I am dealing with the same dillemma. If you have a processor loop on your two channel preamp, it's easy. If you don't...I have done some research on it, and here's what I came up with:
Run the Left & Right channels of the HT Processor into an input on your two ch preamp.
When using the "home theater mode" select that input on your two ch preamp, and figure out with a spl meter what volume setting on your two channel equals the "no gain, no attenuation" setting (you will need to do this, because you will have two volume controls active: the one in the processor and the one in the two ch preamp, in an overlaping config.)
Mark the spot on your volume pot of the two ch pre with crayon or something soft as to not damage the finish.
You will have to have the volume of your 2 ch at that exact spot every time you watch a movie, and you will be using the processor's volume control for 5 ch gain.
When you want to listen to stereo, you shut off the processor, and your two ch preamp is running direct into your amp.
Also run all your 2 ch analog signals thru the two channel preamp, and not thru the HT precessor.
I am getting much better sound from my stereo preamp than my HT preamp, so I use the two ch for all my critical listening and only turn on the HT pre when wathing a movie.
Run the Left & Right channels of the HT Processor into an input on your two ch preamp.
When using the "home theater mode" select that input on your two ch preamp, and figure out with a spl meter what volume setting on your two channel equals the "no gain, no attenuation" setting (you will need to do this, because you will have two volume controls active: the one in the processor and the one in the two ch preamp, in an overlaping config.)
Mark the spot on your volume pot of the two ch pre with crayon or something soft as to not damage the finish.
You will have to have the volume of your 2 ch at that exact spot every time you watch a movie, and you will be using the processor's volume control for 5 ch gain.
When you want to listen to stereo, you shut off the processor, and your two ch preamp is running direct into your amp.
Also run all your 2 ch analog signals thru the two channel preamp, and not thru the HT precessor.
I am getting much better sound from my stereo preamp than my HT preamp, so I use the two ch for all my critical listening and only turn on the HT pre when wathing a movie.