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Series/Parallel with active pup's

Discussion in 'Pickups & Electronics [BG]' started by Minimalist, Nov 30, 2004.


  1. I'm thinking about adding a series/parallel switch to my P/J. Since I have active SD lightnin rod's I'm not sure if this can be done?
     
  2. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Memphis
    Shouldn't be a problem. As long as the pickups have the battery connection, you can change positive and negative connections around.
     
  3. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    actually, I'm not so sure it can be done. Or done successfully.
    Active pickups have a preamp on board, so putting the neck ground of an active pickup into the bridge hot of another active pickup would have very odd results. You'd be feeding the output of one preamp into another preamp
     
  4. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Memphis
    David may very well be right, but I could also see it working.

    Only one way to be sure. Touch the negative from one pickup to the positive of the other. How's it sound? Good? Do the mod. Bad? Don't. Let us know either way.
     
  5. I will try it later tonight and let you know. :)
     
  6. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    It won't work. If you have active pickups then you can only wire them in parallel.
     
  7. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    My understanding is that you could potentially fry the pickups by trying.
     
  8. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    Possible but unlikely. It depends on the design of the preamp in the pickup.

    Either way, don't try it. It has no chance of success. You cannot treat a preamp output as if it were a passive coil. They simply are not the same thing.
     
  9. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Memphis
    I'm not sure I can see that it would hurt anything, but I'm definitely being shouted down, so don't try it.
     
  10. I'm not sure if i would hurt, but after some thinking (sometimes I do that :D) I came to the conclusion that by wiring the pup's in series I'll cut off one preamp from the battery. Correct me if I'm wrong.
     
  11. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    You are not wrong. An active pickup will have 3 leads: positive voltage, ground, and output. The active circuit uses the ground and the positive voltage wires to be powered. The ground goes to the battery negative and the other goes to the battery positive. The ground lead is not a signal input and will not function as one.

    A passive pickup has no active circuit. It has two leads that are attached to either side of the coil. Neither wire is an input or an output, they are simply endpoints of a coil of wire. This is why a passive pickup can be wired in either series or parallel. A passive pickup is only a coil of wire.

    An active pickup is that coil, but it is attached to a built in preamp. The preamp input is connected to the coil. The preamp output is placed on a wire. The other two wires are used to power the preamp. The bottom line is that an active pickup is much more restricted in how it can be wired.

    Does any of this make any sense? I'm coming from a background of a BS in Electrical Engineering followed by 18 years of job experience. So, I don't know if my explanation is clear or not to someone without a similar background.
     
  12. geshel

    geshel

    Oct 2, 2001
    Seattle
    Even if it didn't hurt the pickups, and both preamps would function (assuming they function properly, the same as before), the sound would not change at all. The tonal difference that happens when you switch passive pickups from parallel to series happens because of an interaction between the two coils (the inductance and resistance is increased, lowering the resonant frequency).

    With the preamps isolating the coils, this interaction wouldn't happen.
     
  13. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    Geshel, Bob,
    thanks for the good technical explanations.
     
  14. Thanks guys for the excellent explanation. I even understood. it. ;)
     
  15. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    Hehehe, I'll count that as my good deed for the day.

    BTW, is the sound of the bass lacking something or did you just want to try something different?
     
  16. This is kind of a project bass. It's a MIM P and I'm getting really happy with the sound and versatility. The pickups are (almost) perfect for what I want but I thought with a series/parallel configuration it would be even more versatile.
     
  17. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    One option is to pull the active SD pups out and put in passive SD pups. Then you can do the series/parallel switch. Of course, the sould will end up being different than it was.
     
  18. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    Never saw this thread before but someone else just posted the same question which I responded to. DavidWilson did also and made reference to this thread.

    I'm guessing nobody here has actually done this and neither had I cause I have no onboard controls. I couldn't see any reason why it wouldn't work. I rarely play actives but happen to have a set of active EMG J's in a bass on the wall. Everytime I wasn't thinking of something else, it kept popping into my gord so I did it to get it out of my system. Worked just like it does on passives. Nothing blew up, nothing melted down, no racket, distortion, whatever. Just series/parallel tone.
     
  19. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    very interesting lunkfur, thanks for trying that
    I thought there could be some issue with feeding the output of one preamp into another - not blowing anything up, but maybe distorting.
     
  20. Ncognito

    Ncognito Banned Commercial User

    Jan 8, 2002
    Hoffman Estates, Illinois
    Owner, Xsonics Bass Cabinets
    Hey luknfur

    I want to try series on one of my basses too. How did you wire the EMG's for series.

    Thanks in advance for your help!!