


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_I've got a window to paint will be back later to see if grounding the pot has worked for you....... have a good shopping trip!_

 

Shopping completed. Visited Maplins for some bits & pieces so not all bad.

 The hum was a grounding issue - connected the pot to the rca ground and all now resolved.

 Thanks for the usual excellent service.

 Steve


----------



## Bassivus

What do you say about this trick with output caps for WNA? Quite expensive thou 
	

	
	
		
		

		
		
	


	




 Thread: WIMA MKS-02 PCM2.5 caps in US?

  Quote:


  Originally Posted by *doobooloo* 
_Actually, I just cancelled the order for four 100uF 6.3V NX blackgates from Handmade to order eight 47uF 6.3V NX Hi-Q blackgates from kyoto-electro. Not only is this cheaper, but with four blackgates per dac, I can pair them in "Super-E" configuration:






 In case one isn't familiar with the concept, here is what the blackgate website says:

What is the "Super-E-Caps"? 

 A pair of nonpolarized Black Gate electrolytic capacitors are particularly connected in parallel or in series so that each one of the capacitors cancels the internal magnetic flux generated by the other, thereby completely eliminating internal resonance and decreasing total impedance to absolute zero as the frequency increase.

 Hopefully this will further lower distortion and any other negative side effects of having electrolytic capacitors in the signal path._


----------



## jnewman

Quote:


  Originally Posted by *Bassivus* 
_What do you say about this trick with output caps for WNA? Quite expensive thou 
	

	
	
		
		

		
		
	


	




 Thread: WIMA MKS-02 PCM2.5 caps in US?_

 

I've read the same thing. I'll probably be doing it in my WNA, just haven't gotten around to ordering yet.

 I'm still bypassing with solen's, though.


----------



## Bassivus

jnewman,
 what values you think would be good to go for this? Is 22uF/6.3V to small?


----------



## jnewman

Quote:


  Originally Posted by *Bassivus* 
_jnewman,
 what values you think would be good to go for this? Is 22uF/6.3V to small?_

 

As long as your gain is under about 4.5, the 6.3V is just enough.

 I have single 22uF coupling caps in now, and the amp sounds very, very good - but I haven't tried anything larger yet either, so I can't really tell you. The size of the values is particularly important with low impedence headphones, but as a general rule at least 100uF coupling caps are recommended on the output side. I think I'm going to use two 100uF's 6.3V NX's and a Solen 1uF per channel.


----------



## PinkFloyd

Hey Steve,

 I spent all day today finishing off this WNA and experienced the same "hum" issue that you were experiencing!






 The hum only manifested itself when the Volco was set to zero and seemed to get louder the closer I got to the amp..... if I touched the case it would buzz and if I waved my hand across the amp it would buzz and whine..... the second the volco was notched up from zero the hum would disappear....... even wiggling the headphone cable or moving slightly to the left or right would induce hum at zero volco setting....... weird!

 Obviously some grounding issue so it was out with length of wire terminated with crocodile clips...... after a bit of investigative prodding it, indeed, did prove to be a grounding phenomenon.

 The solution in my case was to remove the insulating washer from one of the phono sockets, attach a wire onto the phono earth tag and run it to the front panel..... I clamped it onto the front panel by affixing it with a circular crimp connector to the chrome plated LED bezel.... you can see the ground wire from the pic (it's the grey one)
















 Pics aren't very clear as It was raining all day so I had to take them under artificial lighting but I'll upload some better ones when the rain stops 
	

	
	
		
		

		
		
	


	




 Anyways, that got rid of the hum for me and the amp is now as quiet as a mouse and sounding absolutely superb.

 I used some Bennic 25V 12uF bipolar output caps and I do believe they sound ever so slightly better than the ALCAPS..... not a lot in it but another cap well worth shortlisting.

 I used ELNA Starget 35V 100uF decouplers and, again, no complaints. 

 The pot has been treated with rainbow foil just to be on the safe side 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## StevieDvd

You 'hum' was obviously worse than mine.

 The solution of grounding the volco and case seems to have done the trick for me though even if not grounded it was no where as bad as your case (pun intentional).


 The number of WNAs is increasing but are any two the same?

 Steve


----------



## PinkFloyd

*[size=large]Output cap misprint [/size]*


 On the matter of output caps, I've been in communication with Dr. White and it seems there has been some confusion (a misprint in the manual) regarding them 
	

	
	
		
		

		
			





 Here's the deal:

 With 300 ohm cans you should be using about 47uF

 Headphones with an impedance above 400 ohms use 22uF

 Headphones with an impedance below 400 ohms use 100uF

 Headphones with an impedance of 8 ohms use 1000uF

 You can see from the above that this will be pretty inconvenient if you own a few pairs of headphones with different impedances so if you have say a 32ohm pair of Grados and a 300 ohm pair of Sennheisers it's recommended you fit 1000uF output caps. 1000uF will cater for all impedances and will still give you all the benefits of the LM6171's.

 I'd recommend that anyone who has fitted the recommended 4.7uF caps (should have read 47uF in the manual) changes them to 1000uF in order that the amp is compatible with all impedances of headphone. For instance if 12uF caps are fitted and you use 300 ohm Sennheisers then you'll probably be getting roll off from about 35-40Hz.

 The output cap Dr. White recommends is the Nitai non polar they are very compact, affordable and sound good too....... a 1000uF polypropelyne would be out of the question as it would be the size of a house brick and that's _if_ you could find one in such a high value.





 Nitai non polar cap.

 Remember, you need only fit a 1000uF if you want the amp to drive phones from 8 - 600 ohms...... if you are using 300 ohm Sennheisers then 47uF will do.


----------



## jpmoon

I have been poised to query the output capacitor value after playing around with the numbers in 1/2(pi)RC. I've also just swapped 100uF Nitai for the same value from Alcap, just to see if I could hear the difference. Much to my surprise, I can.

 I'm using HD600's so not too much of an issue there, plus my 'speaker' listening has been improved by using the WNA. I suspect by the 'effect' of the O/P capacitor. The question I'm now faced with is.......

 I think I'll measure the DC offset before going any further, then maybe I'll try driving my amp through a film capacitor (if I can lower the input impedance enough to keep the LM6171 from oscillating but still have the roll of around 20Hz). Then I suppose I'll have to try some other opamps (just to be sure).

 Best wishes, John.


----------



## PinkFloyd

EDIT: AD-8605 WNA reverting back to LM-6171 WNA see below:


----------



## jnewman

Ah, but is it the AD8065's making it sound better or the extra rainbow foil over the input traces?


----------



## Alick

Ah Mike...just when I'd decided the lid was staying on. 
	

	
	
		
		

		
		
	


	




 Actually, I'm quite chuffed that you've found a way of dispensing with the output cap's without losing the lovely LM6171 sound. My WNA sounds absolutely wonderful, but I've always had this nagging feeling that the output cap's are not the most elegant solution and that the WNA design had even more to offer. Looks like I was right. OK, I need to get some AD-8065's. A few questions then.

 1. Where did you source the AD-8065's? I've looked on RS, Farnell and Rapid; no luck.
 2. Ditto the Browndogs? (Am I right in thinking these are just SMT to DIL adapters? I've been away from this for a while...).
 3. The output cap's can come right out? Low offset then?
 4. Is the AD-8065 compatible with the class-A mod's? Any changes necessary?

 Cheers

 Alick


----------



## PinkFloyd

EDIT: AD-8605 update after prolonged listening below:


----------



## PinkFloyd

EDIT: AD-8605 update after prolonged listening below:


----------



## PinkFloyd

EDIT: AD-8605 update after prolonged listening below:


----------



## PinkFloyd

[size=xx-large]AD-8605 update:[/size]



 Edit: 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 
	

	
	
		
		

		
		
	


	




 This audio lark is enough to drive you insane


----------



## flecom

did you ever try the LM7171?


----------



## Alick

Mike 

 That LC Audio Technology link was very interesting. I've contacted them and they are happy to ship orders to the UK. They do AD8065's already mounted on DIP carriers (with silver/Mica decoupling cap's) for just over €20 a piece and LM6172s for a tad over €5 each. Does anyone know if the LM6172's would need the decoupling cap's?

  Quote:


 as I said above I'm not sure if the improvement is due to the extra capacitance or the actual signature of the cap but the cerafine works for me..... I can send you a couple to try Alick. 
 

If I do remove the lid, I might take you up on your latest kind offer. I'm just starting to worry that this might be a cynical plot so you can claim ownership when you've supplied half the components in my amp...


----------



## PinkFloyd

read 3 posts up 
	

	
	
		
		

		
		
	


	




 Alick.


----------



## Alick

Thanks for the revised opinions Mike. Your credibility has been enhanced by your willingness to question your own position publicly. I may be fitting the evidence to my pet theory, but I'm wondering if the improvements you saw with the AD-8065 (all be it with uncomplicated music) could be related to the lack of output capacitors and the muddiness with complex pieces (relative to the LM6171) related to the AD's poorer slew rate? That being the case, is there a 'holy grail' out there which gives us everything? A really fast, stable chip which provides a low DC offset in the WNA circuit? Could it be the LM6172?


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Thanks for the revised opinions Mike. Your credibility has been enhanced by your willingness to question your own position publicly._

 

My fault not a good idea to judge a chip just on a couple of recordings... I should have listened to everything first and _then_ comment 
	

	
	
		
		

		
		
	


	




 I may be fitting the evidence to my pet theory, but I'm wondering if the improvements you saw with the AD-8065 (all be it with uncomplicated music) could be related to the lack of output capacitors and the muddiness with complex pieces (relative to the LM6171) related to the AD's poorer slew rate? That being the case, is their a 'holy grail' out there which gives us everything? A really fast, stable chip which provides a low DC offset in the WNA circuit? Could it be the LM6172? [/QUOTE]

 I certainly wouldn't roll an LM6172 in Alick as it's a dual chip the "2" standing for dual the WNA only takes single chips.... one per channel.

 What value output caps are you using? try upping them to the recommended dosage, I'm just waiting for the 470uF ALCAPS to arrive and will let you know if they make any improvement.

 Thing is, the WNA is a superb sounding amp and if there_ is_ something better than the LM6171 then surely David would have used it.... I remember what the WNA sounded like with the AD 8610, OPA 627, AD 825.... believe me the LM6171 is a HUGE improvement over those chips and they are considered the market leaders!


----------



## Alick

Quote:


 I certainly wouldn't roll an LM6172 in Alick as it's a dual chip the "2" standing for dual the WNA only takes single chips.... one per channel. 
 

Doh! 

 Note to self. Check basic facts before posting and making an arse of one's self.


----------



## Bassivus

Hey Pink,

 From your latest pics I see that now you use P4 for the LED. I can see there is "something" under heat shrink before LED. Do you use diode (I saw it somewhere on your site) and resistor or just resistor? What value resistors do you use? I also read somewhere on the net the debates about distortion introduced by led; so the question is: do you notice any audible differences in the way of connecting the LED? Sorry for so many questions at once...


----------



## PinkFloyd

Quote:


  Originally Posted by *Bassivus* 
_Hey Pink,

 From your latest pics I see that now you use P4 for the LED._

 

Hi Bassivus, P4 is convenient and a great tap to power the LED from.

  Quote:


  Originally Posted by *Bassivus* 
_ I can see there is "something" under heat shrink before LED. Do you use diode (I saw it somewhere on your site) and resistor or just resistor? What value resistors do you use?_

 

The object hidden under the heatshrink is a 4k7 resistor (connect to long leg of LED and to + at p4) this gives a soothing light intensity and doesn't burn your retinas when you look at it 
	

	
	
		
		

		
		
	


	




 As to the diode, this was something that was recommended for use with the Williams Hart Chiarra amp...... fiting an IN4003 diode across the LED as shown is supposed to prevent return EMF from blowing the LED... it won't do any harm fitting one if you wish but it's not necessary with the WNA to my knowledge.







  Quote:


  Originally Posted by *Bassivus* 
_ I also read somewhere on the net the debates about distortion introduced by led; so the question is: do you notice any audible differences in the way of connecting the LED? Sorry for so many questions at once... 
	

	
	
		
		

		
		
	


	


_

 

Yes, I've read many articles on LED's causing distortion but whether or not your ears can pick up the miniscule amount of distortion (if any) a LED introduces is another thing. I prefer the reassuring glow of a light emitting diode.... one, it gives me a visual alert that the amp is switched on and secondly it adds to the overall appearance of the amp and gives a bit of added eye candy.

 The gspaudio solo originally came without a LED and it was a real pain in the **** checking the mains socket to see if the amp was switched on or off...... it also didn't "feel" right without a LED glowing on the front panel.... some love LED's and others hate them..... if in doubt, leave them out.

 Mike.


----------



## Bassivus

PinkFloyd,

 Thanks for sharing with us "the secrets hidden beneath a heatshrink" 
	

	
	
		
		

		
		
	


	




 I'm planning to put those polarized pins supplied by David so I can experiment easily connecting and disconnecting the LED to see if I can hear any differences.


----------



## PinkFloyd

I fitted the 470uF ALCAPS and replaced the LM6171's and the added capacitance has brought about much deeper bass with more impact and slam.

 This is the real deal and my jaw dropped to the floor when I heard the amp with the 470uF output caps in the circuit...... boy it sounded good with 12uF output caps but now it sounds nothing short of fantastic! 

 I wire wrapped around the legs of the caps first off to provide a good mechanical joint and then flooded with solder... fixed them to the board using a cable tie sticky back holder and fixed them together with double sided sticky tape and secured with a strong cable tie so they are very secure indeed 
	

	
	
		
		

		
		
	


	




 Well, the sound now is just so wonderful and I strongly recommend that anyone with output caps below 100uF whips them out and replaces them with something beefier.... it really makes a night and day difference!


----------



## StevieDvd

OK where do we get these caps in the UK?

 I need to order an LM6171 (Whitenoise only in UK?)
 A set of caps as above (the secret Pinkie supplier)
 A TLE2426CLP (RS Components) for a cmoy not the WNA
 Nice new case (Maplins/Farnell)

 Why is it so difficult to get them all at the one place - it's a conspiracy right to increase the profits of the Post Office (sorry Consignia) 
	

	
	
		
		

		
		
	


	




 Is there somewhere in the UK that would do sexier aluminium cases or machines fronts for the hammond ones?

 The WNA should look as good as it sounds.


----------



## Alick

Farnell do the LM6171 at £2.95. They also do a shedload of cases, but I don't know if any will take your fancy. I want to get ALCAPs too; Mike? Another option would be to get the case and LM6171s from WNA as they now do a pre-drilled case, but I haven't seen it.


----------



## StevieDvd

Thanks Alick,

 Hopefully Pinkie will put us straight on the caps and may even know what the WNA case looks like.


----------



## PinkFloyd

I get my caps from Cricklewood great place and a great bunch of guys so buy with confidence 
	

	
	
		
		

		
		
	


	




 I should be able to show the official WNA enclosure shortly as I may be building a complete WNA kit.... will keep you posted. From what I can gather the official WNA enclosure is a high quality black anodised aluminium clam shell type and you can fit it in the palm of your hand.

 WNA sell the LM6171 at £3.50 each which is a very good price compared to Farnell who have a minimum order of £20 policy and charge quite a lot for delivery also. WNA charge £1.50 for postage and packing so two LM6171's would set you back £8.50 including postage and packing


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_I need to order an LM6171 (Whitenoise only in UK?)
 A set of caps as above (the secret Pinkie supplier)_

 

Hi Steve,

 If I remember correctly your WNA is 2 x LM6171 and an OPA 627 BP in the rail splitter isn't it?

 The output caps in yours will be 25uF 50V +/- 10% ALCAPS correct? if they're the 25uF ALCAPS then crank them up to 100uF for use with HD6** and 470uF if you're listening to 32 ohm cans.... if you're a 32ohm to 300ohm owner then 470uF is more than enough to cater for these impedances....... if you're an 8ohm owner then 1000uF will be necessary but I doubt 1000uF ALCAPS would fit in your enclosure... the Nitai 1000uF is very small and would fit in no probs......... sounds great but IMO the ALCAP just has the last word in finesse but it comes at a greater cost and is much larger!


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Steve,

 If I remember correctly your WNA is 2 x LM6171 and an OPA 627 BP in the rail splitter isn't it?_

 

Yep.

  Quote:


  Originally Posted by *PinkFloyd* 
_The output caps in yours will be 25uF 50V +/- 10% ALCAPS correct? if they're the 25uF ALCAPS then crank them up to 100uF for use with HD6** and 470uF if you're listening to 32 ohm cans.... if you're a 32ohm to 300ohm owner then 470uF is more than enough to cater for these impedances....... if you're an 8ohm owner then 1000uF will be necessary but I doubt 1000uF ALCAPS would fit in your enclosure... the Nitai 1000uF is very small and would fit in no probs......... sounds great but IMO the ALCAP just has the last word in finesse but it comes at a greater cost and is much larger!_

 

[/QUOTE]
 So would these alcaps be OK? I'll take up the challenge of fitting them in. Thogh I use HD6** you never know what else might come along can wise!


----------



## PinkFloyd

There has been nothing other than good news emerging from WNA HQ this past month, first there was the announcement of the new "complete" kit and now they are offering a Battery pack PSU either in Kit form or fully assembled and tested.

 The battery pack is similar in dimensions to the amp enclosure.. the battery holders are little push to release trays that open from the outside of the case there is no need to open the case to change batteries!

 It uses 4 rechargeable PP3 9v batteries in "series parallel" to give an 18V supply and Dr. White reckons you should get 4 hours of listening from a fully charged set of PP3's

 The improvement in sound quality is apparantly "very significant" and I don't doubt this to be the case as battery power is reputed to be the best for sound quality.

 Dr. White is certainly very pleased with the improvements the battery PSU brings about and I quote:

 "The instruments on complex tracks are now even more obviously separated and I've heard things that I've never noticed before ( again ). Its a bit like the effect of replacing and AD8065 with a LM6171 only you're starting from a LM6171 ! Thoroughly recommended."

 The uprated output caps have improved the WNA considerably and if the battery pack can bring about the same increase in performance then I'll be ordering one forthwith.

 I always thought that rechargeable batteries were a pain in the butt having to wait 24 hours for them to recharge but things have improved these days and they charge in no time at all so I'll definitely be giving this battery pack a go....... I do about 8 hours listening per day so would probably be best with 12 rechargeable PP3's which I could put on charge each night... that would give me enough juice on tap for 12 hours of listening.

 Does anyone know if there is a battery charger that could charge 12 x PP3's up in one go or would I have to buy 3 seperate chargers? As I say, it's been years since I used rechargeable batteries but if the WNA battery pack improves the sound of the amp _that_ much then I'm more than willing to convert from AC/DC PSU to WNA battery power 

 All the best.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_So would these alcaps be OK? I'll take up the challenge of fitting them in. Thogh I use HD6** you never know what else might come along can wise!_

 

They're the ones Steve 
	

	
	
		
		

		
		
	


	




 If you're happy with HD6** then 100uF - 150uF will be more than enough....... 1000uF covers all eventualities but are you ever likely to be driving 8 ohm phones?


----------



## SHLim

Hope you all don’t mind if I happen to reaked an old questions as I just start reading this post and might miss a bit in the 16 pages of info. I am interested in this headamp kit and would like to use it as stereo preamp at the same time. Earlier post did mention that LM6171 will cause the power amp to oscillate. Has a work around being found? 
 What about the issue about needing to have a load (connected to headphone) when the amp is power on? 

  Quote:


  Originally Posted by *PinkFloyd* 
_The battery pack is similar in dimensions to the amp enclosure.. the battery holders are little push to release trays that open from the outside of the case there is no need to open the case to change batteries!_

 

Is this mean it has a build in charger? If so, can I charge the battery and listen to music at the same time?

 TIA,
 Sam


----------



## jnewman

Quote:


  Originally Posted by *SHLim* 
_Hope you all don’t mind if I happen to reaked an old questions as I just start reading this post and might miss a bit in the 16 pages of info. I am interested in this headamp kit and would like to use it as stereo preamp at the same time. Earlier post did mention that LM6171 will cause the power amp to oscillate. Has a work around being found? 
 What about the issue about needing to have a load (connected to headphone) when the amp is power on? 



 Is this mean it has a build in charger? If so, can I charge the battery and listen to music at the same time?

 TIA,
 Sam_

 

For the needing to have a load when the amp is turned on, you can get a switched headphone jack that and add 100ohm resistors that will be put across the outputs when there's nothing plugged in.

 I'm not sure why the LM6171 would cause a power amp to oscillate - I must've missed that too.

 I think the last part means you can take the batteries out without taking the case apart.


----------



## Bassivus

Hi,
 for that oscillation question try reading page 12 of this thread, from post #282 and on.
 Now bringing that out I would like to ask a question. 
	

	
	
		
		

		
			




 In post #284 PinkFloyd quotes Dr.White:"...The idea of using a film capacitor across the opamp +ve and -ve power pins is a good one - I do this on my tone control stage and use 1uF stacked film caps, the ones with the exposed end metallization..." My question is: does the *Wima 1uF MKS polyester* fit the description above?


----------



## damitamit

Well I've finally got the money and the time to make a WNA!

 So I think I'm gonna order a audiophile kit with LM6171s from David and have a crack at building that.

 Hopefully it should be quite a step up from my Ra-1 clone, for powering HD600s.

 Amit


----------



## PinkFloyd

I've just received a photo of the official WNA kit amp and thought you guys would like to have a peek under the bonnet 
	

	
	
		
		

		
		
	


	




 This is the £150 "total" kit which comes with everything you need and includes black anodised aluminium clam shell enclosure, Welwyn RC55Y resistors, ALPS Blue Velvet potentiometer, gold plated teflon insulated Phono sockets, LM6171 operational amplifiers, polypropelyne EVOX capacitors, high quality transistors, heatsinks..... _and_ a PSU 
	

	
	
		
		

		
		
	


	




 I'm absolutely blown away by Dr. White's technique of routing the wiring and the neatness and clean layout is a superb.... an absolutely _top_ class example of how it should be done and a great reference model for WNA builders 
	

	
	
		
		

		
		
	


	




 It may be overkill (considering I've got 4 amps 
	

	
	
		
		

		
		
	


	




 ) but I'm ordering one of these kits from WNA tomorrow just to emulate that layout! 





 Higher resolution pic HERE


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_Well I've finally got the money and the time to make a WNA!_

 

Nice one..... time _and_ money are a good combination 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *damitamit* 
_So I think I'm gonna order a audiophile kit with LM6171s from David and have a crack at building that._

 

Mee too....... the WNA "complete" kit has got me salivating (stop me someone! do I need another WNA amp? probably not but those dinky black resistors are hard to ignore 
	

	
	
		
		

		
		
	


	




 ) 

  Quote:


  Originally Posted by *damitamit* 
_Hopefully it should be quite a step up from my Ra-1 clone, for powering HD600s._

 

The WNA and HD600 / HD650 is a great partnership...... 

 All the best.

 Mike.


----------



## Madcat05

wow that wiring job is beautiful. Must come with practise.

 Do you have any pictures of the front and back panels, PinkFloyd?

 On another note how does this amp handle the AKG K501s?


----------



## PinkFloyd

Quote:


  Originally Posted by *Madcat05* 
_ wow that wiring job is beautiful. Must come with practise._




Agreed...... a superb example.

  Quote:


  Originally Posted by *Madcat05* 
_Do you have any pictures of the front and back panels, PinkFloyd?_

 

Sorry, I don't but I would assume the front and back panels are black anodised aluminium from the photos 
	

	
	
		
		

		
		
	


	




 I'll take some pics of the externals of the amp once I have completed building the "official" WNA kit........... heh, I haven't even ordered one yet but will do so tomorrow.......... give me a few days


----------



## Madcat05

I'm probably going to get myself a pair of K501s next month. I've heard the PIMETA can drive them well, so I won't need to upgrade my amp yet.


----------



## damitamit

That is a very neat layout indeed!!

 I'm planning on getting just the parts kit for £90 (audiophile kit with LM6171s instead of OPA627s). The black case pictured above does look very nice, but i'll prolly save some money and just get a hammond case and alps blue from elsewhere.

 Let us know how building the full kit goes and ofcourse we'll need photo evidence


----------



## PinkFloyd

With room to spare!


----------



## jnewman

Those pretty little black resistors are the same ones I used - they do look pretty nice winking up from the board 
	

	
	
		
		

		
		
	


	




. I have some bigger caps on the way that ought to be here in the next few days - I'll put some pictures up when they get here.


----------



## PinkFloyd

Here are the guts of the Battery PSU kit........ I'll provide details once I get them


----------



## Madcat05

Are those Bulgin battery holders I see in there?

 gee I really wish this amp was good with the K501s, as I'll be getting them soon. 

 I iching to build something, and the WNA seems resonable if I source my own parts, hmm oh well.


----------



## jnewman

Quote:


  Originally Posted by *Madcat05* 
_gee I really wish this amp was good with the K501s, as I'll be getting them soon. _

 

It sounds pretty good with them to me... I'm not sure why Mike doesn't like it with 'em. I can't imagine much in the same component price-range (I spent less than $250 and bought the best (not REALLY unreasonable) quality parts - the little .1% resistors, big blackgate caps, Cardas connectors, etc.) sounding any better - it's clean and detailed without ever getting harsh, and has plenty of punch for me (except when listening to Jurassic 5 - but that's a whole other problem entirely).


----------



## Madcat05

Well headphones first.

 Maybe in the new year I'll build one, although I'd like to audition one before building it.


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_It sounds pretty good with them to me... I'm not sure why Mike doesn't like it with 'em. I can't imagine much in the same component price-range (I spent less than $250 and bought the best (not REALLY unreasonable) quality parts - the little .1% resistors, big blackgate caps, Cardas connectors, etc.) sounding any better - it's clean and detailed without ever getting harsh, and has plenty of punch for me (except when listening to Jurassic 5 - but that's a whole other problem entirely)._

 

The K-501's sound fine with the WNA but IMO it just doesn't activate the K-501's bass the same way the gsp solo does..... I use the solo specifically as a K-501 driver purely for the reason it supplies some serious juice to them.... the WNA / K-501 combo sounds excellent but I just like the added bit of drive the solo gives them.

 WNA and HD-6** is SUPERB and _far_ better than Solo and HD-6** so it's not that I don't like the WNA and K-501 combo it's just that the solo gives the K-501 a bit more bass (read a "bit" more and not truckloads more 
	

	
	
		
		

		
		
	


	




) I'll be trying the WNA with Grado's shortly and, by all accounts, it's a match made in heaven


----------



## PinkFloyd

Quote:


  Originally Posted by *Madcat05* 
_Are those Bulgin battery holders I see in there?

