We found this circuit in a 90s Popular Electronics. The circuit uses a pickup coil that consists of 100 to 200 turns of wire 28 around the cable to be monitored.
This circuit came out in an American magazine that no longer exists. It's the Electronic...
This circuit originally came out in a Budget Electronics from 1981. The American magazine no...
This is the traditional audio preamp configuration with the National Semiconductor LM382. The...