hint: If you look at the VAS voltage instead of the power output you find the inverse of the cross-over distortion, magnified by the neg feedback. Here you can observe the effect of biasing through a magnifying glass.
Bingo, Bucks. This is the way.
Note that the goal of the class A stage is not, as often said, to fill the non-conduction area of the class C transistors.
In fact the class C stage provides the heavy current that the class stage can't. All this is under the control of a bridge and feedback, the expected result being that amplifier has a constant output impedance during a full cycle.
In fact the class C stage provides the heavy current that the class stage can't. All this is under the control of a bridge and feedback, the expected result being that amplifier has a constant output impedance during a full cycle.
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Hi
The Nak 620 output stage is simply a diamond where each of the four positions is a Darlington, although everything is discreet. This provides a single node input.
Personally, I disagree with Self's definition of "class-B" as there is a small overlap of conduction nd each half of the output stage is therefore 'n' for more than 180-degrees of the signal.
The Nak 620 output stage is simply a diamond where each of the four positions is a Darlington, although everything is discreet. This provides a single node input.
Personally, I disagree with Self's definition of "class-B" as there is a small overlap of conduction nd each half of the output stage is therefore 'n' for more than 180-degrees of the signal.
Hi Stanislav1957
If you are referring to post-35, the upper case looks like class-B but the lower case does not. It is hard to tell exactly because at least for me the images do not expand very much and are hard to read. Your later post says the output devices idle at 2mA. Is that for the upper circuit?
Regarding the OP's Nak 620 being "current drive": I think this refers to the fact that like all diamond stages the output devices are turned 'on' by current sources. The default would be for the outputs to be turned on to the max and melt down the supply The only thing keeping this from happening is the input half of the diamond, provided their net BE voltage plus any RE voltage is less than what the output devices need to draw a lot of current.
If you are referring to post-35, the upper case looks like class-B but the lower case does not. It is hard to tell exactly because at least for me the images do not expand very much and are hard to read. Your later post says the output devices idle at 2mA. Is that for the upper circuit?
Regarding the OP's Nak 620 being "current drive": I think this refers to the fact that like all diamond stages the output devices are turned 'on' by current sources. The default would be for the outputs to be turned on to the max and melt down the supply
The only thing keeping this from happening is the input half of the diamond, provided their net BE voltage plus any RE voltage is less than what the output devices need to draw a lot of current.This is the same amplifier with a quiescent current of the output transistors of 1-3mA .Only the C11 capacitor circuit was turned off and that was it. My question was not on the mode, but on the amplifier circuit.
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