PS NTSC/UC SCPH-7501 with better video (Vivid Colors) How to spot one?

I think you should do as we have suggested several times over and get a different TV with S-video input instead. You will never get anything close to a decent picture using composite regardless of video encoder.

 

At the very end of the day, there was a reason why people stopped using composite and moved onto using newer standards like component and RGB. So unless you love the idea that some PlayStation games were perhaps meant to look best with composite video, it is not easy to get the perfect setup from what I understand: Sony eventually went into cost-cutting mode, which reduced the quality of the design, which in turn "worsened" the quality of composite video output in general.

It is possible that Sony did manufacture a few revisions of a model, under the same model number. The same mainboard may even be reused over a few models. Some may have been conceived to bleed their stock of parts dry, whenever they moved on to newer designs. This may explain why you don't find any particular pattern in functionality, across all the consoles that you have acquired so far.

 

I hate this comparison as the composite filter on the emulator looks nothing like real composite, theres no rainbow effect on edges and transparency effects that composite causes, do not look that good in reality.

 

Change your TV then