[AMPS] Re: Parasitics

[Larry Molitor]

At 16:40 5/18/98 +0000, Tom Rauch wrote:

>I assume you mean the time varying resistance of the anode as 
>modified by stray reactances..............

Tom, thanks for your post. I found it interesting, informative, even
thought provoking.

I hope you don't take this comment the wrong way, as I really am serious
this time, and I don't want to start a pissing contest. I really have a
problem with the term "unconditionally stable". To state a design is
"unconditionally stable" is to assume a position of omnipotance. And while
you certainly are a talented design engineer, I can't quite credit you with
omnipotance. If you said " The amp is completely stable at VHF under all
conditions that I am aware of", I would accept that without question.

Having said that, let me ask you a tech question. 


>There are other methods ( such as moving anode and grid resonances 
>apart, .........

How do you measure grid circuit resonances? It's easy in the anode circuit
(big parts, lotsa lead), but have never had much success with the grid. I'm
sure it's because I try to build them all like they were GHz range amps,
and there is virtually no lead length to couple my GDO to. The technique
must work, as I have built a couple HF amps that were *completely stable
under all conditions that I was aware of*. However, it bothers me that I
just *shotgunned* it and don't really know where the resonances are. How
would you do it?

73,

Lary - W7IUV
w7iuv@axtek.com
www.axtek.com/w7iuv/

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