I am currently working on a bass with a bartolini stingray replacement pickup and a pre-wired preamp. Its the Bartolini 2.3/AP. It has a bass, treble, and push/pull(active/passive) volume. I have it wired up just as the diagram says and connected to a 9 volt battery. The sound and tone is great when I pull the volume knob out for passive mode, but when I push it in for active mode i get no sound at all. I have tried every different combination of wiring on the output jack but still have nothing. I don't need to hook up a second 9 volt do I? Any help would be greatly appreciated. Thanks!