Stomp Under Foot Skinner Box & Sonic Black

More Than Just Dirt: Diving into the Stomp Under Foot Skinner Box and Sonic Black

Today, we’re stepping away from the familiar Big Muff sounds (though we love them dearly!) and venturing into the realm of truly versatile and often misunderstood dirt pedals. We’re talking about the iconic RAT circuit and Stomp Under Foot’s masterful takes on it: the Skinner Box and the Sonic Black.

While “fuzz” often conjures images of thick, sustained saturation, the RAT circuit offers something distinctly different – a gritty, articulate, and often aggressive distortion that can also clean up beautifully. Let’s trace its lineage and then unpack how SUF brings its magic to these crucial tones.

The Rise of the RAT: A Happy Accident That Defined a Generation

The story of the ProCo RAT pedal is one of accidental genius. Developed in the rat-infested basement (hence the name!) of the ProCo factory in Kalamazoo, Michigan, in 1978, by engineers Scott Burnham and Steve Kiraly, it was initially a custom-order product. Legend has it that Burnham stumbled upon its unique sound when he mistakenly used the wrong resistor value while biasing an operational amplifier (the LM308 op-amp, which became a key component). This “happy accident” created a much higher amount of gain with harmonically rich overtones – a distinct “op-amp distortion” that was novel at the time.

The original “Bud Box” RATs were handmade in limited numbers before mass production began in 1979. Its unique blend of distortion and fuzz-like qualities, along with its highly interactive “Filter” (tone) control, made it incredibly versatile.

Notable Players & Their RAT Sounds:

The RAT quickly became a secret weapon for countless guitarists across genres:

• Kurt Cobain (Nirvana): While famous for Boss DS-1s, the RAT was notably used on “Territorial Pissings” from Nevermind for its trashy, aggressive punk sound, often plugged directly into the mixing board alongside an amp.
• James Hetfield (Metallica): Early Metallica albums like Kill ‘Em All were loaded with RAT noise, contributing to the famous tones of early thrash metal when combined with his Marshall amps.
• Jeff Beck: A long-time user, Beck famously employed the RAT live from the mid-80s up until 1999 and prominently on his Guitar Shop album, showcasing its articulate yet raw character.
• Dave Grohl (Foo Fighters): Rumor has it the Foo Fighters’ debut album was heavily loaded with RAT sounds, contributing to his hard rock vision.
• Jonny Buckland (Coldplay): Used on tracks like “Violet Hill” for its distinct gritty texture.
• Graham Coxon (Blur): The RAT is rumored to be a key ingredient in the huge fuzzy sound of “Song 2” and other tracks on Blur’s self-titled album.
• Nuno Bettencourt (Extreme): Known for loving a gritty distortion, the RAT was his go-to pedal for a long time.
• David Gilmour (Pink Floyd): While known for Big Muffs, Gilmour wasn’t afraid to crank the gain, and the RAT did make appearances in his rig for specific high-gain applications.
• Andy Summers (The Police), Joe Walsh, Robert Fripp, Joe Perry, and Michael Stipe (R.E.M.): also notably incorporated the RAT into their tones, demonstrating its incredible versatility across different styles.

The RAT’s unique “Filter” control rolls off high frequencies as you turn it clockwise, which is counter-intuitive for some but incredibly effective for shaping the bite and smoothness of the distortion.

Mastering the RAT with the Skinner Box and Sonic Black

Matt Pasquerella at Stomp Under Foot, known for his obsessive dedication to vintage circuits, has poured his expertise into two incredible takes on the RAT: the Skinner Box and the Sonic Black. Both are handmade in the USA with meticulous attention to detail and often feature rare, original components, offering distinct flavors of this legendary circuit.

The Skinner Box: The Original “Bud Box” RAT Reborn

The Stomp Under Foot Skinner Box is Matt’s faithful recreation of the highly coveted “Bud Box” RAT – the very earliest, low-production version from 1978. What makes this special? It uses the now-obsolete metal can version of the LM308 op-amp, which many connoisseurs believe contributes to a warmer, smoother, and more organic tone than later plastic-housed versions.

• Tone Profile: The Skinner Box delivers a classic, high-gain distortion that can go from a thick, gritty overdrive (around 12 o’clock on the gain) to a monstrous, singing distortion at full tilt. It retains remarkable clarity and punch, even at higher gain settings, allowing individual notes to cut through.
• Versatility: Don’t let the “distortion” label fool you. By rolling back the gain, the Skinner Box can provide a creamy, rich overdrive that pushes your amp beautifully. The filter control is highly interactive, allowing you to fine-tune the treble content from searing to dark and brooding.
• Feel: Due to the specific components and meticulous build, the Skinner Box has an incredibly responsive feel. It cleans up well with your guitar’s volume knob and reacts dynamically to your picking attack, just like those original units.

If you’re after that iconic, articulate, yet aggressive RAT tone that defined so much of the 80s and 90s alternative, metal, and punk scenes, the Skinner Box is an absolute must-try. It’s the sound of Kurt Cobain’s trashy aggression and Jeff Beck’s articulate bite, bottled and ready to rip.

The Sonic Black: A Warmer, Refined RAT Experience

While the Skinner Box aims for faithful “Bud Box” accuracy, the Stomp Under Foot Sonic Black offers a slightly different, warmer take on a RAT-based circuit. This pedal is designed to tame some of the extreme high-end often associated with RATs, offering a smoother, rounder character, especially on higher strings and leads.

• Tone Profile: The Sonic Black features a slightly warmer, more refined tone. The high side of the filter control has been modified to round off some of the treble, making it less piercing without sacrificing clarity. This results in a thicker, more sustained lead tone that feels less harsh than some other RAT variants.
• Gain & Clarity: At full gain, the Sonic Black provides a punchy distortion that still holds its clarity, allowing each string to be heard even under heavy saturation. As you roll the gain down, it transitions into a great, snappy, and spanky overdrive, retaining warmth and body.
• Ideal For: If you love the core character of a RAT but find some versions a bit too bright or aggressive for your setup, or if you prefer a smoother, more liquid distortion for leads, the Sonic Black could be your ideal solution. It’s fantastic for pushing an amp into a melodic, sustained overdrive or for dialing in a full, rich distortion that doesn’t get lost in the mix.

Finding Your RAT Flavor

Both the Skinner Box and Sonic Black exemplify Stomp Under Foot’s dedication to sonic excellence. They’re not just clones; they’re meticulously crafted instruments designed to deliver the nuanced, sought-after tones of legendary circuits.

• For the purist chasing classic aggression: The Skinner Box is your direct line to the original “Bud Box” RAT magic, complete with the revered metal can LM308.
• For a warmer, smoother, yet still powerful RAT experience: The Sonic Black offers a refined take that tames the high-end for more liquid leads and a thicker overall tone.

The best way to decide is to hear them for yourself! Come on down to Tone Tailors and let us plug you into these incredible pedals. Explore the dynamic range, the articulate crunch, and the singing sustain that has made the RAT circuit legendary for decades. Your next favorite dirt pedal might just be waiting.