Hi Bernie -
I don't think the 990 converts analog signals to digital; it just passes them through, in both stereo and bypass modes. The latter mode means no tone control is available. I imagine Gonk will correct me if I am wrong! I bought mine over any other brand except the Sherwood - which as you probably know costs $400 more - because it has a phono input, and have been very pleased with its performance on phono and tape (both cassette and open reel - way better than the Adcom TPA500 I had before. Others can discuss the 990's surround and subwoofer capabilities since at present I'm running pure 2-channel stereo and thoroughly enjoying it.

Enjoy,

Paul Nay