Here are some quotes by Rob Watts, who designed the mojo:
"So when you have an app that has a volume control, and no bit perfect setting, then set it to full volume on the app on the assumption that this will keep the data closer to the original file. The volume control function on Mojo is much more sophisticated than the PC as I employ noise shaping and I do the function at a very high internal sample rate. Hopefully using the volume set to max on the app will mean the volume coefficient is 1.0000000... so it will return the original data."
"If I were to use rounding then what you say is correct, there would be small signal non-linearity.
Mojo categorically does not use anything as crude as rounding to convert bit depths as the volume function is running at 16FS (705.6 kHz or 768 kHz) - I use extensive noise shaping to change bit depths. Mojo's noise shaping from beginning to end through all the intermediate paths (that is digital input to the 4e pulse array outputs) ensures 200 dB performance in band - that's better than 32 bit performance. The benefit of this is small signal non-linearity is much better, and this is essential for depth perception - the tiniest error in small signal amplitude,
no matter how small, is audible in terms of truncation of perceived depth of sound-stage.
Your assertion that analogue does not have these problems is incorrect. Any metal to metal interface contains oxides and other impurities - and copper oxide is diodic, and so attenuates small signals and creates small signal distortion. Moreover, carbon track volume controls are also non linear, as carbon composition has significant voltage dependency of resistance - another source of non-linearity. Analogue electronics additionally suffer from RF noise pick-up, which when added to an active stage will then create more noise floor modulation due to audio signal and random RF noise inter-modulation.
Mojo, unlike all other non Chord DAC's, has no measurable noise floor modulation, and zero distortion of small signals, with no measurable fundamental signal non-linearity. This is not something that other DAC's can do, nor is it something that an analogue volume control can do too. And the benefit of all this is refinement and transparency - key ingredients for musicality."
They are from the head-fi forum here:
https://www.head-fi.org/threads/cho...in-3rd-post-◄★☆.784602/page-648#post-12274209
https://www.head-fi.org/threads/cho...n-3rd-post-◄★☆.784602/page-1753#post-13030578
If you have a question about any of his products it is worth posting on the dedicated forums on head-fi. He will usually answer, and as he probably knows more about how his products are designed than most people his answers are usually worthwhile.