The KMA Machines Mandrake Octo Shrieker is an octave-up fuzz pedal: a fuzz circuit that generates a note one octave above what you play, with a dry mix knob that lets you blend the effected and clean signals. The fuzz circuit is transistor-based, and KMA describes its enhanced rectification circuit topology as delivering a more robust tone. It comes in a compact enclosure with top-mounted jacks1.
Controls
The pedal has four knobs, arranged as one large knob at the top and two smaller ones at the bottom, plus the Timbre control at the core of the circuit2.
| Control | What it does |
|---|---|
| Timbre | Sets the amount of gain, the core of the fuzz circuit2 |
| Filter | An EQ knob that gets bassier at higher settings2 |
| Oct+ | Controls the amount of octave-up signal2 |
| Dry | Controls the amount of dry signal2 |
KMA describes the octave tracking as ultra-fast, with the variable Timbre and Filter controls shaping the tone around it2. Because the dry and octave signals have separate level knobs, you can run the Octo Shrieker as a clean boost with a whisper of upper octave behind it, or push the Oct+ knob up for the full dual-octave grind the maker describes2.
Circuit and origins
The Octo Shrieker's circuit is a discrete transistor-based fuzz with an enhanced rectification circuit topology, which KMA says delivers a more robust and present upper octave2. Rectification is how the circuit produces the octave: it folds the waveform of your note so the resulting tone sits an octave higher, and the enhanced topology is KMA's refinement of that stage.
The circuit itself is not new ground for the company. Guitar Pedal X described the pedal as KMA extracting and improving on the Moai Maea's analog upper octave Shriek channel, with a fuzz voicing added for the stand-alone release3. Delicious Audio's Paolo De Gregorio called it "the Berlin-based company refinement of the octave-up fuzz circuit"2.
How it fits alongside KMA's other fuzzes
KMA Machines has built out a fuzz and distortion line in recent years, and the Mandrake sits in it as the octave specialist. The company's other recent releases include the Chief Disruptor, a Big Muff-style fuzz distortion with footswitchable parametric mids1, and the Fuzzly Bear 2, a rehoused version of its first production pedal based on the '70s Jordan Boss Tone silicon fuzz4. Where those are voicing-focused fuzzes, the Mandrake's whole purpose is the octave-up effect, and it is the only one of the group built around rectification rather than straight clipping.
The Mandrake Octo Shrieker is a stand-alone extraction of one channel of the Moai Maea octave-drone pedal. If you already own a Moai Maea, the Shriek section covers similar ground, though KMA refined the circuit and added the fuzz voicing for this release3.
Videos
KMA Machines
BassTheWorld.com
The Pedal Zone
Questions
Is the KMA Mandrake Octo-Shrieker true bypass?
Yes. The pedal uses true bypass with silent relay-based soft switching, so the signal passes untouched when the effect is off and the pedal does not produce an audible click when you change states. Relay-based switching is an electronic alternative to a mechanical footswitch contact, and KMA has used it across several of its recent pedals.
What do the Timbre, Filter and Oct+ knobs do?
Timbre is the core of the fuzz circuit and sets the amount of gain. Filter is an EQ knob that gets bassier at higher settings. Oct+ controls the amount of octave-up signal in the mix, and a second small knob alongside it sets the amount of dry signal, so you can blend the upper octave against your clean tone.
Is the Mandrake Octo-Shrieker analog?
Yes, it is an analog upper octave pedal. The fuzz circuit is discrete transistor-based rather than built around integrated circuits, with an enhanced rectification circuit topology that KMA says delivers a more robust and present upper octave.
Where does the Octo-Shrieker circuit come from?
The circuit is extracted from the Shriek section of KMA Machines' Moai Maea octave-drone pedal. KMA refined that octave-up fuzz circuit for stand-alone use and added a fuzz voicing, releasing the Mandrake Octo-Shrieker as its own pedal in November 2023.
Where are the jacks on the Mandrake Octo-Shrieker?
The pedal has a compact enclosure with top-mounted jacks, which KMA says will fit into any setup. Top-mounted jacks keep the pedal's footprint narrow on a pedalboard compared with side-mounted jacks.
Sources (4)
- KMA Machines launches the Mandrake Octo-Shrieker, promising player-friendly octave-up fuzz magic from a compact, tweakable stompbox, musicradar.com, 2023-11-07
- KMA Machines Mandrake Octo Shrieker Fuzz, Delicious Audio, 2025-07-09
- Guitar Pedal X, Guitar Pedal X
- “We didn't want to just make a one trick pony octave up device”: Jimi Hendrix, Tony Iommi and Josh Homme all championed the octave pedal, guitarworld.com, 2023-11-08
