The diagram shows a tone control with the LM381 IC. The circuit is from a Radio Electronics from February 1990. The power supply is single.
This circuit can be used to excite push-pull steps of audio amplifiers. From an audio signal at...
This integrator circuit uses the junction FETs which can also be the BF245 or MPF102. The...
This circuit is from a Radio Electronics from September 1969. The integrated circuit used is one...