To get ride of PC white noise, dac with balanced outputs or dac with optical input ?

[jpqc]

ok so for the record, if that can help anybody eventually ...

I tried a few things (that did not work) to eliminate the remaining noise completely
- tried another wired mouse
- tried a wireless mouse
- tried plugging my monitor to another power outlet (was previously plugged in my Cyberpower APC)
- tried disabling pc microphone inputs
- tried disabling gsync on monitor

using topping dxpro :
- tried using bluetooth + tried optical input + tried usb input
- tried using RCA to TRS cables instead of 3.5mm to TRS 6.35

things that worked :
- using dxpro bluetooth with usb input cable unplugged
- using dxpro optical input with usb input cable unplugged
- using HDMI for monitor instead of Display Port (for reference my monitor is DELL S2716G) ... noise is reduced by 95% but I lose gsync and 144mhz refresh rate

some observations :
- lowering the volume on the JBL speakers to about 70% reduces the noise by about 50%
- noise go away when I unplug my monitor (either display port or power)
- noise is not related to mouse but to what is shown on my monitor
- either noise comes from monitor or from gpu (or cpu?)

todo :
- try another monitor
- try another display port cable

 

[Lambda]

- using dxpro bluetooth with both optical and usb cables unplugged

Wait you are having the usb cable Connected before?!
whats the point of having isolated optical cabel if you leaf the USB cable connected?

todo :
- try another monitor
- try another display port cable

sounds like your doing this very non systematical and punting a lot of effort (money) in despite there have been many trouble shooting tips.
And solutions.

- either noise comes from monitor or from gpu (or cpu?)

Noise comes from the current going trough your Mainbaords ground plane. so GPU and CPU power mostly.

- lowering the volume on the JBL speakers to about 70% reduces the noise by about 50%

No surprise but % dose not actually make sense if you talk about volume/gain.
in dB the noise is reduced the same amount as you reduce the input gain.

How did you even set the input gain/sensitivity up?

 

[jpqc]

Wait you are having the usb cable Connected before?!
whats the point of having isolated optical cabel if you leaf the USB cable connected?


sounds like your doing this very non systematical and punting a lot of effort (money) in despite there have been many trouble shooting tips.
And solutions.


Noise comes from the current going trough your Mainbaords ground plane. so GPU and CPU power mostly.


No surprise but % dose not actually make sense if you talk about volume/gain.
in dB the noise is reduced the same amount as you reduce the input gain.

How did you even set the input gain/sensitivity up?

About the usb cable, I tried the optical in while leaving the usb in, I tought the dxpro would be smart enough to "ignore" noise coming from usb when optical input is selected but it seems it does not.

About the solutions, at this point, I have some but I'm curious about finding the root cause
Probably ground noise but I was surprised unplugging my monitor fixed it.

 

[Lambda]

I tought the dxpro would be smart enough to "ignore" noise coming from usb when optical input is selected but it seems it does not.

That's as you learnd not how it works.
Reed about "ground loops" and "galvanic isolation" there is a lot of information about it on wikipedia and in this forum.

About the solutions, at this point, I have some but I'm curious about finding the root cause

That’s obvious.
If current flows trough some conductor there is voltage drop depending on current and impedance.
GPUs CPUs can pull many 10s of Amps so what is supposed to be ground is no longer at ground level. (USB ports and analog out)
Normally the cases and IO shied provide an extra low impedance GND for thing like USB ports but not if everything is painted...

The other thing is every current loop makes an magnetic filed an vice versa. Plexiglas is not stopping theme.
Your speakers are Grounded to PE and so is your PC this is the classic ground loop.

Probably ground noise but I was surprised unplugging my monitor fixed it.

Well the GPU is pulling the most power in most PCs.
If you remove the antenna (the cable) from it, it can't transmit the noise as well and it is probably smart enough to stop doing it’s thing if it detects that there is no monitor.

Your not the first one having this problem.
This is super common. especially with your configuration this is almost expected.

 

[AnalogSteph]

I’m not sure whats the cheapest useful way to get balanced and isolated.

The trusty Behringer HD400 is like 26€ here, plus cables (stereo 3.5 mm or dual RCA to 2x 1/4" TS in, 2 pcs. 1/4" TRS to XLR out) we're somewhere in the 40s depending on how much fancier than the absolute cheapest cables you want to get (which you won't be surprised to hear may have their build quality issues).