/vr/ - Retro Games

I'm curious if anyone might be able to answer this;

I recently hooked up my GXTV to use for audio since my PVM only does mono(the GX has some damn good speakers, don't mind the sub either).

I use s-video from a multi-system cable for my SNES currently, but leave the composite lead hooked up anyway.

If I run that composite video to the GX, either via the PVMs composite out or directly to the GX, everything is perfectly fine. But if I leave the GX blank, or if I'm using component, such as from the Wii/PS2/etc, I get a slight jitter in the PVM's picture. This also happens if I run the component's green out to the GX to read as composite.

I guess my question is: What gives? Why is the PVM perfectly fine if the GX is getting normal composite, but running greyscale from Green or even just a blank screen bothers it?