One topic that intrigued me as a young guitar player was definitely modifying my guitar's electronics. I remember when I bought the harness for the "Jimmy Page" wiring. That was absolutely crazy—four push-pull pots doing SOMETHING. I was so happy to have so many sound combinations that I forgot to practice. Anyway, very soon I’d remove two faulty push-pulls and gradually revert to the old-school style of having no mods on a Les Paul and just focusing on playing. But it was so cool to explore that.
Now that I've expressed some feelings about memories long forgotten, I’d like to start the topic of parallel coils. So, what am I talking about here?
Jumping back into the memory of the Jimmy Page wiring, I clearly remember that two of the push-pull pots were wired to achieve a split-coil. Obviously, after switching from a Telecaster to a Gibson Les Paul, a thought was planted in my mind that I needed some single coils for my gigs. So, I gave those splits a try. And to be honest, I didn’t like them. I still don’t really like them. I will say that there are some humbuckers that sound good when split, but most of the vintage-style PAFs I usually play don’t sound that great when split.
After hours and hours of surfing forums and the internet, I came across this topic of coils in parallel. Apparently, there was another way to get this "brighter" and "thinner" sound that somewhat resembled the split coil. Also, apparently, there was a huge benefit to this new system—it didn’t hum!
Obviously, I had to give it a try! But before I share any subjective comments on the sound achieved, let’s dive in and explain what the parallel coil connection is all about.
Okay, most of us are familiar with how the humbucker works, right? There are two coils of wire, sometimes one next to the other (like the PAF), sometimes one above the other (like some single-coil sized humbuckers), and these two coils of wire are connected. Normally, in 99% of the pickups we use today, the connection between the two coils is done in series. That means that the end of one coil is connected to the beginning of the other coil, and we use the two "outer" wires to connect the pickup to the rest of the guitar's electronics.
To achieve the "correct" sound of a humbucker, it is mandatory that the magnets, or slugs, around which the coils are wound are of reversed polarity. Not only that, but in addition to being magnetically reversed, the two coils need to be electronically reversed. This can be achieved either by winding one coil clockwise and the other counter-clockwise, but nobody does it this way. Pickup manufacturers or winders usually have a winding direction that they are comfortable with, and they always wind the coils in the same direction. The polarity reversal is achieved simply by switching the wires of one coil. So, basically, you’d connect the end of the first coil to the end of the slug coil, and you would use the starting sides of both coils to connect it to the system. This is mandatory for achieving the recognizable fat and smooth sound of a humbucker and for noise cancellation (hence hum-bucker).
If the coils in the humbucker are not magnetically and electronically reversed, the pickup will not sound right. It will have a thin, nasal, or "phasey" sound. Or maybe it will sound right for someone - it did for Peter Green.
Now, there are many different humbuckers on the market today. New technologies have been implemented, and new designs have come to life, but fundamentally they are very, very similar. Usually, the coils are not wound exactly the same, with the main coil tending to have a bit more windings compared to the slug coil. But for the purposes of this demonstration and analysis, I will assume that the humbucker is made of two exactly the same coils. This just simplifies the math.
One more thing to point out: I will be using some slightly technical terms now, such as inductance, capacitance, and resistance. So, I highly recommend you check out my other article on pickups: The Pickup Equation: Resistance, Inductance, and Capacitance Demystified. Do your homework before continuing!
