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My monitors have horrible EMI.

Its a really high pitched tone, high enough that my dad of 60 years can't hear it - but for my young supple ears of a 20-something year old its infuriating.

its not too loud, when something - anything of any volume - is playing you cant hear it, but as soon as its silence its noticeable, drives me nuts!

It's only happened since I built a new computer, my old PC was fine!

Can I just add - from experience this is not the same as a ground loop, and it happens in the signal chain below

Computer - External USB Soundcard - Monitors

Some observations:
Some USB ports don't cause the sound, but my soundcard only works out of certain USB ports (weird that one, cant figure that out either)
If the soundcard is OFF, the buzz continues, although quieter, until you unplug the soundcard.

Things I've tried:

Moving around plugs
Ensuring all electronics are on the same outlet.
physically moving my soundcard away from the computer
hitting my head against a wall.


Has anyone else got any tips?

Am I just unlucky that this motherboard + CPU configuration just causes mental EMI and it just has to leak out somewhere?

Cheers

is it your cellphone or cordless phone?

nope, i havnt a cordless phone and cellphone is off!

thanks for the reply.

anyone got anything else that might help?

Try these "ground lift adapters" you can find them at a hardware store.

Worked for me when I had this problem. I'm assuming you're using a surge protector? If not you should be..

Get 2 of these adapters, plug your monitor cables into them and then plug them into the surge protector and you should be golden.

Capture pt wrote: My monitors have horrible EMI.
It’s a really high pitched tone, high enough that my dad of 60 years can't hear it -

We wind coils. Then place them in a vacuum. To let an enamel get sucked into the coil. That locks every wire in place. Sometimes a wire gets loose. Then can vibrate in response to its resonant frequency when electrical frequency is just right.

You describe that type of failure. Often overlooked because a unique and high frequency (maybe > 20 Khz) and video mode must exist to create a best wire oscillation. Try different video frequencies and modes. Otherwise, a vibrating coil many be elsewhere (ie inside the monitor's power supply).

westom wrote:

Capture pt wrote: My monitors have horrible EMI.
It’s a really high pitched tone, high enough that my dad of 60 years can't hear it -

We wind coils. Then place them in a vacuum. To let an enamel get sucked into the coil. That locks every wire in place. Sometimes a wire gets loose. Then can vibrate in response to its resonant frequency when electrical frequency is just right.

You describe that type of failure. Often overlooked because a unique and high frequency (maybe > 20 Khz) and video mode must exist to create a best wire oscillation. Try different video frequencies and modes. Otherwise, a vibrating coil many be elsewhere (ie inside the monitor's power supply).

interesting, by video freq do you my (screen) monitors refresh rate?

supaOGninja wrote:

Try these "ground lift adapters" you can find them at a hardware store.

Worked for me when I had this problem. I'm assuming you're using a surge protector? If not you should be..

Get 2 of these adapters, plug your monitor cables into them and then plug them into the surge protector and you should be golden.

those look cheap enough that it must be atleast worth a go. I have a surge protector, aye - but i'll see if I can find the english plug version of these

actually, will that be safe removing the ground on my monitors?

I've used them for quite a while with no problems. Thinking about getting them again because I just moved house and my monitors hum slightly more than they used to.

I'm no electrician though, so if something blows up don't blame me lol

Not likely though. I don't know exactly what the grounding is for but other forums suggest opening up the cable and removing that third prong... THAT might be dangerous, these adapters are much safer.

It's a temporary fix though from what I've been told. If you get them however, and the humming goes away, you'll know immediately it was a ground loop problem.
Not sure how else to solve a ground loop problem without an electrician, so this is your best bet.

Just my 2 cents. I know it works though.

Capture pt wrote:actually, will that be safe removing the ground on my monitors?

Run stop signs. After running 10 intersections without crashes, that proves ignoring stop signs is perfectly OK. Same claim is found in that cheater plug. Due to danger, it is banned in Canada. But that is a fact based in knowledge understood by engineers. He just knows the educated must be wrong?

Safety ground exists only to make more work or make your life harder? Nonsense. The electrical engineer says that cheater plug only increased threats to human life. And eliminates other hardware protections. The same engineer explains why high frequency sound may be created. And defines tests to maybe eliminate symptoms from an always defective hardware part. More useful recommendations are obvious for two reasons. It says why the noise can happen. And that answer includes numbers. A recommendation without numbers implies ignoring all stop signs is also perfectly acceptable.

Capture pt wrote: interesting, by video freq do you my (screen) monitors refresh rate?

The TV transmitter station (called your computer) transmits many different video modes at many frequencies. Frequency for screen refresh. Frequency for numbers of lines. Frequency for pixels in the line. Changing refresh frequency and video modes (on the video controller setup page) changes all those frequencies.

Changes made in the TV transmitter then result in various frequencies inside the TV receiver (your monitor). A computer simply commands what frequencies will exist inside a monitor.

What we do not know. Is the defective part related to those frequencies? Or is it inside the monitor power supply that will also generate 20,000 hertz or higher to create 0 hertz DC voltages.

yah, im with you. I think those ground lifters are banned here, as I cannot find anywhere that sells them.

Ill play with my video settings, see if it helps.

Cheers!

If this is actual interference from another source, there isn't much you can do about it.

If it's being generated by the amplifier or psu in your monitors, there isn't much you can do about it.

I highly doubt it has anything to do with structural wiring in the house if it's high pitched.

This is exactly why I will never buy monitors with built in amplifiers.

well its only started since i changed my computer

so changes are:

CPU + Cooler
Motherboard
RAM
PSU
Case


I reused hard drives and my GPU.

My old man just reckons that the new breed of multicored processors just churn so much data that interference just has to leak out somewhere.

When it drives me to the next level of insanity I might try a different computer PSU.

maybe i said this before, but try wrapping your monitors in tin foil, as well as the audio and power cables. it's worth a go.

Capture pt wrote: My old man just reckons that the new breed of multicored processors just churn so much data that interference just has to leak out somewhere.

Your 20,000 Hz audio sound has no relationship to a tiny power, 2,000,000,000 Hz, radio wave. He is confusing an audio signal with a radio signal well above the highest frequency in any TV. If a CPU is causing interference, then you have already been driven mad by larger signals from microwave ovens and televisions - especially from older non-HD TVs.

Ignore wild speculation especially when numbers are not provided.

I have a usb soundcard as well, and I've noticed that I have a similar problem with noise. Maybe usb soundcards have these kinds of problems? Suppose it's something worth looking into if you haven't solved your problem yet, OP.

I havnt found a fix yet. Tried ferrite filters other day - no luck.

just confusing as to why the last computer was fine but this one causes issues.

with my old PC I had the old mouse wheel hum and stuff when I had my monitors coming out of the built in soundcard, then I bought an external - which fixed that.

perplexing. i tried all video settings etc. really annoying. Sighhhh.

Capture pt wrote: Tried ferrite filters other day - no luck.

A number for the relevant frequency range was provided. 20,000 Hz. Ferrite filters are typically for blocking frequencies at and above 100,000 Hz. A 20,000 hz noise would pass through unimpeded.