All of our current gear (and much of our older gear as well) has an internal international power supply. Before plugging it in or powering it on, flip the small red switch on the right side of the unit to 115v or 230v as needed.
The exceptions to this are:
If a unit is accidently plugged in or powered on when the voltage switch is set incorrectly, the fuse may be blown or the unit may be damaged. In that event, please see What kind of fuse does my MOTU hardware use? for information on the type of fuse needed. If the problem persists, please contact MOTU Tech Support.