Abstract: A variable displacement pump control assembly as for an axial piston pump having a swash plate actuating piston characterized in that the control assembly is embodied in the pump housing to provide a pressure compensated pump, or to provide a pressure compensated pump having an auxiliary modulator to control the pressure applied to the swash plate actuating piston to maintain a predetermined pressure drop across a variable area metering orifice embodied as in a directional control valve for a fluid motor, or to provide a pressure compensated pump having a horsepower modulator with or without the auxiliary modulator, said horsepower modulator providing desired control of horsepower in relation to pump delivery pressure and displacement.