hello

I am trying to make a guitar make NES sounds when you play it.
I have an extremely rough plan that I would like to get some thoughts and advice on.
basically, i want to take whatever transmits the sound in an NES and hook it up to the amp somewhere between the input and speaker, converting the input sound into an 8-bit format.

will this work? can anyone give me a rough idea of what to do?

-thanks