Welcome to the final article about guitar pickup design. In the previous articles we covered magnets and coils. In this article we shall discuss other components and how they affect the sound produced by guitar pickups.

Bobbins

All pickups have bobbins. The coils are formed onto the bobbins, plus they hold the pole pieces in position. Traditionally single coil bobbins were made of compressed fiberboard and many still are. Bobbins using fiberboard have a top and bottom plate and are pressed onto the pole pieces which act as an integral part of the bobbin structure. The magnet wire is wound directly around the row of pole pieces and held in place by the fiberboard plates.

Humbucker bobbins were originally made of butyrate; a type of plastic available during the 50’s when they were first in production.  Modern plastics are used these days for humbucker bobbins, and also for many single coil bobbins. The choice of materials for bobbins all have one thing thing in common: They are not made of metal and the materials used have no influence on the magnetic field, induced voltage or the tone produced by the pickup. Bobbins are simply there to hold the pole pieces and coil in place. Some still insist on using butyrate for humbuckers believing it will make the pickups sound more authentic, but it doesn’t.

Plastic bobbins for single coils have one major difference to fiberboard bobbins. In plastic bobbins the pole pieces slot into a sleeve joining the top and bottom of the bobbin. This means that there is always going to be a small gap between the coil and the pole pieces. It does have the ability to change the tone of the pickup, but with pickups having so many tone changing variables, but the difference in tone is negligible.

Base Plates

Some pickups have metal baseplates. Humbucker base plates are usually made from either nickel silver or brass. Nickel silver is the preferred choice in most instances, but brass is used in many budget pickups and some more expensive ones. Choice of base plate material will affect the tone if it is made of metal. Any metal within the magnetic field of a pickup will have an influence on that magnetic field, and will itself induce small electrical currents known as eddy currents. Nickel silver is less conducive to eddy currents and is the first choice for that reason. Brass baseplates have a tendency to darken the tone more than nickel silver, but that could be a good reason to use brass if that is the effect you are looking for.

Fender Telecaster pickups often have copper plated steel for baseplates. This also will darken the tone, but the end result sounds good and helps to give the telecaster it’s unique voice.

Covers

All pickups were originally designed to have covers. The plastic variety have no impact on the pickup’s tone, but the metal ones do. Nickel silver is the preferred option again for the same reasons. Eddy currents have their part to play again here. Some prefer the tone of a pickup with a cover while others prefer a more open sound and either remove them or buy them with no cover. It’s a matter of personal choice.

Slugs and Adjustable Pole Pieces

Humbuckers use steel slugs in one coil and steel adjustable pole pieces in the other. P90 pickups also use adjustable pole pieces in a similar arrangement. Slugs and adjustable poles are used instead of alnico pole pieces. Pickups of this variety utilize a bar magnet inside the pickup. Due to their proximity to the bar magnet, slugs and pole screws extend the magnetic field out of the top of the pickup in a similar way to alnico pole pieces.

The rest

We have covered all the parts for most single coils. Other parts in humbucker pickups include steel keeper bars, baseplate screws, lead wires, and spacers. Any metal parts will have some sort of effect on the tone, and while choosing brass baseplate screws over steel ones might seem wise to some, in reality any difference is indistinguishable. Nonmetal parts can be made of any material, as long as the dimensions don’t change, the tone won’t change. I have even heard one boutique pickup manufacturer suggest that their PAF reproduction pickups achieve authentic vintage PAF tones because they use spacers made with West Michigan Maple. If those spacers were made of cheddar cheese, those pickups would sound the same.

Conclusion

Vintage correct materials and manufacturing techniques are not essential for good tone. Certainly, the use of vintage style cloth insulation on hookup wires doesn’t improve tone but, it’s nice to work with. In addition, there is no justification for claiming that all vintage things were good, and all new things are inferior. The idea that no-one has learned anything in fifty years is foolish. Many of the vintage styled pickups available today are vastly superior to the majority of genuine vintage pickups and they can be expected to be consistent as well. Vintage pickups were mainly characterized by variability and that equals inconsistency in quality. While good and bad tone are subjective judgements, there is no possible argument for claiming that random variations produced consistently good results, and that consistent design and manufacturing produces consistently bad results.

