DJM Electronics GigaFOILv4 – INLINE Ethernet filter

and the winner is...

Device Type: Inline Ethernet Filter
Input: Ethernet
Output: Ethernet
Dimensions: 5.5 x 2.5 x 2.75"
Weight: about as much as a brick
Availability: Direct online
Price: $475.00
See description

News Flash: Ethernet noise FOILed!

For readers who have been around since 2015, you may recall my review of the DJM Electronics GigaFOILv3 Ethernet Filter wherein I said:

The first change I made was to take the GigaFOILv3 out of the system. What I heard was a less refined sound, especially in the upper registers. This was a subtle change, and certainly not worth a grand, but the GigaFOILv3 clearly made my music sound less digital, less harsh, and more natural. While A/Bing is all well and good, having the GigaFOILv3 in my system for weeks was a better gauge of its effects since I very easily noticed a more relaxed and engaging sound over time.
You may also recall that this version of the GigaFOIL under review oh so many years ago was sent to the barn as proof of concept since the GigaFOILv3 was overkill for hi-fi applications and priced at 1,000 smackers. If it worked, and it did, Steve would work on a lower-priced version.

Here's what DJM's Steve McNally said about that:

"I’m confident we could offer substantially better conducted and radiated EMI performance over any existing fiber solution. And it would be simple and elegant - probably about the size of a deck of cards with a single AC adapter."
Today, I'm here to talk about the new GigaFOILv4 the proof from the concept.

If you checked out my In Barn post about the v4, you'll recall how it uses, as do all of the DJM FOIL Ethernet filters, a fiber link inside. Why? Here's DJM:

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 (ie “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.

As you can see, the DJM Electronics GigaFOILv4 is designed to filter out noise from an Ethernet link. You can also see that the GigaFOILv4 has an industrial look, welds and all (think heavy metal), something I very much enjoy (YMMV) [footnote 1]. Looks aside, I have found that isolating my hi-fi from Ethernet's electrical noise using fiber media converters and AudioQuest Ethernet cables makes my music sound better. The big question today being—does the GigaFOILv4 make my music sound even better? Betterer?

Here's what I did.

  • compared the GigaFOILv4 to my TP-LINK MC200CM Gigabit Media Converters using my dCS Network Bridge into my totaldac D1-seven (via AES)
  • compared the GigaFOILv4 to my TP-LINK MC200CM Gigabit Media Converters using the review sample dCS Rossini (the Rossini has an Ethernet input)
  • compared the GigaFOILv4 to my TP-LINK MC200CM Gigabit Media Converters using my microRendu into the totaldac (via USB)
  • compare all of these with a straight run to the router (no filter or converter)
  • left the GigaFOILv4 in my system for weeks then compared it to the TP-LINK
Let's get the obvious (for those with experience filtering noise out of their Ethernet hi-fi link) out of the way—the straight Ethernet run from router to endpoint (dCS Network Bridge, dCS Rossini, microRendu) sounded the worse. My notes, although brief, tell the entire story, "glare + metallic sheen". This coloring of the sound was present in all three scenarios although the microRendu offered the most pronounced difference/degradation.

With the TP-LINKs back in the picture, which is my usual setup, music sounded softer with less glare and offered a richer tonal palette. Again, this move from metallic sheen to a more natural sound was consistent among endpoints.

Then the GigaFOILv4 stepped in and wiped the floor with the TP-LINKs. OK, I am not talking about the kind of difference you can hear between sending the totaldac bits from the dCS versus the microRendu, but I am talking about a clear and consistent improvement, mainly in terms of micro detail which translates into a more coherent sound image coupled with a more natural presentation within it. Think more fluid, less digital sounding.

Acoustic instruments really appreciated the GigaFOILv4's filtering as they sang out with truer tone. Piano, some digital can dismantle a piano faster than you can say 'bits are bits', gained more body, more spatial clarity, and more realistic attack and decay. Paino became more piano-like with the GigaFOILv4 in the picture.

As I said, these changes were not on the level of changing a component but I welcomed the improvements the GigaFOILv4 made in every connectivity scenario I ran it through, which can be summed up by saying music sounds more natural, more relaxed, and less digital.

