A mud pulse telemetry valve assembly and method including a mud valve sub and a mud pulse telemetry valve. The mud pulse telemetry valve having a flow tube positioned within the mud valve sub in a way that at least a portion of an outer surface of the flow tube is spaced a distance from at least a portion of an inner surface of the mud valve sub to form a hydraulic passageway having an upstream end and a downstream end. The mud pulse telemetry valve further having a control valve assembly and a pilot valve assembly.