Dating Sets

A common problem is collectors have is establishing how old sets really are. No dating method can ever be exact, apart from referring to records from the time (such as service data publications), because different manufacturers may have taken different periods of time to update their tuning scales or utilise the latest valves. However, looking at all the clues, you should be able to estimate the age of a set fairly accurately.

Various methods are given on this page. Further ideas and amendments will be added when the site is updated. Additions and corrections are welcomed.

There is more information on this subject at Allan's Virtual Radio Museum.

Look out for the following stations marked on the dial

This information was found somewhere on the Internet - but unfortunately I cannot remember where!

Look at the type of valves used

As new types of valve were introduced, manufacturers generally included them in their new models fairly quickly. There is a good two-page spread in the "Radio Radio" book, picturing many of the valve types with dates. The following is a summary of some of this information.

Obviously some manufacturers would have taken longer than other to introduce new devices, so sets may be somewhat newer than this information would suggest. However they couldn't be older!

Look at trends in design

As with other ideas on this page, design trends can be little more than clues to the age of a set. Some manufacturers took longer than others to introduce new ideas. This information is summarised from the book Radio Radio. Further information and corrections are welcomed.

Look at component date markings

The electrolytic capacitors, in particular the main smoothing capacitor, are often marked with manufacture dates. The reason for this is that capacitors required reforming if they had not been used a certain period of time. The date allowed the first user of the capacitor to conform whether or not it needed reforming before applying power.

It is likely that the radio was manufactured a few months after the date on the capacitor, so you could probably assume the set was made in either the same year or the following year to the capacitor date.

However it is possible that the capacitor may have been replaced - and the replacement could be newer or older than the original. Or the capacitor may have been in storage for a longer period before being fitted.

Although not that relevant to most vintage radio equipment, many semiconductor components (in particular ICs) contain a four digit date code. This will probably be below the type number of the part. The first two digits indicate the year, and the second two indicate the week. So a component marked 7123 would have been made in week 23 of 1971.

Decode the model number

Some manufacturers give clues in the model numbers of their products. I will see if I can establish some more of these for future updates to this page. If anyone knows of other model numbers that can be decoded in a meaningful way to establish the date, please let me know.

It should be noted though that many of these manufacturers would happily break their own rules, so this information should be regarded as a clue only.


With some post-war Ferranti sets, the last two digits of the model number, reversed, appear to give the year that the set was released. In some cases the release date shown on the service data is one year later, so the model number may be indicating the design year rather than the release year. For example, models 215 and 615 were both released in 1951.

I don't know how useful and consistent this is though - would anyone care to comment?


Mike Izycky offers the following useful method for dating GEC radios:

GEC sets are very easy to date, with only one or two exceptions. Up to 1949 the first two digits of the model number are the model year. After 1950, the model year is the sum of the first two digits added to the last two digits, so:-

BC5639 = (5+6)+39 = 50, so the set is 1950.

This doesn't work with the later models having three digit numbers though.


With many McMichael table sets, either the first two digits or the last two digits of the model number will be the year. This doesn't seem to work with console sets and radiograms though.

For example, model 371AC was released in 1937, model 493 was released in 1949 and model 153 was made in 1953.

This website, including all text and images not otherwise credited, is copyright © 1997 - 2006 Paul Stenning.
No part of this website may be reproduced in any form without prior written permission from Paul Stenning.
All details are believed to be accurate, but no liability can be accepted for any errors.
The types of equipment discussed on this website may contain high voltages and/or operate at high temperatures.
Appropriate precautions must always be taken to minimise the risk of accidents.

Last updated 14th April 2006.