i use the preouts on a Marantz sr5005;

the Marantz directly drives the rear surrounds;
the 2 QSC power amps are used for the front and side surrounds.
(i don't use a front center channel).

check the links in my signature...

See: http://www.blu-ray.com/community/gallery.php?member=Gelli
or: Axiom Gallery