Behold, Ronald scribed on tube chassis:

How about a 7812 with a Si diode in the ground leg ?

Ronald .

That works fantabulous :-)

But regulation goes to about 1% then.

Also don't forget, which most do, to place the I/O bypass caps to the
*common* pin, not ground and use, preferably, a 2.2 to 10uF tantalum
across the Si diode ;-)

7805 with 2 or 3 (depends on load) 1N400x diodes work great for 6.3V
heaters.


--
Gregg "t3h g33k"
http://geek.scorpiorising.ca
*Ratings are for transistors, tubes have guidelines*