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Tube Code Question


Active member
Nov 4, 2005
My brothers, I'm trying to determine the manufacturer of a set of 6L6's. There is no logo, just the code OTK 59 and 9908 and 6L6GC, made in Russia. I suspect that they are Svetlana's, but can't be sure, they have brown bases. Anybody?


Well-known member
Feb 27, 2003
I just pulled a brand new Winged C 6L6...SVetlana...out of the box. There is a blue ink-stamped OTK 61 on the tube...separate from the other screening on the tube. That 9908 on your tube is a date code....I would take it to be the 8th week of 1999. The date code...1206....2012, 6th week... on this new tube is screened along with the logo and 'Made in Russia' stamps.
I wouldn't take this for fact...but itis compelling evidence that your guess is correct.