EarthQuaker Devices The Depths Review

An analog modulation pedal inspired by the Uni-Vibe—but with some compelling new twists.

Modern music history is littered with instruments that failed at their original mission, only to become something more interesting in creative hands. Synthesizer horns, analog drum machines, home organ banjo sounds: None of them authentically replicated the sounds that inspired them, yet all became great tools of expression on their own merits. You can make a case that the original Univox Uni-Vibe falls in that category.

Conceived to replicate the rich and complex sounds of a rotating speaker, the Uni-Vibe was charged with an unenviable task that the best DSP technology has only now tackled with real success. But if the Uni-Vibe didn’t sound exactly like a Leslie, its rich phasing and chorus effects were glorious, particularly in the hands of exploratory players like Hendrix, Trower, and Gilmour.

With its light/optical circuit, EarthQuaker’s The Depths is inspired in no small measure by the Uni-Vibe. But in typical EarthQuaker fashion, it tweaks a classic formula to more expressive and more practical ends.

Compact, Potent Vibrations The pedal’s exterior is dressed up with a hybrid octopus/bathysphere graphic that gets our vote for coolest stompbox art of the year. Just above, five knobs are arrayed in an X-shape: control, intensity, level, rate, voice, and throb. The first three are self- explanatory. The latter two shape the output tone and add low-end emphasis to the modulation, respectively, expanding the range of musical scenarios where The Depths can shine.

There’s a lot going on in the depths of The Depths’ compact enclosure. Cracking it open reveals a tidy PCB-mounted optical circuit. Such circuits work by placing a small lamp adjacent to a light-sensing photocell so that the rate and intensity of the light control the effect. You can actually observe the lamp reacting as you adjust controls: Turning the voice control clockwise makes the lamp brighter. It blinks faster as you advance the rate settings. And intensity adjustments make the light swell in brightness more or less gently. In a number-crunching DSP age, it’s a fascinatingly anachronistic technology that generates organic and nuanced modulation tones.


Deep, beautifully countered modulations. Great speed and depth range. Powerful tone-shaping controls.

No expression pedal option.


Ease of Use:





Bubbling Up, Getting the Bends Like most good Uni-Vibe style effects, The Depths is beautifully musical at mellow settings. Keeping the rate low and the intensity at about noon that adds a funky, psychedelic character to slow, bluesy Hendrix-style licks or meandering Jerry Garcia-style lead runs. Slow rate settings also make it easy to hear the gently contoured waveform that defines The Depths’ basic voice. It’s fluid, harmonically rich modulation that can be tailored to fit an arrangement, mood, or rig via the voice and throb knobs.

Bass-heavy voice and throb settings add emphasis and power to low-end modulations, making The Depths sound positively abyssal at slow rates. Fast rate settings, meanwhile, benefit from treblier voice settings and less pronounced throb settings, which sharpen modulations and lend definition as things speed up.

The level knob is a valuable and powerful addition, given how intense and how focused in the EQ spectrum these modulations can be. Aggressive voice and throb settings blunt high-mid content and emphasize the volume drop most players perceive in heavy modulation situations. I typically kept the level at two o’clock or higher, which kept the modulations pronounced while adding a little overdrive color.

The Verdict The Depths addresses nearly every complaint anyone ever had with a Uni-Vibe. For some purists, the lack of a rate pedal like that on the original may offset the added tone-tailoring power. But with its improved tonal range and musical versatility, The Depths can be an invaluable weapon for studio and stage players who like to hone modulation sounds for a given song. The Depths delivers all this flexibility with an analog circuit and a beautiful, vintage-flavored voice. It’s a cool evolution of a cool effect.

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