[Amps] tube impedance, figuring tank circuit values

[Partain, Chuck]

So, when I power up my amp, I see 3910vdc on my plate. The way I have it configured, I put 330vdc on the screen grid
and -130volts on the control grid., when I bring the control grid to -69v, the tube pulls current. The voltage on the plate is
dropping to ~3600 to 3700. Is this the value I would use to figure the impedance of the tube for tank calculations?

 Initial tank settings using ~2k ohm seems to work, but i'm going to rip all that out and(try to) make this go from 160 to 15, versus
what I have now 80, 20 and 40. 

forget 10 too much C left.

thanks



Chuck Partain
SPG Compatibility Engineering
maxtor corp
333 south st
shrewsbury, ma 01545
508-770-3496