What is the most powerful vacuum tube ever made?

[olds...@tubes.com]

What is the most powerful vacuum tube ever made?

I'm looking into building the most pewerful tube audio amplifier
possible. I'll be using 4 tubes in push-pull parallel. (per channel). My
goal is at least 5000 watts RMS per channel (if possible). I will likely
rewind some pole pigs (power pole transformers) for output transformers,
and possibly use one of them in reverse for the power supply
transformer, which should supply 3250 to 7500 volts to the plates (or up
to 15KV if I use a different pole pig rated for higher primary voltage).

[Mike Coon]

In article <kjr7mdte459o2ll2f...@4ax.com>,
olds...@tubes.com says...

Water-cooled loudspeakers?

Mike.

[upsid...@downunder.com]

On Fri, 03 Aug 2018 01:07:29 -0500, olds...@tubes.com wrote:

>What is the most powerful vacuum tube ever made?

I have seen at least 250-350 kW transmitter and AM modulator tubes,
some of which are water or vapor cooled.

>I'm looking into building the most pewerful tube audio amplifier
>possible. I'll be using 4 tubes in push-pull parallel. (per channel). My
>goal is at least 5000 watts RMS per channel (if possible). I will likely
>rewind some pole pigs (power pole transformers) for output transformers,

What is the frequency response of a pole pig transformer ?

>and possibly use one of them in reverse for the power supply
>transformer, which should supply 3250 to 7500 volts to the plates (or up
>to 15KV if I use a different pole pig rated for higher primary voltage).

Get a 3 phase connection, it greatly simplifies the power supply
filtering requirement.

[69883925...@nospam.org]

olds...@tubes.com wrote

>What is the most powerful vacuum tube ever made?
>
>I'm looking into building the most pewerful tube audio amplifier
>possible. I'll be using 4 tubes in push-pull parallel.

Any idea yet what you wil say through that PA?
And who the victims will be?

[Tauno Voipio]

This is not the largest, but enough to blow up your
pole pig transformers:

<https://www.cpii.com/docs/datasheets/75/4CV100-000E.pdf>

IIRC, the largest Eimac tube I've seen is a megawatt
tube, but it is made on special agreement only.

--

-TV

[Rob]

Not a good idea to use tubes for that. What you want to have is available
off-the-shelf both as PCB modules and 19" rack modules, it will be
much lighter, much cheaper, much safer and it will work much better!

e.g.: http://www.fullfataudio.com/products/ffa-10000/

And when you would use tubes, you would not make the most powerful
tube audio amplifier with a measly 5000 watts. Much more power was
produced in modulator amplifiers of classic AM transmitters with an
RF output of 100 times that. See the documentaries on WLW and info
on even stronger AM transmitters outside the USA.

[upsid...@downunder.com]

On Fri, 03 Aug 2018 01:07:29 -0500, olds...@tubes.com wrote:

>What is the most powerful vacuum tube ever made?
>
>I'm looking into building the most pewerful tube audio amplifier
>possible. I'll be using 4 tubes in push-pull parallel. (per channel). My
>goal is at least 5000 watts RMS per channel (if possible).

The real question is, do you have a single full range speakers with
5000 W power handling ?

If you are going to use speakers with separate (sub)woofers, why not
do the crossover at low levels and use separate amplifier to feed the
power hungry (sub)woofer. It would be natural to feed it with some
Class-D (PWM) amplifier.

If you want to drive the rest of the spectrums with tubes, please go
ahead (.e.g. to generate tube distortion by overdriving). Most likely
much less power is required. In addition much smaller output
transformer is required, if you can ignore the lowest 3-5 octaves.

[Ian]

On 2018-08-03, olds...@tubes.com <olds...@tubes.com> wrote:

> I'm looking into building the most pewerful tube audio amplifier
> possible.

Sounds like a bit of a Disaster Area in the making...


--
Ian

"Tamahome!!!" - "Miaka!!!"

[Rob]

It is a stupid idea to build the desired distortion into an expensive
and hard to replace part of the system. When you want to build a
high-power amplifier with the bad performance of a tube amplifier,
use a low-power tube amplifier as a preamp and drive a modern Class-D
amplifier with the resulting distorted signal, to have it cleanly
amplified to high power at high efficiency, low weight, etc.

Once you get tired of the "warm sound" you can always remove the tube
amplifier without having to start from scratch.

[Tauno Voipio]

A rule of thumb for the AM transmitter modulator is that
the audio power needs to be at least half of the DC input
power to the Class C power amplifier.

--

-TV

[Rob]

It is clear that with his 5000 watts he is about two orders of magnitude
short of the most powerful tube audio amplifier ever made, let alone the
most powerful tube audio amplifier possible. But maybe it would still
be the most pewerful, who knows?

[George Herold]

When I worked at the FEL (Free electron Laser) we had a SLAC Klystron that
was probably 100 MW.
http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-pub-10620.pdf
(Check out the unibrow in figure 9.)

George H.

[upsid...@downunder.com]

I was referring to electric guitar amplifiers, in which the distorting
amplifier and distorting speakers are part of the electric guitar
instrument.

In big (stadium size) events, a low power (100 W) tube amplifier and
also suitable low power speaker is used. A microphone is placed in
front of the speaker to get both the amplifier as well as speaker
distortion and then amplified by a linear chain to the final kW size
output :-).

With signals with high peak/average ratio, you can quite comfortably
overdrive a tube power amplifier without too much problems, while you
should never let a solid state amplifier chain clip. Thus the nominal
power output must be several times that of a tube amplifier in order
to get the same average audio SPL.

[Tauno Voipio]

> be the most powerful, who knows?

My guess is that the most powerful audio amplifiers have been
modulators for big AM transmitters. The biggest I have seen
is 200 kW modulator in the late Lahti AM station in southern
Finland. The transmitter was made by Brown Boveri & Cie (BBC).

At least Radio Moscow has run AM on 1 MW power level, maybe
also VOA in the years gone by. This would need an audio power
of around 700 kW, if the power amplifier is not run as a linear
amplifier, which is pretty wasteful at this power level, due
to the bad carrier-level efficiency of an AM linear.

--

-TV

[Lasse Langwadt Christensen]

https://www.cpii.com/docs/datasheets/78/8974.pdf

[upsid...@downunder.com]

Isn't that short peak power, not average power ?

[Phil Hobbs]

On 08/03/2018 06:09 AM, Ian wrote:
> On 2018-08-03, olds...@tubes.com <olds...@tubes.com> wrote:
>
>> I'm looking into building the most pewerful tube audio amplifier
>> possible.
>
> Sounds like a bit of a Disaster Area in the making...
>
>

And terrible songs!

Maybe the OP is planning to be dead for a year for tax reasons.....

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

[upsid...@downunder.com]

On Fri, 3 Aug 2018 16:20:43 +0300, Tauno Voipio

At least the 500 kW short wave AM/SSB Brown Bovery transmitters
commissioned in the 1980's in Pori, Finland, used audio controlled PWM
to generate the final RF tube anode voltage. So no need for a huge
power audio amplifier or huge modulation transformers.

