Need 800V reg'd .2A to .3A for Sg2 of Russian tetrode tube.
Anyone have ideas maybe tube regulator.
HV Zeners do not appear to stand up--failures.
tnx AL

al goss wrote:
Need 800V reg'd .2A to .3A for Sg2 of Russian tetrode tube.
Anyone have ideas maybe tube regulator.
HV Zeners do not appear to stand up--failures.
tnx AL



I might recommend the 6336B. It will require a high-temp (read: ceramic)
socket and generate a tremendous amount of heat. The regimen for
changing a 6336B is to use asbestos gloves. The tube has a 6.3v filament
which is convenient. Somewhere I have an appropriate schematic.

K3HVG wrote:
al goss wrote:
Need 800V reg'd .2A to .3A for Sg2 of Russian tetrode tube.
Anyone have ideas maybe tube regulator.
HV Zeners do not appear to stand up--failures.
tnx AL


I might recommend the 6336B. It will require a high-temp (read: ceramic)
socket and generate a tremendous amount of heat. The regimen for
changing a 6336B is to use asbestos gloves. The tube has a 6.3v filament
which is convenient. Somewhere I have an appropriate schematic.

Just because the load is a tube doesn't mean that one should use a tube
linear regulator to provide the power.

A switcher would be a much better power source.

-Chuck

al goss wrote:
Need 800V reg'd .2A to .3A for Sg2 of Russian tetrode tube.
Anyone have ideas maybe tube regulator.
HV Zeners do not appear to stand up--failures.

The problem is the starting surge on the zeners. Set the zeners up
with a very high value resistor in series with them, so that you only
have a tiny trickle of current generated with the shunt regulator.

THEN, apply the regulated voltage from the shunt regulator to the base
of a big NPN pass transistor. You MAY need to use a darlington to get
enough gain to get it to regulate properly, but maybe not.

In theory, the transistor only needs to be rated for the voltage drop
across it, so you can use an MJE18006 transistor (1KV breakdown) without
any problem. In practice I like to have a little more safety margin.

The series regulator is a LOT more efficient than a shunt regulator.

If you do it with a tube in place of the transistor, consider the 6HV5,
maybe?
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

al goss wrote:
Need 800V reg'd .2A to .3A for Sg2 of Russian tetrode tube.
Anyone have ideas maybe tube regulator.
HV Zeners do not appear to stand up--failures.
tnx AL


Hi,

Does that tetrode have negative screen current at some
loading/drive conditions? If so, that will complicate
the screen regulator design.

73,
Ed Knobloch