JCM800 grounding issues?

J

jrlemonz

New member
That same amp I mentioned how much I love its tone, already hate its maintenence. When I play out of it sometimes it'll start humming like it isnt grounded, and the volume will drop VERY significantly. It'll go away sometimes, sometimes it wont, and I have to leave the amp to cool down completely and turn it back on. Its really weird, and quite annoying. I figure its something that happens when it runs hot, but sometimes its running at a really loud volume for quite some time, and nothing happens. any ideas? I've tried plugging it into different outlets, differnt cords everywhere (it makes the hum whether the guitar is plugged in or not when its humming). I don't get it.

Jake
 
sounds like a Cold Solder joint (most likely).

or

a tube socket connection problem (next most likely).

or

a tube failing (least likely).

try this - the next time you loose volume take a clean rag and wiggle each tube in it's socket. see if the volume and Hum are affected.

it really sounds much more like a cold solder joint. if you're not skilled in amp repair, take it to an amp repairman and describe the problem. he'll need to put it on his bench, fire it up, wait for it to fail, and then start looking for the wire joint problem.

another method, which i've used quite a lot on point-to-point wiring it to re-solder each tubes connection. it doesn't take that much time to do and is fairly risk free, but your JCM-800 is not point-to-point, but maybe re-heat the tube socket connections.

-kp-
 
It's probably the cold-solder thing, cause I've tried wiggling the tubes around, it doesn't affect it at all. I'll bring it to a repairman.

Jake
 
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