[Amps] Voodoo Magnetic Fields

[2]

>At 05:18 PM 2/12/2003 -0800, you wrote:
>...snippage...
>
>
>> >This is totally consistent with John Lyles' observation of a "small blip
>> >on the ion gauge" in pumped tubes whose pressure is being continuously
>> >monitored.
>> >
>>**  The tubes John Lyles works with have an ion pump.  3-500Zs do not.
>>Also, you have not yet explained cold gettering.   I have a 3-400Z that
>>has exhibited c. 10uA of leakage @8kV for the last 7-years.  When should
>>the gettering process be finished?
>
>I don't think this negates Ian's point. 

What evidence is there of cold gettering?  
- During the Grate Parasitics Debate with the amplifier "expert", it was 
claimed that "Big-Bangs" in g-g amplifiers were caused by a tube gas arc. 
  I argued that:
1.   In a near vacuum, the sound would not be transmitted like it 
originated in air. [vacuum cap arcs are quite quiet]
2.  I found no arc marks in any of the tubes I autopsied after a big-bang.

>Aren't ion pumps (the standard diode 
>type, anyway) essentially gettering (hard to believe that's really a word) 
>the gases?

If it Gets something, Kim, what else would you call it besides a getter?  
Ain't English phun?
>
>Also, ion pumps operate at quite a bit lower pressures than our small 
>transmitting tubes use.  I think someone noted that the glass tubes are 
>pumped down to 10^-8 Torr, while ion pumps work at around 10^-11 Torr.  Are 
>the pressures in the BIG transmitting tubes really that much lower?
>
Yes.  22kVDC is a whole nuther ballgame.

cheers, Kim

-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, 
www.vcnet.com/measures.  
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