Peavey XXL 212 making hissing noise!!!

[ryanorono]

Hey, I'm just wondering if any can tell Me why my amp is making a hissing sound when I turn on the two gain channels? I've turned down the gain and it helps a bit, but I loose a lot of volume and tone. Also I've tired switching the ground to "+" and "-" but it still hisses and it's frustrating!!!

If anyone can help me it would be greatly appreciated!!

[J M Fahey]

All amps hiss; much more as you use high gain.
Without actually hearing it  can't really say.
To know if something is grossly bad with yours: set tone controls to please you, then start with gain/volume on "0" and rise it until the power amp just starts to clip, so you find the maximum "clean" gain/volume.
Now turn guitar volume and tone down to "0".
Can you hear any hiss?
Is its level disturbing?
If you hear a *slight* hiss (practically needing your ear close to the speaker), it's normal.
Of course it will be multiplied by gain.