NOTE: This is a service. You must provide the pedal for modification
 
The **HGWFx LM Ultra Mod** is a premium professional upgrade for your ProCo RAT pedal, designed to elevate the classic distortion circuit to its full potential while preserving the iconic RAT character that guitarists have loved for decades.
At the heart of this modification is the installation of the legendary **LM308 op-amp** (the "coveted" chip from vintage RATs), which delivers the authentic, gritty, aggressive tone of the original period-correct designs. This op-amp is renowned for its unique slew rate and response that contributes to the RAT's signature biting distortion—smoother yet more dynamic than many modern equivalents.
HGWFx takes it further with a full circuit refresh using high-quality, low-noise components throughout the signal path. This results in noticeably reduced background hiss and improved overall fidelity, giving you clearer articulation, tighter low-end response, and a more refined high-frequency bite without losing any of the RAT's legendary snarl or sustain.
 Key Benefits of the LM Ultra Mod:
- Vintage-accurate LM308 tone — Recaptures the raw, musical aggression of early RAT pedals.
- Lower noise floor — Cleaner operation, especially at higher gain settings or in quiet passages.
- Enhanced clarity and dynamics — Better note definition and touch sensitivity while keeping the thick, saturated distortion intact.
- Three way toggle for three types of clipping. Germanium/Boost/LED
- Professional build quality — Expert soldering and component selection for reliability and longevity.
Whether you're chasing the classic '80s hard rock crunch, modern high-gain leads, or anything in between, the HGWFx LM Ultra Mod transforms your ProCo RAT into a high-fidelity workhorse that sounds bigger, meaner, and more responsive than stock—without straying from what makes the RAT one of the most versatile and enduring dirt pedals ever made.
Perfect for players who want that unmistakable RAT roar, but upgraded for today's demanding rigs. Send in your pedal and let HGWFx bring out its ultra potential!