Half the Size. Just as Heavy.

The Sunn O))) HalfLife™ by EarthQuaker Devices is the most pedalboard-friendly version of the legendary Life Pedal distortion circuit to date. Designed to replicate the core front-end chain used during Sunn O)))’s Life Metal sessions, the HalfLife combines a brutal octave distortion with a devastatingly clean MOSFET booster into one compact, earth-shattering enclosure.

Whether you are pushing a vintage tube amp into overloaded ecstasy or shaping modern doom metal tones, the HalfLife is engineered to clear chasms and shear mountains.

The Amplitude: Crushing Distortion

Modeled after the classic "White Face" distortion unit, the HalfLife's Amplitude section delivers iconic, grinding tone. It features a versatile 3-way clipping switch to perfectly match your rig:

• OpAmp: No diodes. Delivers a full, uncompressed, grinding OpAmp assault at maximum volume.
• Asymmetrical: Two silicon diodes and one LED. Provides a smooth, slightly compressed crunch akin to a driven valve amplifier.
• Symmetrical: Stock double silicon diodes for the classic, tight, and compressed distortion you know and love.

The Octave: Blendable Analog Chaos

Located at the input of the circuit, the HalfLife features an all-discrete, full-wave rectifier analog octave-up. Slowly blend it in via the Octave control, or hook up an expression pedal for wild, hands-free octave swells mid-riff. Push the blend to the max to transform the pedal from a standard distortion into a swelling, raging fuzz. (Note: As an analog effect, the octave is monophonic and tracks best above the 12th fret on your neck pickup).

The Magnitude: Pure MOSFET Boost

The Magnitude section is a 100% clean, high-impedance, all-discrete MOSFET booster designed to blast your preamp tubes. Delivering up to +60dB of gain, it adds virtually zero color to your tone—it simply provides the raw output needed to push your amp into harmonic saturation and feedback overtone bliss.

Independent Switching & Flexi-Switch® Technology

The Octave Distortion and Booster circuits operate independently with their own footswitches. Both utilize EarthQuaker’s proprietary Flexi-Switch® Technology, allowing you to use both traditional latching and momentary switching for precise, stuttering bursts of noise.

Key Features:

• Circuit: Octave Distortion + Clean MOSFET Booster
• Collaboration: Officially licensed by Sunn O)))
• Clipping Modes: 3-way toggle (OpAmp, Asymmetric, Symmetric)
• Octave Control: Blendable analog octave with EXP pedal input
• Switching: Independent footswitches with relay-based true bypass Flexi-Switch® Technology
• Power: Standard 9V DC (15mA current draw)
• Origin: Hand-built in Akron, Ohio, USA

Controls:

• Octave: This blends in the analog octave as you turn it clockwise.
• Distortion: Turn clockwise for more distortion, counterclockwise for less. This provides about +60dB of gain.
• Filter: This is a low pass filter with a frequency response from around 500 Hz to 30 kHz. Turn counterclockwise for more high end, clockwise for less.
• Amplitude: Output volume for the octave distortion side. Clockwise for more hearing loss, counterclockwise for a healthy life in old age.
• Clipping Switch:
  • OpAmp: No diodes to allow for full, grinding Op Amp assault at maximum volume.
  • Asymm: Utilizes two silicon diodes and one LED in an asymmetrical clipping configuration. This delivers a slightly compressed and smooth crunch, similar to a valve amplifier.
  • Symm: This is the stock double silicon diode configuration which provides that classic tone you know and love.
• Magnitude: This is the output volume for the booster. Clockwise to blow up your amp, counterclockwise if you’re a baby. Unity is somewhere right around noon on the dial.
• Right Footswitch: Octave Distortion Activator
• Left Footswitch: Boost Activator
• Octave EXP: Connect any expression pedal to this input to control the analog octave blend. Before inserting the expression pedal, make sure the pedal is powered off.