The Fuzz Face is an effects pedal used mainly by electric guitarists, and by some bass players. It is a stompbox designed to produce an overdriven sound from an electric guitar. This "fuzz" sound is sometimes compared to the sound of a damaged speaker. In fact, early efforts to achieve this type of sound included actually ripping or poking holes in guitar amplifier speakers.
Such guitarists as Jimi Hendrix (one of the best known Fuzz Face users), Eric Clapton, Jimmy Page, Syd Barrett, and others have used the pedal to make their legendary sounds. The Fuzz Face is sometimes confused with the Electro-Harmonix Big Muff fuzzbox due to the resemblance of their sounds on recordings; Jack White and Mudhoney (who named an album Superfuzz Bigmuff) have erroneously been said to use the Fuzz Face instead of the Big Muff Pi, just as guitarists such as Hendrix were mistakenly have been said to have used the Big Muff.
The distinctive sound of the Dallas Arbiter version of the Fuzz Face is said to come from the germanium transistors used in its manufacture. Later versions of the circuit changed to silicon transistors. These provided for a more stable operation. It is said that some of these versions sounded harsh to the ear. However, many Jimi Hendrix recordings in the latter part of his career feature this type of fuzz face.
The electronics are contained in a circular-shaped gray, blue or red metal housing. The unit was originally intended to replace the base of a microphone stand. The pedal uses two knobs, one for volume, and one for the amount of "fuzz" the pedal produces. The arrangement of controls on the box suggests a face, with the volume and "fuzz" controls as eyes, the "in/out" stomp switch as the nose, the logo as a smiling mouth, and a wedge-shaped rubber mat suggesting a beard.
According to some sources, professional musicians would try different units from a batch in order to find one which sounded the best to their ears.
The circuit uses the property of transistors known as "saturation". When used as an amplifier, a transistor's output level is directly related to the input level, but if the input level is high enough the output reaches a maximum and goes no higher, regardless of the input level. The effect is to "cut off" the peaks of sound waves leaving a flat line instead of a rising curve. This introduces extra harmonics into the sound, producing the distortion or fuzz. The circuit of the basic Fuzz Face uses one transistor to amplify the input signal so that it partially saturates the second transistor, from which the output signal is taken.
In extreme cases the smooth input wave is converted into a square wave which sounds harsh. This tends to occur using transistors with very high gain (output current divided by input current) where the first transistor's output is so high that the second one saturates quickly. Germanium transistors have low gain compared to silicon transistors, which may explain the preference among musicians for the models made with germanium transistors.
There is debate amongst Fuzz Face enthusiasts as to which were the first transistors to be used in the unit. Most people generally agree that the AC128 transistor was the first, though a few say that the NKT275 was the first. Still others claim that the "Arbiter" Fuzz Face , (the first run of the unit) had SF363 transistors in it (See 1992 Guitar Player Mag. Distortion Special).
Modern Fuzz Face clones and modifications to the circuit use a variety of transistors, and given the subjectivity of guitar tone, there is no clearly preferred transistor.
The pictured box has another modification: a power switch. Most guitar effects pedals have the input socket wired so that the battery is connected when a plug is inserted. The plug must be removed to avoid draining the battery, especially in early models with "leaky" transistors. The power switch allows the box to be left connected, an advantage where the musician might have several effects connected together.
Many copies and reissues have been introduced and had little success due to different materials used in their electronic components. Jim Dunlop Manufacturing currently makes the pedal, but schematics and DIY plans to build your own Fuzz Face clone are abundant on the Internet; its simplicity lends itself to experimentation with different components to alter the sound.