SMSL SU-6 DAC and SH-6 Headphone Amplifier/Preamp Review (1) – Bargain…
SMSL SU-6 and SMSL SH-6: One can’t help but be impressed by the build quality and the feature set packed into this sub-$300 duo—bluetooth, preamp functionality, remote volume control and input switching, adjustable digital filters, gain settings, etc.
Granted, there’s some evidence of cost cutting—no balanced outs, and the front panel switches and volume knob on the headphone amp seem a bit flimsy, but work as intended. Little of this would, of course, matter unless the SU-6/SH-6 sounded good, but fortunately they do.
As a headphone amp, the SH-6 isn’t a powerhouse (it hits its limits with my 250 ohm Beyers), but immediately impresses with its low end impact and control—slightly boomy IEMs like the Moondrop Kanas Pro sound tighter, while more balanced pieces like the Whizzer Kylin HE03D or the 7Hz Timeless show palpably more low end depth and presence.
Other than juicing up the bass, the SH-6 is quite neutral in tone—neither bright nor warm–and added very little coloration across the spectrum. Compared to my trusty (tube) Aune T1 MK2, the SH-6 played louder, had the more expansive soundstage and presented a lot more high end detail; the Aune had the more analog, organic timbre, with the SH-6 sounding a bit leaner and more processed, albeit more resolving.
My ($150) Project Head Box S2 actually was a close match tonally for the SH-6, with a comparable level of high-end detail, but lacked the bass thwack and speed of the SH-6.
Moving to the headphone section of the pricier Chord Mojo gets you a richer, fuller-bodied sound, with noticeably better loud/soft dynamics and a wider stage. However I actually thought the bass on the SH-6 was crisper and extended deeper than the Mojo’s, which sounded smoother and not as sculpted.
The SH-6 likewise functions very serviceably as a digital preamp, again maintaining its neutral tone and tight bottom end, although careful pairing with sources/speakers is necessary, as the SH-6, in high-gain mode, can get a tad shrill with higher output devices or very sensitive speakers.
The SU-6 DAC was initially the more intriguing of the pair, largely because of its lineage from the genuinely great ($450) SU-9, with which it shares a variant of the ES9038 chip. While I usually avoid measurements and graphs (which often skew my impressions on how a piece actually sounds), I cheated on this one and checked out Audioscience Review, which showed extremely good measured performance, including very high SINAD. In fact, the SU-6 was dead quiet, with no audible distortion.
As a standalone DAC (decoupled from the SH-6), the SU-6 sounded slightly bright, with a taut note texture and mostly balanced throughout the spectrum, with an etched, slightly sharp-sounding high end which can sound a little intense on amplified instruments (note that the adjustable digital filters have a small but audible effect on mitigating the intensity).
Microdetails are very present (you can clearly hear the difference between 32/768 files and lower rez stuff), though Bluetooth streaming sounded like typical Bluetooth—compressed and somewhat rolled off at the high end.
Paired with the SH-6, the SU-6 takes on the bassy-but-not-bloated character of the amp, while retaining its slight harshness at the highest frequencies. It’s a good combo nonetheless, with a high level of resolution and good PRAT. The 3x pricier SH-9/SU-9 combo, at least from memory, is more powerful and refined at the high-end, though the qualitative differences are incremental.
Most of the other reviews I’ve read have labelled the SH-6/SU-6 a good “beginner setup”, and like anything else you can certainly spend more and get better. Frankly, unless you’re driving 600 oHm planars I wouldn’t feel a lot of compulsion to upgrade from this little stack—it does many things well and its bass quality trumps a lot of pricier pieces. Bargain.
Disclaimer
This stack was sent to me by SHENZHENAUDIO for review purposes and I thank them for that. It will go to Durwood for a 2nd opinion.
SMSL SU-6 DAC: tested at $169.99. Get it from SHENZHENAUDIO.
SMSL SH-6 amp: tested a $119.99. Get it from SHENZHENAUDIO.
