Here´s a free Kemper Profile of a Marshall JMP Lead, boosted with a Marshall Drivemaster. Gary Moore used a Marshall Combo and an old Marshall Guv´nor Pedal. The old “Drivemaster” is probably the same circuit as the “Guv´nor” without the inbuilt loop and still inexpensive.
This is a great example of how you could “mod” your amp with a pedal.