·Basic Information

·Author: Huang Peng

Huang Peng is highly influential in the Hi-Fi and professional audio field in China. He combines multiple identities as a senior audiophile, expert, and acoustic designer. He is recognized as a "golden ear" in the audiophile circle. He is not only a developer and strict reviewer of audio products but also a designer of the perfect listening environment. Just as its slogan "Audio is my work, music is my life, hoping to resonate with you" expresses, it does not chase mass traffic but is committed to serving the player community that aims for the highest sound quality. Through rigorous reviews, professional acoustic knowledge, and genuine musical passion, it has become a key platform with important reference value and community influence in this field.

Does a dCS DAC Sound Better with Streaming via Ethernet or USB?

Impressions from Trying the Matrix Audio SU-1

It's been over two weeks since I unboxed the Matrix Audio SU-1 isolator. Let me throw in a few more photos:

Over the Mid-Autumn Festival and National Day holidays, the SU-1 got borrowed by a friend who's deep into digital streaming. I didn't get to spend as much time with it as I'd hoped, but my friend was even more excited than I was — probably because he's also a user of the Matrix Audio SI-1 network isolator that I recommended earlier. When he saw me unboxing the SU-1, his curiosity went through the roof.

The SU-1 and SI-1 share the same design language. Placed side by side on top of the Matrix Audio SS-1 Pro switch, the two little boxes look perfectly at home:

For me, the SU-1 solves a lot of those "I want it all" needs.

First off, it's a USB switcher — three inputs, two outputs — handling multi-source switching while reducing the risk of hot-plugging damage to your gear. On top of that, it offers galvanic isolation, tackling that dreaded ground loop noise problem — something many folks using active speakers with a DAC will recognize. And of course, it also does what we call USB "reclocking" or "cleaning": replacing the noisy USB bus power with a proper linear power supply, and reconditioning the incoming USB signal through a better circuit design before sending it out to the output.

In my own setup, I have two computers that need USB connectivity: a Windows machine running Jriver for local files, and a Mac Mini serving as my Roon Core. But my dCS DAC only has a single USB input. Before the SU-1, that USB port was permanently occupied by the Windows machine. Whenever I wanted to play Apple Music through the Mac Mini, I had to route the USB signal through a Yulong DP-1 to convert it to AES and feed it into the dCS that way. Now with the SU-1, the dual-host switching problem is truly solved. If you're curious about my approach, check out my previous article — 2024 Year-End Roundup: Digital Edition (The Ultimate Apple Music Solution).

With the SU-1, I can now use a single Mac Mini as both Roon Core and playback endpoint.

For a more detailed breakdown of the SU-1, I'll leave that to the official product page. Instead, let me put together a quick comparison table to show how the SU-1 stacks up against similar products on the market:

This is taken from the official exploded view — I'll save myself the trouble of tearing it apart:

As you can see, the SU-1 physically isolates the input module (left) from the output module (right). The power supply also uses separate windings to feed the input and output independently. Those two gold Hi-Fi capacitors really stand out. In the red circle below, the larger QFP-packaged IC is the USB high-speed digital isolator chip, and the smaller ICs beneath it are companion signal buffer/power isolation helper chips — this is the core isolation path of the SU-1:

Alright, enough rambling — let's get to the main event. While I was away on holiday, the SU-1 received extremely high praise from one of my friends. Let's call him "Couhe Jiaozhu"(roughly ‘Master of Good Enough’). Couhe Jiaozhu and Brother Seaside Fisherman are both owners of the dCS Rossini CD player. Brother Seaside Fisherman is a hardcore Roon streaming enthusiast — you can check out his article My Computer Audiophile Journey 2013–2024 — clearly the type who loves to tinker. The SI-1 network isolator made a huge difference in his system, and he even left a lengthy comment in the comments section of that article. Feel free to go back and read More boxes, more problems? Real-World Impressions of the Matrix Audio SI-1 Network Isolator. As for Couhe Jiaozhu, he's a seasoned Hi-Fi guru whose favorite phrase is "good enough is good enough." But once he finds something he can't bear to unplug, he buys it immediately — and selflessly recommends it to everyone around him. Hence the nickname. The SU-1 isolator made a very noticeable difference in his system. Before I even got home, he'd already placed his order:

When I first fired up the SU-1 at my place, my initial impression was that the sound became cleaner and more refined after adding the isolation — especially in the treble region. Brother Seaside Fisherman reported the same thing at his place. As for what changes Couhe Jiaozhu heard, I had to go experience it myself. So I rushed back during the last two days of the holiday to pay him a visit.

Brother Seaside Fisherman and I both use Ethernet streaming via Roon into our dCS DACs. Couhe Jiaozhu, on the other hand, doesn't use Roon. He runs Audirvana Studio on a Mac Mini to play local files stored on a NAS, and streams Apple Music via iPad — both fed into the dCS through its USB input. So the SU-1 perfectly solved his dual-source switching needs. Here's a shot of Couhe Jiaozhu's gear: turntable is a Panasonic SP10MKII, phono stage is a Mark Levinson 7A, digital source is the dCS Rossini, preamp is a SPECTRAL 30, power amps include an MC² 1250 and an ARC, and speakers are JBL 9800SE:

After several rounds of comparing Mac direct to dCS versus going through the SU-1, the effect was remarkably obvious — far more dramatic than what I heard in my own system. Direct connection gave a flat soundstage with decent tonal balance. After adding the SU-1, the three-dimensional soundstage opened up — it felt like someone had turned up the volume. Full-range detail was noticeably richer. Truly fascinating. At this point, I couldn't help wondering: why such a big difference across different systems? Is dCS simply better suited to USB?

The four of us discussed this and came up with a theory: Brother Seaside Fisherman and I had both done a series of network optimizations, so the gap between Ethernet streaming to the dCS and using USB was narrower. In Couhe Jiaozhu's system, which had virtually no network optimization, adding the SU-1 to the USB path brought a dramatic improvement. We all described it as feeling like the volume had been turned up a notch — more detail, more Hi-Fi, a more dimensional soundstage!

Now for the bonus round. Speaking of USB cables, lots of people have been asking me which ones to go for. I'll be honest — I haven't tried that many Hi-Fi USB cables, but I firmly believe in the importance of cables. The two most frequently asked about are the AudioQuest Diamond and the WireWorld Platinum Starlight 8. Coincidentally, we had both on hand:

So we did a quick comparison. Going direct from Mac to dCS, the WireWorld sounded delicate, warm, and well-balanced across the frequencies, with fine detail retrieval. The AudioQuest Diamond, on the other hand, had a stronger three-dimensional presence, with notably better bass punch and elasticity — classic AudioQuest flagship digital cable character.

When we inserted the SU-1, the differences between the two cables became much smaller. Both presented a well-defined three-dimensional soundstage. However, the cable choice seemed to matter more on the input side of the SU-1 than on the output side. Our guess is that the SU-1's robust power supply performance narrows the gap at the output end.

So, back to the original question: for streaming with a dCS DAC, is Ethernet or USB the better route? Our conclusion: if you want to minimize network tweaking, USB with an isolator is the easiest path to great sound. If you prefer online streaming, invest your efforts in optimizing your network environment and Core host. Either way — have fun and enjoy the music!