_

 

I don't know what make they are Madcat but I do know the battery pack kit is £35 (not including batteries)


----------



## Alick

Quote:


 I'll be trying the WNA with Grado's shortly and, by all accounts, it's a match made in heaven 
 

The WNA works really well with my SR-80s. Which Grado's are you trying Mike?

 While I'm at it, I've noticed that HD6**'s are available at pretty good prices just now and it's nearly Christmas and she never knows what to get me and I feel like upgrading as the WNA probably deserves it, so I'm tempted to drop some serious hints. Mike, have you ever had the chance to compare the 600's with the 650's? I have seen 600's at £150 and 650's at £210 (which both look like pretty good prices) and I'm wondering if the 650's are worth the extra £60? I need to get over to Edinburgh to do some listening...

 Changing the subject, I was so impressed by the neat job David's done with the wiring of the new kit that I've tracked down what I believe to be the same cable from Maplin and ordered 470 uF ALCAPs from Cricklewood at the same time; they are big! Placed both orders yesterday and they arrived today. Unfortunately the postie needed a signature for the Maplin package so took it away again as no-one was in. Never mind, I'll collect it on Saturday morning. Looks like it's going to be a busy Saturday afternoon. 
	

	
	
		
		

		
			





 I'll post pictures (if it turns out well... 
	

	
	
		
		

		
		
	


	




 )


----------



## StevieDvd

It's tricky to tell from the pictures but the battery case looks around the same size as the new WNA case. They do look like Bulgin battery holders as I managed to get some from Farnell.

 Would like to see some more pics or info to get the actual size n perspective.

 Alick, which maplins part no do you reckon then? I've seen the HD600s at £139 delivered, not sure if I can post the link publicly, PM me if you need the link even for price matching.

 Steve


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_The K-501's sound fine with the WNA but IMO it just doesn't activate the K-501's bass the same way the gsp solo does..... I use the solo specifically as a K-501 driver purely for the reason it supplies some serious juice to them.... the WNA / K-501 combo sounds excellent but I just like the added bit of drive the solo gives them.

 WNA and HD-6** is SUPERB and far better than Solo and HD-6** so it's not that I don't like the WNA and K-501 combo it's just that the solo gives the K-501 a bit more bass (read a "bit" more and not truckloads more 
	

	
	
		
		

		
		
	


	




) I'll be trying the WNA with Grado's shortly and, by all accounts, it's a match made in heaven 
	

	
	
		
		

		
		
	


	


_

 

Ok, now that I can see 
	

	
	
		
		

		
		
	


	




. I guess it's just so far ahead of anything else I've had in my possession for any length of time that it seems amazing.


----------



## Alick

Quote:


 Alick, which maplins part no do you reckon then? 
 

I'm hoping it's this stuff . Of course, I could be barking up the wrong tree. If I am, it's no big deal as I only ordered 4m and it'll come in handy for something. I was ordering some other stuff anyway.
  Quote:


 PM me if you need the link even for price matching. 
 

I will, thanks; that's a seriously good price. I'll wait till I've decided whether to go for the 650s or the 600s, but I'm not really convinced that the 650s will be worth 50% more? I could get a spare pair of SR-80s for not much more! Or Shure E2s to go with the Karma...


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_The WNA works really well with my SR-80s. Which Grado's are you trying Mike?

 While I'm at it, I've noticed that HD6**'s are available at pretty good prices just now and it's nearly Christmas and she never knows what to get me and I feel like upgrading as the WNA probably deserves it, so I'm tempted to drop some serious hints. Mike, have you ever had the chance to compare the 600's with the 650's? I have seen 600's at £150 and 650's at £210 (which both look like pretty good prices) and I'm wondering if the 650's are worth the extra £60? I need to get over to Edinburgh to do some listening...

 Changing the subject, I was so impressed by the neat job David's done with the wiring of the new kit that I've tracked down what I believe to be the same cable from Maplin and ordered 470 uF ALCAPs from Cricklewood at the same time; they are big! Placed both orders yesterday and they arrived today. Unfortunately the postie needed a signature for the Maplin package so took it away again as no-one was in. Never mind, I'll collect it on Saturday morning. Looks like it's going to be a busy Saturday afternoon. 
	

	
	
		
		

		
		
	


	




 I'll post pictures (if it turns out well... 
	

	
	
		
		

		
		
	


	




 )_

 

Hi Alick,

 I haven't bought a pair of HD-650's but I listened to a pair in depth and IMO they are even fatter sounding than the HD-600....... the WNA removes the fatness and lifts the veil from the HD-600......... I'm not sure I want to spend £200+ on the 650's I'm sure the money could be better spent on CD's..... WNA makes my ears happy 
	

	
	
		
		

		
		
	


	




 ASK direct are a great source for HD-600's..... £139 including next day delivery...... I bought mine from them and have nothing but good things to say about them (the company), the L/H driver stopped working after a few months (a cable fault) and they rectified the situation in a matter of days and Sennheiser even fitted a brand new, freshly painted, headband..... it's a long story but you won't go wrong buying from ASK 

 Remember that the Sennheiser factory fire has punted the HD-650's price skyward.... supply and demand. The HD-600's are a superb buy at that price.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I'm hoping it's this stuff . Of course, I could be barking up the wrong tree._

 

Whatever it is....... it comes supplied with the Kit amp.......... I'll hopefully be receiving my "official" WNA kit shortly and will report back then


----------



## StevieDvd

Note that Pinkie and I quoted the same price - mainly because that's where I got mine from. If you print the web price their shop matches it.

 I bought my 590s, 600s & 650s from there any the manager gave me a discount I think I paid £89, £130 and £210 (with a bit of haggling).

 The plan was to sell the 590s, use the 600s on the PC/Headsave Classic upstairs and the 650s on the CD/DAC/WNA downstairs.

 Believe it or not the 590s are my portable set at present as I've yet to try a set of closed 'supraural' portables (I don't like the ones you shove in your ear), I'm in the process of upgrading from a portable cmoy and that should push me towards a new set of portable cans as well.

 Guess the upgrading never does end does it.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Note that Pinkie and I quoted the same price - mainly because that's where I got mine from. If you print the web price their shop matches it.

 I bought my 590s, 600s & 650s from there any the manager gave me a discount I think I paid £89, £130 and £210 (with a bit of haggling).

 The plan was to sell the 590s, use the 600s on the PC/Headsave Classic upstairs and the 650s on the CD/DAC/WNA downstairs.

 Believe it or not the 590s are my portable set at present as I've yet to try a set of closed 'supraural' portables (I don't like the ones you shove in your ear), I'm in the process of upgrading from a portable cmoy and that should push me towards a new set of portable cans as well.

 Guess the upgrading never does end does it._

 

So what do _you_ have to say re: the HD:600 V HD-650??


----------



## Madcat05

Is their any reason why I see the HD600s going for $190 USD used here on the boards and $300+ on retail sites?


----------



## Madcat05

I'm putting together a part list for myself. 

 I'm wondering if anyone could supply me with the part # from Mouser.com for these:

 BD140 PNP transistors
 BD139 NPN transistors
 TO220 Bolt on heat sinks
 Plug in regulated 24V PSU
 75V 150mA signal diode
 120R 0.1% resistor
 10R 0.1% resistor
 100R 0.1% resistor
 220R 0.1% resistor
 1K 0.1% resistor 
 10K 0.1% resistor 
 3K3 0.1% resistor 
 47K 0.1% resistor
 OSCON SA series solid aluminium electrolytic capacitors

 Thanks


----------



## StevieDvd

Quote:


  Originally Posted by *Madcat05* 
_Is their any reason why I see the HD600s going for $190 USD used here on the boards and $300+ on retail sites?_

 

The 300 dollar price must be the full retail, you should be able to find it lower. Here in the UK I could pay £230 for them but you can shop around for them as low as £139.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_So what do you have to say re: the HD:600 V HD-650??_

 

I gave up on that a while ago the CD/DAC/WNA gets the best cans, the PC the next best and the portable the next.

 Everytime I sit down to try and discern the difference I end up just listening to the music, as that's the main use of all this expensive gear I don't see that as a problem.

 I know to my ears that the cans are 650, 600 then 590 but to clinically analyse the difference I find hard and I would hate someone to base an expensive purchase on my ears - after all I still have the 590s!

 My wife and 2 daughters would recommend the 590s and think I'm nuts.


----------



## PinkFloyd

As promised I said I would comment on the £150 "complete" WNA kit as soon at it arrived with me so here goes:

 First off the kit was very well packaged and arrived safe and sound 
	

	
	
		
		

		
		
	


	




 The components were arranged into clear snap lock plastic bags with resistors in one bag, diodes in another, cable in another, opamps in another and so on and so forth... the cable is cut into lengths and each length is marked very clearly ie: "output to jack" etc. The cable is military grade RG178BG coaxial. Both the braid and centre conductor are silver plated and the insulation as well as the dielectric are ptfe.

 Latching pin plugs and sockets are supplied and this will make the kit dead easy to assemble as you can wire all the peripherals up away from the board and simply snap connect everything onto the board when you're ready.... believe me, hardwiring all that wire directly to the PCB is no fun and these latching sockets are a godsend! especially handy if you want to remove the board any time... just unlatch and away you go 
	

	
	
		
		

		
		
	


	




 The component quality is first class, 20K ALPS Blue Velvet potentiometer, Welwyn RC55Y resistors ( £1 each in the UK!!) Evox Rifa polyprop caps, turned pin dip8 sockets, gold plated headphone socket, blue LED with bezel, Rubycon capacitors, high quality transistors, black brushed aluminium volume knob, gold plated teflon insulated RCA sockets, insulated 2.1mm DC socket.... the list is endless...... top quality componentry 
	

	
	
		
		

		
		
	


	




 The enclosure is black anodised aluminium and looks more business like rather than "exotic" it's unassuming and will fit quietly into the background.... it's there to house the electronics and is not a "look at me" sculpture.... a good solid workaday housing is how I would describe it (minimalists will LOVE it)

 The cutouts on the enclosure are spot on and the holes are drilled to precision so there's no need to worry about positioning or drilling as it has all been done for you. WNA have measured everything up to ensure the cable runs are kept to the bare minimum as you'll see from this pic: (if you use that pic as a guideline you won't go far wrong as precisely measured lengths of RG178BG coaxial are supplied with the kit)






 The PCB is rock solid glass fibre and very high quality... fitting the components to it couldn't be easier thanks to the VERY easy to understand construction manual and the component ID screenprinting on the PCB.

 I could go on all night about this kit, I'm really very impressed with every bit of it, and am so glad that WNA have made a "complete" kit available at such a superb price.... I don't want to bore you guys with screeds of typing so will sign off for now.... I'll keep you updated on the build progress of the "complete" WNA kit but for now I'll leave you with a few pics of the kit (please excuse the quality of the photos, my 1 mp camera just doesn't do high resolution 
	

	
	
		
		

		
		
	


	




 ) 

 All the best.

 Mike.


----------



## PinkFloyd

You'll probably get a better idea of the benefits of latching sockets from this picture......


----------



## Magsy

arg! I was going to take the cheap (simple) option but now I don't know, that kit looks damn neat! Plus I'm in the UK..

 The pics are great, any chance you can take a few more of the chassis?

 I can't really find the £150 price @ wna, seems to be £200+ in the pdf. Is it deffo £150 for what you got?

 Thanks!


----------



## Madcat05

I definatly want this kit now, it looks soo easy to build.

 Can't wait to see the finished amp!


----------



## Alick

Quote:


 I can't really find the £150 price @ wna, seems to be £200+ in the pdf. Is it deffo £150 for what you got? 
 

I don't think the new kit's on the WNA site yet. AFAIAA, the £200 kit is the original kit (without case, connectors, etc.) but with stepped attenuators instead of a volume pot', hence the price. The cheap, simple option is still there (mine cost less than £100), but this new kit does look superb and the listed componentry makes it a steal at the price. If I hadn't already built mine, I'd buy it without hesitation. It looks like an extremely well thought out, well spec'd, bargain basement product and as I never tire of saying, the WNA sounds simply wonderful.


----------



## PinkFloyd

Quote:


  Originally Posted by *Magsy* 
_arg! I was going to take the cheap (simple) option but now I don't know, that kit looks damn neat! Plus I'm in the UK..

 The pics are great, any chance you can take a few more of the chassis?

 I can't really find the £150 price @ wna, seems to be £200+ in the pdf. Is it deffo £150 for what you got?

 Thanks!_

 

Yes... definitely 100%.... £150 for the kit and that includes a PSU for whatever part of the world you're in..... The "complete" kit is a recent development and the catalogue doesn't reflect the new low price..... probably best if you contact WNA direct and they will confirm the price....... 

 All the best.

 Mike.


----------



## Bassivus

I am soooooo sorry that this compete kit came to mention just few days after I made my order. WNA stuff came in just 5 days, and for the rest I'm waiting for more than 3 weeks now!


----------



## Magsy

Thanks for the clarification guys!

 I've just bought the emu 0404 on a month I'm not supposed to be buying anything, but I'm ampless atm and the 580's are definately a nono with this unamped 
	

	
	
		
		

		
			





 I'll have talked myself into it by tomorrow


----------



## Bassivus

While I'm waiting for all the parts to arrive I was preparing front plate for my future WNAHA. Here is the sneak preview:
















 It is made to fit as Hammond 1455N1602 frontplate


----------



## damitamit

wow! 
	

	
	
		
		

		
		
	


	




 I cant wait for my audiophile wna kit to arrive now, thou my case wont be as cool as that!


----------



## Madcat05

looks very nice Bassivus


----------



## PinkFloyd

Quote:


  Originally Posted by *Bassivus* 
_While I'm waiting for all the parts to arrive I was preparing front plate for my future WNAHA. Here is the sneak preview:







 It is made to fit as Hammond 1455N1602 frontplate_

 

Whoah! that's beautiful Bassivus, did you carve it yourself and what type of wood is it? That's going to one very special amp 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## Alick

First the bad news; the Maplin cable I suggested a few posts back is totally unsuitable for wiring the WNA. It's a heavier gauge Shark OFC directional cable which will come in handy for something, but not this. Never mind, I only bought 4m so £3.96 isn't going to bust the bank (certainly not by Head-Fi standards. 
	

	
	
		
		

		
		
	


	




 ) With the lid off again, I'm happy I made a better job of wiring up than I'd remembered. It's not up to professional wire-men's standards, but it's not a rat's nest and the soldering's fine.

 Now the good news. I removed the 25uF ALCAPS and replaced them with the 470uF (it was a tight squeeze). I powered on and only listened for a few minutes, but the difference is night and day. Where before the bass was fine, now it's simply stunning. She's burning in at the moment, so I'll give it 10 hours or so and have a serious listening session tonight. I'll post more impressions tomorrow. 

 I wonder where I can get 1000uF and if I can squeeze them in?


----------



## damitamit

Well I'm at my parents house for the weekend in London ( for Diwali celebrations), which just happens to be about 4 miles from Cricklewood electronics.

 So I might go buy some Alcaps in preparation for my WNA for which I havent even ordered the kit for yet!

 150uF will be ok for HD600s, right?

 Might as well while im down here me thinks


----------



## Bassivus

The type of wood is chopping board wood 
	

	
	
		
		

		
		
	


	




 No kidding, I bought it at the flea market as chopping board. It had the nice texture... I was told it is the common beech. I have carved it, color treated (mahogany) and polished it all by myself. It was like this






 before coloring. I liked it in natural also, but decided to go for mahogany tone because in my opinion it fits black aluminum case better.

 Ivica.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_ I removed the 25uF ALCAPS and replaced them with the 470uF (it was a tight squeeze). I powered on and only listened for a few minutes, but the difference is night and day. Where before the bass was fine, now it's simply stunning. She's burning in at the moment, so I'll give it 10 hours or so and have a serious listening session tonight. I'll post more impressions tomorrow. _

 

Nice one Alick!

 the higher capacitance output caps sure do make a difference, what headphones are you using? 470uF is MORE than adequate for HD-600's.

  Quote:


  Originally Posted by *damitamit* 
_Well I'm at my parents house for the weekend in London ( for Diwali celebrations), which just happens to be about 4 miles from Cricklewood electronics._

 

don't tell me....... your parents live in Kingsbury? I lived in Dollis Hill for 30 years (5 minutes from Cricklewood) Cricklewood were my trusty suppliers for everything electronic.... they're a great company and I miss chatting with the guys...... mail order isn't as good  BTW happy Diwali.

  Quote:


  Originally Posted by *damitamit* 
_150uF will be ok for HD600s, right?_

 

MORE than sufficient.... 150uF will be ideal.


----------



## Alick

Quote:


 Nice one Alick!

 the higher capacitance output caps sure do make a difference, what headphones are you using? 
 

Grado SR-80s, hence the great difference.


----------



## damitamit

Quote:


 don't tell me....... your parents live in Kingsbury? I lived in Dollis Hill for 30 years (5 minutes from Cricklewood) Cricklewood were my trusty suppliers for everything electronic.... they're a great company and I miss chatting with the guys...... mail order isn't as good  BTW happy Diwali. 
 

Thanks 
	

	
	
		
		

		
			





 Nope, Edgware (where i've lived for most of my life). Unfortunately didnt get time to go due to too much diwali eating etc. hehe. 
	

	
	
		
		

		
		
	


	




 Do you know what size output caps the wna kit comes with?


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_ Thanks 
	

	
	
		
		

		
		
	


	




 Nope, Edgware (where i've lived for most of my life). Unfortunately didnt get time to go due to too much diwali eating etc. hehe. 
	

	
	
		
		

		
		
	


	



_

 

Not too far away from Cricklewood then 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *damitamit* 
_Do you know what size output caps the wna kit comes with?_

 

Yes, it comes with 220uF as standard and either 470uF or 1000uF are available on request.. they're Nitai non polars and very compact, sound pretty decent too.


----------



## boodi

..how do caps ( and size of caps in uF ) modifies the sound ?..from what i can read do bigger caps means heavier bass in general ..or this is what happens in the WNA ?


----------



## Alick

The simple answer (hopefully); the impedance of capacitors varies with frequency. They have a higher impedance at low (bass) frequencies and a lower impedance at high (treble) frequencies. The higher the capacitance value, the lower the impedance. 

 Now, the output capacitor is in series with the headphone speaker which we will consider to be a resistor (it's actually an inductor but this is the simple answer). This means that the voltage drop across the capacitor (which is greater at low frequency because of the high impedance) results in a lower voltage across the headphone speaker, attenuating power at low frequencies. The effect is more pronounced with low impedance headphones such as Grado's because the voltage drop is directly related to the ratio of the two impedances (speaker and capacitor).

 The ideal solution would be not to have the capacitor at all, but the capacitor's high impedance at low frequencies provides a virtual open circuit at DC providing an effective DC block. The WNA design results in a small DC offset at the output which, if not blocked, would cause a loud 'pop' at switch-on/switch-off and more seriously, bias the speaker cones risking clipping and possibly damage during use.


----------



## PinkFloyd

It was a pretty miserable day here today so I thought it an opportune moment to put the WNA kit together. This was my first experience of the WNA "complete" kit (I have always sourced the parts and enclosures myself) so this was unchartered territory for me 
	

	
	
		
		

		
		
	


	




 I couldn't be arsed standing out in the workshop so decided to populate the PCB indoors listening to some Pink Floyd through my speaker based system..... I was also too lazy to bring the soldering iron and extension cords etc. inside so I decided to build the WNA using a gas powered iron.

 Armed with said gas powered iron and a pair of snips I went to work and had the board populated and soldered in about 45 minutes...... this part of the construction is as easy as pie but I wish WNA had identified the 3.5mA and 5.6mA constant current diodes.... it's not everyone that will understand the markings under a magnifiying glass and It would make things a lot easier if they were labeled.

 45 minutes and some Isopropyl alcohol later (to clean the board with!) the board was fully populated:





 Yeh I know the iron looks huge but I prefer working with large tips... more heat less time spent on the joint. BTW the Irodo pro 120 soldered the WNA on half a tank of gas!





 Time for a new camera... this old 1m pixel just can't stretch to showing fine detail but I can assure you the joints are soldered to the highest quality 
	

	
	
		
		

		
		
	


	




 OK 45 minutes on the board, so far so good. I spent a good hour preparing the wires, latching sockets, connections to the volume control and wiring the head socket up etc..... the board (PCB) is a TIGHT fit and this part of the build is where frustration starts to set in..... there is NO clearance between PCB and potentiometer, the phono socket doesn't clear the 12V tap making it virtually unuseable (especially if you're using largish decoupling caps) the DC socket "just" clears a capacitor.... so on and so forth.

 This really is a very "minor" gripe and for seasoned shoehorners it will pose no problems whatsoever. I do feel the enclosure may be a bit "too" tight for novices and an extra inch all round would make things so much easier. There is literally less than 1 millimeter of clearance in places. I gave up on trying to fit a board securing nut under one of the phono sockets..... impossible unless you have funky fingers 
	

	
	
		
		

		
		
	


	




 Minor gripe over and done with I built the business end of the kit up in no time at all and the majority of time was spent farting about trying to fit a nut onto an inaccessible bolt....... it's all fun and part and parcel of a kit amp but WNA could make it a lot easier to construct if they increased the size of the enclosure by an inch or make provisions boardside for the pot and head-socket.

 How does the gas built WNA sound? out of this world! Maybe it's my imagination but those Welwyn RC55Y's sure do make one hell of a difference ........ dunno what it is but the WNA "kit" just sounds a lot better than a WNA PCB populated with self sourced bits and bobs........ maybe it's a placebo thing I don't know........ I've got two side by side, one in an uber cool enclosure and the other in a workaday, unassuming WNA black box... the WNA in the black box sounds better 
	

	
	
		
		

		
		
	


	




 Maybe it's down to the resistors, who knows...........

 One thing's for sure, the WNA amp can be built in a few hours and it will work when you power it up...... it's consistent and very rarely gives hassle to builders......... I've built quite a few kit amps and can honestly say that the WNA is by far the easiest to build and the most consistent DIY amp I've come across ........ most importantly, the WNA is the best sounding of all the kit amps I have built.


----------



## Madcat05

looks great PinkFloyd, I definatly want to build this kit now.

 Do you think I'd be able to use a peice of plexi glass as the lid, to get a window effect?


----------



## Bassivus

Looks great Mike! Beside this being your first "complete" kit, is this your first WNA with those big 4u7 input caps? Maybe it also has to do with the new sound quality? Quote:


  Originally Posted by *PinkFloyd* 
_........ dunno what it is but the WNA "kit" just sounds a lot better than a WNA PCB populated with self sourced bits and bobs........ maybe it's a placebo thing I don't know........ I've got two side by side, one in an uber cool enclosure and the other in a workaday, unassuming WNA black box... the WNA in the black box sounds better 
	

	
	
		
		

		
		
	


	




 Maybe it's down to the resistors, who knows..........._

 

I hope those black resistors also make the difference because I'm waiting for ages for them to arrive… 
	

	
	
		
		

		
		
	


	




 Ivica


----------



## Alick

I was thinking the same as Bassivus. It might well be the Welwyns making the difference, but I'd be inclined to suspect the different PSU, the 4u7's and the Nitai output cap's will also be contributing. Still looks like a really good kit, although I'm not convinced about the latching pins, preferring to eliminate as many connectors as possible from the signal path. Perhaps some gold PCB wiring posts could be substituted for hard wiring purposes?

 The 470uF cap's in my amp are sounding very good. I might still be tempted to try 1000uF if I can find something suitable.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I was thinking the same as Bassivus. It might well be the Welwyns making the difference, but I'd be inclined to suspect the different PSU, the 4u7's and the Nitai output cap's will also be contributing. Still looks like a really good kit, although I'm not convinced about the latching pins, preferring to eliminate as many connectors as possible from the signal path. Perhaps some gold PCB wiring posts could be substituted for hard wiring purposes?

 The 470uF cap's in my amp are sounding very good. I might still be tempted to try 1000uF if I can find something suitable._

 

It may well be the Welwyns but my money is on the input caps..... I know people hate capacitors in an amp but these polyprop EVOX seem to have injected even more energy into the amp..... I generally avoid using input caps but, in this example, they seem to be doing more good than harm 
	

	
	
		
		

		
		
	


	




 I was originally of the same opinion as you Alick regarding the latching pins but, my word, they make life so much easier (especially if you do a lot of tweaking under the bonnet) you can easily detach the PCB from the enclosure without having to pull the whole mess of spaghetti out in one whole...... if you're certain that you'll NEVER go under the bonnet EVER again then, of course, hardwiring is the way to go...... 

 Looking at the kit today I'm of the opinion that the "close" fit is a very good thing.. as long as WNA can consistently produce the kits to such a close level of tolerance there will be no problems... it's "so" close that a hole drilled 2mm out of spec would cause fitting problems but David says that consistency is assured so that's good news and keeps the size of the amp very compact.... the more I think about it, the more I like the tight fit.... it's not as compact as the smallest hammond, thank god, that was a REAL pig of a shoehorn job..... WNA have obviously thought long and deep and have come up with a Kit that is both compact and great sounding....... I'm going to strip the kit down at the weekend and will report back on how long it takes me to pull the board out 
	

	
	
		
		

		
		
	


	




 I guesstimate 3 minutes but hope to do it in 2 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


----------



## damitamit

WNA audiophile kit is hopefully arriving on Thursday. wooo!

 Just been getting together the other parts needed. Got a Hammond case from my local maplin (its great having a maplin superstore a few mins from here, they always have stuff in stock). 

 Now I'm ordering the pot and other bits from Rapid. They are out of stock of 20K Alps Blue's. 
 Would a 50K pot be ok? Would just the range of control be affected? ( which is ok then).

 Gonna be using Teflon coated 99.99999% pure Silver wire (from the HeadFi group buy) for hook up wiring 
	

	
	
		
		

		
		
	


	




 Amit

 Edit: Ordered a 50K so will find out soon!


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_WNA audiophile kit is hopefully arriving on Thursday. wooo!

 Just been getting together the other parts needed. Got a Hammond case from my local maplin (its great having a maplin superstore a few mins from here, they always have stuff in stock). 

 Now I'm ordering the pot and other bits from Rapid. They are out of stock of 20K Alps Blue's. 
 Would a 50K pot be ok? Would just the range of control be affected? ( which is ok then).

