Leslie, king of the rotating speaker cabinets. The RA-100 rotates two tweeters out of phase, with fixed woofers. The Leslie (122 and 147 models) has a rotating

Leslie, king of the rotating speaker cabinets. The RA-100 rotates two tweeters out of phase, with fixed woofers. The Leslie (122 and 147 models) has a rotating horn for the tweeter and a rotating baffle for the woofer. The Leslie has two speeds, and when switching speeds, the woofer baffle both speeds up and slows down more slowly than the tweeter horn, causing audible phase shifting. Ironically, while transistors for the later RA-100 are out of production, the power and preamp tubes (6550, 12AU7) for the Leslie are still available new, and the regulator can be found cheaply NOS.