Hi Paul,
Schematic by MrSlim here: https://www.diyaudio.com/forums/digital-line-level/314935-es9038q2m-board-301.html#post5577605
Also, in posts below that one some discussion about balanced outputs, if desired.
I was also asked to write up a how-to for building a version using through-hole components. It is too big to post here, it is in my dropbox here: Dropbox - Output Stage Instructions.zip
MrSlim also posted an AVCC schematic. I was also asked to use through-hole as much as possible for that, so the film cap is quite physically large. I think Mouser carries a Panasonic 10uf stacked film SMD cap that would be much smaller. For my first dac board I used a 10uf ceramic SMD cap which is not as recommended for use with the voltage reference, but may be good enough for our use, not sure.
Schematic by MrSlim here: https://www.diyaudio.com/forums/digital-line-level/314935-es9038q2m-board-301.html#post5577605
Also, in posts below that one some discussion about balanced outputs, if desired.
I was also asked to write up a how-to for building a version using through-hole components. It is too big to post here, it is in my dropbox here: Dropbox - Output Stage Instructions.zip
MrSlim also posted an AVCC schematic. I was also asked to use through-hole as much as possible for that, so the film cap is quite physically large. I think Mouser carries a Panasonic 10uf stacked film SMD cap that would be much smaller. For my first dac board I used a 10uf ceramic SMD cap which is not as recommended for use with the voltage reference, but may be good enough for our use, not sure.
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Paul,
I simulated your OP stage / low pass filter and ran a 20kHz square wave
through it, check below.
It shows pretty bad transient response. This is because the LPF is not linear
phase. This will affect the sound adversely.
For a DAC like this with significant HF energy, I recommend a 3rd order,
Bessell or Gaussian low pass filter response which will have perfect square
wave with rounding and no overshoot.
Further to this, I would not use Vero board. Uae a solid copper covered piece
of board as a ground plane and mount everything, usually dead bug style.
You can do PS bypassing direct to GP and keep everything really optimum.
For the LPF values, download a free filter design program, the rest is easy.
If you guys are trying to get really high performance out of this DAC, best do
things properly.
T
Attachments
Hi Terry,
It is a nominally 70 kHz Guassian LPF that we use (not the schematic you used there, and that Paul asked about), with component values reasonably close to desired. I believe Paul is now planning to build our current version. Aside from I/V cap value, the time constants are pretty much exactly the same as a DAC filter published years ago by Scott Wurcer. In addition, it sounds fine. I'm not going to worry about measuring and fine tweaking that part now, since there are bigger issues to take care of.
Regarding dead bug layout, what we use is as close as it is going to get with many components soldered directly to the ground plane. I was asked to do a through-hole component layout beginners could do. When I did my own first one I did it very differently, perhaps more like you are suggesting, but it scared too many people away from trying it. Dac mods are worthless in this case if nobody wants to build one. Hopefully, Paul and any other folks interested in modding the Chinese dac board will decide to go ahead with it as the downloadable how-to shows.
Speaking of all that, you would be welcome to build one yourself. Then you might be able to help with some work in areas that still need more attention. As it is now I have to figure out how to do it all myself.
It is a nominally 70 kHz Guassian LPF that we use (not the schematic you used there, and that Paul asked about), with component values reasonably close to desired. I believe Paul is now planning to build our current version. Aside from I/V cap value, the time constants are pretty much exactly the same as a DAC filter published years ago by Scott Wurcer. In addition, it sounds fine. I'm not going to worry about measuring and fine tweaking that part now, since there are bigger issues to take care of.
Regarding dead bug layout, what we use is as close as it is going to get with many components soldered directly to the ground plane. I was asked to do a through-hole component layout beginners could do. When I did my own first one I did it very differently, perhaps more like you are suggesting, but it scared too many people away from trying it. Dac mods are worthless in this case if nobody wants to build one. Hopefully, Paul and any other folks interested in modding the Chinese dac board will decide to go ahead with it as the downloadable how-to shows.
Speaking of all that, you would be welcome to build one yourself. Then you might be able to help with some work in areas that still need more attention. As it is now I have to figure out how to do it all myself.
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No, not in a absolute sense. I meant that my intent started out to be to help people mod low cost dacs so that more people could afford to have better dacs.
However, at this point the mods have gotten so extensive about all I am still using is the dac chip, the board's ground plane, and the MCU (only part of the time for the MCU). I had no idea the pursuit would lead where it has, but I still would like at least a few people to fully mod one. The reason for that is so that more people than just me can have an opportunity to hear how one can sound, and maybe an opportunity to compare it with other dacs.
