http://www.whathifi.com/news/how-to-add-hi-fi-amplifier-to-your-home-cinema-system
Stereo amplifier to home theater amplifier pre outs
http://www.hifihunter.com/articles/improving-stereo-performance-surround-sound-setup-part-1/
http://www.hifihunter.com/articles/improving-stereo-performance-surround-sound-setup-part-2/
http://hometheaterreview.com/stereo-preamplifier-reviews/