Computer case has a separate ground that seems to be causing some noise.

Discussion in 'Computer Audio' started by 78_towncar_460, Jun 5, 2018.
  1. 78_towncar_460
    I have a computer case (Antec 900) that I occasionally use the front panel headphone jack (3.5mm or 1/8" TRS style). This is an older computer case and has two USB 2.0 inputs, a firewire input, and then a microphone and headphone jack. I was prepared to replace the old USB module with an updated USB3.1 module from the manufacturer, but decided not to....however, upon disassembly of the case, I noticed that there was a ground wire coming off of the front panel module which was screwed to the metal case.

    Now, the USB connections have their own ground to the motherboard as does the firewire port. Is it normal for a headphone or microphone jack to have a separate chassis ground? I am wondering because this is a fairly noisy headphone jack (electrical noise). When the ground wire is removed, there is no noise through the headphones. The power switch, reset, and LED hard drive activity light have their own separate wiring. As far as I know, a standard TRS jack has ground at the base of the jack and that wire runs as one of three wires inside the insulation of the headphones.

    What would this separate case chassis ground be for? I imagine it has to be for the audio jacks. I was told by the manufacturer to remove it, but it has to be there for a purpose.....the only thing I can think of is that since there is only one ground inside the front panel audio connector to the motherboard, it is just a second ground. Is it safe to remove?
     

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