Think iv got ground loop problems

Thread Starter

jmh474

Joined Jun 26, 2014
38
So I'm retro fitting a xbox 360 with a raspberry pi 3b+, I'm planning on running multiple os with the pie.

Iv connected my pie to a amplifier in the 360 housing and its picking up all sorts of noise. The amplifier is picking up every little bit of noise from everything and it's horrible.

Iv got a single 12v power supply power running everything 12v to the sata to usb to run the hdd and the 5v from the pie, 12v to the twin fan the original xbox fan, 12v feeding the amplifier, 12v to 5v feeding the pie and 12v feeding a few leds.

If I was to isolate the amplifier on its own power supply and have a ground loop isolate from the pie to the amplifier would this rid me of the noise.

The noise only appears when the pie is plugged into the amplifier via 3.5mm jack.

Or dose anyone have any other ideas as not really got the room for an additional power supply.

Thanks for any help
 

KeithWalker

Joined Jul 10, 2017
1,511
So I'm retro fitting a xbox 360 with a raspberry pi 3b+, I'm planning on running multiple os with the pie.

Iv connected my pie to a amplifier in the 360 housing and its picking up all sorts of noise. The amplifier is picking up every little bit of noise from everything and it's horrible.

Iv got a single 12v power supply power running everything 12v to the sata to usb to run the hdd and the 5v from the pie, 12v to the twin fan the original xbox fan, 12v feeding the amplifier, 12v to 5v feeding the pie and 12v feeding a few leds.

If I was to isolate the amplifier on its own power supply and have a ground loop isolate from the pie to the amplifier would this rid me of the noise.

The noise only appears when the pie is plugged into the amplifier via 3.5mm jack.

Or dose anyone have any other ideas as not really got the room for an additional power supply.

Thanks for any help
Can you supply a simple diagram showing how you connect the power and wiring between the different devices? It would make it much easier to understand your problem and to help you.
 

Sensacell

Joined Jun 19, 2012
2,718
Tricky problem, digital systems (like the Raspberry Pi) draw large supply currents, rich with nasty noise frequencies.

1) Improve the ground configuration - super short and robust - a 'star' ground with short and heavy wires.
2) use a 1:1 audio isolation transformer between Pi and amp.
 

KeithWalker

Joined Jul 10, 2017
1,511
Just powering up no os loaded
With nothing running on the Pie, the output pins are floating. You have a high gain amp connected with no volume control so you are hearing the static charge on the output. Try loading a simple audio program (music or something like that) and see how it sounds then.
 

Thread Starter

jmh474

Joined Jun 26, 2014
38
It's not really the pi I'm getting feed back from its the hdd and twin fans that's making the noise
 

KeithWalker

Joined Jul 10, 2017
1,511
It's not really the pi I'm getting feed back from its the hdd and twin fans that's making the noise
The amplifier input is connected to the audio output of the Pie I presume - not to the HDD or fans. As I mentioned above, with no program running on the Pie, it's output is floating and it will pick up every bit of electrical noise generated anywhere in your system which will be amplified by your amplifier. You can either load an audio program on the Pie and see how it works or you can chase phantom noise until you damage something.
 
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