Really good review. Just make sure you update the Mids Sound Chip as the Sabre ES9018 not the Sabre CS4398, the chip you wrote is the Cirrus Logic CS4398.. Whoops, simple mistake.

Oups, my mistake...got confuse with all this strange DAC name...thanks for letting me know!

Lol.. It's fine.. Just noticed it and wanted to help you make it right.

Hi mate, nice review.
 
I can see that you still use the original Pisen battery on the picture. Have you ever tried other batteries? Which battery?
 
Since I've bought my DX90 in 2014, I use it with another battery, a Ravpower 2250 mah for my part. Easy to buy where I live. (Btw I just noticed after writing this that you're a French speaker )
I find the sound slightly better overall, slightly more tight, precise, spacious. Impossible to use the Pisen one after this.
Now I use only the pisen to burn my new earphones in.
 
Since I am not in America, I can't buy the Hyperion and the Gorilla gadgets battery to try it, they don't ship overseas.  :'(
I found an other way to buy it but way more expensive...
 
Well, recently I sent my DAP for modding in Russia and I can't be more happier, everything is better, gain, line out, soundstage, precision.
The perfect DAP for this price
 
Cheers