Making a footswitch for a leslie clone.

[thepannist]

I recently bought a Cordovox CL-10 off of ebay.  It is a great sounding 2 speed Leslie in a small cabinet.  The problem is that the only way to turn it on and off  (and switch between fast and slow)is the rocker switches on the top of the cab.  I need your help to make one though, as these are definitely not the kind of electronics that I normally see.  Here is a picture of what the back of the switch looks like:



There are three different tubes filled with some sort of metallic liquid.  When the rocker switches move to the on position, the liquid in containers A and C connect with the 2 wires inside.  Since B is reversed, it connects when the switch is in the off position.  The "leslie trem" switch controls containers B and C while the "Main chorus reverb" switch controls container A.  

Now for the wiring.  Here is a picture of what I am describing, so this doesn't read like some word puzzle.  



Each container has 2 wires coming out of them.  Container A is connected with the left wire to an orange wire.  The right wire is connected to the left wire of Container B.  Container B's right wire goes to the brown wire. Container C's left wire goes to the brown wire as well.  Container C's right wire goes to the red wire.  The red, orange and brown wires connect to a 5 point leslie plug:




What I would like to do is to make a footswitch with 2 switches and only one chord going out.  Since there are 3 wires, I assume I will have to do it with a TRS chord.  I can modify the leslie cabinet to accept that so that the TRS plug will go into that leslie plug so it can work with the rest of the leslie.  I would also like some LEDs in there to show me if those two switches are on or off.  Please help me come up with a wiring diagram for this footswitch.  

Thank you for all your time.
Chris Peterson

[thepannist]

I have found something online that tells what the pinouts for the leslie 5-pin switch.  They list colors of the wires that are different than mine (not a big suprise since mine wasn't actually made by Leslie), but I don't think that is a problem.  
 
1    Black       INPUT [Balanced]
2    Gray            AC POWER IN
3    [Shield]       SIGNAL/DC GROUND
4    Blue          AC POWER IN
5    Red          INPUT [Balanced]


So, it looks like on my plug, 4 is the Orange wire, 2 is red, and 1 is brown.  So, Orange is AC Power in, Red is also AC Power In and Brown is Balanced Input.  

So, one input and two ac powers?  Does that make sense at all?  Am I to assume that this doesn't follow the standards set by Leslie (making it all that more confusing)?

Here is another website that talks about connecting an organ to a leslie.  
http://www.captain-foldback.com/Leslie_sub/tips.htm
Possibly helpful in seeing where these pins really go to normally.


Please help.

Chris

[NoFi]

That doesn't really make sense. At the switch i guess you should have the AC "in", and two AC "outs" going to the motors. It could probably help to know what's connected at the female end of the plug, the pinout listing would probably make more sense there.

I'm not sure if it is really safe to have the AC going through a TRS jack to a footswitch. At least that's why for my vibratone i built a simple switching circuit. Basically, it just switches the AC between the two motors by using relays.
(schem + layouts) :
http://thebin.free.fr/Leslie/

Then all you need is a double footswitch and you get On/off with one switch, and slow/fast with the other.

[thepannist]

Alright, I have mapped out what that leslie 5-pin connector was connected to.  


Ok, so let me infer a few things from here, and hopefully someone can correct me if I am wrong.  The orange wire from switch A goes to leslie connector 2 (via the switch connector 4).  The brown wire from switches B and C goes to the AC in (via switch connector 1).  The red wire  from switch C goes to leslie connector 4 (via switch connector 2).  Since I previously found out that Pins 2 and 4 are supposed to carry AC signals, that makes sense.  

As for the comment on relays, that is something that I need to think about.  From what I have read, relays involve using a sliding switch and an electromagnetic coil.  Since it seems that I have an electromagnetic coil in here (that is what I assume that big spool of wire wrapped around a cylinder is), is it possible that I already have a relay system going on, or am I going to have to design a system like NoFi mentioned?

Again, thanks for your help.  I know that this is far too much information, but any help would be greatly appreciated.

Chris

[NoFi]

Hi again, i just found out the auction on Ebay. Nice one !

It looks like you already have a relay, and the switching circuit is in that small metallic box above the speaker, very similar to Vibratones units. There's a footswitch on the pictures, is it not working ?

