"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

"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

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.

"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

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.

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

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

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?

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

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.