What is a SPICE Netlist?
What a SPICE netlist actually is, how to read a line like 'R1 IN VREF 10k', and why exporting your guitar pedal schematic to SPICE lets you simulate before you solder.
A circuit, but in plain text
A SPICE netlist is your schematic written as a text file. Every component is one line. Every line says: 'this is what kind of part I am, these are the two (or three) nodes I connect to, and this is my value.' A simulator reads that file, builds a giant system of equations from Kirchhoff's laws, and solves them.
That's it. There's no magic. The format has been around since the early 1970s and basically every circuit simulator on Earth — LTspice, ngspice, PSpice, the simulator inside Pedal Bench — speaks some dialect of it.
Reading a single line
The format is: `<name> <node+> <node−> <value>`. So:
- `R1 IN VREF 10k` means a 10 kΩ resistor named R1 between the nodes called IN and VREF.
- `C2 OUT 0 100n` means a 100 nF capacitor between node OUT and ground (node 0 is always ground in SPICE).
- `D1 OUT VREF 1N4148` means a 1N4148 diode from OUT to VREF.
- `Q1 COL BASE EMIT 2N3904` means a 2N3904 transistor — collector, base, emitter.
First letter tells you the part class: R for resistor, C for cap, L for inductor, D for diode, Q for BJT transistor, M for MOSFET, V for voltage source, X for a subcircuit (most op-amps).
Why it matters when you're building pedals
The moment your schematic is a netlist, you can do things you can't do with a soldering iron:
- Sweep one resistor from 1 k to 100 k and plot the result in seconds.
- Plot a frequency response of your tone stack across 20 Hz–20 kHz.
- See the exact waveform at any node, before any electrons ever touch a real diode.
- Share the design — every pedal builder on the planet can open your .cir file in their own simulator.
The netlist is the lingua franca. Learn to read it and you can read anyone's schematic, including the cryptic ones on diystompboxes.com from 2003.
Getting yours out of Pedal Bench
Open any project, click the Netlist view, and the schematic appears as text you can copy, save, or paste straight into LTspice. There's also a one-click Export → LTspice (.cir) if you want a file. The Simulate tab uses the same netlist under the hood — so what you see in the netlist view is exactly what the simulator is solving.