[Amps] 3-500Z parasitic wows

[John]

Hi
  I have been around a lot of amps .....   Every amp that had a parasitic
blowup episode used a 3-500Z  . I'm talking TL -922 , SB-220 , AL 80 , AL
80a ,AL82,  SB-1000 , Drakes, Viewstars & more ... If it has a 3-500z
....it WILL someday hand grenade,  I had two go off next to me , my friends
SB220 & AL80.... blowing parts everywhere & dreaded grid to filament
shorts.......I have no confidence in that tube. Every time I use an amp with
a 3-500z in it , I am waiting for the big bang .....

John