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Selecting Guitar Pickups – Science or Art?

December 7th, 2011

Without a doubt, if you want to change the sound of your guitar the biggest single difference you can make is to change the pickups. Anything else: Bridge, saddle materials, pots, caps or tuners are refinements and tweaks that may or may not have a noticeable effect. But changing a pickup can have a mild to radical effect on the sound of your guitar. So how do you select a pickup with any level of certainty? After all it is a “blind” purchase, and aside from a demo guitar or sound clips there really is not an effective way to audition a new pickup.

Like music itself, making pickups is a blend of science and art. Furthermore, describing how a pickup sounds practically has it’s own vocabulary. You’ll hear words like “cluck”, “chime”, “hot” and “glassy” among other words to describe how pickups sound. To some degree you just have to immerse yourself into the world of pickups, read a lot of descriptions of various pickups, listen to sound clips or demo videos where available, and  learn to relate what they are saying to what you are hearing. Like wine buffs, “pickup geeks” have their own language. But at the risk of generalizing, there a some basic categories and classifications that most people can agree on.

Conventional Pickups – By this I mean pickups that follow that follow the classic construction and material techniques set forth by industry pioneers at Fender, Gibson, Rickenbacker, etc. Within the world of conventional pickup designs there are arguably three typical configurations:

Fender® Style Single Coil – Essentially thousands of turns of fine gauge magnet wire wrapped around a bobbin with six individual magnet pole pieces. Some erroneously call it an electromagnet, but a pickup is actually an inductor. The vibrating strings disturb the pickup’s magnetic field and induce a current (signal) in the coil which goes to your amp and the rest is history, and a lot of it. This type of design is famous for clarity, good string definition, high end response, and the propensity to pick up stray electrical noise (hum).

The P-90 Style – This design was introduced by Gibson® in 1946, although there were earlier similar designs. The p-90 is a single coil pickup but the (6) pole pieces are threaded steel screws that pass through the coil with a bar magnet located beneath the coil. The overall coil resistance of the P-90 is generally higher than the Fender single coil, and the magnetic field is different. P-90’s tend to be higher in output with a thicker midrange and less clarity at the high end. The P-90 has gone in and out of vogue over the years, but a good P-90 is a joy, especially in the bridge.  Some Fender-type pickups are really “imposters’ and actually follow the P-90 design. For example, many Fender MIM (Made in Mexico) and some Godin Stratocaster-type pickups are actually steel pole pieces with bar magnets beneath the coil. Usually this is a cost-driven decision although they can sound pretty good. P-90’s share the same noise issues as the Fender pickup, sometimes worse.

Hum Canceling (Humbucker) – Invented in 1955 by Seth Lover, who worked at Gibson. The humbucker pickup uses two single coils wired in series and out of phase. Using what is call common mode rejection, the two coils cancel most of the hum. Humbuckers are characterized by a fuller, thicker sound than a single coil, a strong midrange, but also with less high frequency response and upper end clarity. Nearly all Humbuckers use a construction similar to the P-90, with a bar magnet underneath the coil, and threaded screws or steel pole pieces that pass through the coil. There are many variation of the humbucking design: The coils can be in line which is the most typical configuration, facing each other with the pole pieces in between the two coils, or stacked which gives the appearance of a single coil pickup. The Precision Bass and G&L Z-Coil pickup have two coils side-by-side with each coil covering just half the strings. This provides hum canceling benefits while retaining a more single coil tone.

Variations on a Theme – For many, the best pickups were invented nearly sixty years ago, and that’s that. But there is always somebody our there trying to improve the breed and there are some notable examples. Lace Sensor has been producing uniquely designed hum cancelling pickups for many years, aimed primarily at Stratocaster players. Their Lace Alumitone pickup is a real departure — in both looks and sound — from a normal pickup and combines both noiseless operation and a very broad frequency range. The G&L MFD (magnetic field design) pickup in terms of construction is really very much like a P-90. However, the MFD has a fairly low coil resistance and larger magnetic field. The result is high signal output and a broad, flat frequency response. The term “hi-fi” is often associated with MFD pickups because they don’t over accentuate any particular frequency. Guitar players in general are conservative bunch, and many shy away from anything seen as deviating from past classics. But the Lace, MFD, and noiseless pickup designs from Lindy Fralin and others offer some real alternatives to the classic limitations of pickup design.

Can you buy a pickup on “specs”?

