Need Help Understanding Bart Pickup Wiring

Discussion in 'Pickups & Electronics [BG]' started by Medici, Feb 15, 2020.

  1. I've paired some bartolini p25cbc pickups with a tone monster sbk-3a preamp/eq. As a forward this is a custom bass with no previous electronics. I'm having trouble understanding what to wire into the terminals on the preamp coming from the pickups. It's a 4 conductor pickup with one black, green, red, and white, and the red/white are soldered together from the factory. The preamp simply requires the hot from each pu and the ground to operate. I inquired about this after not gathering what I needed from the given wiring diagram, and this is what the bartolini rep replied with;

    "The P25CBC is a four-conductor cabled (you don't count the bare shield as a conductor) pickup:
    Black is the bridge coil hot out
    White is the bridge coil end
    Red is the neck coil hot out
    Green is the neck coil end.

    If you connect red and white and ground green the black wire is series humbucking
    If you ground red and white and green you have bridge coil single
    If you connect red and black and ground white and green you have parallel humbucking
    If you connect red and black and leave white open you have neck coil single
    If you gound black and make white the hot out you have out of phase coils."

    I'm fairly new to this and I'm sure I'm making this more complicated than it needs to be, but I'm between series/parallel and was wondering which would be the better option for a 5 string fretless. I have full range control including a mid frequency shift. Any and all advice is appreciated.
  2. funkinbottom

    funkinbottom Gold Supporting Member

    Apr 23, 2006
    Northern CA.
    I use the same PU's and personally I just wired mine series. I've have other basses with series/parallel switches but never seem to use the parallel mode. In parallel you do get a little brighter sound, but considerably less output. I'll take more output over a little brightness, thats why I have a preamp.:)
  3. mikecd1


    Mar 3, 2009
    New England
    You can do a push-pull switch to go back and forth between series and parallel and its easy to wire with lots of diagrams out there. It gives a lot of versatility especially if you have two switches and you alternate between pups with one series and the other parallel. I'd think on fretless this might be even more useful.