Sony ECM-77 hiss with a Sony PMW-EX1
 

I'm having trouble with hiss using ECM-77s plugged into my Sony PMW-EX1. Does anyone have any experience with similar problems and a fix?

I've used these Mics many times before with other gear and never had such problems. The camera gain is set to -59dB mic input and I'm still pushng the manual gain control hard to get decent level. Older ECM-44s seem not to have this problem. I've tried powering the mics with their internal batteries and not phantom power and that doesn't seem to make a difference. Any ideas?