[Elecraft] 100 Watts or 500 Watts

[Dale Parfitt]

Hi Vic,
Dave Ishmael has a single 813 amplifeir in this month's Electric Radio. 
Please do  publish your amp for all of us to look at. I still have an 813 
and socket I have had since I was a kid- maybe it's time to build an amp for 
my Atlas 350XL.

Dale W4OP
----- Original Message ----- 
From: "Vic K2VCO" <vic at rakefet.com>
To: <elecraft at mailman.qth.net>
Sent: Wednesday, December 22, 2010 11:14 AM
Subject: Re: [Elecraft] 100 Watts or 500 Watts


>I just finished building a grid-driven amplifier using two 813 tubes. With 
>a 3 db
> attenuator at the input, it requires between 16 and 40 watts of drive on 
> 160 through 10
> meters respectively, for 800 watts output (only 700 on 10). Without the 
> attenuator, it
> would need 8 - 20 watts drive.
>
> And this is a class-C amplifier designed for CW only! If it were a class B 
> or AB linear,
> the drive requirement would be even lower.
>
> Grounded-grid is not the only way to design a tube amplifier. Although a 
> traditional
> grid-driven circuit is a little more complicated, it's one way to get more 
> gain.
>
> I am going to put some pictures and schematics on my web site soon, not 
> that I think
> anyone will want to duplicate it!
>
> On 12/22/2010 7:50 AM, Ron D'Eau Claire wrote:
>> Even the Elecraft 100 watt amps are integrated with either the K2 or K3
>> control logic so they cannot be used as a stand-alone amplifier with 
>> other
>> transmitters.
>>
>> The only reason I have ever seen from the FCC for the amplifier
>> certification and 15 dB gain limitation is to discourage the CB
>> 'bootleggers'. Certainly building a stable, clean amplifier that would 
>> take
>> even a few milliwatts to 1000+ watts is a straightforward design 
>> exercise.
>> There's no real problem with using more than one stage of gain if there 
>> was
>> no 15 dB limit on the system gain.
>>
>> Ron AC7AC
>
> -- 
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco/
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