p↗pedalbench.
CIRCUIT LAB / v1.4
YOUR WORKBENCH

Diode overdrive

Select a component to edit its parameters
100%
1 selected
SCHEMATIC7 components · 8 connections
R rotate ⌫ delete Esc cancel

Signal analyzer

Ready to simulate
Input Output1 kHz sine · 4 cycles
Run the circuit to inspect the signal.
OUTPUT / PEAK— V
GAIN / FUNDAMENTAL— dB
THD / H2–H10— %
Ground-referenced voltages · simplified component models
START WITH A CIRCUIT

Explore circuits by source.

Choose a source to browse its circuits. Every component and connection is yours to change.

These are educational circuit stages, not exact models of commercial pedals. Loading an example can be undone.
THE WORKBENCH GUIDE

From schematic to signal.

01

Build your circuit

Drag components from the library or click to place them. Click a terminal, then another terminal to connect them. Wire crossings do not create junctions; connect to the same terminal to join a net.

Shift-click components or use Box select (B) to select a group. Copy with Ctrl/⌘C, open another circuit, then paste with Ctrl/⌘V. The toolbar offers the same actions. Internal connections are preserved; reconnect any external terminals. Paste is one Undo step.

02

Dial in the values

Select a component to edit it. Values accept engineering notation: 10k, 4.7n, 100u. Use R to rotate, Delete to remove, and arrow keys to move. All ground symbols share 0 V.

03

Inspect the signal

Run a 1 kHz sine wave and compare input with output over four cycles. Change the frequency or amplitude to explore filtering and clipping. Results are marked stale after edits.

Know the model

Pedalbench solves DC bias first, then uses modified nodal analysis, backward-Euler capacitors, and Newton iteration for the sine response. Triode sections use published Koren 12AX7/12AU7 fits. EF86 pentodes use a Pedalbench calibration to Philips data, including screen current. Each tube uses its compatible heater load. Add tube stage inserts powered input, output or both stages into the current circuit. The tube and power guide describes the models and sources. Diodes use a simplified Shockley equation at 25.85 mV thermal voltage. The op-amp requires negative feedback and has finite gain and bounded output; its ± supply limits are implicit.

NPN/PNP transistors can use an explicit generic silicon Ebers–Moll model with editable gains and transport saturation current. Imported transistor markers stay unmodeled until you select a model. Transistor capacitance, Early effect, breakdown, temperature drift and germanium leakage are omitted. This version does not model inductors, component tolerances, diode capacitance, noise or higher-order op-amp behavior. Named op-amp variants include a single-pole bandwidth and slew limit; the generic static op-amp remains available. Photoresistors use manually set illumination, without optical coupling or response-time modeling. Named diodes and LEDs use editable forward-curve approximations. Parts & variants links each preset to its documentation. Delay, OTA, timer, logic, charge-pump and power-amplifier ICs are numbered pinout references without simulation. The listening panel plays captured sine harmonics or processes a complete local guitar recording in real time, with looping and parameter changes. Playback removes DC; monitoring is separate from circuit volume. The transient run is finite, so very slow networks may not settle. THD covers harmonics 2–10. AC trace removes the output mean for display; DC bias remains visible separately. HV converters and heater regulators are averaged models; switching noise and hardware protection are not simulated. Use a full SPICE tool for hardware validation.

Transistor model ↗Nodal analysis ↗Transient models ↗Op-amp model ↗