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Electrical Noise and Interference leaking thru my mics
Old 5th February 2009
  #1
Registered User
 
migsoto's Avatar
 
🎧 10 years
Electrical Noise and Interference leaking thru my mics

Hi, I currently own a pair of SD Peluso CEMC-6 and a 2247 SE, the problem is I can't use the SD ones, they pick this nasty noise, like current and low frequency bumming, I also get a high pitch frecuency noise like a tube TV renders. I cannot use the 2247 on OMNI either, it picks the same noise, I wonder what could it be, are the mics broken?, is this some electrical issue?

This is my chain, Mics > Mogami Neglex 2534 quad Balanced cables (Made by Redco), Proco 18 Channel Balanced Snake (weakest link) > Preamp (whether UA 6176 or my 500 series ones on a BAE 11 slot Rack) > Lynx Aurora 16 > DAW, all feeded by furman PL-PLUS DMC which is connected to a Furman AR-15 Voltage Regulator.

The lights on the studio are controled by a simple switch, no dimmers, I've tried turning everything off, the frige, the HAVAC and even the lights of my whole apartment with no help. I also tried pluging the mic directly to the Pre, same noise though a litle softer.

I'm attatching a sound clip of the noise, on one of my post bellow. Please check

Thanks for your replys.

Mig
Old 6th February 2009 | Show parent
  #2
Lives for gear
 
iomegaman's Avatar
 
🎧 15 years
If you have a volt meter check the leads of your mic cable pins with the phantom power on...and then with it off...it sounds to me like psu noise, or voltage hum...

The voltage swing on 48 volts can go as low as 46.5 but it should not be to far out...if you're getting the same thing with the other mic it could be the mic pre.

Take it out of the chain next.

Process of elimination, one piece at a time.

Start with a known good cable, directly into daw thru Lynx.

next use the preamp.

After that the snake...at some point it will become apparant whats making the noise unless its a cumulative issue.

Some things just don't work well together.

I have a mic that I clip a discharge cable (those static bracelet cables you can get at an electronics store) to and make the singer/muso ground the other end, its a pain but it completely eliminates the buzz of this one mic (SD-phantom powered)...

I just got tired of looking for perfection and found something that worked.
Old 7th February 2009 | Show parent
  #3
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migsoto's Avatar
 
🎧 10 years
Thank you for your reply, I'll try al your sugestions and post the outcome.

Mig
Old 7th February 2009 | Show parent
  #4
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PaRaNoId's Avatar
 
🎧 15 years
me too! I been getting a hum from my mics when they are plugged in (48v OR NOT) that has been elusive in cause, except for that it honly happens in the afternoon (4-7pm). I was told it is dirty power from the electric provider....hmmmm. -JON
Old 7th February 2009 | Show parent
  #5
Lives for gear
 
iomegaman's Avatar
 
🎧 15 years
And thats why a $6.00 grounding wrist strap was such a good investment, I tell some of my clients (when I need to use it) that its so I can get more "vibe" from them.
Old 9th February 2009 | Show parent
  #6
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migsoto's Avatar
 
🎧 10 years
Ok I only had to run one test, pluging the mics directly to the preamps without using the snake, noise gone.

I changed my setup:

Power: 20amp 120V Outlet >Furman IT 20 II balanced Power Coditioner > Furman AR 15 Voltage Regulator > Furman PL-PLUS DMC Power Conditioner (Maybe this one is not necessary)

Audio:
Mics > Mogami Cable > ProCo Stage Master snake (20 Channels) > Preamps > Dsub in to Aurora > S/PDIF Out to Digi 003 > Firewire to PC.

I'm pretty sure the problem is that chepo Snake or maybe the fact that I'm runing phantom power thru that long cable IDK. I was thinking of replacing the snake as a solution, with a pair of 8 channel AES/EBU DSUB25 to XLR Female plugs, I need at least 50ft from my DAW to the studio, but I've been doing some research on the forums and I'm not really sure about it, so would I really benefit from it? what would be the better cable or the best option to solve this issue?

