I agree...older stuff can sound better for the money, but like usual, there are exceptions. Old receivers are a good buy for a cheap 2nd system. I think preamps have improved over the years, but I say that based on my experience with an old Luxman C-1010...it's very smooth and fun to listen to, but not necessarily neautral or extremely transparent.
On the other hand, I was once in a used audio shop that was running an early 80s (late 70s) Pioneer preamp (huge, and probably their top at the time), with two Marantz THX monoblocks (the very small, long ones), and a pair of homemade monitors (Rogers copies). They played "Take Five", and it sounded great. Huge soundstage, and very transparent. I was surprised.
On the other hand, I was once in a used audio shop that was running an early 80s (late 70s) Pioneer preamp (huge, and probably their top at the time), with two Marantz THX monoblocks (the very small, long ones), and a pair of homemade monitors (Rogers copies). They played "Take Five", and it sounded great. Huge soundstage, and very transparent. I was surprised.