This circuit, obtained from a 1965 magazine, can still be assembled using some modern equivalent components. The transistors may be BC558 and the transformer is obtained from a disused transistor radio.
We found this circuit in a 1995 documentation. It is a two-channel preamplifier for supplying a...
The presented circuit was found in the National Semiconductor's Linear Applications Handbook from...
This circuit is from a Popular Electronics from the 90's. The audio amplifier admits equivalent. The...