[iAudio X5] Little "click" when boot ends and at start of playback

[squonk]

Hi!
I'm still using my glorious iAudio X5L.
After the CFMod I'm happy with 128gb of storage and the beautiful sound from Rockbox 3.13.
I write here about a little problem that was there also with the HDD installed, so I think is not related to the CFMod.

When the boot process ends, I listen a little "click" in my earphone.
This little click is present also when I start the playback of a file.
Very rarely I hear the click even between tracks at the beginning of the next track.
Why this?

Almost all of my file consists of mp3 I've created by myself with Lame VBR V2 from lossless sources that do not have the click that I hear.

Is a problem of my player or Rockbox related?
Any suggestion?

[saratoga]

DAC powering on or off maybe?  I've never used that player, but a click is pretty common when a DAC powers up.  Not sure why you'd hear it during a track change though.

[squonk]

Thank you for the answer!
Sorry for aks this: what do you mean with "DAC powering on or off"? I don't know if this is related to some system settings, I don't find anything about this...