Author Topic: Fixed my first ground loop  (Read 766 times)

Offline Zilch

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Fixed my first ground loop
« on: December 02, 2021, 01:00:07 PM »
Sometime back in July I got a new Dell laptop plus a matching Dell monitor of pretty decent specification.  Needless to say I was very excited!  First up, I remove and throw away the 500GB 7200RPM drive (hehe, not really) and replaced it with a WD Black SSD.  This SSD was gifted with a fresh new license of Windows 10 Professional.  With Windows configured and my usual software installed, all is going very well now, until later that afternoon I connect my craptastic JVC headphones to the 3.5mm socket.  It sounds fine; what you'd expect from a laptop DAC.  Fast forward approix. 10 min, and a funny crackle sound has started to develop.  Naturally this annoyed me :nono:.  Quickly, I connected it to my phone and listened... but the crackle was not there.  This meant the laptop was the source of my trouble.

Jumping ahead by a few months 'till today, and I somehow got an idea that it could be a ground loop.  Normally this would not be the case, as the ground from the laptop charger must not be connected to earth.  With that said, I took my multimeter and checked between the earth on the monitor's IEC socket and the ground on the 3.5mm headphone socket on the laptop for continuity (with both connected via an HDMI cable and a USB cable for the built in hub).  Success, I think, as I see zero resistance between the two points. :facepalm:

Thankfully the fix was as easy as drinking water.  I got an extra cable which has an attached 3 pin plug with a female IEC connector.  I cut off the mold injected IEC plug and replace it with the last mechanical one I had lying around.  Success, again!  Now the crackle is completely gone.

I was rather surprised that it not only worked, but that I also didn't blow up something... as is all too common here :sh1tstirrer:

This thread here helped me understand some of the details of how grounding works.
If you don't understand the difference between "their", " there" and "they're" then your a idiot.

Offline Zilch

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Re: Fixed my first ground loop
« Reply #1 on: December 02, 2021, 01:45:59 PM »
Mods can delete / lock / whatever this post.  Seems I got a tad too excited as the issue is now back :facepalm:

Now I remember why I got that Theta :shh:
If you don't understand the difference between "their", " there" and "they're" then your a idiot.

Offline Family_Dog

Re: Fixed my first ground loop
« Reply #2 on: December 02, 2021, 02:45:40 PM »
No, we look forward to the next gripping episode!

I have no real suggestions though, perhaps update your laptop audio drivers?

Are you using an external monitor with the laptop? Try using only the laptop display.


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-Eric

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Offline DACMan1

Re: Fixed my first ground loop
« Reply #3 on: December 02, 2021, 03:03:31 PM »
Crackle is usually not a ground loop. The source is most likely the laptop charger itself. Try running off battery and see if the problem persists. If it does, you can probably solve the issue by getting an Apple USB-C to 3.5mm or better DAC.

Offline chrisc

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Re: Fixed my first ground loop
« Reply #4 on: December 02, 2021, 04:56:30 PM »
Or a damaged socket on the computer
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Offline Zilch

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Re: Fixed my first ground loop
« Reply #5 on: December 02, 2021, 06:00:43 PM »
Eric I'll have to try some more.  I did use it for a short time during load shedding and didn't notice anything.  That said I'd quite forgetful.

Thanks DACMan.  Will do some testing.  I did recently buy a Theta DS Pro Prime 1 from the forums, so I just need to get some USB to SPDIF converter for that to work.

Chris a damaged socket is nearly impossible.  It's a Dell Latitude 5290, so from their business lineup; much better built than their regular consumer counterparts.

Thank you gents for the input!
If you don't understand the difference between "their", " there" and "they're" then your a idiot.

Offline Family_Dog

Re: Fixed my first ground loop
« Reply #6 on: December 02, 2021, 07:49:39 PM »
I'm inclined to agree with DACMan1 here, I figured the standard Dell PSU should be fine but it certainly is worth a try. Is it the 90w (or more) PSU?

An external monitor is unlikely to cause the problem, reading your opening sentence I thought you were using it and it would be easy enough to disconnect it completely - video as well as PSU - to ascertain whether it had any affect or not.


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Offline Nikkel

Re: Fixed my first ground loop
« Reply #7 on: December 02, 2021, 08:17:41 PM »
Does the crackle happen with all the sounds? Or on specific software?

You're a bit vague there...

It could also be a live playback latency issue in AV software... maybe even an up sampling issue IF maybe you do up sample... bumping up bitrates on output device in Win sound settings can also mess you about...

Just trying narrow down suspects :2c:

Offline marantz123

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Re: Fixed my first ground loop
« Reply #8 on: December 02, 2021, 08:40:20 PM »
Sounds like a contact problem between the jack socket contacts and the male plug. Could be a bit of corrosion or something crawled up in there and died leaving some lovely acids behind. Seeing that you are on the coast, a bit of corrosion is a possibility. Try cleaning the socket somehow..note...caution....spraying a cleaner in there may damage something. Whatever you do, disconnect battery and AC power first. No idea what the socket looks like, wouldnt expect there to be a dry/cracked solder joint on the socket pin/s.. but anything is possible.  :nfi: Pop on over to Carbonite, PC /laptop gurus abound there.
« Last Edit: December 02, 2021, 08:46:07 PM by marantz123 »

Online naboo

Re: Fixed my first ground loop
« Reply #9 on: December 03, 2021, 04:41:49 AM »
Fray the end of a toothpick, stick it in, twirl around, retract.

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Offline ALF

Re: Fixed my first ground loop
« Reply #10 on: December 03, 2021, 09:52:50 AM »
If you get a real ground loop when using laptop then you need to disconnect the ground connection on the wall plug, I suspect that is why most Apple laptops supplies does not use ground only a two point connection.
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Offline DACMan1

Re: Fixed my first ground loop
« Reply #11 on: December 03, 2021, 10:05:51 AM »
If you get a real ground loop when using laptop then you need to disconnect the ground connection on the wall plug, I suspect that is why most Apple laptops supplies does not use ground only a two point connection.
Depending on the PSU design, that is not always a good idea - some of them will have leakage to ground to compensate for capacitive coupling through the transformer, so removing ground will mean you have capacitive coupling.(when the other ground path is absent)

Offline Zilch

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Re: Fixed my first ground loop
« Reply #12 on: December 03, 2021, 07:51:37 PM »
Thanks for all the input guys!

I have listened again, and can confirm that the laptop is making the funny crackle even when it's not connected to power (nevermind the monitor).

Either it's a driver issue or the laptop is a defective unit.

I recall testing Debian on this laptop (before switching back to Windows) and I recall it handling the drivers much better.  But I really don't feel like transferring all my files, especially to the unstable mess that is Linux (yes, it's great, but I have had bad luck with it).
If you don't understand the difference between "their", " there" and "they're" then your a idiot.

Offline Family_Dog

Re: Fixed my first ground loop
« Reply #13 on: December 03, 2021, 08:13:52 PM »
Download and run the Dell Diagnostics Tool, it might find something that requires attention or updating.


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-Eric

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Offline Zilch

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Re: Fixed my first ground loop
« Reply #14 on: December 03, 2021, 08:29:36 PM »
Thanks, Eric.  Will try tomorrow :2thumbs:
If you don't understand the difference between "their", " there" and "they're" then your a idiot.