Walnut Hi-Fi V2 WAV (& MP3) Player by wt - :ok_hand: screenless budget killer combo DAP/Amp :ok_hand:
Mar 23, 2017 at 3:55 PM Post #2,507 of 3,619
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BTW, I'm having trouble using my Walnut as an amp as the output is very distorted and hollow when doing so. It works perfectly fine as a DAP, anyone got some suggestions on what might be wrong?


Anyone?
 
Mar 23, 2017 at 4:05 PM Post #2,508 of 3,619

DBaldock9

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I haven't been following this whole entire thread - but:
 
1.) Is your Walnut stock?
1.a.) If not, did the same source work, and sound OK before the last mods?
 
2.) Have you checked to verify that the line level signal, which is being fed in to the Walnut, sounds OK with any other Amp?
 
Mar 24, 2017 at 12:38 AM Post #2,509 of 3,619

nick n

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Sounds great so far crazy good on the test nut.
All Soviet except for the opamp, but I have a few different Soviet ones to suit the theme.
The 2 green 100uf do a great job of filtering out some noise from the big 1000uf.
 Had some Silmic 100uf there at first then got some rumbling off the power 1000, and after throwing the 2 green 100uf ones that rumbling started then very quickly settled off to nothing.
 
 
 
This particular test nut by the way is pretty much shot from repeated trials . Garbage can time. Off to order some more spares.
 
Now have to transfer this over to a clean one and start figuring out the  larger case and different button mountings.
 
So basically, ongoing.
But at least the proof of concept is solid.
 

 
^ lighter for heatshrink btw, not for " special audio tweaks "

 

 
Mar 25, 2017 at 2:59 AM Post #2,511 of 3,619
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I haven't been following this whole entire thread - but:

1.) Is your Walnut stock?
1.a.) If not, did the same source work, and sound OK before the last mods?

2.) Have you checked to verify that the line level signal, which is being fed in to the Walnut, sounds OK with any other Amp?


It's not stock, I've rolled op amps in it and have used the Burson V5i most of the time.

Unfortunately I can't remember what sources I've tried with before and after the op amp switch but I'm pretty sure that I've tested the line in somewhere along the line just to see if it worked and that it did, might remember wrong though.

Yes, I've used several different devices with line out and all of them work with other amps.

I've also tried to tighten the 3.5mm line even out connection without it making any difference.

It seems as if my Walnut doesn't like to be used as a amp, too bad as I really like the way it sounds with high impedance headphones and earbuds.....
 
Mar 25, 2017 at 6:05 PM Post #2,513 of 3,619

DBaldock9

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It's not stock, I've rolled op amps in it and have used the Burson V5i most of the time.

Unfortunately I can't remember what sources I've tried with before and after the op amp switch but I'm pretty sure that I've tested the line in somewhere along the line just to see if it worked and that it did, might remember wrong though.

Yes, I've used several different devices with line out and all of them work with other amps.

I've also tried to tighten the 3.5mm line even out connection without it making any difference.

It seems as if my Walnut doesn't like to be used as a amp, too bad as I really like the way it sounds with high impedance headphones and earbuds.....

 
Well, since the amp section is working when fed from the analog output of the Walnut's internal DAC, then the problem must be somewhere between the AUX analog input and the amplifier section.
 
Since the "...output is very distorted and hollow when..." used as an amp, that seems like some part of the circuit is being over-driven, or clipped, due to being pulled too close to one of the voltage rails (bias offset).
 
I'm not familiar with the schematic, but is there a mechanical relay or FET switch being used to select between the internal DAC and the AUX input?
If so, check carefully for any loose or shorted connections, and for any contamination (flux residue) or debris in sockets or between pins.
 
Mar 25, 2017 at 7:54 PM Post #2,514 of 3,619

Dark Helmet

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Looks great :) How did you do it?

Just roughed it up with 330 grit sandpaper and painted it with some white texture paint.  Make sure to do it in a well lit place so it's easier to make sure you get good coverage and it is uniform.  I wanted to paint it red but couldn't find red textured paint at the local hardware store.
 
Mar 25, 2017 at 11:03 PM Post #2,515 of 3,619

waynes world

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  Sounds great so far crazy good on the test nut.
All Soviet except for the opamp, but I have a few different Soviet ones to suit the theme.
The 2 green 100uf do a great job of filtering out some noise from the big 1000uf.
 Had some Silmic 100uf there at first then got some rumbling off the power 1000, and after throwing the 2 green 100uf ones that rumbling started then very quickly settled off to nothing.
 
 
 
This particular test nut by the way is pretty much shot from repeated trials . Garbage can time. Off to order some more spares.
 
Now have to transfer this over to a clean one and start figuring out the  larger case and different button mountings.
 
So basically, ongoing.
But at least the proof of concept is solid.
 

 
^ lighter for heatshrink btw, not for " special audio tweaks "
 
 

 
Holy mother of 'nut!  Wow!!
 
Mar 27, 2017 at 5:13 PM Post #2,518 of 3,619

DBaldock9

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  It seems that after a few hours of playing music on the Nut I get idle noise.  When it's fully charged it's fine, but after a few hours the idle noise starts.

 
Don't idle, keep your foot to the floor... 
wink_face.gif

 
 
Maybe try bypassing the larger filter capacitors with a small value film type capacitor?
 
Mar 27, 2017 at 6:30 PM Post #2,520 of 3,619

DBaldock9

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I haven't actually seen the schematic for the Walnut, but I will be ordering an Amp, soon.
 
If you think it might be power related noise, after running for a while, it's possible that additional filtering on the power rail(s) could help.
 

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