
RODENT Distortion
Based on
Mercuriall calls Rodent its take on the ProCo RAT circuit (mercuriall.com (opens in new tab)).
- Type
- Pedal
- Era
- 1980s
About this block
Raw, Versatile Classic Distortion
Rodent is Mercuriall Audio's take on the ProCo RAT distortion circuit, with the aggressive clipping, focused midrange, and wide gain range the original is known for — from gritty overdrive through thick distortion to near-fuzz saturation.
The characteristic Filter control shapes the upper end from cutting and immediate to dark and smooth, while the circuit's natural compression adds sustain without erasing pick attack. On bass, this is one of the few classic dirt circuits that works without a parallel clean blend: the focused midrange keeps a distorted bass part audible in a dense mix instead of burying it under the guitars.
Rodent is modeled with Mercuriall's State-Spice analog circuit simulation technology, including the slew-limited op-amp behavior that gives the original its edge. Its input level is calibrated to Anagram's input sensitivity and its output to Mercuriall's amplifier models, preserving real-world instrument-to-pedal-to-amp gain staging whether you use it as a distortion or as a boost.
Key Features
- Distortion model inspired by the ProCo RAT circuit
- Wide gain range from gritty overdrive to heavy distortion
- Characteristic RAT-style Filter response
- Focused midrange with strong harmonic content
- Slew-limited op-amp character of the original topology
- State-Spice analog circuit simulation of the pedal topology
- Input calibrated to Anagram sensitivity; output calibrated to Mercuriall amp models
Legal Disclaimer
ProCo and RAT are trademarks or registered trademarks of their respective owners. Mercuriall Audio Rodent was developed by Mercuriall Audio using its own modeling techniques. The respective trademark owners have not endorsed or sponsored Mercuriall Audio Rodent in any manner, nor licensed any intellectual property for use in this product.
Details
- Vendor
- Mercuriall Audio
- Category
- Overdrive & Distortion
- Type
- Fuzz
- Price
- Free
- Tags
- distortion, overdrive & distortion
- Listed
- Updated

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