I don't have my A16 just yet(Kickstarter backer #174) but my understanding from a forum post on headfi is that there is a headphone gain switch next to the volume knob. The gain, which can be set to low, mid or hi, is set by default to low. There's also a caveat that you should not have the headphones plugged in when you reset the gain, otherwise you will get an unpleasant low pop coming through the headphones. Hope this helps!I finally got the A16 to output from the 16 channel analogue, I hadn't set the right software switch. The problem I now have is that the signal level is so low its barely audible! So I need to find what else I haven't switched on in the A16 settings