Michael Piskor 2020

SMSL M400 Review

The SMSL M400 is a desktop DAC featuring an AKM AK4499EQ chipset, LDAC Bluetooth, MQA, and a fully balanced analog output. It is priced at $809.

Disclaimer: The SMSL M200 sent to us for this review is a sample in exchange for our honest opinion. We thank SMSL for giving us this opportunity. 

To read more about SMSL reviews on Headfonics click here.

Note, this review follows our new scoring guidelines for 2020 which you can read up on here.

You can get clinical tonality and not have a painful wince factor. You can get a softer impact and smoothness while remaining clinical and accurate overall. SMSL just proved it. Facts, all day long, baby!
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Reader's Score

Truth be told, I enjoy it when companies actually innovate and provide products that compete with much more expensive variants…but while retaining a lower price tag.

We call that “punching above its weight class”. SMSL’s M400 DAC is a true monster at $809. I have a lot to say about this one, so let me not waste your time further and simply get right into the review.

Packaging & Accessories

Nothing fancy in the way of the box, beyond a cloth covering and some inserts, you will get the power cable, some printed information, and the USB B-Printer style cable.

Sadly, no interconnects were included. I suppose if you are buying an $800+ DAC or Amp, you probably have your own cables anyway. If not, head over to Monoprice or something and grab some standard RCA or XLR cables for yourself on the cheap.

Each time I say that everything you need to enjoy the product should be included and to get started right away, I get slammed with others telling me they disagree. I just prefer my near thousand-dollar purchase to come with some interconnects, but if so, many others disagree with that sentiment, so be it.



Damn sexy little DAC here, if I do say so. The build quality is superb, solid metal housing with a gorgeous reflective glass top that was tempered.

Look, there are attractive and well-built DAC’s out there, but then there is this M400 on another level. I would rate this extremely high in build quality and the best build in a DAC I have seen that wasn’t solid metal all around.

The inclusion of something like glass on the top is pretty cool and gives style points. The unit is hefty and very dense feeling, like a lead weight in your hands.

Surprisingly, the DAC is not noticeably big. I consider it mid-sized. Bravo to the build quality of the volume knob as well. I am a bit sad (not really) because it comes with a remote control that makes sure I do not get to touch the M400 often to feel the excellent build offered.

The color front panel is a nice touch, glad to see it is not trash monochrome in 2020. We put people on the Moon in the ’60s. We can get cheap color panels on DAC’s without them being ungodly expensive.



The SMSL M400 includes standard RCA, XLR, HDMI, Optical, as well as Bluetooth via a removable dongle antenna. Beyond that, MQA and native DSD512 is supported with up to PCM 32bit 768kHz compatible also.

In my testing, I found that I preferred the USB connection over anything else. Typically, Optical is the output of choice. But, in this case, I preferred the USB option with my laptop inventory SSD as the source for music files. More on this in a bit though.

For now, the M400 has everything you would want as a raw and pure DAC option for a source. This is not a DAC and Amp combo. This M400 is pure DAC only. You will need to connect the M400 to an amplifier for your speakers or headphones via your pick of its output types.

The more I talk about DSD, the more I feel absurdly overwhelmed by it. With more DSD available now, I see the value of it. I never felt the need to upgrade or purchase beyond DSD64.

You might coax me into a DSD128 purchase if it were on sale. I do not see the need for DSD values beyond that point. To have DSD512 as the new standard is quite amazing, it will likely not stop me from shaking my head at its absurdity for a few years to come. It is great to have the option to go that big.


Sound Impressions


The M400 uses the AKM’s new flagship AK4499 DAC chip and it sounds amazing. Let us just put it that way. It is one of the best sounding DAC’s sub-$2000 I have heard in my life.

In raw quality and purity, it is excellent. Top Tier. But, subjectively, I dislike neutrality and clinical accuracy. True, there are times where it is required or some tracks that just sound better with that tonality. But my personal preference is warmth and velvet low end over clinical.

Now, having said that…as a reviewer, I will always give credit where it is due. The neutrality factor on the AK4499 is absurdly fantastic. If you want a clinical and accurate sounding DAC, this is it.

Do not even bother right now sub $1000. It is generally considered, at least right now and by many of my peers and I, to be the top pick of the litter for the price.

My personal preferences and the listeners who like warm sounding experiences will not feel at home with this one. However, I doubt anyone will ever say it does not reflect a hyper-purist sound type when you listen to it. It surely does.

