Well, Mazda were another manufacturer who wanted to stand out and indeed made their own version of the Octal base with a fatter spigot known as the Mazda Octal or MO base. Their valve numbering system was a bit kooky too and needs some explanation.
The typical Mazda valve type number was an alphanumeric affair comprising of; a numerical prefix followed by a letter which in turn was followed by a mumerical suffix.
The numerical prefix always indicated the heater voltage EXCEPT where 10, 20 & 30 were used which indicated the heater current draw in 0.1A. A further exception was for rectifier valves whose designation started only with a letter - eg U31, UU5 etc.
The letter indicated the valve type with letters allocated as per the following table.
|D||Signal diode or diode(s)|
|FD||Signal tetrode/pentode plus diode(s)|
|FL||Signal tetrode/pentode plus triode|
|L||Signal triode or triode(s)|
|LD||Signal triode plus diode(s)|
|PL||Output tetrode/pentode plus triode|
The numerical suffix was a sequentially assigned development number.
Here are a couple of examples: -
UU5 - the 5th full-wave rectifier developed by Mazda.
20P1 - the 1st 200mA heater output pentode developed by Mazda.