Circuit Validation

Circuit-level work needs validation before it is treated as a trustworthy model. Public references are useful, but measured hardware, SPICE, and deterministic Rust fixtures are what make a model auditable.

Minimum Evidence

• Component values have a source and confidence level.
• Stateful capacitors map to explicit model state.
• External connections expose voltage and impedance.
• Controls have measured, documented, or deliberately assumed taper behavior.
• No stage relies on unexplained magic gain constants.

Hardware Measurements

When safe and available, capture:

• supply voltage and current draw,
• input impedance across frequency,
• output impedance across control positions,
• key internal node waveforms,
• bypass behavior,
• potentiometer resistance and taper.

SPICE References

For each reusable circuit cell:

• verify DC operating point,
• run AC sweeps,
• run transient tests at realistic amplitudes,
• export reference curves for Rust comparison.

Rust tests should compare operating points, RMS levels, harmonic magnitudes, and fixed-frequency tone-stack response.

Audio Regression

For full models, keep rendered WAV fixtures and monitor logs around representative settings. Automated checks should prefer direct target/release/greybound-cli --input-wav ... --output-wav ... --render-seconds ... commands because they exit by themselves.