[shnitz]

Hey everyone, I have an Audio-gd Sparrow.  It's being fed by a coaxial digital signal and is currently driving my Ultrasone Pro 650s.  I noticed with music (and Youtube videos) that the sound will periodically drop down.  It's not a full cut, it's more as if I suddenly turn the volume dial all the way down.  Any idea what's causing this?  If you need me to open up the amp to take pictures or check continuity anywhere, I'll be more than happy to.  I'll be contacting audio-gd as well, and I'll probably open it up to take a look anyway, but I was wondering if anyone would realize off the top of their head what was going on.
 
BTW, I get some wicked channel imbalance at low settings.  I usually turn my source pretty far down, so that I am not using the bottom 20% of the volume pot.