What connection would I use? I think I would use the Marantz's front channel pre-outs into the pass thru inputs on my 2-channel integrated amp. The inputs are not labeled but I can program them to be pass-thru.
Am I missing something? I know other AC members are using their 2-channel systems as part of their HT.
I think you could use any AVR with Pre-out jacks. One would feed the Left and Right pre-outs of the AVR into one of the unused inputs on your integrated amplifier.
Regarding your other question, the two channel manufacturers have responded to the desire of folks wanting to have their two channel music system do double duty as part of a home theater setup by building two channel preamplifiers and integrated amplifiers with a Home Theater bypass function. The Home Theater bypass function is a dedicated input that bypasses the gain circuitry in the device to feed the Left and Right signals from the AVR directly to the two channel power amplifier. In the case of an integrated amplifier the power amplifier is within the unit. Look at the picture of the back of this Parasound preamplifier for further explanation. http://www.parasound.com/p6.php
The AVR has the ability to set the gain of each channel independently, or you can run the calibration software that is built into the AVR and do it automatically. You do this once when you set everything up the first time.
I will speculate that this is how many of the AC'ers do it. They have equipment with Home Theater bypass inputs.
BTW Some AVRs also have built in dialog enhancement capabilities. That's a different discussion for another time.