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Matrix Audio SI-1 Network Isolator

A recent discussion on the value of network switches by @fire_water  rekindled my curiosity about revisiting optical isolation. As someone who leans toward minimalism, a single-box optical isolator was the prime draw and to see if newer devices offering further improvements over my existing optical isolator. 

For context, my front end is built around 3 chassis Merging Technologies +PLAYER / Merging Technologies +CLOCK / Merging Technologies +POWER which is already extremely low noise, highly resolving, and very “studio honest,” reflecting its roots in professional high-resolution recording and editing. It doesn’t gloss over upstream shortcomings—if anything, it exposes them. As a result, any change ahead of it is easy to evaluate.

To be fair, my existing Telegärtner OPTO BRIDGE 1000M already performs very well—delivering a cleaner background, lower noise, and solid isolation. No complaints there except it is powered by an external LHY linear power supply…extra cables plus more real estate :-) 

So how does the SI-1 compare?

In my system, the SI-1 builds on Opto Bridge foundation with:

  • A further reduction in noise floor
  • Greater image density and depth
  • Improved microdynamics and sense of flow
  • A more natural tonal presentation without sacrificing resolution

The biggest difference?
With the Telegärtner, the presentation was clean and relaxed.
With the SI-1, it becomes more organic, fluid, and musically coherent.

My take:
Telegärtner = excellent isolation
SI-1 = isolation plus signal refinement (regeneration) by breaking ground noise and eliminating EMI/RFI riding on Ethernet. 

In a highly resolving system, that extra layer makes a meaningful difference.

Here’s the rub guys, not every system truly benefits from an audiophile Ethernet switch or an overbuilt router. That’s been my experience after introducing optical isolation into the chain. Once I did, even a high-quality switch like the Telegärtner M12 Gold Switch became redundant.

IMHO, optical isolation is essential for any serious streaming setup. The SI-1 doesn’t feel like a tweak, it comes across as a final-stage refinement, allowing your streamer to perform at its full potential and reveal what it’s genuinely capable of.

Here is my signal chain, 

Apple Router →  SI-1 → Streamer (Merging stack) using a pair of FTA Métis LAN cables. 

https://www.matrix-digi.com/product/125/SI-1

lalitk
phusis's avatar
phusis
1,392 posts
 

@mammothguy54 --

Thanks for your detailed impressions and rundown on your setup.

I picked up my Matrix Audio SI-1 today, and I too would agree with your finding it somewhat "dull" sounding, or certainly a bit contained overall fresh out of the box. As it were prior to the SI-1 entering my setup it sounded ever so slightly on the warmer side of things, whereas now (i.e.: early on with the SI-1) it appears to take on a slightly more neutral direction.  

What is already apparent however is a calmness and clarity to the sound and a distinct feeling of lack of smear and better sense if delineation throughout, also into the lower octaves, though it doesn't appear to be a the expense of the more holistic aspect; there's a simplicity even to the presentation that's beguiling. 

Oh, well - it's early days yet so what am I rambling on about? Looking forward to see how this develops once the SI-1 has more hours and days under the hood. 

lalitk's avatar
lalitk OP
6,179 posts
 

@phusis 

Congrats on SI-1..I would give it atleast 50 hours to settle down in your system. Looking forward to your final take. 

mammothguy54's avatar
mammothguy54
975 posts
 

@phusis @lalitk Yes indeed, phusis, let it run in for days with signal passing through.  Just 5 days ago I became ambivalent about it, again.  It seemed to have drifted back to being a bit on the dull side, particularly with plucks of guitar strings.  Then, yesterday I gave it a long listening session.  No analog, just digital source.  I have to say, it was the best my digital source has ever sounded.  All of the gentle and calmness, but the guitar was somewhat better, and vocals and all other instruments were just right.  

I am one to make small incremental "nudges" to the sonics of my system.  For instance, my phono stage has several loading settings, but it also has a custom loading slot for ones' choice of resistor (type of resistor and ohms).  Though the fixed option 100ohm sounds great on my Umami Red, I find that 82ohm metal foil resistor sounds better.  It's just a small nudge, but it's just right.  Same is true, of course, for speaker and subwoofer placement.  Just a small change of position can make a difference.  

So, I am now wondering.  Would the SS-1 Pro switch connected to my ethernet in the other room (where my router is) provide that nudge for things such as the pluck of a guitar string?  I welcome your thoughts.

audphile1's avatar
audphile1
7,888 posts
 

@phusis and @mammothguy54 looking at the build, I would run the SI-1 round the clock for a full 200hrs minimum passing signal thru it before you conclude what it sounds like. With network filters I usually like to do the evaluation with the filter in place for several days, then go back to direct connection and that usually tells the story. 
 


 

phusis's avatar
phusis
1,392 posts
 

@lalitk --

Thanks. It looks like the SI-1 needs a more lengthy run-in process than first anticipated to settle in sonically. More on that below. 

@mammothguy54 --

In terms of the SI-1 taking a turn for the worse in its development following its first some +50 hours of positive sonic progression, I can mirror that too. It didn’t make much of a difference after about 24 hours being turned on and with signal pass-through, but then just a few hours later approaching 30 hours it suddenly started to bloom and show its mettle more readily. This continued to some 65 hours (yesterday) after which it became leaner and more stifled again, only for the pendulum to swing in the opposite direction today with a slightly thick and congested imprinting. A rocky ride for sure. 

Actually this follows a more typical pattern of running in new component and cables in my setup with a positive development the first some 60-90 hours, then a turn for the worse in a rather fluctuating manner the next 75-100 hours after which things finally begin to settle in, so I’m not alarmed as is. Some prefer to be physically absent from this stage of running in components, but I’ve always liked to be "hands on" through the process - frustrating it may be. Right now I’m likely in the slump of things, so to speak, so I don’t expect the next few days to be a hoot.  

Great to learn though you appear to be on "the other side of things" and can now begin to appreciate the fuller qualities of the SI-1. How would you say the SI-1 has influenced the tonal balance compared to not using it? 

@audphile1 --

Indeed, 200 hours (or even more) seems to be a good mark for when to be able to assess the potential of the SI-1 more fully. Back to direct connection (in my case to a Delock filter) is an effective way to get a bearing on where one is headed with a new product, yes. So, as they say: to be continued. 

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