Fully floating signal ground from chassis/PE is dangerous because some stray charge and leakage current potential is generated between them and it's easy to get a person between the differently charged points.
10R bleeds eliminate this charge and in the rare (but possible) case of an insulation failure from mains line to chassis before (upstream of) the line fuse will try to trip the house breaker. Current practice is to parallel the 10R with large back-to-back diodes, sometimes two in series in a bridge, to increase survivability (must live long enough to trip a house breaker).
Considering signal return currents, we should also remember that ordinary stereo connections have two (minimum, with PE issues resolved) identical current return paths, and that each channel's return current travels half through its nominal "ground" path and half through the other channel's. Immunity to external noise sources requires equal and opposite signal "hot" and "return" currents in each conductor pair (coax or twisted pair) to work right, and we violate that for ordinary stereo interconnections.
Fortunately we can, usually, get away with it at home. But it's not nearly ideal. 10R isolations of each channel from the other is the next step.
All good fortune,
Chris
10R bleeds eliminate this charge and in the rare (but possible) case of an insulation failure from mains line to chassis before (upstream of) the line fuse will try to trip the house breaker. Current practice is to parallel the 10R with large back-to-back diodes, sometimes two in series in a bridge, to increase survivability (must live long enough to trip a house breaker).
Considering signal return currents, we should also remember that ordinary stereo connections have two (minimum, with PE issues resolved) identical current return paths, and that each channel's return current travels half through its nominal "ground" path and half through the other channel's. Immunity to external noise sources requires equal and opposite signal "hot" and "return" currents in each conductor pair (coax or twisted pair) to work right, and we violate that for ordinary stereo interconnections.
Fortunately we can, usually, get away with it at home. But it's not nearly ideal. 10R isolations of each channel from the other is the next step.
All good fortune,
Chris
