The diagram shows a tone control with the LM381 IC. The circuit is from a Radio Electronics from February 1990. The power supply is simple.
Found in an English Maplin documentation from 1983, this circuit generates separate frequency...
This circuit uses a piezoelectric transducer to produce sounds like a buzzer. Frequency is...
Guitar preamp (CB22146E) Found in an English publication from 1989, this circuit uses a still...