No, a DAC adds a small amount of noise, called Dither aka Noise Shaping. More dither is needed for a lower-precision digital format. Increasing "precision" by adding zeros fools the DAC into not adding
enough dither, which may result in digital harshness on the output (albeit at a very low level). Decreasing precision by truncating, without dither, has the same problem.
http://www.digido.com/articles-and-d...16-dither.html
https://en.wikipedia.org/wiki/Dither#Digital_audio