Leslie 212s to Passive cab? Return of Son of DIY Leslie Project

[picothinker]

I am starting a new thread, most of the early stages of this project have been well-discussed in the lengthy "Build Your Own Leslie" thread here. I have a Leslie 212s that I want to completely gut and convert to a single channel passive 8ohm cabinet with traditional 2-speed horns and rotor. This is a specialized Wurlitzer-only Leslie with two Rotosonic drums (each with two 5x7), a 15" firing down with no rotor, and an additional 5x7 in a corner.

I hope to switch the horn driver to 8ohm, put an 8 ohm 15" in it, and use a high-powered 8ohm crossover. This crossover is at 800hz, the horn driver rolls off at about 7khz, I hope this will give it "sort of" normal Leslie characteristics. I wish to use it with synth, guitars and general snippets of line-level sources. The ability to use differing amps will be convenient. I do not really desire the original 122/147 tube amp (can't afford it, for one). I am also considering bi-amping with an active crossover.

Here's some pics, I will add more as it progresses:</p>





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The cabinet is routed and glued on three sides for the top shelf, so it will be a fair woodworking project as well to remove the old shelves. Tentatively, I am considering cutting the old top shelf out all the way around, leaving a few inches. I envision setting my new shelf on that remaining lip, and attaching it (but without gluing, to ease troubleshooting).

I have one 2-speed motor I may be able to use, I know I will need fairly standard Leslie hardware (another motor, rotor, horns/bearings).</p>



How can I get a "floor plan" of a normal top shelf's cutouts? Can anyone measure one for me?

The shelf with the 15" in it will probably have to come out for replacement as well, the speaker hole is on the wrong side. I don't know which would be easier, try to put the rotor on the left side (as viewed from the back) under the existing hole, or make a new shelf and put the rotor on the right.. The lower Rotosonic drum's bearings have a routed spot in the floor for it's bearings. How tall is the space in the bottom for a bass rotor? The existing space is about 10 inches vertically.

</p>

Open to suggestions!
</p>

Scott S.</p>

[jimmywilliams]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



Scott,</P>


A few things about the 212 first...</P>


If your top drum is like the one in my 204 (and it seems to be identical), your speakers are 5x7 in that drum. I have seen 6x9s in the top drum of the 205/610 but those are mounted into a slanted opening to allow them to fit. If your total shelf clearance is 8 inches, you can't have 9 inch heightspeakers in there mounted straight vertically. </P>


Remove the lower back panel (contains the SS amp, switching cirtuitry, etc.)enough toget a better photo of the lower motor/drum assembly. I want to see that. Usually the bottom drum is larger and has a single 6x9. Are you sure your bottom rotor has two? Also I want to see the motor stack and the spindle assembly. I suspect the bottom motor stack is single speed but could be wrong - would like to see it either way. From what I can tell the space generator on the shelf above the drum is engaged with the top of the rotosonic spindle.</P>


I may have other questions about this cabinet's stock configuration...</P>


Some thoughts about your planned mods:</P>


If you are putting horns in your upper shelf it would requiresome mods; you will have to hang the motor from the other side of the shelf to allow room for the horns to spin - as far as I can tell the horns will bang into the motor. If you are going to be a "purist" about it you will also have to move the shelf up a few inches so the horn is only speaking out of two louvers instead of three. But at least you have the louvers in the first place.</P>


From what I understand a lower rotosonic drum is taller than a standard baffle rotor, may require a mounting blockto lift upthe bottom spindle bearing assembly. If you are not putting an amp in here it doesn't matter if the lower rotor is on the left or right (at least it would not matter to me!) as long as you have all the louvers you need on all sides. If you are removing the SS amp you will also need a new louvered back panel too.</P>


Gotta get back to work ... will check in later.</P>


-jim</P>
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[picothinker]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



Several hours after I drew up that pic, I realized that of course 9" speakers cannot fit into an 8" space... It was late night, the day I did the pickup trip when I did that. At the time I was wondering how tall a normal top shelf space was.
</p>

