As I understand it ONLY the case of NOS1 is connected to PE and everything inside NOS1 is NOT connected to the case. So as far as I can understand from what you have said the sound card inside NOS1 is connected to the PC earth via the DVI cable and the line output amp card earth is connected to the SET power amps signal earth via the RCA interconnects.
Maybe I don't understand what the real question is, but the situation is this (for the DACs with meters) :
Nothing is explicitly connected to the case, except for one thing :
DVI cable shield (via a capacitor, which should work with the same effect as your 10R resistor -> slowing down current paths to external, so they stay inside).
However, within the PCI arrangement, this shield "ground" connects to the digital signal ground which in the end is (viavia) of course connected to all internal floating ground.
This all means that when you'd measure the connection between signal ground (e.g. on the RCA cable) to PE, you will see the 100% connection (0 Ohm). Still all is arranged so that nothing is spit from the DAC, because it just doesn't spit (this is fair to say).
The DVI shield connection is necessary because otherwise PC noise will travel over the data line (more theory than noticed practice).
Peter
