You better believe that Ralph Tresvant felt the pressure. As the last member of the multiplatinum group New Edition to make a solo album, he watched mates Bobby Brown, Johnny Gill, and the trio of Ricky Bell, Michael Bivins, and Ronnie DeVoe (working together as Bell Biv DeVoe) all release their own million-selling projects. ''I saw Johnny on Arsenio Hall. I saw Bell Biv DeVoe up there. I was wishing that I could capture that same kind of audience,'' says Tresvant, 21. He needn't have worried. ''Sensitivity,'' his first single, soared into the top five, and his eponymous album breezed into the top 20. Tresvant's success, though, came after some hard work and frustration. He actually made one record about four years ago but, after getting sidetracked by New Edition's 1988 Heart Break album, he decided the solo effort was ''too old'' to be released. ''I wanted to show all the different sides that reflect Ralph,'' he says. To bring all of Tresvant's facets into sharp relief, seven different production teams worked on Ralph Tresvant, including Jimmy Jam and Terry Lewis, who masterminded Janet Jackson's two hit albums. On ''Sensitivity,'' Jam and Lewis have given Tresvant a sophisticated gloss, in contrast to the teenybopper bounce that made New Edition famous. In fact, Tresvant believes that today's youth-pop sensations, New Kids on the Block, need to do the same thing. ''I think New Kids have to mature with their next album,'' Tresvant says. ''They have to start gaining respect as artists instead of being a gimmick that somebody put together.'' As Tresvant knows, people get tired of the same old edition.