Originally Posted by dolifant
From what you say, the Qualia can be fully driven by a headphone amp that outputs 500mW. In fact that is 4X the useful power required, maybe really 30X, since you should not listen for long at even 112 dB (16mW).
So an amplifier whose first 16, maybe 32mW (115dB) is clean and linear should drive the Qualias well. If, as KG says you need 10dB headroom to do this, that would mean being able to drive the cans easily to, say 125 dB,meaning roughly3 more doublings of the power, equaling 256 mW. So a 500mW amp seems quite adequate. I bet there are many that can do that, even into an impedance of 70 ohms. Does it really take a monster amplifier? The calculations you gave seem to say not. Of course, there might be unfavorable phase angles at certain frequencies, like speakers.
What is all this discussion about needing huge power supplies, etc.?
I can understand wanting a very good quality amp for a great set of cans, but power quantity is not the real issue, is it?
Just two amp designers with different view of design.