Coil split vs parallel

Discussion in 'The Pickup Place' started by lectric, May 29, 2020.

  1. lectric

    lectric Electromatic

    33
    Apr 7, 2020
    Belgium
    Hi guys,

    Just wondering what your thoughts are about coil splitting vs wiring in parallel...

    I've been reading up quit a bit on this, and the general consensus (please correct me if I'm wrong) is that a coil split sounds more (but still not the same) as a single coil guitar and still has the hum, where as a parallel wired humbucker still has no hum, is a bit more silent that a coil split and still has a warmer tone.

    Are my observations correct? I suppose one could say that since a coil split doesn't really sound like a single coil guitar, a better option would be to have it wired in parallel and buy a 2nd guitar with single coils?

    I also found this which also seems interesting to me. Any ideas on this? The part at 6:23 seems nice… Anyone experience with this wiring, and thoughts?

    Thanks guys!
     
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  2. sgarnett

    sgarnett Gretschie

    380
    Apr 14, 2020
    Kentucky
    I think he said parallel wiring divides the impedance in half. Actually it divides it by 4. Let’s say for example the impedance of each coil when split is 4K. 4K in series with 4K is 8K. 4K in parallel with 4K is 2K. So, the impedance in parallel is 1/4 the series impedance.

    One of the reasons coil splitting does not sound like a single coil is that the geometry of the magnetic field stays more or less the same. The narrower field of a typical true single coil picks up more high frequency harmonics.

    Oddly, the Gretsch 6120 has the pickup volumes wired in reverse as the speaker suggests, but Streamliners do not, and I don’t think Electromatics do either. I’m not sure why the reverse wiring isn’t used on all of them - it works well.

    The “50s wiring” (tone on the output side) is a popular mod on Les Paul and ES335 guitars. It’s also how the master tone is wired on Streamliners, Electromatics, and Players Editions. I’m not sure I see the point of having two tone controls with 50s wiring. They do function independently when separate, but in the middle position the tone controls are in parallel, and affect both pickups. That is presumably why Gibson switched to the modern wiring.
     
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  3. Alanqa

    Alanqa Gretschie

    233
    Aug 22, 2019
    Lancashire UK
    I just rewired my PRS SE with parallel Switching.

    pros: you get a clear bright sound in the ballpark of a single coil but slightly thicker think P90.

    no noise, no more or less than the same pickups in series

    because each pickup is individually switched you can have more combinations

    cons: you need 1 dpdt per pickup whereas you can coil split 2 humbuckers on one switch.

    Technically (on paper) the parallel setting is ½ the output of single coils alone (1/4 of the series output) However in reality this is utterly irrelevant. I find virtually no Volume difference between 1 single coil and 2 parallel
     
    Last edited: May 29, 2020
  4. Alanqa

    Alanqa Gretschie

    233
    Aug 22, 2019
    Lancashire UK
    I can do some sound examples later but not today as I am busy.
     
    Last edited: May 29, 2020
  5. lectric

    lectric Electromatic

    33
    Apr 7, 2020
    Belgium
    First of all, thanks for the reply! Can you elaborate a bit more on the impedance subject? I'm not really into electronics... What does it mean when the impedance changes? I know that impedance is resistance, but what is the effect of a higher/lower impedance in the case of electric guitars?

    Good point on the tone controls wiring… maybe someone has an idea of why he would wire both the tone controls with the 50's wiring?
     
  6. lectric

    lectric Electromatic

    33
    Apr 7, 2020
    Belgium
    Thanks! I don't see the con you mention as something negative actually. Unless I miss something, this also means that if you split the humbuckers with one switch they're aways splith at the same time? Where as with 1 dpdt per pick up you can have one split (or in parallel), while the other isn't, so if I'm correct here, than I don 't mind the 2 dpdt's.
     
  7. lectric

    lectric Electromatic

    33
    Apr 7, 2020
    Belgium
    Thanks, would be great, I assume a lot of people might like that. The sound examples I found were not really thát clear to me, although that from what I've heard, I also seem to prefer wiring in parallel. No pressure though!

