I don't change amps much. For many years I had a very nice amp that had great smoothness and musicality. Over this time (about 17 years) I had tried many other amps, including a Krell of the time (which doesn't sound like the Krells of today), Moscode, Bryston, Muse, and some others. Saw no reason to change. With some changes in my system I had to look for a new amp - my old one could not be driven with long ICs. My friend owns an older FetValve and I always thought it sounded very nice. So I was able to find a FetValve EXR5, which in my system was a great step up from my older amp. More transparent, even more musical, and just overall a better sense of pace and invlovement. I upgraded it to an Ultra, and got all that plus much better articulation in the low end and improved extension in the high end. The EXR5 was great but the Ultra was that much better. I have been as happy as a clam with it and was actually not looking to do the upgrade to the current Ultra Double +, but in private discussions with owners who've already done it I was convinced to take the step. I should have it back from AVA in a couple of weeks.
If you were interested in a FetValve then some tube rolling may help optimize the match to the rest of your system. Once done you should find an amp that has excellent natural sound, great extension in both directions, a beautiful midrange and very good space. When well matched with the rest of a system it sounds like real msuic with no mushiness or cloudiness. IMO it punches way above its weight.
I've also heard the OmegaStar series on different speakers and they sounded very nice. A good choice maybe for someone with a tube front end.
