Molten Voltage Big Muff MIDI

The Molten Voltage Big Muff MIDI is a programmable, modified analog fuzz pedal that puts the classic Electro-Harmonix Big Muff Pi sound under MIDI control. Molten Voltage built it on the original Big Muff Pi circuit board, kept the audio path all-analog, and added a MIDI layer that stores and recalls 128 presets, switches the pedal in and out via relay true bypass, and works with any MIDI controller¹.

Molten Voltage announced the pedal on 18 February 2015, describing it as "an easy-to-use all-analog classic fuzz pedal, featuring MIDI control"²¹. The product page now marks it as discontinued¹.

What it is and what it does

The Big Muff MIDI takes a familiar idea, the Big Muff Pi fuzz, and makes it programmable. The underlying circuit is the one Electro-Harmonix has used since the Big Muff Pi's beginning in 1969, a design that has gone through many circuit variants over the decades while keeping its characteristically scooped-mids fuzz sound³. Kit Rae's technical analysis of the circuit describes it as "based on a common amplifier design with clipping diode/feedback loops"⁴, the arrangement that produces the Big Muff's thick, sustaining fuzz. Electro-Harmonix lists its own current Big Muff Pi as an analog pedal with true bypass⁵, and the Big Muff MIDI carries the same analog signal approach with a modified, MIDI-equipped implementation.

For a player, the point of the pedal is recall. A stock Big Muff Pi has three knobs, and any setting you like is gone the moment you turn one. The Big Muff MIDI saves those settings as presets and brings them back on command, so a board built around MIDI can call up a fuzz sound mid-song without bending down¹⁶.

How it is controlled and powered

Molten Voltage kept the control scheme deliberately simple. Programming is done by toggling a switch, which the company described at launch as "Simple to program - just toggle a switch!"². Once settings are stored, the pedal recalls them from any MIDI controller¹.

The hardware details from the maker's page¹:

• Presets: Store and recall 128 presets
• Bypass: Relay true bypass, activated by MIDI Program Change
• Footswitch: Soft-touch bypass switch for manual engagement
• Power: Upgraded "BOSS-style" power connection, the same barrel type used on Boss pedals
• Construction: Solid, professional-grade build, including a riveted steel MIDI jack

The relay true bypass is worth noting for players who leave pedals on a board: the pedal drops out of the signal path entirely when bypassed, and the switching can be driven remotely by MIDI Program Change messages rather than only by the footswitch¹.

How it differs from a stock Big Muff Pi

A stock Electro-Harmonix Big Muff Pi is an analog, true-bypass fuzz with volume, tone, and sustain controls and no memory⁵. The Big Muff MIDI keeps the analog fuzz circuit but adds the digital control layer: 128 presets, MIDI program changes, and relay bypass switching¹. In that respect it resembles the approach Electro-Harmonix later took with its own Big Muff Pi Hardware Plugin, which MusicRadar's reviewer described as having an entirely analog guitar signal path with digitized controls giving the pedal a memory, though that is a separate Electro-Harmonix product, not a Molten Voltage one.

The practical difference for a player is board integration. A conventional Big Muff is a stompbox you set by hand; the Big Muff MIDI behaves like a MIDI-addressable unit, one of many devices a central controller can switch. Molten Voltage built a range of such MIDI devices, including the Molten Voltage MASTER CONTROL and Molten Voltage Molten MIDI 2, and the Big Muff MIDI fits that ecosystem while also working with any other controller¹.

Where it came from

Molten Voltage announced the Big Muff MIDI on its blog on 18 February 2015, presenting it as a MIDI-controllable fuzz pedal with 128 presets and relay true bypass²¹. The company positioned it as an easy-to-use pedal rather than a complex programmable unit, emphasizing the single-switch programming. The product page lists it as discontinued as of October 2026¹, so the pedal is no longer in production and is available only on the used market.

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