Do Different Pole Piece Shapes and Sizes Impact Tone?

Discussion in 'Pickups & Electronics [BG]' started by FugaziBomb, Aug 30, 2017.


  1. FugaziBomb

    FugaziBomb

    Jun 5, 2017
    I saw an ad for the Nordstrand power blades on the TB front page, with their unique staple-style poles and that got me thinking about Delanos and SD Quarter Pounds each also touting their enhanced pole piece sizes, but to what end? I did a quick search, but I didn't see a lot of talk on the topic. Is it mostly sales hype, or is there a significant difference between two similarly designed pickups with different pole pieces?
     
    Peter Torning likes this.
  2. This is one of the key factors in determining what a pickup sounds like. The shape of the magnetic field and the way in which the strings disturb it when they vibrate is part of what makes pickups sound different from each other.
     
  3. lz4005

    lz4005

    Oct 22, 2013
    Particularly if your definition of tone includes the attack envelope (which it should).

    As one example, Fender's original single coil P bass pickups had one big magnet per string. Their later split coil P pickups and Jazz pickups have two smaller magnets per string.
    The one-per design produced a stronger attack that was blowing speakers in Fender's bass amps in the 50's.
    The two-per produced the same volume level, but lessened the attack a little.
     
  4. bolophonic

    bolophonic

    Dec 10, 2009
    Durham, NC
    I'm intrigued by this subject. I have decent quality pickups in all of my basses, but I couldn't tell you anything about how any of them are constructed or how the manufacturing methods factor into it.
     
  5. FugaziBomb

    FugaziBomb

    Jun 5, 2017
    Kind of the same principle with EBMM's Old Smoothie... Ok, interesting. I really never thought of pick-up design paramters in terms of magnetic fields and attack envelopes - just lows, mids and highs.
     
  6. lz4005

    lz4005

    Oct 22, 2013
    Exactly like the Old Smoothie, in terms of how the string passes by the magnet poles when you release it for each note.

    Tone includes both EQ and attack/sustain/release. You don't get the full picture without both.
     
    monsterthompson likes this.
  7. FugaziBomb

    FugaziBomb

    Jun 5, 2017
    I feel like I just took the red pill.
     
    BlueTalon and lz4005 like this.
  8. Bassamatic

    Bassamatic keepin' the beat since the 60's

    Yes, it does. My genius engineer who knows everything about instrument electronics modified a pickup once to use larger screws with bigger heads for the pole pieces and it changed the sound a LOT.
     
    FugaziBomb likes this.
  9. road-cat1

    road-cat1 Supporting Member

    Mar 24, 2008
    Mesa, AZ
    like the SUHR designed Jazz Bass pickups during his time at Fender.....did anyone ever compare the sound of his pickup designed (single pole per string) with the more traditional Fender dual pole per string?
     
  10. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    I've found that I like the sound of bigger pole pieces with ceramic magnets.

    3PU1C4361.jpg

    Blade pickups are pretty great as well:

    BeD-UEjCUAA7Idx.jpg
     
  11. sikamikanico

    sikamikanico

    Mar 17, 2004
    I think I hear differences, but find it hard to attribute anything to poles specifically. Typically, other things are also different. E.g. MusicMan or G&L pickups don't only have larger pole pieces, but also that characteristic wide humbucker design. But then MM is an underwound alnico designed for a preamp, while G&Ls are more muscular and with ceramic magnets...

    But say a P pickup, compared to another one with alnico 3/8 poles (like M&V Atlas), and I find it that they have more in common than not. Variants of the P sound. The M&V Atlas kind of reminded me of DiMarzio Model Ps, which has similar poles than your typical P (but use ceramic magnets).
     
  12. Bruce Johnson

    Bruce Johnson Gold Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    In the design of a pickup, there are four main factors which determine the overall sound and response:

    1. The strength of the magnetic field created by the pickup.
    2. The shape of the magnetic field; how it surrounds the string, and how it surrounds the coil.
    3. The geometric shape of the coil, how it fits in with the shape of the magnetic field, and how densely packed its wire turns are.
    4. The electrical characteristics of the coil, which can be divided into:
    • The number of turns of wire
    • The impedance of the coil, which can be approximately measured by the DC resistance of the coil.
    And of course, pickups with multiple coils can be wired in series, parallel, and humbucking.

    The shape and look of the pole pieces (or blades or whatever) primarily affect #2. What you see as pole pieces are often the magnets themselves. Or, in some designs, the magnets are buried down inside and iron blades, rods or screws are used to extend and shape the magnetic field, coming from the magnets themselves. There are many different designs out there.

    But that's what it's all about: shaping how the magnet field surrounds the strings and the coils. And there isn't any single "best" way, or fixed definition of how a pole piece design will sound. Because the other factors all participate in the sound too.
     
    TomB, BlueTalon and 4StringTheorist like this.
  13. Stonetown Lows

    Stonetown Lows Commercial User

    Jan 23, 2014
    Warwick NY
    Owner, M&V Guitars &Pickups
    Amen, Mr. J. All just recipe factors in designing a pickup. There is no "best" design, and you can usually offset one aspect by changing others, within usable limits of course!
     
  14. JW56789

    JW56789 Guest

    Feb 18, 2017
    Another thing about 'blade' pickups: You NEVER get any feedback that 'my strings don't line up over the pole pieces' !
     
