This wired control circuit serves both volume and balance between channels. We found it in Radio Electronics magazine from August 1968. Transistors are common general-purpose types
This filter, from an audio publication from 1977, passes the frequency range corresponding to the...
In the figure we have three voltage doubler configurations that can be used in high and low...
This circuit was found in Motorola documentation from 1966. The lamps are according to power and...