La Rata (ProCo RAT)

geoffrey

Well-known member
Build Rating
4.00 star(s)
Ah, I remember when I first began this hobby like yesterday. That's because it pretty much was. Hard to believe that it was only just this past November when I built my first pedal. And although I can't keep the production line going as fast as @MichaelW, I've built a decent number of pedals over the last few months. Enough to where (although I am not) I feel like a seasoned veteran at times. A lot of this has to do with the help of this community; I tip my hat to all of you.

Anyway, back in the "early days" when I didn't know the difference between any PCB providers, I was taken in by a Black Friday sale of a certain European PCB company. The deals were ridiculous and I thought, "Holy S***! Look at all these dope boards! Time to load up!" So, I ordered like 10 thinking I was about to have a board full of Grade A tone and filth. However, when I later checked our forum here for any build reports or posts on any of these, my dreams were crushed. The consensus among the PedalPCB faithful was not good, and, feeling foolish for not checking our community before going wild on Black Friday, I put these boards at the bottom of my pile.

Now that I'm on a mission to compare RAT circuits for fun, I remembered the La Rata board in my pile and thought now was the time to bite the bullet and see for myself what Guitar PCB Mania was all about. I wasn't enthused when looking at it after I pulled it out. Having been spoiled by the glory that is a PPCB build, I felt like I was about to enter the dark ages...like going from a Mach 4 back to a single blade. Certainly, I thought to myself, no matter how clean this build will be, this thing isn't going to work. It'll be a waste of a Saturday morning, but I have to know.

Well, what I now know is that, to my surprise, this is a legit RAT that sounds fantastic. Like others out there, this board allows you to build any of 4 different variants and add a second (or third?) clipping option for a 2-in-1. I went with the classic variant with 1N914's and Turbo Rat LEDs for my second clipping option. I was confused (and still am) if there is a 3rd clipping option using D6 (which I put an LED in) because the build requires an on-off-on switch, but with the third switch setting sounding the same as middle (Turbo Rat), I was at a loss. This was unclear in the build document.

In addition to the 3 traditional knobs, I added a 4th "Sweep" knob, a classic mod that works well. There is an additional "Softness" control (meant to interact with the clipping) but I opted for the trimmer instead of the external because others in our forum here stated it didn't do much (which is true). However, when using a center punch prior to drilling, I forgot I had made this choice and began punching where this 5th pot would be. Hence the decal, which I had made for fun when I first started building. Luckily, the colors matched. I find it amusing for now (Rat's are indeed pure filth, are they not?), but will take it off when I tire of it; nothing wrong with displaying some battle wounds.

I compared the La Rata to my Fuzzdog Rodent (I gave my Muroidea to a friend and am in the process of replacing it), and it held its own. Is this comparable to a PPCB build? Heck no. But I'm happy to give it 4 stars. Isn't near to the user-friendly design of a PPCB (or even a Fuzzdog) board, and I'm still befuddled by the whole 3-way switch clipping thing, but this is a darn good rat. So that's 1 for 1 one with Guitar PCB Mania builds for me. Granted it's just one, but gotta give credit where credit is due. I wouldn't pick this over the previous boards I mentioned, but if you come across one or they have a big sale, I'd have no problem recommending it.

Thanks for reading. I know my build reports tend to be long and basic, but I like sharing them. Next Rat for me is the Effects Layouts version. If there are others you all recommend that I check out, let me know!

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The "La Rata" is one of the "checked out as good" PCBGM boards, all safe there! Great job!
 
The "La Rata" is one of the "checked out as good" PCBGM boards, all safe there! Great job!
Thanks! I want to try their Lightspeed (Einstein Constant Overdrive) and ODR-1 (Proton Green) boards. Anyone know if these are worth it?
 
Good lookin' build, whatever the PCB inside.


Not sure if this is too basic or if it will help you understand diode-clipping switches...

CLIPPING DPDT 2023-04-01.png


The green LEDs have the highest Forward Voltage ("Fv" on DATASHEETS), so they go in the middle "OFF" position. Then put whatever lower Fv diodes you want on either side. Don't populate the PCB's diodes, choose one diode's set of holes and run the wires from the switch to them.

