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Aaron's Bass Hole: Decoding the Data Corrupter

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Aaron's Bass Hole: Decoding the Data Corrupter

Aaron Rogers

In the few weeks since its release, the Data Corrupter Modulated Monophonic Harmonizing PLL has been called everything from the new holy grail of effects pedals to an abomination; the latest infraction in EarthQuaker’s musical crime spree. Like it, love it, or loathe it, it’s not going anywhere. And if building an awesome retro-futuristic six-octave synth-inspired sound destroyer is a crime, then lock us up and throw away the key, because if the Data Corrupter proves anything, it’s that sometimes it feels good to be bad.

Background Noise

The PLL (Phase Locked Loop) is an anomaly among effects pedals because the circuit was never intended for musical applications. A quick Wikipedia search shows that the earliest physics experiments which eventually led to the development of PLL technology date all the way back to 1673! Around this time, the Dutch physicist Christiaan Huygens observed that two unsynchronized pendulum clocks, when acoustically coupled by a wooden beam, would align themselves, becoming in sync, and thus in phase.

A few centuries later, in 1932, British researchers working to develop a more stable radio receiver discovered they could correct a drifting oscillator by introducing an “automatic correction signal,” which could be tuned so that the sum of the two signals, when combined, produced a more stable version of the original signal with the desired frequency and phase. This discovery was immediately put to use strengthening radio broadcast signals and stabilizing television transmissions.

French scientist Henri de Bellescize, who is often credited for inventing the PLL, described such a system in a 1932 paper published in the journal L’Onde Électrique. A few decades later, in the early 70s, RCA developed the CD 4046 CMOS Phase Locked Loop IC, which is the basis for most musical PLL circuits, including the Data Corrupter. The most infamous of these circuits lurks within the Schumann PLL.

The Schumann PLL gained notoriety among outsider artists and weirdos for its sputtering, unpredictable, squelchy outbursts of sound. By comparing an instrument’s audio waveform against a tunable oscillator, the PLL generates a new synthesized tone, which may be manipulated further by multiplying or dividing the synthesized frequency, thus introducing octaves, suboctaves, and harmonies. With only a rumored fifty or so units in existence, the Schumann PLL has a rabid, Klon-like cult following who pay upwards of three thousand dollars for one of these elusive (and finicky) devices.

The most notable Schumann PLL user is Justin Pearson of Dead Cross, the Locust, Retox, and Head Wound City. In his PedalsAndEffects interview with Jonathan Hischke, Pearson speaks of his encounter with Schumann, who built and sold the PLL exclusively at Brooklyn’s Main Drag Music, and can be heard on the Locust songs “Safety Second, Body Last,” and “Live From the Russian Compound.”

Plague Soundscapes

The Data Corrupter honors the tradition of pioneers like Schumann, Bellescize, and Huygens by distilling the essence of the PLL circuit so often used in telecommunications into a compact, intuitive, and predictable (but not too predictable) package designed for use with musical instruments.

While some may be disarmed by the sheer number of possibilities, tracing the Data Corrupter’s signal flow is actually quite simple. Treating each section of the Data Corrupter as an individual sonic building block will have you constructing wild, yet repeatable three-part fuzzed out harmonies in no time.

Beginning with the Master Oscillator’s “Root” switch, you can “tune” the Data Corrupter to play nicely with your instrument’s frequency register. On the bass guitar, I find the “Unison” position to be the most stable, but guitarists exploring the upper reaches of the neck may want to set the “Root” switch to one or two octaves down to aid the Data Corrupter in accurately dividing these higher frequencies.

From there, you can select the Data Corrupter’s upper voice using the “Master Oscillator” rotary switch. There are eight Master Oscillator programs to choose from, beginning with a true unison signal, all the way up to three octaves above the input.

Next, the “Subharmonic” rotary switch allows you to choose one of eight lower octave programs from one octave down, all the way down to a whopping three octaves plus a major second below the input. 

The Subharmonic voice has its own “Root” toggle switch, which allows the Subharmonic to be calculated from either your input signal (Unison), which provides a more stable lower octave, or from the Master Oscillator (Oscillator), which can create whacked-out harmonies and expressive envelope phasing as the two voices interact.

The Frequency Modulator is the real wild card in the Data Corrupter’s hand. Its two modes, “Vibrato” and “Glide” are selectable via mini-toggle, and they both share the “Rate” control at the center of the Device.

“Vibrato” mode produces a squiggly sci-fi laser gun effect as the Frequency Modulator LFO quickly raises and lowers the Master Oscillator pitch. In “Glide” mode, the Data Corrupter will slide between notes much like the portamento feature on an analog synthesizer. With the Subharmonic Root switch set to “Unison,” the Frequency Modulator operates only on the Master Oscillator’s upper octave signal. When the Subharmonc Root is set to “Oscillator,” modulation is applied to both the upper and lower voices.

