That is, why can my Brainwavz B100s play much louder at a given volume setting through my computer headphone jack than they do through my SMSL Idea amp/DAC? They're 50 ohm earphones with a sensitivity of 110 db. I don't know what the power output of the Realtek ALC887 codec is, but the Idea is rated at around 35 mW at 32 ohms, and has an output impedance of .5 ohms. What's odd is, the other earphones I have, the Fiio EX1 II (16 ohms, 98 db), and the KZ Zs3 (18 ohms, 106 db) can be driven to a considerably higher volume by the Idea than by the computer. It's not a real problem- I can get more than enough volume from the B100s through the Idea- but I'd like to understand why they're so much louder through the computer headphone jack.