This circuit is from a manual from the 80's and the operational one used, uncommon nowadays, can be replaced by a modern equivalent. The power supply must be symmetrical.
Found in an English documentation, this circuit provides a 50 Hz signal according to the local...
This circuit provides 15W per channel and can operate with a single power supply. The circuit is...
This preamplifier for the 6 or 2-meter range was obtained from an American documentation from the...