Thanks Jeff for the long winding troubleshooting! The box was indeed a suspicion. I'll be upgrading my box and testing this out in the meantime to fully confirm this as well!
Now I'm really curious how this works out.....
What do you mean by "upgrading my box"?
I still recommend to test the eq in a "trustworthy" rack,preferably from a well-known brand or the ones around here.Have never had any problems like this over all the years,I run eight racks with around 50 modules here.
Still looks to me like the problem is outside of your eq.
Best,
Udo.
Addendum:I tried to open the link on a mac running safari,did not work.Then on my ipad,worked but I can't seem to zoom in deep enough.
At least a "psu" is visible,looks like it is ac!
I wouldn't trust it,,maybe there's a supercheap smps board inside the rack.
The mains plug doesn't seem to have a safety gnd,right?
Also seems to have various link switches and insert points on (unbalanced?) jacks.
From this point on I seriously doubt the complete grounding scheme of your snackbox.