A popping comming from your IEM's or from the X3?
The only time a pop will come THROUGH the heapdhone is when you have your IEM's plugged into the X3 and you turn it off.
The physical clicking/pop is the relay. This is a muting relay that makes it so that the transient power on or amplifier on state doesn't create the influx in power and thus a pop that would otherwise happen.
I'm hearing pops when I plug the iem in and out into the X3. I hear it through the iem.
The device has restarted after 10 minutes of playback.
I'm tinkering with the X3 with the line out into my C&C bh and I don't hear any hissing noise anymore. I hear hissing from the headphone out jack of the X3.
My initial impression of this is pretty on the low side and I'm only judging it based on the performance side of things (headphone out, lineout, etc).