So when the Cardiff band split in 2001 - singer Cerys Matthews was being treated for anxiety and exhaustion - it was time to build a new career.
Five years on, Powell has found himself back in the classroom, studying a course run by the Welsh Music Foundation, a not-for-profit organisation that supports the nation's music industry.
The course, accredited by the North East Wales Institute in Wrexham, is a unique programme that will help him make the most of his new business: composing for film and television and managing up-and-coming bands. Fellow students include a band manager and the head of an independent record label.
"I always had trouble staying in college because I was off playing gigs in bands. All I ever wanted to do from the age of 14 was to be in a band,"
"I got to live the life. I was never any good at football, but I got to do the one other thing that I loved doing. But when the band ended, I had to learn to hustle to get by as a professional musician.
"Having spent five years in the real world of dealing with the music industry, I realise that a lot of my experience has been got through making mistakes. What I wanted was information so that, rather than learning from mistakes, I wasn't making as many."
The part-time, six-month programme is taught by experienced people from the Music Managers Forum, the professional body. It covers such subjects as contracts, budgeting and the new world of digital music distribution.
"Being a musician, you don't just need to learn about playing music, you need to learn about recording, marketing and promotion, the legal side of things. You learn it by osmosis. Nobody gives you a manual," said Powell.
"The more successful you become, the more people you employ to look after the business side of things. First, it's a manager, then a lawyer, a press officer and a publicist.
"One thing I could say, looking back, is the more you can learn about these things yourself, the safer you are and the less you will feel the fall when it all comes apart. A little knowledge can't be as dangerous as knowing nothing."
Allowing musicians to learn more about the business side of the record industry will also help them survive in a world where record sales are falling, said Powell. "The tradition is that you sign on with a big record company and they do everything for you. But there are fewer and fewer people getting rich from that, and more and more people making a living out of having their own control."
But musicians will have to overcome their resistance to the habit of studying. "It's actually very un-rock and roll," Powell said.
"When I was in a band, I was increasingly mistrustful of people who spoke the language I now have to speak every day. But it's allowed me to carry on making a living out of music, which is really the only thing I can do, rather than going to work in a call centre.
"I've just started the course. What's really terrifying is I haven't even considered the prospect of doing exams. My life is flashing before my eyes."