S.M.S.L D6s BALANCED DAC REVIEW

S.M.S.L D6s Balanced DAC costs less than £200 but can it hold its own with the more expensive DACs out there. Oscar Stewart finds out for HiFi PiG

S.M.S.L are quite a well-known brand in the audio world, they are based in Shenzhen, China and make a huge range of DACs, Amps, Headphone amps, and other source components. They make products to suit most budgets and, are known to make some great kit in the lower price bracket. 

In this review, I will be looking at one such product, a sub £200 High-Res DAC with balanced outputs. The D6s features an ES903Q2M DAC chip and promises clean audio output for a very modest price, but does it impress? 

BUILD QUALITY AND FEATURES OF THE SMSL D6S

The D6s is a really nicely built DAC for the price, it’s housed in a relatively compact package but features a full-size regular IEC cable input for the power supply. The other inputs on the back include optical, coaxial, USB-C, and a port for a Bluetooth antenna, output wise you get a pair of RCA sockets and a pair of XLR sockets – most bases should be covered by these. On the front, you have a display which shows you the sample rate, but also works to help you navigate the menu system. Next to the display is a knob which controls the volume so you can use it as a pre-amp as well as control the menu system. The casing is all black and made from aluminium, it feels rather sturdy and it’s very well finished for its price too, no corners seem to have been cut. 

Feature-wise it can accept all the common high-res files via USB up to DSD512, and DoP64 via Optical/Coaxial – all of these ports also support MQA audio if that’s your thing. Bluetooth is featured on the D6s and supports SBC/AAC/aptX/aptX HD and LDAC, having LDAC on a DAC in this price range is quite impressive and promises to give you excellent audio over Bluetooth for convenience. 

The internal power supply is a low noise switching one to prevent noise from affecting the performance of this DAC. The outputs can output a maximum of 2.5Vrms via RCA and 5Vrms via XLR – this is slightly higher than usual but shouldn’t overwhelm the input stage on most downstream components. In the menu system you can change the digital filter as well as being able to adjust the DPLL bandwidth – this is a huge feature that is missing on a lot of DACs and it can help if you suffer dropouts via optical from devices that have a lot of jitter on their outputs. You can also change the screen brightness, on its lowest setting it’s not too bright or distracting which is good. You also get a remote with the S.M.S.L D6s, allowing you to use it as a DAC/Pre-amp into some powered speakers or a power amp should you wish, the remote lets you change input, control the volume, and change any of the settings in the menu from the comfort of your sofa. 

This DAC is super easy to set up and with my PC no drivers are needed, and with the rest of the ports it is essentially plug and play – it’s absolutely fuss-free and easy to use. 

SOUND QUALITY

I’ve been using this DAC in my headphone setup for a little while now and use it with the iFi Audio iCAN Phantom as a reference point, and to me, that’s what the D6s is best at, being a reference point. This is a typical delta-sigma DAC that does an impeccable job at converting your 1s and 0s into very clean analogue audio without colouring the sound or changing it at all. 

Now, from a subjective point of view, some might call this kind of device boring or cold, but they provide excellent sound and, in this case, do it for an impressively low price. The D6s is simply fabulous at providing a clean and unaltered sound, it’s a DAC that lets you hear what your downstream kit is doing rather than what it is doing itself. 

Alesana – Pathetic, Ordinary is an energetic track at the best of times and, not one I thought I’d find myself using in a review, but the S.M.S.L D6s delivered such clean audio to the Miltra OTL-8XT valve headphone amp that it really allowed me to appreciate the headphone amp and Beyerdynamic DT880 600Ohm headphones themselves. Now this might sound counter-intuitive, after all, I’m supposed to be reviewing the DAC, however, this is in fact high praise for the D6s getting out of the way. It allows everything else to colour the sound to mine, or your, personal preference. Bass hits with authority and body, but there isn’t any additional warmth, the midrange is crystal clear and the treble has no trouble with extending right up out of audible range. 

Feeding the XLR outputs into the iFi iCAN Phantom and powering the HiFiMAN Susvara it never sounds like it holds them back or takes anything away from the overall sound. The soundstaging is still huge, the midrange beautifully balanced and natural, and the treble smooth and extended. If you want a DAC that just passes the audio through, warts and all, the D6s is excellent at this. It might seem odd to pair a sub £200 DAC with an amp and headphone pairing costing over £9k, but the D6s does not disappoint and I strongly believe that if you hid the D6s out of view nobody would complain, or think the DAC feeding this combo was the weak link.

My favourite song by The Appleseed Cast came on, it’s called A Dream for Us, and the recording has a lovely sense of space to it with soft guitars that are panned hard left/right within the mix. The D6s does a superb job of portraying this mix without getting in the way of the song, the snare drum is taut and snappy, allowing you to hear every strike of the drumstick, and the vocals are set back ever so slightly on purpose to give the instruments focus. Cymbals shimmer and fade off effortlessly and the whole soundscape is captivating, leaving me in aural heaven. 

This DAC lets the downstream components do the heavy lifting and it’s not a DAC you would buy to give colour to your existing system, it is one that you would get for it to get out of the way of the music in an unobtrusive manner. This is a DAC that has a tight grip on the music and never sounds slow or congested, it’s always clean and tight and delivers music in a very linear manner. It’s the perfect discreet DAC that can be left in a system without drawing attention to itself. 

Bluetooth works very well on the D6s, yes, there is always going to be a slight drop in quality due to the lossy nature of the compression, but using it with a Pixel phone using LDAC it really is very detailed. Bluetooth is always more of a convenience feature but, S.M.S.L didn’t skimp on the formats and offers up very respectable Bluetooth quality.

QUIBBLES

I guess the one quibble I might have is the display on the front sits proud by a couple of mm, meaning it’s difficult to stack another device on top of this DAC. 

CONCLUSION

The S.M.S.L D6s is a truly excellent DAC for its price, with an audibly linear and transparent sound, it aims to leave any colouration to the equipment downstream. I know linear delta-sigma DACs are not everyone’s cup of tea, but this is a very well-designed and well-implemented ESS-based design that is flawless at what it does. 

The balanced outputs are a good inclusion for the price and it is flexible in terms of inputs with coaxial, optical, USB and Bluetooth available. The ability to control the volume also means you get a pre-amp function for use with powered speakers and the remote facilitates this. 

Having a DAC like this around also helps set a reference point too, knowing that it isn’t adding or taking anything away from the sound allows you to set a base point for comparisons.

AT A GLANCE

Build Quality And Features:

Solid metal

Good quality connectors

Easy-to-read screen

Sound Quality:

Linear and detailed

Value For Money:

Excellent value for money, cheap yet audibly transparent and well-built

We Loved:

Ease of use, it is a plug-and-play DAC

Reference sound quality without colouration

We Didn’t Love So Much:

I can’t pick any faults with this DAC, it does what it’s supposed to do without any quirks

Elevator Pitch Review: If you want a clean and linear DAC that has multiple inputs and balanced output the D6s really is very hard to beat for such a low price. Its aim is to not add anything to the sound, instead it lets the downstream components shine. It’s a fit-and-forget DAC that gets on with the job at hand without drawing any attention to itself, yet has great features allowing it to fit into most systems without issue.

Price: £179/$199/€179

Oscar Stewart

SUPPLIED BY APOS AUDIO

SUPPLIED SPECIFICATION

• 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)