Judicious use of an octave-down pedal, not so much that you can "hear" it distinctly, but to add weight to the sound. Thin strings and very thin picks. No compression. it helps if you have a old hohner Tele Copy, although I understand prince has ALL of them.
After that I'd guess maybe a Marshall JCM 800 would get you in the ballpark, with a short delay (sub 50ms) add gobbets of reverb....