Since the top shelf is routed for the belts, and it looks to be hard to get the old shelf out, I tentatively plan to cut the old shelf out, leaving a lip to mount a new shelf on. It would be easy enough to put blocks all around to raise the horns to only use two louvers. How much difference would that make? I am not too much of a purist obviously, even doing a project like this. I would prefer it to have approximate 122/147 characteristics.
</p>

I planned to invert the existing top motor to hang it in the normal configuration. Tonight I will power up the motors, I would like to verify that at least the slow speed is about 40 RPM, that will be easy enough to count. I can patch in 120 VAC safely. I had read that some rotors with two scoops ran at half-speed. Is a Rotosonic with two speakers a similar situation? I know that I will need the proper pulley and idler.</p>

Steven Cyr's Leslie Project has a lot in common with mine. He replaced a lower Rotosonic drum with a rotor, and had to raise the lower rotor bearings. I see his has 6 lower louvers, mine has 4.</p>

I had the lower panel off that first night and took some pics, but in my darkened garage, the pics were poor. At the time I *think* I spun it by hand and noticed two. I was freshly surprised at the time that there were two in the upper shelf. From what I have read, I think the lower drum is fast or off. Here is the best pic of the lower space. I did not pull the back panel/amp very far out.
</p>

</p>

I do not plan for an amp inside at all, so I don't care which side the rotor is on. I am mostly interested at this point which side would have less custom woodworking to make work!</p>

Thanks for the info! You (all of you) are educating a n00b.</p>

Scott S. </p>

EDIT: changed the above 6x9" references to 5x7" so that I look less like an idiot.
</p>

[redoctoberff]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



Hey Jim,</p>

On the back panel issue, I'm not sure why (maybe they get lost) but I've seen a lot of 122/147 type Leslies in videos and pictures (as well as a couple in person) that had no lower back panel--it was just open like the top. It probably doesn't make a ton of difference in the sound as long as three sides have louvres, and since it would probably be a pain to get ahold of a back panel (especially designed to fit this particular cab, if the dimensions differ greatly from the 122 style cab) I think it's fine to do without that. It doesn't seem to be a problem with the horn on the top.
</p>

[jimmywilliams]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



redoctoberff ,</P>


Yes sometimes they take off the top and bottom back panels (yes the horn chamber on those Leslies does have a back panel too - but it is just a board with no louvers) - maybe so that the cabinet can throw more sound around? Maybe because it "looks cool" to see the rotors spinning? I really don't know. My 204 cabinet is missing the top back panel - if the 212 has one it would be the right size for my cab(it is shorter than the standard bottom panel but does have louvers). I prefer to have them if only to preventthings (animate or otherwise!) from getting into the cabinet. FYI the lower back panel for this cabinet should be the same as the 122/147/etc.because the form factorappears to bethe same as the 147 - as far as I am aware, that is. I could be wrong.</P>


What Scott has going for him are the top louvers on all 3 sides - there were very few non-horn Leslie models that had the smaller rotosonic drum in the top chamber (202, 202S, 204, 205, 212, 212S, and 610 are the only ones I can think of now...). Since he doesn't care about what side the scoop baffle will go, he is better off just putting it right under the 15" speaker hole - what do you think? Of course this will require moving the motor and all that. Or he could "cheat" and just replace the roto drum with a scoop baffle and have some of the 15" firing into it!</P>


Scott - the lower motor stack wasn't in your photo of the lower drum. Can you please post a different photo that shows it? I'd like to see how it is configured, where it is mounted, etc. Your top motor should be fine - and I believe it would already have the smaller pulley on it - not a 3-position one like with the horns but it should be OK (compare the pulley size to the one on the lower motor to be sure). You could always replace just the pulley as well. The motors should not spin any slower for the top roto drum - they should be "stock" motors. But since there are two speakers in the drum, the tremolo is less "pronounced" and creates a seemingly "slower" effect - and then there is the different pulley size too. The standard Leslie horns only have one speaking horn - if both were speaking you would also notice a less pronounced tremolo effect there too because as one would be dying away the other would be coming back - you wouldn't have the entire "cycle" like you do with just one.</P>


