[tony brady]

I design audio in the day job to CE and CQC ( China) regulations. I would like to be very clear on this point NEVER remove the mains earth from the chassis of a class 1 unit and replace by anti parallel diodes or combinations of a resistor and capacitor. It is perfectly acceptable to lift the AUDIO ground from the chassis and use diodes or say a 10 ohm fusible in parallel with 100nF while maintaining the earth bond to the chassis.

for CE we test the earth bond at 25A for 5 seconds at less than 100 milli ohms. For CQC it is 25A at less than 100 milli ohms for 60 seconds. this includes the lead from the test gear to the unit under test