Review: S.M.S.L D300 Digital to Analogue Converter

S.M.S.L D300 Digital to Analogue Converter
A DAC Out of the Ordinary
By Steve Graham


Let me start out by describing what the D300 isn’t, doesn’t have or won’t do:
-It isn’t physically imposing.
-It doesn’t have slabs of sculpted aluminum formed into a jewel-like case.
-It doesn’t have a built-in headphone amp.
-It won’t impress your audio buddies with its size or looks.
-It won’t crush your budget (as long as your budget stretches to $500 CDN).
-It won’t decode MQA streams (who cares?).

What the D300 is, has or will do:
-Built-in power supply (no wall wart or phone charger needed).
-Coax, optical, USB and Bluetooth inputs.
-RCA and balanced XLR outputs.
-Selectable digital filtering options.
-A remote control

-Volume control adjustment from the front panel or remote (can be defeated).
-Easily navigable colour display, though it is a bit small.
-ROHM Semiconductor flagship DAC chip (also used on some mega-bucks Luxman gear).

Chips ahoy? I don’t subscribe, like some do, to selecting a DAC by its converter chip. There is so much more that determines a component’s sound than one part. Some think all DACs with AKM chips sound bad. Others only want DACs equipped with Sabre chips. For a third bunch of audiophiles only Burr-Brown DAC chips will do. All that said, it was the DAC chip in the D300 that caught my attention. Made by Japanese chip maker, ROHM Semiconductor, the MUS-IC BD34301EKV has not been adopted by many digital player or DAC manufacturers. In fact, from what I’ve been able to discover, the only other audio company to use this chip is Luxman, in their most expensive CD/SACD players.

First, a little housekeeping

I can be as biased as the next audiophile. Do I let that intrude on my reviews? I try not to. For example, some of my biases relate to specific tube types. I’m not keen on 12AX7/ECC83 tubes but I’ve heard gear using them that sound very good. Ditto 12AU7/ECC82 tubes. I also don’t like “warm” sounding gear when it comes at the expense of bass extension or treble clarity. I don’t like fulsome-sounding bass if the cost is ponderous pace and drive. I can’t take high frequency extension and detail that crosses the line into harshness and aggression. That will set my teeth on edge and kill musical enjoyment. I believe I communicate my preferences so readers can either get on board or take them with those grains of salt. The only thing I have are my impressions and perceptions, which I try to convey as honestly as I can. You may not agree with them but I try to state them as clearly as I can. If a reader’s priorities are different than mine, hopefully she or he can see around my biases and deduce what’s pertinent to their taste.


More housekeeping (Raspberry Pi)

Head slap number one: I keep learning new things with regards to the Raspberry Pi used as a music streamer. I’d reported that I couldn’t get USB DACs to lock reliably to the Pi. I recently realized that a USB DAC must be connected to the Pi while one goes through the setup. It can’t be plugged in after the fact as I had been doing. Doing it the proper way, my old but still faithful Meridian Explorer II DAC, connected without a hitch. Head slap number two: A second issue I’d reported were problems regarding the use of Western Digital USB drives with the Pi. I like to keep several data backups of my music library on USB drives and I rotate these between two players and secure storage. I’ve discovered that swapping USB drives on a Pi running piCorePlayer and Logitech Media Server isn’t just a matter of plug and play. Every time a drive is changed the software must be instructed a new drive has been “mounted”. The previous sentence will make sense to those familiar with the piCorePlayer and Logitech Media Server ecosystem. So, no problem with WD drives. The issues I encountered were down to me, not WD.

Wide-angle lens distortion makes the D300 look much bigger than it reality is


Back to the DAC

The D300 is tiny. Not quite Schitt Modi tiny, but at a little over eight inches wide and less than two inches tall the D300 is not even half the width of so-called, normal components. The case is bent and folded sheet steel, except for the front panel which is anodized aluminum. The feet are of the rubber stick-on variety. It comes with an IEC power cord, a generic USB-A to USB-B cable, the aforementioned remote and a Bluetooth antenna. The instruction manual is a bit on the basic side and could be more detailed.

