already have a 640 and was wondering if the 820 would provide any significant sound improvement over the 640...would then sell the 640..but, dont want to pickup said 820 if i really wont hear much of a difference, interested in the fm section and aux.tape sections...dont care about the phono section...

thanx!

Well, this will be entirely subjective, but my vote would be for the CR-820. Fewer integrated circuits, more discreet compnents (caps, resistors), and I'd be sure that the chassis, tuner (don't know exactly how many FM gangs are in the 820) and build quality is better with the CR-820. The 820 has more power, a third tone control ("Presence"--mid-range) and I think that it has a -20dB Muting switch too.

I think that the CR-820 is easier to service and find replacement parts for, but this should be verified with someone like Merrylander.

I have one of each and I would say that I prefer the CR-820 over the CR-640 in every way. It is much better looking, it sounds better to my ears, and has the additional third tone control that I like as well. The 820 would definitely be an improvement over the 640. Good luck!