Just got my unit yesterday, was wondering the same and chanced upon your question haha.Thanks for the info. No, the volume was not maxed out in PRE - and it automatically disables the volume in the DAC mode. I tried again to ensure that it was not a placebo effect. I still feel the pure DAC mode sounds a little better. Changed it back to DAC.
https://yabb.jriver.com/interact/index.php?topic=99060.0 might help.