My aim is to have a high end 2 channel ADC for professional grade recording

I've googled out my favorite ADC chip PCM 4220 or PCM4222, just wonder what model of portable interface uses this chip??

Is there anyway to know what ADC and DAC does the interface use without breaking open the case?

Or I should go DIY?

What makes this your "favourite" chip? From the data sheet, it looks pretty good, but nothing really special. You need to remember than the implementation of the chip will have a large effect on it's real-world performance. A device with a great chip and poor design will often perform worse than a device with an average chip and excellent circuit design.

Unless you can find a tear-down on the internet, then no.

Do you have experience with ADC circuit design? Power supply design? Digital interface design? If no, your DIY efforts are likely to teach you a lot, and generally be a good experience - but you aren't likely to end up with something better than the equivalently priced commercial offering on your first effort. It's worth a try - at worst you'll learn a whole lot about how not to design an audio circuit