FX-Audio DAC-X3

I was hoping to use this little DAC with my Pi IIB, but no luck. The indicator lights on the DAC with USB connected to the Pi, but no audio. Anyone else had success with FX Dacs?

FYI, it only plays back 16/44 via usb. Make sure you are not trying to play a 24/44 or 24/48 file. Not sure about pi settings as I gave up Linux long ago.