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Re: [Amps] Supply question

To: "Sam Carpenter" <>, "Amp Reflector" <>
Subject: Re: [Amps] Supply question
From: "kingwood" <>
Date: Wed, 20 Jul 2011 13:01:03 -0500
List-post: <">>
Greetings to all,

        As I recall, EIMAC' s "Care and Feeding of Power Grid Tubes" says 
that the getter material, if any at all, is in the cathode (filament) of the 
tube, not the anode.  It is the heating of the filament, containing the 
getter material, that causes internal gas to be ionized, emulsified, and 
bonded back into the metal of the anode (plate) of the tube.  This is why an 
operator can "burn" the gas out of an EIMAC tube, but can not, in tubes like 
the Penta Labs PL-172, which has no getter material.

        With this in mind, the color of the anode (plate) of the tube has 
nothing, or very little,  to do with "getter action", but rather the thermal 
reaction of the metal in the anode to heat.  Of course they run with color, 
when ran any near their rated plate dissipation.

        Also, every tube chart I have looked at (note I did not say all) 
shows that third, and fifth, order IMD is better (less) with higher anode 
voltages.  That is why most amp manufacturers recommend that their amps be 
operated with the highest anode voltage offered when operating in SSB.

Lon W. Cottingham

1110 Golden Bear Ln.
Kingwood, TX 77339

281-795-1335 Cell 

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