• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

SMSL D-6s Balanced DAC Review

Rate this DAC:

  • 1. Poor (headless panther)

    Votes: 9 2.4%
  • 2. Not terrible (postman panther)

    Votes: 5 1.3%
  • 3. Fine (happy panther)

    Votes: 25 6.7%
  • 4. Great (golfing panther)

    Votes: 334 89.5%

  • Total voters
    373

nanook

Active Member
Joined
Mar 31, 2019
Messages
101
Likes
91
Location
Berlin, Germany
The Topping E50 e.g. allows to use the RCA and TRS connection alternatively or in parallel.
For the SMSL D-6s I never came across such a selection in the menu and as far as I remember I did not switch anything and I measured both RCA and XLR outputs when checking the unit upon delivery.
-> 99% confidence that both outputs work in parallel
 

danielpugh

Member
Joined
Jul 11, 2020
Messages
12
Likes
5
@nanook brilliant - I'm pretty sure, but nervous during the return period. Very tempted by e70 for certainty because of the setting in the menu, and the 12v trigger.

However I love/very happy with this DAC (tested d10s, and e50). E50 was also good, but stopped working randomly after a week (not detected on usb). Whereas have a good feeling for this one..
 

nanook

Active Member
Joined
Mar 31, 2019
Messages
101
Likes
91
Location
Berlin, Germany
E50 was also good, but stopped working randomly after a week (not detected on usb).
This sounds interesting. The E50 I have on loan from a friend has the same fault on the USB (not detected) and it seems to be picky regarding jitter on Toslink and SPDIF (intermittent crackling noise).
I'm using the default setting (I think it is "4") for the jitter tolerance DPLL on the D-6s and it plays without problems with the same Toslink and SPDIF sources.
 

danielpugh

Member
Joined
Jul 11, 2020
Messages
12
Likes
5
This sounds interesting. The E50 I have on loan from a friend has the same fault on the USB (not detected) and it seems to be picky regarding jitter on Toslink and SPDIF (intermittent crackling noise).
I'm using the default setting (I think it is "4") for the jitter tolerance DPLL on the D-6s and it plays without problems with the same Toslink and SPDIF sources.
Yep was super strange. RCA out to Wiim amp at the time, and power from a Samsung mobile adapter. At roughly the same time the amp reset itself to defaults, so maybe a power surge of some sort, but afterwards everything was fine just no detection in windows.

Slightly more reassuring that the d6s has a power supply I guess..
 

Stephen

Member
Joined
Feb 25, 2020
Messages
97
Likes
136
I have received my 2nd D-6s this week (the DAC in the other room started to break down and simply was not worth getting repaired).
The D-6s is hooked to a small NUC Windows-PC (->USB), to a LS-Teufel streaming device (->Toslink) and to a Samsung DVBT2 TV-receiver via a small HAMA Toslink-SPDIF converter (->coax).
With the default DPLL setting (4) all sources play with no problem. I have not tried to decrease the value yet. Seems ESS has done a very good job designing the DPLL.

It's a nice feature that the D-6s memorizes all settings when the power is cycled; i.e. when it got switched of and on again, signal source, volume setting, etc. are in the same state like before. The unit even memorizes the power state. When you cycled power with the D-6s "on", it will be "on" when you reconnect power.
Hi Nanook, Thank you for these important informations. But can we totally switch off the blue screen? and Can we bypass the volume? thank you in advance.
 

nanook

Active Member
Joined
Mar 31, 2019
Messages
101
Likes
91
Location
Berlin, Germany
But can we totally switch off the blue screen? and Can we bypass the volume?
Display:
Mentioned in post #471: Hold down FN- Key for a few seconds -> off ; Hold down FN-Key again -> on

Volume:
Since it is a digital volume control, it makes no difference if you set it to max (99) or if there would be a bypass. The signal path is identical as far as I understood, there is no real bypassing of circuit stages like we were used to from analog equipment.
Since the unit remembers the settings when power is removed, you have to set it just once and can forget it then.
I would set it to e.g. 93 (about 3dB below full-scale) and you do cover most intersample-overs in case you're doing sample rate conversion somewhere upstream. And this DAC is so quiet that you can easily spend 1 or 2 bits.
Reducing volume in the DAC-chip (the digital volume control the D-6s offers) is far better than reducing the volume upstream - especially when using 16 bit depth only. There was a nice paper from ESS about this topic (see post #398).

Edit: Corrected the numbers and statement above: Vol = 93 --> 3dB headroom, corresponds to 0.5 bits loss in S/N
"The volume from 99 to 0 is not in dB. But between 99 and 30 each time you decrease by 10 digits you decrease the output by exactly 5dB, or if you prefer 1 digit is 0.5dB."
 
