Electro-Harmonix Micro Q-Tron Envelope Filter Pedal

Electro-Harmonix Micro Q-Tron: The Classic Auto-Wah in a Compact Box

The Electro-Harmonix Micro Q-Tron is a compact envelope-controlled filter, an auto-wah pedal that packs the expressive Q-Tron voice into a pedalboard-friendly enclosure. The loudness of your playing sweeps a resonant filter, producing funky, vocal, hands-free wah effects without a treadle. It keeps the musical heart of the larger Q-Tron while saving precious board space and running on a simple 9-volt battery. For the funk and R&B player who wants that quacky filter movement but has no room for a big box, this is the answer. Plug in, dig into a groove, and every note breathes.

How the Envelope Sweeps the Filter

An envelope filter tracks the envelope, the rising and falling volume, of your signal and uses it to move a resonant filter's cutoff frequency. Pick harder and the filter sweeps further up; let the note decay and it falls back, creating the vowel-like wah sound automatically. The Drive control sets how sensitive that sweep is to your picking dynamics, so your right hand effectively becomes the expression pedal. This is why an envelope filter feels so responsive and alive compared with a fixed filter. A light touch yields gentle motion, and a hard attack snaps the filter wide open.

Low, Band, and High Pass Modes

The Mode switch chooses which type of filter the envelope drives, and each gives a different character. Low Pass produces the deep, round, bass-heavy quack most associated with classic funk. Band Pass narrows the response to a vocal, nasal midrange that cuts through a band, while High Pass gives brighter, thinner, more synth-like sweeps. Being able to choose the filter shape lets the Micro Q-Tron move from subtle wah to pronounced, expressive effects. One small pedal covers a surprising range of filter voices.

Q and Drive: From Subtle to Funky

The Q control sets how narrow and resonant the filter peak is, shaping how vocal or dramatic each sweep sounds. A low Q gives a smooth, gentle motion, while a high Q produces the sharp, quacky peak that defines funk guitar and bass. The Drive control works alongside it to set the pedal's sensitivity to your input level and dynamics. Together they let you dial anything from a light shimmer on clean chords to an aggressive, rubbery auto-wah. These two knobs are where the Micro Q-Tron's personality lives.

Voiced for Guitar, Bass, Keys, and Horn

The Micro Q-Tron is equally effective on guitar, bass, keyboards, and horns, because its controls adapt to a wide range of input levels and frequencies. Bassists love it for the deep, funky filter that drives disco and R&B lines, while guitarists use it for quacky rhythm and lead work. Keyboard players run electric pianos and synths through it for swept, resonant textures. That versatility makes it a useful studio tool as well as a stage pedal. Any dynamic signal can drive the envelope.

Compact Design, True Bypass, and Who It Is For

The Micro Q-Tron fits the classic Q-Tron voice into a small enclosure, so it claims minimal pedalboard space while still offering full Volume, Q, Drive, and Mode control. True-bypass switching passes your dry signal untouched when the effect is off, preserving your tone in a chain. It runs on a 9-volt battery or an optional 9.6-volt DC power supply, making it easy to fit into any rig. It suits the funk, R&B, and fusion player who wants expressive filter movement in a board-friendly size. If the full-size Q-Trons are too large for your setup, the Micro delivers the same soul in less space.