Fuzz bass (also called "bass overdrive" or "bass distortion") is a style of playing the electric bass which produces a buzzy, distorted, overdriven sound, which the name implies in an onomatopoetic fashion. Overdriving a bass signal significantly changes the timbre, adds overtones (harmonics), increases the sustain, and, if the gain is pushed high enough, creates a "breaking up" sound characterized by a growling, buzzy tone.
One of the earliest examples may be the 1961 Marty Robbins Country and Western song "Don't Worry." By the mid- to late-1960s, a number of bands began to list "fuzz bass" in addition to "electric bass" on their album credits. Two well-known examples are the Beatles' 1965 song "Think for Yourself" (from Rubber Soul) and the 1965 Rolling Stones song "Under My Thumb". Album or performance credits for fuzz bass can be found from every decade since then (see examples below).
Fuzz bass can be produced by overloading a bass amp's tube or transistor preamplifier, by using a bass fuzz or bass overdrive effect pedal, or for the most powerful effect, by combining both approaches. In the 1960s and early 1970s fuzz bass was associated with the psychedelic music (e.g., Edgar Broughton Band), progressive rock (e.g., Genesis), and psychedelic soul/funk (e.g., Sly and the Family Stone) styles, and it tended to be a "warmer", "smoother", and "softer" overdrive-type sound caused by soft, symmetrical clipping of the audio signal which "round[ed] off the signal peaks rather than razor-slicing" them and filtered out the harsher high harmonics.
In the 1980s and 1990s, overdriven bass tended to be associated with hardcore punk, death metal, grindcore (e.g., Napalm Death) and Industrial bands (e.g., Ministry), and the tone tended to be heavier, more metallic and more grinding. This is achieved by hard clipping of the bass signal, which leaves in "harsher high harmonics that can result in sounds that are heard as jagged and spikey." In the 1990s and 2000s, fuzz bass was also used by indie and alternative rock bands, with a notable example being Muse.
In the context of electric guitars, the terms "distortion", "overdrive" and "fuzz" are often used interchangeably, but they have subtle differences in meaning. Overdrive effects are the mildest of the three, producing "warm" natural overdrive overtones at quieter volumes and harsher distortion as gain is increased. A "distortion" effect produces approximately the same amount of distortion at any volume, and its sound alterations are much more pronounced and intense. A fuzzbox (or "fuzz box”) alters an audio signal until it is nearly a square wave and adds complex overtones by way of a frequency multiplier.
A fuzz bass sound can be created by turning up the volume of a tube amp or transistor amp to the point that "clipping" occurs, or by using an electric guitar fuzz, distortion or overdrive pedal. The downside of using a pedal designed for the electric guitar is that the lower end bass tone is mostly lost when the signal is heavily clipped.
Clipping is a form of waveform distortion that occurs when an amplifier is overdriven and attempts to deliver an output voltage or current beyond its maximum capability. Driving an amplifier into clipping may cause it to output power in excess of its published ratings. Clipping is a non-linear process that produces frequencies not originally present in the audio signal.
These frequencies can either be "harmonic", meaning they are whole number multiples of the signal's original frequencies, or "inharmonic", meaning dissonant odd-order overtones. Harmonic distortion produces harmonically related overtones while intermodulation distortion produces inharmonic overtones. "Soft clipping" gradually flattens the peaks of a signal and de-emphasizes higher odd harmonics. "Hard clipping" flattens peaks abruptly, resulting in harsh-sounding, high amplitude odd harmonics.
Since the late 1980s, manufacturers have been producing bass overdrive pedals specifically designed for the electric bass, and in many cases they found a way to keep the low fundamental pitch in along with the buzzy overdrive tone. One early model was the Ibanez "Bass Stack" bass overdrive pedal, which was sold in the late 1980s.
|Napalm Death live in Germany, 1987, the second song is half-way through the clip at 4 minutes, 37 seconds has a buzz-saw type heavy bass distortion, from YouTube, authorized by Earache Records.|
1980s grindcore groups, such as Napalm Death in the sound clip to the right, used a very heavy, distorted bass tone that resembles the sound of a grinding buzz saw.
The simplest fuzz bass pedals have knobs for controlling the volume level, the tone, and the fuzz or overdrive effect. More complex pedals have different distortion effects (e.g., overdrive and fuzz), gates to trigger the volume at which sounds will get overdriven, mixers to mix the natural and fuzzed sound in the player's desired proportions, and multiple band equalizers. Boutique fuzz bass pedals even have unusual effects such as a "starve" effect, which mimics the distortion sound a pedal gives with a dying battery, a diode selector (either silicon or germanium) for selecting the transistor overdrive tone, and an octave selector (above or below the pitch being played).
