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  #1   Report Post  
Iain M Churches
 
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Default Kilovolt transmitting tubes


"Andre Jute" wrote in message
...
rec.audio.tubes

Kilovolt transmitting tubes


Let's make a new thread here.

Now we are back on track. This is the kind of stuff
RAT needs and is famous for:-)

Iain


  #2   Report Post  
Chad Wahls
 
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"Iain M Churches" wrote in message
...

"Andre Jute" wrote in message
...
rec.audio.tubes

Kilovolt transmitting tubes


Let's make a new thread here.

Now we are back on track. This is the kind of stuff
RAT needs and is famous for:-)

Iain


http://216.87.144.102/svetlana/techbulletins.asp

I liked 38 but the link seems down now.

Chad


  #3   Report Post  
Patrick Turner
 
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Iain M Churches wrote:

"Andre Jute" wrote in message
...
rec.audio.tubes

Kilovolt transmitting tubes


Let's make a new thread here.

Now we are back on track. This is the kind of stuff
RAT needs and is famous for:-)

Iain


One needs a special respect for working with
1,000v+ anode voltages.

Its a wonder more ppl have not been killed....

The OPTs for such wonders do take quite some careful
consideration, especially with SE or PP 211,
because the load value is high, and the C shunt
begins to have effects, so there has to be thick insulation.
But the HV dictates thick insulation, and preferably
potting the OPT in a can with oil and sealed terminals.

An old friend has an ex WW2 transmitter with
2,500v and a pair of 813.
Many older hams had RF finals with a lot of voltage.

I have been reluctant to make audio amps with such high voltages for
sale to the general public.

The 833 has interesting possibilities, but it is a queer triode,
with pentode like curves and high Ra.

If I wanted to start with a HV tube, I'd use an 845.

Or a pair in PP; they'd be awesome.

Patrick Turner.




  #4   Report Post  
Iain M Churches
 
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"Patrick Turner" wrote in message
...
One needs a special respect for working with
1,000v+ anode voltages.

Its a wonder more ppl have not been killed....


This M50 monobloc has the highest B+ of any
amp I have constructed (500VC)

I treat it with great respectm and work only two hours
at a time.

Iain


  #5   Report Post  
 
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You are more likely to be killed outright by line voltage than by high
B+. 70 years of Amateur Radio statistics-most of which time hams were
mostly builders-bears this out.

Design commercial products with interlocks like transmitter
manufacturers did for years and if you are a DIYer buy and/or build
proper safety equipment and use it.

Tube amps running 1 kV and above are the best sounding and most
reliable-they either are built properly or fail spectacularly and in
short order-way to get substantial power. The 812, 813, and a bunch of
other tubes out there can sound great and give good service. You have
to put some build cost in the amp, which is as it should be.



  #6   Report Post  
Fabio Berutti
 
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If You want a tube for "real men", see this one:

http://info.uibk.ac.at/c/c7/c704/mus...es/rs329g.html

Some are still available in Germany...

Back to more palatable tubes, and considering that original 211s or 845s are
hard to find or extremely expensive, my favorite tube in this league would
be the Russian GM-70. It has a dissipation of 125W, a higher mu than the
845 and it doesn't need to be "swung" up to positive grid for full power
like a 211, ie. the driver circuit task is easier and the final result is
probably better. I played a bit with the anode curves and it seems that a
B+ of about 1000 - 1100V together with an anode load of 10K gives the
maximum output power in SE class A, about 45W!
Or put a pair of them in PP to blast the roof...

Happy to see a real RAT thread

Ciao

Fabio


"Andre Jute" ha scritto nel messaggio
...
rec.audio.tubes

Kilovolt transmitting tubes



Let's make a new thread here.



Chris Hornbeck wrote:



I'm a big fan of 845's; they solve a lot of speaker problems,


which are much more intractible. 211's have even better curves,


and three in parallel make 50 watts without grid current,


and into an almost-practical 5K ohm load.




Back in the 60s, when I was a student, I travelled across the States on
one
of those go anywhere one way Greyhound tickets that then cost 99 bucks.
(Somebody
said a couple of years ago that they are still only 199 bucks.
Extraordinary
value.) I spent months on the buses, meeting people. In the first week I
won
a Sony radio in a game of dice with some black men who said they were
union
organizers. When I observed that they gambled recklessly, one of them
said,
"Man, this is Charleston and the white boy thinks black union men gamble
recklessly!"
On the Sony, when there was no one to talk to, I tuned in to the smoky AM
jazz
stations that then abounded. They played real jazz, with harmony and
melody
and invention; the self-indulgent **** you hear today says absolutely
nothing
to me except that the socalled artist is committing onanism in public when
I would much prefer it to be hara kiri. Later I heard those stations used
845s in their transmitters. So when the opportunity arose, I built some
845s.
I have never ceased to love their sound.



The 211 I like much less. To me its only advantage is an easier drive
requirement,
which becomes irrelevant once you decide on a triode power tube with a
good
bit of current on it as your driver. I typically expect Americans to like
211
sound.



Tubes sonically somewhere in between are the Svetlana 572-3 and -10, with
the
-30 not quite so refined.



My Type 199 Millennium End amp is a Svetlana 572-xx switchable SE, PSE amp
of up to 75W (theoretically more but I've never bothered, in fact I mostly
use it set up for the 25W region). The KISS Amp design that I am waiting
to
resume describing is a version of the booster amp driving the Millennium.
That's
right, I use a WE300B as a pre-amp for a bigger amp.



