http://www.emgpickups.com/content/wi...G-BQseries.pdf
That's the instruction sheet. Just look at the two setups and you can figure it out...
It's kind of a long-story-short explanation, but basically, the SYSTEM includes the pan pot and volume wired to it already.
The CONTROL is the same as the SYSTEM, but without the pan/volume. Those are just mounted to a board for convenience, I guess.
On any preamp, you have an INPUT, OUTPUT, and GROUND...
The BQC has a white INPUT, black GROUND, and green OUTPUT.
1) If you have a couple volume pots or a pan pot, connect the WHITE from the BQC to the OUTPUT of that existing setup.
2) Make sure you ground everything properly (BLACK wires connected to the bridge ground).
3) GREEN goes to the tip of the output.
4) Connect all RED wires together and make sure they go to the red wire of the battery clip.
I've done this a few times. Worked fine for me!