If you’re looking at a new receiver, all you need to do is make sure that the unit offers Dolby Pro Logic II (or IIx if its a 7.1 receiver), or DTS Neo surround capabilities. These features are specifically for listening to non digital sources and recreate a 5.1 – 7.1 experience for VHS, Cable, Satellite, whatever you connect to it. If the source is in Dolby Pro-Logic then the sound will be very good in Pro-Logic II mode. If its just a stereo signal it will still sound pretty good and give you more of an experience than a standard Dolby Pro Logic receiver, because more signal is sent to the rear speakers.
I Hope this helps.