Whats with the SNES hum over RGB/Scart cable?

So today I've build a cable using 9 different wires.
All shielded, all individually bought.

The result using the 220 uF / 25v caps + 75 ohm resistors on the R G B line and the result was a very dark picture.
I've tried without the caps resistors and it still get me a dark picture.







I'm using this diagram:

 

Was the cause of this ever found? I just recently got this amazing amp (sansui G-7500) & decided to feed my SNES through it & the buzzing noise I get in the back is really killing the experience for me. Maybe wookiewin on eBay would have an answer since he builds these.

Thoughts?