- jim</P>
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[redoctoberff]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



Jim,</p>

That's interesting, I don't think I've ever actually seen one with a top panel. I completely believe you, but it's weird that the practice of removing them is so commonplace! It probably is just so you can see the rotors turning, maybe to be able to visually check that things are spinning. I was certain the bottom didn't have a panel either until I searched Google and saw that I was wrong. I wonder how rare those back panels are.</p>

I'd agree on putting the baffle under the 15" for the most "balanced" effect--I don't really know, but it seems like you wouldn't want the baffle to be off center. It might not actually make a difference. I would say, try it out without moving the motors (if that's even possible) and if it sounds off, adjust accordingly. Though, if this is a single speed motor, it'll have to be replaced anyway, even if you can use the same mounting space. You might be able to adjust for the differences using pulleys. I got my pulley off ebay, supposedly an authentic Leslie pull, for $11 shipped, and it seems to work fine.</p>

I'd also like to see a photo of the lower motor stack, though, before drawing any conclusions.
</p>

[picothinker]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



I've read that many early rock 'n roll guys ran the "ugly side out" without covers, in a (vain?) attempt to squeeze a bit more volume out of them. The 40 watt tube amp on 10 gives the 'good kind of distortion', but it's nothing in volume compared to a 40 watt Class A guitar amp. Picture a Fender Twin cranked up, there's hardly any comparison. This had three panels on back, the top is about 3/8" thick and louvered. It has a 7.25" x 2.5" cutout on the lower left, right where the top motor is. The back is solid 3/4" plywood, the bottom is metal with three vertical rows of small stamped louvers. Most of the amp except for the transformers is mounted on the inside of the bottom panel, looks like some power transistors are heat-sinked there.
</p>

I got to work on the 212s tonight, it went very well. I noted '115 VAC' on the upper motor stack so I knew it would be safe to try. I patched two regular AC cords into each motor, and it spun right up. There was a tiny bit of physical hum from the motors, but not bad. Two feet away and I couldn't hear it at all. The top drum spun very quietly in both slow and fast. In fast I could hear a little bit of wind noise. I stuck a bit of white tape on the drum, and could easily count 21 RPM in slow. I had been wondering if it might be half-speed with two speakers, like the double-scoop bass rotors.

</p>

Fast was harder to count. If I put a long skinny vertical stripe of tape and dimmed the lights, I could tell it was going by. I had my wife operate a stopwatch, and decided to count for two minutes, then divide by two. That would give me a slightly better margin of error than one minute. I counted about 320 revolutions in two minutes, making it about 160 RPM. I know that traditional horns should be about 40/400 RPM (I probably couldn't count that speed). I can't see the size of the lower pulley on the top Rotosonic drum, it is on the bottom of the drum, and there is a belt track routed in the top shelf. With proper pulley sizes, perhaps this is possible to get in the correct speed range?

</p>

Greatly cheered by this, I decided to patch some audio into the top drum only. I did not want to try to figure out any existing amp or crossover connections, but the two leads from the Mercotac connector looked inviting. I patched into those, and with a 9V battery verified the polarity. Now I just needed something to play through it. I knew that the headphone output of a Walkman (er, I mean iPod, yeah, that's it) would not drive any speaker directly very well at all. </p>

My current music room is in complete disarray from a recent flood, everything is boxed up and stored in several rooms. After some rummaging, I came across the bare minimum. A keyboard and an amp.

