[R-390] CV133 vs 6C4

[Andy Jackson G8JAC]

|> I wonder whether they made identical tubes but labeled with whatever
|>the CV equivalent is for a 5814A etc.

5814A = 12AU7 = ECC82 = CV491
5814WA = M8136 = CV4003 = 6189


|>Someone once tried to convince me that the euro EC-tube number system
|>(e.g. ECC82) made a lot more sense than our system (filmanet voltage +
|>letter(s) + number of terminals) but they didn't convince me. Maybe
|>there is a rhyme and reason to the CV numbers but I don't see it.

E = 6.3v heater
C = Triode
C = second triode
82 Base type (B9A)

There is no logic to CV numbers, and many exceptions to any percieved
"rules", but the CV sequence started during WW2 to try and produce a common
numbering system for  devices used by the navy, army, and the RAF, plus
other government agencies such as the General Post Office (GPO), all of
which used their own numbering systems in addition to those used by US and
european manufacturers.  CV numbers were also allotted to devices with
tighter specifications that normal, ruggedised versions and variations for
special purposes.  Later, the system expanded to include semiconductors.

http://www.tubecollector.org/ will tell you everything you need to know
about the CV numbering system and a whole lot more.

Andy G8JAC