It's not just a power issue, it's a noise floor issue. I don't like the hashy sonic mess and compression you get when you have low-level analog and digital decoding components sharing a chassis with all the vibration (60 Hz) and heat you get with what should be a high current 7-channel amp.
I have my power amps on a separate shelf from my pre/pro. True, you can get 150-to-190 wpc A/V receivers, but not only are you adding all that jazz to a low signal chassis, in most cases they compromise the power supply to get everything to fit. And that's another source of compression you get with a receiver.
Look at the specs and test reports for most A/V receivers. They rate the power with one channel driven, and often with a 1KHz test tone (no bandwidth) at 1% distortion. An A/V receiver tested at 90 wpc under those circumstances only puts out about 43 wpc with all channels driven, 20-20KHz, at 0.1% distortion. And I've seen enough Home Theater mag test reports to prove it.
Most A/V receivers rated at 125 wpc will not have anywhere near the balls of a similarly rated separate amp from Adcom, Outlaw, or Parasound, never mind the high-priced spread.
