This circuit is from a 1980s Motorola documentation. The circuit can be made with modern equivalent components. The original circuit is for the 115 Vac (110 V) grid and has two settings.
Using an operational amplifier, the figure shows how to convert the waveform to low frequency...
This is the power step of the previous circuit. Output transistors must be mounted on good heat...
The UM3562 integrated circuit (not very easy to find) synthesizes three types of sound that...