Help with adding series/parallel switch to my PJ?

Discussion in 'Pickups & Electronics [BG]' started by RiZzBot, Nov 15, 2015.

  1. RiZzBot

    RiZzBot Drunk + bass + broken strap locks = :'( Supporting Member

    Nov 23, 2014
    210, Texas
    I have a "franken" PJ bass that I want to add a series/parallel switch too. I like the idea of getting the mid/volume by running the pickups in series. I see a billion different switches on ebay. I'm assuming that a three way switch is what im looking for here. There are also a lot of different wiring diagrams to choose from. I'd appreciate if someone could link a good wiring diagram for vol/blend/tone with a swicth (if this makes any sense). I kinda like the idea of only one volume knob. I'v already googled and TB searched this, and was bombarded with a ton of ideas. I dont know too much about this mod in particular, so any kind of help would be much appreciated here. Thanks friends.
  2. Series/parallel switching with a blend pot can be accomplished in three ways.

    1. You can use standard series/parallel switching with a DPDT On/On switch. This is the simplest option, but the caveat is that the blend pot is going to behave like a volume pot, when you go into series mode. This is very inconvenient, because the volume is going to drop, if you don't set the blend properly before switching.

    2. By using a 3PDT On/On switch, you can bypass the blend pot when you go into series mode. This method works well, but it is a bit more complicated, and limits your switch choices. If you wanted to use a push/pull pot, you won't be able to do it with this option.

    3. If you opt for an M/N taper blend pot, with an "ungrounded" wiring scheme, then you may use a modified DPDT On/On based switching scheme to bypass the blend pot in series mode. This is very simple, and works well. The downside is that you cannot completely solo either pickup. Most people say that this is not an issue, however, as the volume of one pickup is low enough to be drowned out by the other pickup.
    PawleeP and Torrente Cro like this.
  3. RiZzBot

    RiZzBot Drunk + bass + broken strap locks = :'( Supporting Member

    Nov 23, 2014
    210, Texas
    Would Vol/vol/tone with a switch be more practical? Seems like the blend option comes with a setback of some kind. BTW, this is for a fretless Jazz PJ bass bartolini 8s in the neck and 9J st at the bridge.

  4. VVT just uses the standard series/parallel switching scheme, on a DPDT On/On switch.
  5. RiZzBot

    RiZzBot Drunk + bass + broken strap locks = :'( Supporting Member

    Nov 23, 2014
    210, Texas
    Thanks for your time friend
  6. RiZzBot

    RiZzBot Drunk + bass + broken strap locks = :'( Supporting Member

    Nov 23, 2014
    210, Texas
    You wouldnt have that scheme btw? :D
  7. JazzBass_2VppSP_1T.jpg
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  8. RiZzBot

    RiZzBot Drunk + bass + broken strap locks = :'( Supporting Member

    Nov 23, 2014
    210, Texas

    One more silly question. I see that the schematic is for a push pull pot. Will the wiring be the same for a mini toggle? Once again thanks for all your help friend.
  9. Crater


    Oct 12, 2011
    Dallas, TX area
    Yes, exactly the same.
    RiZzBot likes this.
  10. This is how I'd do it. A push-pull is a neat solution, and it makes sense to remove the blend control in series mode. Also, The "downside", as described is IME, really not one at all. In fact lifting the earth from the blend often opens the tone up a little.
  11. I know this thread has grown a little cold, but I've been searching high and low for a wiring diagram to try this mod on a passive PJ build I'm hoping to start soon. I'm a novice with circuits, so if anyone could help me out I would be very grateful!
  12. 8295530903_ab5566168c_o.png
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  13. Excellent, thank you!

    I have a few more amateur questions...

    Am I correct in assuming that the orange thing at the bottom left is representing the ".05 cap" shown in the Seymour Duncan schematics above? If so, does the value of the pots in the circuit effect the value of "cap" needed?

    I've been reading that with the ungrounded tone scheme you still need to ground the tone pot's casing. How is this accomplished?
  14. PawleeP


    Oct 8, 2012
    East Coast
    anyone have diagram of a PJ with VVT & ser-par on p pup? please!!
  15. bigtone23


    Dec 10, 2014
    Denver, CO
    Use the diagram on post #7 for the VVT + Series/parallel, but add this DPDT switch between the P pickup and it's respective volume knob. Ignore the VT on this particular diagram, all that is important is the P pickup going to the switch.
  16. Hi everyone,

    Firstly, apologies for necroing an older thread, but the quoted post seems to have close to the info I'm after.

    I have an early 90's Fender Precision Lyte Custom active PJ. It's a pretty mean bass, it's a bit beat up so I'm thinking of using it for my stage beater instead of taking my $4k ray out on the road. I'm considering adding a series/parallel switch so I can run the P and J pups in serial if I like, maybe get a little added lower mid that the Ray has in spades, and perhaps tame some of the hum on the J pup. The bass is fitted with a 2-band active pre and a blend pot with centre-detent as per the attached layout, and I run this right in the middle 50/50. I can take a pic of the control cavity when I get home from work, as I actually need to replace the battery clip on this bass anyway.

    My question is... all of the 3 quoted options look possible, out of the 3, which would be easiest for me to complete? Would a push/pull switch on the vol pot work with any one of these?

    Thanks in advance!

    pblyte1.jpg 127052310_10157519443601994_9067133614896325700_n.jpg
  17. bigtone23


    Dec 10, 2014
    Denver, CO
    This may be more tricky than the above passive options. Pretty sure the P Lyte uses a proprietary preamp with circuits attached to each pot and ribbon cables connecting everything. Adding push/pull pots and a series/parallel switch to the blend control would require some next level wiring adaptation to work.
    Running the pickups in series won't really help tame the J pickup single coil noise, though. TBH, I haven't had great luck running a P and J pickup in series. The P pickup, being already in series, has enhanced low mids and softened highs. Running that into another pickup in series will make that enhanced lows/softer highs even more dramatic. It tends to sound rather muddy. Running two J pickups in series sounds great, though. The clarity is still there.
    It may be more effective to just get a set of pickups that already have a hum canceling J pickup and a preamp that has a mid control, preferably sweepable mids, so you can dial in that Stingray low mid thing more easily. I usually fake a Stingray tonality on my active J basses by setting the blend more towards the bridge pickup and boosting some bass and treble while cutting some mids.
    Your mileage and results may vary.
    Fazz1977 likes this.
  18. Thanks for the input!!!

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