EarthQuaker Devices Data Corrupter – Modulated Harmonizing PLL


The EarthQuaker Devices Data Corrupter is a three-voice modulated monophonic phase-locked loop harmonizer. It takes your input signal and brutally amplifies it into a crushing square wave fuzz tone.

Requires 9V DC centre negative power supply. Draws approx 25 mA

(1 customer review)

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EarthQuaker Devices Data Corrupter 

The EarthQuaker Devices Data Corrupter takes its inspiration from the Electrax Synthax and the “Basic Frequency Synthesizer” by Ray Marston.

The Data Corrupter’s ability to track well and provide long sustain is the result of lots of work.

We think you’ll find it more expressive and accurate than pretty much any other PLL based effect pedal around.

There is a lot of detail here on how this works. You can hear some audio samples here.

What is the Datacorrupter?

The Data Corrupter is a monophonic analogue harmonizing PLL with modulation.

It takes your input signal and brutally amplifies it into a crushing square wave fuzz tone.

This is multiplied, divided, and modulated creating harmonically complex, analog synth tones. They are up to three octaves below, or above, the original signal, plus additional harmonies.

The Data Corrupter takes your input signal and brutally amplifies it into a crushing square wave fuzz tone.

How does it work?

The heart of the EarthQuaker Devices Data Corrupter is based around a CMOS Phase Locked Loop circuit.

In a nutshell, the PLL takes your input signal and compares its phase and frequency against an oscillator, generates an output based on their difference, then feeds it back to the oscillator.

This then causes the oscillator to lock onto the input signal and generate a synthesized frequency.

This synthesized frequency is the Master Oscillator on the Data Corrupter.

The Master Oscillator

The Master Oscillator’s “Root” adjusts the frequency range and tracking response of the input signal.

It is the octave which is selectable via a three-position rotary switch.

This is then synthesized and harmonized by one of eight Master Oscillator programs, adjustable by an eight-way rotary switch.

From there, the Frequency Modulator applies pitch-bend to the Master Oscillator.

In Glide mode, you’ll hear a smooth portamento as each note slides into the next.

In Vibrato mode the pitch modulates up and down for a retro sci-fi laser effect.

The subharmonic puts the input signal into one of eight lower octave programs between one and three octaves below the original.

In use

To unleash the cracked machine lurking within the Data Corrupter mainframe, set the Subharmonic Root switch to Oscillator.

Try not to look away as the sonic malware you just installed mangles your input signal into the sum and difference of both the Master Oscillator and Subharmonic.

For a more stable lower octave, set the subharmonic’s Root switch to the Unison position.

This divides the Square Wave input signal and removes the Frequency Modulator from the Subharmonic signal path.


Master Oscillator

Unison, one octave down and two octaves down inputs to the Master Oscillator.

Some frequencies are too high for the Master Oscillator to divide, therefore, shifting them down one or two octaves brings them back into the proper range and it also sounds super cool.

These sources are referred to as “Root” and can be selected via a three-position switch.

The Root is then fed into the PLL and multiplied to create one of eight different intervals over three octaves.

The Frequency Modulator section manipulates this harmony.

Frequency Modulator

The Frequency Modulator has two modes, Glide and Vibrato.

In Glide mode, the pitch glides from note to note.

The speed of the glide is adjusted by the Rate control. At faster settings, this takes on a very cool phase shifting effect.

In Vibrato mode, the pitch varies up and down to create a laser-like effect.

The Frequency Modulator only affects the Master Oscillator, unless the Subharmonic Root switch is in the Oscillator position.

The Frequency Modulator applies pitch-bend modulation to the Master Oscillator. In Glide mode, you’ll hear a smooth portamento as each note slides into the next.

In Vibrato mode the pitch modulates up and down for a retro sci-fi laser effect.


The Subharmonic section of the Data Corrupter creates a sub-octave of the Root and then divides it up into eight intervals over three octaves.

These are selected by the rotary switch to create your subharmonic harmony.

The Root comes from either Unison or the Master Oscillator.

When Unison is selected, the Subharmonic is a division of the square wave fuzz tone, and the Frequency Modulator ineffective.

When Oscillator is selected, the Subharmonic is a division of the Master Oscillator and the Frequency Modulator applied to the Subharmonic harmony.

Voice Mixer and Level

The Master Oscillator, Subharmonic and Square wave fuzz tone all have volume controls under the voice mixer section.

Use these to blend the three voices together to taste. The Level is a master volume and determines the overall output level of the effect.


For best tracking, place the pedal at the front of the signal chain and before any delay, reverb or modulation effect.

While it will work with most bridge pickups, the neck pickup will provide the best tracking results. Precise picking and single notes will track quickly and cleanly.

Chords and sloppy playing will result in chaos.

There is no gain control because weak signals (like backing off on the guitar volume) will lead to poor tracking and gating.


  • Wild Three-Voice Guitar Synthesizer w. Crushing Square Wave Fuzz
  • Frequency Modulator produces smooth portamento pitch-bends in Glide mode, or retro sci-fi laser effects in Vibrato mode
  • Master Oscillator and Subharmonic dials allow for harmonies up to three octaves above and below your original signal
  • True Bypass
  • Silent relay-based switching
  • All-analog signal path
  • Top-mounted jacks – for effortless pedalboard implementation
  • Measures:5.65″ x 4.75″ x 2.25″ with knobs


The EarthQuaker Devices Data Corrupter requires s 9 volt DC power supply with a 2.1mm negative centre barrel – 25mA.

We always recommend pedal-specific, transformer-isolated wall-wart power supplies or multiple isolated-output supplies.

Pedals will make extra noise if there is ripple or unclean power. Switching-type power supplies, daisy chains, and non-pedal specific power supplies do not filter dirty power as well and let through unwanted noise. Do not run at higher voltages!

Additional information

Weight 0.5 kg
Dimensions 14.4 × 12.1 × 5.7 cm
Analogue or Digital



Black, White


25 mA



Pedal Type

Harmoniser, Modulation

Power Connection Type

Centre Negative

Silicon or Germanium




EAN 13





Data Corrupter

1 review for EarthQuaker Devices Data Corrupter – Modulated Harmonizing PLL

  1. Dan G (verified owner)

    Craziest stuff I ever bought

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