Ethernet to Fiber media converters

(Magnus) #82

Cheers, I also feel that going ROCK + NUC is in one way nice to get audio software in its own computer, but not worth it from a pure SQ point of view. Upgrading the FMC sounds interesting though, even without this upgrade a better power gives a slight increase in SQ (I currently run my DAC-side FMC on 8*1.2 rechargeable batteries, they last several days).

Later on, I plan to upgrade both my DAC and transport, maybe to the new MyTek Brooklyn Bridge, so I try to stay away from upgrades that won’t benefit that future upgrade for now.

I have the 100Mb TP-Link, is that the same one that Sotm upgraded for you?

(Sean) #83

Yep the 100M model is the one they upgraded for me. Some of the thinking is the optical-to-copper conversion itself (the DAC side FMC) may be a noisy process, so it’s possible this is how the upgrade helped… SQ became smoother (for me). Who knows.

As mentioned the upgrade allowed the FMC’s to be 5Vdc powered, so that made it easy to power the downstream one with a battery for example… (for ultra critical listening).


Did you send the 100Ms off to Korea Sean?

Or are you there already?

(Sean) #85

Hi gasman

Due to the postage costs sending to Korea, it was much cheaper for SoTM to buy the same model locally. I even asked them to buy the appropriate fiber cable so they could test everything (because they didn’t have any fiber cable themselves at the time). So they bought everything, modified the FMC’s and tested everything properly before shipping the tested FMC’s + fiber cable to me.

They gave me the costs all upfront and I paid upfront.

I think I was the first to ask them to mod FMC’s and they’ve done a few since. But SoTM have been doing mods of all sorts of things for people for many years, so that’s where I got the idea to ask them.

Btw: Uptone Audio will have their EtherRegen coming. It will feature a fiber port…

If you could find a compatible fiber switch, then you could just use a single Uptone EtherRegen for the DAC side, using it’s single fiber port. If the optical-to-copper conversion process is indeed noisy (I don’t know) then having the EtherRegen on the DAC/streamer side connection will probably be much lower noise than even my modded SoTM’s (knowing the work of John Swenson).

Or if money were no object- get a pair of these, connect each via their fiber port, just like a pair of FMC’s. From what I read though they are hinting the copper isolation will be very effective alone - moreso than typical transformers in ethernet cables/ports. They are using different magnetics/transformers. Read more below:

Having said that, I’m very happy with my modded TP-Link FMC’s.


Many thanks Sean

Have emailed SoTM as well as a local guy to see what comes of it, but will nonetheless await eagerly Mr Swenson’s latest creation


I had been using the TPLink converters
I now use the 10Gtek ones. I think they are much quieter…

(Magnus) #88

I think all ports are Ethernet on that one, the fiber part is some in-between thing (cage?):

  • One end will have four Gigabit “dirty-side” RJ45 Ethernet “input” jacks
  • Other end will have an SFP Fiber Ethernet cage, an LED, a DC input jack, and the one very special, clean and highly isolated Ethernet “output” jack (which is 10/1000Mb, not Gigabit)

So in other words, if I understand correctly, it will be a 5 port switch, with one clean HiFi output that uses fiber conversion internally. I would also guess it has 2 DC powers, the one on the dirty side won’t benefit (much) from better power.

Sounds interesting anyway!

(Magnus) #89

Or maybe both an clean ethernet and SFP, which I would guess is easy to do if you do fiber conversion inside.

(Sean) #90

It’s an SFP cage - but if you add your own gigabit SFP module (cheap and easy enough to do…) you then have a fiber port… This is the point of the SFP cage - to allow people to add their own SFP module (see below posts).

The only “clean” port is copper (only one port) and that’s what you connect to your DAC/streamer.

Whether the specially chosen/designed copper isolation is as effective with isolating the upstream copper connection VS running fiber to it… we’ll have to wait and see.

Nothing beats optical for ethernet isolation (I guess we can say wireless but that’s another topic hehe) but Uptone are clearly hoping/planning for the chosen magnetics/transformer/PHY to come close. We’ll have to wait and see.

(Sean) #91

Isolation (blocking leakage currents) is only one of the things they are tackling. Anyone with a pair of FMC’s and a battery to power the last FMC can do the same (like I have) to 100% block leakage currents and mains RF.

The other things they are doing with the ‘clean’ ethernet port are maximising signal integrity to the DAC/streamer and the ‘clock blocking’ thing. Don’t ask me about the latter. John S is still in research mode himself.

(Magnus) #92

My guess is that they use an internal fiber conversion for isolation, and combine it with a good clock and signal generator. And then. since they already have a fiber signal internally, it was easy and cheap to make it available as a SFP port.