Last edited:

nanook

Active Member
Joined
Mar 31, 2019
Messages
101
Likes
91
Location
Berlin, Germany
B.t.w: Has anyone looked at the tolerance regarding intersample overs for the D-6s (or maybe even more general the ES9039)?
AKM chips used to have 2dB headroom as far as I remember and Benchmark built the headroom into their digital datapath.
Since this gives slightly worse numbers regarding S/N @ full-scale, I'm afraid having headroom is not so common.
 

Feesh

Member
Joined
Feb 15, 2021
Messages
37
Likes
10
Location
Berlin
I am getting an audible "pop" from my speakers when the DAC switches sampling rates. Anyone else encountered the same problem?

Most prominent streaming from a WiiM Mini via toslink. Happens less often via USB - PC but it's still there. Getting a 2nd unit to test soon...

You can see the DAC screen going "blank" (losing connection) when switching let's say from 48khz to 96khz on toslink, that's when the pop occurs. On USB-PC it manages to go directly from one sampling rate to another without the "blank" screen in between most of the time - that's also when the pop is absent.
 

Feesh

Member
Joined
Feb 15, 2021
Messages
37
Likes
10
Location
Berlin
Have someone bought this dac yet - any issues with crackling sound when switching between spdif and USB input , or other issues ?

It would be nice to know that the serie version of this dac is as good as the one sent to Amirm.
Quite silent but annoying "static pop" everytime the DAC switches sample rates - WiiM Mini via toslink. Ordered a 2nd unit to see if it's present there.
 

nanook

Active Member
Joined
Mar 31, 2019
Messages
101
Likes
91
Location
Berlin, Germany
Quite silent but annoying "static pop" everytime the DAC switches sample rates
I'm currently using the D-6s from the laptop via Bluetooth (LDAC with alternative A2DP driver for w10). When I change the sample-rate in the Resampler in foobar, there is a small pause, but no pop. I'm using the RCA output of the DAC.

I do most of the attenuation with the volume control of the amplifier however and usually just a couple of dB attenuation with the digital volume control of the DAC (or the volume control in foobar, which is fine if you use 24 or 32 bit depth for the output). I do not want to degrade S/N significantly this is why I wouldn't attenuate say 30dB or more on the digital signal side.
In case you do most of the attenuation with the volume control of the D-6s with the main amp "wide open", I could imagine, that the internal muting circuit of the D-6s also mutes of a small DC component that might be present on the output of DAC filter. This could result in a small "pop".

On my D-6s I do however not observe a "pop" (even with the amplifier on max. volume) when I force the DAC to mute the signal path because I select a different input source.

- Do you use the XLR or the RCA output ?
- Do you observe a "pop" as well when you select a different input of the D-6s?
 

Feesh

Member
Joined
Feb 15, 2021
Messages
37
Likes
10
Location
Berlin
I'm currently using the D-6s from the laptop via Bluetooth (LDAC with alternative A2DP driver for w10). When I change the sample-rate in the Resampler in foobar, there is a small pause, but no pop. I'm using the RCA output of the DAC.

I do most of the attenuation with the volume control of the amplifier however and usually just a couple of dB attenuation with the digital volume control of the DAC (or the volume control in foobar, which is fine if you use 24 or 32 bit depth for the output). I do not want to degrade S/N significantly this is why I wouldn't attenuate say 30dB or more on the digital signal side.
In case you do most of the attenuation with the volume control of the D-6s with the main amp "wide open", I could imagine, that the internal muting circuit of the D-6s also mutes of a small DC component that might be present on the output of DAC filter. This could result in a small "pop".

On my D-6s I do however not observe a "pop" (even with the amplifier on max. volume) when I force the DAC to mute the signal path because I select a different input source.

- Do you use the XLR or the RCA output ?
- Do you observe a "pop" as well when you select a different input of the D-6s?
Tried both XLR and RCA - both pop.

Just got the 2nd unit, also has the exact same pop. The pop can occur anytime the display switches to (---), which happens mostly during bitrate switching - it happens 80% of the time. Locking bitrate to 44khz the pop obviously vanishes.

Using Tidal via my PC over USB eliminates the pop completely on the 2nd unit.

Will test using a new optical cable and WiiM Pro... hopefully that combination works better.
 

nanook

Active Member
Joined
Mar 31, 2019
Messages
101
Likes
91
Location
Berlin, Germany
I have a different setup, where I can check sample rate changes via Toslink. I'll be coming back.

