If you decide to audition new DACs I would suggest you consider the Berkeley Alpha DAC. I don't have any experience with your equipment and have only heard the Berkeley once when auditioned by a dealer. Like everything else the true test is having an opportunity to hear it in your system.
http://www.computeraudiophile.com/Berkeley-Audio-Design-Alpha-DAC-Review
http://www.computeraudiophile.com/Berkeley-Audio-Design-Alpha-DAC-Review