The SMSL SU-2 is one of those DACs that feels a bit different from the usual budget crowd. It comes in at around $100 — $99.99 officially — which already puts it in a very competitive spot, but the way it’s put together isn’t quite what you’d expect at this level.

At a glance, it looks like a simple, no-frills desktop DAC, but once you start digging into the inputs and overall design, it’s clear SMSL had a pretty specific use case in mind. No USB, balanced outputs, AES thrown into the mix… it’s not trying to be a do-it-all box. Whether that works in its favour or not really depends on how you’re planning to use it.

Disclaimer: This sample was provided by SMSL for an honest review. All observations and opinions here are my own, based on my experience with the product.

SMSL SU-2

Features

The SU-2 looks fairly simple on paper, but there’s enough going on here to make it worth a closer look.

It uses the ESS ES9039Q2M DAC chip, along with a balanced analogue stage built around OPA1612 op-amps. You’ve got both XLR and RCA outputs on the back, which is good to see at this price, and it makes it easy to drop into either a balanced or single-ended setup without having to think too much about it.

Inputs are where things get a bit more particular. You’ve got AES/EBU, coaxial, and optical — but no USB input at all. That’s obviously going to catch some people off guard. In the right setup, it makes perfect sense, especially if you’re already using a DDC or some kind of dedicated digital source. But if you’re coming straight from a laptop or something similar, it does mean an extra step.

Other than that, it’s pretty stripped back. Fixed output, no volume control, no preamp features. It’s just a DAC, and that’s clearly the intention here.

Design

Design-wise, it’s very much in line with what SMSL has been doing for a while now. The chassis is compact and all metal, with a decent bit of weight to it for the size. It doesn’t feel cheap or hollow, and the finish is clean enough without really drawing attention to itself. It’s the kind of unit you set on your desk and forget about.

The front panel is about as minimal as it gets. No screen, just a row of small LEDs and a single button. The LEDs handle input and signal status, but it’s not something you instantly understand at a glance. You sort of get used to it after a while.

That one button handles power and input switching, which works, but it’s not exactly flexible. There’s no remote or anything like that, so once it’s set up, you’re probably not going to interact with it much anyway.

Around the back, it’s all pretty straightforward — digital inputs on one side, analogue outputs on the other. You also get a proper IEC power inlet, which is always a plus compared to USB-powered designs at this level.

Overall, it feels more like a small, purpose-built component than something designed to impress on first look. A bit plain, maybe, but it fits what the SU-2 is trying to do.

Setup

I’ll be honest, getting the SU-2 up and running wasn’t exactly straightforward. Without a USB input, it immediately forces you into using coaxial or optical, and that’s where things got a bit awkward. My CD player has a 3.5mm hybrid output, which meant figuring out the correct cable, and of course, the one I had on hand wasn’t the right type. It’s one of those situations where you realise pretty quickly that this DAC isn’t designed for convenience.

In the end, it was the iBasso DX260 MK2 that saved the day. Using its coaxial S/PDIF output with the included cable, everything finally fell into place. No adapters, no guessing, just a proper digital connection straight into the SMSL SU-2.

From there, I ran the SU-2 via its balanced XLR outputs into the balanced input of the Burson Soloist GT4. That fully balanced chain seems to bring out the best in the SU-2.

Once everything was set up properly, the initial frustration didn’t last long. The SU-2 settles in nicely. There’s a stable, composed feel to the sound, with clean imaging and a clear but natural presentation. It’s not pushing detail or sharpening edges for the sake of it, but resolution is there when you listen for it, and it comes through without effort.

This is the kind of setup with a synergy that grabs you straight away. The longer you listen, the more you notice how well it holds things together. In a proper setup, it just does its job properly—no tricks, no spotlighting, just a solid, confident performance.

Sound

The SU-2 doesn’t come across as a DAC that’s trying to shape the sound in any obvious way. If anything, it leans towards a clean, controlled presentation, but without tipping over into anything clinical or thin.

There’s a sense of stability to the way it handles a signal. Imaging locks in nicely, and instruments sit where you expect them to without drifting or blurring together. It’s not doing anything dramatic with stage size, but it doesn’t feel closed in either. More just… well organised.

Tonally, it stays fairly neutral, though you can pick up on some small tendencies if you listen for them. Low-end comes through tight and defined rather than full or weighty, which works well in keeping things from sounding bloated. The midrange has a natural, unforced quality to it — vocals in particular don’t feel pushed forward or held back, just placed where they should be.

Treble is handled in a similar way. It’s clean and reasonably extended, but not something that jumps out at you. There’s no obvious glare or edge, and it avoids that slightly artificial sharpness some ESS implementations can fall into. If anything, it plays things a bit safe here, but it suits the overall presentation.

What stands out more over time is how composed everything feels. It doesn’t try to impress in the first few minutes, and it’s not the kind of DAC that immediately grabs your attention. But the longer you listen, the more you start to notice that nothing is being exaggerated or forced. It just keeps things in check and lets the rest of the chain come through.

Verdict

The SU-2 isn’t going to be for everyone, and that’s pretty clear from the moment you look at the input selection. No USB means it’s not the most convenient option for a typical desktop setup, and if you’re coming straight from a laptop or PC, you’ll need to work around that. On the other hand, if you’re using a CD player, a DAP with coaxial out, or a proper digital transport, it starts to make a lot more sense.

Once it’s in the right system, though, it’s easy to appreciate what SMSL was going for here. It sounds clean, composed, and quietly capable in a way that doesn’t try to draw attention to itself. There’s no obvious colouring or forced detail, just a stable and well-resolved presentation that holds together over longer listening.

At around the $100 mark, it also ends up being one of the more affordable ways to get a proper balanced XLR output into your chain. It’s a bit niche in how it needs to be used, but if your setup lines up with what it’s designed for, the SU-2 makes a strong case for itself.