Alexander Pedals Equilibrium - Tremolo / Harmonic Vibrato



Alexander Pedals

The Equilibrium returns us to a simpler time, when cars had fins like rocket ships, and the electric guitar was in its infancy.  The earliest guitar amps had very simple circuits, and the Equilibrium harkens back to the modulation effects from the dawn of amplification.


  • Rate - adjusts the rate of modulation from a slow pulse to a rapid flutter.

  • Depth - controls the amount of modulation from barely perceptible to seasick.

  • Shape - counter-clockwise for a rounded sine wave, clockwise for an abrupt square wave.

  • Mix - adjusts between the dry signal and the modulated signal.  For traditional style tremolo the Mix knob should be fully clockwise.

Mode Toggle:

  • Tremolo - this position dials in a traditional amplifier-style tremolo.  The Equilibrium tremolo is based on the amplifier bias circuits from the earliest tube amps.  The Shape control morphs the tremolo from a very soft and smooth sound to a much harder burp-burp modulation.  The Depth knob adds a carefully selected amount of gain to compensate for the volume drop of a traditional tremolo.

  • Harmonic - based on the vibrato circuits from the early ‘60s piggyback amplifiers, the Harmonic mode splits the signal through two separate filter paths and combines them again for a phasey-sounding warble.  Blend in the dry signal for a more pronounced phaser effect.

  • Vibrato - the final mode is based on the unique frequency modulation effects pioneered by Donald Bonham in the late ‘50s.  In vibrato mode, the Equilibrium actually performs a true frequency vibrato just like Buddy Holly.  Try it with a fast speed and 100% wet mix for the widest vibrato effect.  Here's some trivia for you - the original Bonham modulator is essentially a phase shifter with zero dry signal.  The Equilibrium can add in this dry signal with the Mix knob, and will product a mild phasing tone in Vibrato mode.

Power Supply:

The Equilibrium requires a 9V DC power supply with a 2.1mm pin, center negative.  The Equilibrium is not designed to be powered on supplies higher than 9V and does not use a battery.  The Equilibrium should work fine on a multi-pedal "daisy chain" connector, but if you encounter excessive noise or hum try a separate power supply.

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