A 2D ultrasound imaging system has a number of different probes for different clinical applications. Each 2D imaging probe has a one dimensional array transducer and one or more microbeamformers coupled to the individual elements of the array. Preferably the microbeamformers are the same, and serve as a standard component of the system. The microbeamformers combine signals from the elements of their transducers and every probe has from four to sixteen outputs of partially beamformed signals. The mainframe system has a beamformer with four to sixteen channels, which completes the beamformation process for each probe.