SMSL D-6s Balanced DAC Review

[amirm]

This is a review and detailed measurements of the SMSL D-6s balanced stereo DAC with Bluetooth support. It was sent to me by the company and costs US $199.

I was pleasantly surprised with the new industrial design which while minimalistic, manages to impress with its modern style. Love the matt diffuser in front of the white LEDs. And the elevated panel gives a distinct and dare I say, luxury feel. A remote control is provided which makes navigation very easy.

Very nice to have built-in power supply in such a small package:

SMSL D-6s DAC Measurements
Let's start with our usual dashboard with level adjusted to near 4 volts using XLR output first:

Distortion products are at -140 dB! Incredible. SINAD as a result is dominated by noise, and landing the D-6s in our top 20 chart of all DACs tested:

Even RCA output is impressive and fully audibly transparent:

Output can go to 5 volts using XLR giving us a bit more performance still:

As noted, SINAD is determined by noise since distortion component is so low:

For compatibility with stereophile magazine measurements, here is the 60 Hz performance:

Despite having a "punishing" load of 600 ohm as JA calls it there, D-6s sails with distortion at whopping -120 which I am confident bests anything stereophile has ever tested.

Back to our own tests, linearity is nailed:

As is jitter across all three interfaces:

Multitone performance makes the company proud:

We are some -135 dB in some of the frequency range!

EDIT: Forgot to post the IMD test:

Here are the usual filter and frequency response tests:

Using default F2 filter, we get excellent performance in our wideband THD+N with a slight rise at the upper end:

Conclusions
I pride myself in always finding something to complain about in a review but I have nothing for you here. Price is right. The look is right. And performance is top notch regardless of price. I always recommend balanced DACs and here is your chance to get one without any compromise.

I am happy to recommend the SMSL D-6s DAC.

Manufacturer Specifications:​

• Inputs: USB, optical, coaxial, Bluetooth
• Outputs: RCA, XLR
• THD+N: 0.00006% (-123dB)
• Line output amplitude:
  • XLR: 5Vrms
  • RCA: 2.5Vrms (1.13Vrms)
• Output impedance: XLR: 100Ω
• Dynamic range:
  • XLR: 129dB
  • RCA: 126dB
• SNR:
  • XLR: 129dB
  • RCA: 126dB
• USB transmission: Asynchronization
• USB compatibility: Windows 7, 8, 8.1, 10, 11 (needs driver); Mac OS X 10.6 or later, Linux (driverless)
• Sampling rate and bit depth:
  • USB:
    • PCM: 44.1-768kHz (32bit)
    • DSD: 2.8224-22.5792MHz (1bit)
    • DoP: DOP256
  • Optical/coaxial: 44.1-192kHz (24bit); DoP64
• Bluetooth version: 5.1
• Bluetooth codecs: SBC, AAC, aptX, aptX HD, LDAC
• Power consumption: <10W
• Standby power: <0.5W
• Size: 150x42x128.5mm (WxHxD)
• Weight: 1.57lbs (0.71kg)

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As always, questions, comments, recommendations, etc. are welcome. Click here if you have some audio gear you want me to test.

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[Jas0_0]

Great to see the price of SOTA coming down and down. Will be interesting to see how competition changes things and whether the focus will switch to more features. The DAC is a great point in a system for DSP.

 

[JSmith]

Yep, nothing wrong here and priced well too. Thanks for the testing @amirm and to SMSL for sending one for testing.

ES9039Q2M
XMOS XU-316


JSmith

 

[Sokel]

Yep, nothing wrong here and priced well too. Thanks for the testing @amirm and to SMSL for sending one for testing.

View attachment 319867


View attachment 319868

ES9039Q2M
XMOS XU-316


JSmith

This all linear PSU* and the melf resistors at the audio output will make "old" audiophile souls happy

Thanks Amir!

Edit:*Nope,SMPS

 

[TonyJZX]

the alternative to this is the AL200

i like how the green bluetooth board is stitched into the black main pcb

 

[totti1965]

Oh, wow!

 

[Anthony T]

I haven’t really been a fan of S.M.S.L. thus far, first It was looks and then their display grated with me but this ticks all the boxes. Very nice all round.

