This is my first time posting so I apologize if this is the wrong forum for the subject matter.
A few seconds after I turn off the phantom power to my TLM 193 I get a high to low pitched sign wave coming from the channel it's plugged into. It last for 30 seconds or so. If I unplug the mic or pull the fader or gain down it stops right away. I'm using an RME Babyface interface with their TotalMixFX software. This doesn't happen with my other condenser mic.
Any idea what might be causing this? Should I send the mic for servicing?