You say "an almost-practical 5K ohm load". If you merely mean availability
of transformers, it is perfectly practical. The transformers designed for
my
T199 by Menno van der Veen are catalogued by Amplimo and Plitron. The
output
is rated of 90W, 190mA (design centre, 380mA in all), primary 5K014, and
has
secondary links 2, 4 and 8ohm to permit use of one or two SV-572-3 or -10,
or two 845, or the three parallel 211 you posit, i.e. 2K5 or 5K. The power
supply after rectifying gives a kilovolt at 200mA, 950V at 400mA, and also
has separate windings for the drivers, input tubes, bias, filaments. I use
the prototypes Menno tested for the formal description. The numbers of the
prototypes, which should permit you to find them in the Plitron and
Amplimo
catalogues, are output VDV-JUTE-HQ5090 and power supply 6632-XO. Both
firms
wind both transformers. Amplimo is in The Netherlands, Plitron in Canada.
Sit
down before you read the prices and the shipping weights. These are
monsters
probably on the very edge of feasibility for amateurs (though not by the
standards
of the more experienced radio hams).



You wouldn't happen to have a pair of 212-E for sale or trade, would you,
my
dear fellow? I have just the transformers for them already... One of the
design
specs I gave Menno was my dream of 212-E, so he returned ultra-useful
experimenter's
trannies.



Coming back for a moment to your 3x 211. At a 1000V on the plate, a 211
has
a plate resistance of around 3800 ohm. Three in parallel would show Rp a
bit
under 1300R. My experience is that you want a higher multiple of Rp for RL
on 211 than on 845, or, put more positively, 845 are more tolerant while
211
repay higher multiples. (That is why Kondo went to such extraordinary
lengths
with the output for the Ongaku, claimed to be 20K but reputedly at least
16K.)
Four times a bit under 1300R is 5K1 so you will do the job handsomely with
these trannies. On the other hand, with so much current capability in the
OPT,
you can run the 211 high and hot, somewhere over 60mA, and gain some more
silence
from that.



HTH.



Andre Jute



PS. The rest of you reckless little *******s, don't start building
kilovolt
amps before you have built several EL34 or 300B amps and run them for a
couple
of years without mishap. It's not just a different ballgame, it is on a
different
level altogether. Think permanent state of death (a morbid joke I'm
borrowing
from the novelist John Gardner) and ask yourself if you really want to
take
a fulltime holiday there. The most common UL rating for tube amp wire,
1015,
is happy with 300B voltages but not suitable for kilovolt amps; the same
applies
to caps which need bypasses if stacked, and resistors have to be specially
rated. *Everything* you use in a kilovolt amp has to be inspected with a
jaundiced
eye, and you can't even measure it with the sort of meter you until now
thought
expensive or, very probably, the scope on your workbench; the reduction
probe
you bought for 80 bucks is most probably illegal and dangerous for such
elevated
voltages. (I don't just mean the digital or silicon electronics stuff
rated
30 or 50V; a lot of common good quality high tension gear is rated 600V
max.
Always check the fuse rating inside the meter.) Just for the record, by
kilovolt
amps I mean a kilovolt and over, because the 845/211 class is rated for
1250
volts, and some other tubes we discussed or may still discuss much higher
still.




  #7   Report Post  
tony sayer
 
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In article , Patrick Turner
writes


Iain M Churches wrote:

"Andre Jute" wrote in message
...
rec.audio.tubes

Kilovolt transmitting tubes


Let's make a new thread here.

Now we are back on track. This is the kind of stuff
RAT needs and is famous for:-)

Iain


One needs a special respect for working with
1,000v+ anode voltages.

Its a wonder more ppl have not been killed....


Well when I used to work for the old Pye Television Transmitter company
they had Klystrons in the UHF Tx's, some 15 kV on the collectors, and
all that was in UR67 co-ax with the screens well earthed!.

All the caps and suchlike had large knife switches that were used for
grounding after the power was switched off. The whole lot was controlled
by a A and B key system in that a number of the B keys could open the
various cabinets but in doing so they were retained in the locks until
closed with an elaborate system of switched interlocks. Only when all
the B keys were back in the frame that they stayed locked into, could
you take the A key out to lift off the earths and turn on the power.

In a remote part of Indonesia some maintenance engineer found it
expedient to have a spare A key, he got a local locksmith to make up.
Needless to say in that country the TX sites were a bit remote so it
wasn't unusual for an engineer to go missing for a few days, which he
did, and after a few more days than usual, they went looking.

They found him, or what was left of him, in a high voltage cubicle and
the body had much of its flesh removed by animals and insects;(
proved that the companies insistence on NO spare A keys was a good
thing!.....

--
Tony Sayer

  #9   Report Post  
tony sayer
 
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In article , Andre Jute
writes
rec.audio.tubes

Kilovolt transmitting tubes



Let's make a new thread here.



Chris Hornbeck wrote:



I'm a big fan of 845's; they solve a lot of speaker problems,


which are much more intractible. 211's have even better curves,


and three in parallel make 50 watts without grid current,


and into an almost-practical 5K ohm load.




Back in the 60s, when I was a student, I travelled across the States on one
of those go anywhere one way Greyhound tickets that then cost 99 bucks.
(Somebody
said a couple of years ago that they are still only 199 bucks. Extraordinary
value.) I spent months on the buses, meeting people. In the first week I won
a Sony radio in a game of dice with some black men who said they were union
organizers. When I observed that they gambled recklessly, one of them said,
"Man, this is Charleston and the white boy thinks black union men gamble
recklessly!"



