Do I need a scaler?

[blownrx7]

I have a Denon DVD-5900 that upconverts to 1080i (I think) and I am using it with a Sanyo PLV-Z5 projector. Is there any advantage to buying an outboard scaler? Which one? DVDO seems to be the most prevalent but are there others to consider?
Also, I purchased the Denon used and the previous owner installed an SDI output card. The only way to utilize it is with a sclaer that has SDI input. Again, is it worth the expense. Will I see significant picture improvement?
TIA

[Dougie085]

Do you have other sources that need to be scaled? The best reason to get a scaler is that the outboard scaler does a much better job of scaleing the image then the internal scaler on your projector or dvd player or other sources. The DVDO units are some of the better units and often are much better then onboard scalers.

[blownrx7]

Well, in that setup, there is only the vcr. Can that be scaled?
That and the DVD-5900 are the only two sources I'm using. I plan on getting an OTA HDTV tuner (when I find one but that's another story), but that would already be 1080i, right? Could it scale SD programming as well and is it worthwile to do so?
Oh, and what about standard catv (no cable box) too?
Sorry for so many questions but I am just beginning to step into the HD world and have a lot to learn

[brucek]

I think a scaler is needed when you have a bunch of different sources with different resolutions and cable types that can be connected and switched by the scaler and then converted to a single common native mode of the projector using a single cable for the long run.

Yes, anything can be scaled, but it ain't magic. A VCR (480i NTSC) will not all of a sudden look great because it's scaled. There's no new information. The better the scaler, the better the result. There are lots of $10,000 scalers and then there are scalers much cheaper......

brucek

[blownrx7]

A VCR (480i NTSC) will not all of a sudden look great because it's scaled. There's no new information. The better the scaler, the better the result

Well, I guess that's what I'm trying to figure out without taking the plunge first.
I indeed have different resolution sources. Will the vcr 480i actually look SIGNIFICANTLY better scaled up or just passed thru to the projector.
Also, will my Denon do any better through the SDI output to make it worth the expense of an SDI input on the scaler?

As far as DVDO, Given my inputs (DVD, VCR, SDTV (cable) and OTA HDTV, which one to get? The VP20, 30 or 50???
Lastly, has anyone used scalers and NOT been happy with the result?
TIA