The Pro Co "The RAT" is a distortion pedal produced by Pro Co Sound. The original RAT was developed in the basement of Pro Co's Kalamazoo, Michigan facility in 1978. [1] Numerous variations of the original RAT pedal are still being produced today, and it has become the 8th best selling guitar pedal of all time. [2]
The pedal has changed in appearance over the years, but its tone has remained largely the same. Pro Co has also introduced variations of the RAT, including the Turbo RAT and the You Dirty RAT, among others.
The origins of the Pro Co "The RAT" can be traced back to the mid-1970s, when Pro Co engineers, Scott Burnham and Steve Kiraly repaired and hot-rodded existing distortion pedals, such as the Dallas Arbiter Fuzz Face. Burnham decided he could build a superior product from the ground up, and designed what would become "The RAT" pedal. Burnham began work on his circuit as early as 1974, right around the same time hard clipping distortion circuits were starting to enter the market. While experimenting with his circuit however, he accidentally used the wrong value resistor to bias the operational amplifier, driving it into heavy distortion. "Opamp distortion" as it has come to be known was a completely novel idea at the time and, combined with the diode clipping section, allowed for much more aggressive distortion than was available at the time. Author Pagan Kennedy describes Burnham's invention as follows: [3]
"One day, as he was soldering parts, he picked up a resistor of the wrong size -this was his lucky mistake- and attached it to a circuit board. The machine began shrieking and moaning. And that's how he heard a new sound; it was beautiful, haunting, ugly, and full of soul. He immediately recognized this as a major discovery, and he built that sound into a distortion pedal he named the Rat. Attached to a guitar, the Rat turned every note into a blast of outrage".
In 1978, "The RAT", named because of the rat infested basement in which it was designed, [4] was being built as a custom-order product. [5] Only twelve of these pedals (including one prototype), commonly referred to as the "Bud Box" RAT, were produced. Each pedal was built in a standard project box, hand painted, and hand drilled. In 1979, Pro Co began mass-producing them. [5] This iteration was built in a custom designed, rectangular sheet-metal enclosure, with an L-shaped removable top/back section giving access to the internals. The top panel was labeled with Pro Co Sound "The RAT" and the three control knobs as Distortion, Tone and Volume. Between 1979 and 1980 there were several cosmetic changes to the pedal as Pro Co worked to source knobs and print the labels on the pedal, but the circuit remained largely unchanged. In 1981 the Rat saw its first circuit change. The tone control, which allowed the user to lower the volume of the treble frequencies as they turned it counterclockwise, was reversed to turn the treble down as the knob is turned clockwise. From an electrical standpoint, this change made no difference, but it is believed that the change was made through user feedback in an attempt to make the users perceive the effect as less harsh. [4]
In 1983, Pro Co switched to a smaller, U-shaped enclosure.Finally, in 1988, the RAT2 was introduced, which included an on/off LED that utilized a new "millenium bypass circuit", which has become the industry standard for pedal switching circuits. [4] The screen printed labels were replaced with glow in the dark mylar. Various RAT2 circuit board layouts and wiring configurations have surfaced in the last few years, including the noted "RAT3 version A and B" all under the RAT2 moniker. The RAT2 model is still available today, but in 2008 production moved to China and is now manufactured by Neutrik for Pro Co Sound. In 2019 Pro Co switched to an industry standard PSA adapter from their 1/8" adapter. Despite the high number of Rats released throughout the years, the circuit has remained very similar to the original schematic.
Other models of RAT products include: [5]
The Pro Co "The RAT" is a distortion pedal with a quite simple circuit, which can be broken down into four simpler blocks: distortion stage, tone control, output stage, and power supply. [5] All except the power supply directly interact with the guitar signal. The signal enters into the pedal, travels through a bandpass filter that filters out high and low frequency content from the signal.
It then moves on to the gain stage, which is based around a single opamp, originally the Motorola LM308 (switched to Texas Instruments OP07DP around 2002–2003). The distortion is produced using a variable gain circuit with diodes shorting the output to ground at a certain voltage level to produce hard clipping of the input waveform. At lower gain levels the distortion is produced entirely through the diodes, but at higher gain levels the opamp begins to distort as well. Originally, 1N914 diodes were used, which were later replaced with 1N4148 since RAT2. The 'Turbo RAT' pedal uses red LEDs for this purpose (red LEDs have about a twice as high forward voltage as the original silicon diodes), while the 'You Dirty RAT' pedal uses 1N34A germanium diodes (clipping at a much lower forward voltage). [5] [6]
The distortion stage is followed by a passive "reverse" tone filter and volume control.
This circuit has remained almost entirely untouched throughout the manufacture of the RAT and RAT2. Other versions of the RAT are near identical to the RAT2 except for changes to the clipping diodes, different enclosures, or the addition of new controls.
The RAT is a popular pedal for modifying. Some of the possible modifications include:
Because of the RAT's popularity, numerous large and small pedal designers and manufacturers have attempted to replicate its sound as 'clones' or in new designs. Often the goal of these 'clones' is to capture the sound of vintage RATS at a more affordable price point. Many RAT clones allow users to switch between the different RAT circuits (Turbo, standard, etc.) or between eras (Whiteface, LM308 Chip, Big box...). The simplicity of the circuit has also made it popular among pedal-kit manufacturers for first-time builders. Some examples of RAT 'clones' are:
An envelope detector is an electronic circuit that takes a (relatively) high-frequency signal as input and outputs the envelope of the original signal.
