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Reference DAC Module - Discrete R-2R Sign Magnitude 24 bit 384 KHz

Last week I finished replacing the 4 onboard regulators 3.3v, 5v, -5v and 1.2v with muzgdiy regulators.
I glued some alumina ceramic pads on the back for better heat transfer, on the 1.2v I added an additional heatsink.

Result of this: better 3D soundstage, deeper, better separation between instruments/voices, more relaxed, ... all good ;)

On the last picture you see the surgery table and my hdmi microscope that makes this minuscule soldering possible :)

Nice. Wish Soren made dam1021 even easier for power modding. Audio is never better than the power it is created from. It seems that good powering (low impedance, wide bandwidth, low noise) is foundation to all audio foundation foundations :) This apply to both digital and analog domains. My experience is that good PSUs can elevate already great circuits like dam1021 to completely new level of sound quality.
 
Nice. Wish Soren made dam1021 even easier for power modding.
Yes, like adding some vias that matches 3pin regulators
The Polish Muzgdiy regulators are playing fine :)

Hi Søren,
I ordered two dam1021-12 rev4 boards yesterday. Would it be possible that you provide a short description of the actual version of your vref "factory mod"? What is useful, what isn't, regarding caps, resistors, etc.
You can still add some capacitors to the vref, Søren has supplied some nice vias for that.
Extra capacitors brings the noise floor lower.
 
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Issue with Soekris DAM1021 v2

I need help with my Soekris DAM1021 v2.
Today when I turned it on, after a couple of seconds there was a big thump so I turned it off immediately.
I started measuring continuity and voltages and noticed that POWER IN +12VDC wire (upper connection in J1) disconnected.
Fixed it and powered on again. The power led lighted and I2S input locked but no audio. Then I measured J2 and some values are weird:
PWR A-: 0.82V
PWR A+: 3.45V
Instead of -5V, I read 0.22V
5V, 3.3V and 1.2V were OK.
It seems to me that at least the diode bridge failed. Is it the part identified as D2? What's its part #?
Any other idea on what could be damaged?
Thanks.

Adolfo
 
Fundamental truth... All audio is power.

"....Audio is never better than the power it is created from. It seems that good powering (low impedance, wide bandwidth, low noise) is foundation to all audio....."

Superb TioFrancotirador... This is the best quote I have ever read in the DIY site!
Power supply is the key....Shame the vast majority of audio engineers fail to understand this.

All the best
Derek.
 
I have another "randomly loses sync" issue. Setup: two dam1021 boards in balanced dual mono config; input is I2S via Raspberry Pi; using Normunds' input+switch board to connect the two boards plus Rpi. DAM boards are powered by DIYINHK LT3042 power supplies at +/- 12V.

Most of the time everything just works as expected. Randomly, though, the dam1021 boards will lose sync. When this happens, it is most likely to occur right when a new song starts. This is how it usually goes over:
  • New song starts, plays normally very briefly, maybe one or two seconds
  • Both DAM boards lose sync (on-board LED starts flashing), brief silence for one or two seconds
  • One board (i.e. one channel) regains sync, starts playing; other board/channel is still silent, again one or two seconds
  • The channels swap, so the previously silent one starts playing, and the other goes silent. Another 1-2 secs.
  • The other channel recovers and both resume playing normally.

I spent several hours listening, and this happened so little (maybe not at all?) that I thought I could live with it. But then I put a new album in the playlist. And it started consistently doing it at the start of every single song.

I thought it might have something to do with the files, but my entire collection is all FLAC-encoded CD rips (i.e. 16/44 redbook audio).

So then I thought it might have something to do with the RPi and/or software running on that. I shut down the system for a few days, came back last night. Turned it on, started playing the same album. No issues. So clearly it's not specific to those particular song files.

Any thoughts on where I might want to look given the description of the problem?

Did you sort this? I had the same problem when I moved the Dam from a wooden box to a metal enclosure. It turned out to be the metal screws creating a ground loop of some sort as the pads around the screw holes are part of the ground plan on the dam. I used nylon screws and it sorted out the problem straightaway.
 
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Did you sort this? I had the same problem when I moved the Dam from a wooden box to a metal enclosure. It turned out to be the metal screws creating a ground loop of some sort as the pads around the screw holes are part of the ground plan on the dam. I used nylon screws and it sorted out the problem straightaway.

I'm still facing the problem, although I haven't had the time to mess with it much since I posted. It's definitely random. I've let this system play non-stop since I posted, but it's the exact same three-album playlist on repeat. When I have a few minutes I pop my head in and listen, I don't hear the issue. I'm not logging serial output from the dam1021s, so I can't say for sure if it's really never doing it or not. But at least my (infrequent) random, quick-checks suggest it's not doing it often; I can at a minimum confidently say it's at least not doing it as bad as it was when I posted about the issue, as that would happen at the start of every song.

What I need to, though I haven't had time, is to create a new playlist. That seems to be what triggered it last time. That is, it was fine (or at least mostly fine) for quite a while, and just after creating a new playlist, it started exhibiting the problem. If true, that to me suggests a software problem (OS and/or MPD). So I'm also waiting on my OS distribution (Archphile) to release the latest version of MPD. (I could of course try other distros and/or self-compiling, but I haven't had the time.)

My dam1021 + Normunds board + Rpi assembly is connected to the chassis entirely by nylon standoffs. In fact the Normunds board PSU and dam1021 PSU are also using nylon standoffs.
 
my intall kits for dam1021

My intall kits for dam1021:D The work has been done!AES,Coaxial,usb, iis(hdmi),remote,oled display.
 

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