Standard overdrive effects for bass include:
- The AGRO bass overdrive is produced by Aguilar Amplification. The manufacturer claims that the pedal is "based on the saturation channel of Aguilar's celebrated AG 500 bass head" and that it can produce "everything from warm, tube-like overdrive to full on distortion" and all the "grind you need without sucking out your low end." It has a saturation (overdrive) knob, a contour knob, a presence knob, and an output knob.
- The Bass Brassmaster was introduced by Gibson in the early 1970s. A fuzz box variant, it used "induction circuitry to produce a brassy sound for bass guitar".
- The Bass BB Preamp distortion booster has bass and treble EQs. The manufacturer states that the "gain knob offers pristine clean boost to a hard overdriven distortion" and "compression for a smooth overall texture."A demonstration is provided at this YouTube link.
- The Bass Drive Plus pedal is made by Ashdown, an amplifier manufacturer. The maker claims that the product "generates a wide range of bass distortion effects from a slight grunge through to no holds barred, high-gain overdrive". It has knobs for "Drive", "Tone", and "Level", and it has a VU meter.
- The BASS OVERDRIVE BOD 100 is a low-priced pedal from Behringer. The maker claims that it produces "...rich, tube-like distortion, smooth sustain and super-fat tone" and that it is "designed specifically for bass, so the bottom-end won’t drop out" when the distortion is turned on.
- The BOSS ODB-3 Bass Overdrive is made by BOSS. The maker claims that it provides "chest-resonating distortion...[for] hard rock, thrash, and punk bassists." It has an overdrive control knob and a two-band equalizer. The pedal can be heard on this YouTube demonstration.
- The DigiTech XBD Bass Driver is maded by DigiTech. The maker claims that the pedal enables players to "go from a light overdrive to all out Stoner rock Fuzz or morph in between".
- The Electro-Harmonix Bass Blogger is a bass distortion pedal. The maker claims that it provides "finesse Bass distortion with a silky definition" and "mild distortion especially suited for bass guitar." A demonstration of the Bass Blogger's tone is available at this YouTube video.
- The Electro-Harmonix Big Muff Pi, while primarily designed for use with the electric guitar, is also used by bassists due to its good low end frequency response. It has knobs for "volume", "tone", and "sustain."
- The EBS Metal Drive Universal Distortion Pedal is a bass distortion pedal. The maker claims that it provides "high-gain distortion for use in modern metal music. The manufacturer claims that it has a "fat tone that keep the bottom solid."
- The El Grande Bass Fuzz is made by MXR Bass Innovations. The manufacturer claims that it is "a versatile and brutal fuzz designed just for bass" that takes a "classic 70’s fuzz circuit, re-tune[s] it for more low end,...[adds] a DEEP switch. There are also "Volume, Tone, and Fuzz controls".A demonstration of the El Grande is available on YouTube.
- The MXR Bass Fuzz is a fuzz pedal. The manufacturer describes it as a "[d]eluxe rare vintage fuzz" with "separate Dry and Wet level controls", thus enabling the bassist to preserve the low bass fundamental tone while the fuzzy overdrive sound is being produced. The buzzy, nasal tone of the MXR Bass Fuzz can be heard in this YouTube sample.
- The MXR Bass Blowtorch is a multipurpose pedal. The maker claims it can provide "anything from the traditional tube-like growl to scorching high gain distortion." The pedal "focusing the overdrive in the midrange frequencies." It has a three-band EQ and a blend knob for blending the clean signal with the overdrive signal. A demonstration of the Bass Blowtorch is available in this You Tube video.
- The GNI BSH Bass Shaper Pedal has an "Overdrive / Super Overdrive" setting to adjust the distortion. There are also "Drive" and "Level" knobs, and a "Super Overdrive" button.
- The Ibanez TS9B Bass Tube Screamer is a version of the classic Tube Screamer reconfigured for bass players. It has Level, Gain, Treble, Bass, and Wet/Dry Mix Controls.
- The Soundblox Pro Multiwave Bass Distortion is manufactured by Source Audio. The manufacturer claims that it offers "23 modern and distinctive distortion" options. It also has a "7-band equalizer, drive control, and separate mix knobs for clean and distorted signals." 
