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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

trungdtmc

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I tried this method but I couldn't get underneath the recessed knob with some cloth.
Tried a thin nylon string which I was able to push through the gap and behind the knob but regardless of effort and force, the knob did not move a mil.

--> Anyone else able to remove the knob?

I would love to measure the VDDA at my unit ....
I used the fabric edge of the shirt, because it had folds and was thin enough to slide under the knob.
 

nanook

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I used the fabric edge of the shirt, because it had folds and was thin enough to slide under the knob.
On my unit there's hardly more than 0.5mm gap around the knob and the knob is recessed, so it's almost impossible to get something underneath.
 

trungdtmc

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Did you heat the knob heavily or just a little bit?
I was already guessing it might be glued. I bought this D-6s in late December 2023
Your d-6s has a serial number 3xx smaller than mine. I think the cover, specifically the gap, is the same. Maybe I'll make a short video
 

talev

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Did you heat the knob heavily or just a little bit?
I was already guessing it might be glued. I bought this D-6s in late December 2023
No need to heat heavily. Just enough to soften the glue. Definitely less than a min
 

Palladium

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Does this have implications for the longevity of the DAC?

Enthusiast PC motherboards have long overvolted CPUs by factory default beyond their official max rated specs virtually without any longevity issues, so chances are nah.
 

Dunring

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Enthusiast PC motherboards have long overvolted CPUs by factory default beyond their official max rated specs virtually without any longevity issues, so chances are nah.
Yep, I've overclocked and overvolted stuff for years before things got powerful enough you don't really need to go to extremes anymore. I just got a D-6s today and it sounds great (as in no click when switching bit rates like the DL200 did). Some like Gustard ran the X26 pro with it's twin chips so hot, I saw one used for sale where the coating on the sides had bubbled from the heat but it was still running. I had one and you could literally keep a coffee cup warm sitting on it. They said running the 9038Pro's in current mode sounded better, even the Topping D90MQA was pretty warm compared to this.
A 5 volt DAC for $200 and real XLR outputs, all I need (have several amps designed for 5 volt input). Just wish it was a little wider to put an A30Pro on top of it without looking dorky :)
 

JIW

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Nov 11, 2019
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Volume Control on the D-6s measured at 1kHz and Full-Scale sinewave on XLR outputs
SN: 33212330199

View attachment 351948

View attachment 351949

Edit: I have double-checked several times, the "missing step" is real and it fortunately applies to both channels - nothing to worry about though.

I did some similar testing on my DL200 when I first got it (See quote below). I did some more testing today. My results are in line with yours. In particular, the 88 to 89 step does not change the level.

Curiously, in my original raw measurements, the level difference between 80 and 90 is exactly 4.5 dB instead of the expected 5.0 dB for 10 0.5 dB steps. From 80 to 70, from 70 to 60, from 60 to 50, from 50 to 40 and from 40 to 30 are all exactly 5.0 dB as expected. However, I did not think too much about it and thought it due to measurement uncertainty.

I got mine today and rudimentarily measured the steps in the volume control using headphones, a 1 kHz tone and an SPL meter app on my phone.

The ESS chip can go from 0 dB to -127.5 dB in 0.5 dB steps for each channel (ES9039Q2M datasheet, page 15). The DL200's volume control has only 100 steps from 0 to 99, however. Thus, it may well differ in some way.

Volume 00 is mute. From 99 down to 25 is in 0.5 dB steps, i.e. 25 is -37.0 dB, 50 is -24.5 dB and 75 is -12.0 dB. 20 is 5 dB lower than 25, i.e. 20 is -42.0 dB. Below 20 is unclear but 01 is about 28 dB below 20, i.e. 01 is about -70 dB.

The line output is closest to 2 V RMS RCA and 4 V RMS TRS at volume 95, i.e. -2.0 dB, giving 1.9858 V RMS and 3.9716 V RMS, respectively.

Maybe @SMSL-Mandy can give the exact values.
 

nanook

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Yep, I've overclocked and overvolted stuff for years before things got powerful enough you don't really need to go to extremes anymore. I just got a D-6s today and it sounds great (as in no click when switching bit rates like the DL200 did). Some like Gustard ran the X26 pro with it's twin chips so hot, I saw one used for sale where the coating on the sides had bubbled from the heat but it was still running. I had one and you could literally keep a coffee cup warm sitting on it. They said running the 9038Pro's in current mode sounded better, even the Topping D90MQA was pretty warm compared to this.
A 5 volt DAC for $200 and real XLR outputs, all I need (have several amps designed for 5 volt input). Just wish it was a little wider to put an A30Pro on top of it without looking dorky :)

Well, you cannot say in general if operating a CMOS IC at elevated supply is safe. This depends on how conservative the acceleration factors in the qualification of the process are and on the individual design (especially if it comes to analog circuits, where some transistors spend their whole life in a stressful operating point). It also depends on the target market - chips with automotive qualification e.g. have to fulfill stricter failure rates in longer timeframes.