 Gonna be using Teflon coated 99.99999% pure Silver wire (from the HeadFi group buy) for hook up wiring 
	

	
	
		
		

		
		
	


	




 Amit

 Edit: Ordered a 50K so will find out soon!_

 

Nice one Amit 
	

	
	
		
		

		
		
	


	




 10K was the first pot I used but they are as rare as rocking horse crap..... 20K is good and 50K is also good.... if you're using a 10K then it's worthwhile downsizing the 47K input resistors to 10K also.

 The silver wire sounds good, why not twist a thin length of copper wire alongside it to get the best of both worlds 
	

	
	
		
		

		
		
	


	




 What Hammond did you order? The smallest one is an absolute pig to work with (shoehorn city) but the next size up allows enough room to accommodate an ALPS RK27 and other luxuries such as ELNA cerafines and large ALCAPS (screw me Cricklewood must be shifting pallete loads of ALCAPS out.... I called them today and they were out of stock of 470uF the guy said "there's a lot of demand for them at the moment" 
	

	
	
		
		

		
		
	


	




 )

 Have fun building the kit Amit and if you run into any difficulties (which you probably won't) then there's a good pool of WNA builders here to tap into 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


----------



## Alick

Quote:


 they were out of stock of 470uF the guy said "there's a lot of demand for them at the moment" 
 

Maybe I got the last two?


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Maybe I got the last two? 
	

	
	
		
		

		
		
	


	


_

 

probably yes 
	

	
	
		
		

		
		
	


	




 but I get first pick of the "fresh" batch


----------



## damitamit

Quote:


 What Hammond did you order? The smallest one is an absolute pig to work with (shoehorn city) but the next size up allows enough room to accommodate an ALPS RK27 and other luxuries such as ELNA cerafines and large ALCAPS 
 

I got the N77AL, which is the bigger one I think.

 Got an email today from David White. Theres been a delay at the PCB place so I'll be receiving my kit on friday. Probably for the best anyway, as I need to write a couple of thousand lines of Java Swing by the weekend.

 I shall post here if I have any questions when I start building.

 thanks
 Amit

 Ps. If you order a chrome LED bezel (or many other certain items) from Rapid you get 4 Duracell M3 AAs for free!! Its a current promotion.


----------



## StevieDvd

I've just got my Nitai 1000uF Caps from WNA (as well as the LM6171) and wanted to check if the non-polar caps have to be fitted in any particular direction? 

 For example does the long leg go to the pcb or headphone socket (and the same on both the left & right channels)?

 It's a little difficult to tell from the pics of the WNA kit above.

 If some kind soul can confirm I'd be obliged.

 Steve


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_I've just got my Nitai 1000uF Caps from WNA (as well as the LM6171) and wanted to check if the non-polar caps have to be fitted in any particular direction? 

 For example does the long leg go to the pcb or headphone socket (and the same on both the left & right channels)?

 It's a little difficult to tell from the pics of the WNA kit above.

 If some kind soul can confirm I'd be obliged.

 Steve_

 

Fit them anyway round Steve, they are non polar. There will be a long leg and a short one as they build them all in the same package (whether polar or non polar)

 In effect all you are doing is connecting one leg of the Nitai to the sig out and the other leg of the Nitai to the headphone socket.

 Left channel out is connected to the tip of the head socket and right channel out is connected to the ring of the head socket... so from the front of the head out socket the first terminal is ground.. the middle one is ring and the furthest one away is the tip. leave the resistors on the other side of the socket they are a dummy load.

 You're probably best hardwiring a lead to both left and right outs on the board and securing the caps on the board...... run the lead to one terminal of the cap and then run a lead from the other terminal up to the head - socket.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Fit them anyway round Steve, they are non polar. There will be a long leg and a short one as they build them all in the same package (whether polar or non polar)

 In effect all you are doing is connecting one leg of the Nitai to the sig out and the other leg of the Nitai to the headphone socket.

 Left channel out is connected to the tip of the head socket and right channel out is connected to the ring of the head socket... so from the front of the head out socket the first terminal is ground.. the middle one is ring and the furthest one away is the tip. leave the resistors on the other side of the socket they are a dummy load.

 You're probably best hardwiring a lead to both left and right outs on the board and securing the caps on the board...... run the lead to one terminal of the cap and then run a lead from the other terminal up to the head - socket._

 


 Thanks,

 Just putting the soldering iron on so will report back with successful fitting (I hope)


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Thanks,

 Just putting the soldering iron on so will report back with successful fitting (I hope) 
	

	
	
		
		

		
		
	


	


_

 

np Steve you'll have it done in minutes


----------



## damitamit

Got my kit on Friday and populated the board fri eve. Went quite smoothly. 

 The pot hasn't arrived yet so will have to wait til monday to do that and connect all the connectors and power switch and led and drill the case.

 Also, the pcb+parts kit (with LM6171) doesn't seem to come with output caps, which I thought was weird as output caps are recommended with the LM6171 and the kit came with different parts to accomodate the LM6171 (e.g different value resistors).

 Can I connect my HD600s without output caps, if I check the dc offset first to make sure it isnt too high? Anyone know how to check the dc offset?

 Amit


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_Got my kit on Friday and populated the board fri eve. Went quite smoothly. 

 The pot hasn't arrived yet so will have to wait til monday to do that and connect all the connectors and power switch and led and drill the case.

 Also, the pcb+parts kit (with LM6171) doesn't seem to come with output caps, which I thought was weird as output caps are recommended with the LM6171 and the kit came with different parts to accomodate the LM6171 (e.g different value resistors).

 Can I connect my HD600s without output caps, if I check the dc offset first to make sure it isnt too high? Anyone know how to check the dc offset?

 Amit_

 


 Don't, under any circumstances, power a LM6171 WNA up without output caps unless you want to hear oscillation in it's full glory 
	

	
	
		
		

		
		
	


	




 Wait for the output caps 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## damitamit

Ah, thanks for the tip! 
	

	
	
		
		

		
		
	


	




 Well I ordered the Audiophile Kit of David and asked for it be supplied with LM6171s. He therefore supplied the LM6171s and also supplied different resistors for use with the LM6171s and Class A biasing things too (without me asking), so I cant see why the ouput caps didnt come too. 

 Im gonna email him and see if maybe they just forgot to put them in. 

 Amit


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_Ah, thanks for the tip! 
	

	
	
		
		

		
		
	


	




 Well I ordered the Audiophile Kit of David and asked for it be supplied with LM6171s. He therefore supplied the LM6171s and also supplied different resistors for use with the LM6171s and Class A biasing things too (without me asking), so I cant see why the ouput caps didnt come too. 

 Im gonna email him and see if maybe they just forgot to put them in. 

 Amit_

 

Probably a "picking and packing" oversight....... my kit came with the output caps...... I'm sure David will have those caps on your doorstep ASAP once he's been made aware of the shortage. 

 Mike.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_np Steve you'll have it done in minutes 
	

	
	
		
		

		
		
	


	


_

 

Don't know about minutes but it's done now.

 Had also bought a new Hammond case to get the ally front/back panels so it's all done now except for a posh volume knob. WIll be looking for one of those silver ones with a black rig if you know the ones I mean.

 Just about to connect it back up to the Dac and 650s and give it a couple of hours of run-in/listen-in 
	

	
	
		
		

		
		
	


	




 Thanks for the usual help - you know you are appreciated don't you!


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd * 
_ you know you are appreciated don't you!_

 

same to you too man........ peace 
	

	
	
		
		

		
		
	


	




 Pink.


----------



## PinkFloyd

I used this knob on a Chiarra........... weighs a ton but oooh so sexy and only cost a fiver:








 I got it from www.audoikit.it check their knob section.


----------



## Alick

...and if you ever sell the Chiarra on eBay, you could stand naked while taking the pho... maybe not.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_...and if you ever sell the Chiarra on eBay, you could stand naked while taking the pho... maybe not. 
	

	
	
		
		

		
		
	


	


_


----------



## damitamit

Received an email from Dr White regarding the ouput caps.
 Output caps are not included in the pcb level kits, only in the cased kit.

 Soooo does anyone know (im sure Pinkie does),

 Do the output caps need to be non-polar? Im just looking at caps available at Maplin, that I can use until I can order some Alcaps.

 Do the output caps have to be Electrolytics or can they be other types of caps?

 Amit


----------



## Alick

The output cap's must be bi-polar and you are unlikely to find any non-electrolytics of the right value which will fit in your case. I don't think Maplin do any non-polar electrolytics.

 If it's any consolation, Cricklewood shipped next day when I ordered my ALCAPs, so you shouldn't have to wait too long.


----------



## damitamit

Thanks for the info Alick.

 Yeh, I thought so about Maplin. Couldn't seem to find any.

 If i was at home it would be no problem, I could ride down to Cricklewood, but I'm in Nottingham during term time. 

 Oh well. Seems the WNA will come alive on tuesday now!


----------



## PinkFloyd

you can get the Nitai non polars here 42p for the 16V 1000uF or a very good 15p for the 16V 220uF

 The 1000uF are bigger than the 220uF so you won't be able to mount them on the head socket like this:







 The Nitai are darned good caps for the money and they have one great advantage.... their size.... a comparable 220uF ALCAP would cost about £2.50 and would be about 10 times the size..... if you've got the space in your enclosure then the ALCAPS do have a more organic sound.

 Info about ALCAP manufacturing process and reversible caps here

 CPC also do Samwha non polars.... 220uF is the highest they go up to and they are about a quid each..... I used these in many X-can V2 mods and then found the cheaper Nitai's a couple of years ago and gave them a go (15p each!) and they sounded identical so I used them in all subsequent V2 mods to great effect....... the Samwha may sound better than the Nitai used as an "output" cap however and they may be worth a whirl....... SAMWHA here


----------



## damitamit

Yeh, I noticed them at Rapid earlier today.

 If I'd known I would've added them to my rapid order i made at the beginning of the week, without a 2nd thought, just in case.

 Oh well.

 So its either £5 incl postage for Nitais from Rapid.

 Or £8 incl postage for Alcaps from Cricklewood.

 EDIT: It will have to be the Alcaps. Rapid won't ship to my non-cardholder address.


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_Yeh, I noticed them at Rapid earlier today.

 If I'd known I would've added them to my rapid order i made at the beginning of the week, without a 2nd thought, just in case.

 Oh well.

 So its either £5 incl postage for Nitais from Rapid.

 Or £8 incl postage for Alcaps from Cricklewood.

 EDIT: It will have to be the Alcaps. Rapid won't ship to my non-cardholder address._

 

crap, if I had any Nitai's or ALCAPS here I would have sent you them..... I'll be placing a rapid order on Wednesday and will gladly order a few Nitais up and send you some different values to play with if you can wait a few more days.... £5 seems crazy for a few pence worth of caps.

 Mike.


----------



## damitamit

Thanks for the offer Mike!

 I just found out theres a RS Components Trade Counter about 1 min from uni, so I mite try there. I'll be able to get them Tues then for a few pence. However I think you need to bring proof of being a company so it might not work.

 Ill let you know if I am going to take you up on that kind offer. 
	

	
	
		
		

		
		
	


	




 thanks
 Amit


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_Thanks for the offer Mike!

 I just found out theres a RS Components Trade Counter about 1 min from uni, so I mite try there. I'll be able to get them Tues then for a few pence. However I think you need to bring proof of being a company so it might not work.

 Ill let you know if I am going to take you up on that kind offer. 
	

	
	
		
		

		
		
	


	




 thanks
 Amit_

 

I'll include them in my order anyway


----------



## StevieDvd

I got my Nitai 1000uF from WNA together with 2 LM6171 and the total came to £11.50

 Can't complain as the postage would have been high if I'd ordered them elsewhere on their own.

* Update,*

 Have now got my Dac running off 12v SLA battery with an on/off switch and Schottky diode in-line to prevent accidents. So it's not been a bad weekend for me diy wise, though my soldering is still not up to Pinkie standards.

 It all sounds better but where the improvement comes from I can't be sure it may be a combination of all LM6171s, the changed caps and/or the cleaner supply to the DAC (maybe it's the new case 
	

	
	
		
		

		
		
	


	




 )

 I'll allow some more burn in time for the new components but to me it's seems that any improvement is going to be hard. 

 That just leaves the new knob and a switch box so I can try with/without the Dac to hear the difference.


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_I got my Nitai 1000uF from WNA together with 2 LM6171 and the total came to £11.50_

 






 I thought your amp was 2 x LM6171 and an OPA 627 "BP" in the rail splitter? you bought "2" LM6171's?

  Quote:


  Originally Posted by *StevieDvd* 
_Can't complain as the postage would have been high if I'd ordered them elsewhere on their own._

 

£7.00 for 2 x LM6171, £3.50 for postage and a quid for the two Nitai's...... sounds VERY reasonable.


  Quote:


  Originally Posted by *StevieDvd* 
_though my soldering is still not up to Pinkie standards._

 

 I'm sure it is 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *StevieDvd* 
_It all sounds better but where the improvement comes from I can't be sure it may be a combination of all LM6171s, the changed caps and/or the cleaner supply to the DAC (maybe it's the new case 
	

	
	
		
		

		
		
	


	




 )_

 

It's probably best to tackle one tweak at a time, that way you'll know if you're onto a winner.......... try retrofitting everything and start off replacing the Nitai caps with ALCAPS........ you should find the improvement very noticeable. It's not a good idea to "batch" mod. 


  Quote:


  Originally Posted by *StevieDvd* 
_I'll allow some more burn in time for the new components but to me it's seems that any improvement is going to be hard._

 

 see above 
	

	
	
		
		

		
		
	


	




 Have fun Steve 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_





 I thought your amp was 2 x LM6171 and an OPA 627 "BP" in the rail splitter? you bought "2" LM6171's?_

 

Just in case I ordered a spare. 

  Quote:


  Originally Posted by *PinkFloyd* 
_£7.00 for 2 x LM6171, £3.50 for postage and a quid for the two Nitai's...... sounds VERY reasonable._

 

Sorry i thought the postage was £1.50 (from your post earlier in this thread - that would have made it three quid.

  Quote:


  Originally Posted by *PinkFloyd* 
_ I'm sure it is 
	

	
	
		
		

		
		
	


	


_

 

Believe me it's not.

  Quote:


  Originally Posted by *PinkFloyd* 
_It's probably best to tackle one tweak at a time, that way you'll know if you're onto a winner.......... try retrofitting everything and start off replacing the Nitai caps with ALCAPS........ you should find the improvement very noticeable. It's not a good idea to "batch" mod. _

 

I did a little check after swapping the rail splitter op-amp and a brief 3 hour listen last night before I'd touched the DAC today. I can't put a percentage figure on the difference. I can say that I can now hear extra detail that I had not heard before- so given it's improved I won't risk my soldering skills 
	

	
	
		
		

		
		
	


	




 on a retrofit.

 Should be good for a while now (famous last words).


----------



## damitamit

Quote:


  Originally Posted by *PinkFloyd* 
_I'll include them in my order anyway 
	

	
	
		
		

		
		
	


	


_

 

If you did order them in the end, could I possibly have a couple? Didn't manage to get them from anywhere else in the end.

 I can paypal/bank transfer you some monies...

 WNA Progress:

 The panels have been drilled and all the parts are here except output caps. Also Im planning on have a knob-mounted power led! (thats sounds wrong!
	

	
	
		
		

		
		
	


	




) 
 But that isnt going to plan, as the knob i drilled the hole in doesnt actually fit on a Alps Blue. So im gonna have to try with a different knob...

 Then just gotta solder everything up when I have some time, and it should be complete!

 Amit


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_If you did order them in the end, could I possibly have a couple? Didn't manage to get them from anywhere else in the end.

 I can paypal/bank transfer you some monies...

 WNA Progress:

 The panels have been drilled and all the parts are here except output caps. Also Im planning on have a knob-mounted power led! (thats sounds wrong!
	

	
	
		
		

		
		
	


	




) 
 But that isnt going to plan, as the knob i drilled the hole in doesnt actually fit on a Alps Blue. So im gonna have to try with a different knob...

 Then just gotta solder everything up when I have some time, and it should be complete!

 Amit_

 

Hi Amit,

 I haven't got around to ordering as yet. I've got a couple of 220uF Jamicon NP caps which I'll send you in the meantime can you PM with your details... forget about paypal, the caps are not expensive items. 

 I don't know if you managed to source suitable heatsinks for IC1 and IC2 but I got some clip on ones from Maplin and they are a "perfect" fit and it's like they were specially made for the WNA.... they're not fancy looking but they do the job and the fact you can clip them on makes life very easy! order code: KU50 price 33p each. Heatsinks are not absolutely necessary as David has measured the working temp of the transistors at 60c but they help dissipate the heat from the transistors 

 Pics of the heatsinks in action 
	

	
	
		
		

		
		
	


	



















 EDIT: the knob you are looking for is 6mm - 6.35 mm or thereabouts (pot shaft diameter)


----------



## Alick

Nice wee heatsinks. I notice you've removed the Nitais and fitted ALCAPs. Big difference? I also notice that it looks like 470uF ALCAPs would be a _very_ tight fit...


----------



## damitamit

Thanks Mike! will PM you the details.

  Quote:


  Originally Posted by * PinkFloyd* 
_EDIT: the knob you are looking for is 6mm - 6.35 mm or thereabouts (pot shaft diameter)_

 

I've found another knob in my parts box that uses a grub screw and will fit (the others were for D shape shafts). Just need to make the LED hole. Im loving the idea of a led on the knob, but I shall see what it turns out in reality very soon!

 Amit


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Nice wee heatsinks. I notice you've removed the Nitais and fitted ALCAPs. Big difference? I also notice that it looks like 470uF ALCAPs would be a very tight fit..._

 

That's a pretty loose fit and finish but I'm happy with the sound so will probably bite the bullet and pot the entire circuit up with melted candle wax... yes, you see 150uF ALCAPS on board they are more than juicy enough to cope with the HD-600's and K-501's ...... even sound the cats whiskers with a 32 ohm load.

 There's a noticeable _difference_ between the ALCAP and Nitai "for sure" but it all boils down to what kind of sound you prefer..... my ears have always favoured the ALCAP sound, whether it be in a loudspeaker or an amp, I've never liked the rubbery sound of polyprops but the vast majority of listeners swear by polyprops and will accept nothing else..... it's totally a matter of what suits your ears 
	

	
	
		
		

		
		
	


	




 To each his own, whatever sounds best to your ears is best and the beauty of DIY is you can tune the amp to your own ears 
	

	
	
		
		

		
		
	


	





 All the best.

 Mike.


----------



## PinkFloyd

I don't know if this will interest any of you guys building the WNA but I've been having a good old listen to it with and without crossfeed and I really do think it would benefit from having a bypassable crossfeed incorporated into it... It sounds great without crossfeed but it also sounds superb with crossfeed! It throws the sound slightly forward from your head making for a lot more natural soundstage (more conventional like speakers) and a much more relaxing fatigue free listen, especially if you listen for hours, it's also particularly good with extreme stereo recordings such as some of the early Beatles efforts. The meier bass enhanced circuit really does pair up very well with the WNA and there is no insertion loss whatsoever, not even a slight drop in volume with the crossfeed in circuit...... I've experienced this crossfeed with many different amps and the WNA / meier combo is spot on 

 It's easy to fit crossfeed into the WNA and will, quite literally, cost no more than a few quid to implement... the most expensive part being the 4 pole "on off on" switch which I've yet been unable to source 
	

	
	
		
		

		
		
	


	




 if anyone knows a UK supplier that sells them then please let me know...... the smaller the size the better!

 I put together a crossfeed on some veroboard and you can see it sitting on top of the two large blue input caps in the following picture (not connected it's just there for demonstration purposes) I have ordered up some smaller resistors and reckon I can get the size of the crossfeed board down to less than half of the one pictured:





 board pictured on the 2 input caps





 Should be easy to reduce the size of the crossfeed circuit by half

 There's just enough room for a 4 pole switch in the WNA kit (between the head-out socket and potentiometer) and there's definitely bags of room to incorporate the crossfeed circuit.. so there's no real reason _not_ to fit a crossfeed into the circuit 
	

	
	
		
		

		
		
	


	




 I've heard rumours on the grapevine that the geezer with the red suit and white beard (no, not Dr. White!) may drop a 6 mega pixel camera down my chimney next month so I'll be able to provide some, hopefully, VERY clear pictures along with instructions on how to incorporate the crossfeed into the WNA 
	

	
	
		
		

		
		
	


	




 In the meantime there's this pretty ropey guide (bad picture quality) or this  one which has _slightly_ clearer images.... 

 If you can source a suitably sized 4 pole switch then connect it thus: 






 Building the crossfeed and fitting the switch and crossfeed into the WNA should take no more than 1 hour and cost no more than £5

 It's gotta be worth doing as you've got all the quality of the WNA along with the added advantage of crossfeed should you ever need it 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## StevieDvd

Interesting as I was listening to 2 new CD's last night and thought they were a bit too left only/right only in places and could do with a bit of crossfeed.

 I'd sat down to try hearing the differences between the HD600s and HD650s so used a jack splitter. I can now definitely hear more bass from the 650s and can use a lower volume, the 600s sound a little flatter if that makes sense. For A/B testing I tried to switch the phones over at repetetive but detailed sections of tracks.

 Went past the newly opened Richer Sounds store in Houndsditch (City of London) and spotted a 3 way rca control. So now I'll be able to switch between the source direct and source via DAC as well.

 Whilst I'm doing all that I can also try one the crossfeeds I made up from your diy guide (my first real electronics project - aaaah).

 The list of jobs is getting smaller - albeit slowly. Mainly because like tonight I'm still at work!


----------



## StevieDvd

I'll post this here mainly as it's such a fountain of info.

 Can you recommend cabling for a very short interconnect. The DAC is in a hammond case sitting on top of the WNA hammond case so the distance between the rca's is very short and a thick cable tends to lift the DAC. I suppose what I need is something like a Cat5 cabled interconnect.

 Suggestions please?

 PS Is there a check via a DMM other than continuity that one should do for rca interconnects?


----------



## Alick

Mike - I'm probably being a bit slow tonight (I usually am by Thursday) but do you really need 4-pole on-off-on, or just on-on? If the former, this is the best I could come up with, but £30 minimum order 
	

	
	
		
		

		
			





 . If the latter, then how about 316-995 ?


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Interesting as I was listening to 2 new CD's last night and thought they were a bit too left only/right only in places and could do with a bit of crossfeed.

 I'd sat down to try hearing the differences between the HD600s and HD650s so used a jack splitter. I can now definitely hear more bass from the 650s and can use a lower volume, the 600s sound a little flatter if that makes sense. For A/B testing I tried to switch the phones over at repetetive but detailed sections of tracks.

 Went past the newly opened Richer Sounds store in Houndsditch (City of London) and spotted a 3 way rca control. So now I'll be able to switch between the source direct and source via DAC as well.

 Whilst I'm doing all that I can also try one the crossfeeds I made up from your diy guide (my first real electronics project - aaaah).

 The list of jobs is getting smaller - albeit slowly. Mainly because like tonight I'm still at work!_

 

Of course, you built a crossfeed a while back Steve..... have a listen to it connected to the WNA and think of that "option" available at the flick of a switch without all the hassle of extra interconnects etc. If you'd like more noticeable crossfeed (the medium level is subtle) then you can do the following:

 replace 200nF cap with a 100nF cap
 replace 47nF cap with a 22nF cap
 replace 2k resistor with a 5k resistor

 Leave the 330R and 2K2 resistors in position

 That will throw the sound a few more inches out of your head


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Of course, you built a crossfeed a while back Steve..... have a listen to it connected to the WNA and think of that "option" available at the flick of a switch without all the hassle of extra interconnects etc. If you'd like more noticeable crossfeed (the medium level is subtle) then you can do the following:

 replace 200nF cap with a 100nF cap
 replace 47nF cap with a 22nF cap
 replace 2k resistor with a 5k resistor

 Leave the 330R and 2K2 resistors in position

 That will throw the sound a few more inches out of your head 
	

	
	
		
		

		
		
	


	


_

 

Just got home and had late dinner so will be settling down to a CD session to allow digestion to take its course.

 Will have some spare time over the next week so perhaps crossfeed number 3 will come to life with the above components. Will watch out for updates on what switch to get and where.

 Ta


----------



## Alick

Quote:


 Mike - I'm probably being a bit slow tonight (I usually am by Thursday) but do you really need 4-pole on-off-on, or just on-on? If the former, this is the best I could come up with, but £30 minimum order . If the latter, then how about 316-995 ? 
 

Or how about this? No minimum order value, but £6 p&p for orders under £30 and the minimum order quantity for the switch is 3. Delivery's free above that.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Or how about this? No minimum order value, but £6 p&p for orders under £30 and the minimum order quantity for the switch is 3. Delivery's free above that._

 

Cheers Alick,

 I saw the mainline switches a while back and it _is_ actually "on on" I'm looking for, dunno where I came up with on off on 
	

	
	
		
		

		
		
	


	




 The one at JPR looks great.... the 4PDT (pt no: 800-248) I may well go for that one it's the right size too !!

 Thanks Alick


----------



## boodi

Quote:


  Originally Posted by *PinkFloyd* 
_replace 200nF cap with a 100nF cap
 replace 47nF cap with a 22nF cap
 replace 2k resistor with a 5k resistor

 Leave the 330R and 2K2 resistors in position

 That will throw the sound a few more inches out of your head 
	

	
	
		
		

		
		
	


	


_

 

Hi Pinky 

 ( I'm a diy noob , you know ..so ) 

 Could you explain why this mods ( caps and resistors ) are going to throw the sound out of your head so are goping to affect soundstage ?

 and also what kind of components do affect the bass presence ( more / less beefy bass ) ?
 thanks


----------



## Alick

Quote:


 The one at JPR looks great.... the 4PDT (pt no: 800-248) I may well go for that one it's the right size too !! 
 

Remember the £30 minimum order though...


----------



## damitamit

Finally built up the WNA (thanks for the caps pinky!)

 slight problem thou. Nothing happens. Switch it on and there no sound.

 The desktop psu is working, checked that. And I think i've wired everything right. But im sure it will turn out to be something silly as I only had 4 hours sleep last nite...

 hmmmmmmmmmmmmmmmmmmmmm


----------



## damitamit

doh! it might help if i solder jumpers to fill J4, J3 and J2! 
	

	
	
		
		

		
		
	


	




 be back in a couple mins...


----------



## PinkFloyd

wire links or zero ohm resistors across all the J positions (jumpers) will help yes


----------



## damitamit

also had a wrongly connected power plug.

 Now i get sound! but i also get a high pitch whine. Is that to do with the output caps?


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_also had a wrongly connected power plug.

