I just got my Pronto yesterday. Yea!

I have a similar problem to what Dave describes above. My PreAmp can't mix S-Video and composite.

As suggested above I tried a Tributaries C2S cable last year, but I got unacceptable chroma smearing from the VHS playback. So I went back to using the TV as the video source switcher.

I have previously been using a Marantz RC2000 MKI (which has a plenty of room for improvement) and had programmed some macros like those above to deterministically set the TV's video input selection. This works ok except it's a little slow and there's some video flashing when switching to the TV tuner and then away to another source.

Now I've got a two S-Video sources and my TV only has one S-Video input. So I've got to rethink the problem. Hopefully the Proto's additional flexibility will give me some new options for making this stuff act like it all works together.