The young man shown here earned his girl’s admiring gaze by putting together two companion projects shown in the April 1948 issue of Popular Mechanics. The first was a relatively modest crystal set featuring a tapped coil, capable of pulling in the local stations with suitable antenna and ground connections.

But what really impressed her was the loudspeaker volume achieved with the audio amplifier using a 1H5GT and 1Q5GT tube to drive the  3″ speaker handsomely mounted on the front panel. The crystal set, of course, needed no power source. The amplifier ran from a 1-1/2 volt dry cell and two 45 volt batteries in series.

In addition to working well with the crystal set, the amplifier could be used with a crystal phono pickup or other electronic projects.