Tone Pairing

This is a make or break product. By that, I mean if you inject this M400 into your rig as a Source, be damned sure your pre-amp/power amp/speakers are neutral for the most part. Otherwise, you have just sullied them entirely.

You do not drop a warm sounding DAC into the mix with an all clinical sounding amplifier and headphone/speaker combo. So, do not do the reverse with this neutral M400 into a warmer rig. Make sure you are tone matching properly. Otherwise, you have wasted your money.

Now, of course, as a steppingstone, or if you happened to find that the M400 tames the harshness of your speaker or headphone, then go for it…it can do that. The M400 is clinical in tone, but smooth in physical tactility and strike factor. We can call that a “polite” sound.

The physical strike wince factor is very tame and low on this model, which usually does not go hand in hand with very pure sounding neutral equipment. But this M400 offers it anyway. You can get an exceptionally smooth feeling sound while retaining an excellent purity factor that is uncolored top to bottom.

It is not common, but other products lately have been designing their products like this. Side by side with the classic Objective2 DAC, you can immediately feel a glazed slickness fall upon every single thing you listen through the M400.

Where the 02 is extremely harsh sometimes, that same track will sound much smoother and softer in dynamic kick potential on the M400. Rig pairing is so important.

Bass and Mids

I am combining these two sections because this DAC is so pure, that both the bottom end and the midrange reflect the traits of the other frequency band…neigh perfectly. What the hell does that mean?

Well, the DAC is so clinical and smooth, that I do not notice a bass bump at all and there is no blur between the low end and the midrange. They flow so seamlessly between each other that I feel like the midrange and bass are one and the same and that is a super rare quality to house.

Typically, you do not hear that in DAC’s unless they are a few thousand dollars in cost and beyond. This M400 is not boosted but can be if you use the right DSP.

And I say DSP and not EQ there because DSP’s like Foobar2000s realbassexciter is just so omnipotent by comparison to a standard EQ setup system, that it becomes unfair to speak them in the same sentence.

EQ, that standard dialing often found in some sources, just does not cut it anymore. There is only one EQ system out there I defend to the death, which is Cowon’s JetEffect. It is the most powerful and complex with the bass potential you can drop in and out of.


Boosting EQ

With that said, the M400 requires a fair bit of boosting on the low end to get it to sound bassy. However, it remains super clean throughout. The midrange does not blossom either, it is flatter or more neutral in physical location than not. Nor overly forward, not recessive. I would not call it hyper-engaging.

However, it is an extremely well-formed and realistic feeling with the right amp behind it. Paired with the Feliks Audio Euphoria ANV Tube Amp…wow. If you like Jazz and standards from the 40s and 50s, this is your dream rig.


The entire top end has a glistening effect to it, a gentle and stunning luster. That sparkle effect, dream chased for years by me, is found here.

Similarly, to some headphones, like the AKG K267 Tiesto’s famous stunning treble experience, this M400 portrays the same sense to my ears. It is exceptionally soft, very tame and housing just a gentle brightness to it that never gets harsh in physical strike factor.

Tonality wise, the experience is again very, very pure sounding. I consider the treble noticeably more reserved in quantity than most “neutral” DAC’s out there. I think it was purposely set up that way to retain a soft and elegant sound. Elegant…probably the best term I can describe for this M400.

If you are looking for a truly accurate top end, this might require a little boosting to acquire. I believe the stock sound is more tamed and reserved on the top side, while the bass and midrange are untouched.

I feel SMSL wanted you to relax at all times, enjoy the clinical accuracy of the sound tonality, but never wince and shoulder shrug and say “ow!!!” when someone hits a cymbal or when a harsh piano key strike is pipped in the track.


If there is a weak link in the chain, the only one I could find is overall spaciousness in the imaging void. This DAC is intimately setup, at least, in terms of physical location and presentation. The bubble space provided is extremely well shaped, which is one hell of a realistic bubble if you ask me.

The problem is overall vastness and width. However, a small circle/sphere in shape can still sound very realistic in tactility and density factor, which this DAC has in abundance.

However, A/Bing with the Burson Conductor 3, you can clearly see that team Burson offers a noticeably more expansive sound. Both offer a similar tendency in the overall stage forward depth and potential layering.

You can really hear this with great speakers and not so much with any headphones I was able to test with. The difference in dynamic layering in a sense of stage-forwardness is sublime. Dare I say the best in a pure and raw DAC only option I have ever heard under $1000.

