For those who may be interested in a High performance USB to S/PDIF conversion the
New NuFORCE U192S might be a good consideration.
FeaturesUSB 2.0 audio to S/PDIF converter
Coaxial S/PDIF output
Optical TOSLINK output
16 or 24 bit resolution
44.1, 48, 96, 176.4, and 192 kHz sampling rates supported
USB-powered, no external power supply required
