I am getting a pair of used svs 20-39cs subs and I am wondering if I need to buy extra amp to power these guy. I have the Denon 3801 receiver and Rotel 985Mk2 amp. The front main speakers and 2 rears are powered by the Rotel and the other rear channels are powered by the 3801. I am thinking of running all the rear channels through the 3801 and the 2 free channels from the Rotel will power the subs. Is this new set up ok? What do you guys think?