Distortion pedals are a type of effects unit designed to add distortion to an audio signal to create a warm, gritty, or fuzzy character. Depending on the style of signal clipping, the broader category of distortion pedals is typically divided into fuzz pedals, distortion pedals, or overdrive pedals. Designed for electric guitar and bass and operated by the player's foot, distortion pedals are most frequently placed in the signal chain between the guitar and amplifier.

The use of distortion pedals was popularized by Keith Richard's use of a Maestro FZ-1 Fuzz-Tone pedal on the 1965 Rolling Stones song "(I Can't Get No) Satisfaction".^[1][2] Later pedals like the Pro Co Rat and Ibanez Tube Screamer have achieved iconic status among guitarists and are a key element in many players' tones. Industry publications often publish lists of influential and popular models.^{[3][4][5][6][7]}

Arbiter Electronics released the first Fuzz Face in 1969, featuring a unique round metal housing inspired by a microphone stand and with the arrangement of volume knob, distortion knob, and logo intentionally resembling a face. The Fuzz Face's first production run lasted until 1976/77, then was reissued from 1986 until 1990. In 1993, Dunlop Manufacturing took over production and has continued to issue several varieties of the pedal. Jimi Hendrix popularized the Fuzz Face and was known to buy multiple copies at a time to identify the best ones; his pedal chain often consisted of a wah-wah pedal into a Fuzz Face, then into a Uni-Vibe.^[8] Other notable users include Duane Allman,^[9] Stevie Ray Vaughan^[10] Pete Townshend,^[11] Eric Johnson,^[12] and George Harrison.^[13][14]

The Big Muff Pi (π), often known simply as the Big Muff, is a fuzz pedal produced in New York City by the Electro-Harmonix company, along with their Russian sister company Sovtek, primarily for use with the electric guitar. Released in 1969 and designed with an emphasis on long sustain compared to existing fuzzes, the Big Muff Pi was the first overwhelming success for Electro-Harmonix's line of pedals. Due to its reliability, its low price, and its distinctive sound, the Big Muff sold consistently through the 1970s and was found in numerous guitarists' pedal collections, including David Gilmour^[15] and Carlos Santana. The "sustained grind" of the Big Muff was later an integral part of the sound of many alternative rock bands through the 1980s and 1990s, being used extensively by the Smashing Pumpkins, Dinosaur Jr., NOFX, Bush and Mudhoney.

The Maestro FZ-1 Fuzz-Tone was the first widely marketed fuzz distortion guitar and bass effect. Introduced in 1962, it achieved widespread popularity in 1965 after the Rolling Stones guitarist Keith Richards prominent use of the FZ-1 on the group's hit, "(I Can't Get No) Satisfaction". Later in 1965, the design was slightly modified and designated as the model FZ1-1a. In the wake of the success of "Satisfaction," numerous recordings, mostly from 1960s garage rock and psychedelic acts, featured Maestro Fuzz-Tones on guitar. More significant design changes made after 1967 resulted in different renditions of the Fuzz-Tone released over the years. In the 1990s, Gibson re-issued the FZ-1a, but it was later discontinued.

Released in 1965, Sola Sound's Tone Bender was a re-creation of the popular Maestro Fuzz-Tone, but with more sustain and intended for the European market. For U.S. distribution, Vox released a version in 1967 based on Sola Sound's MK1.5 Tone Bender update, one of many the pedal went through. With different component values and transistors being used over the years, earlier variants are fuller sounding, while later ones are bright and cutting. Notable examples of the Tone Bender in use include Jeff Beck's sitar-like guitar solo on the Yardbirds' 1965 song "Heart Full of Soul" and Mick Ronson's guitar work on David Bowie's 1972 song "Moonage Daydream".^[16]

The Univox Super-Fuzz circuit was designed in the late 1960s by the Japanese company Honey, in the form of a multi-effect called the Honey Psychedelic Machine. Later on, Honey was acquired by Shin-ei, who produced the effect separately and imported it to the USA via Unicord, the parent company of Univox. The first Super-Fuzzes were made in 1968, and production continued until the late 70s.^[17] The pedal is unique in that the full-wave rectification of the circuit produces an upper octave as well as a slight lower octave. This also gives the sound a lot of compression and a mild ring modulator effect. A second unique feature is a tone switch that engages a 1 kHz filter that "scoops" the mids, giving a fat, bassy tone.^[18]

