The ProCo RatBuying Guide

Sort through the many vintage and new Rat distortion options.

In the pantheon of guitar pedals, the ProCo Rat sits alongside the Electro-Harmonix Big Muff and Ibanez Tube Screamer as one of the true archetypes of guitar and bass dirt. Like those other pedals, the Rat pedal has spawned countless variations and imitations over the decades, and anyone seeking its searing brand of distortion has more than a few options to consider on today's pedal market.

Dating back to 1978 and the work of Scott Bruhan and Steve Kiraly, the life of the Rat began, as is the case with many other pedals, as a custom order project. And since then, the main production Rat has been updated and altered many times, with new enclosure styles and various component swaps. A notable change, for example, came in the form of a switch from a LM308 to an OP07DP op amp chip in the early 2000s.

Through every iteration, this classic stompbox has maintained its well-earned reputation for being diverse enough to deliver everything from metal-primed distortion wallop to a more subtle overdrive and thicker, fuzz-like tones.

If you're considering adding a distortion pedal to your rig, the Rat is a great starting point. Take a look at our guide below for an overview of the various old and new Rat options currently available on Reverb.


ProCo Rats Still in Production

Vintage ProCo Rat Pedals

From a circuit design perspective, the Rat is actually a rather simple pedal featuring, basically, a distortion stage, a tone control, an output stage, and power supply (for more on the circuit of the Rat, check out this article on from Electro Smash. The basic Rat recipe has been altered at different points in its production history, which has resulted in a multitude of variations—some of which are highly sought-after on the used market.

For the first couple of decades of Rat production, the circuit was based around an LM308 op amp made by Motorola. In the early 2000s, ProCo replaced this with a more easily accessible OP07DP. While the audible differences are not hugely apparent to most, many consider the newer chip to sound a bit brighter and clearer. Others prefer the warmth of the earlier design, making LM308-stocked Rats more collectible and expensive on the used market. Often, you'll see the inclusion of this chip advertised by sellers in the title of their Reverb listings.

The components used in the gain circuit that produce the Rats particular style of hard clipping have also varied through different eras and specific models. The Rat 2, which came out in 1988, replaced original 1N914 with 1N4148 diodes. Other Rats, like the aforementioned Turbo Rat, have used higher-octane red LEDs, while the "You Dirty Rat" model uses germanium-based diodes.

The sonic differences that these component variations make are ultimately subjective, and what makes one worth more than the other has just as much to do with their historical reputations and associations as they do the actual sound that they produce.

Hear a ProCo Rat 2 from 1988 in action.

Key Vintage Rat Variations

Other ProCo Rat Offshoots and Iterations

The Often-Imitated Circuit of "The Rat"

As with many other classic designs, the latest generation of boutique pedal builders has used the Rat as something of a template on which to build a vast array of Rat-like distortion pedals. Most of these seek to emulate the sound of that early-'80s generation of Rat pedal, while others add new utility to the core circuit. Take a look at some of our favorite Rat-like pedals below.

Popular Rat Modifications

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Editorial content by Evan Weiss