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LPS for Optical Network Terminal (ONT)


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We have fiber coming into our home with a Nokia ONT/Router combo and I want to add a LPS for streaming. The ONT presently has a wall wart providing  12V, 3A to power it.  Below are pictures of the wall wart and the ONT connector at the other end.  Can I  just splice in a standard   US NEMA   plug to the existing wire for connection to a LPS, or, do I need to purchase some specific wire  (which already has an ONT connector like in my picture below) to go  between a LPS and the ONT ? 

I know this sounds extremely simple but I just want to make sure the rewiring doesn't screw things up due to my overlooking something obvious.  I can be very good at overlooking the obvious   😥

Thanks for any insight,

Bruce

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Hi Bob.  I'll take apart the wall wart and look at the wiring inside. Maybe I can splice in a  barrel or XLR connector as Mitch2 suggested. I will post pics of the internal wiring once I open it up and let you know how it works. Wish me luck.....

Bruce

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@GdnrBob  I am holding off on the LPS right now and I am using a "ferrite ring toroid"  (doughnut shaped iron)  that I bought from Palomar Engineers last year. I have a very low noise floor as far as I can tell considering my diminished hearing with age. So, if the DACs I audition don't reveal background noise I'll just let it be. 

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no need to obsess over that Bruce.  Like you said, get it up and running and go from there.  I have a couple of LPS units that are very good and I put my modem and router on those units and they plug into an unused Niagara 1000 I had after I got the 3000.  I hear a small difference. Also, the router and modem through the 1000 are on their own dedicated circuit that I just happened to have had run when they built my place (it was a free upgrade to get two dedicated circuits in a separate box and individual grounds outside as the electricians and I had a bet over the difference in sound they make).  They lost and I won.  Let her ride and enjoy the music.  Play time can come afterwards, but I bet you won't need to do anything else.  Put your money into the best DAC you can afford before thinking about any tweaks.  That includes cabling etc...  

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On 2/23/2024 at 9:55 AM, Bruskie said:

@GdnrBob  I am holding off on the LPS right now and I am using a "ferrite ring toroid"  (doughnut shaped iron)  that I bought from Palomar Engineers last year. I have a very low noise floor as far as I can tell considering my diminished hearing with age. So, if the DACs I audition don't reveal background noise I'll just let it be. 

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Doesn’t one want to run one wire in one direction , and the other one in the opposite direction?
That kind of involves cutting a wire, or some IQ test to Houdini the thing in the right twist.

Basically a twisted pair has little magnetic field as they cancel, so I think one wants the magnetic field to add, in order to impede or choke the high frequencies?

Edited by Holmz
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@Holmz  Thanks for the tip.

I know it's not a cure all but I am trying to reduce any EMI coming in from the mains,  and any ripple current created by the SMPS,  from entering the ONT. I thought that an inductor would reduce some EMI through back EMFs???  I am not attempting to minimize any EMF being radiated from the SMPS cord itself, although that is another consideration. I understand basic E&M but am not in any way knowledgeable in modern electronics so I'm sure I am overlooking quite a bit.

I wish I knew how to make the connection (on the ONT) work with a cord from an LPS. It's easy to find an LPS that puts out 12V/3A , but the connection is my foil

Bruce

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Guys, I'm telling you that the WAversa EXT device (any of them) works better than all the optical devices I've tried. I even have daisy chained their least expensive one with my Ref one and it made an even larger difference.  It does much more than what optical does.  Just ask a few of the guys on the board who are using one.  It's not magic as the company has done extensive research on this.  If you have interest, just PM me.  I am friends with the distributor, but only because he's a good guy.  I bought them because they do so much for the price.

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On 2/28/2024 at 10:03 PM, Bruskie said:

@Holmz  Thanks for the tip.

