How to Change Humbucking Guitar Pickup Magnets
A Quick and Easy Way to Alter an Electric Guitar's Sound
Sep 16, 2009
Magnet changes are most easily accomplished with hum bucking pickups that use bar magnets held in place by a base plate and four screws and no metal covers. The modification is reversible. However, it is important to note that disassembly will avoid any manufacturer’s warranty the item might have had. For this reason, it is best to practice with a spare pickup, if possible.
Materials and Tools for Humbucker Maintenance
Changing a magnet begins with having a replacement magnet on hand. While it is possible to go directly to manufacturers, there are several Internet-based specialty stores that supply replacement magnets in the proper dimensions.
Common varieties of magnet used in guitar pickups include various grades of ceramic and alnico. Ceramic magnets are formed by bits of magnetized metal embedded in a ceramic matrix. In most pickup designs, the alloy known as Alnico (a contraction of Aluminum Nickel Cobalt) is commonly said to “color” the response of a pickup more than ceramic or rare earth magnets.
In general, Alnico magnets have a “rounding” effect on the frequency response, similar to the audible difference between solid state and tube amplifiers. This effect can also be heard in speakers with Alnico or ceramic magnets. There are, of course, exceptions to the general rule based on pickup design.
- replacement magnet
- rubber eraser
- tuning fork (optional)
- Electric hairdryer (optional)
- Small Phillips head screwdriver
Replacing the Humbucker Magnet
The watchword here is “care.” Most pickups are surrounded by a strip of protective tape, but this is no match for the point of a misdirected screwdriver. There is usually no way to repair severed pickup coils. Never attempt to force the magnet from its holder; in some pickups, magnets are glued to the base plate.
- To replace a magnet, remove the humbucker its pickup ring or holder. With a Phillips screwdriver, loosen the screws on the bottom plate.
- Carefully lift up the protective tape on both ends to access the magnet underneath the coils. Next, push the magnet out with a blunt object such as a flat tipped pencil eraser. If the magnet still seems lodged, the wax coating that surrounds it may need to be heated in order to loosen it. A few seconds fanning a hairdryer over the back of the base plate is usually all that is needed; the wax should not be allowed to liquefy. Unless attempting to reverse the polarity of the pickup, before pushing out the magnet, ensure make that its replacement magnet will be orientated with the same polarity. This can be done by placing the side of the replacement magnet next to the side of original. If the two repel, flip over the new magnet and ensure it adheres to the old magnet. Once this is confirmed, push the original magnet out. It is best to mark the original magnet with a permanent marker to indicate the magnet type and the direction it was facing in the pickup.
- Push in the replacement magnet using the eraser. Tighten the screws on the bottom plate and replace the pickup in the guitar. If the goal of the change was to ensure that the magnet will create the humbucking effect with another pickup, it is advisable to test the effect to plug in the instrument and use hold a tuning fork over the coils before replacing the pickup into its cavity or holder.
Hearing the Humbucker Difference in Magnets
Because each type of magnet is made of a different ratio of metals, its magnetic field varies and in effect it “hears” different parts of the string vibration. Since no two pieces of wood are identical with respect to density, mineral and water content, etc., the same pickup in two otherwise identically built guitars may sound different. This opens the door for experimentation when it comes to changing the sound and output characteristics of an electric instrument.
In order to make a direct comparison of the differences when changing magnets, a pickup’s height and placement should be recorded prior to exchange. This can also be accompanied with an audio recording to serve as a benchmark.
Changing the magnet can result in only a subtle change in response, or it can make a night and day difference. It is worthwhile spending time playing familiar patterns on a guitar whose pickup magnet has been changed in order to get a feel for the new magnet's effect on response.
Experimenting with various pickup heights for different magnet types can reveal their relative advantages and disadvantages. A magnet with a stronger charge such as Alnico 8, for example, might have an unwanted audible effect by pulling lighter strings out of tune when set to the same distance where a weaker magnet such as Alnico 2 might be at its best. Since string excursion, or side to side movement, is less near the bridge than at the neck, Alnico 8 magnets are most oftern recommended for the bridge position. The most common grade of Alnico used in hum bucking guitar pickups is Alnico 5, and for this reason it is often used as a basis for comparing other grades.
Ultimately, a successful swap is in the ear of the player and the audience. It can be a cost-effective first course of action to improve or alter a guitar's tone, before resorting to the purchase of new pickups or having a pickup's coils rewound. As such, it can be an extremely rewarding do-it-yourself project, especially when it turns out that the sound in the player's head was only a magnet away.
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