It seems that guitarists talk about pickups more than anything else.
We describe them with words like “hot”, “crunchy”, “jazzy”, etc., yet most of us have no idea what makes one pickup different from the next.
So that begs the question: how do pickups work?
Well, before we get any deeper into how, let’s make sure that you first know what pickups are.
What Are Guitar Pickups?
Pickups are the reason that an electric guitar can make sound. If we are going to speak in technical terms, guitar pickups are transducers: electronic devices that help convert energy from one form to another form.
Guitar and bass pickups read the vibration of the strings and convert them into an electrical signal so that they can be played through an amp or DI interface.
Yes, you do need some type of external transducer, like an amp, to turn that energy back into vibrations that we can here.
While all pickups work similarly, there are multiple types of pickups that create different tones. Let’s dive into those so we can get a better idea of the different tones available and how each pickup type works.
Different Guitar Pickup Types
There are just about a thousand different pickups out there from a wide variety of manufacturers. It can seem a bit overwhelming when you think about it. The best way to think about pickups is in “types” rather than “brands”.
Single-coil pickups use a large coil of wire that is wrapped around a bobbin about a few thousand times. They are one of the most popular types of pickups around and can either have one structure or double structures. You’ve likely seen these pickups in pretty much every Fender guitar out there.
Until about 1955, all pickups were single-coil pickups. While single-coil pickups have an incredible signature sound that is loved by guitarists everywhere, they can be extremely noisy, as they are sensitive to electromagnetic interference found in domestic electrical grid power.
Humbuckers are built with two coils instead of one, canceling out that electrical hum, as well as any other noises that have a negative impact on single-coil pickups. Essentially, they are made to “buck” that unwarranted hum while keeping the tone you love unimpaired.
The two coils on a humbucker are wound oppositely and have opposite polarities. Without getting too deep into physics, we can tell you that sound typically cancels out when opposites meet.
Think of phase polarity.
Basically, if you are looking for a large, warm electric guitar sound without worrying about annoying hum, humbuckers are the way to go.
The Vibration Of Strings
So now that you have a decent understanding of how different pickups are made, let’s look into how they interact with strings. As we know, strings vibrate to create sound. Check out the picture below:
In the very first drawing, you see the very first harmonic that comes from the pitch of the string. The large oval shape represents the string vibrating back and forth. This is known as the fundamental frequency. If you pick your open A string, for example, you’ll hear the fundamental A.
The second drawing indicates the second harmonic. As the string vibrates, it creates multiple frequencies of the fundamental pitch. Even though you don’t realize it, as it is difficult to see, when you pick your string, you create both smaller and larger vibrations.
The smallest point in those vibrations is known as the node. As you may have guessed, the largest point is called the antinode.
The number of harmonics that come from a string correlates to the number of antinodes. Look at the third drawing and you’ll see three antinodes, meaning there are three harmonics.
So how does this all relate to pickups?
Well, a pickup will only detect the sound of a string when the string vibrates close to it.
Look at the photo above. In the first and third drawing, the antinodes are closer to the pickups. In the second drawing, however, the node is closest to the pickup. This means that the pickup will not pick up that second harmonic.
Obviously, the diagram assumes we live in a perfect world where strings are plucked flawlessly every time. A vibrating string will always supply us with harmonics (the second, the third, the tenth, etc.). However, a pickup will ignore nodes that are closest to it. This is how we get tone filtering on our guitars.
Different guitars are made to enhance different harmonics. A single pickup setup on a vintage guitar will sound much different than a three-pickup setup on a modern guitar simply because of the harmonics that they cancel out.
Let’s consider the 5-way pickup switch that we find on Fender Stratocasters
When only the neck pickup is engaged, it will only cancel out the nodes that reach the point over the neck pickup. However, when you click you switch down one notch, you get a mix of the neck and middle pickup. In this position, you get a filtering of sounds that provides you with a different tone. Essentially, you are canceling out more harmonics thanks to the physics of filtering.
Higher Vs. Lower Output
A high-output pickup is made to output a stronger signal, meaning you’ll be able to overdrive an amp far easier. The reason companies use to make double-coil pickups so often is because they had a higher output than single-coil pickups.
Thanks to modern technology, single-coils are actually starting to overstep double-coil pickups in that regard.
If you have an electric guitar with low-output, single-coil pickups, you can plug into your amp and hear a clean, crisp sound. Even if you start to chug hard, the sound will remain fairly clean.