    I guess that if one day I really want a single coil sound, I can always buy a single coil guitar. I've been reading up quite a bit the last few weeks, and it already came clear to me why so many guitarists have multiple guitars :).
     
  8. Alanqa

    Alanqa Gretschie

    233
    Aug 22, 2019
    Lancashire UK
    yes that is correct. By a ‘con’ I meant that if you had a mini toggle already wired for coil split then you would need to add another. Same if you only had a single volume pot and no tone.

    obviously you could also wire 2 dpdt switches as individual coil splits.
     
  9. sgarnett

    sgarnett Gretschie

    380
    Apr 14, 2020
    Kentucky
    No, that is incorrect. “Output”, resistance, and impedance are often used interchangeably on guitar sites, but they are not the same at all.

    Resistance is independent of frequency. Grossly oversimplifying, impedance is frequency dependent.

    Resistance is used sometimes used as very-flawed proxy for “output” amplitude because, for a given wire size, resistance is proportional to the number of turns, which is proportional to the inductance. High turn count pickups often have finer wire, further increasing resistance. That does not even begin to tell the whole story though, and many other factors together determine the actual output.

    Output voltage amplitude at lower frequencies for an individual coil is proportional to the inductance. Let’s ignore high frequencies for the moment.

    Put two coils in series, and it’s like putting two batteries in series. It doubles the amplitude at low frequencies. It does not increase the current it can drive, and increases the source impedance. We'll come back to that. Note that Perceived volume is not linear, so doubling the amplitude increases but does not double the volume.

    Putting two coils in parallel is like putting two batteries in parallel. With no load, the voltage does not change. What does change is the amount of current they can provide under load.

    More oversimplification: let’s ignore internal capacitance in the pickup, and pretend it is a pure inductor. That means its impedance increases with frequency. With no load, that doesn’t matter, but with a load, higher frequencies will be attenuated.

    The volume pot itself provides a load. The capacitance of the cable provides a load that tends to be capacitive, meaning it loads high frequencies more than low frequencies.

    Output voltage is proportional to the load impedance and inversely proportional to the source (pickup) impedance. Together, they divide the voltage.

    So, coil splitting cuts the amplitude of the fundamental in half, assuming a relatively high impedance pedal or amp input. It also cuts the impedance in half, making it less sensitive to treble loss in the loads.

    Parallel wiring will have the same amplitude as a single coil with no load, but as the load increases, the parallel combination will be less sensitive to it.

    The catch is, the coils are in phase at the fundamental, but they can be a little out of phase in the harmonics. So, there’s a little phase cancellation between coils in the harmonics.

    Even in that long explanation, I’m leaving out a LOT, which is why designing working pickups is easy, but designing really good pickups is hard. There’s also some art to it. If you really account for every detail, the math becomes impossibly complex.
     
    Last edited: May 29, 2020
  10. Scott Fraser

    Scott Fraser Country Gent

    Jan 14, 2012
    Los Angeles
    It's more complicated than that. Resistance is a measure in DC circuits, & impedance is a measure in AC circuits. Impedance incorporates resistance, plus capacitance, plus inductance. But both are measured in Ohms.
     
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  11. sgarnett

    sgarnett Gretschie

    380
    Apr 14, 2020
    Kentucky
  12. Alanqa

    Alanqa Gretschie

    233
    Aug 22, 2019
    Lancashire UK
    I get the basics but I was oversimplifying for the sake of clarity. I have met many guitarists who treat impedance as a true and final measurement of output. I prefer to use my ears.

    Anyway my point is (and always was)... don’t get hung up on the maths, SOUNDWISE parallel sounds single coil’ish’ And is hum free.
     
  13. lectric

    lectric Electromatic

    33
    Apr 7, 2020
    Belgium
    Thanks for all the answers! One more thing...

    In the above youtube clip, he says at 6:08 that the function of the pot doesn't change, but the actual application changes in terms of the direction it's going... What exactly does he mean by this?

    Thanks!
     
  14. sgarnett

    sgarnett Gretschie

    380
    Apr 14, 2020
    Kentucky
    That’s a poor choice of words. The pot still functions as a volume control, but swapping the input (pickup) and output connections at the pot allows them to function independently when both pickups are selected. Rolling one pickup down will no longer reduce the volume of both pickups.
     
