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Sorry, another Jazz series/parallel mod topic...

Discussion in 'Pickups & Electronics [BG]' started by Farside, Jan 21, 2004.

  1. Farside


    Dec 10, 2003
    Now before you say anything, yes I have done a search but out of all the topics on the two pages I got from searching for 'series mod' all i got were confusing wiring diagrams, topics that ended up talking about something else, topics with dead links or topics telling someone to use the search feature. So here I am asking one main question, what exactly is the mod and how do I do it? I have a Squier standard Jazz bass and minimal soldering experience, to be honest I am worried that if i attempt the mod I will botch it as I have only had the bass a few months and have never needed to open it up. I understand that if i do the mod i will have to replace one of my tone knobs with a push/pull switch; does this mean I will lose control of one of my pickup volumes permanently or is this only so when in series mode? Is there a way of accomplishing this mod without replacing a tone knob? What I really need is simple step by step instructions for this mod that a newbie like me with very limited electronics experience could understand, I'm sure it could also help other people in the future.
  2. David Wilson

    David Wilson Administrator Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    Well, it doesn't have to be the tone knob. It could be the volume knob. Or you could drill a DPDT switch through the pickguard. But a switch needs to be there somewhere so you can move between series/parallel.

    The mod is basically making your two pickups operate as one i.e. the ground of the neck pickup is joined to the hot of the bridge pickup. You'll get a higher output, and a more mid heavy sound.

    When in series, the bridge volume will be inoperative as the neck hot signal isn't going into the bridge volume pot. When in regular parallel mode, both vol pots will work as normal.

    It's really very simple, it'd be hard to mess it up but I can understand your reticence if this is your first mod work.

    If you can reference the wiring diagram you're looking at, let us know what is confusing you.
  3. Farside


    Dec 10, 2003
    Thanks for the reply, I have opened up my bass and made a crude diagram of the wiring which I have attatched. As I understand the black wire is the grounding (?) wire and the red wire is the 'hot' wire.

    Would I be able to make the bridge volume knob the switcher between series and parallel because I don't know where I will be able to buy a switch (no radioshacks here in England) and would rather leave the original hardware in. If this is possible what wiring would I need to add/take away and what controls would I have in parallel 'mode'?
    Thanks again for your help.
  4. David Wilson

    David Wilson Administrator Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    ok, lots of questions....

    your diagram:
    black is the ground wire, yellow is the 'hot' pickup signal wire.

    Your hot signal enters the pot in the middle lug. A varying amount of that is bled off to ground (the rightmost lug with black wire grounded to back of vol pot) - that's your volume control working. The leftmost lug has the output with that portion not going to ground (i.e. when volume is full, none of the signal is going to ground)

    You can make either the neck or bridge vol pots your switch. I'm not sure where you could get a 250K audio taper pot (for volume) with attached DPDT (double pole, double throw) switch. Maplin Electronics is probably a good place to try. You're looking for something like this:
    http://www.stewmac.com/shop/Electro...s:_Control_pots_and_knobs/3/Control_Pots.html - I'm assuming you have stock single coil pickups so you'll want a 250K pot. Ignore what it says on that page about active pickups, that'd really only be relevant for a 25K pot or using it with a preamp to have active/passive bypass.

    Do you have a particular reason for wanting the bridge vol as the switch, as opposed to the neck vol? It doesn't make any real difference, just wondering.

    When in parallel mode, as I said, your controls will operate totally as normal. When the switch is pulled up, you're in series mode and the bridge volume pot will do nothing (regardless of whether you have neck or bridge vol pot as the switch) - the neck vol pot will control your overall volume as you now have effectively one dual coil pickup when in series mode.

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