Marshall squealing?

wylie · Post by **wylie** » Tue Nov 01, 2005 12:51 pm

I have a small Marshall JCM800 tube amp.
The other day I had someone plug into it and it started squealing I didn't think much about it "hot pickups maybe"
After playing around trying to get rid of the squealing a funny thing happened.
Turn down the guitar,nothing,unplug the guitar still squealing.I unplugged the cord from the amp and the squealing stopped.
So I though bad cord,tried another cord same thing.
So another cord and guitar still the same thing.
The amp by its self sits there quite until you plug a cord into it and it starts squealing?
I've never seen this before,any Ideas.Could it be a lose tube or something?

oldguitars · Post by **oldguitars** » Tue Nov 01, 2005 3:03 pm

probably a bad tube. Get a wooden chopstick, turn the amp on and tap the tubes until you find the culprit.

wylie · Post by **wylie** » Tue Nov 01, 2005 3:24 pm

Thats what I'm thinking its something that just started out if the blew

I'll try that and let you know.

oldguitars: nice collection you have there ether that or your living in a music store.
envy

oldguitars · Post by **oldguitars** » Tue Nov 01, 2005 3:40 pm

yeah, you will probably find it in the preamp section. Thanks, i think I have a gear problem, i think i need to go to gear anonymous. I didn't even include my drums and guitars.... i am a dork

wylie · Post by **wylie** » Thu Nov 10, 2005 8:43 am

oldguitars wrote:probably a bad tube. Get a wooden chopstick, turn the amp on and tap the tubes until you find the culprit.

Thanx OG that worked,it was one of the small tubes with a metal jacket around it when I wiggled it the squealing stop and is now OK.
I guess it was just lose.

wylie · Post by **wylie** » Fri Nov 24, 2006 11:21 am

OK I've finally givin up on this JCM800 after getting it repaired and it working fine for a few months it crapped out again in the middle of a session.
Now all of a sudden it started crackling at full V.
Its sad because we've gottin allot of great tracks laid down with this amp and it sounded great when it was feeling well.
Any how I can get a good price on a MG30DFX http://www.marshallamps.com/product.asp ... de=MG30DFX
Has any body used this amp?
I've used some of the Marshall solid state stuff in the past that I liked but don't remember the models.

YouTube · Post by **James Steele** » Fri Nov 24, 2006 11:24 am

wylie wrote:OK I've finally givin up on this JCM800 after getting it repaired and it working fine for a few months it crapped out again in the middle of a session.
Now all of a sudden it started crackling at full V.
Its sad because we've gottin allot of great tracks laid down with this amp and it sounded great when it was feeling well.
Any how I can get a good price on a MG30DFX http://www.marshallamps.com/product.asp ... de=MG30DFX
Has any body used this amp?
I've used some of the Marshall solid state stuff in the past that I liked but don't remember the models.

That's a bummer. Perhaps take it to a different amp tech and tell him the history of this. Maybe they can track it down?