This circuit was found in a 1969 Mullard documentation. Used transistors can be replaced with modern equivalents. Output transistors may be BD135 and 136 with heatsinks.
The diagram shows a tone control with the LM381 IC. The circuit is from a Radio Electronics from...
Very simple, this radio control circuit for short distances was found in an Electronic Design from...
From an article in Radio Electronics magazine, May 1989, this circuit requires a dual power...