Behold, George H. Fathauer & Assoc.LLC signalled from keyed 4-1000A
filament:

I have several good used RCA type 813 tubes. I'll send 1 or 2 tubes UPS
for $10 to cover packing and shipping. George

How much to ship to Vancouver, Canada?

:-)

--
Gregg
*It's probably useful, even if it can't be SPICE'd*
http://geek.scorpiorising.ca