Hey Ken, I'll do my best to explain this. I have an NAD T762 which has 7.1 pre-out and 7.1 main-in. They use jumpers to bridge to the channels together. I'm not too sure why they used this design (maybe for those that just want to use the amp section), but it's perfect for the ICBM. It's more like using the ICBM with seperates and it allows you to use the ICBM with all different sources. In my case that's my cd player (NAD C541), universal (Denon 2200), PC, TV, and, iPod.