charleski
Major Contributor
In the latest Stereophile they review the Cyrus CDI-XR, a $3k CD player. One quote from Cyrus' head of research stood out, "If the data is not correctly read the first time, the CD head needs to skip back on the spiral to re-read it. This moving causes noise withing the power supplies, etc, which degrades the overall performance." Now, on the face of it, this isn't entirely nonsense, after all we're dealing with stepper motors being fed by a PWM chopper drive. If the ground plane for the motors isn't properly isolated from the analog electronics it is conceivable that noise would leak through (though this would be evidence of poor design). But this would clearly be measurable, and I wonder if anyone's seen measurements of a CD player that exhibit this sort of breakthrough noise on the analog ground plane. It is possible that this would differ depending on the CD, with more noise visible on discs that aren't tracking well and producing more head shuffle. I know that at least one CD test disc contains tracks specifically designed to elicit tracking errors.