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Dating models and dating tubes - radio seasons

Ernst Erb Jacob Roschy Martin Renz Bernhard Nagel 
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Forum » Valves / tubes - Semiconductors » Valves / Tubes; practical use and procurement » Dating models and dating tubes - radio seasons
Ernst Erb
Ernst Erb
CH  Articles: 5653
Schem.: 13753
Pict.: 30965
31.Oct.10 18:16

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Since years we have implemented a unique method to be warned if a model is entered with a too early year. We had this on the model admin basis - by having noted a date of "Year of first mass production" for the tubes and for radio models we try to find the right model season.

Often the model year is not the year given by the manufacturer - which wants to show "the next year" where it is often only sold out ... For giving the true situation, we have the "from" year field and the "to" year field. The "from year" indicates the first year of sale, the "to year" indicates the last year sold. An Example is this Kadette K-1149 which is regarded as 1938 model (see the ad) but in fact was sold 1937/38. Normally it is a season from about mid "from year" to mid "to year". There are exceptions where a model was sold only during a part of one calendar year. Measuring equipment, record players etc. were sold most often for several years.

Since October 2010 we have now programs to compare when showing a model. The system looks up the tube tables for the tube dates and brings a red warning on the tube page if the model is dated before the date of (one or some) tubes. On the main tube page we have also a link which shows the cases of incorrect model dating or incorrect tube(s) or semiconductors. When beginning, this list showed not one percent of the model pages - but it is still annoying that we showed 1686 such incorrect model pages. To get rid of this is everything else than simple. At the end of that list you can read in detail why.

Here I give just the summary - which was posted first on a thread to a given model:

1 The model date is incorrect (too early):
 This is mostly the case because collectors want to see their set as old as possible ...

2 The tube date is incorrect (too late):
 Only a tube admin can put in dates and only the superadmin can change a given date.

3 Sometimes schematics etc. show later tubes, not the original tube line up:
Typical example USA: 1929 the UY-224 (224) is introduced.
 1932 this tube is updated with a shoulder-type envelope and is called 24A.
4 The model has multiple versions with changes in the tube line up:
 Very rare cases. 

5 Incorrect tubes were reported from a set that had been modified to use different tubes than
 the original tube line up.

This all has to be counted for if we decide the action which should be taken.
A detailed instruction follows below the list of incorrect dating - which can be sorted in different ways.

You also find the list of tubes which have been dated (yet only 1842) and a list of such semiconductors. We need more input from primary sources.

After having done this job (and in parallel) we should try to rename tubes for many models where we were misguided. We should give the models really the original tube line up.

There is also a later project to unify in some way the different envelope types like 6V6 6V6GT and 6V6G. At the moment we have for this example of the 6V6 in total 1365 models using it, for 6V6G there are 1683 and for 6V6GT are 2799 - not to forget the few 6V6GTA and all others we get by searching for 6V6.

To most collectors this might sound silly, I know. But we try to be (later) a real reference work.
See also how we could bring in very useful information to each model by looking to one example. This forum article about RCA 621TS repair and restoration sticks to the model and can be accessed by the forum or the model. Many collectors have helped beforehand and it would be beneficial for all, the two sites and the collectors (to get more information) to put a link here and there. I asked Alan Voorhees and will wait first for his decision. Surely this will not be used much because it is quite some work to compose a summary.

I know that only very caring collectors will work for building up a reference work (not only a catalog). In the last few weeks some active members from the USA joined - like Alan Douglas (author of books) and Alan Larsen - and others. I hope by reading all this, some more active members will join - or guests send us information using the contact form.

The next page shall show the present situation - in the hope that in one year this is all cleared up.

This article was edited 06.Aug.11 08:55 by Ernst Erb .

Ernst Erb
Ernst Erb
CH  Articles: 5653
Schem.: 13753
Pict.: 30965
31.Oct.10 19:12

Count of Thanks: 4
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Most of the mentioned incorrect specifications fortunately derive from point 3, "Sometimes schematics etc. show later tubes, not the original tube line up."

I used the sort on the list of the 1686 cases to sort by tube - and I extract here the most important:

01A with 222 cases.
You can see on the tube page that this is the UX201A from August 1925 which replaced the earlier UV201A. In 1932, the UX201A received probably a faster heater and a dome shape glass envelope (shoulder-type envelope) and was then called 01A. This is naturally not reflected in the "Saga of Vacuum tubes" by Gerald F.J. Tyne because he ended his big work in the 1920s, writing: "present essential facts to assist in the identification of such tubes made prior to 1930."

Rider's schematics on the contrary can describe already in volume 1, which covers the years up to 1931, an Atwater Kent model 9 and model 12 from 1923 with tubes '01A - when those should have been UV201A! Also Beitman is no help here.

The UX201A was also called 201A - but should not be used this way to not create confusion with the same tube designation made by Western Electric, Myers and Star Tube. The whole family of the UV201 and its direct replacements is covered in this article here by Konrad Birkner (2006).

We have to know that the habit to call tubes with only two digits (if necessary plus a character) was at least already common in 1930. You will see that in "Radio News" from 1930 - but even in 1931 you will find no trace of any shoulder-type envelopes (dome-shaped bulb) on tubes.

For such tubes we have to change for "reason 3" it would be good that we enter the following at the model page:

<br /><br />
See more about <a href="h  ttp://w  w" target="_blank"> dating this model and naming the tubes</a> here
. We try to show the original tube line up, not the later replacement tubes found at some schematics etc.

Since here direct links are not allowed, nor too long terms, exploding the design, I had to put in blanks in front of "radiomuseum" and after "/forum", but in principle you can copy this and adapt. This would inform newcomers about how we treat the model years and the tube line up.

This article was edited 03.Nov.10 22:30 by Ernst Erb .