Marshall jmp 2204 annoying problem

[FleshOnGear]

Do you still get the "fuzzy" sound if the gain is backed off a bit? In, other words, does the problem only occur if the gain is maxed? If so, sounds like it could be an oscillation issue which can be sorted with improved lead dress or shielded grid wires.....or just backing off the gain until it stops. Hope that helps.

Yeah, in my experience oscillation often sounds like fizz on top of the normal signal. Sometimes the normal signal sounds kinda choked, too.

 

[Petejax1234]

Ye thanks for the replies guys. Maybe it was an oscillation issue. I took it to a different tech who bench tested it and he said there’s nothing wrong with it. So maybe it’s just me or the way I’m setting it up I’m really not sure. All I know is I have an early 80s jcm800 2204 and that sound out of this world however I set it.

 

[FleshOnGear]

Ye thanks for the replies guys. Maybe it was an oscillation issue. I took it to a different tech who bench tested it and he said there’s nothing wrong with it. So maybe it’s just me or the way I’m setting it up I’m really not sure. All I know is I have an early 80s jcm800 2204 and that sound out of this world however I set it.

Same volume and gain settings and the guy couldn’t get it to mess up? Are you plugging straight into the amp when the problem happens?

 

[Petejax1234]

Same volume and gain settings and the guy couldn’t get it to mess up? Are you plugging straight into the amp when the problem happens?

Straight in to the amp is yes. I’m obviously hearing something that atleast these two techs are not. Anyways I’ve traded the amp in against an old guitar and the new owner seems thoroughly happy with the amp.

 

[paul-e-mann]

No, the tech is saying he hasn’t got time to go near the amp for atleast a month as he’s crazy busy. Looking at the invoice about the only thing he didn’t do was change the filter caps. Could be a cold solder joint even I guess. This amp is an absolute beauty and I’m sure it’s something very minor, just very annoying

If you can't strong-arm him to do the service now play it for a month and bring it to him when he's available, and rip him a new one for not doing a proper service for that money in the first place and don't pay him a penny more to get it right. What did he really do for 400 bucks??

 

[FleshOnGear]

Straight in to the amp is yes. I’m obviously hearing something that atleast these two techs are not. Anyways I’ve traded the amp in against an old guitar and the new owner seems thoroughly happy with the amp.

Sorry it didn’t work out. Is the guitar nice?

 

[Petejax1234]

Sorry it didn’t work out. Is the guitar nice?

Mid 60s candy apple red jag, it’s an absolute beauty and I’m in love.

 

[Trumpet Rider]

I love a happy ending.

 

[TM1]

I would bet that the Bias is off. Which Bias control does it have, an up-graded trimpot or the square slider pot? The slider pots are famous for going wonky.

 

[mickeydg5]

Does the PRESENCE control operate properly?

 

[Petejax1234]

Does the PRESENCE control operate properly?

sold it a while ago

 

[matttornado]

Man if i were your tech, i would have felt embarrassed, i would have apologized and taken it back for immediate repair free of charge. if it needed caps, i would not charge the labor.

 

[mark123]

Threads like this one is why I fix my own amps now. Most “techs” are tube swappers and little else. The worst part is when they talk to you like they performed rocket surgery after replacing a phase inverter tube.

No one is ever touching my amps ever again.