Spaceman Effects launches the Mercury IV boost pedal

A vintage germanium transistor sits at the heart of the Mach 4 version of the popular stompbox.

Spaceman Effects Mercury IV

The Mercury IV isn’t just a boost pedal. It’s a “dynamic tone enhancer [that brings out] additional harmonic character from instruments and amplifiers,” says its creators, Spaceman Effects. And the stompbox has an all-analog circuitry with a vintage germanium transistor to thank for that.

Crank the “Boost” knob up to 11 and the Mercury IV will yield 35 dB of extra gain with a high headroom. The “Harmonics” control, on the other hand, adds sparkle, texture, overtones and even-order harmonics to your signal. And the “Low” and “High” three-way switches give you a further nine tone-shaping options. You can boost the bass, trebles and mid of both the low and high frequencies.

Hear the Mercury IV in action in this video:

The Mercury IV is available in Black, White, Silver and Metallic Brass, and lists from $299 to $349. For more information, check out


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