Had fun building a DIY HiRez DAC to take to CAF2016 earlier this month. It was used in the DCAudioDIY room with a Linux based music server. Have attached the build document to look over.
This one uses the Amanero async USB to I2S Bus adaptor and a AK4490EQ DAC board from Ebay. There is also an AK4495EQ board as well that I will be trying soon as a comparison.
The output stage opamp is socketed, so the AD827 dual opamp can be changed. I have an LME49720 in it now, and will be trying Burson opamps soon.
Biggest part of this is the minimum phase DAC recostruction filter in use. This has been used by many folks with the original Wolfson Micro WM874x series DAC's, and now others have started adding them, but not calling them minimum phase filters.
This has been my preferred DAC filter method over the last 6 years.
Hope folks find it interesting, and remember, this uses AC line voltage, so protect yourself and be careful. Fuses are important.