Things changed somewhat when Allo came out with Katana, especially v1.2. With linear power supplies it probably costs more than a modded dac, but it is very close in sound quality. In effect, they both sound like ES9038Q2M dacs that a lot of effort has been put into trying to do a good implementation. I'm not done yet, though. And when I finish I hope to have a dac pretty close to as good as a Q2M is likely to get, and one that can serve as a general purpose dac. Obviously, some more work to do with AK4137, a master mode option, and possibly external DSP filtering. However, that risks making it all the less likely anyone will fully mod one, given the amount of time and effort involved.
Now, if I may, maybe I could ask you a question: You asked if I was sure. Should I not be?
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Hi Markw4!
I want to ask advice as an expert on this DAC. Order with es9038q2m aliexpress from ustars Lusya ES9038 Q2M DSD DAC декодер Поддержка IIS DSD 384 кГц коаксиальный волокна DOP для Hi Fi усилитель аудио с OLED G4 009 купить на AliExpress. But the seller sent me the product wrote that it was not available and that he sent me this Page Not Found - Aliexpress.com -Fiber-input-384KHz-DOP-with-OLED / 314284_32950289780.html? Spm = 2114.12010612.8148356.36.2f344618lJjuvh. I have contacted the aliexpress support service and they have already agreed with the seller that the money will be returned to me through a dispute on the 11th day after
sending. This is the case if I open a dispute. The seller has already written about the agreement. Question: Is it necessary to abandon this version of es9038q2m? Or let the goods come in and I can also improve it as the version discussed here on the forum?
I want to ask advice as an expert on this DAC. Order with es9038q2m aliexpress from ustars Lusya ES9038 Q2M DSD DAC декодер Поддержка IIS DSD 384 кГц коаксиальный волокна DOP для Hi Fi усилитель аудио с OLED G4 009 купить на AliExpress. But the seller sent me the product wrote that it was not available and that he sent me this Page Not Found - Aliexpress.com -Fiber-input-384KHz-DOP-with-OLED / 314284_32950289780.html? Spm = 2114.12010612.8148356.36.2f344618lJjuvh. I have contacted the aliexpress support service and they have already agreed with the seller that the money will be returned to me through a dispute on the 11th day after
sending. This is the case if I open a dispute. The seller has already written about the agreement. Question: Is it necessary to abandon this version of es9038q2m? Or let the goods come in and I can also improve it as the version discussed here on the forum?
извините, эта ссылка Page Not Found - Aliexpress.com 314284_32950289780.html? SPM = 2114.12010612.8148356.36.2f344618lJjuvh
sorry, i'm from Russia and use translate on this page. Lusya ES9038 Q2M ЦАП DSD декодер поддержка IIS DSD коаксиальный волокно вход 384 кГц DOP с OLED T0012 купить в магазине LusyaTechnology Store на AliExpress - this
Hi 888777,
It looks to me like the seller you ordered from accidentally made the price too low, and had to remove the offer. You should get your money back, and then order from another seller.
The dac boards are much lower cost without the display, but with the display they cost much more. Personally, I don't use the display, but some people like to have it. The main reason I can think of for using the display is to make it easier to access dac chip registers using I2C bus.
After you get your money refunded, you might try ordering from one of these sellers:
Lusya ES9038Q2M I2S IIS DSD доп коаксиальный SPDIF волокна цифровой аудио ЦАП Декодер доска поддержка 32bit 384 К/DSD64 DSD128 DSD256 купить на AliExpress
Lusya ES9038 Q2M ЦАП DSD декодер поддержка IIS DSD коаксиальный волокно вход 384 кГц DOP с OLED T0012 купить в магазине LusyaTechnology Store на AliExpress
Then you can decide if you want to pay the higher price for a dac board with display, or not.
Sometimes some people have said that, but saying it doesn't make it true. However, it can be useful thing to say at times to make people think about their online behavior. In reality, people are very complex and it can't be that everybody always does everything they do for one simple reason. We know they don't.
Getting closer to being ready to try AK4137 in DSD slave mode. Pics attached below.
It can be seen there is an extra 3-pin header on the AK4137 seizure relay board which is for monitoring AK4137 I2C bus. Plan is to use those header pins as test points to capture normal MCU control of AK chip using a cheapie $10 logic analyzer. The cheap little USB logic analyzers work fine for capturing and decoding I2C bus activity. However, it takes about a $700 USB logic analyzer for use with I2S bus. Big difference in speed between the two busses, and that's why I can only capture I2C bus.
