Geoff, he's not talking about playing CDs. The spinning disc he's referring to is the one in the hard drive mechanism. The data being read from the hard drive gets clocked, processed, and reclocked multiple times through all kinds of digital circuitry before it ends up being converted to analog. The jitter that matters is jitter in the timing of digital-to-analog conversion.
Regards,
-- Al
Regards,
-- Al