Pickups

At first glance, a magnetic pickup may seem like a simple device. It consists of a coil of insulated copper wire, wound around magnets or magnetic pole pieces. Its purpose is to convert the mechanical energy of the strings into an alternating current that can be sent to the amplifier’s speaker.

Magnetic pickups are divided into passive and active types. In passive pickups, the magnetic field is strong enough to generate a usable signal directly from the coil. In active pickups, the magnetic field is weaker, so a battery-powered preamp boosts the output to an adequate level.

To build a pickup with strong output, rich harmonic content, and good sustain, all its structural components must interact precisely. High-quality materials and proper manufacturing techniques are critical. Each element contributes its own characteristics to the final tone. By adjusting or selecting materials, we can subtly shape the sound.

A common mistake musicians make is choosing pickups based solely on others’ opinions, without considering the technical specifications. Pickups can sometimes be out of phase with each other due to coil winding or magnetic polarity. This can be corrected by reversing the magnetic polarity or reversing the coil wiring, restoring proper phase alignment.

Another issue is magnet weakening, which can occur over time due to age, exposure to strong magnetic fields (e.g., amplifier speakers or motors), high temperatures (leaving an instrument in a car on a hot day or near heaters), and, more rarely, impact. In most cases, magnet recharging can restore their strength to nearly original levels.

A common mechanical fault is a broken coil wire. Depending on the damage, the solution may involve reconnecting the wire ends or performing a complete rewinding with wire of identical gauge and specifications.

Finally, a problem often observed in low-quality or aging pickups is microphonic feedback, where vibrating components resonate at certain frequencies, producing unwanted squeals. This can be solved by wax potting the pickup, which stabilizes the components and prevents vibration-induced resonance.