We have a strange hissing sound that manifests occasionally in one of the channels of a church auditorium. Once it starts, it doesn't go away. Unplugging and replugging the microphone seems to make it go away perhaps every time. Briefly power cycling the pre-amp (in at least the most recent occurrence) does not make it go away.
It first started happening last year, once every several weeks. It started happening more often, and based on some comments on a forum somewhere I replaced the microphone in September. We had no more problems until mid April when it happened again.
Perhaps it is just the microphone again, but it's so new and the old one lasted so long (15 years) that I am concerned there may be something else in the system that is either the source of the issues or could be damaging the microphone.
It only happens on this one channel.
Here is a sample of the noise in a recent occurrence. We were playing with the volume a little at the beginning of the recording, hoping it would go away, and there's a pop when we turned off the power amp, but other than that it's exactly what our problem is.
- Audiotechnica U859Q condenser gooseneck mic (replaced Sep 2014)
- Audiotechnica AT8646 shock mount plate (replaced January 2015)
- ~6ft extension wire with XLR plug
- XLR jack and in-building wiring, approximately 100ft
- Peavy MMA 800T pre-amp