Nekyia Circuits - Sigil

Compact analog function generator with voltage-controlled slopes and a switchable cycling core.

Sigil is a fully analog function generator in 4hp. It covers envelopes, LFOs, basic oscillation, and slew limiting without trying to be a Swiss army knife. It focuses on the essentials and executes them cleanly.

Rise and Fall are both voltage controlled, so you can move from tight, percussive shapes to long evolving curves under CV. The Shape control morphs continuously from exponential through linear to logarithmic. It affects both stages at once, which keeps the interface simple but has a strong impact on character. Short exponential attacks snap. Logarithmic falls feel natural and weighted. When cycling, that same control reshapes your LFO waveform in a very direct way.

Engage Cycle and the envelope becomes a modulation source or audio-rate oscillator. The Cycle function is voltage controllable and works as a toggle. Send a trigger and it flips state. This makes rhythmic modulation easy. Use it for ratcheting envelopes, gated wobble, or clocked bursts of movement. Pair it with a divider or sequential switch and it starts to feel alive without adding complexity.

A rear jumper switches the input between Trigger and Slew mode. In Slew, it processes gates, stepped CV, or even audio. That turns it into a compact portamento tool, transient shaper, or basic wave smoother. The output attenuverter spans a full bipolar range, so you can scale and invert modulation without reaching for another module. The End of Cycle output makes chaining envelopes or building rhythmic structures straightforward.

It handles everyday duties with no fuss. VCAs, filter sweeps, pitch glide, modulation duties in small cases. The toggleable cycle and morphing slopes give it enough edge to stay interesting in performance. In a compact system, it earns its space.