“That was it,” he added. “It was like the plug was pulled, ‘No money for you anymore.’ ”

But he was still under contract, he said, and extricating himself took four years. Around 2000 he started talking with the band members about restarting My Bloody Valentine, but they were all involved in other projects. Years drifted by.

In 2006 Mr. Shields started remastering the My Bloody Valentine catalog and revisiting unreleased songs to be added to a compilation album. When he listened again to material from the aborted third album, he was heartened. “I realized that all that stuff I was doing in 1996 and 1997 was a lot better than I thought.” He now plans to complete that album, and to start recording new material with the band in the fall. He has been writing songs steadily over the years. “I definitely don’t think you need to suffer to be creative,” he said. “I’ve written some of my best songs when I’ve been happy.”

During the remastering the Coachella Valley Music and Arts Festival in California made a big offer for a reunited My Bloody Valentine. “We could actually buy equipment and rehearse properly and do it really well,” Mr. Shields said. “That put the idea into our head. Last time we toured we never had equipment. It didn’t sound right. We didn’t have control of the environment. So we were kind of excited to play the songs properly.”

But the band wasn’t ready to appear at the Coachella festival in April, Mr. Shields said. All Tomorrow’s Parties had been courting Mr. Shields for years, and having attended its festivals in Britain, Mr. Shields decided to bring My Bloody Valentine to the upstate New York festival. “We had intentions to do new stuff when we started rehearsing,” he said. “But it was about finding who we were again, and that became way more important than anything intellectual.”

The band spent £200,000, about $366,000, on equipment for the tour, and Mr. Shields laughed when asked how many effects pedals he owned. “Hundreds,” he said. He only uses 30 onstage, he added.

There were no new songs in My Bloody Valentine’s set on Sunday, but as in the ’80s and early 1990s, My Bloody Valentine’s music flashed simultaneous, contradictory signals: the songs were bruised and hurting at their core but exultantly propulsive, catchy like punk and pop but spiked with fearsome cacophony. High, looping sounds skirled like Celtic reels; guitar chords hurtled forward, heaved back and forth, screeched with fury and exaltation; the drums were triumphal and implacable. “You can’t do anything with sound,” Mr. Shields had said, “unless there is emotion.”