Steve,Yes a fair bit (unfortunately most of the Time, they just give merely ok factor), and not much really does it for me, The proper stuff doesn't sound like tubes anyway, it sounds good, however it costs a fortune, and now on here save 3 guys could or want to afford it, I Feel The B/P & Manley/ & A/R, oh and a certain class'd' valve amp, else not a chance
Now want would suggest that guys listen to in that Price bracket? B/P But then you've going to need to very effecient speakers, maybe ol Russ Andrews 97Db specials prehaps
Your Soul speacials are £9K a shot + per and those, great amps you listened to last week are what £25K?, They have preform the dance of the seven vails & do topless waitress service for that
Remeber, the best valve amp is no valve amp (or aleast one that doesn't give it self away), they are out there

Wm