schlappi-engineering/100-grit
100 Grit
A touch-controlled distortion unit with a low-pass filter, OTA VCA, distortion section, 8 touch points, voltage control over drive, resonance, and frequency, and a plethora of feedback paths for hands-on performance.979
Capabilities 3
Jacks 12 (9 in / 3 out)
| Name | Signal | Voltage | Description |
|---|---|---|---|
| Inputs (9) | |||
| DIST 1 AMP PIN (touch) | mixed | — | Bidirectional touch point connected to the distortion amplifier pin; capacitive loading alone causes effects. Can also pick up radio stations.979 |
| FM1 | cv | — | Frequency modulation input to the filter; normalled to DIST when no cable inserted, applying distortion output as dynamic FM.979 |
| FM2 | cv | — | Exponential voltage control over filter cutoff frequency, roughly scaled to volts per octave but does not track in tune.979 |
| FREQ CV (touch) | cv | — | Touch point connected to the filter frequency CV input; audio-rate FM via this point creates distortion audible at both outputs.979 |
| GAIN CV | cv | ≥0V | CV input for VCA gain; normalled to POLE2 (12dB filter output) when no cable inserted, providing subtle harmonic distortion. 5V input gives unity gain.979 |
| GAIN CV (touch) | cv | — | Touch point connected to the VCA gain CV input; audio signals here create distortion and AM effects audible at both OUT and DIST outputs.979 |
| IN1 | audio | -12V to 12V | Primary audio input to the transistor ladder low-pass filter; normalled to DIST2 (comparator of DIST1 and OUT) when no cable is inserted.979 |
| IN2 | audio | -12V to 12V | Second audio input to the filter; normalled to DIST when no cable inserted, acting as a distorted resonance path opposing the RES path.979 |
| RES CV | cv | ≥0V | CV input for resonance; normalled to DIST when no cable inserted, applying DIST output as audio-rate resonance modulation — capable of laser sounds and screeches, opposing the IN2 feedback path.979 |
| Outputs (3) | |||
| DIST | audio | ≤12V | Output of the distortion circuit following the VCA; self-limiting, never exceeds approximately 12Vpp.979 |
| DIST OUT (touch) | audio | — | Touch point that mirrors the DIST output signal; can be used to patch or touch the distortion output.979 |
| OUT | audio | ≤22V | VCA output following the filter; switchable to direct filter output via rear header. For a clean 10Vpp input, reaches approximately 10Vpp; can be pushed to rails at approximately 22Vpp.979 |
Parameters 11
| Name | Type | Range | Behavior |
|---|---|---|---|
| FM1 knob | knob | — | Attenuates the FM1 input or its normalled DIST feedback signal applied to the filter frequency modulation path.979 |
| FREQUENCY | knob | — | 979 |
| GAIN | knob | 0% – 100% | 979 |
| GAIN CV knob | knob | — | Attenuates the CV signal applied to the GAIN CV jack; controls how much external CV affects VCA gain.979 |
| IN1 knob | knob | 0% – 100% | Attenuates the IN1 input signal going into the filter; starts to overdrive between 50% and 75% of travel.979 |
| IN2 knob | knob | — | Attenuates the IN2 input signal entering the filter; with no cable inserted, attenuates the normalled DIST feedback signal acting as a distorted resonance path.979 |
| Input to Resonance (J9) | jumper | — | When ON (default), feeds the input signal to the resonance summing point, maintaining bass frequencies and preventing volume loss associated with classic resonance paths. Removing changes resonance character, allowing whistling sounds and self-oscillation to overtake the input.979 |
| Output Source (J10) | jumper | — | Selects the source for the OUT jack: right two pins (default, 'VCA') takes signal from the VCA output; left two pins takes signal from the direct filter output, bypassing the GAIN knob.979 |
| RES | knob | — | Controls resonance of the transistor ladder filter; self-oscillation possible depending on the Resonance Amplitude Trim setting.979 |
| RES CV knob | knob | — | Attenuates the CV signal applied to the RES CV jack; when no cable is inserted, attenuates the normalled DIST feedback for audio-rate resonance modulation.979 |
| x100 SWITCH | switch | 0 – 2 | Three-position switch that multiplies the gain by 100 for extreme distortion: off (no extra gain), latching on (full x100 gain), and momentary on (x100 gain while held).979 |
Firmware history 0 versions
No firmware history recorded.
References 3
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[980]
Schlappi Engineering 100 Grit Quickstart Guidemanual● verified 2026-05-26
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[981]
Schlappi Engineering 100 Grit product pageproduct_page● verified 2026-05-26