[PinkFloyd]

Quote:

Originally Posted by FritzS Hi, has anyone tested - instead of the non-polar electrolytic caps- two polar 2000uF 25V electrolytics "face to face" (connecting with - pole) and put a resistor 81k to 10 kOHM) from this connection-point to V- So on each cap are ~ 10 V DC

I tested this quite some time ago with 2 x electrolytics connected back to back but the sheer physical size is not practical and there really is no point doing this when non polar capacitors are available to buy.. sure, if you've got truckloads of room in the enclosure and you can't source non polar caps then there's no reason why you can't connect two electrolytics back to back to make a non polar cap. I haven't tried the resistor to V- this sounds like a good idea worth trying.

 

[FritzS]

Hi,
I publish my hearing tests and tuning experience about the WNA and the CD 650 too on my homepage:
http://www.stockhammer.at/hifi/

WNA http://www.stockhammer.at/hifi/wna.php
CD 650 http://www.stockhammer.at/hifi/cd650.php
About hearing please see both

PS: What cinch cables are use you? I use Nichicon KZ on output of the CD 650 - it is a very good cap in signal-line (if a lot of DC voltage stand on it), but it make problems with bad cinch cables! This combination sounds only good with good cables. The CD 650 use NE5532, but I will use AD OP275 (commended in an other forum).

 

[PinkFloyd]

Quote:

Originally Posted by FritzS Hi, I publish my hearing tests and tuning experience about the WNA and the CD 650 too on my homepage: http://www.stockhammer.at/hifi/ WNA http://www.stockhammer.at/hifi/wna.php CD 650 http://www.stockhammer.at/hifi/cd650.php About hearing please see both

Great site Fritz, keep up the good work, very informative indeed a real reference point for WNA owners

I'll be building up a balanced WNA very soon so there will be yet another reference point for this wondeful amp.

[

 

[FritzS]

Quote:

Originally Posted by PinkFloyd I'll be building up a balanced WNA very soon so there will be yet another reference point for this wondeful amp. [

Next time I will write a list with all my ideas, improvements, suggestions, wishes about WNA MK III - and I have a lot of them

 

[PinkFloyd]

Quote:

Originally Posted by FritzS Next time I will write a list with all my ideas, improvements, suggestions, wishes about WNA MK III - and I have a lot of them

Go for it Fritz! The more suggestions and ideas the better, you can never have too much of a good thing... go for it man, the floor is yours......

 

[FritzS]

Quote:

Originally Posted by PinkFloyd Go for it Fritz! The more suggestions and ideas the better, you can never have too much of a good thing... go for it man, the floor is yours......

My first suggestions

Other output transistors:
BD138/139 -> Toshiba 2SC2238 / 2SA968 or 2SA1837 / 2SC4793
BD138/139 -> BD238/239

C2/C3, C8/C9/C10 -> additional holes in PCB – it gives some caps with other lead distance … use 5 mm, 10 mm, 15 mm too

C1 -> additional holes in PCB – it gives some caps with other lead distance … use 27,50 mm, 37,50 mm – for WIMA MKP 10 + additional holes for bypass caps – MKP, FKP use 5 mm, 10 mm, 15 mm

C6 -> more place for Black Gates + additional holes for bypass caps!

R11 -> place for a 1W resistor – additional holes ……

Place around the electrolytic caps (fore “bigger” ones) + additional holes for bypass caps (extra PSU decoupling)!

Use copper lines (with wire bridges) on PCB in place of the additional wiring – between output caps and headphone jack
between rail-splitter and amplifiers
between C1 and cinch connector – on PCB ….

Headphone DC protection as supplement on PCB!?

Additional input switch for more than one source + outgoing jack – to use WNA MKIII as preamp too!

Zobel Filter – place on PCB (holes, solder -eye)

Offset trim-potentiometer – place on PCB – likely for other OP’s too

Schema for rail-splitter looks like as the amp ….. Class A too + option dual rail splitter

330 kOHM tantalum place on PCB (holes, solder-eye) too

Other mounting for headphone jack or other type ….

