Here’s a way of transmitting audio that makes it virtually impossible for someone else to listen in. Instead of sending radio waves bouncing all over creation, this uses the focused light of a laser ...

The intercom circuit described here uses two transistors, an audio transformer, and a few passive components in addition to condenser microphone and low-wattage speaker (refer Fig. 1). The complete ...

It was a cold January Saturday night in Chicago and we had big plans. Buddy Guy’s Legends bar was packed. We setup directly under one of the PA speakers less than 15′ from the stage. Time to celebrate ...

Remember Kenneth Lundgren’s unidentified audio transformer, discussed earlier and pictured here? There was no identification marking, so Kenneth invited thoughts from our readers about the type of ...

In professional audio, analog interconnections between devices typically use “balanced” interfaces. At the source, a balanced output stage differentially drives two signal wires (theoretically with ...

Pilot model 302 audio transformer. Marked: "Pilot No. 302 / Audio Freq. Transformer / Redi-Blox / Manufactured by / Pilot Electric Mfg. Co., Inc. / Brooklyn, New York, U.S.A." An audio output ...