The Fuzz Factory, designed overnight in 1994, was the second pedal from Z.Vex-founder Zachary Vex. The design began with a collection of unique germanium transistors Vex purchased from a surplus store with the intent of creating a fuzz pedal similar to a Fuzz Face.^[19] While initially disappointed by the transistors' sound, Vex added a booster to the front of the circuit and the pedal went "haywire" with squealing and odd noises. Vex replaced the fixed-value resistors with pots to gain control over the sounds, leading to a layout of five-knobs—three of which he could not easily describe the function of. The local dealer Vex took the first Fuzz Factories to objected to the layout, feeling customers would be confused, but Vex insisted this would mean buyers could find their own sounds.^[20]

Dubbed a "masterpiece" by Guitar World for being intuitive yet "near-infinite in its tone-sculpting potential," the pedal's success established Vex as a pivotal figure in the popularization of boutique effects pedals.^[19]

Introduced in 1978, the DS-1 was Boss's first distortion pedal, and second pedal release overall, following the CE-1 Chorus Ensemble. The DS-1 uses two hard-clipping diodes for an aggressive edge, similar to the ProCo Rat, released the same year. This type of circuit became known as "distortion," as opposed to the soft-clipping "overdrive" of Boss's later overdrive pedals.^[21] The DS-1 uses a preamplifier instead of the conventional op-amp for a gritty, warm tone. When the original Toshiba TA7136AP preamp became scarce, the circuit was redesigned in 1994, introducing several "quirks"—lower volume levels, noise at higher gain levels, and a "waspy" edge due to higher frequencies not being filtered out. These issues led to the pedal being popular among modifiers.^[21]

The DS-1 is Boss's bestselling pedal of all time.^[22]

The Boss HM-2, first issued in October 1983, was manufactured in Japan until 1988, then in Taiwan until 1991.^[23] It was designed to emulate the mid-range response of a Marshall stack.^[24] Achieving only moderate success in the glam metal scene, the pedal was discontinued in 1991; it was succeeded by the HM-3 Hyper Metal and MT-2 Metal Zone, the latter of which became a commercial success and top-selling pedal for Boss.^[24] Following its discontinuance, the HM-2 developed a cult following in the heavy metal scene and is especially associated with Swedish death metal. In 2020, Boss renewed production of the pedal as the HM-2W, part of its Japanese-made, boutique-grade "Waza Craft" series.^[25]

The MT-2 Metal Zone was released in 1991, following the discontinuation of the earlier HM-2, which failed to sell well during its production run, but was popular among death metal players. With the MT-2, Boss sought to appeal to that market with an improved pedal as death metal's popularity surged.^[26] The pedal's thick, saturated, tight tone^[22] and the extreme sounds the pedal was able to produce thanks to its powerful EQ controls made the MT-2 divisive both upon its release and throughout its ongoing production.^[26] Despite this, the pedal has found fans in metal and other genres, including Prince^[26] and Joe Bonamassa.^[27]

The Metal Zone has sold over a million units, making it the company's best-selling pedal behind only the DS-1.^[22]

The Shredmaster was the high-gain model of a trio of pedals—including the Bluesbreaker and Drivemaster—released by Marshall in 1991, superseding the brand's first overdrive pedal, the Guv'nor.^[28] While the Bluesbreaker and Drivemaster replicated the tones of specific Marshall amps, the Shredmaster was a distortion pedal and replaced the other two pedals' three-band EQ setup with controls for Bass, Treble, and Contour, the last of which altered the character of the midrange while enhancing low and high frequencies. With poor sales, the trio was discontinued one year after their release.^[29] Radiohead guitarist Jonny Greenwood is often cited as the Shredmaster's most famous player.^[30]

Marshall reissued the Shredmaster, Bluesbreaker, Drivemaster, and Guv'nor in 2023 as its Vintage Reissue series, in response to the pedals having become sought-after vintage gear despite their initial unpopularity.^[31]

MXR scored its first success with the Phase 90 and followed quickly with a trio of 1974 releases, including the Distortion +. MXR's pedals were notable for their small footprint, as effects pedals were typically housed in large enclosures at the time, and durability, since MXR was initially founded to address the issue of other manufacturers' pedals' unreliability. The Distortion + has found a wide range of fans, like Randy Rhoads in his work with Ozzy Osbourne,^[32] Jerry Garcia of the Grateful Dead,^[32] Bob Mould of Hüsker Dü,^[33] Dave Murray of Iron Maiden,^[34] and Thom Yorke of Radiohead.

Developed in 1978 with mass production beginning a year later,^[35] the Pro Co Rat was the first mass-produced distortion pedal. In the Rat, Pro Co's engineers sought to improve upon the earlier Fuzz Face and ultimately designed a pedal with, as Guitar World wrote, a "hard, aggressive sound and tight, focused clipping" that set the template for modern distortion circuits.^[4] Pro Co has released numerous versions of the Rat since its initial release, and its enduring popularity has spawned numerous clones and tributes from other pedal manufacturers like JHS Pedals and Wampler Pedals.

