hooking up HT amp

Hi all,

I am going to hook up my old Sunfire Cinema Grand to pump up my system some, the only thing is I have a "pre-amp" mode which shuts off all the amps in my Yammie RX-Z7 and was hoping to use the one back surround channel to complete my 6-channel hook-up as my Sunfire Is only 5 channels which would be hooked up to my def-tech 7002 mains, clr-2500 ceneter and Infinity entra rears. I have the Infinity rear center as well.. If i turn off "pre-amp mode" in the receiver the amps are all "hot" but can i still not use the speaker taps for the mains, center and rears and just use the rear center with the Yamaha and the sunfire cinema hooked to the rest of the pre-outs.. the only thing i can think of is the Yamaha might run a little hotter .. but i am not sure if this is still OK to do.. I have seed some people do this on other message boards saying there really isn't much difference between "pre-amp" mode or just hooking up with the pre-outs active cause apprently there is a "muting" circuit that cuts off those channles that you aren't using as soon as something is connected to that particular pre-out as people seem to be hooking up just therere old audiophile two-channels to the mains pre-outs and letting the Yammie do the rest... If anyone has any advice or help .. I would appreciate it... (i wonder of pre-amp mode is more for different audio zones like zone 2 3 etc) thanks for any help!