Brimar Tubes Date Codes

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Brimar Tubes Date Codes

Brimar (BRItish Made American Range) was a part of Standard Telephones and Cables Ltd (STC) and was founded in London as International Western Electric in 1883. From 1925 to mid 1980s the company was owned by ITT of the USA.

There is very little information available on how to read Brimar tube codes, but in general, they are one of the easiest to decipher.

The code consists of multiple sections and usually look like:
4G9/980 (4th week of production in July of 1959, tube type 6060)

BTW, if Brimar labeled tube doesn’t have the date code or it has foreign stamped on the tube, it’s not produced by Brimar, but by some other manufacturer. Many Brimar labeled tubes are actually Soviet made.

Date codes have:

  • The first number is a week of production
  • The second number is a month of production
  • The third is a year
  • / (Slash separator)
  • Tube type

First number – week of production:

  1. week 1 of production month
  2. week 2 of production month
  3. week 3 of production month
  4. week 4 of production month
  5. week 5 of production month

Second letter – month of production:

  • A = January
  • B = February
  • C = March
  • D = April
  • E = May
  • F = June
  • G = July
  • H = August
  • I = September
  • J = October
  • K= November
  • L = December

Third number – year of production:

  1. 1961, 1971
  2. 1962, 1972
  3. 1963, 1973
  4. 1954, 1964
  5. 1955, 1965
  6. 1956, 1966
  7. 1957, 1967
  8. 1958, 1968
  9. 1959, 1969
  10. 1960, 1970

Forth number – tube type:

  • ECC81/12AT7/CV4024 = 160/2160 or 565/1565
  • ECC81/12AT7/CV4024/6060 = 980/3980
  • ECC82/12AU7/CV491/CV4003 = 161/2161 or 571/1571 or 987/3987
  • ECC83/12AX7/CV4004 = 162/2162 or 573/1573 or 574/1574
  • ECC83/12AX7/CV4004/6057 = 977/3977
  • E83CC/12AX7WA/CV4004/6057 = 977/1977
  • ECC88/6DJ8/CV2492/CV2493 = 167/2167 or 910/3910
  • ECC804/6GA8/6/30L2 = 195/2195
  • ECL82/6BM8/6PL12 = 242/2242 or 791/1791
  • EL84/6BQ5/CV2975 = 795/1795
  • EZ90/6X4/CV4005 = 426/1426
  • 5R4G/CV717 = 124/1124
  • ECC32/6SN7GT/CV1988 = 383
  • ECC32/6SN7GTY/CV1988 = 384
  • ECC35/6SL7GT/CV1988 = 379
  • 6V6GT/CV511 = 422/1422
  • KT66/CV1075 = 331
  • 6X5GT = 432/1432
  • 12BH7 = 585/1585

3 digit code shows pre-1960 production, 4 digit code shows that a tube has been produced after 1960. This, combined with the third number can determine exact production year.

Also take a look at Brimar Special Type tubes

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