Kirkus - Yes, saturation can appear without any gain in the circuit but it has nothing to do with the issue we're discussing.
High slew rate input signals come back to summing junction thru negative feedback delayed because of signal path delays. For a moment amplifier has no feedback and overshoot appears at the output (or earlier dependent on design). This will happen to any amplifier if slew rate is not properly limited at the input.
Amount of this overshoot is a function of amps open loop gain and in really bad case will take output stage to momentary saturation.
Let forget what is causing it, I agree, and look what to do to fix it. Class AB amp exhibits higher order of mostly odd harmonics at very low signal levels while THD and IMD is measured at substantially higher levels and doesn't show it. In order to lower it - either components have to be very linear or feedback has to be deeper. Careful selection of transistors and better circuit will help to a degree but will never eliminate big "kink". Local feedback will help as well but most of the linearizing will be done in the global NFB (global vs. local is a separate discussion). Bandwidth has to be limited at the input to bandwidth of the amp without the feedback (open loop). That's all. It is tradoff between low level THD and bandwidth on one side and TIM on the other.
High slew rate input signals come back to summing junction thru negative feedback delayed because of signal path delays. For a moment amplifier has no feedback and overshoot appears at the output (or earlier dependent on design). This will happen to any amplifier if slew rate is not properly limited at the input.
Amount of this overshoot is a function of amps open loop gain and in really bad case will take output stage to momentary saturation.
Let forget what is causing it, I agree, and look what to do to fix it. Class AB amp exhibits higher order of mostly odd harmonics at very low signal levels while THD and IMD is measured at substantially higher levels and doesn't show it. In order to lower it - either components have to be very linear or feedback has to be deeper. Careful selection of transistors and better circuit will help to a degree but will never eliminate big "kink". Local feedback will help as well but most of the linearizing will be done in the global NFB (global vs. local is a separate discussion). Bandwidth has to be limited at the input to bandwidth of the amp without the feedback (open loop). That's all. It is tradoff between low level THD and bandwidth on one side and TIM on the other.