At the end of the day if it sounds good to you, then it is good enough. Some really cheap pickups can sound great but it’s a gamble, medium priced pickups should be expected to sound great no matter what. Premium priced pickups are simply too expensive and don’t sound any better. Spend $10,000 on a genuine pair of 1959 PAF pickups and one thing is certain. You are going to convince yourself they sound amazing to justify the expense even if they don’t, that is until that 60-year-old coil insulation starts to break down of course.

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6 Responses

  1. Awesome blog, I’m glad I stumbled upon it. I am a guitar maker and I have been contemplating winding a range of my own baseline pickups, hunbuckers, p90s, single coil and tele. I don’t want to reinvent the wheel and mostly thought the undertaking would be to get a decent quality product at a decent price as most people buying custom instruments have already made up their mind over what they want in there or buy something and want to change it. However wading through the insane amount of BS and misinformation and even trying to discern what is real or not has been a nightmare. I have been on the journey with guitar making for years trying to dispel all the myths of Brazilian rosewood boards and Honduran mahogany being the only wood that can possibly sound good and educating my Customers but then to face it again with pickups was enough to put me off the whole experiment. After reading through this I’m back on board. I’m only interested in plastic bobbin, poly wire and alnico 2 and 5 magnets and I’m just going to keep it simple. I have a homemade winder and tensioner and I’m just going to wind by hand and not get caught up in the hype. Chances are high someone is going to change the pickups anyway no matter how good they sound. It may fail terribly and I end up using someone else’s product but I just wanted to say thanks for the inspiration.

  2. I love your series of articles on designing pickups. Well done. I have a suggestion. I want to begin making my own pickups (for personal use only) by attempting to duplicate a humbucker that is in my Epiphone Sheraton. I measured the DC resistance, inductance, and know it has Alnico 2 magnets from the manufacturers specs. How do I determine the number of turns to wind?
    I figure it’s probably 42 gauge wire. Should I estimate the number of turns by measuring the bobbin dimensions and estimating an average length of a turn? Then the number of turns = DC Resistance divided by the resistance of an average length of a turn. Correct? Or is there a better way?

  3. Will the use of a non copper winding make a difference in tone?…such as fine silver wire…
    Also, what is the smallest wire gauge that will work and how big of a gauge can you go?

    1. Yes all variables such as magnet wire material and wire gauge will affect the tone of a pickup. Silver wire is supposed to sound very open when compared to copper but at $300 dollars per pickup you have to ask does the difference in tone justify the extra cost.

      As for different gauges of magnet wire, the optimal gauge is that which fills a bobbin and creates the most balanced tone. Most manufactures use magnet wire in the 41 to 44 AWG range. 42 AWG is the most commonly used wire, with the thinner 43 gauge wire commonly used in smaller pickups as used in a Telecaster neck position and lipstick pickups. 43 AWG wire is also used in standard sized pickups where more winds are required for more output and use with stronger ceramic magnets. Lace sensors use even smaller gauge wire in order to get the right amount of winds into a smaller space. I wouldn’t recommend using magnet wire larger than 42 AWG in standard pickups because filling the bobbin will leave you with a pickup which will have low output and thin sounding. However, A P90 wound with 41 AWG magnet wire might sound good due to it’s wide bobbin and ability to take more wire.

  4. Thanks very much for the post. Very technical replies!
    I saw an advert/review of the Fender Telecaster 52 Custom Shop reissue on you tube, where the luthier remarked on the neck pickup’s nickel cover which instead of brass give a tone more like a strat. When he played it, it sounded wonderful – that hollow sweet sound was prominent up the neck and even before the 12th fret.
    So I have ordered a set of Tonerider pups which are advertised as having the nickel cover. I trust they’ll do the job.

    1. Hi Neil, Any quality telecaster neck pickup should have a nickel-silver cover. We only use nickel-silver at Octave Doctor for all our tele neck and humbucker covers. Brass covers tend muddy the tone somewhat. They also sound great with the cover completely removed.

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