Improving Comcast modem signal

It's actually on a separate circuit and besides my dedicated listening studio is grounded with a wonderful grounding device. Noise floor is basically non-existent.  

Reading this reminded me of what Mike over at headquarteraudio does:

Some here are gonna go ballistic and say it's overkill but it's just only another perspective to be considered.

All the best,
Nonoise

The pic I posted of the Gateway evaporated.  Here's another.

But now I can't find one with the external power supply that's bundled with it, so this is what an after-market one looks like.

I wonder if it's any better than the original.

FWIW, I spent half an hour this morning in the weeds of reviews on Amazon: Netgear, Motorola, Arris, etc.  And while 85% were happy campers, it seemed like every model had its problems.

Does this mean the Verizon fiber optic system is better than Comcast cable for digital systems? 

I chose to supply my own modem and router with my internet provider. I did place low noise power supplies on both the modem and router--I used iFi power supplies. I didn’t hear a difference when I placed them into the chain. However, I haven’t tried removing them from the chain, and sometimes I only hear a difference after removing something. Also, my total (retail) system cost was about 2k at the time I introduced iFi PSs to the modem and router, and now my total retail system value is about 5k. It’s possible that my system wasn’t resolving enough at the time to hear a difference, but that it might be now.

Like you, I’m looking for upstream solutions to improve sound quality. Here’s the short list of obvious audible upstream improvements I’ve had: DAC upgrade, streamer upgrade, reclocker/master clock, power cables/supplies for the DAC/streamer/reclocker.

I am currently flirting with upsampling, upgrading coax internet cabling to solid core copper coax, and converting the internet coax cable to optical right before the streamer. All of these projects are still TBD. I’m anticipating a nice improvement from converting to optical. My recommendation to you would be to look at optical conversion first, if you haven’t already. Your EtherRegen switch has an optical-in. You don’t necessarily have to run optical through your walls to start. You can start by just converting to optical right before the internet enters the EtherRegen. That way you can play with single-mode and multi-mode SFP transceivers and optical cable to see if one option sounds better than the other. You can also control for media converters (by EtherRegen or Sonore e.g.) and their power supplies. There may also be audio-grade SFP transceivers and optical internet cable I don’t know about.

One thing I’ve thought about, but haven’t yet tried, is breaking down the router into its separate components. As you may know, ISPs will supply consumers with all-in-one modem-routers. Lay people who tinker with their home network will usually get as far as breaking down the AIO modem-router into into separate modem and router. But, the router itself can be broken down into another 3 components: routing, switching, and wifi access points. The benefit to breaking these down is network performance--an old computer with routing software installed is going to outperform an off-the-self router from Best Buy--and components can be upgraded separately. Now that consumer mesh router systems are starting to cost upwards of $700, separating out routing from access point management might make sense from a cost perspective too. Anyway, I don’t know of any audiophiles exploring possible sound quality improvements with commercial-grade or DYI networking solutions. But you could create an amazing home network in the process at least. 

I have just started to play with Roon Cores/music servers. It seems to me that in as far as the a music stream passes through a router, access point, or switch, that those components may audibly affect the stream.