low cost ADAU1452 China board...

You can make a very simple angle adapter
20240826_221157.jpg
 
Think I will just go forward with the CS42448 codec card. It is easy to desolder the output components and make my own with components that dont have worse spec than the codec. And using it differential 4 channel out.
Just 2 x 40$ for two combos.
 
To verify the measured results, I performed a simple LTSpice simulation of the DAC output filter with opa1612. The simulation qualitatively confirms the measurements. Therefore, opa1612 needs to be replaced!

Whereas opa2340 looks fine !
 

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Hm tried a soic OP1678, thinking it is a opa2340 equivalent.
I’m not a good smd solderer but checked for shorts and connections.
Terrible noise floor at-80 dBu. Distortion masked by the noise
The original opamp has about -120 to -130dBu noise in same passive components. (But terrible HD as discussed)

How is that possible. What can be the user fault😝
 
I think my board/codec has some damage.
Do you get the same result with 1.5 volt common mode? That is adding a 1.5 volt dc to your signal.
That is what a working board outputs from the codec
Sorry, I had put a cap on the input for some dumb reason and also forgot sig gen is Vpp not RMS, so ignore my previous post. It can put out around 0.5Vrms with 1.5V common mode on 5V supply. OPA2340 can put out 1Vrms, so twice as much.
 
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