Walnut Hacking V2 Official Thread
Jan 2, 2017 at 5:50 AM Thread Starter Post #1 of 12

vapman

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THIS PAGE IS TO SEPARATE WALNUT MODDING TALK FROM PLAIN WALNUT TALK.
 ​
There is more techical talk than player talk in the main thread 
and wanted to give the non-techies a place to discuss their player
as well as the nerds a place to nerd out.
 ​
As always, before posting, read the FAQ!
Page 1/2 | Page 2/2
Yours sincerely,
vapman
 
Jan 2, 2017 at 5:50 AM Post #2 of 12
2
 
Reserved for crucial information for those interested in modding their Walnut
 
  well I see some huge blocks reserved above so I'll start off for now with brief overview of things soon to manifest for mine.
All parts ordered and waiting to show up, only a few to grab locally.
Everything is in tentative plans only stage so far until it all shows up and actually works/fits in the finished builds, ironed out and trouble free.
 
Volume potentiometer replacement:
 
Member T.R.A.N.C.E. pointed out my mistake in thinking they were 100K for some reason.
These are 10k values stock.
 
  
  1. Audio Note 100k ohm model 81914.
I thought I'd try one to see how it reacted. These are hand built.
  1. ALPS-68580 Blue Velvet 10k ohm
  2. Will use some stock to be able to keep the on/off function intact for trial builds.
 
^ the Audio Note and the ALPS do not have the built in switching ( ON/OFF ) sections, and only control the channel volumes.
There should be two points on the circuit traces where those ON/OFF stock volume pot legs would gets soldered into, but will be empty when replacing with the others.
 I will use connection wiring soldered to those two trace points and route them to a front mounted mini slider switch or micro metal toggle.
This will require always checking to see the volume is turned right down each time I turn it on.
 
New Housing:
 
 NOS Soviet themed mod ( this better sound decent or...) = those Soviet New Old Stock capacitors are larger than stock for the same values needed. This requires a new housing for added routing and fitting, as well as any other bulky idea I might use. Perhaps an bigger battery mAh for a further extended time between charging.
Only reasonable case is this one:
http://www.ebay.com/itm/162173794681?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
=74mm by 29mm by 80mm
 
It keeps the PCB front to rear distance the same ( 80mm ) so the inputs/outputs require no extending and are easy to make holes for in whatever faceplates used,
but adds ~9mm extra height and ~24mm width.
 
 
Capacitor Fun:
For dedicated themed units
 
* the small 10uf apparently have tiny legs so will have to see how a larger set fits.
 
New Old Stock Soviet caps:
 Most electronics back then were manufactured in Military factories, obviously the best went to that, and rest were likely sorted accordingly after.
No real way to tell.
No idea how well they have held up for tolerances by now so some values may be tried in a larger value or some other models may be sourced.
 
Have some mil-spec silver plated copper wire in case  things need serious rerouting
All aluminum oxide electrolytics
 
1000uf  K50-29  axial ( 16v )
200uf    K50-16  ( 25v )
100uf    K50-29V axial ( 25v )
10uf      K50-29  axial ( 16v )
47uf      K50-35  ( 63v )
 
 
For the following  they will use other brand power filter caps to hopefully fit, anything above 10mm wide seems to cause case-fit problems in it's position and most 1000uf audio caps are above that.
Another member might chime in on audio vs low esr ones...
 
Elna Silmic II:
 
10uf  ( 25v )   = 5mm x 11mm
47uf  ( 10v )   = 5mm x 11mm
100uf  ( 16v ) = 10mm x 12.5mm
 
Elna Cerafine:
 
10uf ( 25v )  = 5mm x 11mm
47uf  ( 10v ) = 6.3mm x 11mm
100uf ( 10v ) = 8mm x 11.5mm
 
Nichicon:
 
10uf SW   ( 16v ) = 4mm x 7mm
47uf KZ   ( 10v)   = 10mm x 12.5mm
100uf KA  ( 16v ) = 5mm x 11mm
 
 
Various 1000uf which may or may not fit
 
Roederstein 16V EKS LL  = 10mm x 20mm
Vishay 135  16v = 10mm x 30mm :)
Nippon /UCC 25v = 10mm x 20mm
Panasonic FC 16v = 10mm x 25mm
 
Others which may or may not fit
 
Frako 47uf axial 25v ( german )  = 6mm x 13mm
 
 
 
to be continued...
 
 
Jan 2, 2017 at 7:24 AM Post #7 of 12
well I see some huge blocks reserved above so I'll start off for now with brief overview of things soon to manifest for mine.
All parts ordered and waiting to show up, only a few to grab locally.
Everything is in tentative plans only stage so far until it all shows up and actually works/fits in the finished builds, ironed out and trouble free.
 
