The body of a piezoelectrically operable ink jet printhead (12) is mounted in an upper side surface groove (48) formed in a mounting plate member (14). A rear bottom section (26) of the printhead body has an exposed top side surface portion (30) which is flush with the top side (44) of the mounting plate member and terminates forwardly of its rear end (42). A high density parallel array of mutually spaced linear conductive traces (52) is formed on this exposed top side surface portion, the traces being used to transmit electrical operating signals from a separate electronic driver to piezoelectrically drivable channel sidewall sections (36) within the interior of the printhead body. A multitiered printed circuit board (16) secured to the top side of the mounting plate member is used to connect the printhead to the electronic driver. The circuit board has a series of linear traces (52a) formed on its bottom side which register with and are soldered to the closely spaced printhead body traces (52), a spaced series of lower density spacing contact pads (54a) formed on its top side and releasably engageable with correspondingly spaced contact pads on the electronic driver, and internal crossover circuitry (62) that operatively connects the high density underside linear traces of the circuit board to its lower density top side contact pads.