Bass guitars feature various pickup types that work to convert string vibrations to electric current, including J, P and humbucking pickups.
A bobbin doesn’t play an active role in shaping the sound of a pickup, but rather supports another essential component that does. Subtle changes to its construction can influence how its coil sounds.
Flatwork
An assortment of factors can determine the tone of a bass guitar pickup, such as its size, number of coil turns on its coil wire and type of flatwork it is wound on. Adjustments to any of these variables can significantly alter its tone – for instance too thick flatwork may lead to excessive feedback or buzzing sounds while too thin may not support enough wire windings that affect its tone as a whole.
Apart from thickness, the shape of a bobbin also plays a part in its tone. A long and thin bobbin will produce brighter sound than shorter fatter ones; similarly a taller one will deliver sharper sounds than short ones.
As quality flatwork material for bobbins can help ensure coils are wound evenly and securely, it is essential that they contain burrs free flatwork materials in order to achieve even and secure coil winding. Furthermore, fine grit paper should be used on this flatwork in order to give it a smooth surface and make coil turning simpler.
Manufacturers frequently handcraft bobbins out of wood or phenolics and hand fabricate them to their desired shape, giving them greater control over the tone of their pickups. Some companies also invest in injection molds to quickly produce thousands of bobbins at one time for less investment.
If you’re planning on building your own custom bass pickup, black vulcanized fiber flatwork makes an excellent material to use as the bobbins. This material can accommodate various string spacings with ease and cutting to dimensions is straightforward. In addition, its durability makes it suitable for single coil pickups at high temperatures without melting or deforming; kits are available that come complete with flatwork material, AlNiCo 5 magnets, copper-plated brass polepieces tubing and screws necessary to get you going on this task.
Magnets
Magnets play an integral part in creating the sound of a pickup. By inducing magnetism into strings as they pass through coils, magnets create AC current that provides bass guitar with its signature voice. Their strength varies to affect its frequency response response.
Stronger magnets produce higher inductance, increasing output; however, this effect only lasts up to a certain point before distorting and other issues arise that compromise sonic quality of the pickup.
Ceramic magnet pickups tend to produce higher output levels when played cleanly but add extra articulation when played at higher gain settings. Alnico magnets tend to provide smoother sound signatures with more midrange presence and tighter lows; ceramic pickups may sound strident at times when played cleanly but will give enhanced articulation for high gain tones.
Neodymium magnets are even stronger than alnicos, enabling pickup manufacturers to craft pickups that deliver tremendous power and punch. Unfortunately, however, neodymium magnets may produce an abrupt and harsh sound which might not suit all musical genres.
Magnets also have more subtle impacts, including on string vibration. Their magnetic force causes it to decay at various levels, producing harmonics similar to pinch harmonics – this adds dimension and clarity to your pickup tone.
Alnico magnets are one of the most widely-used types of pickup magnets, each offering its own distinct sonic character. Alnico II magnets tend to lend vintage-sounding guitars a warm and smooth tone with prominent mids and scooped top end; Alnico V magnets offer tight lows, balanced mids, powerful highs.
There are also some newer types of pickup magnets, including Alnico 8, which provides a tonal bridge between Alnico 5 and ceramic, while humbuckers use two electromagnets in one pickup for maximum sound output and aggression – an especially popular choice among hard rock and metal players.
Windings
Windings on a coil have a dramatic impact on its tone. A single coil acts both as an electrical transducer and sensor for mechanical vibrations; both functions rely on electromagnetic induction as fundamental properties.
Winding pattern has more of an effect on sound than its thickness; since coils do not transfer electricity directly. But factors like number of turns, tension variation during windings, distance between them, parallel capacitance and parallel capacitance all influence a pickup’s tonal properties.
In the past, manufacturers used different gauges of wire in order to maximize wrapping on a compact bobbin or create specific tones. Nowadays, most manufacturers utilize one gauge across their lineups, typically 42 gauge as an industry standard.
Windings’ “scatter” determines their tones; how tightly or loosely wound they are and where on the bobbin they are placed are factors as well. Some manufacturers believe that vintage pickups’ loosely wound tones contribute to their lively quality, so modern coil manufacturers strive to replicate that quality in modern coils.
No two sloppy, scattered-winding pickups will sound the same due to all their different tonal properties; finding something that matches your individual style of playing and tastes best requires trial-and-error, which this guide should assist with. Enjoy discovering what works for you!
Coils
Dependent upon the type of pickup used, its coils may either be wired in parallel or series. A series-wired humbucker features two coils working in unison to remove hum and provide more midrange and bass frequencies; conversely, one coil may be “tapped” out as a single-coil pickup with more midrange frequencies similar to that found on P or J basses.
Although coils may appear simple at first glance, they have the power to transform a guitar’s tone significantly. How they’re wound can have a significant impact on its sonic characteristics of bass guitars; this includes winding patterns like scatter-wound coils which feature wire not wrapped layer upon layer on their bobbin – often associated with open and lively tones.
Coil Slugs in Single Coils Can Have an Influence on Tone; more coil slugs produce fuller and heavier bass sounds, while increasing turn count can increase midrange and treble response while simultaneously decreasing bass output and high frequency output.
Coils can also be manipulated to alter the overall character of a bass; for instance, a “hotter” coil will feature higher voltage swing and more prominent upper frequency boost. Conversely, “warmer” coils have lower voltage swing and more subtle midrange boost. Furthermore, magnets also influence this tone: for instance larger magnets will have greater effect on low frequencies than their smaller counterparts.
Bobbins used for pickup coils are key elements of their sound properties. Their height, length and inner “island” size all affect how a coil is constructed; how it’s wound can also have an enormous effect; for example, scatter winding produces more dynamic and open sounding pickups than machine winding does.