This is just an idle question, asking out of interest. My Fuze V1 came with a little cable, with a data connector at 1 end and a 3.5mm stereo jack plug on the other.
With the original SanDisk firmware booted, this cable provides what seems to be a line level output. During playback, varying the volume level has no effect on the output level from the plug, which stays constant.
I had assumed that Sansa must have provided a hard wired output which bypassed the volume control function, but when trying it with Rockbox booted I find that varying the volume does vary the output level from the jack plugl.
Can anyone explain why the difference?