Temperature is not my real concern - semiconductors operate well at say 85 or 100 degree Celsius - the problems associated with this have long been solved (except for temperature cycling which mechanically stresses package, bonds and solder jounts).

My concern is NBTI and HCI (both of them use the term "hot electron" but this doesn't refer to the device temperature).



Operating a design at the max. ratings is not a good idea in general - this will usually reduce life expectancy, but to what extent only the manufacturer can tell - at best (in the accelerated life testing you stress many ICs and watch out for changes in parameters, particularly specified parameters - if you observe no or only moderate drift the result is "pass" i.e. this design is considered to yield the required life expectancy).
If an IC design is good, the life expectancy under nominal conditions may be even 50 years or more. Not an issue if this drops significantly. But - as I said - this strongly depends on the individual design.
When I worked in IC design (automotive), every single design had to undergo these stress tests before this IC was released for production . If the technology itself is fine, one or the other design can still have devices operated in too aggressive operation points.

All in all I'm not too concerned. My DAC does not at all run 24/7 and this is what the ES9039q2m must have been designed for (professional use).
The ES9039q2m is available, there is a lot of space around the IC and the PCB does not have components fitted on the bottom side, so with heat-plate and hot-air changing the IC should be feasible in case problems show up.
I'm happy to read all other supplies are nominal - a dead XMOS would be more of a problem due to its on-chip flash I guess.

I will give removing the knob another try because I'm still interested, if AVCC ~= 3.70 is indeed typical for this product. If not, this discussion is obsolete anyway.

-> Did anyone else measure AVCC already?
 

trungdtmc

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Well, you cannot say in general if operating a CMOS IC at elevated supply is safe. This depends on how conservative the acceleration factors in the qualification of the process are and on the individual design (especially if it comes to analog circuits, where some transistors spend their whole life in a stressful operating point). It also depends on the target market - chips with automotive qualification e.g. have to fulfill stricter failure rates in longer timeframes.

Temperature is not my real concern - semiconductors operate well at say 85 or 100 degree Celsius - the problems associated with this have long been solved (except for temperature cycling which mechanically stresses package, bonds and solder jounts).

My concern is NBTI and HCI (both of them use the term "hot electron" but this doesn't refer to the device temperature).



Operating a design at the max. ratings is not a good idea in general - this will usually reduce life expectancy, but to what extent only the manufacturer can tell - at best (in the accelerated life testing you stress many ICs and watch out for changes in parameters, particularly specified parameters - if you observe no or only moderate drift the result is "pass" i.e. this design is considered to yield the required life expectancy).
If an IC design is good, the life expectancy under nominal conditions may be even 50 years or more. Not an issue if this drops significantly. But - as I said - this strongly depends on the individual design.
When I worked in IC design (automotive), every single design had to undergo these stress tests before this IC was released for production . If the technology itself is fine, one or the other design can still have devices operated in too aggressive operation points.

All in all I'm not too concerned. My DAC does not at all run 24/7 and this is what the ES9039q2m must have been designed for (professional use).
The ES9039q2m is available, there is a lot of space around the IC and the PCB does not have components fitted on the bottom side, so with heat-plate and hot-air changing the IC should be feasible in case problems show up.
I'm happy to read all other supplies are nominal - a dead XMOS would be more of a problem due to its on-chip flash I guess.

I will give removing the knob another try because I'm still interested, if AVCC ~= 3.70 is indeed typical for this product. If not, this discussion is obsolete anyway.

-> Did anyone else measure AVCC already?
I touched the es9039q2m with my hand while it was operating and found it was not noticeably warm. Maybe 3.7V with AVCC isn't a problem.
In any case, I already have a few es9039q2m chips in my pocket
 

nanook

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Where did you order the ES9039q2m spares?
I might get spares as well - just in case. Eventually I would modify this supply to match the 3.3V +/-5%.
Anyways I will try to get the knob off...

@trungdtmc: You wrote "Yes, I measured the voltage on the 2 AVCC pins near the DAC chip, it is stepped down from the 5V lp2985 through a voltage divider bridge."
This would mean, the voltage at AVCC will eventually depend on the sampling frequency (if they have not upsampled everything to the highest rate anyway). Sampling rate should change the current consumption and thus I*R drop of the voltage divider.

Temperature is not my concern. The electrons resp. holes in the MOS channel reach very high drift velocities such that they can change the characteristics of the MOS transistor permanently (HCI).


