The FruitFX Pedals Space Cube Phase Locked Loop (PLL) Fuzz is a fuzz pedal built around a classic phase locked loop circuit fed by the square wave of the Melon Cube Synth Fuzz. Pedal of the Day's review says the pedal creates tones that range from pitch-shifting fuzz to sub-octaves to theremin-like sounds, and describes its aim as taking your sound interstellar with sounds akin to an alien communication device1. It is a spin-off of FruitFX Pedals' best-selling pedal, the Melon Cube Synth Fuzz1, a maker known for pedals with fruit-themed names including the Coconut Compressor, Frog Pedal, CloudDriver and Melon Cube2.
How it works
A phase locked loop is a circuit that tracks the pitch of an incoming signal. In the Space Cube, the square wave output of the Melon Cube fuzz circuit feeds a classic PLL, and the result is the pedal's range of pitch-shifting, sub-octave and theremin-like tones1. The Melon Cube itself, reviewed by Pedal of the Day in December 2025, is a pulse width modulator (PWM), a blend of synthesizer and fuzz that turns the guitar into a square wave, producing everything from thick walls of fuzz to old school video game style leads3.
The controls
The Space Cube has four knobs, described by Pedal of the Day as follows1:
| Control | What it does |
|---|---|
| Vol | Adjusts the overall output volume level |
| Tone | Tone shaping |
| Wow! | Controls the intensity of the phase locked loop (PLL) |
| Rate | Lets you control the PLL's overall speed |
The Tone control carries over from the Melon Cube, where Pedal of the Day described it as a smooth Tone control3.
Who it is for
Pedal of the Day's reviewer framed the Space Cube as a pedal for players who like to experiment1:
"If you like twisting knobs, creating the sounds you might think that space alien craft would make, or just being creative..."
The same review notes that FruitFX's builder brings wild, intriguing, out-of-the-box thinking into an enclosure that is pedalboard-friendly1. Of the Melon Cube it is based on, the reviewer wrote that out-of-the-ordinary pedals are the ones they like best, describing it as part synth, part wall of fuzz3.
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Questions
What is a phase locked loop fuzz?
A phase locked loop fuzz uses a circuit that locks onto and tracks the pitch of your guitar's signal. In the Space Cube, FruitFX feeds the square wave of its Melon Cube fuzz into a classic phase locked loop, which the maker's reviewers say produces tones ranging from pitch-shifting fuzz to sub-octaves to theremin-like sounds.
What does the Wow! knob do on the Space Cube?
Wow! controls the intensity of the phase locked loop (PLL), according to Pedal of the Day's review. Alongside Rate, which sets the PLL's overall speed, it shapes how far the tracking effect is pushed, from subtle movement to the pedal's more extreme sounds.
How is the Space Cube different from the Melon Cube?
The Space Cube is a spin-off of the Melon Cube Synth Fuzz. The Melon Cube is a pulse width modulator that turns the guitar into a square wave, blending synthesizer and fuzz sounds. The Space Cube takes that square wave and feeds it into a phase locked loop circuit, adding pitch-shifting, sub-octave and theremin-like effects.
Where is the FruitFX Space Cube made?
FruitFX Pedals are hand assembled in Long Beach, California, according to Pedal of the Day's 2026 review of the Space Cube.
Does the FruitFX Space Cube have a warranty?
Yes. Pedal of the Day's review states that FruitFX pedals come with a 2-year warranty.
Sources (3)
- FruitFX Pedals Space Cube Phase Locked Loop (PLL) Fuzz, Pedal of the Day, 2026-05-19
- Blueberry Buffer by FruitFX, RockBoard PedalPedia, 2026
- FruitFX Pedals Melon Cube Synth Fuzz, Pedal of the Day, 2025-12-13
