I got a hummer!

[442w30]

I picked up a Marshall JTM30 amp because I thought I wanted less power than my 50watt combo, 2 channels and reverb.
Anyway, the clean sounds real good, but the boost or hi-gain channel has a hum at al volume levels. The hum is the same regardless of guitars or cables, so I changed out all of the tubes. The hum is still there.
The volume pot on the gain section is not original, so I thought maybe it is hooked up incorrectly or something.
Any suggestions?

[tonemonster]

Re: I got a hummer!

qoute: "I got a hummer!"

Cool!!! now can I have her phone #??? [img]/images/graemlins/poke.gif[/img] [img]/images/graemlins/tongue.gif[/img]

just had to do that.

Someone here should be able to hlep you with that, there are alot of sharp amp guys here on the board.

[Shotgun]

Re: I got a hummer!

I had a hummer once. Then I got married. [img]/images/graemlins/eyes.gif[/img]

Keith

[thenine]

Re: I got a hummer!

IF it is old, I would replace the caps. Electrolytic caps on power amps dry out over time, then the amps hums like mad. Replace all the power caps with the same values and see if it goes away.


9

[442w30]

Re: I got a hummer!

It's a 1995 vintage amp, sounds too recent to need caps to me (cause I'm old) but I guess it's near 10 years old. Do ya think caps would go that quick? I know the mid 1980s stuff typically needs recapping nowadays, but I'd think this is too new, but I don't really know. I;m going to peek in there to see if there are any that look leaky or damaged, then probably drop it off at a Marshall tech if nothing obvious comes up.
Thanks for the leads/advice!

[Enigma]

Re: I got a hummer!

[ QUOTE ]
I had a hummer once. Then I got married. [img]/images/graemlins/eyes.gif[/img]

Keith

[/ QUOTE ]

LOL classic!