Just keep in mind, this amp puts out twice the power of the Hypex amps in question (and more than twice that of the Purifi). Which is more important, .002% vs .001% THD or 250 watts vs 400 watts? I know there has been some comparisons of .006% vs .001% but that isn't the right comparison since Amir measures at 5 watts. This is actually why. Gene prefers to do a 1 watt test since we listen at or below 1 watt quite a bit. However, most amps are pretty noise limited at 1 watt, so he does 5 watts. That does a better job highlighting the area where the amp is no longer noise limited and is operating in it's most linear range. In this case, the 5 watt test puts it at something like .002% or less. I think I got .0025% into 4 ohms for 10 watts. I can't recall what I posted, it was something like that. Point is, this amp has ever so slightly higher noise and distortion, but produces quite a bit more maximum power.\n\n\n\nThe Purifi IET400A 425W @ 1% THD, 4Ω. Single channel\n\nIf you look at ASR's graph, it is pretty close, 257 W both channels driven, at 0.0002% THD. If you look to 1%, it did get close to 400 W.