Hey all, I picked up a set of 40CSX pickups to swap out for a 40P and 40J. Rather than us the volume and tone pots they come with, I just plugged them into the BTS pre already installed on the bass. The pickups sound good, but they seem to lack power/volume. Do you need to use the X series pickups with the tone pot? Can you use them with the BTS pre? Any idea why they seem weak?