GK MB500 amp making a funny noise...

[lastanthem88]

Well actually, it's not at all bloody funny, it's highly inconvenient seeing as gigging resumes for me at the end of May... 

I've had this amp head for four years, it's always been great. Out of the blue a week ago, half way through me practicing at home it started making a very high pitched continuous buzz. In fact it's more of a squeel. 

It gets louder when I turn the amp up. An electrician friend of mine opened it up, he's always fixed things for me before (PA systems, dodgy pedals, tone pots, etc etc) but has said he can't find the problem.

Can anyone help, or point me in the direction of someone who can? I'm in Middlesbrough.

Thanks all. 

[Bigguy2017]

Could be many things.

First place to start is dried out electrolytic capacitors.

Have a real good, close look at all the electrolytics, looking for doming, swelling or leakage.

A duff decoupling cap could be the culprit.

[lastanthem88]

Thanks for that!