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 ...

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 ...

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 ...

You probably have needed to match impedances and levels from time to time. Perhaps you want to connect a consumer computer’s sound card to your console; or you need to lower a balanced output level to ...

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 ...