The Strymon Zelzah Is a 4-Phaser-In-One Marvel

Leave it to Strymon to create one of the most versatile phasers you'll ever use.

The minds behind the Iridum, Big Sky, Flint, and more revolutionary digital effects have brought their attention to the phaser, and the results are predictably incredible.

The Zelzah is a stereo phaser with lots of extras built in. As Strymon explains: "Our goal was to capture the rich phasing sounds that were introduced in the 1970s that work so beautifully with electric guitar and electric piano. In addition to providing the best possible version of the vintage phaser sounds we grew up with, we also wanted to expand the sonic possibilities in a way that was unique and unexpected for a phaser."

Strymon Zelzah

To achieve this breadth of possibilities, the Zelzah has two sides, each containing two separate phasers. On one side contains two four-stage phasers, which offer classic, barber (continuous upward or downward), or envelope-controlled phase tones. On the other are two six-stage phasers built around an all-pass filter they've modified to expand the time response, delaying or quickening how the filter interacts with the incoming signal.

Strymon's Zelzah introduction video.

You can use either side of the Zelzah independently or use them together in three different ways: running in series, running in parallel, or split them to hear one on a left channel and the other on the right.

Full features, according to Strymon, include:


  • SPEED - Adjusts the LFO rate of the 4-Stage phaser.
  • SWEEP - Selects the style of the 4-Stage phaser. Classic: traditional rising and falling LFO voicings that change in character as the DEPTH knob is adjusted. Barber: rising or falling LFO. Polarity is adjusted via a live edit function. Env: touch sensitive envelope phasing effect with range set by the SPEED knob and sensitivity set by the DEPTH knob.
  • MIX - Adjusts the balance of the dry signal and the phase- shifted signal from mild phasing at min to 100% wet at max.
  • Strongest phasing effect occurs with knob set at 12 o’clock (50/50 mix).
  • DEPTH - Adjusts the LFO range. A deeper phasing effect is achieved as the knob is turned clockwise.
  • 4-STAGE ON - Engages the 4-Stage phaser circuit, independent of the 6-Stage phaser.
  • Red ON LED indicates that the 4-Stage phaser is engaged. The LED pulses in time with the selected SPEED when engaged.


  • SPEED - Adjusts the LFO rate of the 6-Stage phaser.
  • RESONANCE - Selects from three settings of regeneration that add color and intensity. Off: smooth response. Mild: enhanced frequency peaks. Strong: prominent frequency peaks.
  • VOICE - Sweeps smoothly from pure phaser voicings on the left to flanger tones past 12 o’clock and chorus tones on the right.
  • DEPTH - Adjusts the LFO range. Higher settings result in more dramatic phase and/or time modulations as set by the VOICE knob.
  • 6-STAGE ON - Engages the 6-Stage phaser circuit, independent of the 4-Stage phaser. Red ON LED indicates that the 6-Stage phaser is engaged. The LED pulses in time with the selected SPEED when engaged.
  • NOTE: When both 4-Stage and 6-Stage are bypassed, an electromechanical relay is activated for True Bypass.


  • AUDIO INPUT SELECTOR - Selects input/output configuration modes. MONO : Use with a mono input signal such as a guitar. Output stereo, or mono if only OUT L is used. STEREO : Use with a stereo input signal. Output is stereo.
  • IN - High impedance ultra low-noise discrete Class A JFET preamp input. Use a TRS stereo adapter/cable for stereo input.
  • OUT L and OUT R - Audio outputs. Use only OUT L for mono output.
  • USB - Used for MIDI control as well as for performing firmware updates.
  • 9V DC - Use the included power supply or an adapter with the following rating: 9VDC center negative, 300mA minimum.
  • EXP/MIDI - Multifunction communication jack for external control of Zelzah’s features and functions. Can be set to operate in one of the following modes. Expression Pedal mode - Allows continuous control over any of the knobs in any direction with a standard TRS expression pedal. Favorite mode - Allows you to recall a Favorite setting using a Strymon MiniSwitch. Tap mode - Allows you to control the SPEED of the 6-stage phaser with TAP tempo using a Strymon MiniSwitch. MIDI mode - Allows for the selection of up to three presets using a Strymon MultiSwitch Plus or for full MIDI functionality including access to 300 presets by sending MIDI Program Change messages via 1/4” TRS MIDI connection.

Order your Zelzah on Reverb now.

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