The rise of the power trio in the 1960s was made possible in part by developments in amplifier technology that greatly enhanced the volume of the electric guitar and bass. Particularly, the popularization of the electric bass guitar defined the bottom end and filled in the gaps. Since the amplified bass could also now be louder, the rest of the band could also play at higher volumes, without fear of being unable to hear the bass. This allowed a three-person band to have the same sonic impact as a large band but left far more room for improvisation and creativity, unencumbered by the need for detailed arrangements. As with the organ trio, a 1960s-era soul jazz group centered on the amplified Hammond organ, a three-piece group could fill a large bar or club with a big sound for a much lower price than a large rock and roll band. A power trio, at least in its blues rock incarnation, is also generally held to have developed out of Chicago-style blues bands such as Muddy Waters‘ trio.
In addition to technological improvements, another impetus for the rise of the power trio was the virtuosity of guitarists such as Eric Clapton, Jimi Hendrix, and Rory Gallagher, who could essentially cover both the rhythm guitar and lead guitar roles in a live performance. In 1964, Frank Zappa played guitar in a power trio the Muthers, with Paul Woods on bass and Les Papp on drums. In 1966, the prototypical blues-rock power trio Cream was formed, consisting of Eric Clapton on guitar/vocals, Jack Bruce on bass/vocals, and Ginger Baker on drums. Other influential 1960s-era blues rock/hard rock power trio bands were the Jimi Hendrix Experience, Blue Cheer, Grand Funk Railroad,[ the James Gang featuring Joe Walsh, and Taste.[
Well-known 1970s-era power trios include the Canadian progressive rock groups Rush and Triumph, the American band ZZ Top, the British heavy metal band Motörhead, and Robin Trower. English progressive rock band Emerson, Lake & Palmer replaced the guitarist with keyboardist Keith Emerson who fulfilled the rhythm and lead playing on the keyboards, while bassist (and occasional guitarist) Greg Lake was the vocalist.
Here is my Apple Music “Three Piece Wonders” playlist