I do not know what they use in the on site 600 kW AM medium wave
transmitter.

[Rob]

This is strange. Above I wrote pewerful because the original poster
also wrote that. Now my text is quoted and it reads powerful. How
can that be? Is there spelling correction in quoted text and why doesn't
it happen on line 8?

> My guess is that the most powerful audio amplifiers have been
> modulators for big AM transmitters. The biggest I have seen
> is 200 kW modulator in the late Lahti AM station in southern
> Finland. The transmitter was made by Brown Boveri & Cie (BBC).

It is my guess too.

> At least Radio Moscow has run AM on 1 MW power level, maybe
> also VOA in the years gone by. This would need an audio power
> of around 700 kW, if the power amplifier is not run as a linear
> amplifier, which is pretty wasteful at this power level, due
> to the bad carrier-level efficiency of an AM linear.

Hence my claim of being about two orders of magnitude short.
Of course, current AM transmitters no longer work this way.

[John Larkin]

On Fri, 03 Aug 2018 01:07:29 -0500, olds...@tubes.com wrote:

>What is the most powerful vacuum tube ever made?
>

Probably an ignitron, possibly a krytron, but the THD specs are
mediocre.

Why?

The transformers are the problem.



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

[Rob]

That is like what I wrote. Nobody would want to carry a 5000 watt
tube audio amplifier to an event when they can have the same thing
as a 2U rack module weighing 14kg.

> With signals with high peak/average ratio, you can quite comfortably
> overdrive a tube power amplifier without too much problems, while you
> should never let a solid state amplifier chain clip. Thus the nominal
> power output must be several times that of a tube amplifier in order
> to get the same average audio SPL.

Such an amplifier likely contains (or requires an external) sound
processor that cleverly limits the amplitude without hard clipping.

[bitrex]

For the cost of building the most powerful tube amp ever you could buy a
pretty nice used sports car. Or less expense. Less dangerous. Girls will
like you better.

[bitrex]

Sounds like one of those "if you have to ask how you probably
shouldn't"-kind of projects.

It'll probably be cheaper in parts and labor cost to just buy one off
the shelf, anyway. I mean off the floor. Reinforced concrete floor.

<https://www.surplussales.com/Microphones-Audio/MicroAudio-7.html>

[Rob]

bitrex <us...@example.net> wrote:
> It'll probably be cheaper in parts and labor cost to just buy one off
> the shelf, anyway. I mean off the floor. Reinforced concrete floor.

:-)
Not only in parts and labor cost but also in human lives...

[bitrex]

On 08/03/2018 09:31 AM, Phil Hobbs wrote:
> On 08/03/2018 06:09 AM, Ian wrote:
>> On 2018-08-03, olds...@tubes.com <olds...@tubes.com> wrote:
>>
>>> I'm looking into building the most pewerful tube audio amplifier
>>> possible.
>>
>> Sounds like a bit of a Disaster Area in the making...
>>
>>
> And terrible songs!
>
> Maybe the OP is planning to be dead for a year for tax reasons.....
>
> Cheers
>
> Phil Hobbs
>

Thinking about the output device specifics is bikeshedding at this point
in the design anyway. If one were serious one would be starting at the
PSU and working forwards. Oh, it's gonna be a complex and glorious PSU
for sure, with a pretty sophisticated fail-safing system,
overvoltage/overcurrent protection, and probably uP-controlled startup
sequencing and bias monitoring.

Or u can just build a house-burning down murder machine I guess.

[John Larkin]

Some old AM or shortwave transmitters ran plate modulated above a
megawatt.

[bitrex]

Starting at the output devices is bikeshedding, anyone who was
serious/non-crazy would be thinking (sleepless nights in horror) at what
the cost in design time and parts to make a safe reliable PSU for such
an amplifier would be to start.

[bitrex]

Ya I think they still use them in Mexico and the Carribean to broadcast
end-times ranting from that kooky old kid-toucher pastor out of SC.

[George Herold]

Right. pulsed power.

GH

[upsid...@downunder.com]

Agreed that the PSU is an issue, if you have only a 50/60 Hz single
phase feed, especially due to the lack of high voltage electrolytic
capacitors.

However, if you have a three phase feed (230/400 V in Europe or
277/480 V in the US) the power supply is trivial. Just put a 6 pulse
rectifier after the anode voltage transformer. If you have two
secondaries, put one in wye and the other in delta and you can use 12
pulse rectifier, generating smoother DC and reduce the power factor on
the primary side.

Tubes can take a lot of punishment, so a 30-60 s time delay should be
enough, before switching on the anode voltage, when the cathode has
reached full operational temperature.

[Tauno Voipio]

Pori has been down since over a decade ago, see:
<https://yle.fi/uutiset/osasto/news/yle_ends_short_wave_broadcasts/5756519>.

--

-TV

[Tauno Voipio]

To stay in the style: A sturdy transformer, some mercury-arc rectifiers,
a hefty swinging choke and a bunch of oil capacitors.

--

-TV

[Johnny B Good]

On Fri, 03 Aug 2018 07:34:12 +0100, Mike Coon wrote:

> In article <kjr7mdte459o2ll2f...@4ax.com>,
> olds...@tubes.com says...

>>
>> What is the most powerful vacuum tube ever made?
>>
>> I'm looking into building the most pewerful tube audio amplifier
>> possible. I'll be using 4 tubes in push-pull parallel. (per channel).
>> My goal is at least 5000 watts RMS per channel (if possible). I will
>> likely rewind some pole pigs (power pole transformers) for output
>> transformers,
>> and possibly use one of them in reverse for the power supply
>> transformer, which should supply 3250 to 7500 volts to the plates (or
>> up to 15KV if I use a different pole pig rated for higher primary
>> voltage).
>

> Water-cooled loudspeakers?
>
Good question. :-)

The OP's an hammerchewer with his talk of using BFO transformers. I'm
not surprised I didn't see the OP since I'm guessing I must have
killfiled him some time back.

If his plan is to annoy the neighbours, he could scale his BFO Amp
requirements back by a good 16 to 20dB using horn loaded pressure
transducers just like the old cinema houses used to do when filling a
large auditorium with high level sound using just a 5W rms valve
amplifier. If he's ok with a cardioid sound field, he could gain an extra
3dB by loading the pressure transducer diaphragm(s) front and back with a
matching pair of horns each.

There's no point in wasting energy and money on superfluous matching
transformers when you can use paralleled valves (vacuum tubes) in a DC
coupled push-pull bridged output configuration fed from a voltage doubled
240v rms supply with +/-300 volt HT rails. That's a configuration that
should drive a 16 ohm speaker load to 5KW rms with some margin to
spare. :-)

Of course, he could save himself the bother of floating heater supplies
and the sheer quantity of 807 valves or whatever readily available valves
he can get his hands on if a 10KW am Tx high level modulator amplifier
doesn't float his boat by building a solid state equivalent of the DC
coupled valve design using high voltage high slew rate power fets instead.

