1. Welcome to TalkBass, the Premier Bass Player Community and Information Source. We've been uniting the Low End Since 1998!

    We're glad you've found us. Register a 100% Free Account to post and unlock tons of features.

Reverse wound pickups-why do I need them?

Discussion in 'Pickups & Electronics [BG]' started by Mike Sorr, Feb 25, 2014.


  1. Mike Sorr

    Mike Sorr Hack with nice gear. Supporting Member

    Joined:
    Oct 24, 2012
    Location:
    Exit 82, NJ
    I have a Carvin B50 bass with their H50A pickups in it. If I keep the bass I'm considering switching to Carvin's more aggressive J99A pickups as I'm playing a different style of music these days than I was when I first got the bass. When it comes to gear, I'm a driver not a mechanic, so I have no idea about electronics, wiring or what goes better with what (apologies for my technical ignorance, I've been a Jazz and P Bass player for 30 years). So when it was recently suggested that I get the reverse wound version of these pickups I had questions. Their J99AR-2 are hotter than the H50A, but supposedly the reverse magnet will still keep them quieter than the standard J99A. The price for both versions of the J99A is the same.

    So, a few questions: Do I want the reverse wound pickups or are the standard pickups fine and why? On a Jazz style bass I usually run both volumes full on...wouldn't that cancel out noise anyway? Also, the bass is currently completely passive. Do I want to add a preamp? Why?

    http://www.carvinguitars.com/group/bass_pickups
     
  2. MostlyBass

    MostlyBass Supporting Member

    Joined:
    Mar 3, 2002
    Location:
    Oak Park, IL
    I believe you want one of each. A regular wound with the reverse wound is what does the canceling.
     
  3. Chainsaw Willie

    Chainsaw Willie

    Joined:
    Nov 6, 2011
    Location:
    Redmond, Washington
    Only ONE pickup of a pair should be reverse wound with reverse polarity magnets. Thats what makes it cancel hum when used both pickups on.

    Two pickups with the same wind/polarity will not cancel hum.
     
  4. wideload

    wideload

    Joined:
    Apr 15, 2004
    I'm in the same boat as you, man. Don't reverse wound pickups suck notes out of your strings? :)
     
  5. Register to disable this ad
  6. BlueTalon

    BlueTalon Happy Cynic Supporting Member

    Joined:
    Mar 20, 2011
    Location:
    Spokane, Washington
    Disclosures:
    Endorsing Artist: Turnstyle Switch
    I like passive personally, so I would not put a preamp in. But that's just me.

    Is the bass you are talking about the one in your avatar? If I understand you correctly, you currently have to H50A, and you want to swap them both out, right?

    Just be sure you get one J99A and one J99AR. The reverse winding on the J99AR will help eliminate noise, but only when used in conjunction with the J99A. Using two of either type of pickup will not cancel any hum at all.
     
  7. Mike Sorr

    Mike Sorr Hack with nice gear. Supporting Member

    Joined:
    Oct 24, 2012
    Location:
    Exit 82, NJ
    Yeah, that's the one. If I can't move it, I'm going to switch the pickups out. The H50As are great for that roots tone I was going for when I got it, but these days I'm doing more of a rock thing and would rather have hotter pickups.
     
  8. Mike Sorr

    Mike Sorr Hack with nice gear. Supporting Member

    Joined:
    Oct 24, 2012
    Location:
    Exit 82, NJ
    What kind of bass is that in your avatar Bluetalon? That is a very cool and interesting looking instrument.
     
  9. BlueTalon

    BlueTalon Happy Cynic Supporting Member

    Joined:
    Mar 20, 2011
    Location:
    Spokane, Washington
    Disclosures:
    Endorsing Artist: Turnstyle Switch
    Glad you like it! It's a Warmoth Jazz build. If you want to read about it and see better pictures, go here.
     
  10. line6man

    line6man

    Joined:
    Jun 20, 2008
    Location:
    Close to Los Angeles, CA
    In order for an even number of coils to humcancel, they must be RWRP. That means that they are wound in opposite directions, but the magnets are flipped, as well, so that the signals remain in phase, but any 60Hz hum induced in the coils is out of phase, to cancel itself out.

    As stated above, you don't want pairs of pickups in the same orientation. If you want to humcancel, one must be "forward," and the other must be "reverse."
     
  11. Dogghouse

    Dogghouse

    Joined:
    Jan 25, 2011
    Location:
    Santa Barbara
    Disclosures:
    Bass Guy @ Seymour Duncan
    It doesn't suck the tone out of the pickup. This whole issue only pertains to single coil pickups by the way. One can have passive pickups and still add an active circuit which will provide true EQ capabilities of plus or minus db's of bass, mid's and treble.
     
  12. uOpt

    uOpt Supporting Member

    Joined:
    Jul 21, 2008
    Location:
    Boston, MA, USA
    You never need reverse wind (reverse electric phase).

    For hum-canceling you must have reverse polarity (that is magnetic polarity) and then you can just switch the wires until the bass sound is in phase and the hum is not (canceled).

    It generally looks better to have reverse wind. And of course if you have a baseplate or other mass involved then reversing the wires will usually mean that you have to re-solder the plate to the other side. So the devil is a bit in the details.

    Stratocaster players debate whether the presence of a reverse polarity pickup in the middle changes the sound, in some variants of when two pickups are on, or when just one pickup is on. Or whether hum-canceling is for sissies in the first place.
     