- The Soundblox Multiwave Bass Distortion is manufactured by Source Audio. It has less features than the Pro version, but it uses the same approach. It offers "21 varieties of [the company's] distortion algorithm," and the distortion can be allocated to specific frequencies.
- The Tech 21 Bass Boost Fuzz produces sounds ranging "from the fat, gritty sounds of the ‘60s fuzz bass, to the subterranean growl of industrial metal." As well, like the MXR Bass Fuzz and the BOSS Bass Overdrive, it enables the user to set how much "clean" bass tone is present along with the overdrive tone.
- The Tech21 Sansamp Bass Driver provides "Drive, Bass, Treble, Presence, Blend and Level" controls.
Boutique pedals are designed by smaller, independent companies and are typically produced in limited quantities. Some may even be hand-made, with hand-soldered connections. They are often more expensive than mass-produced pedals and offer non-standard features such as true-bypass switching, higher-quality components, innovative designs, and hand-painted artwork.
- The BASS BLOOM by FuzzHugger, is purported to provide "low-end and smooth clean blending", with gain, bloom (fuzz), starve (mimics a dying battery), clean volume and fuzz volume controls. The Premier Guitar review from October 2012 states that it "...offered endless textures of fuzz, while effectively preserving the low end". As well, it "...allows you to create a spectrum of different fuzz tones that work well with both active and passive basses. Bassists from rock to funk camps can find a number of useful sounds within its responsive controls, all at a price point that is competitive with its peers."
- The Bass TightDrive overdrive pedal is designed to "provide tighter low end." The pedal has a "Tight" knob, which allows the attack to vary from "smooth and singing to [a] chunky and aggressive attack." There are also Gain, Tone, and Volume controls, which enable the player to produce a variety of overdrive tones.
- The Battering Ram Overdrive and Fuzz, from Wounded Paw Effects, is designed for both electric guitar and electric bass. It has an overdrive switch, low and high frequency knobs, and a "fuzz" switch. There is also an "octave up" switch.
- The Black Cat Pedals Bass Octave Fuzz Pedal is inspired by the 1970s Bass Brassmaster pedal. The manufacturer claims that it adds a "unique fuzz tone that harkens back to that famous bass grind of the ’70s."
- The Brown Dog fuzz pedal "produce[s] rampaging waves of meat [i.e., fuzz] with your bass guitar while still keeping your basslines tight and letting the character of your instrument’s tone shine through." It has controls for "dirty", "clean", a gate control which determines at which point the fuzz will be created, and a "drive" control which ranges from "hard mode with maximum drive, ...[giving]...synth-like square wave tones" to soft mode, which "produces a classic warm bass fuzz."
- The Devi Ever FX Bass Fuzz is "bass heavy fuzz with [an] expansive filter tone control", which enables the player to "emphasize the highs, or lows" and an "intensity flip switch" which "increases fuzz intensity."
- The Depth Charge pedal by Prescription Electronics is "60s fuzz"-style effect. A Harmony Central review states that it add "a ton of fat tone, attack and (just the right amount) of fuzz."
- The Frantone Bassweet V1 is a "germanium transistorized bass" fuzz pedal. The manufacturer claims that it can produce "an impenetrable wall of low end" with a range of "sustain, compression, and tone" options.
- The FUZZPOTION pedal from Audio Monk is designed to provide fuzz for both electric guitar and electric bass. The manufacturer claims it provides "Fuzz/distortion so destructive you’ll rule the world!"
- The FZ002 bass fuzz is produced by Chunk Systems. The manufacturer claims that it has a "gating system to keep your basslines punchy and well defined whether you've got it set to make your sound a little crusty round the edges or transform it into rampaging waves of meat." It is handmade in Australia to order.
- The Hematoma, from HomeBrew Electronics is a "two channel bass guitar pedal consisting of a Pre-Amp and an Overdrive" which "can be used independently or combined. The manufacturer claims that there is "[n]o loss of low end." 
- The "Iron Ether Oxide" pedal is "a morphing gated fuzz, allowing the user to seamlessly morph between a raucous, industrial octave fuzz inspired by the Maestro Bass Brassmaster, to a modern synthy fuzz with a pinched, gated sound. It includes a clean blend to allow extreme amounts of fuzz without losing low end.". Each Iron Oxide pedal is hand-etched and painted.
