What is the most powerful vacuum tube ever made?

On Sat, 04 Aug 2018 06:52:49 +0300, upsidedown@downunder.com wrote:

>On Fri, 03 Aug 2018 18:54:10 -0700, Jeff Liebermann <jeffl@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.

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

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.

tabbypurr@gmail.com <tabbypurr@gmail.com> 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.voipio@notused.fi.invalid> wrote:
>> >On 3.8.18 18:49, bitrex wrote:
>> >> On 08/03/2018 11:45 AM, Rob wrote:
>> >>> bitrex <user@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.
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%.

On 4.8.18 00:37, upsidedown@downunder.com wrote:
> On Fri, 3 Aug 2018 19:56:48 +0300, Tauno Voipio
> <tauno.voipio@notused.fi.invalid> wrote:
> 
>> On 3.8.18 18:49, bitrex wrote:
>>> On 08/03/2018 11:45 AM, Rob wrote:
>>>> bitrex <user@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)..


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

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

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/2017/11/2-22-300x225@2x.jpg

	Best regards, Piotr

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

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

On Fri, 03 Aug 2018 01:07:29 -0500, oldschool@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.
https://www.avast.com/antivirus

On Saturday, 4 August 2018 08:26:06 UTC+1, Rob  wrote:
> tabbypurr@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.voipio@notused.fi.invalid> wrote:
> >> >On 3.8.18 18:49, bitrex wrote:
> >> >> On 08/03/2018 11:45 AM, Rob wrote:
> >> >>> bitrex <user@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