KLON Centaur

The Klon Centaur is an overdrive pedal designed and hand-built by Bill Finnegan of Klon, produced from 1994 until production of the original ended in 2008¹²³. Finnegan set out to design an overdrive that could realistically recreate the harmonic content of a pushed tube amp, after finding himself playing Fender amps like the Twin too loud in bars and clubs²⁴. Around 8,000 units were made, each built, tested and shipped by Finnegan himself, and the circuit was covered in black epoxy resin to stop reverse engineering¹⁵³.

The Centaur became one of the most collectible pedals on the market. Guitar World's explainer calls the originals "the most collectible pedals on earth," with secondhand units fetching $10,000 or more⁵.

What the Klon Centaur does to your sound

The Centaur blends an overdriven signal with a clean, filtered signal, which is the heart of its reputation. Its gain control potentiometer has two sets of legs controlling different parts of the circuit, blending the overdriven tone with the clean signal¹⁰. On That Pedal Show, Dan explained that the gain pot is a dual-gang pot: one wiper controls gain on the distortion circuit while the other mixes between the distortion and clean circuits⁴.

With the gain control all the way down, the distortion part of the circuit is effectively turned off, which is why many players use the Klon as an always-on pedal with the gain dialed down, for clean boost and gain stacking¹¹. Brian Wampler told MusicRadar the pedal was originally designed to be used with tube amps already breaking up, rather than with a clean amp¹¹. GuitarPlayer describes it as "incredibly versatile. An always-on sweetener, boost, drive, and great gain stacker with other pedals"¹².

The circuit uses hard-clipping to ground, with the core built around the TL072 op amp, two of which handle four stages of input conditioning and gain¹³¹⁴. The tone control is an active high-pass shelf above 400Hz that boosts and cuts treble rather than only cutting¹⁴.

On That Pedal Show, Dan and Mick traced the Centaur's origin and its controls, including the dual-gang gain pot and the 10K master volume pot at the end of the circuit⁴.

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The controls: gain, treble and output

The Centaur keeps its control set minimal: gain, treble and output⁷. On That Pedal Show, Mick noted that with only a treble pot plus gain and output, control over headroom and gain is very basic¹⁶.

The enclosure is a heavy die-cast box, larger than common Boss or Ibanez pedals, and the buffer stage drives additional pedals without tonal loss, per the Legendary Tones reviewer's listening test⁷.

Power: 9V doubled to 18V inside

The pedal takes a standard 9-volt power supply and internally doubles it to roughly 18 volts, giving the circuit more headroom than a typical 9V overdrive². A 9V DC jack is included, but it is the 1/8" plug type rather than the standard 2.5mm barrel, and a male plug is included for retrofitting another DC adapter⁷.

History and versions: gold, silver and the horsie

Finnegan developed the Centaur from 1990 to 1994 in partnership with two MIT engineers, a process that took around four and a half years⁵¹⁷. The first unit, the Centaur 002, was built in January of 1995 and was the first Klon ever built and sold⁹. The original sales receipt said $285.00⁹.

The Centaur came in silver and gold finishes, with no horse, short-tail or long-tail graphics, plus a gold version with white font; the circuit is the same across versions¹⁸. The Silver Edition differs from the gold in a few component values, including a 560p cap where the gold uses 820p, and resistor changes around the gain and treble stages that give more gain, increased volume and treble for the clean signal, and a slight increase in overall brightness¹⁹.

Production of the original ended in 2008, the same year the circuit was reverse-engineered using specialized solvents and X-rays, with the schematic posted online²¹. Finnegan later built the Klon KTR, an updated, reimagined version produced in larger numbers, with a selector switch for true-bypass mode¹⁷²⁰. He has also built new Centaur Professional Overdrive units, hand-built and fully tested personally, with his remaining NOS diode stock reserved for those builds²¹²².

On the JHS Show, Josh Scott walked through the versions, the hype and the used market⁴:

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What a Centaur sells for

Finnegan jokingly tried to sell his #002 unit for $500,000, and in 2024 he gave a newly built gold unit to a longtime friend to auction on eBay, with every penny after fees going to her²⁴²². Guitar World's view is that the originals "have become rare collectibles, not necessarily tools for the trade," and that their value will keep rising as long as Finnegan no longer builds them⁵.

Who uses it

The Centaur's topology became a template for other builders. Josh Scott calls the Klon clone "the new tube screamer," noting widespread cloning by 2010²³, and the market now includes the Behringer Centaur, the EHX Soul Food and the Wampler Tumnus, a miniature version of the circuit²³.

The Behringer lawsuit

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