passive leslie

[joelw]

I'm considering building a leslie style speaker cab that i can plug my marshall 100w head straight into. Anyone have any experience w/ this. I'm looking for input on things like speakers (I was thinking a 15" and a horn driver), horn design (diffuser cone?), crossover design, and spinning it (should i spin both sides with one motor or should i use two different ones. I am just starting to look into this and have gotten most of my information from http://www.theatreorgans.com/hammond...y/mystery.html
If anyone has experience or ideas about this id love to hear them, and if anyone could point me to other resources it would be appreciated.
thanks

[bbartilson]

I'm considering building a leslie style speaker cab that i can plug my marshall 100w head straight into. Anyone have any experience w/ this.

I have several Leslies. They are indeed a unique sound, and a cool special effect.

Years ago I had a single 12" that was off some higher line off-brand organ. It was a cool sound, but lacking in low end. Box just didn't develop enough throat in that cabinet.

My regular (a 51C converted to 147 style with slow) is great for clean tones, and even a semi-dirty thing. But the stock horn drivers are quite fragile. I'd not plug any sort of Marshall into it and expect it to survive - just too much high mid content.

I also used this Leslie as a passive cabinet for the keyboard player with a Mesa driving it, and that worked pretty well. The stock amp just couldn't keep up with the stage volume, and the Mesa did the job. I don't think I would have dared plug a guitar in on the hot channel though.

The other thing I've found, and what I like the best, is these little units that actually came INSIDE certain console organs. I have a pair that use 10's, and they do slow and fast, and an EVM 10 simply screams. Stereo Leslies? Yep, it's cool.

There are still plenty of organs in the local "Run your ad 'til it sells' newspaper around here. Don't know if it's the same where you are, but that would be my angle if I was looking for more of them. Go visit a few people and find one with the spinning baffle. Take the organ off their hands for free or $20, and build a box around the Leslie unit. Replace the stock 10" after you blow the first one up in a couple hours (don't ask me how I know). I can't advise you on what to do with the organ.

If you truly want to buy and use some 122/147 variant with a horn, take the Leslie driver off, and replace it with the heaviest 1" driver you can find. An EV1823M would be the best. Probably good to run a tail light bulb in series with the horn as well. The 15 may or may not survive, depending on it's history.

Don't forget to learn about the motors and the switching, and whether that stuff needs oil or not. Some do, some don't. Don't forget the rotors may need oil too.

Then, buy some earplugs. That horn will make you deaf.

-Bill

[bbartilson]

I'm considering building a leslie style speaker cab

I shoulda gone and looked first.

http://tinyurl.com/32gts5

From what I can tell, this is the EXACT unit of which I have two.

If it doesn't interest you, make sure to let me know, because I'd love to have a complete spare, and I'd buy it in a heartbeat.

[Enzo]

Bill, you know anyone selling diaphragms for the 1823M? I have a box of them needing same. LAst time I talked to EV - a long time ago now - they no longer had them and told me the tooling for them was damaged in the move and there would not be any more. perhaps someone makes a retrofit diaph? Ther are certainly enough of those drivers out there.

[joelw]

thanks for the responses.

I couldn't tell what size speaker that ebay baffle was for. I asked the seller. If it is not 15" i'm not interested, and if it is, i'll get back to you on whether or not i'm interested by wed(as long as he responds).

As far as horns go, do you guys think i could find anything that wont be too shrill? I want a warm sound, but i feel like the horn is necessary for a leslie sound. My amp itself is unusually warm for a marshall (i didn't think i liked marshalls until i heard mine.) Also, my amp might be slightly over 100w, it has 6550s, but I never crank it past 9 o' clock.

If i decide to use a horn i still have to find or make a crossover that can handle wattage(i'm not sure if wattage is an issue for the ones normally used.) Any ideas? I also found a page in which which someone made their own from leslie which was helpful- http://www.users.bigpond.com/johnacollins/hammond.htm

[bbartilson]

If it is not 15" i'm not interested,

As far as horns go, do you guys think i could find anything that wont be too shrill?

Well, the baffle isn't cut for a 15, I'm sure of that. But enlarging the hole is a small part of the equation. You're talking about building one - which means you need a drive system, a system to change speeds, and a rotating baffle of some kind. All of those parts are there, and they are the hard parts to invent.

