A superglottic and peri-laryngeal apparatus for supraglottic airway device insertion that contemporaneously clears a patient’s upper airway of the tongue and other pharyngeal tissues, and raises the epiglottis without use of the medical practitioner’s fingers in the upper airway. The magnetic-to-acoustic testing device then develops an acoustic output signal representative of the detected magnetic field which may then be used in traditional acoustic monitoring techniques, such as performing a listening check of the magnetic hearing aid system or performing standard ANSI types of measurements, by the audiologist or tester. The cathode assembly has a tungsten cathode with an internal cavity to receive the filament that is secured within a retainer shield made of one of tungsten, molybdenum and graphite by a threaded graphite cylindrical collar.