Digital noise on unused audio channel when recording video on R7

[spyder0069]

Problem:

Anytime I record video on the Canon R7 if one channel is unused there is digital data style noise that appears faintly in the recording.

How I came about it:

Initially I found this when I purchased a tascam CA-XLR2d-C adapter and thought it was the adapter that was the problem.  It did not matter which channel (left or right) was unused you could hear the digital noise on the "empty" track.  I then removed that adapter and tried several mics directly into the mic jack on the R7 with the same results.  If the mic is set up to record to both channels there is no problem.  If you only have it connected to one channel you get the noise.  

I did try changing the settings such as from 4k down to FHD and 60 to 24fps with no change. 

Can anyone else perform this test and see if you have the same problem?  I did update the camera to the latest firmware.

I have a sample of it uploaded to youtube but not sure if the canon forum allows links.

[Anonymous]

I replied earlier to try a mono to stereo 1/8" mic cable adaptor to supply a single channel mic signal to both left and right channels on the camera. This might work.

[spyder0069]

I tried an adapter that was a mono plug with a stereo jack and plugged the lav mic into that.  This did not work.  Did not pass any audio from the mic to the camera.  I am not sure why.  I would have expected the one channel to go through the tip and the other be attached to ground from the longer barrel on the plug.   I have a different adapter that is on the way which is a 3.5mm stereo plug to a mono jack.  It will be interesting to see the results with that one.  Either way the result remains the same as far as canon being unable to handle a single audio source on one channel at least with my R7 that appears to be the case.  Its not a show stopper but if someone was using the tascam adapter while recording two people and wanted to dial down the one chanel (muting) it then they would be left with that noise on the recording for that channel.  Fixable in post but shouldn't be there to begin with.  I can perform a similar test with my GH5 with no issues.  

[Anonymous]

Yes, it would have to be the other way around, stereo plug to the camera mic input, mono jack to the mono microphone.

Also, make sure that the plug to the camera mic input is being fully seated in the camera jack. I seem to recall that it is somewhat difficult to fully seat the plug.