The CV2747 (commercially the 6U5G) is an American design of Magic Eye tuning indicator. The electrode assembly is mounted centrally in the envelope with the amplifier triode feeding the display. The display is viewed through the dome.
The KB/FB identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the FB identifies the maker as STC, Footscray.
The amplifier triode anode connects directly to the display bowl.
A closer view.
Here the triode control grid winding is easier to see.
The display bowl. The winding around the cathode was found to increase the service life.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 86 mm tall.
References: Data-sheet, 1043 & 1040. Type CV2747 was first introduced in 1952. See also1952 adverts.
