S.M.S.L SU-6/SH-6 DAC/amp combo

The Topping EX5 is my current go to desktop DAC/amp for under $400 and after hearing about the SU/SH-6 prior to release I was excited to see how the stack performed at it’s lower price tag. The pictures I received in advance made the device look like it might be smaller than the normal DAC/amps I usually review. I was quite surprised upon receiving both units and seeing their size in person. The SU-6 is using a ESS ES9038Q2M DAC. The SU-6 comes in at $169.99 and the SH-6 costs $119.99. The combo can be picked up with an included RCA cable set for $289.98.


Thanks to Shenzhen Audio for hooking me up with both review units. While I always appreciate stuff being sent in to test and review, It never affects the rating of my review.


The SU-6 can be picked up from Shenzhenaudio below
https://www.shenzhenaudio.com/produ...cm768khz-32bit-bluetooth-5-0-ldac-usb-decoder

The SH-6 can also be picked up below
https://shenzhenaudio.com/products/...input-6-35mm-mini-desktop-headphone-amplifier

Combo with RCA can be grabbed here
https://shenzhenaudio.com/products/smsl-su6-dac-sh6-headphone-amp-rca-cable-combo

Gear used​

S.M.S.L. SU/SH-8S, Lotto PAW S1, Moondrop Blessing 2, THIEAUDIO Clairvoyance, Moondrop Variations, Dethonray Tender 1, Sennheiser HD560S.

Looks and Feel​

The stack is small and my first thought was ”This is so adorable!”. I’m used to bigger stacks or smaller portable DAC/amps so this was a nice and fresh set of units to get. The finish is a nice smooth matte color and with low glare on both the silver and black. The little LED on the SH-6 has adjustable brightness which was a nice surprise and the SU-6 display was simple but I liked the white LED display. The big thing here is the size though and I already set it up next to my bed at night since I don’t have much space on my nightstand.

Accessories and unboxing​

We get power cables for both devices and the SU-6 box comes with a USB-C cable, antenna and remote. The SH-6 just has the power cable. RCA cables would need to be either purchased separately. Right now(time of review) if you buy the combo stack via Shenzhenaudio, they include a basic RCA cable.

Power switch and volume knob​

Much like the recent Topping E50 I reviewed, The SU-6 has a touch sensitive button for turning on and off the device, as well as changing inputs. You can also use the remote to handle the same things. The SH-6 has clicky toggle switches which I always enjoy using. The SH-6 has an off, headphone amp only or pre out on one switch and the second switch is to go from low to high gain. Volume knob looks a little cheap but it feels fine and is smooth to rotate. I added a bronze dot to the volume indent via a sharpie so I could see the volume location without getting close to look.

Sound(overall)​

These final impressions were done off the SH-6 attached to the SU-6 via RCA. This will be what the SU/SH-6 sounded like with all the headphones I used. Things like headphone pairings will produce different results and impressions vs what my ears hear on my specific gear.


The little SU/SH-6 stack has fairly good hits down low for such a cheap stack. I was surprised that I heard some bass on the stack when I first listened and it was a sticking point by the time my testing was done. While I was really surprised by the low end energy since I don’t get much bass on cheaper amps, I wouldn't say it's better nor quite as good as DAC/amp stacks in the $500 plus range. The bass does have a better impact on a lot of headphones I tested with. This is gonna be the main highlight as I found the mids to be fairly average and the highs feel the same way and almost too dry at times. The mids and vocals overall have ok detail and I can’t say I was disappointed but the main thing I tested this against was the EX5 from Topping and I found that to have better mids. The treble pulls in details alright but I always felt like the treble was a little too clean and almost lifeless for my tastes. It’s not a bad treble, I just get old school THX treble soulless vibes and I don’t like it personally. Still an impressive stack though from my testing.

Imaging/Soundstage​

I usually say staging and Imaging are more headphone dependent. This is very much the case here. Nothing crazy happened when I plugged in headphones that scale well with more powerful gear. I would have preferred this combo had its own little flavor in terms of soundstage but it’s honestly fine for the price.

Inputs and outputs​

We have some pretty straight forward inputs and outputs. On the SU-6 DAC we have an USB-C input, optical input and coaxial input. We have a single set of RCA outs. On the SH-6 we get the single RCA input, a RCA pre out and a ground lug, not sure what the ground lug is for and the user guide just claims it's a ground lug. I had planned to ground my turntable to see if I could make use of the ground but forgot to test this by the time I finished the review. This is all pretty simple when it comes to inputs and outputs and it’s fine since it’s not meant to be a balanced stack.

