Ok thanks, I did not think of a disadvantage of this modification so far. I will keep that in mind.
The click has to come from the output capacitors because they are discharged. When power goes on, the level of the output amp is lifted to the middle voltage between the amp supply (9V) and GND (0V), around 4.5V. The caps have to be charged because the headphones will be connected to GND and we don't want to have 4.5V DC on our headphones. The charging of the capacitors is done by an internal resistor i guess, but it is very slow. As soon as the headphones are connected (click at playback), they will charge the caps very quickly but this is neither good for low impedance headphones nor your ears. So I think that you have the same effect when you connect your earphones right after startup (after the click).
So here is my old picture again:
I think this schematic is not correct but one day I will open the player to see how it really is (I work with electronics every day, so I'm not afraid of damaging anything). I think that there could be a simple possibility to add a lower Resistor to charge the output caps quickly. The relay has 3 connectors (not 2 like in the picture): "com", "no" and "nc" and if iBasso was smart, they connected the capacitor to the "com" and a resistor could be connected to the "nc" pin of the relay to gnd. I will write when I know more.
Edited by cholero - 9/1/14 at 4:53am