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 a Radio Electronics Constructor, English magazine from April 1976; The...
This circuit was found in General Electric documentation from 1966. The circuit is suitable for any...
This 48 V circuit with a capacity of up to 105 V was found in a 2005 Linear Technology manual. The...