In the April Issue, a followup review of the Grace Design m902, John Atkinson states that he has found USB interface on many DACs to contain greater amount of jitter than the sPDIF interfaces.
Could someone explain to me why this is the case? My understanding is that the USB interface protocol contains error correction and clocking mechanism just like the old serial interface did, whereas the sPDIF does not. So, theoretically, there should be NO jitter at all when going through the USB. What am I missing here?