Some capture cards digitize things and do internal processing at 12bit instead of 8. However, if you allow the signal to pass through the tbc and comb filter of the player it gets sampled at 8bit before ever leaving the player. It seems like allowing the capture card to sample at 12bit would allow for the comb filter etc. in the card to make much better decisions in respect to y/c separation and denoising.

I've been pouring through schematics of the hld-x0 in the service manual. I was thinking of just ordering the parts needed to recreate the ntsc demodulation of this player since it is the best of the best. This would also allow me to simply look at the schematic as a reference whilst wiring everything together. Compiling a list of all the parts will be easy but finding them for purchase online might not be. There seems to be 2 IC's which are probably going to be hard to find. The rest is just capacitors, resistors, and transistors which are all available from ebay.