It doesnt surprise that you enjoyed listening to the AU-517 so much. AU-717, 517... is an outstanding Line and a great circuit design by Sansui Engineers. The 9090DB is a great receiver. Choosing between an AU amp and 9090 is a tough choice. Thats why I own both an AU-717 and 9090DB and have no intentions of ever parting with either. This very topic actually did just come up in an email between myself and an online friend who happens to be very knowledgeable on such matters pertaining to Sansui. In his judgement, the AU-717 is the superior amp to the 9090, more sophisticated circuitry resulting in better specs (slew rate, etc..). That seems logical to me- that more attention can be given to these parameters in an integrated amp than in a receiver.