SMSL SU-9

The SMSL SU-9 is a balanced DAC that decodes MQA. It is based on the Sabre ESS9038 Pro chip, and you can get one for $399.

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Introduction

For the last couple of years, we’re observing the race for the budget audiophile’s wallet. More and more manufacturers are introducing new models promising an unmatched performance to price ratio. SMSL is one of the companies in pole-position, that are redefining the budget DAC and AMP market.

The hero of today’s review, the SU-9 is marketed as the next big thing. Fully balanced architecture, the ESS9038 Pro chip and MQA decoding. It also creates a stack with the SH-9 balanced THX amp, which we will review in the future.

Packaging

The SMSL keeps its packaging still. As always, you can find it inside a double box, with an AC cable, USB-B cable, and the remote and DAC itself. Everything is secured with a lot of foam inside, so you don’t have to worry about the stuff in the box when it finally arrives.
The whole process of unboxing is short and simple, to make you able to listen to the SMSL SU-9 as soon as possible after the courier leaves.

That’s the correct way of presenting such a product – we don’t have to pay for a fancy packaging, and as everyone knows – in this price range, some compromises have to be made. Luckily, it’s the least important part of the device.

Build quality

The SMSL SU-9 is very well-built, but it’s relatively light at 800g, considering it has a built-in AC adapter. It is made of three metal parts, the top, bottom, and the frame. These are pretty thick pieces of metal, so the whole device makes an excellent impression in-hand. The same goes to the screen placed on the front. It has perfect viewing angles and great colors thanks to the IPS technology. You can choose its brightness in the options, starting when it is almost turned off to a really bright setting.

The potentiometer that’s placed next to the screen has an excellent click, but it isn’t really stiff. It wobbles a little bit, but there’s no feeling that it would fall off. Overall, it’s rather accurate and it provides a satisfying feedback. All connectors at the rear part are rigid, but RCA connectors are tinier than usual – my cables have tight plugs, so that doesn’t bother me personally.

Overall, the SU-9 is well-made, minimalistic and modest looking. I prefer it by miles to this asymmetric design of M200 which is a nightmare to pair aesthetically with just about everything.

Functionality

The SMSL SU-9 provides a pretty nice list of functionalities, but some of them don’t make a real difference in my opinion.

Beginning with the inputs and the outputs, SU-9 has four options for digital input, which is a standard setup. There, you’ll find the USB, Coax, Optical, and Bluetooth, which supports the LDAC with an excellent usable range. Going forward, there’s an option for PCM Filters, which are built-in in the Sabre chip. They make a subtle difference but can help to set the SU-9 to your taste. My favorite filter is the “Fast hybrid”, which sounds the most natural among the rest, which are: Brickwall, apodizing, slow minimum, fast minimum, fast linear, and slow linear. The third option is the DSD Filter. You can choose between 47, 50, 60, or 70 kHz cut off, where the smaller one provides the most natural sound, and the last one will give you the most extended signal.

The next part is “Sound Colour.” To be honest, for me, this option could not exist. All the differences it provides are so small and almost invisible, the only option (compared to “Standard”) is the “Tube 3”, which gives a little warmer and darker sound.
The rest of the settings isn’t that important. In a few words, you can choose the volume (variable or fixed), DPPL bandwidth, brightness, restart the device, and check the present soft version.

Lastly, the previously mentioned Bluetooth supports the UAT codec. What is it?
It’s basically a revolutionary codec supporting 192kHz and up to 1.2Mbps bitrate. That basically means, that if you’re into some Bluetooth action – you’re in for a treat.

Sound

The SMSL SU-9 is one of the most competitive DACs at this price range. If you perceive SMSL products as the ones with a digital kind of sound, the SU-9 would totally change your perception. It offers a midrange focused sound, with a nice slam of the bass and outstanding microdynamics. However, it still remains transparent and provides many emotions in the sound, which reminds me of acoustic concerts that I loved before the pandemic.

The bass is delicately warmed and unbelievably exact. It isn’t as speedy as the lightning but also doesn’t get slow. It remains genuinely natural, with a pleasant slam that can’t be understood as dry or lifeless, but it stays far away from being lazy and muddy. During my listening sessions, it never gets lost, it’s always spot-on. Every music band’s kick drum sounds natural, like live music, even tracks made by garage bands that often don’t care about each instrument’s proper tuning. 

