Help me learn to combine circuits.

[Steve_Oakland]

Hello,
I'm new here and newish to electronics.

Here's what I know:
I have two Leslie Speakers (102 & 103) They were meant to be paired for a particular kind of organ. I wan't/need to figure out how to build a box that contains a few different circuits. I know I can find schematics and parts for all the different circuits I need. I can figure out the formulas and schematics. I can build all the different circuits.

Here's what I want to know:
If I need to make a box that has a power supply, a preamp and a crossover with two channels between the frequency separation, where is a good place to find the necessary information to learn how to combine these circuits into this one box? Think like a mixing console channel strip. Pre into the EQ into the Comp., etc.

The goal:
I wan't to be able to make these speakers standalone. I'm hoping to be able to play guitar or sing or plug an organ into them via the respective inputs.

Does this all make sense? This is a project to benefit my already owned gear and to take a leap into this DIY electronics world. Maybe I'm outta my mind. Any pointers would be greatly appreciated.


Lastly, I've read some of the other threads on this. I understand this could be a journey.

[Twiggybush]

Hi Steve, Welcome aboard. You have many questions. Typically a Leslie is an amplified speaker. You did not mention power amps for the speakers. Behringer makes an active crossover for under $100. You will save money by making passive crossovers.
What ever you want to amplify will need a preamp to match. Guitars are mic level while keyboards are generally line level or greater. You won't need to preamp for organs.
You might consider leaving the speakers passive with a crossover and 1/4" jack. Or you may want to include a 1/4" switched jack to eliminate the onboard amp. In that way you can fudge with preamps and power amps out side the speaker box without being stuck with a configuration that you might out grow. Sometimes you want a loud and clean amp while other times you may want distortion at room levels. Choosing amps can be fun. And what about reverb? The new Leslie Studio 12 kinda catches the spirit of where I feel your headed. It's 100 watt solid state with eq and (distortion?). A modeling pedal and any solid state amp would get you there. Anywho, that's my thoughts. Enjoy, Keith

[Steve_Oakland]

Hey Keith. Thanks for your input. These speakers do have tube amps in them. So, a pre is an order. I didn't think about line level signal so thanks for that reminder. First I need to figure out how to build a power supply for these babies. I'll track down the specs and look up the respective circuit to get these things running in the first place. Then I guess I could rig a box with all the different inputs and preamp and start sending signal. Sounds too easy. I feel like I'm missing something here.

Two power supplies. One for each cab. I believe the organ supplied the power originally.
A preamp to amplify signal. (and somehow split in two. maybe an active crossover will split for me)
A crossover so I don't blow the higher frequency cab

I guess I just need to find the respective plugs and pinouts to attach and start testing?

Does this all sound correct to you? Thanks!

P.S. I'm not even gonna think about reverb until I get these things turned on.

[Twiggybush]

I think I understand a little better where your headed. What kind of input is required by those amps? Line level being 1-2 volts or a B3's AO28 preamp which out puts several volts. I'm not familiar with Gulbransen organs. I looked briefly at the 102 schematic and wondered what a T100 output tube was? Do you have an organ or do you want this primarily for guitar? I also wondered why you want individual pre's inside the cabs. Are you not shooting for stereo use which would require only one preamp with split output?
Sorry I have more questions than you. (:

[Steve_Oakland]

Maybe I'm not explaining myself well enough, but I think you're starting to understand, as well. The cabs take a 9 pin connector. I'll have to pull my organ from the wall but I believe it has the same connector. Maybe different voltages. So, yes I have an old Hammond Colonnade. I'd like to be able to use these in stereo for both guitars and my organ. And anything else that I might want to experiment with sound wise. Vocals? Who knows. I'll look into the T100. To make matters more confusing I'll have to figure out which of 4 channels to use for the amps built into the Leslies. My pre circuit will need to split the signal in order to do this. Or, I haven't looked yet, if I get an active crossover maybe it will split the signals for me. Remember when I said this might be a journey? I've been doing a lot of studying on electronics so I can really dive into this and future projects.

