Comparing company X’s class A amp with company B’s class AB amp may not mean much. I bet even there are many class D amps that sound better than class A amps at the same price point.
I cannot think of apple to apple comparison, but how about these?
- Between a class A amp with another class AB amp at the same price point: if you find a class AB amp sounds better than or equal to any class A amp at the same price, why would you go for class A?
- Between class A setting and class AB setting from the same amp: if class A setting does not sound any better than class AB setting, what’s the point for the extra cost of class A setting?
For my Plinius SA102, I cannot hear any difference between class A and AB settings in most music. Only when the music is very demanding (more bass and dynamics) I can tell some difference, but still the difference is not day and night difference.