The power supply for this 1972 circuit must be symmetrical and the BC549 transistors. Care with the layout is important to avoid capturing tinnitus.
This configuration was found in a 1990s documentation. Modern operational amplifiers can be used...
Found in a 1960 Gernsback documentation, this circuit triggers an electromechanical counter of the...
This powerful amplifier was part of commercial sound circuits from the 90s. The integrated circuit...