Is this the ultimate solution to everyone’s hum/noise problem? Has anyone tried this product?
You mean Morley Humno? 
I’ve only experienced hum/noise when using via 4CM and even then it was only at specific locations. I solved any hum related issues using the Ebtech Hum Eliminator and now keep a few extra on hand for if/when the need arises.
im pretty sure the solution to everyone’s hum issue is to power the unit fully before you plug in any cables to it
Is there widespread confirmation of this workaround? If so, excellent find! I ask because plugging cables into my modelers while they are turned on, although not something that never happens, goes against general best practice. That could, I suppose, potentially include expression pedal cable connection, depending on how the calibration works (different on various modelers).
There would have to be a significant payoff, like hum/noise elimination, for me to adopt this manner of device-on cable connection.
i keep mentioning it but its like no one reads it
when this unit boots up it does some kind of impedance check or something and it sets values based on whats plugged into it
SO AS A RESULT: if you have monitors plugged in or your PA system or whatever when its boots up, then it cant self regulate properly or with correct values and then you end up with hum which wouldlnt exist if you powered it on without them plugged in and let it boot up first.
if you dont have the conditions for some hum to begin with, i dont think this surfaces. For example I dont HAVE to do this at home, but when i go to my practice spot with its power if I dont do this I have hum 100% of the time and theres no fixing it (except to reboot the QC without the outputs plugged in)
there is a post here somewhere that explains how the unit scans some kind of levels on power up and sets some value based on that, and thats how the hum starts. I had this very problem and couldnt figure it out, but then i read about that function on boot, and started powering it up fully before i plugged in my QC to my PA and voila its never happened since.
FYI that part you said about expression pedals and other stuff makes sense to me. This is why when I power on my unit i dont plug in expression pedals or my instrument cables either (but i dont think its necessary, im still not taking any chances).
for what its worth last week i did plug in my expression pedal before powering on the unit and the pedal worked fine, and no hum on my output.
Wait… hold up.
If you have cables plugged into the QC while it powers up, it hums?
So if you have your QC on a board, with patch cables literally plugged in 100% of the time, that’s going to make it hum?
OR does this only happen if it’s plugged into a speaker first?
I have my QC on a board with an fx loop and two inputs and outputs going to a junction box… if the outs are not yet plugged into a speaker when I turn it on, am I (theoretically) in the clear?
as far as I know this is only in regards to CABLES PLUGGED INTO THE OUTPUTS when you power it up and only an issue if the power is an issue for you already
im 95% sure its only regarding being plugged into powered speakers / PA etc and only the outputs, but i dont care enough to try other scenarios.
i know this works for me and i know if i dont do this it makes hum that never goes away
it has something to do with the way that is uses the kind of power that it has. it has to self regulate some check on boot, because it doesnt have the kind of power that everyone complains that they wish it did