Tech Tips from
Captain Foldback, page 4

The Captain's El Cheapo Leslie 147 kit

 

This page is about hooking up a Leslie with the 6W (147) style hook-up to a Hammond spinet organ using the least amount of special parts. I have written the instructions in e-mails umpteen times over the years for different organ/Leslie combinations, but I figured it was time for an actual page for it. This page covers many Leslie models, including 147, 145 and 125.
Please refer to Uncle Harvey's Guide to Leslie Pin-outs for a complete list of models.

Before you begin soldering please read this disclaimer:
  1. The described hook-up is for Leslie cabinets using the 6W or universal input and only for stock US models (117VAC) and export models where the supply voltage is the same as the motor relay voltage (e.g. UK models wired for 250V and with a 250V relay).
     
  2. The following information is provided as-is. I do not guarantee its correctness for all possible combinations of equipment, nor do I accept any liability in connection with this information. If you are not comfortable working with electronics and equipment containing high voltages, you should get a qualified technician to help you.
     
  3. I am only describing the basics of getting started on the hook-up. Fine-tuning for your particular organ may still be needed.
     
  4. The organ and Leslie are assumed to be stock form.
     
Scenario (I like that word)

...ok, so you got this Leslie 145 at the local thrift shop and want to hook it to aunt Ellen's beloved M-100 so you can play Deep Purple (the song or the band - your choice, they both go well on an M-100).

To make it work as cheaply and simply as possible, you need the stuff below.

 
The El Cheapo Spinet Kit - as simple as it gets. Organ speakers sound as normal, Leslie is simply added. No reverb in Leslie (if applicable).
 

Parts needed:

1. Six-pin amphenol socket and end cap

2. On-off switch (hand or foot, your choice) capable of handling 117VAC (or whatever your local supply voltage is). The switch should be of the type single-pole/single throw or SPST. An original Leslie 'half moon' type switch may be used.

3. Some wire capable of safely handling the mains AC voltage of your region. Check your Leslie cable if you need a ball-park figure on the wire gauge.

How to build:

- Prepare three sets of two wires (conductors), one for audio signal (2' / 70cm), one for AC mains (2' / 70cm) and one for motor control (4' / 1.2m).

- Connect the audio signal wires to pins 1 and 6 on the amphenol socket

- Connect one of the AC mains wires to pin 4 and 5 on the amphenol socket

- Join the other AC mains wire with one of the motor control wires (twist together) - and connect them both to pin 3

- Connect the other motor control wire to pin 2 on the amphenol socket

- If your amphenol socket end cap is a one-piece type, make sure to pull all wires through the cap before continuing. If your cap is the two-piece shell type, you may skip this and fit the shell when you are done soldering.

- Connect your switch to the other end of the motor control wires

- Connect your audio signal wires to the organ's speaker output so that pin 1 on the amphenol socket is to ground and pin 6 is to 'hot' signal. If you are not sure which one is which, either look at the schematic for the organ or experiment to get the least hum in the Leslie. Looking at the schematic is especially important if your organ is model M, M-2 or earlier M-3 where the speaker has four wires going to it.

- Connect the AC mains wires to either a regular AC plug (simple) or to a source of switched AC in the organ (advanced). If you are unsure about how to do the latter, stick to a plug and unplug the Leslie from power when you are not playing.

 
 

By now you want more Leslie effect - you would like to disconnect the internal speaker. With a Leslie of this type it's simple. Look to the right.

 

 

Disconnecting the internal speaker is done a little differently, depending on your organ model. In the following I am only concerned with disconnecting the internal speaker(s) so it/they stop sounding and without damaging organ or the Leslie. There are three basic approaches:

1. For solid state organs, simply disconnect one wire from each speaker leaving the wires to the Leslie socket in place.

2. For tube organs, disconnect one wire to the speaker(s). If your organ has four wires going to the speaker, make sure you disconnect one voice coil lead, leaving the field coil connected. Then, either install or engage the Leslie speaker load resistor (depending on model). On Leslie models with a selector knob, start with 16ohms - if it gives you distortion at low levels, try with 8ohms.

 

When I get around to it, I'll describe the even simpler concept of adding a Leslie 147 to a console Hammond.

 

-Captain Foldback

August 24, 2005