diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Digital Line Level (http://www.diyaudio.com/forums/digital-line-level/)
-   -   Measurements of an ES9023 DAC (http://www.diyaudio.com/forums/digital-line-level/197486-measurements-es9023-dac.html)

fitzfish 28th September 2011 07:06 AM

Measurements of an ES9023 DAC
 
5 Attachment(s)
Several members commented on the quality of audio achievable with an inexpensive DAC chip like the ES9022 or ES9023. I'm impressed with the subjective quality and objective measurements as well.

I started out at 44.1/16 for the measurements and quickly realized that the board is much better than this is capable of demonstrating so 24 bits was the way to go. I also could only find a 24 bit JTEST wav file at 48KHz sample rate so that is what I used. Measurements at 44.1 are for all practical purposes identical…

The analyzer is a UPV from R&S running 256K point FFT with no averaging. The one I have does not include the digital interface option so I use a PC running DR Jordan Designs’ function generator as the source and a Highface USB to SPDIF converter in 48KHZ 24bit using ASIOforall v2. Measurements that used two tones (IMD and DNR) required ASIO to be disabled so they are at 192KHz to make up some of the noise floor lost running without ASIO and driving with two function generator instances.

The first picture is THD at 1KHz and 2V RMS. At a little less than 0.006% it is not earth shattering but very respectable.

The second picture is IMD 18K+20K.

The third picture is DNR at 1KHz with a 10KHz 2V RMS tone. With a noise floor of a microvolt or so RMS the -125 db 1KHz peak is readily visible peeking above the noise. That is ~21 bits of useful resolution. This DAC is dead quiet with a completely black background to the music!

The fourth picture is of the 48/24 JTEST. The -133db peaks are inherent (they are essentially the same with either a single 12KHz tone or with the JTEST signal) and represent jitter of around 3pS. There is almost no measureable increase of data correlated jitter for this board with the Highface.

I notice even low levels of jitter in cymbal ring decay and in the percussive sounds around piano and plucked string instruments. If the cymbals in a good recording sound soft and fuzzy, if the ring decay seems attached to some other sound source, or if the ring decay seems disconnected from the cymbal location it really grates at my preception of the music. The same holds true for the upright bass. Since the fundamental tone and the string plucking/rattling sounds that naturally occur are octaves apart it is a good indicator for my ears. If the string sounds are separate in physical space or out of time from the attack or ring of the note, it really sticks out. The realism of reproduced music for me is strongly tied to how well these attack and decay sounds are placed in the image and in time.

The last picture is of the DAC board itself. I have a final revision I want to make to the PCB to remove some passives and filters I added for testing purposes, as well as to accept different capacitors in the output filter. Other than that it is pretty well finished for now.
:cheers:
Dave

TheShaman 28th September 2011 11:30 PM

Good job! Where do we sign up for these? :)

iancanada 29th September 2011 12:22 AM

Hi Fitzfish,

Interesting job! What is the DIR chip of that dac? Did you try spdif sources with different clock jitter?

Ian

abraxalito 29th September 2011 12:38 AM

Very interesting plots, thanks for sharing. :)

Quote:

Originally Posted by fitzfish (Post 2727090)
I notice even low levels of jitter in cymbal ring decay and in the percussive sounds around piano and plucked string instruments.

How do you know you're hearing jitter on these decays? IME I hear artifacts on some DACs, but its not jitter. Are you saying its jitter because you can't think of what else it might be? If you are hearing jitter when the jitter products are below -100dB that's no mean feat.

Quote:

The last picture is of the DAC board itself.
Looks interesting - may I ask why two transformers, and toroids too? Also is that a mains inlet filter?

EUVL 29th September 2011 04:09 AM

Dave is using WM8804 SPDIF receiver with 12MHz crystal, and 50MHz XO for the ES9023. See here for more details :

http://www.diyaudio.com/forums/digit...ml#post2612326

We have a similar setup with WM8804 and ES9022 (Citizen Xtal with mica load caps), but we have also experimented with 48MHz Crystek XO feeding the ES9022 direct, and at the same time feeding the WM8804 after dividing by 4 using 2 high speed single gate Flip Flops from On Semi. Our experience is that the one-clock-drives-all-approach has much better clarity and details.

