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DIY ES9826Q ADC for amps FR measurements etc

MCH

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Apr 10, 2021
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hi,
I have a DIY amp project going on and have a couple of square cm left on a PCB (not the amp pcb). I thought it could be neat to use that extra space to add a simple ADC to measure mainly amplifier frequency response and maybe some other random measurements without risking my good ADC. I don't need much accuracy, just something that if i break i wont cry. the idea is to interface it to a raspberry pi via i2s or use the spdif output. I have used before a cheap interface (M-track solo) but its frequency response is not flat 20-20k to start with... and there are not many other options with differential inputs below 50 euros that i know of.

I have been looking around and came across of ESS ES9826Q, that seems to check all the boxes. It is very cheap, it has a hardware mode with very little components (not even op-amps are necessary), input impedance is selectable 2.5-10 kOhm (seems low? i have seen there is a debate on the subject but it is above my paygrade, i only want to measure frequency response, not high performance DACs).
But i have found next to no information online besides the datasheet, maybe the chip is too new.

1714916899207.png


In any case, before moving forward. Am i missing something? is there a "to go" adc for these sort of projects? my requirements are:
- Hardware mode
- differential inputs
- very cheap and low component count and cost
- i2s and/or spdif outputs, preferably both

thanks!
 
OP
M

MCH

Major Contributor
Joined
Apr 10, 2021
Messages
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2,396
With two voltage dividers built in to attach directly to the power resistor used as the amplifier load, and the option to bypass to use as regular line level balanced ADC.
- SPDIF out.
- Hardware mode, only needs 5V input to work.
- All in 25x55 mm and a BOM of 29 components at, I would say, total cost of less than 15 euros... If this performs anywhere near the datasheet, it could be a handy gadget to have around.

1715280583149.png

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