New to runeaudio and would just like to say thanks for all the hard work from the developers

I'm running RuneAudio_rpi2_rp3_0.4-beta_20160321_2GB connected via HDMI to a Denon AVRX2200W which should be able to decode native DSD files. Unfortunately I can't get runeaudio to even start playing them.
All other file types play fine and I've enabled DSD in the settings. Have I got hold of 'the wrong end of the stick' in thinking that this is possible and still require a DAC for the Pi?
Cheers,
JMP