USB connection to MusicalFidelity M6SDAC does not play

I have difficults with my raspberry and the usb. I connect a MusicalFidelity M6SDAC to USB. It is detected, but when I play music, the M6SDAC shows the right sample rate of the current song, but nothing is to hear.
I use musicbox_v0.7.0RC6. When I play music with my Linux-PC the behaviour is the same. When I play music with my Windows-PC the music plays (after installing a special usb driver). MusicalFidelity means that the M6SDAC should be detected with Linux kernel 2.6.33 or later. Can you please help me.

If it doesn’t work under your Linux pc it’s not going to work in pimusicbox. It’ll be a lot simple to debug/get working on your Linux pc so I’d suggest starting there.