</p>

The keyboard was little small Yamaha DX-100 (4-operator FM, with mini-keys). I have owned it since 1986, but haven't powered it up for a couple of years. Finding a more or less correct wall-wart, I was happy to see it light up. This thing has a great memory backup battery, all my patches were still there from 1986! The amp was an old solid-state Peavey Standard guitar amp. I have owned it since 1973. It is a lousy guitar amp, but a good clean loud amp, I have played keyboards at live gigs through it several times over the decades. I prefer to play directly through the PA with a small monitor, but if there's not enough PA, that's the loudest stage amp I have. Through it's original cab with six 10" speakers, it can keep up adequately. It's 130 watts into a 4 ohm load, but I figured that a few minutes at "very quiet level" wouldn't hurt the amp.
</p>


I positioned my wife at an extension cord "this one is fast, this one is slow". She could only plug in one or the other. I found some of the cheesy organ patches on the little Yamaha, and of course, the swirly made it all 100% better. Yes, I stumbled through 'Whiter Shade of Pale'.The top drum was clear, with no fizzies or buzzing.
</p>


I mainly did this, because while the original Craigslist ad said "perfect condition", and when I first called the guy, I could hear him diddling around in the background on an organ. I was not able to hear this operate in person however. He was moving the day after I called him, and I couldn't get there for a couple of days. He took his Wurlitzer, and left the Leslie with his roommate. Even though I only really want the cab, I hope to Ebay some of the guts, and wanted to verify that the whole thing wasn't a smoking wreck. I only tried one drum, but was glad to see it be pretty much perfect. After letting it spin on both high and low for about ten minutes, the motors were only slightly warm. I am sure a motor disassembly and cleaning/lube is in order.

</p>

Jim, in response to your question about the lower drum, it is also a two-speaker drum. A quick look with a tape measure shows that it is a 5x7" drum, probably identical to the top one. Spinning the bottom drum by hand produces a bit of what sounds like bearing noise, but it could be just me spinning the space generator stuff without it all engaged. I don't yet know much about that. It spun smoothly and easily, I just could hear a tiny bit of rumble. I don't want either of these drums anyway, I hope to replace it with a normal bass rotor and horns.

My pictures tonight are poor again, working in a garage with a flashlight. Here is my temporary test setup.</p>


</p>

I was able to get the back panel (which is most of the amp) aside enough to get a pic of the lower drum's motor stack. I had read several places that the lower drum was fast only, but it looks like the same motor stack as above, hanging down in the more normal configuration. There are two sets of wires going to the lower motor, I believe it is 2-speed as well. The speaker hole overlaps the lower drum by almost half. If I put a rotor in there, it would surely be lessened.</p>


</p>

Beside the 15" speaker, underneath a small wooden shelf is another motor, looks like the smaller half of the 2-speed stack.I am taking these pictures practically standing on my head, with a flashlight. You can barely see the motor between the wires.</p>


</p>

Here is the top of the shelf, the shaft in the center sticking up has the half a stack underneath it. It fits on a rubber tire, to move the pulley that is offset. I presume this moves things to change phase, for the space generator? Is that a regular horn idler there also?
</p>

</p>

This is good, I might have two 2-speed motor stacks I can use, and some good drums I could possibly sell. Enough for tonight, it's going on 2am.</p>

zzz,
</p>

Scott S. &gt;|&lt;
</p>

[jimmywilliams]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



Thanks for the photos scott. Well it looks like you are all set with the motors then.I'm surprised it has two dual5x7 drums. That little extra motor does appear to be a space generator motor so I stand corrected from my earlier posts - I spoke to someone with a 102/103 set and he said there were no separate motors - maybe these cabs were different. </P>


I have been baffled figuring out the putpose of the stationary speaker at the top of the cabinet. I have no idea what it is there for since you can't seem to switch from stationary to rotary. Maybe some of the space generator output gets in there? Now I really wish I had the schematics/manuals for these Leslies!</P>


When working witrh the motor stacks - be very careful that you never have both the slow and fast motors plugged in at the same time. Also, keep in mind that the rotosonic drums were heavier too. </P>


Now I get a better picture of what's going on and yes this is going to be a major rebuilding effort. Because of this I did include more info at the end of this message describing how to use the cab as-is - just as a quick alternative so at least you can be using the cabinet in between all the rebuilding.</P>


