ground loop (I think?) problem

[jhbrandt]

OOOoh, I C.

Yes, it is definitely the new comp. - Probably a 'hashy' power supply. OR it could be 'iffy' grounding on the firewire card. - most likely the PS of the new computer.

Have it tested.

-John

[Jakeman1086]

You may be right jhbrandt. But, there are some details you should be aware of.

I originally thought the problem was the power supply. I bought a 650W Corsair power supply when I first built the computer. The noise showed up, so I sent the Corsair back in exchange for a 500W OCZ ModXStream Pro. This new power supply did not fix the problem. It is still there.

The noise is not present when my old computer is connected to the firebox. BUT, if my old computer is connected to the firebox AND I turn on my new computer, the noise comes back - even though the new computer is not connected to the firebox.

My friend thinks that the new computer's power supply is generating RF that is being picked up somewhere.

[Jakeman1086]

Well, I'm very happy to tell you, I solved most of the problem - at its source. Apparently, it is the motherboard that is the culprit. I went into the BIOS and disabled some features -- power-saving features that optimize power usage such as CPU Enhanced Halt (C1E), CPU EIST Function, and a couple others. The squeal was gone upon reboot.

However, there is still an unresolved noise issue which I think is again attributable to the motherboard (a Gigabyte GA-EX58-UD5). I have a high frequency hum. It shows up at boot time at the same moment the old squealing noise showed up. This hum is constant and unwavering.

I am thinking maybe I should flash my BIOS?

[N88]

I've recently had a situation 'fixed' by trying one of those 3 to 2 prong ground lifts [at a technician's request]. A power conditioner has been suggested as a cure. I'm willing to try, but skeptical.
Any suggestions?

[PaulP]

Originally Posted by N88

I've recently had a situation 'fixed' by trying one of those 3 to 2 prong ground lifts [at a technician's request]. A power conditioner has been suggested as a cure. I'm willing to try, but skeptical.
Any suggestions?

That third prong you lifted is there to keep you alive. Disabling it is not
recommended. I'd fire the technician.

Paul P

[N88]

Originally Posted by PaulP

That third prong you lifted is there to keep you alive. Disabling it is not
recommended. I'd fire the technician.

Paul P

Sorry...don't want to give the wrong impression. The technician and I both knew lifting the ground isn't a cure; we were checking a suspicion.
The outlets have been tested, and I'm using a GFCI.

The power conditioner is what I'm wondering about.

[soundfoundry]

Same noise problem here. Asus P6X58D-E MOBO. Swapped out every hardware component. Played with every Bios tweak. Seems like luck of the draw with these X58 MOBO's. I started a seperate thread. Still no answers. The obvious lifting of the ground is the only solution. Unsafe as it may be.

[pbr]

I'm having the same problem, noise via motu 828 monitors firewired to one of two DAW machines. The noise is cpu activity related (corresponds to usage, will sometimes cease if the cpu is idle, dragging windows produces modulation, etc). If the the laptop machine runs of the battery and isn't connected to the ac strip, there is no noise. Plug it in and the noise comes through. On the PC, the noise disappears if I lift the ground (which, of course, I won't do for daily usage).

Would one of these take care of the loop?
Amazon.com: Ebtech Hum X Voltage Hum Filter: Musical Instruments

My PSU can draw 10a and this thing is rated for 6a so I'd probably have to connect my two 1a Truths to it, correct?

[spice house]

From this description, I have this same intermittent problem on one of my PCs it is not a grounding issue at heart! though I would call the noise more like hf clicking than chirping ;- ) Its from the mobo.. its something PC related interfering with your sound card though your mb - for me its my network card. It is intermittent likely because of the complex power modes and cycles of a laptop. It must be running more for the noise to leak through if that makes sense.Changing mobos will almost certainly fix the issue since the interference must travel through it to get to the soundcard

[Aof]

