Molten Voltage Professional Molten Voltage Big Muff MIDI

The Molten Voltage Big Muff MIDI is a programmable, modified analog fuzz pedal built by Molten Voltage Professional. It takes the original Electro-Harmonix Big Muff Pi circuit board and adds MIDI control, so a player can store and recall 128 presets, switch the pedal in and out with relay true bypass triggered by MIDI Program Change, and run it from any MIDI controller¹. Molten Voltage describes it as "an easy-to-use all-analog classic fuzz pedal, featuring MIDI control"¹.

The Molten Voltage Big Muff MIDI is an all-analog classic fuzz pedal with relay true bypass activated by MIDI Program Change¹. It is built with a soft-touch bypass switch, an upgraded "BOSS-style" power connection, and solid, professional-grade construction including a riveted steel MIDI jack¹.

A Big Muff fuzz with MIDI control

The idea behind the Big Muff MIDI is straightforward: keep the analog fuzz circuit players know, but make its settings recallable. A stock Big Muff Pi has three knobs, VOLUME, TONE, and SUSTAIN, and any change means reaching down and turning them mid-song². The Big Muff MIDI instead stores complete settings as presets, 128 of them, and recalls them over MIDI¹.

Molten Voltage lists these features on its product page¹:

• Works with any MIDI controller
• Store and recall 128 presets
• Relay true bypass activated by MIDI Program Change
• Soft-touch bypass switch
• Upgraded "BOSS-style" power connection
• Solid, professional-grade construction including a riveted steel MIDI jack

The relay true bypass point matters for players who leave the pedal on a board: the pedal can be switched in and out of the chain remotely from a MIDI controller, not only from its own soft-touch footswitch¹. The "BOSS-style" power connection means it takes the same barrel connector and polarity convention as Boss compact pedals, the most common standard on pedalboard power supplies¹.

Programming is deliberately simple. Molten Voltage's description, on both the product page and the original 2015 announcement, is "Simple to program - just toggle a switch!"¹³. There is no menu diving or editor software: set the pedal, toggle the switch to store, and the preset is then available for recall from a controller.

The Big Muff Pi circuit inside

The pedal uses the original Big Muff Pi circuit board, the same basic design Electro-Harmonix has built since the Big Muff was created around 1969/1970¹⁴. Kit Rae, whose kitrae.net site holds the most detailed published histories of the circuit, describes it as a five-stage design: an input/gain stage, a first clipping stage, a second clipping stage, a tone stage, and an output stage⁴.

Two details of that circuit explain the sound players associate with the Big Muff:

• Two clipping stages in a row. The circuit has "two nearly identical clipping sections in a row, one clipping an already distorted signal," which stacks distortion on distortion for the high-sustain character⁴. Most modern Big Muffs and clones use general-purpose 1N4148 or 1N914 diodes for this clipping⁴.
• A scooped-mid tone stage. The signal splits into a high-pass and a low-pass filter, which are blended back together by the tone potentiometer. Kit Rae notes this "creates the trademark mid range notch, or 'scoop' the Big Muff is so well known for"⁴.

The input stage also shapes the signal before any clipping: the input capacitor forms a high-pass filter with a cut-off frequency around 3.8 Hz, low enough that it does not disturb guitar harmonics⁵. Vintage Big Muffs were built with both PNP and NPN transistors, with no real effect on the sound either way, according to Kit Rae's analysis⁴.

Since 1969 the Big Muff Pi has gone through many circuit variants, and the four-stage circuit has inspired a large family of pedals⁶. Molten Voltage's modification keeps the analog signal path intact and layers MIDI control on top of it, an approach Electro-Harmonix itself later took with its own programmable Muffs, which the maker lists as analog circuits with digital control¹.

How it compares

Against a stock Big Muff Pi, the trade is clear: the original gives you three knobs and a footswitch at a lower price, while the Big Muff MIDI gives you preset recall and remote switching at the cost of needing a MIDI controller to make full use of it¹. Players who change fuzz settings between songs, or who run larger switched boards, are the audience MIDI control serves; players who set a fuzz once and leave it have less use for 128 presets.

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