There are two channels, each controlled by three potentiometers: GAIN (2), RES (3), FREQ (4) and sidechained by CENTER (5). Both channels have the same topology. Inputs •| and |• are fed into each channel’s gain stage and then passed to their filters. The input signal level can be adjusted by setting the GAIN which can either attenuate or amplify a signal x20. Note that the amplification affects the filter’s behaviour—high GAIN disrupts self-oscillation, conjuring PLL-esque harmonics and other sound design artefacts. FREQ and RES are used to manipulate individual filter’s cutoff frequency and resonance. Each channel has a side-mounted switch (6) for selecting low-pass or band-pass filtering. Touch the golden touch pads (1) to manually route the flow of audio and control voltages.

SIDECHAIN – Left channel’s (•I, •O) post-gain signal is filtered and fed into an envelope follower. Envelopes polarity and amplitude are adjusted by using CENTER. The adjusted envelope is then mixed in the right
(|•, O•) channel’s FREQ parameter. Left half of the CENTER causes the filter to “duck” and the right half produces a gating response. In the middle position, the sidechain effect is inactive.

TOPOLOGIES

FEEDBACK – Connect the •O and I• sockets with a jack cable and use O• as the main output. Leave •I unconnected as it’s normalised to O• by default.
Alternatively, using stereo cables and a headphone splitter adapter enables the use of •O as output with dramatic stereo field dynamics.

SERIAL – Connect the audio source to I• and use the •O as output.
Input signals are processed through subsequent channels as •I is normalised to O•. This mode enables the so-called twin peak and auto-filtering.

PARALLEL – Connect a stereo audio source into •I or two mono sources to •I and I•.
Left and right signals are split into separate channels, processed and output as stereo signal via •O or as mono on both outputs.