Inductance and Tone

Discussion in 'Pickups & Electronics [BG]' started by Llewellen, Jun 20, 2019.

  1. Llewellen

    Llewellen Guest

    Dec 23, 2016
    In my quest for a set of J bass PUs to replace the stock ones on my bass I keep running into contradictory and/or confusing information. This time with respect to inductance.

    One brand that I'm looking at offers a J bass set with 5.0H at the bridge and 3.4H at the neck. My bass uses the same size covers at both positions so I asked about how to order that. I was told just to order two bridge (longer) versions. What about the different inductance? Will you wind one of the longer ones with lower inductance for the neck position? Response - not necessary, doesn't really matter but we'll do it if you ask. Which, of course, begs the question of why they offer the set with different inductances.

    I don't much care about the different output levels from different inductances because I will be using a volume pot on each PU or possibly a master volume and a blend.

    My question is what effect will the higher inductance in the neck position do to the tone of that PU?. I read that, all other things being equal, higher inductance will produce more bass response. I don't necessarily want more bass response from the PU in the neck position.

    Of course, as was offered by the maker, I can specify the lower inductance for the neck PU but before doing so I would like to understand what's at work here.
  2. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    The more wraps of wire on there the more Inductance it will have, accompanied by more output, but also lowering the resonant peak.
    Inductance is resistant to changes in current, so the higher the Inductance the lower the resonant peak & the overall resonant frequency.

    A really high output pickup will normally also have lots of lows & less highs.
    This is one of the reasons single-coil pickups are generally brighter.
  3. Llewellen

    Llewellen Guest

    Dec 23, 2016
    Thanks. That's more or less what I thought I knew. Which makes me wonder why this highly regarded pickup winder said what they did.

    Another way of looking at this is that the strings have greater amplitude in their vibration at the neck PU location (being closer to the 12th fret) which induces more current and therefore requires less windings/output in order to mate and balance properly with the bridge PU.
  4. Llewellen

    Llewellen Guest

    Dec 23, 2016
    This is interesting. The original J Bass PU specs as listed by Fender. Lower inductance on the neck PU. The ones I'm looking at for retrofit have even higher inductance at the bridge.

  5. ihaveaquestion


    Jan 9, 2018
    When they are the same size, it's usually both with the neck size
  6. Llewellen

    Llewellen Guest

    Dec 23, 2016
    Maybe so but on my Warwick Corvette Basic they're both the longer bridge size.
    ihaveaquestion likes this.
  7. I would definitely have them underwind the neck pickup. Otherwise you'll end up with pretty radical height adjustments to get their outputs balanced.

    FWIW, inductance, like resistance is just one part of the recipe, and on its own probably not too useful. But it sounds like the magnets and wire gauge are otherwise the same so it's a safe bet the neck pickup is simply an underwound version of the bridge pickup.
    Llewellen likes this.
  8. Llewellen

    Llewellen Guest

    Dec 23, 2016
    I agree. I don't want more output (or extra bass) from the neck PU. Yes, the neck and bridge use identical magnets (alnico II) and wire, the only difference being the number of turns.
  9. john m

    john m Supporting Member

    Jan 15, 2006
    Also: Adding turns adds more parasitic capacitance ( between turns). This lowers resonant frequency.
  10. nilorius

    nilorius Inactive

    Oct 27, 2016
    Riga - Latvia
    If you want 2 bridge j-pickups, think about 1 humbucker or 2 bridge pickups beside the bridge. For the tone, if you leave passive electronics, stay with with the tone.
  11. ctmullins

    ctmullins Dominated Gold Supporting Member

    Apr 18, 2008
    MS Gulf Coast
    I'm highly opinionated and extremely self-assured
    What I learned from Bill Lawrence is that (all else equal) lower inductance yields slightly lower output but more clarity. “More clarity” is, I think, another way of saying “higher resonant peak”. So this is not new information, as @Killed_by_Death and @RobbieK have already pointed out.

    It makes more sense, and I’ve had more satisfactory results, from lower inductance in the neck position.
    Phaidrus and bigtone23 like this.
  12. Llewellen

    Llewellen Guest

    Dec 23, 2016
    Agreed and If I end up going with the PUs in question, that's what I will specify.