Guitar Amplifier Electronics: Basic Theory book

Basic Theory - using 21st-Century technology to design vacuum tube preamps, power amps, and power supplies

Fundamentals of Guitar Amplifier System Design book

System Design - a professional methodology for crafting a complete guitar amplifier

Guitar Amplifier Electronics: Circuit Simulation book

Circuit Simulation - modeling vacuum tube guitar amplifiers using SPICE

calculatorLaunch me!

What does this calculator do?

This calculator was created to accompany our new book on SPICE simulation of guitar amplifier circuits.1 At one point in writing a large-signal triode model, a curve fit is required using quadratic regression. As a convenience for readers of the book, this calculator performs these calculations automatically. Specifically, the calculator computes optimal values of K1, K2, and K3 for the formula

A = K1(VG)2 + K2(VG) + K3

The algorithm requires at least 3 data points and handles up to 9 data points. Leave unused inputs equal to "0".


1Richard Kuehnel, Guitar Amplifier Electronics: Circuit Simulation, (Seattle: Amp Books, 2019).