Online Articles on Guitar Amp Design

Tube Amp Algebra is a tutorial on the mathematics of tube amp design. It begins with simple concepts like electric charge and current, and then steadily progresses to more difficult subjects like complex impedance and Laplace transforms. All of the examples focus on guitar amplifier circuits.

The Fender Bassman 5F6-A presents an overview of the legendary 5F6-A circuit. Included is a fascinating study of the tonal effects of AC Power Supply Ripple.

Fender Bassman Tonestack provides in-depth analysis of the 5F6-A tone controls. This article is not for the mathematically faint of heart, but there's a big payoff: Bode's methods reveal Jim Marshall's intent when he modified the Bassman's tone stack. Moreover, Bode allows us to create a step-by-step methodology for customizing this key circuit to meet our specific performance objectives.

Vacuum Tube Technology includes a collection of articles on historical events surrounding vacuum tube amplifiers. There is an article on Alan Blumlein's invention of the "ultralinear" amplifier, including the original patent document. Then there is a tutorial on how Leo Fender and Jim Marshall were able to design amplifiers without using electronic calculators. We also reproduce an extensive dictionary of vacuum tube terminology, circa 1950.