Did the Old Receivers Sound Good?

True. Electronics have come “a long way.” Todays electronics are wave soldered using micro component SMDs and SMD semiconductors, robotically positioned on the computer designed boards, from computer designed and modeled circuits. 
 

The old stuff was designed by hand, individual circuits using discrete components.
 

Yeah, we’ve come a long way. But not sonically.

There’s more to this than just the specs - I have a vintage system of Sansui AU-9500 with JBL L65 & Luxman TT at my summer place. It’s equal parts nostalgia/performance but it brings me just as enjoyable an experience as when I’m listening at home in my dedicated room. That vintage system fills the place with great music and good times. I can say emphatically that the vintage pairing of Sansui and JBL has a magical quality. Like a time machine for me... STILL sounds amazing and yes, all the vintage pieces have been upgraded and redone by a fabulous shop in Massachusetts that specializes in "better" vintage gear. So, maybe not better, but not worse - just different although equally enjoyable. Just my opinion.

You really can't compare the vintage receivers to modern receivers even if you put modern caps and resistors, it changes the original sound of the vintage receivers when this is done.

That could be another comparison. Put new old stock capacitors in an older piece of equipment and then have modern capacitors and other components installed in the same piece of gear or a second identical unit just to hear the difference.

All great responses! Where to start! Testing specs don’t really show much. Distortion is low in vintage amps and modern gear. Noise floor has improved with preamps. Transistors in well made vintage amps had carefully selected transistors. transistor quality control was not as good as today. They tested matched transistors for each amplifier for high performance. Upside of the times.

Today they don’t, good enough mindset. Now there’s class D etc.

Kenwood KA-5500 is a great sounding amplifier! ST-70 I was never big fan. Same with the Mark III mono blocks. They made clean tube power, affordable or used to be lol.

Pioneer SX828 is great sounding unit. Favorite receiver from Pioneer to be honest.

Sansui makes some great gear too!

I’m not one to replace resisters for no reason. Capacitors I do change, in theory there supposed to sound like the specs. Tired caps change the sound as new production caps would. All part of the fun. When I recapped 7T, earth shattering change. I kept the resisters, changed the diodes, caps etc. Made such a huge difference. Transistors used in the 7T were selected for performance, no reason to change those ever unless there noisy / failed