Great thread, just discovered it. Spark’s solution solves the exact problem I’m facing.

Now I want to buy a new HU (3 sets of pre-amp outs), and I want to give the installer the exactly correct instructions, leaving nothing to chance or interpretation.

Spark, could you or one of the other gurus here correct me where I got it wrong?

Instructions for installer
1. At the amp: about 2-3 inches from the amp, cut the wires at pins 6 & 7, and at pins 1 & 2. (Cut on the amp side of the existing wire splice as installed stock)
2. Splice new speaker wire at each cut, and run the new speaker wires up to the (new) HU
3. At the HU: connect the new speaker wires to the RCA jacks for “Front” pre-amp output
4. At the HU: connect the existing speaker wires (pins 9 & 10, and pins 8 & 3) to the RCA jacks for “Subwoofer” pre-amp output.
5. At the HU: ignore the pre-amp outs for “Rear” output

That look right? Anything here that will confuse a Best Buy installer?

Not having *any* experience at this, an ignorant question: how do the wires from a given pair of pins at the amp, become a single RCA plug on the other end? For example, the wires from pins 8 & 3 need to terminate at the HU in a single RCA plug that jacks into “Left Subwoofer” pre-amp out. How does 2 become 1?