Coil Taps Vs. Coil Splits
Hi there! “Why is there a safety pin on this humbucker?” and other common questions, the answers to which are way simpler than you might expect.
This week I’m going to talk about two common pickup mods and dispel some common misconceptions. Yep, I’m talking about coil taps and coil splits. You might be surprised to find that they are actually two different things, but it’s true. One of these things is not like the other! I often find that people use these two words interchangeably, so I want to take this time to clear up the confusion.
Coil Taps
These are not coil splits, which they often get mistaken for. We’ll talk about those next. Remember that we call the wire wrapped around the pickup magnets a coil? Good. A coil tap is just another wire that pokes into that coil somewhere in the middle and becomes a second output for you to do whatever you want with. It’s kind of like “tap” water that you get by tapping into a water main, or by tapping into a well. It doesn’t change the overall flow of water, but it provides it an alternative way for it to flow, which we control with a spigot that opens or closes that ability to flow—on your guitar, we don’t call it a spigot, we call it a switch.
Since the number of winds in a coil are directly related to the volume output, when we tap into a coil somewhere in the middle, the output will be equivalently lower in volume. The reason this is cool is because of another interesting property of electric pickups: The more winds around the magnetic pole pieces a pickup has, the louder it will be, sure, but it will also gain low and mid frequencies, giving an apparent loss of high frequency definition, so a coil tap can offer a different tonal option, with the fewer windings. Often “low wind” pickups are marketed as “vintage,” which is basically a euphemism for “lower output, and higher clarity.” Way back when, before distortion was popular, it made the most sense to wind pickups “low” so they wouldn’t overdrive the amps that they were driving.
The thing about coil taps is that you can’t really make one yourself without unwinding your pickup, soldering in a tapped output, and then rewinding it back where it was originally. Because this is usually prohibitively time consuming, some pickup manufacturers offer custom tapped options on their pickups. If they don’t advertise it, you can always call and ask!
But how would you wire a coil tap? Well, you could do it any way you like. The tapped output operates exactly like the regular signal output, so one pretty common option is to send it to a SPDT switch that selects between the lower output and the higher output. To do this all you would need to do is connect both signals from the pickup to the top and bottom contacts of the switch, respectively, and send signal out from the middle contact.
So when the switch is up, one is connected to signal out and the other is not, and when it’s down, vice-versa. You could put two different pickups with coil taps on one DPDT, or you could use a push/pull pot. The possibilities are only limited by your understanding and willingness to spend time focusing.
Another possibly interesting option would be to wire up a switch that would move the pickup ground around. If the coil tap lead, for example, was grounded, and the lead that is normally grounded was left disconnected (open), and the signal output lead was connected to signal output, the wire between the two connected leads would become a kind of “mini” pickup within the whole pickup. You could use a SPDT switch to move the ground from the tap lead and the normally grounded lead in the same way that you could switch the output leads to get a two different pickup sounds.
If you take this kind of thinking to its fullest, you could imagine having a DPDT switch that does both of these things at the same time! Or better yet, two separate SPDT switches that allow you to switch the ground and the signal output independently, giving you three different pickup options in one!
If you start drawing switches and a tapped pickup on paper and start connecting the wires and contacts in all kinds of crazy ways, as you trace the signal flow, soon you’ll see that you have options to flip the phase pretty easily too! Holy Mackerel!
All of this with a single pickup just because it has one extra wire coming out of it. How cool is that?
Coil Split
A coil split is also a pickup mod, but it can only be done on humbuckers. It effectively turns “off” one of the coils, leaving you with essentially a single coil pickup, “splitting” the humbucker in two.
This can be a really cool mod on a “Fat Strat” that has a humbucker in the bridge position, but it also applies to humbuckers in other guitars!
How do we do it? Well, think about how a humbucker is constructed and what we’re trying to accomplish. We need two different states, one with both pickups on, and one with only one pickup on, so that’s going to call for a switch with two throws, or DT. now we just need to determine how many wires we’re going to need to move around to get our desired results, or how many poles we’ll need—maybe single(SP), maybe double(DP), I hope not triple(3P) or quadruple(4P)! We don’t want to install a rotary switch here!
To have the humbucker function normally, it needs the negative lead from one pickup connected to ground, then for that pickup’s output to connect to the lead of the other pickup, which will result in the electrons traveling around that second pickup in the opposite direction as the first pickup.This is why it’s important to either contact the manufacturer of a pickup to determine the way they wind their humbuckers, or to get a wiring diagram that tells you which lead is which. After that, you’ll just have one lead left over, and that’s your signal output to do whatever you want with—send it to a switch, an independent volume, straight to the jack, whatever your heart desires.
This may sound complicated, and it’s also the reason most manufacturers don’t make their pickups with all four leads—also called conductors—easily accessible to you. But if you have a humbucker with just two wires coming out of it, fear not! Those other two conductors—where the output of one pickup and the input of the other connect—are just hiding. They are usually tucked between the two plastic bobbins of the pickup, and if you carefully peel back the tape wrapped around the pickup, you’ll see them soldered together and ideally wrapped in shrink tubing or some kind of insulation. All you have to do is disconnect them and splice in an extra length of wire. Make sure to put some shrink tubing on the new joint so it doesn’t accidentally short.
Once you have all four conductors long enough to work with, you can really start to get crazy.
But before we go crazy, let’s just figure out how to shut off one coil.
Since we know that we have to have the two center conductors connected to have the humbucker work in our first switch state (both pickups need to be “on”), all we have to figure out now is what our second switch state with only one pickup “on” looks like.
We know that a pickup works by connecting one end of the coil to ground and the other end to output. The way the humbucker is wired, we already have a lead connected to output, so let’s just leave that alone. Now all we have to do is connect the other side of the pickup that is already connected to output to ground. But, but, but! It’s already connected to the output of the other pickup! Ahh!
Hey don’t worry, it’s no problem! We can leave both of those wires connected. Actually, it works better that way! If we connect them both to ground, the signal that is induced from the first pickup is sent to ground (which effectively turns it “off”), and then at the same time, the second pickup has its second lead connected to ground, so that the signal it generates will go to the output that’s already connected. Just like we needed!
Now that we know what both of our desired electrical states look like, the only trick is to put them on a switch. Take a look at the diagram below. No those are not hot dogs.
As you can see, the two center leads are both connected to one lug of the switch, and ground is connected to an adjacent lug. So in one switch state, the center leads aren’t connected to anything except one another and the humbucker functions normally. In the other state, they are connected to ground and the pickup with one lead connected to signal out will be “on” while the other pickup will have both leads connected to ground, leaving it “off.” Way cool!
So now that this all makes sense, you can figure out which of the four pickup leads does what, draw them out like in the diagram, and start connecting wires to switches and tracing signal flow! The possibilities!
What this is eventually going to lead you to realize is that pickups are really simple devices, and that it’s pretty easy to wire them up to behave in all kinds of strange ways. So now you can see that humbuckers are really just two pickups. A fat Strat is just a guitar with four pickups. You can wire those pickups however you like if you understand what they are doing! In phase, out of phase, in series, in parallel, on, off, in as many combinations as you can devise your switches to accommodate!
So what does a safety pin have to do with any of this? Nothing! Just a red herring. It got stuck there because magnetism, probably dropped into the f-hole years ago. Remember not to overthink this stuff. It’s almost always just as it appears to be.
Happy Weekend!
See you next time.