Gr8Scott
Wookieologist
I have a set of Tesla EL34's in my Butcher that suddenly started to blow the heater fuse in the amp. I think one of them shorted out. When I originally installed the tubes, they biased nicely at about 35 ma and remained steady there. The amp sounded huge and it kept this awesome sound until it started blowing the fuse. I tried running two tubes by themselves, but it just sounded dark and crappy. Very spongy though and the volume was markedly lower. I probably have about 20 hours of playing time on these tubes. The heater fuse is 8 amps, which should be more than enough to support the quad of EL34 tubes and the three 12AX7 tubes as well. I didn't re-check the bias after only 20 hours, but the tubes seemed to hold bias very well initially after I installed them. I did re-check after the first hour of play time on them to make sure they were holding firm and they were.
After inspecting them a bit, I see a bit of light brownish discoloration on the glass by itself just below the getter flash around the top of the tube. The discoloration is not touching the getter flash, but it is close to it. The getter flash is still silver and is slightly darker than when I first installed the tubes.
My only experience with blowing output tubes happened when some poorly made chinese KT-66 tubes lost vacuum and died rapidly on my Edana. I've never had a set do this before.
I have a couple of choices to replace them with. I have the EHX EL34's and JJ E34L's. I've heard good things about the JJ's sound, but they are not the best in terms of microphonics and may be damaged by too much mechanical vibration. I'm running this head without an enclosure at the moment while I have a friend make me a new lighter enclosure, so mechanical vibration is a definite consideration while I'm waiting.
Being a tube junky has it's merits at times. I didn't even know I had the JJ's and thought I had sold the EHX tubes with one of the amps I sold a while back. I completely forgot I had two quads of matched EL34 tubes waiting to replace the Tesla tubes that burned out.
After inspecting them a bit, I see a bit of light brownish discoloration on the glass by itself just below the getter flash around the top of the tube. The discoloration is not touching the getter flash, but it is close to it. The getter flash is still silver and is slightly darker than when I first installed the tubes.
My only experience with blowing output tubes happened when some poorly made chinese KT-66 tubes lost vacuum and died rapidly on my Edana. I've never had a set do this before.
I have a couple of choices to replace them with. I have the EHX EL34's and JJ E34L's. I've heard good things about the JJ's sound, but they are not the best in terms of microphonics and may be damaged by too much mechanical vibration. I'm running this head without an enclosure at the moment while I have a friend make me a new lighter enclosure, so mechanical vibration is a definite consideration while I'm waiting.
Being a tube junky has it's merits at times. I didn't even know I had the JJ's and thought I had sold the EHX tubes with one of the amps I sold a while back. I completely forgot I had two quads of matched EL34 tubes waiting to replace the Tesla tubes that burned out.
