Delay/Echo
Main article: Delay (audio effect)
A delay or echo pedal creates a copy of an incoming sound and slightly time-delays it, creating either a “slap” (single repetition) or an echo (multiple repetitions) effect. Delay pedals, which may use either analog or digital technology, can be used to create effects ranging from a subtle alteration of the original signal to drastically-altered sounds. Analog delays often are less flexible and not as “perfect” sounding as digital delays, but some Guitarists argue that analog effects produce “warmer” tones. Early delay devices used loops of magnetic tape to produce the time delay effect. U2’s Guitarist, The Edge, is known for his extensive use of delay effects. Some common Delay pedals are:

Boss DD-7 Digital Delay
Line 6 DL-4 Delay Modeler
Line 6 Echo Park
T-Rex Engineering’s Replica
Boss DD-20 Giga Delay
TC Electronic Nova Delay
Danelectro FAB Echo
Mxr M169 Carbon Copy Analog Delay
Another technology that is used in Delay units is a “feedback circuit”, consisting of a tracking oscillator circuit to hold a note of the last interval, and, after amplifying the signal, send it back to the input side of the delay. While it was first associated with Boss DF-2 Super Feedbacker & Distortion, currently, the signal feedback circuit is employed by other delay pedals. When used with the “hold” mode (As in Boss DD-3), this circuit will provide a sustain effect instead of simply a delay effect. While the selected note is being sustained, a Guitarist can use it as a pedal point to solo over.

Looping
Extremely long delay times form a looping pedal, which allows performers to record a phrase or passage and play along with it. This allows a solo performer to record an accompaniment, riff, or ostinato passage and then, with the looping pedal playing back this passage, perform solo improvisations over the accompaniment. The Guitarist can either creates the loop onstage, or create it before a show and store it for later use (as in playback).

Some examples of loops effects are:

Boss RC-2 Loop Station
DigiTech JamMan Looper
Electro-Harmonix 2880

Reverb
Main article: Reverb
Reverbration, or “reverb”, is the persistence of sound in a particular space after the original sound is removed. When sound is produced in a space, a large number of echoes build up and then slowly decay as the sound is absorbed by the walls and air, creating reverberation, or reverb. A plate reverb system uses an electromechanical transducer, similar to the driver in a loudspeaker, to create vibration in a plate of sheet metal. A pickup captures the vibrations as they bounce across the plate, and the result is output as an audio signal. A spring reverb system uses a transducer at one end of a spring and a pickup at the other, similar to those used in plate reverbs, to create and capture vibrations within a metal spring. Guitar amplifiers often use spring reverbs due to their simple and inexpensive construction. Spring reverberators were once widely used in semi-professional recording due to their modest cost and small size.

Due to quality problems and improved digital reverb units, spring reverberators are less-commonly provided in Guitar amplifiers. Digital reverb units use various signal processing algorithms in order to create the reverb effect. Since reverberation is essentially caused by a very large number of echoes, simple DSPs use multiple feedback delay circuits to create a large, decaying series of echoes that die out over time.

Examples of reverb pedals include:

DigiTech DigiDelay
Electro-Harmonix Holy Grail
Boss RV-5 Digital Reverb
Line 6 Verbzilla
Danelectro DJ-4 Corned Beef Reverb

Volume pedal
A volume pedal is a volume potentiometer that is tilted forward or back by foot. A volume pedal enables a musician to adjust the volume of their instrument while they are performing. Volume pedals can also be used to make the Guitar’s notes or chords fade in and out. This allows the percussive plucking of the strings to be softened or eliminated entirely, imparting a human-vocal sound. Volume pedals are also widely used with pedal steel Guitars in country music. It has also been used to great effect in rock music. While volume pedals made of molded plastic with a single mono input are much less expensive, the best quality, most expensive pedals are made of metal, and they have stereo inputs, smooth-rolling potentiometers and a “minimum” volume knob.

