Live, Manzerek used something called a Kee Bass (clever name, huh). It wasn't a synth bass, it was a two-octave electronic thing that sounded like a cross between organ pedals and a bad bass. But it worked. It had the strangest end panels you ever saw on either side of the white keys. They looked like the X ray glasses ads in the old comic books. Really weird. I think I removed that stuff and painted mine. The rest of it was black tolex. It had a hard cover thing that made it look like a typewriter when it was closed.
In the summer of 1969 I joined a band that didn't have a bass player, and got one of these devices. I played it with the left hand, through a bass amp, and a Hammond with the right hand through some contraption that wasn't a Leslie speaker because I couldn't afford one, but was kind of a cross between a guitar amp and a PA contraption.
We *thought* we were good. One day we opened at a festival out in the boonies somewhere in Michigan for Commander Cody and the Lost Planet Airmen. Who actually *were* good. I mean, really good. That's when I realized I had a looooong way to go.
I did get Bill Kirchen to teach me a lick when I ran into him in San Francisco a few years later. What a player!