Say hello to the Expert Sleepers ES-4 S/PDIF / CV Interface, the latest addition to the company's line of Eurorack modules.

The ES-4 is a nifty new 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 five octaves of 1V / octave pitch CV, while the remaining three channels are general purpose outputs (for use as gates, envelopes, and LFOs, for example). Each channel has a nominal user selectable range of 0-10V or ±5V.

According to the manufacturer, 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 new 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.

Likewise, the ES-4 Gate Expander is a Eurorack module that works in tandem with the ES-4 to offer eight on / off outputs for use as gates, triggers, clocks, and so forth. Up to five ES-4 Gate Expanders can be attached to one ES-4 -- one per ES-4 channel. Just so you know, the eight outputs of the Gate Expander reflect the 8 bits of CV information passed to the ES-4's DACs. With this in mind, you can combine the modules to create a system with up to 40 independent gate outputs, all driven from a single S/PDIF connection.

ES-4 prelimiary specifications:

• Panel width: 8HP
• Module depth: 51 mm
• Digital input: coaxial S/PDIF
• Digital output: coaxial S/PDIF
• Analog outputs: five 3.5 mm 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
• Digital audio I/O header (I2S format) for future expansion

ES-4 Gate Expander preliminary specifications:

• Panel width: 4HP
• Module depth: 24 mm
• Analogue outputs: eight 3.5 mm jacks, DC-coupled
• Output voltages: 0V / 5V or 0V / 12V, selectable via jumper in groups independently for channels 1-4 and 5-8
• Indicators: LED per channel

Expert Sleepers plans on shipping the ES-4 in August, 2011, and pricing will be announced as we get closer to the release date. For more information, visit the Expert Sleepers Web site.