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[AMPS] linear amps

To: <amps@contesting.com>
Subject: [AMPS] linear amps
From: W8JI@contesting.com (Tom Rauch)
Date: Tue, 30 Jan 2001 11:52:55 -0500

> 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? Did you still use the 
same inductance Heath used?

Did you check the neutralization?

With hundreds or thousands of Warriors working fine, including one 
I own, it seems foolish to make drastic changes rather than just 
correcting the problem.




73, Tom W8JI
w8ji@contesting.com

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