  13. BlueTalon

    BlueTalon Happy Cynic Supporting Member

    Joined:
    Mar 20, 2011
    Location:
    Spokane, Washington
    Disclosures:
    Endorsing Artist: Turnstyle Switch
    My guitar playing best friend thinks that. He's an idiot though.
     
  14. RobbieK

    RobbieK

    Joined:
    Jun 14, 2003
    +1. RW not so important, it's the RP that makes the hum go away. IOW, it's ok to have two singles from different makers so long as the tops of the pickups attract.

    There is one place however where RW is not a bad idea, and that's where the magnets are exposed and also unearthed, ie vintage fender style pickups. This is so you can have the inner windings of both pickups at earth potential so the pickups don't hum when you brush the tops of the magnets with your fingers or thumb. Like most fingerstyle players, my thumb rests on the E string a lot and it touches the magnets here.
     
  15. RobbieK

    RobbieK

    Joined:
    Jun 14, 2003
    Ha! that's great... I often wonder why they didn't make mains power oscillate at 10 or even 20Hz. Our life would be a lot easier. And the internet wouldn't be clogged up with such important discussions such as whether strat pickups should hum or not...

    Actually I'd love to know when exactly Fender officially started puting RWRP pickups into strats teles and jazz basses. I've asked on a few fender forums with no luck. I've heard of people spending big $$ on "original 70's matched pair jazz bass pickups" but not getting RP... :confused:
     
  16. uOpt

    uOpt Supporting Member

    Joined:
    Jul 21, 2008
    Location:
    Boston, MA, USA
    Are you saying that the magnet rods really electrically connected to inner coil wire?

    Or that they are not and you induce noise into the side of the wire that goes on the inside of the wind?
     
  17. RobbieK

    RobbieK

    Joined:
    Jun 14, 2003
    Actually they shouldn't be, but with vintage fender pickups they often are because they wound straight onto the magnets with out wrapping insulation tape first, and the alnico corrodes plus the winding wire only has a very fine coating of insulation, plus the original wire only had shellac or something as insulation. These days winding wire has a fairly tough and flexible poly coating of some sort. A short at the magnets is not ideal, but IME a vintage fender pickup can work just fine for years this way.

    No matter which way the coil is phased, you can earth the magnets pretty easily with some copper tape that has conductive adhesive (ebay), and that will stop them from buzzing when touched. But of course an old fender pickup with a short to the mags will be silent if the outer windings are at earth and then you go ahead and earth the mags.

    well, yeah that's pretty much what's happening.

    FWIW, if your coils are in series, like a P pickup, you'll notice one will buzz more than the other. And even if one coil is phased with the inner windings at zero volts and is silent when touched, the other has it's inner windings half way between earth and hot, so will always hum a little. For this reason I like to know the playing style/hand position of the player so I can make the coil that he/she is most likely to touch while playing the no hum one. (If that doesn't sound like double dutch!)
     
  18. uOpt

    uOpt Supporting Member

    Joined:
    Jul 21, 2008
    Location:
    Boston, MA, USA
    That's a great piece in the puzzle. Thanks for sharing.

    Another thing that I was thinking about is, for single coil pickups like a Jazz, whether there is more hum when the wire that end up facing ground starts inside the coil. If the outside of the coil is the end that goes to ground next, wouldn't the outer layers shield the inner layers a little bit?
     
  19. RobbieK

    RobbieK

    Joined:
    Jun 14, 2003
    Yeah, a very small amount I guess, but pickups "pick up" mostly from the top. (That's why they put the strings there :D)
     
  20. bassbenj

    bassbenj

    Joined:
    Aug 11, 2009
    Yes it does but that part of the coil is usually down inside a rout so you don't get near it. But the question about are the magnets connected to the inner wires of the coil hits the nail on the head. While they CAN get actually connected if the insulation gets damaged (as in Fender pickups with the wire wound right on the magnets with no extra insulation) you might think there is no connection. But that is wrong. And this is because the inner coil and the magnets form a CAPACITOR and that cap is like a volume bleed cap so when you touch the magnets the hum from your body goes right into the center of the coil which if wired reversed will be the hot end so it goes right into your signal. This is why you want your second humbucking pickup to have both reveresed magnets AND reverse wound coil. That keeps ground at the center of the coil and THEN as you note the layers of grounded wire actually shield the REST of the coil from the him coming in on the magnets! If you just use reveresed magnets and only reverese the wires on a forward wound coil the center is hot and that's how hum gets in down the magnets.

    Now some ground the magnets to solve the problem and it does. However, remember that capacitor between the magnets and the inner coil. Depending on how tight that is wound and how much insulation there, this can have enough capacitance to begin to act like a tone control shunting signal if the magnets are grounded. Now if the coil is reversed wound the center is ground so there is no tone effect from the capacitance. Thus a reverse wound coil plus grounded magnets is like belt and suspenders when it comes to induced hum in the pickup.

    Of course if you do all this the OUTSIDE of the coils are not hot and can pickup up hum. So some makers put copper foil around the coil. But again if the foil is too close it gives too much capactance and affects the tone. That's why I prefer unshielded coil but copper lined routs for pickups. That helps keep the foil away from the coils and keeps tone roll-off to a minimum.

    But let's face it. Only sissies worry about single coil hum.... ;)
     
  21. uOpt

    uOpt Supporting Member

    Joined:
    Jul 21, 2008
    Location:
    Boston, MA, USA
    That is for magnetic inductance, aka from the strings.

    The noise doesn't need and doesn't use the magnets.

    (that is why you can cancel hum with a blind coil with no magnets)
     

Share This Page