What is the most powerful vacuum tube ever made?

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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).



Re: What is the most powerful vacuum tube ever made?
snipped-for-privacy@tubes.com says...
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Water-cooled loudspeakers?

Mike.

Re: What is the most powerful vacuum tube ever made?
On Fri, 03 Aug 2018 07:34:12 +0100, Mike Coon wrote:

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 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

Re: What is the most powerful vacuum tube ever made?
On Fri, 03 Aug 2018 01:07:29 -0500, snipped-for-privacy@tubes.com wrote:

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

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What is the frequency response of a pole pig transformer ?

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


Re: What is the most powerful vacuum tube ever made?
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Any idea yet what you wil say through that PA?
And who the victims will be?


Re: What is the most powerful vacuum tube ever made?
On 3.8.18 09:07, snipped-for-privacy@tubes.com wrote:
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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

Re: What is the most powerful vacuum tube ever made?
Tauno Voipio wrote:

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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


Re: What is the most powerful vacuum tube ever made?
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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.

Re: What is the most powerful vacuum tube ever made?
On 3.8.18 11:28, Rob wrote:
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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


Re: What is the most powerful vacuum tube ever made?
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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?

Re: What is the most powerful vacuum tube ever made?
On 3.8.18 15:12, Rob wrote:
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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

Re: What is the most powerful vacuum tube ever made?
fredag den 3. august 2018 kl. 15.20.48 UTC+2 skrev Tauno Voipio:
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https://www.cpii.com/docs/datasheets/78/8974.pdf


Re: What is the most powerful vacuum tube ever made?
On Fri, 3 Aug 2018 16:20:43 +0300, Tauno Voipio

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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.


Re: What is the most powerful vacuum tube ever made?
On 3.8.18 16:48, snipped-for-privacy@downunder.com wrote:
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Pori has been down since over a decade ago, see:
<https://yle.fi/uutiset/osasto/news/yle_ends_short_wave_broadcasts/5756519 .

--  

-TV


Re: What is the most powerful vacuum tube ever made?
On Fri, 3 Aug 2018 19:50:08 +0300, Tauno Voipio

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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.


Re: What is the most powerful vacuum tube ever made?
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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?

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It is my guess too.

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

Re: What is the most powerful vacuum tube ever made?
Tauno Voipio wrote:

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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/ snipped-for-privacy@2x.jpg

    Best regards, Piotr

Re: What is the most powerful vacuum tube ever made?
On 4.8.18 12:01, Piotr Wyderski wrote:
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It was the exchange of the guy ropes going awry.

--  

-TV


Re: What is the most powerful vacuum tube ever made?
Tauno Voipio wrote:

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

    Best regards, Piotr




Re: What is the most powerful vacuum tube ever made?
On Fri, 03 Aug 2018 01:07:29 -0500, snipped-for-privacy@tubes.com wrote:

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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.


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