Burson’s Conductor 3 is both a DAC and Amp, also costing a bit more than the M400, so this is to be expected to be roughly comparable in stage depth. But no doubt really, the Conductor 3 shells out a more widened approach to the sound.

If anything, the Burson is noticeably warmer and has a slower roll-off damned near everywhere. That, vs the M400 that is lightning fast and much more clinical in its approach.


Look, at this point, you should know the M400 is one of the best pure 100% DACs sub-$1000 out there, (at least that I’ve heard), so it is only natural I am going to pipe this bad boy into some serious headphone amps.

Take the Feliks Audio Euphoria ANV Tube Amp ($2600) and the Little Dot (roughly $1600). And in turn, going to just go ahead and feed that into the $1600 set of Fostex TH909 open backs, as well as Swan Song Audio’s bass titan open-back headphone (roughly the same price). So, what are my thoughts?


Feliks + SMSL M400 + TH909

Well, dear God…there must be a God to allow for this type of synergy. The Feliks amp is hyper smooth…and when I say that, I mean laser-focused like a particle accelerator beam that is pristine and just stunning to look at as it cooks instantly through a solid piece of metal, like Superman’s laser vision.

The SMSL M400 is also very slick and polite, perfectly meshing with the Feliks amp. In regard to purity, it is off the scales. I have not pushed the TH909 yet with a really clinical DAC, as I prefer the warmth it can achieve with the Burson line. But holy smokes…the TH909 was clearly made for this type of rig.


Burson Conductor + M400 + TH909

So, the Conductor 3 being a DAC and an amplifier combo in one lets it operate as a pure amplifier too, sort of. I can output the M400 directly to the Burson Conductor 3 and use the Conductor as the amplifier, the SMSL M400 as the Source DAC.

The result is strange and not something I recommend. The rig is a total bust and they do not, subjectively, pair with each other without serious EQ and DSP usage.

The Burson is noticeably warmer and larger, so opting to drop the M400 in there will reduce the potential imaging prowess portrayed at the end of the chain in your headphone or speakers.

Beyond that, the DAC in the Burson sounds remarkably similar in quality to the M400, so there is no reason to pair these together. Just thought it was fun. It makes the TH909 sound bassier and a little restricted in the size of the stage vs what I am used to just using the Burson + TH909 alone.

SMSL M400 + Little Dot LD H1 + TH909

This is a great starter build if you cannot go bigger with the Feliks amp or something in excess of the price of the M400 at roughly $800. The Little Dot is less reserved in physical appeal vs the Feliks more smoothed approach. Meaning, the Little Dot is a little more raw, more sterile feeling.

A little brighter up top as well and that is something I prefer not to say near the Fostex headphone lineup. They are usually treble sensitive and can get bright fast. But the TH909 is a little different than the others in the Fostex family, it is more reserved up top and tamer. Softer, maybe, less bright. It pairs less well in the treble response of the Little Dot than it does the Feliks or just the Burson alone.

However, if you like that tube sound, this is a great $1000+ pure amplifier. I think this one pairs better with my Dan Clark Aeon2 more than anything else.

The M400 deserves something a little better than the Little Dot, and you can hear the fidelity difference swapping the Little Dot to the Feliks, while the M400 is still active and sourcing your music.


Our Verdict

No doubt in my mind, this is one of the best and most well thought out DAC’s sub $1000 in the world right now.

Do not even listen to me, feel free to YouTube, or read other reviews that also confirm this. I agree with them. It is a great deal for a purist DAC option, but also one that does not slam your ears with impact and harshness.

You can get clinical tonality and not have a painful wince factor. You can get a softer impact and smoothness while remaining clinical and accurate overall. SMSL just proved it. Facts, all day long, baby!

SMSL M400 DAC Specifications

  • D/A Chip: AK4499EQ
  • Contains XMOS XU216 Chip
  • Contains 2 ACCUSILICON Crystal Oscillators
  • Supports MQA Decoding
  • Bluetooth 5.0 Capability
  • Supports UAT: 24bit/192kHz
  • Supports LDAC: 24bit/96kHz
  • Supports aptX HD: 24bit/48kHz
  • Supports AAC: 16bit/44.1kHz
  • DSD512 Native
  • PCM 32bit/768kHz
  • SNR: 131dB
  • THD+N (A-weighted): 0.000058% (-124dB)
  • Dynamic Range: 131dB

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