Stereo Times 2024 MOST WANTED COMPONENTS List

There’s a difference between making a mistake in a post on a forum and committing a bunch of grammatical errors and misspellings in a professional, published review or article.

AARDVARK ETHERNET ISOLATOR

I took a shallow dive into this one the other day. It appears to be a basic LAN electromagnetic voltage transformer module, the purpose of which is to provide electrical isolation, improve signal integrity, and minimize issues like electromagnetic interference (EMI). That all sounds positive. The module costs about $10, or less.

Others offer similar solutions such as the English Electric EE1 Network Isolator, for $295, the Crux Audio LAN Noise Filter, currently priced at $250 or, at an even lower price, the EverStar MI-300 Ethernet Galvanic Isolator for only $87. In the other direction is CAD’s Ethernet Control for $1,250. Finally, there are options available from manufacturers serving the world of computer networking, such as emo System’s EMOSAFE EN-70HD ($172).

I have no idea what makes one option better than the others, especially since they all seem to be based on a filter module costing about $10, but if you buy into audio reviews, Roy Gregory, in this article at Gy8, (conveniently and predictably) explains that the performance gets better as the price goes up, from the English Electric EE1 (good) to the Aardvark Ethernet Isolator (better) to the CAD’s Ethernet Control (best). Setting aside the perceived hierarchy, I am curious how the improvements can be so precisely graded for a product category that many believe provides subtle differences/improvements, if any. I am curious, but also wonder what these might do for my system that already has two optical isolation breaks, including a fiber optic line covering the last 45 feet directly into my streamer. I guess I could try installing one on the Ethernet cable coming out of my router.

@mitch2 - I will get one when I see one in use at Google data center :-) For some reason I am pretty sure they don’t use "isolators" in their net connections while handling your FLAC files and streams...

@mikhailark - Maybe some of the network savvy folks here can weigh in but my impression in reading about these isolators is that they are indeed in use in certain networking situations, particularly related to the medical field.  This below is from emo Systems:

EMOSAFE Network Isolators are used in copper-based network connections in private, public, and commercial sectors.

They protect connected equipment against extraneous voltage sources and overvoltage, which can arise from installation errors, aging components, or moisture at the network interface. They attenuate low-frequency signal components and thus protect connected equipment from ground loops and other problems.
Overvoltages induced by lightning strike and switching processes can be inductively coupled into network lines. Such overvoltages can be restrained by Network Isolators.

EMOSAFE Network Isolators are primarily used in medical applications.
They conform to the high requirements which IEC 60601-1 places upon galvanic isolation devices in the medical field.

The other thing I am curious about is, whether most/all component devices that interface with an RJ-45 Ethernet cable already include transformer isolation.  IOW, are these commercial "audiophile" filter devices fixing a problem not in evidence and, if so, how can they affect the sound to the extent as reported by the reviewers?  I found this:

A typical Ethernet port includes isolation transformers, common mode chokes and port termination as shown in Figure 1. The transformers have a minimum isolation rating of 1500 VRMS (2.1kV) as required by the IEEE 802.3 standard for Ethernet interfaces. Common mode chokes are often integrated with the isolation transformers and serve to reduce EMI emissions. Ethernet ports are commonly terminated using the “Bob Smith” technique. This termination uses a 75 Ohm resistor for a common mode impedance match at each signal pair, collectively connected via a high voltage 1000pF capacitor to chassis ground. The purpose of this termination is a further reduction in common mode emissions.

Figure 1 – Ethernet Interface Components © Semtech Corporation 2020