As I said above, the OP's an 'ammerchewer.

--
Johnny B Good

[whit3rd]

On Thursday, August 2, 2018 at 11:11:15 PM UTC-7, olds...@tubes.com wrote:
> What is the most powerful vacuum tube ever made?

Varian made 23MW (klystrons, I think) for SLAC, and that
two-mile accelerator is still in service, so they're probably
rebuilding 'em from time to time.

[whit3rd]

On Thursday, August 2, 2018 at 11:11:15 PM UTC-7, olds...@tubes.com wrote:
> What is the most powerful vacuum tube ever made?

Don't know how many of 'em exist, but reportedly these
folk got higher power than you'll need,

<https://www.slac.stanford.edu/pubs/slacpubs/7000/slac-pub-7232.pdf>

but the 535 kV power (and 700A electron gun) will not be compatible with
most power utilities' offerings.

[bitrex]

Yeah, 1920s-style. I'm sure there's someone out there who daily-drives a
Model T, too. Bob Pease daily drove a 60's Beetle.

[bitrex]

On 08/03/2018 12:56 PM, Tauno Voipio wrote:

You could look at the Westinghouse FG-10 design as a ballpark
for the size power supply you'd need for two channels at 10kW total.
"sturdy transformer"? There are _several_ very sturdy-looking iron
transformers in it at the bottom of the cabinet, each one looks to be
about the size of a microwave oven.

You're not running this hypothetical amp off a 120V wall socket, sorry
to say.

[bitrex]

You're certainly going to need some kind of fast-acting overcurrent/bias
voltage loss detecting system; self-bias is probably a non-starter and
at those power levels loss of a bias supply will probably be a genuine
disaster that'll make the local news at least ;-)

[upsid...@downunder.com]

On Fri, 3 Aug 2018 19:50:08 +0300, Tauno Voipio

After that it was leased to China Radio International (ex. Radio
Peking). At least the medium wave transmitter at 963 kHz has been used
quite recently.

[upsid...@downunder.com]

Power the anode supply contactor (relay) from the bias supply. If the
bias is lost, the contactor will release. Since in a 3 phase supply,
typically there are no big capacitor on the DC side, the anode voltage
will drop quite rapidly. As noted previously, tubes can handle some
punishment.

[upsid...@downunder.com]

How about an aviation motor generator with 50/60 Hz (single phase)
input and 400 Hz output. It greatly reduces the transformer size (as
well as filter capacitor size, in case the 400 Hz is single phase)..

[tabb...@gmail.com]

the efficiency of those things is crappy, you'd lose nearly half the power in it.


NT

[Jeff Liebermann]

On Fri, 03 Aug 2018 01:07:29 -0500, olds...@tubes.com wrote:

>What is the most powerful vacuum tube ever made?

Dunno. If you're talking about microwave, it's a Gyrotron:
<https://en.wikipedia.org/wiki/Gyrotron.
Typical max output is 1 megawatt per tube.
<https://www.google.com/search?q=gyrotron&tbm=isch>

>I'm looking into building the most pewerful tube audio amplifier

>possible. I'll be using 4 tubes in push-pull parallel. (per channel). My
>goal is at least 5000 watts RMS per channel (if possible). I will likely
>rewind some pole pigs (power pole transformers) for output transformers,
>and possibly use one of them in reverse for the power supply
>transformer, which should supply 3250 to 7500 volts to the plates (or up
>to 15KV if I use a different pole pig rated for higher primary voltage).

You're probably ok at 3250 to 7500 volts, but 15kV will probably turn
your audio amplifier into an x-ray generator. Have your lead shielded
underwear handy.

If you really want high power audio, what you want is a pneumatic
modulator, amplifier, and directional horn:
<https://en.wikipedia.org/wiki/Compressed_air_gramophone>
<https://www.google.com/search?q=auxetophone&tbm=isch>
Please note that sound are nothing more than controlled changes in air
pressure. You don't need a loudspeaker:
<http://wynalazki.andrej.edu.pl/images/duze2/glosnik1.jpg>
to do that. Just something that will move lots of air quickly, such
as a big air compressor. For example, if you happen to have a 150
horsepower air compressor, and high power fluidics (air is a
compressible fluid) modulator and amplifier handy, you can build
rather high power sound system:
<https://www.psaudio.com/article/the-mother-of-all-speakers-moas/>
<http://www.noiseaddicts.com/2008/09/loudest-speaker-in-the-world/>
150 hp * 745 watts/hp = 112,000 watts maximum audio power
Actually, it's only about half that, since it takes almost as much
power to run the modulator as it does to product the output pressure
changes.

I worked for a company that built something like that in the 1960's
while I was in early college. It was suppose to be used for
projecting propaganda recordings at the enemy across the WWII style
battlefield. I helped build the calibration lab, so I didn't get to
see the monster in action very often.




--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Lasse Langwadt Christensen]

lørdag den 4. august 2018 kl. 03.54.17 UTC+2 skrev Jeff Liebermann:
> On Fri, 03 Aug 2018 01:07:29 -0500, olds...@tubes.com wrote:
>
> >What is the most powerful vacuum tube ever made?
>
> Dunno. If you're talking about microwave, it's a Gyrotron:
> <https://en.wikipedia.org/wiki/Gyrotron.
> Typical max output is 1 megawatt per tube.
> <https://www.google.com/search?q=gyrotron&tbm=isch>
>

https://www.cpii.com/docs/datasheets/78/8974.pdf

"The maximum anode dissipation rating is 1500 kW steady state"

[Arid ace]

On Fri, 03 Aug 2018 01:07:29 -0500, olds...@tubes.com wrote:

>What is the most powerful vacuum tube ever made?
>

>I'm looking into building the most pewerful tube audio amplifier
>possible. I'll be using 4 tubes in push-pull parallel. (per channel). My
>goal is at least 5000 watts RMS per channel (if possible). I will likely
>rewind some pole pigs (power pole transformers) for output transformers,
>and possibly use one of them in reverse for the power supply
>transformer, which should supply 3250 to 7500 volts to the plates (or up
>to 15KV if I use a different pole pig rated for higher primary voltage).
>

Perhaps not the most powerful tube, the RCA 5831 triode has a lot to offer. With
a filament requirement of 6V at 2,220A it can be useful to heat the house as
well. With 10 KV on the plates in a push-pull configuration it can deliver about
370 KW which might be sufficient to impress all audiophiles within a radius of
~10 miles, when fitted with appropriate speakers. Complete details about this
tube: https://frank.pocnet.net/sheets/049/5/5831.pdf

[Steve Wilson]

On Friday, August 3, 2018 at 10:34:50 PM UTC-4, Arid ace wrote:
> Perhaps not the most powerful tube, the RCA 5831 triode has a lot to offer. With
> a filament requirement of 6V at 2,220A it can be useful to heat the house as
> well. With 10 KV on the plates in a push-pull configuration it can deliver about
> 370 KW which might be sufficient to impress all audiophiles within a radius of
> ~10 miles, when fitted with appropriate speakers. Complete details about this
> tube: https://frank.pocnet.net/sheets/049/5/5831.pdf

Here's a 2,158 KW power tetrode
http://www.cpii.com/docs/datasheets/78/8974.pdf

A 7.5MW pulse amplifier

https://www.sokoll-technologies.de/Museum/Auto/Dokumente/Datenblatt_7835-V1_Burle.pdf Datenblatt_7835-V1_Burle.pdf

This should excite the hams. The 1963 RCA Power Tube Catalog

https://www.kevinchant.com/uploads/7/1/0/8/7108231/1963_rca_power_tubes_guide.pdf

[bitrex]

Don't forget to protect yer output driver amp tubes too! They'll likely
need a different lower voltage bias supply but for an amp of this size
just the driver for the huge final tubes (power triodes, probably?) is
gonna be like the equivalent of a Marshall stack amp power stage, maybe
bigger.

