Guitar Pedals: Boost Vs. Overdrive Vs. Distortion Vs. Fuzz
Written by Arthur in Effects Pedals
There are hundreds, if not thousands, of different guitar effect pedals on that market. Boost, overdrive, distortion and fuzz are some of the most common for getting that aggressive sound for your 6 string (or 7… or 8… or 9 and so forth). Knowing the differences between these pedal types will help tremendously in narrowing your search.
What is the difference between boost, fuzz, overdrive and distortion pedals?
Boost pedals increase the signal level without adding any distortion (ideally).
Overdrive pedals aim to add soft clipping (saturation) to the signal while mildly shaping the tone of the input signal.
Distortion pedals aim to add significant distortion, saturation and compression to the signal to degrade the tone of the input signal regardless of how loud the input signal is.
Fuzz pedals add even more compression and square-like hard clipping, causing severe distortion reminiscent of broken tube equipment.
In this article, we'll define each of these pedal types with greater detail and discuss the subtleties of each, along with examples of each to help further our understanding.
A Primer On Audio Signal Gain And Distortion
What Is A Boost Pedal?
What Is An Overdrive Pedal?
What Is A Distortion Pedal?
What Is A Fuzz Pedal?
Before we get into the nitty-gritty (and the grittiness) of boost, OD, distortion and fuzz pedals, let's go over the definition of gain and distortion when it comes to guitar signals.
To skip ahead to the definitions of the 4 pedal types, click here!
Guitar Audio Signals
First, it's important to know that the signal coming out of your electric guitar is an analog audio signal.
Note that the frequency response of human hearing is universally accepted as 20 Hz to 20,000 Hz (20 kHz). Guitar pickups typically only pick up frequencies as high as 6-8 kHz, and guitar amplifiers usually only output as high as 5-6 kHz.
Guitar strings vibrate at fundamental frequencies and have odd and even harmonics (multiples of the fundamental) that sound along with each note played on the guitar.
These fundamental frequencies and harmonics are produced in sound waves. They are also picked up by the guitar's pickups to be turned into audio signals (electrical variations in voltage).
The fundamental frequencies of the guitar in standard tuning (A4 = 440 Hz) are:
e: 330 Hz
B: 247 Hz
G: 196 Hz
D: 147 Hz
A: 110 Hz
E: 82 Hz
*Note that each fundamental frequency listed above is rounded to the nearest whole number.
Playing the A string as an example, we would produce and hear the fundamental frequency (110 Hz) along with upper odd and even harmonics at varying amplitudes and decay rates (220, 330, 440, 550, 660, 770, 880 Hz and so on).
These harmonics give the guitar its timbre or sonic character. As we'll find out, the distortion-type pedals discussed in the article affect these harmonics and, therefore, the timbre of the guitar!
Related article: Fundamental Frequencies Of Musical Notes In A=432 & A=440 Hz
So what we end up with is a guitar audio signal (between about 82 Hz up to 8,000 Hz) with different notes and the harmonics that come with the notes. This signal is converted from the vibrating strings by the guitar's pickup and is sent to the guitar pedals (and beyond) via 1/4″ TS "patch" cables.
Now that we understand the basics, we can move on to signal gain.
Audio Signal Gain
In terms of audio and electrical signals, gain is the ratio of the output signal amplitude to the input signal amplitude of an amplifying device.
In other words, gain tells us how much an amplifier will boost the signal amplitude. The amplitude of an analog audio signal (like the signal from an electric guitar's pickup) is measured in AC volts (or millivolts).
Gain is a ratio and is often given in decibels. The gain controls on guitar pedals are generally labelled as "level" or "volume."
Related article: What Are Decibels? The Ultimate dB Guide For Audio & Sound
Gain, naturally, will effectively increase the loudness of your signal. That is, however, until the upper limit of the amplifier circuitry is reached, in which case distortion begins to ensue.
Audio Signal Distortion
Audio distortion is largely defined by the differences in the waveform between an input signal and an output signal (disregarding changes in amplitude).
