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RE: The most common topology

"Runs class A at lower power levels"

No it does not. Class AB is nothing more than Class B with a little idle current in both devices to limit crossover distortion.

In a Class A amplifier the output devices are biased at the mid point of the most linear part of the operating curve (transfer curve) allowing linear and symeterical operation in both directions (increase and decrease of current) from the idle point with the input signal limited so that the operation stays away from the non-linear cutoff and saturation regions of the devices.

With Class AB the devices are biased at a point that is already down in the non-linear cutoff region. None of the power made by a Class AB amplifier is Class A power. There is a small amount of power produced while both devices are on and conducting but that does not make that power "Class A" power for the reasons given above.

I think there are some designs that operate in both Class A and (when needed) Class AB but that requires "sliding bias".

Tre'
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"Still Working the Problem"

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