Serge Audio InterfaceSerge Audio InterfaceSerge AudiointerfaceSerge Audio Interface

Audio Interface

The Serge Audio Interface 4x4 module comprises (from left to right) the Audio Interface, an Equal Power X-Fader with balanced Output and a CV-Processor. The Audio Interface section on the left side contains:

  • Preamp Section
  • Compressor Section with Sidechain input
  • VCA section with Envelope Detector (RMS) and 2 variable Gates.


Brings external signals (dynamic mic, Guitar or other instruments) to the Serge Audio level of 5Vpp. The LED lights up when the signal reaches (or exceeds) 5Vpp.

The Preamp has two inputs, one line level input (mono minijack) with a fixed amplification of approx. x8 and one TRS balanced input (6,35mm TRS) with up to +60dB.


The compressor reduces the dynamic range of the incoming audio signal. Its knob continuously adjusts gain, threshold and compression ratio. It works best with 5Vpp signals.

The internal RMS detector derives an envelope control voltage from the input signal, which is available at the ENV OUT. Note: When SIDE CHAIN is activated the enevlope is derived from the side chain signal!


This high quality audio VCA is controlled by the GATED OUT CV (see below), but offers an additional CV input for external control.

Envelope Detector / Gates

ENV OUT (grey line) provides a control voltage reflecting the envelope of a signal running through the compressor (using an RMS envelope detector).

GATED OUT (blue line) controls the VCA. It is based on this envelope signal (CV), but two additional gates are applied that can be used hard limit the CV signal. The UPPER THRESHOLD knob works as limiter (or volume control) and prevents the CV signal from exceeding the threshold. The LOW THRESHOLD knob kills the envelope (i.e. sets it to 0V) as long as it is below the theshold. This can be used like a noise gate in combination with the VCA.

Some details:

  • New Design
  • Highend preamp
  • Single-knob compressor
  • Highend VCA
  • RMS envelope detector
  • 2 level gates
  • XFader with balanced out
  • 4x4 format (4U - this is not Eurorack!)
  • Power consumption: up to 170mA @ +12V, 140mA @ -12V
  • fits in a superslim boat

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