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107-418: 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 Tube Screamer has

214-453: A hiss filter used in audio , anti-aliasing filters for conditioning signals before analog-to-digital conversion , digital filters for smoothing sets of data, acoustic barriers, blurring of images, and so on. The moving average operation used in fields such as finance is a particular kind of low-pass filter and can be analyzed with the same signal processing techniques as are used for other low-pass filters. Low-pass filters provide

321-408: A compressed sound that is often described as "warm" and "dirty", depending on the type and intensity of distortion used. The terms distortion and overdrive are often used interchangeably; where a distinction is made, distortion is a more extreme version of the effect than overdrive . Fuzz is a particular form of extreme distortion originally created by guitarists using faulty equipment (such as

428-496: A "dirty" or "gritty" tone. When asymmetrical, it produces both even and odd harmonics. Electronically, this is usually achieved by either amplifying the signal to a point where it is clipped by the DC voltage limitation of the power supply rail, or by clipping the signal with diodes. Many solid-state distortion devices attempt to emulate the sound of overdriven vacuum valves using additional solid-state circuitry. Some amplifiers (notably

535-531: A DI jack on the guitar amp, or from the Line Out jack of a power attenuator. The output transformer sits between the power valves and the speaker, serving to match impedance . When a transformer's ferromagnetic core becomes electromagnetically saturated a loss of inductance takes place, since the back E.M.F. is reliant on a change in flux in the core. As the core reaches saturation, the flux levels off and cannot increase any further. With no change in flux there

642-434: A TS9 model, his favorite Ibanez Tube Screamer. Arctic Monkeys frontman Alex Turner Also used an Ibanez Tube Screamer for the band’s second Album: Favourite Worst Nightmare Distortion (music) The effects alter the instrument sound by clipping the signal (pushing it past its maximum, which shears off the peaks and troughs of the signal waves), adding sustain and harmonic and inharmonic overtones and leading to

749-487: A change in the input samples ( x 1 , x 2 , … , x n ) {\displaystyle (x_{1},\,x_{2},\,\ldots ,\,x_{n})} ; the system has more inertia . This filter is an infinite-impulse-response (IIR) single-pole low-pass filter. Finite-impulse-response filters can be built that approximate the sinc function time-domain response of an ideal sharp-cutoff low-pass filter. For minimum distortion,

856-438: A clear, undistorted bass sound, professional bass players in these genres use high-powered amplifiers with a lot of " headroom " and they may also use audio compressors to prevent sudden volume peaks from causing distortion. In many cases, musicians playing stage pianos or synthesizers use keyboard amplifiers that are designed to reproduce the audio signal with as little distortion as possible. The exceptions with keyboards are

963-401: A clipping "overdriven" condition; as such, the musician will get the distortion from the fuzz which is then distorted further by the amp. During the 1990s, some Seattle grunge guitarists chained together as many as four fuzz pedals to create a thick " wall of sound " of distortion. In some modern valve effects, the "dirty" or "gritty" tone is actually achieved not by high voltage, but by running

1070-536: A completely clean amplifier to generate the whole overdrive/distortion effect. With care—and with appropriately chosen pedals—it is possible to "stack" multiple overdrive/distortion pedals together, allowing one pedal to act as a 'boost' for another. Fuzz boxes and other heavy distortions can produce unwanted dissonances when playing chords. To get around this, guitar players (and keyboard players) using these effects may restrict their playing to single notes and simple " power chords " (root, fifth, and octave). Indeed, with

1177-760: A computer by analyzing an RC filter's behavior in the time domain, and then discretizing the model. From the circuit diagram to the right, according to Kirchhoff's Laws and the definition of capacitance : where Q c ( t ) {\displaystyle Q_{c}(t)} is the charge stored in the capacitor at time t . Substituting equation Q into equation I gives i ( t ) = C d ⁡ v out d ⁡ t {\displaystyle i(t)\;=\;C{\frac {\operatorname {d} v_{\text{out}}}{\operatorname {d} t}}} , which can be substituted into equation V so that This equation can be discretized. For simplicity, assume that samples of

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1284-478: A different way. Power amplifier distortion may damage speakers. A Direct Inject signal can capture the power-tube distortion sound without the direct coloration of a guitar speaker and microphone. This DI signal can be blended with a miked guitar speaker, with the DI providing a more present, immediate, bright sound, and the miked guitar speaker providing a colored, remote, darker sound. The DI signal can be obtained from

1391-496: A distorted or "dirty" tone. Later, around 1945, Western swing guitarist and member of the Bob Wills band, Junior Barnard , began experimenting with a rudimentary humbucker pick-up and a small amplifier to obtain his signature "low-down and dirty" bluesy sound which allowed for more "fluid and funky" chords. Many electric blues guitarists, including Chicago bluesmen such as Elmore James and Buddy Guy , experimented to get

1498-602: A drive knob, a tone knob, and a level knob. The drive knob adjusts gain (which can affect the amount of distortion), the tone knob adjusts treble and the level knob adjusts the output volume of the pedal. The Tube Screamer name refers to the pedal's ability to drive the preamp section of a tube amplifier , resulting in more gain from the amp itself. The pedal also provides a slight boost to mid-range frequencies, helping to reduce muddiness by cutting bass frequencies when used in this way. Some guitarists prefer this sort of equalization, as it helps to keep their sound from getting lost in