Thanks to the massive soundstage of SU-9, the bass can swirl encompassing and play from all around without being an obstacle for midrange or the treble. That creates a fantastic sense of the sound floating around you, almost as it was suspended in the air. And yes, I’m still talking about the bass. Show me a 400$ DAC that can do this.

The SMSL SU-9 is well-known for its midrange. And well, I must admit it is right. All vocals are juicy, with a little addition of smoothness. They are always the principal part of the performance, entirely separated from all other sound sources. It doesn’t matter if you listen mainly to pop, alternative, rock, rap, or jazz. The midrange always makes you listen more and more. I’m not a fan of rock music, but those vocals and guitars make me want to click play on “The Neighborhood” discography. It is another level of pleasure. 

Higher mids are also gorgeous. As I mentioned a few reviews before, my favorite album for this part and the treble is “Lush” by “Snail Mail”, and it doesn’t fail me this time. Using the Topping MX3 as an amplifier and the AKG K702, it is delicately too sharp (it’s better with Sound Color set at Tube 3), but one quick switch for Fyne F500, and it goes back to that beautiful, delicate manner that let me fall in love with it. 

The treble makes a feeling like it is the less important part than the others. Don’t get me wrong, it is very correct, but it doesn’t try to give something more. It has an excellent detail reproduction and extension, but sometimes I miss some sparkliness and just more life in that part. It’s not sharpened nor brightened, but also doesn’t get blurry and too delicate. Don’t make it fool you though, as coming back to the JDSLabs Atom Dac shows a more prominent, but at the same time, less detailed and sophisticated treble response.

All drum plates are splashy, and I’m simply able to hear how they bounce off, but they don’t try to get at the front and become the central part. On the other hand, the piano has a different timbre. It isn’t totally neutral and correct. The SU-9 provides some delicate slowing down at the end of each tone. That makes it a little more intimate for me. That kind of sound may be easy to disregard at first, but it grabs you by your ears and pull more and more every single time.

The soundstage feels like the whole universe. It doesn’t end. You can hear everything from every direction, without a mess at the back as it usually is. It is very precise, with a lot of air and outstanding imaging. That’s easy to hear in every music genre, but I love that, especially with Chopin’s realizations and other symphonic music. It is like swapping the listeners and the musicians’ positions, the music isn’t at the stage, but all around. And that’s good, particularly when the main subject is moved slightly to the front of the head.

If you know Dead Can Dance (and you should know them), you’ve heard how big soundstage they create in their music. All of that is here, with every strange sound in the background. The SU-9 can cause the creeps on the back with headphones that have a great soundstage (even cheap IEMs like Moondrop SSP), making the listener feel like he’s inside of something bigger than just headphones.

When paired with the Unique Melody MEST (review coming soon), the soundstage is simply put spectacular. It stretches far and wide, and the imaging is just superbly true-to-life. It’s great to see a device in this price range creating such an excellent soundstage, which completes the rest of the sound, creating a magnificent 399$ DAC.

Summary

I think that SMSL did an excellent job with their new SU-9. It’s a very natural and pleasant sounding DAC loaded with functions. On top of that, it is built to last, has a great choice of inputs/outputs, and won’t hurt your wallet too much. What’s not to like?

I have the confidence to call the SMSL SU-9 “the best DAC in this price range”.
Definitely recommended.

Disclaimer: SMSL SU-9 was sent to us in exchange for an honest review by Apos Audio – Thank you!
This review is my unbiased opinion, and it wasn’t influenced by anybody.

You can get the SMSL SU-9 here.

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Gear used during this review for the sake of comparison and as an accompanying equipment:

• Headphones – Philips Fidelio X2HR, Audeze LCD-3, Bqeyz Spring 2, Craft Ears Four, Hifiman HE400i 2020, AKG K702, Campfire Audio Vega
• Sources– Topping DX7 Pro, SMSL M300+SP200, Chord Mojo, iFi iDSD Neo, Topping DX3 Pro, EarMen TR-Amp, iDSD Signature, Topping D50s, xDuoo XD-05 Plus