How weak is alnico 3?

Discussion in 'Just Pickups' started by AJBaker, Apr 18, 2020.

  1. AJBaker

    AJBaker Friend of Leo's

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    I had a bunch of strat pickups on my work bench yesterday, and played around with them a bit. Using the blade of a box cutter, I noticed that I could lift an alnico 5 pickup off the table with just one or two pole pieces stuck to the blade. To lift up an alnico 3 pickup, the blade had to be touching 5 or 6 pole pieces, otherwise it would fall off.

    Is this normal? Is alnico 3 that much weaker, or have these pickups lost their magnetic charge?
     
  2. boredguy6060

    boredguy6060 Poster Extraordinaire

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    I could be way off base, but I always thought that a 5 was strongest. And that they got stronger the higher the number.
    Stronger doesn’t necessarily mean better, it’s just a way of to differentiate one from the other. I happen to like low powered pickups over high powered ones.

    I’m not as awakened as I thought, I’m going back to bed.
     
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  3. arlum

    arlum Tele-Meister Gold Supporter

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    In my opinion an Alnico 3 pickup has less output than an Alnico 5. It's similar in output to an Alnico 2 but the 2 sounds louder because of the mids it produces. Alnico 3 pickups are used in the neck and middle position of the Eric Johnson Signature. Very crisp and clean. The Alnico 5 in the EJ bridge bumps both the volume and gain for solos. I've owned my EJ Strat for over 10 years and I've never even considered replacing the Alnico 3 pickups with anything else. I think they sound great. I've also played a Telecaster with Alnico 3 pickups. They're bright but not ice picky. Just think "clean".
     
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  4. kbold

    kbold Tele-Afflicted Silver Supporter

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    Not quite how it works. Alnico 2 is stronger than alnico 3. But, there's not much gauss difference between them. They do sound different though.
    Alnico 5 is much stronger (by about twice) than either of these.
     
  5. viking

    viking Friend of Leo's

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    Correct
    And , some even dabble with a8 . Very close to a Ceramic magnet , but not quite the same. I have them in a couple of Gibson 498 bridge pu.
    An a4 is probably also weaker than an a2. a4 gives a really even response across the frequenzies , a8 tend to do the same , but much more powerful. i like both , the a4 in the 490 and the 498 gets the a8 as said.
    A6 and 9 are available ,but I dont think anyone have ever used them.
    And then there is the un-oriented a5 ( uoa5 ) Said to be between a2 and a5 , but I dont have enough experience. I have a humbucker with such a magnet , and it sounds great.
     
  6. viking

    viking Friend of Leo's

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    Oh , and a3 is very weak. Its really only an "Alni" alloy , because it doesnt contain any Cobalt
     
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  7. rigatele

    rigatele Tele-Afflicted

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    There isn't much difference between A2 and A3. Look at the specifications.
     
  8. viking

    viking Friend of Leo's

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    Its not so easy to change poles in a singlecoil pu. It is , however , really simple to change the bar underneath the coils in an ordinary humbucker. Really fun to try , and the magnets doesnt cost much.
     
  9. viking

    viking Friend of Leo's

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    What specifications , lol ?
    The ones from the Chinese factories ?
    a3 tend to be very weak , quite a bit weaker than a2.
    But , the different factories probably differ a bit.
     
  10. rigatele

    rigatele Tele-Afflicted

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    It's funny that you find it funny. Alnico has been around for how many years? The formulas vary of course, but the general types don't vary that much. You can see from many, many charts like this one, that A2 and A3 aren't really very different.


    Table 2. Magnetic Properties of Some Representative Alnico Alloys (Lewis and Jiménez-Villacorta, 2013; Luborsky et al., 1957; M.M.P. Association, 2000)

    Grade BR (kG) HC (Oe) (BH)max MGOe HA (Oe) Operating Temperature (°C)
    Alnico 2 7.2 560 1.65 580 450 Isotropic cast Alnico
    Alnico 3 7.0 480 1.35 500 450
     
  11. viking

    viking Friend of Leo's

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    Its funny that you think its funny that I think its funny.
    What is REALLY funny is that some manufacture PUs with al3 , to resemble " weakened " vintage pu´s ..........now , thats worth a LOL , right ?
     
  12. Rob DiStefano

    Rob DiStefano Doctor of Teleocity Vendor Member

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    In a rough but fair comparison, AlNiCo 5 (cobalt based) rod magnets will have about twice the Gauss rate (strength) as that of AlNiCu 3 (copper based) rod magnets. Can you tell the difference between extremely similar pickups, where the difference is only the rod magnet type? There will be a very Very subtle difference, but don't bet yer life on it.
     
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  13. AJBaker

    AJBaker Friend of Leo's

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    In your experience, if we just look at the strength of the magnetism, can you tell a5 from a3 by holding a piece of metal to the pole pieces?

    In my little experiment, I could lift up an a5 strat pickup by having a knife blade stuck to only one or two pole pieces. On the a3 pickup, however, the knife had to be touching 5 or 6 pole pieces to not fall off.

    Is this normal, or have the a3 rods somehow lost their magnetic charge?
     
  14. Rob DiStefano

    Rob DiStefano Doctor of Teleocity Vendor Member

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    if two rod magnets of the same diameter and length are fully charged, and one is a3 and t'other is a5, there will not be any immediate perceptible difference in "magnetic strength". but if a pair of tele bridge flatware bottoms are each loaded with full charged a3 and a5 rod magnets of the same diameter and length, and you touch the same metal rod to the sides of all six rods for each flatware, you will immediately feel the difference in collective gauss rate.

    to be more precise, i use a spin doctor gauss meter. this is important for me because there is no visual difference between an a3 and a5 rod magnet of the same diameter and length. only metering will instantly tell the difference once they are fully charged.
     
  15. jvin248

    jvin248 Poster Extraordinaire

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    .

    Use your ears to adjust pickup heights and you can get the effects of the different magnet types out of your guitar.

    Strong Ceramic bar magnets down about flush with a pickguard (and an 1/8th inch height difference can be important) are weak enough they can pass for where most set the 2,3,5 alnico up higher. The weaker alnico 2,3 and even 5 cannot get the 'hard driving rock n roll output' of a ceramic pickup closer to the strings. So it really depends what you want to play.

    You can charge the Alnico 5s at a lower gauss, using weaker charging magnets or further from the charging magnets. or over time the alnico 5s lose their charge and weaken 'naturally' (where ceramic does not lose charge) rather than looking for alnico 2 or 3 slugs to build with or swap.

    .
     
  16. Lowerleftcoast

    Lowerleftcoast Tele-Afflicted

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    In a word yes it is normal. As you have noted, an alnico magnet can lose a magnetic charge. In your particular example there is not enough information to know whether the A3 is fully charged or not.

    If you want you can recharge the A3 with a stronger magnet. You can also demagnetize alnico if you wish (some refer to this as *aging*).

    In *almost* all single coil p/u, I use A3 fully charged. YMMV.

    I think there is youtube video of changing mag strength of guitar p/u.

    Alnico has very little loss of strength over time. It can very rapidly lose strength when manipulated with a magnetic field such as speaker magnets or other guitar pickups in close proximity.
     
  17. TimTam

    TimTam Tele-Holic

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  18. AJBaker

    AJBaker Friend of Leo's

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    So I ran those pickups past some rare earth magnets to recharge them and it turns out they had lost their magnetic charge!
    I can now more or less lift up the pickup with the knife sticking to two pole pieces.
     
  19. K-Line

    K-Line Tele-Holic Vendor Member

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    But A2 has a bit higher inductance all else being equal.
     
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