On the Sony, when there was no one to talk to, I tuned in to the smoky AM jazz
stations that then abounded. They played real jazz, with harmony and melody
and invention; the self-indulgent **** you hear today says absolutely nothing
to me except that the socalled artist is committing onanism in public when
I would much prefer it to be hara kiri. Later I heard those stations used
845s in their transmitters. So when the opportunity arose, I built some 845s.
I have never ceased to love their sound.



So sad to say that most MF transmitters these days are solid state in
the modulators;( Apart from that theres no buddy Jazz stations on
British radio to speak of anyway,

So much for "broadening listener choice" OFCOM;((
--
Tony Sayer

  #10   Report Post  
tony sayer
 
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Default

In article , Andre Jute
writes
rec.audio.tubes

Kilovolt transmitting tubes



Let's make a new thread here.



Chris Hornbeck wrote:



I'm a big fan of 845's; they solve a lot of speaker problems,


which are much more intractible. 211's have even better curves,


and three in parallel make 50 watts without grid current,


and into an almost-practical 5K ohm load.




Back in the 60s, when I was a student, I travelled across the States on one
of those go anywhere one way Greyhound tickets that then cost 99 bucks.
(Somebody
said a couple of years ago that they are still only 199 bucks. Extraordinary
value.) I spent months on the buses, meeting people. In the first week I won
a Sony radio in a game of dice with some black men who said they were union
organizers. When I observed that they gambled recklessly, one of them said,
"Man, this is Charleston and the white boy thinks black union men gamble
recklessly!"
On the Sony, when there was no one to talk to, I tuned in to the smoky AM jazz
stations that then abounded. They played real jazz, with harmony and melody
and invention; the self-indulgent **** you hear today says absolutely nothing
to me except that the socalled artist is committing onanism in public when
I would much prefer it to be hara kiri. Later I heard those stations used
845s in their transmitters. So when the opportunity arose, I built some 845s.
I have never ceased to love their sound.


So sad to say that most MF transmitters these days are solid state in
the modulators;( Apart from that theres no bluddy Jazz stations on
British radio to speak of anyway,

So much for "broadening listener choice" OFCOM;((
--
Tony Sayer



  #11   Report Post  
Tom Schlangen
 
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Waiting for Nick Sheldon to join this article thread ... :-)

Tom

--
Do not meddle in the affairs of wizards,
for you are crunchy and good with ketchup.
  #12   Report Post  
robert casey
 
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Default




One needs a special respect for working with
1,000v+ anode voltages.


Then there are tubes like the 6BK4, intended as color
TV set very high voltage voltage regulators. 25KV. It's
a triode with a mu of 2000. Heard some people
use them in audio amps. Electrostatic speaker drivers?

  #13   Report Post  
robert casey
 
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Default



One needs a special respect for working with
1,000v+ anode voltages.

Its a wonder more ppl have not been killed....

Another thing, it would be mandatory that the tubes
be fully enclosed in a cage, and that cage and the
bottom lid of the amp have interlocks to disable
the power supply if opened. No pretty wood boxes
with bare tubes on top. You can chrome or gold plate
the cage if you want to make it look pretty....
  #14   Report Post  
Choky
 
Posts: n/a
Default


"Andre Jute" wrote in message
...

you arrogant ****head;

my job ( amongst others) in local radio station is to maintenance tube FM
transmitter with 1,5KW output,and working voltage in range of 2KV.
and that's Lilliput type of facility in this sort of business.
betcha you never walked through transmitter?
imagine that sort of energy,and imagine that sort of brain muscles needed to
make that gadgets.
pity,mebbe your arrogance will be smaller .........

man with brain and with balls can do that without polluting newsgroups.
in any case-man with real job and proper attitude to life will never spill
**** in NG ,like you do all the time.

"c'mon-make my day".


--
--
.................................................. ........................
Choky
Prodanovic Aleksandar
YU

"don't use force, "don't use force,
use a larger hammer" use a larger tube
- Choky and IST"
- ZM
.................................................. ...........................



  #15   Report Post  
Dave Plowman (News)
 
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In article ,
Iain M Churches wrote:
rec.audio.tubes

Kilovolt transmitting tubes


Let's make a new thread here.

Now we are back on track. This is the kind of stuff
RAT needs and is famous for:-)


Some might say it's in the realms of green pens for CDs and litz wire for
speakers. :-)

--
*Heart attacks... God's revenge for eating his animal friends

Dave Plowman London SW
To e-mail, change noise into sound.


  #16   Report Post  
Jim Gregory
 
Posts: n/a
Default

In the late 50s and early 60s I was a Rediffusion trainee learning about
high voltage (B+ of 1.6kV )audio amps. These were made by Redifon - and the
older ones running 4 huge tetrodes with forced cold air intake gave nearly
2.5kW each (x eight in sync), while the newer ones with 4 later tubes in
air-conned cabinets pushed out 3kW (x four in sync), both programmes into
100V line feeders which was copper-quad distributed PA-fashion over 120
square miles, to over 40,000 home subscribers, each with a channel select
switch and a variable attenuator giving, after step-down to 15Ohm
loudspeaker, about a 1/2 Watt either channel. Tubes started going soft about
ten months of 18-hr use. I think they contained some mercury coatings, or
something like that.
807s fed them, again at a high voltage, I think about 600V, on topcaps.
The quality was superb... up to about 15kHz (-3dB point) on homes nearer to
our station, up to10 kHz on outer radius of network. Xtalk, on a dry day,
was better than 35dB below ref (43dB below peak).
The cabinets were interlocked on all access doors, had isolation breakers on
their o/ps, needed 2 mins for heaters to warm up, and the EHT capacitors
with a bleeder across still held juice after 2 hours. Had to shunt their
electrodes with a screwdriver before any corona cleaning or maint work could
be done! I recall those large coupling transformer (14" cubed) laminations
chattered and sang tizzily, just like a Personal stereo sounds to another
individual.