I've shown 3-diodes in the UP toggle position (which in the diagram is the bottom of the switch), giving asymmetrical clipping if the combined Fv of D6 and D7 are not greater than the Fv of the LED. If the combined Fv is NOT greater, then the LED for that direction wins and the two diodes in series may as well not be there at all — the good news is the clipping will still be asymmetrical given the different voltages of the outer diode (1N914, 1v, for example ) vs the Green LED's 2v. So if you have two 1N914s in series, that's 2v — same as the Green LED. If it's two Schottky diodes in series (0.3Fv each for a total of 0.6Fv) then the Green LED is effectively ignored and you'll have the desired asymmetrical clipping without the Green LED getting in the way. There are plenty of DATASHEETS, diagrams and info online that give a good rough guesstimation of Fv for various diodes commonly used to clip signal in effects).

In my diagram, basically the signal always goes to the highest Fv of the bridged DPDT's centre pins, unless an easier path is found (flipping the toggle UP or DOWN out of the middle "OFF" position.
This is true of hard-clipping (ie to ground) as in a Rat, or soft-clipping (ie in an op-amp's feedback loop) as in a Tube-Screamer.




So if a PCB's build-guide specs an on-on and provides two different clipping options, I'll often [EDIT: USE an ON-OFF-ON and] stick in diodes of my choice and solder LEDs right across pins 2 and 5 of the onboard-soldered [ON-OFF-ON] switch...
 
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Good lookin' build, whatever the PCB inside.


Not sure if this is too basic or if it will help you understand diode-clipping switches...

View attachment 45202


The green LEDs have the highest Forward Voltage ("Fv" on DATASHEETS), so they go in the middle "OFF" position. Then put whatever lower Fv diodes you want on either side. Don't populate the PCB's diodes, choose one diode's set of holes and run the wires from the switch to them.

I've shown 3-diodes in the UP toggle position (which in the diagram is the bottom of the switch), giving asymmetrical clipping if the combined Fv of D6 and D7 are not greater than the Fv of the LED. If the combined Fv is NOT greater, then the LED for that direction wins and the two diodes in series may as well not be there at all — the good news is the clipping will still be asymmetrical given the different voltages of the outer diode (1N914, 1v, for example ) vs the Green LED's 2v. So if you have two 1N914s in series, that's 2v — same as the Green LED. If it's two Schottky diodes in series (0.3Fv each for a total of 0.6Fv) then the Green LED is effectively ignored and you'll have the desired asymmetrical clipping without the Green LED getting in the way. There are plenty of DATASHEETS, diagrams and info online that give a good rough guesstimation of Fv for various diodes commonly used to clip signal in effects).

In my diagram, basically the signal always goes to the highest Fv of the bridged DPDT's centre pins, unless an easier path is found (flipping the toggle UP or DOWN out of the middle "OFF" position.
This is true of hard-clipping (ie to ground) as in a Rat, or soft-clipping (ie in an op-amp's feedback loop) as in a Tube-Screamer.




So if a PCB's build-guide specs an on-on and provides two different clipping options, I'll often stick in diodes of my choice and solder LEDs right across pins 2 and 5 of the onboard-soldered switch...
This is a great diagram and definitely not too basic for me. Thanks! I’ll try a build like this

I’m still confused why this build called for an on-off-on switch when there only ended up being 2 clipping options. But whatever I guess, it sounds good lol.
 
This is a great diagram and definitely not too basic for me. Thanks! I’ll try a build like this

I’m still confused why this build called for an on-off-on switch when there only ended up being 2 clipping options. But whatever I guess, it sounds good lol.

Your build's Middle position has a "diode lift", ie you can get the clipping of just the op-amp.
Depending on the circuit, it could be Transistor-clipping, too, ie when the signal "hits the rails" ie exceeds what the transistors or op-amp are/is capable of handling and clip.

A lot of people like how just the LM308 in a Rat clips on its own, and it is a pretty big part of "The Rat Sound".
I imagine the other Rat chip, the OP07DP, sounds about the same when clipped on its own. Might be worth doing some chip-rolling and see...
 
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Your build's Middle position has a "diode lift", ie you can get the clipping of just the your op-amp.
Depending on the circuit, it could be Transistor-clipping, too, ie when the signal "hits the rails" ie exceeds what the transistors or op-amp are/is capable of handling and clip.

A lot of people like how just the LM308 in a Rat clips on its own, and it is a pretty big part of "The Rat Sound".
I imagine the other Rat chip, the OP07DP, sounds about the same when clipped on its own. Might be worth doing some chip-rolling and see...
that makes total sense. Thanks for taking the time to help!
 
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