I can not see the point in running the NUC without mSATA, RAM and OS. I guess the noise in your audio out would disappear with everything installed.
The high pitch noise have been described in an earlier thread.
I agree with you the fan noise in unbearable. I have recorded 10 sec. (attached file).
Fan noise.wma.zip 139.4 K
The situation is the same with or without RAM and mSATA installed.
As for the fan noise, your sample seems to be taken from my box, same here.
I had this high pitch noise as well when the unit was off. See my thread,
I returned the NUC as faulty and haven't bought another one just yet. I am afraid this noise is present in all the units and most people are just not aware of it.