Goldy McJohn, a founding member of Steppenwolf and the keyboardist who powered some of the band's best songs, has died at age 72.

The news was confirmed on his Facebook page, which reports that "Goldy suffered a sudden and fatal heart attack the morning of August 1st, 2017."

McJohn helped form Steppenwolf in late 1967 in Toronto along with singer John Kay and drummer Jerry Edmonton after they split from Jack London & the Sparrows, which also included Bruce Palmer, who later joined Buffalo Springfield. Earlier McJohn was a member of the Mynah Birds with Palmer and future R&B star Rick James. Neil Young (who also joined Buffalo Springfield) was a member of that band after McJohn left.

The keyboardist found his biggest success with Steppenwolf, whose self-titled debut album from 1968 included the hits "Born to Be Wild" (which reached No. 2) and "The Pusher," both which featured McJohn's heavy Hammon B3 organ fills. He's often credited as a pioneer in the instrument's prominent use in metal and hard rock.

McJohn played on six more albums with Steppenwolf, including 1968's The Second, which highlighted another Top 5 single, "Magic Carpet Ride," and again featured his soaring organ. His last album with band, 1974's Slow Flux, was followed by his termination from the group by leader Kay.

Over the years, McJohn also played with a band called Manbeast, which he formed with Steppenwolf drummer Edmonton when that group was on a break in the early '70s, a later version of Humble Pie with Steve Marriott and with a revamped Steppenwolf that didn't include Kay.

He later moved to Washington with his wife, Sonja, and released a series of solo albums and led bands with Steppenwolf-referenced names like Born to Be Wild and Magic Carpet Ride. According to the Facebook post, McJohn was actively involved in a project called Stand Up for the Music, which had announced a new charity event just hours before his death.

“I was devastated," noted Anthony Spadaro, who's referred to as a managing partner. "We all are still devastated, but I know in my heart, as does Sonja, that this concert must go on. Goldy would want us to do this. As Goldy would say, 'It's showtime.'"

Steppenwolf were nominated for Rock and Roll Hall of Fame induction this past year, but didn't make the cut.

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