Faulty sound with external mic connected to EOS 77D

[ShellGeo26]

I have been recording vlogs with my EOS 77D and external microphone connected via the headphone jack. For a couple of weeks all has been working fine. As of two days ago, the audio recording has horrendous sounds (check attached video). 

I have already tested the external microphone with another device and it worked fine. I have tested the camera in video recording without the external mic and it also did not produce the faulty sounds (but the audio quality recorded from the 77D's mic is not good enough for the vlog).

Any advice would be highly appreciated. TIA!

[shadowsports]

Greetings,

I've never heard a sound like that.  Typically you might hear a hum if there's a ground issue, or the sound of the lens motor when it's focusing.  

Since you've tested the microphone elsewhere and it's working and the internal mic on the 77D is working, the issue appears to be with the camera.  

Try formatting the card and retesting with the microphone.  You may want to reset the cameras settings too.  If this fails I would test with another microphone on the camera.  At that point you should be able to conclude if there is a problem with the audio circuit.