Hi @Cesare,
Is it all files that you play from USB?
What format are the files that are on your USB sticks?
Are they all the same format?
Where were they sourced from?
Do you have a UPnP server on your network and if so do you get the same noises when you play the files via UPnP?
Are the noises that you hear always at the same places in the files? Are they at the start of playback and at track change or are they in the middle of the tracks?
If you contact [email protected] then it would be good to get access to some of those files to see if we can recreate the issue and / or take a look at the files themselves?
BR
Phil