ZVEX Vibrophase

SPEED - This control feeds an input on a micro controller that’s pro- grammed to generate a sine wave output to drive an LED over a very wide range of frequencies. It can completely crawl or zip off like a hummingbird. This is the only digital part of the effect. All of the audio path is entirely ana- log. All audio components are devices which existed in the 70s or earlier.

VIBRATO/PHASE - This control adjusts the mix from Vibrato (counter-clockwise) to Phase (clockwise). Phasing occurs when the Vibrato signal coming from the sweeping phase shift networks is blended with some original dry guitar.

FEEDBACK - This control takes the output signal and leaks some of it back into the input of the four phase shifters. In a way it’s like adding more stages, but not really, because feedback of this nature also can cause some whistling, which can add a bit of drama to the sound. Always use this knob tastefully, except when the power of rock compels you. This control can make the VibrophaseTM think it’s more important than your guitar.

HIGH BIAS - This control interacts with the Low Limit control so if you set it and then adjust the Low Limit you may have to come back and set it again. It essentially sets the highest voltage that can be sent to the LED so it determines the high point of the sweep. It’s completely analog so if you’re running off a battery and it’s going flat, your sweep may drop off.

LOW LIMIT - This control interacts with High Bias so if you set it and then adjust the High Bias you may have to come back and set it again. It essentially sets the lowest voltage that is sent to the LED. It can be used in conjunction with the High Bias to keep the sweep range confined to a very vocal (or wah-like) zone that can be very musical. Or you can set these two controls for the widest possible sweep, or for a sweep in the bass range, or a sweep only up in the wispy treble zone.