Gregadd, Hmmm... Good points, all. I do agree that the vintage system you describe would acquit itself very well against systems today. As you note, quality of materials is probably the biggest change. My "modern" preamp uses a classic audio circuit with 12AX7 tubes: biggest difference from a Marantz 7 is power supply and parts quality.
And for source material, I'm listening right now to a 35 year old piece of vinyl that sounds as good as any contemporary recording, and probably better than most.
And, I'd have to say that the system I'm listening to tonight sounds qualitatively better than any I could have assembled 20-30 years ago, but the cause for that is mostly in execution of the design, not new design, and quality of materials, not the result of anything radically new.
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