>
>From: Peter Chadwick <Peter_Chadwick@mitel.com>
>Subject: RE: [AMPS] Amp using 833A
>>
>> Rich says:
>>
>> >Medium Mu triodes draw little anode current unless the grid is driven way
>> > positive- and that means distortion.
>>
>>
>> This is not necessarily so. Class AB2 or Class B2 operation with grid
>> current in grounded cathode requies a well regulated bias supply, and a
>> well regulated drive, but it does NOT automatically mean high distortion.
>> Pappenfus in fact says that AB2 can result in lower IMD than AB1.
>
>I think this goes back to arguments in the past Peter, where Rich
>felt that:
>
>Any positive grid to cathode potential = unacceptable distortion
>
Not an example of good reading skills. // I said that for grid-driven
config., grid current leads to downtown Distortionville. For cathode
driven, grid current is normal. The difference is RF-NFB.
>That equation isn't true in many if not most cases.
That equation is Mr. Rauch's invention. Tom scores slam dunks against
revised quotes.
>The worse thing
>about the 833 will be stability and the fact that drive power in GG
>would be too high.
>If it provides acceptable distortion in AM BC
>service as a class B or ABx modulator, it is likely to provide
>acceptable distortion performance as a linear amplifier if other
>issues can be resolved.
>
The problem with medium Mu tubes in grid-driven linear service is that
they can not draw enough peak anode current
>
later, Tom.
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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