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Passive/Active switch on Bartolini NTMB preamp

Discussion in 'Luthier's Corner' started by wilser, Feb 17, 2005.

  1. Hello,
    I'm wiring a bartolini 3 band preamp harness for active/passive switching via a DPDT switch. I've wired according to the instructions and it's working ok. But I have a question: When working in passive mode, does the preamp drain from the battery? or is it 'off'?

    Here's the diagram I followed:
  2. I'm take a bit of a stab here and say the battery will still be being drained. There's nothing there that indicates that the battery has been disconnected, only that the preamp has been taken out of the signal chain.

    Josh D
  3. Thanks, that's kind of what I figured. And I should have expanded my question to the intended one:

    Does anybody know how to modify this wiring so that the preamp will be OFF (not use the battery) when in passive mode?
  4. FBB Custom

    FBB Custom TalkBass Pro Commercial User

    Jan 26, 2002
    Owner: FBB Bass Works
    You have to break the 9/18V circuit at the same time that you bypass the circuit. No real way to do it with a DPDT, but it should be pretty easy if you use a 4PDT switch. You could even wire in an LED with the 4PDT switch if I'm not mistaken. I wonder why no one really does this. Sounds like something I will have to try.

    Exercises like this are a good way to test if you really are grasping what's going on inside the wiring.