This chapter lists outs different tools and materials such as monitor amplifier, battery-powered mini-amplifiers, low-power amplifier kit, 25-watt amplifier circuit board, and batteries, and some general supplies to undertake the projects in this book. Whereas “proper” electronic engineering is typically taught with visual reinforcement—staring at an oscilloscope, meters, or a computer screen—we will work by ear, as befits the development of sonic circuitry. A cheap graphic equalizer footpedal, such as sold for guitarists, is an excellent tool for separating the yolks from the whites.