You can use 2, 3, or 5 channel amps with your Marantz. If you prefer to use just a two channel, simply plug the amp into your receiver's L/R main pre-outs and use the on-board amps for the center and surrounds. Make sure you recalibrate your system after plugging in the Rotel to compensate for any differences in gain. My guess is you'll hear a noticeable difference in your two channel music, I sure did.

Hope this helps.