Discussion:
How did filaments become 6.3V or 12.6V etc....
(too old to reply)
o***@tubes.com
2017-02-05 21:57:47 UTC
Permalink
How did filaments become 6.3V or 12.6V etc....

I'm questioning the POINT THREE or POINT SIX part of the number.

(Instead of just listing them as 6 volt or 12 volt etc....)

Just curious!
Foxs Mercantile
2017-02-05 22:26:23 UTC
Permalink
Post by o***@tubes.com
How did filaments become 6.3V or 12.6V etc....
I'm questioning the POINT THREE or POINT SIX part of the number.
(Instead of just listing them as 6 volt or 12 volt etc....)
Just curious!
Because Wet cells are 6.3 and 12.6 volts respectively.
--
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wa6fwi
http://www.foxsmercantile.com
Jim Mueller
2017-02-05 22:36:03 UTC
Permalink
Post by Foxs Mercantile
Post by o***@tubes.com
How did filaments become 6.3V or 12.6V etc....
I'm questioning the POINT THREE or POINT SIX part of the number.
(Instead of just listing them as 6 volt or 12 volt etc....)
Just curious!
Because Wet cells are 6.3 and 12.6 volts respectively.
By wet cells he means car batteries. Before car radios, the most common
voltages were 5.0 and 2.5.
--
Jim Mueller ***@nospam.com

To get my real email address, replace wrongname with dadoheadman.
Then replace nospam with fastmail. Lastly, replace com with us.
Peter Wieck
2017-02-06 13:48:58 UTC
Permalink
Post by Jim Mueller
By wet cells he means car batteries. Before car radios, the most common
voltages were 5.0 and 2.5.
Actually, it is a bit more detailed than this. Telegraph systems used Wet Cells (Copper/Zinc/Cupric Sulphide/Acid) to drive their systems. These cells are stable, long-lived, have very limited self-discharge issues and use (relatively) safe and low-cost materials. Along comes telephony, largely using the same technology. And from that long-distance and ultimately repeaters, finally tube-based repeaters. Western Electric, the equipment-maker for Bell adapted their tubes to prevailing available currents - a Gravity Cell of the chemistry they used is a nominal 1.25 V. Which falls nicely into the 2.5/5 pattern.

Now, radio comes along - and the need to bring radio to 'remote locations', using reliable battery power-supplies - not exactly possible with multi-gallon, loose-top wet-cells, and more in the realm of those 'new-fangled' *sealed* lead-acid batteries (the technology was invented in 1859). We owe the transition from 2.5/5/7.5... to the Japanese, who were the first to use 6.3V, in/around 1935/6. The rest is history.

But, any decent tube tester has filament voltages from 0.6 - 117 including Gravity and lead-acid multiples.

http://jimmyauw.com/2010/01/23/cleaning-up-my-hickok-539b-tube-tester/

Not meant to be a lecture - but, sometimes historical details add to the fascination with the hobby.

Peter Wieck
Melrose Park, PA
analogdial
2017-02-06 15:14:32 UTC
Permalink
Post by Peter Wieck
Actually, it is a bit more detailed than this. Telegraph systems used Wet Cells (Copper/Zinc/Cupric Sulphide/Acid) to drive their systems. These cells are stable, long-lived, have very limited self-discharge issues and use (relatively) safe and low-cost materials. Along comes telephony, largely using the same technology. And from that long-distance and ultimately repeaters, finally tube-based repeaters. Western Electric, the equipment-maker for Bell adapted their tubes to prevailing available currents - a Gravity Cell of the chemistry they used is a nominal 1.25 V. Which falls nicely into the 2.5/5 pattern.
Now, radio comes along - and the need to bring radio to 'remote locations', using reliable battery power-supplies - not exactly possible with multi-gallon, loose-top wet-cells, and more in the realm of those 'new-fangled' *sealed* lead-acid batteries (the technology was invented in 1859). We owe the transition from 2.5/5/7.5... to the Japanese, who were the first to use 6.3V, in/around 1935/6. The rest is history.
But, any decent tube tester has filament voltages from 0.6 - 117 including Gravity and lead-acid multiples.
http://jimmyauw.com/2010/01/23/cleaning-up-my-hickok-539b-tube-tester/
Not meant to be a lecture - but, sometimes historical details add to the fascination with the hobby.
Peter Wieck
Melrose Park, PA
That's curious. John Stokes in his "70 years of Radio Tubes and Valves"
says the first claimed 6.3 V tubes were the National Union NY64, NY65,
NY67 and NY68 announced in May, 1931.

Arcturus, Ken Rad and Raytheon marketed the types 236, 237, 238, 239 in
July 1931. Sylvania and RCA announced their 6,3v tubes around the same
time. At least according to Stokes.

