The Pro Co Rat pedal has been a staple on guitar player’s pedal boards since its introduction in 1978. This pedal is technically a distortion pedal, though its tones can push it right into fuzz territory; it might be thought of as a hybrid of the two. The story goes that, like so many great inventions, the final design of the Rat pedal was stumbled upon by accident. Designer Scott Burnham, creating the prototype in a rat-infested basement in Michigan, is said to have connected the wrong resistor to the circuit, which resulted in the op-amps overdriving extremely early, and creating a distortion tone that had never been heard from a pedal before. For the full history of the Rat, please see Josh Scott’s (of JHS pedals fame) video or article.
The Rat pedal has been through many iterations in its lifetime, from the original ‘bud box’ Rats to the first ‘filter’ Rats, to the Duecetone, Turbo Rat and the Brat. The modern production Rat looks similar to the classic mid-80s ‘small box white font’ Rat – the shape and looks most players probably consider the archetypal Rat. The question is does it sound the same?

The Rat has also been painstakingly recreated in digital form, most notably in our case by Universal Audio as the Raw plugin. The controls, box shape of the graphical user interface and logo font of the plugin name make this undoubtedly a Rat pedal emulation while avoiding any actual copyright infringement. Personally, I really enjoy the names different companies come up with for this: Guitar Rig 6 has the Cat, Line 6 have both the Rodent and the Ratatouille, Mooer have the Black Secret (complete with ‘vintage’ and ‘turbo’ switch), JAM has the Rattler, and Wampler have the Ratsbane. The giveaway on all of these is the ‘filter’ knob!


Have a look at the video to hear some of the examples.
The Rat pedal has distortion and volume controls, just as you’d expect, but also has its famous filter control. The filter is essentially a tone control, however, it works in the opposite way that we are used to insofar as all the way to the right results in a darker tone, and all the way to the left is brighter. The Rat also has a great mid-push to its sound as well, which is definitely what makes it such a favourite of so many players. A short list of players who have stepped on a Rat for their distortion tones includes Johnny Greenwood, Jeff Beck, John Scofield and Nuno Bettencourt – no slouches in that list, but extremely different styles and sounds!
The task at hand for us was to see whether there was a difference in sound between the original (a 1987 version we borrowed), a modern production (thanks to Pro Co and CMI Music) and the UA emulation. Trying a few different settings revealed that the three variations did in fact have slightly different tones – all very usable and all very ‘Rat-ish’, but also unique in their own way. The Raw was definitely the most mid-pushed tone, almost at times being in ‘cocked-wah’ territory. The vintage and the modern pedals were closer in tone to each other although had slightly different levels of gain and warmth to their tones. None of sounded bad – which is what made this so fun to compare! Whilst all definitely have their own thing, all three still felt like they were coming from the same place.
The advantages of the real thing might of course be the simplicity, the ability to use it with an amp, and of course being able to add it to your pedalboard. But the versatility of the plugin made it incredibly fun to explore. The plugin allows for stereo processing – both true stereo and dual mono – and also allows for multiple instances to be used at once. It allows for easy placement over the stereo drum or vocal busses in your mix without impedance issues or needing multiple real pedals, and the ease with which it could be quickly recalled and used made for hassle-free creativity.
As mentioned, all three had their own thing – and all three sounded great in different contexts. There is no reason why someone couldn’t have both (or even more different varieties) and use them extremely effectively.
Let us know any other comparisons you’d like us to make – keep an eye out for the upcoming comparison of an original Boss CE-1 chorus with some digital emulations as well!

