The Red Witch OPIA Fuzz Engine is a fuzz pedal with a difference: it has no knobs on the outside at all. Red Witch built it around the idea that the guitar's own volume control is the interface, so the player rolls the volume up for fuzz and back for clean tones, with two internal trimpots set once to taste. The maker describes the circuit, built on dual silicon transistors, as conjuring "fuzz flavours of epic proportions," running from "clean glassy highs to 'wall-of-fuzz' behemothocity."1
How it works: the guitar volume as the control
Red Witch's instructions are simple: "Place the OPIA first in your signal chain. Engage the pedal. Adjust your volume control." The pedal is intended to sit first in the chain and respond to the guitar's volume knob, taking the player from crystal cleans to massive gain without touching the pedal itself. Red Witch puts it plainly on the product page: "A pedal with no knobs?? What sort of witchcraft is this?"1
The controls: two internal trimpots
The OPIA's adjustments live inside the enclosure:
Both are set with a screwdriver and left alone in normal use; the playing-time control is the guitar's volume knob.1
The OPIA is listed as sold out on Red Witch's product page as of 26 October 2026.1
Power, size and build
The pedal draws 15mA and uses true bypass switching, so it is compatible with ordinary pedalboard power and stays out of the path when off. The enclosure measures 105mm x 50mm x 45mm and weighs 145 grams, making it a compact addition to a board of fuzz pedals. Red Witch builds it in small batches by hand in New Zealand, hand signed and numbered, and backs it with what the maker calls a 100% lifetime warranty.1
Where it sits among Red Witch's fuzzes
Red Witch's fuzz range runs from the Fuzz God IV and Fuzzotron to the Zeus Bass Fuzz Suboctave and the Euphorium Fuzz. The OPIA is the minimalist of the family: where those pedals put their voicing on external controls, the OPIA fixes its character internally and hands the rest to the player's hands.1
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Red Witch Pedals
Questions
Does the Red Witch OPIA have any knobs on the outside?
No. The OPIA has no external controls at all. Red Witch asks the player to place it first in the signal chain, engage it, and then use the guitar's own volume control to move from cleans into fuzz. Two internal trimpots handle the set-and-forget adjustments: one for overall output volume and one for bite and grit.
Is the Red Witch OPIA Fuzz Engine true bypass?
Yes. Red Witch lists the OPIA's switching as true bypass, so the pedal is out of the signal path entirely when disengaged.
How much current does the OPIA draw?
Red Witch specifies a current draw of 15mA, which is modest enough for most standard pedal power supplies.
Where is the Red Witch OPIA made?
Red Witch builds the OPIA in small batches by hand in New Zealand, and each unit is hand signed and numbered.
Is the Red Witch OPIA still available?
The pedal is listed as sold out on Red Witch's own product page as of October 2026, so it is not currently available new from the maker.
Sources (1)
- OPIA Fuzz Engine, redwitchpedals.com