Anyway, I'm not trying to start an argument or anything. I don't have
any first hand knowledge of this one way or the other.
Peter Wieck
2017-02-06 16:42:08 UTC
Permalink
Post by analogdial
That's curious. John Stokes in his "70 years of Radio Tubes and Valves"
says the first claimed 6.3 V tubes were the National Union NY64, NY65,
NY67 and NY68 announced in May, 1931.
Arcturus, Ken Rad and Raytheon marketed the types 236, 237, 238, 239 in
July 1931. Sylvania and RCA announced their 6,3v tubes around the same
time. At least according to Stokes.
Anyway, I'm not trying to start an argument or anything. I don't have
any first hand knowledge of this one way or the other.
Not curious at all. And a good point. Let me look into it further. My sources focus primarily on mass-market tubes, specifically the 6A7.

In any case, here is the reference I used:

https://books.google.com/books?id=VHFyngmO95YC&pg=PA112&lpg=PA112&dq=6A7+tube+history&source=bl&ots=9g6H7qQWhj&sig=iQ8DyfO--Jt7hX0tqKsaoGeROlY&hl=en&sa=X&ved=0ahUKEwie-p7R9PvRAhUBSGMKHcgtCwIQ6AEIJTAB#v=onepage&q=6A7%20tube%20history&f=false

Peter Wieck
Melrose Park, PA
analogdial
2017-02-07 00:38:05 UTC
Permalink
Post by Peter Wieck
Post by analogdial
That's curious. John Stokes in his "70 years of Radio Tubes and Valves"
says the first claimed 6.3 V tubes were the National Union NY64, NY65,
NY67 and NY68 announced in May, 1931.
Arcturus, Ken Rad and Raytheon marketed the types 236, 237, 238, 239 in
July 1931. Sylvania and RCA announced their 6,3v tubes around the same
time. At least according to Stokes.
Anyway, I'm not trying to start an argument or anything. I don't have
any first hand knowledge of this one way or the other.
Not curious at all. And a good point. Let me look into it further. My sources focus primarily on mass-market tubes, specifically the 6A7.
https://books.google.com/books?id=VHFyngmO95YC&pg=PA112&lpg=PA112&dq=6A7+tube+history&source=bl&ots=9g6H7qQWhj&sig=iQ8DyfO--Jt7hX0tqKsaoGeROlY&hl=en&sa=X&ved=0ahUKEwie-p7R9PvRAhUBSGMKHcgtCwIQ6AEIJTAB#v=onepage&q=6A7%20tube%20history&f=false
Peter Wieck
Melrose Park, PA
An online reference to the NU tubes is here:

https://books.google.com/books?id=6KJGeYMzNMIC&pg=PA89&lpg=PA89&dq=national+union+type+68&source=bl&ots=t1W3Dz658j&sig=BXH4fT9PvxK6yQpLj9l9hGesCNQ&hl=en&sa=X&ved=0ahUKEwil2d2n3_zRAhXFRSYKHXs1A1IQ6AEILjAD#v=onepage&q=national%20union%20type%2068&f=false
analogdial
2017-02-07 14:55:18 UTC
Permalink
For what it's worth, Ludwell Sibley's book "Tube Lore" gives the same
date, 11-22-34, for both the 2A7 and the 6A7. I think that date is it's
RMA registration.

I found it interesting that Sibley has RCA releasing the 2A7 and 6A7
together. RCA claimed that 2.5V was the optimal heater voltage because
the hum induced by the heater's magnetic field was in opposite phase to
the hum from the heater's electrical field and they would tend to cancel
each other out. Obviously, the non-RCA manufacturers weren't so
concerned and RCA was still interested in selling them tubes.
c***@snyder.on.ca
2017-02-06 17:12:26 UTC
Permalink
On Mon, 6 Feb 2017 15:14:32 -0000 (UTC), analogdial
Post by analogdial
Post by Peter Wieck
Actually, it is a bit more detailed than this. Telegraph systems used Wet Cells (Copper/Zinc/Cupric Sulphide/Acid) to drive their systems. These cells are stable, long-lived, have very limited self-discharge issues and use (relatively) safe and low-cost materials. Along comes telephony, largely using the same technology. And from that long-distance and ultimately repeaters, finally tube-based repeaters. Western Electric, the equipment-maker for Bell adapted their tubes to prevailing available currents - a Gravity Cell of the chemistry they used is a nominal 1.25 V. Which falls nicely into the 2.5/5 pattern.
Now, radio comes along - and the need to bring radio to 'remote locations', using reliable battery power-supplies - not exactly possible with multi-gallon, loose-top wet-cells, and more in the realm of those 'new-fangled' *sealed* lead-acid batteries (the technology was invented in 1859). We owe the transition from 2.5/5/7.5... to the Japanese, who were the first to use 6.3V, in/around 1935/6. The rest is history.
But, any decent tube tester has filament voltages from 0.6 - 117 including Gravity and lead-acid multiples.
http://jimmyauw.com/2010/01/23/cleaning-up-my-hickok-539b-tube-tester/
Not meant to be a lecture - but, sometimes historical details add to the fascination with the hobby.
Peter Wieck
Melrose Park, PA
That's curious. John Stokes in his "70 years of Radio Tubes and Valves"
says the first claimed 6.3 V tubes were the National Union NY64, NY65,
NY67 and NY68 announced in May, 1931.
Arcturus, Ken Rad and Raytheon marketed the types 236, 237, 238, 239 in
July 1931. Sylvania and RCA announced their 6,3v tubes around the same
time. At least according to Stokes.
Anyway, I'm not trying to start an argument or anything. I don't have
any first hand knowledge of this one way or the other.
Perhaps based partly on the "farm radio" nintroducyion of around that
time which used lead acid automotive batteries ans a multivibrator
instead of "A" and "B" dry-cells.
analogdial
2017-02-07 00:53:38 UTC
Permalink
Post by c***@snyder.on.ca
Perhaps based partly on the "farm radio" nintroducyion of around that
time which used lead acid automotive batteries ans a multivibrator
instead of "A" and "B" dry-cells.
There were different types of farm radios. One type was the type you
mention, very much like a car radio. I don't know which one was
introduced first.

