This audio circuit was published in a Rado Electronics issue from October 1963. The transistors are from the time and the output is low impedance. Power is supplied with a voltage of 12 V.
This circuit was found in the July 1969 issue of Radio Electronics magazine. It also appeared in...
We found this circuit in the August 1994 Electronics Now magazine. The circuit is based on the...
This 4.5 MHz oscillator, or according to the crystal, was found in American documentation from the...