[Pasion]

Hello - I'm looking for a side project to work on in my free time and thought I could use a DIY usb DAC/AMP. I wonder about using a Raspberry pi embedded system as a "software defined dac/amp" if this is feasible. I would greatly appreciate some advice such as the feasibility of such a project or where to go/books to read to learn more.

 

[cyteen]

Most usb dacs out there are USB audio 1.0 which the raspberry pi has problems with.  As well as being USB audio 2.0 this audio widget is async and the designs are open source (if you want to do your own layouts) or you can buy working example from a couple of sources.

http://www.diyaudio.com/forums/digital-source/185761-open-source-usb-interface-audio-widget.html
 
http://www.diyaudio.com/forums/digital-source/201364-raspberry-pi-new-diyers-digital-hub-13.html#post3330182
 
http://www.qnktc.com/usb.php
http://www.yoyodyneconsulting.ca/pages/Audio_Hardware.html

 

[KimLaroux]

Semantics... you cannot have a "software defined DAC/Amp", because software is digital and DACs and amplifiers are analog.
 
Anyways. As cyteen said, the Raspi has trouble with USB audio. It's unreliable and introduces glitches in the audio signal.
 
Which is not really surprising, because the Raspi is essentially a hack. It's not compliant to computing standards. If you want... 
 
Wait, I'm not even sure to understand what you're trying to do here. Using the Raspi as a slave USB device that accepts digital audio signal and transform it to analog audio? I doubt this is feasible... or even reasonable considering there exist really great DIY USB DAC for the price the Raspi goes for.

 

[cyteen]

http://www.raspyfi.com/raspberry-pi-usb-audio-fix/
 

 

[jcx]

the pi isn't true open source - can't see everything
 
other small boards may be better on features - look at the BeagleBone Black http://makezine.com/magazine/how-to-choose-the-right-platform-raspberry-pi-or-beaglebone-black/

 

[mcluxun]

actually you dont have to output through usb. rpi is loaded with i2s output ability.