Mike Gibbins, Welsh drummer with Badfinger, the first band signed by the Beatles' Apple Records, has died at 56.
Mike Gibbins: creative and multi-talented, says Badfinger biographer
Gibbins was a mainstay of the group formed in Swansea in the 1960s whose song Without You was a major hit for both Harry Nilsson and Mariah Carey.
But Badfinger had a tragic history, and both main songwriters Pete Ham and Tom Evans hanged themselves amid turmoil in the group's finances.
Gibbins died in his sleep at his Florida home on Tuesday.
His official website says: "To all of Mike's fans, it is with deepest regret to inform all that he passed away 4 October, in his sleep by natural causes. He will be terribly missed by all."
Badfinger signed to Apple in 1969 and their first single, a Paul McCartney song, Come and Get It, reached the top five.
They retained close links with the Beatles, with George Harrison co-producing one of their albums, Straight Up, and guitarist Joey Molland and bassist Tom Evans playing on John Lennon's Imagine.
Nilsson's version of Without You, written by Evans and fellow guitarist Pete Ham, went to number one in 1972, as did Mariah Carey's in 1990.
But despite more of their own hits Badfinger's career went sour over finances. They signed to Warner Bros, but their third album for the label was never released and in 1975 their contract was ended.
Badfinger at their peak, with Mike Gibbins third from left
In April 1975 Pete Ham hanged himself, aged 31. The band continued amid financial and legal problems, but seven years later Tom Evans also hanged himself.
Gibbins continued in the music industry, and played on such tracks as fellow Swansea artist Bonnie Tyler's 1976 hit It's a Heartache.
He lived in the United States for many years, but Dan Matovina, who wrote the biography Without You: The Tragic Story of Badfinger, said while Gibbins was happy-go-lucky, he also found it difficult to come to terms with the deaths.
"Badfinger was the highlight of his life, coming out of Wales, having success, touring America," Matovina told the BBC News website from California.
"But the tragedy of the loss of two of his bandmates to suicides weighed heavily on that.
"A lot of things happened that were difficult for him to deal with, the loss of Pete Ham especially, his close friend from Wales - I don't think he ever got over that."
Keith James, who edited the band fanzine Badfinger File, said Ringo Starr was an admirer of Gibbins, adding: "I think he was one of the great rock drummers."
But James said fans resented the emphasis on the band's troubled story, and preferred to concentrate on their outstanding music.
"Mike got nothing like the money he should have done, but he was quick to blame it on the band's naivety," said James.
"He said once, 'What the big print giveth, the small print taketh away'."
Matovina described Gibbins as self-deprecating and quick-witted, and a creative and talented multi-instrumentalist who was under-estimated.
"He was very nice, but he wasn't aggressive to push his own material."
The biographer said money was eventually released to band members and their families, but it took years of legal action.
Gibbins, whose former wife Gaynor still lives in Swansea, also leaves three sons.
His family received friends at a funeral home in Oviedo, Florida, on Friday, where a service of remembrance will be held on Saturday.
Matovina said a service would also be held in Wales, where Gibbins has a very close extended family.