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Redoing Hohner B2A wiring, active EMGs, passive electronics

Discussion in 'Pickups & Electronics [BG]' started by Stealth, Apr 21, 2010.

  1. Stealth


    Feb 5, 2008
    Zagreb, Croatia
    Alright, the Hohner B2A I bought second-hand a few weeks back proved its worth as far as the tone's concerned - the EMB-HBs really have a monstrous tone. Now it's time to fix the wiring inside for a few reasons:

    • The wiring is poorly marked - five out of ten wires are yellow, and threy don't designate the ground.
    • The pickups are active, thus necessitating a stereo jack.
    • The old stereo jack was crackling because it didn't grip the output cable firmly enough - the cable would pop out under its own weight.
    • I want to exchange the old three-way switch (neck/series/bridge) with a two-way (series/parallel) complete with the "individual series volumes" mod, pickup loading be damned.
    • The red LED has to go - I want a green one. :D

    Since the bass sounds good as it is, I want to keep as much of the original electronics specs as possible.
    • The two vol pots are 25K, linear taper - easy to source, makes sense since it's standard value for active pickups.
    • The DPDT on-on won't be a bother, either, neither will the LED be.
    • I've already found a decent stereo replacement jack with a chassis mount, as that's the type that fit inside the electronics cavity.

    However - the tone pot is a 25K audio pot with an unknown capacitor on it. I haven't a multimeter to test it with, so I hjve no idea what it is aside from a mysterious label 1K10 (which would suggest a 1100nF, or a 1.1 nF capacitor). I haven't seen any 25K audio pots around, and the 1.1 nF caps are also confusing as they're usually either 1.0 nF or 1.2 nF.

    The maths works out odd, too, as the RC filter should give a cutoff at about 5.7 kHz - but at the fully closed position. Fully open just goes on and on beyond audio range...

    Can someone shed a light on the proper wiring? Or, rather, the proper tone pot and cap values for an active pickup configuration?
  2. Stealth


    Feb 5, 2008
    Zagreb, Croatia
    Thursday morning bump.
  3. Stealth


    Feb 5, 2008
    Zagreb, Croatia
    Thanks for the link, but it doesn't help - there is no more active electronics board to speak of, it was bought with active pickups and passive V/V/T controls. What confuses me are the right values and tapers for the pots.
  4. ex-tension


    Jun 11, 2009
    Active pickups can't be wired in series. You have to connect ground wires of both pickup to the battery so, it's parallel only.

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