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

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S

soekris

Member
Joined 2009
soekris.dk
Paid Member
vodomore said:
Hi Soekris,



I have dam1021 rev1, and I'm trying to do the 16 caps mod.
Soekris DAC: Modding VRef | H i F i D U I N O

I found those holes in the PCB are very tiny, and around half of those holes were covered by PCB paint I guess and can't even put a single copper thread through it.

So, my question is, seems those holes are not connected to other parts, right? Can I expand those holes using a tiny drill bit?

Thanks!
Click to expand...

Those via holes are connected to the inner power layers, if you drill them you will ruin the board.
 
D

derekr

Member
Joined 2009
Slazi said:
Is there any player for Raspberry pi that can control dam1021's volume directly from their UI? I've tried moode, rune and volumio but can't get them work.
Click to expand...

Another option is to leave the RPI to do its thing and use a microcontroller to do just about anything you want to do on your front end. With the DAM’s built in command set, the addition of an IR receiver and/or a rotary encoder and an OLED display all your DAM needs can be met....:)

Powerful things, uC’s..... start with an Atmega 328P-based 5V/16MHz Arduino - LOTS of support online. Including an OLED display, IR receiver and a suitable uC your total outlay will be well below $20 - which I’m sure you’ve more than exceeded donating to Tim, Michelangelo etc. Lurking out there is quite a bit of free code that can be adapted to those DAM needs - try DimDim’s site and HIFIDUINO for starters.
 
S

Slazi

Member
Joined 2013
derekr said:
Another option is to leave the RPI to do its thing and use a microcontroller to do just about anything you want to do on your front end. With the DAM’s built in command set, the addition of an IR receiver and/or a rotary encoder and an OLED display all your DAM needs can be met....:)

Powerful things, uC’s..... start with an Atmega 328P-based 5V/16MHz Arduino - LOTS of support online. Including an OLED display, IR receiver and a suitable uC your total outlay will be well below $20 - which I’m sure you’ve more than exceeded donating to Tim, Michelangelo etc. Lurking out there is quite a bit of free code that can be adapted to those DAM needs - try DimDim’s site and HIFIDUINO for starters.
Click to expand...

I already have all parts for ardam but I thought it would be cool to control volume by phone. Then I don't have to put too much eletronics so the unit would be more simple. Less noise and less power supplies.

I don't know why but with volumio and runeaudio dac didn't lock signal. With moode it worked at first but it was really unstable. With different sd card it was stable but there was no sound. And now it's corrupted because I took power cable off :D
 
M

matt_garman

Member
Joined 2008
Paid Member
Slazi said:
Is there any player for Raspberry pi that can control dam1021's volume directly from their UI? I've tried moode, rune and volumio but can't get them work.
Click to expand...

I don't believe any RPi distro can do what you want out of the box, but if you're willing to "open the hood" and do a bit of extra config work, it is possible. The gist is that you use the dummy ALSA device as your mixer for MPD. The you use ALSA's API to listen for volume change events, and when you receive one, send a serial command to the Soekris DAC to change volume accordingly.

I have written fairly detailed instructions on my website. See the very bottom of that page for an mpd.conf that might fix your failure-to-lock issue (specifically, the format "*:32:*" option, as that forces all output to be 32bit, which the dam1021 needs to lock on a signal).

Hope that helps!
 
S

Slazi

Member
Joined 2013
matt_garman said:
I have written fairly detailed instructions on my website. See the very bottom of that page for an mpd.conf that might fix your failure-to-lock issue (specifically, the format "*:32:*" option, as that forces all output to be 32bit, which the dam1021 needs to lock on a signal).

Hope that helps!
Click to expand...

I tried to change volumio's mpd.conf settings through ssh but it didn't help. Dac doesn't lock signal and I haven't got any sound from volumio nor picoreplayer. I had sound (moode and airplay) 15minutes two days ago but then it corrupted and after that this has been driving me crazy. Is this broken?
 
D

Dimdim

Member
Joined 2008
Slazi said:
I tried to change volumio's mpd.conf settings through ssh but it didn't help. Dac doesn't lock signal and I haven't got any sound from volumio nor picoreplayer. I had sound (moode and airplay) 15minutes two days ago but then it corrupted and after that this has been driving me crazy. Is this broken?
Click to expand...

Go to Volumio's settings and enable resampling to 32bit.

Editing mpd.conf won't help since Volumio on reboot will overwrite it with its own version.
 
M

maikel76

Member
Joined 2013
Dimdim said:
Looking at J3, the pins you need are ISO RXD IN and ISO TXD OUT. You will also need a ISO GND connection.

Keep in mind that this serial port is isolated from the DAM but shares a common ground with your USB to I2S interface..

Plus, these pins are at 3.3V levels (and not RS-232 levels), assuming that the dirty side of the isolators is powered by 3.3V. So your RS-232 interface will not work. You will need a "simpler" interface, like this one: USB 2 0 to TTL UART Module Serial Converter CP2102 STC Replace Module Dteg | eBay which you should jumper for 3.3V operation.
Click to expand...

Hi Dimdim,
I'm doing some preparations before connecting the dam1021.
I suspect I can connect these isolated serial pins (that you mention above) directly to my raspberry pi's GPIO-port pins. In my understanding the pi uses 3,3V as logic level. Is my assumption correct?

I'm not using USB but want to feed I2S from the pi to the isolated input on the dam, that should be ok if I use the 3,3V and gnd from the pi isn't it?

Thanks a lot again, can't wait to start connecting but I'll have to be a little bit patient.
 
TNT

TNT

Member
Joined 2003
Paid Member
fred sonnen said:
yes, these.
thank you

The remaining cable lengths from and to the DAM shouldn't matter, should it?
Click to expand...

I'll think many would agree to that keeping cables short is not an all bad idea. But there are exceptions. Cable carrying digital coded information, with no bit errors, can be said to be perfect information conveyors. All other do have losses.

On the other hand, keeping cables short means that units in the system come closer to each other :) and thus interfering by e.g. EMI radition - this might be a bigger problem than cable length - here some well thought out system architecture can mean a difference.

But don't go banas on it :)

//
 
D

Dimdim

Member
Joined 2008
maikel76 said:
Hi Dimdim,
I'm doing some preparations before connecting the dam1021.
I suspect I can connect these isolated serial pins (that you mention above) directly to my raspberry pi's GPIO-port pins. In my understanding the pi uses 3,3V as logic level. Is my assumption correct?

I'm not using USB but want to feed I2S from the pi to the isolated input on the dam, that should be ok if I use the 3,3V and gnd from the pi isn't it?

Thanks a lot again, can't wait to start connecting but I'll have to be a little bit patient.
Click to expand...

All of your assumptions are correct. :)
 
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