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very old tube type 12A data wanted.




 
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Author Topic: very old tube type 12A data wanted.  (Read 282 times)
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Patrick J. / KD5OEI
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« on: February 03, 2019, 12:04:20 PM »

Does anyone have the full data sheet for the type 12A tube? If it is a version of the 12, It has a 1.1V filament and is identical to the 11, except the base. It is not the same as the 112A, which has a 5V filament.

I find the 12 only in the chart section of the RC10 and RC11 manuals. Did not find the 12A. It's not in the JEDEC documents, except for a revision of interelectrode capacitance and nothing else.

Found the 12A, 112A listed on the same line in the sylvania manual under obsolete types. That one is a 5V tube. Shows it running on 90-135V, which seems a stretch for a 32V radio set.


I'm trying to get my grandfather's old Crescentdyne 32 Volt AM radio working.
Crescentdyne Radio Manufacturing Co. Minneapolis, Minnesota.
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« Reply #1 on: February 03, 2019, 12:12:16 PM »

here  https://www.radiomuseum.org/tubes/tube_12a.html  are data of the 12A. But they say it has a 5 V filament.
the 12  https://www.radiomuseum.org/tubes/tube_12.html  has a 1 Volt filament
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Tom WA3KLR
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« Reply #2 on: February 03, 2019, 12:28:50 PM »

Attached is a pdf of a page from my 1943 Sylvania tube manual.  It is 5 volts filament.

Ludwell Sibley's 'Tube Lore' states it is also known as the UX-112A.  On a later page under the UX-112A, "power triode similar to the 71A developed from Westinghouse prototype WL-112; fil 5.0 V @ 250 ma., u 8.5, gm 1.8 mS.

* sylvania1943 12A.pdf (786.65 KB - downloaded 13 times.)
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« Reply #3 on: February 03, 2019, 12:39:18 PM »

The Sylvania data there looks like it. The radio has a 8-10" speaker, but maybe there are two in push pull. 32 Volts? maybe zero bias. Well, on to the investigation. Have not found the schematic for the radio yet. A lot of this old farm stuff information has been lost. Granddad had a farm, and a windmill for pumping water. Not sure how he got the 32V batteries charged, might have been a generator that was long gone.
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« Reply #4 on: February 03, 2019, 01:30:24 PM »

The HV batteries were normally dry batteries and no rechargeable. The filament of 1 V tubes as well. Filaments with larger voltages were  normally lead acid batteries and the voltage was adjustable in the radio with a variable resistor.
Any idea of the year of manufacturing?
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« Reply #5 on: February 03, 2019, 02:11:23 PM »



My father would hitch up the wagon and go to town with the batts.  The garage/ auto dealership/ farm supply would charge the batts.

KLC
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« Reply #6 on: February 03, 2019, 11:17:16 PM »

Universally 32-Volt farm sets were operated off the bank of lead-acid cells, supplying lighting as well.  The battery was kept up by a engine-driven DC generator or more often, a Wincharger:

https://www.youtube.com/watch?v=FpeYLPcUBWA

Most farm radios developed B+ via vibrators, others employed dynamotors.

The 12 and WD-12 tubes were very early triodes, found in many RCA and Westinghouse receivers.  Not the same animal as the UX-112A, but similar to the UV-199.  https://www.radiomuseum.org/tubes/tube_12.html

A successful sub is a type 30.

73DG
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« Reply #7 on: February 03, 2019, 11:43:52 PM »

No specific data and no model number on the set. I am almost sure it says "cresentdyne" but it may be "cresentyne", the info is very faded. It's a single tuner TRF set.

I did a bunch of digging on the web about the set itself today looking for pictures and tech data. The brand of set was mentioned in a 1933 article on sales+service business opportunities as a candidate for replacement, so it may have been 'obsolete' then even with many happy users.

A similar looking chassis was dated 1927. Crescent Radio Manufacturing Co. was apparently a small company, and in those old days, things like schematics and specifications didn't always make it from the many small companies to the industry publishers. I guess mid 1920s.

It is similar to the "M" series from Crescent. All the Crescent radios found so far are listed as 67.5V B+ and 6V "A" battery. That's different than 36V, which may be in error, might have been 32VDC in reality as more common farm voltage? The power requirement was verbally related to me and the set had not been used for 70+ years. No one ever mentioned A and B batteries either, so it was probably all forgotten.

Probably have to remove the chassis and draw the schematic myself. Not used to TRF designs or anything this old but if I can tell the ancient resistors from inductors and /or capacitors and rely on the tube pin-outs then it should not be hard. To me it seems weird that all the tubes are the same, but the 12A is listed as a detector and as an amplifier.

I can try to post a picture, the set got moved behind a pile of stuff, man what a mess I have.

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« Reply #8 on: February 04, 2019, 03:56:23 PM »

This sure sounds like one of the early battery sets ca. 1925-1928, not a 32V farm radio. I've seen '12A tubes used in some of these early sets, so given the 1927 date that you have, the chances are that it is a '12A tube. The A and B voltages you found sound about right for an early battery set.

Your best bet is to inquire over at the Antique Radio Forum. There are some real experts over there on those early sets. I'll bet someone there will be able to identify your set and maybe even supply a schematic.
http://www.antiqueradios.com/forums/index.php

Those were the Wild West days for the radio industry, with lots of small manufacturers that are forgotten today. A lot got wiped out when the more complicated superhets entered the picture and when the Depression killed a lot of small businesses.
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