The legenday Klon Centaur

The Klon Centaur Professional Overdrive is a mythical guitar pedal invented by Bill Finnegan in the 1990s. Finnegan wanted to replicate the natural tube distortion sound of a cranked amp at lower volumes, without losing the harmonic richness of the amp. He found that the vintage TS9 Tube Screamer compressed the transient response of the original signal, had a midrange character he didn't like, and subtracted a noticeable amount of bass response from the signal. So, he set out to create a new type of overdrive that would bring the richness and dynamics of a cranked amp at lower volumes.

After several years in development, Finnegan and MIT graduate Fred Fenning invented the Klon Centaur Professional Overdrive, which became an instant critical success. The pedal was built by Finnegan's own hands, and the circuitry was a closely guarded secret. It remained uncopied for over a decade until its secrets were revealed to the world in 2008 when the schematics appeared online.

The Klon Centaur's drive control contained a highly unusual blend feature that combined clean and overdriven signal. This fixed the compression issue Finnegan had with the Tube Screamer. With the clean signal blended, the sound would retain the full dynamic range of the guitar, allowing for very natural picking dynamics. The pedal would also convert the 9-volt power supply to 18 volts, increasing the headroom. The Centaur also contains germanium clipping diodes, which offer a smoother and more harmonically rich distortion.

Another unusual feature of the Centaur is its hard clipping circuit, which is usually used in high gain distortion pedals. The Klon has plenty of gain on tap but never gets too harsh because of the blended clean signal. The Centaur is often described as a "transparent overdrive," meaning it doesn't alter the characteristic tone of the amp.

Finnegan stopped production of the Centaur in 2009, having hand-built an estimated 8,000 in its 15 years of production. Since then, it has become the most sought-after pedal in the world, finding its way into the hands of some of the world's best guitarists, including Jeff Beck, John Mayer, and Joe Perry. The Centaur regularly fetches over €7,000 on the second-hand market, and that figure continues to rise.