>
>
>On Sun, 18 Oct 1998 08:05:18 -1000 "Jim Reid" <jreid@aloha.net> writes:
>
>SNIP prior to wandering
>
>
>>But I wander. The tubes in the Henry units intrigue me; they are
>>"instant on"!. My present linear mandates a 3 minute wait before
>>it will operate after powering up. What is different here? Some sort
>>of un-needed cathode warm-up or chemical emission enhancement
>>process required in 3CX800's not needed in 3CX1200D7's or the
>>3CX3000A7 triodes? Any comments about the tubes Henry is using;
>>guess they have used them for decades, or so, hi.
>
>Instant on are the tungsten filament tubes.....3CX1200, 3-500Z, 3CX3000,
>etc....actually instant-on should add a good 15-30 seconds for safety.
>In those amps you apply the RF directly to the filament.
Safety from ________? The tungsten-dicarbide emissive layer on the
filament surface is atomically bonded. As far as I know, the only known
way of breaking these bonds is to use a supply potential in excess of
20kV.
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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