I've been using a USB DAC (nuForce Icon uDAC-2) with my OSX machines for ~18 months, and with my retina Macbook Pro running OSX 10.8 since August. In the last few weeks it's started to have problems. The audio will drop out about 40 seconds into use, and it doesn't come back until I disconnect and reconnect the DAC from the USB port.
I initially assumed this was the uDAC crapping out, since it's not the best in the world, and bought a fiio e17 to replace it. However, the fiio e17 is having the exact same problem.
I've now reproduced the problem with two different DACs using multiple USB cables, multiple hubs, and connected directly to my laptop via each of its two USB ports. The problem persists, leading me to believe it's not a problem with the cables, the DACs, or my USB hubs.
Googling produces references to some kind of USB audio problem in Mountain Lion, but no solutions to the problem. The general solutions to dropout on a USB DAC seem to be "turn off wireless" and "disconnect all other USB devices", but those aren't really viable options for me -- wireless is this laptop's only connection to the internet, and my other USB devices are my keyboard, mouse, and external HD. They're not really optional.
Is anyone familiar with this issue? Are there any solutions I should try?