[Amps] Small Amplifier

[Will Matney]

I have seen where some tried running the cathode driven. However they  
weren't straight G-G as they used some screen voltage and a bias. They  
don't run too hot this way in my opinion. But, they carry a lot of whollop  
when running four as grid driven with very little drive. Most amateur amps  
using this setup had an attenuator in the grid circuit to allow a  
transceiver with standard output to drive them. The first one of these I'd  
built, I can remember remarking, "Now that will walk the dogs and lead the  
pups" :) If I were to build again, I would have to use a couple of  
4CX800's though. Way less expensive and easier to fabricate.

Will



On Tue, 18 Jan 2005 01:05:52 -0800, R. Measures <r at somis.org> wrote:

> Since c. 75% of the total grid-I flows in the (2w) control-grid and c.  
> 25% of the total grid-I flows in the (12w) screen grid, the 4cx250B  
> hardly seems to be suited for g-g operation.  However, a friend tells me  
> that it has been done on SSB.
>
> On Jan 17, 2005, at 4:32 PM, carl seyersdahl wrote:
>
>> Is the 4cx250b useable in G-G?? (safely)
>>    carl / kz5ca
>> ----- Original Message -----
>> From: "Will Matney" <craxd1 at ezwv.com>
>> To: <Amps at contesting.com>
>> Sent: Friday, January 14, 2005 12:15 PM
>> Subject: Re: [Amps] Small Amplifier
>>
>>
>>> David,
>>>
>>> I think if I wanted the ability of full legal limit power, I'd run (4)
>>> 4CX250B's in parallel. I've built a few of those and they do have the
>>> muscle.
>>>
>>> Will
>>>
>>>
>>>
>>> On Fri, 14 Jan 2005 11:26:18 -0500, David C. Hallam  
>>> <dhallam at rapidsys.com>
>>> wrote:
>>>
>>>> I want to build a new small amplifier for those times when I really
>> don't
>>>> want to heat up the shack with the 5CX1500A.  I have a supply of
>> 4CX300's
>>>> and sockets as well as 4CX250's and sockets.  I plan to use two in
>>>> parallel.
>>>> Is there anything to recommend one over the other?
>>>>
>>>> David C. Hallam
>>>> KC2JD
>>>>
>>>>
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>>>
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>>
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>
> Richard L. Measures, AG6K, 805.386.3734.  www.somis.org
>
>
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