The Electro-Spanish Ken Roberts was also the first instrument to feature a hand-operated vibrato as a standard appointment, a device called the “”Vibrola,”” invented by Doc Kauffman. It is estimated that fewer than 50 Electro-Spanish Ken Roberts were constructed between 1933 and 1937; fewer than 10 are known to survive today. Some steel-string acoustic guitars are fitted with pickups purely as an alternative to using a separate microphone. Combinations of these types of pickups may be used, with an integral mixer/preamp/graphic equalizer. They are regarded as acoustic guitars rather than electric guitar because the pickups do not produce a signal directly from the vibration of the strings, but rather from the vibration of the guitar top or body.
These acoustic electric guitars produce a much higher resonance due to their design. This type of guitars, which provide full, rich tones, and deep bass response, are especially preferred by jazz guitarists. Electric acoustic guitars should not be confused with semi-acoustic guitars, which have pickups of the type found on solid-body electric guitars, or solid-body hybrid guitars with piezoelectric pickups. Pickups—the nodes attached to the steel strings that transferred electric currents to amplifiers—also advanced quickly about the same time. Most electric guitars had begun to use smaller magnetic single- or double-coil pickups.
Electric guitars provide the advantage of lesser effort on the strings because Yamaha electric guitars are loaded with sophisticated pickups placed at different positions. The bridge, neck, and middle pickups are designed using an optimal combination of ceramic, humbucker, or single-coil setup. Electric guitar design and construction vary greatly in the shape of the body and the configuration of the neck, bridge, and pickups. The headstock contains the metal machine heads (1.1), which use a worm gear for tuning.
A few examples of string-through body guitars are the Fender Telecaster Thinline, the Fender Telecaster Deluxe, the B.C. Rich IT Warlock and Mockingbird, and the Schecter Omen 6 and 7 series. George Beauchamp, along with Adolph Rickenbacker, invented the electromagnetic pickups. Coils that were wrapped around a magnet would create an electromagnetic field that converted the vibrations of the guitar strings into electrical signals, which could then be amplified.
Reports of playing feel are greatly complicated by the many factors involved in this perception. String gauge and design, neck construction and relief, guitar setup, playing style, and other factors contribute to the subjective impression of playability or feel. The primary metric of guitar necks is the scale length, which is the vibrating length of the strings from nut to bridge. A typical Fender guitar uses a 25.5-inch scale length, while Gibson uses a 24.75-inch (62.9 cm) scale length in their Les Paul.
By the 1970s, guitar manufacturing had become a truly international affair. The advent of computer-controlled manufacture in the 1980s and ‘90s raised the quality floor so that inexpensive, “starter” guitars became better than ever. The modern selection of instruments is astounding, both in range and quality.