1605-419: A filter is generally represented using a Bode plot , and the filter is characterized by its cutoff frequency and rate of frequency rolloff . In all cases, at the cutoff frequency, the filter attenuates the input power by half or 3 dB. So the order of the filter determines the amount of additional attenuation for frequencies higher than the cutoff frequency. On any Butterworth filter, if one extends

1712-438: A folk or bluegrass style. Low-pass filter A low-pass filter is a filter that passes signals with a frequency lower than a selected cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency. The exact frequency response of the filter depends on the filter design . The filter is sometimes called a high-cut filter , or treble-cut filter in audio applications. A low-pass filter

1819-401: A fuzzy and somewhat distorted sound gained widespread popularity after guitarist Dave Davies of The Kinks used a razor blade to slash his speaker cones for the band's single " You Really Got Me ". In May 1965 Keith Richards used a Maestro FZ-1 Fuzz-Tone to record " (I Can't Get No) Satisfaction ". The song's success greatly boosted sales of the device, and all available stock sold out by

1926-400: A guitar solo with warm overtones created by his small valve amplifier . Pat Hare produced heavily distorted power chords on his electric guitar for records such as James Cotton 's " Cotton Crop Blues " (1954) as well as his "I'm Gonna Murder My Baby" (1954), creating "a grittier, nastier, more ferocious electric guitar sound," accomplished by turning the volume knob on his amplifier "all

2033-453: A guitar sound that paralleled the rawness of blues singers such as Muddy Waters and Howlin' Wolf , replacing often their originals with the powerful Valco "Chicagoan" pick-ups, originally created for lap-steel, to obtain a louder and fatter tone. In early rock music , Goree Carter 's "Rock Awhile" (1949) featured an over-driven electric guitar style similar to that of Chuck Berry several years later, as well as Joe Hill Louis ' " Boogie in

2140-476: A harder attack. Much has been made of the operational amplifier chips used in the various versions of the Tube Screamer pedal, and several "fairy tales" about the merits of these devices have been written on the subject. The JRC4558D chip is well-regarded by some. The (RC)4558 is a low priced, general purpose dual operational amplifier, introduced mid 70s by Texas Instruments as an "improved" version of

2247-652: A housing very similar to the TS-808/TS808. The green OD-II had a circuit similar to the TS808; however, the OD and OD-II had a more distorted circuit. Once Ibanez discontinued the 9 series pedals, they introduced the "Master" or "L" series. These were only made in 1985, and did not have the Tube Screamer in the line-up. A rare and valuable version of the Tube Screamer was the ST9 Super Tube Screamer , which

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2354-519: A low-pass filter is found by solving the response to the simple low-pass RC filter. Using Kirchhoff's Laws we arrive at the differential equation If we let v in ( t ) {\displaystyle v_{\text{in}}(t)} be a step function of magnitude V i {\displaystyle V_{i}} then the differential equation has the solution where ω 0 = 1 R C {\displaystyle \omega _{0}={1 \over RC}}

2461-504: A misaligned valve (tube); see below), which has been emulated since the 1960s by a number of "fuzzbox" effects pedals. Distortion, overdrive, and fuzz can be produced by effects pedals , rackmounts , pre-amplifiers , power amplifiers (a potentially speaker-blowing approach), speakers and (since the 2000s) by digital amplifier modeling devices and audio software . These effects are used with electric guitars , electric basses ( fuzz bass ), electronic keyboards , and more rarely as

2568-461: A musical effect, there are some musical styles and musical applications where as little distortion as possible is sought. When DJs are playing recorded music in a nightclub , they typically seek to reproduce the recordings with little or no distortion. In many musical styles, including pop music , country music and even genres where the electric guitars are almost always distorted, such as heavy metal, punk and hard rock, sound engineers usually take

2675-411: A number of steps to ensure that the vocals sounding through the sound reinforcement system are undistorted (the exception is the rare cases where distortion is purposely added to vocals in a song as a special effect, mainly in industrial music genres). Sound engineers prevent unwanted, unintended distortion and clipping using a number of methods. They may reduce the gain on microphone preamplifiers on

2782-420: A pedal sound different from the "discrete" transistorized 60's fuzzes. The overdrive is produced using two silicon diodes in anti-parallel arrangement into the negative feedback circuit of an operational amplifier ("op-amp") circuit, to produce soft, symmetrical distortion of the input waveform. When the output exceeds the forward volt drop of the diodes the amplifier gain is much lower, effectively limiting

2889-568: A power-valve distortion pedal. Such effects units can use a preamp valve such as the 12AX7 in a power-valve circuit configuration (as in the Stephenson's Stage Hog), or use a conventional power valve, such as the EL84 (as in the H&;K Crunch Master compact tabletop unit). However, because these are usually placed before the pre-amplifier in the signal chain, they contribute to the overall tone in

