I can't speak for other brands, but I owned several vintage Marantz receivers, and to me they sounded smooth and pleasing, if a little lacking in dynamics. That was a pretty good achievement for that time though, because a lot of the solid-state gear then was anything but smooth.
Did the Old Receivers Sound Good?
Before the high end started, we had all these receivers and integrated amps from Pioneer, Kenwood, Sansui, Sherwood, etc., all with incredible specs. Then somehow we decided that specs didn't matter and we started moving to the more esoteric stuff from Ampzilla, Krell and whoever, but the specs were not as good. My question is - Did the old Japanese stuff with the great specs sound better? I don't remember. I'm asking because many seem to be moving back to the "specs are everything" mindset and I was thinking about all that old stuff with so many zeros to the right of the decimal point.