It helps to know the details of A/B comparison setup. How do we set it up? Please share.
I have bought this ES9038Q2M DAC Module and plan to connect it to Raspberry pi 4.
I am a novice in DIY Audio and I want to know the my question might be stupidly basic
but it isn't very clear and the available information on this board doesn't help either. I am planning to power it using a 15V DC jack. However, I don't understand the purpose of 5V VDD pin on the I2S Input connector. Do I need to provide 5V to this pin in addition to the 15V DC through DC jack?
I have used simple DACs such as MAX98357A DAC modules for some Arduino projects but they only had one Vin pin. So could you please tell whether I need to connect the 5V on I2S connector or not?
I am a novice in DIY Audio and I want to know the my question might be stupidly basic
but it isn't very clear and the available information on this board doesn't help either. I am planning to power it using a 15V DC jack. However, I don't understand the purpose of 5V VDD pin on the I2S Input connector. Do I need to provide 5V to this pin in addition to the 15V DC through DC jack? I have used simple DACs such as MAX98357A DAC modules for some Arduino projects but they only had one Vin pin. So could you please tell whether I need to connect the 5V on I2S connector or not?
The 5v pin on the I2S connect is usually an output, at least on one of these types of boards. It might be used to help power a USB board or something like that. I am not aware of anyone in the thread using that 5v output for anything.
Other than that, these boards tend to sound not very good in their stock form. The tend to sound better if powered from +-15v, and if the output stage is redesigned. A good quality USB board may help too. Almost everything about these boards except the ES9038Q2M chip is designed to be as cheap as possible. The components are low quality to save money, the circuity is oversimplified to save money, etc. That's why the boards a fairly low cost. However, they can be good for learning about dacs and learning about modding them.
Other than that, these boards tend to sound not very good in their stock form. The tend to sound better if powered from +-15v, and if the output stage is redesigned. A good quality USB board may help too. Almost everything about these boards except the ES9038Q2M chip is designed to be as cheap as possible. The components are low quality to save money, the circuity is oversimplified to save money, etc. That's why the boards a fairly low cost. However, they can be good for learning about dacs and learning about modding them.
How did you test for that? Please share for the sake of others who may be contemplating on purchasing one.
FWIW, I have two of these generic ESS9038Q2M boards and have absolutely no complaints about the sound quality. Put one in the pre-amp of my main system and the other in a stand alone DAC box.
I do know the supplied instructions aren't great, so if you have more questions I'd be happy to help.
My boards are not 100% identical to yours, but very, very similar.
For starters, here's the board schematic. Again, not 100% but close enough to give you a good idea of what's there.
I do know the supplied instructions aren't great, so if you have more questions I'd be happy to help.
My boards are not 100% identical to yours, but very, very similar.
For starters, here's the board schematic. Again, not 100% but close enough to give you a good idea of what's there.
Attachments
If someone cares read the thread there have been several measurements of THD carried out for the board in original state by myself and other users. Typically it is in the range of -85-90 dB and populated with odd harmonics as well
The number stated in the ESS9038Q2M data sheet is -120dB.Good for you then, but running the DAC in voltage mode as it is on the original board is far from the real capabilities of ESS9038Q2M.
Moreover, if one considers to use I2S input (+ USB transport module required additionally) then the Khadas Toneboard 1 for 80 USD is much more sensible option. It runs in current mode, has USB transport onboard and powered by USB delivers about -110dB THD.
I would conclude, that unless one is OK with mediocre sound, the board above is just a toy for the modding hobby.
@Markw4 @bohrok2610 @techtool Thanks for the explanation.
So I have tried testing the board with simple setup. Since my Raspberry Pi has arrived yet I used an ESP32 for this purpose. Here is the connection diagram
The ESP32 is programmed to play internet radio stream and works well with this Adafruit DAC Module. I thought it would be a plug & play replacement for the Adafruit DAC, however, with ESS9038Q2M board there is no sound output. I have tried both the 3.5mm jack as well as RCA output. By default the PCM led is ON. I guess that should be the right input selected for I2S input. Correct?
However, I understand that by pressing mode button I can switch between different input modes but what's the purpose of LOCK Mode? Also long pressing the mode button makes the led on the selected mode blinking. Could someone please explain what does that do?
So I have tried testing the board with simple setup. Since my Raspberry Pi has arrived yet I used an ESP32 for this purpose. Here is the connection diagram
The ESP32 is programmed to play internet radio stream and works well with this Adafruit DAC Module. I thought it would be a plug & play replacement for the Adafruit DAC, however, with ESS9038Q2M board there is no sound output. I have tried both the 3.5mm jack as well as RCA output. By default the PCM led is ON. I guess that should be the right input selected for I2S input. Correct?
