Clicking noise (every ~15 seconds)

Hi,

I've got 2 new TB Displays and the second one in the Audio-Chain (NOT the Display-Chain) makes a clicking noise every f*** 15 seconds.

I've already replaced the displays but the same noise comes out of the (left) speaker of the 2nd display in the Audio-Chain.

I've also used another plug-socket without any results, I've also tried to switch the chaining - wihout any results too.

These displays are the only way for me to connect my late 2011 MBP with 2 HighRes displays, but 900€ for displays which makes this clicking noise is unacceptable.

MBP late 2011 17"

OSX Maverics (latest DEV release)

16GB RAM

Samsung 840 Pro SSD

Best

Tino