Keeley Fuzz Bender

The Keeley Fuzz Bender is a five-knob fuzz pedal from Keeley Electronics, first shown at NAMM in January 2019 and officially released that April¹². It is Robert Keeley's take on the Tone Bender, the British fuzz format that dates back to 1965, updated with a three-transistor hybrid circuit and an active EQ section that most vintage-style fuzzes do not have³.

The circuit combines high-gain silicon with germanium, built around vintage Japanese germanium transistors, and the maker describes the result as "monumental fuzz tones" ranging from fat square waves to angular fuzz to glitchy, velcro-like attacks⁴¹. What sets it apart from a straight vintage clone is the tone shaping: a two-band active EQ sits after the fuzz circuit, giving more than 20dB of boost or cut at 100Hz and 10kHz⁵.

What it does: a hybrid silicon and germanium Tone Bender

The Fuzz Bender is an extreme evolution of the Tone Bender format rather than a copy of it. Guitar.com named it among the best effects pedals of 2019, noting that "with the Fuzz Bender, Robert Keeley has made some serious updates to the Tone Bender format"⁸. Delicious Audio's buying guide describes the topology plainly: the Keeley adds an active EQ after the three-transistor fuzz circuit for added versatility⁹.

The hybrid transistor design is the heart of it. Delicious Audio explains the reasoning: "It's a three-transistor hybrid fuzz utilizing the higher gain of silicon and the warmer sound of germanium circuitry"¹. Guitar World's news coverage put it the same way at launch, describing a combination of high-gain silicon and silky smooth germanium producing wild fuzz tones⁵.

For a player, that mix matters because pure germanium fuzzes are warm but can be inconsistent and low-output, while silicon fuzzes are aggressive and stable. The Fuzz Bender aims for both characters in one box, combining silicon and germanium fuzz stages, and the bias control widens the range further⁵⁷⁶.

Controls: five knobs, including the bias

The control set is Level, Fuzz, Bias, and the two EQ knobs. Guitar World notes that the medium-size enclosure, about the size of a Phase 100, lets Keeley fit large knobs for the Level and Fuzz controls that can be adjusted with a foot mid-song⁷.

The Bias control is the one reviewers keep coming back to. Guitar.com's Michael Watts wrote that it "modifies the character of your fuzz, between square-wave flavours and sawtooth chaos," and that rotating it clockwise "brings out more spitty, spluttering voltage-starved flavours which work particularly well with a bridge humbucker"⁶. JHS Pedals' write-up was even more direct: "The bias control on this pedal is straight-up wild. You can go from full distortion to dying hyena sounds in a few seconds"¹⁰.

Active EQ: 20dB of boost or cut at 100Hz and 10kHz

The EQ is what separates the Fuzz Bender from most Tone Bender-style pedals. It is a two-band active EQ, bass and treble, built using two gyrators, and it offers over 20dB of boost or cut at 100Hz and 10kHz⁵. Delicious Audio calls it "an active EQ with a massive 20dB of boost or cut available for the highs and lows, for truly extreme tone shaping," and explains that using gyrators as an active EQ gives the ability to create massive fuzz tones not possible with typical square-wave circuits¹.

Guitar.com's review went further on how it behaves in practice:

Michael Watts, Guitar.com⁶

He also found that the treble voicing is focused around 10k, and the more you boost it, the closer it gets to an octave effect, which points the pedal toward octave-fuzz territory at extreme settings⁶. The same reviewer concluded that the amount of push on offer makes for a hugely versatile unit⁶.

How it sounds compared with a Big Muff

The Fuzz Bender is a Tone Bender derivative, not a Big Muff, but the comparison comes up because both are thick, sustaining fuzzes. Watts addressed it directly: with the bias fully counterclockwise and the other knobs at noon, the pedal is "Muff-like in character, but with more definition than the average Pi, it's confrontational but controlled"⁶. MusicRadar's reviewer described it as "a high quality, similarly tweaked and adjustable version of the Tone Bender circuit which started it all"¹¹.

Players comparing fuzzes may also want to look at the JHS Legends of Fuzz Bender, a different maker's take on the same vintage circuit family.

History: a NAMM debut and the Mono Black Limited Edition

The Fuzz Bender was one of four new pedals Keeley presented at NAMM 2019, and according to Delicious Audio it was probably the most hyped of the bunch¹. Guitar.com reported in April 2019 that "the hairiest of the lot, the Fuzz Bender, has now been officially released"². Later that year it placed 11th in Delicious Audio's readers poll about the best stompboxes of 2019¹.

The original circuit it draws on goes back further: the Tone Bender MkI was released in 1965 by a London store as their version of the first fuzz pedal ever, the Maestro FZ-1³.

Keeley also issued a Fuzz Bender Mono Black Limited Edition, a limited-run version of the same five-knob, three-transistor design using the same combination of high-gain silicon and silky smooth germanium⁴.

What reviewers said

Published reviews were consistently positive:

• Guitar.com (Michael Watts, 2019): "A sensational, versatile fuzz which will appeal to connoisseurs and novices alike." He singled out the active EQ as the standout feature⁶.
• Guitar World: concluded that the Fuzz Bender "will likely end most guitarists' search for the perfect fuzz pedal," crediting its versatile EQ and bias controls⁷.
• Guitar.com's best effects pedals of 2019: included it in the year's awards coverage for its updates to the Tone Bender format⁸.
• Delicious Audio: readers voted it 11th among the best stompboxes of 2019¹.

Michael Watts, Guitar.com⁶

At $149 USD, it sits in the mid-range for feature-rich fuzzes, and Guitar.com's 2024 Warm Bender review still referenced it as "a good affordable germanium fuzz option"¹².

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