Let's talk about RATs

RAT2s to be more precise, but I'll touch on others as a reference. The reason I wanted to write this blog about the RAT2 is that it's the most common, easily accessible and most affordable version of this great distortion, and it can get a bad wrap from some of those "vintage is always better" types?

To digress, the RAT was first built in the late 70's by 2 very clever gentleman at Pro Co Sound in Kalamazoo in the US. They wanted to make a superior distortion pedal to what was then currently available and depending on what you like and who you listen to, they either did or didn't.

The details and electronic jibba jabba detailing this circuit is available and plentiful so I won't go too much into it here. If you're that way inclined check out the www and you'll have plenty of rabbit holes to go down. 

After several different versions (mainly cosmetic) of the RAT from '78 to '88 the world was introduced to the RAT2. While the different versions preceding these did have slight electronic changes along with the enclosures, they were all "pretty" similar in parts and tone. That is they all sounded like a RAT.

The "small box" RAT had been introduced 4 years earlier and the RAT2 was simply a progression of this one, which was a successor to the one before that, and so on. The boxes got smaller. The tone stayed the same. 

The first RAT2s were in fact RATs ('84-'88) in a new enclosure with an LED and glow in the dark graphics. The last of the RATs had the PCB with the LED but just didn't have it fitted as Pro Co was using up old stock and getting rid of the previous enclosure. It's not uncommon to find '87/88 RATs with the RAT2 PCB which, are exactly the same circuit, which was the same circuit as the earlier "big box" RAT (version 1 and 2 '79-'83) Sure, there were very minor changes to the circuit over the years with slight changes in resistor and cap values, probably more for parts availability than anything, but the tone was essentially kept intact.

So, having said that an early 80's RAT "should" sound like a late 80's RAT2 right?

Well, yeah, they do and yet pre '88 RATs fetch a premium on the market?

Here's where things get a little..... confusing if you're about to dive into the world of the RAT. The initial RAT2 was the same circuit with an LED and glow in the dark graphics, both of which are pretty cool. It had the same circuit (there have been a few different PCB layouts but the same circuit). The same components and ...... that (in) famous LM308 IC. 

The RAT2 stayed the same from '88 to "about" '95 when Motorola stopped making the LM308 IC and they started going up in price. Pro Co decided to use the much more common OP07 IC which is a direct drop in replacement for the 308. Now here is where I'm going to lose some of you as you throw your arms in the air and storm off in disgust. 

Somewhere between serial number 235390 (pot dates 49th week '95) and 243304 Pro Co started fitting the new IC. On paper it's VERY similar to the 308. I could bore you with slew rates and gain/freq bandwidths between these 2 ICs and several others like the TL/LM/NE/etc series but I won't. The reason I won't is that I own those 2 serial number RAT2s. They are both IDENTICAL except for the IC and pot manufacturer and they both, wait for it, sound identical to me. 

As someone who makes pedals, and makes RATs I'd like to think I know a little about what I'm hearing. I have never claimed to have golden ears or know "good tone" (no such thing) but I can hear 2 pedals side by side and tell if there's any real difference. 


Pro Co kept making this exact pedal (again slight changes to details) until about serial number 259000 when things started to change. Up to this point we have a RAT2 that is the flat top (RAT) enclosure, with the big Pro Co logo on the front, big knobs with a beige/cream coloured PCB (several different layouts) with large (25mm) pots. At this time the RAT2 got the slanted Turbo/You Dirty enclosure and a new green PCB (lost a transistor and got a 3PDT switch) and smaller 16mm pots. These were still made in the US and seem to coincide with the release of the You Dirty RAT in 2004.

The new PCB and pots aren't as nice but are still decent enough and they're still being built into those great heavy folded metal enclosures with good quality jacks and switch. The components are cheaper but values haven't changed and the ones I've worked on are well within specs. 

Then, in 2008 production is moved to China and initially, just like the different US versions, nothing changes, The early Chinese ones have exactly the same PCB and components which could mean Pro Co was importing the loaded PCBs from China and assembling them in the US (to write "made in USA" on them) or they sent all their stock to China to use before moving onto the new version?

The earliest US made green PCB RAT2 I own (serial 269995) has the wires soldered directly to the PCB but by 287619 (2008) these are made in China and have a slightly different layout with IDC plugs connecting most wires to the PCB. 

In the last couple of years the design has changed again and components get cheaper and solder and wiring work has deteriorated again. These new ones can easily be identified as having a standard BOSS style 9V plug and the coloured labels (not just black and white) on the box. 

Now, this is going to be controversial but in my humble opinion the current, brand new Chinese made RAT2 sounds "almost" exactly, and I mean SO close it's almost irrelevant (depending on how you set/use your RAT), to the previous version, which sounds so close to it's predecessor it's ..... well, you get the idea. These new RAT2s are slightly noisier at lower gain settings (disappointing for a newer device) and break up quicker when the DIST is wound up (less clean range on the bottom end of the DIST knob) but like all RATs you can "approximate" any other RAT with pedal/guitar/amp settings.

