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Active to passive blend pot

Discussion in 'Pickups & Electronics [BG]' started by TomasNI, Dec 21, 2014.

  1. Dec 21, 2014 #1
    TomasNI

    TomasNI

    Nov 27, 2014
    Bangor NI
    Hello,

    Anyone could tell me please can I replace blend pot 25k to 250k in active bass to get it working in passive mode?

    It has G&B 3 band Preamp, 500k Volume pot and 3x 25k Tone Pots.

    Im planning change Blend Pot to 250k as mentioned also change one of the tone pot to stacked 250k to make it work in passive mode will this work?

    Of course there will be active/passive switch added too.

    Thanks in Advance!

    Cheers,
    Tomas
     
  2. Dec 21, 2014 #2
    mmbongo

    mmbongo I have too many basses. Supporting Member

    Aug 5, 2009
    Upstate, South Carolina
    What exactly are you trying to do here? Fix the passive mode on your preamp? If that does not work, you've got problems elsewhere...like in the switch.

    If you replace the pots like you said, you'll have to remove the preamp entirely.
     
  3. Dec 21, 2014 #3
    line6man

    line6man

    Jun 20, 2008
    Close to Los Angeles, CA
    Do you have passive pickups?
     
  4. Dec 22, 2014 #4
    TomasNI

    TomasNI

    Nov 27, 2014
    Bangor NI
    Hello,

    My apologies, I have checked the pot one more time and it`s 250k so can easily do the mod now. Im going to buy dual 50k and dual 500k and make my dual 50k/500k tone pot.

    Yes these are passive humbuckers (ESP B-205 Fretless Bass)
    Im going to use this advice as well:
    http://www.talkbass.com/threads/bartolini-active-passive-tone-control.703202/#post-9869680

    Will let You know when finish as I guess few could do the same mode. You never know when the battery will go flat.... ;)

    Thanks!!

    Tomas
     
    Last edited: Dec 22, 2014
  5. Dec 27, 2014 #5
    TomasNI

    TomasNI

    Nov 27, 2014
    Bangor NI
    Hi,

    Here is my version of the mod as in original wiring the tone pot do not work in Jazz Bass with single coils:

    switch-ok.gif
     
  6. Dec 27, 2014 #6
    line6man

    line6man

    Jun 20, 2008
    Close to Los Angeles, CA
    That's a terrible way to wire it. The volume pot needs to go before the preamp, because there is usually a drastic change in signal impedance when switching between modes. If a high value pot is used with the "active" signal, it will behave like an on/off switch, and if a low value pot is used with the "passive" signal, it will load the pickups and reduce output.
     
  7. Dec 28, 2014 #7
    TomasNI

    TomasNI

    Nov 27, 2014
    Bangor NI