In case anyone missed it : http://www.diyaudio.com/forums/diyaudio-com-articles/172983-zen-i-v-converter.html
This is significant in that the D1 stage has been highly regarded as one of the best DAC analog stage to use for over 15 years. There have been a lot of complex ideas floating around in the DIY community the past decade but none I have found sound as good as the D1.
For Nelson to endorse this it is definately worth a look. I may try this out on my 1862 DAC.