Fender Vibratone

[woodyc]

I'm building something similar to a Vibratone, using a Leslie from an old organ (maybe a Wurlitzer?)

I was thinking about just directly switching the motors with a footswitch - no supply, no relay.

Anybody have an opinion on that?

(The fast motor pulls less than 1/2 amp, the slow motor even less.)

[52 Bill]

Anybody have an opinion on that?

(The fast motor pulls less than 1/2 amp, the slow motor even less.)

I'm not a fan of running live 120v ac lines to a footswitch, but it can be done. It doesn't matter how much current the motors draw, the cables will supply as much current as the wall outlet will carry.

What sort of box will the switches be installed in? I'd suggest metal case, grounded to the power ground.

[J M Fahey]

I *might* use a 120V footswitch to turn on/off a machine motor, at a shop, just at the feet of the machine, such as to leave my hands free to work.
I would *NOT* run a long live power cable to a footswitch on stage, Friday or Saturday night, full of stomping drunk people in the dark.

[Enzo]

I agree. It isn't about the current, it is about having mains voltage running across the stage.

A relay and supply don't have to be sophisticated. Relays come in AC coil versions as well as the common DC versions. Your supply in the cab could be nothing more than a low voltage transformer. A little 6v transformer should be easy to find, and 6VAC relays. Or 12v or 24v. All are common transformer voltages and rrelays come in the same voltages.

[woodyc]

Yeah, you guys are right. Actuaries probably can probably tell you the exact odds of a footswitch ending up in a pitcher of beer or a vagina or something.

The relay is unfortunate but necessary.

[woodyc]

Well, I ended up using 12VDC, two relays (on/off and fast/slow), and a Marshall-type two button footswitch.

The relay setup wasn't all that expensive, maybe $40-$50 in parts/shipping. But the design, schematic, layout, spec-ing and sourcing parts, et cetera for the relay electronics took a full day in labor. Luckily, all the original Leslie parts came free, so I won't be taking a loss on it.

If anybody needs the relay design/parts list, I'd be happy to pass it along.

The thing sounds great, and its a lot more portable than most Leslies. Here's a pic.

[woodyc]

I did the same relay thing to a Leslie 16 last week, and took a pic this time.



Its not hard or expensive and makes Vibratone-style leslies more flexible (i.e. not requiring 4, 5, or 6 pin connectors, a dangling crossover, et cetera.)

If you mount the box next to the motors like this, the existing motor wires are just long enough to get to the relay. And 12VDC is convenient since you can use a standard footswitch with LEDs. I use the left button for on/off and the right for fast/slow. The only other mod is to put a jackplate on the leslie somewhere to plug the speaker into your amp.

If anybody else has modded these, I'd love to see what you did.

[woodyc]

There isn't much to it...



Anyone know of a cheap triac chip that could do the job of the relays/caps?

[J M Fahey]

Not really.
Fact is relays allow you to keep live and control wiring safe, separate, and in a simple way; Triacs do not.

[Jazz P Bass]

Not to mention numerous codes that should be followed.

[woodyc]

Not really.
Fact is relays allow you to keep live and control wiring safe, separate, and in a simple way; Triacs do not.

I've never used any but... aren't there lots of motor control SSR chips on the market with optical coupling?

just for example... http://www.teledynerelays.com/pdf/industrial/g.pdf

[J M Fahey]

Yes, there are.
But you are building just one (or two), and you already have a working solution to your problem.
Designing an SS controller/driver is possible, of course, you'll also have to design a PCB (and make it), said PCB being "all in one", meaning on the same one you'll have human accessible sections and live voltage ones so you'll have to follow certain strict safety design rules, you'll have to *guarantee* more than, say, "X" Megohms insulation between both sections, guarantee creepage distances, etc.
All that is much easier to accomplish using relays (which usually have greater separation between coil pins and contacts); you can even avoid having the relays on a PCB, you can fly regular wires straight to the contacts, etc.

Mind you, the electromechanical circuit posted above seems to be designed by an amateur , but being simple it has no big design problems; I would not trust so much a complex design from the same source.

It all boils down to how many do you want to build.

[woodyc]

...Mind you, the electromechanical circuit posted above seems to be designed by an amateur , but being simple it has no big design problems; I would not trust so much a complex design from the same source...

Juan,

If you have a more "professional" and "trustworthy" design for for controlling a leslie, please share it.

Your insults aren't really all that helpful.

[J M Fahey]

I beg your pardon?
Where do you see an insult? Please elaborate.

Calling an amateur design amateur is not an insult in my book.

If you want to see a professional and trustworthy design to control a Leslie, by the way, look at how Leslie themselves do it.
A few examples:







Ok, maybe I'm too modern, let's go backwards, to a Tube Classic, full of Mojo:



Want more? There's dozens of them.

Surprisingly (or not), most share ideas I've posted earlier.

[Steve Conner]

I don't see anything wrong with Woody's original circuit. It's more elegant than the Leslie one that uses triacs triggered by relays. (presumably the intent was to minimise pops in the audio by getting zero-current turnoff)

Triac-output SSRs will do fine. No safety issue, they have optical isolation inside and are available in packages festooned with safety approval marks, with the same clearances as regular relays. Crydom are a big manufacturer of the things.