I just discovered my latest Mikhail "gotcha". At his last public appearance, the June 2008 NorCal meet, I bought a NOS 6385 tube from Mikhail for what turned out to be about 50% more than the going price at the time. Later I wrote that off as more bad dealings with Mikhail. Today, I stuck it on the Jackson 648A tube tester I recently bought. Both sections test at ~30%. So he got me twice, once for the exorbitant price and once for a bad tube at that price.
I'm posting this to warn you to test all tubes that you might have bought from Mikhail. There is a good chance that some/many of them are bad.
The good news is that now that my Extreme has been made reliable (and better sounding) and finding out about this tube, I've worked through all possible things that can go wrong with Mikhail. I'll never buy another thing from him so it's now a great day and I can move on to better things.