Picking a Replacement Pickup
By Gene Imbody - 7/26/2001
In the last installment (related story) I attempted to shed some light on a widely misunderstood area of guitar maintenance. I'm going to continue that theme by discussing the anatomy of an electric guitar pickup--specifically, how to make an accurate decision when choosing a replacement pickup.
Like the Truss Rod, guitar electronics baffle many players, although they are about as electronically simple as it gets. This article will be limited to passive guitar electronics found on the majority of instruments. The tone of active pickups that run on battery powered preamps is determined more by the design of the circuitry than by the physical aspects of the pickup itself.
So, how can you choose a pickup without hearing it? Well, the truth is, you never really hear what a pickup sounds like until it's in your guitar…even listening to the same pickup in a different guitar won't tell you. The secret to making an informed choice is to answer a few questions about your guitar and your playing style, then combine that with the information here.
Start by putting on a fresh set of strings and play the guitar unplugged to get an idea of what you have to work with. Does the instrument sustain well? Is it clear and loud, or more subdued? Does it have strong bass or a bright treble response? Taking stock of the natural qualities of your guitar will help you decide what pickup bests suits the strong points of the instrument, and which may enhance its shortcomings. Also pay close attention to your set-up. While low action and slinky strings are easy to play, they do little for the tone of the instrument. Remember…the acoustic sound is the heart of your amplified tone!
Know how you want to define your sound. After you know what you have to work with, you need to know where you want to be. Once you are familiar with the guitar's acoustic tone, take note of what you dislike about the amplified sound. Do you need more gain or sustain? Is your sound brittle or too warm? If the guitar has powerful bass acoustically, and sounds muddy when plugged in, then you may not have a pickup best suited to your instrument. It is also extremely important to consider your amplifier. Even the best sounding guitar with the proper pickup will sound poor through an inferior amplifier. To be sure, try your guitar through several different amps…and use good quality guitar cables! The extra money spent on quality cables will help prevent degradation of your sound. Try to keep your cable under 15ft. The longer the cord, the more signal and high-end fidelity you lose on the way to the amp. Some of the really expensive cables are better suited to longer lengths; so, if you need to have the distance, spare no expense on cables!
|
Now it's time to get an idea of what makes one pickup sound different from another. Figure 1 is an exploded view of a basic Gibson style humbucker. A humbucker is nothing more than two single coil pickups (think Fender Stratocaster) joined under the right circumstances to make it immune to 60 cycle hum (that annoying buzz often heard from fluorescent lights.) However, when comparing the sound of pickups it is important not to compare single coils to humbuckers. Both have a tone unique to their design that makes it difficult to compare one to the other, but the basic construction of a single coil is a lot like half of a humbucker.
Manufacturers have different ways of evaluating sound; but, for the sake of simplicity, we will only concern ourselves with two basic aspects that should be readily known: the magnet type, and D.C. resistance.
The magnet is the heart of a pickup, and the source of the character of the pickup. As a string vibrates in the flux field created by the magnetization of the polepieces, an alternating current is created and sent through the coil windings to be interpreted by your amplifier as sound. That's oversimplified, but it's all a player really needs to know about the technical operation of a pickup.
The three most common magnets are Alnico II, Alnico V, and Ceramic. Occasionally you may encounter an Alnico III. These where the magnets used in original Fender pickups from the early 50's (they have used the other magnets as well through the years.) If you are looking for an authentic vintage Fender tone, search for a pickup with Alnico III's. Alnico stands for the basic composition of the magnet: aluminum, nickel, and cobalt. Ceramic are a combination of iron and several rare Earth materials. Alnico II is a warm sounding magnet that produces a smooth midrange and good sustain. Alnico V is stronger and produces a glassy high end with good bass response. Ceramic magnets are the most powerful of the three, and have an aggressive voice with good treble and punchy bass. In general, Alnico II's are good for instruments that lack low end, and Alnico V's are good for instruments that tend to sound muddy. Like Alnico V's, ceramics are also good for bass heavy guitars, but are better suited for players who need high output and more distortion.
Next comes D.C. resistance. DC resistance is determined by the number of turns of wire around the coil, and the diameter of that wire. This is measured in ohms, and gives a general idea of the overall output and tone of a pickup. A higher D.C. resistance can mean a higher output pickup, but as this number increases the treble response decreases, and midrange is boosted. A low resistance pickup may sound clean and bright, but will lack the punch of a higher rated pickup. Conversely, a really hot pickup may lack clarity and a solid clean tone. Combine these rules with the characteristics of the magnet, and you can form a basic assumption of the pickup's tone. For example, a pickup with a ceramic magnet rated at 12K ohms would have the gain and hard edge a heavy rock player would appreciate, while a pickup at 6K ohms with an Alnico V would be better suited for a jazz or blues player.
Other points to keep in mind when choosing a new pickup are metal covers, and control pots. Adding a metal cover may warm a brittle pickup, while removing the cover may brighten a muddy pickup. Furthermore, lowering the value of a pot(s) can fatten the tone, while increasing value brightens the tone. Most humbuckers use a 500K ohm potentiometer, while single coils commonly use 250K ohm. It is also important to keep in mind where the pickup is on the guitar. The closer a pickup gets to the bridge, the brighter it sounds, and the closer it moves toward the neck the more bass it has. A string also has a tighter vibration pattern toward the bridge than the neck; so, consequently, it is quieter through the pickup. To compensate for these differences, you often find bridge pickups that are wound to a hotter DC resistance than pickups in other positions.
These guidelines will offer a prediction of the basic sound of a pickup, but so much goes into creating the mystery of tone that it is hard to be 100% accurate. However, armed with some basic knowledge and a good idea of what your sound is lacking, choosing a pickup you've never heard can be more than a role of the dice.