Anyway, it looks like you were right in the first place. It should work using a TRS jack/footswitch into the leslie plug. To know if it's possible to build a simple double footswitch with LEDS you will need to measure the voltages between those two funky ABC switches and ground in each phase of operation.
The problem i had on mine is that with a standard footswitch the LEDS glow when everything is off.  :twisted:

[thepannist]

Yeah, that box is the layout drawing (couldn't really call it a schematic...) that I drew.  I will measure those and let you know.  Thanks so much for helping me with this.  There are so few people out there that have leslies w/o amps and use them for something other than organ, so it is nice to know that I have some help out there.

Chris

[petemoore]

The metallic liquid is most likely mercury, and those are mercury switches.
 I got one from an AMC Ambassador trunk lid...nice.

[thepannist]

I figured that was mercury, just didn't want to sound dumb by saying mercury when in fact it was something completely different.  


As for the footswitch that I do have, it is only for speaker on/off, which is the only function that I have no desire to have footswitchable.

Thanks for the help.

[thepannist]

OK,
So I took some voltages today.  Just to make sure I did it right, I'll put my exact process.  clipped the black lead from the DMM onto ground. With the red lead, I checked voltages at the 5-pin connector that goes to my mercury switches.  Since they only use pins 1,2 and 4, those were the only ones that I tested.  I set the multimeter to 500 v AC.

The results:

With both switches on, I got 115v at pins 1 and 2.  Pin 4 read 1v.
With both switches off, I got 115v at pin 1.  Pins 2 and 4 read 1v.
With only the leslie switch on (which produces only the fast motor), I got 115v at pins 1 and 2.  Pin 4 read 1v.
With only the "Main Chorus Reverb" switch on (which produces only the slow motor) I got 115v at pin 1.  Pins 2 and 4 read 1v.

So, sounds like I have a lot of volts going through this system, which, if I understand correctly, means I definitely can't have a standard footswitch happening.  Do I have to use relays for sure now?  Am I understanding this correctly?

Thanks,
Chris

[NoFi]

So it was the AC going to the switches after all !
Unless you want the AC running across the stage from the Leslie up to your toes, a circuit with relays is the way to go.
You have two options, either you want to keep the existing switches and you have to build something you can connect to the existing five pin plug, either you build a new circuit that goes directly to the motors.

The circuit i've posted above is designed to switch the AC from one motor (fast) to the other (slow) or cut it completely to turn the rotor off. The circuit has LEDS but the LEDS are on the circuit itslef. I tried it with a marshall footswitch wich has LEDS, one LED turns when the slow motor is engaged but that's all.
I haven't yet tried to figure out if it was possible to wire the LEDS in the footswitch so that the first one shines when the Leslie is turned on (slow), and the second one when the Leslie is on fast.

Maybe that circuit could be connected to the five pin plug and work just the same, you have to find out if the switches on your cab work the same way, just by routing the AC to the motors.

I'm sorry i'd like to explain things better but my English is killing me.  :?
Maybe the guys at plexi palace could be of some help.
http://vintageamps.com/plexiboard/viewtopic.php?t=25994&start=0

[Joe Hart]

You probably already know, but...

PSA time...

If one of the mercury switches breaks, try your damndest NOT to eat the mercury or even snort it. It's pretty dangerous stuff.

Just a warning.
-Joe Hart

[thepannist]

I try to make a habit of not snorting or eating my broken electronic equipment.  

I remember back in high school chemistry that we had a rule not to touch the stuff (one of the only things that has still stuck from high school chem).

Thanks for the help everyone.  I'll post again when I have this project all figured out.

Chris

[thepannist]

Well, I think I have pretty much figured out how I am going to have to do this (with the help of No Fi), and relays are obviously the answer.  The big question is, which relay should I get.  Mouser has thousands.  Anybody who has done this know what kind of relay to get?

Chris

[thepannist]

I just went to visit my uncle who is an engineer at UCLA.  He has the guys who work for NASA working on my leslie, so I should be able to get something working pretty well.  I'll let you know what happens when we get the right relays in.

Thanks,
Chris