the LOUD mouth

Loud hailers are used wherever people need to make themselves heard over a large distance. The design described here is meant for use in cars and thus derives its power from the car battery. This means that the maximum voltage available is only 12 Volts, so some unconventional circuits are required to produce sufficient audio output power. A symmetrical output stage using a transformer is used to feed a 4 ohm loudspeaker, which results in a 16 to 1 power step-up when compared with a conventional push-pul I arrangement. The amplifier operates in class C, which is a bit unusual for audio use. To reduce the effects of (class C) crossover distortion a high frequency bias is superimposed on the input audio signal. The effect of these somewhat unusual features are described in the following paragraphs.