If you don't want to experiment with the cab as-is, and want to go straight into the rebuilding: you will need to build a motor switching circuit (decide on whether or not you want a "stop" as well). You will need to build an entirely new top shelf (for the horns/driver/etc.) and invert the motor stack.It willbe very difficult to start measuring/drilling/etc. in the existing shelf. Like you said, you can mount your new shelf on the lips of the cut-away old one. Motor stack may also need some springs, etc. but I don't think so in your case - just keep track which stack was the top stack. For the bottom shelf - short of building a new one, you can try to possibly expand the existing speaker hole so that it will be positioned right under where your scoop rotor will go (in the same place the drum is now).Try to leave the motor/belt where it is - the belt should be roughly the same size as the standard scoop rotor belt. You may be able to re-use some of the spindle bearings but either way it will be asignificant effort. If you are not bi-amping you will of course need a crossover.</P>


I would recommend that you do this in a phased approach. I would work on the lower shelf first - get the scoop baffle/spindle in there and get the 15" positioned above it. The scoop baffles and spindles are usually easier to come by. Remember that you can always use the top rotor as your "horns" section until the apporpriate horns/drivers come along. In the meantime you could be assembling your new top shelf as parts become available.</P>


Of course I was only joking about leaving the 15" in place off center - I have no idea what it would sound like though![:)]</P>


On the clock now, so I'll check in tonight.</P>


- jim</P>


PS: Trying to use the cab as-is (if you are interested) : You could send the &gt;800Hz to the top rotor channel and just block off one of the speaker openings (with some foam or something light so you don't throw the drum balance off). The bottom rotor is a little tricky - you would send anything from 120Hz to 800Hz there (also block off one of the speakers), and then below 120Hz to the pedal channel (you rarely get a tremolo effect on frequencies that low anyway).This other connector kit diagram is a little better than the last one: http://mitatechs.org/files/Leslie_ki..._wurlitzer.pdf</P>


Pin 2 carries pedal; Pin 3 carries Lower Drum; Pin 4 carries Upper Drum. AC on pins 8 and 9. Grounding pin 6 switches lower drum to fast. Grounding pin 7 switches upper drum to fast. If either of this pins are not grounded the respective drums will be slow. I am not sure where the switching power itself originates from having neither an organ or Leslie schematic. Pin 1 is ground (audio, etc.).</P>

[picothinker]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



My main goal is to eventually record with this, the recording stuff is completely disassembled and stashed away in boxes. I don't look forward to using that DX-100 to play through it much, so I am probably going to go ahead. I am a packrat of the first degree, and know I am destroying something very obscure to make what many will consider a bastardized 'sort-of' Leslie. I did list this in the for sale forum, just in case it is terribly valuable whole to a Wurly guy, but I don't forsee shipping it. I will hold off on on major disassembly for a few days just in case.
</p>

Since the top floor has a track routed halfway for the belt, I am more comfortable working on a new removable shelf. To use the existing motor/bracket assembly, it wouldn't line up with the horn's pulley, because the motor's pulley is sunk halfway through the shelf into the track. With a removable shelf, if I screw it up, I can make another one. I don't have many power woodworking tools, so it would be easier to take a shelf to a woodworking friend than the whole thing. </p>

I can see leaving the lower motor there, and replacing the drum with a scoop. Mark and cut the new 'half a hole' with a sabre saw, and I could blank the old hole with anything. One change will be that if I cut out a new hole for the speaker, I will have to put support brackets across the hole (as usual). I will have to look again, the motor is suspended by brackets now, I don't know if a new hole will interfere or not. The basic layout for motor--&gt;belt--&gt;drum-or-rotor is in place, I will probably try to keep that. The lower shelf will probably stay in place, and try to work on it there.
</p>

I found an interesting video on disassembling and cleaning the motors that was helpful to me. The actual motor stuff is in Part 2, but helpful to see it all taken apart in real time. It was funny to see him say "well, you shouldn't really use WD-40", as he is hosing it down with WD-40.... I'm not worried about the motor part, I was a farmer for most of my life, I have refurbed many a starter and electric motor. Now I'm a network guy.</p>

