Stereo Effect Pedal (v1) User Guide


This user guide covers the following pedals:

  • Wet™ Stereo Reverb v1
  • Chroma™ Stereo Chorus v1
  • Echelon™ Stereo Echo v1
  • Slate™ Stereo Effect v1

Thank you for purchasing a Stereo Effect Pedal. We really mean it. We value that you have placed your trust in our product, often based solely on what you see and hear on the internet. We hope to earn that trust by delivering a quality product that inspires you to make better music.

You may be wondering why all the Stereo Pedals share the same User Guide. These pedals share the same hardware platform and actually have many common features. You may also use Expanse Software to transform the functionality of any Stereo Pedal into any other Stereo Pedal, simply by changing its firmware (internal program).

We do not ship paper User Guides with our products. We feel this wastes paper, when the same information is available here. Also, we update this User Guide from time to time and want you to have the most current version.

Warning: This product contains parts that are sensitive to electro-static discharge (ESD). Removing the bottom cover may expose these parts to ESD, which can result in permanent damage and voids the warranty. For this reason, we strongly advise you not to remove the bottom cover or otherwise disassemble the pedal.



The power jack accepts a standard (5.5 mm OD x 2.1 mm ID) center-negative pedal power adapter (not included). The power adapter must be between 9 V and 12V and capable of supplying 100 mA or more. See this page for a list of recommended adapters.

If you are using a daisy-chain cable to power multiple pedals, the total of all the pedals' current (mA) ratings should be less than the current rating of the adapter.


The input jacks accept input directly from your instrument or amplifier effects loop output. The very high-impedance inputs will not present any significant tone-changing load to the signals that drive them.

The input jacks are capable of accepting several combinations of inputs:

  • Input 1 only will accept a mono input—direct from your instrument, another pedal or instrument-level effects loop.
  • Both Inputs 1 & 2 will accept a stereo input—from another stereo pedal or instrument-level effects loop.
  • Input 2 only will accept a stereo TRS input when Input 1 is unplugged.


The output jacks provide output to another effects pedal, amplifier input or effects loop input. This low-impedance buffered outputs are 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.

The output jacks are also capable of several combinations independently of the input jacks:

  • Output 1 only will supply a mono output to your amp, another pedal, or instrument-level effects loop. Stereo inputs will be summed to Output 1 if Output 2 is unplugged.
  • Both Outputs 1 & 2 will supply a stereo output to a stereo amp, pedal or instrument-level effects loop. Using both outputs will create a stereo signal from a mono input.
  • Output 2 only will supply a stereo TRS output when Output 1 is unplugged.

Since the input and output connection are independent, you may—for example—plug in a mono input with stereo outputs or stereo inputs with a stereo TRS output.

Mono Effect on Stereo Outputs

If you wish for the stereo outputs to have identical (mono) effect signals, reprogram your pedal using Expanse Software and select the Menu → Force Mono option. This is useful for

  • driving a mono output to two different places: for example, one to an amp and the other direct to a mixing console
  • place a mono effect on a stereo input signal: for example, a mono delay after a stereo chorus

Wet-Only Signal with Mono In/Out

The pedal can be hacked to drive a wet-only (i.e., "dry kill") signal output for a mono signal:

  • In Expanse Software, select Menu→Force Mono.
  • Select your preferred effect and reprogram the pedal.
  • Plug the mono input into Input 2. Do not plug into Input 1.
  • Plug the mono output into Output 1.
  • Insert a dummy plug into Output 2.
  • The Mix control will function as effect level. For a parallel loop, turn this to maximum.

Expression Inputs

The Expression Inputs may be used individually or simultaneously.

Each Expression Input controls the function of the knob nearest to it. When the Expression Input is plugged in, the knob determines the maximum range for the expression pedal. The minimum range is typically set on the expression pedal itself (except for the Moog EP-2, whose knob controls the maximum).

Each Expression Input accepts a 3.5mm TRS (tip-ring-sleeve) plug. Most expression pedals (treadles) have a 1/4" (6.35mm) TRS plug, so you will need an adapter cable. Any standard 1/4"-to-3.5mm TRS adapter cable will work, but we offer an Expression Input Adapter Cable specifically designed for this purpose. Using this adapter, the Expression Inputs have been tested to work with following treadles:

  • Roland EV-5
  • M-Audio EX-P
  • Mission Engineering EP-1 (requires a 1/4" TRS cable and does not have a control for the minimum value)
  • Moog EP-2 (does not have a control for the minimum value)

(Echelon Echo only) The µTap Tempo pedal plugs into the Expression Input for the Time knob. Only the µTap will work with the Echelon as a tap tempo controller.


