I'm recording drum tracks over the next few weeks. It used to work fine, now one of my condenser mics likes to dip in power while recording. For example, the right comes through just fine with an even frequency, the left comes through, but the frequency drops in size/volume for a few seconds, then returns.

I have an EMU 1820 interface with all 8 inputs running ASIO to Audition 3. The overheads are running off of the on board phantom power. I tried switching XLRs as well as reversing the inputs and the problem followed the mic so It's not the interface or cables as far as I can tell. I also hooked up a tiny preamp with phantom power and that seemed to give me two even frequencies, however, even though they were recording as low as -9DBmax, and without visible clipping, I heard audible clippage.

Can anyone give me direction? Why is the mic cutting out and/or why is there audible clipping when none visible?