I know over the years, I've listened to quite a few vintage receivers,
many of which were Marantz from the good old golden '70's, and honestly,
many of these sounded like crap to me, regardless of how pretty they
looked, and that on some, having 3 tone controls (Bass-Mid-Treble)
seemed more a detriment, than a help.

Didn't seem to matter what you did with the controls, I never could get
a satisfying sound with them. Maybe an outboard EQ would've helped in
these particular cases?

Maybe then again, nothing would resuscitate them? lol Mark