[Amps] 4-1000 Bias

[Jan Erik Holm]

Something ain´t right. Grid should be 0 mA.
ZSAC should be around 150 mA with around 5 kV.
I ran GG 4-1000A´s for over 30 years. No
bias should be needed at all.

73 Jim SM2EKM
-----------------
On 2011-03-02 23:09, Robrk wrote:
> Why is there "no signal" grid current?
>
> Sent from my iPad
>
> 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
>>