There are also products like the
Trends UD-10.1 that allow the PC to "look like a CD transport"
They have some pretty bold claims, as one might expect of a mfg'er...
"On the other hand, Trends UD-10.1 upgrades your PC/Mac to be a hi-end audio source. Thanks to the excellent power supply handling, the high accuracy clock and the sophisticated digital output circuit, the Trends UD-10.1 makes your PC/Mac to behave as a high-end CD transport to work with an external DAC. Yet, the Trends UD-10.1 and PC/Mac combination provides better sound quality, larger storage capacity and a more user-friendly interface than most standard CD players. (Remarks: computer hard disk is far superior to a CD player, no matter the speed, stability, error correction, jitter reduction. They are actually the technology of different eras.) "