Hi, for years I've had the Rack Gizmo, since it first came out. With that, I've had a Marshall EL84 20/20, a few stereo racks collected along the way, and finally have 2 iso cabs loaded with greenbacks. So for the Rack Gizmo, I need to figure out what I'm doing wrong where only one channel is going through. Down below I will post what my current test setup is, and what we can do to identify why it may not be working. I do have quite a few TRS cables, in addition to insert cables.