Simulation mode
Measurement, run backwards. Every other view answers “here is a circuit — what is its fingerprint?” Simulation mode answers the inverse: “here is a fingerprint property — what does it sound like, and what do the charts do when I change it?” You get a virtual pedal whose knobs are the fingerprint dimensions, and every chart follows the sliders live.
What it is (and honestly is not)
The virtual pedal is a small software circuit: a filter, a clipper, and a filter, with knobs for the properties the rest of the app measures. The charts you see are not drawn from formulas — PedalScope runs its real measurement pipeline against the software pedal, the same sweeps and two-tone tests it plays through your interface, just with no cables. While you drag a slider the app uses shorter “interactive quality” sweeps (labeled at the top); the Full Quality button re-runs the standard configuration. Nothing here processes your instrument live, and no preset is a model of a product — the “-ish” names are caricatures.
That dogfooding is the point: if simulation’s charts and measurement’s charts ever disagreed, one of them would be lying. Because they share one pipeline, the virtual pedal doubles as a standing test of the whole measurement stack.
The knobs, and the chart each one drives
| Knob | What it is | Watch this chart |
|---|---|---|
| Drive | Pre-gain into the clipper (−20…+40 dB) | Your position on the gain journey |
| Clip threshold | Where the clipper bites, with Si / LED / rails presets | The compression knee location |
| Knee softness | Hard edge ↔ soft knee | Knee abruptness; how fast high harmonics die off in the Harmonics chart |
| Asymmetry | Positive vs. negative thresholds pulled apart | Even-harmonic content — H2 bloom in the Harmonics chart |
| Slew-rate limit | An output-stage speed limit (the one memoryful element) | Distortion rising toward treble in the gain journey |
| Pre-filter (HPF + tilt) | What reaches the clipper | Low-end chord roughness; voicing into the clipper |
| Post-filter (LP + tilt) | The tone control after clipping | H₁ shaping across the Harmonics chart |
The flagship experiment: set asymmetry to zero and look at the Harmonics chart — the even-order stems sit at the floor, because a perfectly symmetric clipper cannot create them. Now drag the slider and watch H2 rise out of the noise, then press play on the Symmetry morph panel below the transfer curve and hear what you just measured.
▶ Open the asymmetric Fuzz-ish preset
Presets
Four starting points, named for the flavor they chase, not the circuits they’d need to be: Rat-ish (Si) and Rat-ish (LED) differ only in clip threshold — measure both compressions and the knee moves by the diode ratio, about 9 dB. TS-ish is a soft knee behind a bass-cutting pre-filter. Fuzz-ish is asymmetric with almost no headroom.
▶ Try Rat-ish (LED) — then compare the knees
Matching a real pedal
The Compare to Library section overlays a hardware Harmonics measurement from your library on the virtual pedal’s, with the same distance number the Compare view uses. Dialing the virtual pedal until the distance shrinks is the best exercise in the app: every move that helps teaches you which knob owns which part of the chart. Check the drive chips first — if the sweep levels differ, part of the gap is drive, not circuit character.
A snapshot of the virtual pedal can be saved to the library. It arrives marked simulated, with the full parameter recipe stored on the record — a measurement of software is still a measurement, but it never masquerades as hardware.
Common misreadings
“The charts look coarser while I drag.” Interactive quality trades sweep length for responsiveness and says so in the header chip. Numbers you plan to quote deserve a Full Quality pass.
The slew knob is not a tone control. A low-pass filter removes treble from the output; the slew limit distorts fast signals — quiet, slow playing stays clean while high notes and hard attacks grow extra harmonics. That frequency tilt in THD is its signature.
Matching a fingerprint is not cloning a pedal. The virtual pedal has no supply sag, no temperature drift, no interaction with your guitar’s pickups. A close overlay means the static recipe matches at that drive — feel is a bigger word than that.
Try it now: open Simulation mode.