Bigger case ....

more about - in some days

 

[PinkFloyd]

Quote:

Originally Posted by FritzS My first suggestions Other output transistors: BD138/139 -> Toshiba 2SC2238 / 2SA968 or 2SA1837 / 2SC4793 BD138/139 -> BD238/239 C2/C3, C8/C9/C10 -> additional holes in PCB – it gives some caps with other lead distance … use 5 mm, 10 mm, 15 mm too C1 -> additional holes in PCB – it gives some caps with other lead distance … use 27,50 mm, 37,50 mm – for WIMA MKP 10 + additional holes for bypass caps – MKP, FKP use 5 mm, 10 mm, 15 mm C6 -> more place for Black Gates + additional holes for bypass caps! R11 -> place for a 1W resistor – additional holes …… Place around the electrolytic caps (fore “bigger” ones) + additional holes for bypass caps (extra PSU decoupling)! Use copper lines (with wire bridges) on PCB in place of the additional wiring – between output caps and headphone jack between rail-splitter and amplifiers between C1 and cinch connector – on PCB …. Headphone DC protection as supplement on PCB!? Additional input switch for more than one source + outgoing jack – to use WNA MKIII as preamp too! Zobel Filter – place on PCB (holes, solder -eye) Offset trim-potentiometer – place on PCB – likely for other OP’s too Schema for rail-splitter looks like as the amp ….. Class A too + option dual rail splitter 330 kOHM tantalum place on PCB (holes, solder-eye) too Other mounting for headphone jack or other type …. Bigger case .... more about - in some days

So, in effect, a different amp!! I totally agree with you regarding the tracks for the rail splitter to amp, more room for bigger caps, bigger holes all round (especially to accomodate quality signal cables) a bit more space on the board, bigger board that will slot into a Hammond and a head socket that actually fits on the board or bigger holes for the headsocket.

Mike.

 

[FritzS]

Quote:

Originally Posted by PinkFloyd So, in effect, a different amp!! I totally agree with you regarding the tracks for the rail splitter to amp, more room for bigger caps, bigger holes all round (especially to accomodate quality signal cables) a bit more space on the board, bigger board that will slot into a Hammond and a head socket that actually fits on the board or bigger holes for the headsocket. Mike.

What think you about a modified buffer - looks like as
http://www6.head-fi.org/forums/showp...9&postcount=18
..... transistors on place of the diodes?

or the complete "diamond buffer"
http://www.elecdesign.com/Globals/Pl...tent/2800.html
http://www.elecdesign.com/globals/pl...mages/2801.gif

one detail ist the current protection / current limiter - D3, D4, D5, D6

For better ground - a dual layer PCB

For the BD... Fischer Elektronik heat sink FK243 / FK 245

if you have a evaluation board of a MK III I will test them

 

[Algar]

I've lost the psu that came with the kit. What should I get to replace it. Something not too expensive.

 

[PinkFloyd]

Quote:

Originally Posted by Algar I've lost the psu that came with the kit. What should I get to replace it. Something not too expensive.

One of these is compatible with the stock wallwart (12V type)

 

[Algar]

Quote:

Originally Posted by PinkFloyd One of these is compatible with the stock wallwart (12V type)

You need to have a £500 order to get that outside England. But would just any 12v power adapter be good?

 

[Alick]

Quote:

Originally Posted by Algar You need to have a £500 order to get that outside England.

I suspect you meant outside the UK? They happily ship to Scotland, Wales and N. Ireland with no minimum order quantity, all of which are outside England.
Quote:

But would just any 12v power adapter be good?

But yes, most 12VDC power supplies will work.

 

[FritzS]

What think about LT1364CN8, LT1365CN, LT082, LT084?

 

[PinkFloyd]

Quote:

Originally Posted by FritzS What think about LT1364CN8, LT1365CN, LT082, LT084?

In what context Fritz?

 

[FritzS]

Quote:

Originally Posted by PinkFloyd In what context Fritz?

It's a prinzipiell question - I read about LT082, LT084 in audioXpress (I have a subscription) and about LT1364CN8, LT1365CN in an german DIY forum.

The LT1364CN8, LT1365CN family looks like those OP amps as we use in WNA.

Today I use LM6171, but I have AD8065 and AD843 - but use you asymmetric current source diodes at all - so a little current runs to the output of the OP amp?

PS: I read about "Suntan CD71 105c Non Polar output caps (sounded better than Nitai / Jamicon / Rubycon)" on your homepage - where I can get Suntan Non Polar caps?