Method

A Bonzai plugin is not a set of filters tuned to sound like an instrument. It is the instrument's circuit.

From the schematic

We start from the service documentation: the factory's own drawings and parts lists. Every resistor, capacitor, transistor, diode and op-amp is entered as it is drawn, with its value and its part type.

Solved together

The whole circuit is then solved numerically at audio rate, all parts at once. Stages load each other as they do on the board, so driving one harder changes what the next one does.

Checked

Each model is compared with a circuit simulator running the same circuit with full device models. Where the original's maker published adjustment procedures, we run them on the model in place of tuning by ear.

Where the drawing ends

Some parts were never documented: a sealed gain cell, a custom chip. Where we had to reconstruct one from its published behaviour, the instrument's page says so.

Light enough to use

An instrument is not finished until it runs under a tenth of one processor core with every voice sounding.