[Boatanchors] Grounded Gid Amp Bias?

[Keith Densmore]

Hi All,
I am working on refurbishing  a homebrew grounded grid amplifier. It runs 2 
x  3-500Z's. I would like to be able to cut off the tubes idle current 
during no drive condition but with HV applied.
I see the Heath SB-200 amp uses a positive bias on the filaments  to cut off 
tube current. I like this idea but here is my question. The way this set is 
wired is that the filament transformer is 10 volts not 5. The center tap of 
the filament transformer is grounded and each of the other two  legs go via 
an rf choke to one side of a 3-500 filament. The two other filament 
connections  are joined, but not grounded. Filament voltage is nearly 
identical on each tube.  My guess is that if I lifted the center tap off 
ground and fed 100 VDC to this point, the tubes will stop conducting. I 
obviously don't want to experiment so maybe someone could tell me if this 
will work, won't work, is insane????

Thanks All,
73,
Keith ve3ts