David worked as Road Manager for the Steve Miller Band, one of the biggest names in rock and blues – and became an official band member in 1970 with Steve Miller, Ross Valory, Bobby Winkleman, and Jack King (line-up in 1970).

“Rock Love is a half live / half (sixth) studio album by American rock band Steve Miller Band. The album was released in September 1971, and compiled by Capitol Records. All of Miller's previous backing band had left following the recording of the previous album, save bassist Bobby Winkelman. They were replaced by members of Winkelman's previous group, the psychedelic rock band Frumious Bandersnatch for this record, including Ross Valory (a future member of Journey) on bass, and Jack King on drums. Bobby Winkelman was in the band (having moved back to rhythm guitar) during the live recordings on the album's first side, but is not credited on the album cover. David Denny, who later joined the band in 1976, is a guest guitarist (not credited) on "Blues Without Blame". – from Wikipedia (https://en.wikipedia.org/wiki/Rock_Love)