Jack Bruce, who became famous in the 1960s as the bassist and lead vocalist for the hugely successful rock group Cream, and whose adventurous approach to his instrument influenced two generations of rock bassists, died on Saturday at his home in Suffolk, England. He was 71.

His family announced the death on his website. A spokesman said the cause was liver disease; Mr. Bruce had received a liver transplant several years ago.

Mr. Bruce was well known in British rock and blues circles but virtually unknown in the United States when he teamed with the guitarist Eric Clapton and the drummer Ginger Baker to form Cream in 1966.

One of the first of the so-called power trios — the Jimi Hendrix Experience soon followed in its wake — Cream had its roots in the blues and became known for Mr. Clapton’s long, virtuosic solos on reworked versions of blues standards like “Crossroads” and “Spoonful.”