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[AMPS] linear amps

To: <amps@contesting.com>
Subject: [AMPS] linear amps
From: 2@vc.net (measures)
Date: Tue, 30 Jan 2001 09:39:35 -0800
>
>
>> I have a Heathkit  Warrior, so are you saying it is safe to remove the
>> neutralization cap? 
>
>If you do that, the amp will be like a Collins 811 amp and oscillate 
>on 21 and 28 MHz
>
>It would be my advice to leave well enough alone, and NOT take 
>misguided advice.
>
> And if so what kind of provision should be made
>> in its place?  I have a Warrior that burns up parasitic suppressers
>> and makes loud crackling sound when HV is turned on and biased by a
>> terminal being grounded during tx/rec.  I replace the parasitic
>> suppressers, checked the neutralizing gap, and replaced tubes and it
>> still does it.  Needless to say its been sitting on the bench for a
>> few months because of frustration.
>
>The oscillation, depending on the frequency, may not be at a 
>frequency where tube characteristics change greatly, up above 100 
>MHz. If that is the case the neutralization will not affect stability, 
>because the grid is effectively not grounded. That mode operates 
>the tube as a TPTG oscillator, so the filament (cathode) is not 
>involved to any large extent in the problem.   
>
>When you changed suppressors, did you use actual carbon 
>composition resistors or did you just use regular carbons? How do 
>you know the resistors are non-inductive? ..

There is no such thing.  All resistors have inductance.  The 100-ohm 
resistor we use in our parasitic suppressor retrofit kits has c. 11nH.  

end

-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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