And maybe even the drivers for the drivers.

[upsid...@downunder.com]

On Fri, 03 Aug 2018 18:54:10 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:

>
>>I'm looking into building the most pewerful tube audio amplifier
>>possible. I'll be using 4 tubes in push-pull parallel. (per channel). My
>>goal is at least 5000 watts RMS per channel (if possible). I will likely
>>rewind some pole pigs (power pole transformers) for output transformers,
>>and possibly use one of them in reverse for the power supply
>>transformer, which should supply 3250 to 7500 volts to the plates (or up
>>to 15KV if I use a different pole pig rated for higher primary voltage).
>
>You're probably ok at 3250 to 7500 volts, but 15kV will probably turn
>your audio amplifier into an x-ray generator. Have your lead shielded
>underwear handy.

Not an issue with full wave rectified 15 kVac.

Below 25kVdc, the X-ray spectrum is just the continuum, above 25 kV
nasty discrete X-ray lines will also appear. For this reason the power
supply for old shadow mask CRTs also contained a shunt regulator (like
the PD500 power triode) to limit the CRT anode voltage to 25 kV.

[jurb...@gmail.com]

They got you beat -

https://www.audioasylum.com/cgi/vt.mpl?f=general&m=738587

Well it's only 2,000 watts per channel more than you wanted, why not ?

I like how it says it was designed for research into high intensity sound.

No shit ? Really ? Could it be ? You think ?

[bitrex]

Here's a homebrew reference design for a 1000 watt monoblock, look at
that xfmr just look at the mufucka. It probably cost about a grand.

<http://www.chambonino.com/construct/const9.html>

OP is talking about building an amp five times that. I can think of
better ways to throw money away like buying a boat maybe

[Jeff Liebermann]

Thanks. I couldn't recall at what voltage the problems start and was
too lazy to check. Looks like 20kV is where a vacuum tube starts to
produce x-rays. Interesting video shows how it works:
"Creating X-rays with a standard vacuum tube"
<https://www.youtube.com/watch?v=yLSu_UjrcUA>

I've tried this experiment with various vacuum tubes. My voltage
source was smaller and only went to 25kV (powder coating paint gun):
<https://www.eastwood.com/eastwood-dual-voltage-powder-gun-starter-kit.html>
so I didn't see the continuous x-rays as in the video at 30kV.

[69883925...@nospam.org]

upsidedown wrote

>Below 25kVdc, the X-ray spectrum is just the continuum, above 25 kV
>nasty discrete X-ray lines will also appear. For this reason the power
>supply for old shadow mask CRTs also contained a shunt regulator (like
>the PD500 power triode) to limit the CRT anode voltage to 25 kV.

The PD500 was a real Xray source though.
A college of mine was repairing a monitor with it and the metal HV cage open.
His face got burned by the radiation.
The glass of those tubes would turn into a special bluish color over time .
There are you tube movies of someone using those tubes to take X-ray pictures of stuff.

[Rob]

The guy is apparently not concerned about efficiency.
To get 5000 watts RMS out using tubes of course he will require some 20kW
of input, a couple more or less would not matter.

Would he use a modern Class-D amplifier he would have a mains to output
effciency typically over 80%.

[Tauno Voipio]

You're just moving the iron and copper bulk from the
transformer and filter to the frequency converter, and
taking in addition the maintenance problems of the
rotating machinery.

400 Hz hum is more annoying than the customary 50/60 Hz
hum, so you'll need better filtering there. Been there,
done that, in 35 years in avionics engineering.

--

-TV

[Piotr Wyderski]

Tauno Voipio wrote:

> IIRC, the largest Eimac tube I've seen is a megawatt
> tube, but it is made on special agreement only.

The MW-range tubes were quite popular in the AM broadcasting
industry. Tailor-made -- yes, rare -- no, not really. A good
question, if we count only the continuous-power tubes, the
radar-style gigawatt ratings are cheating.

Best regards, Piotr

[Piotr Wyderski]

Tauno Voipio wrote:

> At least Radio Moscow has run AM on 1 MW power level

Polish Radio Channel 1 (then at 227kHz) used to run on 2MW,
feeding the talles antenna mast in world (a full-blown
half-wave, 646m). EIRP=3MW.

https://en.wikipedia.org/wiki/Warsaw_radio_mast

Sometimes it caused dieelectric breakdown and the arc
current was audio-modulated. This way you could hear our
supreme leader speaking from the sky. :->

Then several morons were hired to do some maintenance, with the
following result:

http://www.smartage.pl/wp-content/uploads/2017/11/2-22-3...@2x.jpg

Best regards, Piotr

[Piotr Wyderski]

whit3rd wrote:

> but the 535 kV power (and 700A electron gun) will not be compatible with
> most power utilities' offerings.

I'm pretty sure I've seen a wall socket compatible with these somewhere:

https://prd-wret.s3-us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/dreamstime_l_4671381%20%281%29.jpg?itok=mpAbleQ0

Best regards, Piotr

[Piotr Wyderski]

Ian wrote:

>> I'm looking into building the most pewerful tube audio amplifier
>> possible.
>

> Sounds like a bit of a Disaster Area in the making...

Not at all, I think he and his friends are working happily on that and
the progress is just fine:

https://www.youtube.com/watch?v=vul4SYL4QiQ

Best regards, Piotr

[Boris Mohar]

On Fri, 03 Aug 2018 01:07:29 -0500, olds...@tubes.com wrote:

Large Hadron Collider

Snip suicide plan.....



