I heard it when I auditioned the pass aleph/volksamp 30 amps. We had a wadia 830 driving it. First we played it with the preamp then with the wadia driving direct. The preamp added quite a bit of cloudiness to the recording. The salesman remarked that most people just buy the all-tube gain stage audio research ls-16. I don't notice nearly this much degredation when I move my adcome 750 (in passive or active mode) in and out of my home system. My sony xa7 cd player can drive an amp directly.