The colour OLED display is small but has decent resolution. Setup is reasonably intuitive. The dimmable display indicates selected input, sampling frequency and when the volume-adjust function is activated (controlled by the front panel knob or the remote) a brief display of the setting is shown when changing volume. This allows the D300 to be run straight into a power amp or powered speakers. In low light it is difficult to see the front panel markings. The buttons and knob are nearly flush with the front panel too, which makes finding them a bit hit and miss. Once set up though, the most commonly used adjustments can be made with the remote.

The D300 will decode PCM up to 768 kHz, DSD up to 512 and a whole alphabet soup of Bluetooth codecs. As well as controlling volume, the remote can select inputs and do a few other things too. I did a bit of digging on the ROHM website and located the BD34301EKV data sheet. When playing PCM files there are two digital filter settings. Without delving into it too deeply, there is a sharp roll-off filter with flat response to 20 kHz and a slow roll-off filter that is down a few dB at 20 kHz. This roll-off is most pronounced with 44.1 kHz sampled data. The higher sampling rates have progressively less roll-off in the audio band. The impulse response is affected by these settings but no details were provided. Typically, digital filters that trade rolled-off frequency response do so for more analogue-like impulse response.

There are other filter settings as well when playing DSD files. I had a peek inside and it would appear that concessions made on the enclosure have been more than compensated for on parts selection. The aforementioned DAC chip is rumoured to cost significant multiples of the more common D to A chips. Though mostly surface mount components are used, a few Nichicon audio grade, through-hole capacitors, can be seen on the circuit board. The cost for all of these features and connectivity? About 500 dollars Canadian, a little less than $400 US for USA-based audiophiles. Like a lot of Chinese-branded components, distribution is semi-direct through the popular online sellers. Why would I pay 500 bucks for a Chinese DAC? Several reasons. I was not entirely happy with the functionality of the streamer/DAC in my living room system. To power both the living room amp/speakers and the adjacent kitchen amp/speakers I require a DAC with both RCA and XLR balanced outputs. I saw a couple of D300 YouTube reviews that intrigued me. had a returned D300 for slightly less than $400 CDN. I also got an additional 50 bucks off by applying for their credit card.


System Particulars

For evaluation purposes I primarily ran the D300 in my main system. (NAD 50.1 digital player, PS Audio DirectStream DAC, ARC REF3 line stage, ARC REF110 power amp, Spendor D9 speakers, PS Audio AC Regenerator). If I had to characterize my PS DirectStream DAC, I’d say it is neither warm-sounding nor cold-sounding. Neutral with good dynamics and detail but not harsh. Its level of detail retrieval can be a liability on substandard recordings where engineering faux pas are all too obvious. That being said, on any recording of at least reasonable technical quality or better, its sound is very compelling. I used the D300’s XLR outputs into my all-balanced ARC gear. An approximately 60-dollar Canare digital cable from HAVE connected my NAD 50.1 to the D300. Yes, I know, cables matter, especially in the digital domain. But nobody will purchase a multi-hundred-dollar cable for use with a five-hundred-dollar DAC.

The SQ (Sound Quality)

Oh my. The D300 sounds way too good for a 500-dollar ($400 US) DAC. If your frame of reference for an add-on DAC is something in the 100-to-200-dollar range, the D300 will likely be a revelation. Compared to my ~$7,000 PS Audio DAC, the D300 was a revelation. Sure, the $7,000 DAC is better but the D300 is eminently enjoyable. First of all, the high frequencies don’t grate. They are smooth but detailed, dependant on source material of course. It passes my Blue In Green test for high frequency detail. This is the test I give every component with regards to resolving the delicate brush work on that track of a 24/192 Kind Of Blue download.

Also played were a few tracks I customarily use to judge vocal performance. The D300 didn’t quite have the hear-into presence and articulation of both female and male voices exhibited by my more expensive DAC. Keep in mind that these were back-to-back comparisons of a multi-thousand-dollar component versus a five-hundred-dollar one.

