Homebrew Leslie....

Discussion in 'Shock Brother's DIY Amps' started by RottenTheCat, Sep 15, 2019.

  1. RottenTheCat

    RottenTheCat Tele-Holic

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    When I was in probably, on rusty memory, grade 8 in school, I pronounced to a keyboard player, a certain Mr. Brian G, that I wanted to build a Leslie - after trying his out with my guitar. Brian is my age, and pronounced back... "You can't build a Leslie!", as if there was either some magic involved, or my skill-set didn't impress him all that much. Fast forward and I'm approaching grade 70, and I think its high time I proved that little bastard wrong.

    I've seen several, mostly well written articles on "DIY rotary speakers", with some being a little dubious on long term reliability. Grade 11 science teacher, a chemist named Charles B, instructed that the best teacher is someone else's mistakes (as he poured some slow acting future stink bomb into a beaker). I tend to agree.

    I can sort out the details on how to build a proper rotary drum, how it must be supported axially via bearing and motor.... all of that is good.

    What I'm totally devoid of is how to select a QUIET low speed variable motor. What comes to mind at first, is to go buy some old, non-collectable sewing machine and strip the motor out of it. Certainly, more elegant solutions exist.

    If you want a gear motor to spin a polishing drum, or a motor to run a conveyor, or worm drive for a lift, I've got that. Big power, 10x the torque, and damn the racket, its gonna work.

    Matters of motor delicacy have never crossed my path..... and so I enlist my comrades here for some schoolin'. Please!

    I get this reverberator finished, next thing out the gate is a Leslie
     
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  2. RollingBender

    RollingBender Tele-Afflicted Vendor Member

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  3. Syrinx

    Syrinx Tele-Meister

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    I built one back in the day with a ceiling fan motor- three speeds already!
     
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  4. kingofdogs1950

    kingofdogs1950 Tele-Holic

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    I had a home made Leslie back in the day, uh, 1968. I played combo organ in a cover band. We decided that a Leslie sound would be coolio so a band mate and his dad built the home brew Leslie. I was not involved in the construction and don't know how it was built. It worked very well but I really don't have anything for comparison as I've never used a real Leslie.
    It made my Vox Jaguar organ sound a lot better.
    I wonder whatever happened to that homemade Leslie?
    Actually, it occurs to me that the same guys also made copies of tuck and roll Kustom cabs that were nearly indistinguishable from the factory cabs. The dad I mentioned owned a furniture repair and re-upholstery shop. There are several of the fake, but as good a factory, Kustom cabs somewhere in Texas.

    Mark
     
  5. moosie

    moosie Doctor of Teleocity Ad Free Member

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    Grade 70.... :lol::lol::lol:


    Good luck with your project. Er, I didn't mean luck, certainly you won't need that... :rolleyes:
     
  6. moosie

    moosie Doctor of Teleocity Ad Free Member

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    Are you really making a reverberator? As in a Revibe? I think Mark Baier (Victoria Amps) calls his the Reverberator. Or are you 'just' building an outboard reverb?

    I built a Revibe a year or two ago, and it's almost as sweet as a Leslie! :twisted:
     
  7. RLee77

    RLee77 Friend of Leo's

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    Ceiling fan sounds perfect.
     
  8. magic smoke

    magic smoke Tele-Meister

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    +1 on the ceiling fan motor. Have you considered using a motor from an unwanted turntable ? I have a couple of Leslie’s pulled from old organs, let me know if you want some pics of the assemblies.
     
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  9. Rev Rhythm

    Rev Rhythm Tele-Meister

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    I almost suggested a turntable motor but wasn't sure if it was strong enough. Certainly quiet though.
     
  10. RollingBender

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    Tried that once...not enough horse power.
     
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  11. Rev Rhythm

    Rev Rhythm Tele-Meister

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    Kinda assumed as much. Turning a platter is one thing.... Turning a whole speaker is something else entirely.
     
  12. schmee

    schmee Poster Extraordinaire

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    Well, I guess what you want is a DC motor so it's easy to have the variable speed. But vari speed AC are out there too. It would be big but I suspect the super cheap ceiling fan motor would be quiet, slow enough and variable. But Check Ebay for cheap DC motors. There are 49,000 of them there today.

    The rotor would be tricky but the design is probably pretty forgiving. Last one I did I took out of a Baldwin organ. It had the small rotor and motor etc built right in the organ. It worked fine and wasn't any bigger than about a cubic foot or so.
     
