@Pjetrof
Yes clipping would give really bad distortion... But, just because there is no clipping, doesn't mean there is no distortion.
You may listen with a dishwasher going in the background and mask some of the distortion of an average amplifier or you may not be willing to change out upstream components that are limiting the performance of an amplifier like the AHB2. Imagine the dynamic range you'd lose by hooking the AHB2 to an AVR for example, versus a traditional DAC.
The AHB2 happens to have the lowest distortion of any amp that I've seen measurements for, and is the worlds best from a measurement perspective. It is so well designed, that if a lower distortion amp does come along, you really wouldn't be able to hear a difference and you will be limited by other components in the signal chain, room noise and acoustics, etc...
There are certain amplifiers like the AHB2 that are so well designed that they indeed sound more accurate; even non-musicians like myself can hear the difference. Most amplifiers have a SINAD in the 76dB range, so it shouldn't surprise anyone that if you have a quiet well treated room, somewhat sensitive speakers and a nice DAC, you can hear almost a 40dB improvement (and note that Amir's measurements are at 5 watts so it is a very fair comparison between the amps, and performance at lower wattages do make the most practical difference in real world performance).
Hopefully you aren't offended by anyone here trying to help. The simplistic view found on sites such as avsforum that all amps sound the same because only amplitude and frequency range are important and that only things like clipping matter is not the entire story. This site happens to have a large number of technical experts and a very bright owner and electrical engineer who has leading edge test equipment.