We found this circuit in a 1977 factory documentation. The operational amplifiers can be 741 and the symmetrical power supply. Capacitors can be changed for operation at other frequencies.
The integrated circuit used in this stereo preamp is uncommon today, but the circuit can be...
This circuit was found in a 1967 General Electric manual. It is intended for the control of high...
Carbon microphones are no longer used in most projects. However, finding one in the scrap metal, it...