USB Jack

The USB Jack is used with Expanse Software and accepts a standard mini-B USB cable.


Mix Knob

The Mix knob controls the effect level. Full counter-clockwise is 100% dry, while full clockwise is maximum effect level. The maximum effect level is approximately equal to the level of the dry signal. The level of the dry signal is always unity (it does not change with the Mix knob).

Depth Knob (Wet Reverb only)

The Depth knob controls the length of the reverb tail, or in other words, the size of the room.

Width Knob (Chroma Chorus only)

The Width knob controls the amount of pitch transposition.

Time Knob (Echelon Echo only)

The Time knob controls the delay time. Due to tolerance variations, the marks around the knob are approximate.

Without the µTap Tempo pedal, the delay time is set directly using the knob. The marks around the knob indicate the time in fractions of 1 second:

  • 1 = 1 second, or 1000 ms
  • 3/4 = 750 ms
  • 1/2 = 500 ms
  • 1/3 = 333 ms
  • 1/4 = 250 ms
  • 1/6 = 167 ms
  • any other position to achieve your desired delay time

When using the µTap Tempo pedal, the marks around the Time knob indicate the time in fractions of the tapped (quarter-note) tempo:

  • 1 = quarter note
  • 3/4 = dotted 8th note
  • 1/2 = 8th note
  • 1/3 = 8th-note triplet
  • 1/4 = 16th note
  • 1/6 = 16th-note triplet

Δ Knob (may change via Expanse Software)

  • Wet™: reverb tone
  • Chroma™: chorus signal regeneration or tone
  • Echelon™: echo repeats

Foot Switch

The foot switch bypasses the effect and is equivalent to turning the Mix knob to zero. The bypass is buffered, which eliminates the tone change that can be caused by some bypassing schemes.

The LED lights when the effect is active.

Bypassing the effect does not significantly change the power consumption, as it does not turn off power to the pedal.

(Wet Reverb only) Your pedal may be updated using Expanse Software to select between trails or normal bypass. Trails bypass allows the reverb to "trail" off naturally after bypassing the effect.

Effect Placement

Delay-based effects such as chorus, delay and reverb work best when placed at the end of the signal chain. The preferred ordering is (other pedals)→chorus→delay→reverb→amplifier. If you are using the distortion in your amplifier, these pedals should be placed in the effects loop.

Signal Flow & Routing

This simplified diagram illustrates the signal flow through the Stereo Pedal:

  • Both Inputs and Outputs are buffered.
  • When Input 2 is unplugged, both input buffers are driven by Input 1.
  • When Input 2 is plugged in, the shunt is lifted and stereo inputs driven discretely.
  • If Input 2 is not driven with signal, it should be unplugged.
  • When Output 2 is unplugged, both output buffers passively sum to Output 1. In this case, the effect processor knows to drive a mono signal to both of its outputs.
  • When Output 2 is plugged in, the shunt is lifted and stereo outputs are driven discretely.
  • If Output 2 is not used, it should be unplugged. Otherwise, you will only hear half of a stereo output, which is not the same as a mono output.
  • For clarity, the TRS routing for Input 2 and Output 2 is not shown. If the TRS (#2) Input is used, Input 1 must be unplugged. Likewise, if the TRS (#2) Output is used, Output 1 must be unplugged.
  • As shown by the diagram, the two wet signals are not independent. Therefore, the Stereo Pedal cannot be used as two discrete mono pedals. Note that a dual discrete mono configuration is undesirable, because it fails to create a stereo output from a hard-panned stereo input.


Nominal Input Level -10 dBu, instrument level
Max Input Level 6 Vpk-pk
Input Impedance 2.0 MΩ stereo, 1.0 MΩ mono
Output Impedance 1 kΩ stereo, 500Ω mono
Gain 0 dB, 0% Mix vs. bypass
Frequency Response 20 Hz—20k Hz, +0.0/-0.5 dB
(dry signal or bypassed)
Total Harmonic Distortion + Noise 0.003% typical, 22Hz—22k Hz
(dry signal or bypassed, input: 1.0 VRMS @ 1k Hz)
Signal-to-Noise Ratio 105 dB typical, A-weighted, 22 Hz—22k Hz
(knobs @ 50%, 2 VRMS reference)
Power Adapter Input 9-12 V DC, 100 mA, plug center-negative, 5.5 mm OD x 2.1 mm ID
Dimensions 2.8" W, 4.6" L, 1.6" H / 72 mm W, 116 mm L, 49 mm H
Weight 8.0 oz (220 g)

*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.