DSD files usually are 24bit/88.2kHz

The difference is impossible to tell. So the question here is do you have a better dac already to play through and use this only as an amplifier? If so then use it with the front switch on AUX to bypass the dac and plug into your stereo AUX in the back.

If you just have the DSD files and are playing from a PC source, keep the DAC, yes there will be a bit of conversion from your player (foobar/dophamine/or similar) but you will have the nicer dac than your onboard PC chipset.