Audio project, ground loop question

Discussion in 'The Projects Forum' started by subXero, Jul 29, 2009.

  1. subXero

    Thread Starter New Member

    Jul 29, 2009

    So here is a break down, I put together an audio system for research was not getting enough output from my speakers, so purchased an amp, and power supply to run the amp and presto good output and lots of noise.

    I know DC power supplies can introduce a fair amount of noise into the signal and that is a possible source of my problem, but overlooking that for the moment and getting to my main question about a ground scheme.

    So even if the power supply it's self is my main problem i still believe i have a ground loop and want to try and get my set up to a single point ground but need clarification on a few points.

    1) basic run down of set up

    PC with NI PCI card provides 2 signals to amp via BNC cables
    PC is grounded via 3 prong plug to outlet

    DC power supply powers car audio amp, positive terminal of PS to +12v on amp and neutral to the GND on the amp
    PS grounded via 3 prong plug to outlet

    From amp, speakers wires run to 2 speakers. amp grounded to PS neutral

    The neutral of the power supply is likely grounded to its case and then run to earth via plug....right?

    PC case grounded to earth via plug, (all BNC cables grounded to case and amp,

    amp grounded to neutral of PS, (BNC's grounded to amp & PC)

    So here are the questions,

    Is neutral the same as ground on the DC PS, I know the neutral lead comes out of the center of the transformer but pretty sure it is the ground?

    Could I eliminate plug grounds then take all case grounds to a star ground, then take star ground to earth?

    Is there a better way?

    And info greatly appreciated.

    Thanks in advance
  2. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    What brand / model amp did you buy?
  3. subXero

    Thread Starter New Member

    Jul 29, 2009
    arc audio mini 125.4, only amp i could find with a frequency range up to 50khz which is important for our system.
  4. subXero

    Thread Starter New Member

    Jul 29, 2009
    PS is a pyramid 46kx, i know the noise on it is bad but like i said in the post, taking it one step at a time, looking to fix a possible ground loop before i replace the PS.
  5. flat5

    Active Member

    Nov 13, 2008
    You might use an ohm meter to verify your assumptions about the grounding. Get those questions out of the way.
    Exactly what noise do you hear? Care to provide an mp3 if hard to describe?
    Last edited: Jul 30, 2009
  6. subXero

    Thread Starter New Member

    Jul 29, 2009
    Noise is not in human audible range and is picked up by sensitive microphone from speakers and seen on software. But yeah, definitely need to meter some stuff and get things worked out.