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 a 2007 post on the Vintage Amps bulletin board - which sadly seems to have disappeared. 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

Ref	Code	Eu	US	Other	Notes
DPK	195	EBC90	6AT6	DH77
DPK	229	EK90	6BE6	X727
DPK	244		6BR7	CV2135	see 979, 8979
VA1	422		6V6GTY	CV511
DPK	524		9BW6
DPK	557		12AH8
DPK	571	ECC82	12AU7	CV491	see also 1571
DPK	585		12BH7?		valve is unmarked but looks internally like a 12BH7
DPK	630			CV2212, 13D3	similar to CV4068, 6158
DPK	660	HL90	19AQ5		150mA version of EL90/6AQ5, see also 1660
DPK	977	E83CC	12AX7WA	CV4004, 6057	box anode, black, 1 flange, D getter - see 3977
eBay	979		6059		SQ 6BR7, see 244, 8979
DPK	1177?	EB91	6AL5		shiny anodes
DPK	1175 or 175?		6AK6
DPK	1224	EF93	6BA6		see 6224
DPK	1234	EF90	6BH6
DPK	1252		6BW6		see 3981
DPK	1260	EC90	6C4
DPK	1274	EL821	6CH6	CV2127?	see 3986
DPK	1291	PF818/EF812	7ED7/6EL7	30F5/6F23	30F5 and 6F23 are very similar, was one a mislabelling?
DPK	1294	EE80		6F28
DPK	1426 or 426?	EZ90	6X4
VA1	1432		6X5GT
VA1	1565	ECC81	12AT7
AA1	1571	ECC82	12AU7	CV491, CV4003, 13D4, 13D5, 13D8	see also 571
DPK, VA1	1573	ECC83	12AX7	CV4004	half-boxed-plate
DPK, VA1	1574	ECC83	12AX7		14mm plate
DPK	1576 or 1876?	ECC804	6GA8	6/30L2	I only have one of these; looks identical to 2195 version.
DPK	1660	HL90	19AQ5		150mA version of EL90/6AQ5, see also 660
DPK	1676	PCE800	9GB8	30FL2
DPK	1681	PCC805	7EK7	30L15
DPK	1682	PCC806		30L17
DPK	1686	PCL801		30PL1
DPK	1687	PCL800	16GK8	30PL13
DPK	1784	ECC84	6CW7	B319
DPK	1791	ECL82	6BM8	6PL12	pentode anode grey, staples facing out, no grid tabs, see 2242
DPK, VA1	1796	EL84	6BQ5
DPK	1822	PL84	15CW5		300mA version of EL86
DPK, VA1	2160	ECC81	12AT7		black wing anode with rounded end
Oth	2161	ECC82	12AU7		14mm anode (branded Ediswan?)
DPK, VA1	2162	ECC83	12AX7	CV4004	14mm plate
DPK, JR1	2167	ECC88	6DJ8		see also 3910
DPK	2195	ECC804	6GA8	6/30L2	most of my ECC804 have this code
DPK	2242	ECL82	6BM8	6PL12	pentode anode black, staples facing in, grey heat tabs on control grid posts, see 1791
DPK	2510	PC97	4FY5
DPK	2520	PCC84	7AN7	30L1
DPK	2540	PCF80	9A8	30C1
DPK	2562	PCL84	15DQ8
DPK	2563 or 2568?			30PL15
DPK	2701	KY80	2J2	U26
TC1	3876		5965
JR1	3910	ECC88	6DJ8		see also 2167
VA1,DPK	3977	ECC83	12AX7	CV4004, 6057	box anode, grey, 1 flange, O getter - see 977
DPK	3980	ECC81	12AT7	CV4024, 6060	SQ version, black single-flange anode with square end, sometimes triple mica
DPK	3981		6BW6		black anode, round getter, double support (see 1252)
DPK	3982?	QV03/12	6062	CV4039, SQ 5763
DPK	3986 or 3988?	EL821	6CH6	CV4055	see 1274
VA1, Oth	3987	ECC82	12AU7	CV4003	17mm grey plate, also seen on black half-box plate
DPK	6224	EF93	6BA6	CV454	see 1224
DPK	8979		6BR7, 6059	CV4006, VX7081	SQ version? see 244, 979

References

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updated 22 Aug 2018: modified for new website, note that Vintage Amps board has gone