In principle the Concept F is a very low-noise system. In the high range area, very high-resolution quality speaker systems can 'expose' the defective quality of a signal source (e.g. from MP3 files or analogue cassette recordings) that is hardly noticeable on lower quality speakers.
You can check the basic noise level by connecting a signal, via a cinch cable, from an external source that is guaranteed to be good quality – such as a music CD e.g. on a portable CD player – to the Aux L/R input on the subwoofer. If all of the satellites are now playing noise-free, it is because they weren't receiving the right signal before. Either the cinch cable is defective (try swapping them around) or the output of your source appliance is not producing an adequate signal.
However, if you continue to hear increased noise on this channel there is possibly a fault in the Concept F. Please check which satellites are affected by changing the satellites around and to find out whether the satellite or the subwoofer electronics are producing excessive noise. If the fault "moves" with the satellite the satellite is the problem. On the other hand, if the hissing remains on the same channel, the subwoofer amplifier electronics are the cause.
You can check the basic noise level by connecting a signal, via a cinch cable, from an external source that is guaranteed to be good quality – such as a music CD e.g. on a portable CD player – to the Aux L/R input on the subwoofer. If all of the satellites are now playing noise-free, it is because they weren't receiving the right signal before. Either the cinch cable is defective (try swapping them around) or the output of your source appliance is not producing an adequate signal.
However, if you continue to hear increased noise on this channel there is possibly a fault in the Concept F. Please check which satellites are affected by changing the satellites around and to find out whether the satellite or the subwoofer electronics are producing excessive noise. If the fault "moves" with the satellite the satellite is the problem. On the other hand, if the hissing remains on the same channel, the subwoofer amplifier electronics are the cause.