A pickup is integral to an electric guitar, and also an acoustic guitar to an extent. It comes embedded in the body of a guitar and helps convert string pulsations into electricity. Electric guitar pickups comprise six magnetic bars and a black bobbin, with an enameled wire encapsulating the magnets. The multiple bars help pick up better sound from the different strings. Some types of guitar pickups could come equipped with metal rods in place of magnets. In such pickups, a narrow and long magnet is laid below the bobbin.
Guitar Pickup Construction
So, how exactly are guitar pickups made? Based on the type or brand, a guitar pickup could vary slightly in its making or build. However, the base method is pretty much the same across the board.
The construction of a guitar pickup starts with flatwork, which basically refers to the flat pieces of plastic or fiberboard. The flatwork comes with circular holes that either hold:
- cylindrical magnets, known as pole pieces, or
- ferrous metal cylinders referred to as slugs
The slugs have a bar magnet underneath them. Also, the slugs or magnets are held apart with precise gaps between them, similar to the gap that exists between an electric guitar’s strings.
Irrespective of pole pieces or slugs, extremely fine magnet wire, which has a very thin varnish coat, gets wound around the magnetic edifice several thousand times with the help of a mechanical winder. Pretty even, smooth winds help make a stronger, darker pickup. Scatter wound, uneven coils, on the other hand, help create a crisper pickup, courtesy the decrease in self-capacitance. As crazy as it may sound, some of the best classic pickups have been made by inattentive, lazy factory workers.
After all these steps, you end up with a small electrical generator. When a piece of metal breaches the magnetic force’s lines, a small voltage gets induced into the wire coils.
The Pole Piece is Vital to the Build of a Pickup
When you start to make a guitar pickup, you would realize that the pole piece is absolutely important to the tonal puzzle. The pickup of an electric guitar is basically an inductive sensor that comprises, as mentioned above, a coil that’s wrapped around a magnetic pole piece or multiple pole pieces. This is how the most popular and important pickup designs are arrived at, which includes the traditional Stratocaster pickup like these top Strat pickups. This sensor sits underneath a string that’s made from a magnetic metal.
As aforementioned, the coil generates a signal when the string throbs. But the question is: How does this signal generation actually happen? The string-pickup correspondence is commonly represented from a point of view that is focused on the pickup’s magnetic field. In this interpretation, the pickup’s magnetic field gets perturbed by the string’s vibrations. The metal string in a way pulls at the pickup field as it vibrates, which causes the coil to create a signal as a response to this moving magnetic field.
This is how pickup functions are perceived to be in books, forum posts, and websites that are authored or contributed to by guitar players, pickup winders, and gear heads. And it’s not that difficult to understand why is that so since the magnetic field geometry’s role has been focused on extensively in the discussion relating to pickup design, performance, and tonality.
However, there’s yet another perspective, which is usually quite prevalent in books that have been authored by engineers and physicists. This interpretation is more focused on the string playing the role of the magnet. The pickup’s magnetic field magnetizes the string within the area that sits over the pole piece. Upon string vibration, the region becomes a magnetic flux source, which basically means the magnet moves in the coil’s vicinity. When viewed at a model that’s created from this perspective, the coil is basically receiving the magnetic flux that is being created by the string’s moving magnetized portion.
There are a couple of unique fundamental mechanisms pertaining to signal creation. In the first perspective, the pickup’s magnetic field is an important aspect of the equation. Moreover, it’s the motion of the field lines related to the pickup that generates the signal. In the second mechanism, wherein the vibrating magnet is the string itself, the pickup need not have its own magnetic field, provided the string has magnetization.
If you’re considering making a pickup magnet of your own, all these pieces of information would help you make a technically sound pickup. Even if you are not going to make your own pickup, the information is still worth imbibing if you have any interest in guitars.
Other Things to Consider When Making a Guitar Pickup
Without pickups, guitar amplification is just not possible. Therefore, when making a guitar pickup, it’s imperative to arrange the magnets in a manner that they are closely positioned to the guitar strings. This would ensure the magnets pick up the sound waves every time the strings vibrate, and an electric signal gets created to be sent via a lot more wires and also a cable that extends out from the guitar body’s input and within the amplifier.
There are a couple of ways in which string vibrations could be picked up: active or passive. Passive pickups basically do not need a battery for creating amplified sounds. Active pickups, on the contrary, do require a battery. Also, there are two kinds of both active and passive pickups: humbucker or single-coil. A humbucker is essentially two individual coils wired with each other to decrease or otherwise cut out the “hum” sound.
Active pickups and passive pickups have their own unique tones. An active pickup’s tone is usually known for having a lot more consistent quality. It’s a lot more customizable, thanks to the support for an equalizer that lets you adjust the string’s real sound frequency and, therefore, the musical pitch – lows, mids, and highs. Those who play a lot of metal use active pickups. Even then, it could be used for creating a powerful, full-on, bluesy-psychedelic sound.
A guitar’s tone, at the end of the day, is more about personal preference. There is no right or wrong tone. Not to mention, a guitar pickup and its construction play a role in the same.