An apparatus or system comprising, or a method utilizing, a pressure-tight head assembly coupling a multi-conductor wireline cable operable for downhole operations within a borehole extending into a subterranean formation. The head assembly comprises: an upper head attachment; a lower head attachment; an upper compression seal assembly; a gripper cone; and a rope socket. The upper compression seal assembly is threaded into and/or otherwise coupled to the upper head attachment in a manner causing the gripper cone to tighten onto the cable jacket.