I am setting mine up that way without a secondary amp..the speaker outputs for 4 rear height speakers don't require having a second amp from what I understand and read while going through the set up process. So the 7-2-4 set up should work without requiring more equipment. One thing that you can do with this reciever is turn of the internal amplifier to speaker channels you are not using..being each channel has it's own internal amp as part of the reciever design. I hope this info helps....