Tone Bender

The Tone Bender is the family of British fuzz circuits that Gary Hurst designed in London in 1965, and one of the first British-made fuzz boxes available to the public¹. Hurst started from the American Maestro Fuzz-Tone, modified it, and ended up with a circuit of his own that produced more sustain than its American counterpart²¹. Over the following decade the design went through several distinct versions, the MK1, MK1.5, MKII and MKIII, built and sold under the Sola Sound, Vox, Marshall and Colorsound names, and it remains one of the most copied fuzz circuits in modern pedal building.

For a player, what the Tone Bender circuit means is germanium fuzz with attitude: a raw, primitive character in the early versions³, more sustain and output as the design grew, and a Bias control on many versions that lets you tune the fuzz to taste. It is also the direct ancestor of the Fuzz Face, which makes it a foundational circuit in the same way as the Rangemaster or the Zonk Machine.

Where the Tone Bender came from: Gary Hurst and the Maestro Fuzz-Tone

The story starts with the Gibson-built Maestro FZ-1 Fuzz-Tone, the American fuzz of 1962. BLAMMO! Electronics describes the FZ-1 as having "started the Great British Fuzz Pedal Boom by inspiring Gary Hurst to modify Vic Flick's (the James Bond Riff guitarist) personal pedal into the Tone Bender"⁷⁸. JHS Pedals tells it the same way: "Building on the foundation of the American-made 1962 Maestro Fuzz Tone, Gary expanded what fuzz could do"⁸.

Hurst built his circuit from the back workbench of Macari's Musical Exchange on Denmark Street in London⁸. The UK fuzz box phenomenon began in 1965, when Hurst designed an effects pedal called a Tone Bender¹⁴. He approached the London retailer Sola Sound to market and distribute the pedal from their London store, Musical Exchange⁴. The MKI's three-transistor circuit was based on the Gibson Maestro Fuzz-Tone, but modified by Hurst to produce more sustain than its American counterpart¹.

The MK1: three germanium transistors in a wooden, then metal, box

The first Tone Bender, the MKI, was a three-transistor circuit⁹¹¹⁰. The earliest prototype units were housed in a primitive wooden box case, and the wooden-case models featured top and rear jack sockets along with level and bias controls, which let the user tune in their fuzz tone⁴. The circuit in those wooden-case models consisted of one OC75 and two 2G381 germanium transistors⁴.

During 1965 Hurst re-housed the Tone Bender circuit into a metal casing, commonly known as the MK1 Tone Bender⁴. He changed the construction material to steel to live up to the rigours of stage use¹. The early metal models featured hand-applied lettering covered with nail varnish to protect its fragility, in a flat gold finish⁴. The pedal sold for 14 guineas¹.

The germanium heart of the design is also its weakness. Mod Electronics, whose Tone Splendor MK1S kit recreates the circuit, notes that "the original MK1 design depended on the leakage current of its germanium transistors to function properly"³. That leakage varies from transistor to transistor, which is why no two vintage units sound quite alike. Mod Electronics describes the MK1 sound as having "a raw, primitive fuzz character which fits the early design of the original"³. Tru-fi's history of the circuit likewise identifies the Mark I as a three-transistor germanium design¹¹.

The MK1.5: a two-transistor rework

The MK1.5 is an unofficial name given to the transitional two-transistor circuit that followed the MK1¹³⁴. At its heart are two OC75 transistors¹⁴. These models were only produced for a short period⁴.

The MK1.5 matters far beyond its short production run. Red Witch Pedals calls it "Father of the Fuzz Face," because the Mk1.5 circuit inspired the Fuzz Face, which used different germanium transistors and had a much less tight bottom end¹⁴. RockBoard's PedalPedia likewise lists the Mk 1.5 as an inspiration for the Dallas Arbiter Fuzz Face¹³. So if you have ever wondered how the Fuzz Face came to be, the answer runs through this two-transistor British box.

The MK1.5 also has a documented place on record: it was the pedal used by The Beatles in Abbey Road Studio while recording Rubber Soul⁴.

The MKII: an extra gain stage for more sustain

The original Tone Bender MKII was released in 1966⁶, following the MK1 and the Mk1.5⁵. It is a three-transistor fuzz circuit, the version most famously associated with the Sola Sound Tone Bender⁶. Where the MK1's circuit was already modified for more sustain than the Maestro Fuzz-Tone⁹, the MKII pushed further, and BLAMMO! Electronics describes its own point-to-point MKII reproduction as "tuned for a bit more sustain and output volume"¹⁵.

The MKII is the version players most often chase today. ThroBak Electronics calls it "the fabled 3 germanium Sola Sound Tone Bender MKii Professional used by Jimmy Page and Jeff Beck," while noting that vintage units had inconsistencies that ThroBak's Stone Bender set out to tame¹⁶. BLAMMO!'s P2P Tone Bender MKii is a hand-wired point-to-point version of the circuit with top-mounted jacks¹⁵.

