This high input impedance tone control circuit was found in American documentation from the 1980s. Equivalent operational amplifiers and FTEs can be used.
Found in an EDN from the 80's, this circuit makes use of an operational one of the time. The...
This circuit is from the 80's, using an integrated of the time. The circuit serves as a reference,...
The circuit presented is from the Linear Applications Handbook of the National Semiconductor of...