EL34 and EL34B help

[matatak6]

can el34b's go in my amp that had el34 in them?

its an ashton vp50 combo
has 2 el34 and 4 12ax7.

thanks

[Rob Mercure]

Matatak,

Hmmm, I'm not sure that there was a "B" EL34 back in the days when the type designations were standardized and the specs "enforced" by the standards setting agencies (RMA/EIA in the USA). With that said, under the accepted standards any improvement to a valve design - designated by a letter suffix beginning with "A" under most of the coding schemes - should be "back compatible" with earlier versions. That is, a 6L6GC should replace a 6L6GA but not the other way around. So your "B" version EL34 should work fine. But out of curiousity who made 'em?

Rob

[TD_Madden]

Probably Shuguan (sp)...Ruby and ValveArts retail 'em.

[matatak6]

thanks for the reply...

am i correct in assuming that no damage will be done to my amp by putting El34B's where standard El34 used to be?(amp came new with EH EL34)
but i cannot put El34 in an amp that was made with El34B's?

i have changed the tubes (matched pair) and i keep blowing fuse as soon as standby is turned off. just thought it might be incompatible tubes since the ones i put in have EL34B printed on them.

they are made by ruby! (El34B)

thanks for help

[Steve Conner]

Those tubes should be compatible with ordinary EL34s. And a modern amp design like the Ashdown shouldn't have any of those vintage quirks like using spare pins on the tube sockets for totally unrelated things. So I think there must be something wrong with the new tubes, or with your amp.

Maybe one of the new tubes got damaged in shipping and has an internal short. Did you try going back to the old tubes and see if the fuse still blows? If so, your amp may have a problem.

What about with one old tube and one new tube? It's highly unlikely that both your new tubes would have got creamed in transit, so try them one at a time. If only one of them makes the fuse blow then there's your proof of a bad tube.