My dad has a Bose lifestyle 2400 and his receiver crapped out. He then bought a pioneer vsx-515-k, hooked everything up fine except for the sub. It has a red & white rca and what looks to be a headphone jack coming out of the wire that plugs into the sub. I've tried The rca's split to one and into the preout but it didn't work as well as an adapter to change the headphone jack to an rca and into the preout . Can anybody HELP ME?