Crotronics Dr Wub Stereo Harmonic Tremolo Pedal

The Dr Wub is a stereo harmonic tremolo designed to transform simple amplitude modulation into a swirling, panoramic tone engine. This pedal features independent per-channel tremolo modes, eight selectable waveforms (plus a hidden second bank), expanded harmonic depth, and  tap tempo — all through a fully analog signal path running at 18 volts for increased headroom — Dr Wub is an effect you’ll have a hard time turning off.

Features

Drive Control (+17 dB Clean Boost)

Push your amp, lift your signal, or compensate for depth-heavy modulation:

• Up to +17 dB of boost

• Can be used as a preamp at minimum depth settings to push proceeding devices into overdrive

• Great for compensating for perceived volume loss

Dual-Mode Tremolo Per Channel

Each side of Dr Wub can independently run in standard tremolo (amplitude modulation) or harmonic tremolo (split high/low modulation).

• Left and right operate separately — mix and match modes for layered movement

• Pan between channels with both trems set to standard mode

• Dial in classic bias-like throbs, smooth optical pulses, or swirling harmonic warmth

8 Main LFO Waveforms

Choose from eight shapes to sculpt your modulation:

• Sawtooth

• Reverse Sawtooth

• Square

• Triangle

• Sine

• Sweep

• Lumps

• Random

Secret 2nd bank of LFO Patterns can be accessed by way of an internal DIP Switch

• Ramp +Oct

• Quad Ramp

• Quad Pulse

• Tri Step

• Sine +Oct

• Sine +3rd

• Sine +4th

• Random Slopes

Enhanced Harmonic Depth 

Dr Wub’s harmonic tremolo mode goes deeper than vintage circuits. The increased depth of its high and low pass filters impart an almost phaser-like aspect to the sound.

• Warm vintage wobble or intensely submerged psychedelic warping

Stereo Harmonic Split Output

When both Tremolo channels are set to Harmonic mode and you select Split output:

• Trem 1 (Left Channel) = high-pass tremolo

• Trem 2 (Right Channel) = low-pass tremolo

This creates a unique stereo image where frequencies dance across the soundfield — a rotating sensation that feels alive and immersive, like standing between two mismatched vintage amps being alternately modulated.

Optional Right-Channel Phase Flip

Flip the audio phase of the right channel to create additional phase interaction between the two sides.

• Enhances stereo width and spatial movement

• Produces deeply hypnotic patterns when paired with the complex LFO shapes

• Increases the three dimensional sense of modulation, especially in harmonic mode

This simple switch dramatically expands the dimensionality and psychoacoustic behavior of the effect.

The Dr Wub transforms tremolo into a stereo aural landscape — from vintage wobble to psychedelic swirl.