Pulled the chassis out of my H&K Tube 20 the other night and measured 407 volts on the plates of the EL84's (pin 7). Wow. What is that about? I was expecting maybe 350 or so. But 407? I guess the JJ EL84's I have in there won't last long at that voltage. Maybe I should order some of those Sovtek EL84M's or find some 7189's. What do you guys think. Should I worry or just be prepared to replace them every few months or so? Guess I need to order a bias tool and make sure the bad boys are biased correctly. They aren't redplating and sound great to tell you the truth.