Interference noise on home-built PC

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Athlonite

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#1325231 15-Jun-2015 18:13

How is the mobo attached to the mobo tray in the case which of these does it use

antoniosk

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#1325386 15-Jun-2015 22:27

Athlonite: How is the mobo attached to the mobo tray in the case which of these does it use

Brass ones of course - haven't seen plastic ones in ages....

This is my first gigabyte mobo, have always used asus in past.

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#1325770 16-Jun-2015 13:55

Ok so grounding for the motherboard is not the issue which leaves the PSU I'm afraid, are you able to try another PSU either the same type/manufacturer/wattage or one from another manufacturer

richms

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#1325866 16-Jun-2015 15:47

It's not going to help. It's noise from the other devices on the motherboard. Impedance of the PSU leads means that no amount of filtering in the psu will solve the noise.

The designers of the motherboard would have not had any concern about low level noise on the audio outputs. It's a few cents of bits on the motherboard to tick a box.

If you want clean audio then either buy a card or proper usb device or else use the optical out into a standalone DAC to get around any noise on the pc power.

Richard rich.ms

antoniosk

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#1326045 16-Jun-2015 20:03

richms: It's not going to help. It's noise from the other devices on the motherboard. Impedance of the PSU leads means that no amount of filtering in the psu will solve the noise.

The designers of the motherboard would have not had any concern about low level noise on the audio outputs. It's a few cents of bits on the motherboard to tick a box.

If you want clean audio then either buy a card or proper usb device or else use the optical out into a standalone DAC to get around any noise on the pc power.

I was thinking of that... Deal extreme.....

________

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#1328619 21-Jun-2015 11:37

richms: It's not going to help. It's noise from the other devices on the motherboard. Impedance of the PSU leads means that no amount of filtering in the psu will solve the noise.

The designers of the motherboard would have not had any concern about low level noise on the audio outputs. It's a few cents of bits on the motherboard to tick a box.

If you want clean audio then either buy a card or proper usb device or else use the optical out into a standalone DAC to get around any noise on the pc power.

Interestingly, I have connected the USB cable (its only used for power) to an external quality point (an iphone charger), and there is no noise in the speakers. I'm really suspicious of the wires used to connect the USB ports in the case now....

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ubergeeknz

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#1329167 22-Jun-2015 12:18

So it is your speakers, not the motherboard?

I guess you can call it "problem solved"...

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antoniosk

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#1329184 22-Jun-2015 12:30

ubergeeknz: So it is your speakers, not the motherboard?

I guess you can call it "problem solved"...

Don't know. I've never used PC USB powered audio in the past, only the audio connections. The fact that the Monitor does pick up the feedback, and is only connected via DVI and Analog audio suggests to me there is something going on at board level.

Nonetheless... problem kinda worked around.

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#1329247 22-Jun-2015 13:19

antoniosk:
ubergeeknz: So it is your speakers, not the motherboard?

I guess you can call it "problem solved"...

Don't know. I've never used PC USB powered audio in the past, only the audio connections. The fact that the Monitor does pick up the feedback, and is only connected via DVI and Analog audio suggests to me there is something going on at board level.

Nonetheless... problem kinda worked around.

Same analog cable?

antoniosk

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#1329250 22-Jun-2015 13:25

ubergeeknz:
antoniosk:
ubergeeknz: So it is your speakers, not the motherboard?

I guess you can call it "problem solved"...

Don't know. I've never used PC USB powered audio in the past, only the audio connections. The fact that the Monitor does pick up the feedback, and is only connected via DVI and Analog audio suggests to me there is something going on at board level.

Nonetheless... problem kinda worked around.

Same analog cable?

nope

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ubergeeknz

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#1329254 22-Jun-2015 13:28

Bit weird then but possibly some kind of ground loop/floating ground issue

richms

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#1329339 22-Jun-2015 15:19

It will be. Speakers are grounded to the PC back thru the USB cable, Monitor is thru the displayport/dvi/whatever cable shield.

When on the cellphone charger then its isolated from the PC earth so no ground loop happens. There will be a ground difference between the audio socket and the other sockets making the loop happen, inducing the noise to the speakers.

Richard rich.ms

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