This circuit was found in the September 1989 issue of Radio Electronics magazine. The circuit uses components that support modern equivalents such as the operational amplifier.
This 1975 documentation circuit must use a 6 to 9 V symmetrical source and the signal cables must...
With the circuit shown in the figure it is possible to digitally control the gain of an...
The audio amplifier integrated circuit used in this 1990 project is not very common today....