This circuit was found in ancient American documentation. Equivalent operational amplifiers can be used. The power supply must be symmetrical. The circuit provides an average output.
Circuits like this one, using the LM386 audio amplifier, are available from other sources in this...
This bass and treble control only attenuates the corresponding signals, requiring further...
Using a large inductance, this circuit was found in a Popular Electronics from the 90s. The...