Talk:List of vacuum tubes

CV numbering system
What 'CV' stands for has been done to death elsewhere.

When the CV numbering system was first introduced somewhere around the second world war, the letters 'CV' did originally stand for 'common valve'. However, after the war, the services decided that they wanted to distinguish between valves that were designed by commercial companies and valves that were designed 'in house' by government research and development establishments. Thus, three designators came into use. 'CV' which now meant 'civilian valve' identifying valves designed by civilian companies. 'E' which designated experimental valves. 'M' for 'military' designating government designed valves (usually starting development as an 'E'). Many fan sites still quote some of the older reference material with the (now) incorrect 'common valve' meaning of CV.

Ordinary valves such as the EF80 were given a CV designation (in this case CV1376) for ease of keeping an inventory of stock. Where a civilian company developed a special quality valve such as the E80F (developed from the ordinary EF80 - though not interchangeable with it) then such a valve gets a CV number (in this case CV2729). There is a popular myth that special quality valves always have a 4000 series CV number. It became the case after unified part numbering schemes were introduced, but not before.

Where a government R&D establishment designs a valve it gets (initially) an 'E' designation and then an 'M' designation. One such example is the M8083. When this was placed with Mullard for production, Mullard also produced a non special quality version for general use, and this was given the Mullard-Philips designation 'EF91'. The EF91 was adopted by the services for non critical applications and became the CV138. America too adopted the design as the 6AM6. America aslo adopted the M8083 as their 6064.

The waters were severely muddied when each service decided to adopt a unified part numbering scheme (that is: unified to each service not across srvices). There was an inevitable overlap of the CV numbering and the M numbering. Accordingly, it was decided that every M valve would be given a CV number. The M8083 was given the alternate number CV4014. This then allowed each service that used the valve to give it their own unified part number. The example that I have in front of me has 'AM REF 10CV4014' on the end of the box (AM is 'Air Ministry', the other two services had their own schemes). The valve inside is marked with both the M and the CV number (non M valves are only marked with the CV number). Eventually, when all three services were combined under the Ministry of Defence, they adopted the NATO wide part numbering scheme and the above valve would be given the stock number 5960-99-000-4014, the last 4 digits being the CV number. Semiconductors were also included in the scheme, services semiconductors being marked with a CV number and given the appropriate Nato stock number. Thus Nato stock number 5960-99-000-7040 is a CV7040 which is a silicon rectifier diode.

I spent most of my working life with services parts and numbering schemes. I still have a fully functional valve sine wave oscillator with 1 CV4033 and 2 M8083/CV4014valves.

Too long
Is this a list or an article about tube nomenclature? Suggest split out the various tube lists to separate lists, and move the nomenclature descriptions to "tube numbering systems". We love parts lists on Wikipedia, we do. --Wtshymanski (talk) 16:50, 22 January 2018 (UTC)
 * Examples of number systems should have one or two entries, not a dozen. The interested reader will catch on after one or two, and most will just glaze over after more than 2 or 3 repetitions. --Wtshymanski (talk) 17:01, 22 January 2018 (UTC)

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What about the 572B / T160L ?
Nei1 (talk) 22:24, 14 December 2021 (UTC)