The denon 2805 has video up conversion? Does it work? Thinking of running my cable box through then to tv. Anyone help?

Tom, yes the 2805 has video "upconversion" and it works, but understand that it can't increase the quality of an input that's composite or S-video; it just allows all those video inputs to be sent to the TV over the component connections.

So signal from cable box cannot be up converted unless coaxial
or component used?

It depends on what type of signal is now coming out of the cable box. The point of the "upconversion" again is to allow several video sources which might come in different ways, e.g. composite video, S-video, component video, to be connected to the TV with one set of component cables, instead of requiring separate composite, S-video and component connections.

Thanks for the info! Cannot decide if will be worth the trouble. Trying to improve this shitty cable signal we get here. The wife still likes the tv audio for her nightly
channel surf. So might leave well enough alone and wait for the fall and get HD sat system. Once again thank-you for the help.

The others are correct, it is a nice way to reduce the number of cables you have going to your tv/projector. It does not upconvert/improve the quality, not to be confused with upconverting DVD players, as they do take a 480p DVD and upconvert it to 720p/1080i, basically near HD quality