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Measurements Of Generic ES9038Q2M DAC Board

March Audio

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#1
This is part 2 of my selection of Chinese delights. Again bought from Audiophonics to avoid delivery delays, this board can be found from multiple Ebay vendors for $30 - $40 US.

https://www.audiophonics.fr/en/diy-...alanced-dsd-1x-lt1963-regulators-p-12557.html

Based on the ESS ES9038Q2M chip it is one of the latest chips out, this version being the cut down low power version of their flagship 9038.

IMG_20180303_112854.jpg


The board is interesting because of the potential for a very easy DIY build of what should be a competent DAC. You have 2 choices for power:-
  • 15 V DC through a barrel connector
  • + - 15 vDC through a 3 pin connector
So you could just plug in a wall wart PSU and away you go. This is what I first tried but 50Hz mains did leak into the dac output. Not at a huge level about -120dbFS, but nonetheless it spurred me to try the +- 15V supply. To do this you have to remove 3 zero ohm SMD links. Plugged it into my lab PSU and the mains components disappeared. Its possible that a different wall wart would not have the mains leakage issue. I performed all tests with +- 15 v supply.

The board has electrical and optical SPDIF and i2s inputs. The active input is selected via jumpers. The board also interestingly has image filter option again jumper selected. I used an XMOS based USB to i2s board for input. Note this board does have a 100MHz clock so doesnt require clock from the i2s input. IIRC I used fast roll off linear filter.

You can also connect a pot to the board to act as a digital volume control.

upload_2018-3-3_11-52-52.png


The board appears to use the DAC in voltage output mode with a dual 5532 op amp as the output device for single ended and headphone connections.

Measurements

0dBFS - Output is 2.33 Vrms. Disappointingly high 2 and 3rd harmonic distortion
upload_2018-3-3_12-3-53.png


-6dBFS
upload_2018-3-3_12-5-42.png


-60dBFS
upload_2018-3-3_12-10-14.png


-90.31dBFS 24 bit Waveform - Fairly clean
upload_2018-3-3_12-11-52.png


J-Test - No Significant jitter
upload_2018-3-3_12-15-18.png


IMD SMPTE - Fairly clean in terms of number of harmonics and sidebands but at high level. Commensurate with the related HD.
upload_2018-3-3_12-16-20.png

upload_2018-3-3_12-17-39.png


FR and Imaging
upload_2018-3-3_12-20-16.png


Noise Floor - Quiet :)
upload_2018-3-3_12-43-9.png


Linearity - Excellent
upload_2018-3-3_12-41-32.png


Conclusions? If it wasnt for that high harmonic distortion this would be a really interesting board. Cheap as chips, plenty of features and easy option to make a DIY DAC.

How does it sound? Again into my Oppo PM1s it doesnt quite have the clarity of my Chord Mojo but I could seriously live with it. I know the audiophiles will say I'm deaf, but its really not bad at all ! :eek:

Maybe with some circuit finessing the HD can be brought down. I will try a bit of op amp rolling to see what effects that has (probably instability and oscillation :) )
 
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Jimster480

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#2
Pretty cool test!
I would love to have time to mess around with these! But alas I am very busy so I think I'm okay just purchasing Topping stuff for now.
 

RayDunzl

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#3

dc655321

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#4
0.001 THD = -60dB, maybe corresponds to your "disappointing" measurement...
The plot indicates THD in percentage.
0.001% = 0.00001 = -100dB @ 2V

Or, am I arithmetically challenged? Wouldn't be the first time...
 

RayDunzl

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#5
My mistake.

Thank you.
 
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Krunok

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#6
The plot indicates THD in percentage.
0.001% = 0.00001 = -100dB @ 2V

Or, am I arithmetically challenged? Wouldn't be the first time...
Ray wrote "0.001" which equals 0.1% which again equals -60dB @ 2V. That means Ray was actually right. Or, I'm arithmetically challenged? Wouldn't be the first time for me as well.. :D
 

Krunok

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#8
Oh, I was looking at the wrong graph - not the one Ray posted but the first graph of measurements on top of the page. Somehow I read -60dB there which equals to 0,1% or 0,0001 as Ray wrote. I guess I will have to wait for anther chance to save that gorgeous looking avatar lady. :D
 

Krunok

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#9
Btw, do you guys think that 5532 op-amp is responsible for those relatively high measured distortion?
 
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#10
It could be worth measuring the voltage directly on the DAC's chips analog power supply pins. The PSRR of the DAC chip is poor.
 

babolcs

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#11
The measure is really intersting and valuable.

besides I would mention that, on diyaudio there is a quite intensive thread in the topic of modding of this board.

Even personally me did a lot of changes (change all the L to separated regulators, change the output to I/V stage (47920), add Salas Power supply to analog add a special OPA based regulator to AVCC (own design) change OPA to 47920, change caps to ELNA, added upsample modul, etc... .
And the final sound is really uncomparable to the first one.. (I can't exactly judge, but now it is somewhere in the range of a 500$-1000$ DAC.)
It is really enjoyable to listen now.

IMG_1296.JPG

And I have to tell even there are other guys who even did more (change to clock to decrease the jitter, etc...)
 

Krunok

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#12
The measure is really intersting and valuable.

.. change OPA to 47920 ..
THD spec of OPA 5532 doesn't really imply that it is the reason for 0.02% of THD.

Not that 0.02% presents any real hearable issue, but it would still be interesting to know what is the main cause for such relatively high THD.
 

andreasmaaan

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#13
THD spec of OPA 5532 doesn't really imply that it is the reason for 0.02% of THD.

Not that 0.02% presents any real hearable issue, but it would still be interesting to know what is the main cause for such relatively high THD.
Especially not given that it's basically all H2 and H3. Could even be a quite pleasant addition, to the extent it is audible.
 

maxxevv

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#14
I can assure you the bulk of the sonic characteristics you can hear are actually from the opamp chip swaps.

I have swapped between the NJC5534, AD797 and LT1128 on my portable E19 DAC Amp. You don't even need to 'try' to pick out the differences...
 

Krunok

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#15
I can assure you the bulk of the sonic characteristics you can hear are actually from the opamp chip swaps.

I have swapped between the NJC5534, AD797 and LT1128 on my portable E19 DAC Amp. You don't even need to 'try' to pick out the differences...
The only problem with that is I'm not able to find any properly conducted blind test where somebody managed to hear the difference between op amps. Do you know of one?

I'm also wondering how difficult must be for you to choose an amplifier or even worse, the loudspeakers. I mean, if you can hear the op amp THD in the range of 0.000X % than THD of amp which is typically 0.0X % or that of loudspeakers which is 0.X % must really sound hursh and distorted to you.
 
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andreasmaaan

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#16
The only problem with that is I'm not able to find any properly conducted blind test where somebody managed to hear the difference between op amps. Do you know of one?

I'm also wondering how difficult must be for you to choose an amplifier or even worse, the loudspeakers. I mean, if you can hear the op amp THD in the range of 0.000X % than THD of amp which is typically 0.0X % or that of loudspeakers which is 0.X % must really sound hursh and distorted to you.
Not exactly what you're after, but close: Subjective and Objective Evaluation of Distortion in Analogue Electronics
 

amirm

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Krunok

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