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

void _-void-_ in the obvious place



---
This email has been checked for viruses by Avast antivirus software.
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[tabb...@gmail.com]

On Saturday, 4 August 2018 08:26:06 UTC+1, Rob wrote:

> tabb...@gmail.com <tabbypurr wrote:
> > On Friday, 3 August 2018 22:36:32 UTC+1, upsid...@downunder.com wrote:
> >> On Fri, 3 Aug 2018 19:56:48 +0300, Tauno Voipio
> >> <tauno....@notused.fi.invalid> wrote:
> >> >On 3.8.18 18:49, bitrex wrote:
> >> >> On 08/03/2018 11:45 AM, Rob wrote:
> >> >>> bitrex <us...@example.net> wrote:
> >
> >> >>>> It'll probably be cheaper in parts and labor cost to just buy one off
> >> >>>> the shelf, anyway. I mean off the floor. Reinforced concrete floor.
> >> >>>
> >> >>> :-)
> >> >>> Not only in parts and labor cost but also in human lives...
> >> >>>
> >> >>
> >> >> Starting at the output devices is bikeshedding, anyone who was
> >> >> serious/non-crazy would be thinking (sleepless nights in horror) at what
> >> >> the cost in design time and parts to make a safe reliable PSU for such
> >> >> an amplifier would be to start.
> >> >
> >> >To stay in the style: A sturdy transformer, some mercury-arc rectifiers,
> >> >a hefty swinging choke and a bunch of oil capacitors.
> >>
> >> How about an aviation motor generator with 50/60 Hz (single phase)
> >> input and 400 Hz output. It greatly reduces the transformer size (as
> >> well as filter capacitor size, in case the 400 Hz is single phase)..
> >
> > the efficiency of those things is crappy, you'd lose nearly half the power in it.
>
> The guy is apparently not concerned about efficiency.

If that's true then someone isn't thinking it through. He has a limited mains supply but wants as much P_out as possible.

> To get 5000 watts RMS out using tubes of course he will require some 20kW
> of input, a couple more or less would not matter.
>
> Would he use a modern Class-D amplifier he would have a mains to output
> effciency typically over 80%.

Sure, but he specifically wants valves & analogue.


NT

[Tauno Voipio]

It was the exchange of the guy ropes going awry.

--

-TV

[Piotr Wyderski]

Tauno Voipio wrote:

> It was the exchange of the guy ropes going awry.

The manager of the maintenance team was sentenced to 2.5y in prison.

Best regards, Piotr

[Neon John]

On Fri, 03 Aug 2018 18:54:10 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:

>If you really want high power audio, what you want is a pneumatic
>modulator, amplifier, and directional horn:
><https://en.wikipedia.org/wiki/Compressed_air_gramophone>
><https://www.google.com/search?q=auxetophone&tbm=isch>
>Please note that sound are nothing more than controlled changes in air
>pressure. You don't need a loudspeaker:
><http://wynalazki.andrej.edu.pl/images/duze2/glosnik1.jpg>
>to do that. Just something that will move lots of air quickly, such
>as a big air compressor. For example, if you happen to have a 150
>horsepower air compressor, and high power fluidics (air is a
>compressible fluid) modulator and amplifier handy, you can build
>rather high power sound system:
><https://www.psaudio.com/article/the-mother-of-all-speakers-moas/>
><http://www.noiseaddicts.com/2008/09/loudest-speaker-in-the-world/>
> 150 hp * 745 watts/hp = 112,000 watts maximum audio power
>Actually, it's only about half that, since it takes almost as much
>power to run the modulator as it does to product the output pressure
>changes.

There is a much larger speaker at the Redstone Arsenal in Huntsville.
It's about 60 ft tall and an approx 30 ft square at the bottom. It is
a folded exponential horn.

It was designed to make the same level of sound that the scientists
estimated the Saturn 5 would make. It is aimed off the reservation so
they could assess any damage that SPL would cause.

My cousin was the Chief Metallurgist for the Army at the Arsenal. He
got me pretty free access to the base. When I was about 15, he took
me over to see and explore the horn. I climbed all over it but I
don't remember many details. I do recall seeing several large diesel
engines on the site so the audio drive probably was pneumatic like the
MOAS.

About 15 years ago, not long before he was to die from Chron's
disease, he took us on another tour of the Arsenal. The speaker was
still there and bore a brass plaque stating that it was a National
Historic Site.

Unfortunately, Google came up with nothing. Strange.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

[Jeff Liebermann]

On Sat, 04 Aug 2018 11:39:20 -0400, Neon John <n...@never.com> wrote:

>There is a much larger speaker at the Redstone Arsenal in Huntsville.
>It's about 60 ft tall and an approx 30 ft square at the bottom. It is
>a folded exponential horn.
>
>It was designed to make the same level of sound that the scientists
>estimated the Saturn 5 would make. It is aimed off the reservation so
>they could assess any damage that SPL would cause.

I found a rather vague reference to such a horn under a history of the
Saturn test (F1 engine). See Pg 94:
<https://the-eye.eu/public/concen.org/The%20Saturn%20Myth%20Occult%20Symbolism%20Saturn%20Worship/Stages%20to%20Saturn.pdf>
(30.8MB)
Reverberations of the Saturn tests were quickly felt. The
acoustical impact was quite evident in the immediate area
around the city of Huntsville, and the long-range sound
propagation occurred at distances up to 160 kilometers.
The result was a rash of accidental damage to windows and
wall plaster, followed by a rash of damage claims (some-
times filed by citizens on days when no tests had been
conducted). Aware that climatic conditions caused very
pronounced differences in noise levels and long-range
sound propagation, engineers began taking meteorological
soundings and installed a huge acoustical horn atop a tower
in the vicinity of the test area. No ordinary tooter, the
horn was over 7.6 meters long and had a huge flared aperture
over 4.6 meters high. Its sonorous gawps, bounced off a
network of sound recorders, gave acoustical engineers a
good idea whether it was safe to fire the big rockets on
overcast days.

There are some low quality photographs in the 500 page book, but none
showing a big horn. However, I did find this photo:
<https://www.al.com/living/index.ssf/2016/12/weird_vintage_alabama_photos_t.html>
which seems to fit the aforementioned dimensions and description:
<https://www.al.com/living/index.ssf/2016/12/weird_vintage_alabama_photos_t.html>
<https://image.al.com/home/bama-media/width620/img/living_impact/photo/hayes-horn-1966jpg-490339bdc40cf807.jpg>
I would have expected it to be much longer.

In another document, the sound level at the shopping center was
measured at 118dB. I'm surprised it didn't break windows and ear
drums. See Pg18:
<http://lcweb2.loc.gov/master/pnp/habshaer/al/al1100/al1196/data/al1196data.pdf>
(1.3MB)

>My cousin was the Chief Metallurgist for the Army at the Arsenal. He
>got me pretty free access to the base. When I was about 15, he took
>me over to see and explore the horn. I climbed all over it but I
>don't remember many details. I do recall seeing several large diesel
>engines on the site so the audio drive probably was pneumatic like the
>MOAS.

Yep. Big diesel powered air compressors were what drove such
speakers. I vaguely recall that some were powered by a diesel train
engine but might be mistaken. I suspect that the release of all that
pressure would probably have frozen any water in the air and turned it
into a snow blower. I don't recall any mention of that problem. Like
a musical horn, the low frequency limit is controlled by the length of
the horn, while the high frequency end is limited by the modulator.
The Huntsville horn was trying in mimic the F1 engine(s), which
according to the history, resonated at 5.25Hz. That requires are
really long and probably folded horn. The battlefield horn carries
voice grade audio, where the bottom limit was about 300Hz, and could
therefore be much shorter.

