[ARC5] A Tube Puzzle

[Kenneth G. Gordon]

On 30 Apr 2012 at 14:02, J. Forster wrote:

> Hi,
> 
> My understanding was that standard tube conventions had the leading
> digit(s) as the filament voltage:
> 
> 1B3   = 1 V
> 2X2   = 2 V
> 5Y3   = 5 V
> 6X5   = 6 V
> 12AX7 = 12 V
> 35W4  = 35 V
> 50C5  = 50 V
> 117L7 = 117 V
> 
> etc.
> 
> How does a 2C51W dual triode fit in? It has a 6 V filament?

How about the loctals, all of which start with either 7 or 14, and yet have 6.3 
v and 12.6 volt filaments?

Ken W7EKB