I've successfully followed these steps to get DSD (.dsf filetype) and SACD (.iso filetype) playing at high bit rate using foobar2000 on my S.M.S.L M500 DAC.
DSD stands for Direct Stream Digital and it is a high-definition lossless audio format with a twist. PCM signal solutions (like FLAC, TTA or APE) measure a set of bits multiple times per second to capture the audio data, hence the 16/24-bit parameter. On the other hand, DSD uses only one bit but samples it 2.8 million times a second to capture the audio signal.