Approx age from factory markings/approval markings trademarks etc (radio)

Discussions on the equipment used by the Axis forces, apart from the things covered in the other sections. Hosted by Juha Tompuri
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Waleed Y. Majeed
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Re: Approx age from factory markings/approval markings trademarks etc (radio)

Post by Waleed Y. Majeed » 05 Jan 2018 11:17

Hello Funksammler. Not sure if it is aluminium and the stamping seems to be embossed which makes it harder to make on metals unless stamped into from the back of the plate. Dark balelite can also have a shiny metallic look, a bit like blue/black gunmetal or coal. Anyway the "MPA" stamp could (as far as know) only mean it is the "S" type bakelite as mentioned in earlier post.

waleed

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Re: Approx age from factory markings/approval markings trademarks etc (radio)

Post by Vintage-electronics-chopshop » 05 Jan 2018 13:04

Funksammler wrote:Recycled or NOS wartime components can often be found in immediate postwar equipment. The electronics industry was well and truly destroyed at the end of the war so it was a matter of mend and make do... Some of the components appear to be postwar dated however, the NSF capacitor 1948 and the Frako elco 1954 and the blue plastic wrapped capacitor is definitely post war, so unless these appear to be replacements I would say that your piece of equipment is postwar from the mid 1950's. It is perhaps better to post an overall picture as the type of wiring and other components may give further clues. The absence of Wa.A eagle stamps is to be expected, as Flak towers would have been equipped via the Luftwaffe procurement system, so BAL stamps would have been more logical on wartime equipment. This procurement system would also have resulted in an Ln number and the usual wartime coding of the tag plate, absence of which would be another strong indication of a postwar piece of civil defence equipment.

What I find strange is that the bakelite compound code appears to be stamped into aluminium, very unusual or are my eyes deceiving me...?

regards,

Funksammler
Hi, thanks for the info.

I have a feeling some of the caps may have been more modern replacements. The Frako cap looked like a replacement for sure, so that doesnt really surprise me that its from the 50s. The wires connecting it to the rest of the device are clearly more modern.

The other electrolilytics could well have been replaced also. If for example the device was made in the late 30s, by the late 40s they may have already become faulty, and by the 50s its very likely.

So one scenario would be that the device found its way into civilian use after the flak towers were out of service and the war finished, and somebody ended up repairing it in the 1950s with some components in circulation at the time, if you were a electronics shop in 1955 its very possible you had stock from the late 40s.

However another scenario would be that this device was made after the war, was not in a flak tower, and somebody made up a story for it later.

The one thing that i find surprising is the complete lack of wires as we know them. There is not one single plastic/rubber insulated electric wire. Everything is solid copper strand with a wax/laquer soaked cotton outer tube.

By the way that piece is bakelite. Its just the angle of the photo makes it look metallic.

The device is a telefunken ELA409/2 which is an accessory to add powerful loud-speakers to devices which usually use headphones, like communications radios etc. So usually a comms radio would only be heard by the radio operator thru their headset. If you want all the people in the room to hear it, you would plug it into this device and it will power bigger speakers.

The ela409/2 is usually quoted as being a 1938 model, but that doesnt mean its made in 1938, it just means the model was first put on sale in 38.

It looks very 30s styling, big square amp ugly monolith with no features at all. Like a dke38 but without any styling at all.

Maybe the telefunken serial number may help date it? I dont want to post it for the whole world to see yet because the item is still in somebody elses collection (for now, but may be mine soon) and to be polite i try to never post serial numbers of other peoples things, but if anybody thinks they can help i will pm them the serial.

Thanks

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Waleed Y. Majeed
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Re: Approx age from factory markings/approval markings trademarks etc (radio)

Post by Waleed Y. Majeed » 05 Jan 2018 13:22

Please do PM it! Kind of a hobby searching for odd things on the net. Will keep it to myself too, for as long as you wish!

waleed

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Re: Approx age from factory markings/approval markings trademarks etc (radio)

Post by T. A. Gardner » 05 Jan 2018 20:42

Funksammler wrote:What I find strange is that the bakelite compound code appears to be stamped into aluminium, very unusual or are my eyes deceiving me...?

regards,

Funksammler
It probably is just a silver painted finish on it, but it is hard to tell without better views of the whole device.

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Re: Approx age from factory markings/approval markings trademarks etc (radio)

Post by Vintage-electronics-chopshop » 05 Jan 2018 23:36

What I find strange is that the bakelite compound code appears to be stamped into aluminium, very unusual or are my eyes deceiving me...?
Its just normal brown bakelite like a lot of goods of the period. Its just the angle of the photo and the color of the flash makes it look strange like this. Its really a very normal standard material like dke38s and ve301s and a lot of other goods from the time are made from.

