Pickups: The Step Coil

The Step CoilThe Step Coil

Pickup building video #8, Spring 2009, 3 min 55 sec, 59.3 MB flash video

small-screen version available on YouTube

complete “pickups for the electric hammered dulcimer” series on a YouTube Playlist

When I first began, I researched everything I could find on guitar pickups, trying to see if I needed to deviate from standard guitar specs to compensate for making pickups 6 times as long, with 6 times the wire, as standards guitar pickups. Nothing I could find helped. There were a lot of unanswered questions, but I had decided I couldn’t wait, I had to just start making coils and accept using experimental error to answer my questions, even if it meant sacrificing a lot of coils and wire along the way.

One primary question was how many turns, or winds, to use on a coil. To answer this question, I designed a “step coil”. I wound a coil, stopping the machine every 1000 winds and pulling out a loop, labeling it and taping it to the outside, then continuing on, step by step, to 10,000 turns. I would build a pickup where I could use jumpers to “step” from 1K to 10K turns and find the optimal response.

This coil would show me a range, a response curve, were a got the widest frequency response. I refrain from saying “best” because though it is technically the “best response”, it is really the “optimal response” because you can generally remove frequencies better than add what isn’t there. Still, tone is a matter of opinion, and guitar pickups are made over a pretty wide range of specs within a general response curve, creating pickups with different tones. But there is a still a general range that they use, and that is what I needed to find, not a “best”, but an optimal range I could work within.

I could also configure the step coil as two coils, each from 1K to 5K, allowing me to switch between series (combine the number of winds) and parallel (combine the volume), or set parallel coils out of phase, either for noise cancelling (“humbuckers”) or to create phase effects. That is another set of experiments I didn’t get into here. I just needed to answer the primary question so I could continue winding coils, knowing what range I had to work within.

I also made this video because, though the step coil is an integral part of the story, I didn’t need to explain it in detail in the other videos of the series. I would have ended up either cutting this story too short, when it is an interesting story, or having to make the other general pickup building video too long. So I mentioned it in passing, and made this video to tell the full story.

As I worked with the step coil, I wondered about the possibility of using a coil like this for working coils. Though you can create different tones with onboard controls, they are fairly simple, just controlling the volume of a range of frequencies past a set cutoff point. Though ten steps might be more than needed, a step coil might give me access to a wider range of basic tones than just a simple tone knob would, and there are guitar coils based on this idea, though not with so many steps, usually just one. On guitars, it is the mounting position of the pickups that changes the tone of the pickups, usually not actually different pickups. With the dulcimer, though, there aren’t as many places I can mount a pickup, so a step coil might be the equivalent of mounting multiple pickups on a guitar.

Though I answered the primary question, using my spectrograph to find the optimal response curve, I still have more tests and experiments I can run with the step coil, and more possibilities to try and play with as I develop pickups for the dulcimer. The world has had decades and thousands of people contribute to developing guitar pickups. I am one very poor folksinger doing what I can, while trying to do a lot of other things, as well as just survive. But I am doing it, that I am.

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