dynamics are not affected by phantom. common procedure is to plug in all your mics first, then enable phantom.
when done, turn off phantom first, then wait a good 10 seconds for it to ramp down, and unplug your mic(s).
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i've never had a phantom "accident", even though i've swapped mics w/ phantom on. there's also a cardinal rule about not using phantom w/ ribbons, but apparently it's only an issue (the issue being a blown ribbon) if something is wired up wrong. despite all that, i still follow what i wrote above.