Most modern CPU/Motherboard combos produce some small amount of electromagnetic interference.
When the mainboard’s clock generator pulses, the extreme values (spikes) of the pulses create EMI (Electro-Magnetic Interference).
A well shielded computer case can help some times. Also, some BIOS have a "Spread Spectrum" option, that can be used to alleviate the problem. The bigger the value of the option, the less EMI, however, due to the nature of the technique, your system will (probably) be less stable, and don't even consider using it if you are overclocking.
I use a MSI Big Bang X-Power motherboard with Military Class Components (you have to love their marketing department) that is designed for overclocking. Not sure if it's because of that and the motherboard itself is better insulated or something, but I used to have a Core2Duo in an Asus motherboard that gave me the same type of noises that you describe, when moving windows, disk activity, etc., however in this new motherboard I don't have any kind of noise at all.
Also, always try to use balanced cables for audio.

[stooby]

I'm having a virtually identical problem that Jakeman1086 was originally describing along with many other people that have chimed in with similar issues. I created my own thread on GS with my system specs, details and my troubleshooting progress so far:
Need Help Eliminating High Pitched Monitor Noise!

Basically I'm experiencing high pitch noise through my Yamaha HS 50M monitors only when my Edirol FA-66 interface is plugged directly into my MacPro desktop machine via 6-pin to 9-pin firewire cable. When the Edirol is powered on, connected to my active monitors, but not connected to my computer, there is no noise. Only when the firewire connection is made from the Edirol to my computer does the noise occur.

If the computer is off but the Edirol is still connected to my computer, the noise is significantly reduced but still barely audible. Fortunately it doesn't seem to blend with the audio input signal recorded by my interface as I have been unable to record it in my DAW – it's heard only through my monitors.

Based on responses in my original thread I'm going to invest in a 4-pin to 9-pin firewire cable and connect my Edirol interface to my computer that way. Apparently a 4 pin connection doesn't carry a power signal which is what some people believe may be transmitting the interference/noise from my computer to my interface and into my monitors. Please correct me if I'm wrong about this. I'm still waiting on the cable and will report back if it helps with this issue.

But even if it does, it seems like this solution wouldn't be treating the source of the problem, which based on Jakeman1086's final postings in this thread, could possibly be noise caused by my computer's mobo. I'm curious to know if he ever completely resolved all of his noise issues that he mentioned in his most recent post.

[Jakeman1086]

For those of you unfortunate enough to be dealing with the same problem as me, the culprit is the x58 motherboard. I stumbled upon a solution today (yes, a year later ). I can't guarantee it will work for you, but it completely eradicated the noise coming out my studio monitors (and also the noise being picked up by my electric guitar - almost definitely emf).

Here it is (EXCITING!!!):

Put your computers in another room. Drill a hole in the wall, buy some extension cables, and get the computers completely out of the room.

Of course, I was doing this to remove general computer noise from my recording environment, but it solved the issue.

[griffy]

I recently had a very similar problem - I've been building a machine for recording, so it has to be as quiet as possible, passive cooling where possible etc... I got to the point where I could hear noise coming from the chipset. It's the exact same noise you hear from onboard audio (directly related to disk access, CPU usage etc), except that it's audible without amplification.
Obviously, the chipset is creating electrical noise that is causing other components to vibrate - the chipset itself can't produce any sound. And it's not capacitor whine.
I ordered and returned two ASUS boards because they were so noisy (P67 and H67 chipsets), before ordering a Gigabyte board which responded well to disabling C1 and overvolting.

That's right, overvolting. It seems that overclocking is so darn fashionable that manufacturers are selling their boards underclocked and undervolted. They expect you to overclock.

Having spent sh*tloads of money on this machine (and voided the warranty on a PSU with a hot glue gun, trying to fix phantom coil-whine) only to have it continue to produce headache-inducing noise was intolerable. I'll not be buying ASUS for a while.

Its a portable rack-mount setup. I've not tested it with my focusright saphire pro 40 yet, but since it takes mains power I'm hoping it's pretty well shielded. If I hear that noise in my recordings I might have to steal the muck-spreader from the farmer across the road and plan a tour of the UK HQs of said motherboard brands. Some of us like to use our computers for something other than d*cking around, and we expect better.