Inside a Leslie 147


This leslie was brought to me for a fairly minor amplifier problem and a checkout of the mechanical mechanisms. In the picture below the amplifier has been removed for service. The cathode biased 6550 based amplifier would sit in the lower left of the cabinet, beside the black rotating drum. The speaker portion of the cabinet consists of a 15" low frequency driver, and a horn high frequency driver, each with a method of spinning the sound into the room.

For the lower frequencies, there is a cutout in the side drum that serves as an exit point for the sound generated by the 15" downfiring speaker. The drum is attached via belts to the dual motor assembly just to the left of the speaker. There is a high speed and low speed motor, only one of which is activated at a time. Whichever motor is activated drives the belt at either a high or low speed, spinning the drum, and create the swirling sound in the room accordingly.

For the higher frequencies, a horn is mounted on a spinning wheel which is driven by belts. The horn sound is generated by a driver sitting below the horn. Only one side of the horn has an air channel for the driver, the other apparent horn is just a counterweight. The high frequency section also rotates with two separate high and low speed motors. The beauty is that the upper and lower mechanisms rotate in opposite directions which creates a moving swirling sound that has to be experienced to be appreciated.