SMSL DO300 DAC Review

The DO300 is a new Digital-to-Analog Converter (DAC) from SMSL and it features the latest ESS flagship DAC chipset, the ES9039MSPRO. The unit comes in at a retail price at $549 and is available to order from our friends at Aoshida Audio. (

The product was provided by Aoshida for this review. As per usual, the review is my own set of impressions, and my link is unaffiliated.

I have recently reviewed the whole fleet of the SMSL DO and HO series DACs and headphone amplifiers, starting with the small and solid 100 series, and the middle 200 series. The 300 series, here, does not currently have a matching headphone amplifier, and I was told there are no current plans for a release of a HO300. That said, the HO200 should stack perfectly with the DO300. I still use the DO/HO100 series daily at work, as it has plenty of power and its compact size makes it a nice desktop compliment to my laptop and monitor for work use.


The DO300 has a similar look to the DO200. In fact, visually, its almost indistinguishable if it wasn't labeled with their model numbers. They both feature a small color screen on the right side, a multi-functional knob down the center, and the same set of input/output ports on the back, in the same exact locations.

This includes XLR and RCA outputs, and a variety of different inputs: AES, I2S, Coaxial, Optical/Toslink, and USB-A. In addition, there is a bluetooth antenna which has the latest Qualcomm Bluetooth 5.0 standard, and allows for LDAC, AptX-HD,  AptX, AAC and SBC formats.

Under the hood, there are a few new upgrades. The biggest change is the aforementioned DAC chip. This SMSL unit is built upon the ES9039MSPRO DAC chipset, the newest flagship from ESS. In addition, the unit employs 11 op-amps for output to the RCA/XLR ports and eventually to your amplifier.

This unit also features MQA decoding support, and will light up blue or green when activated.

Firmware Features

The color display can be controlled by the multi-functional volume knob, or with the included remote. I prefer navigating this with the remote, as it makes it quite a bit easier to use, as there are quite a bit of different options to play with.

The menu is the same as the DO200 MKII that I reviewed. Users can navigate through menus to change inputs, outputs, variable or fixed volume mode (preamp), jitter control (DPLL), dimmer, brightness, and most importantly to me -- PCM and DSD filters, and the SMSL's audio Sound Color menus.

The digital filters include 8 ESS Sabre filters to choose from:
  • Filter Off
  • Minimum Phase
  • Apodizing
  • Linear Fast
  • Linear Slow
  • Minimum Phase Fast
  • Minimum Phase Slow
  • Low Dispersion
The unique one that I don't remember seeing before is Filter Off. I didn't know you can disable over-sampling on a Delta-Sigma DAC, so this was an interesting one to see and to play with.

For the Sound Color menu, there's an addition series of filters:
  • Standard (off)
  • 3 Levels of Rich
  • 3 Levels of Tube
  • 3 Levels of Crystal
Each of these, I presume, plays around with EQ and phase to provide a different type of sound that was subtle, but distinguishable sometimes.

Sound Impressions

For this review, I primarily listened with my Hifiman Susvara headphone through the Bakoon AMP-13R amplifier. My normal day-to-day DAC in this set-up is the Holo Audio Spring 3 KTE (with pre-amp module), which is an R-2R resistor ladder DAC as opposed to the Delta-Sigma chipset-based DO300 DAC I am reviewing here.

My high-level takeaway here is that I actually really enjoy using the DO300 DAC quite a bit. It presents an alternate listening experience to my more analog sounding Spring 3 KTE, and for being a more precise listen, the DO300, has a very smooth overall sound. 

In many ways, going to a relatively lower budget DAC with a D/S chipset implementation can have a brighter and more sharper type of sound. This, of course, isn't always the case. I really enjoyed Audiolab's use of the old ES9018 DAC in their A6000, and found that they smoothed out all the glare issues normally found one of those older Sabre DACs.

With the DO300, there's a lot of play here that you can customize how you want the DAC to sound, with its selection of 8 filters and 10 coloring options. I found using Filter Off (No Oversampling) to be my favorite but I was perfectly happy with the traditional Linear Fast and Linear Slow filters too. For coloring options, one of the Rich or Tube, or default Off was quite enjoyable. The Crystal options made it sound, as you would expect, a little more bright and gives a sense of more detail, but at the expense of being a bit fatiguing.

The DO300 is very resolving, and clear, but does not have what I consider a sense of faux-clarity, where excessive treble/brightness makes details more forward and sharp. Instead, I found a sweet treble that I thought mixed well with the overall sound.

The DO300 is punchy, and layered. It's punchier than my Spring 3 KTE, which is a little more warm and soothing versus ultra-neutral. Characteristically, I find the differences are most apparent when you listen to how strings resonate, and even their base frequency note sounds different between the two. The Spring sounds natural, but slightly dampened in a way, but resonates more organically, while the DO300 has a more defined and incisive strike, with a resonance that also has this brighter hue to it that isn't quite digitized, but isn't also a warm, soothing fireplace feel either. It's a bit hard to fully describe these general differences between the R-2R and D/S sounds in just words, without listening to it.


SMSL's DO300 is a very nice DAC that makes use of the latest from ESS with their ES9039MS PRO DAC chipset. This little unit has a variety of sound tuning options within its simple and colorful display that is easy and intuitive to control with the included remote. 

I was happy with the overall reference sound, with good resolution, punchy bass, and sweet and smooth treble. For a well-measuring, reference-type DAC, this one checks a lot of boxes for me in a small desktop-sized box.

Purchase Link:


  1. I have a problem with this dac ( had a similar problem with DO200 MKII). Using a CD transport or a CD player connected with spdif coax input I can not use "sound color" if PCM filter is off, because the sound is heavyly distorted. No problems with usb or Bluetooth connection. (With DO200 MKII the problem was solved with firmware upgrade, but the sound was not the same as before...but worser, bad Soundstage and harsh trebles...)


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