foobar is a free music playback program which can be configured to support bit-perfect hi-res audio playback. It can be downloaded here: http://www.foobar2000.org
Along with foobar, you'll want to download the ASIO component: http://www.foobar2000.org/components/view/foo_out_asio
If you have DSD files, foobar can be configured to output DSD following this guide: http://www.audiostream.com/content/how-play-dsd-file-using-foobar2000#eG3ty3joQap3rrKl.97
(DSD Playback Method should be set for DoP Marker)
Next you'll need to make sure your Grace playback hardware is set for U2 mode (if available) and that it's driver is properly installed.
Once you have your driver installed and the ASIO component installed in foobar, go to file > preferences > playback > output and select the Grace ASIO driver for your playback device. foobar should now send bit-perfect data to your hardware at the correct sample rate for the source material.
Enjoy the music!