After comparing my connection of USB from HTPC and CD Player digital output, I was surprised to find the difference - CD digital sounds better than the USB from HTPC. In my mind, there shouldn't be.

The following are my connection:

On HTPC, I play iTune on files Apple Lossless, USB out, to USB in on the A/V Receiver H/K 745.

From CD changer, coaxial cable to coaxial input on the A/V Receiver H/K 745.

In my mind at the input level to the Receiver: usb and coaxial are all digital.

Anyone can help decipher this issue? Propose any settings on my HTPC, which uses XP pro.