I’ve been in a bit of a guitar hero mood lately and decided to give these two classics a spin. When I say spin, I mean the hard drive in my NAD 50.1 music player. Into The Purple Valley was my introduction to Ry Cooder when it was released back in 1971. A friend had bought the LP and though not to my taste back then, I’d never forgotten it. On a whim I bought the CD a few years ago and enjoy it immensely. The D300 in no way dilutes my enjoyment of this disc, even when compared to its more expensive stable mate. Bop Till You Drop is a different kettle of fish. It bears the somewhat dubious distinction of being the first digitally recorded, major label release. At the time, 1979, the clarity of the LP release was a revelation. Little did we know then, that the digital “clarity” first heard here would come back to bite us later. Bop’s transition to CD won’t make anyone think of, “Perfect Sound Forever”. I enjoy the music on Bop, but it’s often a question of how palatable does a piece of gear under audition make this disc. The D300 doesn’t make it sound any worse than it already is.

On different tack, this Telarc release from 1984 was state of the art for its time and has aged better than many digital recordings. That’s not to say that a remastering wouldn’t go amiss, though it is unlikely as Telarc was gobbled up by another record label many years ago. Playing this recording is where the differences between the D300 and my PS DAC became most apparent. I find one of the differences between good and great gear is how they respond to loud, complex musical passages. Though the S.M.S.L DAC is decent when the music gets intense, it sounds a bit strained compared to the PS DirectStream. The PS sails through without breaking a sweat, whereas the D300 is working hard and sounds slightly congested. I did most of my listening with the PCM filter set to Slow Roll-Off. The sonic effect when switching to the Fast Roll-Off filter was very subtle. I found it most noticeable on the Jongen disc and even then, the differences were difficult to perceive. I couldn’t hold my hand on my heart and swear to it, but the high frequencies with the Slow filter seemed slightly less strained. At the same time, initial note attacks seemed slightly sharper and more dynamic and startling in Slow Roll-Off mode. The Jongen also highlights the greatest disparity between the two DACs. The PS DAC paints a noticeably more detailed and specific soundstage. Instruments and voices seem a bit stuck to the speakers when using the D300 whereas the PS DAC spreads them out between my Spendors. Could this be down to the digital interconnect? Your guess is as good as mine, but I was surprised by the difference a digital interconnect made in my Audioquest cable review from 2020.

Always a good time, SRV will get the joint jumpin’. Both DACS exhibit good forward momentum and convey Stevie’s propulsive playing. The production is bright, somewhat compressed and not very subtle. Though probably not the best choice for discovering minor differences the D300 captures the sheer energy of SRV’s playing as well as the expensive PS DAC. These, along with the Cooder tracks, highlight the D300’s small but noticeable mid-bass bump. Though not exactly accurate, in comparison to the DirectStream, there is no penalty for it. Oftentimes a little goose in this part of the spectrum results in a lack of pace and drive. Not with the D300, as far as I can tell. In general, the D300 gives up very little in the pace and drive department compared to the approximately fifteen times more expensive PS DAC. On all tracks I threw at the D300 it was never less than engaging and, in most cases, just plain fun to listen to.

Am I one of those DAC chip fanciers I disparaged earlier? Quite possibly. The D300 might give the chip-fanciers a new chip to fancy. I’d sure like to hear this DAC chip in a high-end, no holds barred DAC.


I connected the D300 to one of my Raspberry Pi’s USB sockets. I’d previously powered down the Pi and removed and re-flashed its SD card containing the operating system. I powered up the D300 first then the Pi. (See head slap number one above.) I used the free version of the Volumio OS this time around. Volumio is much easier to set up than the piCorePlayer OS I use in another system. As far as I can determine, the free version of Volumio doesn’t support any of the streaming services. A paid subscription of approximately three Euros a month is needed to activate streaming. The free tier will allow internet radio streams, which is fine for the system my D300 will see use in. Anyway, all fired up without a hitch and the Volumio-equipped Pi recognised the D300. I didn’t do any SQ evaluations in this system as it is optimized more for décor considerations than audiophile sensibilities. Suffice to say it works reliably, music flows and domestic harmony was not threatened. I didn’t try the Bluetooth input. I don’t have any DSD files so I wasn’t able to verify this feature. My PCM files top out at 24/192 and the D300 played these from both the NAD 50.1 and a Raspberry Pi 4B without a hitch.