Personal grips with the SU/SH-6​

I don’t have any big complaints with the SU/SH-6 stack. I like the SU-6 display and new remote. The SH-6 has a single LED that was bright when I first used it but the manual tells you how to adjust its brightness which made that complaint go away. So good job to the little S.M.S.L stack for not irritating me haha

Single ended power output​

We get an average(by modern standards) 1.3 watts into 32 ohm which is ok but I would have liked to see 2 watts personally. I’m mostly an IEM person these days so big power isn’t super needed but those looking to power hungry headphones might want to take note. I got no hissing on any of my sensitive IEMs and I was pretty much good to go on all the headphones I tried when it comes to the min and max volume range on each gain.

IEM pairing opinions​

Moondrop Aria​

I love the Aria since it does good at every music genre for only $70. I wanted to pair the S.M.S.L stack with the Aria to see how they sounded together. The Aria maintains its wonderful “all rounder” sound with a nice balance overall. I didn’t notice any benefits using the entry level S.M.S.L stack with the aria compared to something like iFi’s hip dac but the Aria doesn’t really scale IMO with more expensive source gear. This is a perfectly fine pairing.

Moondrop Variations​

The Variations do scale a little when paired with better gear and while the listening experience here was perfectly acceptable. The lows still maintain a nice thump and stay dynamic without getting bloated, the mids continue to be average without fatigue and the added treble sharpness gives a decently perceived detail retrieval. Still a bit on the edge of my comfort for long listening. I’ve had the variations treble pull better detail retrieval with less intense lower treble on better gear but I didn’t mind this pairing at all.

Over ear pairings​

Sennheiser HD560S​

The 560S is a great mid focused headphone for those starting out on full size cans. I mean almost all Sennheiser headphones, 6XX and under tend to be great starter headphones. I personally don’t care for the mid-focused 560S but I still test gear with it and I found the pairing with the little S.M.S.L stack wonderful. The 560S sounded a little better at the low end frequencies. It still had no impact but the subbass did reach further down than something like the iFi GO blu or apple dongle. Mids stayed smooth and accurate with nice vocal presence. The treble benefited from the ESS sharpness and sounded just a little bit more accurate but with a slight hit to the airiness I get from a more powerful amp. I think this stack would do great for something like the 560S or possibly Senn’s other headphones.

Meze Elite​

I have the $4k Elite in for review so why not pair the combo. The Elite is a full size can that doesn’t need much power to sound good. I can run it off pretty much anything and get an enjoyable experience. It does scale better with more powerful gear but it doesn’t need much to sound good. The SU/SH-6 stack does well with handling the Bass and lower mids. Things sound clean and accurate. The treble is where things start to fall off however. There is a noticeable hollow sound in the upper mids to all the treble. A light hint of tinny sound as well. This is probably a limitation of the SH-6 amp and it’s smaller power supply. You could in theory get away with this pairing but I’d personally would get something mid range DAC/amp wise for the elite at minimum.

DAC/Amp comparison​

Topping X Shenzhenaudio EX5​

The EX5 is my recommended DAC/amp under $400 so I wanted to see how they compared. The EX5 gets an 4 pin XLR headphone jack and the option for XLR pre outs on the back of the unit. The EX5 costs an additional $60 so is there any big difference? No, not really! Both use an ES9038Q2m DAC and both output 1.3 Watts into headphones at 32 ohm. The only real difference I could tell was that the S.M.S.L stack came in with a harder hitting bass but the EX5 had a warmer and more enjoyable treble. The differences are small and without having both to A/B test, you would never know. It will come down to whether or not you want XLR pre outs. The front XLR headphone jack on the EX5 doesn’t provide any extra power so it’s more than likely single ended vs truly balanced. If you need the smallest device in terms of width and depth then the SU/SH-6 stack is the winner. The S.M.S.L stack is a little taller than the EX5.

Overall thoughts​

I like the way the S.M.S.L SU/SH-6 stack looks and it does its job pretty well for the price. I have no complaints and for a beginner DAC/amp stack I would easily recommend this for those getting into the hobby. The EX5 collab from Shenzhenaudio is also a good option and both products will be my go to recommendation for new audiophiles. Good job as usual to S.M.S.L for making another good stack at a great price! Thanks for reading!