Some volume pedals are:

Ernie Ball Stereo Volume Pedal
Boss FV-50H Foot Volume
VOX V850 Volume Pedal

Auto-Volume/Envelope Volume
Just as an Auto-Wah is a version of a Wah pedal controlled by the signal’s dynamic envelope, there is an envelope-controlled version of a volume pedal. This is generally used to mimic automatically the sound of picking a note while the Guitar’s volume knob is turned down, then smoothly turning the knob up. This creates a sound similar to that which can be obtained on bowed stringed instruments such as the violin, in which the Guitar note or chord gradually “blossoms” out of the silence. This effect inverts the typical sound of a plucked instrument, in which notes or chords typically start with a strong attack, and then fade away.

An example is:

Boss SG-1 Slow Gear-discontinued product
Behringer SM-200 Slow Motion

Tremolo
Main article: Tremolo
Tremolo is a regular and repetitive variation in gain for the duration of a single note, which works like an auto-volume knob. It recreates the sound of rapidly turning the volume up and down, which creates a “shuddering” sound. This is a volume-related effects pedal. This effect is based on one of the earliest effects that were built into Guitar amplifiers.

Examples include:

Voodoo Lab Tremolo
Boss TR-2 Tremolo
Electro-Harmonix Pulsar
Line 6 Tap Tremolo

Compressor
Main article: Audio level compression
A compressor acts as an automatic volume control, progressively decreasing the output level as the incoming signal gets louder, and vice versa. It preserves the note’s attack rather than silencing it as with an Envelope Volume pedal. This adjustment of the volume for the attack and tail of a note evens out the overall volume of an instrument. Compressors can also change the behaviour of other effects, especially distortion. When applied to the Guitar, it can provide a uniformed sustained note; when applied to instruments with a normally short attack, such as drums or harpsichord, compression can drastically change the resulting sound. Compressors can also be used to smooth out the sound of a Guitar or bass Guitar. Another kind of compressor is the optical compressor, which uses a light source such as an LED or lamp to compress the signal.

Some compressor pedals are:

Boss CS-3 Compression Sustainer
MXR M-102 DynaComp
Line 6 Constrictor
T-Rex Engineering’s CompNova
Electro-Harmonix Black Finger (optical compressor)
Aphex Punch Factory Optical Compressor

Equalizer
Main article: Equalization
An equalizer adjusts the frequency response in a number of different frequency bands. A graphic equalizer (or “graphic EQ”) provides slider controls for a number of frequency region. Each of these bands has a fixed width (Q) and a fixed center-frequency, and as such, the slider changes only the level of the frequency band. The tone controls on Guitars, Guitar amps, and most pedals are similarly fixed-Q and fixed-frequency, but unlike a graphic EQ, rotary controls are used rather than sliders.

Most parametric EQ pedals (such as the Boss PQ-4) provide semi-parametric EQ. That is, in addition to level control, each band provides either a center frequency or Q width control. Parametric EQs have rotating controls rather than sliders.

Placement of EQ in a distortion signal processing chain affects the basic Guitar amp tone. Using a Guitar’s rotary tone control potentiometer is a form of pre-distortion EQ. Placing an EQ pedal before a distortion pedal or before a Guitar amp’s built-in preamp distortion provides preliminary control of the preamp distortion voicing. For more complete control of preamp distortion voicing, an additional EQ pedal can be placed after a distortion pedal; or, equivalently, the Guitar amp’s tone controls, after the built-in preamp distortion, can be used. An EQ pedal in the amp’s effects loop, or the amp’s tone controls placed after preamp distortion, constitutes post-distortion EQ, which finishes shaping the preamp distortion and sets up the power-tube distortion voicing.

As an example of pre-distortion EQ, Eddie Van Halen places a 6-band MXR EQ pedal before the Marshall amplifier head (pre-distortion EQ). Slash places a Boss GE-7, a 7-band EQ pedal, before his Marshall amp. This technique is similar to placing a Wah pedal before the amp’s preamp distortion and leaving the Wah pedal positioned part-way down, sometimes mentioned as “fixed wah,” (pre-distortion EQ), along with adjusting the amp’s tone controls (post-distortion EQ).

