Abstract: A bridge audio amplifier is disclosed which includes an input stage for receiving an audio input signal and having a bias amplifier and a signal amplifier which provide a combined output current containing a substantially constant dc component and an ac component which is dependent on the input signal and the relative transconductance of the bias and signal amplifiers. The transconductance of the bias and signal amplifiers is reciprocably varied by a dc control voltage to vary the ac component of the current. The output current is converted to a voltage signal and applied to an output stage for driving a speaker. Two such audio amplifiers driving front and rear speakers may be employed to achieve a low level fade function.