>About 15 years ago, not long before he was to die from Chron's
>disease, he took us on another tour of the Arsenal. The speaker was
>still there and bore a brass plaque stating that it was a National
>Historic Site.
>
>Unfortunately, Google came up with nothing. Strange.

I found the photo with an image search using:
<https://www.google.com/search?tbm=isch&q=redstone+arsenal+horn>
and the documents by manually groveling through:
<https://www.google.com/search?q=redstone+arsenal+%22horn%22+saturn+5>
Note the quotes around "horn" which makes it mandatory to have the
word "horn" in the initial search results.

>John
>John DeArmond
>http://www.neon-john.com
>http://www.tnduction.com
>Tellico Plains, Occupied TN
>See website for email address

[Jeff Liebermann]

On Sat, 04 Aug 2018 11:26:49 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:



> ... installed a huge acoustical horn atop a tower

> in the vicinity of the test area. No ordinary tooter, the
> horn was over 7.6 meters long and had a huge flared aperture
> over 4.6 meters high.

Here's the audiophile version of the Saturn 5 test horn:
<http://www.mh-audio.nl/Horn/GExpoHorn.asp>
Clever design methinks but I don't think I want it in my house.

Trying to see what the 4.6 meter diameter test horn would do, I
plugged these numbers into the calculator;
Low cutoff frequency = 5Hz
Throat diameter = 460 cm (4.6 meters)
Steps = 25
which resulted in a horn length = 1692.3 cm or 17 meters long. That's
much longer than the Saturn 5 test horn, which suggests that it wasn't
intended to mimic engine vibrations.

Interactively plugging numbers for the low end cutoff frequency, I
get:
low freq cutoff = 7.9 Hz
horn length = 756 cm
Close enough. So, the big horn was good for about 8Hz.

[Tim Williams]

Largest continuous duty, that's relevant to your application (i.e. not RF)
is the 8974, 1.5MW plate dissipation.

5kW is rather pedestrian for industrial applications; they're still being
maintained and sold, probably on the cheap side of things. Commercial
applications otherwise (like radiotransmitters) are basically all solid
state now, for good reason.

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

<olds...@tubes.com> wrote in message
news:kjr7mdte459o2ll2f...@4ax.com...

> What is the most powerful vacuum tube ever made?
>

> I'm looking into building the most pewerful tube audio amplifier

[Chris Jones]

I can't find it now, but I saw on youtube someone detecting significant
amounts of xrays from a vacuum tube at 5kV. I think the problem is that
most detectors are insensitive to low energy xray photons so people
think there is no emission, but depending on the glass envelope, there
might be, it is just hard to detect apart from by waiting for it to
disrupt your DNA. Below 5kV there are definitely xrays within the vacuum
tube, the question is whether or not they can get out. I would certainly
suggest being very careful at even 5kV, and don't trust you xray
detector to work for low energy xray photons, unless you have a good
reason to.

[69883925...@nospam.org]

Chris Jones wrote:
>I can't find it now, but I saw on youtube someone detecting significant
>amounts of xrays from a vacuum tube at 5kV. I think the problem is that
>most detectors are insensitive to low energy xray photons so people
>think there is no emission, but depending on the glass envelope, there
>might be, it is just hard to detect apart from by waiting for it to
>disrupt your DNA. Below 5kV there are definitely xrays within the vacuum
>tube, the question is whether or not they can get out. I would certainly
>suggest being very careful at even 5kV, and don't trust you xray
>detector to work for low energy xray photons, unless you have a good
>reason to.

Some geiger counters can also make good X-ray detectors:
https://en.wikipedia.org/wiki/Geiger_counter

I have a couple of those in use, of various types.

[upsid...@downunder.com]

The continuous X-ray spectrum looks very much like black-body
radiation. There is a distinct peak, which frequency direct
proportional to frequency (hence inversely proportional to wavelength)
to the electron energy (in keV), while in standard black-body
radiation the wavelength is inversely proportional to temperature.
When viewed on a log-log graph, in both cases the slope is steeper on
the shorter wavelength side and so on. Some physics text books even
suggests that it _is_ the same phenomenon.

At 5 keV, the total X-radiation is more than two orders of magnitude
below that of 25 keV, so not to worry about the radiation at 5 kV
anode voltage.

Up to about 25 kV, the spectrum looks just like black-body radiation.
At higher voltages, there are discrete spectral lines (depending on
target material), in addition to the black.body continuum.

[upsid...@downunder.com]

On Sat, 4 Aug 2018 23:29:23 -0500, "Tim Williams"
<tiw...@seventransistorlabs.com> wrote:

>Largest continuous duty, that's relevant to your application (i.e. not RF)
>is the 8974, 1.5MW plate dissipation.

RF tubes are OK as long as you can amplitude them. Just add an
envelope detector (diode detector) and drive the speaker. Make sure
you handle the detector DC bias issue.

[Tim Williams]

<upsid...@downunder.com> wrote in message
news:bnedmdh9l3c3tma8j...@4ax.com...

> RF tubes are OK as long as you can amplitude them. Just add an
> envelope detector (diode detector) and drive the speaker. Make sure
> you handle the detector DC bias issue.

Good point.

Follow-up question: is there a 100MW+ microwave diode out there? ;-)

[Chris Jones]

Two orders of magnitude is not necessarily a sufficient safety factor.
In a power amplifier I might well be running two orders of magnitude
more anode current than a dental xray tube (there goes the "safety
factor") and with no shielding that could do me a serious lot of damage
within hours or less. The only options I would consider safe are either
to calculate how much shielding would be needed and make sure it is
there in the glass and metalwork, or obtain a detector that is provably
sensitive to the wavelength of photons that could be present.

[Neon John]

On Sat, 04 Aug 2018 11:57:50 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:

>which resulted in a horn length = 1692.3 cm or 17 meters long. That's
>much longer than the Saturn 5 test horn, which suggests that it wasn't
>intended to mimic engine vibrations.
>
>Interactively plugging numbers for the low end cutoff frequency, I
>get:
> low freq cutoff = 7.9 Hz
> horn length = 756 cm
>Close enough. So, the big horn was good for about 8Hz.

The photo you presented is not the Redstone horn. The Redstone horn
is rectangular and use folding techniques similar to the Klipsh Horn.

That's the danger of being a URL and Wicki warrior. You don't know
anything about what you're trying to disprove so you accept the first
thing that looks close. A true obsession.

[Cursitor Doom]

On Sat, 04 Aug 2018 23:29:23 -0500, Tim Williams wrote:

> 5kW is rather pedestrian for industrial applications; they're still
> being maintained and sold, probably on the cheap side of things.
> Commercial applications otherwise (like radiotransmitters) are basically
> all solid state now, for good reason.

