Hiss at End of Tracks

Hi, I have a Node N134 and I get hiss/a soft weird high frequency squeal at the end of tracks when the music fades out. It is possible it is the period between tracks. It is hard to tell exactly. 
When this has happened in the past, dropping power for 30 seconds and booting back up would solve it. But not this time. I upgraded to the latest firmware. I would like to solve this.