This circuit allows you to adjust the balance between channels of a stereo amplifier. The circuit makes use of an analog indicator with zero in the center of the scale.
The operational amplifier taken as an example is uncommon today, but the configuration can be made...
The integrated circuit used in this regulator is not easy to obtain, since the publication is from...
This configuration was obtained in a 1977 FET Databook. The circuit can be practically any JFET...