The MKIII and the later Colorsound Tone Benders

The MK3 brought a new punched metal casing, a circuit board and three OC75 transistors². The classic Tone Bender MKIII circuit was originally manufactured by Vox, Sola Sound and Colorsound¹⁷. Analog Man's Sun Bender MKIV manual describes the Sola Sound, Colorsound and VOX Tone Bender MK-III and MK-IV as three-germanium-transistor circuits with a TONE knob, and notes that some RotoSound and Park fuzz pedals also used this circuit¹⁸.

The 1970s saw the MK3 change from the traditional germanium transistors to more consistent silicon units². That change is the practical answer to the germanium problem: silicon transistors behave far more predictably from unit to unit, at the cost of the character germanium fans chase.

The versions side by side

Tone Benders made for Vox, Marshall and Rotosound

The Tone Bender also spread through OEM production. BSM's Bernd C. Meiser explains that Sola Sound built Hurst's circuit, slightly modified and in a large production number, as an OEM product for Vox, now called the Tone Bender (Mk1.5)¹⁹. The MKIII circuit, as noted above, appeared under the Vox, Sola Sound and Colorsound names, and in some RotoSound and Park fuzz pedals¹⁷¹⁸.

Pedals and kits based on the Tone Bender

The Tone Bender is one of the most cloned circuits in fuzz building, in every form from hand-wired reproductions to budget pedals and DIY kits.

Several builders treat the Tone Bender and the Fuzz Face as two halves of one sound²⁶²⁷¹⁹:

• Union Tube & Transistor's Tour Bender "takes aim at creating the legendary 60s tone of the Tone Bender and giving it an ability to clean up" like a Fuzz Face²⁶
• Their Sone Bender "took from the gain of a Tone Bender but the ability to clean up like a Fuzz Face"²⁷
• OKKO FX's Holy Grit is "based on the classic Fuzz Face/Tone Bender but heavily tweaked into something else"²⁸
• BSM's FuzzBender Fuzz Machine lets the user switch between Fuzz Face and Tone Bender (Mk1.5) circuits with a lever switch¹⁹

Hybrids go further. Jed's Pedals' Katzenkonig kit is "a Rat and a Tone Bender in one circuit"²⁹, pairing the British fuzz with the RAT distortion. And the family tree runs forward, too: the Maestro FZ-1 that inspired Hurst also led to the Zonk Machine created by John Hornby Skewes⁷.

What the bias knob does

Many Tone Benders, from the wooden-case prototypes onward, carry a Bias control⁴. On a Tone Bender Mk II style circuit like the SolidGoldFX Fuzzbox, "Bias adjusts the operating point of the third transistor"²⁰. Suhr's Brighton manual explains the principle generally: the bias control "adjusts the bias point of the transistor, which has a direct effect over the output waveform's shape and sound," with fully counter-clockwise as the standard setting³⁰. In practice, turning the bias knob moves the fuzz from smooth and saturated toward gated and spluttery, and on germanium pedals it is also the fix for transistors that drift with temperature.

The Tone knob found on the MKIII and later versions is simpler. Anasounds describes the Tone control on their Blues Believer, a Tone Bender-style fuzz, as adjusting "the treble response on the output of the pedal, adding extra presence in a very musical way"³¹, or more plainly, controlling the brightness of your tone³².

Who used one on record

The documented player list is short but heavy:

• Aclam Guitars' research on The Beatles' fuzz tones reports that Gary Hurst personally gave a Tone Bender MKI to George Harrison, "but Paul was the one who ended up using it"³³
• The MK1.5 was used by The Beatles at Abbey Road while recording Rubber Soul⁴
• Jimmy Page and Jeff Beck are associated with the Sola Sound Tone Bender MKII Professional¹⁶
• Jeff Beck's MKI use was reportedly hard on the hardware: due to his heavy use of the pedal, he smashed the unit with heavy foot stomping movements while playing on stage¹

What originals are worth

The MK1 sold for 14 guineas when new¹⁴. Today, Red Witch Pedals reports that Tone Bender Mk1.5 units "sell (on the very rare occasion they appear on Ebay or Reverb) for upwards of $5000"¹⁴. Wooden-case MK1 models are rarer still, with only a small handful produced⁴, which puts them beyond most players' reach and explains the healthy market in reproductions listed above.

Pedals on this page

Sola Sound Tone Bender MKI

Sola Sound · Fuzz

Dunlop Fuzz Face

Dunlop · Distortion

$149 list price

Maestro FZ-1 Fuzz-Tone

Maestro · Fuzz

Gibson Maestro Fuzz-Tone

Gibson · Fuzz

Mod Electronics Tone Splendor MK1S

Mod Electronics · Fuzz

Dallas-Arbiter Fuzz Face (pedal)

Dallas-Arbiter · Fuzz

Vox Tone Bender Professional MKII

Vox · Fuzz

Vox Tone Bender

Vox · Fuzz

Park Fuzz Sound

Park · Fuzz

Union Tube & Transistor Tour Bender

Union Tube & Transistor · Fuzz

$190 list price

BSM FuzzBender Fuzz Machine

BSM · Fuzz

Okko FX Holy Grit

OKKO FX · Fuzz

Catalinbread Katzenkonig

Catalinbread · Fuzz

$191 list price

Anasounds Blues Believer

Anasounds · Overdrive

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