I think any sort of switcher will degrade signal purity and sound quality since it has to go through another circuitry.
@ghulamr
You will need to get an analog stereo preamp that has HT bypass input. And you can run your Benchmark DAC1 directly to the stereo analog preamp, and run the front LR channels pre-outs of your Marantz HT processor to the HT bypass input on the stereo analog preamp thus bypassing the volume control on the stereo preamp when using your Marantz HT processor for surround sound movie playbacks. And simply connect the stereo analog preamp to your Simaudio power amp for your front LR speakers.
@ghulamr
You will need to get an analog stereo preamp that has HT bypass input. And you can run your Benchmark DAC1 directly to the stereo analog preamp, and run the front LR channels pre-outs of your Marantz HT processor to the HT bypass input on the stereo analog preamp thus bypassing the volume control on the stereo preamp when using your Marantz HT processor for surround sound movie playbacks. And simply connect the stereo analog preamp to your Simaudio power amp for your front LR speakers.