This circuit is from a 1976 amateur radio manual. The transistor can be the BD136 and the frequency adjustment is done in a potentiometer. The supply can be done with voltages from 6 to 15 V.
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...