Nietzschelover

I have a new 2011 Mac Mini (w/Lion). My hard drive is connected via firewire. I use port 1 (the one closest to the power button) as an output to my usb to s/pdif converter. I turned off the infrared receiver shared on the bus. Before I start switching things all around to find the "best sounding" USB output port, has anyone found, already, that a different port sounds better?