Actually, a class A amplifier won't deliver any more power to the speaker than an AB1, AB2, or a B of the same rating.
To explain it in simple terms, the tube/transistor in a class A circuit has to do all the work. It biased in the middle of its operating range where it is the most linear. The drawback to this are that it is in operation all the time, drawing full current even when there is no work to do. Since the devices never get a chance to cool down, this also makes the circuit more expensive to build. You need sturdier devices, larger heatsinks, etc.
In class B, the work is split up between multiple devices. When one is working, the other is not and has a chance to cool down. If there is no signal, neither device is conducting. While this allows the same work to be done at a much smaller cost, this kind of circuit introduces a very small amount of distortion when the devices are swapped. This is called crossover distortion.
So the difference between the classes is really a trade off between linearity and operating efficiency. It doesn't have anything to do with how much power is delivered to the speakers. The class A amplifier will waste alot of power to gain a slight advantage in accuracy.
To explain it in simple terms, the tube/transistor in a class A circuit has to do all the work. It biased in the middle of its operating range where it is the most linear. The drawback to this are that it is in operation all the time, drawing full current even when there is no work to do. Since the devices never get a chance to cool down, this also makes the circuit more expensive to build. You need sturdier devices, larger heatsinks, etc.
In class B, the work is split up between multiple devices. When one is working, the other is not and has a chance to cool down. If there is no signal, neither device is conducting. While this allows the same work to be done at a much smaller cost, this kind of circuit introduces a very small amount of distortion when the devices are swapped. This is called crossover distortion.
So the difference between the classes is really a trade off between linearity and operating efficiency. It doesn't have anything to do with how much power is delivered to the speakers. The class A amplifier will waste alot of power to gain a slight advantage in accuracy.