Anthem does not have a PA5 amp. It has a P5 and an A5 amplifier. In either case, I would probably say this would be a significant upgrade from the Onkyo receiver because you are putting so much more into an amplifier power supply with more amp output transistors per channel. I'm sure the processing and D/A of the Anthem AVM50 is very nice as well. You can take advantage of the balanced outputs of the AVM50.