
Thanks for clearing up the input impedance of the FM!
I am not trying to resolve a ground loop, I remember reading about the floating shield a long time ago!
For the Belden it looks like cfx found Mouser Norway which is really Mouser Sweden

As for CPS1 I have tried that with my HAS and my FM with FW 2.0 with no issues. If you are using a Sigma supergun I would add the missing ground to pins: 27,28, e & F. In addition I would put a jumper between Frame Ground and 0V on your PSU.