I don't hear anything but music and this is the wrong way to track down a issue..
Try no source with functions on a source then slowly gain up..
What do you hear?
Slight hissing sound? Interduced noise from poor connections, cabling, function and or RCA jack connection issues. More likely bad electrolytic cap in the tone OR source function like phono stage , tape loop ect.
A pop crackle as you gain up?
Your receiver is a real Pain in the Ass to service, too much crap in such a tiny confined box..It's vari matrix, dolby, record loop system is very good IF it is fully restored and scope plot checked for little issues that cause many slot of grief ..
Mine fully restored including the FM front end is 100% noise free as in no source plugged into source socket and gain turned way up= zero noise heard on speakers..I'd say you and others are going to be in this same boat with odd sounds until you have the whole system completely stripped down and every board completely gone through including scope test for noise..
I use strictly vintage matching speakers that are 92 db or better..The B&Ws are big offenders to vintage receivers, better suited on my big class A Krell amp.
