Looking for a pedal that captures the raw, wild sound of the Seattle music scene? The JPTR FX Warlow is a premium-quality op-amp fuzz painstakingly rebuilt to deliver a massive, wide sound with terrifying levels of gain and volume.
If you are chasing that screaming, sustaining tone famously wielded by Billy Corgan, look no further. Chris and the crew at JPTR FX over in Germany build precision-crafted, high-grade noise equipment, and the Warlow is an absolute beast. Hand-built in small batches, it takes the DNA of a vintage fuzz and mutates it into something incredibly versatile.
Here is why the JPTR FX Warlow is our Pedal of the Week.
Under the Hood: More Than a Clone
The Warlow’s backstory is what makes it truly special. It was painstakingly reverse-engineered from a vintage Big Muff boasting the exact same release date as the Smashing Pumpkins’ Siamese Dream album. But JPTR FX didn’t just stop at cloning it; they hot-rodded the circuit:
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Op-Amp Driven: Instead of traditional transistors driving the signal, the Warlow utilizes op-amps, providing a distinct, aggressive character.
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LED Clipping: Swapping out standard diodes for LEDs in the clipping stages results in massive headroom, a pronounced mid-scoop, incredibly fat lows, and a bright, sizzling top end.
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Amp-Pushing Volume: With the volume rolled up, the Warlow has enough output to severely punish the front end of your tube amp.
The Secret Weapon: The Tone Stack Toggle
What truly sets the Warlow apart from the sea of Muff-inspired pedals is its genius filter section. A dedicated toggle switch allows you to flip between three entirely different tone stacks:
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Classic Muff: Delivers that iconic, scooped-mid wall of sound.
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RAT Filter: Brings in the biting, mid-forward attack of a ProCo RAT.
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Muff/RAT Hybrid: The middle position blends the best of both worlds—our absolute favorite setting for punchy rhythm parts that need to cut through a dense mix.
New Feature: The Gate Switch
JPTR FX recently updated the Warlow to include a brand-new Gate switch. Flipping this on chokes the circuit, transforming the lush sustain into an ugly, snarling, sputtering gated fuzz perfect for nasty, velcro-like textures.
Suggested Settings
The Warlow is surprisingly versatile. While its true magic shines with the distortion completely maxed out, the highly responsive Tone knob and hybrid toggle mean there are plenty of usable sounds hiding throughout the sweep.
I’m a huge fan of Big Muff circuits and have loved the ProCo Rat since I got my first one in the 1980s, so this pedal is right up my street. It isn’t hard to dial in, but it can get pretty raucous and loud fast!
| Setting Name | Volume | Tone | Distortion | Toggle Position | Gate Switch |
| The ’93 Pumpkin Smash | 2 o’clock | 12 o’clock | Maxed | Classic Muff | Off |
| Seattle Hybrid Rhythm | 1 o’clock | 1 o’clock | 3 o’clock | Muff/RAT Hybrid | Off |
| Sputtering Velcro | 3 o’clock | 2 o’clock | Maxed | RAT Filter | On |
| Low-Gain Grind | Maxed | 10 o’clock | 9 o’clock | Muff/RAT Hybrid | Off |
Frequently Asked Questions (FAQ)
Is the Warlow just another Big Muff clone?
Not at all. While its roots are in a very specific vintage op-amp Muff, the LED clipping, massive output volume, customizable tone stack, and gated fuzz option make it a totally different beast capable of much more than standard cloning.
Does it only do 90s Grunge?
While it screams 90s alternative rock, the Warlow is incredibly dynamic. Thanks to the wide sweep of the Tone knob and the three-way filter switch, it handles everything from doom metal sludge to surprisingly usable low-gain overdrive textures.
Where is it made?
Every Warlow is hand-built in small batches by Chris and the team at JPTR FX in Germany, ensuring premium build quality and precision craftsmanship.
Our Verdict
The JPTR FX Warlow is an absolute triumph for fuzz lovers. It takes the familiar, nostalgic fuzz tones of the early 90s and injects them with modern versatility, bone-rattling low end, and soaring highs. The addition of the Muff/RAT hybrid filter and the snarling Gate switch elevate it from a simple tribute pedal into an essential, gig-ready fuzz monstrosity.
If you want to stand out from the crowd and completely take over a mix, the Warlow is a staple that belongs on your pedalboard.
It is perfect for grunge, doom, shoegaze, and more. Plus, it works equally well on guitar and bass (it also loves my Bass VI).
Chris makes small batches of these and often has limited-run colorways, if you like that sort of thing. They all sound brutal and are perfect for setting the world on fire.
Score 5/5 (for fans of Big Muffs and the Pumpkins)
More Information
#JPTR FX #Warlow #Pedal of the Week
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