for your information. i am selling my 502DAC PRO on ebay. I am selling it, because it is not an active product from PI2 Design anymore.
(w/WM8804 Digital, Isolated AES/EBU Single Ended and Balanced out, Toslink, PCM1792 DAC and LME49600 Headphone Amplifier, with acrylic clear case)
this is your chance to make your experience with it.
I only played it with RCA output (volumio 2.146 and Hifiberry DIGI+ PRO driver)