Abstract: A class AB amplifier output circuit having two output devices is implemented using single polarity GaAs devices. The exemplified circuit comprises a bias control loop that includes the gate-to-source voltage of one of the output devices, the gate-to-source voltage of a device that the replicates the gate-to-source voltage of the other output device, and a pair of diodes. The configuration of the control loop is such that the bias current in the two output devices is controlled and set to approximately one quarter of I.sub.DSS. The output circuit has a differential input that may be coupled to the output of a preamplifier circuit in a conventional manner.