Lurker0
Headphoneus Supremus
When not used, DAC and analog parts, including headphone amplifiers, are turned off, to save battery power. What you hear is a transitional process in the amplifier when its power turns on or off. Though it is possible to implement delayed switches (relays), like it was done in DX50 and DX90, there is an opinion that it may have negative impact on the sound.but sometimes, when i start listening or i pause, i listen a loud pop
So, it's a feature by design.