Can a gain knob cause amp to cut out

  • Thread starter Thread starter ido1957
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ido1957

ido1957

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I was playing with my Marshall 4100 today. It started to buzz and fuzz and then it lost a bunch of volume like the standby switch had been engaged. You know that gradual distorted fuzziness and volume drop you get if you keep playing while you turn it off....

Anyway I checked a few cords and bypassed my pedal and it still happened - sort of intermitently, but consistently.

The I turned the gain knob on the amp and it crackled badly. I turned it back and forth repetitively until most of the crackle went away. The I did the same to the master but it wasn't near as bad.

That fixed it! It never cut out after that and I played for another hour or so.
Can't say whether the problem might reoccur though.

I had this happen when I was playing new year's in 1999-2000 and did half the night with almost zero volume. I took it to the shop and they said the head was fine. It just started doing this again today.

Anyone out there ever heard of the gain knob being responsible for this cutting out problem? It sure sucks the groove out of you when things don't work properly....

:D :) :D :)
 
Yes, they do that.

Lubricate your knob (oo-er!) and the crackling should stop (oo, missus!)
 
Well I fired the amp back up after posting above, and it started doing it again. Did some more knob jiggling and thumped it on the top of the head and it settled down again.....lasted as long as I needed it to but I'm wondering if it needs servicing.....
 
Dont bother with servicing if all you need is a pot cleaned....

Get a can of DeOxit, open up the amp, dismount the pots so you can spray a little bit of DeOxit inside them, turn each one back and forth about 100 times after you spray it, then put it all back together again.

It should cure the problem. If not, then the pot is not the problem. Are you sure the tubes are good?
 
soundchaser59 said:
Dont bother with servicing if all you need is a pot cleaned....

Get a can of DeOxit, open up the amp, dismount the pots so you can spray a little bit of DeOxit inside them, turn each one back and forth about 100 times after you spray it, then put it all back together again.

It should cure the problem. If not, then the pot is not the problem. Are you sure the tubes are good?
Click to expand...


That should cure the problem, but be careful not to touch anything in there while you are doing it. There are some bad shocks inside a guitar amp.


Light

"Cowards can never be moral."
M.K. Gandhi
 
if that doesn't work and i expect it wont... then what is mostlikely is you've got bad coupling caps associated with those circuits.... the crackles are the pot trying to pass the DC...
 
i had an amp that would do that and it turned out the input jack wasn't latched down. if that is the poblem get it fixed now or the weight of cord will end up breaking the circuit board. i hope for your sake the circuits are just dirty and need a good cleaning. in that case do the affore mentioned deoxit spray.
 
Bad pot is well...a bad investment. Everytime I turn on the amp(s), I give every knob a full clockwise and anticlockwise rotation. Letting them sit without moving can leave nasty deposites and eventually permanant wear. Over-use...'bout the same. Keep them clean, exersize them you'll be fine.
 
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