TUBE CODES

Hi,
I have some GeAt7 tubes,they are marked 58-39,58-17,4-39 and 5-22,does anyone know what these numbers mean?

yogiboy04-30-2010 8:08pm

yogiboy OP Details Discussions Posts This discussion Message User 5,665 posts 05-01-2010 at 09:15am Copy Comment URL Report Comment Edit Delete Thanks for the information.
mechans Details Discussions Posts This discussion Message User 3,048 posts 05-01-2010 at 12:31am Copy Comment URL Report Comment Edit Delete Check out the code links archived on tube Asylum. Just do a search. The single digits were used by other manufacturers to designate a year during the 1950s. Thus Almarg appears correct the second set seems to mean made in the 39th week of 1954 and the 22 week of 1955. The first two look like JAN codes both tubes 1958 the 17th and 39th week.
almarg Details Discussions Posts This discussion Message User 9,670 posts 04-30-2010 at 11:54pm Copy Comment URL Report Comment Edit Delete The 58-39 most likely means that the tube was manufactured in the 39th week of 1958. Likewise for 58-17. Not sure about 4-39 and 5-22, but perhaps the last two digits of those numbers also refer to the week, and the 4 and 5 also refer to the year, but with the first digit of the particular decade omitted. Regards, -- Al