"tony sayer" wrote in message
...
In article .com,
writes
You are more likely to be killed outright by line voltage than by high
B+. 70 years of Amateur Radio statistics-most of which time hams were
mostly builders-bears this out.

Design commercial products with interlocks like transmitter
manufacturers did for years and if you are a DIYer buy and/or build
proper safety equipment and use it.

Tube amps running 1 kV and above are the best sounding and most
reliable-they either are built properly or fail spectacularly and in
short order-way to get substantial power. The 812, 813, and a bunch of
other tubes out there can sound great and give good service. You have
to put some build cost in the amp, which is as it should be.


We used to make IIRC 2-5 kW amps for the old Pamphonic company sometime
in the late Sixties, can't for the life of me remember the Valves used
something like PA100 or similar. Bloody great things, about a foot and a
bit high!....
--
Tony Sayer



  #17   Report Post  
Chris Hornbeck
 
Posts: n/a
Default

On 15 Mar 2005 14:07:20 -0000, Andre Jute
wrote:

The 211 I like much less. To me its only advantage is an easier drive requirement,
which becomes irrelevant once you decide on a triode power tube with a good
bit of current on it as your driver. I typically expect Americans to like 211
sound.


You could also look at its drive requirement as a negative, both
because of the higher Miller C and because of the great temptation
to try to drive them into grid current. Their load impedance
requirements are a bear too, and only eased by paralleling.

The things that I *like* about 211's are their exceptional
linearity, uniformity (if using GE's or RCA's) and the fact
that I have a couple dozen on hand.


Tubes sonically somewhere in between are the Svetlana 572-3 and -10, with the
-30 not quite so refined.


Never used them, although I remember your positive comments
from several years ago.


You wouldn't happen to have a pair of 212-E for sale or trade, would you, my
dear fellow? I have just the transformers for them already... One of the design
specs I gave Menno was my dream of 212-E, so he returned ultra-useful experimenter's
trannies.


Sorry, I've never owned even one. Wish I had a pair now; I wouldn't
have to work for a living.


Coming back for a moment to your 3x 211. At a 1000V on the plate, a 211 has
a plate resistance of around 3800 ohm. Three in parallel would show Rp a bit
under 1300R. My experience is that you want a higher multiple of Rp for RL
on 211 than on 845, or, put more positively, 845 are more tolerant while 211
repay higher multiples. (That is why Kondo went to such extraordinary lengths
with the output for the Ongaku, claimed to be 20K but reputedly at least 16K.)
Four times a bit under 1300R is 5K1 so you will do the job handsomely with
these trannies. On the other hand, with so much current capability in the OPT,
you can run the 211 high and hot, somewhere over 60mA, and gain some more silence
from that.


Very well put; covers it.

One avenue I've yet to explore is directly driving electrostats with
a push-pull pair of "50 watters". Even a single pair of 211's would be
enough for the old QUAD's, methinks.

Thanks for your thoughts,

Chris Hornbeck
"That's where may forebears came from. Three of them
anyway. Who's been sleeping in my porridge?" -F&S
  #18   Report Post  
John Stewart
 
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Default

Andre Jute wrote:

rec.audio.tubes

Kilovolt transmitting tubes

Let's make a new thread here.

Chris Hornbeck wrote:

I'm a big fan of 845's; they solve a lot of speaker problems,


which are much more intractible. 211's have even better curves,


and three in parallel make 50 watts without grid current,


and into an almost-practical 5K ohm load.


Back in the 60s, when I was a student, I travelled across the States on one
of those go anywhere one way Greyhound tickets that then cost 99 bucks. (Somebody
said a couple of years ago that they are still only 199 bucks. Extraordinary
value.) I spent months on the buses, meeting people. In the first week I won
a Sony radio in a game of dice with some black men who said they were union
organizers. When I observed that they gambled recklessly, one of them said,
"Man, this is Charleston and the white boy thinks black union men gamble recklessly!"
On the Sony, when there was no one to talk to, I tuned in to the smoky AM jazz
stations that then abounded. They played real jazz, with harmony and melody
and invention; the self-indulgent **** you hear today says absolutely nothing
to me except that the socalled artist is committing onanism in public when
I would much prefer it to be hara kiri. Later I heard those stations used
845s in their transmitters. So when the opportunity arose, I built some 845s.
I have never ceased to love their sound.

The 211 I like much less. To me its only advantage is an easier drive requirement,
which becomes irrelevant once you decide on a triode power tube with a good
bit of current on it as your driver. I typically expect Americans to like 211
sound.

Tubes sonically somewhere in between are the Svetlana 572-3 and -10, with the
-30 not quite so refined.

My Type 199 Millennium End amp is a Svetlana 572-xx switchable SE, PSE amp
of up to 75W (theoretically more but I've never bothered, in fact I mostly
use it set up for the 25W region). The KISS Amp design that I am waiting to
resume describing is a version of the booster amp driving the Millennium. That's
right, I use a WE300B as a pre-amp for a bigger amp.