2996-491: A signal by the rectangular function in the frequency domain or, equivalently, convolution with its impulse response , a sinc function , in the time domain. However, the ideal filter is impossible to realize without also having signals of infinite extent in time, and so generally needs to be approximated for real ongoing signals, because the sinc function's support region extends to all past and future times. The filter would therefore need to have infinite delay, or knowledge of

3103-410: A silicon and a germanium device), or more than two diodes in various arrangements, or modified tone circuits. It is also used by many metal guitarists before the lead channel of the high gain amps to make distortion more focused and to cut the low end. Notable modifiers of the pedal include Robert Keeley of Keeley Electronics and Mike Piera of AnalogMan. Joan Jett used a TS9DX model. Ola Englund used

3210-407: A simple but effective post-distortion equalization circuit with a first-order high-pass shelving filter that "is linearly dependent on its gain", an approach called "progressivity". The overdrive stage is followed by a simple low-pass filter and active tone control circuit and volume control, using the second op-amp available on-chip. The circuit uses transistor buffers at both the input and

3317-542: A small recording or rehearsal space, many solutions have emerged that in some way divert some of this power valve output from the speakers, and allow the player to generate power valve distortion without excessive volume. These include built-in or separate power attenuators and power-supply-based power attenuation, such as a VVR, or Variable Voltage Regulator to drop the voltage on the valves' plates, to increase distortion whilst lowering volume. Guitarists such as Eddie Van Halen have been known to use variacs before VVR technology

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3424-660: A smoother form of a signal, removing the short-term fluctuations and leaving the longer-term trend. Filter designers will often use the low-pass form as a prototype filter . That is a filter with unity bandwidth and impedance. The desired filter is obtained from the prototype by scaling for the desired bandwidth and impedance and transforming into the desired bandform (that is, low-pass, high-pass, band-pass or band-stop ). Examples of low-pass filters occur in acoustics , optics and electronics . A stiff physical barrier tends to reflect higher sound frequencies, acting as an acoustic low-pass filter for transmitting sound. When music

3531-540: A special effect with vocals. While distortion is often created intentionally as a musical effect, musicians and sound engineers sometimes take steps to avoid distortion , particularly when using PA systems to amplify vocals or when playing back prerecorded music. The first guitar amplifiers were relatively low-fidelity , and would often produce distortion when their volume ( gain ) was increased beyond their design limit or if they sustained minor damage. From 1935, Western swing guitarist Bob Dunn began experimenting with

3638-418: A strong influence on the distortion created by that stage. The output level of the guitar's pickups, the setting of the guitar's volume knob, how hard the strings are plucked, and the use of volume-boosting effects pedals can drive this stage harder and create more distortion. During the 1980s and 1990s, most valve amps featured a "master volume" control, an adjustable attenuator between the preamp section and

3745-418: A tone input progressively begins to resemble a square wave which has odd number harmonics. This is generally described as sounding "harsh". Distortion and overdrive circuits each 'clip' the signal before it reaches the main amplifier (clean boost circuits do not necessarily create 'clipping') as well as boost signals to levels that cause distortion to occur at the main amplifier's front end stage (by exceeding

3852-409: A weak instrument signal to a level that can drive the power amplifier. It often also contains circuitry to shape the tone of the instrument, including equalization and gain controls. Often multiple cascading gain/clipping stages are employed to generate distortion. Because the first component in a valve amplifier is a valve gain stage, the output level of the preceding elements of the signal chain has

3959-432: Is a non-linear process that produces frequencies not originally present in the audio signal . These frequencies can be harmonic overtones, meaning they are whole number multiples of one of the signal's original frequencies, or "inharmonic", resulting from general intermodulation distortion . The same nonlinear device will produce both types of distortion, depending on the input signal. Intermodulation occurs whenever

4066-401: Is a distortion process known as "volume adjustment", which involves distorting the amplitude of a sound wave in a proportional (or 'linear') way in order to increase or decrease the volume of the sound without affecting the tone quality. In the context of music, the most common source of (nonlinear) distortion is clipping in amplifier circuits and is most commonly known as overdrive. Clipping

4173-513: Is a low-pass filter used to reduce the amount of treble in the sound. An integrator is another time constant low-pass filter. Telephone lines fitted with DSL splitters use low-pass filters to separate DSL from POTS signals (and high-pass vice versa), which share the same pair of wires ( transmission channel ). Low-pass filters also play a significant role in the sculpting of sound created by analogue and virtual analogue synthesisers . See subtractive synthesis . A low-pass filter

4280-483: Is an exact reconstruction (0% error). This is the reconstructed output for a time-invariant input. However, if the input is time variant , such as v in ( t ) = V i sin ⁡ ( ω t ) {\displaystyle v_{\text{in}}(t)=V_{i}\sin(\omega t)} , this model approximates the input signal as a series of step functions with duration T {\displaystyle T} producing an error in

4387-662: Is easily obtained by sampling the step input response above at regular intervals of n T {\displaystyle nT} where n = 0 , 1 , . . . {\displaystyle n=0,1,...} and T {\displaystyle T} is the time between samples. Taking the difference between two consecutive samples we have Solving for v o u t ( n T ) {\displaystyle v_{\rm {out}}(nT)} we get Where β = e − ω 0 T {\displaystyle \beta =e^{-\omega _{0}T}} Using

