Expert Sleepers ES-4 (Sneak Preview)

This is a preview of the Expert Sleepers ES-4, a Eurorack format module that converts a standard S/PDIF input to five channels of control voltage.

Two of the five channels are calibrated to provide over 5 octaves of 1V/octave pitch CV. The remaining three channels are general purpose outputs (for use as e.g. gates, envelopes, LFOs) and each have a nominal range of 0-10V or ±5V (user selectable).

Since S/PDIF is a stereo-only format, the encoding of the five channels on to two is handled by software to be provided as part of Expert Sleepers Silent Way.

The ES-4 will connect to any audio device using the S/PDIF standard. This includes the digital audio output provided as standard on all recent Macs.

The ES-4 Gate Expander is a Eurorack module which works in tandem with the ES-4 to offer 8 on/off outputs for use as gates, triggers, clocks etc.

Up to five ES-4 Gate Expanders can be attached to one ES-4 – one per ES-4 channel. (The 8 outputs of the Gate Expander reflect the 8 bits of CV information passed to the ES-4?s DACs.) Therefore you can combine the modules to create a system with up to 40 independent gate outputs – all driven from a single S/PDIF connection.


  • Panel width: 8HP.
  • Module depth: 51mm.
  • Digital input: coaxial S/PDIF.
  • Digital output: coaxial S/PDIF.
  • Analogue outputs: 5x 3.5mm jacks, DC-coupled.
  • Output voltages
    • Channels 1-2: 0-5.3V (when trimmed for 1V/octave response).
    • Channels 3-5: 0-10V or ±5V (jumper selectable per channel).
  • D/A conversion: 8 bit, using high precision Analog Devices DACs.
  • Indicators: LED for S/PDIF sync lock; 2 LEDs per channel on channels 3-5 indicate output voltage (+ve/-ve).
  • Expansion
    • 5 headers for connecting ES-4 Gate Expander modules (see below).
    • Digital audio I/O header (I2S format) for future expansion.

    Pricing and availability are TBA. Details at the Expert Sleepers site.


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