Chinese ES9018K2M I2S DAC

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#124
 
#125
The 5532 drops about 2-2.5V from each rail in the output. Which means maximum P-P voltage is about 5V less than supply voltage. With 9V supply the opamp supply is 7.7V, so the max voltage is quite limited, about 700mVRMS or 2.8V P-P.

The OPA2134 (not 2174) swings up to 0.5V of the supply rail, so is much more suited to these kind of conditions and circuits. You will get less distortion - it's simple maths really. It's not a fix for the inherent weaknesses of the board, but helps quite a lot in the running of it.

I am not sure where you got that 11.3 number from. The supply voltage to the board will always be 1.2-1.3V less than the power supply voltage, because that is the drop across the capacitance multiplier at the input of the power section. You are limited to an absolute maximum of 12V at the main supply node, because the 6.3V caps will then have 6V across them. Once you add the 1.2V back, you get 13.2V as the maximum possible input power supply.

If you toss those caps out and replace them with higher voltage units, you can push the main supply node to 15V, because that is the limit of the regulators powering the DAC chip. To remove that limitation, you have to make a significant number of changes and slowly approach the point of diminishing returns.
 
#126
@eziitis, I will definitely consider the suggested boards. Re the change referred to for my existing DAC board, it's a bit over my current skills to implement.

@sangram, so the advantage of the 2134 is the much smaller voltage swing/drop from the supply rail thereby increasing the max voltage to about 6.+ V (?)

The 11.3V came from post#107. I think I understand your explanation re the limitations imposed by the 6.3V caps. But is there really any advantage in increasing the supply voltage from 9V to say it current maximum, and pushing it to say 15V if the caps are replaced - sound wise?
 
#129
dv187736 said:
@eziitis, I will definitely consider the suggested boards. Re the change referred to for my existing DAC board, it's a bit over my current skills to implement.

@sangram, so the advantage of the 2134 is the much smaller voltage swing/drop from the supply rail thereby increasing the max voltage to about 6.+ V (?)

The 11.3V came from post#107. I think I understand your explanation re the limitations imposed by the 6.3V caps. But is there really any advantage in increasing the supply voltage from 9V to say it current maximum, and pushing it to say 15V if the caps are replaced - sound wise?
Click to expand...

I can't judge your present experience or use case, and have no way of working out if you will hear a difference, or by how much. Fact is I have never run the board that low, even with 12V supplies I faced some distortion at the highest volume levels (for example, when feeding an external preamp and pushing software volume to 100%).

If you have a very high gain setup and use software volume (and stay below say 50% of the dial) then no, you might not really benefit from any changes at least in measurements. Still, you are leaving quite a lot of performance on the table this way. It is ultimately up to you to see if you want to do it, and then make your own judgement on whether it was useful or not.
 
#130
@sangram, well said. Apart from the clicks/static that pops up once in a while, and which I think is more of an issue with Audirvana, I find the DAC board quite good for its meager price. The upgrades, well, I can revisit anytime later. Thanks.
 
#132
Hi everyone. I have a dilemma concerning the purchase of the ES9028Q2M board.
Some time ago I ordered a board that arrived with a solder bridge across two pins on the DAC chip (see photo). The seller initially tried to argue that it wouldn't affect the operation of the board. I refused to accept this, because the board had not been professionally assembled and obtained a full refund. I ordered a replacement board from a different seller, which arrived yesterday with exactly the same defect.

Has anyone had a similar problem?
Should I reject this one too? (Its becoming more trouble than its worth!)
Will the defect affect the operation of the chip? I can't find a pinout online , so I can't confirm this for myself.

Comments and opinions would be very much appreciated.
 

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#134
That doesn't look like an accidental application of solder, and the one pin looks like a v ref of some sort, the other a ground. There isn't a bridge on any other pins?

Too bad that company doesn't provide data sheets, what a hassle.
 
#135
phase said:
That doesn't look like an accidental application of solder, and the one pin looks like a v ref of some sort, the other a ground. There isn't a bridge on any other pins?

Too bad that company doesn't provide data sheets, what a hassle.
Click to expand...

Thanks for the reply.
I have attached a photo of the other board. As you can see the situation is identical. As far as I can see there are no other solder bridges on either board. I find it difficult to believe that this is just coincidence.

I can confirm that the two pins in question are connected to ground.

Has anyone else experienced a similar issue, and if so, does it affect performance?
 

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#136
It is near 99% evident it is on purpose/design/normal that these 2 pins are bridged...

Anybody could help on this concern of mine : I want to modify the powersupply : I want to remove the capacitance multiplier (root supplies all board powers ?) which I have no real purpose for (don't like the associated voltage drop), in search of better efficiency (I use regulated buck supply as of now, and will continue to use a regulated one) : I am not sure of how exactly :
simply remove the 2 transistors : the small one and the big one and put a wire link between their most oppositive pins for each ?
 
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#137
No.

Connect the positive terminal of the large input cap to the positive pin of the smaller output cap. Remove the larger transistor, the smaller one has no effect and no current draw when the mains series pass element is removed.
 
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