We found this amplifier in a 1990 documentation. The transistors are common, having been made their update because the original were no common today. The source should be at least 1 A and the output transistors be mounted in good heat radiators. For a stereo version of the source must be at least 2 A and two circuit as indicated must be mounted, one for each channel. The source must have good filtering and signal input cables must be shielded. The circuit needs a few hundred millivolts to be excited to full power.