I touched the es9039q2m with my hand while it was operating and found it was not noticeably warm. Maybe 3.7V with AVCC isn't a problem.
In any case, I already have a few es9039q2m chips in my pocket
 

trungdtmc

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This would mean, the voltage at AVCC will eventually depend on the sampling frequency (if they have not upsampled everything to the highest rate anyway). Sampling rate should change the current consumption and thus I*R drop of the voltage divider.
Oh, I forgot one thing, that is, the power source from the lp2985, after passing through the voltage divider bridge, will go to the non-invert pin of the opa1612a opamp and from here provide a better AVCC
 

nanook

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Finally I got the knob off. Hot air (ca. 20s, 270°C focused on the knob did work, but I guess a lower Temperature would have done the same (weakening the plastic inside the knob). The plastic basically melted so that I could tear off the metal cap (plastic inset still sitting on the shaft firmly). Then I could get under the plastic inset easily (it is less deep than the metal cap) and carefully lever it up using 2 screwdrivers. Next time I would try something like 80 ... 100 deg Celsius.
I have carefully filed away a tiny bit of the plastic where it sits on the shaft of the rotary encoder otherwise the knob would have been sitting too firm again. Apparently SMSL had an issue with loose knobs some time ago, so this one sits a bit too firm to my taste.
The plastic could be pushed back into the metal cap and sits firmly and the knob should be removable with a firm with the fingers grip now.

Edit: Wrong thought on my side. Same trick as for the ES9038 evaluation board.
There seems to be a contradiction to the old datasheet that I have (Version 0.1.3) regarding the common-mode voltage (Datasheet: Voltage output offset = VCCA/2 ; in reality it seems to be rather 1.25V @ AVCC_DAC = 3.686V which would be ca. 34%).

--> Does someone have a more recent version of the datasheet for me?
Edit: I'd still appreciate a newer datasheet.

Results on AVCC_DAC and extracted schematic of the output-stage will follow.

1709418567853.png
 
Last edited:

trungdtmc

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Finally I got the knob off. Hot air (ca. 20s, 270°C focused on the knob did work, but I guess a lower Temperature would have done the same (weakening the plastic inside the knob). The plastic basically melted so that I could tear off the metal cap (plastic inset still sitting on the shaft firmly). Then I could get under the plastic inset easily (it is less deep than the metal cap) and carefully lever it up using 2 screwdrivers. Next time I would try something like 80 ... 100 deg Celsius.
I have carefully filed away a tiny bit of the plastic where it sits on the shaft of the rotary encoder otherwise the knob would have been sitting too firm again. Apparently SMSL had an issue with loose knobs some time ago, so this one sits a bit too firm to my taste.
The plastic could be pushed back into the metal cap and sits firmly and the knob should be removable with a firm with the fingers grip now.

Edit: Wrong thought on my side. Same trick as for the ES9038 evaluation board.
There seems to be a contradiction to the old datasheet that I have (Version 0.1.3) regarding the common-mode voltage (Datasheet: Voltage output offset = VCCA/2 ; in reality it seems to be rather 1.25V @ AVCC_DAC = 3.686V which would be ca. 34%).

--> Does someone have a more recent version of the datasheet for me?
Edit: I'd still appreciate a newer datasheet.

Results on AVCC_DAC and extracted schematic of the output-stage will follow.

View attachment 353818
I'm sorry you couldn't do it my way, but I think you can find a similar knob on aliexpress or somewhere. The latest document we have is still version 0.1.3. I checked and found that the d-6s still uses the classic I/V circuit, unlike in the ESS documentation.
 

nanook

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I'm sorry you couldn't do it my way, but I think you can find a similar knob on aliexpress or somewhere.
No worries, @trungdtmc , your hint has encouraged me to try what I anyways was thinking might help. And the knob still looks and works perfectly fine, just like before - no need for a new knob.
I just posted the picture so others can see what the innards of this knob are. In fact, if you heat up the whole knob (lower temperature) the "ribs" might get soft too and get deformed when pulling it off.
I'm quite happy with the result - I can remove the knob with my fingers now yet it still sits firmly when pushed on.
 

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gregor

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Jan 25, 2023
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Hello

I would like to upgrade from very old CA DacMagic Azur.

I'm searching for a DAC in 200 to 300 EUR price range. Do you think that D-6S will be a good upgrade, or do you recommend and other DAC in this price range?

One additional question. Till now I did not use XLR cables (I use RCA). Is it a good idea to also buy XLR cables at the same time?

I will probably buy DAC here:


So, I was thinking to also buy XLRs in this online shop:


If you check above link, do you see any good XLRs up to 100 EUR or better less (for pair)? I need cable at least 1m in lenght.

Thank you

Kind regards
 
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