What kind of amplifier (or active speakers) do you have connected?
I suspect the D-6s mutes the output whenever something nasty might occur. Sample rate changes could corrupt data and cause nasty noises.
The D-6s is pretty well behaved regarding the muting functionality - no "pops" at power-up or power-down etc. I had not a single "pop" while using the unit.

This brings to another question: Have you tried a different amplifier?

It's not really likely, but there is a possible scenario that might make "pops" while muting or un-muting:
The muting in the D-6s will be implemented between the output-stage and the XLR and RCA connectors. It is likely that the output resistance of the D-6s is different in the muted vs. the un-muted state. In case the amplifier input is DC-coupled and steers some current out of its input (and thus into the output of the D-6s), a change in output resistance would cause a voltage step at the input of the amplifier and this would be audible.
 

Feesh

Member
Joined
Feb 15, 2021
Messages
37
Likes
10
Location
Berlin
I have a different setup, where I can check sample rate changes via Toslink. I'll be coming back.

What kind of amplifier (or active speakers) do you have connected?
I suspect the D-6s mutes the output whenever something nasty might occur. Sample rate changes could corrupt data and cause nasty noises.
The D-6s is pretty well behaved regarding the muting functionality - no "pops" at power-up or power-down etc. I had not a single "pop" while using the unit.

This brings to another question: Have you tried a different amplifier?

It's not really likely, but there is a possible scenario that might make "pops" while muting or un-muting:
The muting in the D-6s will be implemented between the output-stage and the XLR and RCA connectors. It is likely that the output resistance of the D-6s is different in the muted vs. the un-muted state. In case the amplifier input is DC-coupled and steers some current out of its input (and thus into the output of the D-6s), a change in output resistance would cause a voltage step at the input of the amplifier and this would be audible.

I have an SMSL AO200.

Sadly I do not have an option to try any other amp at the moment.

Will get back to you when I try a different streamer and optical cable combination.
 

danielpugh

Member
Joined
Jul 11, 2020
Messages
12
Likes
5
i have the d-6s (pc-> d6-s ->RCA Output -> WiiM AMP -> speakers & sub), and noticed a few very quiet clicks as i was working, but no pops across about 6hrs.

i did have a different problem which ill detail as i managed to get everything working well so may be useful to others.

problem was no sound on reboot - symptoms were the device having an error in the device manager in windows 11.
Only occurred when using the downloaded driver (XMOS USB DAC Driver).
if i didnt have the downloaded driver windows would identify the device as a headphone DAC, and an exlamation device in device manager, but worked fine.
bodge workaround was to unplug and reconnect the usb cable, but obviously annoying as having to do this after every suspend/reboot
Actual fix:
To connect the cable to the blue USB port (not red) at the rear of the MSI motherboard.

in parallel i was able to confirm full MQA support via roon (logo appears on the DAC).
to do this I had to enable the specific device in roon (as opposed to the default windows device)
then when selected as the output device enter its settings and could enable DSD over PCM v1.0 (DoP), and MQA capabilities (Decoder and Renderer).
the only downside is that roon grabs control of the device so volume wouldnt work on windows itself, and other apps (e.g. MS teams) could not play any sound.
using the default device enabled these features (but obviously blocked MQA etc.

hope that saves someone some time!
 

nanook

Active Member
Joined
Mar 31, 2019
Messages
101
Likes
91
Location
Berlin, Germany
I have a different setup, where I can check sample rate changes via Toslink. I'll be coming back.
I just tried sample-rate changes via Toslink.
Setup was: RWE (ASIO) @800Hz, -80dBFS -> RME Fireface UC -> Toslink -> SMSL d-6s
I did observe sometimes clicks when changing the sample rate in REW. They were about as loud as the sinewave @ -80dBFS and the amplifier was cranked up to max.
No "pops" however. The D-6s displayed the new samplerate immediately without displaying "---" in between.

Sometimes the D-6s did not recognize the 44.1kS/s (and more rare the multiples of 44.1); sounds distorted then. 48kS/s and multiples were always fine. Still no "pops".
 

Feesh

Member
Joined
Feb 15, 2021
Messages
37
Likes
10
Location
Berlin
I just tried sample-rate changes via Toslink.
Setup was: RWE (ASIO) @800Hz, -80dBFS -> RME Fireface UC -> Toslink -> SMSL d-6s
I did observe sometimes clicks when changing the sample rate in REW. They were about as loud as the sinewave @ -80dBFS and the amplifier was cranked up to max.
No "pops" however. The D-6s displayed the new samplerate immediately without displaying "---" in between.

Sometimes the D-6s did not recognize the 44.1kS/s (and more rare the multiples of 44.1); sounds distorted then. 48kS/s and multiples were always fine. Still no "pops".