I am still thinking about switching. I can imagine using a DPDT relay for basic fast/slow switching of the AC between motors pretty easily. I would choose 12VDC on the coil, to make an easily extendable footswitch assembly that is safer than extending AC. I can see another DPST relay to disconnect the power to coast to a stop (or start from a stop). I have read about a charged cap applying DC upon discharge for a brake, but don't have it in my mind exactly how to do that yet.
</p>

Questions for the day:</p>

1. In that video, it looks like it's a tight fit removing the horns/motor. If I keep some more space (I have three top louvers) to give more room to work, will that affect the horn's sound greatly? A removable shelf will ease this, I know.
</p>

2. Floor plan for the top shelf. Can anyone give me something to go on? Once I get a top bearing/pulley assembly I can approximate, but would rather get it as close to original as I can.</p>

3. Motor position. I see most all top horns with the motor hanging down. I see pics of bass rotors with the motor both up and down. The video mentions how to reverse the direction. I only have one set of "hanging down" brackets. Should I be looking for another set of those for the top, then plan to reverse the motor direction if need be? </p>

4. If I am going to be cutting out around the existing drum, what is a good way to mark the existing center? Make marks around it on the wall, and measure to the bearing, then match that up later? </p>

5. Does the Rotosonic drum use the same bearings as a bass rotor baffle?</p>

thx,</p>

Scott S
</p>

[redoctoberff]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



Scott,</p>

As switching goes, I described a method here http://organforum.com/forums/permali...ead.aspx#90200 that works very well with my own pair of Leslie 2 speed motor stacks--it's essentially the same method Stephen Cyr used on his minus the capacitors, since as long as the amp and motors aren't plugged into the same power source there is no audible pop. (This is one argument in favor of a passive cab, as you're building.) It's actually a very simple circuit to build. However, I would recommend putting the relay on a circuit board as the AC wires slipped and touched on mine at one point--thought I had killed the outlet power in the garage; thank God for GFCI outlets.</p>

As you mentioned, this route is much better in my opinion than using AC, since I would rather have 12V at the console than 120. Doesn't really make sense to me why Leslie used AC for the switching. I built a simple SPST footswitch with a 1/4" jack output so it's detachable: I can just run an instrument cable from the jack in the footswitch to a 1/4" jack on the Leslie that interrupts the signal from the 12V power supply just as a switch on the Leslie itself would, without having to run a long cord from the Leslie that might get caught and/or torn out.
</p>

I was looking for that video when you asked about how to work with the motors. I remember watching it and though I don't really plan to take apart my motors it is pretty interesting still. As for the motor direction, the top motor should hang down and the bottom should face down. Usually the lower drum has the motor up top so there is room for the amp next to the drum, and even though you won't have an amp, it still makes sense to do this so you have both motors in the middle section of the cabinet. That will make wiring your switching circuit easier.
</p>

[jimmywilliams]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



Hi Scott. Earlier today something did occur to me ... the motors stacks on top/bottom are usually in oppsite positions so that the rotors will turn in two different directions. I noticed on yours the bottom motor hangs down, and the upper is upside-down top-mounted.This is the inverse of how these are configured on the 147 cabs. If you can possibly build your top shelf in such a way that the motor remains in the upside-down position, but still allows clearance for the horns, that would be great. If not, you will have to do more work on your lower shelf ... or disassemble/reassemble BOTH armatures of the lower motor stack so that they spin in the opposite direction. Of course, this is only if you want the "stock" effect of the horn/scoop rotating in different directions. </P>


The spindle bearings for rotosonic spindles and the "normal" spindles are identical - at least as far as the ones I have worked with.</P>


About motor speed switching - if you do not want the DC brake it will be easier. You would need two relays. One shold be used to turn the AC power on/off to the speed relay. Leave it so that the power will flow in the off position (default). The speed relay should send the power to the fast motors in the off position (by default), and to the slow motors in the on position. This is assuming that in most cases you will be using the fast tremolo, so this puts less strain on the relays. Thre are numerous speed switching schematics online and there are several different ways to do it. You just have to make absolutely sure that you never apply power to both the slow/fast motors simultaneously.</P>


