Interesting that you mentioned the Monarchy DAC. Here is a review from Lynn Olson that explains some of the benefits of using 20 bit versus 16 bit, at least in this implementation:
http://www.positive-feedback.com/Issue25/monarchy_m24.htm
some interesting facts about bit resolution.
http://www.positive-feedback.com/Issue25/monarchy_m24.htm
some interesting facts about bit resolution.