Don't quote me here but I believe something about zero 2nd and 3rd? harmonic distortion. I forget, but basically it is the cleanest, distortion free, noise free signal you can feed a pair of speakers with. It would not surprise me if someone does not immediately like the AHB2, it is next level but out brains are use to what we are use to and so it may sound bad to someone at first. Just crank it up a little more than normal, and give it a couple days and when you start to realize all the dynamics are there and the background is a black hole, the detail starts to pop out at you, and the dimensional imaging is incredible. I have two systems, both I love equally for what they do for me, but when I want to experience the best 2ch music possible, I go to my AHB2/Cornwall combo, the imaging makes it sound like the musician's are in the room with me, and I can listen for hours. Especially great for classical music too. Anyways do not want to go down this subjective route and stay on track, the AHB2 is for me the sweet spot, looks wise and performance wise. It does have a quirk for me but nothing deal breaking and in fact, its a bonus, there are no RCA connectors and the binding posts on it are super nice, I have the Benchmark Cable using neutrik connected to mine. It also had adjustable gain settings, to get the best performance you need to used balanced connections at studio powers so that it can play its cleanest.