Our Purpose
The Tube CAD Journal is an online magazine devoted to tube audio circuit design. We will present some fresh looks at some old tube circuits and some altogether fresh tube circuits as well (yes, new tube circuits are possible). Circuits and more circuits. While we plan on covering complex tube circuits, like phono preamps or power amplifiers, our focus will be primarily on elemental circuits. Elemental circuits are the primary topologies, or part configurations, arrangements that can stand on their own as recognizable functional circuits although they may be part of a larger circuit. A power amplifier circuit, such as the famous Williamson, comprises several sub-circuits: the grounded-cathode amplifier, the split-load phase splitter, the differential amplifier and finally a push-pull output stage. Just as we must understand how a resistor or a capacitor functions in a simple circuit, we must understand the function and logic of these elemental circuits before we can understand more complex compound circuits.

Why a Webzine?
The original intent was to print a conventional magazine. We knew there was a need. A query on our Tube CAD registration cards that a magazine devoted to tube circuit design drew an overwhelmingly loud “YES.” Still, we knew the difficulty and impracticality of starting yet another underground tube audio magazine.

We look forward to your readership, letters, suggestions and contributions.