DATE CODES FOR RCA-MADE TUBES Ludwell Sibley

Sylvania was probably the most prolific American tube manufacturer, and their tubes were found packaged by many well-known USA name brands. Among the EIA codes that you will find on Sylvania-manufactured tubes are and Here are photographs to illustrate the wide diversity of companies that Sylvania manufactured for…. Please note that these companies distributed tubes by other tube manufacturers also. Notice that Sylvania Chrome-Top tubes will always have a code adjacent to the tube-type. The code consists of three characters, usually but not always in a Letter-Number-Letter sequence. Apparently Sylvania had already silkscreened this tube with their own logo, but subsequently the inventory was purchased by CBS. It is obvious that CBS attempted to remove the Sylvania logo, but under careful light it is still visible. You can easily identify the tube as Sylvania-manufactured.

Identifying Vintage NOS Vacuum Tubes by Brand Country and EIA Code

This second entry is made to show the true designing company and manufacturer company in the s for their common tube brand RCA or RCA Radiotron. In the situation changed and RCA was producing tubes, but not before! Out of the laboratory was to come perhaps the most famous invention of all-a successful development of the incandescent electric lamp.

The RCA Corporation was a major American electronics company, which was founded as the By , RCA had completely switched from tubes to solid-​state devices in In , RCA Global Communications Inc., a division with roots dating back to RCA’s founding, was sold to the MCI Communications Corporation.

RCA logos and boxes. The dates on box flaps show: date on box with circle-RCA as the logo probably the date when this style of box was introduced date on white and red box with RCA letters as the logothis box still says made in USA. It seems like they would since it would be difficult to time running out of the old style boxes. I have some distributor stock many 5-packs, mostly TV and FM tubes and the old style boxes have the new style logo on the tube.

Anyone know for sure that RCA did this? Thanks, Mark. I can offer an educated guess, having worked for a large corporation with thousands of products that required re-labeling when their logo was changed: 1 Lots of raw inventory pre-printed cardboard. Yes, that is what is probably the way it was, before “just-in-time” manufacturing. I am not sure about the date codes on the boxes or anything else, except the letter codes for the dates on the tubes. I found concrete information about that.

I googled the subject and found forum histories with replies from those who actually worked in the industry back then. There were also “service publications” about most everything. Some of them appear on the web from time to time, but nothing about box dates.

6146 Family of Vacuum Tubes

The classic information, on early RCA tubes in particular, is Bro. This page brochure goes into necessarily exhaustive detail on prewar product. Bits of other “dating data” have surfaced in the radiocollector press and are available in, for example, Tube Lore.

Find many great new & used options and get the best deals for Radio tubes Four 6V6 Three RCA and one Tung-sol Early date codes /TV/7 tested at the best.

All Rights Reserved. Built with Volusion. Join our mailing list! When the single character codes were used up, double character codes were introduced. For example, the 6SN7 has two cathodes, two grids, two plates, and a filament. Additional letters: A Controlled heater warmup time, although can also be used to denote increased ratings or performance over and above the non-A model.

C Ditto. G Glass bulb. GT Glass tubular. W Ruggedised version. X Low loss ceramic base.

BRIMAR VALVE TYPE & DATE CODES – HOW TO INTERPRET THEM

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Beautiful set of two RCA 6V6GT vacuum tubes with gray glass. Matched date codes () 77% and 94% Gm as measured on my Amplitrex. 94% tube has.

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DATE CODES FOR RCA-MADE TUBES

Users browsing this forum: devilsmist, Google [Bot] and 6 guests. RCA octagon break date codes. Posted: Sep Fri 02, am. Out of curiosity, I would like to decode the octagon coded dates on these two tubes. Both have breaks in different locations of the upper right corner. One seems to have a break in the top of the right side line and the other seems to not have any breaks in the side lines.

DATING THE RCA (CUNNINGHAM) COMPOSITION- BASE RADIO RECEIVING TUBES FROM MID THRU (START OF WW II) Brother Patrick Dowd.

It looks like you’re new here. If you want to get involved, click one of these buttons! Free Shipping on All Orders! Contact Account Shopping Cart. July edited July in Electronics. All 4 tubes test strong. The RCA on the far left has a 30 degree slanted disk getter. The other 2 RCA’s have disk getters but aren’t slanted as much. I noticed that there is a delta mark on the bottom of the RCA’s and in between the pins there is a “61” tube on the far left “12” 2nd from left “3” 3rd left.

Rca date of manufacture.

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Some of the tubes in circle-RCA boxes have date code DJ (May ). Anyone know for sure that RCA did this? Is there info on the web that I.

Dowd and continue its availability. The following material is limited to the examination and interpretation of the external ‘Company Markings’ on RCA and Cunningham composition-base receiving tubes from mid to the start of WW II. Exception is made in the period prior to April 1st RCA Dating Code , where external physical changes length of tube base, type of pins, etc. The bulk of the information contained in the following pages was gathered from the RCA Standardizing Notices from thru Later Notices were not available at the time this was prepared.

The information gathered had to be combined, condensed and, in a number of cases, interpreted. The material for the period from thru was completed by extrapolating information obtained from the earlier RCA Notices, by making use of data from previous research I had done in this area and by the examination of literally many, many ‘bushels’ of tubes from this period courtesy of Howie Schrader, Gerry Tyne, Bob Morris and Bruce Kelley. In many cases the dates listed are approximate. There are many reasons for this: There is no way of determining the exact time-lapse between the announcement of a change and its implementation.

It is impossible to even guess at the time interval that might exist between manufacture, warehouse storage, labeling and final release.

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