>
>Tom says:
>
>>I think this goes back to arguments in the past Peter, where Rich
>>felt that:
>>
>>Any positive grid to cathode potential = unacceptable distortion
>>
not in g-g.
>>That equation isn't true in many if not most cases. The worse thing
>>about the 833 will be stability and the fact that drive power in GG
>>would be too high.
>
>This is all very true. However, there is an anomaly in the argument in
>that in
>GG AB2, the grid does go positive with respect to the cathode. The
>reliance is
>on negative feedback to keep distortion down.
good point
>Further, because the tube is
>either zero bias or can be biased with a zener, the bias supply can be made
>pretty stiff. Absolutely no reason why a stiff bias supply can't be used in
>grounded cathode, or for that matter some NFB too.
A cathode RF-NFB resistor tends to reduce cathode-screen potential on
voice peaks. // Of what use is a regulated bias supply if no grid bias
current flows?
>
>The drive power requirement is inherent in the fact that tubes for power
>oscillator use, especially where the load is very variable as in RF
>heating, are
>
>for best performance, low mu devices.
>
>But there are operation modes other than GG!
>
grounded cathode is the only other game in town.
>
cheers, Peter
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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