I know there are few posts discussing about this problem. But my case is little unique I think. So thought of sharing if anyone of you have any clue.
I just bought a MacMini (with fusion i/o) to experiment with the USB input of DS, first time. Otherwise I am happy with bridge so far.
Here are the connection details I connect the MacMini to my TV over HDMI, the MacMini is also connected to my router which DS is connected with too. My USB cable is not high end - could get one of around $25 USD from radio shack.
I use only one wall socket to connect all my equipments. There is one high end stripper connected to the wall socket and then I use one more stripper from there as on one stripper I cannot connect all my equipments. In the main stripper I’ve my power amplifiers (two of them, monoblocks) plugged in. The MacMini is also connected to that. The DS, Preamplifier and TV are connected to the second stripper.
And I hear the humming noise from the speaker as soon as I connect any one of the USB ports of MacMini to DS’s USB port. The noise goes away as soon as I disconnect the same.
But to me more surprising are the following observations -
If I disconnect the HDMI connection from MacMini to TV, the sound goes away. This is even if the USB ports of MacMini is still connected to DS’s USB port.
Even if I disconnect power cables of all of three, MacMini, DS and TV, the sound still comes from the speaker. Only if I disconnect either the HDMI cable or the USB cable from MacMini the sound goes away.
Any idea ? Is it more a grounding problem in MacMini ? I need to return the MacMini if this does not work.