Finally, the Data Corrupter’s output section has a Voice Mixer to adjust the relative volume of the Subharmonic, Oscillator, and unison Square Wave Fuzz voices, as well as a master Level control, to set the output being sent to the amplifier. Clear as mud, right?

How’s It Sound?

Depending who you ask, the Data Corrupter sounds like a broken old dial-up modem, internet trolls bickering back and forth in an eternal YouTube comments troll-off, a giant robot fighting another robot, killing it, ingesting its circuitry and throwing it back up; psychedelic space cats having an epic laser gun battle, or my personal favorite, “farts in the key of shit.” Take your pick. All are valid, except for maybe that last one. (G.G. Allin notwithstanding).

Anyway, the Data Corrupter’s analog circuitry gives it a rich, harmonically complex, and expressive musical voice with stable, instantaneous tracking, courtesy of its rock solid oscillators. How you use it is up to you. Below are audio examples of five cool sounds I’ve unlocked.

Example 1

In this example, I’m playing a Kala U­­·Bass for some upright-style low end thump. I’m running it into a Darkglass Super Symmetry compressor, which then goes to a Tronographic Rusty Box preamp, into the Data Corrupter, through a SansAmp RBI, and into a MOTU 8pre. I’m using Reaper as my DAW. In this, and all other examples, I’m blending in a clean signal taken from the Rusty Box and recorded onto its own track.

The Data Corrupter setting is as follows:

  • Master Oscillator Root: Unison
  • Master Oscillator: +2 octaves
  • Frequency Modulator: Glide Mode, Rate set to max
  • Subharmonic: -2 octaves
  • Subharmonic Root: Oscillator
  • Square turned all the way off, Subharmonic and Oscillator voices mixed to taste.

The inter-oscillator modulation produced by the Frequency Modulator lends this creepy sci-fi horror inspired lick an extra layer of spookiness, while flipping the Frequency Modulator switch to “Vibrato” during a sustained note sends the Data Corrupter into full-on freak out mode, which I find useful when punctuating between phrases.

Example 2

Now I’ve switched from the U­­·Bass to my Electrical Guitar Company Series One for a slightly more traditional electric bass sound. The rest of the signal path remains unchanged.

Here I use the Master Oscillator’s +2 octaves and a fifth setting to mimic Dr. Dre’s stacked oscillator Moog bass sounds. Although if you listen to my sloppy playing, it’s clear that “Gin & Juice” is about the last thing I need.

Here’s the setting:

  • Master Oscillator Root: Unison
  • Master Oscillator: +2 octaves and a fifth
  • Frequency Modulator: Glide mode, Rate backed off just enough for slight portamento
  • Subharmonic: -2 octaves
  • Subharmonic Root: Unison
  • All three voices mixed to taste

Setting the Subharmonic Root to Unison produces a more stable lower octave so you can shake the subs with confidence, and backing off the Frequency Modulator Rate allows each note to subtly slide into the next, which is exactly what you need for those greasy G Funk basslines.

Example 3

Speeding things up a bit, this next example draws inspiration from Justin Pearson’s use of the PLL in the Locust, using all three voices as I attempt to demonstrate the Data Corrupter’s utility in a chaotic noisy punk setting.

Here it is:

  • Master Oscillator Root: Unison
  • Master Oscillator: +3 octaves
  • Frequency Modulator: Glide, Rate set to about 3 o’clock
  • Subharmonic: -3 octaves
  • Subharmonic Root: Oscillator
  • All three voices mixed to taste

Example 4

So far I’ve played it relatively safe, sticking to perfect intervals like octaves and fifths, and for the most part staying away from the Frequency Modulator’s “Vibrato” mode. You wanna get nuts? Let’s get nuts.

This example (which I nicked from Trans Am’s “Play In The Summer”) takes advantage of the Master Oscillator’s diatonic harmonies to dial in two octaves up, plus a minor seventh. To make the Data Corrupter act extra squirrely, I’ve set the Frequency Modulator to “Vibrato” mode, with the rate set to about 1 o’clock.

Check it:

  • Master Oscillator Root: Unison
  • Master Oscillator: +3 octaves
  • Frequency Modulator: Vibrato, Rate set around 1 o’clock
  • Subharmonic: -1 octave and a fifth
  • Subharmonic Root: Unison
  • All three voices blended to taste

Example 5

Last but certainly not least, here’s the EGC tuned to Drop-D with the bridge pickup soloed, driving the Data Corrupter’s Square voice for a standalone fuzz. No muss, no fuss. Used as a bass fuzz, the Data Corrupter has plenty of upper-midrange grind to situate the bass in the mix, while the unique attack envelope and synthy, gated decay reminds us that this ain’t your blues lawyer’s fuzz box. We wouldn’t want it any other way.


Aaron Rogers does Copywriting & PR at EarthQuaker Devices. He also works as a freelance live sound engineer and plays the bass guitar in Ultrasphinx.