The simplicity of this circuit is fascinating ... is not much more complicated than that. It includes an audio output transformer which boosts the resistance of the audio signal.

The tube is an EF86 pentode, and the audio output is transformer-balanced. To start, I had to etch three small circuit boards; one for the power supply, one for the mic circuit and one for the tube ...

The field of wave digital modeling has emerged as a robust framework for simulating nonlinear audio circuits with high ... such as transistors and transformers—is essential to achieving ...