So far, we've discussed gain and increasing the amplitude of the output signal relative to the input signal. However, distortion will happen when an audio signal is amplified past the amplifier's limits (in our case, the amp in the guitar effects pedal).
The first type of distortion worth noting is soft clipping distortion or saturation. This happens when an input signal (shown below in blue) is amplified past a "maximum point" (Vcc), and significant compression happens beyond Vcc.
The amplified signal (shown below in red) is distorted near its peaks past +Vcc and –Vcc.
Soft Clipping Distortion
Soft clipping or saturation happens in many analog circuits based on tape and vacuum tubes. The compression of the signal extends beyond the "max point" and causes warm/musical saturation distortion in the signal. This saturation is apparent in the increased amplitude of the signal's upper harmonics.
Boost pedals, when overdriven, can yield this soft clip saturation. Overdrive pedals are designed to produce this effect, adding a bit of musical "bite" to the input signal in the form of soft distortion.
With soft clipping, the amount of distortion is largely dependent on the input level of the signal.
Operational amplifiers are generally used in soft clipping guitar pedals.
Hard clipping happens when the maximum output of an amplifier is the absolute max and cannot be exceeded.
Hard clipping will cause the entire top (and/or bottom) of the waveform to be cut off, as shown in the illustration below:
Hard Clipping Distortion
Hard clipping happens in digital audio, where the absolute maximum output is 0 dBFS. It also happens with hard limiters (as opposed to compressors).
The sound of a hard clipped signal is much grittier and "more distorted" than the sound of a soft clipped signal. This effect can be achieved with transistors or digital circuits in guitar pedals.
With hard clipping ceilings set low, the amount of distortion in the output signal is much less dependent on the input signal level. This is unlike the soft clipping (with a high ceiling) mentioned earlier.
Distortion and fuzz pedals will use hard clipping (or simulation of hard clipping) to really distort the signal.
If we were to really drive (amplify) a signal into hard clipping, we would end up with, essentially, a square wave:
Hard Square Wave Distortion
Fuzz pedals typically supply this uber-compressed type of distortion where the output signal is way over-distorted. These pedals are more difficult to control tone-wise but sound super distorted, which is optimal in some situations.
With hardcore fuzz pedals, the input signal dynamics have little effect on the amount of distortion. The pedal is designed to distort any and all signal coming through!
Now that we understand the basics of guitar audio, gain and distortion, let's get into each of the gain-based and distortion pedal types.
A boost pedal is essentially an instrument preamplifier for your guitar in the form of a stompbox.
The goal of the boost pedal is to apply gain to the guitar signal, amplifying it without causing any distortion to the signal.
Boost pedals are great for increasing the guitar signal's level without affecting the signal's tone. In a perfect world, that is exactly what a boost pedal would do.
However, boost pedals (like other preamps) will likely have a slight amount of colouration. The bigger issue is that the rest of the signal chain after the boost pedal will likely react differently to the amplified signal than the original signal.
That all being said, if a clean boost in gain is what you're after, a boost pedal is for you (hence the name)!
Of course, as we've discussed prior, there is a chance that a boost pedal will output an overdriven/saturated signal. Try running a guitar with a hot (high level) pickup through a boost pedal with its gain and/or level knobs maxed out, and you'll likely have some amount of soft clipping.
Boost Pedal Examples
It's always great to look at examples to put things in context. Examples of boost pedals include:
TC Electronic Spark Booster
Walrus Audio Emissary
Before we get into our examples, feel free to check out My New Microphone's full directory on guitar effects pedal manufacturers.
TC Electronic Spark Booster Boost Pedal
The TC Electronic Spark (link to check the price on Amazon) is an example of a boost pedal with 26 dB of completely clean gain (controlled via the "Level" control).
The TC Electronic Spark Booster is featured in My New Microphone's Top 9 Best Boost/Preamp Pedals For Guitar & Bass.
The TC Spark also has a gain knob to add grit and saturation to the signal, similar to how overdrive works. In addition to the overdrive functionality, the SPark also packs a filter to increase (or decrease) the bass and treble ranges of the signal.
TC Electronic also has the Spark Mini (link to check the price on Amazon) as a simpler, more affordable option with 20 dB of clean gain.
