Small tubes were popular in Hand Transceivers and all
sorts of stuff. Battery radios had them. Typically they
drew lower current on the filaments (heaters) and had them
on one battery. B+ was on another battery.

Tubes are on the upswing and there are a number of makers
for high end audio and high end power amps for transmitters.

I have a number of various tubes here. Some monsters that Iggy
would use or Gunner.

Martin

On 8/19/2015 1:13 PM, wrote:
On Wed, 19 Aug 2015 08:39:36 -0700, Larry Jaques
wrote:

On Tue, 18 Aug 2015 10:24:47 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Larry Jaques fired this volley in
:

It seems
that DARPA is hot for vacuum tubes.


Without even reading it, I can understand why. Tubes are VERY immune to
EMF damage, while semiconductors seem to just belly-up and die at the least
excuse.

Good point. I hadn't thought about it from that aspect. Some muzzy
moron is surely going to set off an EMP bomb around the world
somewhere soon, so the quicker we find ways around it, the better. "We
live in 800AD, and so should you."
I was looking at some kits for making small pre-amps or amps for MP3
players that use very small tubes. I don't know much about how tubes
work. I know the basics but I don't know how the actual size of the
tube internals and their proximity to the other elements inside the
tube affects the operation of the tube. I imagine that today with
modern automation equipment that tubes could be made very small
indeed. Whether the tubes would operate the same as larger ones I have
no idea about but would like to know. I have seen pictures of devices
made and used in WWII that contained very small tubes that were used
in anti-aircraft shells to iniate the explosion when the shell was
close enough to an airplane. These tubes were essentially hand made
and even though tubes seem to me to be delicate these had to be made
to survive the acceleration of the anti-aircraft shell when fired from
a cannon.
Eric

On Wed, 19 Aug 2015 22:43:23 -0500, Martin Eastburn
wrote:

Small tubes were popular in Hand Transceivers and all
sorts of stuff. Battery radios had them. Typically they
drew lower current on the filaments (heaters) and had them
on one battery. B+ was on another battery.

I got rid of my 1T4's just a few years ago. That was 1.5V filament,
and the B+ was 45V, IIRC, which was an Eveready about the size of a
pack of cigarettes. My first shortwave radio used them -- a one-tube
regen that would run for a long time on the 45V and a D-cell.

The US military was developing a new "vacuum tube" configuration, for
the sake of their higher (but not total) EMP resistance, around 15
years ago. They were ganged in groups, with the "tubes" being cavities
cut in blocks of some kind of ceramic.



Tubes are on the upswing and there are a number of makers
for high end audio and high end power amps for transmitters.

I have a number of various tubes here. Some monsters that Iggy
would use or Gunner.

Martin

On 8/19/2015 1:13 PM, wrote:
On Wed, 19 Aug 2015 08:39:36 -0700, Larry Jaques
wrote:

On Tue, 18 Aug 2015 10:24:47 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Larry Jaques fired this volley in
:

It seems
that DARPA is hot for vacuum tubes.


Without even reading it, I can understand why. Tubes are VERY immune to
EMF damage, while semiconductors seem to just belly-up and die at the least
excuse.

Good point. I hadn't thought about it from that aspect. Some muzzy
moron is surely going to set off an EMP bomb around the world
somewhere soon, so the quicker we find ways around it, the better. "We
live in 800AD, and so should you."
I was looking at some kits for making small pre-amps or amps for MP3
players that use very small tubes. I don't know much about how tubes
work. I know the basics but I don't know how the actual size of the
tube internals and their proximity to the other elements inside the
tube affects the operation of the tube. I imagine that today with
modern automation equipment that tubes could be made very small
indeed. Whether the tubes would operate the same as larger ones I have
no idea about but would like to know. I have seen pictures of devices
made and used in WWII that contained very small tubes that were used
in anti-aircraft shells to iniate the explosion when the shell was
close enough to an airplane. These tubes were essentially hand made
and even though tubes seem to me to be delicate these had to be made
to survive the acceleration of the anti-aircraft shell when fired from
a cannon.
Eric

"Larry Jaques" wrote in message
...
On Wed, 19 Aug 2015 20:12:40 -0400, wrote:

On Tue, 18 Aug 2015 09:04:22 +0700, John B.
wrote:

On Mon, 17 Aug 2015 06:09:53 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Tom Gardner fired this volley in
news:mqrt5r$90r$1
:

I have to replace my dual cap every 2 years, why don't they
last?