The kicker is that it all needs to work quietly. Designing and building the rotating parts is not something I would care to do, and I'm certainly capable of doing so.

Whether you end up using the whole thing as it, part of it, or merely gain ideas for building your own, it's well worth the money. If you chance buying it and don't want it - I'll certainly buy it from you.

As for the horn part of the equation - That becomes a little more complex answer. If it were mine to do, and I wanted a Marshall tone that was usable through a Leslie, I would:

1. Get a speaker that was beefy enough to handle the power of the Marshall itself.
2. Take a signal off of the speaker leads inside the Leslie, and use that to drive another (small) amp to drive the horn, in front of which I would put an eq. (Even one of those Boss pedal eq's would work) Then you could have control over how much high end there was, as well as shape the frequency to your liking. Basically a bi-amp guitar rig for the Leslie.

Certainly you can build your own, and if that's the experience you desire, I'll help as much as I can. Years at a bench means that I think of the shortest path to resolution, hence my suggestion that you buy a wheel instead of inventing one. In your case, inventing one may be half of the fun.

I was at least smart enough not to suggest one of those Motion Sound things. That would be TOO easy.

-Bill

[bbartilson]

Bill, you know anyone selling diaphragms for the 1823M?

89522, right?

Either they are back in production, or someone found a stockpile. Googling 1823m replacement found several sources of what appear to be stock EV parts.

Once you get the diaphragms, let me know. I want a couple out of that box of old drivers. I needs me another talk box.

http://diaphragmdepot.com/ElectroVoice.htm

http://www.speakerrepair.com/ocsdiaphragms.html

Or just call EV. I think it's the Alabama plant now. So much for Buchanan. Life was a lot easier then.

-B

-B

[Enzo]

1823M (new) 89521B
1823M (old) 89521A

From my EV listing dated 1996

89522A fits the 1824S

The 89521A also does fit the 1824M so perhaps the 89522 will fit the 1823M and work there even if it may be "wrong."

I haven't looked lately.

[joelw]

I'm going to go ahead and buy that baffle on ebay and just make a one speaker vibratone thing for now, adding a horn later if i feel the need.

If i end up adding the horn later using this method-

2. Take a signal off of the speaker leads inside the Leslie, and use that to drive another (small) amp to drive the horn, in front of which I would put an eq. (Even one of those Boss pedal eq's would work) Then you could have control over how much high end there was, as well as shape the frequency to your liking. Basically a bi-amp guitar rig for the Leslie.

,then what kind of circuit would i use to get a signal from the leads to the appropriate level.

thanks again for the input.

[bbartilson]

The 89521A also does fit the 1824M so perhaps the 89522 will fit the 1823M and work there even if it may be "wrong."

Me thinks that's the case.

89522 will physically fit, but does not roll off at 6K like the original. I vaguely recall ordering one to try it out at the Washington St. shop. I can't bring to mind what the outcome was. Maybe it stunk. If it was perfect, I would think I would recall the success.

Regardless, those .com dudes list the 89521A and 521B as well.

Do 'we' still have an account with EV? I'll call them tomorrow if you like.

-B

[bbartilson]

I'm going to go ahead and buy that baffle on ebay and just make a one speaker vibratone thing for now, adding a horn later if i feel the need.

Good show. I rather think you'll like it. Offer is still good if you don't.

What circuit to use depends largely on what you're going to drive with the signal. You need to make the signal level appropriate with whatever the next stage is. Direct box or signal transformer are two possibilities. If you build (or otherwise employ) a small power amp entirely contained within the box, you could likely get away with running leads off the speaker directly to the input, and using the amps controls. Using a pedal eq and another guitar amp would require you to attenuate the speaker signal pretty significantly before the input of the eq. Still not a big deal. Add a resistor to your pot circuit and you've got a nice voltage divider/pad.

Keep me posted on how it works out.

-B

[Enzo]

Ah yes, M for midrange. I have no idea if my account still stands, I have had very little occasion to order from EV in recent years. If phragms are available again, great, I can resurrect these things.

I think if I were going to go for a better driver for a Leslie horn I would just get a new EMinence driver or even a PV 22. Both good drivers, both in current production, and replacement parts also in production and available all over. Reasonable prices, and no-solder screw-on diaphraqm replacement.

I have a Wurlitzer Leslie cab in the garage, maybe I ought to make it a springtime project.