Aloha Mark, but your question almost fell through the cracks. I gather that you want to use all four surrounds in your 7.1 setup to duplicate the sound in the 4th and 5th channels of a SACD. I'm not sure that's such a good idea since if the SACD surround channels contain discrete info to precisely locate a musician or other sound(rather than just general ambience, which classical SACDs typically put into those channels)it may confuse the location to have the back surrounds also playing the same thing(some prefer direct radiating surround speakers for SACD music to get a little more precise localization).
Be that as it may, if you want to try it, you'd just get two Y-connectors from the usual sources. You could plug one into each analog surround output on the Oppo and then run two coaxial cables from each so that all four multiple analog surround inputs on the 990 were connected. Then, when you selected the 7.1 multiple analog inputs on the 990 it would output it(with the usual coaxial cables)to all four surround channels on your amplifier(if you still have the 7125 you have all the amplification that you need).
