This is the traditional audio preamp configuration with the National Semiconductor LM382. The circuit has good gain and can be used with magnetic pickups or from signals from an auxiliary input.
This well-designed sinusoidal oscillator by Wien bridge was found in ancient European...
This is a circuit for testing small lamps and LEDs. The lamps that can be tested are the ones...
Found in a Popular Electronics from the 90's, this circuit can be implemented with almost any...