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Does my laptop need to be grounded when charging?

I generally leave my MacBook Pro attached to its charger while listening to music files played thru my dac via USB.  I have noticed that when I am barefoot and gently rub my finger over the metal surfaces of the laptop that I feel a slight fuzziness as if there is stray voltage going through me.  It is not a shock per se and the sensation goes away when the charger is unplugged.  The charger does not have a ground prong. Should I ground the metal cover of the laptop? Should I get into the habit of disconnecting the charger when I listen to music files from the laptop?  Is this normal?
jc4659
erik_squires
16,041 posts
 
I don't know if it's normal, but the noise and ground loops of the charger have been well documented. If your DAC does not already include a USB galvanic isolator, it's a good idea to use one. They can be cheap, like $30
jc4659 OP
549 posts
 
Thank you, Erik.  Yes, my dac already employs "galvanic isolation to the outputs" but not really sure if this means I shouldn't be concerned about noise coming into the dac.  Some of these isolators are inexpensive while others such as the Intona or ISO Regen are >$300.  I am currently using a codex.
jea48
4,415 posts
 
@jc4659
Is the AC plug on the charger polarized? If not try reversing it 180 in the wall outlet and see if that helps.
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