I have two systems and use Martin-Logans in each (but also have a pair of Thiels that see occasional service). Both the Logans and the Thiels are so revealing of midrange textures that solid state amps just sound either mechanical or plain irritating. I have tried the Krell but not the Pass. However, my vote is to look at a tube design. There is a lot of techno-babble about impedence issues, which I am sure is relevant, but if you try it and it works then the techno-babble doesn't matter. The tube amps I use are more lively on the Logans or Thiels than any solid state amp I have tried - figure that out. But importantly, the mids now sound like real voices and instruments. I used to avoid tubes because of the hassle factor, so do not believe I have a bias. But in my solid state days, I was always struck by the beauty of midrange sounds at live events that just did not seem to exist on my recordings. When I first put a good tube amp in place I realised what the problem had been. $9,000 is plenty. I agree with the earlier posts re VAC and VTL. I think you will be pleasantly surprised.