You say "an almost-practical 5K ohm load". If you merely mean availability
of transformers, it is perfectly practical. The transformers designed for my
T199 by Menno van der Veen are catalogued by Amplimo and Plitron. The output
is rated of 90W, 190mA (design centre, 380mA in all), primary 5K014, and has
secondary links 2, 4 and 8ohm to permit use of one or two SV-572-3 or -10,
or two 845, or the three parallel 211 you posit, i.e. 2K5 or 5K. The power
supply after rectifying gives a kilovolt at 200mA, 950V at 400mA, and also
has separate windings for the drivers, input tubes, bias, filaments. I use
the prototypes Menno tested for the formal description. The numbers of the
prototypes, which should permit you to find them in the Plitron and Amplimo
catalogues, are output VDV-JUTE-HQ5090 and power supply 6632-XO. Both firms
wind both transformers. Amplimo is in The Netherlands, Plitron in Canada. Sit
down before you read the prices and the shipping weights. These are monsters
probably on the very edge of feasibility for amateurs (though not by the standards
of the more experienced radio hams).

You wouldn't happen to have a pair of 212-E for sale or trade, would you, my
dear fellow? I have just the transformers for them already... One of the design
specs I gave Menno was my dream of 212-E, so he returned ultra-useful experimenter's
trannies.

Coming back for a moment to your 3x 211. At a 1000V on the plate, a 211 has
a plate resistance of around 3800 ohm. Three in parallel would show Rp a bit
under 1300R. My experience is that you want a higher multiple of Rp for RL
on 211 than on 845, or, put more positively, 845 are more tolerant while 211
repay higher multiples. (That is why Kondo went to such extraordinary lengths
with the output for the Ongaku, claimed to be 20K but reputedly at least 16K.)
Four times a bit under 1300R is 5K1 so you will do the job handsomely with
these trannies. On the other hand, with so much current capability in the OPT,
you can run the 211 high and hot, somewhere over 60mA, and gain some more silence
from that.

HTH.

Andre Jute

PS. The rest of you reckless little *******s, don't start building kilovolt
amps before you have built several EL34 or 300B amps and run them for a couple
of years without mishap. It's not just a different ballgame, it is on a different
level altogether. Think permanent state of death (a morbid joke I'm borrowing
from the novelist John Gardner) and ask yourself if you really want to take
a fulltime holiday there. The most common UL rating for tube amp wire, 1015,
is happy with 300B voltages but not suitable for kilovolt amps; the same applies
to caps which need bypasses if stacked, and resistors have to be specially
rated. *Everything* you use in a kilovolt amp has to be inspected with a jaundiced
eye, and you can't even measure it with the sort of meter you until now thought
expensive or, very probably, the scope on your workbench; the reduction probe
you bought for 80 bucks is most probably illegal and dangerous for such elevated
voltages. (I don't just mean the digital or silicon electronics stuff rated
30 or 50V; a lot of common good quality high tension gear is rated 600V max.
Always check the fuse rating inside the meter.) Just for the record, by kilovolt
amps I mean a kilovolt and over, because the 845/211 class is rated for 1250
volts, and some other tubes we discussed or may still discuss much higher still.


In the late 50's, I built a 4500 volt, one amp DC regulated PS. The passer tubes were
304TH's, so I guess that would qualify to be in this thread. It was pretty damned
impressive with lots of interlocks. That was fortunate one time when the run contacts on
the line relay failed to open. They were welded shut by the inrush on start. The fail
safe system discharged 8 microfarads of cap at more than 5KV with a huge bang.

Lucky ME. JLS

  #19   Report Post  
Nick Gorham
 
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Default

Fabio Berutti wrote:
If You want a tube for "real men", see this one:

http://info.uibk.ac.at/c/c7/c704/mus...es/rs329g.html

Some are still available in Germany...

Back to more palatable tubes, and considering that original 211s or 845s are
hard to find or extremely expensive, my favorite tube in this league would
be the Russian GM-70. It has a dissipation of 125W, a higher mu than the
845 and it doesn't need to be "swung" up to positive grid for full power
like a 211, ie. the driver circuit task is easier and the final result is
probably better. I played a bit with the anode curves and it seems that a
B+ of about 1000 - 1100V together with an anode load of 10K gives the
maximum output power in SE class A, about 45W!
Or put a pair of them in PP to blast the roof...

Happy to see a real RAT thread

Ciao

Fabio


As it happens, I missed most of this thread, as I spent yesterday
listening and "playing" about with a pair of 212's descrovering that
they take quite a lot to drive properly.

We did some blind comparisons some time back, and the graphite GM70
didn't come out as well as others. The copper plate GM70 on the other
hand, sounded very similar to a pair of 4212, and a pair of vt1505's.

Having said that I have used a GM70 for a few months and it sounded
good. And nice and easy to drive. Works quite well at lowish voltage as
well 800v @100ma or so.

Though to my ears, I prefer the 211. Both the GM70 and 845 are more
"mechanical" sounding, this is of course just IMHO.

--
Nick

"Life has surface noise" - John Peel 1939-2004
  #20   Report Post  
Iain M Churches
 
Posts: n/a
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"Dave Plowman (News)" wrote in message
...
In article ,
Iain M Churches wrote:
Now we are back on track. This is the kind of stuff
RAT needs and is famous for:-)


Some might say it's in the realms of green pens for CDs and litz wire for
speakers. :-)

No, this is the real thing:-))

Iain




  #21   Report Post  
Iain M Churches
 
Posts: n/a
Default


"robert casey" wrote in message
nk.net...


One needs a special respect for working with
1,000v+ anode voltages.

