We found this circuit in an old documentation, but the components used offer no difficulty in obtaining it. The CMOS integrated circuits are powered by a 6V supply.
This circuit includes the amplifier for the signals, being fully transistorized and using varicap...
This bass booster preamp is from an English publication (1966). We can mount it with more modern...
The operational amplifier is old. The circuit is from an 80's documentation but can be designed...