> Instead it is in fairly Deep Class B in CW with a much lower
> idle current which also works well in AM.
Class B is defined as a conduction angle of 180 degrees exactly -
therefor one can not be "fairly deep Class B". It might be deep into
Class AB2 - i.e., well beyond the point at which the tube starts to
draw grid current - but class B is a specific operating point not a
range like AB1, AB2 or C.
Class A = conduction angle 360 degrees
Class AB1 = conduction angle between 180 and 360, no grid current
Class AB2 = conduction angle between 180 and 360, with grid current
Class B = conduction angle 180 degrees
Class C = conduction angle less than 180 degrees
73,
... Joe, W4TV
On 1/13/2016 12:41 PM, Carl wrote:
The FCC did it!
Originally the rule was 1000W DC input for any mode. Then it changed to
2000W PEP for SSB only so the plate transformer was tapped and a switch
added,
Some of those older amps have a pretty wimpy transformer and not suited
for heavy duty CW use in the SSB position.
The Ameritrons with that switch change the bias but it never goes into
Class C. Instead it is in fairly Deep Class B in CW with a much lower
idle current which also works well in AM. The HV doesnt change.
Carl
KM1H
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