 Now i get sound! but i also get a high pitch whine. Is that to do with the output caps?_

 

No.......... that's oscillation.... turn the amp off and double check things. If you've fitted the Jamicons then fit the Nitai as the Jamicons are 6.3V (sorry just realised mistook them for 63V) the Nitai caps are better suited.


----------



## damitamit

Hi Mike, 

 I used the Nitais. I will double check everything and see..


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_Hi Mike, 

 I used the Nitais. I will double check everything and see.._

 

double check you have the diodes and transistors the right way around and triple check you've wired the pot / headout correctly....... whatever it is causing the oscillation will be something silly like a wire in the wrong place....


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_also had a wrongly connected power plug.
_

 


 You didn't connect the amp up with reverse polarity? if so you may have wiped out a couple of LM6171's.


----------



## damitamit

Quote:


  Originally Posted by *PinkFloyd* 
_You didn't connect the amp up with reverse polarity? if so you may have wiped out a couple of LM6171's._

 

Nope, figured out the dc socket tabs with my multimeter and then connected the wires accordinly. Also made sure the psu plub was set to center tip positive.

 What i meant by wrong way in the previous post is the 3rd tab. Didnt seem to connect with the outer plug before, but now it seems to be ok. 2 of the tabs are the same.


----------



## Bassivus

Finally all the parts have arrived
	

	
	
		
		

		
			





 I began by making the PSU first (didn’t want to make the amp first and than have to wait until I make PSU)






 It is the cased Power One open frame 24V 0.5A

 I hope I’ll begin working on the amp itself tomorrow…


----------



## damitamit

wooooooo! it works!! no oscillation

 re-soldered all the pot connections - no luck. still high pitched whistle.
 re-wired all the pot connections with normal wire instead of my pure silver teflon coated stuff - no luck

 replaced the psu electrolytics with the elna cerafines Pinky sent me - it works!!!!

 Im not sure why the differing caps made it stop oscillating? The caps in there originally were the ones that came with the kit.

 Now im gonna have to re-solder all the silver wire back in! Just to know I have silver wire in there. 
	

	
	
		
		

		
		
	


	




 So now im listening with my sony discman and HD600s. sounds sweet! 
	

	
	
		
		

		
		
	


	




 Gona case it up and listen to it with my main rig in a bit maybe. Boy im tired. its 4 am.


----------



## Alick

Well done! Believe me, your amp will get better and better with burn-in. Seems like those LM6171s are temperamental little beggars though.

 I dug out a CD last night which I haven't listened to for a while (possibly pre-WNA); Carol Laula's live album "Naked". It was another revelation. Where as before I thought it was a bloody good album, now it's like I'm at the gig. There are little (and some not so little) things I've just never heard (or noticed) before. Backing vocals, two guitars where before I heard one, crowd noises, little instrumental flourishes. The things I did know from before before had a finesse and life they never previously had. Amazing.


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_wooooooo! it works!! no oscillation_

 

Excellent!


  Quote:


  Originally Posted by *damitamit* 
_replaced the psu electrolytics with the elna cerafines Pinky sent me - it works!!!!_

 

Now that is true twighlight zone stuff, exactly the same thing happened with me on my first WNA but it was the Oscon caps that were the culprit.. I replaced them with bog standard electrolytics and bob's your uncle the oscillation disappeared 
	

	
	
		
		

		
		
	


	




 I tried the rubycons that David supplies with the kit and they were fine in mine... Alick is right the LM6171 can be a temperamental little git at times 
	

	
	
		
		

		
		
	


	




 It "could" be that there was a dry joint or something causing the oscillation and replacing the rubycons with the cerafines cured it... you never know just another one of these annoying gremlins that sometimes appear when you're building a kit.

  Quote:


  Originally Posted by *damitamit* 
_Now im gonna have to re-solder all the silver wire back in! Just to know I have silver wire in there. 
	

	
	
		
		

		
		
	


	


_

 

Take your time and don't do it when you're tired


----------



## boodi

Quote:


  Originally Posted by *boodi* 
_( I'm a diy noob , you know ..so ) 

 Could you explain why this mods ( caps and resistors ) are going to throw the sound out of your head so are goping to affect soundstage ?

 and also what kind of components do affect the bass presence ( more / less beefy bass ) ?
 thanks_

 

Hi Alick 

 ..maybe you could briefly answer to my questions ?

 Thanks


----------



## PinkFloyd

Quote:


  Originally Posted by *boodi* 
_Hi Pinky 

 ( I'm a diy noob , you know ..so ) 

 Could you explain why this mods ( caps and resistors ) are going to throw the sound out of your head so are goping to affect soundstage ?

 and also what kind of components do affect the bass presence ( more / less beefy bass ) ?
 thanks_

 

Hi Boodi,

 The caps and resistors refer to an add on crossfeed and are not part of the amp. To learn about crossfeed have a look here


----------



## Alick

Boodi

 Pink Floyd's link to the Jan Meier page should answer all your questions. For me, it's about allowing sound to 'leak' from one channel to another (as it would with speakers in a room) to present a more 'natural' sound-stage. Most (if not all) albums are engineered to be listened to through speakers, not headphones which provide almost total isolation of the two stereo channels. This isn't how albums are meant to be heard and it can be quite strange on some very separated albums, particularly early stereo recordings.

 Having said all this, I haven't tried a crossfeed yet, but I intend to build and try one soon.


----------



## StevieDvd

Crossfeed

 Not exacty a scientific answer but I bought Jean-Michele-Jarre Aero CD/DVD and Tubular Bells 3 the other day. When listening on headphones certain tracks just sounded too severe with the sound from only one channel at a time. At the time I thought must try the crossfeed I built from Pinkfloyds web page. Then I came back to this thread and crossfeed had come up. I put the crossfeed in and tried to find the tracks which I'd thought were too severe, couldn't find them (that is until I took the crossfeed out).

 I use crossfeed with Foobar2000 on my PC all the time and perhaps a switchable one on the WNA is now the next diy thing for me.


----------



## j4100

Hi Guys,

 I'm new here and was directed to Head-Fi by some kind chap on PFM. I have recently bought a set of Beyer DT-150's and really need to give them something better than the Yamaha tape deck they currently use. I'm also new to soldering, but I'm an engineer and have no problems trying new stuff. Besides, that soldering station I bought would look silly sitting around doing nothing!

 I have posted on this thread because after a bit of research, here, and on other Forums (Fora?), I have decided to build the WNAHA. I have also noticed just how much information is on this massive thread, and so to short-cut things, I'm asking if any of you can recommend what I should do, over and above what is in the kit (I was going to just buy the "audiophile" kit). You know, wiring, components, anything within reason. 

 I have also briefly read about the crossfeed, and would like to add that in. That sounds like a great idea, I would love to hear that. Also, is the wall wart ideal, or would you recommend a seperate PSU (possibly in matching case? - much better looking).

 I will read this thread through before starting, but I know that you can set me right for the start. I respect the knowledge on here, and PinkFloyd for starting this one off, and so, would appreciate any help / direction you want to give. 

 Many thanks


----------



## Alick

I think you might possibly want to consider the "complete" kit rather than the "audiophile" kit; it seems to be a better buy. The complete kit (which Pink Floyd has just built) comes with everything you need for £150. It's not on the WNA site yet but I'm sure Dr White will happily provide details if you email him. ISTR that the audiophile kit comes with a stepped attenuator, but no case, knob, connectors, hook-up wire or indicator. 

 I haven't tried any PSU other than the wall wart, but I think Pinky did and didn't notice too much of a difference.


----------



## PinkFloyd

Quote:


  Originally Posted by *j4100* 
_Hi Guys,_

 

Hi j4100 welcome to Head-Fi 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *j4100* 
_I'm new here and was directed to Head-Fi by some kind chap on PFM. I have recently bought a set of Beyer DT-150's and really need to give them something better than the Yamaha tape deck they currently use. I'm also new to soldering, but I'm an engineer and have no problems trying new stuff. Besides, that soldering station I bought would look silly sitting around doing nothing!_

 

From all accounts the WNA is a great match with Beyer headphones, Dr. White uses Beyer phones (as well as Senn's AKg's and Grado) and reckons the WNA is very well suited to the Beyer phones. You should be ok with the soldering but it's probably best to hone your soldering skills on an old PCB (available from any skip in the uk 
	

	
	
		
		

		
		
	


	




 ) before going to work on the WNA.

  Quote:


  Originally Posted by *j4100* 
_I have posted on this thread because after a bit of research, here, and on other Forums (Fora?), I have decided to build the WNAHA. I have also noticed just how much information is on this massive thread, and so to short-cut things, I'm asking if any of you can recommend what I should do, over and above what is in the kit (I was going to just buy the "audiophile" kit). You know, wiring, components, anything within reason._

 

The kit, generally, contains the best possible parts you can lay your hands on (unless you want to get into crazy boutique component territory) RC55Y Welwyn resistors, ALPS blue velvet pot, gold plated phono sockets etc....

 The only parts of the kit you may wish to upgrade at a later date are the NITAI output caps, the decoupling caps and the enclosure which is utilitarian and very 80's hairshirt.... if aesthetics don't bother you then the enclosure is up to the job and houses everything in an unassuming, plain but practical fashion. The under the bonnet "sound making" components are top class and the only components you _may_ wish to "tune" to your own taste are the capacitors..... no other tweaks are necessary as Dr. White has optimised the circuit around the LM6171 opamps. 

  Quote:


  Originally Posted by *j4100* 
_I have also briefly read about the crossfeed, and would like to add that in. That sounds like a great idea, I would love to hear that. Also, is the wall wart ideal, or would you recommend a seperate PSU (possibly in matching case? - much better looking)._

 

Crossfeed can be handy and it's easy (and cheap) to incorporate into the WNA so there's no reason not to add it whilst your at it..... I'm awaiting my new camera and will post a step by step pictorial (very easy to follow) as soon as the camera arrives 

 Some say the wallwart is ideal others report great improvements from using linear / regulated PSU's ..... a fellow Head-Fier "captain" is using the WNA cascode PSU with his amp and he reports an "amazing improvement" to the sound (maybe you'd like to share your thoughts Kirk?) I went from the standard wart to a Calex open frame linear PSU and couldn't hear any "immediate" improvement but I must confess, a few months down the line, that if I go back to the wart after the linear PSU I detect a very slight haziness compared with the linear PSU..... the law of diminishing returns kicks in and a £200 PSU will not sound £190 better than a £10 wart but there is an improvement albeit a very slight improvement. I really must get a shot of the cascode PSU.... I've heard nothing but good things about it 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *j4100* 
_I will read this thread through before starting, but I know that you can set me right for the start. I respect the knowledge on here, and PinkFloyd for starting this one off, and so, would appreciate any help / direction you want to give._

 

The WNA manual has been updated and now reflects all the mods that this thread helped spur on Dr. White to implement so there's no need to trawl through the entire thread. The manual incorporates everything in a simple, easy to follow way (as easy as painting by numbers) and thanks must go out to Dr. White for taking the time to listen to our requirements and spending so much of his time and expertise improving his design to meet our requirements...... nice one.


----------



## j4100

Hey thanks for the quick reply!

  Quote:


 You should be ok with the soldering but it's probably best to hone your soldering skills on an old PCB (available from any skip in the uk 
	

	
	
		
		

		
		
	


	




 ) before going to work on the WNA. 
 

Ha-ha! You're right, of course. I'm sure I can find something to butcher 
	

	
	
		
		

		
		
	


	




 Thanks for the condensed version of this thread. Good to hear about the updated kit and manual. I think I will build a stock version, perhaps in a different casing, as there's a lot of good ones available.

 Having seen your website and your Chiarra with PSU in a single case, I was thinking along these lines about the WNAHA and a PSU in one case. However, I will probably not bother at this point.

 Thanks again for your reply, I will keep an eye on this forum, and your site for the crossfeed info. Keep up the good work!

 I guess the next step is to put an order in with the good Dr. 





 Cheers,
 rod


----------



## Captain

Quote:


  Originally Posted by *PinkFloyd* 
_soon as the camera arrives 

 Some say the wallwart is ideal others report great improvements from using linear / regulated PSU's ..... a fellow Head-Fier "captain" is using the WNA cascode PSU with his amp and he reports an "amazing improvement" to the sound (maybe you'd like to share your thoughts Kirk?)_

 


 I think that the WNA Cacode is a better option then the wallwart, seems to open the sound up more - becomes less compressed. Also better separation of instruments and vocals. I think having screened cabling helps it along. As you have said though Mike its not 20 times better in price ratio


----------



## Captain

Quote:


  Originally Posted by *Alick* 
_the audiophile kit comes with a stepped attenuator._

 

Excuse my ignorance, but what's a stepped attenuator and what dose it do?


----------



## Madcat05

an SA is a volume contol that moves in steps, each step usually increases by 3 dB.

 An SA uses resistors to set if it's 50K, or 100K etc.

 This is an SA


----------



## j4100

Hi Alick,
 The price list currently available from the website has the audiophile kit coming in above the standard kit, so I thought that it would have had everything. I will call prior to ordering, so thanks for the info.

 rod


----------



## Alick

The price list is not up to date. It lists two versions using either OPA134 (standard) or OPA627 (audiophile) op-amps with the audiophile version using higher quality passive components. The new version is a more comprehensive kit with everything you need including cable and case (the previous versions didn't), LM6171 op-amps and high quality passives. I believe the price is £150 which is a steal.


----------



## j4100

Hi Alick,

 Thanks for that. That sounds about right 
	

	
	
		
		

		
		
	


	




 Another question. Other kit builders often replace the supplied wire, as this would be a pain to change once the kit is built. Is the supplied wire in this kit fine for the job, or would you recommend getting something else?

 Cheers,
 rod


----------



## Alick

I'm probably the wrong person to ask as I just bought the PCB from WNA and sourced the rest of the kit myself, so I haven't used the wire that WNA provide. However, if the current kit had been available at the time, I'd have bought it without hesitation. 

 I am seriously thinking about buying the cable from WNA and rewiring my amp though. The photo's Mike published in this thread show that the supplied wire makes for a very neat wiring job. The spec' for the cable is very good and as everything else Dr White provides is of the highest quality, I would expect no less of the supplied cable. I doubt if you'll find anything significantly better.


----------



## j4100

Thanks again Alick. I will refrain from asking any more daft questions about this kit (maybe!), and just order it! Thanks to you both for you help.

 Cheers,
 rod


----------



## Alick

No problem and don't hesitate to ask any questions you might have. We all do; that's why this thread is so long. 
	

	
	
		
		

		
		
	


	




 Good luck with the kit. I'm sure you'll be chuffed with it.


----------



## PinkFloyd

Quote:


  Originally Posted by *j4100* 
_Hi Alick,

 Thanks for that. That sounds about right 
	

	
	
		
		

		
		
	


	




 Another question. Other kit builders often replace the supplied wire, as this would be a pain to change once the kit is built. Is the supplied wire in this kit fine for the job, or would you recommend getting something else?

 Cheers,
 rod_

 

Hi Rod,

 The supplied coax is very good quality and silver plated... you can hold a soldering iron on it for 10 minutes and it won't melt, very good stuff to work with indeed 

 Mike.


----------



## j4100

Hi Mike,

 I've sent the Dr an e-mail for details, so here goes... into the wild and wacky world of DIY amps *AND* headphones... and it's all *YOUR* fault 
	

	
	
		
		

		
		
	


	




 Cheers,
 rod


----------



## StevieDvd

I think at this rate Scotland will have the highest WNA per capita in the world


----------



## Alick

Considering that WNA is based in Glasgow, I guess Dr White's stock will tend to up our average...


----------



## Bassivus

Finally I managed to finish the amp. But the oscillation gremlins visited me too. After reading recent info about oscillation
  Quote:


  Originally Posted by *PinkFloyd* 
_
 ...Now that is true twighlight zone stuff, exactly the same thing happened with me on my first WNA but it was the Oscon caps that were the culprit.. I replaced them with bog standard electrolytics and bob's your uncle the oscillation disappeared 
	

	
	
		
		

		
		
	


	




 I tried the rubycons that David supplies with the kit and they were fine in mine... Alick is right the LM6171 can be a temperamental little git at times 
	

	
	
		
		

		
		
	


	




 It "could" be that there was a dry joint or something causing the oscillation and replacing the rubycons with the cerafines cured it... you never know just another one of these annoying gremlins that sometimes appear when you're building a kit..._

 

I thought to give a try to my pair of Os-cons. Fired the Amp and the high pitched whine was noticeable. All else seems to be fine. Replaced the Os-cons with Rubicon ZA-s but the whine-oscillation is still there!?!? Tried several sets of output caps – nothing changed… 
 I remember reading on this thread Pink quoting Dr.White about suggesting caps between the opamp V+- and ground. As I understand it should be the ceramic 100nf 
	

	
	
		
		

		
		
	


	




and between op 4 and 7 0.1uF or 1uF film cap
	

	
	
		
		

		
		
	


	




? Since I would like to try this to cure the oscillation but I’m not sure if I understand this right, could someone PLEASE explain how this should be done? Since I have the LM6171 on all positions should it be done on all three pos.?

 Ivica


----------



## PinkFloyd

Quote:


  Originally Posted by *Bassivus* 
_Finally I managed to finish the amp. But the oscillation gremlins visited me too. After reading recent info about oscillation_

 







  Quote:


  Originally Posted by *Bassivus* 
_I remember reading on this thread Pink quoting Dr.White about suggesting caps between the opamp V+- and ground. As I understand it should be the ceramic 100nf 
	

	
	
		
		

		
		
	


	




and between op 4 and 7 0.1 uF film cap
	

	
	
		
		

		
		
	


	




? Since I would like to try this to cure the oscillation but I’m not sure if I understand this right, could someone PLEASE explain how this should be done? Since I have the LM6171 on all positions should it be done on all three pos.?

 Ivica_

 

Ivica,

 I wouldn't worry about fitting these additional caps at this stage, there should be NO oscillation at all and it's best if you find out what's causing the LM6171's to oscillate.

 Double check all connections and inspect the solder joints under the board with close scrutiny. are you using shielded hook up wire? if not then ensure that you twist unshielded cable... long lengths of unshielded wire _can_ induce oscillation. Have you fitted input caps? if not try fitting some, this may also be a contributing factor depending on your source. check and then double check that all the components are fitted with correct orientation and that the correct values of resistors are fitted, it will be something very simple causing the oscillation but it may prove a bugger to find out what it is! have you got the incandescent lamps fitted? I substituted them with a 25R resistor and it caused the LM6171 to oscillate like crazy so that's another thing to look out for.. 

 Basically if you stick to the kit plan and fit everything as instructed there should be no problems whatsoever... have you replaced *R4* (220R) with a zero ohm link?? If not the LM6171 will oscillate. *R4* _must_ be fitted with a wire link or zero ohm resistor and not a 220 ohm resistor.

 Also R6 should be a 75 ohm resistor and not 120 ohm. 

 It's also _Essential_ that you fit dummy load resistors to the headphone socket.. anything between 30R - 300R will be fine.







 Also ensure that I2 is a 5.6mA CRD and I1 is a 3.5mA CRD.

 Check these obvious things and see how you get on 

 All the best.

 Mike.


----------



## Bassivus

Mike,

 Thanks for detailed reply!!! I'll print it and use it as check list. Will report my findings later...


----------



## PinkFloyd

Quote:


  Originally Posted by *Bassivus* 
_Mike,

 Thanks for detailed reply!!! I'll print it and use it as check list. Will report my findings later..._

 

No probs hope you get to the bottom of it. Another thing worth checking are the diodes and CRD's, ensure they are in the right way round... also check that the metal side of the transistors match up with the thick white lines on the board. (note that tr3 and tr4 go in different directions)

 High res pic HERE

 Mike.


----------



## PinkFloyd

Had a word with David regarding the occasional oscillating amps and he's of the opinion it could possibly be something to do with R4 and he recommends trying a wire ended ferrite bead in place of a zero ohm link in R4.

 There was a WNA at the New York meet and it was picking up rf from the Empire State building causing the LM6171 to oscillate like crazy so if you're experiencing this previously unexplained oscillation then it may be a very good idea to fit wire ended ferrite beads instead of the jumpers in R4, the ferrite beads will short out any radio frequency interference. It may be worth doing this as standard when building a kit, it'll make the amp rfi proof. It might also be worth threading ferrite tube beads on the input signal and power leads where they join the connectors inside the case.

 I trust David will be supplying wire ended ferrite beads with future kits instead of the zero ohm links for R4, this will ensure that amps that reside in areas where there is a high level of rfi won't experience this random oscillation phenomenon that has cropped up in a few of the kits.... the wire ended ferrite beads won't affect the sound quality as they are simply zero ohm links with ferrite beads wrapped around them, I suppose you could also fit wire ended ferrite beads in _all_ the jumper positions...... wouldn't do any harm 
	

	
	
		
		

		
			





 EDIT: if you don't have any wire ended ferrite beads then small ferrite beads will do the same job, just feed a wire link through the gap in the ferrite bead and solder the wire into position at R4.... job done.


----------



## Bassivus

Here is my WNA:






 I went double checking all Mike listed and did not find any mistakes. I have the input caps fitted, also the dummy load resistors and all the jumpers are in place. Wire I have used is Van den Hul CS 18 – silver plated OFCopper. It is not shielded but I surely twisted it 
	

	
	
		
		

		
		
	


	




 Tried it for a moment connected to my CD player and it was working – besides the oscillation. I believe it is enough of the proof that all the parts are in place… THEN… one of the many times turning the power on and off - oscillation just stopped! Turned it off and on one more time and there it was again… HMMM …Tapped the front plate and found it turns the whine on and off. Explored further in that direction and finally came to conclusion that the problem is in the power switch! When I bypassed the switch all was fine!!! Rewired the switch all over again just to make sure that the problem was not in bad soldering job, but the oscillation occurred again and tapping was not helping any more 
	

	
	
		
		

		
		
	


	




 I was too tired to try replacing the switch with the new one and left that for tomorrow. But I could not help trying to touch connect 0.1uF MKP bypass cap across the pins 4 and 7 in rail splitter and it stops the oscillation!!! Tomorrow I will try to change that switch and see if the new one will cure the problem.


----------



## PinkFloyd

Quote:


  Originally Posted by *Bassivus* 
_
 I went double checking all Mike listed and did not find any mistakes. I have the input caps fitted, also the dummy load resistors and all the jumpers are in place. Wire I have used is Van den Hul CS 18 – silver plated OFCopper. It is not shielded but I surely twisted it 
	

	
	
		
		

		
		
	


	




 Tried it for a moment connected to my CD player and it was working – besides the oscillation. I believe it is enough of the proof that all the parts are in place… THEN… one of the many times turning the power on and off - oscillation just stopped! Turned it off and on one more time and there it was again… HMMM …Tapped the front plate and found it turns the whine on and off. Explored further in that direction and finally came to conclusion that the problem is in the power switch! When I bypassed the switch all was fine!!! Rewired the switch all over again just to make sure that the problem was not in bad soldering job, but the oscillation occurred again and tapping was not helping any more 
	

	
	
		
		

		
		
	


	




 I was too tired to try replacing the switch with the new one and left that for tomorrow. But I could not help trying to touch connect 0.1uF MKP bypass cap across the pins 4 and 7 in rail splitter and it stops the oscillation!!! Tomorrow I will try to change that switch and see if the new one will cure the problem._

 

Aha, I had one amp like that and it would whine and hum like mad and as soon as I touched the case the whine and hum stopped.. pretty weird stuff 
	

	
	
		
		

		
		
	


	




 If this continues I reckon it'll be necessary to fit wire ended ferrite beads in R4 I found some here you could also fit beads on the inputs (mains and signal)


----------



## Bassivus

Weird stuff continues. Today I desoldered the power switch and connected the DC wires together with LED only without power switch – oscillating. Disconnected the LED – not oscillating. Did it at least three more times to make sure, and concluded that I found the fault. Hooked all back up on the switch, only this time without the LED and before soldering tried it once more – NO OSCILLATION. Soldered it VERY carefully up, fired it and found that once again it IS OSCILLATING. I know I’m no soldering master but I don’t believe I would make the same mistake on same place three times!!!
 In the mean time I have read the info about ferrite beads and will try it, but now after all this trouble I have doubt in my mains wires. For audio signal I have used VDH wire but for DC I used twisted pairs from CAT5 UTP cable. I have already used this kind of wire in other jobs and it never caused me a problem but I’m considering may it be the voodoo behind all this. Maybe two pairs of twisted isolated wire is not good for the LM6171???


----------



## PinkFloyd

Quote:


  Originally Posted by *Bassivus* 
_Weird stuff continues. Today I desoldered the power switch and connected the DC wires together with LED only without power switch – oscillating. Disconnected the LED – not oscillating. Did it at least three more times to make sure, and concluded that I found the fault. Hooked all back up on the switch, only this time without the LED and before soldering tried it once more – NO OSCILLATION. Soldered it VERY carefully up, fired it and found that once again it IS OSCILLATING. I know I’m no soldering master but I don’t believe I would make the same mistake on same place three times!!!
 In the mean time I have read the info about ferrite beads and will try it, but now after all this trouble I have doubt in my mains wires. For audio signal I have used VDH wire but for DC I used twisted pairs from CAT5 UTP cable. I have already used this kind of wire in other jobs and it never caused me a problem but I’m considering may it be the voodoo behind all this. Maybe two pairs of twisted isolated wire is not good for the LM6171???_

 

I know what your experiencing and I know how you're feeling... getting to the stage you want to tear your hair out by the roots.... I experienced exactly the same phenomenon with one of the WNA's I made and it almost drove me mad trying to figure out what was going down......

 You've got a heck of a load of wires there and they are splaying about in free space and are not inside a shielded enclosure so you may be experiencing oscillation problems by the long lead lengths acting as small antennas and picking up radio frequency interference.

 In this instance the ferrite beads are definitely the way to go and you may also want to line the plastic ends of the enclosure with sticky backed aluminium foil.. this will help shield from rfi also.... the fact that this is coming and going strongly suggests its rfi and I'm 90% certain that once you case the circuit up / tidy the wiring and fit the ferrite beads you'll experience no oscillation whatsoever..... I wouldn't mess about disconnecting anything else as you'll just be going around in circles and will end up bashing your head off a brick wall.... ferrite beads / shielded enclosure I'm pretty certain that will do the trick 
	

	
	
		
		

		
		
	


	




 All the best

 Mike.


----------



## jnewman

Well, after putting mine in its enclosure, I couldn't get it to work (no sound out at all), and today's the first time I've really had time to take a good look at it. It turns out I somehow managed to fry the power supply transistors, and they're shorting the power rails to ground - take them out, and the resistances go back to what they ought to (in the kohm range increasing as the caps fill). So now I have to wait till I can get some more transistors - which is a shame, because the WNA destroys the MINT that's the only other thing that I have right now. Once I get it working again, I'll have to get started on my Dynahi boards and maybe a PPA - then when I break one, I'll have backups 
	

	
	
		
		

		
		
	


	




.


