I had a planar magnetic headphone. It sounded god awful from one dac/amp I had. Even though I could get them loud enough, no problem. Them I tried on a much more powerful dac/amp and they sounded awesome! I remember there being a website where you could calculate how much juice you needed for specific headphones. In my experience it's not about how loud you can get them, there are other specs at play. Planars are power hungry, and in my experience need a specific powerful dac/amp to get a full bodied and clean sound.