Brimar Factory Codes

Factory Codes

Some valve/tube manufacturers put a cryptic code on the glass, in addition to the normal valve type and logo etc. The factory code is often etched into the glass, so may remain when the normal printing has been rubbed off. The codes used by Philips/Mullard/Valvo etc. are well documented on the web (for example, see Philips Code List), but there is little information for the codes used by Brimar and other Thorn group brands (such as UK Mazda and later Ediswan).

I have gathered together some Brimar codes here. Some are gleaned from the web - I have tried to give correct attribution. Others are from my own collection - there seem to be lots of Mazda valves around on eBay in the UK at present.

Anyone owning Brimar/Mazda valves will know that their factory codes tend to be harder to read than the Philips ones, and more easily smudged. In many cases the code is less resilient than the normal printing, but there will be times when the code may be the only way of identifying the valve type so a list will hopefully be useful.

Structure of Brimar Codes

The suggestion given here is not my own, but gleaned from the Vintage Amps bulletin board - see the Wed Mar 07, 2007 9.08am post by saros141. A Brimar code consists of two parts. The first part is three characters, number-letter-number, which give the date of manufacture. The last number is the last digit of the year (so this suffers from the same ambiguity as the Philips code). The letter gives the month (A=January etc.), while the first number gives the week within the month. For example, 2C7 is the second week in March 1957 or 1967. However, I have a 6/30L2 (ECC804) which has a date code of 1N8 so are some letters omitted from the month code sequence, or is it more complicated than we think?

The second part is just a number, usually three or four digits long, which gives the valve type. Different versions of a particular valve type will have different numbers, although these may sometimes be grouped together. For example, 1573 and 1574 are types of ECC83 but so is 2162. It is suggested here that four digit codes started in the 1960s.

Between the two parts of the code there may be a slash /, or a space, or nothing at all. Sometimes it is difficult to distinguish a three-digit number preceded by a slash from a four-digit number with no separator, so there is some uncertainty in some of the four-digit codes starting with 1. For example, the code for ECC82 is said to be 1571 (see ref AA1), but I have some which are clearly marked 571. However, I have some 19AQ5 marked 660, and others marked 1660, so perhaps xyz and 1xyz are related (different factory)? Digits 5 and 8 can look quite similar. The code may be horizontal or vertical, and could occur at almost any height on the glass envelope. Sometimes it will be obscured by the normal printing.

Brimar Codes

RefCodeEuUSOtherNotes
DPK 195EBC90 6AT6DH77
DPK 229EK90 6BE6X727
DPK 244 6BR7CV2135 see 979, 8979
VA1 422 6V6GTYCV511
DPK 524 9BW6
DPK 557 12AH8
DPK 571ECC82 12AU7CV491 see also 1571
DPK 585 12BH7? valve is unmarked but looks internally like a 12BH7
DPK 630 CV2212, 13D3similar to CV4068, 6158
DPK 660HL90 19AQ5 150mA version of EL90/6AQ5, see also 1660
DPK977E83CC 12AX7WACV4004, 6057box anode, black, 1 flange, D getter - see 3977
eBay 979 6059 SQ 6BR7, see 244, 8979
DPK1177?EB916AL5 shiny anodes
DPK1175 or 175? 6AK6
DPK1224EF93 6BA6 see 6224
DPK1234EF90 6BH6
DPK1252 6BW6 see 3981
DPK1260EC906C4
DPK1274EL8216CH6CV2127?see 3986
DPK1291PF818/EF8127ED7/6EL730F5/6F2330F5 and 6F23 are very similar, was one a mislabelling?
DPK1294EE80 6F28
DPK1426 or 426?EZ90 6X4
VA11432 6X5GT
VA11565ECC81 12AT7
AA11571ECC82 12AU7CV491, CV4003, 13D4, 13D5, 13D8see also 571
DPK, VA11573ECC83 12AX7CV4004half-boxed-plate
DPK, VA11574ECC83 12AX7 14mm plate
DPK1576 or 1876?ECC804 6GA86/30L2I only have one of these; looks identical to 2195 version.
DPK1660HL90 19AQ5 150mA version of EL90/6AQ5, see also 660
DPK1676PCE8009GB8 30FL2
DPK1681PCC8057EK7 30L15
DPK1682PCC806 30L17
DPK1686PCL801 30PL1
DPK1687PCL80016GK830PL13
DPK1784ECC84 6CW7B319
DPK1791ECL82 6BM8 6PL12 pentode anode grey, staples facing out, no grid tabs, see 2242
DPK, VA11796EL84 6BQ5
DPK1822PL84 15CW5 300mA version of EL86
DPK, VA12160ECC81 12AT7 black wing anode with rounded end
Oth2161ECC82 12AU7 14mm anode (branded Ediswan?)
DPK, VA12162ECC83 12AX7CV400414mm plate
DPK, JR12167ECC88 6DJ8 see also 3910
DPK2195ECC8046GA86/30L2most of my ECC804 have this code
DPK2242ECL82 6BM8 6PL12 pentode anode black, staples facing in, grey heat tabs on control grid posts, see 1791
DPK2510PC97 4FY5
DPK2520PCC84 7AN730L1
DPK2540PCF80 9A830C1
DPK2562PCL84 15DQ8
DPK2563 or 2568? 30PL15
DPK2701KY80 2J2 U26
TC13876 5965
JR13910ECC88 6DJ8 see also 2167
VA1,DPK3977ECC83 12AX7CV4004, 6057box anode, grey, 1 flange, O getter - see 977
DPK3980ECC81 12AT7CV4024, 6060SQ version, black single-flange anode with square end, sometimes triple mica
DPK3981 6BW6 black anode, round getter, double support (see 1252)
DPK3982?QV03/126062 CV4039, SQ 5763
DPK3986 or 3988?EL8216CH6 CV4055see 1274
VA1, Oth3987ECC82 12AU7CV400317mm grey plate, also seen on black half-box plate
DPK6224EF93 6BA6CV454see 1224
DPK8979 6BR7, 6059CV4006, VX7081SQ version? see 244, 979

References

Ref NameRef Location
AA1Audio Asylum bulletin board
DPKMy own collection
JR1Jogis Roehrenbude website
TC1Virtual Valve Museum
VA1 Vintage Amps bulletin board
eBayseen on eBay
Othother sources

Back to audio home, Pinnacle valve P numbers, Valve distortion due to element shape

updated 16 Apr 2012: add donated information