Easiest way to isolate the DAC from the noisy PC?

[Katji]

I don’t hear any noise but for example when I touch the cable that is used to connect my keyboard and pc, I can hear crackling through my headphones and that type of things...

I only hear crackle when I am inserting my keyboard or other device into port. After inserting it is ok

Is that a typical ground loop issue or is it a typical of faulty connection/cable?

 

[Windofrce]

typical ground loop issue

Why I don't hear anything when I am listening to music, even with onboard audio (ALC 1220)? 100% silent.
I only hear when connecting or disconnecting things from the PC, when cable which goes into the keyboard touch the metal part of USB C connector before it goes in?

 

[Windofrce]

Hey guys. I tested for ground loop by plugging in my very low impedance IEMs into AMP, playing silent tone and turning amp volume to max. Zero noise in this case. Does it mean that I don't have ground loop? Thanks

 

[shrimp_dude]

In the past I used to have major issues with hearing noise from GPU and power supply, most noticeably when moving the mouse. Using a USB isolator like the idefender3 solved the issue. Don't have the issue anymore however after I upgraded the pc a while back.

 

[192kbps]

typical ground loop issue

I read all your replies, Are these the solutions to noise?

Toslink/XLR Input/USB Isolator/Linear Power/Wall Outlet/Short RCA cable/Ferrite Core

 

[JohnYang1997]

I read all your replies, Are these the solutions to noise?

Toslink/XLR Input/USB Isolator/Linear Power/Wall Outlet/Short RCA cable/Ferrite Core

usb isolator

 

[Windofrce]

Do you guys know what can be an issue when I am changing volume level using AMP potentiometer, I can hear crackle not in all range but in a few spots, even if I reduce DAC volume digitally through windows. Problems, problems..

 

[AnalogSteph]

Test whether it still does that when the DAC connection is unplugged. Might be output DC offset, though it would take a fair bit, so I kind of doubt that.

Otherwise it could simply be a noisy pot and/or slightly leaky coupling caps in the amp, not much you can do about as a user.

What did your bass test tone testing reveal, btw? I still think it's USB hiccup. Well, either that, or the DAC's effective power supply rejection is really going south towards the higher frequencies, or it momentarily drops out of regulation, i.e. the plug/unplug events are causing a larger spike than it can handle. In which case the powered USB hub would be worth a shot.

 

[Windofrce]

I just tried my AMP / DAC setup on a laptop and guess what?! The scratching during the volume change is gone! What can you suggest to me now? That is one really old laptop btw.. but as we can see my high end pc is causing problems. It is completely silent during listening, no ground loop noise or anything, but there is scratching during volume change

 

[Zek]

but there is scratching during volume change

Volume pot need some cleaning.

 

[Windofrce]

Volume pot need some cleaning.

Digital crackling not scratching.

 

[Tim6622]

Hi,

I have Khadas Tone Board DAC and very noisy USB ports. I would like to know what is the easiest way to bypass powering the DAC from PC usb ports.
What if I buy high quality USB hub with it's own power adapter and power DAC by that?

I've had noise on my usb port once when gpu was in use. A fix I came across was putting tape on the ground pin in the usb male connector so it would not make contact. It eliminated EMI from the main board leaking to usb port controllers

 

[bogi]

I've had noise on my usb port once when gpu was in use. A fix I came across was putting tape on the ground pin in the usb male connector so it would not make contact. It eliminated EMI from the main board leaking to usb port controllers

Your example shows that computer generated noise (not ground loop) may audibly affect DAC performance.
The computer USB signal consists of VBUS (+5V), ground, DATA+ and DATA-. Before the playback starts, protocol handshake between computer USB audio driver and USB receiver in DAC takes place and this handshake requires both devices to use common ground. It seems after disconnecting USB ground you are getting ground related to computer through power cables (or maybe through computer monitor digital cable and then AMP or DAC power cables) and that ground is not so much polluted by noise as the computer USB port ground.

 

[ReinhardS]

An CM6631A or XMOS asynchron USB-Audio-Interface (with separate Power Supply at best) and an optical Toslink Cable to a separate DAC. I think this is a easy but good enough way.

 

[Windofrce]

I think I will use it as it is. I can only hear it when using volume knob and desktop PC. For me it is important that it is not audible during sound reproduction...

 

[manueljenkin]

Something like this? https://www.loligosystems.com/usb-20-isolator-fullspeed

Optically isolated and fast enough for audio. If you search other shops, you can find the same product for cheaper (around 50 USD ish)

 

[theglobalelite]

I've seen a few posts on here that said the iFi iDefender is good for breaking group loops: https://www.audiosciencereview.com/...se-filtering-product.12695/page-4#post-512243

It's supposed to be not snake oil like other iFi "purifier" gadgets: