Does a turntable make a DRAMATIC difference?

I purchased some analog gear in the hopes of making my analog side (a Sutherland 20 20 phono preamplifier and a Hana ML cartridge) at least the equal of my digital side. Although it has markedly improved the sound of my records it has not equaled the SQ of my digital sources. I know my turntable ( a heavily modified Rega RP3 with two power supplies and many other internal tweaks) is the weakest link. My question is, will a new improved turntable make a MAJOR difference, or just incrementally improve the sound. Or do I have to spend major bucks to achieve what I want.