This common circuit using operational amplifiers was found in the 1993 issue of Radio Electronics Special Projects. The circuit is sandwiched between the pickup and the amplifier input.
This circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit is based...
This circuit was found in Electronics Today International of the 80's. The circuit uses still...
This circuit is from the National Semiconductor FET Databook. The coil data is provided with the...