Re: 6BM8--is it an EL84 or EL82?
6BM8; used a lot in 60's Japanese TV's, but kinda scarce and expensive now...EL 82 (pentode) is a different tube from the ECL 82/6BM8 (has a pentode and triode section). And no---you can't sub an EL 84 without rewiring the socket and a few other things.