Let's face it—no one wants their music to sound digital. I sure don't. Digital sound makes me uptight or worse it can make me want to stop listening to music. Having the DJM Electronics GigaFOILv4 – INLINE Ethernet filter in line in my system made the greatest impact over time as opposed to A/Bing (I don't X). I would bet money that most people spending a few seconds A/Bing bits of music over and over will not hear a difference. As a matter of fact, if you want to convince yourself that something doesn't offer any difference to the sound of a hi-fi, just keep A/Bing until all differences go away. If you're pressed for time, throw in an X and speed everything up.

Here's what I recommend—if the device(s) you use to convert digital to analog is/are part of a network and that device costs at least 10 times the price of the GigaFOILv4 – INLINE Ethernet filter, try one. Based on my experience doing so will chip away another layer of digital's unwanted haze.

1. I also enjoy, and enjoy may not be a strong enough word, replacing more (2x TP-LINK, fiber cable, and their associated power supplies) with less (a chunk of a steel box and its lone power supply) while getting more of what I want (keep reading).

Also in-use during the GigaFOILv4 review: TP-LINK MC200CM Gigabit Media Converters, microRendu, dCS Rossini

Associated Equipment

dmormerod's picture

I wonder how much difference there would be if you used better quality media converters or a switch with Fiber built in?

Stephen Dupont's picture

Michael- based on the first picture, it appears you're using two different power supplies on the TP Link FMCs. can you clarify, and did you use the stock PS with the GF4?

Michael Lavorgna's picture iFi supply for the TP Link on the hi-fi side. I also used the stock supply with the GF4.
Michael Lavorgna's picture
"...the power adapter provided with the filter is a linear power supply and we use a linear voltage regulator on the circuit cards. Also, the board layout is specifically designed to minimize as much as possible the noise generated on the card..."
Matias's picture

Any difference in using different input cables?

beaur's picture

I just cut out all the extra parts and use fiber from converter to DAC (Bel Canto 3.5). Wish more manufacturers would use fiber directly on their DACs, to me it does sound better and I definitely don’t have RFI issues over the 30 feet or so I have had between my computer and DAC.

Lifer's picture

I communicated with DJM Electronics and they will get back with me when the device is available.

insertusernamehere's picture

... but as high as you (Mr. Lavorgna) were on the BACCH technology only a short while ago, there is no mention of it in your system in any of your latest reviews (this one included). Does that mean that it's no longer in your system? I know reviewers tend not to like us to "read between the lines" (because if they'd have meant it, they'd have written it), but might we infer the BACCH's absence means that you didn't find its contribution to your enjoyment sufficient to justify its price? You've made many changes to your system (relatively) lately, including the Leben, the DCS and (less recently) the totaldac. So, after so many plaudits, the BACCH seems conspicuous by its ongoing absence....

Michael Lavorgna's picture
You can see my entire system listing if you follow the "Associated Equipment "link that's included at the bottom of every review.
insertusernamehere's picture


Michael Lavorgna's picture
...that part of the reason is I do not see Bacch as being a good tool to include in a reviewer's system. It adds an element to reproduction that most people will not hear.
insertusernamehere's picture

Not being a reviewer, I like the idea of the BACCH technology very much and I'm saving up to buy one now--but will only pull the trigger after I get a chance to listen to a BACCH system myself. That said, I'm trying to do as much research as possible beforehand and am very sensitive to what others' experiences have been. In that light, your response and clarification are much appreciated.

Greyfossil's picture

The 10x price comment was helpful. Its interesting but I'm using Auralic stuff that doesn't cost that much so I'll stick with the TP-Link. Like one of your other subscribers, I only have one box to contend with as I run a 30ft Fibre cable from the basement server to the room with music.

Michael Lavorgna's picture
I'm pleased to hear that the 10x reference was helpful.


PAR's picture

At the time of the review and at the time of my writing some days later this is only a prototype " currently undergoing regulatory review" according to DJM's own website. There is no guarantee therefore that the final product will resemble the item reviewed here in all ways.

The review policy of the associated publication" Stereophile" would not allow a review of any product at this stage of its development.

Absolute Zero's picture

an improvement other than someone says it does? I know 60hz AC components can make it over the wire. Would this stop it?

Also what scenario is going through this expense in a home environment be better than WiFi. I put in $200 of WiFi Router/ USB 3.0 Adapter and routinely get 40/MB second and less than 2ms ping very consistently.

calloway's picture are saying that the filter is positioned after the router with the ethernet cable going to this case...Lumin A1 player..So ethernet cable from router to filter and the current ethernet cable from filter to Lumin..?