Nothing easy without cost: network powerline adapters EMI

tdxloki

Estimable
Oct 30, 2014
4
0
4,510
I am seeking advice, thanks.
I am using some powerline adapters to get "better" speed to my basement and kitchen. They do provide faster than wifi speed, at a cost, a ton of electrical noise, I'm not sure which, EMI or RFI. It is most noticeable when using headphones.

Here is the setup:
NAS->FiOS Router->ZyXEL Powerline PLA5205 Adapter->Computer (Gigabyte Gaming 5 motherboard with DACUP USB)->Audioquest Dragonfly->Audioquest Golden Gate Cable, 3 meter->NAD HP50 headphones

I can hear the noise, pops, crackles and clicking, in the headphones when no music is playing or during a quiet section of a track. When I unplug the network cable the noise completely goes away. Playing from a local drive is the same, noise when the network cable is plugged into the jack, quiet when unplugged. Furthermore, if I transfer a file to my NAS from the local drive or to my local drive from the NAS the line noise "intensifies." It is a bit louder and more of a consistent buzz. The motherboard has the so-called DACUP USB ports which supposedly supply "cleaner" power to the USB ports over conventional USB ports.

What have I tried? Not much, but here is some data.

NOISE:
1. I tried a ferrite clamp on the network cable - no effect.
2. I tried different outlets for the powerline adapter (probably same circuit) - no effect.
3. I tried USB3 ports (non DACUP ports) - no effect.
4. 1/8" female/male 6 foot extension cable - no effect.
5. I plugged the powerline adapter into my surge protector. (It worked but at 1/2 the speed when plugged in the wall outlet.) - no effect

NO NOISE (but not a workable setup):
6. I temporarily moved my FiOS router to the basement to bypass the powerline adapter. (The NAS was disconnected so I could not test file transfer noise.) The line is silent, all conditions.
7. Stock headphone cable (too short to use without extension) and "lower quality" 1/8" inch cable. The line is silent, all conditions.
8. Cheap external powered computer speakers - no EMI/RFI. The line is silent, all conditions.


What can I do to eliminate the noise but not filter out the throughput of the powerline adapter?
A power conditioner? (Hopefully inexpensive, i.e., <$100)
A network switch between the powerline and my computer? (Hopefully inexpensive too)
String RJ45 along the floor about 60 feet? Yuk. I cannot string cable though walls, so if I have to use a direct line, it will be very long and tacked down along the floorboard, doorways, and stairs - not cool.

Thanks for your help!!
 

tdxloki

Estimable
Oct 30, 2014
4
0
4,510


The headphones are connected to a USB DAC, the Audioquest Dragonfly. There is a standard 1/8 output on the Dragonfly DAC which I connect to the headphones with stock or Audioquest 1/8 to 1/8 analog cables.



Corsair RM Series RM750 — 750 Watt 80 PLUS Gold Certified Fully Modular PSU


Nice idea! A new experiment! I have not tried this yet. I'll give it a shot. My guess, there will still be noise...

 

tdxloki

Estimable
Oct 30, 2014
4
0
4,510
UPDATE:

I may have a ground loop issue! I used a cheater plug on the 3-prong powerline adapter and it eliminated all the noise, even during file transfers when the noise was the worst.

So, now what? Do I need an electrician? Is it unsafe to leave the cheater plug attached?

At least I found the source of the noise. Now how can I fix it?