If they say that it is an analog bypass,it probably is just that. However, the signal still would be going through a heck of a lot of switching ICs, coupling capacitors, Op-Amps, and of course the digitally controlled volume control (which is analog, but controlled digitally).

A home theater preamp is never going to have as clean a signal path (i.e. fewer active stages, little or no solid state switching, little or no coupling capacitors)as a regular dedicated pure-analog stereo preamp.