Indicated for automotive use, this circuit was found in a Popular Electronics from the 90s. The circuit uses a power transistor that must be equipped with a heatsink.
In the figure we have the typical circuit of a Baxandall tone control applied to an operational...
This circuit makes use of older operational amplifiers, but can be designed on the basis of modern...
This circuit that can be assembled in an “aspirin box” was found in the Radio Electronics magazine of...