hiss while playing flac files

[ecayl]

Hi everyone:
A few days ago i started to listen music on the rpi, i use both runeaudio and the iqaudio dac without any issues. But as soon i started to play flac files appear a hiss which piss me off. At higher volumes the noises seems to fade away or at least is cover by the music so it's only a problem when i use my headphones.
The same files were played on my pc without that annoying sound.
Any ideas why this happen?
Is there anything i can do?
regards

[hondagx35]

[ecayl]

[hondagx35]

[ecayl]

Thanks for your reply i'll do what you said
btw: do you know why there's only hiss when i play flac files? Neither mp3 or wma files present this noise. I'm very curious about it