- Laser Cannon HD from Daring Electronics is a bass distortion pedal. The manufacturer claims that it "[s]trikes the perfect balance of clean bass mixed with heavy distortion" and produces a range of sounds "from moderate to crunchy distortion or even thick fuzz", making it suitable for "rock, metal, industrial and hardcore" bands. It has a signal blend knob, an EQ knob, a range knob, a wave knob, a diode selector (either silicon or germanium), and octave selector (for adding an octave above or below), and a volume knob.
- The LODESTONE Bass Fuzz is made by Monolith Loudspeakers. The manufacturer claims that it is a "high gain transistor fuzz that will unleash the beast in your bass tone!"
- The Mad Professor Blueberry Bass Overdrive has a drive control and circuitry that "compresses and adds more signal distortion for a smooth, long sustaining tone." The Nature control "controls filtering but also determines what register distorts." 
- The MessDrive Bass Fuzz Pedal is made by ElectroniX. The manufacturer claims that it "make[s] the bass sound like how it should: A bass fuzz pedal that doesn’t kill the low end, in fact adds fat bottoms."
- The Microtubes B3K is made by DarkGlass Electronics. The manufacturer claims that it offers a range of sounds, ranging from "warm, clear, and punchy tube-like Overdrives, to devastating Raging Bass Distortions, all without losing a gram of low end or definition." Justin Meldal-Johnsen (Nine Inch Nails) praises its "big overdrive sound" and states that it is "highly recommended." A demonstration of the product on YouTube shows its wide range of sounds.
- The Photon Fuzz from FEA Labs uses "infrared light to control the fuzz distortion element."  Designed for "both bass and guitar players[,] [t]here are three controls for the fuzz and its level, with a 3-band EQ to shape the fuzz tone." As well, there is a "dry blend level control... for bass players and...an octave distortion level control."
- The Pickle Pie B Bass Distortion Pedal is made by Wren And Cuff. It has a "FET buffered active clean boost so you won't get any "drop-out" when you kick on the fuzz when playing live." As well, there is a "mid-scoop to help retain presence in a live playing situation".
- The Screamer Bass Fuzz pedal by Cusack Effects enables the player to "mix either the overdrive or the fuzz to your liking...from subtle grit to buzz saw." A reviewer noted the "build quality", with "mini chickenhead knobs [made] in house". The reviewer noted that it has a "Clip Selector: This allows you to select either the Standard, Crushed, or Assymetrical LED clipping." The reviewer noted how "noise-free the circuit is."
- The Supa Tone by Skreddy Pedals is a fuzz which can be used by bassists or guitar players. The manufacturer claim that when used for bass, it produces a "grindy, tubey distortion that stays in the pocket" and the player can add "as much low end as you like." As with many boutique pedals, there is a waiting list to obtain this product.
- The Super Bass Bit Fuzz by FX Doctor provides "thick, fuzzy low end...[and] a wall of compressed tone" and it can provide either harsh or mellow fuzz tone.
- The Woolly Mammoth fuzz bass from Z.Vex Effects is a hand-painted pedal with settings for output, equalization, "pinch", and "wool."
Overdrive built into amplifiers
Some bass amplifiers have an "overdrive" or distortion effect built into the unit. The Peavey Century 200 has an onboard "distortion" effect on the second channel. The Peavey VB-2 also has built-in overdrive. Aguilar Amplification's AG 500 bass head is a two-channel amplifier, one of which offers a "saturation" control for overdrive. A variety of BOSS combo amplifiers have a built-in "drive" effect. Gallien-Krueger's bass amp heads have a "boost" control which provides a simulated tube overdrive effect. The Behringer Ultrabass BVT5500H Bass Amplifier Head has a built-in limiter and overdrive. The LowDown LD 150 bass amp has a range of overdrive sounds, from a slight hint to heavy distortion. The CUBE-20XL BASS amp includes built-in overdrive.
The 75W Fender Rumble 75 Bass Combo Amp can produce an overdrive effect by using the gain and blend controls, giving overdrive sounds ranging from "mellow warmth [to] heavy distorted tones". The Fender SuperBassman is a 300-watt tube head which has a built-in overdrive channel. The Fender Bronco 40 includes a range of effects including modern bass overdrive, vintage overdrive and fuzz.
