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HELP! FIXED Electrical noise interference

#21
Mistahbenn said:
Hi, I live in the City, and ive started picking up this noise on my preamps, Redhead, and my audio interface pres. WTH is that? Its erratic, but constant. Maybe we can have a laugh and pretend its aliens, but id like to eliminate it from my studio, because all that extra noise gets recorded! Any ideas?
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There are two different things happening in that recording.

The buzzy stuff at the start and the end is not broadcast radio interference. It is digital. Try removing all cellphones from the area, and also making sure you turn off wifi and bluetooth on any PC's (desktop or laptop) in the area, and also shut off all wifi routers and wireless access points and all other WiFi enabled devices. I will bet $5 that doing all of that will make it go away. If so, turn things back on ONE AT A TIME until you find the culprit. Then using clip-on ferrites at all inputs and outputs to the offending device as well as the receiving device will help. If you have enough wire, wrap the wire several times around the ferrite so that it passes through the hole in the middle as many times as possible before you clip it shut. (In other words, buy the BIG size ferrites, not the small size. In the attached photo, if you look closely, you can see that I managed to get two wraps of the LAN cable through the hole in the ferrite with the "Locus" label on it.
20200223_124136.jpg

The audio late in your recording is probably from a Ring doorbell or similar such security system that has audio capability, or baby monitor or something like that. You will have to spend a lot of time listening to the audio to get clues where the device is located. Then, if you find the offending device, you will have to be very diplomatic in handling it with the owner. They will not feel that they are doing anything wrong. Either their device doesn't comply with FCC Class B regulations, or else your device doesn't comply with FCC Class B regulations. If you try everything you can on your end and can't filter it out, you'll have to get them to fix it on their end, which will be very difficult at best. You may have to file a formal complaint with both the FCC and the manufacturer of their offending device, if the issue is on their side. Or if it's on your side, talking to the manufacturer of whichever device on your end is receiving the interference.
Step 1 for you to reduce or eliminate that is to use the shortest possible cables everywhere in your entire setup, since your cables are acting as receiving antennas.
Also, if you have a nearby FM broadcast station, a "mixing" effect can happen, whereby a low or medium strength signal blends with and modulates a very high strength signal that is overloading your equipment. Based on the recording, I would not rule out this scenario.
 
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#25
I was lucky enough to have a circuit available to dedicate only to recording gear. It solved some issues but not all of them. If you're picking up the kind of induced interference that xnewyorka explained you won't solve it with a new circuit. I would step through all of his(?) suggestions first.

And if the noise is on the mains you're still SOL.

For me an isolation transformer may be the next step if I ever graduate beyond "home studio".
 
#26
I don't know why anyone ever suggests disconnecting the ground from a device with a three prong cord end. This is a bad idea. It also does not really do anything other than expose the user to needless risk. The ground prong is connected to all of the non-current carrying metal in the device. These are the bits that are not in the circuit anyway, so of course it will work without it. However, if the device fails and develops a short, instead of safely tripping the breaker, it will electrocute the user.

Edit: Also, half the circuits in a single phase panel are common at the panel, and all are common at the neutral throughout the building.
 
#27
Mistahbenn said:
I got some of these but we’re too small... think the right size would help me? I think it’s a more serious simpler issue just need to find the source..
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This set goes pretty big, (large enough to go on the AC cables) and these have solved many EFI issues for me.
 
#29
I agree that it might be digital interference. I record voice and when a device has wi-fi on, I get noise. Turn off all wifi and Bluetooth off, and move cellphones etc. away from the recording gear.
 
#30
This reminds me of a recent pedal purchase that gave me unacceptable noise. I tried every power source imaginable (adapter, daisy chain, battery, adapter w/o battery, etc) and it turned out to be 3 things: an instrument cable and two patch cables.

It was the combination that made diagnosing the problem very difficult.
 
#31
When I play, I move my cell phone from my right pocket to my left pocket. In my right pocket, the interference (the phone is really close to the bass's electronics) sounds a bit like that.
 
#32
Mistahbenn said:
Hi, I live in the City, and ive started picking up this noise on my preamps, Redhead, and my audio interface pres. WTH is that? Its erratic, but constant. Maybe we can have a laugh and pretend its aliens, but id like to eliminate it from my studio, because all that extra noise gets recorded! Any ideas?
Click to expand...


Any compact florescents or LED lighting on your circuits?
 
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#34
I'm not sure if looking for problems with the power supply is the issue. You ask if someone is using something known to cause interference on the power supply? Well, yes. You are. Computers are well know to cause harmonic problems on the neutral, as are electronics in general that use switching power supplies. If you're convinced it's a problem with your power, get an isolation transformer like it was previously suggested. Otherwise you need to look for radio and electromagnetic interference, so build some tin foil hats for your gear.
 
#35
clockworkcorpse said:
I'm not sure if looking for problems with the power supply is the issue. You ask if someone is using something known to cause interference on the power supply? Well, yes. You are. Computers are well know to cause harmonic problems on the neutral, as are electronics in general that use switching power supplies. If you're convinced it's a problem with your power, get an isolation transformer like it was previously suggested. Otherwise you need to look for radio and electromagnetic interference, so build some tin foil hats for your gear.
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I will never resort to that, its crazy talk lol.
 
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#36
Mistahbenn said:
I will never resort to that, its crazy talk lol.
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It would actually work, you know, the tin-foil hat. Wrapping your gear tightly and thoroughly in aluminum foil would act as a Faraday cage and cut off any wireless interference. Of course, you wouldn't be able to work the controls, and things would start overheating pretty darn quickly... :eek:
 
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