The controls of the TC Electronic Spark Booster are:
Gain potentiometer
Level potentiometer
Bass potentiometer
Treble potentiometer
Fat/Clean/Mid switch
On/Off stomp switch
TC Electronic is featured in My New Microphone's Top 11 Best Guitar/Bass Effects Pedal Brands To Know & Use.
Walrus Audio Emissary Boost Pedal
The Walrus Audio Emissary (link to check the price on Amazon) is a parallel boost pedal meaning it has two different boost circuits in its design.
The "Bright" boost is a JFET (junction gate field-effect transistor) that boosts the level with a little extra boost to the upper frequencies.
The "Mid" boost is an op-amp circuit. This circuit will increase the midrange frequencies of the signal. There is a toggle switch to choose 800 Hz or 1 kHz as the centre point for the mid boost.
The controls of the Walrus Audio Emissary are:
Bright potentiometer
Mid potentiometer
800 Hz – 1 kHz switch for Mid-frequency adjustment
Walrus Audio is featured in My New Microphone's Top 11 Best Boutique Guitar/Bass Pedal Brands To Know & Use.
An overdrive pedal is designed to recreate or, at the very least, simulated the effect of overdriving an amplifier.
As discussed earlier, pushing a tube (or, sometimes, an op-amp) past its linear max will cause soft distortion in the output signal. This is known as overdrive and is the essence of what overdrive pedals aim to achieve, only in a stompbox rather than in a guitar amplifier.
In a way, an overdrive pedal can be thought of as a boost pedal with a lower ceiling that allows for soft clipping!
Most overdrive pedals on the market use are solid-state clipping diodes or cascading gain through multiple transistor stages. Actual vacuum tubes may not fare so well in a device designed to be stomped on!
However, there are certainly OD pedals on the market that use actual vacuum tubes in their circuits. These pedals are designed to be overdriven in the traditional sense.
Regardless of the circuit design, all OD pedals are made to give guitarists the extra warmth and boost of an overdriven signal!
An overdriven guitar signal maintains much of its definition but acquires a varying amount of warmth and saturation.
Overdrive Pedal Examples
Overdrive pedals are common on the market today. Let's have a look at two solid-state OD pedals and another example of an OD pedal with actual tubes in its circuit design.
Fulltone OCD V2
Ibanez TS9 Tube Screamer
Hughes & Kettner Tube Factor
Fulltone OCD V2 Overdrive Pedal
The Fulltone OCD V2 (link to check the price on Amazon) is a less-compressed version of the original OCD V2.
The Fulltone OCD V2 is featured in My New Microphone's Top 10 Best Overdrive Pedals For Guitar & Bass.
Fulltone was the first pedal manufacturer to use MOSFETs as clipping devices, and the OCD was the first pedal to boast such a design. This pedal is also configured to clip against the reference voltage rather than to ground.
The benefit of such a design is not just bragging rights for doing it first but also the incredible touch sensitivity one would expect of a high-end overdrive circuit.
Hit the strings softly, and there is little effect. Hit the strings hards and hear tons of overdrive. This overdrive pedal fits the overdrive definition perfectly!
The controls of the Fulltone OCD V2 are:
Volume potentiometer
Drive potentiometer
Tone potentiometer
HP (high-pass filter) – LP (low-pass filter) switch
Ibanez TS9 Tube Screamer Overdrive Pedal
The Ibanez TS9 Tube Screamer (link to check the price on Amazon) is often copied but never duplicated. This famed green pedal is practically synonymous with the term "overdrive pedal".
The Ibanez TS9 is also featured in My New Microphone's Top 10 Best Overdrive Pedals For Guitar & Bass.
In fact, many overdrive pedals on the market are based heavily on the Tube Screamer with only the slightest variations in design. The TS9 is a reissue of this legendary pedal that is very much the same as the original.
As the name suggests, the TS9 aims to mimic the sound of vacuum tubes that are turned way up. The pedal itself does not contain any tubes. Rather, its solid-state circuit is designed to mimic the sound of an overdriven vacuum tube.
