A buddy's Parents had some Bose shelf speakers from the 70s. Not sure if 501s or not as they had multiple series but he still has them. I camp with him every January and when i asked him last year if he still had them he said yes and still sounds just as good as the day he bought them. Bose is the stuff man.I still have the Akai reel to reel and the Sansui receiver, matched with the original Bose 501s. I haven't seen anything to match those. We had a Dual turntable that I'm trying to replace (ex wife took it to Salvation Army). Hard to match that old quad 4 channel sound.
