Sit on a dry wooden chair, with your feet off the ground, and one hand
in your pocket.

Good luck,
Old Chief Lynn, W7LTQ



CONSIDER:

Using a bench top isolation transformer.

-Or-

http://www.mif.pg.gda.pl/homepages/f.../1/117N7GT.pdf

I can add up about 15 watts of plate dissipation and filament wattage.
Perhaps an isolation transformer may be in line here. Use two similar wall
warts of about 30 to 40 watts min. Same voltage secondary.

Connect the AC section of the secondary (before the rectifier and capacitor
with in a DC wall wart) together and you have an isolation transformer for
that single tube project. If you choose 6 or 12 volt secondary you also
have a future filament supply for other projects.

You may have to establish a ground for this circuit when using an isolation
transformer.

A bit of safety does not hurt,

Paul P.