I have a pair of mark levinson 33h mono blocks each one weighs over two hundred pounds they double every time the impedance is halved and they are stable to 1/2 an ohm. They stay class a all the time and when they were tested the output power was limited by the input power. Each one the minimum power requirements are two dedicated 20 amp circuits. They do not switch to an ab amplifier and there power doubles not halves as the impedance is halved.
CLASS A POWER RATINGS
In well designed SS class A power amps I was told that although power could increase to double in class AB mode from speaker demands of 8 ohms to 4 ohms, class A suffered to be cut in half.
For example a class A denominated amp rated at 50 watts class A into 8 ohms would double to 100 watts class AB into a 4 ohm load but only have 25 watts of class A power before switching to class AB.
But I've noticed of late claims of manufacturers stating their amps double their class A power as impedance demands are halved.
So is the explanation that technology has advanced ?