The King of Tone, released in 2005, was designed by former software engineer Mike Piera to create an improved version of the then-discontinued Marshall Bluesbreaker pedal. A two-sided pedal with independent controls and internal DIP switches to choose between boost, overdrive, and distortion modes, Piera started building the pedals by hand in Bethel, Connecticut and selling them online under the moniker "Analog.Man."^[36] The King of Tone initially sold slowly, but quickly developed a following after Piera appeared on the Youtube channel "That Pedal Show" in 2017. Orders soon reached 200 per day—far more than Piera could keep up with—and the King of Tone developed a famously years-long waiting list, while prices on the used market far exceeded the cost of a new pedal. To satisfy demand, Piera developed a single-sided variation, the Prince of Tone, that would be manufactured in China, but still in limited numbers that sold out quickly. In 2022, Analog.Man partnered with MXR to release a smaller-format, mass-produced version, the Duke of Tone, which in 2023 became MXR's bestselling pedal.^[36]

Vintage Guitar dubbed the King of Tone one of a few "holy grail" overdrives.^[37]

In 1995, Boss released the BD-2, an overdrive pedal aimed at blues players who sought to add distortion while maintaining their amp's signal clarity and dynamics.^[38] At the time, blues was experiencing a resurgence thanks to Eric Clapton and Gary Moore. The pedal has a clear, punchy tone and features a flatter EQ-curve for a more amp-like tone than similar pedals, like the Ibanez Tube Screamer,^[39] while at higher gain levels it takes on an "edgy, grinding" quality. The Blues Driver is also a common platform for modifications, with boutique pedal makers like Robert Keeley and Josh Scott offering popular modding services. Boss went on to collaborate with Scott on the Boss JB-2 Angry Driver, which combines the BD-2 and JHS Angry Charlie circuits into one pedal.^[38]

Notable players who use the BD-2 include Tom Morello of Rage Against the Machine and Billie Joe Armstrong of Green Day.^[39]

With the 1977 release of the OD-1 OverDrive, Boss sought to offer guitarists a way to achieve the sound of power amp distortion at lower volume levels on any amp, as the advent of hard rock popularized heavily distorted tones, and the first master volume amplifiers had only recently become available. The OD-1's "overdrive" referenced the pedal's asymmetrical-clipping, tube-like distortion,^[38] which stood in contrast to the brash sound of "fuzz" pedals on the market.^[40] The OD-1's layout was simple—with only "Level" and "OverDrive" controls. It was an immediate success, paving the way for future compact overdrive pedals. Within a few years, however, the pedal's voicing was considered overly "sweet," as rock music became more aggressive, and the fixed frequency limited its versatility. With the surging popularity of the OD-1-influenced Tube Screamer and its addition of a tone control, Boss began including a "Tone" knob on its pedals with the 1981 SD-1 and the OD-1 was discontinued in 1985.^[40] Boss continued the OverDrive line with the four-knob OD-2 Turbo OverDrive, produced from 1985 to 1995, and subsequently the three-knob OD-3, which is still in production.^[38]

The Super OverDrive was released in 1981 as Boss's second overdrive pedal, adding a tone control to the earlier OD-1 design, while continuing to replicate the sound of tube amp-style overdrive^[22] via an asymmetrical clipping circuit and an inherent midrange-focus, but with less bass roll-off.^[38] The asymmetrical clipping lent the pedal a more aggressive character compared to the rival Tube Screamer, and it became popular in the growing hard rock and heavy metal subgenres with guitarists frequently using it to boost already-overdriven amplifiers like the Marshall JCM800 into higher-gain sounds.^[40]

In 2021, Boss released a 40th anniversary edition of the pedal,^[22] with the original circuit having remained unchanged since its introduction. Guitar dubbed the pedal one of only a handful to ever achieve "truly iconic status."^[41]

The Overdrive 250 Preamp, released in the 1970s as part of DOD Electronics' initial lineup of pedals, was originally a slight circuit variation of the Distortion+ by MXR, DOD's most direct competitor in the US market.^[42] The two pedals differed primarily in the 250 Preamp's use of silicon diodes instead of the germanium diodes of the Distortion+, which made a significant difference in the two pedals' tone and feel given the overall simplicity of their designs. Following DOD's acquisition by Digitech in 1990, the 250 Preamp was reissued several times, including with the JRC4558 op-amp popularized by the Ibanez Tube Screamer. Digitech was later bought by Cor-Tek, the parent company of Cort Guitars, and in 2013 the 250 Preamp was reissued once again, this time as a more faithful replica of the original design.^[42]

