The Mad Professor Evolution Orange Underdrive is an underdrive pedal from Mad Professor that flips the usual overdrive idea on its head. Instead of overdriving your clean tone, it gets cleaner tones from an overdriven tone: you set your amp for its driven sound, then step on the pedal to pull the signal down so the amp cleans up1.
The circuit works by lowering the midrange, because that is where the overdrive mostly is1. Where a typical overdrive pedal adds gain in front of a clean amp, the Underdrive subtracts level and midrange content in front of an amp that is already cooking.
How it works and how it is controlled
The pedal has four controls. The volume control sets exactly how much the signal to your amp is reduced, which is how you clean up a dirty sound2. The midrange knob shapes the cleaner tone's midrange, the part of the sound where the overdrive largely comes from, while the bass and treble knobs get that cleaner tone sitting just right2. Mad Professor's own description of the process is to set the volume for the amount of clean-up you want, then set the bass and treble to tailor your clean tone1.
| Control | What it does |
|---|---|
| Volume | Sets exactly how much the signal to your amp is reduced2 |
| Midrange | Shapes the cleaner tone's midrange, where the overdrive largely comes from2 |
| Bass | Shapes the cleaner tone's low end2 |
| Treble | Shapes the cleaner tone's high end2 |
What amps it suits
Mad Professor says the Evolution Orange Underdrive works really well with vintage single channel amps that sound great when you push them to overdrive1. That is the practical case for the pedal: a single channel amp has no clean channel to switch to, so instead of turning the amp down, you step on the Underdrive and get your clean tone from the same settings.
How it compares with the HomeBrew Detox EQ
The pedal is not alone in this job. MusicRadar's review notes that the HomeBrew Electronics Detox EQ, a Paul Gilbert signature pedal, does a similar job2. Both take the approach of cutting the frequencies that push an amp into overdrive rather than adding gain to a clean signal.
What reviewers said
MusicRadar's review was positive on both counts that matter here. Under reasons to buy it lists "Instant clean tone. Easy to use." and under reasons to avoid, simply "Very few."2 The review's overall verdict captures the appeal of the concept:
"There's a certain simplicity to stepping on a pedal for a cleaner sound. Genius."
Videos
Mad Professor Amplification
Mad Professor Amplification
Mad Professor Amplification
Questions
What is an underdrive pedal?
An underdrive does the opposite of an overdrive. Instead of pushing a clean amp into distortion, it reduces the signal going into an amp that is already overdriven, so the amp cleans up. The Evolution Orange Underdrive lowers the midrange, where most of the overdrive lives, and gives you bass, midrange, treble and volume controls to shape the cleaner tone.
Is the Evolution Orange Underdrive like the HomeBrew Detox EQ?
They do a similar job. MusicRadar's review notes that the HomeBrew Electronics Detox EQ, a Paul Gilbert signature pedal, also works to get cleaner tones from a driven amp. Both pedals cut the frequencies that push an amp into overdrive rather than adding gain.
What amps does the Evolution Orange Underdrive work with?
Mad Professor says it works really well with vintage single channel amps that sound great when you push them to overdrive. With a single channel amp you set the amp for your driven sound, then step on the pedal to get a clean tone from the same channel.
Sources (2)
- Mad Professor Launches New Guitar Gear 2023, Premier Guitar, 2015-01-30
- Mad Professor Evolution Orange Underdrive review, MusicRadar, 2015-11-22
Paul Gilbert
