The Publison IM90 Infernal Machine is a sampler and effects unit used by Prince from the mid-1980s onward. It was first used during the Sign O The Times sessions, where it was used for pitch-shifting vocals. The vocals on "Bob George" from the Black Album where processed through the IM90, and it may have been used for other "Camille" tracks.
We did tons of sampling, though, even back then with the Publison, a very odd, early sampler. Prince exploited the living hell out of the Publison. It was the main tool of his work when I first joined the team.
By the late 1980s, Prince was using the IM90 as a key part of his recording workflow, using it to sample and arrange entire songs. He first used it as a sampler during the Lovesexy sessions. It was then used as a sampler extensively on the Batman album, appearing prominently on the song Batdance. It was also used for sampling bits of movie dialogue, or other instruments like the guitar on The Future.
He was still using the IM90 as late as 1999, when it was used for sampled guitar solo on The Greatest Romance Ever Been Sold (Adam & Eve Remix).
I pulled out the studio's Publison Infernal 90 and sampled and flew the parts together, creating a finished song ready for vocals. The Infernal 90 was the best thing going for digital sampling in 1990, all the flying of parts done basically by hand.
1Brown, Jake (2010) Prince 'in the Studio' 1975 - 1995