So I picked up this soundstream touch screen headunit and have wired it up properly bar one thing, the RCA leads. I have a monoblock which has rca leads running to my 4channel amp, which then has both channels running up to the front of the car which then went into a cable which looks like this >-- so that I could turn two channels and run them both off my old headunit which only had 1RCA preout. This new amp has different coloured cables, two of which are for Line R, Line L. Then there is Line LR, LL, RR and RL. As well as Sub L and Sub R. 8 possible plugs, when I only have 4 coming from my 4chan amp, 6 if I ran cables straight from my monoblock, but I would like to keep it running off the other amp. How on earth do I do this? I've tried every possible combination and it just wont work at all. Any help would be GREATLY appreciated.