However, I understand that by pressing mode button I can switch between different input modes but what's the purpose of LOCK Mode? Also long pressing the mode button makes the led on the selected mode blinking. Could someone please explain what does that do?
Does the LOCK light go on? It shows that dac chip is locked onto an digital input signal. If not locked there will be no sound. The I2S input should be selected with the MODE button or DIP switches, whatever it is for this board. Should be a diagram somewhere in one of the ads where they sell those things that explains how to select the input source between I2S, SPDIF, TOSLINK. Also should explain how to select digital reconstruction filter type.
Otherwise this is where having a scope can be super helpful. You have one?
Regarding the PCM light, in one sense the two alternatives are PCM or DSD. Don't know if both those lights also imply the I2S input is selected.
Otherwise this is where having a scope can be super helpful. You have one?
Regarding the PCM light, in one sense the two alternatives are PCM or DSD. Don't know if both those lights also imply the I2S input is selected.
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There are a couple of things you should check. First is the pinout of your ESP32. Check which GPIO pins the ESP32 firmware uses for I2S (BCK, SD, LRCK). Also check the I2S format. Is it standard I2S or left justified. The ES9038Q2M probably uses standard I2S as default.
No the LOCK led doesn't turn on. There is a push button for mode selection and it works fine. However, it only cycles between PCM, OPT and COAX input. It doesn't go to DSD.
Yes I have found the following for the digital filter selection using the DIP switch:
but I am not familiar with these filters. I suspect they have an effect on the audio quality and I should be able to get at least some output without changing these filters.
Yes I do have a scope. What do you suggest should I check for?
The GPIO pins on ESP32 are correct as I have used the same pins with different basic DAC modules and even the same sketch.
Regarding the I2S format, I believe it's standard I2S as one of the other DAC modules has standard one by default and the same pin connections and sketch works fine.
Markw4 stated, "sound not very good", talking about what we hear. It would require listening comparison, no? In such case, how would one set up and carry out the process?If someone cares read the thread there have been several measurements of THD carried out for the board in original state by myself and other users. Typically it is in the range of -85-90 dB and populated with odd harmonics as well
See above question.
On my boards the input selection is done with jumpers which are equivalent to your DIP switches. Two are used for the input selection and three for the filter selection. In your case, since the filters are on DIP 1-3, I think the input selection will be done with DIP 4 & 5. I am at work now so I don't have access to my info but I can send it to you later. The ES9038 data sheet has lots of info about the performance of the various filters, but if I remember correctly, all of them don't start to roll off until over 20 KHz, so they really don't have any effect that can be heard. And yes, you should get an output not matter which filter is in use.
First thing to do with a scope is to check the I2S signals look correct and are going to right pins on the dac board. Its also possible to see what the I2S format is by adjusting the volume level in the OS of fixed sine wave signal. One can see how the LRCK and DATA bits line up. IIRC, I found some example pics of how to do that at JL Sounds, but don't remember exactly where. I saved a copy for myself because I thought it was clever to do with a scope. My dropbox copy is at: https://www.dropbox.com/sh/flsrfvqt7l40lc2/AACOlZYExMOyHxFZJZnl-iTna?dl=0
Regarding DSD verses PCM, the dac is probably programmed to auto select whichever format it detects coming in. The MCU should note the status of that and illuminate the correct LED
Regarding filters, if the default filter doesn't sound best there is usually something wrong with dac implementation, typically with the output stage. Doesn't always work out that way for all people of course. YMMV.
Regarding DSD verses PCM, the dac is probably programmed to auto select whichever format it detects coming in. The MCU should note the status of that and illuminate the correct LED
Regarding filters, if the default filter doesn't sound best there is usually something wrong with dac implementation, typically with the output stage. Doesn't always work out that way for all people of course. YMMV.
Not all DACs with low THD sound good, because it is only one factor what matters. Correspondingly none of the DACs with high THD sound good. The meaning of “sound good” is something of individual perception, since a small fraction of listeners have an addiction to the distorted sound, particularly polluted with even harmonics. I wish them very happy listening, because it is none of my business.
And my question was, how does one set up and conduct the listening session? Comparison is a must in order to establish a reference point to know if something sounds good or bad. What does the comparison setup look like in detail? Please share.
How does one figure that out?
No, I won’t. This is one of my best guarded secrets, not to be shared publicly. Especially on Fridays night…🥸