A high power audio frequency push-pull transistor amplifier to drive an electro-magnetic vibrator

A 1 kVA electro-magnetic vibrator, having a nominal impedance of 10 ohms and requiring a 150 V peak excitation source, is taken as a model for studying the problems involved in driving large vibrators. The output transformer, usually associated with audio power amplifiers, determines the amplifier low frequency response. A design for a high power transformerless transistor push-pull amplifier is considered, with emphasis in particular on the problems associated with transistor series/parallel arrangements, and the power handling requirements of an amplifier driving a load of low power factor.