> To: David VK3EW <vk3ew@rint.com.au>
> From: philk5pc@connect.net (Phil Clements)
> Cc: amps@contesting.com
> Subject: Re: [AMPS] SB-220
To: <amps@contesting.com>
> Date: Wed, 18 Jun 97 16:52:09 +0000
> Why screw up a near-perfect circuit? The filament transformer is specially
> designed to be self-limiting on inrush current. The 3-500Z has instant-heat
> filaments. You are not hurting a thing when you turn it on and off. You are
> eliminating a major source of failure...HEAT.
Hi Phil,
As I understand what you are saying, you seem to be indicating
turning the filament off and on does not decrease tube life.
If so, I disagree with that.
A very common reason filaments fail is because of accumulated damage
from constant exposure to mechanical stress from large temperature
changes. This damage is accumulated over a period of many temperature
cycles.
If I intended to drop the amp in and out of line during one
operating session, I'd simply open the relay line while leaving the
filament on, avoiding needless wear and tear on the filament.
73, Tom W8JI
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