Ive scored a bunch of these NOS tubes a while back, thinking they were possibly made by mullard blackburn as the crimped glass and etched codes appeared to look the same as blackburn codes, but upon further inspection the codes dont match and seeing smooth plates made me think they looked like telefunken construction.
After googling the codes on some of the tubes (most of them start with 2A1) and end with 06A or 06L, it looks like they are early EI tubes, despite "made in england" stamped on the glass.
If so, im guessing these are pre-war EI tubes from the 1970's?
After googling the codes on some of the tubes (most of them start with 2A1) and end with 06A or 06L, it looks like they are early EI tubes, despite "made in england" stamped on the glass.
If so, im guessing these are pre-war EI tubes from the 1970's?
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Not 100% true, ive seen many Mullard tubes with 12AX7 printed on them, usually these are for export market and usually you see ECC83 beneath.
But your right, Mullard always used Great Britain stamped on them.
However I have seen some rebranded tubes from the 70's that were made in the blackburn factory but would have 12AX7 stamped on them.
Ive seen other millitary ones from Mullard also with CV492/12AX7 out there.
Anyway, im confident these are EI tubes, anyone farmiliar with EI codes?
Im interested to know when they were made.
2A1
06A
is all I can see on the tubes, they dont show up well in the camera also.
On some tubes they are not very readable, but im confident they are very early Ei tubes, which is a good score at $10 each
Im pretty sure the EI tubes used philips tooling for the glass and telefunken for the plates etc, these look exactly like an EI inside, but i am trying to work out the date on these, probably 1970's im guessing.
In the United States, "made in England" was usually ( fraudulently ) affixed to east German or USSR made tubes, possibly other eastern bloc countries, as an end run around legal restrictions.
However, all of the rebranded Ei tubes I have seen are plainly marked "Made in Yugoslavia". Perhaps they were insufficiently communist, or there were other considerations.
That said, I have in my hand a "National" brand, dual marked 12AX7A/ECC83, Made in Yugoslavia, that looks identical to your tube - Phillips style glass, Ei ( Telefunken ) style plates, but all of mine have the dot and semi circle factory code etched on the glass.
I believe your tube is an Ei, for better or worse.
Win W5JAG
However, all of the rebranded Ei tubes I have seen are plainly marked "Made in Yugoslavia". Perhaps they were insufficiently communist, or there were other considerations.
That said, I have in my hand a "National" brand, dual marked 12AX7A/ECC83, Made in Yugoslavia, that looks identical to your tube - Phillips style glass, Ei ( Telefunken ) style plates, but all of mine have the dot and semi circle factory code etched on the glass.
I believe your tube is an Ei, for better or worse.
Win W5JAG
Interesting, ive never seen a single EI tube with their logo etched anywhere, mind you these were all later tubes with it painted on which as usual rubs off easily.
thats an Ei tube!
2A1 ist the Ei factory for ecc83/12ax7 tubes
3A1=ecc81/12at7
a semicircle with a dot is the ei factory code
i newer saw an ei tube code list ,the number 6 can be anything between 1966-86!
A and L are the months i guess
this is from the EI Website:
"Ei RC" operates as a subsidiary of Elektronska Industrija (Ei) Holding Corporation, Niš, Yugoslavia. The factory has been founded in 1951 using Telefunken technology. In 1959 Philips technology had been adapted and production was mainly devoted to the radio and TV tubes. There were 126 tybe types (NOVAL, OCTAL, MAGNOVAL) in production with overall capacity of 12 millions pcs/yr. In the mid eighties this production programme has been abandoned due to the technological obsolence and lack of the market.
dewy1
2A1 ist the Ei factory for ecc83/12ax7 tubes
3A1=ecc81/12at7
a semicircle with a dot is the ei factory code
i newer saw an ei tube code list ,the number 6 can be anything between 1966-86!
A and L are the months i guess
this is from the EI Website:
"Ei RC" operates as a subsidiary of Elektronska Industrija (Ei) Holding Corporation, Niš, Yugoslavia. The factory has been founded in 1951 using Telefunken technology. In 1959 Philips technology had been adapted and production was mainly devoted to the radio and TV tubes. There were 126 tybe types (NOVAL, OCTAL, MAGNOVAL) in production with overall capacity of 12 millions pcs/yr. In the mid eighties this production programme has been abandoned due to the technological obsolence and lack of the market.
dewy1
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