Today, I started looking at these pickups; what they’re made of and how they’re made. Unfortunately, the pickups on this guitar were not the greatest to start looking at. The single-coil ones had been super-glued together, making it tough for me to take the bottom cover off and impossible to get the top cover off. The humbucker pickup was easier to get apart but still not very easy to get a full look at.
Single coil pickups are fairly easy to understand. They consist of a bar magnet, which acts as a base, wire, pole pieces, and a cover. The wire is wrapped around that base bar magnet thousands of times which allow voltage to flow once a current is generated.
Humbuckers are slightly more complex. The one in this guitar (as well as most other humbuckers that I’m aware of) are made up of two small single-coil pickups mounted on top of another base magnet, surrounded by more pole pieces.
Now, I know a lot of this may sound pretty ridiculous (or maybe it doesn’t), but I will explain it all. For those people who aren’t into physics, this may either just drive you insane or could be an interesting lesson for you. It was originally physics class that got me thinking about guitar pickups and electronics. So, how does each piece of a pickup help make a sound come out?
- Base magnet: creates what is called a flux field around the pickup. What’s cool about fluxes is that I studied them for about a month in physics and I still hardly have the slightest clue as to what they are. I do know however, that they can create an induced voltage and current. Because of Faraday’s Law and Lenz’s Law... I’m just kidding. I won’t actually start teaching the reason the voltage is created because all you need to know is that it can happen. Keep that in mind for later.
- Wire: allows current to flow. When voltage is induced in the flux of the base magnet, it generates a current. With current flowing through the wires, they cause the pole pieces to become electromagnets due to the way they’re wrapped.
- Pole pieces: or electromagnets create a magnetic field. When you play your guitar, the metallic, slightly magnetic strings vibrate with each strum and the vibrations within the magnetic field generate an electric signal. That signal is then transferred through the guitar’s electric circuit, through the cable, into your amp, and out your speakers in the form of glorious music or potentially horrific noise.
So that is how that all works out. Single-coils, again, are pretty simple; one coil wrapped around a pole piece, through in a base magnet and you’re all set. They can achieve great tones, but because there is only one coil, it can give a “hum” noise. Humbuckers use the two single-coil pickups, each wrapped in opposite directions, to cancel out the “hum”. They are unfortunately known to give up some of the tone that a single-coil has in order to cancel that “hum” noise.
Another thing I was unaware of when I first started taking apart my single-coil pickup was the “potting” used on it. First, what is potting?
- Potting – sealing the coils in a solid material. This solid material is often wax and it prevents the coils, magnets, and other pieces of the pickup from moving around, relative to each other. It prevents the pickups from giving feedback by eliminating and vibration-induced signals.[1]
After finally prying off the bottom cover of the pickup (remember all that super-glue stuff I mentioned earlier), I slowly started to scrape off some of the wax, thinking it was excess glue of some sort. I hadn’t paid much attention to the resources I was using so I initially had no idea what the wax was. After realizing it would be fairly impossible to take the whole pickup apart, I decided to find out what this stuff was to find out that it was wax and that it was pretty important. Luckily, wax isn’t very hard to come by and a quick match-and-candle cover job worked wonderfully.
With the new knowledge of pickups I have discovered today, I am definitely interested in making my own and trying things out. It will take a lot of time, probably money too (which I don’t have), but I think it would be a great experience.
Until next time,
-- Mike
[1] http://www.guitarnuts.com/technical/electrical/index.php
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