Electrical interference when recording

Fishybob

New member
Hi. I've had a problem recording since getting my new dual core athlon pc. I originally posted this in the PC forum because I thought it was soundcard related but I have realised that it's an electrical issue.

When I record a track I can hear an electrical interference. I have all my stuff set up with a patch bay and checked everything. It's now become obvious that the noise comes from the pre amps when they are plugged in (power). If I listen to the track coming from a pre that is plugged into the mains (whether it's on or not) the interference sound is present but as soon as I unplug the pres power cable the noise goes away. This is exactly the same with both the penta and twintrack.

I haven't changed anything around except the PC and I can't just unplug that to test it! The extention leads are set up as 2 coming from the same port on the wall leading to 2 4ways.

Am I right in thinking this is an earthing thing?

Any help very welcome, I'm desperate to record some new tunes.


***Cubase sx3, AMD 4600 Dualcore, 2Gb fast RAM, ATI RADION graphics card 256mb, NTK, NT1000, SE2a, Penta, Twintrack, etc...***
 
Yup. No luck there. It's odd how it's just on the input signal, playback is fine.

I haven't added any new devices other than the pc itself.

What's also odd is that you can 'hear' when something happens on the screen... mouse movements, minimising pages. If you monitor teh signal coming in while doing other stuff the noise changes accordingly...
 
I had an issue similar to this with my monitor. Did you get a new monitor with the new computer?

Try turning the monitor off and see if the sound goes away.
 
Hey-

This looks like a good place to get started.

Internal soundcard, or USB/Firewire connector?

Either way, you're probably dealing w/ 60 cycle hum.

RF interference sounds like an old AM radio between stations.
If it's a steady noise, doesn't modulate, you probably need a
power conditioner.
Household current's not great directly out of the wall for audio.

For in the $100-130 range, I recommend a Monster Power strip
(BestBuy, Radio Shack...).

They make a huge difference.

Kirk/FKA1
 
Internal M-Audio 24/96 x2 soundcards. No new monitor. Never had problem with power before... Stumped!

If it's a cycle hum problem what can be done... other than the power conditioner?...

Also what's the hum rate for the UK? Is it 50 rather than 60??

Please keep helping
 
Yes, you are in the UK, it's 50hz, not 60.

First, try switching the suspect pieces to different inputs, see if that solves the problem. Also try different gear in the inputs where you are getting noise.

Try running the suspect pieces straight into to computer, skipping the patchbay.

The goal is to narrow down where the problem is.
 
FKA1 said:
If it's a steady noise, doesn't modulate, you probably need a
power conditioner.
Household current's not great directly out of the wall for audio.

Kirk/FKA1

In my experience ground hum issues need to be solved where they happen. A power strip, no matter how fancy, can't help.
 
Could this be an IRQ issue???


The interference does change when I move my mouse of open/close windows... kinda like a static zipper...
 
i noticed you are using an internal soundcard here. i am not too familiar with M-Audio products, but I am sure they offer shielding. I can replicate exactly what you describe with my ThinkPad's internal sound card. It I put on a pair of headphones right off the card, I can hear all the noises asscioated with the computer (click mouse, pressing keys) - there are serious of High FQ noises that go along with it. Is that a shielded card? It must be, so perhaps there is something wrong with the slots you are using on you machine?
 
i had a noise on my system and it turned out to be the graphics card try unpluging the monitor when you record something and see if the noise is still there. i had a winfast 6200 with a passive heat sink on it ,i dont know if it was a sheilding problem but my ati radion 7800xl cured it.

hope this helps
 
Fishybob said:
Yup. No luck there. It's odd how it's just on the input signal, playback is fine.

I haven't added any new devices other than the pc itself.

What's also odd is that you can 'hear' when something happens on the screen... mouse movements, minimising pages. If you monitor teh signal coming in while doing other stuff the noise changes accordingly...

I've experienced the same thing but I never figured out the source of the problem. I did notice that an optical mouse seemed to make the problem worse. I still to this day get an occasional buzz in my output signal which is some how related to my crt monitor (I can hear my monitor doing something). I think it's some kind of grounding issue but who knows.
 
OK. If I go directly into the soundcard from my guitar the signal is fine. I guess this rules out IRQ at least!

The 4 ways I'm using are pretty old so I could try replacing those if you think it'll help?

This noise happens with both my Penta and Trakmaster so they can't have developed the same problem at the same time... Must be power, mustn't it???
 
They are ALL plugged into 2 4ways that are both coming out of the same dual socket.

I even tried it with the PC in a different one... no change!
 
i would advise the process of illimination. Pull out everything including usb devices. Update your driver for the interface or reinstall it. I would try another mic pre and other cables.
 
Fishybob said:
OK. If I go directly into the soundcard from my guitar the signal is fine. I guess this rules out IRQ at least!

The 4 ways I'm using are pretty old so I could try replacing those if you think it'll help?

This noise happens with both my Penta and Trakmaster so they can't have developed the same problem at the same time... Must be power, mustn't it???

Didi you try the basic troubleshooting steps? Your stuff all goes into a patch bay, right? Suspect #1 right there. A device full of shit connections. Reseat all your cables. Reseat your soundcard connections.
 
It sure sounds like a monitor problem, but I guess you have checked into that.

Do you have your PC and recording gear plugged into different circuits, or chained along a string of power strips? I've heard of such situations leading to hums - I can't recall the terms, but it's caused by subtle differences in the ground.
 
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