You will need a little accessory, the Mag to Pin-7 Harness to connect the mags to the Hexpander. (you do not need this if you are also installing the Acousti-Phonic; it delivers the mag signal to the Hexpander) Solder the green wire on the Mag to Pin-7 Harness to the tip lug your 1/4" jack, the same point where your mag wire comes from the pots. Note that in Hexpander-only installations, the acoustic signal on pin-7 is the raw sound of the piezos, and is not equalized to compensate for the crystal's characteristics. The Acousti-Phonic provides this option, as well as the ability to blend mag and EQ'd piezo.