Improving Comcast modem signal

The one that I have has an internal power supply. Sksos, what grounding device are you using?

@chungjh yes my modem/router has the internal power supply. As for the grounding box, since I'm a dealer I don't promote it on this site, feel free to PM me.

Thanks. I don't have any noise now with 93% efficient speakers. No mater where I plug mine in the with an external PS it has a ground loop issue. The only piece of gear that does that. It's less than a year old. Great transfer speeds with Cat 8 from Cat 5. The GL eliminator shut the stupid thing right up. 

I've tried 3 of the neighbors PS too. Same thing. You should hear it with Klipsch 103s they will run you out of the room. Neighbors rig.. GL eliminator fixed it right up.

Thanks Ay..

Regards

I've used my own Arris modems with Comcast/Xfinity since 2014.  They work fine.  If there is a problem, Xfinity will say it's your modem every time.  So far, it's never been the modem - instead an Xfinity service problem that is solved on their end within some period of time.  If you need  tech onsite, they might charge for that.  I've spent $325 on 3 modems 7 years (I like to keep them up to date), so even with a tech charge, I would be many $$ ahead.  Currently using an SB8200.  No GL, no LPS.

The Internet and the router are digital signal things. Am I wrong to think they don't introduce noise into the bitstream?

Now if a power supply is near some analog device in your setup, the solution would seem to be putting some distance between them or a similar action.

We never had Comcast. On AT&T and now our superior local ISP, Sonic Fiber, I have used a cheap TP-Link Archer 8 modem. It works fine. AT&T requires its gateway device, so my router was behind it as an access point. Sonic lets customers connect their own router to its ONT gateway.