We found this circuit in the July 1988 Radio Electronics magazine. The frequencies are given by capacitor C1 and the voltage input is made at pin 1.
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....