ummmm...the more amps it'll need to provide the voltage, not necessarily more watts, but regardless it may cause an amp that's testicularly challenged to whimper.
if you really want EX/ES decoding, you can do it with your current receiver. Simply feed the l&r surrounds into the l&r inputs of a Pro-Logic decoder. Then feed the CENTER-CHANNEL out of the decoder into your back-channel amplifier. The l&r out of the decoder go to the l&r surround amps.
take 2 dvd's and call me in the morning! Actually, I've seen pro-logic decoders selling for $15 at local hi-fi shops, and you'd have to buy the wires for a new receiver, anyway.
Unless its state " XX.Power for all channel driven simultaneously into 8 ohms at full bandwidth (20Hz to 20KHz) with THD < 0.1%. These numbers are a starting point in judging the quality of the power supply and amp section. I was suprised when my Denon 4802 ran out of headroom while I was "aggressively" listening to the latest Steely Dan - Everything Must Go. I am now considering the Outlaw 200W monoblocks for the Front L,C,R speakers and letting the Denon's internal amp power just the rears. The amp section seems to be a common Achilles Heel found in many surround receiver units. Whether it is for reasons of cost effectiveness, or enclosure restrictions, it always seems like this section gets the short end of the R&D stick. :frowning:
I'd recommend maybe getting a good monoblock or brigeable amp for the center channel as this is the most used channel and therefore the most burden should be relived.