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.
The Pinnacle name and pennant
The triode is at the top and below the middle mica is the screen covering the two diode anodes.
The face view of both sections.
A closer view of the diode screen.
Here are the two rod diode anodes.
The classic envelope is 38 mm in diameter, and excluding the UX6 base pins is 98 mm tall.
Reference: Data-sheet. Type 75 was first introduced in 1937. See also1937 adverts.
