I have a pair of these http://app.audiogon.com/listings/456096
It's really pity that the seller didn't follow the advice of Jac from jacmusic, who clearly describes about AVVT tubes. They need to be treated with kind of wake up procedure, before you use them after years of storage and that's not possible at home, so, you need to send them to Jac for that. Some tubes even show really poor test results before treatment and become normal after, really strange and exciting that tubes can do that.
Not sure about issue he describes, whatever it have something to do with their long term of not been used, is beyond me and you can better ask Jac about that one, but the price is good, however Jac still have them in stock for EUR500=USD650 a pair plus shipping and even with that price they are worth every penny, imo.
One that I really like to try is EML 300XLS, which, according to some, give AVVT's a bit of the hard time, hmm, thatÂ’s why they got and still have my attention. They don't have that "problem" that for example KR 300XLS have, not perform at their best if used in normal 300B amps. EML's perform identically good in both amplifications, while KR's shining in steroids amps only.
And, there is always EAT, that I strongly believe are simply re-issue of AVVT 300B's. Not sure how they managed that, but I am kind of glad they did.