Pro Co Rat

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Produced by Pro Co Sound, the Pro Co RAT is a classic guitar Effects pedal. The original RAT was developed in the basement of Pro Co’s Kalamazoo, Michigan facility in 1978. Numerous variations of the original RAT pedal are still being produced today.

The basic RAT has changed in appearance over the years, but its tone has remained largely the same. Pro Co has also introduced tonal variations of the RAT, including the Turbo RAT, You Dirty RAT, and Juggernaut Bass RAT.

The Pro Co RAT became very popular in the early 1980s, thanks in part to noteriety gained by its use by artists such as Jeff Beck and Joe Walsh. Since that time, the RAT has been used by some of the most influential and important guitarists in the world. This list includes John Scofield, Andy Summers, Thurston Moore, Kurt Cobain, and Johnny Greenwood.

1 History
2 How it works
3 Versions of the RAT
4 Popular Modifications to the RAT
5 Notable Musicians who have used the Pro Co RAT
6 External links

[edit] History

The origins of the Pro Co RAT can be traced back to the mid-1970s, when Pro Co engineers Scott Burnham and Steve Kiraly repaired and hot-rodded existing distortion pedals, such as the Dallas-Arbiter Fuzz Face. Burnham decided he could build a superior product from the ground up, and designed the RAT pedal.

In 1978, the RAT was being built as a custom-order product. Only twelve of these pedals, commonly referred to as the “Bud Box RAT,” were produced. Each pedal was built in an standard project box, hand painted, and hand drilled. By 1979, as the pedal became more popular, Pro Co began mass producing them. This iteration was built in a custom designed, rectangular sheet-metal enclosure. In 1984, Pro Co switched to a smaller, U-shaped enclosere. Finally, in 1988, the RAT 2 was introduced, which included an on/off LED. This model is still available today.

Other models of RAT products include:

Juggernaut (1979)
R2DU (1984)
Turbo RAT (1989)
Vintage RAT (1991)
BRAT (1997)
Deucetone RAT (2002)
Juggernaut Bass RAT (2003)
You Dirty RAT (2004)

[edit] How it works

The Pro Co RAT is a distortion pedal with a very simple circuit, based around a single op-amp the LM308. The distortion is produced using a variable gain circuit with diodes shorting the output to ground to produce hard clipping of the input waveform. This distortion stage is followed by a passive tone filter and volume control. This is exactly the same scheme as the BOSS DS-1 distortion pedal.

[edit] Versions of the RAT

Robert Strand's webpage lists the various RAT versions produced over the years. Pro Co also has a RAT History page on their website. A new Rat History page with pictures of different versions and more Rat History PageVersions include:

Current Product Line

Rat 2

Turbo Rat

Deucetone Rat

You Dirty Rat

Juggernaut Bass Rat

Discontinued Products

Non-RAT pedals that are produced by Pro Co

Pro Co Solo

[edit] Popular Modifications to the RAT

The RAT is a popular pedal for modifying. Some of the possible modifications include:

The Ruetz Rat mod which involves simply cutting one resistor to alter the tone. Gain is reduced somewhat and the bass is no longer attenuated. This can translate to thicker (fuzzier) bass response.
The Mighter Mouse mod involves a 3-way switch to select between Rat2 (clipping via OPAMP only), Turbo Rat (clipping via LEDs), and MOSFET clipping modes. It also shows an alternative to the Ruetz Rat mod using a potentiometer to replace the resistor instead of simply cutting it.
The original RAT pedals featured the LM308 IC which is now quite expensive. Recent Rat pedals now feature the Texas Instruments OP07DP. Other OPAMP ICs that people try include: NE5535A, LM741, TL071 FET-OP. Many install an IC socket to enable easy swapping of ICs.
2.1mm (BOSS style) 9vDC adapter socket mod. Because the tip on the BOSS style adapter is negative, one needs to install a plastic 2.1mm (switching) socket to avoid shorting out.