Foxx Tone Machine

The Foxx Tone Machine is an analog fuzz pedal with a built-in octave-up mode, first released in 1971 and designed by Steve Ridinger¹². A single switch takes it from a standard fuzz to an octave-up fuzz, and Guitar Player's Dave Hunter describes it as one of the most expressive and more extreme fuzz boxes of the 1970s, a circuit that offered more control than the average Fuzz Face or Maestro clone².

What made it stand out was that octave. Where most fuzz pedals of the era, like the Fuzz Face or Tone Bender, stopped at saturated distortion, the Tone Machine added a note an octave above the fundamental, in the territory of the Octavia. Guitar Player's history of the pedal calls it the fuzz of choice for Peter Frampton, Billy Gibbons and Adrian Belew³.

Where the Tone Machine came from

Steve Ridinger created the Foxx pedal line in the 1970s and priced the Tone Machine at $49⁵. Production began in Los Angeles: some of the very early Tone Machines were made in North Hollywood, with most made in Chatsworth from the summer of 1972 onward⁶. TONEHOME's reference page records the pedal as made by Ridinger Associates Inc of Chatsworth, California, in the early 1970s, produced from the early to mid 70s and re-issued in the 2000s¹.

The pedal's look was as distinctive as its sound. It wore a unique velour treatment on the housing, a flocked finish that came in red, black and purple and was, reportedly, a pain to apply⁶. That finish, and the octave-up sound, are what most players recognize the pedal by today.

How the circuit works: four transistors and an octave-up phase splitter

The Tone Machine used four transistors and had a very effective octave-up sound². The octave generation is the heart of the design: the stock Tone Machine uses a phase splitter with diode rectifiers to produce the octave-up effect⁷. In plain terms, the guitar signal is split into two opposite-phase copies, then a pair of diodes rectifies them so their peaks align; what comes out is a waveform dominated by a component at double the original frequency, which the ear hears as the note an octave up.

The transistor choice is undemanding by DIY standards. General Guitar Gadgets' replica kit specifies 2N3904 or other NPN bipolar transistors for all four positions, Q1 through Q4⁸. The original also used orange drop caps and other large size film caps for the non-electrolytic capacitors⁸.

Compared with its contemporaries, the circuit is on the complex side. A Tone Bender MK-III or MK-IV used three germanium transistors and a tone knob⁹, and the Univox Super-Fuzz took a different route to its octave. The Tone Machine's four silicon transistors, fuzz and tone shaping, and switchable octave gave it more control than the average Fuzz Face or Maestro clone of the time².

Guitar Player's reviewer also judged the octave-up effect to be a major bonus that performed better than many other octave and octave-fuzz units on the market².

The controls and the octave toggle

The control panel is simple: three knobs and a switch. TONEHOME's page lists them as Tone, Gain and Volume¹, while Guitar Player's Art Thompson interview with Steve Ridinger describes volume, sustain and fuzz (tone) controls plus a toggle switch to turn the octave on and off⁶.

The octave switch is the pedal's signature control. On the original it was labeled "Octive" on the control panel, misspelled, though corrected in the brochures². The 2005 reissue replaced the toggle with a metal toggle switch described as adding an octave above the fundamental tone, "a la 'Purple Haze'"¹⁰, and a later Danelectro version moved the function to a footswitch¹¹.

Versions: velour colors, Stars & Stripes and the reissues

Original Tone Machines came in a big range of colors. TONEHOME notes that purple, blue and red are the most popular ones, with white and US/stars and stripes versions the rarest of all¹. The Stars & Stripes unit from 1972, finished in red-white-and-blue flocking, is among the rarest, because the masking needed for the multi-color flocking was laborious and very few were made².

The pedal was also sold under other brand names: Turtle, Sears Roebuck & Co., Nashville, Paraclete and Emmons among them¹. The best known of these OEM versions is the Ibanez No. 91 Tone Machine, made by fOXX in California in 1974 and 1975, which TONEHOME identifies immediately as a Steve Ridinger Associates made fOXX Tone Machine with mere OEM branding¹². A prototype Ibanez Tone Machine surfaced for sale in 2019 at $20,320.55, which gearnews described as a super simple circuit but a pretty rare edition¹³.

The reissue history runs in two waves:

• A Foxx-branded reissue in the 2000s, which Guitar World's Trevor Curwen recalls as an official reissue from 2005, when the brand was revived in its original battery-only flocked form¹¹². Guitar Player's Barry Cleveland reviewed that reissue at $249 retail and $199 street, calling it an authentic re-issue of the early-'70s original¹⁰.
• Danelectro's 3699 fUZZ, in which Danelectro owner Steve Ridinger, the original designer, brought back his circuit with some important tweaks, including an added footswitch for the octave effect⁵¹¹.

The same circuit under other names

The Tone Machine circuit has had a long afterlife in other makers' pedals. Danelectro's French Toast was based on the original Tone Machine², and the Danelectro 3699 Octave Fuzz is based on the 1972 Foxx Tone Machine¹⁴. Pedal of the Day describes the 3699 fUZZ Octaver as bringing back the original FOXX Tone Machine circuit with tweaks¹⁵.

Several current makers trace their octave fuzzes to the same design:

The FOXX and TONE MACHINE trademarks are held by Mark Simonsen, who is not affiliated with Danelectro⁵.

Building one: schematics and kits

For players who want the circuit rather than the collectible, the Tone Machine is one of the more accessible vintage fuzzes to build. TONEHOME hosts a downloadable fOXX Tone Machine schematic¹. General Guitar Gadgets sells a replica kit, referred to as FTM in its documents, using 2N3904 or other NPN bipolar transistors and a 9 volt battery, not included in the kit⁸. Madbean Pedals' Wolfshirt is a documented PCB project based on the Foxx Tone Machine⁷, and Aion FX's Obscura takes the octave section of the fOXX Tone Machine, with a few value tweaks, and adds a clean blend and a knob to change the character of the effect¹⁹. Aion FX also notes that Prescription Electronics' COB octave section is clearly based on the fOXX Tone Machine with a few value tweaks¹⁹.

Pedals on this page

Dunlop Fuzz Face

Dunlop · Distortion

$149 list price

Foxx Tone Machine

fOXX · Octave and pitch

$49 list price

Danelectro 3699 Fuzz

Danelectro · Fuzz

$199 list price

Danelectro DJ-13 French Toast Octave Distortion Mini

Danelectro · Distortion

Danelectro 3699 fUZZ Octaver

Danelectro · Fuzz

Prescription Electronics COB

Prescription Electronics · Octave and pitch

$299.95 list price

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