Critique my schematic...

Discussion in 'Pickups & Electronics [BG]' started by bluesavageraff, Jul 23, 2009.

  1. bluesavageraff


    Jul 7, 2009
    So I'm gutting my Jag bass and totally rewiring it (for fun of course). I'm new at this so I will definitely some input on my design.

    I'm going to have individual volume and tone controls for each pickup. Then I also want to be able to switch between two different capacitors for each tone control.
    From here I want a series/parallel switch and then a kill switch.

    Here's the schematic:
    (Red: Bridge +, L. Green: Bridge -, Purple: Neck +, D. Green: Neck -, Blue: General Hot, Black: Ground, Yellow: other)
    *Note: In order to make this more readable, I tried to draw this in a linear fashion, i.e. components are not in position that they will be in on the bass.*

    I most importantly want to know if this type of set-up will even work. If it can, did I draw it up correctly?
    Lastly any input on possible cap or pot values would be much appreciated.

    Thank you.
  2. JTE

    JTE Gold Supporting Member

    Mar 12, 2008
    Central Illinois, USA
    It's a little hard for me to see because it's not really a schematic (which shows functionality) but more a pictoral diagram of the finished product.

    But I think I see a problem in the Series/Parallel switch. The hot from the bridge PUP is connected to its pots, but the only output from that part of the circuit is grounded. The red from the bridge tone pot goes to the S/P switch, and that same lug is connected to ground. And because it's not a real schematic I can't see the swith logic to tell what's going on there. But it looks close, I just don't see why the volume and tone control output is being grounded.

  3. The killswitch is improperly wired.
    Switch the Jack + with the center terminal.

    The neck volume and tone pots are wired backwards.
  4. As for the hot leads... I also like attaching them to the wiper terminal (center). I see what you're doing with the kill switch in that you want to ground it instead of just cutting the circuit so take line6man's advice... and I'd have to agree that the ser/par switch appears a little wonky.

    1. The red is sent to ground no matter what s/p switch position yet it's the bridge pup hot lead.
    2. In the "up" position the s/p switch causes a looped circuit with a tap rather than a terminus.
    3. IN the "down" position the s/p switch appears to disconnect the hot leads from both pickups and only leave the ground (-) leads in the "circuit"

    It could be that I've already had too much wine after a mentally exhausting day of writing code but this is my professional opinion with a +2 buzz.;)
  5. bluesavageraff


    Jul 7, 2009
    So the kill switch should go (from top to bottom)
    HOT in
    HOT out
    GROUND ?

    As for the pots, you mean they're backwards as in they will need to be turned the opposite direction to give the desired effect, correct? I figured as much, I drew it up this way just to make the drawing cleaner.
  6. bluesavageraff


    Jul 7, 2009
    Ok, the series/parallel switch confuses me too. I used a diagram off of "alex's axe hacks". I didn't think it looked right, but I saw other similar diagrams.

    Does anyone have a drawing of a proven one?

  7. Yes.

    What i mean is that the outer terminals should be switched around on the neck pickups volume and tone pots.
    The way you have them, the pot will work backwards and the taper will be wrong.
  8. There are two types of series/paralle switches, one for the coils of a humbucker, and one for wiring two seperate pickups series/parallel.

    This is an old drawing, so it's crappy, but here is the correct series/parallel wiring for this application:
  9. Angus

    Angus Supporting Member

    Apr 16, 2000
    Palo Alto, CA
    Avoid star ground. It's so totally unnecessary that the mess it will cause (and the huge solder joint necessary) will be in no way worth it. You can't have ground loops in a passive bass.
  10. bluesavageraff


    Jul 7, 2009
    You would recommend just soldering to the pots? It seems like a lot of grounds for that...
  11. Angus

    Angus Supporting Member

    Apr 16, 2000
    Palo Alto, CA
    You have to do the same number of ground connections more or less no matter what, and star grounds make the cavity sloppy (and are a common point of ground problems when people don't solder them perfectly because it's not the most ideal mechanical solution).

    The ground reference is the same everywhere, so you don't need to pull it all from the exact same point.
  12. bluesavageraff


    Jul 7, 2009
    First of all, thank you to everybody for your help.
    Secondly, I drew up a new design. I used a master volume and blend instead of two volumes.


    I didn't bother to hook up the grounds. I'm still not sure what I'm going to do with it all anyway.
  13. If you want to do both a blend pot and a series/parallel switch, you are going to want to use a 3PDT switch to bypass the blend pot when you're in series mode, otherwise you will get a volume drop unless you have the blend set fully to the neck position.

    Here is a diagram a drew a while back for this type of setup:

    I can redraw it for the two tones and the capacitor switches if you want.

  14. FWIW, the ground from the blend pot should be on the terminal directly above where you have it.
  15. bluesavageraff


    Jul 7, 2009
    Thank you. You have been very helpful. I think I'm just going to go back to the two independent volumes.

    I'm going to get on this project next weekend, so I'll post updates and (hopefully) a final product then.
  16. bluesavageraff


    Jul 7, 2009
    If I use two independent volumes, then there is no element that "consolidates" the signals from the two pickups. Can I just solder both leads into the pole on the killswitch?
  17. slyjoe

    slyjoe Supporting Member

    Jun 28, 2008
    Valley of the Sun (AZ)
    Yes - the blend pot doesn't consolidate the signals - it is two independent volume controls also, with the outputs tied together.
  18. bluesavageraff


    Jul 7, 2009
    Thank you.