The Sansui 881 was the top of the line recceiver 1975. It was followed by the 9090. The similarities are apparent when you look at the electronic layout. I prefer the 881 over the 9090. I really can’t pinpoint why. It really doesn’t sound better, there is just something about. Very nice amp. I gave this one a new wood cover and replaced all the electrolytic capacitors, the speaker relay and the fuse resistors.