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Reviewing the DJM Electronics GigaFOILv4 Inline Filter

The engineers at DJM Electronics did it again! The GigaFOILv4 inline filter for Ethernet noise dramatically improves upon the original GigaFOIL and delivers a lower noise floor for digital music transmitted through an ethernet cable that anyone, even the staunchest of anti-tweakers and the hearing impaired can hear.

Even with the best Ethernet cables, noise is as much of a problem when a digital audio signal goes from a source component to a DAC as it is for power cables connecting the wall outlet to a component. Regardless of how shielded that cable may be, electromagnetic interference creeps in to the signal and adversely affects sound quality. The longer the length of the Ethernet cable the more distortion!

The First Ethernet in-line Noise Solution

Until the engineers at DJM Electronics delivered the first GigaFOIL to the audiophile market several years ago, there was no product that made any meaningful reduction in the noise picked up by an Ethernet cable other than to buy a good, high-end Ethernet cable like an AudioQuest Cinnamon or better or a Wireworld cable. Nordost didn’t even make Ethernet cables until several years ago and many high-end cable companies still ignore the Ethernet cable in their product line.

Indeed, naysayers insist that there is little audible difference between stock cables that carry a digital audio signal and expensive, high-end cables that carry a digital audio signal. Ones and zeroes are just ones and zeroes and the cable they travel on does not change them. While this thinking is certainly logical, like much with high-end audio, the proof is in the hearing and sometimes the “science” or logic cannot be squared with what is heard.

For the disbelievers, try the GigaFOILv4 inline Filter

The GigaFOILv4 inline filter is the best (and only) Ethernet noise filter on the market. It is a noticeable improvement to DJM Electronics’ original GigaFOIL filter whether you place it near the source or at the end by the DAC or component receiving the source signal.

DJM Electronics recommends placing the GigaFOILv4 at the end of the line just before the signal reaches the player component (i.e. The DAC). Placement at the end of the line scrubs any noise that might creep into the signal along its journey from the digital source component, especially if the Ethernet cable goes through walls.

Here’s how it works, as explained by DJM Electronics:

The GigaFOILv4 – INLINE is the newest generation of the FOIL™ brand of Ethernet filters. Based on patented Fiber Optic Isolation Link (“FOIL”) technology, the GigaFOILv4 – INLINE utilizes fiber optics and specially designed circuitry to prevent 99.99999999% of electromagnetic interference (i.e. “Noise”) from passing through the filter. 

The filter covers a frequency range of below 14kHz to beyond 18GHz and does not require a passband, meaning the only signal passing through the filter is the clean digital Ethernet signal.

What Improvement to Sound Quality Could I Expect from GigaFOILv4?

For test purposes, I installed the GigaFOILv4 in a simple audio system installed in a 1950’s New York City apartment building. Those old big buildings have horrendous power and tons of EMI from outside lines and from years of wiring and rewiring in all the units in the building.  The New York City system is simple.  There are five Totem Acoustics on wall speakers powered by an Integra 7 channel receiver.  I use the DAC from the OPPO 105 as my DAC for music.  These components are installed in the rack under the TV.

The “guts” of the system are in the closet.  There you will find the router, internet, cable TV box, and a Drobo 5N where the digital music library is stored. The power is fed from the dedicated wall outlet through a Valhalla 1 power cord through a Nordost QRT to a Nordost QBase Distributor and then through Valhalla 1 power cords to the back-end components in the closet.

J. River Media software controls the music delivery which runs from the Drobo 5N in the closet to a Mac Mini in the rack. The digital music travels through an AudioQuest Vodka Ethernet cable to the wall. At the rack, another AudioQuest Vodka Ethernet cable takes the signal from the wall to the Mack Mini. An optical cable takes the signal from the Mac Mini to the OPPO 105 located right next to the Mac Mini. Audience 24SE RCA interconnects take the sound from the OPPO 105 to the Integra Receiver. The components in the rack are all powered by a PS Audio P-5 power re-conditioner connected from a dedicated wall outlet by a Shunyata King Cobra five-gauge power chord.

Proper Placement of the GigaFOILv4

Ideally, following the DJM Electronics recommendation, the GigaFOILv4 should be placed in the rack between the Ethernet wall outlet and the Mac Mini. However, since it is easier to work in the closet then to pull out the tightly packed rack, I installed the GigaFOILv4 between the Drobo 5N and the Ethernet wall outlet in the closet.

Not expecting any great improvement in sound quality from this installation, I selected Amber Rubarth’s, Good Mystery, from Sessions from the 17th Ward which I use as my reference audio and took a diet Coke out of the refrigerator. I never opened the can of diet Coke. It was shock and awe. The quality of the sound that came out of the Totem speakers was night and day better with the GigaFOILv4. You wouldn’t need a specially trained ear or use any electronic measuring devices or even need to prepare yourself with a proper seat in the sweet spot to listen for a subtle improvement. The improvement was not subtle at all. The improvement was palpable and clearly discernable by anyone, even the non-audiophile or most skeptical audiophile.

Since I always hate the descriptions that audiophile writers use when they review cables, power cords and tweaks, I am not going to describe the improvement other than to make the claim that the GigaFOILv4 significantly lowers the noise floor and improves the dynamics of the sound. The improvement in sound quality is so obvious that if you don’t hear it, your system is just too good, your location is just too perfect and you should send the GigaFOILv4 back for a refund. The experiences of audiophiles located in less densely populated areas with less EMI and more perfect in wall wiring than New York City and with higher end sound systems will be interesting to read as more people review the GigaFOILv4.

How Does the GigaFOIL work?

  • Insertion Loss: 100 dB from 10 kHz to 10 GHz
  • Fiber Optic Isolation Link (FOIL)Technology: The fiber optic isolation link (FOIL) technology maintains 100dB shielding integrity. The filter converts ONLY Ethernet packets, so there is no passband and no transmission of unwanted signals.
  • Network Performance Unaffected: The device will not increase network hop counts or degrade network performance, which is a common problem with standard signal line filters.

The dimensions of the GigaFOILv4 are 5.5 x 2.5 x 2.75. It certainly looks “industrial” with a steel construction and exposed welds. But it’s more about how it works, right?

The GigaFOILv4 is half the price of its predecessor and sells for $475.00. The latest version is not yet publicly available. According to DJM Electronics, “the GigaFOILv4-INLINE is currently undergoing regulatory review. It will be publicly available as soon as this is completed.” You can sign up to be notified when it is officially released via www.djmelectronics.com

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