Not surprising about the Sansui QR-6500 pairing well. It's been expressed many times that these HP have excellent synergy with a lot of stereo's from the 70's. Marantz is another known brand that pairs as well. Course the 70's produced some of the best audio products to this day, so I suppose this shouldn't be surprising at all. lol
I love the seventies too, but I hope you're not comparing stereos based on the headphone jacks. If you wand a stereo with a less attenuated hp jack you just have to deal with different companies. Even though most of the old companies that made good stuff back in the day have sold out, doesn't mean a hifi amp from today wouldn't rip it's older sibling a new one. I agree that for the money you get more with an old Sansui. However if you spend some cash and buy a higher-end home amp then you'll get something made for more than walkman headphones. And with the amount of money you save on your electric bill, the newer product will pay for itself before it dies.