ProCo RAT 2

The History lessons continue. The year is 1977 or 1978, and distortion circuits like the DOD250 and the MXR Distorition + have been around for a bit. ProCo Employee Scott Burnham, whose official job title was “Hippie in Charge of Technology” (according to thejhsshow.com) had spent a while repairing and modding drive circuits had put it on himself to create a new and better one, and he stumbled upon what became known as the RAT circuit by a happy accident. When soldering parts, he placed a wrong resistor in front of the operational amplifier – 47 Ω instead of 470 Ω. This led to the OPamp itself clipping its rails and to a unique sound that has never been experienced by human ears before. A new pedal was born. It was a gnarly sound they were after and they needed a good name for it, which was quickly found – inspired by the rodents infesting the basement they were working in.
From that point to the present day, a lot more than a dozen versions of the RAT have come out.
For the pedal community, one drastic change was that the LM308 OPamp was replaced by the OP07.
Some say, only a RAT with an LM308 is a true RAT while others wave graphs that compare the two chips and show that they are identical, claiming that literally any other part change inside the RAT has more impact on the sound than the LM308 / OP07 swap.
I myself wanted to stay on the frugal side of things and simply bought a current production model, so we’re looking at a Chinese made RAT 2 with OP07 chip.
The pedal feels quite heavy. My guess is that the bulk of the weight is caused by the healthy wall thickness of the enclosure. The knobs are made of plastic that does have a cheap feel to it and they could be marked better to see their positions, especially in stage light, but the pots offer a good amount of friction and it does not feel like any accidental changes of knob position might occur through bumping the pedal or brushing along its side with a cable. The graphic printed along the knobs’ travel allows for precise adjustments.
One thing about the underside of the pedal:
There are huge rubber feet screwed in, which give the pedal a certain clearance off the ground. That clearance is needed because they used an allen screw with a huge head to hold the battery compartment closed. They sure do hope that my pedalboard has rails and I place the RAT so that huge bulk of a screw head can go between the rails.

Apart form that, it is a little higher and a little wider than your average pedal, but hey, it’s a classic. You don’t argue about those – especially when they come with top mounted jacks.

Playing the first notes, I can immediately see how this rodent takes things a step further than the classic distortion units that came before it. It’s not only more gnarly, but also much richer in harmonics.
That makes it more useful in low gain settings, and of course unleashes a swarm of bloodthirsty locusts on your ear canals when you run it higher. Luckily, there is the filter knob to aid you, should the prickling sensation on your ear drums be too much.
If you’re used to low gain Overdrive and tube saturation, playing a cork sniffer’s pedal and amp collection and try out the RAT by itself, you might get the impression that you ran across a pocket calculator that fell upon hard times (meth addiction, leaking battery, crack in the solar panel) a while ago and now, for some obscure reason is so livid with you, it’s literally foaming and trembling.

All that anger is good, but it’s also not the product of an “organic” contraption like a tube amp that is pushed hard and in turn pushing the cabinet hard. 
The RAT is not trying to emulate any of that. It gets you hard clipping from a microchip and a diode, two components you can place on your thumbnail and still have room to spare, given your thumbs are regular sized. 

It does not do subtle, either. You can run it at lower gain settings, and you can enjoy running it at lower gain settings, but lower gain settings mean that the digital berserker maims away in the background a little less obvious, but it’s still angry. The clipping method is harsh and stays harsh, no matter what you do.
Running it on full blast, feels a bit like you’re trying to watch a movie but someone keeps running a chainsaw through the TV. The picture is a little shaky while the device violently disintegrates and little pieces fly all over the place.

When running the gain that high, I want to say that the note decay is something special – I imagine to hear the following:
The LM308 chip (or rather the identical replacement in mine) is feeding an already distorted signal into the clipping diode. On the decay of the note, one of the two drops out of the equation because the decreasing voltage is not strong enough to cause distortion in both devices. One of them seems to have a digital status (either it’s distorted or it’s not) while the other goes gradually. So there is some spluttering while the device with the on/off nature toggles forth and back while the signal strength is at the threshold.
Might be total bogus, but this is an attempt to put in words what my ears feed me.

Looking at frequency charts, I read that the RAT circuit is as bad as the Tube Screamer in that it emphasizes the higher midrange content and therefore creates the impression that there is a bass cut in play, but I cannot really say that I feel that when playing with the pedal. I can see the benefit of adding a clean blend, especially when you get into the territory of spluttery gain, but that’s more to create a more consistent tone than to add weight. I toyed around a bit with the Rat in the loop of the Broughton Filter Loop pedal, adding a low passed clean signal to mix, but it did not really feel like it’s necessary to ‘rescue’ the lost low frequencies.

It somehow feels a bit like when you’re operating the Distortion knob, that you’re actually twisting a knob that does half of what a gain knob does and half of what a dry/wet blend does. With low settings, there is that gnarly, rabid rodent gnawing at your tone integrity in the background and some clean’ish sound in the foreground and the more you turn it up, the bigger the rat gets and your clean sound fades further in the background.

Running the RAT on high, I can get it into synth territory. It’s not as versatile as the Doom2, of course – it only has three knobs and costs a fraction of the 3leaf pedal, but in a pinch it could serve in that regard.
The idea that stood behind the creation of the RAT was to get even more distortion out of an already distorted tube amp, so my modern approach to throw it into a mostly clean environment and handle most, if not all of the distortion happening is obviously giving it a job it was not constructed for.

Given that, it works surprisingly well. In my band setup, I run the Origin Bassrig SV as my preamp and feeding the rat into that adds a component of pushed amp that kindly masks the angry pocket calculator a bit and gets more into “moose that suffers from throat cancer, but heat is heat”-howling territory.
One thing that quickly becomes apparent: The lows do not feel as massive in the mix as I would have hoped from listening to the pedal while playing solo. I could not really detect that lows get lost while playing with the gain about halfway up and the filter all the way open, so I assume that the added harmonics and the distortion push the upper midrange to a bit more which leads to the impression of a weaker low end. In the mix, the pedal does not cut through with force, but sits rather nicely, even though it’s on the harsher side of hard clipping. Direct comparison with the Way Huge Green Rhino showed what a little EQ in the right position can do – the Rhino has a 100Hz knob that I use for a healthy boost.
Switching off the RAT and kicking in the Rhino mid song brings some of that pants-flapping-earth-shaking thunder that rock and metal bassists usually enjoy quite a lot, and when I did that after I had played a couple of songs with the RAT exclusively so my ears were accustomed to that sound, I felt a huge grin spreading on my face.
The RAT absolutely works for bass, but if you’re looking for something to produce a huge sound with a massive booty, there are several RAT based pedals that offer clean blends and other means of bringing the RAT circuit deeper into the bass players hearts.