Tube Amp Archive

thanks all,
I have done what everyone has suggested. In the end, I can not attribute it to anything except a bad tube. I'm now running - about 3 hours on a new pair. Hopefully this will not recur.

thanks,
Dave

ok, after resoldering tube and testing in the basement, all seemed to be fine. take it to gig and crackle, then fuse blow on first song. I can only assume it was redplating again, but don't know for certain. Is it foolish to hope that maybe one of the power tubes had become bad? Aside from re-checki...

thanks, I will try that too.
yes, I should have mentioned this is a kit.
Dave

thanks - I tried swapping tube and I can't recreate red plateing - not even in same socket. Once I got some sizzle coinciding with notes I played, but reseating the tube seemed to do it. Wiggling the tube in socket seems to casue a bit of crackle, and once chopsticking some wires on the socket cause...

I haven't had a chance to double check on this yet - but last night my allen encore was making a crackling sound at the loud range of my volume pedal. For some reason I whacked it on the top, and crackle heard again. For some reason I looked behind, and noticed the 6L6 furthest from the rectifier tu...

hi, a friend is bringing over his marshall stack tomorrow. Apparently, it has gone to half volume at least once. He thinks the tubes stop glowing when this occurs. I thought I would start by chopsticking all board/tube/output txfm connections and hope that something is loose. Any other suggestions? ...

ok, I will check plate voltages tonight and repost. I have been using electroharmonix 6v6 from wherever they might come from. Thanks for your help.
Dave

does anyone have an idea why my vibrochamp blows power tubes about once every 6 months? I don't use it terribly much, but this has happened twice now. When I has died I have been running it all out, more or less. I can get some voltages later tonight - just wanted to prime the pump and see what peop...

ok, I will proceed.
thanks!

hi, just assembling an 18watt build. I have not insulated the pots, so they are in electrical connection with the chassis. Undaunted, I added a wire buss across the backs of all pots and will use this for pot leg groundings, and grounds for the board. two questions - Is the pot physical connection t...

I've actually run mine for an entire 3 hour gig like that. I noticed it was dirtier than usual when I turned it on, but didnt' realize until the next day that a tube was missing! Seems to be no ill effects... The amp also handled the beer that was spilled into it as well. Hopefully you will have sim...

well, the coolness of the tube closest to rectifier follows the tube. After switching, the same tube runs cool in a different position. 6.2 V AC across pins 2 and 7, so I guess the filament voltage is getting there. Is this good enough to say bad tube and junk it, or would I try to measure the AC ac...

ok, on both power tubes here are the voltages - closest to rectifier: closest to preamp tubes pin 3: 494 pin 3: 495 pin 4: 493 pin 4: 494 pin 5: -49 pin 5: -49 pin 6: 494 pin 6: 493 now, the crazy thing is, is that the 6L6 closest to the preamp is nearly cool to the touch. Even after being on for a ...

hi, what's the best way to solder 2 pieces of wire together? I would avoid this if possible, but sometimes it's necessary - like when the leads of a transformer are too short... generally, I try to wrap the ends around each other, solder 'in the air' and shrinkwrap. probably better, but more space-c...

thanks for the comments - I'll yank some tubes later tonight if still malfunctioning. This buzz is an extremely loud honking - not a tone really, but quite loud - even with volumes down. Like the sound of the jack being plugged in/out with the volume up. But continuous, as I say.

more later,
Dave