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Hey guys. I just stumbled onto this forum and you guys seem to know a thing or two. I've got a bit of an issue that i can't figure out.
I've inherited this basket case of a Carvin Legacy. When I received it there were no power tubes in it and the output board was fried (appeared to be a filament short since that pin on v7 was melted clear through the board also knocking out the filament 100 ohm resistors). I got carvin to send me a new output board and popped it in and plugged up with a new set of EL 34s. Got the bias to about 38ma and all looked well. Started to play through it and the volume was very low. As I turned up the volume a loud popping/squealing sound started coming out if I played more aggressively and if i played lightly the volume was still very low/compressed.
I couldn't find a single bad component in the amp save the OT. The OT measures about 35 ohms from B+ to either plate. That seems normal, but B+ on the tranny to ground only measures about 25K ohms. That seems very low and kinda like a short in the OT core.
My question: Does this sound like a case of dead OT or do you guys think it might be something else? If you've seen this before, you help would be greatly appreciated.
PS - I don't claim to be an amp tech. I'm a guitar tech by trade but I do most of the work on my own amps. I would like to get this one running without buying needless parts.
Thanks in advance!
Jon B
I've inherited this basket case of a Carvin Legacy. When I received it there were no power tubes in it and the output board was fried (appeared to be a filament short since that pin on v7 was melted clear through the board also knocking out the filament 100 ohm resistors). I got carvin to send me a new output board and popped it in and plugged up with a new set of EL 34s. Got the bias to about 38ma and all looked well. Started to play through it and the volume was very low. As I turned up the volume a loud popping/squealing sound started coming out if I played more aggressively and if i played lightly the volume was still very low/compressed.
I couldn't find a single bad component in the amp save the OT. The OT measures about 35 ohms from B+ to either plate. That seems normal, but B+ on the tranny to ground only measures about 25K ohms. That seems very low and kinda like a short in the OT core.
My question: Does this sound like a case of dead OT or do you guys think it might be something else? If you've seen this before, you help would be greatly appreciated.
PS - I don't claim to be an amp tech. I'm a guitar tech by trade but I do most of the work on my own amps. I would like to get this one running without buying needless parts.
Thanks in advance!
Jon B
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