[bh285]

My unit is fine in high end theater room, replace HDMI cable, check other cables and then RMA it.

Thanks, that's my best course of action. I'll replace the cables and report back.

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HDMI output is digital, the noise you describe is analog. It's a cabling issue or maybe some sort of grounding issue IMO. I've not ever experienced this with either of the NUC I have even at high volumes.

Thanks BLKMGK, your exactly right regarding digital vs analog and thus my confusion on hearing the hum at all. Grounding issue is an interesting idea. I'll check that in addition to the cables.