How to identify humbucker magnet type?

Discussion in 'Just Pickups' started by daley.bc, Jun 13, 2019.

  1. daley.bc

    daley.bc TDPRI Member

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    Hi all

    I have some reissue fender wide range humbuckers that have been pulled apart and put back together many, many times. I can't remember if i switched the baseplate or magnets around on either the neck or bridge. I can identify the coils easily but is there a way to visually identify if the bar magnet is alnico 2 or 4/5 etc? Or is there some other test that I could perform?

    Thanks.
     
  2. DHart

    DHart Friend of Leo's

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    Good question. That I would like to know the answer to, also.
     
  3. Zepfan

    Zepfan Poster Extraordinaire

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    Alnico2 have a green mark on them, Alnico5 have a red mark on them. Placed on them by most manufacturers. Don't know what other colors are used for the 3, 4 and 8 mags.
     
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  4. vanr

    vanr Tele-Afflicted

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    I know Ceramic magnets are dark in color. Alnicos are silvery.
     
  5. rigatele

    rigatele Tele-Afflicted

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    Check the Gauss reading with a magnetometer.
     
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  6. myteleguitar

    myteleguitar TDPRI Member

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    Is that possible if someone said alnico 5 pickups but has a black bar under the pickups? Thanks.
     
  7. Ronkirn

    Ronkirn Doctor of Teleocity Vendor Member

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    Checking the gauss alone could be misleading.. there are other factors in play.. it would be much like checking to see how much gas is in the tank to know how far a car could travel..there's just other "stuff"ya gotta know.

    r
     
    Last edited: Aug 1, 2019
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  8. rigatele

    rigatele Tele-Afflicted

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    As someone pointed out above, ceramic is easy to spot. None of the other formulas are as strong as A5, so you can at least identify that by Gauss. It is true, it would not be sufficient to sort out the rest. But in a lot of cases, it would be A5. So you could halt the investigation right there.
     
  9. Ronkirn

    Ronkirn Doctor of Teleocity Vendor Member

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    One of the methods more experienced builders use to "sculpt" the sound of their pickups is to regulate the strength to which the magnets are magnetized.. thus it's entirely possible to have A3's at a strength higher than that of A5's ..

    The origin of the magnets are a factor too.. not all A5’s etc., etc., are calibrated to the same metrics..

    as with any facet of building guitars there are no hard fast rules... There has been a ongoing quest by those not fully embroiled in the world of creating these things to quantify everything.. the ultimate fool's quest...

    and Gauss doesn't actually measure the strength of a magnet, it measures flux density…. Thus its possible to have a larger magnet of less flux density that’s stronger than a smaller one with higher density. The opposite is true too..

    But… all this is only important if “you” are making pickups professionally and need to be certain a specific model is uniform from one run to the next.

    If you are a home winder… it really isn’t too important at all.. because you will not be able to sculpt a specific “sound” out of a pickup with “Home brew” technology. You can only shuffle off toward a generic sound.

    However.. with even very basic tools and procedures, one can make a pickup, never even touching a pencil, paper or calculator, that will amaze you with its sound.. so do not allow the professed complexity some want to share, to dissuade you from making your own..

    Even Lindy, Jason, Bill Lawrence, Curt Novak, Owen Duffy, Seymour Duncan, and me, et al … sat down and made their first sometime in the past… ya gotta start somewhere..

    r
     
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  10. rigatele

    rigatele Tele-Afflicted

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    That is not a good idea, because the flux density of a partially charged magnet is not stable.
     
  11. Ronkirn

    Ronkirn Doctor of Teleocity Vendor Member

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    and what does an unstable flux density do and what causes it to be unstable?

    r
     
  12. rigatele

    rigatele Tele-Afflicted

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    It renders the bulk material more susceptible to gradual demagnetization due to thermal and mechanical stresses in the natural environment.

    All magnetic materials are always fully magnetic. The atoms in them have an intrinsic magnetic field due to the orbits of their electrons. However, the orientation of these atomic scale "magnets" are usually random. Because they tend to align with each other, they line up locally, in microscopic regions called "domains". Because the solidity of a solid is due to the participation of the atoms in a connected structure (often crystalline or lattice-like), these domains are fairly fixed, because the atoms are "locked", really, have preferred orientations within the material.

    The domains normally are randomly oriented, so that as a whole, they mostly cancel each other out. A strong external magnetic field causes the magnetic fields of the domains to align in the same direction. That is what we call "magnetization". There is some hysteresis, or "stickyness" to the direction of the field of a domain due to the lattice structure mentioned above. However, environmental heat (even room temperature) and mechanical impacts can change the direction of an atom, and thus collectively, an individual domain. In the random state, it is unlikely for both statistical reasons, and because of energy conservation laws, that the bulk would become significantly magnetized on its own. When a strong magnetic field is temporarily applied and the domains are mostly aligned, the bulk exhibits a magnetic field that is the sum of the domain fields. In that case, it is considered "fully magnetized". The thermal and mechanical effects still affect individual domains but since they are embedded in a strong bulk field, the threshold value of the thermal or mechanical energy required to change a domain is greater, due to the slight "stickyness" or hysteresis effect. Another way to express this, is that the domains "support each other". In the case where only a portion of domains are aligned ("partial magnetization" of the bulk), the thermal and mechanical thresholds required to change domain orientation are lower.

    Thus a strong self-supporting field discourages the long term change in magnetic strength. It is why a "keeper" can help protect a magnet against demagnetization. A partially charged magnet has a weaker overall field, and this makes it likely to lose magnetization at a greater and more unpredictable rate than a fully charged magnet.
     
    Last edited: Aug 2, 2019
  13. Controller

    Controller Friend of Leo's Silver Supporter

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    Great explanation, thanks!
     
  14. Ronkirn

    Ronkirn Doctor of Teleocity Vendor Member

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    That is correct however it diesel;t preclude pickup makers/designers from using different levels of magnetization as a tool to sculpt the sound of the pickups... also. many relish the sound oof vintage pups.. pickups who's magnets have degraded over the years...

    r
     
  15. rigatele

    rigatele Tele-Afflicted

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    The degree of magnetization can not affect the inductance or any other electrical parameter of a pickup. Thus there can be no direct influence on tone. There are only two ways in which it can:
    1) The effect of varying the localized force acting on the portion of string above the pickup, which alters the harmonic structure slightly.
    2) Varying the available output level

    The first is easily controlled by adjusting pickup height, without any change to the magnetics. The second only has an effect on the amp chain as it influences amplifier front end distortion levels, but is a relatively minor difference and easily adjusted by tweaking input and master gain settings on 99% of all amps.
     
    Last edited: Aug 2, 2019
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