Rat Distortion

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Overview

Rat Distortion is a brand associated with the Pro Co RAT, a distortion pedal originally developed by Pro Co Sound in 1978-1979. It produces variations of the original RAT circuit, known for its op-amp-based hard-clipping distortion using components like the LM308 or OP07DP op-amp and diode clipping. The pedal has achieved widespread use across rock, metal, and other genres due to its high-gain, harmonically rich tone resulting from a design error in resistor value.¹²⁴

History

Pro Co Sound was founded in 1974 by Charlie Wicks in Kalamazoo, Michigan, after the closure of The Sound Factory. Engineers Scott Burnham and Steve Kiraly developed the original RAT pedal in 1978 in the company's basement, with mass production starting in 1979; a key circuit feature arose from Burnham installing a 47 ohm resistor instead of 470 ohm.¹²⁵ Numerous versions of the RAT have been produced continuously since, establishing it as one of the best-selling guitar distortion pedals.¹³

Product Lines

Product Line	Positioning	Price Range
The RAT (standard distortion pedal)	classic high-gain distortion	$80 - $100
Turbo RAT (modified gain structure)	enhanced turbo mode distortion	$100 - $150
You Dirty RAT (diode-modified variant)	versatile clipping options	$100 - $150
RAT 2 (modern update)	updated circuit with op-amp options	$90 - $120

Manufacturing

Original RAT pedals were developed and initially produced in Kalamazoo, Michigan, USA.¹² Current manufacturing location for Rat Distortion products is not specified in available sources; production involves standard pedal assembly with specific op-amps like LM308 or OP07DP.⁴

Notable Products

Pro Co The RAT - Original 1979 distortion pedal with Distortion, Filter, and Volume controls using LM308 op-amp.
Turbo RAT - 1989 variant adding a turbo footswitch for increased gain.
You Dirty RAT - 2001 model with switchable clipping diodes for tone variations.
RAT 2 - Updated version with OP07DP op-amp and improved noise floor.

Reputation

The RAT is regarded by guitarists as a landmark distortion pedal for its versatile, aggressive tone suitable for rock, metal, and beyond, with a simple circuit that allows extensive modification.¹²⁹ Enthusiasts value its heritage and the unique sound from its accidental high-gain design, though some note it can become noisy or fizzy at extreme settings.⁴⁵ Professionals praise its enduring popularity and presence on countless recordings.⁷⁸

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