    Last edited: Sep 16, 2019
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  13. RottenTheCat

    RottenTheCat Tele-Holic

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    Yes, grade 70... and I'm still kickin'! Ceiling fan motor has no torque at low speed. You needa start 'em at higher speed, then throttle down.

    I think Leslie had the best approach with a belt driven motor(s). With belt drive you need an idler to keep tension. But, you get to relay on/off the motors with a foot switch.

    The important things: Keeping the mechanism facing forward in "off" position, and smooth transition to high and low speeds.

    Please refer to "Give Me Strength" from "461 Ocean Blvd". Listen to Dick Sims work on the Leslie... it amounts to a separate instrument in its own right. That's the best Leslie switching I've ever encountered.
     
  14. RLee77

    RLee77 Friend of Leo's

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    My understanding is that original leslie units have a measurable, not-rapid spin-up and slow-down time. Whatever you use, you don’t want it to instantly get to full speed, if you want to emulate the real thing.
     
  15. RottenTheCat

    RottenTheCat Tele-Holic

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    Tru dat if you pay attention to the spin top speed you'll see that it's working against some weight aka the drum. Ditto thedown speed there is inertia from the drum. My guess is a 600 RPM motor and belt would be the best way to go for single speed.
     
  16. Wally

    Wally Telefied Ad Free Member

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    I have a Baldwin Leslie cab. It came to me with no amp, and that is fine by me. The cab is lighter than most Leslie’s, and the lack of the an amp decreases the weight even more. I heart to have a variable speed control and have tried a sewing machine footpedal for that purpose. It worked, but it did heat up a bit so I have not hardwired it in. Has anyone taken this approach. If so, what amperage capability are we looking for in such a foot control? I suppose I need to know the particulars of whatever motor was in the sewing machine, right?
    I also have an identical rotor assembly that came to me without a cab.i need to get busy and build one for that assembly. I like to run a Leslie in conjunction with an amp with tremolo...magic.
     
  17. Syrinx

    Syrinx Tele-Meister

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    I have a Leslie 520 that the amp is pulled out on so I can use my guitar amps to drive it. Just have a switch for fast and slow. Since the motor is always on when plugged in- it is easy to forget it is on when on slow-so i made a power footswitch for it that also turns on two or those "fire"LED bulbs. I call it my Flaming Leslie-has caused more than one dropped beat when I kick it on!
     
  18. RottenTheCat

    RottenTheCat Tele-Holic

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    Trying to work out a "drum position" stop point.
     
  19. RottenTheCat

    RottenTheCat Tele-Holic

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    Leslie update: This is all in the planning stages of course, but I've been able to work out a wiring schematic and a 4 switch "pedal" for the unit.

    My idea so far... One drum, with high and low speed motors. Run about 1rpm and about 10rpm.

    The foot pedal will be momentary buttons for Start and Stop. Those run the low speed relay. A reed switch and magnet will control facing the drum opening forward when it stops. Doesn't have to be perfect, just mostly so. My arrangement will be adjustable to compensate for wear and such.
    The next two switches are "High Speed", with one being "constant" and one being momentary. Those are in parallel, but... only engage the high speed relay, who's power is run through a contact on the low speed relay. IOW, you have to have low, in order to have high. Low shuts off, so does high. You have to re-start low to have high again.

    One quirk, but I don't think its a deal breaker. That is - to keep it simple, you have to hit the stop button until it stops. If you don't then you'll be one more revolution. The motors have indicator lights in parallel, so you can see that on the foot switch, and when the light goes out (less than 1 second) you can take your foot off the stop switch. Start doesn't matter.

    Another item, is the momentary for high speed, so you can ride the motor a bit and ramp it some, then let it come back down.

    Refer to Dick Sims excellent use of the Leslie (for organ) on most of the Clapton stuff he did, especially Give me Strength, which I think was on 461 Ocean Blvd (from memory). He rides the high speed switch perfectly, and I'm suspecting he had a modified setup to do that, maybe with a knee paddle?
     
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  20. RottenTheCat

    RottenTheCat Tele-Holic

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    And in my haste.... I meant RPS not RPM....

    Come to find out that the stock units did about 1rps in slow, and about 8 rps in high... numbers being a bit variable, but about an 1:8 speed change, with the drum taking longer to ramp up to speed, and more time to come down to speed, due to inertia
     
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