I used to think it was "poor quality work", but I believe now that
it's a
combination of the impact of "controlled substances" (like PCBs)
and
deliberate planned-life designs.

Keep in mind that such caps are NOT considered a "user replacable
part",
so if the electrical components industry can convince the end-user
"that's just the life of the part", then both the parts makers and
the
local service companies benefit by getting more work.

When you add to that scheme the fact that the _right_ materials
for
building a good (and compact) capacitor are mostly all illegal
now, it
all seems to make sense.

And yes, they could still make good caps for military and high-end
commercial gear, but they usually MUCH larger, and might not fit
in
equipment designed for the smaller form-factor parts. (plus the
exhorbitant prices)

LLoyd

There was an article, a couple of years ago, about substandard
capacitors being used in computer mother boards as they were much
cheaper. The article stated that a couple of engineers had left a
major capacitor making company and set up their own company aimed
at
selling capacitors at a lower cost and left out some sort of
preservative in their capacitors. Whether true or not the latest
mother board I've bought had a statement on the box that it had
"improved, long life capacitors".
second son has built himself what ammounts to a "jumbotron" of 22"
monitors, simply by replacing caps in the power supply of out of
warranty units. He designed a replacement set of caps then bought in
bulk quantity.

Cool. Got a list of those caps?

http://www.badcaps.net/

"Ed Huntress" wrote in message
...
On Wed, 19 Aug 2015 22:43:23 -0500, Martin Eastburn
wrote:

Small tubes were popular in Hand Transceivers and all
sorts of stuff. Battery radios had them. Typically they
drew lower current on the filaments (heaters) and had them
on one battery. B+ was on another battery.

I got rid of my 1T4's just a few years ago. That was 1.5V filament,
and the B+ was 45V, IIRC, which was an Eveready about the size of a
pack of cigarettes. My first shortwave radio used them -- a one-tube
regen that would run for a long time on the 45V and a D-cell.

The US military was developing a new "vacuum tube" configuration,
for
the sake of their higher (but not total) EMP resistance, around 15
years ago. They were ganged in groups, with the "tubes" being
cavities
cut in blocks of some kind of ceramic.

In the early 90's I dreamed up an alien sci-fi technology that had
never invented transistors, instead they made repairable integrated
tube circuits for their spacecraft by soldering the elements onto a
printed substrate in a large chamber ventilated to space. When the
gain decreased they repainted all the cathodes with Caesium or Radium
in an Argon glove box.

I mentioned the idea to an engineer at work (Mitre) who told me about
ongoing research in that direction.
http://science.dodlive.mil/2013/12/0...ps-meet-tubes/

-jsw

On Thu, 20 Aug 2015 07:29:54 -0400, "Jim Wilkins"
wrote:

"Ed Huntress" wrote in message
.. .
On Wed, 19 Aug 2015 22:43:23 -0500, Martin Eastburn
wrote:

Small tubes were popular in Hand Transceivers and all
sorts of stuff. Battery radios had them. Typically they
drew lower current on the filaments (heaters) and had them
on one battery. B+ was on another battery.

I got rid of my 1T4's just a few years ago. That was 1.5V filament,
and the B+ was 45V, IIRC, which was an Eveready about the size of a
pack of cigarettes. My first shortwave radio used them -- a one-tube
regen that would run for a long time on the 45V and a D-cell.

The US military was developing a new "vacuum tube" configuration,
for
the sake of their higher (but not total) EMP resistance, around 15
years ago. They were ganged in groups, with the "tubes" being
cavities
cut in blocks of some kind of ceramic.

In the early 90's I dreamed up an alien sci-fi technology that had
never invented transistors, instead they made repairable integrated
tube circuits for their spacecraft by soldering the elements onto a
printed substrate in a large chamber ventilated to space.

Wild idea. Tightly vented, so as to avoid space dust?


When the
gain decreased they repainted all the cathodes with Caesium or Radium
in an Argon glove box.

?


I mentioned the idea to an engineer at work (Mitre) who told me about
ongoing research in that direction.
http://science.dodlive.mil/2013/12/0...ps-meet-tubes/

Wilder still to find out it was happening, and at super high freqs,
wot? Cool.

