peavey heritage vtx help!

[juanpapino]

hi i need help to mod this amp .
clean chanel is not clean at all .. as more volume you add more distortion you get .. also got a lot a ground noise...this is the schematic.
http://www.schematicheaven.com/newamps/peavey_heritage_vtx.pdf

i'm a nubi please try to be specific with location ...for mod ..
thanx so much ...my regards..
pablo..
can email me to pablo_juan@sbcglobal.net