Mac Pro 6 core loud pops trough speakers?

[bojangles]

Hi everyone,

recently i ordered a new macpro 6-core, all was looking good but while setting it up there was this loud pop/crack trough the speakers, at first i tought its probably a cable issue or amplifier issue, but after like 40min. another loud pop,
just to make sure i check all the cables and amplifier by hooking them up on my old computer and everything seemed to work perfectly. Hooked it back to the MP and again this loud pop.

i also get these loud random pops trough the macpro's internal build in speakers while no other external audio hardware is plugged in, tryed removing the software and did a clean re-install. even when i have the headphones plugged into the fron of the mac i get these crack/pops trough the headphones.

Called Apple and they shipped me a new one...now here's the weird part, this replacement has the exact same problem, is this like a coincidence or is there some other explanation for these loud pops (best to compare to the pop you get when taking out a jack that's plugged into the amplifier whit the volume up)

Plugging in a usb audio interface seems to take care of the problem. Is this a Mac hardware related problem, dodgy sound card or motherboard chipset or is it something else.

Maybe someone here knows what the problem is and knows how to fix it, because the people at Apple claim they never heard of this problem.

thanks in advance everyone