Easiest way to isolate the DAC from the noisy PC?

[Windofrce]

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?

 

[Jose Hidalgo]

What is the problem in having noisy USB ports ? USB is digital, not analog. The audio will be transmitted anyway, and the transmission will be lossless. What more could you expect ?

 

[AnalogSteph]

Why do you think you have "very noisy USB ports" in the first place?

I won't be one bit surprised if this one turns out to be a ground loop, but we'd have to know the other components to be sure.

 

[A800]

Get something like this.
https://www.amazon.com/Nobsound-Audio-Eliminator-Industrial-Protection/dp/B07GB4CQQ3

 

[Windofrce]

What is the problem in having noisy USB ports ? USB is digital, not analog. The audio will be transmitted anyway, and the transmission will be lossless. What more could you expect ?

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...

 

[Jinjuku]

Have you tried another USB cable? What is the computer? You can get a wireless mouse and KB for $22.

 

[Windofrce]

Have you tried another USB cable? What is the computer? You can get a wireless mouse and KB for $22.

If I don’t want wireless keyboard how can I avoid this issue? Not pissible? Why is it happening?
I have high quality PC components including usb 3.1 and type c ports and titanium Corsair power supply. Cables are also high quality.

 

[Windofrce]

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

 

[Ron Texas]

Toslink?

 

[AnalogSteph]

OP, what's your audio gear attached to the Tone Board?

I have high quality PC components including usb 3.1 and type c ports and titanium Corsair power supply. Cables are also high quality.

The part that is most likely to be problematic in modern PCs is the case. When they were bare metal inside you could be pretty sure that they'd do a decent job making contact everywhere, but today where everything is painted and there are windows in the sides, all bets are off. Nobody ever does RF emissions testing on PC cases only sold to consumers, quite unlike the kind of scrutiny that pre-assembled machines from major manufacturers will undergo.

Still, it doesn't even have to be the PC itself that's the problem. My bets would still be on an external ground loop that happens to be comprising the USB power ground connection.

 

[Windofrce]

OP, what's your audio gear attached to the Tone Board?

The part that is most likely to be problematic in modern PCs is the case. When they were bare metal inside you could be pretty sure that they'd do a decent job making contact everywhere, but today where everything is painted and there are windows in the sides, all bets are off. Nobody ever does RF emissions testing on PC cases only sold to consumers, quite unlike the kind of scrutiny that pre-assembled machines from major manufacturers will undergo.

Still, it doesn't even have to be the PC itself that's the problem. My bets would still be on an external ground loop that happens to be comprising the USB power ground connection.

Tone board is connected to JDS Labs Atom AMP. I am using that combo to drive Beyerdynamic DT990 Pro 250 ohm. How can I be sure that it is ground loop? I don't hear anything while playing or idle, only when connecting new things to my PC..

 

[Chrispy]

If it only happens when you jiggle connections seems something is off in the cables/connection points rather than a particular issue otherwise. Stop jiggling the wires when you listen....

 

[Atanasi]

Tone board is connected to JDS Labs Atom AMP. I am using that combo to drive Beyerdynamic DT990 Pro 250 ohm. How can I be sure that it is ground loop? I don't hear anything while playing or idle, only when connecting new things to my PC..

If you don't have those connected to anything else, there shouldn't be a ground loop. I had a ground loop with Atom when connecting both inputs.

 

[JeffGB]

The simplest and most effective way to isolate from the PC is to use the optical connection and connect your USB power cable to a small USB power adapter. I'm using one for an iPhone. In this case, since you don't have a problem unless you insert the jack or move it perhaps a better cable would help. I have a Creative G6 set up this way. I had intermittent noise still and replacing the 3.5mm to RCA cable fixed it.

 

[Chrispy]

The simplest and most effective way to isolate from the PC is to use the optical connection and connect your USB power cable to a small USB power adapter. I'm using one for an iPhone. In this case, since you don't have a problem unless you insert the jack or move it perhaps a better cable would help. I have a Creative G6 set up this way. I had intermittent noise still and replacing the 3.5mm to RCA cable fixed it.

Khadas Tone Board doesn't have optical input, tho....

 

[Jose Hidalgo]

Sell Khadas Tone Board. Buy Topping D10s or E30 for about the same price. Add an optic cable. Problem solved.
If you can afford a high-end computer rig, surely you can afford some more $/€ (the difference between selling the KTB and buying a D10s/E30).

 

[AnalogSteph]

Tone board is connected to JDS Labs Atom AMP. I am using that combo to drive Beyerdynamic DT990 Pro 250 ohm. How can I be sure that it is ground loop? I don't hear anything while playing or idle, only when connecting new things to my PC..

Weird. A lone Y capacitor (single-digit nF range) in the Atom's power supply aside, there is very little potential for ground loops. You do not happen to live in a very dry climate by any chance? If so, does just touching the PC case do something similar?

OK, sanity check time - what is master volume on the PC set to? If below 50-80% (-10..-3 dB), increase to this range, and reduce volume (and if needed, gain) on the Atom correspondingly..

With that out of the way, I would want to test whether it is an analog problem or in fact an interruption of the audio data stream.
Would you mind generating a low-frequency sine (like 50 Hz or something - the tone generator function in Audacity is perfectly fine), playing that back and then plugging/unplugging your keyboard or mouse?
If it is a purely analog problem, the crackling would be equally loud as without the test tone.
If it is a problem on the digital side, playback of the test tone may turn the crackles into major cracking noises.

Also, try a USB output in a different location to see whether the issue occurs everywhere. Ports at the back should generally be the safest, and USB3-capable ones may be more robust in terms of power delivery than purely USB2 ones. Long, thin cables to a front port may cause momentary dropouts as things are plugged in.

To rule out that momentary power loss is causing the issue, you can try running the DAC via a powered USB hub.

Download and run the tool LatencyMon to make sure DPC latency is within reasonable limits.

If nothing else helps, I would try another DAC... possibly via Toslink as suggested, assuming your board has an optical output. (Note: D10s has an optical output only, E30 has an input.)
Speaking of which, have you tried the onboard audio yet? A higher-end board may be using a Realtek ALC1220, which actually is pretty good if the implementation isn't screwed up by the board manufacturer. Achievable dynamic range is as good as any low/midrange DAC, just distortion performance doesn't make it much beyond -90 dB, but that's still inaudible.

 

[datrumole]

i went around in circles in your situation, for me the biggest offender was HDD noise. anytime my ssd did anything, noise on the line. i have a UDAC8 and went through every f'in solution i could think of. i modded the USB cable to drop the ground line (power is given to that unit in a separate adapter), i tried it on multiple computers in my home where i have a wide ranging set of MB and Gold/Platinum power supplies. all the same noise

what finally shut the thing up, was using a different socket on my modular power supply for my HDD SATA power adapter. noise gone. so weird

basically you're going to have to try and find something that works for you, a lot of good suggestions here, so you may have to try a few. you can maybe try and play with a plain old wire, screw it to the computer chassis, or heck even try somewhere on the mobo IO area, and run the other end to the USB dac, again jsut try and touch things until the noise gets worse or better. the isolators noted in the very early comments (i have one but never hooked it up as i fixed mine before i took delivery of it) should work too, but they are bandwidth limited in case you are using something higher end

 

[Jinjuku]

If I don’t want wireless keyboard how can I avoid this issue?

Is there a reason you don't want a wireless KB/Mouse? What would happen if it fixed the issue?

 

[JohnYang1997]

typical ground loop issue