[Amps] Muting 813's

[Gary Schafer]

I have an old amp with 813's in grounded grid. All grids are grounded 
directly. To cut the tubes off during standby I raise the center tap of 
the filament transformer above ground. There is a resistor to ground 
that stays during standby.
There is about 2600 volts on the plates at standby. There is a small 
amount of plate current indicated. I think around 20 ma.
I am going to raise the plate voltage to around 3000 or so.

I am assuming that the standby current I am seeing now may be plate to 
grid or plate to screen current?

Is there a more preferred way to cut those tubes off during standby?

Thanks
Gary  K4FMX