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

Sidebar conversation related to the isolation of this type. A year ago I bought an LHY EFI which is highly similar to the SI-1 for my 2 ch system downstairs.. This April I replaced it with an LHY SW10Pro switch and it was no longer needed. (Yes the LHY Switch is really nice) We also switched from our Spectrum Cable boxes to the Xumo Stream Box so I placed the LHY EFI just before the Xumo with a very nice DH Labs Reunion cable connecting them. Well it helped! Visually I am not sure of any big changes but the audio from our modest HT setup  is now so much clearer, we have set the volume on our Yamaha HT AV receiver far lower and everything sounds better. SO, these things may help in that arena too if you care to try it out. 

@fthompson251 Thank you very much for your comments and information.  I looked into the SW10Pro just now and it is one excellent unit.  I just made the investment into the Si-1 and will live with it.  At some point I will examine potential changes in this arena, as time passes and technology may change a bit.  It seems the SW10Pro is at the leading edge of that technology.  But I did just make the first leap.  The analog rabbit hole I have been living with for so many years found a partner...the digital rabbit hole.  Darn it!!!

The analog rabbit hole I have been living with for so many years found a partner...the digital rabbit hole.
 

hahaha. Digital rabbit hole is way deeper. Don’t go crazy compounding on filters with switches, etc. less is more sometimes 

LAN filters and Optical Breaks are different methods of addressing a common issue with digital.  DC noise.  Optical breaks are 100 % effective but because they are active they generate their own noise that they put back but of course it is a net improvement. 

When an Ethernet cable is run from the clean side of the optical break to a streamer in the noisy environment of other audio gear and cables it will pick up EMI/RFI.  There is still a case to use an Ethernet filter on the output to further protect the streamer from an infusion of noise.

Using an ethernet filter on the input of the optical break can also have benefits as the break is receiving a cleaner signal.  The first optical converter will be working in a quieter environment and can produce a cleaner optical signal.

I don't see it as a one or the other approach.

@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.