ProCo RAT vs Electro-Harmonix Big Muff Pi
ProCo RAT wins for the most versatile guitar-player-friendly distortion — its wide gain range produces convincing overdrive, distortion, and fuzz-like characters from a single pedal. Big Muff wins for the specific, iconic fuzz sustain and harmonic character that the RAT cannot fully replicate — the Muff's long sustain and harmonic density are a different thing entirely.
ProCo RAT
Harder-clipping distortion with a unique Filter control that runs backwards (clockwise = darker). Warmer and more compressed than the DS-1, with more amp-like harmonic content across a wider gain range.
Blues rock, alternative, post-punk, hard rock — harmonically rich distortion with more low-gain versatility
Electro-Harmonix Big Muff Pi
Infinite sustain fuzz. The scooped mid character is immediately recognisable across rock, grunge, shoegaze, and stoner rock.
Rock, grunge, shoegaze, stoner rock — any genre needing walls of fuzz
Tone Character
ProCo RAT
- ✓ Versatile Filter control
- ✓ Warmer character than DS-1
- ✓ Works as overdrive at low gain
- ✓ Classic studio pedal on thousands of records
- ✗ Filter control is counter-intuitive (inverted)
- ✗ Doesn't clean up with guitar volume
- ✗ Noisy at maximum gain
Electro-Harmonix Big Muff Pi
- ✓ Massive sustain
- ✓ Iconic character
- ✓ Affordable
- ✓ Works at high gain
- ✗ Scooped mids cut through poorly in band context
- ✗ Volume drop at mid settings
- ✗ Less dynamic than germanium fuzz
When To Choose Each
Versatile rock distortion across styles from blues-rock to alternative to metal — the RAT's LM308 op-amp produces a unique harmonic character at all gain levels.
Shoegaze, grunge, heavy alternative, psychedelic fuzz — the thick, sustained Muff character that defines an era and a genre.
Final Verdict — ProCo RAT vs Electro-Harmonix Big Muff Pi
Best for beginners
ProCo RAT
ProCo RAT scores higher on versatility (62/100) and lower on gain (68/100) — a more forgiving starting point than Electro-Harmonix Big Muff Pi.
Best for metal tones
Electro-Harmonix Big Muff Pi
Electro-Harmonix Big Muff Pi leads on gain (72/100) and bass response (60/100) — the two tonal pillars of metal playing.
Best value
ProCo RAT
At £79 vs £79, ProCo RAT delivers 0% cost savings. The tonal trade-off is meaningful.
Specification Summary
| ProCo RAT | Electro-Harmonix Big Muff Pi | |
|---|---|---|
| Price | £79 | £79 |
| Category | Distortion | Fuzz |
| Gain | 68/100 | 72/100 |
| Warmth | 55/100 | 62/100 |
| Treble | 52/100 | 45/100 |
| Bass | 45/100 | 60/100 |
| Versatility | 62/100 | 48/100 |
| Best for | Blues rock, alternative, post-punk, hard rock | Rock, grunge, shoegaze, stoner rock |
Not sure which to choose?
Use the Rig Builder — tell it your genre, budget and playing style and it will recommend the right gear for you.
Build My Rig →