Its a wonder more ppl have not been killed....

Another thing, it would be mandatory that the tubes
be fully enclosed in a cage,


It is, for any valve amp, at least here in Scandinavia.
If the owner removed the cage supplied, he does so at
his own risk - just like removing the guard from an
industrial saw. The risk of fire, or a child burning
him/herself, although small, is statistically greater than
electrocution.

I have seen some American amps with a two way mains
cord (probably not allowed any more) Here, a three way
cord is required, with the amp chassis bonded to ground.
Fixed mains cables are no longer allowed, neither is the
octal plug/socket for high voltage AC or DC. The only
approved mains chassis connectors are the IEC,
and the Speakon AC connector.

and that cage and the
bottom lid of the amp have interlocks to disable
the power supply if opened.


The safety regs here insist that a separate psu has an
interlock, and removing the umbilical cord from psu to
amp from either end, shuts the psu down, and
discharges it, in a time shorter than that required to
remove the bottom plate to gain access. Also, high
voltage DC is not allowed to be carried on an umbilical
cord.

I got this information from an industrial insurance safety
officer. It applies to Scandinavia -. things might be
different elsewhere, though I would expect regulations
to be strict in the UK, which has the world's most sensible
mains plug which carries its own fuse, and can only be
inserted one way round:-)

Iain




  #22   Report Post  
Iain M Churches
 
Posts: n/a
Default


"Fabio Berutti" wrote in message
...
Back to more palatable tubes, and considering that original 211s or 845s
are hard to find or extremely expensive, my favorite tube in this league
would be the Russian GM-70. It has a dissipation of 125W, a higher mu
than the 845 and it doesn't need to be "swung" up to positive grid for
full power like a 211, ie. the driver circuit task is easier and the final
result is probably better. I played a bit with the anode curves and it
seems that a B+ of about 1000 - 1100V together with an anode load of 10K
gives the maximum output power in SE class A, about 45W!
Or put a pair of them in PP to blast the roof...


This has really got me interested in HV tubes:-)
I have just been taking a look at some graphs for the 811, 812, 813, 845,
300B, 211. Alll of these have impressive linearity - much better than the
EL34, 6L6, KT88 etc that I have been accustomed to using.

However, the high voltage B+ puts me off. 500V for me is something
of a psychological barrier. Maybe I will try 2A3 at a humble 275V

Happy to see a real RAT thread

Yes! The sun is shining again on RAT:-)

Iain


  #23   Report Post  
tony sayer
 
Posts: n/a
Default

In article et, robert
casey writes



One needs a special respect for working with
1,000v+ anode voltages.


Then there are tubes like the 6BK4, intended as color
TV set very high voltage voltage regulators. 25KV. It's
a triode with a mu of 2000. Heard some people
use them in audio amps. Electrostatic speaker drivers?


Yes they used a shunt regulator in the old Philips valve K9 ? chassis
and that was in a box of its own, not so much as the high voltage but it
was an X-ray generator!....
--
Tony Sayer

  #24   Report Post  
Dave Plowman (News)
 
Posts: n/a
Default

In article ,
tony sayer wrote:
Yes they used a shunt regulator in the old Philips valve K9 ? chassis
and that was in a box of its own, not so much as the high voltage but it
was an X-ray generator!....


IIRC, G6. Excellent TV. But an interesting valves via SS comparison - it
needed both output stages total valve replacement about every two years.

--
*If at first you don't succeed, then skydiving definitely isn't for you *

Dave Plowman London SW
To e-mail, change noise into sound.
  #25   Report Post  
Patrick Turner
 
Posts: n/a
Default



Fabio Berutti wrote:

If You want a tube for "real men", see this one:

http://info.uibk.ac.at/c/c7/c704/mus...es/rs329g.html

Some are still available in Germany...

Back to more palatable tubes, and considering that original 211s or 845s are
hard to find or extremely expensive, my favorite tube in this league would
be the Russian GM-70. It has a dissipation of 125W, a higher mu than the
845 and it doesn't need to be "swung" up to positive grid for full power
like a 211, ie. the driver circuit task is easier and the final result is
probably better. I played a bit with the anode curves and it seems that a
B+ of about 1000 - 1100V together with an anode load of 10K gives the
maximum output power in SE class A, about 45W!
Or put a pair of them in PP to blast the roof...


PPL using GM70 here have had great results.

I have a design worked out and tried by one guy if anyone is interested.

Patrick Turner.



Happy to see a real RAT thread

Ciao

Fabio

"Andre Jute" ha scritto nel messaggio
...
rec.audio.tubes

Kilovolt transmitting tubes



Let's make a new thread here.



Chris Hornbeck wrote:



I'm a big fan of 845's; they solve a lot of speaker problems,


which are much more intractible. 211's have even better curves,


and three in parallel make 50 watts without grid current,


and into an almost-practical 5K ohm load.




Back in the 60s, when I was a student, I travelled across the States on
one
of those go anywhere one way Greyhound tickets that then cost 99 bucks.
(Somebody
said a couple of years ago that they are still only 199 bucks.
Extraordinary
value.) I spent months on the buses, meeting people. In the first week I
won
a Sony radio in a game of dice with some black men who said they were
union
organizers. When I observed that they gambled recklessly, one of them
said,
"Man, this is Charleston and the white boy thinks black union men gamble
recklessly!"
On the Sony, when there was no one to talk to, I tuned in to the smoky AM
jazz
stations that then abounded. They played real jazz, with harmony and
melody
and invention; the self-indulgent **** you hear today says absolutely
nothing
to me except that the socalled artist is committing onanism in public when
I would much prefer it to be hara kiri. Later I heard those stations used
845s in their transmitters. So when the opportunity arose, I built some
845s.
I have never ceased to love their sound.



