This 50 kHz to 250 W circuit was found in an old RCA documentation. The transformer is a commercial type of the time and the output voltage is 80 to 90 V.
Using the LM3909 this circuit was found in the January 1992 issue of Radio Electronics magazine....
) This two-transistor circuit features excellent gain operating with low impedance microphones. The...
This circuit was found in an English publication in 1986, but it can still be implemented by...