SOUND ON SOUND

[tommytime]

I just purchased the Zoom F6 and am running some audio tests but I'm picking up an obvious (strange) frequency sound, as well as some crackling in the audio. I'm starting to wonder if I ended up with a faulty recorder.

Has anybody else experienced this?

I'm not getting this sound when plugging the same mic (NTG-3) into my other Zoom N42 recorder.

Sample Here:
https://www.dropbox.com/s/494afjmz2v7hw8i/freq.WAV?dl=0

T