Under normal working conditions, phantom power will not damage a Royer ribbon. Phantom power is actually required for operation on our active R-122 and SF-24 microphones. The two exceptions are miswired cables and "live cross patching" on a patch bay. When a mic line is crossed-patched at the patch bay, there is a temporary short that occurs as the jack is being inserted. If 48volts are present, a damaging voltage spike can be sent to the microphone. This can cause excessive stretching of the ribbon. This is also not recommended for condenser microphones. Solution - make sure the mic is unplugged or phantom is turned off before cross patching mics at the bay. Also see Ribbon Microphones and Phantom Power.