Matrix Audio SI-1 Audio Grade Network Isolator

The Matrix Audio SI-1 is an audio-grade network isolator that uses active optical-electrical isolation to eliminate electromagnetic interference, ground loops, and network noise before they reach your streamer or DAC. Dual-channel optical transmission with independent send and receive paths, two femtosecond clocks, and an audio-grade linear power supply ensure data integrity and timing precision across a full gigabit Ethernet connection. For streaming systems where clean signal matters, the SI-1 addresses the problem at the source: the network cable itself.

Key Features of the Matrix Audio SI-1 Network Isolator

• Active Optical-Electrical Isolation: Converts electrical Ethernet signal to optical, then back to electrical on the output side, creating a complete break in electrical continuity between your network equipment and audio components.
• Dual-Channel Optical Transmission: Independent send and receive paths eliminate mutual interference and prevent signal crosstalk at the source.
• Dual Femtosecond Clocks: Two precision clocks reduce jitter and timing errors for accurate data delivery to your streamer or DAC.
• Audio-Grade Linear Power Supply: Dual-winding potted toroidal transformer with multiple LDO (Low Dropout) regulators provides stable, clean power without the noise of a switching supply.
• CNC Unibody Aluminum Enclosure: Machined from a single block of aluminum for maximum shielding against external interference and a solid, resonance-free chassis.
• Full Gigabit Throughput: Supports 10/100/1000Mbps auto-negotiation. More than enough bandwidth for any streaming format, including high-resolution DSD and MQA.
• Lightning, Surge, and ESD Protection: Protects connected audio equipment from voltage spikes traveling through the Ethernet line.
• Switchable Rear Ethernet LEDs: Rear port LEDs can be turned off to eliminate light pollution during listening sessions.

How the Matrix Audio SI-1 Optical Isolation Works

Most network equipment (routers, switches, even NAS drives) introduces electromagnetic interference and ground-level noise onto the Ethernet cable. When that cable connects directly to a network streamer or DAC, that noise can affect the analog output stage. The SI-1 solves this by converting the electrical Ethernet signal into an optical signal using fiber optics inside the unit, then converting it back to electrical on an isolated output port. This creates a complete galvanic break: no electrical continuity, no shared ground plane, no conducted noise. The output port even incorporates a physical electrical isolation washer to reinforce the separation between input and output sections.

Precision Clock Architecture

Digital audio streaming relies on precise data timing. Even small timing errors (jitter) during transmission can affect how a DAC reconstructs the analog signal. The SI-1 uses two femtosecond-class clocks to reclock the data stream after optical conversion, reducing transmission errors and improving timing accuracy. Combined with the dual-channel architecture that keeps send and receive paths independent, the result is a cleaner, more stable data stream arriving at your audio component.

Audio-Grade Power Supply Design

The SI-1's internal power supply is built around a dual-winding potted toroidal transformer, the same topology found in high-end audio amplifiers and DACs. Multiple LDO (Low Dropout) voltage regulators provide clean, stable power to the optical isolation circuits and clocking system. This is a deliberate choice: switching power supplies (common in consumer networking gear) generate high-frequency noise that can couple into sensitive audio circuits. The linear supply eliminates that noise source entirely. Total power consumption is under 15 watts.

Network Compatibility and Connectivity

The SI-1 has one RJ45 input and one optically isolated RJ45 output, both supporting Gigabit Ethernet (IEEE 802.3, 802.3u, 802.3z, 802.3ab standards). It works with any Ethernet-connected audio device, including streamers, network DACs, music servers, and NAS units from any manufacturer. Place it inline on the Ethernet cable directly before your audio component, or between your router and a dedicated audio network switch. The 2K MAC address table handles any home network configuration.

CNC Aluminum Construction

The enclosure is machined from a single block of aluminum using CNC milling, creating a seamless, resonance-free chassis that doubles as electromagnetic shielding. The ventilation pattern on the side panels allows passive cooling without any moving parts. Front panel LED indicators show power status and link activity at a glance. At 120mm wide, 205mm deep, and 44mm tall, the SI-1 is compact enough to sit behind or alongside your streamer without taking up significant rack space. It weighs 1.54 kg (3.4 lbs).

Explore the Matrix Audio Network Accessories

The SI-1 is designed to work alongside the rest of the Matrix Audio network product line. For systems with multiple Ethernet-connected components, the Matrix Audio SS-1 Audio Grade Network Switch adds eight Gigabit ports with femtosecond clocking and an SFP optical isolation port. The Matrix Audio SS-1 PRO goes further with a built-in linear power supply. Place the SI-1 upstream of either switch for maximum isolation, or use it standalone directly before a single streamer or DAC.

The Listening Room Difference

We're a third-generation family business with a brick-and-mortar showroom in Chestertown, Maryland, and a reputation built on trust, not hype. Whether you're visiting in person or ordering online, we bring decades of experience, personalized service, and honest guidance to every interaction. We don't just ship boxes. We help build systems, answer your questions like real humans, and make sure every detail of your setup is right, from the cables to the final connection. Our passion is helping you get the most out of your gear, with support that lasts well beyond the sale.

Matrix Audio SI-1 Specifications