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Ralph Mowery

In article ,
says...

On Tuesday, February 28, 2017 at 2:50:33 PM UTC-5, micky wrote:
In sci.electronics.repair, on Mon, 27 Feb 2017 15:36:52 -0800, Jeff
Liebermann wrote:

On Mon, 27 Feb 2017 16:38:10 -0600, wrote:

I have yet to find a decent chart which explains the reason for the
numbers/letters used on tubes. (For USA tubes).

.

would seem that the semiconductor people had not learned the lessons
of tube numbering, and repeated the basic mistakes.

As to 813 etc. I haven't found any all numerica names but I wouldn't
have thought the 8 referred to voltage. That I would have taken as some
subset of sequential numeric naming.

I suspect the very early tubes were simply numbered in order of development. My old Radiola uses an 80, a 171 and a bunch of 27s. The 27s are 2.5v filaments and the 171 and 80 are 5v.

As with all things they start off with a sysem and as new items are
developed that system falls apart. I think tubes were numbered in order
to start with. Then they were listed as the first number being the
filiment voltage, letters to indicate what type and the last number the
number of elements.

Some power tubes started with a number a dash and another several
numbers such as a 3-500. That was the number of elements and the plate
dissaplation. A 4x150 started the same way. Later it was a 4cx150 that
indicated a ceramic seal instead of glass. Then a letter was added to
the end to indicate the filiment voltage.

Simiconductors tried the same system. First number the number of
junctions. Not sure about the N and the last numbers were just assigned
in order. Later some even had dots of colored paint on them This was
for the range of gain on them.

Japan tried the same thing with the numbers. One was the number of
junctions. leters for the type, RF , AF.
Many of them left off the starting 2 on them and yu just had to remember
to add that when looking at them.