Ethernet EMI Filter for Better Digital Audio

DJM electronics has made the first Ethernet noise filter that might be helpful for an audio signal.  It is called the GigaFOILv3 Ethernet Filter and it is currently priced at $1,000.  

It is commonly accepted that EMI causes Noise in power cables.  When that power is used for audio, noise adversely affects the quality of the sound we hear.  This is especially the case for people who live in densely populated areas or in apartment buildings.  Power conditioners and well-made power cables can easily correct this problem.

Audiophiles also know the value of properly insulated and well-made connecting cables that transmit an analog signal.  Few dispute that a good RCA cable or speaker cable can noticeably impact sound quality.  However, the debate begins in earnest when it comes to transmitting digital signals.  Many people believe that 1’s and 0’s cannot be impacted by poorly made transmission cables or seriously affected by EMI.

For those who have let their ears rather than their mind decide the issue, good HDMI cables, USB cables and Ethernet cables abound.  Various products are made to reduce noise from USB cables that transmit music from a computer to an amplifyer, but up to now, there has not been a product that filters HDMI or Ethernet cables from EMI.  The GigaFOILv3 Ethernet filter is the first product that can make this claim.

DJM Electronics boasts that their patented technology is the only EMI/RFI filter for Ethernet on the market that offers 100dB performance from 10kHz to 10GHz and higher.  According to the company’s web site, “FOIL Ethernet filters utilize a fiber optic isolation link (FOIL) to maintain 100dB shielding integrity.  The filter converts only Ethernet packets, so there is no passband and no transmission of unwanted signals.”

I tested the GigaFOILv3 on my HRA music files as soon as I received it., I used a CAT 6 Ethernet cable to connect from the computer source to the GigaFOILv.3 unit and another CAT 6 to connect from the GigaFOILv.3 unit to the router.   The result was music that sounded veiled and somewhat muted.

Audio cables need burn in time and the GigaFOILv3 is no different.  After about 12 hours of burn in time, the muting was gone, but there was still a bit of a veil around the sound.

I borrowed an Audioquest Vodka Ethernet cable from the Cable Company.  When I replaced the stock CAT 6 Ethernet cables with the AudioQuest Vodka, the veil was lifted and the detail was restored to the music.  I think the combination of burn in time and better Ethernet cables made the difference.

Some audio gear requires as much as 500 hours of burn in.  I played music through the FOIL for a few days to see what happens.  So far I have not noticed any difference between the sound at 12 hours and the sound at 50, so it would not seem that this devise needs extensive burn in.

I did a limited amount of A-B testing (with devise and without devise) from this location and my preliminary conclusion is that the noise floor was lower and the sound is somewhat cleaner.  However, I can’t say that the music is $1,000 “better” or that what I am hearing isn’t an alteration of the sound rather than an improvement of the quality of the sound.

DJM Electronics recommends that you place the GigaFOILv3 near the DAC end of the signal rather than near the source end.  Since the computer and the DAC in my system are separated by about 50 feet of Ethernet CAT 6 strung behind a wall that seemed to make sense.  After I repositioned the GigaFOILv3 next to the DAC there did not seem to be any noticeable improvement in the sound from this position.  My conclusion is that location does not matter.

The next thing I did was to deal with the exposed female Ethernet plug on the GigaFOILv3.  As you can see from the picture, it protrudes from the shielded devise and it is not shielded.  Since the Audioquest Vodka Ethernet cable is shielded, I thought it might be important to wrap shielding around the protruding plug.  If left unshielded while everything else in close proximity to it is shielded, the exposed Ethernet plug will attract stray EMI like an antenna and likely negate the effect of what the devise is supposed to do.

Again I called my friend at the Cable Company and asked if I could borrow some EMI shielding material.  I wrapped it around the exposed Ethernet plug and tried my tests again.  This was much better.  The combination of the 12 hour burn in time, the Audioquest Vodka Ethernet cables and the additional shielding around the exposed Ethernet plug did the trick.

After more A-B testing with and without the GigaFOILv3 as modified, I conclude that there is a noticeable improvement in the sound quality and it does not sound like coloration.  It sounds like greater clarity.  Is there $1,000 worth of clarity?  Compared to the price of my PS Audio Direct Stream DAC, I think so.

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