I installed a set of Gibson Burstbucker Pros into a friends schecter, single volume, single tone w/push-pull coil tap. The pickups sound fine on their own. When both are engaged, there's a definite volume loss. I tried switching the bridge pickup hot and ground wires and that sounded terrible. Both pickups are 4 conductor with the white and green soldered together for the coil split, red for hot, and black for ground. Thoughts or suggestions?