 

[somebodyelse]

This all linear PSU

The 400V cap makes me think SMPS

 

[Talisman]

Thanks for the review Amir.
Economical DAC, with commendable performance and with balanced outputs.
However, I really don't understand, on a commercial level, why some companies continue to throw up dac after dac after dac in the market with practically identical performances, the same functions, the same inputs/outputs.....

 

[ALaylowguy]

people, this should be the result of the SOTA war, great features with great price not just churning out Pro Max series all the time.

 

[TonyJZX]

since this one was announced a few weeks ago, smsl released the DL300... to what need, i dont know...

also to me the display on this is the clock radio segment type which kind of looks shit compared to the OLED ones on smsl's own cheaper models

 

[Rja4000]

Thanks for this review.
Impressive results !

And this is (one of) the cheapest DAC with LDAC capability.

A quick check of the LDAC performance on those LDAC-capable DACs ?

 

[amirm]

The 400V cap makes me think SMPS

It has to be since it has universal input voltage range. It looks so simple though.

 

[Sokel]

The 400V cap makes me think SMPS

Yep,you're probably right,there's things missing there to form a linear one.

 

[ocinn]

This is just further proof the dac problem has been essentially solved.

Next up is perfecting low cost, high power and efficient amplification (this is essentially the benchmark in my eyes in terms of cost:sizeerformance ) and then, reducing distortion and power compression on speakers/drivers, as ultra performant gear is pretty irrelevant when your speaker can’t clear -50 THD+N.

Also would like to see a shift outside of the 4v over XLR standard. In my world, I regularly operate with +20dbu signals between gear that is designed to TX/RX it. This allows me run far lower gains on amps, which in turn drastically lowers the noise floor over operating in a strict 4v ecosystem.

I hope home audio/hifi world catches on to the benefits the pro world (esp studio) have been enjoying for years.

 

[DSJR]

Apart from the odd display top standing proud of the top cover, this little box looks to be end game for most of us really if a dac is all that's needed.

 

[Michael Fidler]

Just absolutely fantastic to see products like this coming in at such competitive prices. Making me feel more than a little self-conscious and in need of a better distortion analyser.

I love the understated black enclosure style alongside the 7 segment display under the smoked acrylic. Very reminiscent of VFD displays without the horrors that they entailed and doubtless much longer lifespan.

Also great to see such good performance with an in-house (as opposed to off-the-shelf module) SMPS design, especially without what seems to be much in the way of shielding and not a sign of any power supply artefacts. Whoever did the PCB layout must have really known what they were doing.

 

[JeremyFife]

Another good DAC ... although to be fair that's a pretty startling price/performance result ... nice

Some previous budget SMSL DACs have exhibited 'pops' and noises when the source resolution changed. No mention of that here or in comments, so perhaps that's solved too now.

 

[Michael Fidler]

Yep,you're probably right,there's things missing there to form a linear one.

It might be a 'double-insulated' version without the ground tab on the IEC power connector being connected to anything, alongside the X class EMI/RF supression cap connected across the HF transformer (next to the feedback optocoupler). Quite a strange design choice seeing as it would have been possible to easily use the ground from the IEC connector for what might ultimately be better RF performance and stronger decoupling from the mains (the suppression cap will allow quite a bit of leakage - at least from what I've seen in the past), which could be completely mitigated by grounding the low voltage side of the power supply...

Nonetheless the performance is excellent so I really can't complain, although I have a feeling that if the unbalanced output was measured with a cable longer than a meter or so we might see evidence of small mains leakage currents across the suppression cap. Having said all of that, it's highly likely now looking at the PCB layout that the ground is being used as there are pins front the ground that go into the PCB and the tap appears to be possibly just a way to connect it to the chassis, in which case all of what I've just said my be disregarded!

 

[Graham849]

This finally goes beyond the SMSL DO100 feature set for me. If only a hdmi input. SMSL have nailed it once again, great review Amirm.

Perhaps a DO100 mkII is around the corner?

I am guessing there is no actual auditory improvement over the DO100, but good to know a replacement is available.