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4494-706: Is impractical; instead, most pedals use solid-state transistors, op-amps and diodes. Classic examples of overdrive/distortion pedals include the Boss OD series (overdrives), the Ibanez Tube Screamer (an overdrive), the Electro-Harmonix Big Muff Pi (a fuzz box) and the Pro Co RAT (a distortion). Typically, "overdrive" pedals are designed to produce sounds associated with classic rock or blues, with "distortion" pedals producing

4601-445: Is known as "sag", and is sought-after by some electric guitarists. Sag only occurs in class-AB amplifiers . This is because, technically, sag results from more current being drawn from the power supply, causing a greater voltage drop over the rectifier valve. Class AB amplifiers draw the most power at both the maximum and minimum point of the signal, putting more stress on the power supply than class A, which only draws maximum power at

4708-418: Is no back E.M.F. and hence no reflected impedance. The transformer and valve combination then generate large 3rd order harmonics. So long as the core does not go into saturation, the valves will clip naturally as they drop the available voltage across them. In single ended systems the output harmonics will be largely even ordered due to the valve's relatively non linear characteristics at large signal swings. This

4815-487: Is only true however if the magnetic core does NOT saturate. Early valve amplifiers used unregulated power supplies. This was due to the high cost associated with high-quality high-voltage power supplies. The typical anode (plate) supply was simply a rectifier , an inductor and a capacitor . When the valve amplifier was operated at high volume , the power supply voltage would dip, reducing power output and causing signal attenuation and compression. This dipping effect

4922-408: Is playing in another room, the low notes are easily heard, while the high notes are attenuated. An optical filter with the same function can correctly be called a low-pass filter, but conventionally is called a longpass filter (low frequency is long wavelength), to avoid confusion. In an electronic low-pass RC filter for voltage signals, high frequencies in the input signal are attenuated, but

5029-404: Is pushing the tubes beyond their normal rated maximum. Valve amplifiers—particularly those using class-A triodes —tend to produce asymmetric soft clipping that creates both even and odd harmonics. The increase in even harmonics is considered to create "warm"-sounding overdrive effects. A basic triode valve (tube) contains a cathode , a plate and a grid. When a positive voltage is applied to

5136-425: Is said that this "preserves the original dynamics of the input signal which otherwise would get lost at the threshold of clipping" and "avoids muddiness and vastly improves clarity and responsiveness." Characteristic of the distortion is the symmetrical nature, which produces mainly odd-order harmonics for a sine wave input. All this justifies the "vacuum tube" sound, and the "screaming" tone. As well, Tamura added

5243-592: Is the complement of a high-pass filter . In optics, high-pass and low-pass may have different meanings, depending on whether referring to the frequency or wavelength of light, since these variables are inversely related. High-pass frequency filters would act as low-pass wavelength filters, and vice versa. For this reason, it is a good practice to refer to wavelength filters as short-pass and long-pass to avoid confusion, which would correspond to high-pass and low-pass frequencies. Low-pass filters exist in many different forms, including electronic circuits such as

5350-615: Is the cutoff frequency of the filter. The most common way to characterize the frequency response of a circuit is to find its Laplace transform transfer function, H ( s ) = V o u t ( s ) V i n ( s ) {\displaystyle H(s)={V_{\rm {out}}(s) \over V_{\rm {in}}(s)}} . Taking the Laplace transform of our differential equation and solving for H ( s ) {\displaystyle H(s)} we get A discrete difference equation

5457-505: Is used as an anti-aliasing filter before sampling and for reconstruction in digital-to-analog conversion . An ideal low-pass filter completely eliminates all frequencies above the cutoff frequency while passing those below unchanged; its frequency response is a rectangular function and is a brick-wall filter . The transition region present in practical filters does not exist in an ideal filter. An ideal low-pass filter can be realized mathematically (theoretically) by multiplying

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5564-540: The Hammond organ as used in blues and the Fender Rhodes as used in rock music; with these instruments and genres, keyboardists often purposely overdrive a tube amplifier to get a natural overdrive sound. Another example of instrument amplification where as little distortion as possible is sought is with acoustic instrument amplifiers, designed for musicians playing instruments such as the mandolin or fiddle in

5671-628: The Maestro FZ-1 Fuzz-Tone in 1962, one of the first commercially-successful mass-produced guitar pedals. Shortly thereafter, the American instrumental rock band The Ventures asked their friend, session musician and electronics enthusiast Orville "Red" Rhodes for help recreating the Grady Martin "fuzz" sound. Rhodes offered The Ventures a fuzzbox he had made, which they used to record "2000 Pound Bee" in 1962. In 1964,

5778-463: The RC time constant equals the sampling period. If α ≪ 0.5 {\displaystyle \alpha \;\ll \;0.5} , then RC is significantly larger than the sampling interval, and Δ T ≈ α R C {\displaystyle \Delta _{T}\;\approx \;\alpha RC} . The filter recurrence relation provides a way to determine

