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

@soix 

I wasn’t expecting much difference either, but that wasn’t the case in my system. This wasn’t a five-minute hot take…I spent a solid hour running the same playlist through both. The SI-1 consistently dug deeper, revealing more layers and low-level detail. 

As they say, progress doesn’t stand still and in this case, it’s clearly moved the needle in a meaningful way.

@audphile1 

If you’re not using any filters upstream, then I believe adding SI-1 or something similar in your signal chain should net good results. 

@lalitk 

Yep, no filters. Just eero straight to network card. I had a trendnet switch in between but It didn’t do anything vs the straight connection so I pulled it. 
It will be interesting to see what this filter can do.
 

A few years ago I definitely had noise in my internet so I bought a couple of these TP-Link Gigabit SFP to RJ45 Fiber Media Converter | Fiber to Ethernet Converter https://a.co/d/0hqx2u6J and the double optical cable to connect the two. When I plugged in everything, Immediately I noticed a difference. After a year and a half of bitchin’ At the cable company, they replaced about a quarter mile of cable.  Sadly it was over the space of seven months!  In the spring of 2025, they ran fiber behind all the houses, so the only copper I now have is from the main line, to another pole between me and one neighbor and to my home. Maybe 200’.  A few months ago I moved my router closer to my streamer and I did not reinstall the fiber to Ethernet converters and I could not hear a difference. I guess getting all the fiber sure helped clean things up for me.

Nice write up. For the price of $699 US / $949 CDN (before shipping) that seems like a no-brainer, considering many are spending several times that on high end switches. 

 

@lalitk Thank you very much for your review of the Matrix Audio Si-1.  I have been eyeballing that device for about a month now, reading the posted reviews and especially enjoying the review from Hans.  I believe in simple solutions and the Si-1 delivers on that.  My system is highly resolving but I do realize that presently using just the Stack Audio SmoothLan in my ethernet connectivity is limiting the potential of my digital front end.  My intent has been to use the SmoothLan while researching and waiting for the right product to suit my needs.  Your review of the Si-1 helped me conclude to pull the trigger on the purchase and I'll be doing that either later today or tomorrow.

Thanks again.