Hi @doboree
The N-05 was launched sometime in 2015 if my memory serves me right. Today's dac's are almost a few decades, if not a generation ahead in technical advancements. Thus, the N-05 XD should be improvement over the older N-05 by a considerable margin I would presume. I have their K-01, which has a similar dac implementation to the N-05 with AKM chips. The newer N-05 XD is a completely newer implementation of their in house developed dac and a different sound completely.
Going for a N-05 today, will be a step back in time in my honest opinion. All the best.