Mac Pro Optical Out

[dannyraul]

Got my mac connected to my logitech z5500 via the optical interface, problem is that i am getting background (sounds like electrical) interference when the amp is on and connected to the mac. I have had the z5500's connected to my other PC, PS3 and 360 and haven't had any problems. I also tried connecting the mac to the coax input via a converter and i get the same problem.

Any ideas guys?

p.s. the mac is connected to a surge protector

 

[dannyraul]

After searching on google it seems that the sub is not shielded and should be at least 2 ft away from any other electrical equipment - which it isn't as its sitting underneath my desk with everything else! The mac is on my desk and at least that far away, i don't however get these problems with my PC which is right next to the sub!