This circuit was found in the 1990 Motorola Dataar Linear. We can mount it with more modern equivalent transistors. Output transistors shall be provided with heat radiators.
The transistors are 2N918, 2N3464 and other RF equivalents of the time for Q1. For Q2, 2N3399, 2N2894...
This circuit, which can be used as a shield, was found in a 90s Electronic Design. The circuit...
This interesting intercom circuit was obtained from an Argentine publication from the 1970s....