I have a Pass Labs XP-32 pre feeding an Air Tight ATM-300R (low power 300b tube amp). All sounds great to me. Best my system has sounded. Detailed, but great natural timbre as well.
For what it’s worth, I also have a Pass Labs XA 25 solid state amp — relatively low power and very well reviewed. The XA 25 sounds great with the XP-32 as well, but the Air Tight is much better (as it should be at a much higher price level than the XA 25). My only point in making the comparison is that a Pass pre with a great tube amp can outperform a Pass pre matched to a good Pass solid state amp.