How to read Russian Date Codes

Zero Cool · 29th August 2007, 01:22 AM

I just got a batch of Russian 6N13S tubes in and i am curious how to ready the date codes.

all the tubes have a roman numeral and then a number V74, IX74, III72 etc. so i am assuming the last two digits are the year and maybe the roman numerals are the month?

Secondly they all have another number OTK2, OTK4, OTK27 etc.

All have a Diamond pattern with the number 30 in it and red dots on the top of the tube.

Lastly there is some writing on some that i cant quite read with the letter B as the first letter and then a number. the number is usually the same or within 1 of the first set of numbers, Meaning if it has a code of xx74 then the number under the B writing would be 75 or 75....hard to explain maybe i can get a photo of it......Only some have that writing.

Zc

JoshK · 29th August 2007, 01:26 AM

No idea as to your primary question, but your guess seem very likely. I read somewhere that OTK was a QC stamp of approval, not sure if that is true, but I've seen this on russian caps and other parts too.

Colt45 · 29th August 2007, 03:49 AM

yep, datecode is ridiculously simple. well its not really a code.. it just has the date stamped on it. V 79 = may 1979

OTK is technical control. like QC passed.

a plain diamond usually means reflektor factory. not sure what the 30 is about.

your writing bit sounds like a re-test. I have some GK-71 where it's stamped with the manufacture date, then they must have been stored for a year or two (too much stock perhaps) then stamped as being retested before being shipped out.

rutubes.com · 30th August 2007, 12:40 AM

all info about Russian tubes and her type you can find here:
1. Symbols and type of Russian Tubes
2. DataSheets Tubes

Andro_BG · 30th August 2007, 10:42 PM

Hi!
Most of the things already said are right, as far as I know. Here are some logos of SU tube factories.
It could be interesting if you could get your tubes photographed I think ;-) The Bulgarian letter (our letters are used in Russia and not only, sorry for the offtopic!) "B" you mention might be a stamp by a military representative ("Voennaya priemka") meaning that this lot complies with the SU military standards for tubes. Soviet tubes with that additional control passed are known to provide better quality

Best regards,
Andrey

29th August 2007, 01:22 AM	#1
Zero Cool Audio Junkie diyAudio Member Join Date: Sep 2004 Location: MN	How to read Russian Date Codes I just got a batch of Russian 6N13S tubes in and i am curious how to ready the date codes. all the tubes have a roman numeral and then a number V74, IX74, III72 etc. so i am assuming the last two digits are the year and maybe the roman numerals are the month? Secondly they all have another number OTK2, OTK4, OTK27 etc. All have a Diamond pattern with the number 30 in it and red dots on the top of the tube. Lastly there is some writing on some that i cant quite read with the letter B as the first letter and then a number. the number is usually the same or within 1 of the first set of numbers, Meaning if it has a code of xx74 then the number under the B writing would be 75 or 75....hard to explain maybe i can get a photo of it......Only some have that writing. Zc

30th August 2007, 12:40 AM	#4
rutubes.com diyAudio Member Join Date: Aug 2007	all info about Russian tubes and her type you can find here: 1. Symbols and type of Russian Tubes 2. DataSheets Tubes __________________ Click here to visit the ruTubes.com

30th August 2007, 10:42 PM	#5
Andro_BG diyAudio Member Join Date: Aug 2007	Hi! Most of the things already said are right, as far as I know. Here are some logos of SU tube factories. It could be interesting if you could get your tubes photographed I think ;-) The Bulgarian letter (our letters are used in Russia and not only, sorry for the offtopic!) "B" you mention might be a stamp by a military representative ("Voennaya priemka") meaning that this lot complies with the SU military standards for tubes. Soviet tubes with that additional control passed are known to provide better quality Best regards, Andrey __________________ Violence is the last refuge of the incompetent. Isaac Asimov

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29th August 2007, 01:26 AM	#2
JoshK diyAudio Member Join Date: May 2004 Location: Toronto, ON	No idea as to your primary question, but your guess seem very likely. I read somewhere that OTK was a QC stamp of approval, not sure if that is true, but I've seen this on russian caps and other parts too.

29th August 2007, 03:49 AM	#3
Colt45 diyAudio Member Join Date: Feb 2002 Location: Canada	yep, datecode is ridiculously simple. well its not really a code.. it just has the date stamped on it. V 79 = may 1979 OTK is technical control. like QC passed. a plain diamond usually means reflektor factory. not sure what the 30 is about. your writing bit sounds like a re-test. I have some GK-71 where it's stamped with the manufacture date, then they must have been stored for a year or two (too much stock perhaps) then stamped as being retested before being shipped out.

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