It really depends on the module you are using and whether you are using 2 zone head and rim or just a single zone. Like for instance Roland wires there head piezo in a reverse polarity. So the the ceramic disc lead on the piezo would go to the sleeve on the jack while the brass bar metal portion lead would go to the tip of the jack. On the rim piezo you would take the ceramic lead wire and wire it to the ring and the brass bare metal wire and solder it to the sleeve. While with Alesis Modules the polarity is not reversed for the head piezo. The ceramic lead wire for the head piezo would go to the tip. The ceramic lead wire for the rim piezo would go to the ring, and both the brass bare metal wires from both piezos would go to the sleeve.