5885-537: The audio console ; use attenuation "pads" (a button on audio console channel strips, DI unit and some bass amplifiers ); and use electronic audio compressor effects and limiters to prevent sudden volume peaks from vocal mics from causing unwanted distortion. Though some bass guitar players in metal and punk bands intentionally use fuzz bass to distort their bass sound, in other genres of music, such as pop, big band jazz and traditional country music , bass players typically seek an undistorted bass sound. To obtain

5992-440: The heavy metal sound through a combined use of high volumes and heavy distortion. The word distortion refers to any modification of wave form of a signal , but in music it is used to refer to nonlinear distortion (excluding filters) and particularly to the introduction of new frequencies by memoryless nonlinearities. In music the different forms of linear distortion have specific names describing them. The simplest of these

6099-515: The smoothing factor is within the range 0 ≤ α ≤ 1 {\displaystyle 0\;\leq \;\alpha \;\leq \;1} . The expression for α yields the equivalent time constant RC in terms of the sampling period Δ T {\displaystyle \Delta _{T}} and smoothing factor α , Recalling that note α and f c {\displaystyle f_{c}} are related by, and If α =0.5, then

6206-522: The "high gain, scooped mids" sounds associated with heavy metal; fuzz boxes are designed to emulate the distinctive sound of the earliest overdrive pedals such as the Big Muff and the Fuzz Face . Most overdrive/distortion pedals can be used in two ways: a pedal can be used as a "boost" with an already overdriven amplifier to drive it further into saturation and "color" the tone, or it can be used with

6313-548: The Fourier transform is taken, filtered in the frequency domain, followed by an inverse Fourier transform. Only O(n log(n)) operations are required compared to O(n ) for the time domain filtering algorithm. This can also sometimes be done in real time, where the signal is delayed long enough to perform the Fourier transformation on shorter, overlapping blocks. There are many different types of filter circuits, with different responses to changing frequency. The frequency response of

6420-641: The Ibanez brand in the 1970s–1980s, produce their own version of the Tube Screamer (called Overdrives: the OD-808 and OD-9 as opposed to Tube Screamer, TS). According to Susumu Tamura ( 田村進 ) of Maxon, the designer of the Tube Screamer, the initial design concept was to create something to compete with the BOSS OD-1 and MXR Distortion+ . In doing so, he used an innovative circuit, using the monolithic operational amplifier device, introduced in early 70s, to create

6527-461: The Marshall JCM 900) utilize hybrid designs that employ both valve and solid-state components. Guitar distortion can be produced by many components of the guitar's signal path, including effects pedals, the pre-amplifier, power amplifier, and speakers. Many players use a combination of these to obtain their "signature" tone. The pre-amplifier section of a guitar amplifier serves to amplify

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6634-964: The Park " (1950). In the early 1950s, guitar distortion sounds started to evolve based on sounds created earlier in the decade by accidental damage to amps, such as in the popular early recording of the 1951 Ike Turner and the Kings of Rhythm song " Rocket 88 ", where guitarist Willie Kizart used a vacuum tube amplifier that had a speaker cone slightly damaged in transport. Electric guitarists began "doctoring" amplifiers and speakers to emulate this form of distortion. Electric blues guitarist Willie Johnson of Howlin' Wolf ′s band began deliberately increasing gain beyond its intended levels to produce "warm" distorted sounds. Guitar Slim also experimented with distorted overtones, which can be heard in his hit electric blues song " The Things That I Used to Do " (1953). Chuck Berry 's 1955 classic " Maybellene " features

6741-475: The TS10 alongside the 4558, is strangely regarded as the "ugly duckling of TS opamps". In reality, the type of op-amp has little to do with the sound of the pedal, which is dominated by the diodes in the op-amp's feedback path. (See Op-amp swapping .) The pedal was popularized by Stevie Ray Vaughan and Lee Ritenour . Phish guitarist Trey Anastasio implements two TS9 Tube Screamers in his rig. Gary Moore used

6848-466: The TS9 predominantly for 30 years which was key to his signature lead guitar sound. Adrian Smith of Iron Maiden has used a TS9 in a majority of his studio and live rigs over the years. It is widely used in genres as diverse as country, blues and metal. The Tube Screamer has since spawned many clones and modified versions. Possible modifications include use of mismatched, or different diodes (for example,

6955-404: The amplified signal are proportional to the input signal—so long as the voltage of the input signal does not exceed the valve's "linear region of operation". The linear region falls between Multiple stages of valve gain/clipping can be "cascaded" to produce a thicker and more complex distortion sound. In layperson's terms, a musician will plug a fuzz pedal into a tube amp that is being "cranked" to

7062-415: The centre midrange (750 Hz) results in what is popularly known as a "scooped" sound (since the midrange frequencies are "scooped" out). Conversely, decreasing the bass while increasing the midrange and treble creates a punchy, harsher sound. Rolling off all of the treble produces a dark, heavy sound. While musicians intentionally create or add distortion to electric instrument signals or vocals to create

