>
>Rich said:
>
>> For a tetrode, if the anode V increases, ZSAC increases. If the
>>increase was due to a rise in mains-V, -- and the mains also powers the
>>grid bias supply, the increase in ZSAC is somewhat countered by an
>>increase in -V to the grid. Thus, in this case, an unregulated grid bias
>>supply would provide a miniscule advantage.
>
>If the tetrode has any Ra (plate resistance) at all, Ia is relatively
>insensitive to Va.
Pentodes are even less sensitive.
> It is sensitive to Vg2, and my original comment was
>that if
>Vg1 and Vg2 are unstabilised so that they both float with changes in
>mains, then
>the zero signal plate current stays relatively constant. Which is pretty well
>what Rich says, if different words. Guess we have agreement on that point.
>
>Note I differentiate here between 'stabilise' and 'regulate'. Regulation
>is the
>variation in voltage of a supply with changing load: stabilisation is
>variation
>of the supply with changing input.
>
>Zeners are best fed from constant current sources - it's just not always
>possible!
>
connecting to the anode supply through a high-Z dropping R comes close
enough.
>
cheers, Peter
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
end
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