Though he’s an electrical engineer by degree, Tom O’Hanlan’s life has long been amplified by music. The owner of Sealevel Systems, a tech company he founded in 1986, O’Hanlan started playing bass guitar at 12 and has been collecting vintage instruments for more than 20 years. In 2017, he combined his knowledge of technology solutions with his passion for music in his latest venture, BookerLAB.

“I’ve always collected vintage Hammond organs and Leslie speakers [equipped with vacuum-tube amplifiers], which is what BookerLAB is focused around,” says O’Hanlan, whose collection includes 15 Leslies, three hand-wired Hammond organs, and 18 guitars—a 1955 Fender bass among them. The silver-haired rocker still plays with the members of his high school band, the Soul Sensations, who reunited a few years ago.

Designed by Don Leslie in 1941, the speaker incorporates a rotating drum. “The side of that drum would let sound out as it went around,” O’Hanlan explains. “[Leslie] hooked a motor to the drum, so when it spins around, you can hear the sound coming at you and going away from you.” This spinning creates a Doppler effect, like when a train whistle seems to go down in pitch as the train passes.

“It’s a little like a Swiss Army knife. We bring innovation, utility, and versatility to the Leslie by offering multiple types of connectors.”


A natural complement to the Hammond, the Leslie speaker made many an appearance in churches. “[The Leslie] adds depth and color to an organ’s sound,” notes Tom. In the 1960s and ’70s, it became popular with bands like Cream, The Beatles, Santana, and The Allman Brothers, who coveted its rich, swirling vibes.

Modern musicians value old Leslies, but instead of toting around heavy Hammond organs, they now use lightweight keyboards that sound similar. The problem is, they don’t interface directly with the vintage speakers. Enter O’Hanlan, who strikes a chord in the market by making new interfaces for the old speakers. “Our boxes let you hook any kind of Leslie to your system. It’s a little like a Swiss Army knife,” he says. “We bring innovation, utility, and versatility to the Leslie by offering multiple types of connectors.”

A self-described inventor, Tom shares the adventurous entrepreneurial spirit of his grandfather, Dr. Lyle Steele Booker, the late surgeon, real estate developer, and owner of the Durham Bulls, for whom BookerLAB is named. Since his childhood, O’Hanlan has always been fascinated with building. “I’ve been messing around for a few years building a miniature Leslie speaker,” the entrepreneur reports. Encased in a wooden cabinet measuring three feet tall and two feet wide, a Leslie isn’t easy to transport. “So my goal is to make one that fits in the back of your car.”

In the meantime, Tom rocks on with his contribution to the music world. “Longevity of the sound” is what he calls it. “It’s a preservation thing. It’s a love and a sharing of that music, and just making sure it doesn’t go away.”

Photography by Eli Warren