7169-409: The circuit at voltages that are too low for the circuit components, resulting in greater non-linearity and distortion. These designs are referred to as "starved plate" configurations, and result in an "amp death" sound. Solid-state amplifiers incorporating transistors and/or op amps can be made to produce hard clipping. When symmetrical, this adds additional high-amplitude odd harmonics, creating

7276-584: The difference equation Comparing the reconstructed output signal from the difference equation, V n = β V n − 1 + ( 1 − β ) v n {\displaystyle V_{n}=\beta V_{n-1}+(1-\beta )v_{n}} , to the step input response, v out ( t ) = V i ( 1 − e − ω 0 t ) {\displaystyle v_{\text{out}}(t)=V_{i}(1-e^{-\omega _{0}t})} , we find that there

7383-466: The early 741, and used in thousands of consumer and industrial designs. In fact, JRC4558D is nothing else than the licensed product manufactured by Japan Radio Company ( 日本無線株式会社 ) , and identical to any other 4558 chip. Other popular chips used included the TL072 (a JFET input type, highly popular in 80s), "original" TI RC4558P, and OPA2134. The TA75558 (yet another version, made by Toshiba ), standard in

7490-557: The electronic circuitry of his amplifiers so as to achieve a "brighter, louder" sound and fuller distortion capabilities. Also in 1966, Syd Barrett of Pink Floyd created the song Interstellar Overdrive , a song made entirely in electric distortion. It was released a year later in modified form on their debut album The Piper at the Gates of Dawn . In the late 1960s and early 1970s hard rock bands such as Deep Purple , Led Zeppelin and Black Sabbath forged what would eventually become

7597-684: The end of 1965. Other early fuzzboxes include the Mosrite FuzzRITE and Arbiter Group Fuzz Face used by Jimi Hendrix , the Electro-Harmonix Big Muff Pi used by Hendrix and Carlos Santana , and the Vox Tone Bender used by Paul McCartney to play fuzz bass on " Think for Yourself " and other Beatles recordings. In 1966, Jim Marshall of the British company Marshall Amplification began modifying

7704-592: The filter has little attenuation below the cutoff frequency determined by its RC time constant . For current signals, a similar circuit, using a resistor and capacitor in parallel , works in a similar manner. (See current divider discussed in more detail below .) Electronic low-pass filters are used on inputs to subwoofers and other types of loudspeakers , to block high pitches that they cannot efficiently reproduce. Radio transmitters use low-pass filters to block harmonic emissions that might interfere with other communications. The tone knob on many electric guitars

7811-407: The finite impulse response filter has an unbounded number of coefficients operating on an unbounded signal. In practice, the time-domain response must be time truncated and is often of a simplified shape; in the simplest case, a running average can be used, giving a square time response. For non-realtime filtering, to achieve a low pass filter, the entire signal is usually taken as a looped signal,

7918-561: The horizontal line at this peak. The meanings of 'low' and 'high'—that is, the cutoff frequency —depend on the characteristics of the filter. The term "low-pass filter" merely refers to the shape of the filter's response; a high-pass filter could be built that cuts off at a lower frequency than any low-pass filter—it is their responses that set them apart. Electronic circuits can be devised for any desired frequency range, right up through microwave frequencies (above 1 GHz) and higher. Continuous-time filters can also be described in terms of

8025-432: The horizontal line to the right and the diagonal line to the upper-left (the asymptotes of the function), they intersect at exactly the cutoff frequency , 3 dB below the horizontal line. The various types of filters ( Butterworth filter , Chebyshev filter , Bessel filter , etc.) all have different-looking knee curves . Many second-order filters have "peaking" or resonance that puts their frequency response above

8132-466: The infinite future and past, to perform the convolution. It is effectively realizable for pre-recorded digital signals by assuming extensions of zero into the past and future, or, more typically, by making the signal repetitive and using Fourier analysis. Real filters for real-time applications approximate the ideal filter by truncating and windowing the infinite impulse response to make a finite impulse response ; applying that filter requires delaying

8239-552: The input and output are taken at evenly spaced points in time separated by Δ T {\displaystyle \Delta _{T}} time. Let the samples of v in {\displaystyle v_{\text{in}}} be represented by the sequence ( x 1 , x 2 , … , x n ) {\displaystyle (x_{1},\,x_{2},\,\ldots ,\,x_{n})} , and let v out {\displaystyle v_{\text{out}}} be represented by

8346-453: The input frequencies are not already harmonically related. For instance, playing a power chord through distortion results in intermodulation that produces new subharmonics . "Soft clipping" gradually flattens the peaks of a signal which creates a number of higher harmonics which share a harmonic relationship with the original tone. "Hard clipping" flattens peaks abruptly, resulting in higher power in higher harmonics. As clipping increases,

8453-415: The keys; however, the performer can still control the volume with drawbars and the expression pedal). Heavy metal music has evolved around these restrictions, using complex rhythms and timing for expression and excitement. Lighter distortions and overdrives can be used with triadic chords and seventh chords; as well, lighter overdrive allows more control of dynamics. Power valves (tubes) can be overdriven in

