Western Electric Model 38A (Audiphone) Carbon Hearing Aid The Western Electric Model 38A carbon hearing aid was manufactured by the Western Electric Company in 1932. The unit weighed 11 oz. without batteries and measured 5¾” by 3” by ¾”. There was a metal clip on the rear of the microphone/amplifier unit to attach it to the clothing. Batteries were contained in a separate battery case (not shown). Operating voltage was typically 4½ volts. |