You don't know what you're missing until it's there.
While I'm not sure the XP-30 is the most (M)usical preamp I have heard, Peter's system, with the XP-30 added, offers a presentation so sure and engaging that I am still hearing and 'feeling' the music of last night's listening session.
Characteristics are rich and solid vocals, stunning speed, a newfound soundstage breadth, a substantially greater transmission of complex symphonic passages, more persuasive imaging and this listener's life-list level of timbral accuracy.
The complementarity of the XP-30 with Peter's other system components is disarming: even with flawed recordings the music can somehow survive. That's a feat.
the other listener in Peter Ayer's thread (two entries above)