Danelectro is a brand of musical instruments and accessories that was founded in Red Bank, New Jersey, in 1947. The company is known primarily for its string instruments that employed unique designs and manufacturing processes. The Danelectro company was sold to the Music Corporation of America (MCA) in 1966, moved to a much larger plant in Neptune City, New Jersey, and employed more than 500 people. Nevertheless, three years later Danelectro closed its plant.
Boss is a manufacturer of effects pedals for electric guitar and bass guitar. It is a division of the Roland Corporation, a Japanese manufacturer that specializes in musical equipment and accessories. For many years Boss has manufactured a wide range of products related to effects processing for guitars, including "compact" and "twin" effects pedals, multi-effect pedals, electronic tuners and pedal boards. In more recent times, Boss expanded their product range by including digital studios, rhythm machines, samplers and other electronic music equipment. They also are now manufacturing solid-state amplifiers and speaker heads such as the Waza and the Katana. Both feature multi-effects units meant to emulate Boss' classic effects pedals.
Marshall Amplification is a British company that designs and manufactures music amplifiers and speaker cabinets. Founded in London by shop owner and drummer Jim Marshall, the company is based in Bletchley, Milton Keynes, England. Since March 2023, Marshall Amplification has been one of several divisions of the Swedish conglomerate, the Marshall Group.
Scholz Research & Development, Inc. was the name of the company founded by musician and engineer Tom Scholz to design and manufacture music technology products.
Electro-Harmonix is a New York City-based company that makes electronic audio processors and sells rebranded vacuum tubes. The company was founded by Mike Matthews in 1968. It is best known for a series of guitar effects pedals introduced in the 1970s and 1990s. EHX also made a line of guitars in the 1970s.
The Boss DS-1 is a distortion pedal for guitar, manufactured by the Roland Corporation under the brand name Boss since 1978. The first distortion effects unit made by Boss, it has become a classic effect, used by many notable guitar players.
Octave effect boxes are a type of special effects unit which mix the input signal with a synthesized signal whose musical tone is an octave lower or higher than the original. The synthesised octave signal is derived from the original input signal by halving (octave-down) or doubling (octave-up) the frequency. This is possible due to the simple two-to-one relationship between the frequencies of musical notes which are separated by an octave. One of the first popular musicians to employ the octave effect was Jimi Hendrix, who also used a variety of other effects in his recordings and public performances. Hendrix used an octave-fuzz pedal known as the octavia.
The Ibanez Tube Screamer is a guitar overdrive pedal, made by Ibanez. The pedal has a characteristic mid-boosted tone popular with blues, rock and metal players. The Tube Screamer has been used by many guitarists to create their signature sound, and is one of the most successful, widely copied, and custom-modified ("modded") overdrive pedals in the history of the electric guitar.
The Fuzz Face is an effects pedal for electric guitar, used also by some electric bass players. It is designed to produce a distorted sound referred to as "fuzz", originally achieved through accident such as broken electrical components or damaged speakers.
Distortion and overdrive are forms of audio signal processing used to alter the sound of amplified electric musical instruments, usually by increasing their gain, producing a "fuzzy", "growling", or "gritty" tone. Distortion is most commonly used with the electric guitar, but may also be used with other electric instruments such as electric bass, electric piano, synthesizer and Hammond organ. Guitarists playing electric blues originally obtained an overdriven sound by turning up their vacuum tube-powered guitar amplifiers to high volumes, which caused the signal to distort. While overdriven tube amps are still used to obtain overdrive, especially in genres like blues and rockabilly, a number of other ways to produce distortion have been developed since the 1960s, such as distortion effect pedals. The growling tone of a distorted electric guitar is a key part of many genres, including blues and many rock music genres, notably hard rock, punk rock, hardcore punk, acid rock, grunge and heavy metal music, while the use of distorted bass has been essential in a genre of hip hop music and alternative hip hop known as "SoundCloud rap".
A treble booster is an effects unit used by guitarists to increase the high end of their tonal spectrum. Many units boost the overall volume as well. Treble boosters were commonly used by guitarists in the 1960s and 1970s. During the last couple of decades, their popularity has increased again and many clones and reissues of the classic circuits have become available.
Bass effects are electronic effects units that are designed for use with an electric bass and a bass amplifier, or for an upright bass and a bass amp or PA system. Bass effects are commonly available in stompbox-style pedals, which are metal or plastic boxes with a foot-operated pedal switch or button which turns the effect on and off. Most pedals also have knobs to control the tone, volume and effect level. Some bass effects are available in 19" rackmount units, which can be mounted in a road case. As well, some bass amplifiers have built-in effects, such as compression, overdrive or chorus.
The MXR Distortion + is a distortion pedal originally designed in the 1970s by MXR Innovations.
The Univox Super-Fuzz was a fuzzbox produced by the Univox company, primarily for use with the electric guitar or bass.
Tone Bender is the name of several fuzz distortion effect pedals.
The Big Muff Pi (π), often known simply as the Big Muff, is a "fuzzbox" effects 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. It is used by bassists as well, due to the Big Muff's squeaky frequency response.
Fuzz bass is a style of playing the electric bass or modifying its signal that produces a buzzy, distorted, overdriven sound, as the name implies. Overdriving a bass signal significantly changes the timbre, adds higher overtones (harmonics), increases the sustain, and, if the gain is turned up high enough, creates a "breaking up" sound characterized by a growling, buzzy tone.
The Klon Centaur is an overdrive pedal made by the American engineer Bill Finnegan between 1994 and 2008. Finnegan aimed to create a pedal that would recreate the harmonically rich distortion of a guitar amplifier at a high volume.
pro co rat.