Audio/CV Interface

The Expert Sleepers ES-1 Audio/CV Interface is a Eurorack module designed for use with software such as Expert Sleepers Silent Way. It connects to an audio interface using standard 1/4" jack (balanced or unbalanced) or DB25 (aka DSub) connectors, and outputs CVs to your analogue synths/effects on standard 3.5mm jacks. When used with the Silent Way AC Encoder software, there is no requirement for the audio interface to be DC-coupled.

The ES-1 offers the following advantages over directly connecting an audio interface to analogue gear for CV control:

• No requirement for the interface to be DC-coupled.
• No need for special cables (e.g. TRS to TS 'floating ring' cables).
• No danger of damage to the interface - the ES-1's inputs are completely standard balanced audio inputs.
• Much greater output voltage range - up to 9x more than directly connecting a DC-coupled interface via a 'floating ring' cable.

Specifications
There are two standard configurations of the ES-1:

• Jack inputs - the eight inputs are presented on 1/4" jack sockets, which will accept balanced or unbalanced jack leads. The front panel is 12HP wide.
• DB25 input - the eight inputs are presented on a single (Tascam TA88 standard) DB25 socket. The front panel is 8HP wide.

In both cases the module is 70mm deep. The front panel is drilled for both Doepfer and Analogue Systems mounting holes (using a 'slot' rather than a single round hole). The power connector is a Doepfer standard 16 way IDC, with -12V at the bottom edge of the board.

The unit consists of 8 identical channels. Each channel consists of

• A balanced input stage, capable of accepting balanced or unbalanced inputs. Note that for audio interfaces with differential balanced outputs (e.g. the MOTU Ultralite series) this immediately gives you double the voltage range of using a direct DC connection from the interface.
• An optional rectifier circuit, for use when the audio interface is not DC-coupled. A jumper on the PCB connects or disconnects the rectifier.
• An output amplifier and DC offset circuit. This has a gain range of approximately 1x to 4.5x. The DC offset is adjustable, to centre the output of the rectifier circuit around 0V (if desired).

Customisation
The ES-1 unit will be made available without a panel, for those that wish to mount it according to their own designs (for example, it might be convenient to route the inputs, especially the DB25 connector, to the rear of a modular synth case) or in non-Eurorack cases.

The circuit will work unmodified with ±15V supplies.

Pricing and Availability:
The first ES-1 units are expected to be available towards the end of June (2010), though most are already spoken for.
DB25 inputs £100
Jack inputs £120
Module only (no panel or input connectors) £85

More information:

• expertsleepers.co.uk

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