Pro Co, much like the DOD250 and MXR Dist+ (both of which I LOVE and make clones of) and some others, have, as far as I'm concerned, kept the tone (and look) of the original almost intact to the point where if you're just after a "RAT" I would say buy any RAT. The differences in tone appears to come from component drift/tolerance more than anything and the differences between versions are nowhere near as dramatic as say, a Big Muff or Tubescreamer where 2 side by side can be night and day. Some sound a little "darker" or have slightly less gain/mids/fuzz at a certain setting but these can be dialed in/out easily. Some, and not any version in particular have slightly less output which appears to be component tolerances more than anything.

If someones insisting you need an LM308 in your RAT then they're trying to sell you a RAT with an LM308 in it, or an LM308. I'm not saying there's no difference, but most of that difference can be dialed out (or in) with your guitar and/or amp and what's left isn't worth the extra $1000 (or even $2000) you'll spend on it. I know people who prefer the OP07 and I have one friend who has vintage RATs and uses the Chinese re-issue on his board 'cause HE thinks it sounds better with his set up.

I make and sell my Toecutter series that blatantly has "LM308 loaded" on the front but that's because I have plenty of NOS 308s to use up and this is the only pedal I use them in. The price would be the same if I was using something else like the NE5534, or OP07, which I would happily use in their stead. I have tried every Op Amp that drops in (with and without comp capacitor) to my Toecutter circuit and the difference is ...... negligible at best.

Like all things in the guitar/music/collector world if you can afford the stuff with "mojo" (no such thing) and it makes you feel good, buy it. But if you're struggling and just want to write songs and play music and have fun, you don't need that vintage this or that rare that. There's plenty of modern/current takes on stuff that don't cost the earth and are nearly, or just as good at the job at hand and apart from the build quality of the last few years of the RAT (and I must admit I haven't had to fix any yet which may mean they're reliable or they are just too new to be breaking yet?) I would happily use a current RAT any day. 

Below is a list of some of the RATs I own with serial numbers/pot dates/details that may help people decide on what to buy. The serial number does not have a date code. Note that Turbo/You Dirty/Solo etc serial numbers are not sequential within RAT #s. 16mm pots do not have date marks. PCB colours/designs varied in layout.

RAT 032077 Flat box USA 8546 Beige PCB LM308 1 FET Big knobs 

RAT2 N/A Flat box USA 9213 Beige PCB no markings 4 diodes LM308 Big knobs WOODCUTTER

TURBO 204694 Slant box USA 9515 Beige PCB no markings LM308 Big knobs 
TURBO 102876 Slant box USA 9834 Beige PCB LM308 Big knobs

VINTAGE 156605 Flat box USA 9125 Beige RAT RE-ISSUE PCB LM308 1 FET

RAT2 213009 Flat box USA 9610 white PCB LM308 2 FET Big knobs

RAT2 235390 Flat box USA 9549 Beige LM308 2 FET Big knobs
RAT2 243304 Flat box USA 3977 0031 Beige PCB OP07 2 FET Big knobs
RAT2 243658 Flat box USA 3977 0031 Beige PCB OP07 2 FET Big knobs
RAT2 247130 Flat box USA 3977 0114 Beige PCB OP07 2 FET Big knobs
RAT2 247507 Flat box USA 3977 0115 Beige PCB OP07 2 FET Big knobs
RAT2 254180 Flat box USA 3997 0223 Beige PCB OP07 2 FET Big knobs 2003

RAT2 259782 Slant box USA N/A Green PCB OP07 1 FET Small pots

TURBO 112315 Slant box USA N/A Beige PCB V2 OP07 1 FET Small pots

YOU DIRTY N/A Slant box USA N/A Green PCB OP07 1 FET Small pots 
RAT2 269995 Slant box USA N/A Green V3 OP07 1 FET Small pots

SOLO 115188 Slant box USA N/A Green OP07 1 FET 4 small pots

RAT2 287619 Slant box China N/A Green IDC plugs OP07 1 FET Small pots
RAT2 293864 Slant box China N/A Green IDC plugs OP07 1 FET Small pots
RAT2 303369 Slant box China N/A Green IDC plugs OP07 1 FET Small pots
RAT2 303725 Slant box China N/A Green IDC plugs OP07 1 FET Small pots
RAT2 306102 Slant box China N/A Green V4 OP07 1 FET Small pots
RAT2 323540 Slant box China N/A Green V4 OP07 1 FET Small pots
RAT2 324745 Slant box China N/A Green V4 OP07 1 FET Small pots

RAT2 42000130 Slant box China Brown PCB OP07 1 FET Small pots 


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