Adding a Rotary Speaker to a Hammond M-111 Organ

[stefanv]

Recently there was a thread about moving the built-in Leslie in a T-500 into an external cabinet. I've done roughly the opposite, building a Leslie-like speaker into my Hammond M-111. I've written the whole thing up, with pictures and an audio clip, on my web site at http://www.stefanv.com/electronics/hammond_rotary.html.</p>


Here's a picture to whet your interest:</p>


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[Guest]

Re: Adding a Rotary Speaker to a Hammond M-111 Organ

This rocks. Thanks for sharing it. I've beenthinking ofgrabbing the rotating baffle out of a Lowery MG and doing something similar. I don't think mywoodworking skills are nearly as good as yours, though.

[toasterDude]

Re: Adding a Rotary Speaker to a Hammond M-111 Organ



Wow - impressive work, Stefan. Thanks for sharingyour project, and especially for documenting it so thoroughly. Sounds great too - I've heard some people say they didn't much care for the animation from those Yamaha rotary units, but your sound sample makes the M111 sound like it's being played through an actual Leslie. Congrats!</P>


I actually have that exactsame rotary unit left over from an Electone E5I parted out (see my posts from a couple months ago.) I've beenthinking about making a little modular box out of it, to run guitar or combo organ through. It sounds like you took the BK20B out of service for the project - any chance you'd be willing to part with some of its components? Anyway cheers-</P>


Scott</P>

[stefanv]

Re: Adding a Rotary Speaker to a Hammond M-111 Organ

[quote user="toasterDude"]I've heard some people say they didn't much care for the animation from those Yamaha rotary units, but your sound sample makes the M111 sound like it's being played through an actual Leslie. Congrats!


...It sounds like you took the BK20B out of service for the project - any chance you'd be willing to part with some of its components?[/quote]</p>

The difference might be that the unit is rotating in the horizontal plane in my M-111, but it rotates vertically in the Yamaha organs and guitar amps.</p>

I do plan to dismantle what's left of the BK20B. I plan to keep a few parts. What parts are you after?
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[toasterDude]

Re: Adding a Rotary Speaker to a Hammond M-111 Organ

[quote user="stefanv"] The difference might be that the unit is rotating in the horizontal plane in my M-111, but it rotates vertically in the Yamaha organs and guitar amps.


[/quote]</P>


I agree - what a lot of people don't realize is that out of the twotreblehorns ina Leslie, only one of them actually has sound coming out. The other horn is just there for balance. So the Yamaha counterbalanced single speaker is actually a fair approximation of the setup. Combine that with the fact that you were careful to dial in the tremolo rotation speed, and especially that you were also careful to emulate the crossover point, and I think this may explain why your sound is so Leslie-like. I'm impressed...</P>


If you do part out the BK20B, I'd be interested in the rotary channel amp (if the organ is two-channel like the console Yamahas I've seen), and in the little rectangular grill from the side of the cabinet. Don't know if your Yamaha has this on the "rotary" side... your picture shows one side that's clearly lacking the grill, but I thought maybe if the rotary speaker was mounted on the other side they might've built a grill into that side. cheers, Scott</P>

[stefanv]

Re: Adding a Rotary Speaker to a Hammond M-111 Organ



[quote user="toasterDude"]I'd be interested in the rotary channel amp (if the organ is two-channel like the console Yamahas I've seen), and in the little rectangular grill from the side of the cabinet. Don't know if your Yamaha has this on the "rotary" side... your picture shows one side that's clearly lacking the grill, but I thought maybe if the rotary speaker was mounted on the other side they might've built a grill into that side.[/quote]</p>

Yup, I've got both. I'd already removed the amp since there wasn't anything connected to it. The grill is on the side you can't see. Contact me off-list and we can arrange something and figure out the shipping cost.
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