There are some differences in our approaches and choices of components, and Dave and I have been discussing AB tests to optimise both our implementations. But I am too busy right now and is hindering his progress. Sorry about that, Dave.

Maybe you should also consider publishing some of your objective and subjective comparisons with the ES9018 evaluation board.

I also recently received feedback from someone who had a balanced 9022 module from me, and he clearly preferred the 9022 to his Buffalo II + various IVs. I have asked if he would also publish his impressions some time.

I am the first to say that I want to build discrete for my own reference system, and the 9022/9023 is not the ultimate DAC available on earth. But when done right, it sounds really damn good, and Dave's different approach has shown that neither of us have really found the optimum of this yet. I sincerely hope that more people will join in to experiment, rather than just copy what we are doing. Only that way can we compare notes and results to discover the remaining potentials of these chip.

;)

One of the test that we plan to do soon is a direct AB comparison between 9022 and 9023, using the same setup.


Patrick

.

fitzfish 29th September 2011 04:35 AM

Quote:

Originally Posted by TheShaman (Post 2728082)
Good job! Where do we sign up for these?


Thanks! No where yet... I am not quite finished and I would really prefer to have some other ears listen to it first. It has also only been connected to two a handful of different systems to audition. I want to hear it in other setups to see if it holds up as well as it has in the limited set so far.

Quote:

Originally Posted by iancanada (Post 2728112)
Interesting job! What is the DIR chip of that dac?
Ian

Thank you. It uses a Wolfsen WM8804 in hardware mode. It directly supports 44.1 to 192KHz with the exception of 176.4KHz. I did not want a micro for ths DAC so it seemed a small price.
Quote:

Originally Posted by iancanada (Post 2728112)
Did you try spdif sources with different clock jitter?
Ian

I tried a TeraLink, Musiland Monitor 01, and the highface USB to SPDIF interfaces for the function generator. These are just what I happen to have. Each had subtle, measureable differences in noise floor(broadband, random jitter), intrinsic jitter spikes (those there all of the time) and how they reacted to JTEST. There were instances where one worked clearly better than the others in a certain mode. I have not listened to any of these other than briefly to the Hiface. All of the DAC listening tests were done with CDs.

Doing an objective measurement comparison that followed with a blind listening test (by more than one person, and excluding the person doing the measurements of course to minimize bias) would make a very interesting read... Someone with a local “audio support group” should take this on!

More in the next post…
Dave

fitzfish 29th September 2011 05:27 AM

Quote:

Originally Posted by abraxalito (Post 2728134)
Very interesting plots, thanks for sharing.

My pleasure.
Quote:

Originally Posted by abraxalito (Post 2728134)
How do you know you're hearing jitter on these decays? IME I hear artifacts on some DACs, but its not jitter. Are you saying its jitter because you can't think of what else it might be?

Good question. I am confident in the conclusion of jitter being the culprit for several of the improvements I made along the way.

It is obviously a subjective measure as I described it, but I was able to back it up with circuit improvements during development that reasonably correlated to measurement improvements. One still baffles me though and I didn't find a correlation in measurements.

I built two boards at each step and always did A/B testing, both subjectively and objectively.
Quote:

Originally Posted by abraxalito (Post 2728134)
If you are hearing jitter when the jitter products are below -100dB that's no mean feat.

Agreed. My conclusions are based largely on the engineering process and on time spent with a formal education in music. Knowing how these instruments really sound in many different settings is kind of a blessing and a curse…

My hearing is pretty good, but I figure I am hearing the differences caused by time inaccuracy and intermoduation effects in the complex music sounds, not by the direct spurious spikes we can see in the simple repetitive sinewave measurements.

The beauty of listening to instruments like the cymbals in my experience is the absolute predictability of the decay if they are allowed to ring naturally. Top hat is great because of its mix of mid and high frequency components. I love that sound in good recordings. Similarly the upright bass fundamental frequencies in the mid range of the instrument are such a long wavelength (yet still directional) compared to the transient of plucking or the rattle of the string when played loudly that it makes any disparity in the timing or placement of these audible cues easier to pick out.

Quote:

Originally Posted by abraxalito (Post 2728134)
Looks interesting - may I ask why two transformers, and toroids too?

Absolutely. My intention was to fit it into a small enclosure to match a headphone/pre amplifier I started some time back. I also was trying to get the lowest possible noise from an AC line supply. The toroids reduce the magnetic induced noise and were easily mounted to the PCB.

