Two bands who have quietly become institutions - one British, the other American - and who form a mutual admiration society would seem appropriate bedfellows on this double headline bill. But the comparison, sadly, finds the Britons wanting.

It's hard to believe that Wales's Gorky's Zygotic Mynci almost had a couple of hit singles once. They have slipped from label to label, retreating into a lovely, lopsided pastoral melancholy for which there is little remuneration. Singer Euros Childs has a gorgeous voice - a soft, pillowy thing that sounds as if it is wrapped in freshly laundered cotton. And their best songs have the eerie tension of the purest folk music. However, when they attempt the garage stomp of Sweet Johnny, which is mired in the kind of gruesome indie-rock vamping the band should have grown out of years ago, they are as rock'n'roll as a school play, cursed with terminal underachievement.

In their 20-year career, New Jersey's Yo La Tengo have perfected the endless reinvention of a simple, basic format. The three remaining musicians make a little go a very long way. Occasionally Yo La Tengo are prone to experimental wittering, but this is almost a straight-ahead pop set, and they have rarely been better. Songs such as the heartbreaking Autumn Sweater and Season of the Shark turn on a sixpence both musically and emotionally. Supported by Georgia Hubley's clever, deceptively economic drumming, they use combinations of just guitar, bass and vintage keyboards; it's music that is melodically rich but full of space. They are, possibly, the Velvet Underground with gags (and minus the egos). But the most remarkable thing about Yo La Tengo is that a band of this longevity can generate such a palpable, ingenuous charm on stage. Long may they continue to do so.

· At the West Yorkshire Playhouse, Leeds, tonight. Box office: 0113 -213 7700. Then touring.