Oh yeah, I know almost nothing about the technical stuff, I do know how to solder though I don't trust my skills.

Thank you for your inputs.

Mig
Old 9th February 2009 | Show parent
  #7
Registered User
 
migsoto's Avatar
 
🎧 10 years
From shure webpage:

[h2]Shure A15RF[/h2]
The Shure A15RF In-Line RF Attenuator provides all types of balanced audio sys-tems with greatly improved immunity to radio frequency interference (RFI). It is especially useful in applications where balanced audio devices near strong RFI sources, such as AM radio stations, are connected by long cable runs.
The A15RF will not degrade system sound quality or alter system frequency response. In cases where interference is present but not audible, the A15RF can improve perceived sound quality by removing low level interference components from the audio signal path. It passes phantom power and is transparent to differential audio signals ranging from DC to 2 GHz.
The A15RF is a passive device and will not damage other equipment. It does not present any additional load to the signal sources, and can be used with phantom-powered mic-level or line-level devices.
Old 10th February 2009 | Show parent
  #8
Registered User
 
migsoto's Avatar
 
🎧 10 years
ok now I've really captured the noise that's making me crazy along with a radio station and a high pitch frecuency wave. It happened when I put the mics on the stands I didn't do that before.

Hear for yourselves
Old 10th February 2009 | Show parent
  #9
Lives for gear
 
iomegaman's Avatar
 
🎧 15 years
Maybe an inexpensive solution would be to get a Rolls phantom power box (I dunno maybe $25.00) and instead of running your phantom thru the snake run it from the mic...
Old 10th February 2009 | Show parent
  #10
Registered User
 
migsoto's Avatar
 
🎧 10 years
I've got a behringer DI box with phantom laying around somewhere, my worries are it could affect the signal
Old 11th February 2009 | Show parent
  #11
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iomegaman's Avatar
 
🎧 15 years
Quote:
Originally Posted by masp84 ➑️
I've got a behringer DI box with phantom laying around somewhere, my worries are it could affect the signal
Probably not much generally DI's are simply transformers.
Old 15th February 2009 | Show parent
  #12
Gear Head
 
🎧 10 years
Okay this is the sound I get erratically on our 2247 LE. Phantom is off at the Yamaha mixer, but the PSU of course is used to power the mic.

mp3 file attached..(normalized to a higher lever for purpose of this example)

Copuld this be the cable from PSU to the MIC? I am gonna consider getting a better shielded cable...this one passes by the computer tower..a Lynksys wireless router, and a fax machine..all known RF sources..

Perhaps that SHURE RF attentuater would be the ticket.

PELUSU_SN30_NOISE.mp3
Old 15th February 2009 | Show parent
  #13
Registered User
 
migsoto's Avatar
 
🎧 10 years
lol you've got something nasty going on there too... altough my noise isn't at normalized levels just regular tracking ones.
Old 30th November 2009 | Show parent
  #14
Gear Addict
 
1 Review written
🎧 15 years
Has anyone tried out the Shure A15RF or Canford XLR Inline filters? Just wondering if these actually work. I'm picking up a radio station (no idea if its AM or FM) out here from my mic and can't think of any other ways to resolve it

All I have connected are:
Mic -> Belden quad -> PreAmp -> Converter -> DAW

When I disconnect the Mic, I don't hear any problems, but the radio signals are audible as soon as I connect the mic. Anyone have some suggestions on what to do? What part of the mic itself can be problematic?
Old 11th April 2010 | Show parent
  #15
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once a roadie's Avatar
 
🎧 10 years
have not tried one but could use one...will they work on FM at 98.9 MHz?
Old 20th April 2010 | Show parent
  #16
Gear Maniac
 
🎧 10 years
buddy sounds like some equipments bad leakage.

I troubleshoot mine and found that my problem was solved when my neighbours photocopier is switched off.

You might want to look into them
Old 20th April 2010 | Show parent
  #17
Lives for gear
 
Wavebourn's Avatar
 
🎧 15 years
Check if cables are soldered correctly to sockets.
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