My newsreader truncated the last bit of the title of this thread; it
appeared to read, "What is the most powerful vacuum cleaner ever made?"
I was about to remind the OP to use an 'OT' prefix.




--
This message may be freely reproduced without limit or charge only via
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protocols constitutes acceptance of this condition.

[upsid...@downunder.com]

On Sun, 5 Aug 2018 23:31:38 +1000, Chris Jones

The shortest X-ray wavelength possible from 1200 V is 1 nm. The peak
wavelength is slightly longer, definitely only soft X-ray.

At 25 kV, the minimum wavelength is 50 pm in the hard X-rays.

I did not find a direct evidence that the X-ray bremsstrahlung (BS)
continuum behaves like black-body (BB) continuum, but at least in the
BB case, the total energy is proportional to the forth power. If this
applies also to BS, the total BS at 25 kV would be 160000 times
stronger than at 1200 V.

So a 1-2 kV actual anode voltage (not power supply unloaded voltage)
would not be an issue, unless you stick your nose constantly among the
tubes, not recommended :-).

Getting an electric shock in your nose is quite unpleasant and may
affect concentration for a day. Done that, not recommended :-).

[Mike Coon]

In article <mQw9D.1980280$nr7.1...@fx31.am4>, lugnut808
@spam.yahoo.com says...

>
> I can't find it now, but I saw on youtube someone detecting
significant
> amounts of xrays from a vacuum tube at 5kV. I think the problem is that
> most detectors are insensitive to low energy xray photons so people
> think there is no emission, but depending on the glass envelope, there
> might be, it is just hard to detect apart from by waiting for it to
> disrupt your DNA. Below 5kV there are definitely xrays within the vacuum
> tube, the question is whether or not they can get out. I would certainly
> suggest being very careful at even 5kV, and don't trust you xray
> detector to work for low energy xray photons, unless you have a good
> reason to.

It should be easy to detect ionising radiation with an electroscope, and
it is easy to build a cheap one of those.I remember doing it myself as a
student, but I did have access to fine metal film, though not actually
gold leaf.

Mike.

[69883925...@nospam.org]

Mike Coon wrote:
>It should be easy to detect ionising radiation with an electroscope, and
>it is easy to build a cheap one of those.I remember doing it myself as a
>student, but I did have access to fine metal film, though not actually
>gold leaf.
>
>Mike.

I have a few pen type radiation detectors like that,
you charge the (electrometer) by pluggin it in into a unit,
then put the pen in your pocket.
At the end of the day you read the electroscope through a small window with a scale
in the pen to see how much radiation you have been exposed too.
Payed 10 Euro for the set.. Army surplus.
Really nice stuff.
http://217.120.43.67/nuclear/radiation_pen_IMG_6534.JPG

And that is a raspberry webserver.

[Mike Perkins]

Without meaning to state the bleedin' obvious, but energy in > energy out.

The energy of an xray photon is proportional to the accelerated electron
voltage, which in most instances is proportional to V.

> So a 1-2 kV actual anode voltage (not power supply unloaded voltage)
> would not be an issue, unless you stick your nose constantly among the
> tubes, not recommended :-).
>
> Getting an electric shock in your nose is quite unpleasant and may
> affect concentration for a day. Done that, not recommended :-).

I have a vision of Jar Jar Binks in my mind after he paralysed his heads!


--
Mike Perkins
Video Solutions Ltd
www.videosolutions.ltd.uk

[upsid...@downunder.com]

Much of the 50/60 Hz hum problem is/was due to grounding practices,
especially with stage equipment.

- unbalanced signal connections were used
- the signal ground in each device was directly connected to chassis
- PE and N connected together into PEN in each mains socket ((TN-C)
(- SCR controlled stage lights connected to same mains feed, same PEN)

Fixing these problems helps solve a lot of hum problems on 50/60 Hz,
so why not on 400 Hz.

I admit that the ear is much more sensitive on 400 Hz than on 50/60
Hz, so more care is needed.

[Rob]

Listen on aircraft radio frequencies and you'll hear that 400Hz whine
on a lot of transmissions. With a little care it could probably be
avoided, but likely nobody cares as it isn't a safety issue.

When a similar system had 50/60Hz hum, you wouldn't even hear it as
the typical communication receiver has a high-pass to filter CTCSS
and the small speaker wouldn't do much at those frequencies.
Of course that isn't true for a stage audio system...

[Rob]

upsid...@downunder.com <upsid...@downunder.com> wrote:
> On Sat, 4 Aug 2018 23:29:23 -0500, "Tim Williams"
> <tiw...@seventransistorlabs.com> wrote:
>
>>Largest continuous duty, that's relevant to your application (i.e. not RF)
>>is the 8974, 1.5MW plate dissipation.
>
> RF tubes are OK as long as you can amplitude them.

Those RF power tetrodes have no problem with amplifying audio.
This is only an issue with resonating tubes like klystrons, magnetrons etc.

[Phil Allison]

upsid...@downunder.com wrote:

>
>
> Much of the 50/60 Hz hum problem is/was due to grounding practices,
> especially with stage equipment.
>
> - unbalanced signal connections were used
> - the signal ground in each device was directly connected to chassis
> - PE and N connected together into PEN in each mains socket ((TN-C)
> (- SCR controlled stage lights connected to same mains feed, same PEN)
>
> Fixing these problems helps solve a lot of hum problems on 50/60 Hz,
> so why not on 400 Hz.
>
> I admit that the ear is much more sensitive on 400 Hz than on 50/60
> Hz, so more care is needed.
>

** Annoying hum heard in live sound systems is at *many times* the local supply frequency. Typically a sharp buzz rather than a deep sine wave.

Radiation hum from nearby supply transformers into sensitive circuits like tape players and graphic eqs are only fixed by re-location of equipment - sometimes only a couple of rack heights ( 1.75 inches) does the trick.


.... Phil

[Chris Jones]

Yes, some sort of ion chamber should be ok too and maybe less hassle to
use. There are some designs on Charles Wenzel's site. But, some youtube
xray hobbyists use a metal envelope geiger counter that might be very
insensitive to <20keV photons.

[Chris Jones]

I have one of those, and the full scale is about 1/10th the lethal dose.
I guess it might be useful in a nuclear war.

[69883925...@nospam.org]

Yes, also known as nuclear war detector.
I have a bigger one too, with some ionisation chamber, that runs on a 1.5V D cell.
But these pens are plated with real gold!!!
Could not leave it there.
Then I have real GM counters, and a gamma spectrometer.
And know how to duck under the table in case the bomb goes off.
Nothing to worry about :-)

[bitrex]

"Bad Ground"

<https://www.youtube.com/watch?v=H09Mos2HLl8>

[69883925...@nospam.org]

I wrote

>Payed 10 Euro for the set.. Army surplus.
>Really nice stuff.
> http://217.120.43.67/nuclear/radiation_pen_IMG_6534.JPG

Here some more pictures,
The set, real gold plating!
the socket top right is where you plug in the pens to charge the electrometer.
http://217.120.43.67/nuclear/dosi_meter_PP-4127_IMG_3747.GIF

The circuit diagram, glued on the inside, really cool!
http://217.120.43.67/nuclear/dosi_meter_PP-4127_circuit_diagram_IMG_3737.GIF

The inside, even a spare bulb!
The bulb provides light so you can read the scales in the pen,
reading the pen against daylight works too.
http://217.120.43.67/nuclear/dosi_meter_meter_PP-4127_measurement_and_reset_unit_IMG_3734.JPG

[jurb...@gmail.com]

In the words of the late Steve Brown "Let's stop fistfucking around here and do it".

