Though all our synthesizers utilize voltage protection at the USB port, it is NOT recommended to use powered USB hubs with any of our instruments when connecting them for USB MIDI. Overpowered USB hubs could send an errant voltage spike that could damage the port, thus requiring the main board to be repaired.
An alternative to a powered USB hub is to try a USB hub connected directly to your computer. In this instance, the hub is using only the power from your computer, rather than drawing from a wall outlet which may not be as well regulated as a computer's USB port.
Phantom power (+48V) is traditionally used with condenser microphones (XLR connections) and is not intended to be applied to instruments like synthesizers. The purpose of phantom power is to apply a voltage to the pre-amp INSIDE a condenser microphone to bring it up to an acceptable level for recording. This is not needed with a synthesizer since the outputs are already line level. Therefore applying phantom power to the output jacks WILL likely overload them and cause severe damage.
Though phantom power is normally used with XLR connections, there may be cases where your high end mixer or audio interface has only this type of input. Be sure to check that your mixer or audio interface phantom power is not engaged when connected to any of our synthesizers. It's also good to note that our instruments output a "hot" -10dBV level signal: not quite as high as +4dBu, and not quite as low as nominal -10dBV. Either way, the output level should suffice for normal recording through your audio interface and/or mixer. There are numerous articles online regarding the difference between line and instrument levels, including this one from Focusrite:
Ultimately, consult your mixer or audio interface manual for details regarding phantom power.