usb audio. spdif only mono

hi!
i have a maya 44 usb.

i connected it via spdif to my receiver. the signal seems to be only mono where as if i take a headphone its stereo.

also, it sometimes crackles a bit.

are there different drivers vor standard usb audio and which kext is it?

thanks
cheers

This might not help you nemster but I have this device:

COMODOW USB 5.1 Audio

It's 100% recognized and functioning in OSX 10.4.8 AMD/INTEL/SSE2/SSE3 by JaS.

You can get 1 from eBay for $10.00 USD shipped.