Zvex Woolly Mammoth

The ZVex Woolly Mammoth is a fuzz pedal made by ZVEX Effects, a company that has been building effects pedals and amps for guitar and bass since 1995¹. It was designed for bass first, but ZVEX describes it as "a favorite for guitar," and says of it: "this incredibly sub-frequency-preserving unit will hold on to the lowest lows like no fuzz ever heard before"². The circuit also has a frequency response that continues several octaves below what we can hear³.

What sets it apart from most fuzzes is that the bottom end stays solid when you kick it in. Analog Man's page for the pedal says bass players "have never heard such shocking subs from a pedal before" and describes the tone as "the classic 60's/70's artillery-fire tone"⁴. The pedal also includes a gentle gate for silencing your instrument between notes or phrases².

The controls: Output, EQ, Pinch and Wool

The Woolly Mammoth has four knobs, a layout the Germanium Mod version keeps as "the classic ZVex layout with controls for Output, EQ, Pinch and Wool"⁵. Analog Man notes that starting in July 1998 an EQ knob was added for a total of four knobs, at a slightly higher price⁴.

The EQ is a "muff-like eq knob that lets you tune in exactly how much high end goes through your DI box," and the pinch knob "mutes any hiss and noise when you stop playing," working alongside the built-in gate⁴. On the Germanium version, Guitar.com describes the EQ knob as refining your tone in the mix, "from giving your mids a boost to emphasizing the lows"⁷.

A bass fuzz that keeps the low end

The Woolly Mammoth's reputation rests on its low end. ZVEX's own copy promises it will "hold on to the lowest lows like no fuzz ever heard before"², and The Guitar Pedal Directory says it is "loved by guitarists for its ability to maintain deep, subby low end while delivering rich, textured fuzz"⁶. Gearnews notes it is "often used for mammoth riffs and bass-heavy tones" in the psychedelic stoner rock world⁵.

The circuit draws less than one-half of a milliampere, which Pedal of the Day calls "unheard of in the effects pedal world"³. Analog Man puts that at one-hundredth the current consumption of most commercial pedals⁴.

Does it work on guitar?

Yes, and reviewers have been clear about it. Pedal of the Day wrote in 2017: "Today's bass-oriented fuzz sounds incredible on guitar, with a tremendous bottom end beautiful harmonic structure for any six-string machine to bond with"³. The same review concluded that the pedal offers "a ton of crazy and innovative sounds, with a versatility to sound excellent on a slew of instruments"³.

History and versions

The circuit was designed by Chuck Zwicky⁴. In a 2024 JHS Pedals interview, Josh Scott credits Zwicky directly: "he designed the circuit for the woolly mammoth that's his invention"⁸. Analog Man's page, which dates to the pedal's early years, records the July 1998 addition of the EQ knob and notes the pedal later gained a power jack and LED⁴.

The Woolly Mammoth has appeared in several versions over the years:

• Hand-painted Woolly Mammoth: The standard version, hand painted with colors and details that may vary, listed at $399.00 as of October 2026².
• Woolly Mammoth Vexter: Uses the same high-quality components as the hand-painted versions but with silk-screened artwork for a more affordable price, listed at $279.00⁶⁹. ZVEX's page lists it as sold out as of October 2026⁹.
• Woolly Mammoth 7: An expanded version released for the 2015 holiday season, adding a Marshall-style tone stack with Bass, Mid and Treble controls plus independent volume controls for EQ on (Vol 1) and EQ off (Vol 2)¹¹⁰. The hand-painted version was priced at $499¹¹. With the EQ off, the fuzz is more linear with pronounced mid frequencies and "has its own unique voice" compared with the standard pedal's single tone knob¹.
• Germanium Woolly Mammoth Mod: A limited edition announced in July 2018, built with rare "spam can" germanium transistors in place of the silicon-based circuit¹²⁷. It lists for $299¹³. MusicRadar says it promises to be "highly responsive to pick attack, with distortion overtones reminiscent of a Fender Rhodes or Wurlitzer keyboard"¹³, and Gearnews reports it gives more attack and more bottom end in the bass range, addressing the sluggishness some players found in the regular version⁵¹³.
• Sylvia Massy Woolly Mammoth: A special edition of 60 units, each hand-assembled and hand-numbered, with UV-printed artwork by record producer and artist Sylvia Massy and hand-selected NOS 2N2222A transistors, listed at $399.00¹⁴.
• Custom-shop runs: ZVEX's custom store has offered numbered Woolly Mammoths (U015, U018) whose parts are otherwise identical to the standard pedal, now sold out¹⁵¹⁶, and a WM2219 experiment built in a sample Sylvia Massy enclosure with large, round tuna can 2N2219 silicon NPN transistors, in a package similar to the stock Fuzz Factory 2N404¹⁷.
• Screaming Females run: In 2019, Marissa Paternoster of Screaming Females teamed up with Zvex to create a limited run of Woolly Mammoth pedals featuring her original artwork¹⁸.

On the Germanium version's character, Guitar.com wrote that "you'll be able to achieve a warm, vintage-y fuzz that works just as well for electric blues leads as biting punk riffs"⁷.

Players comparing ZVex fuzzes can also look at the ZVEX Fuzz Factory, the company's best-known fuzz, and the ZVex Mastotron, another bass-friendly fuzz in the lineup.

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