KMA Machines launches the Mandrake Octo-Shrieker, promising player-friendly octave-up fuzz magic from a compact, tweakable stompbox

KMA Machines has gone rummaging in the circuitry of its Moai Maea for inspiration and has reworked and improved its octave-up circuit for the Mandrake Octo-Shrieker, a guitar effects pedal that is like classic octave-ups of yore only more tweakable, more user-friendly – and more pedalboard-friendly too.

The Mandrake offers “subtle tone enhancement to full-on dual octave grind”, and presents players with ample control over the octave-up sound. KMA Machines says this new circuit is blessed with better tracking, making for a sound that’s more robust no matter how you choose to use it.

Flexibility was the goal, which is not necessarily a gimme in the world of octave-up fuzz effects. They can be temperamental, running away with themselves and letting the upper-frequency harmonics take over. 

This applies a quote/unquote “enhanced rectification circuit topology” to a discrete transistor-based fuzz, and pairs this with an active pre-gain second-order filter to keep your electric guitar’s signal pristine for the octaver. 

KMA Machines Mandrak Octo-Shrieker

(Image credit: KMA Machines)

The second-order filter is controlled by a Filter knob, and the further you turn it clockwise the smoother it gets, with quasi-synth fuzz sounds at its extreme

Set it below noon, or leave it fully counterclockwise – you animal! – and you’ll get “unhinged, cutting and shrieking mayhem”, hence the name Mandrake, which as legend has it would shriek as it was plucked from the soil, destined for a potion or poison. 

Either way, Filter is your friend when switching over from single-coil guitars to humbuckers. Timbre is another key control for shaping the octave-up voice to complement your signal. Fully counterclockwise, KMA says it might sound a bit “crunchy and percussive” but as you turn it up the sound blooms.

Once more, the extremes of a control yield an extreme sound to work with – “a crushingly saturated doom-hammer, instantly ready to wreak havoc with each power chord you throw at it!” as KMA puts it.

KMA Machines Mandrak Octo-Shrieker

(Image credit: KMA Machines)

Again, bringing things back to practicality and versatility, there is an all-important mini-dial for Mix to adjust the balance between the processed signal and the sound from your guitar, and there’s another mini-dial to control the level of the octave-up effect.

So yes, the Mandrake Octo-Shrieker, it’s an octave-up pedal for fuzzy retro sounds a la QOTSA, Jack White et al, and it can get wild, but it does subtle, too, and crucially it is easy to dial in your tone. 

The Mandrake takes 9V from a pedalboard power supply, drawing 30mA, it is true bypass, and it’s available now, priced £149. See KMA Machines for more details.

Jonathan Horsley

Jonathan Horsley has been writing about guitars and guitar culture since 2005, playing them since 1990, and regularly contributes to MusicRadar, Total Guitar and Guitar World. He uses Jazz III nylon picks, 10s during the week, 9s at the weekend, and shamefully still struggles with rhythm figure one of Van Halen’s Panama.