This 1967 General Electric circuit makes use of an array of 3 (integrated) transistors for an amplifier stage. The circuit has a 500 mV output.
This good power amplifier, a few tens of watts, is part of an article in the December 1972 Radio...
The circuit presented in a 2009 documentation is simple based on the NE558 and NE555 ICs with...
I got this circuit from an English magazine from 1977. It can still be easily assembled, as the...