With the 1996 release of the Full-Drive 2, Fulltone had the industry's biggest early success in boutique overdrives, with the FD2 a common sight on professional guitarists' pedalboards in the late 1990s.^[43] Described as picking up where the Ibanez Tube Screamer and Boss SD-1 left off, the FD2 features expanded tonal controls in a larger housing compared to other popular overdrives, with a separate boost footswitch and multiple clipping options to alter the pedal's midrange character and compression.^[43] Guitar World dubbed the Full-Drive 2 a "Tube Screamer killer," praising it for emphasizing desirable midrange frequencies while offering a larger pallet of overdrive textures.^[44] The Full-Drive 2 has gone through multiple iterations, including a popular MOSFET version. Fulltone rebooted the pedal in 2018 with the Full-Drive 2 V2, which swaps the boost for a second overdrive channel and adds further clipping options.^[45]

In 2004, Fulltone released the Obsessive Compulsive Drive (OCD), which was designed as "an open-sounding distortion pedal with decent headroom to more faithfully emulate a driven tube amp,"^[46] with a circuit similar to the earlier Voodoo Labs Overdrive, itself a variation of the Ibanez Tubescreamer.^[46] An op amp-based pedal, the OCD has gone through multiple iterations, with changes from versions 1.1 to 1.7 being generally subtle alterations of the pedal's EQ response. Version 2 brought more noticeable changes, with a new output buffer, a 2N5457 JFET transistor input stage, and the option to use a new type of switching, enhanced bypass, instead of true bypass.^[46] After the first iteration, the drive pot's value was increased for a more "dramatic" distortion, and an asymmetric 1N34 germanium diode was later added to shift the character of the clipping.^[46]

The OCD was dubbed by Music Radar "one of the most legendary overdrives ever made."^[47]

Alfonso Hermida was an aerospace engineer with NASA in 1998—with a side job repairing effects pedals—when he first heard Robben Ford's rendition of "Golden Slumbers."^[48] Inspired to capture the tone he heard, Hermida spent years working on pedal designs, only later finding out about Ford and his connection to Dumble Amplifiers. In 2003, Hermida sent Ford his first finalized design, the Mosferatu, but it had more gain than Ford required, as the amount featured in "Golden Slumbers," which the Mosferatu replicated, was atypical for Ford. Hermida returned to an earlier attempt at capturing Ford's tone, a design with less gain and a greater focus on dynamics, and sent it to him. The pedal initially had three knobs, with Hermida later adding a fourth, "Voice," which altered the gain and bass response in tandem.^[48]

In 2004, Hermida officially released his pedal, the Zendrive, to acclaim. Premier Guitar praised the pedal for achieving the "smoother-than-smooth, violin-like lead tones" characteristic of Ford's amp of choice, the Dumble Overdrive Special, a famously expensive and exclusive amplifier.^[49] The Zendrive would reach similar status, with the pedal being made in limited quantities and used prices reaching over a thousand dollars.^[50] Ford himself is known to use a Zendrive with a clean Fender Twin.^[48] Struggling to keep up with demand, Hermida partnered with the company Lovepedal in 2013 to take over Zendrive manufacturing. Despite this, the Zendrive remains rare on the pedal market.^[50]

By the late 1970s, Ibanez—mostly known for producing Fender, Gibson, and Rickenbacker copies—wished to start producing overdrive pedals to compete with the Boss OD-1.^[51] The task was given to pickup manufacturer Nisshin (which sold products under the brand name Maxon) and designer Susumu Tamura. The design of the early TS-808 Tube Screamer was nearly identical to the OD-1, but relied on symmetrical clipping to avoid Boss' patent on solid-state asymmetrical clipping, while adding a tone control. Multiple iterations of the Tube Screamer followed, most notably the TS9, which replaced the TS-808 in 1982.^[51] Tube Screamers are characterized by a smooth distortion, with a strong increase in midrange frequencies and a cut in bass. This more focused tone became popular with blues, rock, and metal players, being used by many to create their signature sound.^[52][53] According to Premier Guitar, given the Tube Screamer's enduring popularity and influence, "no single pedal has had a greater impact on musical expression or played as important a role in the development of effects modification."^[51]

