Once you use the AVRs pre-outs to power the speakers (your M80s) only the amp's (your HK 990) power will be used, the AVR won't do anything but control the volume and act as the processor ... EZPZ

I use a Rotel RB-1080 to power my M80s with a 85 watt per channel HK AVR3600 to do the processing.

Rick
Our Room

smile