----------



## Bassivus

I must have made the _oscillation god_ very angry and now he is giving me a hard time
	

	
	
		
		

		
		
	


	



 Today I bought last 4 pieces of ferrite beads in the local store and fitted them on R4/jumprer place





, and before the power switch. Cased all up, wrapped some aluminium foil but it is still oooscilllllaaaating 
	

	
	
		
		

		
		
	


	




… The only thing that really helps for now is this bypass cap:


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_Well, after putting mine in its enclosure, I couldn't get it to work (no sound out at all), and today's the first time I've really had time to take a good look at it. It turns out I somehow managed to fry the power supply transistors, and they're shorting the power rails to ground - take them out, and the resistances go back to what they ought to (in the kohm range increasing as the caps fill). So now I have to wait till I can get some more transistors - which is a shame, because the WNA destroys the MINT that's the only other thing that I have right now. Once I get it working again, I'll have to get started on my Dynahi boards and maybe a PPA - then when I break one, I'll have backups 
	

	
	
		
		

		
		
	


	




._

 

Did you bolt the phono sockets and uninsulated power connector to a metal case Jimmy?


----------



## PinkFloyd

Quote:


  Originally Posted by *Bassivus* 
_I must have made the oscillation god very angry and now he is giving me a hard time
	

	
	
		
		

		
		
	


	




 Today I bought last 4 pieces of ferrite beads in the local store and fitted them on R4/jumper place and before the power switch. Cased all up, wrapped some aluminium foil but it is still oooscilllllaaaating 
	

	
	
		
		

		
		
	


	




… The only thing that really helps for now is this bypass cap._

 

There's a lot of wire in your amp Bassivus (long thick runs) and this will not be helping the situation.. tell me, if you hover above the amp does the pitch of the frequency fluctuate? I mean move about over the amp and even touch the amp does this alter the pitch? none of the kit amps suffer from this and I can only agree with David that it's possibly the cable layout that's causing it to act as an antenna... it happened with one I built and simply moving some of the wires over to the left got rid of it temporarily.... it returned and I moved the wires again and it disappeared... I ended up replacing all the wiring with shielded cable and the problem disappeared instantly.. the LM6171 is a great op amp but it can be very awkward at times!

 I'm sure David would be interested to experience one of these random oscillating amps first hand to establish exactly what is causing the problem.. that's 3 I've heard of now... yours, one of mine and Damitamit's... and they were all built into Hammond enclosures... Damitamit's oscillation was cured when he replaced the stock 100uF caps with 220uF cerafines (c3 & c5) which makes this even more weird..... I remember the first WNA I built oscillated like mad and I substituted the OSCON caps in c3 & c5 with el cheapo general purpose caps and all was fine 
	

	
	
		
		

		
		
	


	




 Thankfully these instances are very few and far between but it would be good to know the exact cause as I know how frustrating it is spending days fault finding and not finding anything at fault..... drives you round the bend 
	

	
	
		
		

		
		
	


	




 My money would be on the wiring and possibly the type of wire used.. the WNA kit's don't display any of these characteristics and they come supplied with shielded cable.... my oscillating DIY WNA turned out to be due to the unshielded long runs of cable... the OSCON cap oscillation and Damitamit's cap oscillation is still a mystery though...... there's also the possibility that one of the components is faulty, never assume they are all 100% functioning... 

 If you can't get any joy Bassivus then I'm sure Dr. White would be happy to take a look at the amp for you... it would give him the opportunity to witness one of these very rare oscillating amps at first hand and would provide you (and the rest of the WNA builders) with an answer as to what is causing it... 

 All the best.

 Mike.


----------



## Bassivus

Quote:


  Originally Posted by *PinkFloyd* 
_There's a lot of wire in your amp Bassivus (long thick runs) and this will not be helping the situation.._

 

It's has relatively thick insulation but it is 20 AWG wire. And the longest run is from phono inputs to the potentiometer and measures 25cm. But it is not shielded wire…



  Quote:


 tell me, if you hover above the amp does the pitch of the frequency fluctuate? I mean move about over the amp and even touch the amp does this alter the pitch? none of the kit amps suffer from this and I can only agree with David that it's possibly the cable layout that's causing it to act as an antenna... it happened with one I built and simply moving some of the wires over to the left got rid of it temporarily.... it returned and I moved the wires again and it disappeared... I ended up replacing all the wiring with shielded cable and the problem disappeared instantly.. the LM6171 is a great op amp but it can be very awkward at times! 
 

I tried moving all the wires, drifting, tapping and besides for short period of time that tapping front plate changed something the only thing that affects the frequency of the buzzing sound is moving the *power wire*. I did not notice any changes when I move audio signal wire. When I leave it on for more than 3,4 seconds Tr3 and Tr4 are getting pretty warm.



  Quote:


 Damitamit's oscillation was cured when he replaced the stock 100uF caps with 220uF cerafines (c3 & c5) which makes this even more weird..... I remember the first WNA I built oscillated like mad and I substituted the OSCON caps in c3 & c5 with el cheapo general purpose caps and all was fine 
	

	
	
		
		

		
		
	


	



 

I’ll try to fit some 220uF/25V on c3&c5 positions as next step…



  Quote:


 Thankfully these instances are very few and far between but it would be good to know the exact cause as I know how frustrating it is spending days fault finding and not finding anything at fault..... drives you round the bend 
	

	
	
		
		

		
		
	


	



 

I’m a very patient man 
	

	
	
		
		

		
		
	


	






  Quote:


 My money would be on the wiring and possibly the type of wire used.. the WNA kit's don't display any of these characteristics and they come supplied with shielded cable.... my oscillating DIY WNA turned out to be due to the unshielded long runs of cable... 
 

It would really make me sad to find that the wire I like so much makes trouble with the WNA LM6171. I just love the way that Van den Hul cable sounds…



  Quote:


 If you can't get any joy Bassivus then I'm sure Dr. White would be happy to take a look at the amp for you... it would give him the opportunity to witness one of these very rare oscillating amps at first hand and would provide you (and the rest of the WNA builders) with an answer as to what is causing it... 
 

Well that is the most generous offer, but like I said I am a very patient man so I’ll try to fix it myself for now 
	

	
	
		
		

		
		
	


	




 . I mean if I were in the UK it would already be on it’s way to Dr. White, but since I live in Serbia it is quite complicated, expensive and dangerous for the contents(bad handling), so I will give some more time before taking the risk…
 But it is comforting to now that if I fail I will have it fixed sometimes 
	

	
	
		
		

		
		
	


	





 All the best 

 Ivica


----------



## jnewman

Quote:


  Originally Posted by *PinkFloyd* 
_Did you bolt the phono sockets and uninsulated power connector to a metal case Jimmy?_

 

No - I haven't been able to figure out why it did it - I guess I accidentally shorted something somewhere else. I actually haven't been able to get to the shop yet, so the panels haven't been milled, so I just mounted all the plugs on two pieces of cardboard so I could at least have it usable and get rid of all the alligator clip connections. The DC jack and switch are both insulated anyway. I've gone over all the wiring a number of times and it's all correct. I'm just going to get some more transistors and see if it won't work - it MIGHT be that the 1000uF rail caps I added draw too much current through the transistors and burn them out, so I'm going to switch back to the 100uF's, put in new transistors, and test, then switch the 1000uF's back in and see if that breaks it (I've ordered plenty of extra transistors). With the 1000uF's, they may need heatsinks for startup even though they don't normally need 'em - I'm just going to have to do some experimenting.

 Thanks for the troubleshooting help, though - that is the sort of thing I'd do and not realize 
	

	
	
		
		

		
		
	


	




.

 My big mistake was doing too much at once - I switched to 1000uF caps, added the DC jack and switch (had been using the jack with alligator clips), added the RCA ins (had been using a 1/8" to alligator clips cable), added the volume pot (had been using a source with a volume control), switched to paralleled output caps (now 20uF), and put it in my case (with, as forementioned, cardboard end panels) all at once with no testing. I know that's a bad practice, but it's something I always do and it always seems to get me in trouble.


----------



## Bassivus

Today I replaced the 100uF/16V Rubycons on C3&C5 position with the 220uF/25V cheap Jamicons and the amp is not oscillating (I hope for good…). I believe now we can say that this problem with the rail caps is becoming a bit symptomatic…
 Today I will finally do some serious listening


----------



## Alick

Interesting; that's the same solution as Mike found when he removed the OSCON's from the same locations. I had bought OSCON's but fitted some alternatives (which I think Mike sent me) just in case. I haven't experienced any oscillation thankfully, only sweet, sweet music.
	

	
	
		
		

		
		
	


	




 Glad you found the solution, now just enjoy your amp...


----------



## PinkFloyd

Quote:


  Originally Posted by *Bassivus* 
_Today I replaced the 100uF/16V Rubycons on C3&C5 position with the 220uF/25V cheap Jamicons and the amp is not oscillating (I hope for good…). I believe now we can say that this problem with the rail caps is becoming a bit symptomatic…
 Today I will finally do some serious listening 
	

	
	
		
		

		
		
	


	


_

 

Congratulations!!!

 Now this is seriously very odd indeed!! I replace the 100uF OSCON caps with el cheapo caps, problem solved...... Damitamit replaces his 100uF caps with 220uF cerafines, problem solved..... you replace your 100uF caps with 220uF Jamicons, problem solved... ho hum.. <whistles twighlight zone music>

 Well, that's solved the oscillating opamp now we have to know _why_ the 100uF cap appears to be rebelling in very few of the circuits... 

 Let us know how you find the sound quality Bassivus and I'm really glad you got to the bottom of things


----------



## 1UP

Hi all, I'm very happy with my WNA. I had had a small problem when I first used mine, a high-pitched whirring noise that came on when powered (no signal being routed, though). It went away when I twiddled the PSU connector on the back. It's not come back since. Is this the same issue? Should I let Dr White know?


----------



## jpmoon

My wna headphone amp only miss-behaved (low level frying noise) at max and min volume levels, no signal but source connected. I fitted the input caps to isolate the opamps DC conditions from the pot - no change. I've used three different types of electrolytic in the rail splitter, always powered from the plug top PSU, no real difference.

 Luckily it REALLY didn't like driving my amp via cheap interconnects (strangely it was quite happy with 1m of unscreened star quad type), and with the cheap cables it didn't like having a big aerial (me) anyway near it.

 Picking up on somebody else's comment - the circuit is trying hard to be a video DA, DC to 5.5MHz. I soldered 100nF polycarbonate caps between pins 4 and 7 IC1 on the track-side and luckily (it's the easiest thing to try) it seems to have cleared up my minor (compared to other's) instability. I didn't bother with the rail splitter opamp, but looking at the distance between it and C4 and C6 I may have to revisit this.

 Further precautions, grounded metal near trackside of pcb to act as ground plane, care with grounding in general, further, I noticed that turned-pin or not the ICs are a lot looser in their sockets now (me fiddling I expect). When I'm finished I'll ditch the sockets.

 Starting to think about switching the output between phones and amp now, without provoking the oscillation god.

 John Moon.


----------



## PinkFloyd

Quote:


  Originally Posted by *1UP* 
_Hi all, I'm very happy with my WNA. I had had a small problem when I first used mine, a high-pitched whirring noise that came on when powered (no signal being routed, though). It went away when I twiddled the PSU connector on the back. It's not come back since. Is this the same issue? Should I let Dr White know?_

 

Doesn't sound like there's anything to worry about especially as the amp is working fine.... did you build the amp yourself or was it prebuilt by WNA?


----------



## Bassivus

Wow!!! After all the trouble I had with the oscillating amp, I can only say it was all well worth it. I am very happy with the sound of the amp. For the first time I have listened loud levels with the headphones for extend period of time, feeling no fatigue. I am so amazed with the sound that I still can not put all this emotion into writing… As it is not yet properly burnt in and I have listened to it only with the Nitai 22uF output caps, there is even a room for improvement…


----------



## Alick

We said it was good!


----------



## StevieDvd

Welcome to Team WNA


----------



## 1UP

Hi Mike, mine was built by WNA themselves - cool guys (I'm useless with a soldering iron and don't know about EE)! Really nice amp! I think I just need to upgrade my headphones now and then I can escape forever from this website.


----------



## PinkFloyd

I was having a scout around yesterday for a message board to add to the DIY section of my website as the crummy thing (zonkboard) I paid $5 dollars for had disappeared off the face of the planet 
	

	
	
		
		

		
		
	


	




 I came across a free ProBoard message board which is now up and running and thought you guys might be interested to learn that Dr. White has agreed to answer WNA headamp specific questions in the "manufacturers question and answers section" 
	

	
	
		
		

		
		
	


	




 His nickname is "Chalky" and he will be more than happy to answer any questions you may have on the WNA however diverse they may be! 

 It may take him a few days to respond but the wait will be worth it as the info will be direct from WNA and not third hand info.

 If you'd like to ask Dr. White a specific question or offer any suggestions then please feel free to ask them here

 I'd like to keep this board as small and intimate as possible and spend maybe 20 minutes per day checking posts etc. I want to keep it specific to the tweaks on my tweaks page and all the other sections such as "The Grotto Lobby" will be removed in due course......

 Ideally the message board will be for WNA / gspaudio / Williams Hart / Musical Fidelity related discussion only..... 

 All the best.

 Mike.


----------



## Alick

Good job Mike. Yet another forum to check every day...


----------



## jnewman

All is well again - with the new transistors I discovered that the 1000uF blackgates I'd put in were making the amp oscillate. A lot. The transistors got to finger-burning temp in seconds. So I assume that I just left it on without listening for a bit after I put in the 1000uF's and the transistors burned out. I'm back to 100uF rail caps now and the amp is back to working and it still sounds great!

 I'm really glad to hear so many people have gotten into building this amp - it's a great one.


----------



## PinkFloyd

Quote:


  Originally Posted by *jnewman* 
_All is well again - with the new transistors I discovered that the 1000uF blackgates I'd put in were making the amp oscillate. A lot. The transistors got to finger-burning temp in seconds. So I assume that I just left it on without listening for a bit after I put in the 1000uF's and the transistors burned out. I'm back to 100uF rail caps now and the amp is back to working and it still sounds great!

 I'm really glad to hear so many people have gotten into building this amp - it's a great one._

 

Excellent Jim,

 I'm glad you managed to get her up and running again... I went as far as 470uF without problems but decided on a happy medium of 220uF..... 100uF OSCONS caused tr3 and tr4 to reach finger burning temperatures in one amp I made (and yes I held my finger on the tranny for 10 seconds and ended up with a blister!)

 The WNA audiophile "complete" kits have no oscillation problems at all and David says:

 "Decoupling and grounding is not too much of an issue with audio opamps, an OPA134 for instance, but the LM6171 is really a radio or video frequency opamp and grounding/decoupling does matter - as some of you have found out the hard way. It looks like the electrolytic capacitors on the rail splitter need to be at least 220uF to give layout and wiring independence. I have been shipping the cased kits with either 47uF Oscon SP series or 100uF Rubycon ZA series capacitors with no problems ( that anyone's told me about that is ). Another feature of the cased kits is that the pcb sits only a couple of mm above the bottom of the metal case which is connected to signal ground at one of the phono socket shells. So the amp is working against a good ground plane - this may be why I get away with smaller capacitors."

 Seems to make sense so if you're going down the "DIY your own parts and wiring" route it's probably prudent to keep the wiring to a bare minimum and make sure the amp is working against a good ground plane as described above..... The kit supplied by WNA has taken all these variables into account and is stable from the word go but this extra info will ensure that future builders going down the "DIY your own parts and wiring" route won't anger the oscillation god 
	

	
	
		
		

		
		
	


	




 All the best Jim.

 Mike.


----------



## 1UP

Mike, did you have a go at building the Cascode PSU yet? I'm interested in your thoughts on how it improves over the wallwart.


----------



## JHouser

Anyone done a comparison between the PPA and The WNA yet? Still looking for that High-end solution for my 40ohm Grados 
	

	
	
		
		

		
		
	


	



 Thanks!!

 J-


----------



## guzzler

Seems like this a problem with low impedance caps in that position; the oscillation seems to be occuring with higher values. Higher value electrolytics have a lower impedance, all else being equal so this would appear to be the problem. You should read the OS-CON application notes for more information if you're curious...

 g

 PS, still not sure whether to jump on the WNA group buy, very tempting but I've already got plenty of amps to getting by with... So many things, so little time (and money... 
	

	
	
		
		

		
		
	


	




 )


----------



## PinkFloyd

I spent an enjoyable few hours building up another WNA from spare parts I had kicking around and wanted to ensure the oscillation god didn't present himself in the finished circuit so I played particular attention to the following:

 1: Fitted 220uF Cerafines instead of the 100uF in C3 & C5
 2: Used shielded cable from phono inputs to pot and from pot to board input
 3: Used twisted runs for the DC in and LED
 4: Fitted Ferrite Bead Inductors in place of all of the zero ohm links
 5: Lined the bottom of the enclosure with plastic and fitted the PCB 5mm from the bottom of the enclosure (5mm gap)

 Fired her up and and she works perfectly..... completely 100% A ok.

 From this I am in agreement with Dr. White that oscillation is probably being caused in some amps due to the layout of the wiring... as long as you keep it short and sweet and use shielded cable then there will be no visits from the oscillation God 
	

	
	
		
		

		
		
	


	




 I've since replaced the 10R resistors (R7 and R8) with 8R5 varieties which has increased the quiescent current by about 15% so the amp is now drawing about 150mA. I've upped the size of the heatsinks to dissipate any additional heat (there's not that much difference) and the amp has certainly got a tad more grunt than the one with the 10R fitted... seems to make a better job of driving the AKG K-501's too 
	

	
	
		
		

		
		
	


	




 Now I'm confident the amp is firing on all four cylinders I'll strip her out of the enclosure and tidy the wiring up even more.. Here's what she looks like at the moment:





 Under the bonnet





 Close up showing the Ferrite bead inductors in the jumper positions





 Pot and head-socket prepared ready for fitting





 Overhead view... ouput caps held together by araldite and coated with sealant





 Close up of PCB


----------



## BrokenEnglish

wow, mike... you're so fast! i suppose this will be mine, am i on the right track? 
	

	
	
		
		

		
			





 btw... what's the gain-setting for this one?


----------



## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_wow, mike... you're so fast! i suppose this will be mine, am i on the right track? 
	

	
	
		
		

		
		
	


	




 btw... what's the gain-setting for this one?_

 

This was a test amp to see if the oscillation God made an appearance Udo


----------



## jpmoon

Yesterday I filled another pcb with all of the left over parts, a lower spec WNA amp for the computer, 2 x OPA134 and a TL071 in the rail splitter. I recycled the Oscons that had worked fine in the board with the LM6171s. Result - oscillation that seemed to be only dependant on the presence of the Oscons. I'm using THE same plug-top PSU.

 Bog standard electrolytics - fine. I even borrowed some alternative caps (100uF 25v they are twice the size of 100uF 20v Oscons) - also fine.

 If the oscillation god doesn't get you the first time..........

 John.


----------



## StevieDvd

Stupid question but form the latest pictures of the last few WNAs built everyone has been using the big red/orange caps. In the first couple of WNAs these were just jumpered - any reason?

 To the novice like me it seems strange that the 2 biggest components are optional!

 Steve


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Stupid question but form the latest pictures of the last few WNAs built everyone has been using the big red/orange caps. In the first couple of WNAs these were just jumpered - any reason?

 To the novice like me it seems strange that the 2 biggest components are optional!

 Steve_

 

Input caps make the amp virtually bullet proof and you can use it with any source so fitting the input caps ensures the amp will have no probs with tricky sources.

 On the whole, however, 98% of sources will have output caps so input caps in the WNA are not essential and some say the amp sounds better without input caps.. Your amp is actually better without them Steve... if you ever sell your amp on it may be prudent to fit input caps just to be 100% sure the amp will be ok with the buyers source.

 Hope this has answered your question.

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *jpmoon* 
_Yesterday I filled another pcb with all of the left over parts, a lower spec WNA amp for the computer, 2 x OPA134 and a TL071 in the rail splitter. I recycled the Oscons that had worked fine in the board with the LM6171s. Result - oscillation that seemed to be only dependant on the presence of the Oscons. I'm using THE same plug-top PSU.

 Bog standard electrolytics - fine. I even borrowed some alternative caps (100uF 25v they are twice the size of 100uF 20v Oscons) - also fine.

 If the oscillation god doesn't get you the first time..........

 John._

 

Those OSCONS are a bugger and I avoid them like the plague in the WNA.. if they cause oscillation once then maybe it's a one off but twice and they're in the bin. I tried two lots from different batches and they caused oscillation so I won't be trying a third pair. If in doubt go 220uF 
	

	
	
		
		

		
		
	


	




 On the subject of oscillation I've finally completed the oscillation test rabbit WNA and I couldn't for the life of me get it to oscillate.... as stable as a rock.

 I decided to fit a switch so to make this amp 100% oscillation god proof I fitted a huge ferrite ring around the DC in cable and pumped it full of hot glue. I attached it to the enclosure using a combination of sticky fixer and hot glue... this along with the ferrite inductors in place of the zero ohm links and fixing the board 5mm from the bottom of the enclosure has basically put the amp into stealth mode and there is no way the oscillation god even knows I made it... it's invisible to him 
	

	
	
		
		

		
		
	


	




 sounding superb too!!





 Oscillation god defence barrier 
	

	
	
		
		

		
		
	


	








 WNA running in stealth mode.





 Close up of the pot wiring.





 Overhead view which we can see but the oscillation god can't 
	

	
	
		
		

		
		
	


	




 (fingers crossed!)


----------



## StevieDvd

Quote:


  Originally Posted by *PinkFloyd* 
_Input caps make the amp virtually bullet proof and you can use it with any source so fitting the input caps ensures the amp will have no probs with tricky sources.

 On the whole, however, 98% of sources will have output caps so input caps in the WNA are not essential and some say the amp sounds better without input caps.. Your amp is actually better without them Steve... if you ever sell your amp on it may be prudent to fit input caps just to be 100% sure the amp will be ok with the buyers source.

 Hope this has answered your question.

 Mike._

 

Yep it has, I was thinking of making a neater job of the output caps and wondered whether to fix them down to the pcb near to where the C1 caps would be. If for some reason the input caps were recommended to be added at a later date it would affect where I re-located the output caps.

 I'll take a picture so you can see how/where I've located the output caps.

 Thanks teacher


----------



## PinkFloyd

Quote:


  Originally Posted by *StevieDvd* 
_Yep it has, I was thinking of making a neater job of the output caps and wondered whether to fix them down to the pcb near to where the C1 caps would be. If for some reason the input caps were recommended to be added at a later date it would affect where I re-located the output caps.

 I'll take a picture so you can see how/where I've located the output caps.

 Thanks teacher 
	

	
	
		
		

		
		
	


	


_

 

Yes, good idea to fit the output caps on the free board space at C1 you can get sticky back cable tie holders and fix them to the board... sit the caps in them and secure with a cable tie thus:


----------



## Alick

Very interesting. Until now, I think we'd all been pointing the oscillating finger at the high bandwidth LM6171, but John seems to have ruled that out.

 FWIW, I built my amp with no input cap's; it's fine.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Very interesting. Until now, I think we'd all been pointing the oscillating finger at the high bandwidth LM6171, but John seems to have ruled that out.

 FWIW, I built my amp with no input cap's; it's fine._

 

Yep, the evidence is there for all to see but there is something in the wiring also.... if you make a pigs ear of it the LM6171 will oscillate..... 220uF V 100uF also helps in some cases (5 instances I'm aware of where substituting C3 & C5 with 220uF cured the prob) I think we were aware of the random OSCON problem quite a while back in the thread when I experienced a very hot finger moment


----------



## PinkFloyd

Completed sounding great now just have to find a decent volume knob


----------



## 1UP

Pinkie, that looks nice. I like the idea of a power switch!

 Any comment on my "have you tried building a cascode psu" question?


----------



## PinkFloyd

Quote:


  Originally Posted by *1UP* 
_Pinkie, that looks nice. I like the idea of a power switch!

 Any comment on my "have you tried building a cascode psu" question?_

 

Sorry I must have missed that question 
	

	
	
		
		

		
		
	


	




 I haven't tried building one but I do know that Captain bought one from WNA and I believe he likes it.... I use and open frame Calex linear PSU with mine and it's pretty good.


----------



## Captain

Here is a photo of the cascode psu that David built. It is his prototype so their are no solder mask and no silk screened component locations.


----------



## hackeron

This was probably mentioned before, but the Meier-Audio CORDA HA-1 MkII has a natural crossfeed filter with stereo, low and medium setting options.

 Is it possible to add this crossfeed to the WNA so its not a separate unit?


----------



## Alick

Hackeron - see the top of p20 of this very thread for something similar.


----------



## hackeron

Quote:


  Originally Posted by *Alick* 
_Hackeron - see the top of p20 of this very thread for something similar._

 

 Thanks for that.


----------



## 1UP

Captain - how does the Cascode compare to the wallwart, in terms of sound quality differences? And which headphones do you use?


----------



## Captain

Quote:


  Originally Posted by *1UP* 
_Captain - how does the Cascode compare to the wallwart, in terms of sound quality differences? And which headphones do you use?_

 

In my option it seems to open the sound up more and gives better separation of instruments and vocals. The wallwart sound seems a bit more compressed. I am using Grado PS-1's.


----------



## PinkFloyd

Dr. White has been experimenting with several different opamps in the WNA to see if there is anything on a par with the LM6171 which doesn't require the use of output caps and he has come up with the AD-811 which he says comes very close to the LM6171 indeed.

 It has a slew rate of 2500 and is a direct drop in dip8 replacement... no need to optimise the circuit just roll it in. He reckons the AD-811 actually makes the AKG K-501 headphones sound "bassy" so you can be sure this is one opamp I _*will*_ be rolling in 
	

	
	
		
		

		
			








 I've ordered a couple and will report back once I've had a good listen... all I can say, if they come close to the LM6171 and dispense with the output caps then this is one good find 
	

	
	
		
		

		
		
	


	




Datasheet

 All the best.

 Mike.


----------



## Alick

Quote:


 all I can say, if they come close to the LM6171 and dispense with the output caps then this is one good find 
 

I can't wait. Report here the minute you get them fitted...


