I connected an HRT Music Streamer DAC to my Samsung Galaxy 10.1 tablet now that the Galaxy 10.1 has Ice Cream Sandwich (Android 4.0) and using a "USB Sound Test Tool App" I was able to get sound out of it.
Not sure how to use an outboard DAC without the "USB Sound Test Tool App" - there don't seem to be settings anywhere in Android or any of the audio apps I've (briefly) looked at to "route" sound output to the USB DAC. I'm sure this will all be clarified in the fullness of time....
In other words, I don't see a way to select the USB DAC as the audio output device as default or for a given app or anything. Maybe there is an audio player app that I need to be using?
(By the way, since the HRT Streamer DAC is USB powered, I needed to connect it via a powered USB hub; the tablet will not power it and it will tell you so.)