Help - Stupid P90 question here.

Discussion in 'Just Pickups' started by bsman, Aug 16, 2019.

  1. bsman

    bsman Tele-Afflicted

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    I was just playing my LP "Junior Special P90" and wondering idly what would happen if I took the bridge or neck pickup and just rotated it 180 degrees and put it back. Would it be hum cancelling?
     
  2. simoncroft

    simoncroft Tele-Meister

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    I'm afraid not. For a humbucker you need the two coils wound opposite ways and the magnetic polarity to be reversed also.

    Here's part of a tutorial I made a while ago:

    Screen Shot 2019-08-16 at 19.47.48.png
     
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  3. Tim S

    Tim S Tele-Holic

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    But if you flipped the magnetic polarity by rotating one coil (in this case, a P90) and swapped its leads, would that lessen the hum?
     
  4. beyer160

    beyer160 Friend of Leo's

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    No. To do that you need to invert the waveform coming from the pickup by reversing the hot and ground wires, not just moving the pickup.
     
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  5. nojazzhere

    nojazzhere Poster Extraordinaire

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    Sorry.....if your P-90 hum is bothering you, you'll just have to buy a true humbucker and change it out. "HUM" is what we generally have to accept and deal with because we love single coils....;)
     
  6. bsman

    bsman Tele-Afflicted

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    Oh no - you misunderstood me! I was listening to the low, musical hum from the LP through my little 6v6 amp and idly wondered what the result would be. I love single coils!
     
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  7. Tim S

    Tim S Tele-Holic

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  8. simoncroft

    simoncroft Tele-Meister

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    That would indeed work, but only with both pickups engaged.

    The reality with all hum cancelling strategies is there is a pay-off. The Gibson P100 is a humbucker in a P90 form. It sounds 'like' a P90, but it's not quite the same sound. Similarly, you can add a dummy coil into the control cavity, but it darkens the guitar's tone slightly.

    It depends what your priorities are as a musician.
     
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  9. Hastings

    Hastings Tele-Meister

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    I am interesting in P90s, but I see from the thread title that the questions are "stupid" so I won't bother reading them.
     
  10. trev333

    trev333 Telefied Ad Free Member

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    I use Warman UK RWRP sets of P90's... quiet as a mouse here through any amp and sound great...:cool:


    Cream top Tele small.jpg
     
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  11. simoncroft

    simoncroft Tele-Meister

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    Well, you obviously did open the thread, so why be silly if the OP worries his question might be regarded as 'stupid'?

    None of us are born knowing this stuff, or learn it at school, so when we don't know the answers, it can make us feel bad. In the pre-internet days, it took me years to work out the basics of how to wire guitars, and what the difference was between two pickups selected on a Strat versus the two coils inside a humbucker.

    If you actually have any questions – as opposed to being a smart alek – you're welcome to ask them.

    Screen Shot 2019-08-20 at 02.13.20.png
     
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  12. bftfender

    bftfender Friend of Leo's

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    my 2019 Gibson LP DC is quiet. man did it record well..has that snarl in the mids ,,
     
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  13. simoncroft

    simoncroft Tele-Meister

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    From a Pickup Primer I wrote for Playmusic magazine in 2011:

    The Gibson P90 is one example of a pickup that uses a plastic bobbin for its coil. A single bar magnet sits beneath the coil. The magnet is attached to a steel bar that is threaded to take the six adjustable pole-pieces. It is these pole-pieces that sense the strings and the volume balance between then can be changed by screwing a pole-piece down to make it quieter, or up to make it louder.

    When it was launched in 1946, the P90 was the first pickup to sport adjustable pole-pieces. Back then, a wound third string was standard. A wound string generates a lot more energy than an unwound, so when unwound third strings started to appear in the 1960s during the Blues Boom, there were probably a lot of guitarists taking screwdrivers to their P90s to get some more volume from the G string.

    Both the P90 and most Fender pickups – along with many others – use magnets made from an iron alloy called Alnico (which has added ALuminium NIckle Cobalt). The advantages of this material over steel are that it has a stronger magnetic flux and also stays magnetised for far longer. Nonetheless, even Alnico loses some magnetic power over the years.

    This raises an interesting question when reproducing vintage pickup: do you make the copies sound the way vintage pickups are today, or the way they would have been when they were new?

    Alnico is available with differing magnetic strengths, as indicated by a number after the name. Alnico II generally produces less output but allows for a vintage tone, while Alnico VIII can be used to make high output pickups especially suited to rock styles. Alnico III and V are the most commonly used strengths.


    Science fact:
    The properties of Alnico were first discovered in Japan.

    Ceramic magnets don’t age the same way as Alnicos but opinion is divided over whether the tone is better. Some players describe pickups with ceramic magnets as powerful, sensitive and with enhanced harmonics. Others find them harsh-sounding.

    (It’s worth mentioning that ceramic magnets are commonly used in active pickups, so it’s easy to be confused about what are ‘ceramic’ characteristics and what are ‘active’ characteristics in a pickups sound.)
     
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  14. rangercaster

    rangercaster Poster Extraordinaire

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    The P90 was the original PU for the Les Paul ...
    Still the best choice ...
    Noiseless design single coils as an option ???
    Not for me ...
    The noise is part of the sound... mojo ... mystique ...
    Hendrix, Roy Buchanan, Dick Dale ...
     
  15. Golem

    Golem Tele-Holic

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    There are some options to reduce noise such as using the hum debugger, or the ISP decimator. Kinman makes some great noiseless P90s. You’re not alone in liking the tone but not the hum.


    Sent from my iPhone using Tapatalk
     
  16. bftfender

    bftfender Friend of Leo's

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    thanks, nice post. always wondered about the magnetism..just how long it lasts...if we chasing tone from back when..and back when is now not as strong,,,makes it quite the mission
     
  17. TRexF16

    TRexF16 Friend of Leo's Vendor Member

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    Just to point out though that this picture only illustrates one of the two magnets on a P90.
     
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  18. zeedoctour

    zeedoctour Tele-Meister

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    Yeah it would be a mistake to assume a P90 has one magnet. It has two. One coil, but 2 magnets.
     
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  19. sothoth

    sothoth Tele-Holic Platinum Supporter

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    Yup. And the screw looks weird, too :)
     
  20. simoncroft

    simoncroft Tele-Meister

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    Sorry. My bad, as the kids say.:rolleyes:

    p905.jpeg
     
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