The 6AU6A differs from the 6AU6 sharp cut-off pentode in that the heater is controlled such that, when used with other similar valves, heater voltage surges are minimised and the warm-up time is defined.
The valve has etched identification and the green overprint.
The GE logo.
Looking through the holes in the ends of the anode reveals the three wire grids. The suppressor grid notched rod can be seen and further in are the two inner grids.
The thin glass tube envelope is 18 mm in diameter and excluding the B7G base pins the valve is 47 mm tall.
Reference: Data-sheet. Type 6AU6A was first introduced in 1958. See also1958 adverts.
