Hello,
I bought a ES9038Q2M dac from audiophonics for a complete dac + amp + speaker project. First i bought a ES9038Q2M with a screen and pot to adjust the volume and select the source, but as it was out of stock i had to go with this dac instead :
ESS ES9038Q2M DAC Module I2S Optical Coaxial 32bit 384khz DSD256 - Audiophonics
As often with chinese thing like that, audiophonics just resell it and the technical information are seriously lacking. Over the years i have several talk with the guy from audiophonics technical service, and i must i really don't like him. He obviously doesn't know anything about the stuff they sell and he doesn't want to look very hard...
So when i ask them what kind of pot i should use to adjust the volume and how the source is selected, they answer any pot will do and that the dac will automatically lock to the signal it detects.
Of course it is not the case. 😡
I tried with a standard Lin pot and it doesn't adjust the volume between 0 and 100%, more between 50-70% to 100%.
And for the source selection, only the mode button on the board can select the source.
Automatic selection looked coherent because i don't see people to open the case to press the mode button every time they want to change the source 😱
But apparently the chinese didn't think that way 🙁
From what i understand the dac is control by a N76E003AT20 ic from Nuvoton. There is the mode and vol + and - button, plus a connector for a pot (3v3 VOL GRD). There is also a space for a 5 pin connector on the top of the ic, but as there is no documentation i don't know what it is doing, maybe a way to connect an external source switch 😕
So as audiophonics doesn't want to answer me about this, i hoped someone here would be kind enough to advice me how to make this thing to work properly 🙂
I bought a ES9038Q2M dac from audiophonics for a complete dac + amp + speaker project. First i bought a ES9038Q2M with a screen and pot to adjust the volume and select the source, but as it was out of stock i had to go with this dac instead :
ESS ES9038Q2M DAC Module I2S Optical Coaxial 32bit 384khz DSD256 - Audiophonics
As often with chinese thing like that, audiophonics just resell it and the technical information are seriously lacking. Over the years i have several talk with the guy from audiophonics technical service, and i must i really don't like him. He obviously doesn't know anything about the stuff they sell and he doesn't want to look very hard...
So when i ask them what kind of pot i should use to adjust the volume and how the source is selected, they answer any pot will do and that the dac will automatically lock to the signal it detects.
Of course it is not the case. 😡
I tried with a standard Lin pot and it doesn't adjust the volume between 0 and 100%, more between 50-70% to 100%.
And for the source selection, only the mode button on the board can select the source.
Automatic selection looked coherent because i don't see people to open the case to press the mode button every time they want to change the source 😱
But apparently the chinese didn't think that way 🙁
From what i understand the dac is control by a N76E003AT20 ic from Nuvoton. There is the mode and vol + and - button, plus a connector for a pot (3v3 VOL GRD). There is also a space for a 5 pin connector on the top of the ic, but as there is no documentation i don't know what it is doing, maybe a way to connect an external source switch 😕
So as audiophonics doesn't want to answer me about this, i hoped someone here would be kind enough to advice me how to make this thing to work properly 🙂
We know all about that DAC board. Please see the ES9038Q2M Board thread. ES9038Q2M Board
Regarding the pot, the full range of the pot is not used very effectively by the dac board. Putting a resistor in series with one of the pot ends (not the wiper) can make the adjustment feel more right. Don't recall offhand which end to put the resistor on, but you could try one end or the other. I used a 10k pot and 10k series resistor, IIRC. To understand how that works, the pot wiper is provides a DC signal read by an ADC inside the MCU. The DAC volume is then actually controlled digitally by the MCU writing to the DAC chip I2C volume registers which are actually configured as attenuation registers. Thus, when the pot wiper is at ground there is zero attenuation. Putting a resistor in series with the pot +3.3v end should reduce the maximum attenuation to keep it within the desired control range, again IIRC.
Regarding the pot, the full range of the pot is not used very effectively by the dac board. Putting a resistor in series with one of the pot ends (not the wiper) can make the adjustment feel more right. Don't recall offhand which end to put the resistor on, but you could try one end or the other. I used a 10k pot and 10k series resistor, IIRC. To understand how that works, the pot wiper is provides a DC signal read by an ADC inside the MCU. The DAC volume is then actually controlled digitally by the MCU writing to the DAC chip I2C volume registers which are actually configured as attenuation registers. Thus, when the pot wiper is at ground there is zero attenuation. Putting a resistor in series with the pot +3.3v end should reduce the maximum attenuation to keep it within the desired control range, again IIRC.
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Thank you, i didn't saw there is a nearly 600 pages topic on this dac 😀
I have a 500 ohm pot, i will try with some resistor to see.
It's not that i am lazy but it's a very long topic... About the source selection, is there a way to get automatic source selection like audiophonics said or at least externalize it properly without directly solder to the "mode" button pins ?
I have a 500 ohm pot, i will try with some resistor to see.
It's not that i am lazy but it's a very long topic... About the source selection, is there a way to get automatic source selection like audiophonics said or at least externalize it properly without directly solder to the "mode" button pins ?
The mode button is read by the MCU which then programs the dac chip I2C registers to use the appropriate input. There is no harm soldering to the mode button pins or the MCU pins that read the mode button pins. Probably one pin is connected to ground and the other one may be pulled by with a resistor somewhere (maybe inside the MCU) to +3.3v or thereabouts. In that case the ground connection for an external button could be picked up anywhere.
EDIT: Other than the above, if there is automatic selection of I2S, SPDIF, or TOSLINK that could be done by the MCU until it finds a dac input with data coming in. However, it might not switch from that input until it stops and another input is used. Basically, the MCU would have to use the dac chip to scan the inputs until it found something it could play. It should be possible to do that, but the earlier version boards didn't have it.
EDIT: Other than the above, if there is automatic selection of I2S, SPDIF, or TOSLINK that could be done by the MCU until it finds a dac input with data coming in. However, it might not switch from that input until it stops and another input is used. Basically, the MCU would have to use the dac chip to scan the inputs until it found something it could play. It should be possible to do that, but the earlier version boards didn't have it.
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