I know it's not a cure all but I am trying to reduce any EMI coming in from the mains,  and any ripple current created by the SMPS,  from entering the ONT. I thought that an inductor would reduce some EMI through back EMFs???  I am not attempting to minimize any EMF being radiated from the SMPS cord itself, although that is another consideration. I understand basic E&M but am not in any way knowledgeable in modern electronics so I'm sure I am overlooking quite a bit.

I wish I knew how to make the connection (on the ONT) work with a cord from an LPS. It's easy to find an LPS that puts out 12V/3A , but the connection is my foil

Bruce

I don’t know a lot about Nokia ONTs (I worked for their competition…), but I did find a source for power cables.

Power Cables - Maybe

Now, I have to offer the same spiel I did at work on this subject.

Not all switching supplies are bad or noisy.  Aside from efficiency, they offer the possibility for reduced capacitance between the windings on the transformer, which could reduce the common mode current coupling.  That’s a good thing, for reasons I’ve ranted about here previously.  Of course, that presumes that the switching supply design indeed includes a transformer.  Transformers cost money, take up pcb space, and add to the shipping cost.  So, lots of companies use topologies that don’t use transformers.  Really good switching supplies do not come cheaply.  ONTs use cheap supplies.

Of course, really good “linear” power supplies (they are hardly linear) don’t come cheaply either.

If you want to find out if your supply is degrading your audio system, find a UPS or battery power system for your ONT and see if disconnecting from the power line helps or not.  That’d kill the common mode current loop, for sure - nothing beats no connection at all.  If not, the supply may not be a problem.  Or, the supply could be generating differential mode noise, which can be improved with a different kind of filter or a better supply.

What you did with the ferrite toroid on the supply power cord is to increase the common mode impedance of the power supply relative to the system overall.  At least over the frequency band where the ferrite is effective.  That’s normally a very good thing, but with a single ferrite core of unknown provenance, the results might be less than what you want.

BTW, devices like the Waversa are also common mode chokes.  They just are in series with the data line instead of the power lines.  But, the data lines and the power lines are all part of the same common mode current loop.  Break the loop where you can.

This entire subject really is fundamental, which does not imply simple or obvious.  Nor are the solutions easy.  It’s like carbon fiber and balsa speaker cones, time alignment, cabinets within cabinets, and so on.  The effects are obvious and conceptually easy.  But, finding viable design solutions is challenging.  It’s way easier to just wave your arms and declare that the problems the inventions solve don’t really matter.

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@BKDad  Thank you for taking the time to give me such detailed feedback. It helps so much when forum members freely give themselves so we can all further our understanding and enjoyment of this hobby. I will be doing some reading into this, thanks again.

Bruce

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Bk, are you a physicist or engineer? That first link brought back memories when I scrolled to Maxwells Eqs.  Makes me realize how much I forgot.  

Your check is in the mail.... 😂

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I am now a full time employee of a woman owned home enterprise.  Up until about a year ago, I split my time between the present gig and a career as an engineering physicist.  (Modern name for a physics major who preferred lab work, so he worked as an engineer.)

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I’d like to add something here.

I offer these links to articles not to impress anybody (fat chance of that) but to make it easier for everyone who is curious at a deeper level to read what experts think on the subject.  Of course, nobody really needs to read this stuff or understand it unless they are the ones designing and manufacturing the equipment.  

My own opinion is that audio enthusiasts should decide what is best based on how it sounds to them and the other household members who will also be listening.  But, just like car or art enthusiasts often like to know what is under the hood, a certain portion of the audio crowd likes to understand how their gear works and what they can do to get the best results.  Marketing collateral isn’t always the best way to get that understanding, although there are obvious exceptions to that.  I like to support companies who are straight shooters in that regard.

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I've love reading your poss from day one, because you are honest.  My daughter majored in physics and entrepreneurship (I have no idea how she did both in 4.5 years either).  I love listening to her talk as she's similar to you. Just a straight shooter, but room for her creative brain (artist, cook, athlete etc..).  I'll let Bruce pay you though if that's ok. 😉 

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