Headphone jack noise

[IntellEJent]

The headphone jack of my mbp emits clicking noises when I plug my MBP into external speakers. This doesn't really matter for headphones, as the headphones I use are USB and the USB headphones work perfectly. However, no matter when I'm in OS X or windows (although in windows this sound is more of a humming sound) this sound occurs, even if sound is muted. What could be the root of this problem? Thanks.

EDIT: This is the first time I have ever used the headphone jack.

EDIT: Delete. PEBKAC

 

[infernohellion]

This is normal (isn't it).

For all the previous Mac I own, I can always hear the clicking sound at some point.

 

[IntellEJent]

Well, the sound card isn't that great in the mbp. If I set it higher than a pretty low volume, the clicking noise becomes really apparent which is quite annoying. Is this normal?

 

[Jethryn Freyman]

It's poor quality audio hardware inside your MBP. It's a known issue on the Santa Rosa model.