A custom Nexus 7 interworks with a standard USB DAC FiiO E10 (that doesn’t work with stock Samsung Galaxy S III for the time being):
custom Nexus 7 > digital audio stream >> USB DAC/amp FiiO E10 >> Sennheiser HD-380
Instructions for customizing a Nexus 7:
http://forum.xda-developers.com/showthread.php?p=29805237&highlight=asound#post29805237http://forums.slimdevices.com/showthread.php?82110-Instructions-for-connecting-USB-DAC-to-Touch&highlight=Udev"Code:
pcm.usbdac {
type hw;
card Audio;
}
ctl.usbdac {
type hw;
card Audio;
}
pcm.!default usbdac
Back up your asound.conf and add this (or for simplicity sake, replace it with this)
This allows me to use my Nexus 7 to play over my Fiio E10 USB DAC, N7 + E10 + HD380 == fun.
It's too late for me to work on combining this with the stock asound.conf.
It's in /etc/ on stock rom and works once replaced."
http://forum.xda-developers.com/showpost.php?p=29830741&postcount=472"We are lucky, no such file or luck on GN or SGS3 yet, need to first understand how alsa works on those phones.
Yes, double check you need the alteration.
I never got sounds out the USB DAC without it.
And now with it, plays fine with DAC, but also when DAC is not plugged, plays sounds as if I never changed anything.
Which is nice either way, not needing to change the file all the time.
Need to find out if/how I can modify the default device for np and sgs3 now, they neither had nor sorry the file.
No support meaning adding the file doesn't change anything there."
http://forum.xda-developers.com/showpost.php?p=29857696&postcount=497