Others can help you more with the woodworking stuff I hope.</P>


- jim</P>

[redoctoberff]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



Jim,</p>

Just to clarify, would the second relay be used to provide an "off" speed? The fast/slow circuit can be used for both motors using only one relay.
</p>

[jimmywilliams]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project

[quote user="redoctoberff"]


Jim,</P>


Just to clarify, would the second relay be used to provide an "off" speed? The fast/slow circuit can be used for both motors using only one relay.
</P>


[/quote]</P>


The first relay can be used to turn the motor power on or off - turning the relay on will cut the power to the rest of the switching circuit, giving you a "stop" (not a "brake"!). Ifthe first relay remains un-energized(letting the motor power continue into the circuit), then the second relay will either energize the slow motor (relay on) or the fast motor (relay off). </P>


You need relays with two throws to make this work. The first one, while really only an on-off switch, should still have 2 throws; the "normal" throw (unswitched) would let the power through, and the switched throw (meaning the relay is turned on) will cut the power (that throw wired to nothing - at least insulate the switched terminal though!). This way you can extend the life of the relay since keeping it unactivated will let the motor power through (which is what I assume you would want to happen in most cases). The same principle would hold true for the fast/slow relay. It is very common to have the fast speed used, so your unswitched terminal on the relay would be connected to the outlets for the fast motors. If you mostly use slow speed instead, you can reverse this scheme. </P>


I am further assuming that just one side of the AC is going to be switched via the relays. Also, of course, you will need a low voltage DC supply and switches (foot switches would be a good idea) to energize the relays.</P>


I'm sure there are lots of other ways to do it. Many scehmatics are out there...these were just some of my ideas based roughly on how I have seen some old organs with internal leslies operate.</P>


The "universal" leslies (147, 125, etc.) did in fact use a 120vAC relay switching voltage to switch a 120vAC load. Seems strange, but I guess to keepthe hookup kits as "universal" as possible they couldn;t depend on the organ having the particular voltage that DC relays would have needed. Yes that did mean you had AC voltage on your switches/wires and it would be good to avoid that type of design now. Later Leslies did use a low-voltage DC switching mechanism - they also used more complex things like transistor switching, triacs, etc.</P>


- jim</P>
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[picothinker]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project



I apologize in advance for my entry level art skills. I cannot draw at all, but this is how I would do it. I haven't thought more about the brake, but this part is easy. My favorite speed is chorale, so I would default to slow with the fast/slow relay un-energized.
</p>


</p>

Question of the day:</p>

How much current do the motors draw? Mouser has a 10 amp DPDT relay with a 12VDC coil for under USD $10. This is hopefully massive overkill, one set of contacts could handle both motors, and would be worry-free. I would solder it all up, tape it well, and mount to a cab wall.</p>

EDIT: Jim, good point about making the normally unpowered position of the power relay be with contacts closed. That would greatly extend the life of the relay with it doing nothing the majority of the time! I need to amend my scribble to make the power relay DPDT as well. </p>

EDIT: Amended to include Jim's suggestion of a DPDT relay for off/on, and use normally closed for "power on". </p>

EDIT Again: In response to PMs, I think I would like to switch both legs of the AC with DPDT instead of having a common neutral and just switching the hot with SPDT. I have seen enough old outlets wired backwards that I don't want to taste AC by touching something that should be safe.
</p>

[skippy]

Re: Leslie 212s to Passive cab? Return of Son of DIY Leslie Project

[quote user="picothinker"]


I knew that the headphone output of a Walkman (er, I mean iPod, yeah, that's it) would not drive any speaker directly very well at all. </P>


Scott S. &gt;|&lt;
</P>


[/quote]</P>


Hi Scott,</P>


When I recommended a headphone jack output to be applied to your Leslies input socket pinsto test the main and tremolo channels I assumed you were going to test the units amps as well while supplying mains through the appropriate pins of the Leslie socket. I think I learned a long time ago that a headphone out does not drive a speaker. Sorry about giving you the wrong idea.</P>


Cheers,</P>


Skippy</P>