Fair 'nuff on the red book CD rips.
Interestingly, all of the Squeezebox family convert 16 bit to 24 bit for the digital volume control to work.
And it is implemented upstream of the digital outputs too.
So 16/44.1 wavs/flacs are always played back as 24/44.1 .
Even more interestingly is that when you compare a true 24/44.1 (HDCD content ripped with dbPoweramp) file against a 16/44.1 converted to 24/44.1, the superiority of the true 24/44.1 file is all too readily apparent. Just so long as you don't allow yourself to be fooled into thinking that the louder ('cos it is by 6dB) 16/44.1 files has more detail initially.
Chris