(Please read below in the Comments for some not so happy postscripts)

Chinese HiFi gear, like China itself, have come a long way in a short time, politics aside. The S.M.S.L D300 is obviously a product developed by enthusiasts for enthusiasts. All of the differences I noted between the D300 and the PS Audio DAC are, for the most part, fairly subtle.

I suppose it’s the reviewer’s job to, if not exaggerate differences, at least shine a bright light in the cracks to determine strengths and weakness. During the review process I would listen to a few tracks with one DAC then switch over and listen to the same tracks with the other DAC. Though not a blind process, there were several switcheroos when after a minute or two I’d lost track of what DAC I had been listening to and wasn’t sure which one it was merely by sonic signature. I guess this says that even though the S.M.S.L D300 can’t run with the big boys it can at least give them a good chase. So, if you are pouting that your budget won’t stretch to the $2,000 DAC you fancy, don’t be glum. If you’re in a funk because the $1,000 DAC you’ve been lusting for is out of reach, don’t despair. For 500 bucks – 400 in the USA – you can have a DAC you won’t soon outgrow. It offers more than a taste of what the big, expensive DACs offer. If you buy it from Amazon and hate it you will be able to return it. Then someone else can do what I did, buy it at a discount.

Wishing everyone a happy and tuneful 2023.

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8 Comments on Review: S.M.S.L D300 Digital to Analogue Converter

  1. Bill Scofield // 2023/06/01 at 12:52 am // Reply

    Enjoyed your article. Found on my Google home page. Please let me read more articles. Bill in Calgary

    • Thanks for your comment, Bill. I’ll add you to our subscriber list for article notifications.
      All the best,

  2. Don Ivey // 2023/08/10 at 9:30 pm // Reply

    My D300 has developed a popping sound when a selection has a different bit rate than the previous one. If I cap everything at redbook, no pops, but anything higher causes pops. Any suggestions? Thanks.

  3. Steve Graham // 2023/08/11 at 9:01 am // Reply

    Thank you for your inquiry Mr. Ivey. I too have had problems with my D300. Just recently it would lock to data streams but no analog output. I’ll keep readers informed of my progress obtaining a warranty repair. Sorry I couldn’t be of more help. If you are within the return period you might want to send it back before a more serious issue arises. Regards, Steve Graham

    • Hi there, thanks for the review.
      Would we have any news what happened with the warranty? is ther eany update?
      Was it a hardware problem or a driver’s selection issue on pc or pi end?
      Finally any update about the pops and clicks changing bit rates?


  4. michael yankovich // 2024/01/30 at 5:49 pm // Reply

    Good afternoon,
    not sure if you can help me with this. Presently i am using a SMSL SU8 V2 dac with my speaker setup. Am i upgrading at all if i was to consider this D300 as a replacement, or am i splitting hairs? I appreciate your time and insight, and always enjoy the WOS reviews. Thank you,

  5. Steve Graham // 2024/02/14 at 11:29 am // Reply

    I emailed the manufacturer but they told me to contact the dealer I bought it from. The unit was bought from Amazon from a vendor called: *somthing*-CA. I won’t reveal the actual vendors name but the -CA gave me the false impression (silly me) that they were in Canada. The vendor is in China. After a few emails back and forth, the vendor was very prompt and courteous, trying a few resets the unit needs to be returned to China for repair. I must pay for shipping to China but not return shipping. I am undecided as whether or not this is worthwhile. I’m not trying to dis the manufacturer, they likely make many trouble-free products but it’s not as straight forward as obtaining service from a local dealer with a manufacturer located in or near your country or one that has a service network in your country.
    Perhaps I just rolled the dice and lost.

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