Transformer's Center Tap Connection


2011-11-25 9:16 pm
My chassis ground and signal ground are NOT connected with each other. The chassis is only connected to ground pin on the IEC.

Signal ground is in a star configuration and this is the spot where the transformer's center tap of the secondaries is connected to.

Should I connect this star ground point with a wire to the neutral pin on the IEC socket?

Otherwise I see three potential ground points:

1.) Transformer's primary at the neutral IEC pin.
2.) Floating signal ground's star configuration point on the circuit board.
3.) Chassis' ground point to the ground IEC pin.
But what if I want to keep the chassis and signal ground separate?

Put a switch in.

I found with an MP3 player I needed the earth connected and when connected to a cd player or PC it wasn't needed and sometimes caused hum.

There are a few ways to get around the direct connection to earth.
Sometimes people use a capacitor to short out the noise to ground.
I have seen back to back diodes used too.
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