[Amps] 4-1000 Bias

[Robrk]

Why is there "no signal" grid current?

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On Mar 1, 2011, at 12:38, "Wayne Rogers" <n1wr at chesapeake.net> wrote:

> I have a 4-1000 g-g homebrew amp.  It was designed 4000 volts on the plate. 
> My new supply is 5500 volts under load.
> 
> With the grid at ground potential and at 4000 volts on the plate the no 
> signal grid current is 40 mA. and the plate current is 170 mA, which seems 
> right.
> 
> At 5500 volts on the plate and the grid at ground potential Ig is 80 mA. and 
> Ip is 300 mA. which seems a bit high. My plan is to add bias to the grid. 
> How do I determine what the correct operating point is for grounded grid? 
> At 300 mA. I'm dissipating .3 X 5500 = 1650 watts which is way over the 
> tubes rating.
> 
> Thanks,  Wayne N1WR 
> 
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