Class A/AB and class AB are the same thing. At lower powers the amp is class A and at higher power class B. How much class A depends on the amount of bias and can range from less that a watt to lots of watts which is rare.
But even a low efficiency speaker say 82 dB plays a continuous 82 dB with a watt and that's fairly loud so an amp with just 1 watt class A goes out of class A only on peaks which last only a very short time. So class AB amps are in class A most of the time.
Most amps even those costing 6 figures are class AB and well designed class AB amps sound awfully good these days and have more head room than pure(never go into class AB) class A amps which are extremely rare except for single ended amps which must be class A and single ended amps are very low power.
By the way almost all push/pull class A amps go into AB at very high powers especially into low impedance loads. For instance Class A Pass amps go into AB. But they only give you the class A rating in their ads. They produce twice as much power usually total but it's AB then. The only
push/pull true class A amp I know of was he old Mark Levinson ML2 which was 25 watts class A into 8 ohms and still class A at 100 watts into 2 ohms.
Then there's the sliding bias amps which could be called class A but some argue they aren't true class A. I'm not going into that discussion.
But even a low efficiency speaker say 82 dB plays a continuous 82 dB with a watt and that's fairly loud so an amp with just 1 watt class A goes out of class A only on peaks which last only a very short time. So class AB amps are in class A most of the time.
Most amps even those costing 6 figures are class AB and well designed class AB amps sound awfully good these days and have more head room than pure(never go into class AB) class A amps which are extremely rare except for single ended amps which must be class A and single ended amps are very low power.
By the way almost all push/pull class A amps go into AB at very high powers especially into low impedance loads. For instance Class A Pass amps go into AB. But they only give you the class A rating in their ads. They produce twice as much power usually total but it's AB then. The only
push/pull true class A amp I know of was he old Mark Levinson ML2 which was 25 watts class A into 8 ohms and still class A at 100 watts into 2 ohms.
Then there's the sliding bias amps which could be called class A but some argue they aren't true class A. I'm not going into that discussion.