Wanting to use the raspberry as stereo I bought on amazon a key Kingston - DataTraveler SE9 - USB flash drive - 64 GB - Silver to store mp3. I use Raspbian like bone with mopidy as a music server. One problem rapsberry the sound card is catastrophic. Seeing the previous comment, I bought this article. Bilan nothing to do, sound quality nickel bass power ... My speaker + subwoofer kit purrs again;)
For the consideration of the Usb dac: In a console
sudo nano /etc/modprobe.d/alsa-base.conf // Change the following line value to 0 or -2: snd-usb-audio index = 0 options
Basically for a hundred euros (+ rapsberry dac usb + usb key 64 go), hi-fi system on top Thank you !!!!!!