This balance control for the channels of a stereo system was found in a 1969 Mullard documentation. The transistors may be the modern BC548 equivalents.
Any general purpose PNP transistor such as the BC558 can be used on this circuit from an old...
This circuit is from a 1965 General Electric hobby manual. The circuit can be assembled with...
This circuit was found in a Maxim documentation from the 90s. It is valid for the lower income types...