(Sean) #93

I’m 99.99% sure it won’t be optocouplers. John has said in past discussions about digital isolators (before EtherREGEN even had a name) that his favourite type of digital isolators are Giant MagnetoResistive (GMR)…

I think we’re gonna have to nickname him Magneto :grin:

I’m only guessing of course.

Plus there is this comment:
“It is just that the is only one super-special port (where a lot of extra chips and $ are going) which will be highly isolated—using techniques that have not previously be applied to Ethernet.”

Optical isolation has already been applied to ethernet. FMC’s, switches with SFP ports… and see the GigaFOIL V4–-inline

(Hans Bogaert) #94

I have isolated direct electrical ethernet connection from my network entering my DAC by converting electric ethernet to optical and back. That blocks all electrical noise on my network from entering my DAC.
I used simple cheap components ( total cost 30 $) . The impact it made on the sound quality is really amazing.

(Sean) #95

Great stuff Hans. Yes this is indeed what this very thread is about.

I have a pair of TP-Link MC110CS fiber converters. Useful indeed.

(Larry Post) #96

Except for the last power supply that powers the transceiver closest to your DAC. That’s the important one.

I too have found modest improvement with inexpensive fast Ethernet transceivers. My DAC is already quite immune but this helps nonetheless.

I should add I don’t have Ethernet into my DAC. Rather Ethernet into my music server then I2S into DAC.

(Hans Bogaert) #97


You are correct the last power supply will have influence.
At the moment I just kept it simple. the 2 converters came with a cheap switched mode power supply and that’s how it’s running at the moment.
Today I’m still overwhelmed by the impact the isolating of the noise from the switches has on my DAC.
I’m certain that removing the last power supply with a battery or linear power supply will again be a step up but a minor small step up. That’s just as feeling I have, I might be up for a surprise if I do replace that power supply :slight_smile:

(Magnus) #98

That’s exactly my experience, the fiber converters did a noticeable improvement, running the last converter on battery took it up another step (but a smaller step). But since the converters have switched voltage regulators inside, that’s to be expected.

@Sean2016 had his last converter upgraded to using linear power regulators, I am thinking about doing the same. Its one of these future proof upgrades after all (no matter DAC/streamer/transport upgrades, it will still be in play).


Here is what Alex of Uptone said when I asked him what the benefit of his upcoming etherRegen is compared to Fiber Media Converters / Isolation:

While a fiber media converter will provide complete galvanic isolation from the upstream connections, that is really about all it accomplishes.

There is still much to consider from the fiber back to copper Ethernet and on into whatever critical DAC-connected device you are feeding. The FMCs we have looked at are filled with cheap noisy regulators, they do nothing to isolate from the processing of the SFP-caged module, there is no isolation after the switch chip (or whatever form of Ethernet processor they happen to employ), no improvement to clocking, and no focus on output signal integrity.

EtherREGEN does focus on all those things, plus offers one fiber media port and 4 Gigabit copper ports—in addition to our super-optimized 10/100 “output” port.

So we will look forward to reports comparing our switch to FMCs. We honestly do not know how significant the difference will be for how many of you. But my personal experience with FMCs versus even the special Cisco Catalyst suggests many folks are in for a treat.

(Hans Bogaert) #100

Looks like they are confident that their product is superior and I have no doubt that that’s the case.

Question that comes to mind is how much will it cost versus how much improvement it will provide compared to FMC’s. I’ve spend 30$ and in return it provided a serious improvement for my DAC / audio system.

My DAC is 2 years old and with the speed new models are hitting the market, in a year or so it’s called " vintage" equipment. For me ,the solution I have in place with this DAC, I’m happy.
There’s always room for improvement however I’m not sure if spending more money on the ethernet port with the DAC I have would be the right way to go…

What I found interesting is that before installing the FMC the difference between DSF and PCM files was huge.
DSF was much better and pleasant to listen to.
I did a test where I converted a PCM file to DSD and it really sounded better.
That doesn’t make sense unless there’s something on the decoding side that has an impact.

Now with the FMC installed the sound quality improvement is significant for PCM files while DSD files are slightly better. In fact they are now pretty close. DSD is still a bit better but not by far.
Before the FMC installed ,playing MP3 files and internet radio was horrible , not even background quality.
Now with the FMC installed it’s still not great but as background… yes it’s ok
These things I find interesting and if the decoding is making so much difference than that might be in my setup a good new focus point :slight_smile:

(Magnus) #101

Yet again same experience as I had. In fact, since I started using FMC I prefer PCM unless the source is DSD (that is, I don’t up-sample PCM to DSD, like I did before). Someone more tech-savy then me might have an explanation to this.