Your tube amp related Harbeth experience.

My Harbeth SHL5+ can sound a bit on the bright side with SS amplification. I tried them with Luxman 590AXII, and as good as the pairing was it did tend to sound a little bright on some recordings. Moving to a tube amp -- Audio Hungary Qualiton a50i, took care of that issue. This is a sublime pairing and one that I intend to keep until I can upgrade to M40.2/3 in the future.

With M30.1 (haven't tried 30.2s though), I found the opposite to be true. These guys need an SS kick in the gut to really wake them up. Don't get me wrong, they still sound quite good with tubes but you really need big power tube amps. Little guys need not apply here. But they really shine when fed with quality SS amplification. I heard these with Hegel H390 at a dealers last year, and it was a great pairing.

@jjss49 -- I have two system setups in my house. The one in the home office has a glass door plus the usual home office stuff (desk, bookshelves, etc.). However, the SHL5+ are, and always have been, in the media room which has no windows, has a carpet plus rug, and is nicely treated with GIK panels. I spent quite a bit of time and effort in treating that room and placement options, and I can assure you it was not the reason.

If you do a search on audiogon for keywords 'harbeth' and 'bright', you will see a number of folks who have reported similar findings as mine. But keep in mind that it is all relative. What I call bright might be zesty and fun for someone else. Either way, the Qualiton took care of that slight bit of brightness and thinness I experienced with Luxman, but without losing any details or resolution.