The 75 is a double diode triode for superhet AM detection, AGC detection and first audio voltage amplifier.The 75 has a 6.3 Volt heater and a UX6 base. The 2A6 has the same rating and base but a 2.5 Volt heater. The 6B6G is also the same basic valve but has an IO base.Thanks to Bob Hopkins for sending the image.The classic envelope is 36 mm in diameter, and excluding the UX6 base pins is 125 mm tall.Reference: Data-sheet. Type 75 was first introduced in 1937. See also 1937 adverts. |