Thank you very much for your help!

Both models i received had the same ''pop''. Which leads me to believe that the main problem lies elsewhere like you've stated.

Tried different Optical/COAX cables, different streamers and both the XLR and RCA outputs.

The ''pop'' would become audible from my sitting position with the amp (SMSL AO200) at 50% volume.

The pop does not happen on my old SMSL Sanskrith 10th MKII.

Will try next with a different amp (a new SMSL AO200 MKII).
 

timiambeing

Member
Joined
Aug 18, 2020
Messages
51
Likes
29
Thank you very much for your help!

Both models i received had the same ''pop''. Which leads me to believe that the main problem lies elsewhere like you've stated.

Tried different Optical/COAX cables, different streamers and both the XLR and RCA outputs.

The ''pop'' would become audible from my sitting position with the amp (SMSL AO200) at 50% volume.

The pop does not happen on my old SMSL Sanskrith 10th MKII.

Will try next with a different amp (a new SMSL AO200 MKII).
I do hope this isn't totally left field and useless, but in a completely unrelated system (Lumin U1 Mini/Pontus DAC/newly built ISCEPower 125ASX2 Amp) I noticed pops in every track change, this was never evident before the ICEPower amp arrived. After trying all manner of things I read an article discussing output and input impedance matching and how my DAC's had a high output (I think?) impedance and when fed into an amp with a also high input impedance could cause pops as the digital signal went into clipping and the amp translated that as audio (bit vague and probably mixing up my electronic metaphors, but I can't find the damn article now, think it was GoldenSound? :rolleyes:).

Anyway, I also noted how very loud the amp was and remembered I had some in line attenuators so I put them in to get a little more movement on the volume control - result was the pops disappeared. No amount of reducing the digital volume (in the Lumin) produced this effect, but an analogue attenuation did the trick... go figure? So it may be how your amp is seeing the DAC clipping as it changes bit rate? Beyond my understanding, but I thought as I had the same problem and attenuation solved it that might be a clue?
 

Stephen

Member
Joined
Feb 25, 2020
Messages
97
Likes
136
I do hope this isn't totally left field and useless, but in a completely unrelated system (Lumin U1 Mini/Pontus DAC/newly built ISCEPower 125ASX2 Amp) I noticed pops in every track change, this was never evident before the ICEPower amp arrived. After trying all manner of things I read an article discussing output and input impedance matching and how my DAC's had a high output (I think?) impedance and when fed into an amp with a also high input impedance could cause pops as the digital signal went into clipping and the amp translated that as audio (bit vague and probably mixing up my electronic metaphors, but I can't find the damn article now, think it was GoldenSound? :rolleyes:).

Anyway, I also noted how very loud the amp was and remembered I had some in line attenuators so I put them in to get a little more movement on the volume control - result was the pops disappeared. No amount of reducing the digital volume (in the Lumin) produced this effect, but an analogue attenuation did the trick... go figure? So it may be how your amp is seeing the DAC clipping as it changes bit rate? Beyond my understanding, but I thought as I had the same problem and attenuation solved it that might be a clue?
My DAC D6-s also give a 'click' when automaticaly switching resolution. It doesn't occur always. I did not note if some frequencies changes are more prone to others, but my previous Soncoz Dac never had any sound when resolution changed. I guess it's a hardware problem. I am still balanced if I keep it or not. Still the Soncoz has also a little problem: I have to witch on at least two times to make it work...
 

timiambeing

Member
Joined
Aug 18, 2020
Messages
51
Likes
29
My DAC D6-s also give a 'click' when automaticaly switching resolution. It doesn't occur always. I did not note if some frequencies changes are more prone to others, but my previous Soncoz Dac never had any sound when resolution changed. I guess it's a hardware problem. I am still balanced if I keep it or not. Still the Soncoz has also a little problem: I have to witch on at least two times to make it work...
I loved my little Soncoz, little square one, sounded amazing for the price! Then I got upgraditis and ended up with a Schit Bifrost 2 which I just upgraded to 64 status… I swear the Soncoz was still better! I’m selling the Schiit and heading back into the fray… hence following this thread! :)
 

Grovkalle

Member
Joined
Jan 27, 2023
Messages
29
Likes
21
Made a test today with my new D6s streaming from Bluesound Node N130 using USB and Tidal. Couldn't get any sound at all if the songs was in the Tidal Max format. The green MQA led lit up on the D6s but no sound. Tidal songs in the non-Max format works. Streaming from my Audiolab 9000N via coax worked but seems to be a problem with USB.
 
Top Bottom