8560-412: The most extreme fuzz pedals, players may choose to play mostly single notes, because the fuzz can make even single notes sound very thick and heavy. Heavy distortion also tends to limit the player's control of dynamics (loudness and softness)—similar to the limitations imposed on a Hammond organ player (Hammond organ does not produce louder or softer sounds depending on how hard or soft the performer plays

8667-501: The next input. This exponential smoothing property matches the exponential decay seen in the continuous-time system. As expected, as the time constant RC increases, the discrete-time smoothing parameter α {\displaystyle \alpha } decreases, and the output samples ( y 1 , y 2 , … , y n ) {\displaystyle (y_{1},\,y_{2},\,\ldots ,\,y_{n})} respond more slowly to

8774-423: The notation V n = v o u t ( n T ) {\displaystyle V_{n}=v_{\rm {out}}(nT)} and v n = v i n ( n T ) {\displaystyle v_{n}=v_{\rm {in}}(nT)} , and substituting our sampled value, v n = V i {\displaystyle v_{n}=V_{i}} , we get

8881-422: The ordinary input signal amplitude, thus overdriving the amplifier) Note : product names may not accurately reflect type of circuit involved - see above. A fuzz box alters an audio signal until it is nearly a square wave and adds complex overtones by way of a frequency multiplier . Vacuum tube or "valve" distortion is achieved by "overdriving" the valves in an amplifier. In layman's terms, overdriving

8988-405: The output samples in terms of the input samples and the preceding output. The following pseudocode algorithm simulates the effect of a low-pass filter on a series of digital samples: The loop that calculates each of the n outputs can be refactored into the equivalent: That is, the change from one filter output to the next is proportional to the difference between the previous output and

9095-446: The output to + and - one diode volt-drop, although due to the exponential I-V curve of the diodes this is not a hard limit. A "drive" potentiomenter in the feedback path provides variable gain. The original 4558 based circuit uses transistor buffers at both the input and the output, to improve impedance matching. This is mathematically equivalent to mixing the input signal with a clipped version of itself, however. Thought of this way, it

9202-507: The output, and a modern electronic field-effect transistor (FET) "noiseless" bypass switching to turn the effect on and off. The TS7 allows switching between a "TS9" mode, in which the circuit and all relevant component values are identical to the vintage model, and a "Hot" mode, which introduces an additional gain stage. Yet another variant is the Ibanez ST9 Super Tube that features a fourth knob ("Mid Boost"), which provides

9309-420: The overall audio mix of the band. This, along with its versatility as a simple distortion, has made the pedal very popular for a wide variety of styles and situations. The pedal was produced with many variants: The Tube Screamer pedal was preceded by the orange "Overdrive" (OD) and green "Overdrive-II" (OD-II). These came in narrower boxes without battery covers. There was also a reddish "Overdrive-II" which had

9416-698: The peak of the signal. As this effect is more pronounced with higher input signals, the harder "attack" of a note will be compressed more heavily than the lower-voltage "decay", making the latter seem louder and thereby improving sustain . Additionally, because the level of compression is affected by input volume, the player can control it via their playing intensity: playing harder results in more compression or "sag". In contrast, modern amplifiers often use high-quality, well-regulated power supplies. Guitar loudspeakers are designed differently from high fidelity stereo speakers or public address system speakers. While hi-fi and public address speakers are designed to reproduce

9523-437: The plate, a current of negatively charged electrons flows to it from the heated cathode through the grid. This increases the voltage of the audio signal , amplifying its volume. The grid regulates the extent to which plate voltage is increased. A small negative voltage applied to the grid causes a large decrease in plate voltage. Valve amplification is more or less linear—meaning the parameters (amplitude, frequency, phase) of

9630-416: The power amp. When the preamp volume is set high to generate high distortion levels, the master volume lowered, keeping the output volume at manageable levels. Demo of a Big Muff Analog overdrive/distortion pedals work on similar principles to preamplifier distortion. Because most effects pedals are designed to operate from battery voltages, using vacuum tubes to generate distortion and overdrive

9737-404: The power section hard. Many valve-based amplifiers in common use have a push-pull output configuration in their power section, with matched pairs of tubes driving the output transformer . Power amplifier distortion is normally entirely symmetric, generating predominantly odd-order harmonics. Because driving the power valves this hard also means maximum volume, which can be difficult to manage in

9844-516: The recent powerful and "fat" Gibson humbucker pickups, and controlled "feedback" ( Larsen effect ). The resultant sound can be heard on his highly influential 1958 instrumental , " Rumble " and Rawhide. In 1961, Grady Martin scored a hit with a fuzzy tone caused by a faulty preamplifier that distorted his guitar playing on the Marty Robbins song " Don't Worry ". Later that year Martin recorded an instrumental tune under his own name, using

9951-497: The reconstructed output signal. The error produced from time variant inputs is difficult to quantify but decreases as T → 0 {\displaystyle T\rightarrow 0} . Many digital filters are designed to give low-pass characteristics. Both infinite impulse response and finite impulse response low pass filters, as well as filters using Fourier transforms , are widely used. The effect of an infinite impulse response low-pass filter can be simulated on

