I"ve got a 1981 100 Watt Marshall JMP Master Volume amp that needs a little extra kick. I really love the way it sounds but I want more growl and sustain out of it. I don't want to add more buzzy/fizzy distortion. I want more growl and sustain. I would also like to retain as much of it's natural tone, punch and depth as possible. My rig is simple. I play a Gibson Les Paul into the Marshall into two Marshall 4x12 cabs. I play classic/modern hard rock ala Velvet Revolver, STP, Buck Cherry etc. I would appreciate any advice on which OD pedal would suit my needs. Thanks. By the way, I have a Tube Screamer, a Boss SD-1, and all the obvious Guitar Center pedals. Some come close (Maxon 808) but in general they add too much buzzy/fizz or squash the signal too much and I loose all the massive punch the amp has without. What do you think?