The EarthQuaker Devices HalfLife is an octave distortion and booster pedal built in collaboration with the drone metal band Sunn O))). EarthQuaker describes it as "a distortion with a blendable analog octave up and a booster combined in one compact package"1. Under the hood it is a Rat-style distortion circuit paired with an analog octave-up and a clean boost, and it is the most compact, pedalboard-friendly version of the Life Pedal distortion circuit to date1.
The signal path runs Octave > Distortion > Boost1. The octave is an all-discrete analog full-wave rectifier circuit, and the final stage is an all-discrete MOSFET booster that EarthQuaker calls 100% clean and high impedance1. Gearnews describes that boost stage as adding "no colouration or clipping, engineered to drive tube amplifiers into total harmonic saturation and feedback"2. Guitar Pedal X frames the whole thing simply: "The Life Pedal / HalfLife essentially being a Rat Distortion + Boost + Octave"3.
What it does to your sound
The HalfLife combines three things in one box: a high-gain distortion voiced like a vintage white-logo RAT, a blendable octave-up that sits above your original note, and a clean boost at the end of the chain. Guitar World's Paul Riario writes that the circuit is "inspired by the vintage Shin-Ei FY2 Companion and FY6 Super Fuzz boxes and a vintage white-logo RAT distortion-style circuit"5.
The distortion side offers about +60dB of gain1, and gearnews describes the combined result as "a wall of Doom-laden tones perfect for low-tuned madness at extremely high volumes"2. For players who already know Rat-style distortions, Guitar Pedal X's Stefan Karlsson suggests the appeal is straightforward: "If you like Rat Distortions - you're quite likely to enjoy the extra boost and upper octave - which delivers a fabulous thick wall-of-sound texture"3.
A three-way clipping switch lets you choose between op-amp, asymmetric and symmetric clipping modes4, which gearnews calls "a three-way clipping switch to match any rig"2.
The controls
EarthQuaker's product page lays out five knobs, a clip switch and two footswitches5:
| Control | What it does |
|---|---|
| Octave (O) | Blends in the analog octave as you turn it clockwise1 |
| Distortion (D) | More distortion clockwise, less counterclockwise; about +60dB of gain1 |
| Filter (F) | Low pass filter, roughly 500 Hz to 30 kHz; counterclockwise for more high-end, clockwise for less1 |
| Magnitude | Output volume for the boost35 |
| Amplitude | Output volume for the octave distortion53 |
| Clip switch | OpAmp / Asymmetrical / Symmetrical clipping3 |
| Amplitude footswitch | Activates the octave distortion1 |
| Magnitude footswitch | Activates the boost1 |
The two halves of the pedal work independently. EarthQuaker states plainly that "the octave distortion and booster can be used independently with their own respective footswitches"1, so the clean boost can run on its own as a simple volume lift, or stack after the distortion to push an amplifier harder. The pedal ships with EQD's Flexi-Switch Technology, which lets the footswitches work in both momentary and latching fashion4.
There is also an expression option: the Octave EXP jack accepts any expression pedal to control the analog octave blend1, giving you foot control over how much of the upper octave is mixed in while playing. Guitar World lists the pedal's connectivity as "2 x 1/4\" instrument and 1 x 1/4\" Octave Expression input"5.
Power and specifications
The HalfLife takes a standard 9 volt DC power supply with a 2.1mm negative center barrel, and EarthQuaker warns not to run it at higher voltages1. Current draw is 15 mA1, the same figure Guitar World lists alongside its 9V DC center-negative power spec5.
| Specification | Value |
|---|---|
| Current draw | 15 mA1 |
| Input impedance (octave distortion side) | 1 MΩ1 |
| Input impedance (booster side) | 500 kΩ1 |
| Output impedance | <1 kΩ1 |
| Warranty | Lifetime4 |
EarthQuaker Devices says not to run the HalfLife at voltages above 9V DC. Use a standard center-negative 9V supply.
