I have grounded all 7 of my components' chassis together. This has been sufficient to reduce the differential chassis voltages from a maximum of 35mV to about 2mV. Both of my preamps have a particularly low resistance between their chassis and AC ground so an additional external ground to the outlet is not necessary. I also have dedicated wiring back to my breaker box which eliminates the temptation of running a risky separate ground, as Gs5556 points out above.
Joe - keep in mind that for many components, AC ground and chassis ground are tied together. Floating components have become rather rare these days.
As far as sound quality resulting from the grounding, it clearly improved, pun intended. I was very impressed with the improvement I got from grounding my Koras in particular and it virtually eliminated the tiny amount of ground hum I had in my MC240. I highly recommend doing this in any system so long as it doesn't create a hum problem of its own.
Arthur
Joe - keep in mind that for many components, AC ground and chassis ground are tied together. Floating components have become rather rare these days.
As far as sound quality resulting from the grounding, it clearly improved, pun intended. I was very impressed with the improvement I got from grounding my Koras in particular and it virtually eliminated the tiny amount of ground hum I had in my MC240. I highly recommend doing this in any system so long as it doesn't create a hum problem of its own.
Arthur