Ok, so I have several DAPs/DACs with different DAC chips. I've listened in, compared, and etc.. And after all this, I'm starting to get a flavor of the difference between the chips and leaning toward believing there are difference with the characteristics of the differenct DACs.
My opinions are based on mostly DAPs so take it for a grain of salt. The best DAC chip to my ears is non-mobile ES9018. I hear more micro details, and the details have variations. Not sure if the HDP R10's amp is adding the warmth, but the warmth really makes it sound real and the resolution is not just caused by sharp treble like the DX90. DX90 includes a mobile version of the 9018 chip different from R10. The LO has more resolution, which leads me to think that the 90's amp section colors it. The 90 has overall cold presentation because of it's bold treble, and lack of mid body definition, whereas R10 has warm, and you can hear more subtle details and the treble has a palette with fine details to thicker. The warmth of the R10 makes the vocals sound extremely real and just really pleasant to listen to. No way does this warmth hide subtalities like the Wolfson's LO in my 5.5G DIYmod. Based on the LO of Wolfson, I would have to say it's warmer than ES chips, and the non-mobile version is the warmer than the mobile version with better ability to output finger resolution. I say, the non-mobile 9018 is in between Wolfson and the mobile 9018, and to be it's a perfect balance.
I also have the Cirrus logic ipod 6G. To me the treble is thick, and doesn't put out subtle details, like the DX90. The cirrus gets closer to the mobile ES sound. The sound has lots of energy though as it's punchy with my pure ii, as other LO does not get so punchy in it's presentation.
I've tapped into the LOs. All this makes me think these chips have characteristics of their own. If you have revealing monitors you can pick up on these differences. I think my NT-6 does a great job at it.