PB,
As you've already witnessed, you're going to encounter some resistance around here when the subject of tube amplification is brought up. Actually the whole subject of amplification affects on sound quality is a bit touchy. One of the core tenants of Axiom speakers is their engineered neutrality and balance. When you slap a tube amp on them (and invariably comment that it 'warms' up the sound), some view it as "messing with perfection".
Personally, I think you should have fun and do what you want with the speakers. Tinkering and experimentation is part of the fun of this hobby, and it need not be approached with the clinical hues of "right" vs. "wrong" that some seem to favor.
I've never heard Axiom speakers when powered by a tube amp. However, my office set up consists of Sennheiser HD650's and a Little Dot MKII tubed headphone amp. I love the setup. Almost as much as my home Axiom system. I chose the LDmkII amp over several IC-based amps, as I listen to a lot of classical and jazz and the tubes impart a delicious warmth and intimacy to the sound. I have often thought of taking the LDmkII home and using it's pre-out functionality with my M80's to see what it sounds like, but I've never done it. Perhaps I should.
