Random*Source Serge CV-PRO Manual

Serge Audio Mixer
SERGE Audio Mixer
The Serge CV-PRO / MIXER pcb set by Random*Source can be built as either a (single or dual) Voltage Proces-
sor or as an active Audio Mixer with 3 input chanels, where the phase of the first input can be inverted for
phase cancellation effects. This document describes only the Audio Mixer setup.
As the Audio Mixer uses only one half of the main pcb, the areas grayed out in the following picture should
be ignored (left empty):
Please note:
• Orientation of the main pcb: power header is at the bottom (when looking at the module up-
right, e.g. in a rack).
• Circuit contains an interesting diode-based limiter section to prevent the added signals from
ugly clipping. This was presumably intended for use of the module as a CV processor. However,
it can also be used with audio signals - this leads so a fairly strong softening / rounding of the
resulting waveform that affects the sound similar to a slight wavefolding.:
For a "clean" audio mixer leave the jumpers JP1 open to ignore the limiter section.
To experience the effect of the limiter section, install 2 jumpers at JP1 (parallel to the board, i.e.
connecting left and right pins in the photo above).
• Use a nice (dual) op-amp for high fidelity, e.g. a Burr-Brown OPA2134 or Burr-Brown OPA2604.
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