The controls of the Ibanez TS9 are:
Ibanez is featured in the following My New Microphone articles:
• Top 13 Best Bass Guitar Brands In The World
• Top 13 Best Electric Guitar Brands In The World
Hughes & Kettner Tube Factor Overdrive Pedal
The Hughes & Kettner Tube Factor (link to check the price on Amazon) is an overdrive pedal that utilizes an actual vacuum tube (a 12AX7 to be exact) in its overdrive circuit.
To be more precise, the Tube Factor is an overdrive and distortion pedal with two gain modes (Factor 1 and Factor 2).
Factor 1 is the soft-clipping overdrive circuit that utilizes the preamp tube. The circuit of Factor 2, however, is based on a solid-state diode which provides extra gain and harder clipping.
So, then, the Hughes & Kettner Tube Factor is not completely based on tube circuitry. It is only the preamp/overdrive circuit that utilizes the 12AX7.
The controls of the Hughes & Kettner Tube Factor are:
Output potentiometer
Voicing potentiometer
Factor 1 – Factor 2 stomp switch
Hughes & Kettner is featured in My New Microphone's Top 11 Best Guitar Amplifier Brands In The World.
Distortion pedals really distort/alter the sound of the input signal via hard clipping.
A distortion pedal will produce more aggressive, edgy and consistent distortion across the wide dynamic range of the input guitar signal. In other words, the harder distortion will be present in quiet notes and loud notes alike.
One or multiple clipping stages (often, but not always, transistor-based) are used to drive the signal into great amounts of distortion. The resulting sound is compressed and full of added harmonics, making it sound edgy and, well… distorted!
The hard clipping of the signal through a distortion pedal will introduce added harmonics and especially odd-order harmonic overtones.
These added harmonics, combined with the compression of the signal, create the distorted sound we know and love.
However, the distinction of chords (even simple triads) can become ill-defined with all these added harmonics. Too much harmonic content makes it difficult to make out the colour of individual notes in a chord.
Therefore, adding distortion to a guitar signal can make complex chords (anything other than a power chord, really) indistinguishable and noisy.
Distortion Pedal Examples
There are plenty of distortion pedals on the market today. Let's have a look at a few here.
Boss DS-1
MXR M75
The Boss DS-1 (link to check the price on Amazon) is a classic distortion pedal. Leave it up to Boss to produce classics of any pedal type!
The Boss DS-1 is featured in My New Microphone's Top 11 Best Distortion Pedals For Guitar & Bass.
The idea behind the DS-1 is to provide a hard-clipping distortion that maintains the nuances of dynamics. The circuit cranks up the signal into hard clipping, adding the saturation and compression demanded of distortion without completely decimating the input signal.
The result is a wonderfully tasty distortion that tracks the dynamics of the guitar signal with great precision.
The controls of the Boss DS-1 are:
Distortion potentiometer
Boss is featured in the following My New Microphone articles:
• Top 11 Best Guitar/Bass Effects Pedal Brands To Know & Use
• Top 11 Best Guitar Amplifier Brands In The World
• Top 11 Best Pedalboard Brands On The Market
MXR M75 Distortion Pedal
The MXR M75 (link to check the price on Amazon) is a highly responsive analog distortion pedal complete with a 3-band EQ to really fine-tune the sound.
The MXR M75 Super Badass Distortion is also featured in My New Microphone's Top 11 Best Distortion Pedals For Guitar & Bass.
The hard-clipping distortion of the M75 is incredibly versatile. Combine that with the EQ, and the Super Badass Distortion pedal is capable of achieving practically any distortion sound you'd ever want.
The controls of the MXR M75 are:
MXR is featured in My New Microphone's Top 11 Best Guitar/Bass Effects Pedal Brands To Know & Use.
Fuzz pedals take things a step further in terms of aggression and clipping. They are the most aggressive distortion-type pedals on the market.
So what's the difference between a distortion pedal and a fuzz pedal?
Remember our discussion on audio signal distortion?
Distortion pedals cause hard clipping in the signal that chops off the top (and/or bottom) of the signal waveform. As we've discussed, this causes significant distortion.
