I had issues going into the Gungnir's USB input with an old Power-PC Mac Mini running Tiger, but one of these did the trick:
Actually this one did not work but an older one that looks identical except it is blue did. The Gungnir doesn't seem to like older USB (1.1?) audio standards.
Anyways my point is to try a converter, you don't have to spend much and the Gungnir's coax inputs are better anyways.
Edited by grokit - 5/30/13 at 11:29pm