Matrix Audio SU-1 USB Isolation Switcher Review: The USB Upgrade You Didn't Know You Needed
Read Time: Approx. 7 min.
TL;DR:
- The SU-1 sits between your USB source and your DAC, combining galvanic isolation, linear power and source switching in one chassis.
- A professional-grade isolation chip separates the data, power and ground lines to break ground loops and block high-frequency noise from computers and other sources.
- A fully potted toroidal linear power supply replaces noisy USB bus power and adds overcurrent and short-circuit protection.
- Three inputs (2x USB-B, 1x USB-C) and two outputs (USB-A) are switched with a single front-panel button.
- Supports cable runs of up to 4 meters per side (8 meters total), so your source and DAC don’t need to share a shelf.
Targeting The Weak Link Hiding Between Your Source and DAC
From the placement of sensitive hi-fi components to the audio cables you use to connect them, every link in your signal chain matters. At Moon Audio, we constantly talk about how important it is to identify and address the weakest link in your system. Most people assume we're only referring to audio cables, but there's an even sneakier "weak link" hiding in the digital audio system that you've probably never thought of, and it's been sitting right between your source device and DAC the entire time.
All digital audio components generate some level of electrical noise, but because that noise isn't necessarily audible, we tend to dismiss its impact on our system. Matrix Audio has spent the last few years building out one of the most thoughtful lineups of network audio products to address this very problem. The Matrix Audio SU-1 USB Isolation Switcher is the company's second Isolation product that combines source switching, electrical isolation, and linear regulated power in one unit.
Where the Matrix Audio SI-1 Audio Grade Network Isolator sits between your router and Ethernet-connected audio device, the SU-1 sits between a USB source and a USB DAC or digital interface. We're diving into the problem the SU-1 solves, how it works, and where it fits in your system.
PROS
- 3 functions in one box: isolation, clean power, and switching
- Simple, one-button control with LEDs that show the active input and output
- Built to withstand long cable runs so you can place your source device and DAC far apart if needed
CONS
- Single-button cycling with no remote forces you to click through inputs to reach the one you want
The Problem the SU-1 Solves
If you stream music from a digital source to your DAC, your signal chain can pick up ground loops, high-frequency interference and general electrical noise. It doesn't matter whether that source is a computer, a tablet, or a smartphone. If it connects to your DAC over USB, this applies to you.
Most of us with a digital music collection keep it stored and backed up on a computer. It's the natural home for a carefully curated library, so using it as a source makes sense. The catch is that computers are noisy. They run multiple programs at once, and their fans, switching power supplies, and tiny circuitry all add to the chaos. USB carries more than digital data. It also carries power and a shared ground, so some of that noise can travel down the cable straight into your DAC. The result can be a raised noise floor, an audible hum from a ground loop, or a background that just isn't as black as it should be.
Many of us also have more than one digital source and sometimes more than one DAC too. That usually means reaching behind a rack to swap cables every time you want to change sources. The SU-1 tackles both problems with 3-input and 2-output switching for multi-device shared operation.
How the SU-1 Works
Matrix Audio calls the SU-1 a "3-in-1" device, combining electrical isolation, multi-source switching, and linear power in one chassis.
Isolation
Think of the SU-1's electrical isolation as a traffic guard. It uses a dedicated professional-grade digital isolation chip to electrically separate each signal path and isolate grounds. USB data gets the "go" arrow, passing through safely, while electrical noise gets the "stop." The isolation chip physically breaks the electrical connection between data, power, and ground lines at both ends. This breaks ground loops, blocks high-frequency interference from the source, and also helps protect downstream gear from power surges.
It provides lower system noise, quieter and more open sound, and the full potential of your audio system. The sonic results are subtle, but those small changes add up when you're chasing sonic perfection.
Multi-Source Seamless Switching
Beyond isolation, the SU-1 acts as a signal hub for switching multiple USB audio devices. Three selectable inputs (2x USB-B, 1x USB-C) and two isolated outputs (USB-A) let you connect up to three digital sources and route them to two separate USB DACs or audio interfaces.
It would be counterintuitive if the SU-1 featured a complicated front panel with buttons for each input and output, so a single button on the front panel handles the switching. Short-press to cycle through USB Type-C1, Type-B1, and Type-B2 inputs. Long-press to switch between USB Type-A1 and Type-A2 outputs. A status LED lights up, showing the current input and output chain.
Clean, Precise Power
To support the SU-1's primary functions, Matrix Audio incorporates a fully encapsulated toroidal transformer linear power supply, paired with multiple ultra-low-noise regulators. It delivers a steady 5V/1000mA ultra-low-noise output with built-in real-time detection that automatically detects overcurrent and short-circuit faults and cuts output quickly to protect downstream audio gear.
Matrix Audio truly thought of everything when engineering the SU-1. Features and functionality beyond the core three are included intentionally to support your system, not hinder it. Anybody who's run audio cables for their own system is familiar with the delicate dance of maintaining signal integrity over distances. Matrix Audio optimized the USB transmission impedance on the SU-1 to support cable runs of up to 4 meters on each side, or 8 meters in total, without data loss. That means sources and DACs don't need to sit next to each other, leaving you with more room to plan and adjust your system when needed.
All of these functions sit inside a CNC-machined aluminum chassis that's shielded against outside RF and EMI. The SU-1 is a small unit measuring approximately 4.7" wide, 8.1" deep, and 1.7" tall, and weighs 3.84 pounds.
