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  #1  
Old 10-02-2017, 08:21 PM
grimer's Avatar
grimer grimer is offline
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Lang radio

Picked up this old radio recently.The only ID on it is Lang Radio.
It has six 01a tubes in it,the only labeled tube socket reads No e517.
No power transformer,but it has a regular looking 2 spade male connector
on the back.The oldest radio I have ever owned was a Radiola with the # 80
rectifier tube.Any here seen one of these? Would like to get it going,
I'm not very familiar with this super old stuff..
https://500px.com/photo/230375029/lang-by-grimer1
https://500px.com/photo/230375031/lang-by-grimer1
https://500px.com/photo/230375035/lang-by-grimer1
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Old 10-02-2017, 10:22 PM
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init4fun init4fun is offline
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Unhappy Post Response

Hello my Friend . Looking at you photos my best guess would be that it was built to operate from 32 volt DC "farm power" since as you noted there is no power transformer . Either that or there was a power unit that was separate from that chassis that is no longer with it . Looking at the tubes and more importantly the transformers and coils underneath it , it looks like a 3 tube "TRF" (Tuned Radio Frequency instead of superhetrodyne) set with 3 stages of AF amps to give enough signal to power one of the horn speakers of the day rather than a set of headphones .

Such sets are usually real simple to get going since there isn't a lot to them , just a daisy chain of RF amps that all get tuned to the desired received frequency and of course the three audio stages to get the signal big enough to drive the speaker . So it needs a speaker , and to provide it with the appropriate voltage(s)* , give it as long of an antenna as you can possibly set up plus another 50 feet , and with a good ground you may just be able to pull in a few of your local AM stations , barring of course the RF noise level in your area . Last time I had an operational TRF set on display it would get the nearest strongest 4 or 5 stations depending on time of day .

* The two power connections only deal kinda throws me , cause those sets , whether 32 volt farm set 110 VAC , had to have at least ;

An "A" supply , this was power to heat the tube's filaments (cathodes) and was usually a 6 volt DC source regulated with a rheostat .

A "B" supply , this was power to the tube's plates (anodes) and was usually anywhere between 45 and 90 volts DC .

And lastly a "C" supply , this was a negative bias voltage applied to the tube's grid that was used to keep the grid about 4 or so volts negative with respect to the cathode .

Now , the kicker here is that I don't see the voltage divider network that would be needed to derive those three voltages from the single two connection power source as seen in the photos . Clearer photos of all the wiring underneath would be helpful in determining exactly how the different needed voltages are gonna get to the tubes .

PS , can anybody else see the little purple frowning emoji at the top of my post here next to where it says "Post Response" ? I did not click on that or intentionally put it there and I can't seem to edit it out ? Is that some kind of software bug or is there some way I can get rid of it ?

Last edited by init4fun; 10-02-2017 at 10:35 PM. Reason: trying to get rid of that damn frowning face ......
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Old 10-03-2017, 12:32 AM
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grimer grimer is offline
<<721 Porthole ????
 
Join Date: Sep 2006
Location: long island,ny
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Thanks for the reply...
This one has me a bit baffled too. I powered the 2 connectors with 30-35 vdc.
The tubes lit up,at least the filaments are good..There is a long black ribbon underneath(looks like it is made of tar) with some taps in it. The lack of other connectors,xformer,vibrator, is why I put up this post.First thing I did was google Lang Radio,but none of the few results looked similar. I will try to get a good pic in the sunlight when I get a moment
Pat
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Old 10-03-2017, 02:34 AM
Titan1a Titan1a is offline
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These types of radios usually used headphones rather than a speaker. A separate amplifier is probably required.
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Old 10-03-2017, 10:04 AM
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Quote:
Originally Posted by Titan1a View Post
These types of radios usually used headphones rather than a speaker. A separate amplifier is probably required.
I've seen plenty of 6 tube TRF sets made to drive speakers....VERY high impedance speakers.
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Old 10-08-2017, 02:44 AM
EdKozk2 EdKozk2 is offline
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Hi Grimer,
Just a guess but, your radio looks to be laid out like a reflex circuit. The amount of audio inter stage transformers and placement look just like a reflex radio. If it is one, that would explain all the 01-A tubes also. A reflex radio has the tubes do double duty. They can carry the audio signal and RF at the same time. David Grimes built radios in the 1920's using the inverse duplex reflex circuit. I happen to have a Bristol Model D reflex radio I repaired a few years ago. Grimes had a factory near NYC. The radio you have should work with a B+ voltage of 45 to 90 on the plates except the detector. The detector may need only +22 volts. Filaments need 4 to 5 volts DC. The radio may not use a C battery. Some of these radio's used a grid resistor of less than 1 meg ohm for the detector to avoid overload and distortion. Like the other poster said, better pictures would help. I'll try and do some checking on the Lang name too. Cool radio anyhow.
Ed
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Old 10-09-2017, 01:01 AM
EdKozk2 EdKozk2 is offline
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Grimer,
Just wanted to mention, I looked up Lang Radio in the Riders Index. There are Lang Radio schematics in volumes 1,2,3,5 and 6. None of the schematics matched your chassis layout. It seems your radio has an early circuit. I did notice that many of the Lang radios were designed to work off the old 110 volt DC power grid. Maybe someone at ARF has seen your Lang Radio.
Ed
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