Modem SMPS spec/upgrade question

[dgale]

Two questions really about replacing power supply to Xfinity Gateway Modem/Router -

1. Any benefit to replacing stock 12v/4.6a power supply with aftermarket such as ifi iPower SMPS? I have several external LPSUs throughout my system but wonder if wall to modem is worth an upgrade (As I wrote this, I imagine the answer is “of course “.

2. Stock SMPS for Gateway modem/router is 12v/4.6a ASAIK iFi and others only supply 12v/1.8 or 12v/2a Would reduced output spec like this be ok?

 

[ecwl]

In theory, no. I think John Swenson at Audiophile Style talked quite a bit about the issues with SMPS & Ethernet connections. Because of the way Ethernet cables are designed, if you're using unshielded CAT-5 cables from your router to your music streamer, the only noise that can go from the router to the music streamer should be high impedance ground current leakage noise which comes from the SMPS of the router (or iFi power SMPS) through the ethernet cable into the streamer and then leaks out through the SMPS/LPS of the streamer. The cheapest way to prevent that is to use a gadget like iFi Groundhog+ (or get somebody to build the cable for you) and ground the SMPS at the router to the power plug so that the noise can't get into the Ethernet cable. The most expensive way to deal with this would be to change the router's SMPS to LPS. But replacing one SMPS with another SMPS might change the amount of leakage noise but not necessarily solve the problem. Of course, if you use shielded CAT-5/6/7 cables, more noise can leak from your router to the streamer which would be a different issue.

That said, lots of people talk about lots of changes to the sound they hear when the switch things up. So your mileage might vary.

 

[Tuckers]

I have two media converter boxes that create a fiber bridge from my ethernet (Ethernet > Fiber > Ethernet), this goes into my streamer. I added LPS to them, with a better one on the end that goes to the streamer. This made a positive impact on my system. Next I have a switch upstairs that takes one ethernet from downstairs and splits it out into the upstairs, of which one goes to the media boxes I described above. I decided to try an LPS on this switch, skeptical that it would make a big impact on my system.

I was surprised to find that it did improve my system. Not a big difference, but definitely worth the money I put into it. The difference was smoother more liquid sound, deeper blacks/less noise, overall better flow.

I am considering getting an LPS for my Modem/Router too sometime, wondering if that will continue to provide rewards.

From my experience I'd recommend it as a possible small refinement to a system that is already pretty much there, if you have the funds.

These Gateway/Modem/Routers use a lot more power than an ethernet switch, hence the 4.6 amps of the SMPS, this means a relatively beefier LPS. Here's one that should do the job though. I would email Alvin on the site to confirm this though. I use this very same voltage/VA LPS on my Lumin U2 Mini and can recommend its acumen as a LPS.

LHY Audio (Jay's Audio) LPS80VA

 

[MaxwellsEq]

The very large switches in vast data centers have to be extremely efficient to minimise the very high cost of heat extraction. They are often based on advanced PWM type switching. I suspect that more than 99% of Ethernet packets in the world pass through devices powered by PSUs designed to minimise waste energy. If the PSUs in these data centers interfered with the accuracy and timing of the packets passing through them, the center designers would have to replace them.

In practice, assuming it is not faulty, a PSU will not change the characteristics of the packets passing through the device it powers. Over decades I've worked with a large number of Ethernet switch manufacturers with hundreds of model types over many generations of networking hardware. In all this time and experience, I've never encountered a PSU have any impact on Ethernet characteristic unless it was faulty.

 

[audiobomber]

Two questions really about replacing power supply to Xfinity Gateway Modem/Router -

1. Any benefit to replacing stock 12v/4.6a power supply with aftermarket such as ifi iPower SMPS? I have several external LPSUs throughout my system but wonder if wall to modem is worth an upgrade (As I wrote this, I imagine the answer is “of course “.

2. Stock SMPS for Gateway modem/router is 12v/4.6a ASAIK iFi and others only supply 12v/1.8 or 12v/2a Would reduced output spec like this be ok?

The iPower and iPower X do not have sufficient current for your router. You would need to go to the iPower Elite, which is 12V 4A. I am pretty confident you would hear an improvement with the Elite or a linear supply on your router.

 

[audiobomber]

In theory, no. I think John Swenson at Audiophile Style talked quite a bit about the issues with SMPS & Ethernet connections. Because of the way Ethernet cables are designed, if you're using unshielded CAT-5 cables from your router to your music streamer, the only noise that can go from the router to the music streamer should be high impedance ground current leakage noise which comes from the SMPS of the router (or iFi power SMPS) through the ethernet cable into the streamer and then leaks out through the SMPS/LPS of the streamer. The cheapest way to prevent that is to use a gadget like iFi Groundhog+ (or get somebody to build the cable for you) and ground the SMPS at the router to the power plug so that the noise can't get into the Ethernet cable. The most expensive way to deal with this would be to change the router's SMPS to LPS. But replacing one SMPS with another SMPS might change the amount of leakage noise but not necessarily solve the problem. Of course, if you use shielded CAT-5/6/7 cables, more noise can leak from your router to the streamer which would be a different issue.

That said, lots of people talk about lots of changes to the sound they hear when the switch things up. So your mileage might vary.

Here's a post where John discusses the SMPS grounding issue:

SMPS and grounding

Over the last month I have been performing extensive tests on leakage currents coming from SMPS power supplies. One of the most important results from this investigations is the makeup of this leakage current. Previously my understanding was that leakage current was mainly a low frequency phenoni...

audiophilestyle.com

The iPower Elite does not need any additional grounding, as it has a three prong AC plug which grounds the DC connector.

 

[audiobomber]

The very large switches in vast data centers have to be extremely efficient to minimise the very high cost of heat extraction. They are often based on advanced PWM type switching. I suspect that more than 99% of Ethernet packets in the world pass through devices powered by PSUs designed to minimise waste energy. If the PSUs in these data centers interfered with the accuracy and timing of the packets passing through them, the center designers would have to replace them.

In practice, assuming it is not faulty, a PSU will not change the characteristics of the packets passing through the device it powers. Over decades I've worked with a large number of Ethernet switch manufacturers with hundreds of model types over many generations of networking hardware. In all this time and experience, I've never encountered a PSU have any impact on Ethernet characteristic unless it was faulty.

A PSU change on a DAC, streamer, network switch, FMC or router, will definitely change the final sound quality. I have experienced this many times. EMI and RFI have no effect on the data in the network, but do affect the D to A conversion.

 

[MaxwellsEq]

A PSU change on a DAC, streamer, network switch, FMC or router, will definitely change the final sound quality. I have experienced this many times. EMI and RFI have no effect on the data in the network, but do affect the D to A conversion.

For the networking side, iperf3 would be able to help demonstrate the benefits.

 

[audiobomber]

For the networking side, iperf3 would be able to help demonstrate the benefits.

Perhaps, though I haven't seen much if any correlation between measurements and sound quality.

 

[MaxwellsEq]

Perhaps, though I haven't seen much if any correlation between measurements and sound quality.

Fair enough