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I can't wait. Report here the minute you get them fitted..._

 

Will do Alick! I've ordered a couple of samples from AD and it says the estimated date of arrival is 28/12/04 so not long to wait 
	

	
	
		
		

		
		
	


	




 I was messing about the other day and replaced all 4 of the 10R resistors (R7 & R8) with 8R resistors to up the quiscient current by around 20% and the amp certainly does have a tad more "grunt" about it.. the transistors don't appear to be running any hotter either though it's probably best heatsinking them if you ever want to go down the 8R route.... it sure does sound a bit meatier with the 8R resistors in place 
	

	
	
		
		

		
		
	


	




 The more I get into this amp the more I realise that "little" tweaks can bring about quite a major improvement... for example, remove the 47K input resistors and replace with 10K resistors..... substitute the 50K pot with a 10K pot... a bit more clarity. Fitting cerafines in place of el cheapos in C3 and C5 also helps improve things. Probably the most essential part of the amp if using LM6171 is the cable layout "and" the quality of the cable.. it sure does sound a lot better if everything is kept as short as possible and well routed around the PCB, from now on I may not even use an on / off switch as that introduces 2 further long runs of cable inside the amp...nope I think the secret to the WNA is to keep everything as simple as possible. The ferrite bead inductors in place of the zero ohm links are also a very good idea.

 It takes time to get used to the inner workings of the WNA and time to iron out little gremlins like the Oscillation God but a build pattern is being weaved and it's becomming increasingly very easy to pinpoint and rectify any minor glitches... 

 Great fun


----------



## Alick

Next to the fantastic sound, the endless tweaking potential is a major plus for me too. I've aquired some of David's thin coax (along with gold-plated header pins) which I'm using to rewire the amp during the Christmas holiday along with a LM6171 to replace the TL071 I used for the rail-splitter. You'll remember that I took a lot of convincing that the LM6171 was worth adding output capacitors for, although I'm happy to admit I was wrong. However, I still have this nagging conviction that the amp could sound even better if a suitably fast and accurate op-amp with a low DC offset could be found, allowing the capacitors to be eliminated. I'm really hoping that David has discovered the holy grail...


----------



## Bassivus

Hi everybody,

 I got my camera back today so I can finally show you my recently finished wna…































 The volume knob is not the final solution...






 Amp looks small compared to my instrument 
	

	
	
		
		

		
		
	


	









 Bipolar 100uFx2 pro channel output caps in the “super E” formation






 And finally my oscillation-god-scare-away-mantra-ferrite-ring 
	

	
	
		
		

		
		
	


	




 under the heatshrink


----------



## Alick

Lovely job...


----------



## 1UP

Beautiful. It's hi-fi-furniture!


----------



## PinkFloyd

Bassivus, that's a superb looking job you've made of that amp the front panel looks so organic, flowing and natural and I love the way the blue light surrounds the volume knob... very nice workmanship indeed 
	

	
	
		
		

		
		
	


	




 How are you finding the music, does the amp sound neutral to you?

 All the best.

 Mike.


----------



## Bassivus

Thanks Mike. I’m pretty satisfied myself with the way all came out with the front panel 
	

	
	
		
		

		
		
	


	



 And the sound! After all it’s why we all are here. I expected the amp to sound good after reading all that was written on this thread, and found that it is even more than I was hoping for when I decided to go for it. Simply the high end-for peanuts! Very neutral. Great dynamics and timing with all the types of music, from classic, jazz or electronic, they all sound superb. 
 It sounded good from the beginning with the Nitai 22uF output caps. When I first tried the amp with Fisher & Tausche 100uF pair pro channel installed it sounded muddy. I left the amp ON, playing for 16 hours and things got much better and clearer 
	

	
	
		
		

		
		
	


	




 I have left output caps non soldered for testing purposes so I did some more A B testing and comparing. After extended comparing I can say that to my taste Nitais tend to gently smooth down the highs and are little thin down at the bottom end. Its like smooth against crystal. With my sennn HD590 it may even be a good thing, but I’m planning to go for AKG 501. The F&T caps in the “super E” configuration after the proper burn in gave the amp even more holographic precision in positioning the instruments, and further firmed on already tight bass. Now my CD headphones out compares to WNA like watching TV against the real thing! 
	

	
	
		
		

		
		
	


	




 All the best Ivica.


----------



## Madcat05

Bassivus, your amp looks amazing. very classy. I like the way the volume knob looks with the wood. Good job.

 sorta off topic but, does anyone know who makes the black case the WNA Kit comes with, or where I could get it?

 I'd like to use to recase my PIMETA in, Thanks.


----------



## Syzygies

Quote:


  Originally Posted by *Madcat05* 
_does anyone know who makes the black case the WNA Kit comes with, or where I could get it?
_

 

Sure looks like a Hammond to me, which is what everyone uses who goes for this look: http://www.hammondmfg.com/1455.htm. A variety of sizes; pay close attention to the cross-sections drawn in the PDF files. http://www.mouser.com is one source.

 There are knock-off brands at Fry's, but not worth bothering with.


----------



## Alick

I'm pretty sure that the WNA case is *not* a Hammond. Most people built their WNAs into Hammond cases before the cased kit was launched, but the "official" case  doesn't look like any Hammond I've seen. (Pink Floyd probably has a better picture of the case and an idea of its provenance).


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I'm pretty sure that the WNA case is *not* a Hammond. Most people built their WNAs into Hammond cases before the cased kit was launched, but the "official" case  doesn't look like any Hammond I've seen. (Pink Floyd probably has a better picture of the case and an idea of it's provenance)._

 


 Hi Alick,

 The WNA enclosures are similar to the ones found at Maplins they are far from "exotic" but they are a good size and David uses them because they come in a very wide range of sizes that happen to suit the sizes of his pcbs very well. He sends them off to be black anodised and he says this makes them almost scratch proof.

 The Hammond is a much nicer looking enclosure, the WNA one is industrious looking and serves a purpose but all the money has been put into the sound end of the amp and not into cosmetics.

 The black Hammond looks very good and far less common looking than all those aluminium ones you see everywhere you look 
	

	
	
		
		

		
			










 Mike.

 PS: I believe David sells these anodised enclosures, ask him for the current price.


----------



## PinkFloyd

Cracked it!

 Fitted 2 x Cerafine 220uF in C3 & C5 and the amp oscillated causing TR3 & TR4 to heat up..... I replaced the LM6171 in IC2 with a OPA134 and the oscillation disappeared.

 I'd run out of 25V 220uF Cerafines so had fitted "35V" 220uF Cerafines instead.... I wondered if the higher voltage rating caps could be causing the rail splitter LM6171 opamp to oscillate...... 

 It was out with the 35V 220uF cerafines and in with 2 x 25V 220uF cerafines I poached from another amp...... no oscillation at all with the lower voltage caps.

 So, it appears the LM6171 prefers low voltage caps in C3 & C5.... probably 16V would be the ideal voltage rated cap to use.... you can safely use larger voltage caps in C3 & C5 if you're using an alternative to the LM6171 in IC2, I tried some 470uF 35V cerafines in C3 & C5 with an AD825 in the rail splitter and it works perfectly... roll in the LM6171 and "bingo" prepare for heat from TR3 & TR4.

 I'm glad I found this out as these random oscillation gremlins have been really hard to pinpoint..... keep C3 & C5 below 25V and there should be no probs  I reckon it would be a good idea to avoid low impedance caps in C3 & C5 also.


----------



## Sewer Guy

Hi Pinkie & all WNA'ers. As you know I have used the LM 6171's quite a bit both personally & at work. There should be no problem using them as audio amplifiers & line drivers for both audio & baseband video.

 I do question its use in a rail splitter application, its wide bandwidth & high slew rate could definitely contribute to instability in that configuration. It would be better to use a TL082 or other equivalent device as the rail splitter. 

 I have been following this thread with interest. Keep up the good work.


----------



## PinkFloyd

Quote:


  Originally Posted by *Sewer Guy* 
_Hi Pinkie & all WNA'ers. As you know I have used the LM 6171's quite a bit both personally & at work. There should be no problem using them as audio amplifiers & line drivers for both audio & baseband video.

 I do question its use in a rail splitter application, its wide bandwidth & high slew rate could definitely contribute to instability in that configuration. It would be better to use a TL082 or other equivalent device as the rail splitter. 

 I have been following this thread with interest. Keep up the good work._

 

Hi Bill,

 Long time no see, good to have you back 
	

	
	
		
		

		
		
	


	




 I know you are an absolute expert on the LM6171 so really welcome your advice re: using them in the rail splitter section. Apart from the TL082 are there any others you could recommend? To date all the following have worked without glitch: OPA134, AD825, AD8065 and OPA627... any others you could add to this list? The rail splitter op amp does have an effect on the sound but maybe the LM6171 is just a tad "too" fast.. it sounded great with OPA627 and AD825.... is there anything else along those lines that you'd recommend or would you just stick with TL082 ?

 Good to see you back mate!

 All the best.

 Mike.

 Edit: Just checked, TLO82 available from Rapid for 38pence each


----------



## Alick

Quote:


 Cracked it! 
 

Well done Sherlock!

 (Maybe I should rethink rolling that LM6171 into the rail splitter...)


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Well done Sherlock!

 (Maybe I should rethink rolling that LM6171 into the rail splitter...)_

 

May be a good idea Alick... try it, if it works then all's well. I'm listening right now with an AD-825 in the rail splitter and I do believe there's a slight degree more warmth to the proceedings... all the same speed and attack of the LM6171 trio but with a tad more warmth, maybe due to the fact I've got a slight cold however 
	

	
	
		
		

		
		
	


	




 It could also be a mixture of the AD and LM signatures giving you the best of both sounds but maybe that's a bit far fetched..... you never know though 
	

	
	
		
		

		
		
	


	




 Over the hoilday period I'm going to really try a wide variety of different components into the PCB to see what effect different brands etc. has on the sound..... the AD-811 will be here on the 28th so that'll be first under the bonnet! One thing's for sure.... fitting 8 ohm resistors instead of the 10R resistors in R7 and R8 has brought about a good 20% increase in grunt making the amp sound a good bit more ballsy and if these AD-811's are all they're cracked up to be then they'll turn the amp into a bass powerhouse..... not to everyone's taste but may suit Grado owners 
	

	
	
		
		

		
		
	


	




 Why not build up another amp Alick? I'm getting addicted to soldering again..... not good 
	

	
	
		
		

		
		
	


	




 I've also found it's a lot easier if you make the amp up in modules ie:

 Prepare the potentiometer with the cabling ready to solder onto the phono sockets and board.

 Fit the headsocket with the dummy resistors and caps ready to install.

 Wire up the board with the power wire, output cables and Led on a length of wire.

 It all slots together a lot easier. I've also got into hot glueing the wires on top of the board (where they enter the holes to be soldered) to ensure there is no way they can move... I also hot glue the headsocket "module" the beauty of the hot glue is that it provides excellent strain relief and should it become necessary to service the amp at any time it's easy to pick off.... I totally seal the headsocket "module" so it would have to be replaced with a new module if any part of it were to fail over the years but it's as cheap as chips to make one up so no worries. 

 Anyways, enough on my new glue gun... it's almost as addictive as soldering


----------



## Jan Meier

Dear Headfellows,

 Do you guys know that there are headphone amps on the market that:

 - Use the LM6171
 - Use fast capacitors throughout and yet are stable.
 - Do not use coupling capacitors as offset problems are eliminated by appropriate circuitry
 - Have crossfeed on board

 ???

 The circuitry of the simplest version of these amps can be found at:

http://home.t-online.de/home/meier-audio/headamp.htm

 Cheers,

 Jan


----------



## PinkFloyd

Edit: I must check links before commenting on the content of a webpage.

  Quote:


  Originally Posted by *Jan Meier* 
_
 Do you guys know that there are headphone amps on the market that:

 - Use the LM6171
 - Use fast capacitors throughout and yet are stable.
 - Do not use coupling capacitors as offset problems are eliminated by appropriate circuitry
 - Have crossfeed on board

 ???
_

 

Yes, perfectly aware of your DIY design Jan but I love the sound of the WNA. It's first class and Dr. White has really managed to design an amp which suits my ears.. it's very British sounding with regard to spot on timing, refinement and neutrality and I luv it 
	

	
	
		
		

		
		
	


	




 He also utilises the full speed of the LM6171 which is why the seperation and clarity are just so fabulous IMO.

 There are no issues with the WNA kit amp just a _few_ people have experienced the odd instance of oscillation when using non standard caps........ easy enough to work round 
	

	
	
		
		

		
		
	


	




 On reflection I'm not too sure I'd want crossfeed in the WNA, the sound is absolutely crystal clear and not at all fatigueing so there's not much use for it unless you want to tidy up extreme stereo recordings... plus it means a switch in the signal path which isn't good news. The standalone crossfeed is excellent and I use it on the very rare occasions when I listen to some of the Beatles extreme recordings.


----------



## Alick

Quote:


 not to everyone's taste but may suit Grado owners 
 

My HD650's have arrived, so I've a foot in both camps these days. 
	

	
	
		
		

		
		
	


	



  Quote:


 Why not build up another amp Alick? I'm getting addicted to soldering again..... not good 
 

Mmmm, just what I was thinking. I'm rewiring the WNA over christmas, but then I'll need something else to play with. I was thinking of getting the complete WNA kit but, since I have a WNA already, maybe I'll think about giving Jan's circuit a try so we can compare and contrast. Jan - is there a PCB available for the amp in the link or do folks build it up on stripboard?


----------



## Duncan

Quote:


  Originally Posted by *PinkFloyd* 
_Over the hoilday period I'm going to really try a wide variety of different components into the PCB to see what effect different brands etc. has on the sound..... the AD-811 will be here on the 28th so that'll be first under the bonnet! One thing's for sure.... fitting 8 ohm resistors instead of the 10R resistors in R7 and R8 has brought about a good 20% increase in grunt making the amp sound a good bit more ballsy and if these AD-811's are all they're cracked up to be then they'll turn the amp into a bass powerhouse..... not to everyone's taste but may suit Grado owners 
	

	
	
		
		

		
		
	


	


_

 

Having replaced the LM6171 with an OPA627 I can say very conclusively that the perceived sound quality has improved substantially (using the RS1s)

 I'm not sure if I myself would want any more bass than what is on offer... I guess I won't know until I try lol, but - as 'stock', the bass is incredibly tuneful with the RS1, so I cannot see a requirement for more...

 Hopefully getting a new solder station today, so if I get that, it'd only be a 20 second job to swap them... might be worth a try I suppose


----------



## Alick

Quote:


 Having replaced the LM6171 with an OPA627 I can say very conclusively that the perceived sound quality has improved substantially (using the RS1s) 
 

Duncan; did you replace the rail splitter op-amp or the ones in the audio path?


----------



## Duncan

Quote:


  Originally Posted by *Alick* 
_Duncan; did you replace the rail splitter op-amp or the ones in the audio path?_

 

Sorry, should've made that clearer... is just the rail splitter


----------



## jude

Quote:


  Originally Posted by *PinkFloyd* 
_....Thing is, Dr. White's circuit sounds out of this world and the "price" has to be the head-fi bargain of the century..... Your amps may / may not come close to the performance of his amp but your prices are way too heavy for the DIYer to comprehend...... Instead of blatantly marketing your amp in this superb thread maybe you can chip in with your experience of the LM6171 and contribute to it with your ideas...... that would be most welcome Jan. Please remember this is the DIY forum 
	

	
	
		
		

		
		
	


	


_

 

Mike, did you actually read the page that Jan linked to? I checked the link provided by Jan, and it is a project page that provides useful information on the LM6171, as well as schematics germane to his discussion in that article that does, as you asked for, "chip in" with his experience with the LM6171.


----------



## PinkFloyd

Quote:


  Originally Posted by *jude* 
_Mike, did you actually read the page that Jan linked to? I checked the link provided by Jan, and it is a project page that provides useful information on the LM6171, as well as schematics germane to his discussion in that article that does, as you asked for, "chip in" with his experience with the LM6171._

 

No Jude I didn't read the page I wrongly assumed it was a link to a commercial amp, apologies to Jan my mistake.


----------



## PinkFloyd

Ok folks,

 Here's the deal if you want to use the LM6171 in the WNA without output caps. David didn't want to adopt this approach in the Kit amp as it is supply voltage dependent and the end user may be using a power supply ranging anywhere from 12V - 36V. The output caps can be used with any voltage of PSU in the 12V - 36V range so they cover all bases.

 This mod is  *only* for WNA owners who are using the recommended 24V power supply.

 Fit a 10M resistor between pins 3 and 4 of the LM6171, it will give you an output offset of -8.5mV. You have to do the mod for both IC1 channels. Do not apply this mod to IC2 (the rail splitter) 

 David suggests that a 9.1M resistor will give the "lowest" offset with a 12V supply (12V per rail). These are quite tricky to get a hold of but I believe Maplins stock the 9.1M value. If people _are_ using different supply voltages they will need to increase the value of the resistor for higher voltages or reduce it for lower voltages. There will be some variation from LM6171 to LM6171 so always check the offset with your particular amp before you connect the headphones. Remember, this mod is specifically for the WNA's being powered by the recommended 24V voltage. 

 This mod means that you can dispense with the output capacitors should you wish to do so. I haven't got a clue what difference this will make to the sound quality as I'm right out of 10R resistors so it looks I'll have to wait till after Christmas before I can get my hands on a couple to try.... 9.1M is the optimum value and if you can source them easily enough then go with them but the 10M has been fully tested at WNA HQ and is very stable and there is no fluctuation of offset with temperature changes.

 Always check the offset before you connect the headphones and ensure it's under 50mV.

 This diagram shows you where to connect the resistor, the opamp is shown from the top view..... solder 10M resistor between 3 & 4 (highlighted in red) you can fit the resistors under the board or solder directly onto the legs of the LM6171 on top of the board..... it's up to you.


----------



## Alick

I've got to try this! Unfortunately, I've no 10M resistors at the moment either, but Maplins sale starts on Boxing Day. I feel a trip to Gorgie Road coming on...


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_I've got to try this! Unfortunately, I've no 10M resistors at the moment either, but Maplins sale starts on Boxing Day. I feel a trip to Gorgie Road coming on..._

 

Where the heck is Gorgie Road Alick? My nearest Maplin is Aberdeen though I generally order from them online (saves petrol) there's not one in Fife as far as I'm aware?

 Mike.

 PS: If Gorgie Road is within striking distance we could meet up sometime in the New Year and grab a burger. I don't do big cities these days and try to avoid them as much as possible but if parking is easy and there's a burger joint to hand I'm more than happy to make an exception to the rule and will happily discuss lead free solder V 60 / 40 till the cows come home


----------



## damitamit

hmmm, interesting!

 I'll go past the Maplin superstore on my way to uni tomorrow morning, so ill pick up a few 9.1M resistors. 

 Email me your addresses and ill pop a couple in the post for ya tomm so you can have a play over crimbo. Thou i'm not sure when it will get there 
	

	
	
		
		

		
		
	


	




 It will be my xmas pressie to fellow WNA-fiers!


----------



## Madcat05

I contacted David about the anodized enclosures, and he does sell them seperatly, for £15 and £5 shipping to Canada. There abit expensive due to David having them anodized.

 Just thought I'd let people know what I found out.


----------



## Alick

Quote:


 Where the heck is Gorgie Road Alick? My nearest Maplin is Aberdeen 
 

It's in Edinburgh which is where you'r nearest Maplin really is (although not Gorgie Road though, I got that slightly wrong), it's in nearby Dalry Road. I'd love to meet up for a burger or something, although damitamit's kind offer seems too good to pass up on.


----------



## PinkFloyd

Quote:


  Originally Posted by *Madcat05* 
_I contacted David about the anodized enclosures, and he does sell them seperatly, for £15 and £5 shipping to Canada. There abit expensive due to David having them anodized.

 Just thought I'd let people know what I found out._

 

I'm always 100% honest and hate to offend the anodised enclosures but they are "dire" sure they are functional but they are far from quality and are as aesthetically pleasing as an anodised corned beef tin. They do a job and that's it...... your money buys the parts that make the sound, the enclosure is a "get you going" device and the Hammonds are a much better fit and finish IMO.

 I'm not slating the WNA enclosure but it's far from quality.


 Mike.


----------



## damitamit

I have to agree with Pinkie on the cases.

 I've used those Maplins cases for my Ra-1 clone and my gainclone. The edges aren't always smooth, and the cases usually just dont fit right. Also when you use a really long one the screws have to be on the front of the case, which isnt very sightly.

 However, they do tend to look quite nice after 5 coats (sanding in between) of black car spray paint, which is what the guy I sold my ra-1 clone to did. Thou he's a real perfectionist so i doubt i could get it looking like that. Ill try get him to post some pics of it.


----------



## Madcat05

I won't be getting a case from David as I can get a Hammond for less from DigiKey, which is located in Canada so shipping is cheaper.

 I'm not really fond of the silver end enclosures, but Pinkie I see you've used a black end Hammond.

 Could you link me to it on Hammond's site?


----------



## PinkFloyd

Had a bit of a brainwave regarding the 10M resistor being fitted between legs 3 & 4 of the LM6171 and here is the result:






 Yes, 3mm long chip resistors which will sit on top of the LM6171 legs absolutely perfectly.. no need to go under the board and no need to fit dangly resistors with this solution.

 100 x 10M chip resistors cost 70p here they are I've ordered 100 so they should be here tomorrow with a bit of luck.... I'll let you know how I get on with them 
	

	
	
		
		

		
		
	


	









 All the best.

 Mike.


----------



## Alick

Brilliant idea! They're metal film, high stability so perfect for the job. Bonus is, being 5%, you might get lucky and find a couple around 9.5M. They'd fit quite nicely under the board too, although putting them on the leg makes sense as you won't have to desolder them if you want to roll-in any alternative op-amps.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_Brilliant idea! They're metal film, high stability so perfect for the job. Bonus is, being 5%, you might get lucky and find a couple around 9.5M. They'd fit quite nicely under the board too, although putting them on the leg makes sense as you won't have to desolder them if you want to roll-in any alternative op-amps._

 

Yep, that's why I chose 5% over the 1% variants.. also the 5% are longer (3mm) and will be an absolutely perfect fit on the upper section of the LM6171 legs allowing the lower sections of the legs to fit into the dip8 socket as usual... I'll select a few 9.5M ones and send them over to you Alick.

 All the best.

 Mike.

 EDIT: Could also be very unlucky and find all the 100 resistors measure 10.5M


----------



## damitamit

Neat solution mike!

 I went to Maplin today. They don't sell 9.1M so got a few 10M resistors. A couple are on their way to you as we speak Alick.

 Will try them out tomorrow hopefully...


----------



## Alick

Quote:


 I'll select a few 9.5M ones and send them over to you Alick. 
 

You're a true gent. The burgers are on me if we manage to meet up over the holidays.
  Quote:


 Could also be very unlucky and find all the 100 resistors measure 10.5M 
 

Even if we are that unlucky, the few extra mV offset shouldn't cause any issues given that there's about 38mV elbow room. I suppose it's most likely to be a normal distribution, so approx. 98% of them should be between 96.66M and 103.66M if my metal arthmetic isn't too mental.


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_putting them on the leg makes sense as you won't have to desolder them if you want to roll-in any alternative op-amps._

 

Speaking of rolling in other opamps 
	

	
	
		
		

		
		
	


	









 The AD-811 arrived today and they are bloody incredible (even with the output caps in place) they're very much in the same style as the LM6171 but there's a tad more warmth and full bodiedness about them. The have the same speed, seperation and attack of the LM6171 but seem to add a touch more soul, they're analytical without being clinical and I think they are damn fine splendid in the WNA!

 I'm going to wait until the WNA is output cap free (after fitting the 10M to the LM6171) then I can really have a listen to both of these opamps "naked" without output caps in the way...... I'll send the AD-811 over to you after Christmas Alick for a second opinion and you can also compare LM6171 to AD-811 without the dreaded output caps in the way 

 This has been, yet another, great week for the WNA and with the output caps out of the way we can now hear the true potential of the LM6171 and the new AD-811 find....... looking good!!!


----------



## PinkFloyd

Quote:


  Originally Posted by *damitamit* 
_However, they do tend to look quite nice after 5 coats (sanding in between) of black car spray paint, which is what the guy I sold my ra-1 clone to did. Thou he's a real perfectionist so i doubt i could get it looking like that. Ill try get him to post some pics of it._

 

heh,

 The Chiarra / Andante kit came with the same unpainted aluminium Maplins enclosures (the larger ones)

 I ended up spray painting the lid a battleship grey colour and the rest of it black.. looked ok but far from an aesthetic work of art, let's just say they looked "unassuming"


----------



## PinkFloyd

Quote:


  Originally Posted by *Madcat05* 
_I'm not really fond of the silver end enclosures, but Pinkie I see you've used a black end Hammond.

 Could you link me to it on Hammond's site?_

 

Hi,

 The part number is 1455N1602BK I get mine here


----------



## Madcat05

Thanks PinkFloyd. 

 I can get that one for more than half the cost of the one David sells.


----------



## Alick

Quote:


 I'll select a few 9.5M ones and send them over to you Alick. 
 

 Quote:


 I'll send the AD-811 over to you after Christmas Alick for a second opinion 
 

 Quote:


 got a few 10M resistors. A couple are on their way to you as we speak Alick. 
 

You guys are going to give my postie a hernia. OK, maybe not, but you know what I mean. 
	

	
	
		
		

		
		
	


	




 What can I say, but thanks!


----------



## PinkFloyd

I've just realised this thread is 6 months old and what a great six month's it's been!

 When I first took delivery of the board from Dr. White I didn't know what to make of it as it was unchartered territory and was purely a £30 "suck it and see" punt.

 I'm so glad I parted with that £30 
	

	
	
		
		

		
		
	


	




 I'd just like to thank Dr. White for all his work on making the amp what it is today, he really is a valuable asset to the Hi-Fi community and is a true gentleman who is passionate in his work and strives to provide the best possible sound for the pound. he's been an absolute gem of a guy to communicate with and I have learn't a lot from him over the past few months as well as benefiting from the aural magic the WNA delivers.

 I'd also like to thank the contributors to this thread for their ideas and inspiration, this is one of the most friendly and informative threads I have ever been involved in and I thank you all for your input.

 The past six months have seen quite a few developments let's hope next year sees a lot more ........ I'd like to see provision on the board for the ALPS blue velvet pot, an on / off switch and headphone socket....... a minor gripe but it would negate the need for hook up wire and would make the kit easier to build 
	

	
	
		
		

		
		
	


	





 All the best for Christmas. (enjoy the 10M and AD-811) may your New Year be output cap free 
	

	
	
		
		

		
		
	


	




 Mike.


