Use EL-34s or 6AC7s? Does it matter?

Hello!
I have a 210 Sixty Five amp, in the process of being re-tubed.
Mike Kropotkin of KOS tubes had mentioned to me that EL-34 tubes may be a poor fit for MM amps, due to the high plate voltages of MM amps. He recommended 6AC7s instead.
What are your thoughts? What experiences might you have?
Does it matter which type I use? Originally, I had thought that these were virtually identical tubes...
Thanks much for any ideas...
Richard

Many EL34 type tubes won't stand up to the high plate voltage found in Music Man amps. From all reports, the JJ EL34L tubes hold up well (and sound good too). Remember, if you play in the low power position most of the time, almost any EL34 will work becuase the plate voltage drops to 400Vdc or less.
I have also heard that Svetlana and Sovteks generally hold up well, but if you get one with loose internal elements these may arc-over if the amp is vibrated, shocked or dropped.
The 6CA7 is a better tube for these amps (designed with wide-element spacing and larger plates), but they are generally more expensive and harder to find with the possible exception of the Electro-Harmonix 6CA7EH currently available.
The Groove Tubes 6CA7GT is a US made tube and probably the best currently manufactured variety, but they are spendy!
Steve

Hi Steve, just wondering im thinking about replacing my 6CA7EH when there time is up with the US 6CA7GT - how can i tell if they are the real deal and not the cheap GT's out there?

If you are really serious about 6ca7's, you should only go through a reputable dealer like Mike at KCA. If you want great tubes at a decent price, try the JJ's in the E34L variety. They work well in my MM's and last. There are too many sleazy buys out there any more to trust getting "the real thing" without knowing what you are doing. Try mike if you are serious about NOS but be prepared for sticker shock!