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

Has anyone compared this Si-1 and the similar functioning iFi Lan iPurifier Pro?

 

“I am just loving the sound of my digital front end.”
@grannyring 

Congrats on your purchase! 

In a system as refined as yours, I would expect a more three-dimensional presentation, along with greater ease, flow, and overall naturalness in the music. Having lived with the SI-1 for some time now, I’ve found my digital streaming playback to be noticeably more engaging and enjoyable. On familiar recordings I know well, I’m hearing very meaningful improvements in several areas,

  • The air around the piano
  • The decay of cymbals
  • The body and texture of double bass
  • Vocal phrasing and breath
  • A stronger sense of musicians occupying a real acoustic space

When you’re already working from such a high-performance digital front end, the SI-1 isn’t about transforming the sound. Rather, it’s about extracting those last few percent of performance by reducing network-borne electrical noise before it reaches the streaming player. In my experience, that’s where the SI-1 truly excels, distinguishing itself from the various network filters and switches we’ve tried over the years.

Cheers! 

@lalitk 

Rather, it’s about extracting those last few percent of performance by reducing network-borne electrical noise before it reaches the streaming player. 

Garbage in, garbage out, as they say.

Let's all strive to have a garbage-free musical environment. laugh

@lalitk Thanks for posting this review, I have great confidence in your ears. I am currently using an Uptone Ether Regen with optical in, and ethernet out to my Antipodes server and Bricasti DAC. Because of this configuration I need a bit more than the SI-1 offers, but this thread got me looking at their SS-1 switch. Previously I was leaning heavily towards an LHY AS-6, but the Matrix SS-1 is intriguing. Has anyone had experience with this switch?