I have (used but in original boxes) a M-72 2ch/4ch power amplifier, C-91 pre amplicateur stereo, Sp 910 dolby prologic sound field processor and F-93 AM/FM digital synthesizer tuner. I'm a student (elementary edudation) and haven't a clue what this might be worth or what I need to put with it to make a complete system. I think it was purchased sometime in the 90's but I'm not really sure. Any help would be greatly appreciated.