--
The beauty of the 2nd Amendment is that it will not be needed
until they try to take it. --Thomas Jefferson

On Thu, 20 Aug 2015 06:44:40 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Wed, 19 Aug 2015 20:12:40 -0400, wrote:
second son has built himself what ammounts to a "jumbotron" of 22"
monitors, simply by replacing caps in the power supply of out of
warranty units. He designed a replacement set of caps then bought in
bulk quantity.

Cool. Got a list of those caps?

http://www.badcaps.net/

Thanks.

--
The beauty of the 2nd Amendment is that it will not be needed
until they try to take it. --Thomas Jefferson

On 8/18/2015 6:49 AM, Lloyd E. Sponenburgh wrote:
Tom Gardner fired this volley in news:mqufgp$qs1$2
@speranza.aioe.org:

Can one use two discrete caps?


Indeed. "Dual caps" are just a packaging convenience. They're
fundamentally a service problem, because if half fails, you must replace
both.

Most discrete-component television sets of the late 60s and early 70s that
ended up on a service bench could be seen to have had at least one dual cap
replaced with single-capacitor equivalents.

Lloyd



With the dual caps, if one blows it rips the connection loose for the
other thus your pump stops if the fan cap blows. How can you duplicate
that protection?

On 8/18/2015 9:18 AM, Michael A. Terrell wrote:

I bought the 6GH8A by the case of 100 at a time, in the '70s.



For the time machine?

Tom Gardner fired this volley in news:mr7c7b$ob4$1
@speranza.aioe.org:

With the dual caps, if one blows it rips the connection loose for the
other thus your pump stops if the fan cap blows. How can you duplicate
that protection?


Tom, they most often fail by another mechanism. Most often, they just
lose capacity until they no longer will start their associated motor.

That "protection" is accidental, anyway. "Blowing" is less often seen
than just "venting", and they don't tear themselves apart mechanically
when they vent.

Adding protection for a bad compressor start would be easy enough... when
they don't start, they kick their over-temp switch, and that signal could
be used to turn off a latching relay on the fan circuit.

Adding protection in the opposite case would be harder, since most fan
motors are just split-phase induction motors, and if they have any
thermal protection at all, it's internal. You'd have to add some sort of
'air motion sensing' to manage that one.

Lloyd

Yes we know two with one blow. However both are by the same guy that
made them with faulty paper or seals. So both are in the trash.

It is for design and space. Often in designs you will see duals and
triples making pi or L filters and power supply brute force filters.
Martin

On 8/21/2015 9:22 AM, Tom Gardner wrote:
On 8/18/2015 6:49 AM, Lloyd E. Sponenburgh wrote:
Tom Gardner fired this volley in news:mqufgp$qs1$2
@speranza.aioe.org:

Can one use two discrete caps?


Indeed. "Dual caps" are just a packaging convenience. They're
fundamentally a service problem, because if half fails, you must replace
both.

Most discrete-component television sets of the late 60s and early 70s
that
ended up on a service bench could be seen to have had at least one
dual cap
replaced with single-capacitor equivalents.

Lloyd



With the dual caps, if one blows it rips the connection loose for the
other thus your pump stops if the fan cap blows. How can you duplicate
that protection?

Actually the start cap if dry won't start the motor well. The cap
is in series with the start winding and a switch. There is enough
working to start a slow ramp up to speed and once there have power.

The start cap is a reactive negative resistance to the coil's positive
resistance. (reactance really). A tug on a rope start and it will
turn over faster and catch.

Some caps have fuses in then - to protect the motor if the cap shorts.
Martin

On 8/21/2015 9:43 AM, Lloyd E. Sponenburgh wrote:
Tom Gardner fired this volley in news:mr7c7b$ob4$1
@speranza.aioe.org:

With the dual caps, if one blows it rips the connection loose for the
other thus your pump stops if the fan cap blows. How can you duplicate
that protection?


Tom, they most often fail by another mechanism. Most often, they just
lose capacity until they no longer will start their associated motor.

That "protection" is accidental, anyway. "Blowing" is less often seen
than just "venting", and they don't tear themselves apart mechanically
when they vent.

Adding protection for a bad compressor start would be easy enough... when
they don't start, they kick their over-temp switch, and that signal could
be used to turn off a latching relay on the fan circuit.

Adding protection in the opposite case would be harder, since most fan
motors are just split-phase induction motors, and if they have any
thermal protection at all, it's internal. You'd have to add some sort of
'air motion sensing' to manage that one.

Lloyd