#1
Okay, I have an original '68 Ampeg Gemini 1x12 all-tube combo.

Lately I have noticed this when turning it off. Theres this odd growling noise.

I'll throw the stand-by, then turn the power switch off. When I do, it sounds like a distorted gggrrrrRRRRRRRrrrrrgggg. Like a distorted, flanged, growl. (and this is without any pedals in my chain, just guitar-->>amp.) I would post a sound clip but dont have anything to record with.

Anyway, based on the info, what would most likely be the problem? Or does this happen just with age?
#2
caps?
Gibson Les Paul Custom
Fender American Tele

F/S:
Orange Rockerverb 50
Orange PPC412
#3
I dont think so. I dont smell any burnt dielectric or anything. Although that doesnt rule caps out by any stretch.

Could it be rectifier or weak tubes?
#4
Don't try and touch anything inside the amp. You could dieee


Take it into a technician. Messing with tube amps is never a good idea.