annoying background noise on ruetz modded rat

[add4]

Hello,

So i clipped that resistor on my rat. I also changed all greenies caps by same value film caps, except for the tone cap which i changed for 3n3 instead of 2n7 and i also put a lm308 in there.

It would sound perfect if i had not an audible background noise  (whitish + some small cracks like a very small, very ugly distortion with low volume, mixed to the beautiful distorted signal)  each time i play (nothing when i don't play at all).
Does it ring a bell to anyone else who performed this mod? How could i get rid of that?

[facon]

My Ruetz modded Rat doesn't do this. I have it switchable and it doesn't make a difference for noise either way. Have you tried swapping the old chip back in?

[add4]

Hey thanks for replying and trying to help. In fact I also had an issue with the volume pot (dead) so I reflowed all joints and changed the ic and volume pot and the noise dissapeared. So I guess I'll never know what happened but it works now
I'm curious what would be the effect of increasing or decreasing the 30 of cap in terms of sound?