What you describe sounds like an oscillation in the audio chain, preamp or amp. Could be caused by cables/interconnects, maybe? But that aside, the only “sound signature” I’ve heard as an indication of marginal/old capacitors was in my old Adcom 555ii where I could hear a slight “farting” sound when the unit was powered off and an slightly degraded bass response.
P.S. I assume it’s an SS amp given the weight but microphonic power tubes “can” also give the “fuzz” sound sensation, based on my limited experience.
P.S. I assume it’s an SS amp given the weight but microphonic power tubes “can” also give the “fuzz” sound sensation, based on my limited experience.