Dave’s Corner: A Pickup Primer

The market for pickups is booming. Never before have guitarists had so many great designs available to them, whether they’re looking to recapture the glories of vintage tone or upgrade and modify a modern guitar to suit specific needs. It’s hard to know what you’re after, though, and what different types of pickups will do for you without understanding exactly what factors contribute to different sounds. To the end of laying down some of the basics, here’s an “Anatomy 101” for pickups. This is something I can add to in greater detail in coming weeks to get a little deeper under the skin of these enigmatic components at the heart of our tone.

As electromagnetic devices go, pickups are at the simple end of the spectrum. They don’t have the moving parts of their siblings - the dynamic microphone (think Shure SM57) or the speaker - but massive variables within the relatively few significant parts that make up any given pickup do contribute to enormous differences in sound. Two different pickup manufacturers can build, for example, a PAF-style humbucking pickup using the exact same types and quantities of materials, but the pickups can come out sounding significantly different. Even the same maker can produce different sounding pickups from the same parts (witness original Gibson or Fender pickups from any iven era). Once you start varying some of the components and the ways they’re put together, the differences in sound and performance increase exponentially.

How Pickups Work

Before digging into the components of the pickup, let’s look briefly at how they work. A speaker produces sound when the electrical signal hits an electromagnetic coil that’s attached to a flexible paper cone, suspended in proximity to a fixed magnet, causing the coil to move and the cone to vibrate along with it. Pickups work somewhat in reverse, but without the moving-part element of the equation.

A pickup is an electromagnetic device that produces a magnetic field through which the guitar’s strings pass. When you pick a string, its disruption of this magnetic field translates that motion into an electrical signal in a coil of thin wire wound within the pickup. This signal travels down the length of wire to your amplifier. In short, electromagnets can do two things: 1) translate an electrical signal into motion by exerting magnetic force or 2) do the reverse and translate motion into an electrical signal. Pickups do the latter.

The Major Components Of The Pickup

All electromagnetic pickups as used in traditional electric guitars require at least two primary components: a source of magnetism and a coil of wire. Some are as simple as a coil wrapped around a magnet, usually with some inert fiber, plastic base or bobbin to hold everything in place. Fender Stratocaster and Telecaster pickups, for example, use six individual magnets—one for each string—with a coil wound around them.

Gibson’s Firebird mini-humbuckers or original Melody Maker single-coil pickups similarly have a bar magnet within a coil (or two, in the humbucker’s case). The more common Gibson types, though - the P-90 and the full-sized PAF-style humbucker - add steel pole pieces to the equation. These screw-like poles are threaded through the bobbin around which the coil of wire is wound, and into a base structure that puts them in contact with magnets mounted below the coil.

Other original pickup designs have their own ways of blending these components together, but the templates outlined in the above paragraph - magnets within the coils vs. steel pole pieces touching the magnets mounted below - describe virtually every type of pickup made for electric guitar.

The positioning of the magnet and presence of pole pieces are two of the most significant variables in pickup making, whether you’re talking humbuckers or single-coils. Gretch Filter’Trons or Charlie Christians? Magnets below, with steel poles or blades threaded through the coils. Gretsch Dynasonics (aka DeArmond Model 200) or DeArmond Gold Foils? Magnets within the coils.

Put simply, each of these two basic designs has what we might call a “core sound.” Obviously there will be enormous differences between pickups depending on a wide range of other factors—more of which are below—but here are the broad characteristics enhanced by these two main approaches to pickup making.

Magnet within coil: Sharper, brighter, clearer, with enhanced treble. With individual magnet pole pieces, single-string definition is improved further; with bar magnets it’s often slightly “blurrier”.

Steel within coil, magnet below: Rounder, thicker, grittier, snarlier and gnarlier, often with more aggressive midrange.

None of these are absolutes, but they are pretty reliable starting points. Consider types of pickups that you might already hear in your “mind’s ear.” You’ll likely see how they follow suit. Consider, for example, that when Gibson wanted more clarity out of the gnarly, thick, slightly gritty sounding P-90 in 1954, engineers Seth Lover and Walter Fuller simply replaced the threaded steel screws with individual bar-magnet sections within the coil of what was otherwise essentially a P-90 to create the Alnico (aka “staple top”) pickup. Voila! Improved clarity and enhanced treble content—exactly what Gibson president Ted McCarty was asking for. Naturally, humbucking and single-coil pickups of each kind sound a little different, but they still share these basic characteristics.

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The Variables

Having understood these basic templates, it’s important to be aware that there are many variables at play which can make even pickups that seem to be the same type sound quite different. Consider the number of mix-and-match combinations of all of the following, for starters, and you begin to see how many nuanced alternatives exist in the world of pickup-making.

Different magnet structures (or magnet-and-pole piece structures in many designs, as above) will respond differently, because they are creating different types and shapes of magnetic fields.

Different sized or differently structured pickups will create different magnetic fields and will “read” string vibration differently, which leads to different translations of the strings’ vibrations within the coil.

Different types of coils—whether wound in different shapes, in different patterns, with different gauges of wire, or with more or less wire—will translate the disrupted magnetic field differently, and therefore shape the signal sent to the amp differently.

Different formulations of steel components such as pole pieces, slugs, or base plates will contribute to subtle differences in different pickups’ sound and performance.

Different string types will affect the magnetic field differently. According to the type of steel they are made from, any coating or plating on the wound strings, their condition, their gauge, and other factors, a different performance could result from any given pickup.

Stir all of these into the stew, and you can see why “cracking the code” of different types of beloved vintage pickups has proved a major endeavor for even the most skilled modern pickup makers. There isn’t room here to detail the sonic results of the many iterations of each of these variables, but I’ll go deeper into related categories in future installments. My hope is to build a reference base that helps you determine in advance what types and variations of pickup might be best suited to any sound you seek. Meanwhile, be aware that the variables are many, and the slightest little tweak in the outwardly simple recipe of any given electromagnetic pickup might leave you wailing the blues rather than twanging out honky-tonk.

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ABOUT THE AUTHOR: Dave Hunter

Dave Hunter is a writer and musician who has worked extensively in the USA and the UK. He is the author of The Guitar Amp Handbook, Guitar Effects Pedals, Guitar Amps & Effects For Dummies, The Gibson Les Paul and several other books. Dave is also a regular contributor to Guitar Player and Vintage Guitar magazines.

The Updated And Expanded Edition of Dave Hunter’s The Guitar Amp Handbok: Understanding Tube Amplifiers And Getting Great Sounds is now available from Backbeat Books.

See some of Dave's books on Reverb here.


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