telefunken: 31G; Arcolette - Stabilizator tube designation

Gentlemen,

I have 2 questions relating to the TFK 31G:

Is there a corresponding "Te" or "RR" designation for the regulator tube - or the  3-position wire wound dropping resistor  for this model??

The  second question relates to the possible replacement of the RE134s . . . .would the RENS1374d be acceptable in the output circuit??

Respectfully,
Robert
NOTE: I have read the forum post which discusses the ballast requirements for the TFK 40 model (and the TFK 31G is mentioned) - Kobi reminds the members of the E14 base of the Vorschaltwiderstand!!

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Corresponding to "Telefunken Wekstattbuch (No 1)" the RE134s (RE134 Serie) can be replaced by "RES164d Serie". In this case a screen grid resistor of 50kΩ resp. 20 kΩ resp. 10 kΩ for 220 V resp. 150 V resp. 110 V is necessary. An additional screen grid capacitor of 0.1 μF in parallel to the screen grid resitor is necessary.

RE134s and RES164ds have a filiament current of 150 mA, however RENS1374d has a heater current of 1.1 A. Therefore the RENS1374d cannot be used in the circuitry of T31G Arcolette. Else you have to use an additional 4 V transformer for the heater.

The tapped resistor is given with 150 Ω totally. No additional information can be found for the regulator exept that there were different types for 220 V resp. 150 V resp. 110 V. From the schematic can be seen, that only the filianet current  passes this regulator.

Best regards

Dietmar

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Herr Rudolph,
I apologize for asking such a trivial question about the suitability of the RENS1374d tube. I should have known that a tube which requires a current draw of 1.1 amps could not substitute directly for a tube which requires only 0.15 amps.

Presumably there was no data provided for the "blue, green or red-tipped" regulator lamps with the E14 base - other than replacing the item with a "like item".

Respectfully,
Robert

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Dear gentlemen,

the ballast tube for the 31Ga is a tubular, hydrogen-filled iron wire resistor. Though it looks like a light bulb, it only glows dark red in operation and gets quite hot. This ballast resistor is colour-coded by a blue (110V), green (150V), or red (220V) cap. It is quite hard to obtain, and as far as I know it was only used in a few Telefunken DC sets with battery tubes (S-types for series heating). The voltage designates the operating voltage of the set, not the drop across the ballast tube.

Here´s my suggestion for a replacement:

For an operating voltage of 220V, the drop across the ballast resistor is 183V at a filament current of 150mA. If the plate current is taken into account, which is around 15mA with a RE134, the current through the ballast tube is 135mA.

I use a standard tubular 40W E14 socket light bulb, which draws about 140mA at 180V, and has of course a stabilizing positive temperature coeficient. For fine-tuning of the filament current I switched a resistor of about 3k from the "cold" end of the ballast tube to ground (this is in parallel to all the filaments and the drop resistor of the output tube, 17 volts drop), which allows to drain off any excess current. This resistor can easily be adjusted to work with most 40W light bulbs.

Then I painted the top of the light bulb red ;-)

Now my radio really lights up when I turn it on, but what else can I do unless I find the original ballast tube?

BTW: I´m using a RES164d SERIE output tube with a 50k screen grid resistor. The screen grid cap is, at least in the 31Ga, part of the capacitor block.

Nikolaus Löwe

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Dear colleagues,

I am posting this text for my esteemed friend and member Carlos Landi - he has been having some posting problems.

I shall post in both languages  . . . . . . . . the following text is his direct email to me yesterday afternoon

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Hola.
     Gracias amigo Roberts siempre muy atento Ud. amigo, gracias Dietmar Rudolph por su buena explicacion en el tema ,gracias a Nikolaus Löwe la verdad no sabia de los reemplazos de la Telefunken 31G, en fin ahora se un poco mas al respecto y espero poder conseguir la Valvula para mi Telefunken en fin mil gracias amigo Roberts Sarbell, mis saludos cordiales.
Respetuosamente.
Carlos Landi


I shall attempt to translate as best I can - in English. . . .

Hello.
And, thanks to you Robert, my good friend always - you are very kind.

Also, thanks to Dietmar Rudolph for his good explanation in the subject. . . .then thanks to Nikolaus Löwe for verifying the replacement tubes of the Telefunken 31G, I have better understanding now on this matter; and I hope to be able to obtain the valves for my Telefunken. Many many thanks to my friend Robert

Warm greetings.
Respectfully.
Carlos

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Respectfully,
Robert
And a special "Thanks" to Herr Georg Richter for his editorial assistance. . . . . . . .

PLEASE NOTE: If there is a member who may have some RE034s and RE114s or RE134s tubes who can help Carlos correctly restore his TFK 31GA, he would be most grateful if you could notify him by email.

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Dear Robert

I am working on a 31G Arcolette.

The set was with the RE 134 missing.

Additionally one RE034 was replaced by a Philips A425 serie 67

From an old equivalent tubes replacement list I found the following:

 

RE 134 = B409

RES 164 = B443 serie 150

RE 034 = A425 serie 67

 

Because all tubes are in a series connection a lot of care should be taken to avoid over voltage on any particular component of the link.

One idea is to apply 3.9 volts to the filament and take note of the current of each applicant. (See photo).

With the chosen components on the board, the filament voltage on each was well into the 3.8 – 4.0 volts working range.

 

 

Regards, Jose

 

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• valve selection (66 KB)

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Dear Robert,

If you need a RE134, I have some NOS tubes from Tekade available. Please contact me on my email address.

Regards, Emilio

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Greetings Emilio and Jose,

I apologize for the misunderstanding. . . .I do not need the RE134 tube (or its equivalent). I submitted the initial request 2 years ago to help another individual; and was trying to determine the variants permissible tubes or regulators for his Telefunken 31G Arcolette.

I believe Senor Carlos Landi may have already acquired the proper tubes for his early Telefunken.

Respectfully,

Robert

NOTE: The following translation was submitted by Carlos in the TALK forum, and I began some inquiries to help identify specific items . . . .there was also a very helpful response from Herr Konrad Birkner

Attachments:

• Bocina O parlante (24 kb)

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