Hearing ground loop hum, not sure what to do

[Vaxin8]

So I'm currently using a FiiO K11 for my Sundara but sometimes I heard audio crackle that starts out small then gets a lot worse seconds later. Not knowing what was going on, I sent my unit to FiiO and they found no problem. They even sent it back with a power plug matching my country since I was using a JP plug(K11 was originally bought in Japan). Now that I have my K11 back, it was a fine for a few days until I heard that audio crackle again. At this point I didn't know what to do and thought my K11 was defective. Then I started researching about it until I stumbled onto ground loop hums and they sound really close to what I experienced. My cousin chalked it up to dirty electricity because where I live(Philippines), we need voltage regulators for stuff like refrigerators and computers. Anyways, below is how my current setup looks:

PC Specs:
Ryzen 7 5700X3D + MSI B550M Pro-VDH Wifi + Gigabyte RTX 4070 Super + 32GB DDR4-3200 + Gigabyte UD-750GM 750W Gold PSU
Audio Specs:
DAC/AMP: FiiO K11
Headphones: Hifiman Sundara with 4.4mm cables

The PC is connected to a power strip at the moment because my voltage regulator can only handle 500 watts.

 

[staticV3]

Hi @Vaxin8! Welcome to ASR.

The first thing that I would try is to connect the K11 to your PC via Optical, instead of USB.

Many PC motherboards have an Optical output built-in.
If yours doesn't, then you can use a Hifime UT23 or Cubilux SPDIF Converter.

 

[Speedskater]

"Ground Loop" noise is power line related low frequency hum and buzz.
What you describe is the arcing and sparking noises that cause HAM radio operators problems.

 

[AnalogSteph]

For a start, I would try plugging the K11's power supply into the voltage regulator.

If your power is that dodgy, I would try upgrading the voltage regulator to a proper online UPS. The kind that is rack-mounted, super heavy (that's lead acid batteries for ya) and rated 1000 VA up, from the likes of APC or Eaton. They are commonly found on the used market for cheap since replacement battery packs cost almost as much as a new one. It takes a bit of elbow grease, but especially older battery packs can be refurbished with quality new batteries reasonably easily. Very old models with a very high battery float voltage may be better avoided, but one 10-15 years old should be OK.

 

[Vaxin8]

Hi @Vaxin8! Welcome to ASR.

The first thing that I would try is to connect the K11 to your PC via Optical, instead of USB.

Many PC motherboards have an Optical output built-in.
If yours doesn't, then you can use a Hifime UT23 or Cubilux SPDIF Converter.

Yeah unfortunately my motherboard doesn't have an optical port.

Thanks for the recommendation though, while these aren't available here locally in my country I'll see if there are alternatives like them here.

 

[Vaxin8]

For a start, I would try plugging the K11's power supply into the voltage regulator.

If your power is that dodgy, I would try upgrading the voltage regulator to a proper online UPS. The kind that is rack-mounted, super heavy (that's lead acid batteries for ya) and rated 1000 VA up, from the likes of APC or Eaton. They are commonly found on the used market for cheap since replacement battery packs cost almost as much as a new one. It takes a bit of elbow grease, but especially older battery packs can be refurbished with quality new batteries reasonably easily. Very old models with a very high battery float voltage may be better avoided, but one 10-15 years old should be OK.

I have tried plugging the K11 into the voltage regulator but it doesn't work.

That said, I was planning on buying a new voltage regulator to plug my pc into in the coming months but I'll consider getting a UPS but they are also much more expensive. As for the used market in my country, stuff could be dodgy but I'll check it out. Thanks for the advice, though.

 

[theREALdotnet]

I'd eliminate the voltage regulator first. It looks like all of your devices have switch-mode power supplies that work with a wide range of mains voltages. Check your FIIO power adapter to be sure. I would also eliminate the ground-removing travel adapters and plug everything into three-prong mains using the supplied power cables.

 

[Vaxin8]

I'd eliminate the voltage regulator first. It looks like all of your devices have switch-mode power supplies that work with a wide range of mains voltages. Check your FIIO power adapter to be sure. I would also eliminate the ground-removing travel adapters and plug everything into three-prong mains using the supplied power cables.

It's a good idea but unfortunately the outlets in my room are only 2-prong. Like this one below: