Mic input on Helix floor unit in Helix Posted March 1, 2018 Judging by reports, the mic input circuitry seems to be a bit fragile. There are two main rules. Make sure you don't use a shorted cable, and don't plug or unplug the microphone while the Helix is on and set to provide phantom power to the mic. Glad I read this. I've been hotplugging my condenser since I got my new helix last week. Won't be doing that from now on.