# What exactly do ferrite cores do?



## Illah

???

 --Illah


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## Jeff Wong

They're a ceramic-like magnetic material that is mostly used to to absorb EMI (although they have other uses.) I've found they strip away musical information when used on analogue interconnects and don't recommend them for that application. They're probably best used on power cords to reduce noise.


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## Sinbios

The magnetic field blocks out high frequency RF noise.


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## Illah

Cool, so I have an extra one lying around - I might snap it on the cord from my Elpac to my Gilmore Lite.

 Thanks!

 --Illah


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## michaelhwolff

"The magnetic field blocks out high frequency RF noise"

 I'm curious as to how the magnet differentiates the high frequency "noise" and the clean high frequency signal coming down the cable.


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## Sovkiller

Quote:


  Originally Posted by *michaelhwolff* 
_"The magnetic field blocks out high frequency RF noise"

 I'm curious as to how the magnet differentiates the high frequency "noise" and the clean high frequency signal coming down the cable._

 

They have an elf inside the cable that tells the ferrite core what to do...... 
	

	
	
		
		

		
			











 The ferrite blocks the RF and EMI (mostly above listening HF spectrum) that is outside of the cable to go the inside of the cable...


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## Anders

The ferrite ring increases the cable impedance at high frequencies but should preferably not affect the impedance in the audible range, or at the AC frequency. Obviously it is easier to achieve this at 60 Hz than over a great bandwidth.


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## Illah

So would you say my extra ferrite should go on the interconnect or the elpac power cord? The power is already in a monster power conditioner so I imagine that's clean, but the interconnect is from a computer with all the noise of that environment (though it is a fully shielded cable I built myself).

 As for the ferrite blocking audio signal, there are a bunch of cords on the market with ferrites on them...

 For now its on my power cable.

 Thanks,

 --Illah


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## Anders

Ferrite rings work best on powercords but the effect is usually marginal and not always audible. They dampen the noise a little rather tham remove it. They can have a negative effect on audio cables and reduce high frequency extension, but that depends on factors as how strong the ferrite ring is.
 You can try it only different positions and hear if something changes.
 One possiblity could be to use it for pre-cleaning before the Monster.


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## ZGLISZCZ

Hi Guys, I have some lame question If I will install  few of them one after another on power cord will it clean noises more? while ago I get Roksan Kandy mk3 and its noisy as hell, I can hear it especially when I plug my headphones. I can hear mouse movements and hdd working plus something that might be my fridge... its so annoying. Im sure noises dont come from my imput because I can hear them even if I unplug all inputs. I have Tacima 6-Way Mains Conditioner with Surge Protection but it doesnt seems to work... Im not sure if I actually have ground... I rent this flat. so the question is will those ferrite rings help me, and will they increase filtering if I will install few of them on power cord? if yes I will buy hundred of them and go mad installing them everywhere... damn noises! Argghh


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## Speedskater

Ferrites filter radio frequency interference (RFI). Different model #'s filter different frequencies. Different positioning will have different effectiveness.
 Mouse movement noise is probably not an RFI interference problem.
 Refrigerator (and similar) noises should be dealt with at the source.
  
 **************************************************************************
 Jim Brown, past AES committee chair on EMI/RFI interference, has several papers on using ferrites. Don't let the word 'Ham' fool you, much of the paper also applies to audio systems.
  
*New Understandings of the Use of Ferrites in the Prevention and Suppression of RF Interference to Audio Systems*
 http://www.audiosystemsgroup.com/AESPaperFerritesASGWeb.pdf
  
*Understanding How Ferrites Can Prevent and Eliminate RF Interference to Audio Systems*
 http://www.audiosystemsgroup.com/SAC0305Ferrites.pdf
  
*RFI, Ferrites, and Common Mode Chokes For Hams*
 http://www.audiosystemsgroup.com/RFI-Ham.pdf


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## ZGLISZCZ

Hi Speedskater,
  thanks for your help. If that would be my flat probably I would install all wires in the walls again, but I renting it. I will take look at those articles. I really thank you for reply.


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## AegisAvantGarde

Hey Ilah im also thinking of putting ferrites in all my AC chords. By the way, I wanted to buy some Grado Rse2 recently, I wanted a grado fan's point of view as to what is the characteristic sound of Grado? I want to join the Grado Wagon!


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