I have requested for the first device, a replacement device, since the power supply or other component was a "whirring" of itself. This was also perceptible at a distance of> 50 cm, if hardly occurred noise. Unfortunately selbiger error also occurs in the second unit. Both devices have the revision A01 with production date in January 2015. According to their Prad.de tester had no such problems, which was executed have a series of scattering.
Therefore, the above-mentioned good quality everyone gets the luck with a device has, which does not have such a problem, or the one who does not perceive it.