The nut on the input jack is loose, and my wrench can't fit to tighten it...what should I do? And just using a wrench won't break any of the electronics right? I screwed up my volume knob by just trying to tighten it with a wrench..

Tightening the input Jack
1) Open up the input jack's plate, do not tighten it from the outside coz it will twist and snap the connection inside.
2) Insert the jack, see whether the connection is proper, then only you tighten it. Make sure that the shield and tip connects to the hot (red). Also, tighten it properly so that you dont have to do it again. Always good to use plumber's tape if its loose.
3) Test out which wires go where by tuning ur amp on if you're not sure. Resolder the connection.
4) Screw back the plate.
"Play with your ears" - Yngwie Malmsteen, Paul Gilbert
Thats what she said...