The KMA Machines Mandrake is an all-analog upper-octave fuzz pedal, launched in November 2023 under the full name Mandrake Octo-Shrieker12. It takes the octave-up fuzz circuit that KMA built into its Moai Maea pedal, refines it, and puts it in a stand-alone box with a fuzz voicing control of its own13. The result is a pedal that stacks a fuzzy upper octave on top of your dry signal, in whatever balance you set.
KMA describes the character as "edgy and fuzzy character that's reminiscent of many of the best vintage octave-up devices"1. Octave-up pedals of this kind have a long history on pedalboards; KMA's own page notes that players including Hendrix, Tony Iommi, Josh Homme, Billy Corgan and Jack White have used octave-up pedals generally1.
How the circuit works
The Mandrake is a discrete transistor-based fuzz with what KMA calls an "enhanced rectification circuit topology," designed to produce a more robust and present upper octave13. Ahead of the fuzz it has an active, pre-gain 2nd-order filter section, which KMA says is designed to prepare any instrument's signal for octaval tones1. In practice, that pre-gain filtering is what helps the octave track cleanly, and Delicious Audio highlights the pedal's "ultra-fast tracking"3.
Guitar World reported that KMA's design goal was to rectify the untamed and "nasty" clashing overtones that can arise from octave effects, and that the pedal is not a one-trick pony octave-up device5.
The controls
Four knobs shape the sound. The two larger knobs handle the octave voice; the two smaller knobs at the bottom set the mix3.
| Control | What it does |
|---|---|
| Filter | Low-pass filter that tames upper harmonics and improves tracking. Fully left: unhinged, cutting, shrieking mayhem. Fully right: more mellow, blooming, synth-like texture1 |
| Timbre | Sets the amount of fuzzy gain in the upper octave. Fully counterclockwise: slightly crunchy and percussive. Fully clockwise: a crushingly saturated doom-hammer1 |
| Dry | Sets the level of your clean, unprocessed signal in the mix13 |
| Oct+ | Sets the level of the effected upper octave13 |
Because Dry and Oct+ are independent level controls rather than a single blend knob, you can run the octave alone, the dry signal alone, or any balance between them1. Gearnews found the control set well judged: "This could be a great fuzz/upper octave effect and the controls are just complex enough to control the octave effect"2.
The Shriek circuit it comes from
The Mandrake is based on a highly refined and improved version of the Shriek circuit from KMA's Moai Maea pedal1. The Moai Maea is a larger analog octaver that also offers down-octaves, sub-octave drones and a clean blend, alongside the fuzzy octave-up Shriek channel6. With the Mandrake, KMA extracted that Shriek channel, improved it, and added the Timbre fuzz voicing so the octave voice can be pushed from crunchy to fully saturated4. MusicRadar described the company as having "gone rummaging in the circuitry of its Moai Maea for inspiration"7.
The pedal is made in Berlin, Germany4, and uses top-mounted jacks for pedalboard-friendly routing2.
The Mandrake runs only on external power: 9V DC, center negative, 2.1mm barrel, with a maximum current draw under 30mA1. There is no battery option, so it needs a spot on a power supply.
What reviewers said
Reactions at launch were positive. Guitar Pedal X called it "just a great concept really well executed" and praised its "apt graphic treatment"4. In Guitar Pedal X's roundup of the best new fuzz pedals of 2023, Stefan Karlsson named it "another really fantastic sounding octave fuzz with extended controls"8. Gearnews summed it up as a potentially great fuzz/upper-octave effect whose controls are complex enough without becoming awkward to dial in2.
Videos
KMA Machines
BassTheWorld.com
The Pedal Zone
Questions
Is the KMA Machines Mandrake analog or digital?
It is fully analog. KMA Machines describes it as an all-analog upper-octave fuzz built on a discrete transistor-based fuzz circuit with an enhanced rectification topology, plus an active pre-gain filter section that prepares the instrument signal for octave tones.
Is the Mandrake true bypass?
Yes. It uses true bypass with silent relay-based soft switching, so the pedal pops less when engaged and leaves your clean signal untouched when it is off.
What does the Filter knob do on the Mandrake?
It is a low-pass filter that tames the upper harmonics and improves tracking. Fully counterclockwise the pedal is unhinged and shrieking; fully clockwise it becomes more mellow and blooming, with a synth-like texture. Delicious Audio describes it as an EQ knob that gets bassier at higher settings.
Can I blend the dry signal with the octave on the Mandrake?
Yes. The two smaller knobs, Dry and Oct+, set the dry signal level and the octave level independently, so you can keep your original guitar tone under the fuzzed upper octave in any proportion you like.
What power does the KMA Mandrake need?
A 9V DC center-negative 2.1mm power supply. Maximum current draw is under 30mA, so it is easy on a pedalboard power supply. KMA lists the power supply as optional, meaning the pedal does not run on a battery.
How much does the KMA Machines Mandrake cost?
At launch in November 2023 it listed at $169.99 in the US, €169 in the EU and £149 in the UK. Guitar World reported it as available then for $170.
Sources (8)
- MANDRAKE, KMA Machines
- KMA Machines Mandrake Octo-Shrieker, gearnews.com, 2023-11-07
- KMA Machines Mandrake Octo Shrieker Fuzz, Delicious Audio, 2025-07-09
- Guitar Pedal X, Guitar Pedal X, 2023-11-07
- “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, Guitar World, 2023-11-08
- Guitar Pedal X, Guitar Pedal X, 2023-10-13
- KMA Machines launches the Mandrake Octo-Shrieker, promising player-friendly octave-up fuzz magic from a compact, tweakable stompbox, MusicRadar, 2023-11-07
- Guitar Pedal X, Guitar Pedal X, 2023-12-18
