Tunable 3rd-order pingable resonator based on the Gamelan Resonator circuit from Paul DeMarinis’ Pygmy Gamelan (1973).
The circuit was analyzed by Werner & Teboul (AES Convention Paper 10542, 2021) and found to be a completely unique active filter topology, distinct from the Bridged-T and Twin-T designs common in analog drum machines.
When pinged, Tine produces metallic, bell-like ringing tones. The damping control varies the ring time from short percussive thumps to long sustain approaching self-oscillation.
8 HP. Monophonic audio output.
Why it sounds different
Most pingable filters in analog drum machines are 2nd-order (Bridged-T, Twin-T). Tine’s 3rd-order topology produces:
- Steeper spectral rolloff above the resonance (18 dB/oct vs 12 dB/oct)
- A different phase response that shapes the attack character
- Two zeros that create a specific spectral notch pattern
The result is a ring that sounds more “metallic” than a typical 2-pole resonator: closer to struck metal than a filtered impulse.
Damping and amplifier gain
In the original circuit, the ring time is determined by the LM3900 Norton amplifier’s finite voltage gain (approximately 3500x). The circuit is only stable because the amplifier is imperfect: with infinite gain, it would ring forever.
Tine exposes this amplifier gain as the Damping parameter, allowing you to sweep from heavily damped (low gain, short thump) through the natural LM3900 behavior (moderate ring) to near-marginal stability (very long sustain).
Controls
| Control | Range | Default | Function |
|---|---|---|---|
| Freq | -4 to +4 octaves | 0 (C4) | Resonant frequency, log2 scaled |
| Damp | 0-1 | 0.5 | Ring time. Low = short thump, high = long sustain |
| Ping | Momentary | Manual trigger |
Inputs
| Input | Range | Function |
|---|---|---|
| TRIG | Gate/Trigger | Rising edge fires a ping |
| V/Oct | 1V/octave | Pitch CV |
| Damp CV | ±5V | Damping modulation |
Outputs
| Output | Function |
|---|---|
| Out | Monophonic audio output |
VCA mode (anti-click)
Enabled by default (toggle in right-click context menu). When a new ping arrives while the previous ring is still decaying, VCA mode crossfades between them:
- Output envelope fades down over 2.5ms
- Filter state is cleared
- New pulse fires
- Output envelope fades back up over 2.5ms
This eliminates the zero-crossing click that occurs when a new impulse interrupts a decaying oscillation. With VCA mode off, pings fire immediately: raw and clicky, but maximally responsive.
Patch ideas
Metallic Ping Voice: Patch a clock to TRIG, a sequencer to V/Oct. Each clock pulse produces a pitched metallic tone. Adjust Damp for short percussion or sustained bell tones.
Gamelan Bell: Set Freq low (-2 to -3 octaves), Damp high (0.7-0.9). Trigger with an irregular clock or random trigger source. The long, low-pitched ring evokes gamelan percussion.
Damped Drum: Damp very low (0.1-0.2), Freq in the bass range. Short, punchy, percussive. Modulate Damp CV with an envelope for dynamic variation.
Resonant Drone: Damp at maximum (1.0). The filter approaches self-oscillation: even small trigger inputs or noise produce sustained tones. Modulate Freq slowly for evolving pitched drones.
Polyrhythmic Bells: Use multiple Tine instances at different frequencies. Clock each from different divisions of a master clock. Pan them across the stereo field for a gamelan-like ensemble.
Historical context
The Gamelan Resonator was designed by Paul DeMarinis in June-July 1973 for his Pygmy Gamelan installation, part of David Tudor’s Composers Inside Electronics group. Six copies were built, each tuned to a different five-tone scale using whatever resistors and capacitors were available. The circuits played autonomously in gallery settings, pinged by shift registers receiving stray electromagnetic signals from crude antennae.
The circuit’s topology has no documented precedent. A survey by Werner & Teboul of dozens of analog drum circuits, active filter textbooks, and op-amp datasheets found nothing with a similar arrangement.