Portable electronic instruments. These photos show knobs, nuts, knurled, and know-how (Pete’s). These are working photos of our differential amplifier project. They show how we can get the electrical boards to line up with the mechanical connectors, and controls. And how an extra layer of plexi can be used to add a nice finish, and provide a solution to the incompatible height of the controls (note the nut is recessed by the plexi).