We found this circuit in a 1977 factory documentation. The operational amplifiers can be 741 and the symmetrical power supply. Capacitors can be changed for operation at other frequencies.
This treble and bass control drains some milliamperes from a 12 V supply and can be used with any...
This circuit was obtained from Dutch documentation from 1967. It uses transistors of the time...
This circuit was found in a 1980s documentation for amateur radio. The circuit is for 9 MHz...