  15. Tadhg

    Tadhg Gretschie

    181
    Aug 8, 2019
    Qld - Australia
    I thought - and I'm open to correction - that the better way of saying it was that, with PAF spacing, picking up the frequencies at different points on the string (over each coil) causes some phase issues which lead to phase cancellation of higher frequencies? Which is why Mini Humbuckers and partially also true for FilterTrons (along with other factors for the FT's) are typically brighter than PAF's. Whereas, with only a singular field and coil location for the single coil, there's no phasing, no frequency cancellation with single coils.

    That's not dissimilar to what you're saying here...

    Pretty sure I also heard PRS saying things like that when he was discussing the pickups he built for his "Paul's Guitar", which, effectively, appear to be mini humbuckers. They're definitely narrower coil spacings.


    On a separate point, it's probably worth noting (for the sake of the thread) that coil splitting and coil tapping aren't the same thing. Many (most?) guitars these days seem to come with splits, not taps.
    Further, it's worth noting that the (not uncommon) 4 position Tele switch mod is to add a series option for its two pickups, where the standard middle position is parallel. So, a Tele with a 4 way switch gives an approximation of the effect, though with even wider spaced and unevenly wound coils.

    Open to correction on any of that....... Just worth having it all there in the discussion. I'm pondering getting the 15 year old a strat-style guitar (might build him a kit as a father-son project), thinking it'd be fun to put a Tele bridge pickup and a Strat bridge pickup together in the bridge, and have it selectable as either pickup, series or parallel (think that'd be three push/pulls!). One would hope it'd be versatile. :confused:
     
  16. DennisC

    DennisC Synchromatic

    Age:
    37
    914
    May 11, 2017
    Germany
    This would really be versatile.

    But, tbh, ... this is all cool and stuff, and working out a wiring is a big part of the fun, but ... most time, the standards are used anyway.

    ... and a typical Tele-fourway will switch one pickup on the hot side, one on the ground side, leaving it hanging from hot. Acts as a hum antenna then, picking up whatever is around - I'd do such things with a four pole switch. Works finer, better, ... there are not 4P4T, only 4P5T available ... for each two coils of whatever arrangement (one pickup, two, ...), one of these might work as 1, 2, 1+2, 1*2, off - and then another one on top for two pickups/sets of two coils ... three 4P5T switches for two HBs or something ... uh ...

    Build one together! Sounds totally like the thing that could convince me that having kids is cool after all (... I still prefer being the slightly perverted uncle or something, hahaha...).
     
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  17. sgarnett

    sgarnett Gretschie

    380
    Apr 14, 2020
    Kentucky
    @Tadhg, there is a flaw in both your wording and mine. Sometimes it is difficult to find the right balance between pedantic accuracy and clarity for the audience.

    The magnetic fields of the two coils are not independent. The lines of flux must complete the circuit from the North to South poles of the magnet and back through the magnet itself. Both coils are in the same field. The construction of a hum bucking pickup reverses the orientation/polarity of the flux lines for each coil, but they are mostly the same lines of flux. I say mostly because not all of the flux lines actually pass through the coils. Pole screws protruding out the back of the pickup, for example, allow more of the flux lines to bypass the coils.

    So, the humbucker is actually sensing a window, not just two points. Some phase cancellation occurs within that window.

    Splitting the coils does not significantly change the geometry of the magnetic field.

    Note however that shorting one coil DOES change the time-variance of the field in response to string movement, but not necessarily in a desirable way. That’s a topic for another cup of coffee though ....
     
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  18. lectric

    lectric Electromatic

    33
    Apr 7, 2020
    Belgium
    OK, thanks! What you said is exactly what I understood too, and I seem to prefer that over rolling down the volume of one pickup and at the same time reducing the volume of both pickups. It would've remained clear if he didn't use the sentence with poor choice of words :), so thanks!

    @Tadgh: I'm new to electric guitars, and reading up on coil split vs wiring in parallel, I already encountered coil tapping, so I was aware of the difference. Thanks for mentioning it anyway, it seems that a lot of people confuse the two for some reason.
     
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