AC Power

OP:

I’m of the school of thought that if you can’t hear it, you can’t hear it! So I don’t think that’s a bad arrangement in terms of audio.

However, in terms of surge vulnerability the modem is a concern. When I first moved to my current home in 2021 we had 4 homes with surge damage from the cable modem. Luckily everyone but me used Wifi, but I was OK. It’s not uncommon for a surge to enter a home through the coax cable and fry a number of Ethernet connected devices. The surge can enter via the coax and then find a path to ground via either the power supply or the Ethernet cables, if any. For these reasons I recommend:

1. Use a coax surge protector OUTSIDE thee home like this one.
2. Isolate your modem’s Ethernet connection using an isolator like this one or an Ethernet to fiber adapter
3. Put the Modem’s power supply outside of any surge protection used for sensitive audio equipment.

Of course, I may be more paranoid than most due to living in a lightning prone area. Some A’goners have never had lightning damage so they don’t understand the fuss. :D  Also, if all you use is Wifi you are less vulnerable to surges than those of use who hardwire their work PC's and HT systems.

PS - The issue is true for ANY copper based conductor, so cable TV, antennas, etc.

@erik_squires

• Lightning Arrestor for N-Type Antennas Surge Protector: Wouldn’t this work just as well inside of the house if inserted in-line before the modem? Ground it to the copper water pipes?
• EverStar MI-300 Ethernet Galvanic Isolator: There are many Ethernet isolators available - some using transformers (like in NA’s Muon Pro) and others using fiber optic isolation like in the GigaFOIL range of Ethernet filters (i.e., fiber optic isolation link = FOIL). The price of these filters varies significantly. Users report a similarly wide range of performance variations between the available options with (surprise!) the more expensive solutions typically reported to sound better. Any tips on how a buyer should know which to purchase?

Hey @mitch2

Wouldn’t this work just as well inside of the house if inserted in-line before the modem? Ground it to the copper water pipes?

Would you rather have a surge enter your home first, and then find a path to ground, or would you rather have it find a path to ground outside?  By law there should be an external grounding block which is the ideal place to put one of these.  Obviously if you are an apartment dweller you can't do that, so you do the best you can.

There are many Ethernet isolators available - some using transformers (like in NA’s Muon Pro) and others using fiber optic isolation like in the GigaFOIL range of Ethernet filters (i.e., fiber optic isolation link = FOIL). The price of these filters varies significantly.

Convenience and cost matter. The issue with isolators marketed to audio consumers is that they are not tested the same way that isolators for patient care devices are. The latter are tested to ensure 4kV of isolation from input to output, so if using an in-line Ethernet isolator make sure it’s tested to IEC 60601 (I think there’s a UL equivalent). Everstar is among the most affordable.

Between my modem and router I use Ethernet to Fiber isolators with a 1m air gap. At the end of runs from there to my home office or HT I use the Everstar isolators. About the same price per use. The fiber adapters run $20 each, plus the fiber optic cable.

Based on the latest research, avoid any Ethernet isolator/surge protector that grounds the signal, as those can be more dangerous. Since I don’t know which is which I never use the built-in isolators in power strips.

@mitch2 

Forgot to mention, copper pipes haven't been considered good grounds for many years.  In addition to not being that great to begin with the potential use of PVC pipes to break the connection to ground is a problem.  Even if it's copper now, the next plumbing upgrade may break it.

Point is, no, grounding to a copper water pipe is no longer considered best practice.  You want to run a copper wire and bond it to your house ground.  The outside grounding block, which your cable installers put in already has this.

@erik_squires Thanks! I somewhat misspoke. It is a mesh router with an Ethernet backbone, not a modem. My (fiber) modem & main router are downstairs. I also have my HT sub plugged into my secondary power.
I am less concerned (famous last words) with a lightning strike as my house is surrounded by trees twice the height of my house. I am much more concerned with a tree falling on my house. 😒
I will order the Furman PST-8D for only $20 more than the standard PST-8. It will provide conditioned power via 2 isolated power banks, not only to isolating my sub from digital, but provides future protection as my TT may move there in the future.

Please let me know if I have any flaws in my logic. Thanks again!