If a dummy load Guitar-amp configuration is used, an additional EQ position becomes available, between the dummy load and the final amplifier that drives the Guitar speaker. Van Halen used an additional EQ in this position. This configuration is commonly used with rackmount systems. Finally, an EQ pedal such as a 10-band graphic EQ pedal can be placed in the Insert jack of a mixer to replace the mixer channel’s EQ controls, providing graphical control over the miked Guitar speaker signal.

Equalization-related effects pedals include Wah, Auto-Wah, and Phase Shifter. Most EQ pedals also have an overall Level control distinct from the frequency-specific controls, thus enabling an EQ pedal to act as a configurable level-boost pedal. Some EQ pedals include:

MXR M-108 10-band Equalizer
Boss GE-7 Equalizer
Danelectro Fish ‘n Chips

Wah pedal
Main article: Wah-wah pedal
A wah-wah pedal is a foot-operated pedal, technically a kind of band-pass filter, which allows only a small portion of the incoming signal’s frequencies to pass. Rocking the pedal back and forth alternately allows lower and higher frequencies to pass through, the effect being similar to a person saying “wah”. The wah pedal, used with Guitar, is most associated with 1960s psychedelic rock and 1970s funk. During this period wah-wah pedals often incorporated a fuzzbox to process the sound before the wah-wah circuit, the combination producing a dramatic effect known as fuzz-wah.

Some wah-wah pedals include:

Dunlop Cry Baby
VOX V847 Wah
Budda BudWah Wah
Ibanez Wh10

Auto-Wah / Envelope Filter
Main article: Auto-wah
An auto-wah is a wah-wah pedal without a rocker pedal, controlled instead by the dynamic envelope of the signal. An auto-wah, also called more technically an envelope filter, uses the level of the Guitar signal to control the wah filter position, so that as a note is played, it automatically starts with the sound of a wah-wah pedal pulled back, and then quickly changes to the sound of a wah-wah pedal pushed forward, or the reverse movement depending on the settings. Controls include wah-wah pedal direction and input level sensitivity. This is an EQ-related effect and can be placed before preamp distortion or before power-tube distortion with natural sounding results. Auto-Wah pedals include:

Electro-Harmonix Q-Tron
MXR M-120 Auto Q
Keeley Electronics Nova Wah

Talk Box
Main article: Talk box
Early forms of the talk box, such as the Heil Talk Box, first appeared in Country Music circles in Nashville in the 1940′,s 1950’s, and 1960’s, by artist like swing band pedal steel player Alvino Rey, Link Wray (”Rumble”), Bill West, a Country Music steel Guitar player and husband of Dottie West, and Pete Drake, a Nashville mainstay on the pedal steel Guitar and friend of Bill West. Drake used it on his 1964 album Forever, in what came to be called his “talking steel Guitar.” The device used the Guitar amplifier’s output to drive a speaker horn that pushed air into a tube held in the player’s mouth, which filters and thereby shapes the sound leading to a unique effect. The singer and Guitarist Peter Frampton made this effect famous with hit songs such as “Do You Feel Like We Do” and “Show Me the Way,” as did Joe Walsh on “Rocky Mountain Way.” On Van Halen’s cover of “You Really Got Me” Eddie Van Halen uses a talk box. Newer devices, such as Danelectro’s Free Speech pedal, use a microphone and vocoder-like circuit to modulate the frequency response of the Guitar signal. Some Talk Boxes include: The Dunlop Heil Talk Box, Rocktron Banshee, and Peter Frampton’s own company,Framptone.

Distortion is an important part of an electric Guitar’s sound in many genres, particularly for rock, hard rock, and metal. A distortion pedal takes a normal electric Guitar signal and distorts the signal’s waveform by “clipping” the signal. There are several different types of distortion effects, each with distinct sonic characteristics. These include overdrive/distortion (or vacuum tube-style distortion), overdrive/crunch, fuzz, and hi-gain.