The MESA Bigblock 750 has a built-in overdrive channel. The Mesa M2000 has a high gain switch which can be engaged with a footswitch. The Marshall MB450 head and combo bass amplifiers have a tube pre-amp on the "Classic" channel which can be overdriven. The Ashdown ABM 500 EVO III 575W Bass amp head has a built-in overdrive effect. Overdrive is also available on many Crate bass amplifiers. The Yamaha BBT500H has three types of built-in drive effects: overdrive, distortion and fuzz. The Ampeg B5R Bass Amplifier has two channels: clean and overdrive, with the ability to combine the two.
Verellen, a boutique amp company, produces a bass amplifier with a built in overdrive channel.
The following section gives examples of songs that feature fuzz bass.
- The Polish death metal band Vader's song "Fear of Napalm", from the 2008 album XXV, begins with a growling fuzz bassline.
- Yellow Matter Custard, a Beatles tribute supergroup active from 2003 to 2011, credits Neal Morse with keyboards, guitars, vocals, and fuzz bass.
- One of the notable elements in the 2004 song "Staring at the Sun", by the American indie rock band TV on the Radio is its heavy fuzz bass line.
- Low, an American indie rock group from Duluth, Minnesota has used fuzz bass from their 2001 album Things We Lost In the Fire onward.
- On I Might Be Wrong: Live Recordings, a 2001 live album by English rock band Radiohead, the song "The National Anthem" has a hard "fuzz bass" guitar sound.
- British band Muse typically uses fuzz bass on most songs for a futuristic, progressive tone. Examples include Hysteria, Time is Running Out, and Uprising
- Ben Folds Five regularly employed fuzz bass to fill out the sound of a piano-led power trio. One example from the band's 1995 debut album is "Uncle Walter," where bassist Robert Sledge takes a fuzz bass solo.
- Nine Inch Nails' 1999 song "We're in this Together" uses fuzz bass.
- Marianne Faithfull's 1999 album Vagabond Ways credits Chris Thomas for fuzz bass.
- The Jesus and Mary Chain's 1994 songs "Sometimes Always", "Hole" and "Never Saw it Coming" from Stoned & Dethroned credit Jim Reid on fuzz bass.
- On the 1996 debut album by American indie rock band Neutral Milk Hotel, On Avery Island, Lisa Janssen is credited for fuzz bass on tracks 2 and 8.
- Motörhead's 1996 song "I Don't Believe a Word" from the album Overnight Sensation has a grungy fuzz bass intro.
- Ministry's 1996 song "Filth Pig" uses a mixture of regular bass with a fuzz bass layer over top of it (this can be heard about 25 seconds into the song).
- On Mouth To Mouth, the third studio album by The Blackeyed Susans, released in July, 1995, Phil Kakulas is credited with fuzz bass.
- Sloan's 1994 song "Snowsuit Sound" features a prominent fuzz bass tone not often employed in the band's catalog.
- Motörhead bassist Lemmy's bass sound has been called "fuzz-tone bass" by a music critic. In the mid-1980s song "Ace of Spades", his fuzz bass tone can be clearly heard. "Lemmy uses no effects pedals: the distortion is produced naturally by the valve [tube] amplifiers, [and] the high volume[, which] gives a classic valve, 2nd harmonic distortion."
- In the 1989 Elvis Costello song "Spike", Jerry Scheff is credited as playing fuzz bass.
- on Metallica's debut album Kill Em' All the song (Anesthesia) - Pulling Teeth is an instrumental bass solo by Cliff Burton featuring distorted bass and wah-pedal use; and Metallica's 1984 album Ride the Lightning features a short bass intro at the start of the song "For Whom The Bell Tolls" which features distortion and wah-pedal use.
- Grindcore band Extreme Noise Terror's song "Deceived" uses a grinding, distorted bass tone which can clearly be heard in the short bass intro at the start of the song.
- Frank Zappa's Apostrophe (') (1974) features "an amazing jam played by Jack Bruce with his fuzz bass, dirty and brutal as when he was in Cream."
- The 1971 progressive rockers Emerson Lake & Palmer featured buzzy fuzz bass on some songs on the Tarkus LP.
- In 1970, the Australian psychedelic and progressive rock band Tamam Shud released a song entitled "Goolutionites and the Real People", which credits Peter Baron on bass and fuzz bass. Two years later, Baron was also credited for fuzz bass for the song "Got A Feeling", which was penned for the surf film "Morning Of The Earth".
- In 1970, the funk/soul song (Don't Worry) If There's a Hell Below, We're All Going to Go begins with a woman proclaiming the virtues of the Bible's "Book of Revelation" over an introduction of fuzz bass and conga drums.