History and versions: the fourth Life Pedal
The HalfLife is the fourth iteration of the Life Pedal, following V1, V2 and V33. The original Life Pedal was a limited collaboration between Sunn O))) and EarthQuaker Devices, and Delicious Audio notes that the first version "ended up becoming much sought-after in the used market," which prompted the release of a second version6. Gearnews had covered three limited editions of the pedal before EQD announced the V2, a reissue of the original released the previous year7. The V2 kept the same circuitry, controls and tones as the original but in a smaller enclosure8, and the V3 followed as the third incarnation of the Life Pedal89.
The HalfLife differs from all of those in two ways. First, it is a general release rather than a limited run: Guitar Pedal X calls it "a compact, general-release HalfLife, the fourth Life Pedal iteration"3. Second, the circuit has been reworked. The original Life Pedals were limited partly because EarthQuaker was building them with hard-to-source NOS (new-old-stock) components; for the HalfLife, EQD founder Jamie Stillman "has completely reworked the circuit using readily available modern parts"2. MusicRadar notes Stillman "has even made a few refinements to the pedal" beyond the parts swap4.
The size is the other headline: MusicRadar reports the HalfLife is "approximately half the size of the Life Pedals"4. It is also the standard-issue successor to the extremely limited-edition Sunn O))) HalfLife Fer MMXXV5. Gearnews notes the standard HalfLife's price point is lower than the larger-format Life V3 model2.
What reviewers said
Guitar World's review rates the HalfLife's sound at four and a half stars, concluding that it "delivers a thundering octave/distortion experience tailor-made for doom architects and those who poke around in the lower registers"5. Guitar Pedal X's Stefan Karlsson, who names the V2 as his favorite Life Pedal edition and notes the HalfLife carries the same controls, calls it "very much a known quantity and much copied," and considers $259 "a fair price"3.
Videos
B's Music Shop
Guitar Interactive Magazine
Flipside Music
Questions
How much current does the EarthQuaker HalfLife draw?
The HalfLife draws 15 mA, according to EarthQuaker Devices' product page. It runs on a standard 9 volt DC power supply with a 2.1mm negative center barrel, and the maker says not to run it at higher voltages. That draw is low enough that it will not strain most isolated pedalboard power supplies.
Can I use the boost without the octave distortion on the HalfLife?
Yes. The octave distortion and the booster each have their own footswitch, and EarthQuaker Devices says they can be used independently. The right footswitch activates the octave distortion and the left one activates the boost, so you can run the clean boost on its own or stack it after the distortion.
Does the HalfLife have an expression pedal input?
Yes. There is a 1/4 inch Octave Expression jack, and EarthQuaker Devices says you can connect any expression pedal to it to control the analog octave blend. This gives you foot control over how much of the octave-up signal is mixed in while you play.
Where is the EarthQuaker HalfLife made?
Like all EarthQuaker Devices pedals, the HalfLife is made in Akron, Ohio, in the USA. Guitar World's review also lists the pedal's country of manufacture as the USA. It carries EarthQuaker Devices' lifetime warranty.
Sources (9)
- Sunn O))) HalfLife Octave Distortion + Booster, EarthQuaker Devices
- EQD Sunn O))) HalfLife: Compact Doom!, gearnews.com, 2026-06-17
- Guitar Pedal X, Guitar Pedal X, 2026-06-17
- EarthQuaker Devices unveils Sunn O))) HalfLife pedal, MusicRadar, 2026-06-16
- EarthQuaker Devices Sunn O))) HalfLife Octave Distortion & Booster review, Guitar World, 2026-07-29
- EarthQuaker Devices Sunn O))) Life Pedal V3, Delicious Audio, 2024-11-25
- NAMM 2020: Earthquaker Devices Sunn O))) Life Pedal gets (another) limited release, gearnews.com, 2020-01-09
- NAMM 2020 Demo: EarthQuaker Devices and Sunn O)))'s Life Pedal, guitar.com, 2020-01-17
- EarthQuaker Devices Sunn Life Pedal V3 Review, GuitarPlayer (www.guitarplayer.com), 2022-11-15
