Mac 501 cd player or MDA 1000 d/a converter

Has anybody used the Mcinstosh mda1000 d/a converter on the Mcintosh mcd301. I was considering purchasing the 500 but thought I should keep the 301 and link up the mca1000 for better sound. Is the 500 better than the 301/1000 solution?
I haven't heard either, but you might want to try digging this (or posting) at the McIntosh forum within