Chassis grounding has become a popular enhancement . The Cascade has a post for this purpose. Would chassis or signal grounding to the Director be beneficial or is it a moot point with the fiber optic connection to the DAC.
I know I posted this in the other thread, but here it is again:
We absolutely want isolation between the DD and the Analog converter. That being said, if you can improve the performance of the DD independently, we will encourage that ground treatment. But, please avoid grounding schemes that simply link the two chassis together. Better is better. If you can tune some extra performance anywhere in the system, that will usually have sonic benefits.