Hey guys. I’m pretty inexperienced when it comes to electrical engineering; however, I am dying to get a pet project of mine off the ground.

About 3 years ago I bought a Hammond L-100 organ for $70 off of OfferUp. I am about to move and don't have enough room for the organ and couldn’t sell it.

To fans of antiques, I am sorry: I came up with the idea to disassemble it so I could use the internal Leslie rotary speaker as a guitar amp (my main instrument). I plan on eventually packaging everything as a full, neat speaker box.

At this point I have taken out the Leslie speaker, motor, and rotation unit but I’m honestly kind of stumped on my next course of action.

The speaker itself is mounted to a piece of plywood, but I already unscrewed both the motor and rotation unit from the mount.

My plan was to solder the speaker wires onto a 0.25” jack that I would integrate into the final rotary speaker box. I would then run my guitar through a preamp which would output to this new speaker box, producing a sound output. <would this work?>

Now the hard part: I extracted the original rotary speaker motor from the organ, which contains a 5-wire power jack that connected to another part of the organ (pictured… 2 of the power cables connected directly to the speaker but I already cut them off. I have never messed with motors before, so I have no idea why it has 3 wires, how to provide a stable voltage, or how I could power it directly from a common AC outlet. The side of the motor has a bunch of numbers as well as “115 volts”.

So here is my question: if I have everything else right, how can I power this motor from my wall, and can I create a circuit that would allow me to alter the motor’s speed (either with a button or pot)?

Thanks for your help.

 

So here is my question: if I have everything else right, how can I power this motor from my wall, and can I create a circuit that would allow me to alter the motor’s speed (either with a button or pot)?

From what little I know about a Leslie speaker they only rotate at the one speed. That speed was the one that gave the correct amount of artificial reverb in the average room size. To do it with a speed control you will need to change the motor to one that uses DC and use a speed control for a DC motor. Single phase 115V AC induction motor speed control is not easily or cheaply done.

 

As far as I know all Leslie style Speakers are Variable-Speed,
and are controlled with a Foot-Pedal.

Notice that the Motor uses 4-Wires............, and none of them are Grounds .............,
just don't ask me about the funky Tube-Speed-Controller-Circuit they used for controlling the Speed.

If a proper Schematic can be obtained,
there might be a chance of re-using the original Motor,
otherwise, changing to a new DC-Motor and DC-Controller will be required.

Having a genuine Leslie-Cabinet might give You some "Cool-Points",
but an even better effect can be reproduced with a high-quality pair of Stereo-Speakers
powered by a Pawn-Shop ~35-Watt Stereo-Receiver,
and using a Laptop-Computer for a Guitar-Interface and Effects-Source.
There are some absolutely astounding Guitar-Software-Effects-Programs available
which don't limit You to just 1-type of Sound,
and they are much easier to learn than trying to buy 15 or 20 "Instant-Rock-Star" Effects-Pedals
and figuring out how to organize and adjust them into something that's actually respectable.
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