Question about headphones...

You know when you plug headphones into like speakers, theres this humming noise? Well my new speakers barely have it, very quiet compared to the stock ones I used.

Well before, I never heard noise from the front panel plug (connected directly to the sound card), but now the noise is even louder than the plug on my speakers, is there anyway I can fix it or is it broken?

Also, is there much of a quality difference if I plugged my headphones directly into the front panel (which is connected directly to the sound card) and plugging it into my speaker which is connected to the sound card?

Cause its quieter with my speakers and if there isn't, I'll just plug it in there instead.