Squeeling amp

[ailean]

My Peavey ValveKing has started squeeling when it's switched on. Not every time, sometimes the problem will go away if I switch off and back on again.

It's louder when a guitar is plugged in but always there, the volume control affects it so I'm assuming it's before the power amp stage. I've swapped cables and guitars and the sound persists.

The sound is (as best i can describe) a cross between static hiss and squeel.

I'm hoping this is a tube problem, but can you get intermitant problems with a tube or do they just blow?

Any advice would be welcome, I've not had much experience of a tube amp, and the only thing I know about them is they sound good!

[hunter]

Sounds like tubes to me. Pre- or Power, hard to say... I'd bring it to a tech to have checked.

[maverickf1jockey]

Are you using a distortion in front of the amp?
I have a similar problem and it's to do with the pedal feedbacking at high gain.

[Twinfan]

Sounds like a pre-amp tube to me.  Try swapping their positions around and see if helps/makes it worse.  If it does, get a set off JJs in there  ;)

[Fourth Feline]

Sounds like a pre-amp tube to me.  Try swapping their positions around and see if helps/makes it worse.  If it does, get a set off JJs in there  ;)

Agreed.

Gently tapping the side each pre amp tube with a pencil usually reveals the culprit. I had very similar symptoms/outcome with my Peavey 'Classic 20'  some years ago. From the factory they had poor quality pre-amp valves. Hope it works for you .

F.F.

[ailean]

Thanks guys. I'll have a play.

Maverick - No, nothign but guitar and amp.