The Klon Centaur is an overdrive pedal made by Bill Finnegan in the USA. Finnegan was a gigging guitarist in Boston in the late 1980s in search of a way to get to the cranked sweet spot of his tube amp at lower volumes in small venues. Many guitarists in the early 1990s were using the Ibanez TS9 and TS808 pedals for this purpose but Finnegan found them lacking in bass response and mid-range character. Finnegan set out to create his own pedal with the help of a friend and recent MIT electrical engineering graduate. They worked on the design in their spare time and had a working prototype within a year. Finnegan was still not satisfied and they kept tweaking the design. His MIT friend moved away so Finnegan enlisted the help of another MIT graduate electrical engineer, Fred Fenning (who was tragically killed in a plane crash in 1997, aged 44).

By 1994 Finnegan was ready to sell his Klon Centaur pedals and set up a one man operation to build, test and ship each one. The originality and popularity of the pedal meant he was soon very busy because its design was very labor intensive. It had a custom cast enclosure, the knobs and potentiometers were also custom made. These pedals were made from 1994 to 2009 with around 8000 made in total. The retail price of the pedal from 2002 to 2009 was $329, however these pedals took on a mythical status and began to sell for thousands on the secondhand market. This price inflation happened even before they were discontinued, because there was a 12 to 14 week waiting time for a new one, so people were going to the used market instead. Finnegan who was still selling them at the much lower retail price, felt this was unsustainable and he discontinued the Klon Centaur.

The Klon Centaur's original circuit was encased in epoxy resin - for mechanical protection but also to protect Finnegan's design from being ripped off. In 2009 the community at freestompboxes.org bought a Centaur and sent it to Martin Chittum to analyze. He removed the resin, traced the circuit and identified of the components and the schematic was now available for others to copy. Many other manufacturers have now released pedals that replicate the Klon Centaur, to a greater or lesser degree and there are even DIY Centaur kits begin sold.

In 2008 Finnegan began a new overdrive pedal design that would be more cost-effective to make, and in 2014 the Klon KTR was released. The KTR uses mainly surface mounted components and has no hook-up wires. The modular foot switch part can be easily replaced if needed. It is also much more compact than the original Centaur.

Source: KLON Siberia website (archived 2003)

Source: Bill Finnegan interview. Premier Guitar. (January 21 2014)

Source: All About The Klon Centaur: Clones, Schematics, History, Kits (October 9, 2020)