I think there was a type which ran directly on a low DC voltage, say 36
volts. I believe that a farmer of the day could also buy similar voltage
light bulbs and electrify his house with batteries and a windcharger.

The farm radio I'm familiar with uses tubes with 2V 60 ma filaments.
Electrically these tubes are similiar to the miniature 1.5V 50 ma heater
tubes. Physically, they are in the large ST bulb.
c***@snyder.on.ca
2017-02-07 03:36:47 UTC
Permalink
On Tue, 7 Feb 2017 00:53:38 -0000 (UTC), analogdial
Post by analogdial
Post by c***@snyder.on.ca
Perhaps based partly on the "farm radio" nintroducyion of around that
time which used lead acid automotive batteries ans a multivibrator
instead of "A" and "B" dry-cells.
There were different types of farm radios. One type was the type you
mention, very much like a car radio. I don't know which one was
introduced first.
I think there was a type which ran directly on a low DC voltage, say 36
volts. I believe that a farmer of the day could also buy similar voltage
light bulbs and electrify his house with batteries and a windcharger.
The farm radio I'm familiar with uses tubes with 2V 60 ma filaments.
Electrically these tubes are similiar to the miniature 1.5V 50 ma heater
tubes. Physically, they are in the large ST bulb.
The a-b battery style came first. The single voltage ones came later.
There were 6 volt and 12 volt ones and I think there were radops made
for the 32 voly Delco-Light systems as well.
Wincharger made "windmill" generators in multiple voltages - starting
at 6 volts - intended to charge radio batteries. - and going up to
Delco-Light compatiuble 32 volt systems.
analogdial
2017-02-07 14:31:51 UTC
Permalink
Post by c***@snyder.on.ca
On Tue, 7 Feb 2017 00:53:38 -0000 (UTC), analogdial
Post by analogdial
Post by c***@snyder.on.ca
Perhaps based partly on the "farm radio" nintroducyion of around that
time which used lead acid automotive batteries ans a multivibrator
instead of "A" and "B" dry-cells.
There were different types of farm radios. One type was the type you
mention, very much like a car radio. I don't know which one was
introduced first.
I think there was a type which ran directly on a low DC voltage, say 36
volts. I believe that a farmer of the day could also buy similar voltage
light bulbs and electrify his house with batteries and a windcharger.
The farm radio I'm familiar with uses tubes with 2V 60 ma filaments.
Electrically these tubes are similiar to the miniature 1.5V 50 ma heater
tubes. Physically, they are in the large ST bulb.
The a-b battery style came first. The single voltage ones came later.
What I don't know is if the battery powered radio with a vibrator
generated B+ supply first appeared as a farm radio or a car radio.

I do know that there were early car radios which were made with 2V
indirectly heated tubes.

