some 70's and 80's receivers seem to be popular

That harsh, bright and "listener's fatigue syndrome" effect came about when the Japanese starting using lots of negative feedback to further lower the distortion figures. It seems that during the 70's and 80's there was a competitive factor involved that made some manufacturers strive for "who had the best specs", rather than "who had the best sound". I still have a mid-70's Harmon Kardon 730 that is very musical for its time, though. I recall selling an early 70's Sherwood receiver to buy the newest and latest receiver design from Technics and regretted it immediately when I got it. The sound was like beams of lazer piercing my eardrums. Ouch! I couldn't get rid of it fast enough.

I highly recommend you pick up a 70's 22XX Marantz Receiver in good working order and you will find out how good they sound. (I have the 2218 model. Very Musical) I also own a Sony VX-5 receiver which I modified w/new power cord/binding posts/a high quality power rocker switch. You would be amazed how good it sounds. Exc. phono and FM tuners in these Receivers.

My brother has vintage a Marantz 250 power amp and 3300 preamp driving Paradigm Titans. His digital source is a Bose wave radio. What I thought was going to be an old mans "dream system" sounded detailed yet musical with no fatigue. He did have both pieces recapped and cleaned. Total system cost was about $1500. Sherod is correct about the lack of negative feedback. Check specs on the early 70's Marantz components...distortion is relatively high. The Marantz 2270 I have shelved in the closet will become my new "second" system after coming back from the audio doc!

.
Sansui 771 or 881 will anchor a nice second system.
.

The brands mentioned above were/are very good.

I've owned Tandberg and Yamaha in recent years and both have delivered the sonic goods in my second, two channel A/V system.

The Advent 300 was another very good sounding though finicky piece.