This page describes the operation of the ECS-4 Triggered Switch in full detail.

Check out the summary of the module operation in the user guide sheet first. There is also a video linked to the product page.

Switch architecture

The ECS-4 Triggered Switch module is a quad switch. It has four analog outputs, which are all together connected either to the four “A” inputs, or to the four “B” inputs. The switch can be controlled with the “SELECT” buttons, or with trigger pulses on both channels’ SELECT input jacks.

There is also a trigger (or gate) output jack. Either of the “SELECT” buttons causes a short (10 ms) pulse (+5V) to appear on this output. Likewise all the pulses on the A and B SELECT input jacks will be combined on the single trigger output.

Extending the switch

A second ECS-4 can be connected to the “EXT IN” port in the back of the module. More modules can be chained this way, always connecting the “EXT OUT” port of one to the “EXT IN” of the next one with a cable. Each module needs power separately.

The connected modules act together as a single switch: one channel at a time will be selected as active, and the four CV signals of that channel will be routed to the “leftmost” module’s outputs.

The outputs of the other modules will remain unused. The last selected channel “to the right” of those inputs will be connected to those outputs. That may be useful for some purpose, perhaps for controlling side chains only with certain triggers. Let us know how you used them!


In the back of the module you will find a 6-way dip switch. The switches control options as follows:

Option switch numberDescription
1Momentary SELECT buttons
2Shorter trigger pulse (1 ms instead of 10 ms)
3Shorter trigger gap (0.1 ms instead of 1 ms)
4Buttons override SELECT input jacks
5Disable external led override
6Add delay to trigger output

The function of these switches is discussed below.

Gates and button triggers

ECS-4 does not really care about what kind of pulses it receives in the SELECT inputs. It will pass all of them through to the trigger output as-is. If the pulses are long, as in gates, the output will repeat the gates with the same length.

The SELECT buttons normally send out short pulses on the trigger output. The default length of these pulses is 10 ms, which can be reduced with the option switch 2 to 1 ms.

The option switch 1 makes the buttons momentary, in such a way that they output gates instead of trigger pulses. As long as a button is held pressed, the output is active.

Gaps added in output

It may happen that multiple SELECT inputs are active at the same time. For example, two gates on the SELECT input jacks may overlap. Or you may press one of the SELECT buttons while the input gate is active.

In this situation a short gap is output on the trigger output first, followed by the active trigger/gate input or button press pulse. The length of the gap is normally 1 ms, and it can be made shorter with the option switch 3.

The purpose of this gap is to avoid coalescing the individual input triggers. If the trigger output is connected to a drum machine, this guarantees that every new SELECT signal or button press will trigger the drum machine again.

If you are using the ECS-4 module for switching between waveforms at audio rate, try to avoid overlapping the SELECT input gates. If any gaps are inserted, it will likely mess up the audio rate modulation timing, and cause a fuzzy sound instead of what you intended.

The output always tracks the last input. That is to say that if you send two gates on the inputs, second one following the first one, and if the second one ends earlier than the first one, the output will track the second gate and go to zero, even if the first gate is still active.

Likewise if you send a gate on a SELECT input, and press the SELECT button of the same channel, the button will cause a pulse to be sent out on the trigger output, after which the output goes to zero, even if the gate is still active.

The option switch 4 changes the behavior of SELECT buttons to override other gates. With this option enabled, as long as you keep the button pressed, any signals on the select input jacks will have no effect.

Output delay

Occasionally it happens that a module does not respond all so well to CV changes just before a trigger/gate. Enabling option switch 6 adds a delay to all triggers. The length of the delay is the same as one gap between triggers. The analog CV switch is not affected by the delay, causing the CVs to change earlier than the trigger output activates.

Obviously this is a workaround and you could try to work with the designers of the other modules to improve they process CV inputs.

Pitch cv output

ECS-4 is designed as a precision switch, so that if you turn the attenuators all the way open (clockwise), the CV outputs track the inputs very closely. Melodic pitch CVs will then remain in tune when going through the switch.

Audio or trigger switching

Since the switch is analog, it passes audio as well as CV signals. Here’s a demo of switching signals before/after filters.