Different alloy on pole screws

Discussion in 'Pickups' started by hamerfan, Oct 29, 2017.

  1. hamerfan

    hamerfan Senior Member

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    What were your experiences with different polescrews?
    What were the sonic outcome when you changed them?
    I got a wrecked 52 P90 and let it rewind. Great outcomes, but since this very early P90 uses very rough casted A3 (which were very hard to remagnetize) with a very low gauss reading on the poles. My idea now is to look for 1022 screws to get more magnetic flux and a brighter sound.

    BTW has anybody a surplus of 1022 or even 1020 screws? The only source i know is fxaddict on ebay, who tries to compell international orders with prohibitive costs (50 USD for an order of 6 screws). Thanx.
     
    Last edited: Oct 29, 2017
  2. cooljuk

    cooljuk Transducer Producer Premium Member MLP Vendor

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    I'm confused. Why do you find the early P-90 A3 magnets to be very hard to remagnetize. A3 has a lower maximum saturation than other AlNiCo types, making it more easy to magnetize. If you mean that they have only a single polar face ground flat (while the North side remains rough) I still don't see how that makes them more difficult. I do it all the time, and have done so with at least three types of electronic magnetizers. A magnetizer of significant power will have no problem at all with them.

    Also, why would you want to change the pole screws? The sound of early 50's P-90s is considered among the best by many. I get that sound preference are unique to the individual player/pickup/instrument but I've just never heard anyone pickup up an early 50's Gibson and say, "Ya, it's nice. ...but those pole screws. That alloy is really leaving something to be desired." Just a new one to me, but to each his own.

    As to the sound difference, it's slight. Most certainly WAY less significant of a change than you experienced by having the coil rewound. What you will experience in sonic difference is a brighter (some may say more "brittle" or "harsh" or "choppy") sound. Again, only slightly different. So many other factors alter the sound far far more than the alloy of your pole screws but, in a vintage 50's P-90, little differences in things can be heard as every little part counts so it's not completely insignificant.

    If you want to send me the original pole screws that you don't like, I'll gladly send you a set of modern steel 1022 pole screws in exchange. I'll even age them to match your pickup/guitar and cover the international shipping. I honestly don't recommend doing this but, if you're going to do it anyway, I will accommodate you.
     
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  3. Antigua

    Antigua Senior Member

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    Wouldn't it make sense to change out the magnets? (BTW, don't lose the magnets)
     
  4. LtKojak

    LtKojak Senior Member

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    I beg to differ here. The A3 is the only of all Alnico grades that can be charged to fully saturation with a household N52 Neo magnet, as long as its physical shape is bigger than the mag bar. The capacity of these particular old mags to hold a charge is a completely different thing. The lesser the charge, the thinner they sound.

    PM me your address and I'll send you either 1022 and/or 1018 filister screws. Your choice. No charge! (pun intended)

    HTH,
     
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  5. hamerfan

    hamerfan Senior Member

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    The charging of these rough cast magnets created a very uneven charge along the polar face. I tried to get a more even charge, which is very easy with my modern A5s. I also recognized that initial charge was far higher than the charge after it settled.
    Now i have 230 gauss peak at the poles, while a degaussed A2 SD Ant P90 measures 370 peak.
     
  6. hamerfan

    hamerfan Senior Member

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    They are non standard sized rough (and I mean rough) magnets. Nowadays magnets don't fit.

    image.jpeg image.jpeg image.jpeg

    Just to straighten it out: last pic was taken before rewind!
     
    Last edited: Oct 30, 2017
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  7. cooljuk

    cooljuk Transducer Producer Premium Member MLP Vendor

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    Those magnets are very typical of early 1950's P-90s.

    What are you using to charge them?
     
  8. cooljuk

    cooljuk Transducer Producer Premium Member MLP Vendor

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    If you've already had the coil rewound, the magnets replaced, and are now considering changing the pole screws, you should probably also consider just replacing the pickup with something modern.

    Honestly, all you have left from the original pickup, after those changes, is the keeper bar, the baseplate, and a cracked and warped polystyrene bobbin with a limited lifespan.

    You might be better off putting the original parts back in (can't do that with the coil, obviously) and selling it as repaired/rewound to fund a new pickup that you like the sound of. I'm not suggesting you buy one of mine, in fact, if you don't like the sound of your original P-90, you probably won't like many of the P-90s I make. Just that you find something that you like the sound of and is in good condition, rather than trying to mod that one around a dying bobbin with nothing much original left.
     
  9. freefrog

    freefrog Senior Member

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    Late answer, chiefly 'cause I'm very busy.

    In MY experience and experiments, any change of components is able to change the specs of a pickup. Sometimes, it makes no perceptible difference. Sometimes it does. It's really a question of synergy between parts IME.

    Statistically, different screw poles gave me different shades of tones more often than similar sounds, in P90's as well as in humbuckers. And it was not only a question of alloys: plated vs unplated screws would make a tonal difference too, as well as the size and shape of screws (I've modified baseplates and sawed screw poles more than once in order to check this idea).

    Now, this difference is not necessarily measurable in some conditions: someone who focuses on the transfer function of coils, for example, would probably conclude that it makes "no difference". Other testing strategies are necessary to make it obvious...

    All that being said, personally, I wouldn't change the poles of a breakable vintage P90. YMMV. Do (and think) what you want and be happy...
     
  10. hamerfan

    hamerfan Senior Member

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    Thanks freefrog, thats what i wanted to know.
    The coil was completely toast when i got it. The bobbin was repaired with glue before. Then Used by the previous owner until the coil went south. David from Sigil Pickups tried to save the wire, but gave up on this. The glue soaked into the coil. So now its a new coil wound by David on a Throbak bobbin (42.9mm spacing), wound to 6.9k with 42awg PE.

    I report back when i put in the screws from Pepe. Thanks man.
     
    Last edited: Nov 2, 2017
  11. Antigua

    Antigua Senior Member

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  12. freefrog

    freefrog Senior Member

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    You're welcome.

    Ah, OK, I've a better understanding now about your P90... In this situation, I wouldn't hesitate either to experiment with various parts.

    To my quick answer above, I'll just add a few other hasty words:

    -if you experiment with 1022 poles, you might notice a bit more tonal "hardness", if not "harshness"...
    -... BUT I don't know if I must evoke a "warmer" or "brighter" sound according to the grade of steel used (following the equation "lower grade = warmer tone"), as it's often the case in online depictions: IME, it's more complex and/or less predictable than that with a potential effect on the loudness of the pickup & on the filtering of harmonics (effect depending itself on the pickup as a whole, which is often more than the sum of its components IME)...
    -anyway, I'd find imprudent to generalize about screw poles (or any other part of the magnetic circuit) beccause apparently, their actual composition is not always faithful to the recipe officially applied : some pickups builders might say here that alloys vary from batch to batch under a same name... or even that parts of supposedly different alloys can actually be much closer to each others than claimed by the numbers on various bags...

    All that explaining why personal suppliers like Pepe and individual empirical experiments are the only ones to trust with such things, IMHO & IME. So, let us know if you notice a difference or not, and what it is!

    More later, maybe. Life is still busy here...
     
    Last edited: Nov 3, 2017

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