Phil Allison wrote:
"Serge Auckland"

Sensible advice, but isn't it a pity that consumer electronics rarely
follow professional practice of having a permanent safety ground, and a
separate audio ground which can be bonded to safety ground or lifted.



** Shame how in very case where that is seen it is VERY unsafe !!

Floating the internal circuitry while grounding the external metalwork of AC
powered audio gear is a recipe for a FATAL accident.

Think it trough.

Humans touch the connectors that link to that floating circuitry.




....... Phil




Don't understand the problem. The metal case is permanently connected to
the safety ground. The power supply transformer laminations are also
grounded to the case. The transformer secondary floats, as does all the
audio circuitry. No different to double-insulated appliances where
nothing is grounded. With SMPS, the isolation is done at high switching
frequencies rather than mains frequencies, but in the same way. I have
never come across a problem with lifting the audio ground in pro gear.

S.