Bright image with GC RGB cable on Super Famicom and NTSC N64

[Xan]

I've noticed that my PAL GC RGB cable yields a noticeably more garish image when used with a Super Famicom or NTSC-J N64 with the simple RGB mod when compared to a CSync NTSC SNES cable from retrogamingcables. The SNES cable has a 470 ohm resistor on the sync line, while AFAIK the GC cable has a 220µF cap and a 75 ohm resistor to ground on the CVBS line. Could that cause this difference in color levels?