This tone control was obtained in a Signetics documentation of the 90s. The integrated circuit can be practically any operational amplifier. The power supply is symmetrical.
This 600-ohm output impedance circuit was found in a Radio Electronics from October 1963. The...
Used with infrared remotes at the time, this circuit was found in a 1991 RE Experimenter Handbook....
The circuit presented was obtained in a technical documentation from National Instruments. The...