The requirement for the second toroid is that I included a JFET follower buffer configured as a second order output filter instead of the RC (the R is internal to the 9023) described in the dataheet. I wanted to be able to drive a pot or other volume control directly... The power supply topology was specifically tailored to get the best performance out of the JFETs I chose and required a seperate supply.
Quote:

Originally Posted by abraxalito (Post 2728134)
Also is that a mains inlet filter?

Yes. It is an off the shelf unit available from Digikey. I wanted a filtered inlet, as well as one that was shielded - the proximity to the follower power supply is fairly close.

Dave

fitzfish 29th September 2011 06:01 AM

Hi Patrick,

Thanks for the link!
Quote:

Originally Posted by EUVL (Post 2728311)
There are some differences in our approaches and choices of components, and Dave and I have been discussing AB tests to optimise both our implementations. But I am too busy right now and is hindering his progress. Sorry about that, Dave.

No problem at all. I am also finding it difficult to tear away from the day job (read all day and most of the night) to do this fun stuff. It is just about 1:00AM here now... We will get to it at some point. I look forward to more data.
Quote:

Originally Posted by EUVL (Post 2728311)
Maybe you should also consider publishing some of your objective and subjective comparisons with the ES9018 evaluation board.

I started taking some measurements to share but ran out of time. The demo board has a few strengths compared to my version of the 9023 but it really sounds and measures poorly in other ways. The time accuracy I spoke about in the previous post for example is subjectively very good on the 9018 demo board. The sound is harsh though and the apparent sound field small compared to the 9023 board.

Don't get me wrong, I think there is potential in the 9018 and plan to build one of my own at some point with a similar approach to that used with the 9023. The 9023 just does so much right for a budget build.

Quote:

Originally Posted by EUVL (Post 2728311)
I am the first to say that I want to build discrete for my own reference system, and the 9022/9023 is not the ultimate DAC available on earth. But when done right, it sounds really damn good, and Dave's different approach has shown that neither of us have really found the optimum of this yet. I sincerely hope that more people will join in to experiment, rather than just copy what we are doing. Only that way can we compare notes and results to discover the remaining potentials of these chip.

I second that!

Quote:

Originally Posted by EUVL (Post 2728311)
One of the test that we plan to do soon is a direct AB comparison between 9022 and 9023, using the same setup.

ASAP…

Dave

abraxalito 29th September 2011 06:40 AM

Quote:

Originally Posted by fitzfish (Post 2728370)
Agreed. My conclusions are based largely on the engineering process and on time spent with a formal education in music. Knowing how these instruments really sound in many different settings is kind of a blessing and a curse…

Sure, comparison with the sound of real instruments is a dead giveaway there's some distortion happening. I prefer voice myself because my own musical experience covers that. But the changes you've been getting probably parallel my own. Whilst I'm not yet sure about time inaccuracy, I am convinced that intermodulation effects are crucial and don't show up on repetitive sinewave testing as you seem to say.

Quote:

Absolutely. My intention was to fit it into a small enclosure to match a headphone/pre amplifier I started some time back. I also was trying to get the lowest possible noise from an AC line supply. The toroids reduce the magnetic induced noise and were easily mounted to the PCB.
Yeah I agree for radiated magnetics they're amongst the best. However on another measure - conducted noise - they're probably the worst owing to their relatively high primary-secondary capacitance. They can easily be an order of magnitude worse than an EI type on this measure.

Quote:

Yes. It is an off the shelf unit available from Digikey. I wanted a filtered inlet, as well as one that was shielded - the proximity to the follower power supply is fairly close.
I hope the mains earth in your set up is jolly clean then, not polluted by PCs or LCDs with noisy SMPSUs. :D Myself I prefer not to rely on the earth quality (it sucks where I am) so much in filtering mains common-mode noise.

qusp 29th September 2011 07:49 AM

Great Job Dave!! what did you end up with in the filter pps? or np0? i cant see close enough to pick out of those 1210 size are panasonic pps or perhaps rubicon hybrid polymer/film. I think you'll find you take a pretty different tack with the 9018, the demo board is not a good indication of this chips sonic abilities.


All times are GMT. The time now is 03:01 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2