This circuit was found in a Japanese publication in 1975. It provides 30 W per channel using the SI-1030G modules. The module must be mounted on an excellent heat sink.
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....