I've got a problem with the phantom power on just one channel on my RM16AI, latest firmware etcetc. If I connect a DI box to that channel with phantom power on, I get a hiss on that channel that will rise and fall with the fader and is present in all the output channels, turn the phantom power off and the hiss goes away. Connect the DI box to any of the other analogue input channels with the gain and EQs set the same and there isn't any hiss when the phantom power is turned on. The suspect channel will work fine with all the other signal sources I have which don't require phantom power. I've worked around it by using that channel for something that doesn't need the phantom power. Has anyone else had this problem, its there a fix that doesn't require the mixer going back for repair, and does anyone know how such a problem might have happened?