Here's the stupid question: ... What would happen if you "simply [broke] the chassis to chassis shield connection" in an effort to eliminate interchassis ground current?Hi Bryon,
That isn't a stupid question. The answer is that you would also be breaking the signal return path. Keep in mind that electricity only flows if there is a complete circuit, from source to destination and back.
If you were to break that return path in the interconnect cable, and both components had 3-prong power plugs, the return path that would be taken would be through the ac safety ground wiring of the power cords, and whatever additional safety ground wiring would be necessary to reach a ground point that is common to both components. That would result in noise problems.
If either or both of the components had a 2-prong power plug, and no other ground path existed in the system between the components, then the destination component would see a "floating" input voltage (i.e., one that is not referenced to its own ground). That would result in uncontrolled behavior, and very conceivably in full-power noise levels that could damage the speakers.
Best regards,
-- Al