USB sound card doesn't quite work

[dubya]

I ordered a cheap Syba USB stereo sound card to go with my PogoPlug E02G, but it doesn't quite work. ALSA seems to recognize it, i.e. alsamixer works and shows all channels unmuted, and mpd will make the 'receiving data' light blink steadily, but no sound comes out. However, if I unplug the device and plug it back in right away, everything is fine, except that mpd is eating all possible CPU. Rebooting returns the card to the not-working state.

I tried "alsactl store" when it's working and then "alsactl restore" when it's not, but it hasn't fixed the problem. Does anyone have a suggested fix? Is there a way to read and dump all of the sound card's registers?

lsusb shows this:
Bus 001 Device 004: ID 040d:3400 VIA Technologies, Inc.