10058-487: The same faulty preamp. The song, on the Decca label, was called "The Fuzz." Martin is generally credited as the discoverer of the "fuzz effect." The recording engineer from Martin's sessions, Glenn Snoddy , partnered with fellow WSM radio engineer Revis V. Hobbs to design and build a stand-alone device that would intentionally create the fuzzy effect. The two engineers sold their circuit to Gibson , who introduced it as

10165-439: The same way that pre-amplifier valves can, but because these valves are designed to output more power, the distortion and character they add to the guitar's tone is unique. During the 1960s to early 1970s, distortion was primarily created by overdriving the power valves. Because they have become accustomed to this sound , many guitar players favour this type of distortion, and thus set their amps to maximum levels in order to drive

10272-455: The sequence ( y 1 , y 2 , … , y n ) {\displaystyle (y_{1},\,y_{2},\,\ldots ,\,y_{n})} , which correspond to the same points in time. Making these substitutions, Rearranging terms gives the recurrence relation That is, this discrete-time implementation of a simple RC low-pass filter is the exponentially weighted moving average By definition,

10379-408: The sessions, arguing that "that guitar sounds like a nice horn section". In the late 1950s, Guitarist Link Wray began manipulating his amplifiers' vacuum tubes to create a "noisy" and "dirty" sound for his solos after a similarly accidental discovery. Wray also poked holes in his speaker cones with pencils to further distort his tone, used electronic echo chambers (then usually employed by singers),

10486-551: The signal for a moderate period of time, allowing the computation to "see" a little bit into the future. This delay is manifested as phase shift . Greater accuracy in approximation requires a longer delay. Truncating an ideal low-pass filter result in ringing artifacts via the Gibbs phenomenon , which can be reduced or worsened by the choice of windowing function. Design and choice of real filters involves understanding and minimizing these artifacts. For example, simple truncation of

10593-413: The signal processing chain, including multiple stages of preamp distortion, power valve distortion, output and power transformer distortion, and guitar speaker distortion. Much of the distortion character or voicing is controlled by the frequency response before and after each distortion stage. This dependency of distortion voicing on frequency response can be heard in the effect that a wah pedal has on

10700-509: The signal. Some speakers are designed to have much clean headroom , while others are designed to break up early to deliver grit and growl. Guitar amp modeling devices and software can reproduce various guitar-specific distortion qualities that are associated with a range of popular "stomp box" pedals and amplifiers. Amp modeling devices typically use digital signal processing to recreate the sound of plugging into analogue pedals and overdriven valve amplifiers. The most sophisticated devices allow

10807-400: The sinc function will create severe ringing artifacts, which can be reduced using window functions that drop off more smoothly at the edges. The Whittaker–Shannon interpolation formula describes how to use a perfect low-pass filter to reconstruct a continuous signal from a sampled digital signal . Real digital-to-analog converters uses real filter approximations. The time response of

10914-416: The sound with as little distortion as possible, guitar speakers are usually designed so that they will shape or color the tone of the guitar, either by enhancing some frequencies or attenuating unwanted frequencies. When the power delivered to a guitar speaker approaches its maximum rated power, the speaker's performance degrades, causing the speaker to "break up", adding further distortion and colouration to

11021-422: The subsequent distortion stage, or by using tone controls built into the guitar, the preamp or an EQ pedal to favor the bass or treble components of the guitar pickup signal prior to the first distortion stage. Some guitarists place an equalizer pedal after the distortion effect, to emphasize or de-emphasize different frequencies in the distorted signal. Increasing the bass and treble while reducing or eliminating

11128-417: The user to customize the simulated results of using different preamp, power-tube, speaker distortion, speaker cabinet, and microphone placement combinations. For example, a guitarist using a small amp modeling pedal could simulate the sound of plugging their electric guitar into a heavy vintage valve amplifier and a stack of 8 X 10" speaker cabinets. Guitar distortion is obtained and shaped at various points in

11235-698: The way to the right until the speaker was screaming." In 1956, guitarist Paul Burlison of the Johnny Burnette Trio deliberately dislodged a vacuum tube in his amplifier to record " The Train Kept A-Rollin " after a reviewer raved about the sound Burlison's damaged amplifier produced during a live performance. According to other sources Burlison's amp had a partially broken loudspeaker cone. Pop-oriented producers were horrified by that eerie "two-tone" sound, quite clean on trebles but strongly distorted on basses, but Burnette insisted on releasing

11342-537: Was invented. Lower-power valve amps (such as a quarter-watt or less) , speaker isolation cabinets , and low-efficiency guitar speakers are also used to tame the volume. Power-valve distortion can also be produced in a dedicated rackmount valve power amp. A modular rackmount setup often involves a rackmount preamp, a rackmount valve power amp, and a rackmount dummy load to attenuate the output to desired volume levels. Some effects pedals internally produce power-valve distortion, including an optional dummy load for use as

11449-452: Was sold only in Europe and Australia. The TS9 and TS808 pedals have been reissued, and according to the company, feature the same circuitry, electronics and design components that helped shape the famous Tube Screamer sound. Some musicians have a technician perform modifications to the unit to change the sound to their liking. Also, Maxon , which produced the original Tube Screamer pedals for

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