high pitched squeal from my peavey XXL combo?

[peaveyman001]

I recently purchased a used peavey xxl combo at GC for a great price. I love the tone and the options it has but when I crank the volume, I get a squeal that can cause hearing damage. I know with tube amps, a tube can cause this but I've never heard this problem from a SS amp. Anyone have any suggestions??

[Enzo]

Don't plug anything into the amp except a speaker. Does it still make this noise when turned up?

Now plug a guitar into the input, but turn the volume control on th guitar down to zero. Turn up the amp, does it still make the noise?

And when you try to play at whatever settings you use, does it matter if you walk away from the amp and turn sideways with the guitar?

[peaveyman001]

Thanks for the reply...

ok, amp by itself made no squeal.

amp with guitar into the input with guitar volume at 0, i also get no squeal.

When guitar volume is up, theres the squeal. Walking away or not facing the amp at all makes no difference.

Also, i tried different cords (one being mogami) and guitars with different p/u's (active EMGs and SD jb).