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Bypassing preamp switch?

Discussion in 'Pickups & Electronics [BG]' started by zanthrax, Apr 11, 2002.


  1. Hi!

    I want to modify my Yamaha BBG4II a little. Since it's an active instrument it sucks out the juice in the battery if you leave the cable plugged in (just pointing out the obvius)... I want to be able to leave the cable plugged in and just "turn off" the battery. Well that part is very easy, just by a push-pull pott and "break the circut". But... I've been fiddeling with the thought of giving the bass an passive mode. Is anyone familiar with doing this? What will I have to do to make it work? Buy another volumepot? Another blendpot? Both??? If I don't have to buy another volumepot because of the way the preamp is built will it work with my current (it has a strange "number", somewhere between 20k and 25k)?

    Should I try to find a schematic (or figure it out), would that be sufficient information? (I have a strong feeling that this isn't sufficient information...)

    And finaly...
    I'm currently looking at buying a MEC pot. Opinions? Do you think there are other brands offering what I want? EMG? Bartolini? Other? Since I live in Sweden there's no such thing as Radioshack either... =(
     
  2. It seems like I've asked a question that nobody can answer... On the other hand its very likely that I'm a bit too impatient...

    On my quest for knowledge I've figured out the basics of the preamp. I've tried to make some kind of schematic in Paint (BEWARE I am not good at that)...

    Hopefully someone will be able to understand this "drawing"... Here goes:
    [​IMG]
    I've noticed that it is not entirely correct. The volumes connections should be were the are but the numbers should switch places. 1234 should be 3214. I think the rest is correct. If someone is wondering the one with 4 connections is the volume and the one with 6 is the blendpot. The "?" means that I don't know were they go... They disapear through the same hole as the wires for the pickups. Could it be the dummcoil in my pickups? Other suggestions?

    I have an theory how to make a passive mode. I insert a DPDT between the blendpot and the "basscircut" and wire it so that it goes through the preamp in one mode and goes directly to the volumepot in the other. Would this work?