A fuzzbox (or fuzz box) is a type of stomp box comprising an amplifier and a clipping circuit, which generates a deliberately distorted version of the input signal. As opposed to other distortion guitar effects pedals, a fuzzbox boosts and clips the signal sufficiently to turn a standard sine wave input into what is effectively a square wave output. This gives a much more distorted and synthetic sound than a standard distortion or overdrive. Fuzzboxes were the first distortion devices not based on vacuum tubes. It should be noted that the term "fuzz box" is often used generically to refer to any effect pedal that produces a distorted sound.
The generated signal is rich in extra harmonics of the input signal, particularly odd harmonics, and will also produce cross-modulation between any non-harmonic components of the input signal, leading to dissonance. For this reason, power chords are often used when using fuzzboxes to reduce dissonance.
Early fuzzboxes used germanium transistors. By the end of the 1960s, these were replaced by silicon transistors. Silicon transistors are desirable for a number of reasons. They are generally less affected by changes in temperature and offer more reliable performance than germanium ones. Warm conditions (such as the heat generated by stage lights or sunlight in outdoor performances) can adversely affect the tone of germanium fuzzes. Also, fuzz boxes that employ germanium transistors do not work well when placed after another effect pedal that uses "buffered bypass." This is because the buffer on effect pedals converts the guitar's signal from high to low impedance (to retain high frequencies and signal strength). Low impedance signals that pass through germanium-equipped fuzzes tend to suffer from a pronounced drop in volume and bass response. Today, some fuzzbox builders offer pedals with germanium transistors again, as they are typically associated with "classic" fuzz tones of the 1960s. Additionally, some units employ both silicon and germanium transistors.
The fuzzbox is associated with rock music, particularly artists such as Jimi Hendrix, Mudhoney, the Smashing Pumpkins and George Harrison. Famous examples of fuzzboxes include the Maestro Fuzz-Tone, the highly-sought Mosrite FuzzRITE, the infamous Fuzz Face (originally made by the Arbiter Group) used by Jimi Hendrix, the Big Muff Pi (made by Electro-Harmonix) and the Vox Tone Bender. Given the raunchy, unsettling sound of the fuzzbox and its similarity to the aggressive sound of a motorcycle engine, it has also became strongly associated with a genre of psychedelic, antiestablishment biker rock popularized by Davie Allan and the Arrows.
An infamous fuzz box used by Colin Greenwood of Radiohead, the Shin-ei Companion FY-2, has been compared to the sound of a chainsaw. Colin Greenwood also uses the well-known Lovetone Big Cheese.
The Ventures had the first chart single to utilize the fuzzbox on guitar, "2000 Pound Bee" (December 29, 1962); this track utilized the Mosrite FuzzRITE.
Fuzzboxes gained wider popularity after a distorted sound was popularised by Dave Davies of British Invasion band The Kinks. He played through a small 8 or 10 watt amp whose speaker cone he had slashed with a razor blade, distorting the signal. In 1964 he plugged the doctored amp into a Vox AC30 to record You Really Got Me, the band's first No. 1 single and the first popular rock 'n' roll song using a distorted power chord riff. Fuzzboxes became popular as a much easier way to create a distorted sound.