[tw_switzerland]

Hello

I have a question I did not find an answer for:

What is the function of the third ground pin on the external switching power supplies? E.g. like the ones used for most Tripath amps.

I saw that there are power supplies having two pin connectors only, and others (most) do have 3-pin-connector with earth/ground.

As the case is plastic, it doesn't have to be connected to ground. And the amp itself is not connected to the earth pin at all. So I think one reason for ground could be filtering out the noise? Or am I totaly wrong?

And are the ones without ground as goog as the others?

Thanks!
Thomas 

[Speedskater]

The one's with two pin connectors have to pass further safety tests by an authorized agency (UL/CSA in N. America). So making a good case that will pass the test may cost more than the 3 pin plug.