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Re: [Amps] Effects of load Z mismatch?

To: garyschafer@comcast.net
Subject: Re: [Amps] Effects of load Z mismatch?
From: jkearman@att.net (Jim Kearman)
Date: Mon, 09 Jan 2006 20:56:47 +0000
List-post: <mailto:amps@contesting.com>
 
> Loading an amplifier heavier than where maximum output occurs helps to 
> keep the operating region in the more linear portion of the load line. 
> In other words heavier loading helps keep the operation down below the 
> upper curve of the load line where flat topping starts to occur, but at 
> the expense of some efficiency.

Thanks. If I understand correctly, loading more heavily presents a lower 
impedance to the anode(s), and also incidentally reduces network Q. As a CW op, 
my main concern is efficiency and minimizing harmonics. It was difficult for me 
to feel confident that I was correctly calculating the required load impedance 
for my 4CX800As. Now I see that by making the load C large enough, I'll have 
the flexibility to match a wide range of plate Zs while maintaining adequate 
network Q. Having enough loading C only becomes a problem on 80 and 160, but 
this amp will be used only on 160-80-40, so getting those numbers right was 
critical.

73,

Jim, KR1S
http://kr1s.kearman.com/


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