Ok - some information I've gathered, thought I would share:
I wondered why USB DACs showed such poor audio quality when the USB portions of the DAC were used. Afterall, the CD ROM connected via USB doesn't matter.
If the connection method doesn't matter for a CD-ROM, then why is it that audio over USB on a USB DAC is so bad due to jitter? What makes one ok and the other not ok?
Quote: Originally Posted by AlexO
The CD rom sends a data stream over the IDE or SATA or SCSI connection. The problem arises when sending a PCM stream to an external Digital to Analog converter. PCM protocol lacks clocking and this is what jitter is: imprecise clocking. It seems that some interfaces deal better with this issue than others.