I think The Stooges were the quintessential one-head band. The Stooges boys dicked around with various instruments before they found the instrument of their calling. It no doubt helped that they all knew each other. It also helped that they had over a year to play together before any recordings were made. But this alone cannot explain the magic they made. After 2 classic albums they fired the bass player, replaced him with an 18 year old and added a second guitarist. Still a one-head band. Then they demoted their original guitarist to bass, with the new guitarist taking his place. The resulting album Raw Power was arguably their best ever. The decision was made that they needed to supplement their sound. A piano player who had played with Iggy in the Prime Movers was coaxed by James Williamson to join the band. A risky move. Still a one-head band? Indeed. I think the band's music swung like never before.