[AMRadio] 813 filament voltage

[SBJohnston at aol.com]

I'm resurrecting a very nicely-built homebrew grounded-grid 813 amp.  I 
noticed that the filament voltage at the pins is 8.5 vac.  Nominal on the 813 is 10 
vac as I recall.  Is the 8.5 OK or will emission suffer?   I guess I could 
also be into an RMS versus average metering issue... hmmm.

I also could use a known-good 813 for testing... anyone have one for sale?

Thanks...

Steve WD8DAS