Overdrive Distortion
Overdrive distortion is a well-known distortion. While the general purpose is to emulate classic “warm-tube” sounds, distortion pedals such as the ones in this list can be distinguished from overdrive pedals in that the intent is to provide players with instant access to the sound of a high-gain Marshall amplifier such as the JCM800 pushed past the point of tonal breakup and into the range of tonal distortion known to electric Guitarists as “saturated gain.” Some Guitarists will use these pedals along with an already distorted amp or along with a milder overdrive effect to produce radically high-gain sounds. Although most distortion devices use solid-state circuitry, some “tube distortion” pedals are designed with preamplifier vacuum tubes. In some cases, tube distortion pedals use power tubes or a preamp tube used as a power tube driving a built-in “dummy load.” Pedals designed specifically for bass Guitar are also available. Some distortion pedals include:

MXR ZW44 Zakk Wylde
Pro Co Rat
Boss DS-1 Distortion
Marshall Guv’nor
Line 6 Dr. Distorto
T-Rex Engineering’s Bloody Mary
Digitech Hot Head
Danelectro FAB Distortion

Overdrive/Crunch
Some distortion effects provide an “overdrive” effect. Either by using a vacuum tube, or by using simulated tube modeling techniques, the top of the wave form is compressed, thus giving a smoother distorted signal than regular distortion effects. When an overdrive effect is used at a high setting, the sound’s waveform can become clipped, which imparts a gritty or “dirty” tone, which sounds like a tube amplifier “driven” to its limit. Used in conjunction with an amplifier, especially a tube amplifier, driven to the point of mild tonal breakup short of what would be generally considered distortion or overdrive, or along with another, stronger overdrive or distortion pedal, these can produce extremely thick distortion sounds much like those used by Carlos Santana or Eddie Van Halen. Today there is a huge variety of overdrive pedals, and some of them are:

Ibanez Tube Screamer (TS-9 and TS-808)
Boss SD-1 Super Overdrive
Boss BD-2 Blues Driver
Boss OD-3 Overdrive
Line 6 Crunchtone
DigiTech Bad Monkey
Danelectro FAB Overdrive

Fuzz
Main article: Fuzzbox
Fuzz was originally intended to recreate the classic 1960’s tone of an overdriven tube amp combined with torn speaker cones. Oldschool Guitar players (like Link Wray) would use a screwdriver to poke several holes through the paperboard part of the Guitar amp speaker to achieve a similar sound. Since the original designs, more extreme fuzz pedals have been designed and produced, incorporating octave-up effects, oscillation, gating, and greater amounts of distortion.

Some fuzzbox pedals include:

Z.Vex Fuzz Factory
Dallas Arbiter Fuzz Face
Electro-Harmonix Big Muff
Electro-Harmonix Little Big Muff
Boss FZ-5 Fuzz

Hi-Gain
Hi-Gain (descended from the more generic electric Guitar amplification term high-gain) is the sound most used in Heavy Metal. High gain in normal electric Guitar playing simply references a thick sound produced by heavily overdriven amplifier tubes, a distortion pedal, or some combination of both–the essential component is the typically loud, thick, harmonically rich, and sustaining quality of the tone. However, the Hi-Gain sound of modern pedals is somewhat distinct from, although descended from, this sound. The distortion often produces sounds not possible any other way. Many extreme distortions are either hi-gain or the descendents of such. The Mesa Boogie Triple Rectifier Series of amps are an example.

Some Hi-Gain Pedals Include:

Boss ML-2 Metal Core
Boss MT-2 Metal Zone
Electro-Harmonix Metal Muff
DigiTech Death Metal
Danelectro FAB Metal
MXR Dime Distortion
Line 6 Uber Metal

Power-tube pedal
A Power-Tube pedal contains a power tube and optional dummy load, or a preamp tube used as a power tube. This allows the device to produce power-tube distortion independently of volume; therefore, power-tube distortion can be used as an effects module in an effects chain. Some examples are:

Ibanez Tube King
various Tonebone distortion pedals
Damage Control pedals
Electro-Harmonix English Muffin’

Power attenuator
Main article: Power attenuator (Guitar)
A power Attenuator enables a player to obtain power-tube distortion independently of listening volume. A power attenuator is a dummy load placed between the Guitar amplifier’s power tubes and the Guitar speaker, or a power-supply based circuit to reduce the plate voltage on the power tubes. Examples of power attenuators are the Marshall PowerBrake, THD HotPlate and Weber MASS.