What? This english is so hard for me, ( google translate ) i must install itunes yes?Install iTunes(for CoreAudioAAC encoder,FAAC encoder sounds sh*t),and increase bitrate,try it.
If you don't use advanced output mode,then you may try lossless,or nearly lossless quality setting
I use focusrite scarlett 6i6 and AT2020,OBS sounds fine with CoreAudioAAC