Found in an 1868 Mullard documentation this circuit has a dynamic range of 10 Hz to 25,000 Hz. Modern equivalent transistors can be used.
This circuit is from a 1991 publication, but it can be assembled with more modern components. We...
This circuit provides a current given by the components calculated according to the formula next...
Published in Radio Electronics in October 1963, this circuit increases the audio output of a small...