I have a Rockford Fosgate RFX 8310. I know it is old, at least 12 yrs, and I do not want to but a new cd player. I want to connect my mp3 player to it and play it through my auxiliary. It does not have RCA inputs, only output. It does have a place for a big auxiliary cable for a cd changer. Is there a product that will plug into that auxiliary and then into my mp3, or go from that auxiliary to RCA cables, because I bought the RCA cable adapter kit from walmart, I just have no RCA inputs.