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Re: What is the most powerful vacuum tube ever made?
On 08/03/2018 11:45 AM, Rob wrote:
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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.

Re: What is the most powerful vacuum tube ever made?
On 3.8.18 18:49, bitrex wrote:
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To stay in the style: A sturdy transformer, some mercury-arc rectifiers,
a hefty swinging choke and a bunch of oil capacitors.

--  

-TV


Re: What is the most powerful vacuum tube ever made?
On 08/03/2018 12:56 PM, Tauno Voipio wrote:
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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.

Re: What is the most powerful vacuum tube ever made?
On 08/03/2018 12:56 PM, Tauno Voipio wrote:
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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.

Re: What is the most powerful vacuum tube ever made?
On Fri, 3 Aug 2018 19:56:48 +0300, Tauno Voipio

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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)..


Re: What is the most powerful vacuum tube ever made?
On Friday, 3 August 2018 22:36:32 UTC+1, snipped-for-privacy@downunder.com  wrote:
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the efficiency of those things is crappy, you'd lose nearly half the power in it.


NT

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

Re: What is the most powerful vacuum tube ever made?
On Saturday, 4 August 2018 08:26:06 UTC+1, Rob  wrote:
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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.


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Sure, but he specifically wants valves & analogue.


NT

Re: What is the most powerful vacuum tube ever made?
On 4.8.18 00:37, snipped-for-privacy@downunder.com wrote:
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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

Re: What is the most powerful vacuum tube ever made?
On Sat, 4 Aug 2018 10:58:35 +0300, Tauno Voipio

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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.
  

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

Re: What is the most powerful vacuum tube ever made?
snipped-for-privacy@downunder.com wrote:

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** 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

Re: What is the most powerful vacuum tube ever made?
On 08/06/2018 05:36 AM, Phil Allison wrote:
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"Bad Ground"

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



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

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

Re: What is the most powerful vacuum tube ever made?
whit3rd wrote:

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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

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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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

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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     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: What is the most powerful vacuum tube ever made?

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

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




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

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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.


Re: What is the most powerful vacuum tube ever made?
On Sat, 04 Aug 2018 06:52:49 +0300, snipped-for-privacy@downunder.com wrote:

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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.

--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
We've slightly trimmed the long signature. Click to see the full one.

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