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 ...

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 ...

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 ...

Having built a number of vacuum tube output transformer-less (OTL) amplifiers in recent years, it seemed as though it might be a good idea to try combining older with newer technology and using both ...

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 ...