Crank It Up

I built a small guitar amplifier using the body of an old 1953 Crosley radio, a few simple circuits and a modified hand-cranked flashlight.

The antique radio worked well as an enclosure because it already contained two knobs and a speaker grill. The left knob controls the volume; the right knob controls the gain. The amplifier uses a 386N IC and a handful of other parts readibly available from Radio Shack. The schematics for the circuit can be found in Issue 9 of Make Magazine. Mom, thanks for the subscription!

However, the most interesting piece of the amplifier is the ability to power it using a hand-cranked flashlight. I needed to build a voltage doubler in order for the flashlight to generate enough power to charge the 9 volt battery since the flashlight only outputs about 5 volts. In fact, the amplifier can operate with no battery at all, assuming that you have one of your tone deaf friends on the other end cranking the flashlight.