I share your views on passive preamps. But the Res Audio players do not have a passive preamp in them. They have an active line stage that that follows the volume control and that, on paper, looks as good as any decent silly state preamp, with oodles of drive and low output impedence. Maybe it is not as good as claimed - don't know. But I find that the problem manifests itself, even with a preamp in place, if I run the Res Audios at lower than full volume. Again, I doubt you can point your finger at the quality of the volume control, but it appears more likely to be the problem than the output stage. I think I recall hearing that the volume control is the same as that used by Rowland. My theory is that when implemented in a CD player that it attracts more RF problems the more resistance is introduced into the signal path. I have that theory for no other reasons than that; one-box CD players are tricky beasts to keep digital nasties out of the analogue (which is why DVD players sound bad IMO - much more digital rubbish sprayed around inside the box); the effect on the sound increases as volume is attenuated; and, the effect sounds awfully like RF problems I have experienced at other times and in other systems.
