I currently have one in for audition with a Pass X350.5 amplifier. I have compared it head to head with a Conrad Johnson GAT tube preamp. The CJ positively smokes the XP30.
The CJ is open and spacious, where the XP30 sounds dynamically and spatially constricted. The CJ has a full round natural tonality and is beautiful to listen to. The XP30 is thin and reedy with no bloom. I am not certain why some reviewers have called this a tube-like sounding pre. To me it sounds like solid state on a diet. Very strange and rather lean. Not bright in the treble, but lean nonetheless. For my money, at $16K, there are a world of choices out there that make more sense. I auditioned the XP-10 with the same amp a while back and actually prefer it to the XP30. Sorry folks. Hate to piss in the punchbowl,but that's my honest opinion and I've listened to a few things in my day.