[mlundy57]

I just received a matched quad of Winged C EL 34's. On other tubes I have there is a date on the box, but not on these. The only markings are the Winged C with EL34, Made in Russia, 1150 on the front of the tubes and then off to the side, in what looks almost like a blue stamp is "OTK 61".

Does that mean a 1961 manufacture date? These are NOS tubes.

Thanks,

Mike

[sfox7076]

OTK with a date means it was tested on that date by the government.  I am not sure when they were made and it would seem odd to me that the Winged Cs would be that old.  I think 61 may be the tester.  I don't think 1950 would be possible as a manufacture date as the EL34 was not introduced until 1953.

[FullRangeMan]

I just received a matched quad of Winged C EL 34's. On other tubes I have there is a date on the box, but not on these. The only markings are the Winged C with EL34, Made in Russia, 1150 on the front of the tubes and then off to the side, in what looks almost like a blue stamp is "OTK 61".

Does that mean a 1961 manufacture date? These are NOS tubes.

Thanks,

Mike

OTK is the label of approval at the factory qualiry control test, 61 is the person number that proceed the test.
In case this tube fail in a important mission, the tech that tested the tube in that date will be easily found and punished accordingly.

The diamond <17> is the military test approval label, the 17 is the technician number that performed the test.

1150 is date manufacture November 1950 according Russian date codes.
What other numbers/marks these tubes have?

[mlundy57]

Thanks.

The only other marking is the newly affixed label from ApexMatching.com where the tubes were matched into a quad. Also, the 1150 is not consistent. One tube has 1142, another 1144, and two have 1150. Here are some pics of one of the tubes:







Mike

[FullRangeMan]

Its not usual indeed, these tubes seems follow the western pattern:
11 is a year code I unknow, 42 is the week of the year (52 weeks).
There is any tube marked greater than 52?

[JackD]

I suspect those tubes were made in 2011.  The second two digits are the week of that year.

[mlundy57]

I suspect those tubes were made in 2011.  The second two digits are the week of that year.

These are supposed to be NOS tubes cost $75 each plus shipping

[sfox7076]

http://andrewsamplab.com/blog/?p=196  Does not surprise me...

[JackD]

To some vendors NOS means not being manufactured today.  Sorry!

[mlundy57]

http://andrewsamplab.com/blog/?p=196  Does not surprise me...

Thanks.

I went back to the website where I ordered them and read the description with this new understanding and realized I had misunderstood what I read. The description said they were out of production but did not specifically say they were NOS. I just took out of production to mean NOS. That will teach me to read things more carefully and/or ask better questions. By the way, I was off a little on the price. They didn't cost me $75 ea, they were $87.50 ea plus shipping.

I just got them today and was planning on putting them in my amp for a little while just to make sure they are OK and sound at least as good as the Winged C EL34's I am currently using. If they do fine. If not, they have a return policy.

Thanks, for your help

Mike