It can be seen there is an extra 3-pin header on the AK4137 seizure relay board which is for monitoring AK4137 I2C bus. Plan is to use those header pins as test points to capture normal MCU control of AK chip using a cheapie $10 logic analyzer. The cheap little USB logic analyzers work fine for capturing and decoding I2C bus activity. However, it takes about a $700 USB logic analyzer for use with I2S bus. Big difference in speed between the two busses, and that's why I can only capture I2C bus.
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Hi 888777,
I am sorry it looks like made a mistake with the two links I suggested. Last time I checked, the old boards we use were still available. Please let me look again before you order.
There is this one, but it is expensive:
Новый ES9038 ES9038Q2M ЦАП Декодер совета Поддержка IIS DSD 384 кГц коаксиальный Оптический DOP для Hi Fi усилитель аудио с TFT дисплей купить на AliExpress
This looks better:
ES9038 Q2M DSD DAC декодирования плата поддерживает IIS DSD 384 кГц коаксиальный волокна доп купить на AliExpress
You can even use one of the blue boards. They are a bit more cheaply made and there is no display option for them, but they can be made to work okay:
ES9038 Q2M I2S DSD оптический коаксиальный Вход декодер USB DAC наушников Выход HiFi аудио платы модуля усилителя купить на AliExpress
I am sorry it looks like made a mistake with the two links I suggested. Last time I checked, the old boards we use were still available. Please let me look again before you order.
There is this one, but it is expensive:
Новый ES9038 ES9038Q2M ЦАП Декодер совета Поддержка IIS DSD 384 кГц коаксиальный Оптический DOP для Hi Fi усилитель аудио с TFT дисплей купить на AliExpress
This looks better:
ES9038 Q2M DSD DAC декодирования плата поддерживает IIS DSD 384 кГц коаксиальный волокна доп купить на AliExpress
You can even use one of the blue boards. They are a bit more cheaply made and there is no display option for them, but they can be made to work okay:
ES9038 Q2M I2S DSD оптический коаксиальный Вход декодер USB DAC наушников Выход HiFi аудио платы модуля усилителя купить на AliExpress
Hi Paul,
Happy holidays, and of course I am very happy to help as I am able.
Also, happy to hear of your intention. A proper output stage can do a very good job of finishing audio processing of what comes out of the dac chip.
Since I am sort of the spokesperson in this thread for trying to encourage getting the best we know how of ES9038Q2M, I hope it will be okay if say a little more about it:
What comes out of the dac chip is dependent on a number of things. One of the most critical things to affect dac outputs is the AVCC voltage for each channel. Any noise or other variation there will produce noise and intermodulation distortion at the dac output. Therefore, it is critical that AVCC be extremely stable, low noise, and of low source impedance. Some information about a recommended AVCC supply and distortion numbers based on using different opamps for AVCC and output stage can be found here: http://www.esstech.com/files/4514/4095/4306/Application_Note_Component_Selection_and_PCB_Layout.pdf The application note at that link was put together for use with ES9008 dac chip and much of it is still very applicable. However, we have made a few changes from the old ESS application note recommendations to what we recommend now for the ES9038Q2M modding project, but reasons for doing what we do are essentially still the same things ESS was trying to get people to give attention to with ES9008.
The reason for saying most of the foregoing is to try to explain why I strongly recommend doing something with AVCC as part of an output stage project. Don't know if you are thinking about that same way I do or not. If you are, sorry for all the verbiage. If not, well, I hope you will keep it in mind as your undertaking progresses. It can be an add-on at any time.
-Mark
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Mark,
the seller is waiting for a response from me. either returns me the money through a dispute, or sends me this one with a display Lusya ES9038 Q2M ЦАП DSD декодер поддержка IIS DSD коаксиальный волокно вход 384 кГц DOP с OLED T0012 купить в магазине LusyaTechnology Store на AliExpress. Can you say something about this version? Very similar to the one that is being discussed here. Moreover, the seller is ready to send me for that price, which is closed on the lot. It is tempting. But I do not want to be deceived by the poor implementation of the chip.
the seller is waiting for a response from me. either returns me the money through a dispute, or sends me this one with a display Lusya ES9038 Q2M ЦАП DSD декодер поддержка IIS DSD коаксиальный волокно вход 384 кГц DOP с OLED T0012 купить в магазине LusyaTechnology Store на AliExpress. Can you say something about this version? Very similar to the one that is being discussed here. Moreover, the seller is ready to send me for that price, which is closed on the lot. It is tempting. But I do not want to be deceived by the poor implementation of the chip.
Blue board is YJ company. They have store on taobao. I brought in 2017 year dac xmos pcm5102 384khz red board on aliexpres. I don't know what dac of YJ. I have modded this board. But she have many bad electronic elements on board. And I will not use this - bad sound. Now I use Asus xonar d1.