----------



## Alick

...and so say all of us. I couldn't have put it better, so...what Mike said. Merry Christmas!


----------



## PinkFloyd

What a great way to spend Christmas Eve.... armed with a multimeter, a few bottles of Hobgoblin Ale and a reel of 100 x 10M chip resistors.

 I managed to find "4" that measured 10M exactly, the other 96 were over the 10M mark and not one was under 
	

	
	
		
		

		
		
	


	




 I fitted them onto the LM6171 (piece of cake and a perfect fit) rolled them into the WNA (minus output caps) and measured the DC offset:

 Left channel: -46.7mV 
 Right Channel: -41.3mV

 Quite a difference from David's -8.5mV readings I think 9M will be needed to get the offset down that low and, even then, -8.5mV is not as good as the "zero" reading you get with output caps fitted.

 50mV or thereabout is not going to damage your headphones (300R Sennheisers) so I had a darned good listen without the output caps and to be totally honest, if there is an improvement I can't hear it... I wasn't expecting miracles but assumed there may be a subtle difference without the output caps but nope, not as far as my ears go... maybe a bat could detect something but I can't.

 The AD-811 offset measured pretty weird:

 Left channel: -0.9mV
 Right channel: -17.3mV






 Must be a fluctuation in the chips.. not very precise.

 The real surprise with offset was the humble Opa 134:

 Left Channel: -0.2mV
 Right Channel: -0.3mV

 I measured offset with 3 independent meters and they all measured within a whisker of each other so these measurements are deemed pretty accurate. Maybe with 2 LM6171's from a different batch the offset would have been lower, who knows, one things for certain though......... I'm sticking with output caps with the LM6171....... there's no audible advantages removing them (not to my ears anyway) and there's one big advantage to using them..... ZERO DC offset.. Nil, none, nada, 0%

 Oh well, it was worth a go and Rapid sure are Rapid! I ordered the chip resistors yesterday at 7pm along with some solder and the package arrived today at 11am!! Now that "is" Rapid especially considering the time of year. 

 Now what the heck can I make with 98 10meg chip resistors?


----------



## Jan Meier

"Quite a difference from David's -8.5mV readings I think 9M will be needed to get the offset down that low"

 No, you need a higher value than 10 MOhm!!!!

 Jan


----------



## PinkFloyd

Quote:


  Originally Posted by *Jan Meier* 
_"Quite a difference from David's -8.5mV readings I think 9M will be needed to get the offset down that low"

 No, you need a higher value than 10 MOhm!!!!

 Jan_

 

Yes, 

 It's looking that way Jan..... though I think the output caps are the best solution in a kit amp considering the different voltages that may be used... 24 - 36V. There will also be variations from one LM6171 to another so a low offset cannot be guaranteed simply by fitting resistors to the -ve power supply rail ( LM6171 pin 4 ) and the + or non inverting input to the LM6171.

 The "bullet proof" solution is to fit output caps which ensures Zero offset irrespective of voltage and this is why Dr. White recommends them in his kit amps, they cover all eventualities with the LM6171 and won't pose any issues with any voltage from 24 - 36V.

 I'll pop out and hook two of the chip resistors together and check the offset with 20M across 3&4.

 ****, so much for enjoying Christmas Eve basting a turkey 
	

	
	
		
		

		
		
	


	




 All the best and have a peaceful Holiday Jan.

 Mike.

 EDIT: oops!....... Drunk in charge of a Multimeter (scuse me your honour it is Christmas Eve) I'm off to baste my bird have a great holiday people!


----------



## PinkFloyd

EDIT!!! too much HobGoblin incorrect reading of the meter!!! OOOPS!!


 Come on guys it "is" Christmas Eve!


----------



## Alick

Quote:


 EDIT!!! too much HobGoblin incorrect reading of the meter!!! OOOPS!! 
 

So what was incorrect? '+' instead of '?' Out by a factor of 10? uV insted of mV? 

 'fess up, Mike...


----------



## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_So what was incorrect? '+' instead of '?' Out by a factor of 10? uV insted of mV? 

 'fess up, Mike... 
	

	
	
		
		

		
		
	


	


_

 

OK.

 I've really been testing the LM6171 without output caps extensively over the past couple of days whilst the rest of you have probably been stuffing yourself with turkey 
	

	
	
		
		

		
		
	


	




 I tried 6 x LM6171's and no two gave measurements that suggested simply whacking a resistor between 3 & 4 is the ideal solution.

 With 10M all of the results were "-mV" and here are the results:

 Chip 1: -48.1mV
 Chip 2: -41.3mV
 Chip 3: -23.5mV
 Chip 4: -13.7mV
 Chip 5: -37.2mV
 Chip 6: -25.8mV

 With 15M all of the results were "+mV" and here are the results:

 Chip 1: +15.9mV
 Chip 2: +24.7mV
 Chip 3: +34.9mV
 Chip 4: +49.0mV
 Chip 5: +27.8mV
 Chip 6: +31.2mV

 I made up quite a few 15M resistors using 3 x 10M resistors suitably configured (series / parallel) to make 15M:





 Pretty small chips to work with but easy when you get the hang of it.

 I then tested each one and selected 6 which where pretty spot on to 15M and then encased these 6 "modules" in hot glue to ensure there was no way of them coming apart:






 I attached these "modules" to the 6 x LM6171's and identified them by heatshrinking different colours onto their wires.

 I used the left channel of the WNA to perform the tests and then the right channel...... both channels measured pretty identical using the same LM6171 in each channel.

 My conclusions are that neither 10M or 15M can be considered "ideal" as all of the chips have to be individually "tuned" to give very low offset.. simply sticking a 15M between 3&4 is far from satisfactory.

 If you are going to remove the output caps I strongly suggest you have a few different resistors to hand as you'll have to "make" the correct ohmage resistor to suit each individual LM6171..... it could be anywhere from 10M to 16M dependant on the individual LM6171 you have... from the above results 12M - 13M may be a good starting point but be prepared to spend a *very* long time finding the value that will give you zero offset.

 I listened to a WNA with the two lowest offset measured LM6171's fitted (-13.7mV & 25.8mV) against a WNA with output caps fitted:






 I won't waste time typing here as I could hear "no" difference between the two.... NO difference at all.

 So, is it worth removing the output caps? IMO no it isn't. With the output caps in place there is ZERO offset and, as such, the full dynamic range will not be affected (any dc offset will pull or push the diaphragm away from its resting point which will reduce it's travel in one direction whilst uselessly increasing it in the other direction) You also risk blowing the crap out of your headphones if one of those resistors falls off 
	

	
	
		
		

		
		
	


	




 Nope, I can fully understand why Dr. White has chosen to use output caps.... zero dc offset, guaranteed protection for your headphones and all this with minimum (if any) insertion loss..... 

 Just my two cents but output caps it is for me considering the variations between LM6171's.... if a set value resistor gave an exact offset reading with "every" LM6171 then fine but due to the wide fluctuations output caps are the bullet proof solution. 

 Merry Christmas!


----------



## PinkFloyd

Another little thing I tried today was to interchange parts from a black Hammond to an aluminium one and vice versa...... I think they look much better than plain black or plain aluminium what do you think?


----------



## Alick

I'll probably still have a go, but it sounds like the output cap's aren't such a compromise after all. I suppose it was wishful thinking that a major improvement could be made so simply to an amp which already sounds so good...

 EDIT: I quite like the "black and silver" look. I could do with getting another case anyway as I slightly bashed one corner of my front panel when I fitted the ALCAPs in a wee bit of a hurry and didn't take as much care as I should have.


----------



## GoRedwings19

Hi dudes I am not a diy'er as I have no clue when it comes to things like this. But I am awaiting delivery of my WNA and I am really excited. Reading the thread has only heightened me excitement even more. I will post impressions initially and then compare notes with you WNA'ers.


----------



## Alick

Couple of (well, three) quick questions: I bought the coax and pin headers used in the complete kit from David to re-wire my WNA, but as I only have the exact quantity of pins, I don't want to screw any up and they didn't come with instructions. So, to Mike or anyone else who's used them:

 1. Did you crimp the pins onto the wire and then add a small amount of solder?
 2. Does the bottom crimp attach to the bare wire and the top crimp attach to the insulation as strain relief?
 3. Which way round does the connector fit into the header body? (I assume there's a 'latching' mechanism).

 TIA.


----------



## PinkFloyd

EDIT: ignore the following it's for standard pin headers and socket housings I didn't realise yours were gold they have a different locking mechanism, check your PM.

  Quote:


  Originally Posted by *Alick* 
_
 1. Did you crimp the pins onto the wire and then add a small amount of solder?_

 

Yes, crimp the pins onto the wire and then flood a small amount of solder into the "gap" in the centre of the pin until it "just" flows out the other end of the pin...... it's simple crimping the pins with long nose pliers, fold one strain relief over then the other. Don't over solder (ie: blobs) or the pin will not fit into the crimp terminal housing.... just enough solder to flood the joint, no more no less.

  Quote:


  Originally Posted by *Alick* 
_2. Does the bottom crimp attach to the bare wire and the top crimp attach to the insulation as strain relief?_

 

Yes, easier if you crimp the bare twisted wire first and then crimp the insulation.

  Quote:


  Originally Posted by *Alick* 
_3. Which way round does the connector fit into the header body? (I assume there's a 'latching' mechanism)._

 

You'll notice a small barb on the back of the connector... when you fit this into the crimp terminal housing you ensure it locks into the small square hole at the back of the terminal housing body (you may have to prod it home with a suitably sized implement to get it to lock) if you want to remove it at any time insert a prodding device into the square hole which pushes the barb inward..... pull upward to release....... 







 When you solder the braid of the cable David supplies you can safely flood it with solder, in fact you could keep your soldering iron on that cable all day and nothing would melt the insulation is resistant to heat 
	

	
	
		
		

		
		
	


	




 Preparing the braided cable....... strip outer sheath, push the braid in the direction of the remaining sheath until it bunches up...... use a watchmakers screwdriver to open a small hole in the "bunched" braid and then hook the conductor out of this hole... in with the driver, under the conductor, bend cable over on itself and hook out the conductor.

 Hope this helps Alick.

 Mike.

 EDIT: oops you were asking about the connection between the crimp terminal housing and straight pin header..... there's no latch it's a friction lock.... this pic will show you which way to connect:


----------



## PinkFloyd

Quote:


  Originally Posted by *GoRedwings19* 
_Hi dudes I am not a diy'er as I have no clue when it comes to things like this. But I am awaiting delivery of my WNA and I am really excited. Reading the thread has only heightened me excitement even more. I will post impressions initially and then compare notes with you WNA'ers._

 

Hi Mike,

 Welcome to the WNA thread your wallet is safe here 
	

	
	
		
		

		
		
	


	




 Can't wait for your comments on the Mark Levinson / WNA combo....... I'm really looking forward to this 

 All the best.


 Mike.


----------



## GoRedwings19

Yippppppppppppppppppppeeeeeeeeeeeeeeeeeeeeeeeeeeee eeeee

 It's here. My WNA amp built for me by pinkfloyd is here. I have been for a while trying to pick one of these up for a while now. I can solder but that's about it, and I don't have a clue with electronics anyway so I asked pinkfloyd if he would build me one if he had time on his hands.

 Well I hooked up the WNA to my ML combo. I used Nordost SPM reference interconnects.

 So the important question is how do I think it sounds?

 I am sorry pinkdude but the amp is not my cup of tea. This is because it totally
 [size=xx-large]Kicks ass[/size]

 Ha ha had you going pinkdude.

 This is the best SS amp I have heard. It is a well known fact I love tube amps more for the warmth and lushness. But this amp is almost there. It really works well with the senn hd600's but you have to crank it up to 11.00 posistion to really get it going. But with the grado's RS-1's it is totally sweet. As far as SS amps go this is a warm amp.

 I use to have a GSP solo amp+PSU1. This was great with the hd600's and the rare hp-1000 series headphones. But I didn't use them with the rest of my grado's as the resulting sound was too bright and painful to my ears. But with this amp I can plug my grado's in. Detail is first rate but not at the expense of warmth. Up until now I used the grace 901 amp for headphone duties as it has multiple digital inputs as well as a dac section. Also it has dual headphone outputs. The Wna is a simple is a single line in and single headphone out. But the sound quality is much better than the grace 901.

 Pinkfloyd was a bit apprehensive in building a WNA amp for me becuase of the source I have. That it would be outclassed. You are right pinkiedude. My ML combo is outclassed by the WNA. 
	

	
	
		
		

		
		
	


	




 IMO it is better than the GSP solo, it is better than the Sugden headmaster, it is better than my grace 901. But is it the best overall? The Earmax pro is best amp I have owned. Some amps have more detail, bass, timing whatever. But to me it has warmth and naturalness that no other amp I heard can compare to. This amp comes close. The fact that it is a SS amp as well come as a shock. It has better bass, pace and punch. But for obvious reasons it can not produce the warmth of the EMP. But it cost less than the EMP. So I think it deserves joint 1st place with my EMP.

 But this is only the beginning. I think with a better power supply their would be a slight improvement in sound quality. How much I won't know until I order one. Also hopefully in a few months time pinkie will be able to add a second line input and second headphone output. Permitting time and case size restrictions.

 These are my initial impressions. My ML combo is firing on all cylinders with the WNA amp. This amp suits me because of its warm presentation when combined with my ML. Ususally most amps are neutral or bright sounding. Just wait till I try it with my PS-1's and sony R-10's....

 [size=xx-large]Mark Levinson no 31 reference transport/no 30.5 reference dac+WNA amp (pinkie powered) Salutes you[/size], 
 Pinkdude


----------



## PinkFloyd

Quote:


  Originally Posted by *GoRedwings19* 
_
 This is the best SS amp I have heard. It is a well known fact I love tube amps more for the warmth and lushness. But this amp is almost there. It really works well with the senn hd600's but you have to crank it up to 11.00 posistion to really get it going. But with the grado's RS-1's it is totally sweet. As far as SS amps go this is a warm amp._

 

Glad you like it Mike! I think I mentioned that £150 is an insanely good price for an amp that delivers so much quality to your ears now I think you know what I mean't 
	

	
	
		
		

		
		
	


	




 I wouldn't describe the WNA as warm but it certainly isn't spitty and harsh like some SS amps so I can see what you mean by warm.... to my ears it's pretty neutral and doesn't suffer from colouration, I haven't heard it with RS-1's so maybe it is warm with them and that can only be good news for RS-1 owners 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *GoRedwings19* 
_I use to have a GSP solo amp+PSU1. This was great with the hd600's and the rare hp-1000 series headphones. But I didn't use them with the rest of my grado's as the resulting sound was too bright and painful to my ears. But with this amp I can plug my grado's in. Detail is first rate but not at the expense of warmth. Up until now I used the grace 901 amp for headphone duties as it has multiple digital inputs as well as a dac section. Also it has dual headphone outputs. The Wna is a simple is a single line in and single headphone out. But the sound quality is much better than the grace 901._

 






  Quote:


  Originally Posted by *GoRedwings19* 
_Pinkfloyd was a bit apprehensive in building a WNA amp for me becuase of the source I have. That it would be outclassed. You are right pinkiedude. My ML combo is outclassed by the WNA. 
	

	
	
		
		

		
		
	


	


_

 

It's not so much that Mike, I rarely build amps for people and when I do it's for parts cost only (Many ask but there are few who recieve.....You're a diamond geezer Mike so I couldn't say no to you
 ) and I don't charge a build fee my only apprehension was finding the inclination and time to build another one... luckily I wanted to give my new soldering iron a workout 
	

	
	
		
		

		
		
	


	




 It's a top class amplifier and there's no reason it shouldn't compliment the Levinson combo admirably 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *GoRedwings19* 
_IMO it is better than the GSP solo, it is better than the Sugden headmaster, it is better than my grace 901. But is it the best overall? The Earmax pro is best amp I have owned. Some amps have more detail, bass, timing whatever. But to me it has warmth and naturalness that no other amp I heard can compare to. This amp comes close. The fact that it is a SS amp as well come as a shock. It has better bass, pace and punch. But for obvious reasons it can not produce the warmth of the EMP. But it cost less than the EMP. So I think it deserves joint 1st place with my EMP._

 

The WNA is a cracker of that there's no doubt at all..... wait till she burns in there's more to come..... lots more 
	

	
	
		
		

		
		
	


	





  Quote:


  Originally Posted by *GoRedwings19* 
_But this is only the beginning. I think with a better power supply their would be a slight improvement in sound quality. How much I won't know until I order one. Also hopefully in a few months time pinkie will be able to add a second line input and second headphone output. Permitting time and case size restrictions._

 

The PSU I supplied with the amp is a get you going regulated wallwart... others have reported the amp opens up a lot more with a better quality linear PSU and Captain notices a big difference with the WNA cascode PSU (I haven't tried it yet) David also supplies a battery pack PSU which he says brings about further improvements.... live with the wallwart for a while and then try something better, your ears will be used to the intricacies of the WNA by then and you'll be better placed to hear the subtle improvements a better PSU can bring about.

  Quote:


  Originally Posted by *GoRedwings19* 
_These are my initial impressions. My ML combo is firing on all cylinders with the WNA amp. This amp suits me because of its warm presentation when combined with my ML. Ususally most amps are neutral or bright sounding. Just wait till I try it with my PS-1's and sony R-10's...._

 

Look forward to hearing your impressions once the amp is fully burnt in Mike, it gets even better trust me 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *GoRedwings19* 
_[size=xx-large]Mark Levinson no 31 reference transport/no 30.5 reference dac+WNA amp (pinkie powered) Salutes you[/size], 
 Pinkdude 
	

	
	
		
		

		
		
	


	






































_

 

Cheers!


----------



## null

Oh no! Pinkie, I'm so tempted now to order a kit! Should I!? Should I!?

 (EDIT) Is it hard to complete Pinkie?


----------



## GoRedwings19

pinkfloyd>I have been spending more time with the amp. I went to bed at 10.am after listening to the amp with rs-1's for 8 hours solid. I was in work for 11.30am!!!!

 What is the burn in time approx?



 Warm/neutral in this system it is warm. I think I can increase this if I change the interconnect I am using. I use SPM reference at the moment which is well known for being slightly forward. If I try connecting this via Red Dawn instead I might be able to squeeze a little more warmth out of it. 
	

	
	
		
		

		
		
	


	




 As for the wallwart. It will do for now. I will see if anyone will lend me a better one and see if their are significant improvements. I wish I kept the GSP solo PSU1 so that I could compare. But even now the amp is totally sweet to my ears. Let me send the RS_1's anyway so You can see for yourself what I get to listen to everynight. It really perform well with the rs-1's. I haven't tried my other grado's as I have lent most of them out.

 Thank you for giving me a chance to hear and own one of these amps. I will post more impressions later.


----------



## PinkFloyd

Quote:


  Originally Posted by *GoRedwings19* 
_pinkfloyd>I have been spending more time with the amp. I went to bed at 10.am after listening to the amp with rs-1's for 8 hours solid. I was in work for 11.30am!!!!_

 

Whoah, 8 hours is a long session indeed 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *GoRedwings19* 
_ What is the burn in time approx?_

 

There's no hard and fast period Mike and some people even reckon there's no such thing as burn in but I always find an amp opens out in all departments after about 200 - 500 hrs playtime.... here are a few bits about burn in  with the Chiarra which may be worth reading.

  Quote:


  Originally Posted by *GoRedwings19* 
_Warm/neutral in this system it is warm. I think I can increase this if I change the interconnect I am using. I use SPM reference at the moment which is well known for being slightly forward. If I try connecting this via Red Dawn instead I might be able to squeeze a little more warmth out of it. 
	

	
	
		
		

		
		
	


	


_

 






  Quote:


  Originally Posted by *GoRedwings19* 
_As for the wallwart. It will do for now. I will see if anyone will lend me a better one and see if their are significant improvements. I wish I kept the GSP solo PSU1 so that I could compare. But even now the amp is totally sweet to my ears. Let me send the RS_1's anyway so You can see for yourself what I get to listen to everynight. It really perform well with the rs-1's. I haven't tried my other grado's as I have lent most of them out._

 

The Calex open frame PSU I use isn't at all bad and may be worth considering at a later date, I personally found the difference between it and the regulated wart "subtle" and nothing leapt out and grabbed me by the balls _but _ after prolonged listening with the Calex you do pick up on subtle nuances that were missing with the wallwart.

  Quote:


  Originally Posted by *GoRedwings19* 
_Thank you for giving me a chance to hear and own one of these amps. I will post more impressions later._

 

My pleasure Mike I enjoyed making it and I'm really glad you like it


----------



## GoRedwings19

I have clocked quite a few hours with the WNA now and starting to get a feel for it. I have notice the sound begins to open up when you go past the eight o'clock posistion. You seem to gain more detail, more depth. Does anyone else find this?

 With this amp I see no reason why it can't be matched with high end sources and headphones. It is more than a match for the current solid state amps in todays market. The fact it cost so little and if you are a DIY'er makes it a no-brainer.

 I think with a better PSU the decay rates of notes and instruments would be delayed. I like to listen to live accoustic sets and have noticed compared to the EMP and EMP anniv. The decay rates are less than them. Although tubes might have a big part to play in this. This with a better power supply I believe would give a fuller sound. Anyone like to comment on better PSU's with the WNA?


----------



## 1UP

IRO the sound filling out, could this be a function of the gain? Does increasing gain flesh the sound out more? How should gain be set ideally?


----------



## PinkFloyd

Quote:


  Originally Posted by *1UP* 
_IRO the sound filling out, could this be a function of the gain? Does increasing gain flesh the sound out more? How should gain be set ideally?_

 


 The standard gain of the WNA is 4.3 and is pretty spot on IMO.

 Gain is like a little volume control. You don't want the volume level to get loud too quickly as you wont have good control as music levels differ. You also don't want to have to turn it up all the way to get loud either, since different music may be recorded at different levels so if you set the gain for max output with one music source it might not get loud with a music source recorded at a lesser level.

 I upped the gain to 6 and it was just a bit too immediate for me (ie: the sound gets louder at a lower volume setting) I think 4.3 is optimum unless you want loud music at a lower volume setting in which case you increase the gain to suit your ears.

 To increase the gain to 6 replace R3 (3k3R) with a 4k7 resistor... as previously mentioned altering the gain will not alter the sound in any way at all.

 Hope this helps.


----------



## PinkFloyd

It may be of interest to WNA builders to learn that Dr. White now provides a little PCB that converts the WNA headamp inputs from single ended to balanced. Its only 49x57mm and it can be powered from P4 on the headamp. He says there Should be plenty of room for the PCB pcb and xlr ( balanced ) connectors into the Hammond case that a few of us use.

 I'll find out the price of the PCB and also the price of a balanced "add on kit" and report back..... looking good tho 

 Mike.


----------



## PinkFloyd

Quote:


  Originally Posted by *GoRedwings19* 
_I have clocked quite a few hours with the WNA now and starting to get a feel for it. I have notice the sound begins to open up when you go past the eight o'clock posistion. You seem to gain more detail, more depth. Does anyone else find this?
_

 

Eight o'clock position is pretty low Mike, you will find it opens up a bit more after 8 o'clock yes... if you want more "grunt" at the 8am position then the gain can be upped slightly to give you more volume at a lower volume control setting..... no probs but, as I said above, the gain setting of 4.3 is pretty spot on..... try some heavy metal or electro at 8am and you'll see what I mean.

 All the best.

 Mike.


----------



## 1UP

Thanks, Mike, yes that explanation really helps. Begs the following questions, though: is it possible to set a gain of 5 or 5.x? What clock-position is your volume knob when listening to rock music at a comfortably enjoyable volume level? 

 I find I need to get to between 12 and 1 o'clock with my DT990s.


----------



## GoRedwings19

Quote:


  Originally Posted by *PinkFloyd* 
_Eight o'clock position is pretty low Mike, you will find it opens up a bit more after 8 o'clock yes... if you want more "grunt" at the 8am position then the gain can be upped slightly to give you more volume at a lower volume control setting..... no probs but, as I said above, the gain setting of 4.3 is pretty spot on..... try some heavy metal or electro at 8am and you'll see what I mean.

 All the best.

 Mike._

 

The gain you set is perfect. I have no problem with it. I find I just keeping turning up the volume when I use the RS-1's with it. I have never found a SS amp I have liked with the RS-1's until now.

 The balanced inputs interest me. I have only one rca input would like to have the balanced modification without sacrificing the rca input. Would it be possible to put a little switch on the front so I could select between the inputs. The reason I enquire about this mod is because my ML can run in full differential mode therefore squeezing more performance out of it. The WNA is up to the job I feel.


----------



## PinkFloyd

Quote:


  Originally Posted by *1UP* 
_Thanks, Mike, yes that explanation really helps. Begs the following questions, though: is it possible to set a gain of 5 or 5.x? What clock-position is your volume knob when listening to rock music at a comfortably enjoyable volume level? 

 I find I need to get to between 12 and 1 o'clock with my DT990s._

 

The DT-990 is a pretty hard phone to drive from all accounts so you may want to do two things:

 1: Up the quiscient current by 20% this will give the amp a bit more grunt. To do this remove the four 10 ohm resistors (R7 & R8) and replace them with four 8 ohm resistors. If you do this ensure you fit heatsinks onto TR1 and TR2 as they will give off more heat which needs dissipated... having said that I've got my amp running with 8 ohm resistors in R7 & R8 and the transistors (TR1 & TR2) don't get too hot without sinks but to be on the safe side fit clip on heatsinks to TR1 & TR2 if they are not already fitted.

 2: Up the gain to six. This will ensure that your comfortable listening level is dropped down from 12 o'clock to around 10 o'clock on the volume control. To adjust the gain to 6 remove the 3.3K resistors (R3) from both channels.. fit 4.7K resistors in their place and that will give you a gain of around six.

 You can experiment with the gain and there are no rules written in stone, adjust it until you find a volume control setting your ears are comfortable with.

 Gain is calculated thus:

 G=(1+R3/R2)

 In the stock guise:

 R2 = 1K
 R3 = 3.3K

 So: 1 + 3.3 divided by 1 = 4.3 gain

 Here's another example:

 R2= 1K
 R3 = 5K 

 So: 1 + 5 divided by 1 = 6 gain (1 plus 5K divided by 1K = 6)

 Always calculate using 1 + the value of R3 and divide it by the value of R2 that will give you the gain.

 Hope this helps.

 All the best

 Mike.

 EDIT: My comfortable listening level with HD-600's is 9 o'clock postion if I went up to 12 o'clock it would be a lot louder.


