I have this really annoying problem with my Bartolini's. My bass is an Ibanez SR905. They're active ones, right, and they keep draining battery power even when I'm not plugged in. For example, I put in a fresh battery and maybe not play for a couple of days. When I plug it in it has either really low power or the battery is completely dead. It's obviously a cable-problem but I haven't been able to fix it. Even let some dudes at the ESP office in Finland take a look at it and replace some of the wiring in there. Any tips? Or should I maybe consider getting brand new pickups? (Might be the actual mic's themselves that are screwed, I don't know) This is really frustrating when you are on tour...
It sounds like the TRS output jack is messed up. It should disconnect the battery when the plug is removed. It would be very easy to see if this is the case with a multimeter. It's very unlikely the problem is actually with the pickups.
Bartolini MKII aren't active pickups, it's the preamp that's active. I second Crater's comment. The jack is a mechanical switch; when there's nothing plugged into it the battery ground is lifted and there's no way for the battery to drain. There is either a short on the jack wiring or the jack is maybe shorted against some shielding?
