@Muse - This circuit implements a classic **hard-clipping distortion pedal** (found in pedals such as the MXR Distortion+ and ProCo RAT), which turns a clean guitar signal into a saturated, harmonic-rich overdrive.
### How It Works
1. **Input Stage:** #Vin simulates a guitar pickup generating a $200\text{ mV}$ peak, $440\text{ Hz}$ audio signal at node #in.
2. **High-Gain Non-Inverting Amplifier:** Operational amplifier #U1 amplifies the signal with a gain set by feedback resistor #Rf and resistor #R1:
$$A_v \approx 1 + \frac{R_f}{R_1} = 1 + \frac{50\text{ k}\Omega}{1\text{ k}\Omega} = 51$$
Capacitor #C1 forms a high-pass filter with #R1 ($f_c = \frac{1}{2\pi R_1 C_1} \approx 159\text{ Hz}$) that rolls off sub-bass rumble to keep the distortion tight and clear.
3. **Hard-Clipping Diodes:** The amplified signal passes through current-limiting resistor #R2 to an antiparallel pair of silicon diodes, #D1 and #D2.
- When the voltage exceeds $+V_F \approx +0.7\text{ V}$, #D1 conducts and clamps the positive peak.
- When the voltage drops below $-V_F \approx -0.7\text{ V}$, #D2 conducts and clamps the negative peak.
4. **Output Waveform:** The oscilloscope compares the smooth clean input #in (blue trace) with the squared-off, saturated output #out (green trace), producing the classic aggressive guitar distortion sound.
