Don´t try that with the 4CX250B, it will loose its grid as soon it is driven
73
Peter
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Hardy Landskov
Sent: Montag, 20. Juli 2009 23:14
To: Paul Kraemer; donroden@hiwaay.net; amps@contesting.com
Subject: Re: [Amps] Grounded Grid(Screen) 4CX250B power gain
Years ago we used to tie the screen and control grids together and ground
them in 4-1000's. It was very stable but took a lot more drive.
Hardy N7RT
----- Original Message -----
From: "Paul Kraemer" <elespe@lisco.com>
To: <donroden@hiwaay.net>; <amps@contesting.com>
Sent: Monday, July 20, 2009 12:10 PM
Subject: Re: [Amps] Grounded Grid(Screen) 4CX250B power gain
> Anyone have a comment about the theory behind connecting the grid through
> a
> resistor to the cathode in a "grounded grid" amp because grounded grid it
> isn't. Does the screen being grounded act as the grid in a low mu triode
> in
> that configuration? The article mentioned earlier says it works. I am
> curious how well it works and what the gain is.
> Paul K0UYA
> ----- Original Message -----
> From: <donroden@hiwaay.net>
> To: <amps@contesting.com>
> Sent: Sunday, July 19, 2009 9:19 PM
> Subject: Re: [Amps] Grounded Grid(Screen) 4CX250B power gain
>
>
>>I had a 30L-1 "lookalike" that used four 250Bs in GG. The control
>> grids were grounded through resistors and the screen terminals on the
>> sockets were bent over and soldered to the metal socket. Don't know
>> about tying the cathode to the control grid.... ( ????? )
>>
>> Don WA4NPL
>>
>>
>> Quoting Hsu <hsu4qro@gmail.com>:
>>
>>> Hi, George,
>>> I just modyfy the Henry TEMPO 2001
>>> convert the 3CX400A7 to 4CX250B in GG configation, tied the
>>> cathode and G1(serial a 100ohm resistor) together.
>>> I'll test it today.
>>> 73!Hsu
>>> ----- Original Message -----
>>> From: <gdaught6@stanford.edu>
>>> To: "Hsu" <hsu4qro@gmail.com>
>>> Sent: Monday, July 20, 2009 5:26 AM
>>> Subject: Re: [Amps] Grounded Grid(Screen) 4CX250B power gain
>>>
>>>
>>>>> Nin hao George,
>>>>> Have your built the amplifier like this GG configation?
>>>>
>>>> No, I haven't built one in GG. I always use "passive grid
>>>> configuration", with a
>>>> resistor driven by the exciter, and the grid just attached to the
>>>> top of the resistor.
>>>>
>>>> 73,
>>>>
>>>> George T Daughters, K6GT
>>>> CU in the California QSO Party (CQP)
>>>> October 3-4, 2009
>>>>
>>>>
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>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
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