Of course, nearly all the 2V indirectly heated tubes were used in AC
powered radios.
Post by c***@snyder.on.ca
There were 6 volt and 12 volt ones and I think there were radops made
for the 32 voly Delco-Light systems as well.
Wincharger made "windmill" generators in multiple voltages - starting
at 6 volts - intended to charge radio batteries. - and going up to
Delco-Light compatiuble 32 volt systems.
As I recall, Zenith was one of the companies selling winchargers, no
doubt anticipating another sale of a Zenith radio.
c***@snyder.on.ca
2017-02-07 19:18:41 UTC
Permalink
On Tue, 7 Feb 2017 14:31:51 -0000 (UTC), analogdial
Post by analogdial
Post by c***@snyder.on.ca
On Tue, 7 Feb 2017 00:53:38 -0000 (UTC), analogdial
Post by analogdial
Post by c***@snyder.on.ca
Perhaps based partly on the "farm radio" nintroducyion of around that
time which used lead acid automotive batteries ans a multivibrator
instead of "A" and "B" dry-cells.
There were different types of farm radios. One type was the type you
mention, very much like a car radio. I don't know which one was
introduced first.
I think there was a type which ran directly on a low DC voltage, say 36
volts. I believe that a farmer of the day could also buy similar voltage
light bulbs and electrify his house with batteries and a windcharger.
The farm radio I'm familiar with uses tubes with 2V 60 ma filaments.
Electrically these tubes are similiar to the miniature 1.5V 50 ma heater
tubes. Physically, they are in the large ST bulb.
The a-b battery style came first. The single voltage ones came later.
What I don't know is if the battery powered radio with a vibrator
generated B+ supply first appeared as a farm radio or a car radio.
I do know that there were early car radios which were made with 2V
indirectly heated tubes.
Of course, nearly all the 2V indirectly heated tubes were used in AC
powered radios.
Post by c***@snyder.on.ca
There were 6 volt and 12 volt ones and I think there were radops made
for the 32 voly Delco-Light systems as well.
Wincharger made "windmill" generators in multiple voltages - starting
at 6 volts - intended to charge radio batteries. - and going up to
Delco-Light compatiuble 32 volt systems.
As I recall, Zenith was one of the companies selling winchargers, no
doubt anticipating another sale of a Zenith radio.
WinCharger was a registered trademark of Zenith - so techniucally
all "winchargers" were Zeniths.
Peter Wieck
2017-02-07 14:18:47 UTC
Permalink
Post by analogdial
Post by c***@snyder.on.ca
Perhaps based partly on the "farm radio" nintroducyion of around that
time which used lead acid automotive batteries ans a multivibrator
instead of "A" and "B" dry-cells.
There were different types of farm radios. One type was the type you
mention, very much like a car radio. I don't know which one was
introduced first.
I think there was a type which ran directly on a low DC voltage, say 36
volts. I believe that a farmer of the day could also buy similar voltage
light bulbs and electrify his house with batteries and a windcharger.
The farm radio I'm familiar with uses tubes with 2V 60 ma filaments.
Electrically these tubes are similiar to the miniature 1.5V 50 ma heater
tubes. Physically, they are in the large ST bulb.
Wind-Chargers ran at a nominal 32V, and up to 2,000 watts. They typically had a governor that altered the vane pitch so as to maintain a steady rotational speed at any wind speed. In 'vintage' dollars, they cost about as much as a 24V, 2,000-watt turbine does today.

Much on one of the largest, and longest-lived, manufacturers here:

http://www.windcharger.org/Wind_Charger/Jacobs_Wind_Electric_Co..html

Now, for some history - look up the traveling radio salesmen who would go into a town, set up a transmitter on a nearby hill, and go into town to sell radios... Coffin tops for the most part. When sold out, they would pull up stakes leaving the townspeople with more-or-less nothing!

Peter Wieck
Melrose Park, PA
o***@gmail.com
2017-02-10 15:24:34 UTC
Permalink
Post by Peter Wieck
Now, for some history - look up the traveling radio salesmen who would go into a town, set up a transmitter on a nearby hill, and go into town to sell radios... Coffin tops for the most part. When sold out, they would pull up stakes leaving the townspeople with more-or-less nothing!
Which set up his cousin who would visit the town the following week selling long-wire AM antenna kits...
Peter Wieck
2017-02-10 19:15:48 UTC
Permalink
Post by o***@gmail.com
Which set up his cousin who would visit the town the following week selling long-wire AM antenna kits...
Or transmitters to the local church or mercantile.

Peter Wieck
Melrose Park, PA

o***@tubes.com
2017-02-06 10:29:52 UTC
Permalink
Post by Foxs Mercantile
Because Wet cells are 6.3 and 12.6 volts respectively.
Ok. That makes sense... Thanks
philo
2017-02-07 03:18:17 UTC
Permalink
Post by Foxs Mercantile
Post by o***@tubes.com
How did filaments become 6.3V or 12.6V etc....
I'm questioning the POINT THREE or POINT SIX part of the number.
(Instead of just listing them as 6 volt or 12 volt etc....)
Just curious!
Because Wet cells are 6.3 and 12.6 volts respectively.
Correct.

In those days radios were typically powered by batteries and the
filaments were powered from a lead acid car battery. The chemistry gives
approx 2.1 volts per cell at full charge which is where those numbers
come from .

Since a radio used a car battery, radio and car parts stores were common.

A power supply would have been very expensive

http://www.antiqueradios.com/forums/viewtopic.php?f=1&t=185078
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