Features
- 3-in-1 design that combines source switching, electrical isolation, and linear regulated power in one unit
- Keep up to three USB sources and two DACs or digital interfaces connected, with no swapping cables between devices
- Professional-grade digital isolation chip separates the data, power, and ground lines to remove ground loop noise and high-frequency interference
- Surge and lightning protection helps safeguard valuable downstream audio gear
- Fully encapsulated toroidal transformer with multiple ultra-low-noise regulators gives connected USB devices clean, stable power
- Real-time load detection quickly cuts output on overcurrent or short circuit
- One-button control: a short press cycles the inputs and a long press switches the outputs
- Front-panel status LEDs show the active input and output at a glance
- Optimized USB transmission impedance supports long cable runs without signal loss or packet loss, so sources and DACs can sit farther apart
Where It Fits in Your System
Unlike the SI-1 that sits between your router and music streamer, the SU-1 sits between your digital source and your DAC. Your computer, streamer, or network transport plugs into one of its inputs, and the SU-1's output feeds your DAC.
The SU-1 makes sense for listeners who:
- Use a computer as their main source and want to keep noise out of the DAC
- Hear a hum or buzz that indicates a possible ground loop
- Own several USB sources (say a desktop computer, a network transport, and a tablet) and are tired of swapping cables
- Run two DACs and want to easily switch between them
- Need the flexibility to place their source and DAC away from each other
Dragon Cables
When you're putting this much effort into your system, you can't swap one weak link and not address the other. Upgrading to one of our Dragon Audio Cables, like the Black Dragon USB Cable, will ensure your digital audio data is transported without a single hiccup. Built with high-quality materials, shielded to ward off outside interference, and designed specifically for USB data transmission, our Dragon USB Cables reduce stock USB cable issues such as packet loss and jitter.
Our HiFi Audio Dragon Cables bring out more of what you love in your music and audio gear. If you love your headphones but wish they had a bit more top-end sparkle - a Silver Dragon Headphone Cable would be a great option. If your USB cables keep dying - as many stock cables do - then check out our quality USB Audio Cables. We say time and time again that materials matter, and our audio cables and custom geometries actually help to bring out those desired properties in your gear and music. We make tons of custom options for our customers so that you can get the right HiFi Audio cable for your exact needs. If you have any questions feel free to Contact Us and we'll be more than happy to help.
Generally, stock audio cables are manufactured with subpar materials, metals with impurities, poor geometries, and an overabundance of layers to make them look and feel like a fire hose. Inconsistency and lack of quality control in stock cables can lead to poor sound quality and a veiled sound vs. what the musician intended for you to hear and feel from the music. Dragon Audio Cables are handcrafted with the highest standards and made to order according to your specific needs. At Moon Audio, we create a custom cable for you using the highest quality UP-OCC silver or copper conductors that can be manufactured. UP-OCC metals are void of impurities and are optimized for signal transfer and sound quality. We have one of the largest collections of audio and headphone connection options available online and we create limitless audio cable options depending on your specific gear and needs.
Why Dragon Cables?
You’ve heard the saying that a chain is only as strong as its weakest link, right? Well, the same applies to your brand new audiophile-grade headphone or other audio components. The weakest link, in this case, is your stock audio cable or the cheap interconnects the manufacturer threw in the box just to get you up and running. Why is the audio cable always an afterthought, when it’s just as important as the rest of your system? At Moon Audio, we use the purest and best raw materials in our cables to unveil your music. We believe that materials matter and your audio cables should have the same care and craftsmanship that manufacturers put into their audio components and headphones. Audio cables are ultimately the connection to your music. The fact remains that cabling is often considered the last priority to that of the main product and a means to cut down the overall production costs. It’s as simple as that. Dragon Cables elevate every note - as if you were hearing your favorite music for the very first time.
Verdict
For the audiophile trying to squeeze every last percentage of performance out of their audio system, a component like the Matrix Audio SU-1 USB Isolation Switcher makes sense. It's a three-in-one unit that will get you there without adding three extra components to your rack. The SU-1 isolates your DAC from the noise your source device puts on the USB line, it replaces dirty bus power with a clean linear power supply, and it lets you switch between up to three sources and two DACs with the click of a single button.
The sonic improvements are subtle rather than night-and-day, but if you currently listen through a computer, or you've been living with a hum you can't track down, the SU-1 will show you just how revealing the rest of your system is. The SU-1 targets the weakest link that most listeners never think about, and the convenience of never having to reach behind your rack again to swap USB cables is a major plus.
When you're putting this much effort into your system, you can't swap one weak link and not address the other. Upgrading to one of our Dragon Audio Cables, like the Black Dragon USB Cable, will ensure your digital audio data is transported without a single hiccup. Built with high-quality materials, shielded to ward off outside interference, and designed specifically for USB data transmission, our Dragon USB Cables reduce stock USB cable issues such as packet loss and jitter.
If you stream over a network rather than USB, the SU-1 has a sibling, the Matrix Audio SI-1 Audio Grade Network Isolator, that tackles the same job, but on the Ethernet side.
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What's in the Box
- Matrix Audio SU-1 Isolated USB Switcher
- 1x Power Cable
- User Manual
- Warranty Card
Specifications
Weight: 1.58 kg (3.84 lbs)
Width: 120 mm (4.72 in)
Depth: 205 mm (8.07 in)
Height: 44 mm (1.73 in)
USB Type B Inputs: 2x 480 Mbps High-Speed USB Type B | Input Power Requirement: <5V 100mA
USB Type C Input: 1x 480 Mbps High-Speed USB Type C | Input Power Requirement: <5V 1000mA
USB Type A Outputs: 2x 480 Mbps High-Speed USB Type A | Maximum Output Power Rating: 5V 100mA
Input LED Indicators: 3
Output LED Indicators: 2
Power Voltage: AC 100V-120V 50/60Hz or AC 220V-240V 50/60Hz (factory-fixed)
Power Consumption: <15W