- Sir Lord Baltimore's Kingdom Come (1970) is "heavy psych/early stoner rock masterpiece with a totally fuzzed-out bass" 
- Inside Looking Out (1969) by Grand Funk Railroad features fuzz bass for several bass breaks mid-way through the song.
- The song Talk, Talk by Music Machine (1969) uses a growling fuzz bass
- Cream, Goodbye (1969): "Jack Bruce [during] his Cream period always used fuzz on his bass."
- Edgar Broughton Band's Wasa Wasa (1969); called the "best UK heavy psychedelic album ever, this ha[s] a lot fuzz on the bass." 
- The Litter's Emerge (1969) is "magnific heavy garage/psych/proto-punk with the typical 60's flavor but more heavier, with some pre-sabbathian atmosphere and a constant use of fuzz in the bass guitar" 
- The 1969 song Some Velvet Morning by Vanilla Fudge has a growly fuzz bass tone.
- In "Dance to the Music" (1968), by Sly and the Family Stone, bassist Larry Graham used growly, grinding fuzz bass for a bass break near the end of the song.
- The Genesis album In the Beginning (1968) has fuzz bass on the song "Mary, Mary"
- The Monkees song Valleri (1968) has fuzz bass.
- The United States of America (1968) has "spacey and experimental psychedelia with electronic, avant-garde, noise and proto-punk elements, with maybe, the best fuzz bass ever recorded."
- The 1967 song Sodding About by The Who has fuzz bass.
- The 1967 song "Zig-Zag Wanderer" from the album Safe As Milk by Captain Beefheart & His Magic Band starts out with regular bass, but then 2/3 into the song, the bass turns into fuzz.
- The 1967 Jefferson Airplane song She Has Funny Cars features Jack Casady on fuzz bass. Casady has an extensive fuzz bass solo, self-accompanied with chords, on a live version of the "Ballad of You and Me and Pooneil"
- The Beatles' 1965 album Rubber Soul features fuzz bass on "Think for Yourself." McCartney used a Vox Tone Bender to get this fuzz sound.
- The 1965 song Let's Hang On! by Bob Crewe, Sandy Linzer, and Denny Randell used two fuzz guitars: one guitarist playing low notes, another musician playing high notes on a fuzz bass.
- The 1965 Rolling Stones song "Under My Thumb" uses more novel instrumentation than that featured on previous Stones records including fuzz bass lines played by Bill Wyman.
- The 1961 Marty Robbins Country and Western song "Don't Worry" has a growly fuzz bass solo midway through the song, and a fuzz bass outro.
- The song features fuzzy, low-pitched guitar breaks. Some sources suggest this may be baritone guitar, rather than an electric bass.
- Zölzer, Udo; Amatriain, Xavier (2002). DAFX: Digital Audio Effects. John Wiley and Sons. p. 117.
- Brewster, David M. (2001), Introduction to Guitar Tone and Effects: A Manual for Getting the Sounds from Electric Guitars, Amplifiers, Effects Pedals and Processors, Hal Leonard, p. 18
- Holmes, Thom (2006). The Routledge Guide to Music Technology. CRC Press. p. 177. ISBN 0-415-97324-4.
- Case, Alexander U. (2007). Sound FX: Unlocking the Creative Potential of Recording Studio Effects. Elsevier. p. 96.
- Davis, Gary; Davis, Gary D.; Jones, Ralph (1989). The Sound Reinforcement Handbook. Hal Leonard. p. 112. ISBN 0-88188-900-8.
- Newell, Philip (2007). Recording Studio Design. Focal Press. p. 464.
- Dailey, Denton J. (2011). Electronics for Guitarists. Springer. p. 141.
- "Batt-O-Meter : Where to Buy". •Keith McMillen Instruments. Retrieved 18 September 2010.
- Hunter, Dave (2004). Guitar Effects Pedals: The Practical Handbook. Hal Leonard. p. 204.
- "What is True Bypass?". Dunlop News. Retrieved 18 September 2010.
- Black Cat Pedals Bass Octave Fuzz Pedal Review by Jordan Wagner www.premierguitar.com/Magazine/Issue/2011/Jun/Black_Cat_Pedals_Bass_Octave_Fuzz_Pedal_Review.aspx
- Album review: Motorhead, 'The World is Yours'. email@example.com
- Babiuk, Andy (2002). Beatles Gear. Hal Leonard. p. 173. ISBN 0-87930-731-5.