When a powered off Sennheiser G3 bodypack is attached to the EX1r camera, a 500Hz whine can be heard on that channel and is recorded. It does not occur when a bodypack is connected to the camera via a field mixer. Is this the camera, body pack or works as designed?
EPILOG: This is a Sony EX1r camera issue and may be a problem on other models. The problem is audio interference from the EVF. Even when new, the whine can be heard in the headphones (not the recording) whenever the LCD is closed (ergo the EVF is on). Something about the EX1r design results in a louder whine in the recorded channel when a powered off bodypack is attached at MIC impedance. Turning off the EVF or using MIC+48 impedance (even though the bodypack doesn't need phantom power) resolves the issue of recorded interference. It's still faint in the headphones but not in the recording.