October 27, 2014 at 5:47PM
Audio hum when using an external monitor
I'm getting a constant "hum" in my audio when recording sound into the BMPCC with an external monitor attached. Up until now, I've been able to get clean audio out of the BMPCC using the Rode NTG-2 into the JuicedLink RM202 into the camera. I just recently added a SmallHD DP4 to this setup, however as soon as I turn on the monitor, I get a hum. Interestingly, the hum gets slightly softer when I touch the preamp or the camera body.
So far, I've tried the following to resolve the problem:
- Replaced the cable from the preamp to the camera
- Replaced the HDMI cable from the monitor to the camera
- Tried using a different monitor
- Tried using the DP4 running off batteries / plugged into the wall
- Tried both "Line" and "Mic" settings in the camera
- Tried using a Rode VideoMic
Using the VideoMic made the hum go away, however I would like to make this setup work with the preamp and understand what the problem is. Perhaps this is caused by some type of grounding or signal issue?