Analog audio noise

[Vairetz]

Hi, I use my raspberry pi as media center and i connect my aplifier to analog output, but when I'm watching a film or I'm listening to music in background I listen an annoying noise (an hum).. Can I fix it? How can I do?

[Burngate]

There are a lot of sources of hum, so a definitive diagnosis is difficult.

If you're using a standard wall-wart to power the Pi, there shouldn't be a ground-loop, unless you're also connected to a grounded TV/monitor.
However, if that's the situation, try disconnecting the TV/monitor and see if it improves.

Also, if you're using a four-pole trrs plug in the Pi, are you sure it's wired correctly? (a standard audio-only three-pole plug won't have that problem)

[Vairetz]

I use a threepole cable, raspberry now is connected to pc monitor with hdmi and audio jack to amplifier.I try to change the cable but the situation not change