So:
power supplies for each cab
Preamp capable of pushing proper voltages
a crossover which may already split
then decide which channel to use on each power amp

[jkrusel]

These cabinets already have complete power supplies for everything, the organ just supplied 115 VAC line power. Each has 4 channels and about 65W of output. AFAIK the inputs are line level. Both have Leslie "Space Generator" circuitry.
Diagrams:

[Steve_Oakland]

I'm glad you chimed in. This is why I started the thread. I'm still inexperienced enough that I can't completely understand the schematics. At least I know how not to get shocked. That said. Need I make a circuit that will cut standard 120v down to 115v or will the built in PS do that for me? Meaning, just run a line to the proper pin for power?

If so it seems I just need a pre for things like guitar inputs. Also, can you give me the gist of space generator circuitry? Or point me in the direction to read about it? Thanks for the schematics.

[jkrusel]

You also have preamps already in the Leslies! As I said I'm pretty sure they are good for line-level inputs.

115 VAC or 120 VAC - interchangeable. Just standard wall socket juice.

Supply AC power and proper audio input and they will speak!

The "Space Generator" effect was Leslie's attempt to create vibrato, similar to the mechanical vibrato scanner on classic Hammonds. It is a mechanical phase shifter that used a motorized, open-plate capacitor. Designed by Leslie and originally used by Gulbransen and Lowrey. The 102 and 103 were originally designed for these organs.

BTW - don't try to plug these directly into your Colonnade, although I have not looked up the pinout for the Hammond, I know that not all 9-pin setups are the same.

[Jan Girardot]

Steve-Oakland;

I just consulted my 1980 Leslie Dial-a-kit and found:

Hammond 333: Leslies 715, 515. 415, 515 about which Note 10 says: "Allow all channels to function separately. Plug-in installation. For Main/Echo Control use mkit 7953."

. . .Jan

[Steve_Oakland]

Jan! Thank you but can you dumb that down for me? This is a kit/adaptor?

- - - Updated - - -

I'm looking these up but won't I still need a crossover to run both units stereo? Geez this is getting confusing. Sorry.

[jkrusel]

You can't expect to get both Leslies working "stereo" since they each do things to the signals so differently.

On the one hand, you have a great number of different paths you can go down when you try to use these two units.

On the other hand, you need to understand what they can and can't do with the signals that you can feed them.

The choice (an informed choice) needs to be yours. They were designed for a specific purpose, any re-use of these capabilities, for another purpose, needs to be done by you. Get each one working, put some of your desired signals through them and determine what you can use.

[jdoc]

You can't expect to get both Leslies working "stereo" since they each do things to the signals so differently.

On the one hand, you have a great number of different paths you can go down when you try to use these two units.

On the other hand, you need to understand what they can and can't do with the signals that you can feed them.

The choice (an informed choice) needs to be yours. They were designed for a specific purpose, any re-use of these capabilities, for another purpose, needs to be done by you. Get each one working, put some of your desired signals through them and determine what you can use.

finally a good answer, jkrusel is spot on, you may spend a lot of time and money only to get a very disappointing outcome, these a specialized units of very little value unless you have the organ to go with them. To be harsh......parts units.

[jkrusel]

finally a good answer, jkrusel is spot on, you may spend a lot of time and money only to get a very disappointing outcome, these a specialized units of very little value unless you have the organ to go with them. To be harsh......parts units.

Or if you can determine how they can be used in more "creative" ways than they were designed for. I'd give my eye teeth for these things if they are working - heck, EIGHT amps, 3 rotary speaker setups, 3 Space Generator circuits - and SELF CONTAINED, complete with PS and preamps and multiple speakers. WOW!

But, unless you can plug them into the Gullys or Lowreys they were designed for you got design work to do. Otherwise as jdoc points out - parts units. Sigh... what a waste if they go that way.

[jdoc]

yes , could be fun in a weird way or weird in a fun way

[Doddy.van.Straaten]

If I need to make a box that has a power supply, a preamp and a crossover with two channels between the frequency separation, where is a good place to find the necessary information to learn how to combine these circuits into this one box? Think like a mixing console channel strip. Pre into the EQ into the Comp., etc.

There are boxes built exactly for the purpose of connecting the Leslie 102 and 103 cabinets.

It is called a Gulbransen Rialto II! B-)B-)B-)



The service and repair manual contains all the circuitry you will require to separate the audio signals.