  15. Sean Sweeney

    Sean Sweeney

    Mar 23, 2021
    Hey there! First post on here... I was curious... or I was under the impression that the double pole jazz bass pickups have alternating north/south magnets, in a sort of "push pull" setup to avoid phase cancellation... now I could be wrong... and if I AM... why hasn't anyone done such a thing for bass? It would be crazy to not use a push pull amp for high wattage bass... I was under the impression that the pole pieces were alternating... and it makes sense on something like a bass... yet I haven't heard anyone mention it here or elsewhere... I am just wondering if I'm crazy, mistaken or a GENIUS... lol And I've been thinking about using that idea for guitar... with instead of 6 pole pieces, having 11... just because on the neck pickup the poles are always an issue... if you bend a note you can feel the note get colder the more you stray from the pole piece... but if you had two small poles for each string... it would catch everything and you could stray off the pole and still have your note hot... and I'm sure i'll make a prototype and discover all the reasons why this hasn't been done... but as of now, I'm having trouble visualizing a down side!
     
  16. All the pole pieces (magnets) would have the same polarity in one pickup, but opposite polarity to the other pickup. For example, Bridge pickup magnets have North Pole facing the strings, Neck pickup magnets have South Pole facing the strings.
    I could only assume that if there were alternating poles in one pickup, it would create havoc in the magnetic field...I don’t even know what would happen.
    Anyone want to try?
     
  17. Sean Sweeney

    Sean Sweeney

    Mar 23, 2021
    well, definitely I would imagine it working better on a bass than a guitar... I'm just envisioning a push pull relationship like a standard amp has... maybe use a horseshoe magnet like the early Rickenbacker frying pan did... have one polarity below and one polarity above, with the horseshoe magner encircling the pickup... or maybe not! lol... I forgot about the magnetic field part and the opposing forces... but I could try it with a simple pair of alnico poles... and see how that works... if you had one above and one below, maybe... hmm... forgot about that part of the equation... I wonder if there is anything besides a magnetic pickup that could sense the movement of ferrous strings? I mean... active pickups do that, correct? sheesh... I gotta think this one through now...
     
  18. dwizum

    dwizum

    Dec 21, 2018
    Pickup polarity and amp topology are very different concepts - the "push pull" amp design you're talking about doesn't really translate to the polarity of the magnetic poles in a pickup.

    The polarity of the magnets determines the direction of the current in the windings. But the relationship in polarity among the poles on a given magnet also have a heavy influence on the shape and strength of the magnetic field. When designing a pickup, our goal is to "project" the field up towards the strings so they can be sensed. It's easy to mess that up when you start doing things like including north-up and south-up magnets or poles in close proximity in a single pickup. When nearby poles are all oriented the same way, the field lines tend to point straight up, away from the poles. When you have opposite poles near each other, the field lines tend to point straight from one pole to the other, and - depending on the overall arrangement - you sort of "miss" the strings.

    There are some pickups where polarity isn't uniform. Notably, most humbuckers built with two coils next to each other (as in a typical PAF style guitar humbucker) have one coil with north up and one with south up. The design of the pickup tends to cast a wide magnetic field and still catches enough of the string to work well. That wide field is a big reason why humbuckers sound they way they do, compared to a single coil with a narrower field. If you look at a PAF design in a magnetic field simulator, it shows a really interesting field shape. If you do a cross section that's on the same plane as a given string, you find that - up where the strings are - towards the neck end of the pickup the field is strong. Then it gets very weak in the middle of the pickup, and stronger again on the bridge end. The design is basically sensing two areas of the string, just above and just below the two rows of pole pieces.

    Another common design that uses both polarities in a single pickup is a split-coil Jazz pickup. These feature two smaller coils in line with each other stuffed into a normal jazz shell. Each coil senses two strings. The two coils typically have opposite magnetic polarities so they they are hum cancelling (when wired together with reversed wind directions as well). Split coil jazz pickups often have a dead zone right in the middle. If you put the design in a magnetic field simulator, you can see why - in that area between the two coils, the field lines are really strong down inside the pickup, but weak in that narrow swath up where the strings are. If you built a pickup with two poles per string and had the polarities of the two poles alternating, you'd basically be building a mini version of that dead zone directly in line with each string.

    Your goal of having a sensing range that extends wider past the outside strings isn't a bad idea though. But there are good ways to do this besides putting two opposite polarity coils right next to each other. For instance, put two same-polarity poles next to each other! Like Leo did with J and P pickups. This gives you a wider field (side to side) AND a field that projects up towards the strings better. It's really the ideal design, compared to a typical guitar humbucker with a single pole right below each string.

    A pickup with more poles than strings, and poles spaced more widely than the strings, has been done from time to time. Bill Lawrence did it with some of the Wilde pickups.
     
    TomB likes this.
  19. dwizum

    dwizum

    Dec 21, 2018
    An active pickup is just a passive pickup that's had a preamp stuck inside the case. The actual sensing part of the pickup is exactly the same - nothing more than a magnet and a coil of wire (and sometimes some steel to help direct the magnetic field).
     
  20. FugaziBomb

    FugaziBomb

    Jun 5, 2017
    I like how this thread popped back up again after 3-1/2 years like it's the latest season of Curb Your Enthusiasm.
     
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    Primary TB Assistant

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