The Klon Centaur, made by American engineer Bill Finnegan, was released in 1994 with the aim of recreating the harmonically rich distortion of a guitar amplifier at a high volume.^[54] Finnegan wanted a "big, open" sound, with a "hint of tube clipping", that would not sound like a pedal was being used.^[54] He was quickly overwhelmed with orders, each taking 12–14 weeks, as Finnegan handmade the pedals himself. Deciding the profit margin was not sustainable, Finnegan discontinued the original Centaur in 2008, having produced 8,000 units. He later contracted out the manufacturing of a revised design, the Klon KTR. By 2019, used Centaurs sold for between $1,900 and US$2,500.^[55] According to Guitar.com, which named the Centaur one of the industry's greatest effect pedals, "The Klon Centaur is either the greatest, most useful overdrive ever made, or the worst example of guitarists losing all sense of perspective about how much good tone should cost."^[55]

The Klon Centaur has been used by guitarists including Jeff Beck, John Mayer, Joe Perry (of Aerosmith), Nels Cline (of Wilco), Matt Schofield, and Ed O'Brien (of Radiohead).^[54][56]

Launched in 1991 alongside the Drivemaster and Shredmaster, the Bluesbreaker overdrive was Marshall's attempt at recreating the tone of Marshall's own 1962 "Bluesbreaker" combo, nicknamed for its use by Eric Clapton when he played with John Mayall & The Bluesbreakers. While exceeding at adding subtle grit to a clean amp, the pedal failed to capture the tone of its namesake amp and was not a success during its limited initial production run. This changed years later when John Mayer started using a Bluesbreaker on his pedalboard, reigniting industry interest in it. Many pedal makers developed modified recreations of the original circuit, most notably Analog.Man's King of Tone. In 2023, Marshall reissued the Bluesbreaker, Drivermaster, and Shredmaster, as well as the earlier Guv'nor, as part of their Vintage Reissue series.^[57]

The Guv'nor, released in 1988, was Marshall's first overdrive pedal. Guitar.com credited the Guv'nor as the first "Marshall-in-a-box" (MIAB) pedal, a type of overdrive pedal that specifically seeks to replicate the sound of a cranked Marshall amp, typically a Plexi or JCM800.^[58] The Guv'nor features a three-band EQ—typical for amplifiers but not overdrive or distortion pedals—lending the pedal greater tonal versatility. The pedal also sports an effects loop, a rare feature for a pedal, and one Guitar.com dubbed "infamously pointless."^[58] Notable players include Gary Moore, with the pedal visible in artwork for his album Still Got the Blues.^[59]

The Guv'nor was discontinued in 1991 to make way for the launch of the Bluesbreaker, Shredmaster, and Drivemaster, the latter of which featured a revised Guv'nor circuit in new housing and without the effects loop. The Drivemaster in turn gained fans like Jeff Buckley and Dan Hawkins.^[59] Long after leaving the market, the Guv'nor circuit became popular with boutique pedal makers, with the circuit forming the basis of a wave of successful MIABs like the JHS Angry Charlie. Marshall relaunched the Guv'nor in 2023 as part of its Vintage Reissue series, which sought to take advantage of the four short-lived pedals having become collector's items.^[59]

The ODR-1 was created for the German brand Nobels by Kai Tachibana, who was dissatisfied with the strong increase in middle frequencies and decrease in bass common in other overdrive pedals. Sometimes referred to as "the other green overdrive," the ODR-1 and its fuller sound became a favorite pedal for Nashville session players like Tom Bukovac and Tim Pierce. Besides its unique, more balanced EQ curve, the ODR-1 eschews the conventional tone knob, which cuts or boosts treble frequencies, for a "Spectrum" control that simultaneously boosts/cuts both highs and lower-mids as the knob is turned.^[60] Original '90s ODR-1s have been listed on the secondhand market for as much as $2,000.^[61]

Cochrane first produced the Tim overdrive, one of the first boutique overdrive pedals, which became popular for its open, uncompressed tone with expanded EQ options. However, as the pedal was quite large, Cochrane released a smaller, four-knob option, the Timmy, which quickly surpassed the Tim in popularity. Guitar World places the Timmy in the Tube Screamer "family tree," while noting it does not have the Tube Screamer's characteristic mid-hump and is less compressed at lower gain levels. In the boutique market, the Timmy's transparent character and Volume/Gain/Bass/Treble control layout has been widely copied. Despite the pedal's success, Cochrane has continued to build the pedals himself and sells them at a reasonable price-point; Cochrane additionally assists the DIY community in creating Timmy-style pedals.^[62]

In 2020, Cochrane partnered with MXR to release a smaller format, mass-produced version of the Timmy.

• Boss' notable pedals
• Treble booster