I was trying to learn what this power box was for, and I found this in the BeoLink Handbook:

"The ML Power Box is power supplied via the USB cable (USB A to USB mini B) connected to the BeoLink Converter NL/ML."

I wonder if there's some kind of grounding or static electricity issue since you don't have the power box powered by the BLC?  Is there any way you could move your PowerBox to the location of your BLC so it can be powered as described above?

Otherwise, from what you describe, my first guess would be a bad power box.  This is a new product, and it seems like a new product would be more likely to introduce a fault than old cable technology (ML, RJ45 and wall connectors have been around forever) - especially since there are no ML junction boxes in the picture.  It could also be any ML cable, connector or the BLC, but I'd ask your dealer to see if you can swap in a new a power box first.  I'd also check for kinks in any of the cables, and maybe pull off the wall connectors and make sure they don't have any lose wires.

Stan 

Hi Stan

you're very kind! That's for taking time to help me! Once I bought the BCL and the BL3500 my dealer told me that the ML Power Box just gives the required power to the ML. It actually replaces the former audio master, which did that job. Basically you don't need a audio master since then, because the little ML Power Box does the job. So far so good.

Unfortunately I can't change the position of the power... the parts are in two different rooms at the moment. I could, but I had to buy some plug adapters first (you know, it's not my apartment, and even though they built ethernet cables in the walls, they splittet the 8 wire cable into two wall outlets, that's good for 100Mbit, but not enough for the 8-wire ML system of Bang&Olufsen... so I decided to connect the two wall outlets in every room with two Y-cables. But that's another story).

Back to the main problem... I think I am one step closer to the solution. I initially used a 1.2A 5V power supplier and changed that one to a 0.5A 5V power supplier (from a digital camera)... and now: The cracking noise is almost gone... not completely, but it's hard to recognize it now. Hopefully I'll experience the same situation as soon as the BL3500 starts as alarm clock tomorrow morning. If not: I'm gonna freak out :).

Rémy

By the way: http://beointegration.com/uploaded/EN-BeoLink-handbook-v1-7.pdf

Look at page 29, there's a description of the ML Power Box.