The CV729 is a pre-war design of full wave rectifier. The maximum rectified output is 175 mA. The minimum series resistance to prevent excessive current peaks is 100 Ω.
The commercial equivalent is the 5V4G.
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 octagonal lozenge is typically found on RCA products.
The twin rectifier sections seen side on. Each central rod connects to the top of an anodes.
The anodes seen face on.
The classic envelope is 44 mm in diameter and, excluding the IO base pins, is 100 mm tall.
