Winding my own DIY guitar pickups

[zebra50]

Hi!

As some of you might have noticed, I recently acquired a nice Meteor coil winder from another forum member. As part of my learning curve, I am DIY-ing a pair of P90 guitar pickups and I though I would share the fun.

Pickups seemed like a good place to start as they only require a single wind, and all the parts - bobbins, magents and wire are easily available. I've always been a fan of the P90 sound, and they seemed simpler than a humbucker for a first try.

Here's the first one on the Meteor winder...

The winder itself is old - probably 1980s -  but very well built. It has both a cam and a motorised lateral arm for the side-to-side action, as well as the essential counter and wire tensioner.

With a little practice I got 7000 turns of 42 AWG wire onto the bobbin, with a bit of room to spare.

This one measured at about 6K ohms, and my second attempt gave me 8500 turns and around 7K5 ohms. The trick is keeping the tension in the system without snapping the wire! In the end this simply comes down to practice and getting to know the system. They should make a good neck and bridge pair.

I mounted some alnico magnets to the back by gluing them to a scrap steel bar, which I had drilled and tapped for the pole screws...

And here's the finished neck pickup mounted in a guitar for testing.

I was just happy to make something that worked, but in fact I was surprised how good it sounds! Quite a warm rich jazzy tone, that cleans up nicely when the volume is rolled back. The output level is pretty close to the pickup that I removed.

Next job is to wax pot them!

Stewart

 

[abechap024]

Very cool. P90s have always been my favorite, very raw tone. That machine looks like it is built like a tank! I like!

 

[zebra50]

It is indeed built like a tank. Here's a shot inside...

It's quite interesting actually. As well as adjustable belts for the motor speed, the two conical plates that look like Madonna's chest (!) are an infinitely variable gear train that sets the lateral motion to the wire gauge. The big knob on the front panel (far right) turns a friction wheel to transfer the drive.

There is a foot pedal for start, stop and speed too.

The whole thing runs up to about 18000 rpm, but I'm going lot slower than that!

 

[Rossi]

Very nice! I like the fact that your P90 is a bit underwound; most normal or overwound P90 pickups sound too dark to me.

I did some pickup winding quite a while ago, rewinding a Fender Mustang single coil and building a humbucking Jazz Bass pickup. My gear was pretty laughable; I didn't even have a counter - it was all guesswork. The pickups sounded fine, though, and I still use them.

 

[zebra50]

Hi Rossi,
I ended up a little underwound because I was being conservative in terms of tension and how many turns I could fit. But they do sound nice. I should overwind one for comparison.

There's something in pickup mythology that I don't quite understand...

Why should different magnets give different tones?
I understand that different magnetic fields strengths will give different output levels.
Is it simply the 'saturation' characteristics, in a similar way to transformer lams becoming saturated?

I think I just answered my own question.

 

[Rossi]

Just measure the inductance, and you'll know. Just like a transformer core, different materials (and construction) will give different inductance. For instance I took a cheapo chinese single coil, took out the iron pole pieces and the ceramic magnet underneath, and put in ALNICO magnets (reed magnets aobut the same size as Fender single coil magenets). The inductance became much lower and the tone cleared up a lot.

By the way, I devised a setup to measure the frequency response of guitar pickups. One thing that surprised me is that the measured response looks almost identical to a circuit simulation (knowing the RCL parameters of the pickup). So most of it is just physics. But there is some mojo component, that hard to put in numbers.

 

[zebra50]

Good to know the physics is working!
Did you model the pickup as inductance and resistance in series, with winding capacitance in parallel?

Edit: Looks interesting!
http://terrydownsmusic.com/technotes/guitarcables/guitarcables.htm

And: Here's a good page on measuring pickup response.
http://buildyourguitar.com/resources/lemme/

I may just have to wind myself a transmitting coil!

 

[Ptownkid]

Cool Beans! One of my favourite guitars is a $400 Godin with p90's...

 

[Rossi]

That article is written by Helmuth Lemme, a German guy who wrote the book that introduced me to guitar electronics in the early 80s. I don't agree with everything he writes, but his calculations are excellent.

Here's my strat simulation. I usually simulate with all the external factors such as controls, cable capacitance and amp input impedance. That's how you hear your guitar.

The numbers manufacturers give you of the pickup alone are misleading. The resonant frequency of a "naked" Strat single coil is about 10k, but you hear it around 4k due to external factors.

One thing I disagree with Lemme is that a strong resonance means superior sound. A resonance of 3-6 dB (external factors included!) is what sounds best to me. I actually soldered resistors across the output jack on occasion in order to tame the pickpup resonance.

 

[Rossi]

...and here's the simulated response. I can't find my actual measurements of a Seymour Duncan Vintage Strat set right now, but it looked very similar. No ripple, just a clean smooth line.

 

[12afael]

this is the PRO part of the forum, you didn't wind it by hand and also you have a responce curve.

My setup, with a drill and an old calculator, to wind transfomer look like nothing beside this.
congratulations

cheers
Rafael

 

[zebra50]

Yes, everything is getting all too professional here!

We need to get back to botching and improvising.

 

[Rossi]

In my case, the measurements may have been professional, but my winding gear was anything but. It was literally toy-stuff (Fischertechnik) and had no counter. Also, I used regular wire from an electronics store (0.01 mm), not the good stuff. The bobbins were hand-sawn and drilled (with little precision). The magnets were regular reed relais magnets, no magic bullets from days of yore. Still it worked. The humbucking Jazz Bass PU I built is still a favorite.

A real winding machine like Stewart's is certainly a big plus, but if you feel like winding your own pickups, you can do it with whatever you have. I wonder why not more people experiment with pickup winding. It's actually pretty hard to screw up. I can't think of a way to wind copper around a magnet without getting something that picks up a metal string.