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Re: [TenTec] THANK YOU

Subject: Re: [TenTec] THANK YOU
From: Jim Brown <k9yc@audiosystemsgroup.com>
Reply-to: k9yc@arrl.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 02 Feb 2012 09:50:45 -0800
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
On 2/2/2012 8:00 AM, k3miy@csonline.net wrote:
> I, and others, know of properly terminating
> an audio input to avoid ground loops and potential RFI. Usually this is
> done by the input device(mike, amp etc). In a test situation,  a termination
> resistor that doesn't draw any current does the same thing.

A termination resistor will draw as much current as Ohm's Law dictates 
as a result of the  voltage across it. Actually, audio interconnects are 
NOT designed to be terminated by resistance, and have not been for at 
least 40 years. That USED TO BE the practice, in the days of vacuum 
tubes, but since at least the 70s, audio output stages are designed to 
NOT see a load resistance or impedance. In fact, output stages want to 
see load resistance equal to at least 5 times their output impedance, 
and a higher impedance is better. The only folks who haven't gotten the 
word are those working in ham radio -- the broadcasters figured this out 
in the 70s.

73, Jim K9YC
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