USB DAC Sound Card on Debian

On Debian by default when you plugin a USB DAC (Soundcard), it does not become the default audio playback device which is not particularly useful. 

To change the default soundcard or more correctly the playback hardware device, you need to edit the ALSA config file eith in the user home directory ~/.asoundrc or globally in /etc/asound.conf.

First find out the names of the soundcards available on your system with the aplay command. 

[~] # aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Generic [HD-Audio Generic], device 0: ALC887-VD Analog [ALC887-VD Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Generic [HD-Audio Generic], device 1: ALC887-VD Digital [ALC887-VD Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: M2496 [M Audio Audiophile 24/96], device 0: ICE1712 multi [ICE1712 multi]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 2: HDMI [HDA ATI HDMI], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 3: DAC [USB Audio DAC], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

I want to use my USB Audio DAC, which has the name "DAC".

This is my ~/.asoundrc

pcm.!default {
    type hw
    card DAC
}

ctl.!default {
    type hw
    card DAC
}

To test the sound is now coming out the correct device you again use aplay. 

[~] $ aplay /usr/share/sounds/alsa/Noise.wav
Playing WAVE '/usr/share/sounds/alsa/Noise.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Mono