----------



## individual6891

Does anyone have any pics of the plug-top power supply's specs? Or of the supply itself? How's the power supply with regulation? LM317 regulated outputs?


----------



## PinkFloyd

Quote:


  Originally Posted by *individual6891* 
_Does anyone have any pics of the plug-top power supply's specs? Or of the supply itself? How's the power supply with regulation? LM317 regulated outputs?_

 

I believe David supplies the FRIWO switched mode power supply with the kit amp... it can be used in any country and is supplied as a "get you going" PSU if he were to provide an exotic PSU with the kit the price of the kit would surely double. I've never heard the WNA with the FRIWO but according to David it is surprisingly good!

Details of the FRIWO here







 The starter PSU I use is the regulated Stontronics PSU but it's really only suitable for UK users as it comes with 3 pin connection as standard... details of the Stontronic PSU here


----------



## PinkFloyd

Quote:


  Originally Posted by *null* 
_Oh no! Pinkie, I'm so tempted now to order a kit! Should I!? Should I!?

 (EDIT) Is it hard to complete Pinkie?_

 

Hi Null,

 Question is do you need an amp, are you up to building a kit amp? If you answered yes to both then you should!!


----------



## PinkFloyd

It's just come to my attention that there is a *major * upgrade to this superb amp taking place and I will announce it as soon as I can in a new "WNA PCB1 PCB2" thread shortly as soon as I have evaluated the latest revisions ........... This is looking VERY promising indeed.


 Mike.


----------



## damitamit




----------



## PinkFloyd

I hope Dr. White doesn't mind me leaking this:

 "There was never going to be a good time to do this but there are now two new versions of the WNA headphone amp 
	

	
	
		
		

		
		
	


	




 The first version ( type 1 pcb ) is similar to the previous one except the pcb is a little larger; there are now two pairs of output devices per channel to deliver more grunt into low impedance headphones; 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 price for the kit is now £160 and the assembled and tested version is £210. The case is the same as previously but the pcb mounting holes will be in different positions.

 The second version ( type 2 pcb ) is as for the first (pcb1) except that the pcb is larger again because the volume control and headphone jack now mount on the pcb - which can still be shoehorned into the standard case.

 I'm thinking of offering this pcb in a kit with a high quality case. I have a prototype built into a very substantial heatsink case but nothing is cast in stone at present. If I went ahead with this prices are likely to be £200 for the kit and £270 for the assembled and tested version.


 I realise this is tough on people who have already bought headphone amps, particularly those who have purchased recently. So to lessen the pain I will offer existing owners type 1 pcbs for £15; or a type 1 pcb plus the extra parts necessary to implement the new design for £25. This assumes that you desolder and reuse all of the components on your old pcb. 

 I can also upgrade assembled and tested units to the new standard but this isn't going to be as cost effective because of the labour involved. If anyone is interested in this option they should contact me directly.


 You can post all of the above if you want. 

 Regards, David"


 Looking GOOD more details to come as soon as I get them


----------



## Alick

When??? I feel a new build coming on ...


----------



## aeriyn

In reading some of tangent's papers on opamps, I read a bit on the LM6171. Do you feel that the LM6171 presents enough of a sound quality increase as opposed to something like the AD8610, which by virtue of being an FET input opamp is easier to work with?

 I gathered from tangent's writing that the LM6171 wasn't in the same quality class as the AD8610 and OPA637, etc.

 And this is totally unscientific and subjective, but what kind of sound does the LM6171 have? Is it mellow or lively?

 What brand of film caps does the WNA use as its output caps?


----------



## 1UP

Sorry, I'm not clear what the benefits of the second PCB option are - is it cosmetic, solely down to a new nicer enclosure? Or are their sonic benefits, too?


----------



## Alick

Off the top of my head (I've seen neither of the new boards); as the volume pot and headphone jack mount on the board, there are a few advantages:

 1. Easier assembly (no need for headphone and volume control hook up wire and no danger of incorrect connections to pot or socket).
 2. Signal routing intergrity is fixed and does not depend on cable quality/length/route.
 3. Fewer solder joints in signal path. Hook up wire needs a solder joint at each end. Eliminating the wire eliminates one solder joint per connection, 9 in total if my arithmetic is correct.
 4. Allows for more front panel options; you don't have to use panel mounting nuts as the PCB solder joints provide alternative fixing points.

 Downsides include:
 1. May restrict choice of pot and socket to those which physically fit the PCB location (although you can still use flying leads but would then be better with PCB 1)
 2. If you drill your own front panel, you'll have to be much more accurate with the pot and socket hole locations with respect to each other and the PCB mounting holes on the base.
 3. More difficult to upgrade to a stepped attenuator (though not impossible).

 Are the input sockets and DC power socket PCB mounted too?


----------



## Syzygies

Quote:


  Originally Posted by *PinkFloyd* 
_and each channel is now completely independent ( i.e. the amp is dual mono ) so that you can have one power supply per channel. _

 

This question has come up several times recently elsewhere, but I haven't seen it answered. Apparently, some dual mono designs don't mind being used with shared ground headphones, and some do.

 My read of the above is that WNA isn't forcing everyone to rewire all their phones, they're ok with tying the grounds at output.

 Can anyone explain the salient differences in amp design that allow some dual mono amps to tolerate shared output grounds, with others explicitly warning against this? What is the WNA choice that allows this?

 In shared "ground channel" amps like the Pimeta and the PPA, the ground channel doesn't use a feedback loop that looks anything like the signal channels. It looks to me like the signal channel feedback loops would fight each other, sounding ok but wasting current, if one plugged a mono jack into the output, tying together the two signal outputs. In a true balanced dual mono amp, wouldn't the same thing happen with shared ground headphones?

 Maybe what some people mean by "dual mono" is separate ground channels, each like the single Pimeta and PPA ground channel, allowing the grounds to be tied on output. And "balanced dual mono" means identical feedback loops on both signal and ground, for a design that's grumpy when the grounds are tied on output?

 Am I missing something here? To recap, I've heard both answers to *"Can you tie grounds on a dual mono amp?"*, I believe both answers apply to their respective amps, and I don't understand why.


----------



## Alick

My reading of Mike's post makes me tend to believe that the signal grounds will be tied together at the headphone socket. I'm sure Mike or David will explain shortly.


----------



## PinkFloyd

Quote:


  Originally Posted by *Syzygies* 
_This question has come up several times recently elsewhere, but I haven't seen it answered. Apparently, some dual mono designs don't mind being used with shared ground headphones, and some do.

 My read of the above is that WNA isn't forcing everyone to rewire all their phones, they're ok with tying the grounds at output.

 Can anyone explain the salient differences in amp design that allow some dual mono amps to tolerate shared output grounds, with others explicitly warning against this? What is the WNA choice that allows this?

 In shared "ground channel" amps like the Pimeta and the PPA, the ground channel doesn't use a feedback loop that looks anything like the signal channels. It looks to me like the signal channel feedback loops would fight each other, sounding ok but wasting current, if one plugged a mono jack into the output, tying together the two signal outputs. In a true balanced dual mono amp, wouldn't the same thing happen with shared ground headphones?

 Maybe what some people mean by "dual mono" is separate ground channels, each like the single Pimeta and PPA ground channel, allowing the grounds to be tied on output. And "balanced dual mono" means identical feedback loops on both signal and ground, for a design that's grumpy when the grounds are tied on output?

 Am I missing something here? To recap, I've heard both answers to *"Can you tie grounds on a dual mono amp?"*, I believe both answers apply to their respective amps, and I don't understand why._

 






 Good question.

 I'm not in a position to answer it as I haven't got a clue what the new boards entail but I posed your question to Dr. White and here is the reply I received:

 "If you've tied the earths ( grounds ) together at the output or used a jack socket with the mounting bush in contact with the jack sleeve, AND the phono input sockets are bolted directly to a metal case then you've made a tight earth loop which will cause problems with hum and noise under some circumstances. I have Never had any problems with the WNA amps ( which all have a shared output earth ) although as far as I can see most people use insulated phonos and insulated headphone jacks and the case is earthed at one point only. The new amp is no different from the old ( which was dual mono except for a shared power connection ) in this respect. So you just use your headphones in the same way as you did with the older version. Dual mono to me means that each amplifier channel is electrically and physically separate with no shared components.

 The Pimeta and PPA use a shared active virtual earth ( driven by the third channel ) isolated from the real earth which solve this problem comprehensively. With careful pcb layout and sensible wiring up the active virtual earth shouldn't be necessary but it does provide an insurance policy against unintended sloppiness. Whether there are other advantages to an active virtual earth or whether it benefits the sound I couldn't comment on at this point.


 There are three ways of driving headphones. (1) Two amplifier channels with a shared real earth return (2) Three amplifier channels one of which serves as a shared active virtual earth and (3) Four amplifier channels providing a differential output with no output earth. Methods (1) and (2) don't require you to modify your headphones, but method (3) usually involves cutting off the headphone jack and replacing it with a 4 pin connector of some kind ( xlrs are popular ). If your headphone lead is 3 rather than 4 wire ( the majority ) then you need to make up a new headphone lead. With Senn HD600s or 650s for example you just need to cut off the jack and replace it with a 4 pin xlr. I made up a new lead for my Senn HD600s so that I could replace the existing wire with decent silver plated, ptfe insulated wires which are shielded with a silver plated copper braid. Balanced headphone amps completely isolate each channel ( no shared earths either virtual or real ) and sound better to most people who've tried it. But its quite an expensive route to go down."


 I trust Dr. White's reply helps you 
	

	
	
		
		

		
		
	


	




 All the best.

 Mike.


----------



## Syzygies

Thanks!

 What I read into his answer is that he isn't using balanced mono _or_ ground channels in his design. He sets up two independent circuits starting with separate power sections, but he allows you to tie the grounds together when you plug in your earphones.

 This of course forces an interaction between the power supplies, they are no longer truly independent, but my "feedback loop" concerns are irrelevant, the feedback loops are separated from ground by the impedance of the headphones.

 Unless someone else wants to weigh in, I guess I have to stare at some circuits to figure out my question completely.


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## Nick Case

Hello All

 Having read all this post over the last 8 weeks or so I ordered a kit from David just before Christmas 
	

	
	
		
		

		
			





 Build is now finished in a Hammond case. All seems to be fine until I hook it up to a source, at which point the led winks out and I can hear a squealing from the amp (this is without cans plugged in!) 
	

	
	
		
		

		
		
	


	




 Have I angered the oscillation god with my use of a DIN socket for the signal input?

 Anyone else had problems hooking WNAHA to Naim? 

 The naim system I use is of course all DIN with a common signal OV for each channel. This common signal OV is connected to ground within the CD source so that everywhere in the system the OV is actually ground proper.

 Without any connection into the DIN socket on the amp it sits there quite happily. Looks pretty and all that but a bit useless realy. I could ditch the DIN socket and wire up a DIN - RCA cable and replace the DIN socket with RCAs. I'd prefer not to as the holes are drilled on the case.

 Whats going on here 
	

	
	
		
		

		
		
	


	




 All help very much appreciated.


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## Alick

Nick; I suspect that you have grounded one side of the DC supply which is supposed to float. That it only fails when you plug in the DIN plug leads me to believe that you have connected the ground pin on the DIN to one side of the DC supply which is a no-no with the WNA. Using a DIN input socket should be fine; just make sure that you are not earthing the supply DC anywhere in your wiring scheme. I hope this helps.

 EDIT: Things to check:
 1. The wiring from the DC supply should go to the PCB (via a switch if you have one fitted) AND NOWHERE ELSE.
 2. No side of the DC supply should be grounded from the PCB or anywhere else.
 3. The PSU you are using should not have a grounded 0V line.
 4. Both sides of the DC input socket should be isolated from the case.

 If you have a DMM: with the amp and source powered down, check for continuity between the 0V pin of the DIN input socket and the DC supply 0V line with the DIN plug both in and out. There should be no continuity either way.


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## Nick Case

Thanks Alick

 I do indeed have continuity between DC -ve and case/signal OV 
	

	
	
		
		

		
		
	


	










 This only appears when I plug the DC supply in and turn the switch on. Of course I can then see the problem as once connect the DIN connector to the pre/source then the DC -ve is grounded!

 The supply only arrived this morning (via a special "I'm realy keen to get listening to some tunes" high cost Saturday delivery) It is a Stontronics Desktop 24v Switched Model EPA-201D-24. Which I thought would be floating surely! 

 I've just checked the PSU and I get continuity between the DC -ve and DC +ve and the earth pin on the mains!

 Have I bought the wrong supply or is it faulty (it gives a nice steady 24.1VDC across output). Should have just got the WalWart from David.

 Bugger how do I ensure I order a floating PSU guys? 

 Cheers Nick


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## aeriyn

Quote:


  Originally Posted by *Nick Case* 
_Bugger how do I ensure I order a floating PSU guys?_

 

Order a 24V Elpac PSU. They are linear isolated and work very well.


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## Nick Case

The problem was definitely the non-floating PSU.

 I found an old 12V unregulated walwart which is so bad it actually provides 19V! 

 It does give me sound 
	

	
	
		
		

		
		
	


	




 enough so I can verify integrity of build. Naturally with a low unregulated voltage and no-burn in time I find the sound very average but I am looking forward to the improvements burn in and a proper supply will bring. 

 This may not be the right thread (or even forum) but can anyone advise if the WNA can be adapted to work with non-floating PSU or if the PSU's can be converted at all. I ask because I have some quite excellent 24V supply around which I am keen to employ.

 Thanks Again.

 Nick


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## Alick

I use a different Stontronics model (as do many WNA builders) which was recommended by Mike; it's an AD-2400400RBS (Rapid Part No. 85-1746) which costs £7.95 + VAT and delivery. Rapid live up to their name where delivery is concerned, so you could order one and have it by Tuesday or Wednesday with a bit of luck.

 I'm not sure if it's wise to modify the PSU you have. You could disconnect the earth connection from the mains plug or open the supply and remove the connection from the mains earth to the DC side, but neither course is advisable. As the PSU has an earth connection, it's probably not double insulated. Therefore, if anything goes wrong, there's the remote possibility of mains voltages being presented to a device which you have clamped across your ears! 

 Also, some people advise against using switched mode PSU's for audio equipment (I suspect the model you bought is switched mode) as they have the potential to generate electrical noise but I don't know how real the problem is.


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## PinkFloyd

Quote:


  Originally Posted by *Syzygies* 
_Thanks!

 What I read into his answer is that he isn't using balanced mono or ground channels in his design. He sets up two independent circuits starting with separate power sections, but he allows you to tie the grounds together when you plug in your earphones.

 This of course forces an interaction between the power supplies, they are no longer truly independent, but my "feedback loop" concerns are irrelevant, the feedback loops are separated from ground by the impedance of the headphones.

 Unless someone else wants to weigh in, I guess I have to stare at some circuits to figure out my question completely._

 

A bit more on this from David:

 " If you used separate power supplies with a standard WNA headphone amp, a 4 pin output connector ( i.e. separate output earths for each channel ), kept all signal earths for each channel separate, and rewired your headphones as for balanced use, then you could have two completely independent amplifier channels, one driving each earpiece. This will undoubtedly be better than using a standard output jack, which forces you to use a shared earth, with the attendant consequences of ( small but real ) channel interaction. Certainly using separate power supplies for each channel gives you some sonic benefit, but I don't know at this point how much extra benefit you get from using a 4 wire headphone connection with single ended amplifier channels. I presume there must be some noticeable improvement in sound quality and that this is why you are warned against joining the output earths together with systems which have two truly independent amplifier channels - you'd lose some of the benefits of such a system if you did this."


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## PinkFloyd

Quote:


  Originally Posted by *Alick* 
_When??? I feel a new build coming on ... 
	

	
	
		
		

		
		
	


	


_

 

The new boards are available now 
	

	
	
		
		

		
		
	


	




 I'll be trying the PCB2 shortly and will post pics and details as soon as I populate the board. The DC input and phono inputs still have to be wired to the board as there are a lot of different DC supply options on the board and I believe you have to do some jumpering on the underside of the board dependant on which type of power supply you use...... the upside is the board is now a lot more versatile and the pot and headphone socket are board mounted which means 9 less solder joints and does away with quite a lot of wiring.

 I will report back shortly.

 Mike.


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## rickcr42

Quote:


 Certainly using separate power supplies for each channel gives you some sonic benefit, but I don't know at this point how much extra benefit you get from using a 4 wire headphone connection with single ended amplifier channels. I presume there must be some noticeable improvement in sound quality and that this is why you are warned against joining the output earths together with systems which have two truly independent amplifier channels - you'd lose some of the benefits of such a system if you did this." 
 

i have in the past done "dual mono" to the point of actaully using a stereo amp for _each _ channel and out of neccesity used a fur conductor phone jack (amphenol part i think it was).
 Any contact betwen the two channels or either polrity and ground when attached to a true balanced bridge output is a dead short so the headphones also had to be modified for dual mono use.
 i then compared this "overkill' amp to the original _shared ground normal stereo amp_ and i could not say it sounded any better even after all the extra work.

 I have also done the dual mono power supplies thing and and while there is a _measurable_ stereo separation increase i think for headphone use (actually even speaker use where the room mixes the two channels anyway) this is coming at it for me personally "backwards" considering i use a crossfeed circuit !
 What is gained by dual mono up to the jack is dynamics and power.Each channel is free to draw as much current as it needs without sapping power from the other channel .

 This is a thing i no longer do due to added cost and complexity but instead just overbuild a single supply for current headroom and then use "decoupling networks" to semi-isolate the two channels for a "quasi-dual-mono" design.

 The dual mono option is not cheap when you consider where the cost is in any amplifiers-the supply-but i would not argue against anyone doing it.(dual mono supplies and shared ground at the jack that is,i would not do FULL dual mono amp/cans again)


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## individual6891

What model is the Hammond case you originally use in your first few posts to enclose the PCB? (I mean the smaller version of the Hammond, not the larger one that you use in your later threads)


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## PinkFloyd

Quote:


  Originally Posted by *aeriyn* 
_In reading some of tangent's papers on opamps, I read a bit on the LM6171. Do you feel that the LM6171 presents enough of a sound quality increase as opposed to something like the AD8610, which by virtue of being an FET input opamp is easier to work with?_

 

Yes, without a shadow of a doubt. In the WNA the LM6171 is miles ahead of the AD-8610 / AD-8065 even "with" output caps fitted. I've tried most of the popular opamps in the WNA and the LM6171 is a "clear" winner to my ears. 

  Quote:


  Originally Posted by *aeriyn* 
_I gathered from tangent's writing that the LM6171 wasn't in the same quality class as the AD8610 and OPA637, etc._

 

The same quality class? It's cheaper than AD8610 and OPA637 and if you design the amp around the LM6171 you will get better results with LM6171.... as a drop in replacement the LM6171 is a prima donna and can cause a lot of hassle but if the amp is designed around it then it's a sonic marvel IMO. 

  Quote:


  Originally Posted by *aeriyn* 
_And this is totally unscientific and subjective, but what kind of sound does the LM6171 have? Is it mellow or lively?_

 

Natural / Neutral.

  Quote:


  Originally Posted by *aeriyn* 
_What brand of film caps does the WNA use as its output caps?_

 

The stock WNA kit comes with Nitai bipolar output caps (220uF) the amp sounds great with them. I, personally, use electrolytic ALCAP non polar output caps (probably out of habit) I have always found the ALCAPS to sound more organic in loudspeaker crossover circuits than Solen or Hovland musicaps but I'm in a majority of one when it comes to preferring electrolytics over polyprops....... it's a matter of taste aeriyn, use your ears when it comes to selecting a capacitor as they all display certain sonic characteristics and only your ears can tell you what brand / type is best for your ears.

 David's experience and ears are spot on with the Nitai caps as they are very Neutral and therefore will suit 98% of listeners..... if you want a touch more grain and organicity then try ALCAP...... if you want a tad more thrum and plasticity then lean toward the likes of ANSAR supersound caps or Hovland Musicaps but expect to pay a lot for them and be prepared to house them in a seperate enclosure..... a 220uF Hovland Musicap (if you could buy one) would be HUGE and insanely expensive.....


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## rickcr42

Quote:


 Natural / Neutral. 
 

I beleive the first person i know of using this chip as a headphone amp was Tomo.
 he kinda cheated and purchsed the Evaluation board direct then added a supply and jacks and he reported the same thing-natural and nuetral.

 not that i am saying the eval board compares to this kit,

 Many after attempted to design around the chip and ran into big time problems and the reported results mostly were bad.

 Get this bad boy wrong (the 6171) and you get no second chances.You pretty much have to design around the specific chip as pinky said and it is not a good candidate for "opamp rolling" unless you get _really_ lucky .
 Drop in it is not and steps need to be taken to insure proper operation.


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## PinkFloyd

Quote:


  Originally Posted by *individual6891* 
_What model is the Hammond case you originally use in your first few posts to enclose the PCB? (I mean the smaller version of the Hammond, not the larger one that you use in your later threads)_

 


 Either:

 N84AL: Clear anodised (aluminium end panels)
 N76AL: Clear anodised (Black plastic end panels) the one I used.
 N80AL: Black anodised (Black plastic end panels)

 They are all the same size 120 x 78 x 43 and only differ in finish, you can order them here

 There is NO WAY you'll get a RK27 pot into that enclosure and you'll find it a very tight squeeze to fit c2 c4 c6..... only choose that dimension of enclosure if you are confident in your ability to "shoehorn" You've got 1mm free play. 

 All the best.

 Mike.


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## GoRedwings19

I read with great interest about the balanced input module. This module I am very interested in as believe it or not my ML dac has multiple outputs of every connection going but only one unbalanced output. I would like to coonect my WNA via balanced outputs.


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## PinkFloyd

Just to keep you guys updated, I've got a PCB1 and PCB2 on the way and will do a write up on them in a brand new "WNA MKll boards" thread as soon as I've got the hang of the new board layout.

 I'll take pictures of the PCB1, PCB2 and original board and will upload pictures of the boards as they are being populated. I would add the details of the new boards to this thread but it's over 27 pages long as it is so It's better to start an entirely new thread to concentrate on the WNA PCB1 & PCB2.

 I'm sure this thread will remain a valuable resource for owners of the original board and hopefully the input will continue from WNA owners who have questions or tweaks they want to share with fellow WNA'ers.

 All the best.

 Mike.


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## BrokenEnglish

sorry for reactivating this older monster-thread, but my questions are related to the mkI wna ha and i feel no longer comfortable posting them in the mkII-thread.

 today i removed the input caps (c1) and jumpered j1 with 0,6mm² silvered copper wire. i got some serious cracking in the phones, when turning the pot (between ~10-2 o'clock). the recently recommended zobel net still is installed, i also grounded the pot. any ideas? should i use 0-ohm bridges for j1?


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## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_sorry for reactivating this older monster-thread, but my questions are related to the mkI wna ha and i feel no longer comfortable posting them in the mkII-thread.

 today i removed the input caps (c1) and jumpered j1 with 0,6mm² silvered copper wire. i got some serious cracking in the phones, when turning the pot (between ~10-2 o'clock). the recently recommended zobel net still is installed, i also grounded the pot. any ideas? should i use 0-ohm bridges for j1?_

 

Hi Udo,

 Are you totally sure that your source has output caps fitted? I think you should measure the DC offset from your source before removing the input caps on the WNA... if it's zero then fine, there should be no cracks in the phone and it's perfectly good to remove the caps from J1 and replace with wire jumpers..... if there is DC offset keep the caps in place.

 Mike.


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## BrokenEnglish

Quote:


  Originally Posted by *PinkFloyd* 
_Hi Udo,

 Are you totally sure that your source has output caps fitted? I think you should measure the DC offset from your source before removing the input caps on the WNA... if it's zero then fine, there should be no cracks in the phone and it's perfectly good to remove the caps from J1 and replace with wire jumpers..... if there is DC offset keep the caps in place.

 Mike._

 

thanks, mike. i measured dc of my source before: 0,5 mV max; also i know that my (unmodded) emu0404 has output caps; also my second amp don't has input caps. cracking remains with or without signal. output dc = 0mV. i'll try zero ohm bridges now.


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## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_thanks, mike. i measured dc of my source before: 0,5 mV max; also i know that my (unmodded) emu0404 has output caps; also my second amp don't has input caps. cracking remains with or without signal. output dc = 0mV. i'll try zero ohm bridges now._

 


 Hi Udo,

 report back after you try the zero ohm jumpers.

 All the best.

 Mike.


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## BrokenEnglish

no effect with the zer-ohm bridges: cracking starting from ~12 o'clock, slight high pitched hum with max. volume. things are bettered, when i increase the distance from board to case-ground. a sort of oscillation?

 ok.. malefactor detected: my uberized psu! 
	

	
	
		
		

		
			





 ...i'm using an shielded cable from my psu to the amp, that most likely acted as an antenna for rfi. will switch that cable. no probs with my simpler psu. thanks again for your constant attention, mike!


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## PinkFloyd

Quote:


  Originally Posted by *BrokenEnglish* 
_no effect with the zer-ohm bridges: cracking starting from ~12 o'clock, slight high pitched hum with max. volume. things are bettered, when i increase the distance from board to case-ground. a sort of oscillation?

 ok.. malefactor detected: my uberized psu! 
	

	
	
		
		

		
		
	


	




 ...i'm using an shielded cable from my psu to the amp, that most likely acted as an antenna for rfi. will switch that cable. no probs with my simpler psu. thanks again for your constant attention, mike!_

 


 hmm it doesn't seem to like that new PSU for some reason


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## BrokenEnglish

more issues... it's better with the simpler psu, but it's not away: i measure some spikes of output voltage while turning the pot, max. 5mV, that go down to 0mV after few ms with constant pot-position... nothing to worry about, but not good at all... 
	

	
	
		
		

		
		
	


	




 i guess, the lm6171 is still not tamed...

 i rerouted some cabling, increased the pcb-bottom-distance... no effect.

 i also tried upping the qc again and am still not happy with the result: i said, i missed some highs after my first trials... but that's not the truth. after more listening i'd say, there's a sort of drop in the upper mids with more qc. basses seem to be more powerful, but at the expense of poorer resolution. i'll go back to the former values (r5=120, r6=75).

 removing the input caps produced a noticeably clearer sound... really lovely. i'll drop an email to david... maybe he'll find a way for some additional power-rail bypassing or bandwith limiting, as recommended by tangent. i'd definitely prefer to leave the input caps out.

 hm... hmmm... hmmm... 
	

	
	
		
		

		
		
	


	




 ... still love my wna... and i'll get, what i want! i'm just a step away... can feel it...


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