Three-oscillator Atari Punk Console drone voice with OLED, LFO and chaos modulation

BIGZUN ADVANCED APC — 3-Oscillator Atari Punk Console | Eurorack Synth Voice | 8HP. Part of the Timewind Project.

Meet Advanced APC — a hand-built, three-oscillator Atari Punk Console for your Eurorack system. It's a digital adaptation of an analog module: inspired by the classic "Stepped Tone Generator" circuit made famous by APC noise toys, but rebuilt from the ground up on a stable digital core and pushed into genuinely chaotic, self-modulating territory. You get the raw, punchy, unpredictable character of classic 555-based noise circuits, plus full digital control over pitch, modulation and chaos depth — repeatable, tunable, and never drifting out of calibration.

NOT JUST THREE OSCILLATORS MIXED TOGETHER

OSC1 is the master oscillator, always running freely. OSC2 only runs while OSC1 is HIGH — exactly like the RESET pin of the second 555 timer in the original stepped-tone circuits. OSC3 only runs while the already-gated OSC2 is HIGH, continuing the cascade. Every rising edge of OSC3 hard-syncs OSC1, feeding back into the very first oscillator. The three voices constantly interact, gate, and re-trigger each other — producing a shifting, self-modulating rhythm that never quite repeats.

MODULATION: LFO, CHAOS, OR EXTERNAL CV

• LFO mode — each oscillator gets its own LFO; modulation depth 0–200% with TRANSPOSE UP/DOWN.
• CHAOS mode — at randomized intervals each oscillator jumps to a new random pitch or glides there at a random speed.
• CV IN — an external CV or audio signal takes over modulation of all three oscillators, overriding the internal LFO/Chaos engine.

OLED DISPLAY & MENU

A black-and-white OLED shows live oscillator frequencies, gate states, modulation source and depth. The settings menu covers LFO MIN/MAX speed, CHAOS MIN/MAX retrigger interval, CV IN sensitivity, factory reset and firmware version. All settings are saved across power cycles.

INPUT & OUTPUTS

• CV IN — external CV or audio to take over modulation
• OSC1 OUT, OSC2 OUT — dedicated oscillator outputs
• MIX OUT — the full mixed signal of all three oscillators

SPECS

• Format: Eurorack, 8HP
• Frequency range: approx. 20 Hz – 3 kHz per oscillator
• Display: black & white OLED
• Power: standard Eurorack ±12V

Every unit is built and tested by hand.

More info: https://bigzun.com/modules/advanced-apc.html

https://bigzun.com/modules/advanced-apc.html