Cammy
Another alternative (for someone who already has a PC) is to use one of these inexpensive USB video grabbing devices with Virtualdub. The one I have is a kworld and it was given to me in a box of junk. I can't imagine it costing more than $40 or so new...
With Virtualdub you can set up filters and different deinterlacing options to make the screen look better. I have only played with a few of the possibilities...
I started messing it as a way to simply capture the amiga's video for youtube or something, but running full-screen I was pretty impressed with the results, enough so that I could totally see someone using that as a ScanDoubler/FlickerFixer solution.
Also, laptop can make a nice portable amiga display...
Like in your examples, Amigamaniacs SVIDEO adapter totally cleans up the picture, but the the difference between that and the built-in composite is not as dramatic. I think this device virtualdub does a really good job filtering out the noise in the composite.
I could provide some screen shots later this evening if you are interested in seeing how it looks.
_nate
