Why USB to SPDIF and not optical?

I am a little concerned about the statement that it is compatible with native Windows drivers. Do you know how the Link product interacts with XP's audio subsystem? The literature says it accepts 24/96 but I think parts of the XP subsystem probably needs to be bypassed to get 24/96 cleanly through the OS. So does it have drivers that bypass KMixer and the like and will any software product (iTunes for me) work with it directly or do you need special drives (like ASIO) to use it? Any information would be useful.

In addition, XP generally upscales 44.1 files to 48 unless special drives are installed. Does the 24/96 link help with that problem?

FYI, y'all:
My system - PC, Windows XP, ASIO4ALL, JRiver Jukebox > Belkin USB out to Giga Lab Moon USB DAC(NOS). My DAC also has coax and optical ins.

On a whim this afternoon, I inserted a $30 Behringer USB headphone amp (which also converts USB to optical) between the PC and the DAC (optical from the Behringer to the DAC). I was amazed to hear at least a 10% sound improvement, especially on my FLAC downloads from HD Tracks.

Apparently, my DAC prefers optical over USB, but I don't know why.

Mmarvin19 - The JRiver and ASIO configuration is one I am intertested in but have not tried yet. Can you tell if you get 44.1 MHz out of both the Belkin and the Behringer? And do both pass higher frequency without re-sampling? I check this by hooking it up to my HT receiver which reports the input signal sampling frequency. Thanks.

"XP generally upscales 44.1 files to 48 unless special drives are installed."

Not true. My USB converter uses the native drivers and it outputs 44.1 on XP. There are several ways to avoid kmixer, including:

1) unmapping the device
2) Kernel Streaming
3) ASIO

Steve N.
Empirical Audio