John, if I have an "amp box", I don't know where it is...I would assume it would be up/overhead somewhere in the front where the video signal routing box, VCR, and Antenna power supply are located but there is nothing there. Nothing on the other side where the satellite TV box is either. I figure if I have a box, it must be somewhere that is accessible. That is what led me to believe it was a passive system. The system appears to have 4 small speakers hanging down over the sofa and chair area up front and a couple of larger speakers (6x9s), one beside the driver and one under the refrigerator.
Michael, to answer your question I had to go play with the old TV which luckily, I hadn't tossed yet. The coach speaker system plugged into a plain mini-jack receptacle on the rear of the TV with no "earphone" label. What I discovered, while testing though was that plugging a mini jack into this receptacle did NOT cut off the TV speaker so I'm thinking that the mini jack receptacle was wired parallel to the TV speaker and had benefit of the TV amplifier to drive the sound system. That reinforces my thinking that the sound system is passive.
The one odd thing is that the mini-jack which plugs into the TV has been "spliced" into the wire going to the sound system. To me, this doesn't look like "factory work" and gives me cause to wonder if, at some time, there was an amplifier and it failed and has been removed. I'll do some more detective work, maybe look behind the larger speakers to see if there is any localized amplification. I think I need a small 2 channel amp to put between the TV and the sound system, at least on the TV input. Apparently the radio and CD player have enough power to drive the passive system. Thanks for the help guys....I'll figure it out eventually.