GK 1001RB-II hisses/screams even with muted input

[Mobile Sprout]

I have a problem with my GK 1001RB-II. I have been using this amp on and off for around four years and have never had a problem with it. I keep it in a soft case, I never expose it to smoke or water.

About a week ago, without warning, the amp suddenly started producing much much more noise. Assuming it was my bass pickups, I unplugged my instrument and muted the amp input, but the hiss persisted. When I turn up the volume ("woofer" and "boost" to noon or greater), the amp lets out an eardrum melting scream! (still with no input)

Any clue what is wrong with my amp?

[funkybassinator]

While you'll probably just get some speculative stuff on here (unless Rob Gallien chimes in), I'd call GK. I've heard of them not replying to emails much, but calling always seems to do well.

[IbanezSGfan]

+1 @funkybassinator, awesome customer service.. that definitely sounds like a sticky situation though.