Volume potentiometer replacement:
 
Member T.R.A.N.C.E. pointed out my mistake in thinking they were 100K for some reason.
These are 10k values stock.
 
  
  1. Audio Note 100k ohm model 81914.
I thought I'd try one to see how it reacted. These are hand built.
  1. ALPS-68580 Blue Velvet 10k ohm
  2. Will use some stock to be able to keep the on/off function intact for trial builds.
 
^ the Audio Note and the ALPS do not have the built in switching ( ON/OFF ) sections, and only control the channel volumes.
There should be two points on the circuit traces where those ON/OFF stock volume pot legs would gets soldered into, but will be empty when replacing with the others.
 I will use connection wiring soldered to those two trace points and route them to a front mounted mini slider switch or micro metal toggle.
This will require always checking to see the volume is turned right down each time I turn it on.
 
New Housing:
 
 NOS Soviet themed mod ( this better sound decent or...) = those Soviet New Old Stock capacitors are larger than stock for the same values needed. This requires a new housing for added routing and fitting, as well as any other bulky idea I might use. Perhaps an bigger battery mAh for a further extended time between charging.
Only reasonable case is this one:
http://www.ebay.com/itm/162173794681?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
=74mm by 29mm by 80mm
 
It keeps the PCB front to rear distance the same ( 80mm ) so the inputs/outputs require no extending and are easy to make holes for in whatever faceplates used,
but adds ~9mm extra height and ~24mm width.
 
 
Capacitor Fun:
For dedicated themed units
 
* the small 10uf apparently have tiny legs so will have to see how a larger set fits.
 
New Old Stock Soviet caps:
 Most electronics back then were manufactured in Military factories, obviously the best went to that, and rest were likely sorted accordingly after.
No real way to tell.
No idea how well they have held up for tolerances by now so some values may be tried in a larger value or some other models may be sourced.
 
Have some mil-spec silver plated copper wire in case  things need serious rerouting
All aluminum oxide electrolytics
 
1000uf  K50-29  axial ( 16v )
200uf    K50-16  ( 25v )
100uf    K50-29V axial ( 25v )
10uf      K50-29  axial ( 16v )
47uf      K50-35  ( 63v )
 
 
For the following  they will use other brand power filter caps to hopefully fit, anything above 10mm wide seems to cause case-fit problems in it's position and most 1000uf audio caps are above that.
Another member might chime in on audio vs low esr ones...
 
Elna Silmic II:
 
10uf  ( 25v )   = 5mm x 11mm
47uf  ( 10v )   = 5mm x 11mm
100uf  ( 16v ) = 10mm x 12.5mm
 
Elna Cerafine:
 
10uf ( 25v )  = 5mm x 11mm
47uf  ( 10v ) = 6.3mm x 11mm
100uf ( 10v ) = 8mm x 11.5mm
 
Nichicon:
 
10uf SW   ( 16v ) = 4mm x 7mm
47uf KZ   ( 10v)   = 10mm x 12.5mm
100uf KA  ( 16v ) = 5mm x 11mm
 
 
Various 1000uf which may or may not fit
 
Roederstein 16V EKS LL  = 10mm x 20mm
Vishay 135  16v = 10mm x 30mm :)
Nippon /UCC 25v = 10mm x 20mm
Panasonic FC 16v = 10mm x 25mm
 
Others which may or may not fit
 
Frako 47uf axial 25v ( german )  = 6mm x 13mm
 
 
 
to be continued...
 
Jan 2, 2017 at 8:15 AM Post #8 of 12
Nice to see everyone! :wink:

So I have been researching (not done) but what is the possibility of lowering the output impedance of the PO? I was going to crack the nut again and take some snaps and continue researching.

I like this device and it's inspired me to break out my college electronic design books!
 
Jan 2, 2017 at 8:51 AM Post #9 of 12
There are also Bourne Pro Audio pots and I believe some have "switch" capabilities. Again, still researching!
http://www.bourns.com/products/proaudio/products
 
Jan 3, 2017 at 5:32 PM Post #10 of 12
I was thinking about adding a digital output to the desktop Walnut I make in the future. I am wondering if I can take a digital signal straight from the SOC or if more would need to be added. At the least, I'm going to use RCA/XLR outputs on it
 
Feb 10, 2017 at 7:28 AM Post #11 of 12
I'm looking to do some moding in my local hackerspace but total noob on this
rolleyes.gif
 interested in a trying out new opamp but also new potentiometer (alps?). How do you guys made the switch for on/off function? what op amp do you suggest? some people seems to agree on JRC NE5532 in the other thread. 
 
Sep 9, 2017 at 1:15 PM Post #12 of 12
Could be offtop but still...
Where can I download the firmawares for V2? Is it worth trying?
 

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