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Re: Approx age from factory markings/approval markings trademarks etc (radio)

Post by Funksammler » 06 Jan 2018 16:10

OK, at least I understand what piece of equipment you are talking about now. No problem with it being war-time manufacture, but the Flakturm story becomes a bit suspect. It is a small domestic audio amplifier which enables you to use a more powerful speaker with your Volksempfänger. OK in a domestic setting, but 3 Watt is nowhere enough for a public address system. Couple that to the impossibility of getting domestic radio reception in a reenforced concrete building and the contrast to the sort of heavy duty equipment that was used in Flakturms and other fortifications makes it very unlikely that it was used in the claimed setting.

regards,

Funksammler

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Re: Approx age from factory markings/approval markings trademarks etc (radio)

Post by Vintage-electronics-chopshop » 06 Jan 2018 16:48

Funksammler wrote:OK, at least I understand what piece of equipment you are talking about now. No problem with it being war-time manufacture, but the Flakturm story becomes a bit suspect. It is a small domestic audio amplifier which enables you to use a more powerful speaker with your Volksempfänger. OK in a domestic setting, but 3 Watt is nowhere enough for a public address system. Couple that to the impossibility of getting domestic radio reception in a reenforced concrete building and the contrast to the sort of heavy duty equipment that was used in Flakturms and other fortifications makes it very unlikely that it was used in the claimed setting.

regards,

Funksammler
To be honest i was suspect of the story to begin with. Since i restore a lot of equipment from the period, i hear a lot of stories. People like romantic stories about their items.

There is some evidence to these devices being used in military communication installations etc but like you said 3w is not much power. However as we know, 3 vacuum tube watts is much more than the fake audio watts we use these days. As an experiment, i tried this device connected to 3 post-war high impedance outdoor loudspeakers, and it actually produces enough power for something like a train station or small building. Its actually impressive for such a small amplifier.

I dont mind if its story about being in a flak tower is not provable, however my collection is very small and i have very little space. Any space i have i fill with my engineering equipment, so i mostly dont collect much. I have to choose carefully what to add to my collection because a lot of people offer me things for sale. Cant own it all.

So, Funksammler, if for now we ignore the flak tower story, and just boil it down to the simple question of is this made before may 7th 1945, or after? What is your opinion about this?

Thanks

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Re: Approx age from factory markings/approval markings trademarks etc (radio)

Post by Funksammler » 08 Jan 2018 17:24

Based on what I can see component and wiring wise, I would say post war. This does not rule out that it was a repaired or rebuilt wartime unit or assembled using partly wartime stock. Although plastic wiring could be found in some very late war equipment, the absolute priority was military production at that time, I can't see them building this sort of civilian equipment in late '44 and 45.

regards,

Funksammler

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Re: Approx age from factory markings/approval markings trademarks etc (radio)

Post by Vintage-electronics-chopshop » 09 Jan 2018 00:45

I think the two possibilities that are becoming possible are:

1) built after the war. Possibly with one old-stock wartime capacitor. Possibly i got the s&h dating codes wrong on the big gray 2x 0.5μf.

2) built before the war, then repaired with a selection of random parts after the war. Would explain why it was rebuilt to use a different power tube.

I started looking at serial numbers. It seems on later equipment, the last 2 digits was just the year. So telefunken products from the 60s would have xxxxx 67 for example.

There are any only two other 409/2s that i can find on the internet.

One is on radiomuseum, and is claimed to be 1938, however since i still dont have a radiomuseum login, i cant find out how they dated it.

Assuming that the first 5 digits is an actual serial number and the last digit is the year, that would make the one on radio museum some 50,000 units younger than mine. And its last digit is 9, so i guess that could mean 39.

Im guessing its not actually younger than mine, they just changed the serial number range for the 1940 model year.

The only other one is for sale somewhere. The seller is not saying its age, however its serial number is very close to mine, within a few hundred. And they both seem to have the same odd modification. And both have the same fuse-holders, whereas the one on radio museum has a different design of fuse holders. And both numbers end in 3.

If we think that the last digit 3 means 1943, that would also seem to correlate between the date code on the big gray dual cap, which i think may be spring 1943.

Would they even be making stuff like this in 1943? I know 44/45 was like a total mess for them but was 43 still reasonably normal?

The FRAKO cap doesnt even fit the chassis properly so somebody just stuck that in there for sure. But the two late 1940s electrolytics are odd. If something was made in 1943 you wouldnt think it would need new caps 2 years later.

This device is a damn mystery.

Does anybody know anybody that knows how telefunken serial numbers work?

Thanks

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