The last box to your right is identical to the first box of the ECG line. The two boxes in the middle are shown with the top flap up. Other than the flap, the design is identical except the older is flat while the newer is glossy. Writing color was usually yellow, occasionally red sometimes the red appeared more like orange and is given as such in the tube lists , and more rarely green. If the tube writing was red, then the box flap tube type writing was usually red. If the tube writing was yellow or any other color, flap writing was usually black. The Sylvania tube writing scheme was similar to GE's method - see table below.
Dating sylvania tubes
I have a bunch of Computer grade Sylvania 's made for the Buroughs Corp. All have manufacturer codes and a date code of on them.
Dating (69,) 69, results found. 0 1 3 5 10 20 30+. Jul 08, In my opinion, that's a great tube for a Vibro Champ. I tried several different vintage types, including RCA, Tung-Sol, CBS-Hytron, and Sylvania, and a Sylvania like that one was what I ended up with in there. Of course it depends on the current draw and the like, but I really like those Sylvanias for that application. Unbeatable prices on thousands of guaranteed vacuum tubes for sale, vintage NOS hi-fi audio tubes, radio tubes, ham and industrial ready to ship. The only NOS valve dealer with a real webstore. We carry everything from NOS RCA 6L6GC black plates to JJ 12AX7s. We carry brands like Western Electric, Mullard, Telefunken, Sovtek, JJ, Electro-Harmonix, Genalex and .
How would you read this. These tubes I'm guessing are from the 60's.
Hope you can help. Thanks, John. Posted: Nov Thu 09, pm.
If they are 60's, then the date code represents the 39th week of The 1st number is the year, the next 2 numbers are the week.
I've searched the Web for a key to Sylvania date codes, but no luck.
Most other manufactures can be found, but couldn't find Sylvania. Anyone have a source? As for the OP code ofcould be the 39th week of ?
Identifying Vintage NOS Vacuum Tubes by Brand Country and EIA Code
While the codes are usually at the bottom, we have seen these codes in other places like the bottom of the base. Euro codes usually have two lines, the first consisting of 3 or 4 digits and the second almost always having just three digits.
G24517 - Sylvania Original 7E7 Vacuum Tube
Much can be deciphered from these codes but that's for another article. All we are concerned with here is the Manufacturer code.
The Manufacturer code is always the first symbol on the second line. Since "b" is the code for Mullard, made in Blackburn England, you know the tube was made by Mullard. In that case, the next best thing is to identify where the tubes was made.
Following are two full Sylvania tube manuals. Unfortunately Sylvania didn't put data sheets on separate pages - they run together - so it's hard to break up the data into individual files and index them, like the HB-3 data set is. So I just broke the manual up into several parts. You'll have to look to see if the data you want is in there. The "hole" in the top mica identifies these USA made tubes from the TUNG-SOL factory in Newark, New Jersey, USA in the 's. THE UNITED-ELECTRIC RELABEL CODE IS MEANINGLESS AS THEY SIMPLY RELABELED NEW OLD STOCK TUBES FROM TUNG-SOL. RCA, SYLVANIA, AND OTHERS. NO ONE MADE D-GETTER OR SQUARE-GETTER . "FACTS ABOUT SYLVANIA TUBES; IN A BOOKLET entitled Business Facts about Sylvania Radio Tubes, we find the following four reasons why the tubes identified by the "Flashing S on a Green Oak Leaf" are good tubes. First: Sylvania precision operations are handled by men trained for years. And we never rush them, because if you crack a whip over.
Many tubes have a printed country of origin on them. In many cases this is incorrect. If a tube has both USA and another country printed on it, you have to do some further investigation. As noted before, European tube print was made with a chalky substance and is easily identifiable and rubbed off.
If the tube has no codes but says "Germany" there are only a handful of manufacturers it could be. Many but not all European tubes will briefly flash a bright white light when they are switched on.
For some reason, it's quite common to find Soviet era Russian tubes marked made in Germany, England, Holland etc. Russian tubes tend to have distinct mica spacers and are slightly skinnier than US tubes but the biggest giveaway is the getter. If you see this type of getter, there is no doubt it's a less valuable Russian tube even if it's a Telefunken labeled West Germany.
This is not true, many companies used it. GE used an etched dot system to mark their tubes. If you see these dots, you know you have a GE tube.
JAN Military tubes available here. Large selection in stock and ready to ship! Due to Coronavirus (COVID) we have limited staff working on location. JAN-Sylvania 6DJ8 (1 Review) USD $? Each. JAN-Philips 6L6WGB (1 Review) USD $? Each. JAN-Philips 6U8A No Reviews yet. USD $? Each. JAN-GE 6X4WA (1 Review) USD $?9. 19z T R S H U x Y K V On Government tubes, the "E" was printed separately, typically below the date code. Private-brand tubes generally used a shippingdate code of two or three characters. An initial letter (A through L, including I) gives month, followed by the last digit of year. Bulk-packed (OEM) tubes also carried an "E"; File Size: KB. This article provides examples of NATIONAL UNION-manufactured tubes. NATIONAL UNION was another quality USA tube manufacturer with most production dating from s to s. Their production numbers were significantly smaller than the big name brands (RCA, Sylvania, GE). The NATIONAL UNION (EIA) code number is "?. Here is an example.
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If the tubes have square or "D" getters, they would be early production 39th week of , but if they have halo getters, 39th week of The 3 letter Sylvania markings are not date codes. They are production lot codes.
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A good example is Loctal tubes. Only Sylvania and National Union had the equipment to make them. Despite what a tube has printed, they were made by one of the two companies only. They had a contract with a large company to print their logos on the tubes.
It was in the interest of companies like DuMont, Admiral, Emerson etc to have their own logos on the tubes that they supplied in their equipment.
They did this in hopes that when a tube failed the customer would order a tube with the same brand as their equipment at a markup so the company would profit.