>
>> If "tinks" in a vacuum can be heard (ie. de-wiskering a vacuum cap), then
>> big bangs in a vacuum should also be heard.
>>
>> Phil
>
>Actually
? (key word)
> all the banging and tinking you hear from the tube are
>conducted through the elements to the envelope and then to the air.
>
? [chortle]
>That isn't the bulk of the noise you hear. The bulk of the noise is
>caused by other things in the PA moving and arcing when the tube
>faults.
>
? other things?
>Amplifiers get very quiet during a fault if you use enough series R in
>the supply, and series R of the correct type, to limit fault currents.
>
>My big amplifier, with an 8000 volt supply and 40 mFd of
>capacitance, barely makes a sound when a tube occasionally
>faults. That's because it has 25 ohms of six inch long globar style
>resistor and a dump circuit. The amp just tics, shuts off, and resets.
>
>The most common cause of a fault is either outgassing or a
>whisker (barnacle) in the tube after an extended period of non-use.
>
>If the tube arcs from a parasitic, it will arc from fundamental RF just
>as well.
>
? Oscar Meyer.
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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