Audio Ground Loop Issue

[chessiv]

I'm running a pc in a cab and am using a 35 watt audio amp that requires 12v. I used the computer power for the 12v and had no problems. I switched computers out and heard lots of "computer noise" moving the mouse causes a noise. When the hard drive runs you can hear a noise. I think I've tracked the issue down to differences in the power supplies. I've tried running the amp from a seperate computer power supply and sometimes the noise goes away sometimes it doesnt. Is there a way to still power the amp from the computer and eliminate this noise?

The hookup is 1/4" from the line out of the computer audio (integrated realtek) to the amp.

Thanks

[ami-man]

Hello,

I would use a self contained power supply that can supply 12 volts at around 5 amp plus.
Most electronic suppliers should have some form of bench power supply.

Regards
Alan Hood
ami-man

[crzywolf]

Have you tried using a "Ground loop Isolator" ?

[bigvic]

 l never like to power anything from a computer power supply especially and amp because it will amplify any  noise problems, it was explained to me some time ago that computer power supplies are not always suitable because they are swithing or switch mode supplies whatever that means. Anyway the simplist and safest way of doing it l think is to buy a 12 v transformer  throw a small bridge retifier on it and there u have a 12dc output, just make sure you get one big enough to handle the current requirements of your amp. If you need filtering then u will require a 9v tapped transformer, and with the filtering cap it will be retified to 12 dc output.

Run the 240v to the primary of the transformer from the main incoming 240v, and don't forget to earth things.