Price / Performance Top, sparingly, but PSU whistles

At the function, there is nothing to complain about, I have nothing negative bemert,

For power supply:
Previously, the devices have a transformer. This was difficult, current consumed even when the power was off and she likes hummed with 50Hz. The new generation of switching power supplies generate a high frequency AC voltage so that a very small transformer ranges and the efficiency is still higher. These power supplies consume no power when no load is connected. The most common problem: radio frequency, unpleasant whistling just in the audible range. And that's the case, unfortunately, in my device. In exchange, a device to get with fewer whistles seem to be hit or miss. Since the identical devices also produce the same frequency of the AC voltage is not surprised.
I'll have a look if I can find a replacement power supply with less noise, but that's also somewhere the price advantage to naught. With the big brother TL-SG1016 I have no problem, because since the power supply is built into the metal housing.