Puritan Audio Route Master
The signal grounds on your various Hi-Fi and AV Components may conform to any of a number of practices: At the original and basic level that manufacturers still adhere to, chassis ground is the same as safety ground, is the same as signal ground. But on some equipment chassis ground does not equal safetly ground and on much equipment signal ground is lifted from chassis ground. Of course connecting, say via RCA an item where the three grounds are unified to a component where they are not, will result in that second component having its signal ground united with safety ground etc. And through the interconnection of all signal leads a haphazard confusion of circulating signal grounds is created.