Ok I finished my first two basses Bart pre upgrade. They sound amazing. and now I am on the third which has EMG Pups and an Aguilar OBP-1 which I am taking out(taken out). I wired the pups to the pre but the volume is really low. Are all EMG's other than the Hz series active? Would this be the problem of why the volume is so low, or would they even work if they were active and not directly connected to a battery. I know barts are made for passive pickups, but I don't know if the EMG's are active. They have a red + wire and a white with a shielding or bare wire around it.