How do I listen to stereo audio?

How can I have the best of both worlds. I want to convert my audio system to home theater via the Bryston 9b. I want to be able to keep my Levinson preamp and use that for listening to stereo, but then use a surround processor for theater. How can I do this, do some good processors have some sort of passive pass through. Thanks. Matt
Here's a post from audioasylum that should help you out: Posted by Michael on November 05, 1999 at 07:45:21: In Reply to: Re: Need Help:How can I connect a pre to Theta Casanova posted by Joly on November 04, 1999 at 22:11:12: Joly, Are you attempting to add a dedicated 2 channel preamp where you would use the that unit for music and the CasaNova for HT? If that is the case, then it is not really not that hard to accomplish. You can do this in several different ways. One of the easiest ways is to purchase a 2 channel preamp that has a unity gain feature. A unity gain is essentially a pass through where the incoming signal is passed directly through without being affected by the gain of the preamp. Take the front L&R preamp outputs, from the CasaNova, and connect them to an input on the 2 channel preamp. Connect the preamp L&R outputs, from the 2 channel preamp, to your amp as usual. If the 2 channel preamp does not have a unity gain feature, then you could use the tape monitor capability and if all else fails, simply use any available input on the 2 channel preamp. In the last case, you will have to set the 2 channel preamp volume knob to a known position, which should be as high as possible, whenever you want to use the CasaNova, for HT. Also, keep in mind to calibrate the front L&R speaker levels, through the CasaNova, noting the volume knob position on the 2 channel preamp. I hope this helps.
Oh, also some prepros do have analog passthrough. But their digital bypass will not give you the best analog stereo possible. You can use what you have and follow the tape monitor method in the above post.
I don't know if your levinson has a 'processor input'. My adcom does. With this scenario, you would go Home Theater Receiver variable outs-> adcom pream processor input -> amp -> speakers. You would control the volume with your home theater volume control. You would also have normal CD Player->Adcom preamp->amp->speaker combinations where the volume would be controlled by the preamp.
John, that's essentially a unity gain as I described above. As far as I know, no Levinson pre has it.
I suggest you sell your Levinson pre and purchase a Proceed AVP. Its a HT pre/processor that contains many of the best Levinson components (such as their best multibit DACS in the right and left channels). I'm very happy with it.