Hard to say. Most receivers power ratings are based on 1 or 2 channels operating at the same time. It is likely you are not getting a true 100 wpc from your center. That said the 2200 is a 200 wpc amp but that only gets you a theoretical 3 db increase in spl compared to the Marantz. The 602 s3 are not too hard to drive so I would expect something else is masking your sound. Could it be the room or maybe some dynamic gizmo turned on in the receiver. Try moving your speakers around some ad see if that helps and go through your menus to set that part good.