I have a mac 4275 receiver which is from the late 80's/early 90's. It's almost laughable how good it sounds.
I also have completely stock 30 y/0 mr71 (tube), mr78, and mr80 tuners. They all sound magnificent. I bought the 71 from the original owner who only changed the tubes and had it aligned once. I can play these side by side with my hotrod scd-1 and my arc ph3 sources and they are sonically in the same general keeping (the sony rules). I'd say they sound better than 90% of the cd player's I've heard.
I do note that my 1990 denon receiver finally started to have noise with some of the inputs - probably from too many connects/disconnects. On the clean channels it sounds pretty good. Mass midfi, but good.
I would definitely stay away from the cheaper stuff.