The 211 I like much less. To me its only advantage is an easier drive
requirement,
which becomes irrelevant once you decide on a triode power tube with a
good
bit of current on it as your driver. I typically expect Americans to like
211
sound.



Tubes sonically somewhere in between are the Svetlana 572-3 and -10, with
the
-30 not quite so refined.



My Type 199 Millennium End amp is a Svetlana 572-xx switchable SE, PSE amp
of up to 75W (theoretically more but I've never bothered, in fact I mostly
use it set up for the 25W region). The KISS Amp design that I am waiting
to
resume describing is a version of the booster amp driving the Millennium.
That's
right, I use a WE300B as a pre-amp for a bigger amp.



You say "an almost-practical 5K ohm load". If you merely mean availability
of transformers, it is perfectly practical. The transformers designed for
my
T199 by Menno van der Veen are catalogued by Amplimo and Plitron. The
output
is rated of 90W, 190mA (design centre, 380mA in all), primary 5K014, and
has
secondary links 2, 4 and 8ohm to permit use of one or two SV-572-3 or -10,
or two 845, or the three parallel 211 you posit, i.e. 2K5 or 5K. The power
supply after rectifying gives a kilovolt at 200mA, 950V at 400mA, and also
has separate windings for the drivers, input tubes, bias, filaments. I use
the prototypes Menno tested for the formal description. The numbers of the
prototypes, which should permit you to find them in the Plitron and
Amplimo
catalogues, are output VDV-JUTE-HQ5090 and power supply 6632-XO. Both
firms
wind both transformers. Amplimo is in The Netherlands, Plitron in Canada.
Sit
down before you read the prices and the shipping weights. These are
monsters
probably on the very edge of feasibility for amateurs (though not by the
standards
of the more experienced radio hams).



You wouldn't happen to have a pair of 212-E for sale or trade, would you,
my
dear fellow? I have just the transformers for them already... One of the
design
specs I gave Menno was my dream of 212-E, so he returned ultra-useful
experimenter's
trannies.



Coming back for a moment to your 3x 211. At a 1000V on the plate, a 211
has
a plate resistance of around 3800 ohm. Three in parallel would show Rp a
bit
under 1300R. My experience is that you want a higher multiple of Rp for RL
on 211 than on 845, or, put more positively, 845 are more tolerant while
211
repay higher multiples. (That is why Kondo went to such extraordinary
lengths
with the output for the Ongaku, claimed to be 20K but reputedly at least
16K.)
Four times a bit under 1300R is 5K1 so you will do the job handsomely with
these trannies. On the other hand, with so much current capability in the
OPT,
you can run the 211 high and hot, somewhere over 60mA, and gain some more
silence
from that.



HTH.



Andre Jute



PS. The rest of you reckless little *******s, don't start building
kilovolt
amps before you have built several EL34 or 300B amps and run them for a
couple
of years without mishap. It's not just a different ballgame, it is on a
different
level altogether. Think permanent state of death (a morbid joke I'm
borrowing
from the novelist John Gardner) and ask yourself if you really want to
take
a fulltime holiday there. The most common UL rating for tube amp wire,
1015,
is happy with 300B voltages but not suitable for kilovolt amps; the same
applies
to caps which need bypasses if stacked, and resistors have to be specially
rated. *Everything* you use in a kilovolt amp has to be inspected with a
jaundiced
eye, and you can't even measure it with the sort of meter you until now
thought
expensive or, very probably, the scope on your workbench; the reduction
probe
you bought for 80 bucks is most probably illegal and dangerous for such
elevated
voltages. (I don't just mean the digital or silicon electronics stuff
rated
30 or 50V; a lot of common good quality high tension gear is rated 600V
max.
Always check the fuse rating inside the meter.) Just for the record, by
kilovolt
amps I mean a kilovolt and over, because the 845/211 class is rated for
1250
volts, and some other tubes we discussed or may still discuss much higher
still.





  #26   Report Post  
tony sayer
 
Posts: n/a
Default

In article , Dave Plowman (News)
writes
In article ,
tony sayer wrote:
Yes they used a shunt regulator in the old Philips valve K9 ? chassis
and that was in a box of its own, not so much as the high voltage but it
was an X-ray generator!....


IIRC, G6. Excellent TV. But an interesting valves via SS comparison - it
needed both output stages total valve replacement about every two years.


Yes the old G6 had it, but there was another one that was make in Sweden
that also had excellent sound as well, K7 or something like that?....
--
Tony Sayer

  #27   Report Post  
Patrick Turner
 
Posts: n/a
Default



Choky wrote:

"Andre Jute" wrote in message
...

you arrogant ****head;

my job ( amongst others) in local radio station is to maintenance tube FM
transmitter with 1,5KW output,and working voltage in range of 2KV.
and that's Lilliput type of facility in this sort of business.
betcha you never walked through transmitter?
imagine that sort of energy,and imagine that sort of brain muscles needed to
make that gadgets.
pity,mebbe your arrogance will be smaller .........

man with brain and with balls can do that without polluting newsgroups.
in any case-man with real job and proper attitude to life will never spill
**** in NG ,like you do all the time.

"c'mon-make my day".


Choky, you have a sore head, was it the plum brandy?

In Russia, they have power tubes so big people
can remove a panel and walk around inside to
replace a cathode.

