Mjcmt, Let me save you here, People seem to be missing the real issue, the OPPO players Digital processor built in does not have the capability to mix the Center Voice on a DVD disc to the front Left and right, Yes an old 4 channel receiver as long as it has the 4 separate mono channel inputs could in fact allow you to get away with hearing the front L & R , rear L & R just fine, however you will have no Dialog, because you will need a fifth channel in this case to output the Center channel jack of the oppo to another amp and fifth speaker..
Only way around this is to use what is mentioned above, A newer Pro logic type receiver from about probably 1992 and up that has the capability to take a connection from the digital outs either Toslink or Coax from the oppo player and decode the 5.1 signal of a DVD down to "Phantom mode" which yes then eliminates the Center speaker all together and runs voice thru the L & R while still retaining the Rear Speaker surround effect channels.
I mean unless you use both the L & R channels on the OPPO and simply set the processor inside the Oppo for Stereo out Mix not 5.1 Mix you can get 4 Stereo channels, but of course this will not be true surround sound or Have the Bullets speeding between the Two rear speakers it will just be all information sent to all 4 channels. So in a nutshell no you can't use old Quadrophonic receivers just for the amps and get true surround sound without a processor capable of running a 4 Channel phantom mode, and I doubt any DVD players have ever been built with this function in it.
Only way around this is to use what is mentioned above, A newer Pro logic type receiver from about probably 1992 and up that has the capability to take a connection from the digital outs either Toslink or Coax from the oppo player and decode the 5.1 signal of a DVD down to "Phantom mode" which yes then eliminates the Center speaker all together and runs voice thru the L & R while still retaining the Rear Speaker surround effect channels.
I mean unless you use both the L & R channels on the OPPO and simply set the processor inside the Oppo for Stereo out Mix not 5.1 Mix you can get 4 Stereo channels, but of course this will not be true surround sound or Have the Bullets speeding between the Two rear speakers it will just be all information sent to all 4 channels. So in a nutshell no you can't use old Quadrophonic receivers just for the amps and get true surround sound without a processor capable of running a 4 Channel phantom mode, and I doubt any DVD players have ever been built with this function in it.