Ok so I got a new guitar today (epi g400) and plugged it into my peavey aud 20 and it all of a sudden started to freak out after about a minute of playing. Why so? It can't be the guitar, it works fine in my other amp. BUT i used my other guitar on the peavey and it works fine. What is going on?
"freak out" isnt helping us at all, maybe a little more detail of what happened?

Mitchell MD100S
Yamaha CS40
Dean V-Coustic
Laguna LE122

Line 6 Spider III 15W
LOL yes, more detail please.
Was it a high pitched noise?
100w Peavey Valveking Head
Mesa Rectifier 4x12 Standard Cab
Ibanez RG 321
Boss DD-7
iSP Decimator x2
BBE Boosta Grande
Modded Crybaby
MXR Blue Box
Numark Power Conditioner
Korg DTR-1000
Um well it was playing clean then stopped working totally. Then started to work in a lower tone. Then it would go from one sound to the next. I'm not really sure how to describe the sounds, kind of like when you turn the treble all the way up on a car stereo and everything down.