How a magnetic pickup works
A magnetic pickup is a surprisingly simple device. It is built from one or more magnets and a coil of very fine insulated copper wire, often with thousands of turns. A steel guitar string above the pickup becomes magnetized by the nearby magnet. When the string vibrates, it changes the magnetic field passing through the coil, and that change induces a small alternating voltage in the wire. The frequency of that voltage follows the frequency of the string’s vibration, so what comes out is an electrical copy of the note.
This effect, electromagnetic induction, was described by Michael Faraday in the 1830s and was already used in technology such as the electric telegraph and telephone receivers. It was not new in the 1930s. What was new was applying it to a plucked string in a way that was loud, stable and cheap enough to sell.
The signal is very weak, so it must be amplified before it can drive a speaker. That is why any pickup-equipped guitar depends on an amplifier. The fine wire itself is produced by wire drawing, and a pickup’s sound depends on details such as the number of turns, the strength of the magnet and the geometry of the coil.
One limitation follows from the principle: a magnetic pickup only responds to magnetic metal. Nylon strings, used on classical guitars, produce no signal. This is why electric guitars use steel strings and why other kinds of pickups, such as those that sense vibration through the body, were developed for other instruments.
Early attempts
Before magnetic pickups became standard, inventors tried various ways to capture sound from a stringed instrument. Some used microphones, which responded to air vibration and also to feedback, and some used pickups based on pressure, capacitance or contact. Lloyd Loar, a designer and engineer who worked at Gibson in the early 1920s, is often mentioned in accounts of early electric stringed instruments and later formed his own company working on electrified instruments. The details of these devices are less well documented than the commercial instruments that followed, and some descriptions of them in popular sources may be exaggerated.
George Beauchamp and the Frying Pan
The best-documented early design comes from Los Angeles. George Beauchamp, a vaudeville musician and instrument tinkerer, worked with Adolph Rickenbacker, whose company manufactured metal parts, and others including Paul Barth. They developed a pickup with a pair of horseshoe magnets straddling the strings, with a coil wound beneath. It was fitted to a small lap steel with a round body, which became known as the “Frying Pan” because of its shape. Production models were made of cast aluminum in the early 1930s. Later models used bakelite plastic, according to commonly cited accounts.
Beauchamp filed a patent application in 1934, and a patent was granted in 1937. This timeline is sometimes taken as evidence of the first electric guitar, but sales of Frying Pans had begun before the patent was granted, and a patent date does not prove that nobody else had built something similar earlier.
The question of “first”
Several things complicate any claim to the first electric guitar:
- Definition. If “guitar” means a lap steel, the Frying Pan is a strong candidate. If it means a Spanish-style guitar, other models, such as Rickenbacker’s Electro Spanish and Gibson’s ES-150, appeared a few years later.
- Prototype versus product. Experimental pickups from the 1920s were built by various people, and some may have worked. A working prototype is not the same as a commercial instrument.
- Parallel work. Other makers, including Vivi-Tone, Stromberg-Voisinet and others, are frequently mentioned in accounts of this period. Records are limited and sources do not always agree.
- Marketing. Companies sometimes advertised “first” claims that were really about one feature.
For these reasons, careful histories tend to say that the Rickenbacker lap steel was among the first commercially successful electric guitars, and avoid naming a single winner.
Gibson and the pickup that stayed
In 1936, Gibson introduced the ES-150 with a bar-shaped magnetic pickup, designed to sit under the strings near the neck. It was fitted to a hollow archtop body, and was played by Charlie Christian in the late 1930s, so it has a special place in the guitar’s history. The pickup was sometimes called the “Charlie Christian pickup.” This instrument is often the first one named when people ask about the first widely used Spanish electric guitar, though that is a narrower claim than “first electric guitar.”
From single coils to humbuckers
The earliest pickups picked up hum from electrical interference, because a single coil acts like a small antenna. Over the following decades, designers worked on improved forms. Leo Fender’s single-coil pickups of the 1950s became classics for their bright, clear sound. In 1955 and 1956, Gibson engineer Seth Lover developed the humbucker, which uses two coils wired so that hum cancels, producing a thicker sound. These later developments improved noise and tone but followed the same underlying principle.
Pickups beyond the guitar
The same type of pickup is used on electric basses, steel guitars and some other instruments. Pickup design also relates to sound recording: playback heads on a tape recorder use magnetic induction in a closely related way, since the moving magnetic tape induces a signal in a coil. The principle of turning motion near a magnet into a voltage turns up in many technologies.
What the history shows
The first electric guitar is better understood as a process than an event. Researchers and makers in the 1920s and 1930s explored pickups, and the magnetic design that Beauchamp and others developed proved reliable enough to sell. The commercial lap steels of the early 1930s and the hollow-body models of the mid-1930s were steps along the way. A fair description is that no single instrument can be crowned the first without choosing a definition, and the evidence is incomplete enough that confident claims in either direction should be treated carefully.