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Ground loop issue... with an audio cable?

auxgroundloop

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I'm using a DAC/amp combo (one single unit) that's connected directly to my PC with a USB cable that carries both data and power. Everything is fine when I use regular AUX cables, but problems arise when I use a cable that uses an interconnect. The current setup looks like this:

[DAC/Amp] to [3.5mm male to 4 pin mini XLR male] to [4 pin mini XLR female to 3.5mm male] to headphones, interconnect is bolded

When I use this setup, I run into issues that the DAC/Amp maker identified as a ground loop based on the symptoms:
-I hear electrical pop noises when moving the cable
-Positioning the cable in certain angles and squeezing it can cause really loud, continuous static noise
-the DAC/amp heats up and gets MUCH hotter than it normally does compared to when I use another aux cable

From what I've read, ground loops are caused by stuff like power sources being separated, but I don't get how that can apply to my situation when it's a single unit that's connected to my PC with a single USB cable.

Any help would be appreciated!

Edit: It's probably not a ground loop issue after all - I got in contact with the company that makes the cables and they basically admitted fault and said it was because the cables don't have some kind of "shielding" that is necessary in my situation.

Still looking for possible solutions on my end though
 
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twsecrest

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Try connecting the DAC/amp and PC to separate surge protectors.
 
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auxgroundloop

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Try connecting the DAC/amp and PC to separate surge protectors.
The DAC/amp is a single device that only takes a single USB cable. It must plug into the PC through USB. I tried a different cable, but nothing changed
 

solderdude

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There is no ground loop here. There cannot be.

Best guess would be poor connection somewhere.

It seems like the 'Aux' cable is a headphone cable and that this cable with the XLR-4 conversion either somehow destabilizes your amplifier or shorts it when you hear crackling noises (when it truly gets hotter than with a normal cable).

Return the cable and get a replacement when the original cable works fine.

Maybe its the way you name cables that is confusing.
An Aux cable usually refers to an RCA to RCA cable connecting a DAC RCA out to amp input for instance.
An interconnect actually means the same but could also be balances where RCA cables are not.
What I get from your story is:
PC-> DAC/amp (without external power supply) -> headphone.
 
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auxgroundloop

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@solderdude Sorry for my ignorance in terminology. By aux cable, I meant just a regular 3.5mm to 3.5mm cable that connects the DAC/amp to the headphones. Those work fine without issue.

Anyways, I got in contact with the company that makes the cables and they basically admitted fault and said it was because the cables don't have some kind of "shielding" that is necessary in my situation. Still awaiting further contact for more info, but it does not seem like a ground loop issue after all.

But I do have a second cable from the same company that is just a basic 3.5mm to 3.5mm which also produces the same issues, so the interconnect is irrelevant.

I'm not sure what kind of "shielding" is missing here, but they offered to send me replacement cables with the "shielding" added which is supposed to fix the noise issue. However, the cables will be stiffer and thicker, which defeats the purpose of why I paid so much for them in the first place - I really liked how soft and flexible they are.

Does anyone have any knowledge about this "cable shielding" topic, and how to fix my problems without it? What I don't get is that the company, while small, seems to not include the shielding by default, yet (I assume) their many other customers don't have issues. I feel like a special case, and I wonder if it's something I'm doing wrong.

And to be very clear, my current setup is:

(PC plugged into power) -> (USB A to C cable) -> (DAC/amp) -> (3.5mm to 3.5mm cable) -> (Headphones)

The (DAC/amp) takes in exactly one USB cable with data and power, and then outputs to one 3.5mm jack.
The whole interconnect thing is irrelevant now, since I am experiencing the same issues with a basic 3.5mm to 3.5mm cable that's missing this "shielding"
 

tonycollinet

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Is there no external power for the Dac/Amp? If not, does the USB provide enough power to power the amp and the headphones?

Pop noises when moving the cable is not a ground loop, as pointed out above that sounds more like a bad connection. As does loud "static" when squeezing.

If this is happening with two entirely different wires, then I'd be suspecting the 3.5mm connector in the DacAmp.
 

tomtoo

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This 3,5mm cabels are a pest. At least in my experience. You can get completly different shilding quality. And on top of this comes contact quality of the jacks. I know its a rant, but i learned to hate them. They are ok to connect something passive after them, like a headphone. But if come a gain stage after them, its some kind of good luck.
 
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auxgroundloop

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@tonycollinet The problem is happening with 2 different cables from the same company that makes their cables without this "shielding" by default. When I use other cables, there are no problems. The thing is that this company makes (quite expensive) custom cables that I see recommended around in enthusiast communities and such, so I don't get why it seems like I'm the only one having problems with their design (it is unlikely to be a random defect when it happens with both of the cables I have from them).
 

AnalogSteph

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(it is unlikely to be a random defect when it happens with both of the cables I have from them)
Unlikely, yes, but not impossible. I have come across issues with 3.5 mm plugs and jacks disagreeing with each other, but it seems like you have narrowed down the problem to either connector soldering or the cable stock itself. (Try only moving specific sections at a time to isolate where the problem is coming from. If you have a multimeter, you may also be able to detect intermittency this way.) Were both purchased at the same time?

This sort of stuff happens. I once bought a pair of (admittedly inexpensive) microphone cables, which were very well finished but turned out to have microphonic cable stock - rustling noise galore once you applied phantom power. Let's just say it's not called a microphone cable because it makes sound by itself... I'm assuming it wasn't always like that and they got a bad batch of stock in and used it without testing, because who suspects that sort of thing.
 
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auxgroundloop

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Were both purchased at the same time?
They were not. They were purchased weeks apart.

Of course I can't be certain, but I do not think there is anything wrong with the amp's connector because other cables from different companies work just fine, combined with the fact that the problematic cable's company said

custom cable company said:
every once in a while you encounter a situation where the extra shielding is needed

So the cables were probably not from the same batch, and the company implies it's lacking some kind of shielding that is not standard to their regular design. I tried looking around for anyone else having issues with the company's cables and couldn't find anything at all. I just want to know what makes my case so special...
 
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