If you then switch to a guitar with hotter, humbucker-style pickups, you will likely hear a dirtier, distorted sound. Essentially what we’re getting at is the higher the output or hotter the pickup, the more distorted the sound coming out will be.
Passive Vs. Active Pickups
Passive pickups are far more common than active pickups. Wires are wrapped around the magnets of the pickups, helping to convert string energy into electricity.
That electricity then powers the pickups, meaning you don’t need any battery or other external sources to power them up.
Active pickups, on the other hand, make use of battery power from a preamp to help boost the output signal. If you are looking for high-output pickups, active pickups are your best bet. They also help to reduce the amount of string noise that you hear.
For the most part, heavy metal and rock guitarists will use active pickups because they can help your amp to distort with ease while still preserving a solid attack. Think “Metallica-style palm mutes”.
Because of the way active pickups work, they won’t get weaker over long cable runs as passive pickups do. This means they’re also excellent for players who use a ton of effects.
What Makes a Pickup?
When it comes to components in pickups, there are a few variables that never change. Whether you are interested in building your own pickups or you just want to see what pieces must come together to make working pickups, here is what you’ll find:
Magnets play a significant role in the tone of pickups, as well as the output. Both these factors depend on the type of material they are made out of and the way they are laid out. We typically find three different layouts when it comes to magnets:
- Individual Magnetic Poles: This layout is most commonly found in Fender-style guitars or any guitars that have single-coil pickups. It gives guitars a much thinner sound when compared to other layouts, which is why you get that bright Fender twang.
- Steel Poles On a Magnetic Bar: This layout gives you a much darker sound with a warmer low end. You typically find this layout on Gibson guitars, as well as other guitars that use humbucker pickups.
- Blade: This layout is the least common of the three. The pole pieces are replaced with a single bar that runs the entire length of the pickup. They are incredibly high-quality, giving you better bends and sustain with added clarity and output.
These magnets are made out of different materials, each material giving off a unique tone. One of the most frequently used types of materials is Alnico. It is a cleverly named blend of metal alloys including aluminum, nickel, and cobalt.
The reason pickup manufacturers use this blend over other metals is that it retains magnetic force over longer periods.
Alnico can be found in different variations:
- Alnico 3: provides the most gentle tone of the bunch, as it has the weakest pull. Alnico 3 is very common in old-school Stratocasters.
- Alnico 2: has a vintage tone like Alnico 3, though the output is a little stronger, allowing you to overdrive your amp much easier.
- Alnico 5: has a very high output and a versatile tone, perfect for the modern guitarist who plays many different types of music.
- Alnico 8: has the highest output and the heaviest tone. The magnetic pull is incredibly strong, making it great for rock and metal genres.
Besides Alnico, ceramic is another commonly used material to make pickups. As you can see in the video below ceramic is also much brighter. It’s best for hard rock genres and heavy metal where the guitar needs to cut through a wall of sound.
Potting is a process that you don’t hear about too often, mostly because it is a strange one. The basic idea is that every component in the pickup needs to stay attached and still so that there is no vibration or movement as you play. To make sure the pickup is steady, manufacturers dip it in wax.
Potting also helps to get rid of nasty feedback that could occur if you end up standing too close to your speaker.
With that said, some old pickups were purposefully not potted, allowing them to vibrate freely as air moved around them. This is what gives vintage pickups a one-of-a-kind sound.
When you wire humbucker pickups together, you will either wire them in parallel or series. Parallel wiring is the most common method of wiring and is used in most modern guitars with humbucker pickups. Series wiring is a bit more “boutique” if you will.
Parallel Wiring splits the signal into two parts in the beginning before combining them back together at the end of the signal chain. While parallel wiring gives you a lower output, it also gives you a much brighter sound.
Series Wiring, on the other hand, puts the signal on a one-way path through both of the coils. While series wiring gives you higher output, it also gives you a much warmer sound.
Is There a “Perfect” Pickup?
So now that you know how guitar pickups work, you might be asking yourself,
“Is there a perfect pickup for me?”
Well, the perfect pickup is the one that gets your guitar to sound exactly how you envision it. Do you want that massive tone that can cut through a wall of sound on stage? Do you want a mellow, warm tone that is good for recording in your bedroom?
The possibilities are truly endless. Pickups have come quite a long way since their initial inception. We can’t wait to see what the future holds for innovative guitar tone.