fwiw, i just did a listening session with a naim power amp and a ps audio 5.0 preamp, which has both an active and passive (straightwire) mode. at the same volume, the active mode had significantly deeper (but less sculpted) bass and more dynamic slam, while the passive had less overall oomph but a lot more high-end detail and, predictably, a lot less coloration. we all preferred the passive, except for vinyl, which sounded a little flat. of course, i'd expect impressions with different gear.
