Got my humX in, the noise is barely audible at specific positions on the knob, and silent at others. Still find it strange the way the noise works (I hear crackling at min volume, no crackling/noise at all at around 8-10 oclock (which is perfect, as that's the volume I listen to on my th900's anyways), and crackling that gets louder as I turn the knob up past that point.
It gets fairly noticeable towards max volume, but compared to the volume of the music it would be playing at that point I'm not too worried about it.
I'd say the humx got entirely rid of the "hum", interference with my pc, and reduced the crackling noise by about 80% when just connecting the amp and dac directly to it. Still kinda confused on what in my room is causing the noise, but I'm happy with everything for sure. Good recommendation! I'll have to get around to putting other stuff onto the humx to see what else can affect it. I do have two security cameras connected to two plugs in my room, and I honestly wouldn't be surprised if it was them, but unfortunately I can't move them from where they are plugged as the wiring for them goes straight into the wall.