On Apr 19, 12:30*pm, AndyS wrote:
On Apr 18, 9:22 pm, JIMMIE wrote:

I have an HF amp that uses a single 811A in grounded grid. The power
transformer smoked. The transformer was from an old TV set I think it
was rated at 540VAC on the sec and I ran it into a voltage doubler for
about 1300 VDC *. Any info on something I could use as a replacement
would be appreciated.

Jimmie

Andy comments:

* You might investigate using a high voltage transformer from an old
microwave oven...... *If the secondary voltage turns out to be too
great,
their construction makes it fairly easy to remove some turns...

* *I haven't tried this, .... just something to consider..

* * * * * * * * * * Andy W4OAH

Was also going to suggest an ex-microwave oven transf. Have a number
of scrapped microwave transformers.
Here (Canada) I've checked the ratio between the 115 volt input
winding and the secondary and it's close to 1:20.
In a 230 volt country I guess it would be around 1:10???
The secondary is therefore around 2200 volts RMS. That's toot high;
but if that was half wave rectified through a single diode with a
choke input filtering circuit etc. and capacitors with sufficient
voltage rating you might end up with a suitable 1300 volts or so?
Alternatively various methods of reducing the input voltage from 115
or 230 volts could be experimented with. Voltage bucking (opposing),
removing turns from the secondary or maybe even some sort of voltage
dropping circuit in the input winding?
Of course the 811A needs heater voltage from somewhere as well!
Just thinking out loud!