In the bad ol days they'd give the job to a dissident, and send him in
with a spanner.
Then the secret police would spring the door shut, evac the tube, apply
50,000v, and transmit the dissident.

Their chief was heard to announce,
"That'll teach that pirate radio operator a lesson
after saying rotten things on air about Stalin"

Shostakovitches 9th Symphony makes one live in hope
when feeing down....

Patrick Turner.


--
--
.................................................. .......................
Choky
Prodanovic Aleksandar
YU

"don't use force, "don't use force,
use a larger hammer" use a larger tube
- Choky and IST"
- ZM
.................................................. ..........................


  #28   Report Post  
Arny Krueger
 
Posts: n/a
Default

"Andre Jute" wrote in message


Just for the record,
by kilovolt amps I mean a kilovolt and over, because the 845/211
class is rated for 1250
volts, and some other tubes we discussed or may still discuss much
higher still.


For me, life gets just barely interesting when you start talking about tubes
like the 4CX1000. Real men play with the mid-sized stuff like push-pull
pairs of 4CX5000. The last piece of tubed equipment I worked on had a
4CX3000, and about 400 other tubes. The real tubes in that box were
magnetically-focussed klystrons whose part numbers were classified.


  #29   Report Post  
Dave Plowman (News)
 
Posts: n/a
Default

In article ,
tony sayer wrote:
Yes the old G6 had it, but there was another one that was make in Sweden
that also had excellent sound as well, K7 or something like that?....


Heh heh - the G6 certainly had appalling sound - despite being single
ended valve. As soon as mine was out of warranty, I fitted a buffer amp
and rep coil (live chassis) to feed it to the Hi-Fi. Very unusual in those
days. We also had to do a few mods to get the vision buzz on sound sorted.

--
*I must always remember that I'm unique, just like everyone else. *

Dave Plowman London SW
To e-mail, change noise into sound.
  #30   Report Post  
Doug Schultz
 
Posts: n/a
Default


"Iain M Churches" wrote in message
...

"Fabio Berutti" wrote in message
...
Back to more palatable tubes, and considering that original 211s or 845s
are hard to find or extremely expensive, my favorite tube in this league
would be the Russian GM-70. It has a dissipation of 125W, a higher mu
than the 845 and it doesn't need to be "swung" up to positive grid for
full power like a 211, ie. the driver circuit task is easier and the
final result is probably better. I played a bit with the anode curves
and it seems that a B+ of about 1000 - 1100V together with an anode load
of 10K gives the maximum output power in SE class A, about 45W!
Or put a pair of them in PP to blast the roof...


This has really got me interested in HV tubes:-)
I have just been taking a look at some graphs for the 811, 812, 813, 845,
300B, 211. Alll of these have impressive linearity - much better than
the
EL34, 6L6, KT88 etc that I have been accustomed to using.

However, the high voltage B+ puts me off. 500V for me is something
of a psychological barrier. Maybe I will try 2A3 at a humble 275V



couldnt you do a balanced supply?
+500volts and -500Volts?
wouldnt that solve alot of the problems associated with the HV requirements
of these tubes??

Doug




  #31   Report Post  
Chris Hornbeck
 
Posts: n/a
Default

On Wed, 16 Mar 2005 09:10:44 -0500, "Arny Krueger"
wrote:

For me, life gets just barely interesting when you start talking about tubes
like the 4CX1000. Real men play with the mid-sized stuff like push-pull
pairs of 4CX5000. The last piece of tubed equipment I worked on had a
4CX3000, and about 400 other tubes. The real tubes in that box were
magnetically-focussed klystrons whose part numbers were classified.


My Army time included push-pull 250 watters from the forced-air
tetrode family, but never any of the really big guys. VHF stuff,
already obsolete in 1970. PCM though!

You raise an interesting question: has anyone ever played with
any big tetrodes with the G2 floating? I'd expect a high mu,
but there might be usable exceptions.

Thanks,

Chris Hornbeck
"That's where my forebears came from. Three of them
anyway. Who's been sleeping in my porridge?" -F&S
  #32   Report Post  
hwh
 
Posts: n/a
Default


"tony sayer" schreef in bericht
...
In article et, robert
casey writes



One needs a special respect for working with
1,000v+ anode voltages.


Then there are tubes like the 6BK4, intended as color
TV set very high voltage voltage regulators. 25KV. It's
a triode with a mu of 2000. Heard some people
use them in audio amps. Electrostatic speaker drivers?


Yes they used a shunt regulator in the old Philips valve K9 ? chassis
and that was in a box of its own, not so much as the high voltage but it
was an X-ray generator!....


PL509 tubes in the K8. Excellent Am radio finals!

gr, hwh


  #33   Report Post  
Steve Rush
 
Posts: n/a
Default

On Tue, 15 Mar 2005 21:52:45 +0000, robert casey wrote:



One needs a special respect for working with
1,000v+ anode voltages.

Its a wonder more ppl have not been killed....

Another thing, it would be mandatory that the tubes
be fully enclosed in a cage, and that cage and the
bottom lid of the amp have interlocks to disable
the power supply if opened. No pretty wood boxes
with bare tubes on top. You can chrome or gold plate
the cage if you want to make it look pretty....


_Two_ sets of interlock switches. One to kill the power supply
and one to ground the B+ lead in case a bleeder resistor opens and leaves
the filter capacitors charged. I once shut down a 20KW transmitter for
preventive maintenance and heard what sounded like a pistol shot as I
opened the door to the power supply cabinet.
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