There are a several ways to characterize a pickup by measuring certain properties. However some of those are hard for the typical consumer to relate to. The most common measurement of a pickup is resistance (usually in thousands of ohms, or KΩ). Resistance is essentially the DC resistance of the pickup coil. Resistance can generally describe the approximate output of a pickup, and typically higher resistance pickups are hotter (louder) pickups. Resistance can be increased by either more windings, or changing the gauge of the magnet wire, or a combination of both. While we are talking generalities, higher resistance pickups will often have more midrange and less high frequency response, and a “fatter” sound.  As mentioned earlier, pickups are not actually resistors but inductors, and inductors are measured in Henries. Lace actually lists the inductance of their pickups, but I’m not sure that is of much value to the average guitarist.

Magnet power can be measured too, but measuring the magnetic field of permanent magnets is quite complex, and beyond the realm of most of us. Different magnet materials such as generic ceramic magnets and the revered ALNICO (Aluminum, Nickel, Cobalt) have differing magnetic properties, retain their magnetic properties differently over time. Some pickup makers will actually “age” their pickups, essentially demagnetizing them (degaussing) to replicate how an old pickup might sound now. So magnet efficiency and material (Ceramic, ALNICO 2, ALNICO 5, Samarium Cobalt) do make a difference in pickup sound and efficiency, but most people rely on subjective descriptions rather than hard measurements. You can always subjectively measure the magnetic properties of a pickup by taking a small screwdriver and seeing how strongly it is attracted to a pickup pole piece. Again talking in generalities, stronger magnets will induce a greater signal in the coil and produce more output.

Many months ago I was swapping out some pickups in my son’s “Highway 1” Telecaster. It’s a nice guitar, but I’m a Rio Grande dealer and wanted to road test some of their product. The stock Telecaster bridge pickup sounded pretty good but was maybe a little thin. I measured the resistance, and it was a whopping 11K ohms. But the magnets had almost no “pull” on the screwdriver. The resistance of the Rio Grande Halfbreed Tele bridge pickup was a more normal 8K resistance, but the ANILCO magnets had a much stronger subjective pull. The result? Both pickups had similar volume output but sounded different. If we looked at the Highway 1 pickup solely in terms of resistance we would think, “wow that’s going to be really hot”. But not knowing the magnetic field of the pickup showed how resistance is a incomplete measurement by itself. It’s reasonably safe to say that selecting a pickup by reading the manufacturer’s technical data is not going to accurately describe the tonal qualities of the pickup.

So How Do I Select A Pickup?

Without being a wise guy: It’s a journey. As mentioned earlier it’s important to read pickup reviews, gear pages, and manufacturer’s websites, and experiment a little by trying out some pickups. If you can handle a screwdriver and a soldering iron, the world is your oyster. If you try a pickup and don’t like it very much, chances are somebody on eBay will. Keep in mind that pickups will sound different in different guitars, so it’s most effective to experiment with your own guitar.

There are many other factors that affect the sound of a pickup than just resistance and magnetic force: Winding pattern, winding tension, potting (usually a wax material applied to the coil to help prevent feedback), bobbin size and height, etc. It’s impossible for the consumer to predict the effects of all these potential design considerations. It’s for the manufacturer to do the proper R&D to determine what variables give them the sound they want within their cost targets.

Do not assume that only boutique manufacturers can produce good pickups. There are many small winders devoting tremendous energy into recreating the vintage vibe of early pickups, but reverse engineering a 1957 PAF may not be the solution to everybody’s needs. Larger companies can do a lot of R&D and invest money into building very consistent processes. Just because “Company A” sells thousands of “shred-o-matic” pickups at the local big box does not mean they can’t satisfy the needs of a blues traditionalist. I work with a guitar builder that often uses boutique pickups in his guitars but also really likes the DiMarzio Area 51 pickups and encourages their use. I sell Rio Grande pickups, and they don’t get hung up on creating vintage reproductions. Their focus is to build great sounding pickups for a variety of applications. I wish they would write better descriptions on their website, but I’m OK taking the time to write my own. I also really like the G&L MFD pickups (not all of them equally though) and their large MFD is probably my favorite pickup to play. But it’s not a vintage anything, and especially not a traditional Fender single coil. Leo Fender developed the MFD because he was trying to develop something that was even better. He was looking forward, not backwards.

So while there is science in pickup building, the selection of a pickup is almost totally subjective, and purchasing pickups just based on specifications or snob appeal will not lead to guaranteed satisfaction. Read, listen, test, experiment, and develop your own understanding of what works for you. And don’t forget to practice in between pickup swaps!

 

 

 

 

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