Class A isn't necessarily any better than Class B, and "Class" A/B isn't really a class but an amp the flip-flops between the two. "Class" A/B will always have more distortion than a well optimized Class B, all other thing being more or less equal. And between the A and B, alot of it depends on how well its done. I've seen Class A with 10% THD and class B with .0005% THD at most frequencies. Not to mention all the other variables of an amplifier like slew rate, intermodulation distortion, damping factors, etc. While the switching distorion found in Class B (and technically A/B) is the most offensive type, its levels can still be designed so low that the audible difference between the two classes is negligiable. Randy Slone from Seal Electronics puts it ok in his FAQ:
7. How about Class-A audio power amplifiers? Don't they sound better than Class-B designs?
To make the statement that one amplifier sounds better than another poses the requirement that the differences in sonic reproduction be discernable to the human ear. It has been proven that the human ear is capable of detecting high-order odd harmonic distortion as low as 0.3%. Crossover distortion, as produced by Class-B operation, is the worst kind of distortion, being high-order odd harmonics across the entire audio bandwidth and existent at virtually all signal levels. The worst-case conditions for crossover distortion is at very low volume levels at high frequencies (i.e. close to 20 kHz). Even under these extremes, several of the amplifier kits in this catalog are typically capable of THD levels better than 7 times lower than the minimum audible level. Therefore, in these or similar designs, it is quite impossible to detect a difference between Class-A and Class-B operation based on human perception, as long as all other performance variables are identical.
In summation: you can use a Class B amplifier, or any amplifier designed for home audio, with horns and still get very good sound if its a well designed amp.
7. How about Class-A audio power amplifiers? Don't they sound better than Class-B designs?
To make the statement that one amplifier sounds better than another poses the requirement that the differences in sonic reproduction be discernable to the human ear. It has been proven that the human ear is capable of detecting high-order odd harmonic distortion as low as 0.3%. Crossover distortion, as produced by Class-B operation, is the worst kind of distortion, being high-order odd harmonics across the entire audio bandwidth and existent at virtually all signal levels. The worst-case conditions for crossover distortion is at very low volume levels at high frequencies (i.e. close to 20 kHz). Even under these extremes, several of the amplifier kits in this catalog are typically capable of THD levels better than 7 times lower than the minimum audible level. Therefore, in these or similar designs, it is quite impossible to detect a difference between Class-A and Class-B operation based on human perception, as long as all other performance variables are identical.
In summation: you can use a Class B amplifier, or any amplifier designed for home audio, with horns and still get very good sound if its a well designed amp.