ChromaChorus Pedal (Mono, v1) User Guide

Thank you for purchasing the ChromaChorus™ Pedal. To reduce waste and provide you with the most up-to-date information, we do not include paper manuals with our products.


Power Jack

The power jack accepts a 9V DC center-negative input capable of supplying at least 50 mA. Plugging into the power jack disconnects the battery.

Input Jack

The mono input jack accepts input directly from your instrument or amplifier effects loop output. Unplugging the input jack when not in use will extend the battery life.

Output Jack

The mono output jack provides output to another effects pedal, amplifier input, or effects loop input. This low-impedance output is capable of driving long cables without a change in tone. If plugging into the input of your amp, you should use the low impedance (Lo-Z) input if available.


Mix Knob

The mix knob controls the chorus level. Full counter-clockwise is dry (no chorus). Full clockwise is 100% chorus signal for parallel effects loops.

Width Knob

The width knob controls the amount of pitch transposition. Higher width settings also add feedback for extra richness.

The following diagram illustrates the range of the mix and width knobs:


The LED lights when the effect is active. The LED will become increasingly dim as the battery voltage drops. If the LED fails to illuminate, please check your battery or power supply.

Foot Switch

The foot switch bypasses the effect.


The type of bypass is selectable via an internal switch as either buffered (B) or unbuffered (UB). The switch is located inside the battery bay under the PCB, below the letters "UB" and "B".

Buffered bypass is preferred for most applications. There are two exceptions:

  • When used in front of your amp with a buffer or buffered-bypass pedal first in the signal chain, or have active pickups/electronics in your guitar
  • When used in a buffered effects loop

Note that when the effect is engaged, the signal is always buffered. This means the unbuffered bypass setting can result in a change in tone, because you (a) loose the buffering of the signal, and (b) are adding the load of additional cable after the effect. This is why we do not recommend the unbuffered bypass without an external buffer or active pickup/electronics in your guitar.

In the buffered bypass setting, the signal passes through only one buffer stage. This minimizes any added noise while the pedal is bypassed.

The unbuffered bypass setting is not "true" bypass; it is what is sometimes called a "hardwire" bypass with a 1.1 megaohm input impedance. This is a very small load and is comparable to a high-quality tube amplifier input.


The battery compartment accepts a 9V (PP3) battery. The ChromaChorus will work with any 9V battery, although an alkaline or Li-Ion rechargeable is recommended for maximum battery life

Unplug the input jack or plug in the power jack to disconnect the battery. When the battery gets low, the LED will get dim or not light. This means it's time to replace the battery.

Battery Compartment

To access the battery compartment, use a Phillips screwdriver to remove the 4 screws that attach the bottom cover. Use care when opening the bottom of the pedal: do not touch the circuit board, as electro-static discharge can kill your pedal.

When replacing the battery, do not pull on the wires that attaches the battery snap to the circuit board. The battery fits best in an upside-down position, with the battery snap wires leading from the battery toward the inside of the pedal.


Nominal Input Level -10 dBV, instrument level
Max Input Level 6 Vpk-pk
 Input Impedance 1.1 MΩ
Output Impedance 470 Ω
Gain 0 +/-0.25 dB, 0% Mix vs. bypass
Frequency Response unbuffered bypass: 20Hz—20kHz, +/-0.1dB
buffered bypass: 20Hz—20kHz, +0.1dB, -0.5dB
enabled, dry signal: 20Hz—20kHz, +0.1dB, -0.5dB
Total Harmonic Distortion
(measured 22Hz—22kHz,
input: 1 VRMS, 1 kHz)
unbuffered bypass: < 0.0005%
buffered bypass: < 0.008%
enabled, dry signal: < 0.008%
Signal-to-Noise Ratio
(22Hz—22kHz, unweighted,
2 VRMS reference)
unbuffered bypass: > 120dB
buffered bypass: 116dB typical
enabled, dry signal: 107dB typical
enabled, knobs at 50%: 99dB typical
Power Adapter Input 9-12 V DC, 30 mA, center negative, 5.5 mm OD x 2.1 mm ID
Battery 9 V PP3
Battery Life 12-14 hours, alkaline (typical)
Dimensions 2.8" W, 4.5" L, 1.85"H / 71 mm W, 115 mm L, 47 mm H
Weight 7 oz (200 g), without battery

*Specifications subject to change without notice.

This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.