Pushing this hard clipping even further, we get a super-compressed square-like signal. Fuzz pedals perform this type of distortion that completely obliterates the input signal's waveform.
The fuzz pedal was actually born in the mid-1960s to emulate the sound of broken tubes in the signal chain.
Fuzz pedals are the most radical of the bunch mentioned here and are a great choice for getting a supremely distorted and compressed tone.
The compression of the signal within a fuzz pedal makes it so that pretty well any dynamic, from a softly played note to a heavily strummed power chord, get equally uncontrollable treatment and a disgustingly good crunch.
Fuzz pedals use transistors (rather than op-amps). In fact, they purposefully use lo-fi transistors to distort the signal down to a near-square waveform.
Square waves naturally have an infinite series of odd harmonics, which makes them sound particularly distorted (especially in comparison to the natural harmonic response of a clean guitar string). Of course, the bandwidth of a fuzz pedal-induced square-ish signal is limited by the guitar amp and other electronics down the signal path line.
The transistors used are typically silicon (for a brighter, sharper sound) or germanium (for a warmer, smoother sound).
Fuzz Pedal Examples
Let's now have a look at a few fuzz pedals on the market to further our understanding.
Electro-Harmonix Big Muff Nana Pi
Old Blood Noise Endeavors Haunt
Electro-Harmonix Nano Big Muff Pi Fuzz Pedal
The Electro-Harmonix Nano Big Muff Pi (link to check the price on Amazon) is nearly ubiquitous when it comes to fuzz pedal distortions, even though EHX themselves do not explicitly state the pedal is a fuzz.
The Nano Big Muff Pi has the same circuit and sound as the Big Muff Pi. The only difference is the size of the pedal.
This re-issue of sorts offers incredible sustain and compression and a rich fuzzy tone that guitarists and other musicians have come to known and love about the Big Muff line of pedals.
The pedal will severely alter the input signal to produce its fuzz output. This is exactly what makes the Big Muff line of pedals a go-to for so many guitarists.
The controls of the Electro-Harmonix Nano Big Muff Pi are:
Sustain potentiometer
Electro-Harmonix is featured in My New Microphone's Top 11 Best Guitar/Bass Effects Pedal Brands To Know & Use.
Old Blood Noise Endeavors Haunt Fuzz Pedal
The Old Blood Noise Endeavors Haunt (link to check the price on Amazon) is a gated fuzz pedal, meaning it will cut out the noise of the guitar signal under a certain level threshold.
The OBNE Haunt is featured in My New Microphone's Top 12 Best Fuzz Pedals For Guitar & Bass.
This helps reduce the hiss and noise between notes that could otherwise produce gross results. It also means we can get the filthy gated fuzz effect as we quickly dip above and below the threshold.
On top of the gate, the OBNE Haunt offers an incredible range of fuzz sounds. The Haunt fuzz pedal does it all, from sustained light fuzz to sawtooth-like output signals and everything in between.
The controls of the Old Blood Noise Endeavors Haunt are:
Fuzz potentiometer
Gate potentiometer
Mix potentiometer
Mode switch (toggle between two silicon transistors)
Low switch (boost low-end)
What order should effects pedals go in? Though there are no hard rules in music and art, the typical order of guitar effects pedals for optimal signal flow is as follows:
Dynamics pedals: compressors, filters, pitch shifters, volume pedals.
Gain-based pedals: boost, overdrive, distortion and fuzz pedals.
Modulation effects pedals: chorus, flanger, phaser and other modulation pedals.
Time-based effects pedals: delay and reverb pedals
*Volume pedals can go anywhere in the effects chain.
To learn more about order pedals for optimal signal flow, check out my article How To Order Guitar/Bass Pedals (Ultimate Signal Flow Guide).
What pedals should every guitarist have? Without getting into specific pedals, the most common and useful types of pedals for guitarists are as follow:
Tuner pedals
Boost, overdrive, distortion and/or fuzz pedals
Choosing the right effects pedals for your applications and budget can be a challenging task. For this reason, I've created My New Microphone's Comprehensive Effects Pedal Buyer's Guide. Check it out for help in determining your next pedal/stompbox purchase.