Ask most guitarists how to play the chord made famous by “Purple Haze,” and they’ll likely strum the E7#9 grip known informally the world over as “the Hendrix chord.”

However, other players—such as Chicago, Illinois, guitarist Paul Petraitis, who saw Jimi Hendrix perform four times in 1968—can attest that in later performances of the song, Hendrix sometimes used an open-position Em7 instead. Don’t believe him? Hit YouTube. “E7#9 is so overused in the post-Stevie Ray world, that this Em7 chord makes a nice alternative,” says Petraitis. “It doesn’t have that G#/G dissonance. It’s like the ‘Foxey Lady’ voicing.” For reporting directly from the front lines of four Hendrix concerts, Petraitis wins a Randall KH-15 Kirk Hammett practice amp!