The CV511 makes no secret of the fact that it is the equivalent of the commercial 6V6GT. The 6V6 family of beam tetrodes came in many constructions and were very popular as the final audio stage of broadcast receivers. The original 6V6 was an American metal can valve from the mid 1930s.
The valves were capable of push pull use but the normal environment was as a single end output stage. In the 21st century the 6V6 design is still a popular valve for audio designs.
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 UK Government up arrow and the letters NA.
The commercial Type 6V6GTY - Glass tubular on a wood-loaded phenolic base cap.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 71 mm tall.
References: Data-sheet, 1040 & 1043. Type CV511 was first introduced in 1937. See also1937 adverts.
