I've got an Epiphone Valve special that I bought a fair while ago. It's currently gathering dust due to a problem, and the fact that I've long since moved on.

When the amp is powered on, warmed up, and then switched from Standby to play, it makes a horrible hissing noise. It's always been started in standby and allowed to warm up properly before being used etc. It also makes the same hissing noise when it's turned back from play to standby.

Once it's switched on, it performs like it always did no hissing, and its like a big valve junior with a bigger speaker, some EQ controls and some pretty poor digital effects.

I've changed all the tubes recently, and that didn't make any difference unfortunately, I know very little about amps so I was wondering if anyone has any ideas as to what might be the problem and if it's fixable.

I'd like to get it running properly again to give to the kid next door who is really getting into his guitar and is currently using an awful starter pack amp. I don't really want to take it to a tech, as I am looking at giving it away and don't want to spend any more money on it.
try spraying contact cleaner in the switches. It may just have some dust/grime in it from not being used.
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
No, this is an electrical hiss which lasts for a couple of seconds and fades out. Sorry should have made that clear. It was also doing it when i replaced it.
Could be a valve problem possibly?
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