The 6AU6 is an American design, the European Type designation is EF94. The 6AU6 has controlled warm-up times and is a sharp cut-off type, that is not AGC controlled. Usage is RF or AF amplification.
The Made in USa and within the outer screen is the anode and three wire grids.
The RCA logo. The heater is coiled.
The thin glass tube envelope is 18 mm in diameter and excluding the B7G base pins, is 47 mm tall.
References: Data-sheet & 1040. Type 6AU6 was first introduced in 1946. See also1946 adverts.
