Audio Interface II Manual


The Audio Interface II is designed to interface your modular system with line-level equipment using balanced 1/4″ TRS cables.


See the Module Installation Guide for instructions on installing the module in your Eurorack modular system.

Front Panel



    These knobs set the gain of the signal coming in to the modular via the BAL IN L/R jacks. The knob range is from -∞ (no signal) to +6 dB. The signal levels are indicated on the meters above the OUT L/R jacks.
    These knobs set the gain of the signal leaving the modular via the BAL OUT L/R jacks. The knob range is from -∞ (no signal) to +6 dB. The signal levels are indicated on the meters above the IN L/R jacks.

Inputs & Outputs

  1. OUT L/R
    These jacks are the modular level outputs of the signals coming in to the system via the corresponding channel of the BAL IN L/R jacks. The signals are boosted to modular levels according to the INPUT GAIN knobs.
  2. BAL IN L/R
    These jacks bring signals in to your modular system from the outside world to their corresponding OUT L/R jacks. Connect a 1/4″ balanced TRS cable. from the output of your other synthesizers, effects pedals, audio interfaces, etc. to these jacks.
  3. IN L/R
    These jacks are the modular level inputs that send your modular’s audio to the outside world. A modular audio signal connected to these jacks will appear at line level on the corresponding BAL OUT jacks, with gain controlled by the OUTPUT GAIN knobs.
  4. BAL OUT L/R
    These jacks carry signals from your modular to your other audio equipment. Use a 1/4″ balanced TRS cable to connect each one to an input of an effects pedal, audio interface, tape recorder, etc.


The Audio Interface II is divided into two halves that function independently. The left side is the Input side which takes signals from line level sources such as sound cards, synthesizers, or mixers, and converts them to modular level. The right side is the Output side and takes signals from modular level sources and converts them to line level for sending to a sound card, mixer, or other outboard processor. The diagram below illustrates a typical configuration for processing audio from a synthesizer through the modular system and then passing the output to a mixer:

Input From and External Source

To take input from an external sound source and process it through the modular system first connect the output of your external device to either the L or R BAL IN jack using a 1/4″ TRS cable. If you are using a stereo source you may wish to connect to both the L and R BAL IN jacks. You can also connect two totally different devices, one to L and the other to R.

The output from each channel of the BAL IN jacks will appear at the corresponding L or R modular level output directly above the BAL IN jacks. You can adjust each input’s level using the INPUT GAIN knobs. Ideally the knobs are set such that the loudest inputs cause the input VU meters to go as high as possible without the red CLIP LED lighting up.

Output to an External Destination