All musicals are time machines. The classics take us back to the golden age when they were composed, but they and others also take us back to the times they dramatize. Even musicals set in our own day take their self-conscious place in a tradition, reviving the youthful wonder musicals once stirred.

But strictly speaking, "Smokey Joe's Cafe," a revue of popular songs by the fecund team of Jerry Leiber and Mike Stoller, now playing at Pittsburgh CLO, isn't really a musical at all. A singing ensemble of eight and an onstage band of seven perform some 39 songs, plus a number of reprises, without any more attempt at narrative continuity than to let one song speak to the next.

So it's not a jukebox, catalog or song book musical as we've come to understand those terms, in which a composer's output is ransacked for songs that are strung together with some kind of plot. It's a golden oldies revue.

But it's still a time machine, perhaps even more so. Who can listen to these classic rock tunes from the '50s, '60s and '70s without being taken back to what seems in retrospect a simpler, wittier, more joyous musical time?

Or maybe I'm just committing the critical fallacy of making my personal taste into a standard. If so, it's a standard familiar to many in the CLO audience, where white hair is right at home. They say the great pop music is always the music of your youth, and I wasn't the only one at Tuesday's opening who was experiencing remembered pleasures.

Of course, wiping away the years is a chief pleasure of all musicals, stirring the tunes in our hearts and the rhythm in our feet. Surely that happens with younger audiences, too, as the ubiquity of high school musicals suggests.

In fact the only objection I can imagine to finding "Smokey Joe" on the CLO schedule is that it isn't really what the CLO exists to produce. But "Annie Get Your Gun" and "West Side Story" lie just ahead. So this week we can kick back and enjoy the simpler pleasures of a cornucopia of classic pop, its songs connected only by the chameleon-like talents of their composers and by the individual performers' charm and skill.

Leiber and Stoller's facility in different modes -- they wrote for Big Mama Thornton, Elvis, Peggy Lee, The Coasters, you name it -- might raise suspicions among those who prefer their art more "authentic," but they created songs that can sustain very different interpretations, which is one measure of art. I'm sure many in the audience hardly recognized "Hound Dog" as (here) a woman dissing an unreliable man.

Occasionally, though not as often as I would wish, the individual songs link up to create a crescendo, as in the dynamite trio ("Baby, That Is Rock & Roll," "Yakety Yak" and "Charlie Brown") at the start of Act 2. But mainly, it's the individual talents that score. Act 2 is more electric, but that's partly because we've sorted out the performers by then and learned to respond to their strengths.

It's hard to pick favorites, but Clifton Oliver shows the most variety, and cute Debra Walton scores as the sexy, funny tease (watching her manipulate the world's longest feather boa is a hoot). Classy Terry Burrell has a voice that keeps on giving and chunky Harrison White fronts a dynamite Act 2 sequence of "There Goes My Baby" and "Love Potion No. 9."

Renee Feder is the blond songbird who gets to do the shimmy in a dress that's positively alive and Phillip Boykin has a rich bass voice that's used to good comic effect. Bob Gaynor shows some Elvis-like moves. Supple Kevyn Morrow and Debra Walton join nicely on "Spanish Harlem." She doesn't quite get everything out of "Pearl's a Singer," but it's still the fullest little drama of the evening.

Craig Barna leads a musical combo that is a full partner, not just backup. Barry Ivan directs and choreographs, the former consisting mainly of the latter, since moving around the skeletal set of platforms and stairs is the main action. He uses a lot of classic doo-wop group moves.

As I understand, Leiber and Stoller are now both 78. Their music is a lot younger than that and shows no sign of aging at all.