So make your own tube. I was thinking for the plate - a cement mixer. Chain link fence for a grid. Not sure about the cathode, whether to heat it with a LASER or acetylene.

Then you need to go to the nastiest bar in town and find some "boosters" who are people who will "obtain" things for you. Tell them to get you some of the transformers off the poles.

Then you take your pee wee 5,000 watt per channel amp and a transformer to drive the grids of the REAL output stage.

And don't worry about the missing transformer off the pole, make this thing run off 16 Kv directly. (or whatever voltage it is)

[Bert Hickman]

Heck, why stop at 16 kV? Tubes from these guys can run at 500 - 1200 kV:

https://www.slideshare.net/JohnKappenman/electron-tube-afs-epri-r5

[Jan Panteltje]

jurb6006 wrote

Long ago, in this group, same question was asked,
maybe by same OP?
Anyways same idea as you now come with was brought forward,
and I then proposed to heat the cathode with hot plutonium.

Maybe google still has it, otherwise I could search my own database for it.

OP is just a troll.

[Cursitor Doom]

On Tue, 07 Aug 2018 17:14:16 +0000, Jan Panteltje wrote:

> Anyways same idea as you now come with was brought forward,
> and I then proposed to heat the cathode with hot plutonium.

Well, I should imagine a scheme like that would introduce an unacceptable
amount of noise. ;-)
Nice to see you back, Jan!

[jurb...@gmail.com]

>"and I then proposed to heat the cathode with hot plutonium. "

Then it would need lead shielding. Too much work.

[Tim Williams]

<jurb...@gmail.com> wrote in message
news:ac36082f-19fa-46fa...@googlegroups.com...

> >"and I then proposed to heat the cathode with hot plutonium. "
>
> Then it would need lead shielding. Too much work.

Hardly: plutonium is primarily an alpha emitter. Also, he probably meant
Pu238, the stuff NASA uses in RTGs (or they did, back when there was
available production of the stuff), which is short enough lived to be useful
this way, and definitely all about the alphas. (If any other Pu were used,
it would have to be neutron based -- fission powered -- and in that case,
yes, it would be a steaming mess of radiation.)

The solution is foiled by a different mechanism. All those alphas have to
go somewhere, and a hot cathode guarantees thermal diffusion into the vacuum
is the primary route. You might get an unreliable gas rectifier or
thyratron, but not a usable vacuum triode or the like. :-/

[Tim Williams]

"Bert Hickman" <bert-h...@comcast.net> wrote in message
news:JNGdnVGkQLezT_TG...@giganews.com...

> Heck, why stop at 16 kV? Tubes from these guys can run at 500 - 1200 kV:
>
> https://www.slideshare.net/JohnKappenman/electron-tube-afs-epri-r5

I've always wondered what the plate curves of those things look like. They
make extraordinary claims. I don't see how they're going to get a low
voltage drop for switching operations.

As we still don't have cold-cathode 300Bs in TO-247 packages, I have other
doubts about such technology; but, given that these are very much in the
domain of military secrets and "munitions", I can see there might be reason
for that. (Speaking of EMP protection, you could just as well wire one as a
blocking oscillator and generate an offensive quantity of ESD, intense
enough to be called EMP as such.)

[tabb...@gmail.com]

On Wednesday, 8 August 2018 01:29:37 UTC+1, Tim Williams wrote:
> <jurb...@gmail.com> wrote in message
> news:ac36082f-19fa-46fa...@googlegroups.com...

> > >"and I then proposed to heat the cathode with hot plutonium. "
> >
> > Then it would need lead shielding. Too much work.
>
> Hardly: plutonium is primarily an alpha emitter. Also, he probably meant
> Pu238, the stuff NASA uses in RTGs (or they did, back when there was
> available production of the stuff), which is short enough lived to be useful
> this way, and definitely all about the alphas. (If any other Pu were used,
> it would have to be neutron based -- fission powered -- and in that case,
> yes, it would be a steaming mess of radiation.)
>
> The solution is foiled by a different mechanism. All those alphas have to
> go somewhere, and a hot cathode guarantees thermal diffusion into the vacuum
> is the primary route. You might get an unreliable gas rectifier or
> thyratron, but not a usable vacuum triode or the like. :-/
>
> Tim

If you're chucking out a megawatt you can afford to include a vacuum pump in he amp.


NT

[jurb...@gmail.com]

>"All those alphas have to
go somewhere, and a hot cathode guarantees thermal diffusion into the vacuum
is the primary route."

Yeah, and thinking abut it, acetylene would throw a bunch of CO2 in there unless it was some sort of heat exchanger. Maybe a tubular type such as used in modern furnaces.

Probably easier to just use a LASER.

Actually tubing could be filled with pumped coolant and a simple current passed to radiate the heat. Works at the Tokamak.

[69883925...@nospam.org]

On a sunny day (Tue, 7 Aug 2018 19:29:36 -0500) it happened "Tim Williams"
<tiw...@seventransistorlabs.com> wrote in <pkddhd$l90$1...@dont-email.me>:

><jurb...@gmail.com> wrote in message
>news:ac36082f-19fa-46fa...@googlegroups.com...
>> >"and I then proposed to heat the cathode with hot plutonium. "
>>
>> Then it would need lead shielding. Too much work.
>
>Hardly: plutonium is primarily an alpha emitter. Also, he probably meant
>Pu238, the stuff NASA uses in RTGs (or they did, back when there was
>available production of the stuff), which is short enough lived to be useful
>this way, and definitely all about the alphas. (If any other Pu were used,
>it would have to be neutron based -- fission powered -- and in that case,
>yes, it would be a steaming mess of radiation.)
>
>The solution is foiled by a different mechanism. All those alphas have to
>go somewhere, and a hot cathode guarantees thermal diffusion into the vacuum
>is the primary route. You might get an unreliable gas rectifier or
>thyratron, but not a usable vacuum triode or the like. :-/
>
>Tim

Use an indirectly heated cathode.

[jurb...@gmail.com]

>"Use an indirectly heated cathode. "

A LASER is indirect.

[Tim Williams]

<jurb...@gmail.com> wrote in message
news:d4d7b13b-7752-4778...@googlegroups.com...

> >"Use an indirectly heated cathode. "
>
> A LASER is indirect.

Unless it's direct:
https://www.nature.com/articles/ncomms13399